Notice2025-03967
Takes of Marine Mammals Incidental to Specified Activities; Taking Marine Mammals Incidental to U.S. Coast Guard Base Kodiak Homeporting Facility in Kodiak, Alaska
Primary source
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Published
March 14, 2025
Issuing agencies
Commerce DepartmentNational Oceanic and Atmospheric Administration
Abstract
NMFS has received a request from the U.S. Coast Guard (USCG) for authorization to take marine mammals incidental to 2 years of construction activities associated with the Base Kodiak Homeporting Facility project in Womens Bay, 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 a possible one-time, 1-year renewal that could be issued under certain circumstances and if all requirements are met, as described in Request for Public Comments at the end of this notice. NMFS will consider public comments prior to making any final decision on the issuance of the requested MMPA authorization and agency responses will be summarized in the final notice of our decision.
Full Text
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[Federal Register Volume 90, Number 49 (Friday, March 14, 2025)]
[Notices]
[Pages 12204-12232]
From the Federal Register Online via the Government Publishing Office [<a href="http://www.gpo.gov">www.gpo.gov</a>]
[FR Doc No: 2025-03967]
[[Page 12203]]
Vol. 90
Friday,
No. 49
March 14, 2025
Part II
Department of Commerce
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National Oceanic and Atmospheric Administration
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Takes of Marine Mammals Incidental to Specified Activities; Taking
Marine Mammals Incidental to U.S. Coast Guard Base Kodiak Homeporting
Facility in Kodiak, Alaska; Notice
Federal Register / Vol. 90, No. 49 / Friday, March 14, 2025 /
Notices
[[Page 12204]]
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DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
[RTID 0648-XE174]
Takes of Marine Mammals Incidental to Specified Activities;
Taking Marine Mammals Incidental to U.S. Coast Guard Base Kodiak
Homeporting Facility in Kodiak, Alaska
AGENCY: National Marine Fisheries Service (NMFS), National Oceanic and
Atmospheric Administration (NOAA), Commerce.
ACTION: Notice; proposed incidental harassment authorizations; request
for comments on proposed authorization and possible renewal.
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SUMMARY: NMFS has received a request from the U.S. Coast Guard (USCG)
for authorization to take marine mammals incidental to 2 years of
construction activities associated with the Base Kodiak Homeporting
Facility project in Womens Bay, 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 a possible
one-time, 1-year renewal that could be issued under certain
circumstances and if all requirements are met, as described in Request
for Public Comments at the end of this notice. NMFS will consider
public comments prior to making any final decision on the issuance of
the requested MMPA authorization and agency responses will be
summarized in the final notice of our decision.
DATES: Comments and information must be received no later than April
14, 2025.
ADDRESSES: Comments should be addressed to Jolie Harrison, Chief,
Permits and Conservation Division, Office of Protected Resources,
National Marine Fisheries Service and should be submitted via email to
<a href="/cdn-cgi/l/email-protection#96dfc2c6b8d0faf3fbfff8f1d6f8f9f7f7b8f1f9e0"><span class="__cf_email__" data-cfemail="f4bda0a4dab29891999d9a93b49a9b9595da939b82">[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: Kate Fleming, Office of Protected
Resources, NMFS, (301) 427-8401.
SUPPLEMENTARY INFORMATION:
Background
The MMPA prohibits the ``take'' of marine mammals, with certain
exceptions. Sections 101(a)(5)(A) and (D) of the MMPA (16 U.S.C. 1361
et seq.) direct the Secretary of Commerce (as delegated to NMFS) to
allow, upon request, the incidental, but not intentional, taking of
small numbers of marine mammals by U.S. citizens who engage in a
specified activity (other than commercial fishing) within a specified
geographical region if certain findings are made and either regulations
are proposed or, if the taking is limited to harassment, a notice of a
proposed IHA is provided to the public for review.
Authorization for incidental takings shall be granted if NMFS finds
that the taking will have a negligible impact on the species or
stock(s) and will not have an unmitigable adverse impact on the
availability of the species or stock(s) for taking for subsistence uses
(where relevant). Further, NMFS must prescribe the permissible methods
of taking and other ``means of effecting the least practicable adverse
impact'' on the affected species or stocks and their habitat, paying
particular attention to rookeries, mating grounds, and areas of similar
significance, and on the availability of the species or stocks for
taking for certain subsistence uses (referred to in shorthand as
``mitigation''); and requirements pertaining to the monitoring and
reporting of the takings. The definitions of all applicable MMPA
statutory terms cited 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 two
consecutive IHAs) 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 IHAs qualifies to be categorically
excluded from further NEPA review.
We will review all comments submitted in response to this notice
prior to concluding our NEPA process or making a final decision on the
request for two consecutive IHAs.
Summary of Request
On April 8, 2024, NMFS received a request from the USCG for two
consecutive IHAs to take marine mammals incidental to construction
associated with the USCG's Base Kodiak Homeport Facility project in
Womens Bay in Kodiak, Alaska. Following NMFS' review of the application
and associated discussions, the USCG submitted a revised version on
June 14, 2024, July 17, 2024, and November 28, 2024. The application
was deemed adequate and complete on December 7, 2024. The USCG's
request is for take of 12 species of marine mammals, by Level B
harassment and, for Dall's porpoise, harbor porpoise, harbor seal,
northern elephant seal, Steller sea lion, and northern fur seal, Level
A harassment. Neither the USCG nor NMFS expect serious injury or
mortality to result from this activity and, therefore, IHAs are
appropriate.
Description of Proposed Activity
Overview
The USCG plans to upgrade waterfront facilities to construct a
homeport facility for two Fast Response Cutters and two Offshore Patrol
Cutters at Base Kodiak, in Womens Bay, Kodiak, Alaska. The facility
will also provide berthing and supporting infrastructure for temporary
homeporting (up to 5 years) and long-term major maintenance of an
additional Fast Response Cutter to be homeported in Seward, Alaska.
[[Page 12205]]
The activities that have the potential to take marine mammals by
Level A and Level B harassment include removal and installation of
timber, concrete, and steel piles by vibratory or impact pile driving
and down the hole (DTH) drilling. A total of 340 in-water construction
days are planned across 2 years. The first year of construction
activities would begin May 19, 2025 and continue through May 18, 2026,
and the second year of construction activities would begin May 19, 2026
and continue through May 18, 2027.
The USCG has requested the issuance of two consecutive IHAs in
association with the two project years. Given the similarities in
activities between project years, NMFS is issuing a single Federal
Register notice to solicit public comments on the issuance of the two
similar, but separate, IHAs.
Dates and Duration
The USCG anticipates that the project will take place over 2 years.
The Year 1 IHA would be effective from May 19, 2025 through May 18,
2026, and the Year 2 IHA would be effective from May 19, 2026 through
May 18, 2027. The specified activities would occur any time during each
project year, for 7-14 hours each day, depending on time of year,
during daylight hours only. A total of 264 days of in-water work are
planned in Year 1 and 76 construction days of in-water work are planned
in year 2.
Specific Geographic Region
Coast Guard Base Kodiak is located on Womens Bay, a largely
enclosed arm of the larger Chiniak Bay on the northeast side of Kodiak
Island, Alaska's largest island. Womens Bay is separated from the rest
of Chiniak Bay by Nyman Peninsula providing a protected harbor for
Coast Guard vessels. Womens Bay is approximately 3.5 miles (mi) (5.6
kilometers (km)) long and water depths range from 0 to 100 ft (31
meters (m)). Near the planned activities, Womens Bay is approximately
1,700 feet (ft) (519 m) wide and 30 ft (9 m) deep.
The shores of Womens Bay are relatively undeveloped; only the most
inner portion of Womens Bay, which includes Base Kodiak and several
other industries, have significant existing shoreline development. The
peninsula and the inner shore host several waterfront and industrial
uses that support current mission-related USCG operations, including
the operational fuel pier and Cargo Wharf. The Cargo Wharf provides
berthing for Base Kodiak cutters and visiting vessels and is where
project activities are planned.
BILLING CODE 3510-22-P
[[Page 12206]]
[GRAPHIC] [TIFF OMITTED] TN14MR25.000
BILLING CODE 3510-22-C
Detailed Description of the Specified Activity
At Base Kodiak in Womens Bay, Kodiak, Alaska, the USCG is upgrading
existing waterfront and constructing new shore facilities to construct
a homeport facility for two Fast Response Cutters and two Offshore
Patrol Cutters and a temporary homeport facility for an additional Fast
Response Cutter to be homeported in Seward, Alaska. The USCG estimates
that Year 1 activities associated with this IHA would include (1)
demolition of 363 piles (14-in and 24-in timber; 12-in and 14-in steel;
24-in steel filled with concrete) via vibratory removal, pulling, or
cutting (a 1.5 multiplier was added to the total number of existing
piles to be removed to account for uncertainty in the existing site
conditions. As such, 363 piles is a conservative estimate) (table 1);
(2) installation of 217 permanent piles (24-in and 42-in steel; and 24-
inch pre-cast square concrete) piles via vibratory and impact pile
driving and DTH drilling; (3) installation of 488 permanent stone
columns installed below the mudline below mean high water using
vibroflation and replacement to improve soil stability; (4)
installation of 495 permanent stone columns above the mean high water
(in-air work) using vibroflotation and replacement to improve soil
stability;
[[Page 12207]]
and (5) vibratory installation and removal of 94 36-in steel temporary
guide piles. The USCG estimates that Year 2 activities would include
(1) the installation of 75 permanent piles (24-in, 30-in, 36-in, and
42-in steel) via vibratory and impact pile driving and DTH; and (2)
vibratory installation and removal of 44 36-in steel temporary guide
piles. See the IHA application for a site-specific description of
activities.
Vibratory hammers use vibratory drivers to rapidly alternate forces
by rotating eccentric weights. This process ``liquefies'' the soil
surrounding the pile so that the pile can either penetrate or be
removed from the ground with reduced resistance. Vibratory hammers
would be used for all pile extraction of existing piles (14-inch and
24-inch timber piles, 12-inch and 14-inch steel piles, and 24-inch
concrete-filled piles) at an assumed rate of 20 piles per day. For pile
installation of permanent and temporary piles, a vibratory hammer would
likely be used until refusal which is anticipated to take 15 to 20
minutes per pile at a rate of four to six piles per day, after which
either impact and/or DTH drilling would be employed to reach depth.
If piles cannot be removed using vibratory methods, they would be
cut-off at the mudline using a hydraulic chainsaw or hydraulic shearing
device operated by divers.
An impact hammer is a steel device that uses air or ignited fuel to
lift a heavy piston, then allows gravity to drop the piston on top of
the pile, repeating until the pile is driven into the substrate
(Washington State Department of Transportation [WSDOT], 2020). Impact
pile driving is anticipated to occur during pile installation; piles
would be impact-driven at a rate of four to six piles a day in
combination with DTH drilling after vibratory methods have met refusal.
Impact pile driving may also be used during pile proofing.
DTH systems use a combination of percussive and drilling mechanisms
to advance a hole into the rock, with or without simultaneously
advancing a pile or casing into that hole. Drill cuttings and debris at
the rock face are removed by an air-lift exhaust up the inside of the
pile (Guan and Miner, 2020). DTH systems will be used to drill a rock
socket approximately 10 ft (3 m) depth below the pile tip. A rebar cage
would then be inserted from the base of the socket to some distance
into the pile and backfilled with concrete from the base of the socket
to some distance up the pile. DTH methods are anticipated to take 150
minutes per pile with an installation rate of two piles per day.
Vibroflotation and replacement is a type of vibrocompaction
commonly used to partially replace poor soil material by flushing out
the weaker soil and replacing it with granular fill material resulting
in a stone column (VGL, 2023). An approximately 30-in-diameter torpedo-
shaped, vibrating probe (a ``vibroflot'') would be vibrated vertically
into the fill placed within the bulkhead. The resulting hole would then
be backfilled with gravel as the vibroflot is removed to create stone
columns within the substrate. This process would be repeated within a
grid to create stone columns, approximately 2.5 ft (0.8 m) apart.
Installation of vibroflot columns is assumed to require up to 45
minutes of vibratory equipment use per column. Vibroflotation and
replacement would occur above and below the mean high water line.
Vibroflotation and replacement above the mean high water line (i.e.,
135 vibroflots to stabilize some shoreline outside the bulkhead and 360
vibroflots to stabilize the approach bulkhead) is not expected to
result in take of marine mammals as pinnipeds are not known to haulout
within the project area.
Permanent piles would be installed through sand and gravel with a
vibratory hammer until advancement stops. Then, the pile will be driven
to depth with an impact hammer. If design tip elevation is still not
achieved, the contractor will utilize a DTH drill to secure the pile.
Pile depths are expected to be approximately 40 to 70 ft (12 m to 21 m)
below the mudline and estimated to take approximately 1.25 to 4 hours
per pile to be driven, depending on which method is utilized. Temporary
36-inch-diameter piles will be installed and removed using a vibratory
hammer. Soil-stabilizing stone columns will be installed using
vibroflotation and replacement, a type of vibrocompaction commonly used
within offshore fills. To account for unforeseen circumstances like
poor weather, the contractor added a 20 percent contingency to the
number of days of effort for each pile type.
Table 1--Year 1 Summary of Planned Activities
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Number of Number piles Days of effort
Pile size and type piles for for Vibratory piles/ Impact piles/day; -----------------------------------------------
removal installation day; min/pile strikes/pile Vibratory Impact DTH
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Temporary Piles:
36-in Steel................. 94 94 6/day; 20 min/pile N/A............... 38 0 0
Permanent Piles:
14-in Timber................ 158 N/A 20/day; 10 min/ N/A............... 10 N/A N/A
pile.
24-in Timber................ 24 N/A 20/day; 10 min/ N/A............... 2 N/A N/A
pile.
12-in Steel................. 147 N/A 20/day; 10 min/ N/A............... 9 N/A N/A
pile.
14-in Steel................. 30 N/A 20/day; 10 min/ N/A............... 2 N/A N/A
pile.
24-in Steel................. N/A 22 6/day; 20 min/pile 6/day; 1,800 5 5 7
strikes/pile.
42-in Steel................. N/A 160 6/day; 20 min/pile 6/day; 2,400 32 32 48
strikes/pile.
24-in steel filled with 4 N/A 20/day; 10 min/ N/A............... 1 N/A N/A
concrete. pile.
24-in precast square N/A 35 6/day; 20 min/pile 6/day; 2,400 7 7 N/A
concrete. strikes/pile.
Soil stabilizing stone columns:
Vibroflot soil stabilization N/A 488 10/day; 45 min/ N/A............... 59 N/A N/A
columns [below Mean High pile.
Water (MHW)].
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Table 2--Year 2 Summary of Planned Activities
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Number of Number piles Days of effort
Pile size and type piles for for Vibratory piles/ Impact piles/day; -----------------------------------------------
removal installation day; min/pile strikes/pile Vibratory Impact DTH
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Temporary Piles:
[[Page 12208]]
36-in Steel................. 44 44 6/day; 20 min/pile N/A............... 18 0 0
Permanent Piles:
24-in Steel................. N/A 20 6/day; 20 min/pile 6/day; 1,800 4 4 6
strikes/pile.
30-in Steel................. N/A 23 6/day; 20 min/pile 6/day; 1,800 5 5 7
strikes/pile.
36-in Steel................. N/A 8 4/day; 20 min/pile 4/day; 1,800 3 3 3
strikes/pile.
42-in Steel................. N/A 24 6/day; 20 min/pile 6/day; 2,400 5 5 8
strikes/pile.
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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 both proposed IHAs, 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 (M/SI) is anticipated
or proposed to be authorized here, PBR and annual serious injury and
mortality 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 2023 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
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ESA/ MMPA status; Stock abundance (CV,
Common name Scientific name Stock strategic (Y/N) Nmin, most recent PBR Annual M/
\2\ abundance survey) \3\ SI \4\
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Order Artiodactyla--Cetacea--Mysticeti (baleen whales)
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Family Eschrichtiidae:
Gray Whale...................... Eschrichtius robustus.. ENP.................... -, -, 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).
Mexico-North Pacific... T, D, Y N/A (N/A, N/A, 2006) UND 0.57
\6\.
Western-North Pacific.. E, D, Y 1,0844 (0.88, 1,007, \7\ 3.4 \7\ 5.82
2006).
Minke Whale..................... Balaenoptera AK..................... -, -, N N/A (N/A, N/A, N/A) UND 0
acutorostrata. \8\.
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Odontoceti (toothed whales, dolphins, and porpoises)
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Family Delphinidae:
Killer Whale.................... Orcinus orca........... ENP Alaska Resident.... -, -, N 1,920 (N/A, 1,920, 19 1.3
2019) \9\.
ENP Gulf of Alaska, -, -, N 587 (N/A, 587, 2012) 5.9 0.8
Aleutian Islands and \10\.
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
\11\.
Harbor Porpoise................. Phocoena phocoena...... Gulf of Alaska......... -, -, Y 31,046 (0.21, N/A, UND 72
1998).
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Order Carnivora--Pinnipedia
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Family Otariidae (eared seals and
sea lions):
Northern Fur Seal............... Callorhinus ursinus.... Eastern Pacific........ -, D, Y 626,618 (0.2, 530,376, 11,403 373
2019).
Steller Sea Lion................ Eumetopias jubatus..... Western................ E, D, Y 9,837 (N/A, 49,837, 299 267
2022) \12\.
[[Page 12209]]
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 187,697 (N/A, 85,369, 5,122 13.7
2013).
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\1\ Information on the classification of marine mammal species can be found on the web page for The Society for Marine Mammalogy's Committee on Taxonomy
(<a href="https://marinemammalscience.org/science-and-publications/list-marine-mammal-species-subspecies/">https://marinemammalscience.org/science-and-publications/list-marine-mammal-species-subspecies/</a>; Committee on Taxonomy (2022)).
\2\ 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-cause 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.
\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 on upon this estimate and the Nmin, the PBR value is likely negatively biased for the entire stock.
\6\ Abundance estimates are based upon data collected more than 8 years ago and therefore, current estimates are considered unknown.
\7\ PBR in U.S waters = 0.2, M/SI in U.S. waters = 0.06.
\8\ Reliable population estimates are not available for this stock. See Friday et al., 2013 and Zerbini et al., 2006 for additional information on
number of minke whales in Alaska.
\9\ Nest is based upon counts of individuals identified from photo-ID catalogs.
\10\ The most recent abundance estimate is likely unreliable as it covered a small area that may not have included females and juveniles, and did not
account for animals missed on the trackline. The calculated PBR is not a reliable index for the stock as it is based upon a negatively biased minimum
abundance estimate.
\11\ The best available abundance estimate is likely an underestimate for the entire stock because it is based upon a survey that covered only a small
portion of the stock's range.
\12\ Nest is best estimate of counts, which have not been corrected for animals at sea during abundance surveys. Estimates provides are for the United
States 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 construction area are included in
table 3-1 of the application for two consecutive IHAs. While North
Pacific right whale and Goose-beaked whales have been reported in
waters off of 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. Goose-
beaked whale prefer deep, pelagic waters and both species would be
considered very rare in the project area. Additionally, USCG initially
requested take for sperm whale, but sperm whale inhabit deep water and
the project area is well outside their range.
In addition, the northern sea otter may be found in Kodiak, Alaska.
However, northern sea otter 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, 2022f).
Two distinct population segments (DPS) of gray whale occur in the
north Pacific: the Eastern North Pacific Distinct Population Segment
(delisted) and the Western North Pacific DPS (Endangered). The Eastern
North Pacific DPS is more likely to occur near Kodiak Archipelago.
During aerial surveys conducted between 1999 and 2005 for Sea Grant
Gulf Apex Predator-Prey Project, gray whales were primarily observed
near Ugak Bay, approximately 30 (km) (17 mi) south of the project area
(straightline) (Sea Grant Alaska, 2012). Smaller numbers of gray whales
were also observed approximately 15 km (9 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 9 km (6 m) north of 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
south east of Kodiak Island as a BIA for Gray Whale for feeding during
June through August, April and May, and September and October. However,
this BIA does not intersect with the project area.
While the shallow waters of Womens Bay do not represent preferred
habitat for large whales, given confirmed gray whale sightings in
Chiniak Bays, and that a small portion of the project area at the mouth
of Womens Bay overlaps with a small portion of a BIA for this species,
gray whales could occur within the project area.
Fin Whale
Fin whales are known to occur in the Kodiak Island area, though
their distributions shift between years (Zerbini et al., 2006). Aerial
surveys conducted between 1999 and 2005 for Sea Grant Gulf Apex
Predator-Prey Project indicate that some of the highest concentrations
of fin whale in the region occur around Kodiak Island (Sea Grant
Alaska, 2012). Across 110 monitoring days between November 10, 2015 and
June 16, 2016 no fin whales were observed during the ferry terminal
reconstruction and dock improvement project in Kodiak Harbor (ABR, Inc.
et al., 2016).
Wild et al. (2023) identified the waters around Kodiak Island
(including a small portion of 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
[[Page 12210]]
comparative significance) and a Data Support score of 2 (moderate
relative confidence in the available supporting data).
There are no known recent observations of fin whale in Womens Bay
and the shallow waters of Womens Bay do not represent preferred habitat
for large whales. However, fin whales do use coastal areas in the Gulf
of Alaska and a small portion of the project area at the mouth of
Womens Bay overlaps with a small portion of a BIA for this species, and
as such, fin whale could occur within the project area.
Humpback Whale
Humpback whales occur along the coastline of the Kodiak
Archipelago, including areas just outside of Womens Bay in Chiniak Bay
(Baraff, 2006; Sea Grant Alaska, 2012). Humpback whales 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., 2016). The highest concentrations occur near Ugak Bay with
numbers peaking in August (Sea Grant Alaska, 2012). Across 110
monitoring days between November 10, 2015 and June 16, 2016 one
humpback whale was observed during the ferry terminal reconstruction
and dock improvement project in Kodiak Harbor (ABR, Inc. et al., 2016).
According to Wade et al., 2023, humpback whales in Kodiak are most
likely to be from the Hawaii DPS (88 percent probability), with an 11
percent probability of being form the threatened Mexico DPS and 1
percent probability of being from the endangered Western North Pacific
DPS.
Wild et al. (2023) identified the waters around and to the East of
Kodiak Island as a feeding BIA for humpback whales 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). A small portion of the project area at the mouth of
Womens Bay overlaps with a small portion of this BIA.
While the shallow waters of Womens Bay do not represent preferred
habitat for large whales, given confirmed humpback whale sightings in
Chiniak Bay, and that a small portion of the project area at the mouth
of Womens Bay overlaps with a small portion of this BIA, humpback
whales could occur within the project area
Minke Whale
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., 2014). 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 whale 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
The fish-eating Alaska Resident stock of killer whale most commonly
occurs in nearshore waters near the project area throughout the year.
Transient killer whales are known to frequent the Kodiak Harbor area to
hunt Steller sea lions during the months of February through May (UAF,
2015). A total of 19 killer whales in 4 pods were observed across 110
days of monitoring between November 10, 2015 and June 16, 2016 during
the Kodiak Ferry Terminal Dock Improvements Project, (ABR, Inc., 2016).
The largest of these pods included seven individuals. The Sunaq Tribe
of Kodiak indicated that killer whales have only been observed in the
project area approximately two times in the last 5 years (Van Daele,
2024, personal communication).
Pacific White-Sided Dolphin
Pacific white-sided dolphins sometimes occur in pods of thousands,
but group sizes are usually between 10 and 100 animals (Clark, 2008b;
NMFS, 2022). 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 where 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 Base Kodiak, which is
situated close to the edge of the continental shelf and the Chiniak
trough.
Dall's Porpoise
Several surveys conducted by the National Marine Mammal Laboratory
(NMML) in the late 1990s documented dozens of Dall's porpoises in
waters around Kodiak Island (Hobbs, 2004). They have been documented
around Kodiak Island and occur in nearshore habitats. However, across
110 monitoring days between November 10, 2015 and June 16, 2016 no
Dall's porpoise were observed during the ferry terminal reconstruction
and dock improvement project in Kodiak Harbor (ABR, Inc. et al., 2016),
and the Sunaq Tribe of Kodiak indicates that this species has never
been observed in Womens Bay (Van Daele, 2024, personal communication).
Harbor Porpoise
During the 1992 NMML 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.
Harbor porpoises are known to frequent nearshore habitats,
including bays, and have been documented in bays near the project area
(Van Daele, 2024, personal communication); therefore, harbor porpoises
may intermittently enter the project area.
Northern Elephant Seal
Northern elephant seals are uncommon in Alaskan waters and rarely
seen as far north as Kodiak Island. However, the Sunaq 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 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 seal
were observed during the ferry terminal reconstruction and dock
improvement project in Kodiak Harbor (ABR, Inc. et al., 2016).
[[Page 12211]]
Steller Sea Lion
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 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.
Limited data exist to inform the potential occurrence of Steller
sea lion in Womens Bay. Although the Comprehensive Plan for the Womens
Bay community does note that sea lions inhabit the bay (Kodiak Island
Borough et al, 2006), the Sunaq Tribe of Kodiak suggests that Steller
Sea Lion are rarely observed in Womens Bay. Steller sea lion are more
abundant approximately 9 km northeast of the project area, where the
Kodiak Ferry Terminal project was planned in 2015 (80 FR 51211, August
24, 2015). At this location, Steller sea lions regularly haul out on
the artificial haulout float called Dog Bay in St. Herman Harbor, near
the Kodiak Ferry Terminal. This haulout is not designated as a major
haulout and is not considered Steller Sea Lion critical habitat. A bi-
weekly census of Steller sea lions at the Dog Bay float, was conducted
from November 2015 to June 2016 in association with the Kodiak Ferry
Terminal project, revealing maximum numbers (>100) from mid-March
through mid-June, with 5,111 total observations from November 2015 to
June 2016 (ABR Inc, 2016). Additionally, counts conducted by Protected
Species Observers during the Kodiak Terminal and Dock Improvements
Project documented 6 to 114 Steller sea lion (33 on average)
observations daily (ABR, Inc., 2016).
Harbor Seal
The Sunaq Tribe of Kodiak indicates that large congregations
(approximately 24 individuals) of harbor seals are frequently observed
within the project area, concentrating near Mary's Island to dive for
prey. During the Kodiak Ferry Terminal and Dock Improvements Project
(approximately 6 miles northeast of the Proposed Action), 13 sightings
of seals, with a maximum group size of 3, were reported during the 110
days of monitoring (ABR Inc, 2016).
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.). Note that no direct measurements of
hearing ability have been successfully completed for mysticetes (i.e.,
low-frequency cetaceans). Subsequently, NMFS (2024) described updated
generalized hearing ranges for these marine mammal hearing groups.
Generalized hearing ranges chosen based on the ~65 decibel (dB)
threshold from composite audiograms, previous analyses in NMFS (2019,
and/or data from Southall et al., (2007) and Southall et al., (2019).
Marine mammal hearing groups and their associated hearing ranges are
provided 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 150 Hz to 160 kHz.
(dolphins, toothed whales, beaked
whales, bottlenose whales).
Very High-frequency (VHF) cetaceans 200 Hz to 165 kHz.
(true porpoises, Kogia, river
dolphins, Cephalorhynchid,
Lagenorhynchus cruciger & L.
australis).
Phocid pinnipeds (PW) (underwater) 40 Hz to 90 kHz.
(true seals).
Otariid pinnipeds (OW) (underwater) 60 Hz to 68 kHz.
(sea lions and fur seals).
------------------------------------------------------------------------
* Represents the generalized hearing range for the entire group as a
composite (i.e., all species within the group), where individual
species' hearing ranges may not be as broad. Generalized hearing range
chosen based on ~65 dB threshold from composite audiogram, previous
analysis in NMFS 2018, and/or data from Southall et al., 2007;
Southall et al., 2019. Additionally, animals are able to detect very
loud sounds above and below that ``generalized'' hearing range.
For more detail concerning these groups and associated frequency
ranges, please see NMFS (2024) for a review of available information.
Potential Effects of Specified Activities on Marine Mammals and Their
Habitat
This section provides a discussion of the ways in which components
of the specified activity may impact marine mammals and their habitat.
The Estimated Take of Marine Mammals section later in this document
includes a quantitative analysis of the number of individuals that are
expected to be taken by this activity. The Negligible Impact Analysis
and Determination section considers the content of this section, the
Estimated Take of Marine Mammals section, and the Proposed Mitigation
section, to draw conclusions regarding the likely impacts of these
activities on the reproductive success or survivorship of individuals
and whether those impacts are reasonably expected to, or reasonably
likely to, adversely affect the species or stock through effects on
annual rates of recruitment or survival.
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
[[Page 12212]]
far (American National Standards Institute (ANSI), 1995). The sound
level of an area is defined by the total acoustical energy being
generated by known and unknown sources. These sources may include
physical (e.g., waves, wind, precipitation, earthquakes, ice,
atmospheric sound), biological (e.g., sounds produced by marine
mammals, fish, and invertebrates), and anthropogenic sound (e.g.,
vessels, dredging, aircraft, construction).
The sum of the various natural and anthropogenic sound sources at
any given location and time--which comprise ``ambient'' or
``background'' sound--depends not only on the source levels (as
determined by current weather conditions and levels of biological and
shipping activity) but also on the ability of sound to propagate
through the environment. In turn, sound propagation is dependent on the
spatially and temporally varying properties of the water column and sea
floor, and is frequency-dependent. As a result of the dependence on a
large number of varying factors, ambient sound levels can be expected
to vary widely over both coarse and fine spatial and temporal scales.
Sound levels at a given frequency and location can vary by 10-20 dB
from day to day (Richardson et al., 1995). The result is that,
depending on the source type and its intensity, sound from the
specified activity may be a negligible addition to the local
environment or could form a distinctive signal that may affect marine
mammals.
In-water construction activities associated with the project would
include impact pile driving, vibratory pile driving and removal, and
use of DTH equipment. The sounds produced by these activities fall into
one of two general sound types: impulsive and non-impulsive. Impulsive
sounds (e.g., explosions, gunshots, sonic booms, impact pile driving)
are typically transient, brief (less than 1 second), broadband, and
consist of high peak sound pressure with rapid rise time and rapid
decay (ANSI, 1986; National Institute of Occupational Safety and Health
(NIOSH), 1998; NMFS, 2018). 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).
Three types of hammers would be used on this project: impact,
vibratory, and DTH. Impact hammers operate by repeatedly dropping a
heavy piston onto a pile to drive the pile into the substrate. Sound
generated by impact hammers is characterized by rapid rise times and
high peak levels, a potentially injurious combination (Hastings and
Popper, 2005). Vibratory hammers install piles by vibrating them and
allowing the weight of the hammer to push them into the sediment.
Vibratory hammers produce significantly less sound than impact hammers.
Peak sound pressure levels (SPLs) may be 180 dB or greater, but are
generally 10 to 20 dB lower than SPLs generated during impact pile
driving of the same-sized pile (Oestman et al., 2009). Rise time is
slower, reducing the probability and severity of injury, and sound
energy is distributed over a greater amount of time (Nedwell and
Edwards, 2002; Carlson et al., 2005).
A DTH hammer is essentially a drill bit that drills through the
bedrock using a rotating function like a normal drill, in concert with
a hammering mechanism operated by a pneumatic (or sometimes hydraulic)
component integrated into the DTH hammer to increase speed of progress
through the substrate (i.e., it is similar to a hammer drill hand
tool). The sounds produced by the DTH method contain both continuous,
non-impulsive, component from the drilling action and an impulsive
component from the hammering effect. Therefore, we treat DTH systems as
both impulsive and continuous, non-impulsive sound source types
simultaneously.
The likely or possible impacts of USCG's proposed activity on
marine mammals could involve both non-acoustic and acoustic stressors.
Potential non-acoustic stressors could result from the physical
presence of equipment and personnel; however, any impacts to marine
mammals are expected to be primarily acoustic in nature. Acoustic
stressors include effects of heavy equipment operation during pile
installation and removal.
Acoustic Effects
The introduction of anthropogenic noise into the aquatic
environment from pile driving and removal and DTH is the means by which
marine mammals may be harassed from USCG's specified activity. In
general, animals exposed to natural or anthropogenic sound may
experience behavioral, physiological, and/or physical effects, ranging
in magnitude from none to severe (Southall et al., 2007, 2019). In
general, exposure to pile driving and DTH noise has the potential to
result in behavioral reactions (e.g., avoidance, temporary cessation of
foraging and vocalizing, changes in dive behavior) and, in limited
cases, an auditory threshold shift (TS). Exposure to anthropogenic
noise can also lead to non-observable physiological responses such an
increase in stress hormones. Additional noise in a marine mammal's
habitat can mask acoustic cues used by marine mammals to carry out
daily functions such as communication and predator and prey detection.
The effects of pile driving noise on marine mammals are dependent on
several factors, including, but not limited to, sound type (e.g.,
impulsive vs. non-impulsive), the species, age and sex class (e.g.,
adult male vs. mom with calf), duration of exposure, the distance
between the pile and the animal, received levels, behavior at time of
exposure, and previous history with exposure (Wartzok et al., 2004;
Southall et al., 2007). Here we discuss physical auditory effects (TSs)
followed by behavioral effects and potential impacts on habitat.
NMFS defines a noise-induced TS as a change, usually an increase,
in the threshold of audibility at a specified frequency or portion of
an individual's hearing range above a previously established reference
level (NMFS, 2024). The amount of TS is customarily expressed in dB. A
TS can be permanent or temporary. As described in NMFS (2024), there
are numerous factors to consider when examining the consequence of TS,
including, but not limited to, the signal temporal pattern (e.g.,
impulsive or non-impulsive), likelihood an individual would be exposed
for a long enough duration or to a high enough level to induce a TS,
the magnitude of the TS, time to recovery (seconds to minutes or hours
to days), the frequency range of the exposure (i.e., spectral content),
the hearing and vocalization frequency range of the exposed species
relative to the signal's frequency spectrum (i.e., how animal uses
sound within the frequency band of the signal; e.g., Kastelein et al.,
2014), and the overlap between the animal and the source (e.g.,
spatial, temporal, and spectral).
Auditory Injury and Permanent Threshold Shift (PTS)--NMFS defines
auditory injury (AUD INJ) as ``damage to the inner ear that can result
in destruction of tissue . . . which may or may not result in PTS''
(NMFS, 2024). NMFS defines PTS as a permanent, irreversible increase in
the threshold of
[[Page 12213]]
audibility at a specified frequency or portion of an individual's
hearing range above a previously established reference level (NMFS,
2024). Available data from humans and other terrestrial mammals
indicate that a 40-dB TS approximates PTS onset (Ward et al., 1958,
1959; Ward 1960; Kryter et al., 1966; Miller, 1974; Ahroon et al.,
1996; Henderson et al., 2008). PTS levels for marine mammals are
estimates, as with the exception of a single study unintentionally
inducing PTS in a harbor seal (Kastak et al., 2008), there are no
empirical data measuring PTS in marine mammals largely due to the fact
that, for various ethical reasons, experiments involving anthropogenic
noise exposure at levels inducing PTS are not typically pursued or
authorized (NMFS, 2018).
Temporary Threshold Shift (TTS)--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 (SEL<INF>cum</INF>) in an accelerating fashion: At low
exposures with lower SEL<INF>cum</INF>, the amount of TTS is typically
small and the growth curves have shallow slopes. At exposures with
higher SEL<INF>cum</INF>, the growth curves become steeper and approach
linear relationships with the noise SEL.
Depending on the degree (elevation of threshold in dB), duration
(i.e., recovery time), and frequency range of TTS, and the context in
which it is experienced, TTS can have effects on marine mammals ranging
from discountable to serious (similar to those discussed in Masking,
below). For example, a marine mammal may be able to readily compensate
for a brief, relatively small amount of TTS in a non-critical frequency
range that takes place during a time when the animal is traveling
through the open ocean, where ambient noise is lower and there are not
as many competing sounds present. Alternatively, a larger amount and
longer duration of TTS sustained during time when communication is
critical for successful mother/calf interactions could have more
serious impacts. We note that reduced hearing sensitivity as a simple
function of aging has been observed in marine mammals, as well as
humans and other taxa (Southall et al., 2007), so we can infer that
strategies exist for coping with this condition to some degree, though
likely not without cost.
Many studies have examined noise-induced hearing loss in marine
mammals (see Finneran (2015) and Southall et al. (2019) for summaries).
TTS is the mildest form of hearing impairment that can occur during
exposure to sound (Kryter, 2013). While experiencing TTS, the hearing
threshold rises, and a sound must be at a higher level in order to be
heard. In terrestrial and marine mammals, TTS can last from minutes or
hours to days (in cases of strong TTS). In many cases, hearing
sensitivity recovers rapidly after exposure to the sound ends. For
cetaceans, published data on the onset of TTS are limited to captive
bottlenose dolphin (Tursiops truncatus), beluga whale, harbor porpoise,
and Yangtze finless porpoise (Neophocoena asiaeorientalis) (Southall et
al., 2019). For pinnipeds in water, measurements of TTS are limited to
harbor seals, elephant seals (Mirounga angustirostris), bearded seals
(Erignathus barbatus) and California sea lions (Zalophus californianus)
(Kastak et al., 1999, 2007; Kastelein et al., 2019b, 2019c, 2021,
2022a, 2022b; Reichmuth et al., 2019; Sills et al., 2020). TTS was not
observed in spotted (Phoca largha) and ringed (Pusa hispida) seals
exposed to single airgun impulse sounds at levels matching previous
predictions of TTS onset (Reichmuth et al., 2016). These studies
examine hearing thresholds measured in marine mammals before and after
exposure to intense or long-duration sound exposures. The difference
between the pre-exposure and post-exposure thresholds can be used to
determine the amount of threshold shift at various post-exposure times.
The amount and onset of TTS depends on the exposure frequency.
Sounds at low frequencies, well below the region of best sensitivity
for a species or hearing group, are less hazardous than those at higher
frequencies, near the region of best sensitivity (Finneran and
Schlundt, 2013). At low frequencies, onset-TTS exposure levels are
higher compared to those in the region of best sensitivity (i.e., a low
frequency noise would need to be louder to cause TTS onset when TTS
exposure level is higher), as shown for harbor porpoises and harbor
seals (Kastelein et al., 2019a, 2019c). Note that in general, harbor
seals and harbor porpoises have a lower TTS onset than other measured
pinniped or cetacean species (Finneran, 2015). In addition, TTS can
accumulate across multiple exposures, but the resulting TTS 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, cumulative
SEL will overestimate the amount of TTS from intermittent exposures,
such as sonars and impulsive sources. Nachtigall et al. (2018) describe
measurements of hearing sensitivity of multiple odontocete species
(bottlenose dolphin, harbor porpoise, beluga, and false killer whale
(Pseudorca crassidens)) when a relatively loud sound was preceded by a
warning sound. These captive animals were shown to reduce hearing
sensitivity when warned of an impending intense sound. Based on these
experimental observations of captive animals, the authors suggest that
wild animals may dampen their hearing during prolonged exposures or if
conditioned to anticipate intense sounds. Another study showed that
echolocating animals (including odontocetes) might have anatomical
specializations that might allow for conditioned hearing reduction and
filtering of low-frequency ambient noise, including increased stiffness
and control of middle ear structures and placement of inner ear
structures (Ketten et al., 2021). Data available on noise-induced
hearing loss for mysticetes are currently lacking (NMFS, 2018).
Additionally, the existing marine mammal TTS data come from a limited
number of individuals within these species.
Relationships between TTS and PTS thresholds have not been studied
in marine mammals, and there is no PTS data for cetaceans, but such
relationships are assumed to be similar to those in humans and other
terrestrial mammals. PTS typically occurs at exposure levels at least
several decibels above that inducing mild TTS (e.g., a 40-dB threshold
shift approximates PTS onset (Kryter et al., 1966; Miller, 1974), while
a 6-dB threshold shift approximates TTS onset (Southall et al., 2007,
2019). Based on data from terrestrial mammals, a precautionary
assumption is that the PTS thresholds for impulsive sounds (such as
impact pile driving pulses as received close to the source) are at
least 6 dB higher than the TTS threshold on a peak-pressure basis and
PTS cumulative sound exposure level thresholds are 15 to 20 dB higher
than TTS cumulative sound exposure level thresholds (Southall et al.,
2007, 2019). Given the higher level
[[Page 12214]]
of sound or longer exposure duration necessary to cause PTS as compared
with TTS, it is considerably less likely that PTS could occur.
Activities for this project include impact and vibratory pile
driving and removal and DTH. For the proposed project, these activities
would not occur at that same time and there would likely be pauses in
activities producing the sound during each day. Given these pauses and
the fact that many marine mammals are likely moving through the project
areas and not remaining for extended periods of time, the potential for
TS declines.
Behavioral Harassment--Exposure to noise from pile driving and DTH
also has the potential to behaviorally disturb marine mammals.
Generally speaking, NMFS considers a behavioral disturbance that rises
to the level of harassment under the MMPA a non-minor response--in
other words, not every response qualifies as behavioral disturbance,
and for responses that do, those of a higher level, or accrued across a
longer duration, have the potential to affect foraging, reproduction,
or survival. Behavioral disturbance may include a variety of effects,
including subtle changes in behavior (e.g., minor or brief avoidance of
an area or changes in vocalizations), more conspicuous changes in
similar behavioral activities, and more sustained and/or potentially
severe reactions, such as displacement from or abandonment of high-
quality habitat. Behavioral responses may include changing durations of
surfacing and dives, changing direction and/or speed; reducing/
increasing vocal activities; changing/cessation of certain behavioral
activities (such as socializing or feeding); eliciting a visible
startle response or aggressive behavior (such as tail/fin slapping or
jaw clapping); avoidance of areas where sound sources are located.
Pinnipeds may increase their haul out time, possibly to avoid in-water
disturbance (Thorson and Reyff, 2006). Behavioral responses to sound
are highly variable and context-specific and any reactions depend on
numerous intrinsic and extrinsic factors (e.g., species, state of
maturity, experience, current activity, reproductive state, auditory
sensitivity, time of day), as well as the interplay between factors
(e.g., Richardson et al., 1995; Wartzok et al., 2004; Southall et al.,
2007, 2019; Weilgart, 2007; Archer et al., 2010). Behavioral reactions
can vary not only among individuals but also within an individual,
depending on previous experience with a sound source, context, and
numerous other factors (Ellison et al., 2012), and can vary depending
on characteristics associated with the sound source (e.g., whether it
is moving or stationary, number of sources, distance from the source).
In general, pinnipeds seem more tolerant of, or at least habituate more
quickly to, potentially disturbing underwater sound than do cetaceans,
and generally seem to be less responsive to exposure to industrial
sound than most cetaceans. Please see Appendices B and C of Southall et
al. (2007) and Gomez et al. (2016) for reviews of studies involving
marine mammal behavioral responses to sound.
Habituation can occur when an animal's response to a stimulus wanes
with repeated exposure, usually in the absence of unpleasant associated
events (Wartzok et al., 2004). Animals are most likely to habituate to
sounds that are predictable and unvarying. It is important to note that
habituation is appropriately considered as a ``progressive reduction in
response to stimuli that are perceived as neither aversive nor
beneficial,'' rather than as, more generally, moderation in response to
human disturbance (Bejder et al., 2009). The opposite process is
sensitization, when an unpleasant experience leads to subsequent
responses, often in the form of avoidance, at a lower level of
exposure.
As noted above, behavioral state may affect the type of response.
For example, animals that are resting may show greater behavioral
change in response to disturbing sound levels than animals that are
highly motivated to remain in an area for feeding (Richardson et al.,
1995; Wartzok et al., 2004; National Research Council (NRC), 2005).
Controlled experiments with captive marine mammals have showed
pronounced behavioral reactions, including avoidance of loud sound
sources (Ridgway et al., 1997; Finneran et al., 2003). Observed
responses of wild marine mammals to loud pulsed sound sources (e.g.,
seismic airguns) have been varied but often consist of avoidance
behavior or other behavioral changes (Richardson et al., 1995; Morton
and Symonds, 2002; Nowacek et al., 2007).
Available studies show wide variation in response to underwater
sound; therefore, it is difficult to predict specifically how any given
sound in a particular instance might affect marine mammals perceiving
the signal. If a marine mammal does react briefly to an underwater
sound by changing its behavior or moving a small distance, the impacts
of the change are unlikely to be significant to the individual, let
alone the stock or population. However, if a sound source displaces
marine mammals from an important feeding or breeding area for a
prolonged period, impacts on individuals and populations could be
significant (e.g., Lusseau and Bejder, 2007; Weilgart, 2007; NRC,
2005). However, there are broad categories of potential response, which
we describe in greater detail here, that include alteration of dive
behavior, alteration of foraging behavior, effects to breathing,
interference with or alteration of vocalization, avoidance, and flight.
Changes in dive behavior can vary widely and may consist of
increased or decreased dive times and surface intervals as well as
changes in the rates of ascent and descent during a dive (e.g., Frankel
and Clark, 2000; Costa et al., 2003; Ng and Leung, 2003; Nowacek et
al., 2004; Goldbogen et al., 2013a, 2013b). Variations in dive behavior
may reflect interruptions in biologically significant activities (e.g.,
foraging) or they may be of little biological significance. The impact
of an alteration to dive behavior resulting from an acoustic exposure
depends on what the animal is doing at the time of the exposure and the
type and magnitude of the response.
Disruption of feeding behavior can be difficult to correlate with
anthropogenic sound exposure, so it is usually inferred by observed
displacement from known foraging areas, the appearance of secondary
indicators (e.g., bubble nets or sediment plumes), or changes in dive
behavior. As for other types of behavioral response, the frequency,
duration, and temporal pattern of signal presentation, as well as
differences in species sensitivity, are likely contributing factors to
differences in response in any given circumstance (e.g., Croll et al.,
2001; Nowacek et al., 2004; Madsen et al., 2006; Yazvenko et al.,
2007). A determination of whether foraging disruptions incur fitness
consequences would require information on or estimates of the energetic
requirements of the affected individuals and the relationship between
prey availability, foraging effort and success, and the life history
stage of the animal.
Variations in respiration naturally vary with different behaviors
and alterations to breathing rate as a function of acoustic exposure
can be expected to co-occur with other behavioral reactions, such as a
flight response or an alteration in diving. However, respiration rates
in and of themselves may be representative of annoyance or an acute
stress response. Various studies have shown that respiration rates may
either be unaffected or could increase, depending on the species and
signal characteristics, again highlighting the importance in
understanding species differences in the
[[Page 12215]]
tolerance of underwater noise when determining the potential for
impacts resulting from anthropogenic sound exposure (e.g., Kastelein et
al., 2001, 2005, 2006; Gailey et al., 2007). For example, harbor
porpoise' respiration rate increased in response to pile driving sounds
at and above a received broadband SPL of 136 dB (zero-peak SPL: 151 dB
re 1 micropascal ([mu]Pa); SEL of a single strike: 127 dB re 1
[mu]Pa\2\-s) (Kastelein et al., 2013).
Marine mammals vocalize for different purposes and across multiple
modes, such as whistling, echolocation click production, calling, and
singing. Changes in vocalization behavior in response to anthropogenic
noise can occur for any of these modes and may result from a need to
compete with an increase in background noise or may reflect increased
vigilance or a startle response. For example, in the presence of
potentially masking signals, humpback whales and killer whales have
been observed to increase the length of their songs (Miller et al.,
2000; Fristrup et al., 2003) or vocalizations (Foote et al., 2004),
respectively, while North Atlantic right whales (Eubalaena glacialis)
have been observed to shift the frequency content of their calls upward
while reducing the rate of calling in areas of increased anthropogenic
noise (Parks et al., 2007). In some cases, animals may cease sound
production during production of aversive signals (Bowles et al., 1994).
Avoidance is the displacement of an individual from an area or
migration path as a result of the presence of a sound or other
stressors, and is one of the most obvious manifestations of disturbance
in marine mammals (Richardson et al., 1995). For example, gray whales
are known to change direction--deflecting from customary migratory
paths--in order to avoid noise from seismic surveys (Malme et al.,
1984). Avoidance may be short-term, with animals returning to the area
once the noise has ceased (e.g., Bowles et al., 1994; Goold, 1996;
Stone et al., 2000; Morton and Symonds, 2002; Gailey et al., 2007).
Longer-term displacement is possible, however, which may lead to
changes in abundance or distribution patterns of the affected species
in the affected region if habituation to the presence of the sound does
not occur (e.g., Blackwell et al., 2004; Bejder et al., 2006; Teilmann
et al., 2006).
A flight response is a dramatic change in normal movement to a
directed and rapid movement away from the perceived location of a sound
source. The flight response differs from other avoidance responses in
the intensity of the response (e.g., directed movement, rate of
travel). Relatively little information on flight responses of marine
mammals to anthropogenic signals exist, although observations of flight
responses to the presence of predators have occurred (Connor and
Heithaus, 1996; Bowers et al., 2018). The result of a flight response
could range from brief, temporary exertion and displacement from the
area where the signal provokes flight to, in extreme cases, marine
mammal strandings (England et al., 2001). However, it should be noted
that response to a perceived predator does not necessarily invoke
flight (Ford and Reeves, 2008), and whether individuals are solitary or
in groups may influence the response.
Behavioral disturbance can also impact marine mammals in more
subtle ways. Increased vigilance may result in costs related to
diversion of focus and attention (i.e., when a response consists of
increased vigilance, it may come at the cost of decreased attention to
other critical behaviors such as foraging or resting). These effects
have generally not been demonstrated for marine mammals, but studies
involving fishes and terrestrial animals have shown that increased
vigilance may substantially reduce feeding rates (e.g., Beauchamp and
Livoreil, 1997; Fritz et al., 2002; Purser and Radford, 2011). In
addition, chronic disturbance can cause population declines through
reduction of fitness (e.g., decline in body condition) and subsequent
reduction in reproductive success, survival, or both (e.g., Harrington
and Veitch, 1992; Daan et al., 1996; Bradshaw et al., 1998). However,
Ridgway et al. (2006) reported that increased vigilance in bottlenose
dolphins exposed to sound over a 5-day period did not cause any sleep
deprivation or stress effects.
In 2015 and 2016, the Alaska Department of Transportation and
Public Facilities documented observations of marine mammals during
construction activities (i.e., pile driving and DTH) at the Kodiak
Ferry Dock (see 80 FR 60636, October 7, 2015) across 110 monitoring
days. In the marine mammal monitoring report for that project, 1,281
Steller sea lions were observed within the estimated Level B harassment
zone during pile driving or drilling. Of these, 19 individuals
demonstrated an alert behavior, seven were fleeing, and 19 swam away
from the project site. All other animals (98 percent) were engaged in
activities such as milling, foraging, or fighting and did not change
their behavior. In addition, two sea lions approached within 20 m of
active vibratory pile driving activities. Three harbor seals were
observed within the disturbance zone during pile driving activities;
none of them displayed disturbance behaviors. Fifteen killer whales and
3 harbor porpoises were also observed within the estimated Level B
harassment zone during pile driving. The killer whales were travelling
or milling while all harbor porpoises were travelling. No signs of
disturbance were noted for either of these species. Given the
similarities in activities and habitat and the fact the same species
are involved, we expect similar behavioral responses of marine mammals
to the USCG's specified activity. That is, disturbance, if any, is
likely to be temporary and localized (e.g., small area movements).
Stress responses--An animal's perception of a threat may be
sufficient to trigger stress responses consisting of some combination
of behavioral responses, autonomic nervous system responses,
neuroendocrine responses, or immune responses (e.g., Seyle, 1950;
Moberg, 2000). In many cases, an animal's first and sometimes most
economical (in terms of energetic costs) response is behavioral
avoidance of the potential stressor. Autonomic nervous system responses
to stress typically involve changes in heart rate, blood pressure, and
gastrointestinal activity. These responses have a relatively short
duration and may or may not have a significant long-term effect on an
animal's fitness.
Neuroendocrine stress responses often involve the hypothalamus-
pituitary-adrenal system. Virtually all neuroendocrine functions that
are affected by stress--including immune competence, reproduction,
metabolism, and behavior--are regulated by pituitary hormones. Stress-
induced changes in the secretion of pituitary hormones have been
implicated in failed reproduction, altered metabolism, reduced immune
competence, and behavioral disturbance (e.g., Moberg, 1987; Blecha,
2000). Increases in the circulation of glucocorticoids are also equated
with stress (Romano et al., 2004).
The primary distinction between stress (which is adaptive and does
not normally place an animal at risk) and ``distress'' is the cost of
the response. During a stress response, an animal uses glycogen stores
that can be quickly replenished once the stress is alleviated. In such
circumstances, the cost of the stress response would not pose serious
fitness consequences. However, when an animal does not have sufficient
energy reserves to satisfy the energetic costs of a stress response,
energy resources must be diverted from other functions. This state of
distress will last until the animal replenishes its
[[Page 12216]]
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, 2003), however
distress is an unlikely result of this project based on observations of
marine mammals during previous, similar projects in the area.
Auditory Masking--Since many marine mammals rely on sound to find
prey, moderate social interactions, and facilitate mating (Tyack,
2008), noise from anthropogenic sound sources can interfere with these
functions, but only if the noise spectrum overlaps with the hearing
sensitivity of the receiving marine mammal (Southall et al., 2007;
Clark et al., 2009; Hatch et al., 2012). Chronic exposure to excessive,
though not high-intensity, noise could cause masking at particular
frequencies for marine mammals that utilize sound for vital biological
functions (Clark et al., 2009). Acoustic masking is when other noises
such as from human sources interfere with an animal's ability to
detect, recognize, or discriminate between acoustic signals of interest
(e.g., those used for intraspecific communication and social
interactions, prey detection, predator avoidance, navigation)
(Richardson et al., 1995; Erbe et al., 2016). Therefore, under certain
circumstances, marine mammals whose acoustical sensors or environment
are being severely masked could also be impaired from maximizing their
performance fitness in survival and reproduction. The ability of a
noise source to mask biologically important sounds depends on the
characteristics of both the noise source and the signal of interest
(e.g., signal-to-noise ratio, temporal variability, direction), in
relation to each other and to an animal's hearing abilities (e.g.,
sensitivity, frequency range, critical ratios, frequency
discrimination, directional discrimination, age or TTS hearing loss),
and existing ambient noise and propagation conditions (Hotchkin and
Parks, 2013).
Under certain circumstances, marine mammals experiencing
significant masking could also be impaired from maximizing their
performance fitness in survival and reproduction. Therefore, when the
coincident (masking) sound is human-made, it may be considered
harassment when disrupting or altering critical behaviors. It is
important to distinguish TTS and PTS, which persist after the sound
exposure, from masking, which occurs during the sound exposure. Because
masking (without resulting in TS) is not associated with abnormal
physiological function, it is not considered a physiological effect,
but rather a potential behavioral effect (though not necessarily one
that would be associated with harassment).
The frequency range of the potentially masking sound is important
in determining any potential behavioral impacts. For example, low-
frequency signals may have less effect on high-frequency echolocation
sounds produced by odontocetes but are more likely to affect detection
of mysticete communication calls and other potentially important
natural sounds such as those produced by surf and some prey species.
The masking of communication signals by anthropogenic noise may be
considered as a reduction in the communication space of animals (e.g.,
Clark et al., 2009) and may result in energetic or other costs as
animals change their vocalization behavior (e.g., Miller et al., 2000;
Foote et al., 2004; Parks et al., 2007; Di Iorio and Clark, 2010; Holt
et al., 2009). Masking can be reduced in situations where the signal
and noise come from different directions (Richardson et al., 1995),
through amplitude modulation of the signal, or through other
compensatory behaviors (Hotchkin and Parks, 2013). Masking can be
tested directly in captive species (e.g., Erbe, 2008), but in wild
populations it must be either modeled or inferred from evidence of
masking compensation. There are few studies addressing real-world
masking sounds likely to be experienced by marine mammals in the wild
(e.g., Branstetter et al., 2013).
Marine mammals at or near the proposed USCG project site may be
exposed to anthropogenic noise which may be a source of masking.
Vocalization changes may result from a need to compete with an increase
in background noise and include increasing the source level, modifying
the frequency, increasing the call repetition rate of vocalizations, or
ceasing to vocalize in the presence of increased noise (Hotchkin and
Parks, 2013). For example, in response to loud noise, beluga whales may
shift the frequency of their echolocation clicks to prevent masking by
anthropogenic noise (Tyack, 2000; Eickmeier and Vallarta, 2022).
Masking is more likely to occur in the presence of broadband,
relatively continuous noise sources such as vibratory pile driving.
Energy distribution of pile driving covers a broad frequency spectrum,
and sound from pile driving would be within the audible range of
pinnipeds and cetaceans present in the proposed action area. While some
construction during the USCG's activities may mask some acoustic
signals that are relevant to the daily behavior of marine mammals, the
short-term duration and limited areas affected make it very unlikely
that the fitness of individual marine mammals would be impacted.
Airborne Acoustic Effects--Airborne noise would primarily be an
issue for pinnipeds that are swimming or hauled out near the project
site within the range of noise levels elevated above the acoustic
criteria. We recognize that pinnipeds in the water could be exposed to
airborne sound that may result in behavioral harassment when looking
with their heads above water. Most likely, airborne sound would cause
behavioral responses similar to those discussed above in relation to
underwater sound. For instance, anthropogenic sound could cause hauled-
out pinnipeds to exhibit changes in their normal behavior, such as
reduction in vocalizations, or cause them to temporarily abandon the
area and move further from the source. However, these animals would
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. Cetaceans are
not expected to be exposed to airborne sounds that would
[[Page 12217]]
result in harassment as defined under the MMPA.
Marine Mammal Habitat Effects
The USCG's proposed construction activities could have localized,
temporary impacts on marine mammal habitat and their prey by increasing
in-water SPLs and slightly decreasing water quality. Increased noise
levels may affect acoustic habitat (see Masking) and adversely affect
marine mammal prey in the vicinity of the project area (see discussion
below). During vibratory and impact pile driving and DTH, elevated
levels of underwater noise would ensonify a portion of Womens Bay,
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. In-water pile driving 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 the area where piles and vibroflots are
installed or removed. 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 sediments of the project site would
settle out rapidly when disturbed. Cetaceans are not expected to be
close enough to the pile driving areas to experience effects of
turbidity, and any pinnipeds could avoid localized areas of turbidity.
In-water Construction Effects on Potential Foraging Habitat--The
proposed activities would not result in permanent impacts to habitats
used directly by marine mammals. The areas likely impacted by the
proposed action are relatively small compared to the total available
habitat in the Gulf of Alaska. The total seafloor area affected by
piling activities is small compared to the vast foraging areas
available to marine mammals at either location. At best, the areas
impacted provide marginal foraging habitat for marine mammals and
fishes. Furthermore, pile driving at the project locations would not
obstruct movements or migration of marine mammals.
In-water Construction Effects on Potential Prey--Sound may affect
marine mammals through impacts on the abundance, behavior, or
distribution of prey species (e.g., crustaceans, cephalopods, fish,
zooplankton). Marine mammal prey varies by species, season, and
location and, for some, is not well documented. Here, we describe
studies regarding the effects of noise on known marine mammal prey.
Fish utilize the soundscape and components of sound in their
environment to perform important functions such as foraging, predator
avoidance, mating, and spawning (e.g., Zelick et al., 1999; Fay, 2009).
Depending on their hearing anatomy and peripheral sensory structures,
which vary among species, fishes hear sounds using pressure and
particle motion sensitivity capabilities and detect the motion of
surrounding water (Fay et al., 2008). The potential effects of noise on
fishes depends on the overlapping frequency range, distance from the
sound source, water depth of exposure, and species-specific hearing
sensitivity, anatomy, and physiology. Key impacts to fishes may include
behavioral responses, hearing damage, barotrauma (pressure-related
injuries), and mortality.
Fish react to sounds which are especially strong and/or
intermittent low-frequency sounds, and behavioral responses such as
flight or avoidance are the most likely effects. Short duration, sharp
sounds can cause overt or subtle changes in fish behavior and local
distribution. The reaction of fish to noise depends on the
physiological state of the fish, past exposures, motivation (e.g.,
feeding, spawning, migration), and other environmental factors.
Hastings and Popper (2005) identified several studies that suggest fish
may relocate to avoid certain areas of sound energy. Additional studies
have documented effects of pile driving on fish, although several are
based on studies in support of large, multiyear bridge construction
projects (e.g., Scholik and Yan, 2001, 2002; Popper and Hastings,
2009). Several studies have demonstrated that impulse sounds might
affect the distribution and behavior of some fishes, potentially
impacting foraging opportunities or increasing energetic costs (e.g.,
Fewtrell and McCauley, 2012; Pearson et al., 1992; Skalski et al.,
1992; Santulli et al., 1999; Paxton et al., 2017). However, some
studies have shown no or slight reaction to impulse sounds (e.g., Pena
et al., 2013; Wardle et al., 2001; Jorgenson and Gyselman, 2009; Cott
et al., 2012). More commonly, though, the impacts of noise on fish are
temporary.
SPLs of sufficient strength have been known to cause AUD INJ, non-
AUD INJ, and mortality to fish. However, in most fish species, hair
cells in the ear continuously regenerate and loss of auditory function
likely is restored when damaged cells are replaced with new cells.
Halvorsen et al. (2012a) showed that a TTS of 4-6 dB was recoverable
within 24 hours for one species. Impacts would be most severe when the
individual fish is close to the source and when the duration of
exposure is long. Injury caused by barotrauma can range from slight to
severe and can cause death, and is most likely for fish with swim
bladders. Barotrauma injuries have been documented during controlled
exposure to impact pile driving (Halvorsen et al., 2012b; Casper et
al., 2013).
In year 1, the greatest potential impact to fishes during
construction would occur during impact pile installation of 24-in and
42-in steel pipe piles, and 24-in precast square concrete, which is
estimated to occur on up to 44 days for a maximum of 14,400 strikes per
day, and DTH installation of 19-42-inch steel piles, which is estimated
to occur up to 55 days for a maximum of 180,000 strikes per day. In
year 2, the greatest potential impact to fishes during construction
would occur during impact pile installation of 24-in through 42-in
steel pipe piles, which is estimated to occur on up to 17 days for a
maximum of 14,400 strikes per day, and DTH installation of 19-24 inch
steel piles, which is estimated to occur up to 24 days for a maximum of
180,000 strikes per day. In-water construction activities would only
occur during daylight hours, allowing fish to forage and transit the
project area in the evening. Vibratory pile driving would possibly
elicit behavioral reactions from fishes such as temporary avoidance of
the area but is unlikely to cause injuries to fishes or have persistent
effects on local fish populations.
The most likely impact to fishes from pile driving and DTH
activities 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 (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
area would be affected for short periods of time, and the potential for
effects to fish would be temporary and
[[Page 12218]]
limited to the duration of sound-generating activities.
In summary, given the short daily duration of sound associated with
individual pile driving and DTH, and the relatively small areas being
affected, pile driving and DTH activities associated with the proposed
action are not likely to have a permanent adverse effect on any fish
habitat, or populations of fish species. Any behavioral avoidance by
fish of the disturbed area would still leave significantly large areas
of fish and marine mammal foraging habitat in the nearby vicinity.
Thus, we conclude that impacts of the specified activity are not likely
to have more than short-term adverse effects on any prey habitat or
populations of prey species. Further, any impacts to marine mammal
habitat are not expected to result in significant 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).
Authorized takes would primarily be by Level B harassment, as use
of the acoustic sources (i.e., vibratory and impact pile driving, DTH)
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 very high frequency
species, phocids, and otariids, because predicted AUD INJ zones are
larger than are observable. AUD INJ is unlikely to occur for high-
frequency species and mysticetes. The proposed mitigation and
monitoring measures are expected to minimize the severity of the taking
to the extent practicable.
As described previously, no serious injury or mortality is
anticipated or proposed to be authorized for this activity. Below we
describe how the proposed take numbers are estimated.
For acoustic impacts, generally speaking, we estimate take by
considering: (1) acoustic criteria above which NMFS believes the best
available science indicates marine mammals will be behaviorally
harassed or incur some degree of injury; (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). We note that the criteria for AUD INJ, as well as
the names of two hearing groups, have been recently updated (NMFS,
2024) as reflected below in the Level A harassment section.
Level B Harassment--Though significantly driven by received level,
the onset of behavioral disturbance from anthropogenic noise exposure
is also informed to varying degrees by other factors related to the
source or exposure context (e.g., frequency, predictability, duty
cycle, duration of the exposure, signal-to-noise ratio, distance to the
source), the environment (e.g., bathymetry, other noises in the area,
predators in the area), and the receiving animals (hearing, motivation,
experience, demography, life stage, depth) and can be difficult to
predict (e.g., Southall et al., 2007, 2021, Ellison et al., 2012).
Based on what the available science indicates and the practical need to
use a threshold based on a metric that is both predictable and
measurable for most activities, NMFS typically uses a generalized
acoustic threshold based on received level to estimate the onset of
behavioral harassment. NMFS generally predicts that marine mammals are
likely to be behaviorally harassed in a manner considered to be Level B
harassment when exposed to underwater anthropogenic noise above root-
mean-squared pressure received levels (RMS SPL) of 120 dB (referenced
to 1 (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.
USCG's proposed activity includes the use of continuous (vibratory
pile driving and DTH) and impulsive (impact pile driving and DTH)
sources, and therefore the RMS SPL thresholds of 120 AND/OR 160 dB re 1
[mu]Pa are applicable.
Level A Harassment--NMFS' 2024 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). USCG's proposed activity includes the use
of impulsive (impact pile driving and DTH) and non-impulsive (vibratory
pile driving and DTH) sources.
The 2024 Updated Technical Guidance criteria include both updated
thresholds and updated weighting functions for each hearing group.
These thresholds criteria thresholds are provided in the table below.
The references, analysis, and methodology used in the development of
the criteria thresholds, as well as the detailed description of the
updated weighting
[[Page 12219]]
functions, are described in NMFS' 202418 Updated Technical Guidance,
which may be accessed at: <a href="https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-acoustic-technical-guidance">https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-acoustic-technical-guidance</a>.
Table 5--Thresholds Identifying the Onset of AUD INJ Based on 2024 Technical Guidance
----------------------------------------------------------------------------------------------------------------
AUD INJ onset thresholds * (received level)
Hearing group -------------------------------------------------------------------------
Impulsive Non-impulsive
----------------------------------------------------------------------------------------------------------------
Low-Frequency (LF) Cetaceans.......... Cell 1: L0-pk,flat: 222 Cell 2: LE,LF,24h: 197 dB.
dB; LE,LF,24h: 183 dB.
High-Frequency (HF) Cetaceans......... Cell 3: L0-pk,flat: 230 Cell 4: LE,HF,24h: 201 dB.
dB; LE,HF,24h: 193 dB.
Very High-Frequency (VHF) Cetaceans... Cell 5: L0-pk,flat: 202 Cell 6: LE,VHF,24h: 181 dB.
dB; LE,VHF,24h: 159 dB.
Phocid Pinnipeds (PW) (Underwater).... Cell 7: L0-pk.flat: 223 Cell 8: LE,PW,24h: 195 dB.
dB; LE,PW,24h: 183 dB.
Otariid Pinnipeds (OW) (Underwater)... Cell 9: L0-pk,flat: 230 Cell 10: LE,OW,24h: 199 dB.
dB; LE,OW,24h: 185 dB.
----------------------------------------------------------------------------------------------------------------
* Dual metric thresholds for impulsive sounds: Use whichever results in the largest isopleth for calculating AUD
INJ onset. If a non-impulsive sound has the potential of exceeding the peak sound pressure level thresholds
associated with impulsive sounds, these thresholds are recommended for consideration.
Note: Peak sound pressure level (L0-pk) has a reference value of 1 [mu]Pa, and weighted cumulative sound
exposure level (LE,) has a reference value of 1[mu]Pa\2\s. In this table, thresholds 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 (i.e., 7 Hz to 165 kHz). The subscript associated with cumulative sound
exposure level thresholds 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 thresholds 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 thresholds will be exceeded.
Ensonified Area
Here, we describe operational and environmental parameters of the
activity that are used in estimating the area ensonified above the
acoustic thresholds, including source levels and transmission loss
coefficient.
The sound field in the project area is the existing background
noise plus additional construction noise from the proposed project.
Marine mammals are expected to be affected via sound generated by the
primary components of the project (i.e., vibratory pile driving and
removal, impact pile driving, and DTH).
The project includes vibratory pile installation and removal,
impact pile driving, and DTH. Source levels for these activities are
based on reviews of measurements of the same or similar types and
dimensions of pile available in the literature. Source levels for each
pile size and activity each year are presented in tables 6 and 7.
Source levels for vibratory installation and removal of piles of the
same diameter are assumed to be the same.
Table 6--Year 1 Estimates of Mean Underwater Sound Levels * Generated During Vibratory, Impact, and DTH Pile
Installation and Vibratory Pile Removal
----------------------------------------------------------------------------------------------------------------
Method Pile type Pile size dB RMS dB peak dB SEL Reference
----------------------------------------------------------------------------------------------------------------
Vibratory installation and Timber........... 14 160 N/A N/A Greenbusch 2018.
extraction.
24 160 N/A N/A Greenbusch 2018.
Steel Pipe....... 12 155 N/A N/A CalTrans 2015.
14 154 N/A N/A CalTrans 2020.
24 153 N/A N/A CalTrans 2020.
36 170 N/A N/A CalTrans 2015.
42 169 N/A N/A Illingworth and
Rodkin 2019.
Steel Pipe filled 24 163 N/A N/A NAVFAC SW 2022.
with Concrete.
Precast square 24 163 N/A N/A NAVFAC SW 2022.
concrete.
Stone column via 30 159 N/A N/A CalTrans 2020.
Vibroflot.
Impact........................ Steel Pipe....... 24 190 203 177 CalTrans 2015.
42 192 213 179 CalTrans 2020.
Precast Square ** 24 176 195 164 CalTrans
Concrete. (measured at
17.5 m).
DTH........................... Steel Pipe....... 19-24 167 184 159 Heyvaert & Reyff
2021.
25-42 174 194 164 Denes et al.,
2019; Heyvaert,
2019; Reyff,
2020.
----------------------------------------------------------------------------------------------------------------
Note: dB peak = peak sound level; rms = root mean square; SEL = sound exposure level.
* All sound levels are referenced at 10 m unless otherwise indicated.
** Sound levels for impact installation of 24-inch precast square concrete are measured at 17.5 m.
Table 7--Year 2 Estimates of Mean Underwater Sound Levels * Generated During Vibratory, Impact, and DTH Pile
Installation and Vibratory Pile Removal
----------------------------------------------------------------------------------------------------------------
Method Pile type Pile size dB RMS dB peak dB SEL Reference
----------------------------------------------------------------------------------------------------------------
Vibratory installation and Steel Pipe....... 24 153 N/A N/A CalTrans 2020.
extraction.
30 159 N/A N/A CalTrans 2020.
36 170 N/A N/A CalTrans 2015.
42 169 N/A N/A Illingworth and
Rodkin 2019.
Impact........................ Steel Pipe....... 24 190 203 177 CalTrans 2015.
30 190 210 177 CalTrans 2020.
36 193 210 183 CalTrans 2020.
42 192 213 179 CalTrans 2020.
DTH........................... Steel Pipe....... 19-24 167 184 159 Heyvaert & Reyff
2021.
[[Page 12220]]
25-42 174 194 164 Denes et al.,
2019; Heyvaert,
2019; Reyff,
2020.
----------------------------------------------------------------------------------------------------------------
Note: dB peak = peak sound level; rms = root mean square; SEL = sound exposure level.
* All sound levels are referenced at 10 m.
DTH systems have both continuous, non-impulsive, and impulsive
components as discussed in the Description of Sound Sources section
above. When evaluating Level B harassment, NMFS recommends treating DTH
as a continuous source and applying RMS SPL thresholds of 120 dB re 1
[mu]Pa. When evaluating Level A harassment, NMFS recommends treating
DTH as an impulsive source. NMFS (2022) guidance on DTH systems
(<a href="https://media.fisheries.noaa.gov/2022-11/PUBLIC%20DTH%20Basic%20Guidance_November%202022.pdf">https://media.fisheries.noaa.gov/2022-11/PUBLIC%20DTH%20Basic%20Guidance_November%202022.pdf</a>) recommends source
levels for DTH systems; NMFS has applied those levels in our analysis
(see tables 6 and 7 for NMFS' proposed source levels).
TL is the decrease in acoustic intensity as an acoustic pressure
wave propagates out from a source. TL parameters vary with frequency,
temperature, sea conditions, current, source and receiver depth, water
depth, water chemistry, and bottom composition and topography. The
general formula for underwater TL is:
TL = B x Log10 (R<INF>1</INF>/R<INF>2</INF>),
Where:
TL = transmission loss in dB
B = transmission loss coefficient
R<INF>1</INF> = the distance of the modeled SPL from the driven
pile, and
R<INF>2</INF> = the distance from the driven pile of the initial
measurement
Absent site-specific acoustical monitoring with differing measured
TL, a practical spreading value of 15 is used as the TL coefficient in
the above formula. Site-specific TL data for the Womens Bay are not
available; therefore, the default coefficient of 15 is used to
determine the distances to the Level A harassment and Level B
harassment thresholds.
The ensonified area associated with Level A harassment is more
technically challenging to predict due to the need to account for a
duration component. Therefore, NMFS developed an optional User
Spreadsheet tool to accompany the 2024 Updated Technical Guidance that
can be used to relatively simply predict an isopleth distance for use
in conjunction with marine mammal density or occurrence to help predict
potential takes. We note that because of some of the assumptions
included in the methods underlying this optional tool, we anticipate
that the resulting isopleth estimates are typically going to be
overestimates of some degree, which may result in an overestimate of
potential take by Level A harassment. However, this optional tool
offers the best way to estimate isopleth distances when more
sophisticated modeling methods are not available or practical. For
stationary sources such as pile driving and DTH, the optional User
Spreadsheet tool predicts the distance at which, if a marine mammal
remained at that distance for the duration of the activity, it would be
expected to incur AUD INJ, which includes but is not limited to PTS.
Inputs used in the optional User Spreadsheet tool (e.g., number of
piles per day, duration, and/or strikes per pile), are presented in
tables 1, 2, the sound levels are presented in tables 6 and 7, and the
resulting estimated isopleths and total ensonified areas are reported
below in tables 8 and 9.
Table 8--Projected Distances to Level A and Level B Harassment Isopleths (m) and Associated Areas \1\ (km\2\) by Marine Mammal Hearing Group--Year 1
Activities
--------------------------------------------------------------------------------------------------------------------------------------------------------
Level B
Pile type Pile size LF HF VHF PW OW harassment
--------------------------------------------------------------------------------------------------------------------------------------------------------
Vibratory Installation and Extraction:
Timber................................. 14 17.7 6.8 14.4 22.7 7.6 \2\ 4,642 (7.52)
24 17.7 6.8 14.4 22.7 7.6 \2\ 4,642 (7.52)
Steel.................................. 12 18.2 3.1 6.7 10.5 3.5 2,154
14 7.0 2.7 5.7 9.0 3.0 1,848
24 4.3 1.6 3.5 5.5 1.9 1,585
36 58.3 22.4 47.6 75.0 25.3 \2\ 21,544 (7.52)
42 50.0 19.2 40.8 64.3 21.7 \2\ 18,478 (7.52)
Steel/Concrete......................... 24 28 10.7 22.9 36.0 12.1 \2\ 7,356 (7.52)
Precast Concrete....................... 24 19.9 7.6 16.3 25.6 8.6 \2\ 7,356 (7.52)
Vibroflot.............................. 30 26 10 21.2 33.5 11.3 3,981
Impact Pile Driving:
Steel.................................. 24 1,935.4 246.9 2,995.1 1,719.3 640.9 (1.01) 1,000
42 3,187.1 406.6 4,932.1 2,831.3 1,055 (1.32) 1,359
Precast Concrete....................... 24 557.7 71.2 863.1 495.5 184.7 204
Down-the-hole Drilling:
Steel.................................. 19-24 796.8 101.7 1,233.0 (1.49) 707.8 (1.07) 263.8 (0.32) \2\ 13,594 (7.52)
25-42 1,716.6 219.0 2,656.5 (4.17) 1,525.0 (1.83) 568.4 (0.91) \2\ 39,811 (7.52)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Abbreviations: LF = low-frequency cetaceans, HF = high-frequency cetaceans, VHF = very high-frequency cetaceans, PW = phocid pinnipeds in water, OW =
otariid pinnipeds in water.
\1\ Only harassment areas used in take estimate calculations are presented.
\2\ Total harassment areas are the same despite having varying calculated isopleths because the maximum distance is truncated by the other side of
Womens Bay.
[[Page 12221]]
Table 9--Projected Distances to Level A and Level B Harassment Isopleths (m) and Associated Areas \1\ (km\2\) by Marine Mammal Hearing Group--Year 2
Activities
--------------------------------------------------------------------------------------------------------------------------------------------------------
Level B
Pile type Pile size LF HF VHF PW OW harassment
--------------------------------------------------------------------------------------------------------------------------------------------------------
Vibratory Installation and Extraction:
Steel.................................. 24 4.3 1.6 3.5 5.5 1.9 1,585
30 10.8 4.1 8.8 13.9 4.7 3,981
36 58.3 22.4 47.6 75.0 25.3 \2\ 21,544 (7.52)
42 50.0 19.2 40.8 64.3 21.7 \2\ 18,478 (7.52)
Impact Pile Driving:
Steel.................................. 24 1,935.4 246.9 2,995.1 1,719.3 640.9 (1.01) 1,000
30 1,935.4 246.9 2,995.1 1,719.3 640.9 (1.01) 1,000
36 3,710.0 473.4 \1\ 5,741.3 3,295.9 1,228.6 (1.49) 1,585
42 3,187.1 406.6 \1\ 4,932.1 2,831.3 1,055 (1.32) 1,359
Down-the-hole Drilling:
Steel.................................. 19-24 796.8 101.7 1,233.0 (1.49) 707.8 (1.07) 263.8 (0.32) \2\ 13,594 (7.52)
25-42 1,716.6 219.0 2,656.5 (4.17) 1,525.0 (1.83) 568.4 (0.91) \2\ 39,811 (7.52)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Abbreviations: LF = low-frequency cetaceans, HF = high-frequency cetaceans, VHF = very high-frequency cetaceans, PW = phocid pinnipeds in water, OW =
otariid pinnipeds in water.
\1\ Only harassment areas used in take estimate calculations are presented.
\2\ Total harassment areas are the same despite having varying calculated isopleths because the maximum distance is truncated by the other side of
Womens Bay.
Level A harassment zones are typically smaller than Level B
harassment zones. However, in rare cases such as during impact pile
driving of 24, 30, 36 and 42-inch steel piles and 24-inch precast
concrete piles, the calculated Level A harassment isopleth is greater
than the calculated Level B harassment isopleth for low frequency
cetaceans, very high-frequency cetaceans, and phocids (tables 8 and 9).
Calculation of Level A harassment isopleths include a duration
component, which in the case of impact pile driving, is estimated
through the total number of daily strikes and the associated pulse
duration. For a stationary sound source such as impact pile driving, we
assume here that an animal is exposed to all of the strikes expected
within a 24-hour period. Calculation of a Level B harassment zone does
not include a duration component. Depending on the duration included in
the calculation, the calculated Level A harassment isopleths can be
larger than the calculated Level B harassment isopleth for the same
activity. This is the case for this project for low frequency
cetaceans, very high frequency cetaceans, and phocids during impact
pile driving of 24 and 42-inch steel piles and 24-inch precast concrete
piles in year 1, and during impact pile driving of 24, 30, 36, and 42-
inch steel piles in year 2.
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. Additionally, we describe how the
occurrence information is synthesized to produce a quantitative
estimate of the take that is reasonably likely to occur and proposed
for authorization. Available information regarding marine mammal
occurrence in the vicinity of the project area includes site-specific
and nearby survey information and knowledge from local tribes. Data
sources consulted included: (1) Anecdotal input from the Sunaq Tribe of
Kodiak's Natural Resources Director (Van Daele, personal communication,
2024), (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 9 km northeast of Womens Bay (ABR Inc., 2016), (3) PSO
monitoring completed in Womens Bay on 12 days in March 2018 during the
USCG Cargo Dock Repair project (USCG 2018), (4) Surveys described in
Cetaceans of Southeast Alaska: Distribution and Seasonal Occurrence
(group size estimates for Dall's porpoise) (Dalheim et al., 2009), and
(5) Alaska Wildlife Notebook Series (group size estimates for low-
frequency cetaceans) (Frost and Karpovich, 2008; Clark, 2008; Guerrero,
2008).
In its initial application, the USCG estimated take using data
sources 2, 4, and the U.S. Navy's Marine Species Density Database. NMFS
recommended the inclusion of the data sources listed above and the
exclusion of the density estimates given that they were calculated for
offshore areas; USCG concurred, and updated its application to reflect
NMFS' recommended method. Therefore, to estimate take, NMFS referred to
the sets listed above to estimate a daily occurrence probability in
which groups per day and group size are estimated for each species and
multiplied by the number of days of each type of pile driving activity.
For species that are unlikely to occur in the project area, but for
which there is some potential (low frequency cetaceans and Pacific
white-sided dolphin), NMFS predicts that one group of each species may
occur in the project area during each project year. NMFS used the
following equation to estimate take by Level B harassment for all
species other than low-frequency cetaceans and Pacific white-sided
dolphin:
Take by Level B harassment = group size x groups per day x days of pile
driving activities in which the Level B harassment isopleths are larger
than the Level A harassment isopleths
For activities where the Level A harassment isopleth is larger than
the Level B harassment isopleth for a given hearing group, NMFS
conservatively assumes that all take from that activity of that hearing
group would be by Level A harassment, as described further below.
The USCG proposes to implement shutdown zones that meet or exceed
the Level A harassment isopleths: (1) for all hearing groups during all
vibratory pile driving activities; (2) for low and high-frequency
cetaceans during impact pile driving and DTH activities (3) for
otariids, during impact installation of 24-inch pre-cast concrete and
DTH installation of 19-24-inch Steel piles. For other hearing groups
and activity combinations, the Level A harassment zone would exceed the
shutdown zone, as described in more detail below.
For activities and hearing groups where the Level A harassment
isopleth is larger than the Level B harassment isopleth, NMFS used the
following equation to estimate take by Level A harassment:
Group size x groups per day x days of pile driving activities in which
the Level A harassment isopleth is larger than the Level B isopleth
[[Page 12222]]
For very-high frequency cetaceans and phocids, the calculated Level
A harassment zones exceed the proposed shutdown zones during impact
installation of all piles. For otariids, the calculated Level A
harassment zones exceed the proposed shutdown zones during impact
installation of all piles except for 24-inch pre-cast concrete and DTH
of 19-24-inch steel.
For activities and hearing groups where the Level A harassment
isopleth is larger than the shutdown zone but smaller than the Level B
harassment zone, we proportionally compared, by hearing group, the
portion of the largest Level A harassment area (km\2\) that exceeds the
planned shutdown zone area (km\2\) to the area (km\2\) of the Level B
harassment zone for that activity and pile type. NMFS then multiplied
this proportion by the group size, daily sightings, and number of
construction days, according to the following equation:
Take by Level A harassment = Level A harassment area* (km\2\)/Level B
harassment area (km\2\) x group size x groups per day x days of pile
driving.
* The Level A harassment area refers to the Level A harassment
isopleth minus the proposed shutdown zone for that activity and hearing
group.
Gray Whale
Gray whales are solitary animals often traveling alone or in small
groups of three (Frost and Karpovich, 2008). They are rare in the
project area. Therefore, NMFS predicts that one group of three gray
whales could occur within the Level B harassment zone during each year
of the project and proposes to authorize three takes by Level B
harassment for gray whale in year 1 and three takes by Level B
harassment for gray whale in year 2.
Takes by Level A harassment for gray whale are not requested nor
are they proposed for authorization during either project year.
Fin Whale
Fin whale are typically observed in groups of 6 to 10 animals
(Clark, 2008a). They are rare in the project area. Therefore NMFS
predicts that one group of six fin whale could occur within the Level B
harassment zone across the project, each year, to account for the small
but unlikely possibility that this species could occur within the
project area. Therefore, NMFS proposes to authorize six takes by Level
B harassment for fin whale in year 1 and six takes by Level B
harassment for fin whale in year 2.
Takes by Level A harassment for fin whale are not requested nor are
they proposed for authorization either project year.
Humpback Whale
Humpback whale are often observed alone or in small groups that
persist for only a few hours (Zimmerman and Karpovich, 2008). They are
rare in the project area. Therefore NMFS predicts that one group of two
humpback whale could occur within the Level B harassment zone across
the project, each year, to account for the small but unlikely
possibility that this species could occur within the project area.
Therefore, NMFS proposes to authorize two takes by Level B harassment
for humpback whale (any stock) in year 1 and two takes by Level B
harassment for humpback whale (any stock) in year 2.
Takes by Level A harassment for humpback whale are not requested
nor are they proposed for authorization either project year.
Minke Whale
Minke whale are often observed in groups of two or three (Guerrero,
2008). While rare, it is possible that minke whale could occur within
the project area. Therefore, NMFS predicts that one group of two minke
whale could occur within the Level B harassment zone across the
project, each year, to account for the small but unlikely possibility
that this species could occur within the project area. Therefore, NMFS
proposes to authorize three takes by Level B harassment for minke whale
in year 1 and three takes by Level B harassment for minke whale in year
2.
Takes by Level A harassment for minke whale are not requested nor
are they proposed for authorization either project year.
Killer Whale
Based on the known occurrence of killer whale and confirmation of
sightings within the general vicinity of Womens Bay, it is likely that
both resident and transient killer whale would occur within the project
area. Based on local sightings, NMFS predicts one group of seven killer
whales could occur within the Level B harassment zone every 1
construction month (30 days). In year 1, for this species, the duration
of the construction for which the Level B zone is larger than the Level
A zone is 264 days (8.8 is the basic 30 day period that corresponds to
1 construction months). This results in 62 takes by Level B harassment
of killer whale (7 killer whale x 8.8 30-day periods) across any stock.
In year 2, for this species, the duration of the construction for
which the Level B zone is larger than the Level A zone is 76 days (2.5
is the basic 30 day period that corresponds to 1 construction months).
This results in 18 takes by Level B harassment of killer whale (7
killer whale x 2.5 30-day periods) across any stock.
Takes by Level A harassment for killer whale are not requested nor
are they proposed for authorization either project year.
Pacific White-Sided Dolphin
Pacific white-sided dolphin group sizes are usually between 10 and
100 animals. Due to the shallow, enclosed nature of Womens Bay it would
be a rare, though possible, occurrence for individuals to enter the
action area. Therefore, NMFS predicts that one group of 10 pacific
white-sided dolphin could occur within the Level B harassment zone
across the project, each year, to account for the small but unlikely
possibility that this species could occur within the project area.
Therefore, NMFS proposes to authorize 10 takes by Level B harassment
for pacific white-sided dolphin in year 1 and 3 takes by Level B
harassment for pacific white-sided dolphin in year 2.
Takes by Level A harassment for Pacific white-sided dolphin are not
requested nor are they proposed for authorization either project year.
Dall's Porpoise
Information regarding group size near Kodiak Island is limited;
however, studies conducted along the inland waters of southeast Alaska
indicate average group sizes ranged from 2.51 to 5.46 individuals
during surveys conducted from 1991 to 2007 (Dahlheim et al., 2009).
While there are no known sightings in Womens Bay, because Dall's
porpoise have been documented around Kodiak Island and have been known
to occur in nearshore habitats, NMFS predicts that one group of four
Dall's porpoise could occur within the Level B harassment zone every 1
construction month (30 days) each year.
In year 1, the duration of the construction for which the Level B
harassment zone is larger than the Level A harassment zone is 257 days
(8.6 is the basic 30 day period that corresponds to 1 construction
months). This results in 35 takes by Level B harassment of Dall's
porpoise (4 Dall's porpoise x 8.6 30-day periods).
During all DTH activities, the Level A harassment zone is larger
than the shutdown zone, but smaller than the Level B harassment zone.
As such it is possible that Dall's porpoise may enter
[[Page 12223]]
the Level A harassment zone and stay long enough to incur AUD INJ
before exiting. For DTH of 19-24-in steel piles, the ratio of the Level
A harassment area that exceeds the shutdown zone to the Level B
harassment area is 0.14. This activity is predicted to take place on 7
construction days (7 construction days / 30 days = 0.23 30-day
construction periods). For DTH of 24-42-in steel piles, the ratio of
the Level A harassment area that exceeds the shutdown zone to the Level
B harassment area is 0.50. This activity is predicted to take place on
48 construction days (48 construction days / 30 days = 1.6 30-day
construction periods). As such, 4 takes by Level A harassment are
proposed for authorization [(0.14 x 1 group x 4 Dall's porpoise x 0.23
30-day construction periods) + (0.5 x 1 group x 4 Dall's porpoises x
1.6 30-day construction periods) = 3.3 takes by Level A harassment].
During all impact pile driving, the Level A harassment zone is
larger than the Level B harassment zone. These activities are predicted
to take place on 44 construction days (44 construction days / 30 days =
1.5 30-day construction periods). Estimated take by Level A harassment
for these activities result in 2 based on 1 group x 4 Dall's porpoise x
1.5 30 day construction periods (1 x 4 x 1.5 = 6 takes by Level A
harassment).
Takes by Level B harassment were modified to deduct the proposed
amount of take by Level A harassment estimated in cases where the Level
A zone is smaller than the Level B zone (i.e., 35 total exposures-4
takes by Level A harassment estimated during DTH activities = 31 takes
by Level B harassment). Therefore, for Dall's porpoise, NMFS proposes
to authorize 10 takes by Level A harassment (4 takes + 6 takes) and 31
takes by Level B harassment, for a total of 41 takes in year 1.
In year 2, the duration of the construction for which the Level B
harassment zone is larger than the Level A harassment zone is 76 days
(2.5 is the basic 30 day period that corresponds to 1 construction
months). This results in 10 takes by Level B harassment of Dall's
porpoise (4 Dall's porpoise x 2.5 30-day periods).
During all DTH activities, the Level A harassment zone is larger
than the shutdown zone, but smaller than the Level B harassment zone.
As such it is possible that Dall's porpoise may enter the Level A
harassment zone and stay long enough to incur AUD INJ before exiting.
For DTH of 19-24-in steel piles, the ratio of the Level A harassment
area that exceeds the shutdown zone to the Level B harassment area is
0.14. This activity is predicted to take place on 6 construction days
(6 construction days / 30 days = 0.2 30-day construction periods). For
DTH of 24-42-in steel piles, the ratio of the Level A harassment area
that exceeds the shutdown zone to the Level B harassment area is 0.50.
This activity is predicted to take place on 18 construction days (18
construction days / 30 days = 0.6 30-day construction periods). As
such, two takes by Level A harassment are proposed for authorization
[(0.14 x 1 group x 4 Dall's porpoise x 0.2 30-day construction periods)
+ (0.5 x 1 group x 4 Dall's porpoises x 0.6 30-day construction
periods) = 1.3 takes by Level A harassment].
During all impact pile driving, the Level A harassment zone is
larger than the Level B harassment zone. These activities are predicted
to take place on 17 construction days (17 construction days / 30 days =
0.6 30-day construction periods). Estimated take by Level A harassment
for these activities result in three based on 1 group x 4 Dall's
porpoise x 0.6 30 day construction periods (1 x 4 x 0.6 = 2.4 takes by
Level A harassment).
Takes by Level B harassment were modified to deduct the proposed
amount of take by Level A harassment estimated in cases where the Level
A harassment zone is smaller than the Level B zone (i.e., 10 total
exposures-2 takes by Level A harassment estimated during DTH activities
= 8 takes by Level B harassment). Therefore, for Dall's porpoise, NMFS
proposes to authorize 5 takes by Level A harassment (2 takes + 3 takes)
and 8 takes by Level B harassment, for a total of 13 takes in year 1.
Harbor Porpoise
Harbor porpoises are known to frequent nearshore habitats,
including bays, and have been documented in bays near the project area
(Van Daele, 2024, personal communication; therefore, harbor porpoises
may intermittently enter the project area. Based on input from the
Sunaq tribe, NMFS predicts one group of six harbor porpoises could
occur within the Level B harassment zone every 1 construction month (30
days) each year (Van Deale, 2024, personal communication).
In year 1, the duration of the construction for which the Level B
zone is larger than the Level A zone is 257 days (8.6 is the basic 30
day period that corresponds to 1 construction months). This results in
52 takes by Level B harassment of harbor porpoise (6 harbor porpoise x
8.6 30-day periods).
During all DTH activities, the Level A harassment zone is larger
than the shutdown zone, but smaller than the Level B zone. As such it
is possible that harbor porpoise may enter the Level A harassment zone
and stay long enough to incur AUD INJ before exiting. For DTH of 19-24-
in steel piles, the ratio of the Level A harassment area that exceeds
the shutdown zone to the Level B harassment area is 0.14. This activity
is predicted to take place on 7 construction days (7 construction days
/ 30 days = 0.23 30-day construction periods). For DTH of 24-42-in
steel piles, the ratio of the Level A harassment area that exceeds the
shutdown zone to the Level B harassment area is 0.50. This activity is
predicted to take place on 48 construction days (48 construction days /
30 days = 1.6 30-day construction periods). As such, five takes by
Level A harassment are proposed for authorization [(0.14 x 1 group x 6
harbor porpoise x 0.23 30-day construction periods) + (0.5 x 1 group x
6 harbor porpoises x 1.6 30-day construction periods) = 5 takes by
Level A harassment].
During all impact pile driving, the Level A harassment zone is
larger than the Level B harassment zone. These activities are predicted
to take place on 44 construction days (44 construction days / 30 days =
1.5 30-day construction periods). Estimated take by Level A harassment
for these activities result in nine based on 1 group x 6 harbor
porpoise x 1.5 30 day construction periods (1 x 6 x 1.5 = 8.8 takes by
Level A harassment).
Takes by Level B harassment were modified to deduct the proposed
amount of take by Level A harassment estimated in cases where the Level
A harassment zone is smaller than the Level B harassment zone (i.e., 52
total exposures-5 takes by Level A harassment estimated during DTH
activities = 47 takes by Level B harassment). Therefore, for harbor
porpoise, NMFS proposes to authorize 14 takes by Level A harassment (5
takes + 9 takes) and 47 takes by Level B harassment, for a total of 61
takes in year 1.
In year 2, the duration of the construction for which the Level B
harassment zone is larger than the Level A harassment zone is 76 days
(2.5 is the basic 30 day period that corresponds to 1 construction
months). This results in 16 takes by Level B harassment of harbor
porpoise (6 harbor porpoise x 2.5 30-day periods).
[[Page 12224]]
During all DTH activities, the Level A harassment zone is larger
than the shutdown zone, but smaller than the Level B zone. As such it
is possible that Dall's porpoise may enter the Level A harassment zone
and stay long enough to incur AUD INJ before exiting. For DTH of 19-24-
in steel piles, the ratio of the Level A harassment area that exceeds
the shutdown zone to the Level B harassment area is 0.14. This activity
is predicted to take place on 6 construction days (6 construction days
/ 30 days = 0.2 30-day construction periods). For DTH of 24-42-in steel
piles, the ratio of the Level A harassment area that exceeds the
shutdown zone to the Level B harassment area is 0.50. This activity is
predicted to take place on 18 construction days (18 construction days /
30 days = 0.6 30-day construction periods). As such, two takes by Level
A harassment are proposed for authorization [(0.14 x 1 group x 6 harbor
porpoise x 0.2 30-day construction periods) + (0.5 x 1 group x 6 harbor
porpoise x 0.6 30-day construction periods) = 2.0 takes by Level A
harassment].
During all impact pile driving, the Level A harassment zone is
larger than the Level B harassment zone. These activities are predicted
to take place on 17 construction days (17 construction days / 30 days =
0.6 30-day construction periods). Estimated take by Level A harassment
for these activities result in four based on 1 group x 6 harbor
porpoise x 0.6 30 day construction periods (1 x 6 x 0.6 = 3.6 takes by
Level A harassment).
Takes by Level B harassment were modified to deduct the proposed
amount of take by Level A harassment estimated in cases where the Level
A zone is smaller than the Level B harassment zone (i.e., 16 total
exposures-2 takes by Level A harassment estimated during DTH activities
= 14 takes by Level B harassment). Therefore, for harbor porpoise, NMFS
proposes to authorize 6 takes by Level A harassment (2 takes + 4 takes)
and 14 takes by Level B harassment, for a total of 20 takes in year 2.
Northern Fur Seal
It is possible, though rare, that a northern fur seal could occur
within the project area. Therefore, NMFS predicts that one northern fur
seal could occur within the Level B harassment zone every 1
construction month (30 days) each year, to account for the small but
unlikely possibility that this species could occur within the project
area. In year 1, the duration of the construction for which the Level B
zone is larger than the Level A zone is 264 days (8.8 is the basic 30
day period that corresponds to 1 construction months). This results in
nine takes by Level B harassment of northern fur seal (1 northern fur
seal x 8.8 30-day periods). Because exposure estimates are low, and the
Level A harassment zones are larger than are likely observable during
impact pile driving and DTH of 24-42-inch steel piles, NMFS proposed to
authorize these nine takes by either Level A harassment or Level B
harassment.
In year 2, the duration of the construction for which the Level B
harassment zone is larger than the Level A harassment zone is 76 days
(2.5 is the basic 30 day period that corresponds to 1 construction
months). This results in three takes by Level B harassment of northern
fur seal (1 northern fur seal x 2.5 30-day periods). Because exposure
estimates are low, and the Level A harassment zones are larger than are
likely observable during impact pile driving and DTH of 24-42-inch
steel piles, NMFS proposed to authorize these three takes by either
Level A harassment or Level B harassment.
Steller Sea Lion
While data are limited, the Sunaq Tribe of Kodiak suggests that the
bottom topography of Womens Bay is not conducive to Steller sea lion
foraging, but it is possible that Steller sea lions will occur
intermittently in Womens Bay (Van Daele, 2024, personal communication).
Therefore, NMFS predicts that one group of two Steller sea lions could
occur within the Level B harassment zone every 2 construction weeks (14
days) each year.
In year 1, the duration of the construction for which the Level B
harassment zone is larger than the Level A harassment zone is 264 days
(18.9 is the basic 14 day period that corresponds to 2 construction
weeks). This results in 38 takes by Level B harassment of Steller sea
lion (2 Steller sea lion x 18.9 14-day periods).
During DTH of 25-42-inch steel piles and all impact pile driving
activities except for 24-inch pre-cast concrete, the Level A harassment
zone is larger than the shutdown zone, but smaller than the Level B
harassment zone. As such it is possible that Steller sea lions may
enter the Level A harassment zone and stay long enough to incur AUD INJ
before exiting. For DTH of 25-42-in steel piles, the ratio of the Level
A harassment area that exceeds the shutdown zone to the Level B
harassment area is 0.07. This activity is predicted to take place on 48
construction days (48 construction days / 14 days = 3.4 14-day
construction periods). For impact installation of 42-in steel, the
ratio of the Level A harassment area that exceeds the shutdown zone to
the Level B harassment area is 0.12. This activity is predicted to take
place on 32 construction days (32 construction days / 14 days = 2.3 14-
day construction periods). For impact installation of 24-in steel, the
ratio of the Level A harassment area that exceeds the shutdown zone to
the Level B harassment area is also 0.08. This activity is predicted to
take place on 5 construction days (5 construction days / 14 days = 0.4
14-day construction periods).
As such, two takes by Level A harassment is proposed for
authorization [(0.07 x 1 group x 2 Steller sea lion x 3.4 14-day
construction periods) + (0.12 x 1 group x 2 Steller sea lion x 2.3 14-
day construction periods) + 0.08 x 1 group x 2 Steller sea lion x 0.4
14-day construction periods = 1.08 takes by Level A harassment].
Takes by Level B harassment were modified to deduct the proposed
amount of take by Level A harassment estimated in cases where the Level
A zone is smaller than the Level B zone (i.e., 38 total exposures-2
takes by Level A harassment activities = 36 takes by Level B
harassment). Therefore, for Steller sea lion, NMFS proposes to
authorize 2 takes by Level A harassment and 36 takes by Level B
harassment, for a total of 38 takes in year 1.
In year 2, the duration of the construction for which the Level B
harassment zone is larger than the Level A harassment zone is 76 days
(5.4 is the basic 14 day period that corresponds to 2 construction
weeks). This results in 11 takes by Level B harassment of Steller sea
lion (2 Steller sea lion x 5.4 14-day periods).
During DTH of 25-42-inch steel piles and all impact pile driving
activities except for 24-inch pre-cast concrete, the Level A harassment
zone is larger than the shutdown zone, but smaller than the Level B
harassment zone. As such it is possible that Steller sea lion may enter
the Level A harassment zone and stay long enough to incur AUD INJ
before exiting. For DTH of 25-42-in steel piles, the ratio of the Level
A harassment area that exceeds the shutdown zone to the Level B
harassment area is 0.07. This activity is predicted to take place on 18
construction days (18 construction days / 14 days = 1.3 14-day
construction periods). For impact installation of 42-in steel, the
ratio of the Level A harassment area that exceeds the shutdown zone to
the Level B harassment area is 0.12. This activity is predicted to take
place on 5
[[Page 12225]]
construction days (5 construction days / 14 days = 0.4 14-day
construction periods). For impact installation of 36-in steel, the
ratio of the Level A harassment area that exceeds the shutdown zone to
the Level B harassment area is 0.14. This activity is predicted to take
place on 3 construction days (3 construction days / 14 days = 0.2 14-
day construction periods). For impact installation of 30-in steel, the
ratio of the Level A harassment area that exceeds the shutdown zone to
the Level B harassment area is 0.08. This activity is predicted to take
place on 5 construction days (5 construction days / 14 days = 0.4 14-
day construction periods). For impact installation of 24-in steel, the
ratio of the Level A harassment area that exceeds the shutdown zone to
the Level B harassment area is also 0.08. This activity is predicted to
take place on 4 construction days (4 construction days / 14 days = 0.3
14-day construction periods).
As such, one take by Level A harassment is proposed for
authorization [(0.07 x 1 group x 2 Steller sea lion x 1.3 14-day
construction periods) + (0.12 x 1 group x 2 Steller sea lion x 0.4 14-
day construction periods) + 0.14 x 1 group x 2 Steller sea lion x 0.2
14-day construction periods + (0.08 x 1 group x 2 Steller sea lion x
0.4 14-day construction periods) + (0.08 x 1 group x 2 Steller sea lion
x 0.3 14-day construction periods) = 0.43 takes by Level A harassment].
Takes by Level B harassment were modified to deduct the proposed
amount of take by Level A harassment estimated in cases where the Level
A harassment zone is smaller than the Level B harassment zone (i.e., 11
total exposures-1 take by Level A harassment activities = 10 takes by
Level B harassment). Therefore, for Steller sea lion, NMFS proposes to
authorize 1 take by Level A harassment and 10 takes by Level B
harassment, for a total of 11 takes in year 2.
Harbor Seal
Harbor seals are known to frequent nearshore habitats and have been
documented in large numbers in the project area. Based on local data,
NMFS predicts that one group of 24 harbor seal are could occur within
the Level B harassment zone every 1 construction week (7 days) each
year.
In year 1, the duration of the construction for which the Level B
harassment zone is larger than the Level A harassment zone is 257 days
(36.7 is the basic 7 day period that corresponds to 1 construction
week). This results in 882 takes by Level B harassment of harbor seal
(24 harbor seal x 36.7 7-day periods).
During all DTH activities, the Level A harassment zone is larger
than the shutdown zone, but smaller than the Level B harassment zone.
As such it is possible that harbor porpoise may enter the Level A
harassment zone and stay long enough to incur AUD INJ before exiting.
For DTH of 19-24-in steel piles, the ratio of the Level A harassment
area that exceeds the shutdown zone to the Level B harassment area is
0.09. This activity is predicted to take place on 7 construction days
(7 construction days / 7 days = 1 7-day construction periods). For DTH
of 24-42-in steel piles, the ratio of the Level A harassment area that
exceeds the shutdown zone to the Level B harassment area is 0.19. This
activity is predicted to take place on 48 construction days (48
construction days / 7 days = 6.9 7-day construction periods). As such,
34 takes by Level A harassment are proposed for authorization [(0.09 x
1 group x 24 harbor seal x 1 7-day construction periods) + (0.19 x 1
group x 24 harbor seal x 6.9 7-day construction periods) = 34 takes by
Level A harassment].
During all impact pile driving, the Level A harassment zone is
larger than the Level B harassment zone. These activities are predicted
to take place on 44 construction days (44 construction days / 7 days =
6.3 1-week construction periods). Estimated take by Level A harassment
for these activities result in 151 based on 1 group x 24 harbor seal x
6.3 14 day construction periods (1 x 24 x 6.3 = 151.2 takes by Level A
harassment).
Takes by Level B harassment were modified to deduct the proposed
amount of take by Level A harassment estimated in cases where the Level
A harassment zone is smaller than the Level B harassment zone (i.e.,
882 total exposures-34 takes by Level A harassment estimated during DTH
activities = 848 takes by Level B harassment). Therefore, for harbor
seal, NMFS proposes to authorize 185 takes by Level A harassment (34
takes + 151 takes) and 848 takes by Level B harassment, for a total of
1,033 takes in year 1.
In year 2, the duration of the construction for which the Level B
harassment zone is larger than the Level A harassment zone is 76 days
(10.9 is the basic 7 day period that corresponds to 1 construction
week). This results in 262 takes by Level B harassment of harbor seal
(24 harbor seal x 10.9 7-day periods).
During all DTH activities, the Level A harassment zone is larger
than the shutdown zone, but smaller than the Level B harassment zone.
As such it is possible that harbor seal may enter the Level A
harassment zone and stay long enough to incur AUD INJ before exiting.
For DTH of 19-24-in steel piles, the ratio of the Level A harassment
area that exceeds the shutdown zone to the Level B harassment area is
0.09. This activity is predicted to take place on 6 construction days
(6 construction days / 7 days = 0.86 7-day construction periods). For
DTH of 24-42-in steel piles, the ratio of the Level A harassment area
that exceeds the shutdown zone to the Level B harassment area is 0.19.
This activity is predicted to take place on 18 construction days (18
construction days / 7 days = 2.6 7-day construction periods). As such,
14 takes by Level A harassment are proposed for authorization [(0.09 x
1 group x 24 harbor seal x 0.86 7-day construction periods) + (0.19 x 1
group x 14 harbor seal x 2.6 7-day construction periods) = 13.57 takes
by Level A harassment].
During all impact pile driving, the Level A harassment zone is
larger than the Level B harassment zone. These activities are predicted
to take place on 17 construction days (17 construction days / 7 days =
2.4 7-day construction periods). Estimated take by Level A harassment
for these activities result in 58 based on 1 group x 24 harbor seal x
2.4 7-day construction periods (1 x 24 x 2.4 = 57.6 takes by Level A
harassment).
Takes by Level B harassment were modified to deduct the proposed
amount of take by Level A harassment estimated in cases where the Level
A zone is smaller than the Level B zone (i.e., 262 total exposures-14
takes by Level A harassment estimated during DTH activities = 248 takes
by Level B harassment). Therefore, for harbor seal, NMFS proposes to
authorize 72 takes by Level A harassment (14 takes + 58 takes) and 248
takes by Level B harassment, for a total of 320 takes in year 2.
Northern Elephant Seal
Although rare, Northern elephant seals could occur in the project
area (Van Daele, 2024, personal communication). NMFS predicts that one
northern elephant seal could occur within the Level B harassment zone
every 2 construction weeks (14 days), each year. In year 1, the
duration of the construction for which the Level B harassment zone is
larger than the Level A harassment zone is 257 days (18.4 is the basic
14 day period that corresponds to 2 construction weeks). This results
in 19 takes by Level B harassment of northern fur seal (1 northern
elephant
[[Page 12226]]
seal x 18.4 14-day periods). Because exposure estimates are low, and
the Level A harassment zones are larger than are likely observable
during impact pile driving and DTH, NMFS proposed to authorize these 19
takes by either Level A harassment or Level B harassment.
In year 2, the duration of the construction for which the Level B
harassment zone is larger than the Level A harassment zone is 76 days
(5.4 is the basic 14 day period that corresponds to 2 construction
weeks). This results in six takes by Level B harassment of northern
elephant seal (1 northern elephant seal x 5.4 14-day periods). Because
exposure estimates are low, and the Level A harassment zones are larger
than are likely observable during impact pile driving and DTH, NMFS
proposed to authorize these six takes by either Level A harassment or
Level B harassment.
Table 10--Take by Stock and Harassment Type and as a Percentage of Stock Abundance
--------------------------------------------------------------------------------------------------------------------------------------------------------
Proposed take--year 1 Proposed take--year 2 Take as
---------------------------------------------------- percentage of
stock
Species Stock Level A Level B Level A Level B abundance--
harassment harassment harassment harassment year 1, (year
2)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Gray Whale...................................... Eastern N Pacific................. 0 3 0 3 (<1)
Fin Whale....................................... Northeast Pacific................. 0 6 0 6 *, (*)
Humpback Whale.................................. Hawai[revaps]i.................... 0 2 0 2 <1, (<1)
Mexico-N Pacific.................. *, (*)
Western N Pacific................. <1, (<1)
Minke Whale..................................... Alaska............................ 0 2 0 2 *, (*)
Killer Whale.................................... Eastern North Pacific-Alaska 0 62 0 18 <1, (<1)
Resident.
Eastern North Pacific-Gulf of 11, (3)
Alaska, Aleutian Islands, and
Bering Sea.
Pacific White-sided Dolphin..................... North Pacific..................... 0 10 0 10 <1, (<1)
Dall's Porpoise................................. Alaska............................ 10 31 5 8 *, (*)
Harbor Porpoise................................. Gulf of Alaska.................... 14 47 6 20 <1, (<1)
----------------------------------------------------
Northern Fur Seal............................... Eastern Pacific................... 9
3 <1, (<1)
----------------------------------------------------
Steller Sea Lion................................ Western........................... 2 36 1 10 <1, (<1)
Harbor Seal..................................... South Kodiak...................... 185 848 72 248 3.9, (1.2)
----------------------------------------------------
Northern Elephant Seal.......................... CA Breeding....................... 19
6 <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. 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.
Shutdown Zones--For all pile driving and DTH activities, USCG
proposes to implement shutdowns within designated zones. The purpose of
a shutdown zone is generally to define an area within which shutdown of
the activity would occur upon sighting of a marine mammal (or in
anticipation of an animal entering the defined area). Shutdown zones
vary based on the activity type and marine mammal hearing group (table
11 and 12). In most cases, the shutdown zones are based on the
estimated Level A harassment isopleth distances for each hearing group.
However, in cases where it would be challenging to detect marine
mammals at the Level A harassment isopleth (e.g., for very high-
frequency cetaceans, phocids, and otariids during most impact pile
driving), smaller shutdown zones have been proposed (table 11 and 12).
Construction supervisors and crews, PSOs, and relevant USCG staff
must avoid direct physical interaction with marine mammals during
construction activity. If a marine mammal comes within 25 m of such
activity, operations must cease and vessels must reduce speed to the
minimum level required to maintain steerage and safe working
conditions, as necessary to avoid direct physical interaction. 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
[[Page 12227]]
shutdown zone indicated in table 11 and 12, or 30 minutes (ESA-listed
large whales) or 15 minutes (all other species) 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 harassment zone. If a marine
mammal species not covered under this IHA enters a harassment 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 harassment zone or if
15 minutes have passed since the last observation.
Table 11--Proposed Shutdown Zones (m): Year 1
--------------------------------------------------------------------------------------------------------------------------------------------------------
Pile driving method Pile type Pile size LF HF VHF PW OW
--------------------------------------------------------------------------------------------------------------------------------------------------------
Vibratory Installation and Extraction......... Timber.......................... 14 25 25 25 25 25
24
Steel........................... 12
14
24
36 60 50 80 30
42 50 70 25
Steel/Concrete.................. 24 30 25 40
Precast Concrete................ 24 25 30
Vibroflot....................... 30 30 40
Impact Pile Driving........................... Steel........................... 24 1,940 250 300 300 300
42 3,200 410
Precast Concrete................ 24 560 80 190
DTH........................................... Steel........................... 19-24 800 110 300
24-42 1,720 220
--------------------------------------------------------------------------------------------------------------------------------------------------------
Table 12--Proposed Shutdown Zones (m): Year 2
--------------------------------------------------------------------------------------------------------------------------------------------------------
Pile driving method Pile type Pile size LF HF VHF PW OW
--------------------------------------------------------------------------------------------------------------------------------------------------------
Vibratory Installation and Extraction......... Steel........................... 24 25 25 25 25 25
30 25
36 60 50 80 30
42 50 70 25
Impact Pile Driving........................... Steel........................... 24 1,940 250 300 300 300
30
36 3,720 480
42 3,200 410
DTH........................................... Steel........................... 19-24 800 110
24-42 1,720 220
--------------------------------------------------------------------------------------------------------------------------------------------------------
Protected Species Observers (PSOs)--The number and placement of
PSOs during all construction activities (described in the Proposed
Monitoring and Reporting section) would ensure that the entire shutdown
zone is visible. USCG would employ at least one PSOs during all
vibratory pile driving and removal activities and at least two PSOs
during all impact pile driving and DTH activities.
Monitoring for Level A and Level B Harassment--PSOs would monitor
the shutdown zones and beyond to the extent that PSOs can see.
Monitoring beyond the shutdown zones enables observers to be aware of
and communicate the presence of marine mammals in the project areas
outside the shutdown zones and thus prepare for a potential cessation
of activity should the animal enter the shutdown zone. If a marine
mammal enters either harassment zone, PSOs will document the marine
mammal's presence and behavior.
Pre- and Post-Activity Monitoring--Prior to the start of daily in-
water construction activity, or whenever a break in pile driving of 30
minutes or longer occurs, PSOs would observe the shutdown zones and as
much as the harassment zones as possible for a period of 30 minutes.
Pre-start clearance monitoring must be conducted during periods of
visibility sufficient for the lead PSO to determine that the shutdown
zones are clear of marine mammals. If the shutdown zone is obscured by
fog or poor lighting conditions, in-water construction activity will
not be initiated until the entire shutdown zone is visible. Pile
driving may commence following 30 minutes of observation when the
determination is made that the shutdown zones are clear of marine
mammals. If a marine mammal is observed entering or within shutdown
zones, pile driving activity must be delayed or halted. If pile driving
is delayed or halted due to the presence of a marine mammal, the
activity may not commence or resume until either the animal has
voluntarily exited and been visually confirmed beyond the shutdown zone
or 30 minutes (ESA-listed large whales) or 15 minutes have passed
without re-detection of the animal. If a marine mammal for which take
by Level B harassment is authorized is present in the Level B
harassment zone, activities may begin.
Soft-Start--The use of soft-start procedures are believed to
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. For impact pile driving, contractors
would be required to provide an initial set of three strikes from the
hammer at reduced energy, with each strike followed by a
[[Page 12228]]
30-second waiting period. This procedure would be conducted a total of
three times before impact pile driving begins. Soft start would be
implemented at the start of each day's impact pile driving and at any
time following cessation of impact pile driving for a period of 30
minutes or longer. Soft start is not required during vibratory pile
driving activities.
Based on our evaluation of the applicant's proposed measures, NMFS
has preliminarily determined that the proposed mitigation measures
provide the means of effecting the least practicable impact on the
affected species or stocks and their habitat, paying particular
attention to rookeries, mating grounds, and areas of similar
significance, 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.
Visual Monitoring
Marine mammal monitoring during pile driving activities must be
conducted by NMFS-approved PSOs in a manner consistent with the
following:
<bullet> PSOs must be independent of the activity contractor (for
example, employed by a subcontractor), and have no other assigned tasks
during monitoring periods;
<bullet> At least one PSO must have prior experience performing the
duties of a PSO during construction activity pursuant to a NMFS-issued
incidental take authorization;
<bullet> Other PSOs may substitute other relevant experience,
education (degree in biological science or related field) or training
for experience performing the duties of a PSO during construction
activities pursuant to NMFS-issued take authorization;
<bullet> Where a team of three or more PSOs is required, a lead
observer or monitoring coordinator will be designated. The lead
observer will be required to have prior experience working as a marine
mammal observer during construction activity pursuant to a NMFS-issued
incidental take authorization; and,
<bullet> PSOs must be approved by NMFS prior to beginning any
activity subject to this IHA.
PSOs should also have the following qualifications:
<bullet> Ability to conduct field observations and collect data
according to assigned protocols;
<bullet> Experience or training in the field identification of
marine mammals, including identification of behaviors;
<bullet> Sufficient training, orientation, or experience with the
construction operation to provide for personal safety during
observations;
<bullet> Writing skills sufficient to prepare a report of
observations including, but not limited to, the number and species of
marine mammals observed; dates and times when in-water construction
activities were conducted; dates, times, and reason for implementation
of mitigation (or why mitigation was not implemented when required);
and marine mammal behavior; and,
<bullet> Ability to communicate orally, by radio or in person, with
project personnel to provide real-time information on marine mammals
observed in the area as necessary.
Visual monitoring would be conducted by trained PSOs positioned at
suitable vantage points, such as the project site, and the southern tip
of Nyman Peninsula. During vibratory pile driving and removal, at least
one PSO would placed near the pile driving site and have an
unobstructed view of all water within the shutdown zone. During impact
pile driving and DTH, a second PSO would be placed at a location like
the southern end of Nyman Peninsula ensure the larger shutdown zones
would be observable as well.
Monitoring would be conducted 30 minutes before, during, and 30
minutes after all in water construction activities. In addition, PSOs
will record all incidents of marine mammal occurrence, regardless of
distance from activity, and will 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.
Reporting
USCG would submit a draft marine mammal monitoring report to NMFS
within 90 days after the completion of pile driving activities, or 60
days prior to a requested date of issuance of any future IHAs for the
project, or other projects at the same location, whichever comes first.
The marine mammal monitoring report will include an overall description
of work completed, a narrative regarding marine mammal sightings, and
associated PSO data sheets. Specifically, the report will include:
<bullet> Dates and times (begin and end) of all marine mammal
monitoring;
<bullet> Construction activities occurring during each daily
observation period, including: (1) the number and type of piles that
were driven and the method (e.g., impact or vibratory); and (2) total
duration of driving time for each pile (vibratory driving) and number
of strikes for each pile (impact driving);
<bullet> PSO locations during marine mammal monitoring;
<bullet> Environmental conditions during monitoring periods (at
beginning and end of PSO shift and whenever conditions change
significantly), including Beaufort sea state and other relevant weather
conditions including
[[Page 12229]]
cloud cover, fog, sun glare, and overall visibility to the horizon, and
estimated observable distance;
<bullet> Upon observation of a marine mammal, the following
information: (1) name of PSO who sighted the animal(s) and PSO location
and activity at time of sighting; (2) time of sighting; (3)
identification of the animal(s) (e.g., genus/species, lowest possible
taxonomic level, or unidentified), PSO confidence in identification,
and the composition of the group if there is a mix of species; (4)
distance and location of each observed marine mammal relative to the
pile being driven for each sighting; (5) estimated number of animals
(min/max/best estimate); (6) estimated number of animals by cohort
(adults, juveniles, neonates, group composition, etc.); (7) animal's
closest point of approach and estimated time spent within the
harassment zone; (8) description of any marine mammal behavioral
observations (e.g., observed behaviors such as feeding or traveling),
including an assessment of behavioral responses thought to have
resulted from the activity (e.g., no response or changes in behavioral
state such as ceasing feeding, changing direction, flushing, or
breaching);
<bullet> Number of marine mammals detected within the harassment
zones, by species; and,
<bullet> Detailed information about implementation of any
mitigation (e.g., shutdowns and delays), a description of specific
actions that ensued, and resulting changes in behavior of the
animal(s), if any.
A final report must be prepared and submitted within 30 calendar
days following receipt of any NMFS comments on the draft report. If no
comments are received from NMFS within 30 calendar days of receipt of
the draft report, the report shall be considered final. All PSO data
would be submitted electronically in a format that can be queried such
as a spreadsheet or database and would be submitted with the draft
marine mammal report.
In the event that personnel involved in the construction activities
discover an injured or dead marine mammal, the Holder must report the
incident to the OPR, NMFS (<a href="/cdn-cgi/l/email-protection#89d9dba7c0ddd9a7c4e6e7e0fde6fbe0e7eedbecf9e6fbfdfac9e7e6e8e8a7eee6ff"><span class="__cf_email__" data-cfemail="4b1b1965021f1b65062425223f243922252c192e3b24393f380b25242a2a652c243d">[email protected]</span></a> and
<a href="/cdn-cgi/l/email-protection" class="__cf_email__" data-cfemail="8fe6fbffa1e9e3eae2e6e1e8cfe1e0eeeea1e8e0f9">[email protected]</a>) and Alaska Regional Stranding network (877-925-
7773) as soon as feasible. If the death or injury was clearly caused by
the specified activity, the Holder must immediately cease the
activities until NMFS OPR 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 this IHA. The Holder
must not resume their activities until notified by NMFS. The report
must include the following information:
<bullet> Time, date, and location (latitude/longitude) of the first
discovery (and updated location information if known and applicable);
<bullet> Species identification (if known) or description of the
animal(s) involved;
<bullet> Condition of the animal(s) (including carcass condition if
the animal is dead);
<bullet> Observed behaviors of the animals(s), if alive;
<bullet> If available, photographs or video footage of the
animal(s); and,
<bullet> General circumstances under which the animal was
discovered.
Negligible Impact Analysis and Determination
NMFS has defined negligible impact as an impact resulting from the
specified activity that cannot be reasonably expected to, and is not
reasonably likely to, adversely affect the species or stock through
effects on annual rates of recruitment or survival (50 CFR 216.103). A
negligible impact finding is based on the lack of likely adverse
effects on annual rates of recruitment or survival (i.e., population-
level effects). An estimate of the number of takes alone is not enough
information on which to base an impact determination. In addition to
considering estimates of the number of marine mammals that might be
``taken'' through harassment, NMFS considers other factors, such as the
likely nature of any impacts or responses (e.g., intensity, duration),
the context of any impacts or responses (e.g., critical reproductive
time or location, foraging impacts affecting energetics), as well as
effects on habitat, and the likely effectiveness of the mitigation. We
also assess the number, intensity, and context of estimated takes by
evaluating this information relative to population status. Consistent
with the 1989 preamble for NMFS' implementing regulations (54 FR 40338,
September 29, 1989), the impacts from other past and ongoing
anthropogenic activities are incorporated into this analysis via their
impacts on the baseline (e.g., as reflected in the regulatory status of
the species, population size and growth rate where known, ongoing
sources of human-caused mortality, or ambient noise levels).
To avoid repetition, the 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.
Pile driving, removal, and DTH activities associated with the
project, 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 pile
driving and removal. Potential takes could occur if individuals are
present in the ensonified zone when these activities are underway.
No serious injury or mortality is expected in either year, even in
the absence of required mitigation measures, given the nature of the
activities. Further, no take by Level A harassment is anticipated for
any low-frequency or high-frequency cetaceans, due to the rarity of the
species near the project area and the application of proposed
mitigation measures, such as shutdown zones that encompass the Level A
harassment zones for these species (see Proposed Mitigation section).
In both Year 1 and Year 2, take by Level A harassment is proposed
for authorization for six species (Dall's porpoise, harbor porpoise,
northern fur seal, Steller sea lion, harbor seal, and northern elephant
seal). 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 such as the low-frequency
region below 2 kHz), not severe hearing impairment or impairment within
the ranges of greatest hearing sensitivity. Animals would need to be
exposed to higher levels and/or longer duration than are expected to
occur here in order to incur any more than a small degree of PTS.
Further, in both year 1 and year 2, the amount of take by Level A
harassment proposed for authorization is very low. For six species,
NMFS anticipates no take by Level A harassment over the duration of
USCG's planned activities (both years); In year 1, NMFS expects no more
than 6 takes by Level A harassment for Dall's porpoise in year 1 and 5
in year 2; 15 takes by Level A harassment for harbor porpoise in year 1
and 5 in year 2; 19 takes by Level A
[[Page 12230]]
harassment for northern elephant seal in year 1 and 6 in year 2; and 2
takes by Level A harassment for Steller sea lion in year 1 and 1 in
year 2. The proposed amount of take by Level A harassment for harbor
seal is a bit larger--185 takes in year 1 and 73 in year 2. However,
for all hearing groups, 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
potentially incurred would not be expected to affect the reproductive
success or survival of any individuals, much less result in adverse
impacts on the species or stock.
Additionally, some subset of the individuals that are behaviorally
harassed could also simultaneously incur some small degree of TTS for a
short duration of time. However, since the hearing sensitivity of
individuals that incur TTS is expected to recover completely within
minutes to hours, it is unlikely that the brief hearing impairment
would affect the individual's long-term ability to forage and
communicate with conspecifics, and would therefore not likely impact
reproduction or survival of any individual marine mammal, let alone
adversely affect rates of recruitment or survival of the species or
stock.
Effects on individuals that are taken by Level B harassment in the
form of behavioral disruption, on the basis of reports in the
literature as well as monitoring from other similar activities, would
likely be limited to reactions such as avoidance, increased swimming
speeds, increased surfacing time, or decreased foraging (if such
activity were occurring) (e.g., Thorson and Reyff, 2006). Most likely,
individuals would simply move away from the sound source and
temporarily avoid the area where pile driving is occurring. If sound
produced by project activities is sufficiently disturbing, animals are
likely to simply avoid the area while the activities are occurring. We
expect that any avoidance of the project areas by marine mammals would
be temporary in nature and that any marine mammals that avoid the
project areas during construction would not be permanently displaced.
Short-term avoidance of the project areas and energetic impacts of
interrupted foraging or other important behaviors is unlikely to affect
the reproduction or survival of individual marine mammals, and the
effects of behavioral disturbance on individuals is not likely to
accrue in a manner that would affect the rates of recruitment or
survival of any affected stock.
The project is also not expected to have significant adverse
effects on affected marine mammals' habitats. The project activities
would not modify existing marine mammal habitat for a significant
amount of time. The activities may cause a low level of turbidity in
the water column and some fish may leave the area of disturbance, thus
temporarily impacting marine mammals' foraging opportunities in a
limited portion of the foraging range; but, because of the short
duration of the activities and the relatively small area of the habitat
that may be affected (with no known particular importance to marine
mammals), the impacts to marine mammal habitat are not expected to
cause significant or long-term negative consequences.
Steller sea lions are not common in the project area, and there are
no essential primary constituent elements (biological or physical
features within designated critical habitat that are essential to the
conservation of the listed species), such as haulouts or rookeries,
present. The nearest haulout is 4 km away on a man-made float.
Therefore, the project is not expected to have significant adverse
effects on the critical habitat of Western DPS Steller sea lions.
While waters off Kodiak have been identified as BIAs for gray
whale, fin whale, and humpback whale, only a small portion of the
project area at the mouth of Womens Bay overlaps with a minimal part of
these identified areas. The shallow waters of Womens Bay do not
represent habitat for these species and occurrence of these species is
low in the project area.
In addition, it is unlikely that minor noise effects in a small,
localized area of habitat would have any effect on the reproduction or
survival of any individuals, much less these stocks' annual rates of
recruitment or survival. In combination, we believe that these factors,
as well as the available body of evidence from other similar
activities, demonstrate that the potential effects of the specified
activities would have only minor, short-term effects on individuals.
The specified activities are not expected to impact rates of
recruitment or survival and would therefore not result in population-
level impacts.
In summary and as described above, the following factors primarily
support our preliminary determination that the impacts resulting from
this activity are not expected to adversely affect any of the species
or stocks through effects on annual rates of recruitment or survival:
<bullet> No serious injury or mortality is anticipated or proposed
for authorization;
<bullet> No take by Level A harassment is proposed for 6 out of 12
species;
<bullet> Take by Level A harassment would be very small amounts for
most species and of a low severity;
<bullet> For all species, Womens Bay is a very small and peripheral
part of their range;
<bullet> Proposed takes by Level B harassment are relatively low
for most stocks. Level B harassment would be primarily in the form of
behavioral disturbance, resulting in avoidance of the project areas
around where impact or vibratory pile driving is occurring, with some
low-level TTS that may limit the detection of acoustic cues for
relatively brief amounts of time in relatively confined footprints on
their populations;
<bullet> The ensonified areas are very small relative to the
overall habitat ranges of all species and stocks, and overlap with
known areas of important habitat is minimal; and,
<bullet> The lack of anticipated significant or long-term negative
effects to marine mammal habitat.
Based on the analysis contained herein of the likely effects of the
specified activity on ma
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