Notice2023-09041
Takes of Marine Mammals Incidental to Specified Activities; Taking Marine Mammals Incidental to the Port of Nome Modification Project in Nome, Alaska
Primary source
Metadata and text below are from the Federal Register, a public-domain U.S. government work. Always verify the official published version before relying on it for any legal matter.
Published
May 2, 2023
Issuing agencies
Commerce DepartmentNational Oceanic and Atmospheric Administration
Abstract
NMFS has received a request from the U.S. Army Corps of Engineers (USACE) for authorization to take marine mammals incidental to the Port of Nome Modification Project in Nome, Alaska. Pursuant to the Marine Mammal Protection Act (MMPA), NMFS is requesting comments on its proposal to issue an incidental harassment authorization (IHA) to incidentally take marine mammals during the specified activities. NMFS is also requesting comments on a possible one-time, 1-year renewal that could be issued under certain circumstances and if all requirements are met, as described in Request for Public Comments at the end of this notice. NMFS will consider public comments prior to making any final decision on the issuance of the requested MMPA authorization and agency responses will be summarized in the final notice of our decision.
Full Text
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<title>Federal Register, Volume 88 Issue 84 (Tuesday, May 2, 2023)</title>
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[Federal Register Volume 88, Number 84 (Tuesday, May 2, 2023)]
[Notices]
[Pages 27464-27487]
From the Federal Register Online via the Government Publishing Office [<a href="http://www.gpo.gov">www.gpo.gov</a>]
[FR Doc No: 2023-09041]
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DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
[RTID 0648-XC662]
Takes of Marine Mammals Incidental to Specified Activities;
Taking Marine Mammals Incidental to the Port of Nome Modification
Project in Nome, Alaska
AGENCY: National Marine Fisheries Service (NMFS), National Oceanic and
Atmospheric Administration (NOAA), Commerce.
ACTION: Notice; proposed incidental harassment authorization; request
for comments on proposed authorization and possible renewal.
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SUMMARY: NMFS has received a request from the U.S. Army Corps of
Engineers (USACE) for authorization to take marine mammals incidental
to the Port of Nome Modification Project in Nome, Alaska. Pursuant to
the Marine Mammal Protection Act (MMPA), NMFS is requesting comments on
its proposal to issue an incidental harassment authorization (IHA) to
incidentally take marine mammals during the specified activities. NMFS
is also requesting comments on a possible one-time, 1-year renewal that
could be issued under certain circumstances and if all requirements are
met, as described in Request for Public Comments at the end of this
notice. NMFS will consider public comments prior to making any final
decision on the issuance of the requested MMPA authorization and agency
responses will be summarized in the final notice of our decision.
DATES: Comments and information must be received no later than June 1,
2023.
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#652c31354b2104130c16250b0a04044b020a13"><span class="__cf_email__" data-cfemail="7e372a2e503a1f08170d3e10111f1f50191108">[email protected]</span></a>.
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="http://www.fisheries.noaa.gov/permit/incidental-take-authorizations-under-marine-mammal-protection-act">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: Leah Davis, Office of Protected
Resources, NMFS, (301) 427-8401. 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 above.
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 mitigation,
monitoring and reporting of the takings are set forth. The definitions
of all applicable MMPA statutory terms cited above are included in the
relevant sections below.
National Environmental Policy Act
To comply with the National Environmental Policy Act of 1969 (NEPA;
42 U.S.C. 4321 et seq.) and NOAA Administrative Order (NAO) 216-6A,
NMFS must review our proposed action (i.e., the issuance of an
[[Page 27465]]
IHA) with respect to potential impacts on the human environment. This
action is consistent with categories of activities identified in
Categorical Exclusion B4 (IHAs with no anticipated serious injury or
mortality) of the Companion Manual for NOAA Administrative Order 216-
6A, which do not individually or cumulatively have the potential for
significant impacts on the quality of the human environment and for
which we have not identified any extraordinary circumstances that would
preclude this categorical exclusion. Accordingly, NMFS has
preliminarily determined that the issuance of the proposed IHA
qualifies to be categorically excluded from further NEPA review.
We will review all comments submitted in response to this notice
prior to concluding our NEPA process or making a final decision on the
IHA request.
Summary of Request
On October 31, 2022, NMFS received a request from USACE for an IHA
to take marine mammals incidental to construction activities in Nome,
Alaska. Following NMFS' review of the application, USACE submitted a
revised version on February 21, 2023 and a final version on February
23, 2023 that clarified a few minor errors. The application was deemed
adequate and complete on March 30, 2023. USACE's request is for take of
10 species of marine mammals by Level B harassment only. Neither USACE
nor NMFS expect serious injury or mortality to result from this
activity and, therefore, an IHA is appropriate.
This proposed IHA would cover 1 year of a larger project for which
USACE intends to request take authorization for subsequent facets of
the project. The larger 7-year project involves expansion of the Port
of Nome.
Description of Proposed Activity
Overview
USACE is planning to modify the Port of Nome in Nome, Alaska to
increase capacity and alleviate congestion at existing port facilities.
Vibratory and impact pile driving would introduce underwater sounds
that may result in take, by Level B harassment, of marine mammals. This
proposed IHA would authorize take for Year 1 of Phase 1 of the project,
which is scheduled to begin in May 2024. Work would occur during
daylight hours and approximately 12 hours per day during the open water
season.
Dates and Duration
The proposed IHA would be effective from May 1, 2024 to April 30,
2025. Work would occur during the open water season, roughly May
through October. In-water construction activities would only occur
during daylight hours, and typically over a 12-hour workday. However,
when needed and due to the long summer day length at Nome's latitude,
24-hour, multi-shift operations may occur. For calculations herein,
USACE conservatively assumed that 24 hours of work could occur in a
given day (e.g., in estimating the number of piles for installation on
a given day). Pile driving is expected to occur over 85 in-water work
days.
Specific Geographic Region
The Port of Nome Modification Project is located in Norton Sound,
just offshore of Nome, Alaska. All construction activities would occur
within approximately 3,600 feet (ft; 1,097 m) of the shoreline. The
seabed in this area is flat and featureless, with bottom sediments
consisting of sand and silt, with scattered cobbles and boulders. The
nearshore waters are shallow and deepen very gradually, reaching a
depth of 60 ft (18 m) at roughly 2 nautical miles (nmi; 3.7 km)
offshore. In the Nome area, sea ice formation typically occurs in early
November each year with spring break-up usually occurring in late May.
[GRAPHIC] [TIFF OMITTED] TN02MY23.002
Figure 1--Project Location
[[Page 27466]]
Detailed Description of the Specified Activity
The City of Nome and USACE are proposing to expand the Port of Nome
to provide much-needed additional capacity to serve the Arctic as well
as to alleviate congestion at the existing port facilities. As noted
above, this proposed IHA would authorize take associated with Year 1 of
Phase 1 of the project only. Please refer to USACE's application for
additional information about project components planned for the period
beyond Year 1.
The USACE estimates that Year 1 activities would include
mobilization, removal of the breakwater spur, development of the quarry
for rock and gravel (i.e., fill), dredging of the causeway footprint to
accommodate for armor stone installation, pile driving for the OPEN
CELL SHEET PILE\TM\ (OCSP) dock, and placement of gravel fill inside
new sheet pile cells. Additionally, USACE anticipates approximately 20
round trip vessel trips (i.e., barge, support tugs, fuel, etc.) to
occur between Nome and Anchorage during Year 1. With the exception of
pile driving, these activities are not anticipated to result in take.
Mobilization activities would occur on land, as would development of
the quarry for rock and gravel (likely to occur at Cape Nome quarry).
While marine mammals may behaviorally respond in some small degree to
the noise generated by dredging operations, given the slow, predictable
movements of these vessels, and absent any other contextual features
that would cause enhanced concern, NMFS does not expect USACE's planned
dredging to result in the take of marine mammals. (Though, as noted
below, USACE has conservatively proposed to implement a 300 m shutdown
zone for dredging.)
Gravel fill deposition would produce a continuous sound of a
relatively short duration, does not require seafloor penetration, and
would not affect habitat for marine mammals and their prey beyond that
already affected by installation of the OCSP, discussed below. Further,
placement of gravel fill would occur in a dry area behind the sheet
piles, and placement would occur in a controlled manner so as not to
compromise the newly installed piles. Gravel deposition is not expected
to result in marine mammal harassment and it is not discussed further.
Because vessels will be in transit, exposure to ship noise will be
temporary, relatively brief and will occur in a predictable manner, and
also the sounds are of relatively lower levels. Elevated background
noise from multiple vessels and other sources can interfere with the
detection or interpretation of acoustic cues, but the brief exposures
to one or two USACE vessels at a time would be unlikely to disrupt
behavioral patterns in a manner that would qualify as take.
The OCSP dock would consist of approximately 66 cells when
complete. Cells are constructed utilizing flat-web sheet piles,
connector x-wyes (fabricated from three one-half-width sheet pile
sections), and anchor piles. After all the piles for a cell have been
installed, clean gravel fill would be placed within the cell. This
process would continue sequentially until all the sheet pile cells are
installed and backfilled. The cells are typically constructed one at a
time. The contractor may use two sets of templates to allow for
completing the pile driving of one cell and starting on the next while
removing and reinstalling the template from the completed cell.
However, only one hammer would be used at a time.
Table 1 lists the number of each pile size and type that USACE
anticipates installing and/or removing during Year 1. USACE anticipates
driving piles with a vibratory hammer; however, it may use an impact
hammer if hard driving conditions are encountered and use of the
vibratory hammer is unsuccessful.
Table 1--Number and Type of Piles Planned for Installation or Removal
------------------------------------------------------------------------
Number of
Pile type Installation/removal piles
------------------------------------------------------------------------
Temporary template piles.......... Installation and \a\ 228
(Pipe piles <=24'')............... Removal.
(Alternate) Temporary template Installation and 228
piles (H-piles 14'') a b. Removal.
Anchor piles6 (14'' HP14x89 or Installation........ 27
similar).
Sheet piles....................... Installation........ 1,600
(20'' PS31 or similar)............
Fender piles...................... Installation........ 21
(Pipe piles 36'').................
------------------------------------------------------------------------
\a\ Each of the 228 piles would be both installed and removed.
\b\ H-piles may be used as an alternate in place of the pipe piles.
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="http://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessments">www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessments</a>) and more
general information about these species (e.g., physical and behavioral
descriptions) may be found on NMFS' website (<a href="https://www.fisheries.noaa.gov/find-species">https://www.fisheries.noaa.gov/find-species</a>).
Table 2 lists all species or stocks for which take is expected and
proposed to be authorized for this activity, and summarizes information
related to the population or stock, including regulatory status under
the MMPA and Endangered Species Act (ESA) and potential biological
removal (PBR), where known. PBR is defined by the MMPA as the maximum
number of animals, not including natural mortalities, that may be
removed from a marine mammal stock while allowing that stock to reach
or maintain its optimum sustainable population (as described in NMFS'
SARs). While no serious injury or mortality is anticipated or proposed
to be authorized here, PBR and annual serious injury and mortality from
anthropogenic sources are included here as gross indicators of the
status of the species or stocks and other threats.
[[Page 27467]]
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 SARs (e.g., Muto et al., 2022). All values presented
in Table 2 are the most recent available at the time of publication
(including from the draft 2022 SARs) and are available online at:
<a href="http://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessments">www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessments</a>).
Table 2--Marine Mammal Species \1\ Likely To Occur Near the Project Area That May Be Taken by USACE's 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.. Eastern N Pacific...... -, -, N 26,960 (0.05, 25,849, 801 131
2016).
Family Balaenopteridae (rorquals):
Minke Whale..................... Balaenoptera AK..................... -, -, N N/A (N/A, N/A, N/A) UND 0
acutorostrata. \5\.
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Odontoceti (toothed whales, dolphins, and porpoises)
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Family Delphinidae:
Killer Whale.................... Orcinus orca........... Eastern North Pacific -, -, N 1,920 \6\ (N/A, 1,920, 19 1.3
Alaska Resident. 2019).
Killer Whale.................... Orcinus orca........... Eastern North Pacific -, -, N 587 \6\ (N/A, 587, 5.9 0.8
Gulf of Alaska, 2012).
Aleutian Islands and
Bering Sea Transient.
Family Monodontidae (white whales):
Beluga Whale.................... Delphinapterus leucas.. Eastern Bering Sea..... -,-, N 12,269 (0.118, 11,112, 267 226
2017).
Family Phocoenidae (porpoises):
Harbor Porpoise................. Phocoena phocoena...... Bering Sea............. -, -, Y UNK (UNK, N/A, 2008) UND \7\ 0.4
\7\.
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Order Carnivora--Pinnipedia
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Family Otariidae (eared seals and
sea lions):
Steller Sea Lion................ Eumetopias jubatus..... Western................ E, D, Y 52,932 \8\ (N/A, 318 254
52,932, 2019).
Family Phocidae (earless seals):
Bearded Seal.................... Erignathus barbatus.... Beringia............... T, D, Y UND (UND, UND, 2013) \9\ UND 6,709
\9\.
Ribbon Seal..................... Histriophoca fasciata.. Unidentified........... -, -, N 184,697 (N/A, 163,086, 9,785 163
2013).
Ringed Seal..................... Pusa hispida........... Arctic................. T, D, Y UND (UND, UND, 2013) \10\ UND 6,459
\10\.
Spotted Seal.................... Phoca largha........... Bering................. -, -, N 461,625 (N/A, 423,237, 25,394 5,254
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-caused mortality
exceeds PBR or which is determined to be declining and likely to be listed under the ESA within the foreseeable future. Any species or stock listed
under the ESA is automatically designated under the MMPA as depleted and as a strategic stock.
\3\ NMFS marine mammal stock assessment reports online at: <a href="https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessment-reports-region">https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessment-reports-region</a>. CV is coefficient of variation; Nmin is the minimum estimate of stock abundance.
\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\ Reliable population estimates are not available for this stock. Please see Friday et al. (2013) and Zerbini et al. (2006) for additional information
on numbers of minke whales in Alaska.
\6\ Nest is based upon counts of individuals identified from photo-ID catalogs.
\7\ The best available abundance estimate and Nmin are 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. PBR for this stock is undetermined due to this estimate being older than 8 years.
\8\ Nest is best estimate of counts, which have not been corrected for animals at sea during abundance surveys.
\9\ Reliable population estimate for the entire stock not available. PBR is based upon the negatively biased Nmin for bearded seals in the U.S. portion
of the stock.
\10\ A reliable population estimate for the entire stock is not available. Using a sub-sample of data collected from the U.S portion of the Bering Sea,
an abundance estimate of 171,418 ringed seals has been calculated, but this estimate does not account for availability bias due to seals in the water
or in the shore fast ice zone at the time of the survey. The actual number of ringed seals in the U.S. portion of the Bering Sea is likely much
higher. Using the Nmin based upon this negatively biased population estimate, the PBR is calculated to be 4,755 seals, although this is also a
negatively biased estimate.
As indicated above, all 11 species (with 12 managed stocks) in
Table 2 temporally and spatially co-occur with the activity to the
degree that take is reasonably likely to occur. All species that could
potentially occur in the proposed survey areas are included in Table 3-
1 of USACE's IHA application. While these species could occur in the
[[Page 27468]]
area, the temporal and/or spatial occurrence of these species is such
that take is not expected to occur, and they are not discussed further
beyond the explanation provided here. Cuvier's beaked whale, Central
North Pacific humpback whale, Dall's porpoise, harbor seal, Pacific
white-sided dolphin, sperm whale, Stejneger's beaked whale, blue whale,
Western North Pacific gray whale, bowhead whale, North Pacific right
whale, sei whale, Northern fur seal could all occur in the project
area. We do not anticipate take of Cuvier's beaked whale, Cook Inlet
beluga whale, Dall's porpoise, Pacific white-sided dolphin, sperm
whale, Stejneger's beaked whale, blue whale, and Western North Pacific
gray whale as these species' and stocks' ranges generally do not extend
as far north as Nome. While it is possible that beluga whales from the
Eastern Chukchi Sea and Beaufort Sea stocks could occur in the project
area during the winter, spring, and fall, as both stocks migrate
between the Bering and Beaufort seas (Citta et al. 2017), animals from
the Beaufort Sea stock depart the Bering Sea in early spring, migrate
through the Chukchi Sea and into the Canadian waters of the Beaufort
Sea where they remain in the summer and fall, and return to the Bering
Sea in late fall (NMFS 2022c; i.e., are generally not expected to occur
in the project area during the planned work period). Animals from the
Eastern Chukchi Sea stock depart the Bering Sea in late spring and
early summer, migrate through the Chukchi Sea and into the western
Beaufort Sea where they remain in the summer, and return to the Bering
Sea in the fall (NMFS 2022c). Tagging data from Citta et al. (2017)
found that belugas from the Eastern Chukchi Sea and Beaufort Sea stocks
moved into the central and southern Bering Sea during winter months,
but did not move into Norton Sound (Citta et al. 2017). Therefore,
given that both stocks are already unlikely to occur in the project
area during most or all of the work period, and the animals in Citta et
al. (2017) did not enter Norton Sound, animals from these stocks are
not anticipated to be taken by project activities. Bowhead whale, North
Pacific right whale, sei whale, Northern fur seal, fin whale, Western
North Pacific humpback whale, are considered rare in Nome. While some
of the species or stocks listed herein could occur on the vessel
transit route, as noted above, we do not anticipate take of marine
mammals due to vessel transit.
In addition, the Pacific walrus may be found in Nome, AK. However,
Pacific walrus (Odobenus rosmarus divergens) are managed by the U.S.
Fish and Wildlife Service and are not considered further in this
document.
Gray Whale
Eastern North Pacific gray whales occur in the project area, though
they are not anticipated to occur in high numbers. Most whales in this
stock spend the summer and fall months feeding in the Chukchi,
Beaufort, and northwestern Bering Seas and winter in Baja California,
Mexico (Carretta et al. 2019). Eastern North Pacific gray whales have
been experiencing an Unusual Mortality Event (UME) since 2019 when
large numbers of whales began stranding from Mexico to Alaska. As of
March 14, 2023, approximately 307 gray whales have stranded in the U.S.
and 633 total throughout the U.S., Canada, and Mexico since 2019 (NOAA
2023). Preliminary necropsy results conducted on a subset of the whales
indicated that many whales showed signs of nutritional stress, however,
these findings are not consistent across all of the whales examined
(NOAA 2023). This UME is ongoing and similar to that of 1999 and 2000
when large numbers of gray whales stranded along the eastern Pacific
coast (Moore et al. 2001; Gulland et al. 2005). Oceanographic factors
limiting food availability for whales was identified as a likely cause
of the prior UME and may also be influencing the current UME (LeBouef
et al. 2000; Moore et al. 2001; Minobe 2002; Gulland et al. 2005).
Minke Whale
Minke whales occur in polar, temperate, and tropical waters
worldwide in a range extending from the ice edge in the Arctic during
the summer to near the equator during winter. Minke whales in Alaska
are considered migratory and typically occur in the Arctic during
summer months and near the equator during winter months (NMFS 2022g).
Killer Whale
Killer whales occur in every ocean in the world and are the most
widely distributed of all cetaceans. Along the west coast of North
America, killer whales occur along the entire Alaska coast (Braham and
Dahlheim 1982). Killer whales that occur in Norton Sound are likely
following seasonal movements of whales and pinnipeds.
Beluga Whale
Five beluga whale stocks occur in Alaska: The Eastern Chukchi Sea
Stock, the Beaufort Sea Stock, the Eastern Bering Sea Stock, the
Bristol Bay Stock, and the Cook Inlet Stock. While each stock is unique
and isolated from one another genetically and/or physically, there is
some crossover of the Eastern Chukchi Sea and the Eastern Bering Sea
Stock during the late summer. Beluga whales in the project area are
anticipated to be from the Eastern Bering Sea stock. The Eastern Bering
Sea stock remains in the Bering Sea and migrates south near Bristol Bay
in winter and returns north to Norton Sound and the mouth of the Yukon
River in summer (Suydam 2009; Hauser et al. 2014; Citta et al. 2017;
Lowry et al. 2019).
Beluga whales use Norton Sound during the entire open-water season,
generally moving to southern Bering Sea waters during winter due to
high ice concentrations in Norton Sound. During the spring and summer,
beluga whales tend to concentrate in the eastern half of the Sound
(Oceana and Kawerak 2014), but the whales may be seen migrating in
large numbers close to the shoreline near Nome in late autumn (ADFG
2012). Jewett (1997) stated beluga whales ``appear nearshore with the
onset of herring spawning in early summer and feed on these as well as
a wide variety of other fish congregating or migrating nearshore.''
They are often seen passing very close to the end of the Nome causeway
during the fall migration and have been occasionally spotted within the
Nome Outer Basin (USACE personal communication with Charlie Lean,
2019). Large groups of beluga have been observed in fall in front of
Cape Nome and near Topkok (Oceana and Kawerak 2014).
Norton Sound includes three biologically important areas (BIAs)
identified as important for feeding by Eastern Bering Sea belugas
(Brower et al. 2023). One of these BIAs overlaps the project area. The
BIA that overlaps the project area is active May through November,
which overlaps USACE's proposed work window (May to October). The BIA
scored a 2 for importance, intensity, data support and boundary
certainty scores, indicating that it is of moderate importance, has
moderately certain boundaries, and moderate data to support the
identification of the BIA (see Harrison et al. (2023) for additional
information about the scoring process used to identify BIAs). The BIA
was identified as having dynamic spatiotemporal variability.
Harbor Porpoise
The Bering Sea stock of harbor porpoise occurs within the project
area, ranging from throughout the Aleutian Islands and into all waters
north of Unimak Pass. The harbor porpoise
[[Page 27469]]
frequents nearshore waters and coastal embayments throughout their
range, including bays, harbors, estuaries, and fjords less than 650 ft
(198 m) deep (NMFS 2018g).
Bearded Seal
Bearded seals prefer moving ice and open water over relatively
shallow seafloors. They are closely associated with ice, preferring to
winter in the Bering Sea and summer along the pack ice edge in the
Chukchi Sea, although many summer in nearshore waters of the Beaufort
Sea (NMFS 2022a). Pupping occurs on ice floes primarily in May in the
Bering and Chukchi seas. Bearded seals feed primarily at or near the
seabed, on benthic invertebrates, and demersal fish. Spring surveys
conducted in 1999 and 2000 along the Alaska coast indicate that bearded
seals are typically more abundant 20-100 nmi (37--185 km) from shore,
except for high nearshore concentrations to the south of Kivalina
(Bengtson et al. 2000 and 2005; Simpkins et al. 2003). Many seals that
winter in the Bering Sea move north through the Bering Strait from late
April through June and spend the summer in the Chukchi Sea (Burns 1967,
1981).
Bearded seals congregate at the open water found near Cape Nome and
Sledge Island in winter and spring (Oceana and Kawerak 2014). Juvenile
bearded seals may remain in open water during the summer, feeding in
lagoons and rivers, but older individuals migrate north with the
retreating pack ice. Juvenile bearded seals have been observed hauled
out on land along lagoons and rivers in some areas of Alaska, including
in the Bering Strait region in summer to early fall (Gadamus et al.
2015; Huntington et al. 2015). In addition, satellite tracking data
obtained from juvenile bearded seals tagged in Alaska during 2014 to
2018 indicate that during the open-water period (July to October),
about half of the seals that hauled out used terrestrial sites located
south of the ice edge in Kotzebue Sound and Norton Sound whereas other
seals remained near the ice edge and hauled out on ice (Olnes et al.
2020).
Critical habitat for the bearded seal was designated in May 2022
and includes marine waters off the coast of Nome (87 FR 19180; April 1,
2022). Essential features established by NMFS for conservation of the
bearded Beringia Distinct Population Segment (DPS) include (1) Sea ice
habitat suitable for whelping and nursing, which is defined as areas
with waters 200 m or less in depth containing pack ice of at least 25
percent concentration and providing bearded seals access to hose waters
from the ice; (2) Sea ice habitat suitable as a platform for molting,
which is defined as areas with waters 200 m or less in depth containing
pack ice of at least 15 percent concentration and providing bearded
seals access to those waters from the ice, and (3) Primary prey
resources to support bearded seals: Waters 200 m or less in depth
containing benthic organisms, including epifaunal and infaunal
invertebrates, and demersal fishes.
Since June 1, 2018, elevated ice seal strandings (bearded, ringed
and spotted seals) have occurred in the Bering and Chukchi seas in
Alaska. This event was declared an Unusual Mortality Event (UME), but
is currently considered non-active and is pending closure. Given that
the UME is non-active, it is not discussed further as it relates to
bearded seals.
Ringed Seal
In winter and early spring when sea ice is at its maximum coverage,
ringed seals occur in the northern Bering Sea (including Norton Sound),
and throughout the Chukchi and Beaufort Seas. They occur as far south
as Bristol Bay in years of extensive ice coverage (Muto et al. 2022)
but generally are not abundant south of Norton Sound except in
nearshore areas (Frost 1985, 1988).
Near Nome, ringed seals often occur in the open water offshore from
Cape Nome and Safety Sound (Oceana and Kawerak 2014). Surveys conducted
in the Bering Sea in the spring of 2012 and 2013 documented numerous
ringed seals in both nearshore and offshore habitat extending south of
Norton Sound (79 FR 73010, December 9, 2014; Muto et al. 2022).
Critical habitat for the ringed seal was designated in May 2022 and
include marine waters within one specific area in the Bering, Chukchi,
and Beaufort seas including waters off the coast of Nome (87 FR 19232;
April 1, 2022). Essential features established by NMFS for conservation
of the ringed seal are (1) snow-covered sea ice habitat suitable for
the formation and maintenance of subnivean birth lairs used for
sheltering pups during whelping and nursing, which is defined as waters
3 m or more in depth (relative to Mean Lower Low Water (MLLW))
containing areas of seasonal landfast (shorefast) ice or dense, stable
pack ice, which have undergone deformation and contain snowdrifts of
sufficient depth to form and maintain birth lairs (typically at least
54 cm deep); (2) sea ice habitat suitable as a platform for basking and
molting, which is defined as areas containing sea ice of 15 percent or
more concentration in waters 3 m or more in depth (relative to MLLW);
and (3) primary prey resources to support Arctic ringed seals, which
are defined to be small, often schooling, fishes, in particular, Arctic
cod (Boreogadus saida), saffron cod (Eleginus gracilis), and rainbow
smelt (Osmerus dentex), and small crustaceans, in particular, shrimps
and amphipods.
Since June 1, 2018, elevated ice seal strandings (bearded, ringed
and spotted seals) have occurred in the Bering and Chukchi seas in
Alaska. This event was declared an Unusual Mortality Event (UME), but
is currently considered non-active and is pending closure. Given that
the UME is non-active, it is not discussed further as it relates to
ringed seals.
Spotted Seal
From late fall through spring, spotted seal habitat use is
primarily associated with seasonal sea ice. Most spotted seals spend
the rest of the year making periodic foraging trips from haulout sites
onshore or on sea ice (NMFS 2022b).
Most summer and fall concentrations of Norton Sound spotted seals
are in the eastern portion of the Sound, where herring and small cod
are more abundant. Spotted seals are reportedly more sensitive to human
disturbances than other seals and have been displaced from some haulout
and feeding areas due to such disturbance. However, spotted seals are
regularly seen at the Port of Nome and within the harbor area,
especially before or after the busy summer season, sometimes hauled out
on the beach or breakwater (USACE personal communication with Charlie
Lean, 2019). The existing Outer Basin at the Port of Nome, since the
construction of the new entrance channel and east breakwater in 2006,
has become the new river mouth and a sort of artificial lagoon of the
Snake River. Seals and other marine mammals tend to congregate there,
especially in the autumn (Oceana and Kawerak 2014). Spotted seals are
an important subsistence species for Alaska Native hunters.
Since June 1, 2018, elevated ice seal strandings (bearded, ringed
and spotted seals) have occurred in the Bering and Chukchi seas in
Alaska. This event was declared an Unusual Mortality Event (UME), but
is currently considered non-active and is pending closure. Given that
the UME is non-active, it is not discussed further.
Steller Sea Lion
Steller sea lions in the project area are anticipated to be from
the Western stock, which includes all Steller sea
[[Page 27470]]
lions originating from rookeries west of Cape Suckling (144[deg] West
longitude). The centers of abundance and distribution for western DPS
Steller sea lions are located in the Gulf of Alaska and Aleutian
Islands. At sea, Steller sea lions commonly occur near the 656-foot
(200-meter) depth contour but have been found from nearshore to well
beyond the continental shelf (Kajimura and Loughlin 1988). Sea lions
move offshore to pelagic waters for feeding excursions.
Observations suggest that Steller sea lions are becoming common in
the northern Bering Sea, including Norton Sound. Sea lions have been
spotted hauling out in small numbers at Sledge Island, about 22 miles
(mi; 35.4 km) west of Nome. Their change in range is perhaps attributed
to climate-change-driven, northward movement of pelagic fish prey
species, such as Pacific cod (USACE personal communication with Gay
Sheffield, 2018).
The nearest Steller sea lion critical habitat to the Port of Nome
is on the east shore of St. Lawrence Island, about 140 mi (225.3 km) to
the southwest. However, Steller sea lions, especially juveniles and
non-breeding males, can range through waters far beyond their primary
use areas.
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 (2018) described generalized
hearing ranges for these marine mammal hearing groups. Generalized
hearing ranges were chosen based on the approximately 65 decibel (dB)
threshold from the normalized composite audiograms, with the exception
for lower limits for low-frequency cetaceans where the lower bound was
deemed to be biologically implausible and the lower bound from Southall
et al. (2007) retained. Marine mammal hearing groups and their
associated hearing ranges are provided in Table 3.
Table 3--Marine Mammal Hearing Groups (NMFS 2018)
------------------------------------------------------------------------
Hearing group Generalized hearing range *
------------------------------------------------------------------------
Low-frequency (LF) cetaceans (baleen 7 Hz to 35 kHz.
whales).
Mid-frequency (MF) cetaceans 150 Hz to 160 kHz.
(dolphins, toothed whales, beaked
whales, bottlenose whales).
High-frequency (HF) cetaceans (true 275 Hz to 160 kHz.
porpoises, Kogia, river dolphins,
Cephalorhynchid, Lagenorhynchus
cruciger & L. australis).
Phocid pinnipeds (PW) (underwater) 50 Hz to 86 kHz.
(true seals).
Otariid pinnipeds (OW) (underwater) 60 Hz to 39 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 are typically not as broad. Generalized
hearing range chosen based on ~65 dB threshold from normalized
composite audiogram, with the exception for lower limits for LF
cetaceans (Southall et al. 2007) and PW pinniped (approximation).
The pinniped functional hearing group was modified from Southall et
al. (2007) on the basis of data indicating that phocid species have
consistently demonstrated an extended frequency range of hearing
compared to otariids, especially in the higher frequency range
(Hemil[auml] et al. 2006; Kastelein et al. 2009; Reichmuth and Holt
2013).
For more detail concerning these groups and associated frequency
ranges, please see NMFS (2018) for a review of available information.
Potential Effects of Specified Activities on Marine Mammals and Their
Habitat
This section provides a discussion of the ways in which components
of the specified activity may impact marine mammals and their habitat.
The Estimated Take of Marine Mammals section later in this document
includes a quantitative analysis of the number of individuals that are
expected to be taken by this activity. The Negligible Impact Analysis
and Determination section considers the content of this section, the
Estimated Take of Marine Mammals section, and the Proposed Mitigation
section, to draw conclusions regarding the likely impacts of these
activities on the reproductive success or survivorship of individuals
and whether those impacts are reasonably expected to, or reasonably
likely to, adversely affect the species or stock through effects on
annual rates of recruitment or survival.
Acoustic effects on marine mammals during the specified activities
can occur from vibratory and impact pile driving. The effects of
underwater noise from USACE's proposed activities have the potential to
result in Level B harassment only of marine mammals.
Description of Sound Sources
The marine soundscape is comprised of both ambient and
anthropogenic sounds. Ambient sound is defined as the all-encompassing
sound in a given place and is usually a composite of sound from many
sources both near and far (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
decibels (dB) from day to day
[[Page 27471]]
(Richardson et al. 1995). The result is that, depending on the source
type and its intensity, sound from the specified activities may be a
negligible addition to the local environment or could form a
distinctive signal that may affect marine mammals.
In-water construction activities associated with the project would
include impact and vibratory pile driving and vibratory pile removal.
The sounds produced by these activities fall into one of two general
sound types: impulsive and non-impulsive. Impulsive sounds (e.g.,
explosions, sonic booms, impact pile driving) are typically transient,
brief (less than 1 second), broadband, and consist of high peak sound
pressure with rapid rise time and rapid decay (ANSI 1986; NIOSH 1998;
NMFS 2018). Non-impulsive sounds (e.g., machinery operations such as
drilling or dredging, vibratory pile driving, underwater chainsaws, and
active sonar systems) can be broadband, narrowband or tonal, brief or
prolonged (continuous or intermittent), and typically do not have the
high peak sound pressure with raid rise/decay time that impulsive
sounds do (ANSI 1995; NIOSH 1998; NMFS 2018). The distinction between
impulsive and non-impulsive sound sources 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).
USACE plans to use two types of hammers, impact, and vibratory.
Impact hammers operate by repeatedly dropping and/or pushing a heavy
piston onto a pile to drive the pile into the substrate. Sound
generated by impact hammers is considered impulsive. Vibratory hammers
install piles by vibrating them and allowing the weight of the hammer
to push them into the sediment. Vibratory hammers produce non-
impulsive, continuous sounds. Vibratory hammering generally produces
sounds pressure levels (SPLs) 10 to 20 dB lower than 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).
The likely or possible impacts of USACE's proposed activities on
marine mammals could be generated from both non-acoustic and acoustic
stressors. Potential non-acoustic stressors include the physical
presence of the equipment, vessels, and personnel; however, we expect
that any animals that approach the project site(s) close enough to be
harassed due to the presence of equipment or personnel would be within
the Level A or Level B harassment zones from pile driving/removal and
would already be subject to harassment from the in-water activities.
Therefore, any impacts to marine mammals are expected to primarily be
acoustic in nature. Acoustic stressors include heavy equipment
operation during pile installation and removal.
Acoustic Impacts
The introduction of anthropogenic noise into the aquatic
environment from pile driving and removal equipment is the primary
means by which marine mammals may be harassed from USACE's specified
activities. In general, animals exposed to natural or anthropogenic
sound may experience physical and psychological effects, ranging in
magnitude from none to severe (Southall et al. 2007). Generally,
exposure to pile driving and removal and other construction noise has
the potential to result in auditory threshold shifts and behavioral
reactions (e.g., avoidance, temporary cessation of foraging and
vocalizing, changes in dive behavior). Exposure to anthropogenic noise
can also lead to non-observable physiological responses such as 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 and demolition 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. mother 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.
2003; Southall et al. 2007). Here we discuss physical auditory effects
(threshold shifts) followed by behavioral effects and potential impacts
on habitat.
NMFS defines a noise-induced threshold shift (TS) as a change,
usually an increase, in the threshold of audibility at a specified
frequency or portion of an individual's hearing range above a
previously established reference level (NMFS 2018). The amount of
threshold shift is customarily expressed in dB. A TS can be permanent
or temporary. As described in NMFS (2018), 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).
Permanent Threshold Shift (PTS)--NMFS defines PTS as a permanent,
irreversible increase in the threshold of audibility at a specified
frequency or portion of an individual's hearing range above a
previously established reference level (NMFS 2018). Available data from
humans and other terrestrial mammals indicate that a 40 dB threshold
shift approximates PTS onset (see Ward et al. 1958, 1959; Ward 1960;
Kryter et al. 1966; Miller 1974; Henderson et al. 2008). PTS levels for
marine mammals are estimates, because there are limited empirical data
measuring PTS in marine mammals (e.g., Kastak et al. 2008), largely due
to the fact that, for various ethical reasons, experiments involving
anthropogenic noise exposure at levels inducing PTS are not typically
pursued or authorized (NMFS 2018).
Temporary Threshold Shift (TTS)--TTS is a temporary, reversible
increase in the threshold of audibility at a specified frequency or
portion of an individual's hearing range above a previously established
reference level (NMFS 2018). Based on data from cetacean TTS
measurements (see Southall et al. 2007), a TTS of 6 dB is considered
the minimum threshold shift clearly larger than any day-to-day or
session-to-session variation in a subject's normal hearing ability
(Schlundt et al. 2000; Finneran et al. 2000, 2002). As described in
Finneran (2016), 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
[[Page 27472]]
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).
For cetaceans, published data on the onset of TTS are limited to the
captive bottlenose dolphin (Tursiops truncatus), beluga whale, harbor
porpoise, and Yangtze finless porpoise (Neophocoena asiaeorientalis),
and for pinnipeds in water, measurements of TTS are limited to harbor
seals (Phoca vitulina), elephant seals (Mirounga angustirostris), and
California sea lions (Zalophus californianus). These studies examine
hearing thresholds measured in marine mammals before and after exposure
to intense sounds. 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, 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, 2019b, 2020a, 2020b). 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
(Finneran et al. 2010; Kastelein et al. 2014; Kastelein et al. 2015a;
Mooney et al. 2009). 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) and Finneran (2018) describe the 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).
Activities for this project include impact and vibratory pile
driving and vibratory pile removal. 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
threshold shift declines.
Behavioral harassment--Exposure to noise from pile driving and
removal also has the potential to behaviorally disturb marine mammals.
Behavioral responses to sound are highly variable and context-specific
and any reactions depend on numerous intrinsic and extrinsic factors
(e.g., species, state of maturity, experience, current activity,
reproductive state, auditory sensitivity, time of day), as well as the
interplay between factors (e.g., Richardson et al. 1995; Wartzok et al.
2003; Southall et al. 2007; Weilgart 2007; Archer et al. 2010; Southall
et al. 2021). 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).
The following subsections provide examples of behavioral responses
that provide an idea of the variability in behavioral responses that
would be expected given the differential sensitivities of marine mammal
species to sound and the wide range of potential acoustic sources to
which a marine mammal may be exposed. Behavioral responses that could
occur for a given sound exposure should be determined from the
literature that is available for each species, or extrapolated from
closely related species when no information exists, along with
contextual factors. 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. 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 respiration, interference with or alteration of vocalization,
avoidance, and flight.
Pinnipeds may increase their haul out time, possibly to avoid in-
water disturbance (Thorson and Reyff 2006). 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.
Alteration of Feeding Behavior--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; Melc[oacute]n et al. 2012). In
addition, behavioral state of the animal plays a role in the type and
severity of a behavioral response, such as disruption to foraging
(e.g., Silve et al. 2016; Wensveen et al. 2017). A determination of
whether foraging
[[Page 27473]]
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. Goldbogen et al.
(2013) indicate that disruption of feeding and displacement could
impact individual fitness and health. However, for this to be true, we
would have to assume that an individual could not compensate for this
lost feeding opportunity by either immediately feeding at another
location, by feeding shortly after cessation of acoustic exposure, or
by feeding at a later time. There is no indication this is the case,
particularly since unconsumed prey would likely still be available in
the environment in most cases following the cessation of acoustic
exposure. Information on or estimates of the energetic requirements of
the individuals and the relationship between prey availability,
foraging effort and success, and the life history stage of the animal
will help better inform a determination of whether foraging disruptions
incur fitness consequences.
Avoidance--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). Avoidance is qualitatively
different from the flight response, but also differs in the magnitude
of the response (i.e., directed movement, rate of travel, etc.). Often
avoidance is temporary, and animals return to the area once the noise
has ceased. Acute avoidance responses have been observed in captive
porpoises and pinnipeds exposed to a number of different sound sources
(Kastelein et al. 2001; Finneran et al. 2003; Kastelein et al. 2006a;
Kastelein et al. 2006b; Kastelein et al. 2015b; Kastelein et al. 2015c;
Kastelein et al. 2018). Short-term avoidance of seismic surveys, low
frequency emissions, and acoustic deterrents have also been noted in
wild populations of odontocetes (Bowles et al. 1994; Goold 1996; Goold
and Fish 1998; Morton and Symonds 2002; Hiley et al. 2021) and to some
extent in mysticetes (Malme et al. 1984; McCauley et al. 2000; 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).
Forney et al. (2017) described the potential effects of noise on
marine mammal populations with high site fidelity, including
displacement and auditory masking. In cases of Western gray whales
(Eschrichtius robustus) (Weller et al. 2006) and beaked whales (Ziphius
cavirostris), anthropogenic effects in areas where they are resident or
exhibit site fidelity could cause severe biological consequences, in
part because displacement may adversely affect foraging rates,
reproduction, or health, while an overriding instinct to remain in the
area could lead to more severe acute effects. Avoidance of overlap
between disturbing noise and areas and/or times of particular
importance for sensitive species may be critical to avoiding
population-level impacts because (particularly for animals with high
site fidelity) there may be a strong motivation to remain in the area
despite negative impacts.
Flight Response--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). 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 (Evans and England 2001). There are limited data on
flight response for marine mammals in water; however, there are
examples of this response in species on land. For instance, the
probability of flight responses in Dall's sheep Ovis dalli dalli (Frid,
2003), hauled out ringed seals (Born et al. 1999), Pacific brant
(Branta bernicla nigricans), and Canada geese (B. canadensis) increased
as a helicopter or fixed-wing aircraft more directly approached groups
of these animals (Ward et al. 1999). 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 observed in marine mammals, but studies
involving fish and terrestrial animals have shown that increased
vigilance may substantially reduce feeding rates and efficiency (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).
Many animals perform vital functions, such as feeding, resting,
traveling, and socializing, on a diel cycle (24-hour cycle). Disruption
of such functions resulting from reactions to stressors such as sound
exposure are more likely to be significant if they last more than one
diel cycle or recur on subsequent days (Southall et al. 2007).
Consequently, a behavioral response lasting less than 1 day and not
recurring on subsequent days is not considered particularly severe
unless it could directly affect reproduction or survival (Southall et
al. 2007). Note that there is a difference between multi-day
substantive behavioral reactions and multi-day anthropogenic
activities. For example, just because an activity lasts for multiple
days does not necessarily mean that individual animals are either
exposed to activity-related stressors for multiple days or, further,
exposed in a manner resulting in sustained multi-day substantive
behavioral responses.
To assess the strength of behavioral changes and responses to
external sounds and SPLs associated with changes in behavior, Southall
et al. (2007) developed and utilized a severity scale, which is a 10
point scale ranging from no effect (labeled 0), effects not likely to
influence vital rates (low; labeled from 1 to 3), effects that could
affect vital rates (moderate; labeled 4 to 6), to effects that were
thought likely to influence vital rates (high; labeled 7 to 9).
Southall et al. (2021) updated the severity scale by integrating
behavioral context (i.e., survival, reproduction, and foraging) into
severity assessment. For non-impulsive sounds (i.e., similar to the
sources used during the proposed action), data suggest that exposures
of pinnipeds to sources between 90 and 140 dB re 1 [mu]Pa do not elicit
strong behavioral responses; no data were available for exposures at
higher received levels for Southall et al. (2007) to include in the
severity scale analysis. Reactions of harbor seals were the only
available data for which the responses could be ranked on the severity
scale. For reactions that were recorded, the
[[Page 27474]]
majority (17 of 18 individuals/groups) were ranked on the severity
scale as a 4 (defined as moderate change in movement, brief shift in
group distribution, or moderate change in vocal behavior) or lower; the
remaining response was ranked as a 6 (defined as minor or moderate
avoidance of the sound source).
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 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 these projects based on observations
of marine mammals during previous, similar projects.
Masking--Sound can disrupt behavior through masking, or interfering
with, an animal's ability to detect, recognize, or discriminate between
acoustic signals of interest (e.g., those used for intraspecific
communication and social interactions, prey detection, predator
avoidance, navigation; Richardson et al. 1995). Masking occurs when the
receipt of a sound is interfered with by another coincident sound at
similar frequencies and at similar or higher intensity, and may occur
whether the sound is natural (e.g., snapping shrimp, wind, waves,
precipitation) or anthropogenic (e.g., pile driving, shipping, sonar,
seismic exploration) in origin. The ability of a noise source to mask
biologically important sounds depends on the characteristics of both
the noise source and the signal of interest (e.g., signal-to-noise
ratio, temporal variability, direction), in relation to each other and
to an animal's hearing abilities (e.g., sensitivity, frequency range,
critical ratios, frequency discrimination, directional discrimination,
age or TTS hearing loss), and existing ambient noise and propagation
conditions. Masking of natural sounds can result when human activities
produce high levels of background sound at frequencies important to
marine mammals. Conversely, if the background level of underwater sound
is high (e.g., on a day with strong wind and high waves), an
anthropogenic sound source would not be detectable as far away as would
be possible under quieter conditions and would itself be masked.
Airborne Acoustic Effects--Pinnipeds that occur near the project
site could be exposed to airborne sounds associated with pile driving
and removal that have the potential to cause behavioral harassment,
depending on their distance from pile driving activities. Cetaceans are
not expected to be exposed to airborne sounds that would result in
harassment as defined under the MMPA.
Airborne noise would primarily be an issue for pinnipeds that are
swimming or hauled out near the project site within the range of noise
levels elevated above the 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 likely previously
have been `taken' because of exposure to underwater sound above the
behavioral harassment thresholds, which are generally larger than those
associated with airborne sound. Thus, the behavioral harassment of
these animals is already accounted for in these estimates of potential
take. Therefore, we do not believe that authorization of incidental
take resulting from airborne sound for pinnipeds is warranted, and
airborne sound is not discussed further.
Marine Mammal Habitat Effects
USACE's proposed construction activities could have localized,
temporary impacts on marine mammal habitat, including prey, by
increasing in-water sound pressure levels and slightly decreasing water
quality. Increased noise levels may affect acoustic habitat (see
Masking discussion above) and adversely affect marine mammal prey in
the vicinity of the project areas (see discussion below). Elevated
levels of underwater noise would ensonify the project areas where both
fishes and mammals occur and could affect foraging success.
Additionally, marine mammals may avoid the area during 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.
[[Page 27475]]
In-Water Construction Effects on Potential Foraging Habitat
The total seafloor area likely impacted by the project is
relatively small compared to the available habitat in Norton Sound and
nearby areas in the Bering Sea. Avoidance by potential prey (i.e.,
fish) of the immediate area due to the temporary loss of this foraging
habitat is possible. The duration of fish and marine mammal avoidance
of this area after pile driving stops is unknown, but a rapid return to
normal recruitment, distribution, and behavior is anticipated. Any
behavioral avoidance by fish or marine mammals of the disturbed area
would still leave significantly large areas of fish and marine mammal
foraging habitat in the nearby vicinity.
A temporary and localized increase in turbidity near the seafloor
would occur in the immediate area surrounding the area where piles 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). Turbidity and sedimentation effects are
expected to be short-term, minor, and localized. 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. Therefore, we expect the impact from increased turbidity
levels to be discountable to marine mammals. Furthermore, pile driving
and removal at the project site would not obstruct movements or
migration of marine mammals.
Effects on Potential Prey
Sound may affect marine mammals through impacts on the abundance,
behavior, or distribution of prey species (e.g., fish). Marine mammal
prey varies by species, season, and location. 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 and Mann 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 that are especially strong and/or intermittent
low-frequency sounds, and behavioral responses such as flight or
avoidance are the most likely effects. Short duration, sharp sounds can
cause overt or subtle changes in fish behavior and local distribution.
The reaction of fish to noise depends on the physiological state of the
fish, past exposures, motivation (e.g., feeding, spawning, migration),
and other environmental factors. Hastings and Popper (2005) identified
several studies that suggest fish may relocate to avoid certain areas
of sound energy. Additional studies have documented effects of pile
driving on fish; 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).
SPLs of sufficient strength have been known to cause injury to fish
and fish mortality. However, in most fish species, hair cells in the
ear continuously regenerate and loss of auditory function likely is
restored when damaged cells are replaced with new cells. Halvorsen et
al. (2012a) showed that a TTS of 4-6 dB was recoverable within 24 hours
for one species. Impacts would be most severe when the individual fish
is close to the source and when the duration of exposure is long.
Injury caused by barotrauma can range from slight to severe and can
cause death, and is most likely for fish with swim bladders. Barotrauma
injuries have been documented during controlled exposure to impact pile
driving (Halvorsen et al. 2012b; Casper et al. 2013).
The most likely impact to fishes from pile driving activities at
the project area would be temporary behavioral avoidance of the area.
The duration of fish avoidance of this area after pile driving stops is
unknown, but a rapid return to normal recruitment, distribution, and
behavior is anticipated.
Construction activities have the potential to have adverse impacts
on forage fish in the project area in the form of increased turbidity.
Forage fish form a significant prey base for many marine mammal species
that occur in the project area. Turbidity within the water column has
the potential to reduce the level of oxygen in the water and irritate
the gills of prey fish in the proposed project area. However, fish in
the proposed project area would be able to move away from and avoid the
areas where increase turbidity may occur. Given the limited area
affected and ability of fish to move to other areas, any effects on
forage fish are expected to be minor or negligible.
In summary, given the short daily duration of sound associated with
individual pile driving and removal events and the relatively small
areas being affected, pile driving and removal activities associated
with the proposed actions 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
activities are not likely to have more than short-term adverse effects
on any prey habitat or populations of prey species. Further, any
impacts to marine mammal habitat are not expected to result in
significant or long-term consequences for individual marine mammals, or
to contribute to 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 this IHA, which will inform both
NMFS' consideration of ``small numbers,'' and the negligible impact
determinations.
Harassment is the only type of take expected to result from these
activities. Except with respect to certain activities not pertinent
here, section 3(18) of the MMPA defines ``harassment'' as any act of
pursuit, torment, or annoyance, which (i) has the potential to injure a
marine mammal or marine mammal stock in the wild (Level A harassment);
or (ii) has the potential to disturb a marine mammal or marine mammal
stock in the wild by causing disruption of behavioral patterns,
including, but not limited to, migration, breathing, nursing, breeding,
feeding, or sheltering (Level B harassment).
Authorized takes would be by Level B harassment only, in the form
of disruption of behavioral patterns and/or
[[Page 27476]]
TTS for individual marine mammals resulting from exposure to
construction activities. Based on the nature of the activity and the
anticipated effectiveness of the mitigation measures (i.e.,
implementation of shutdown zones) discussed in detail below in the
Proposed Mitigation section, Level A harassment is neither anticipated
nor proposed to be authorized.
As described previously, no serious injury or mortality is
anticipated or proposed to be authorized for this activity. Below we
describe how the proposed take numbers are estimated.
For acoustic impacts, generally speaking, we estimate take by
considering: (1) acoustic thresholds above which NMFS believes the best
available science indicates marine mammals will be behaviorally
harassed or incur some degree of permanent hearing impairment; (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 Thresholds
NMFS recommends the use of acoustic thresholds 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 PTS of some degree (equated to Level A
harassment).
Level B Harassment--Though significantly driven by received level,
the onset of behavioral disturbance from anthropogenic noise exposure
is also informed to varying degrees by other factors related to the
source or exposure context (e.g., frequency, predictability, duty
cycle, duration of the exposure, signal-to-noise ratio, distance to the
source), the environment (e.g., bathymetry, other noises in the area,
predators in the area), and the receiving animals (hearing, motivation,
experience, demography, life stage, depth) and can be difficult to
predict (e.g., Southall et al. 2007, 2021; Ellison et al. 2012). Based
on what the available science indicates and the practical need to use a
threshold based on a metric that is both predictable and measurable for
most activities, NMFS typically uses a generalized acoustic threshold
based on received level to estimate the onset of behavioral harassment.
NMFS generally predicts that marine mammals are likely to be
behaviorally harassed in a manner considered to be Level B harassment
when exposed to underwater anthropogenic noise above root-mean-squared
pressure received levels (RMS SPL) of 120 dB (referenced to 1
micropascal (re 1 [mu]Pa)) for continuous (e.g., vibratory pile-
driving) and above RMS SPL 160 dB re 1 [mu]Pa for non-explosive
impulsive (e.g., seismic airguns) or intermittent (e.g., scientific
sonar) sources. Generally speaking, Level B harassment take estimates
based on these behavioral harassment thresholds are expected to include
any likely takes by TTS as, in most cases, the likelihood of TTS occurs
at distances from the source less than those at which behavioral
harassment is 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.
USACE's activity includes the use of continuous (vibratory pile
driving) and impulsive (impact pile driving) sources, and therefore the
RMS SPL thresholds of 120 and 160 dB re 1 [mu]Pa are applicable.
Level A harassment--NMFS' Technical Guidance for Assessing the
Effects of Anthropogenic Sound on Marine Mammal Hearing (Version 2.0)
(Technical Guidance, 2018) identifies dual criteria to assess auditory
injury (Level A harassment) to five different marine mammal groups
(based on hearing sensitivity) as a result of exposure to noise from
two different types of sources (impulsive or non-impulsive). USACE's
proposed activity includes the use of impulsive (impact pile driving)
and non-impulsive (vibratory pile driving) sources.
These thresholds are provided in the Table 4. The references,
analysis, and methodology used in the development of the thresholds are
described in NMFS' 2018 Technical Guidance, which may be accessed at:
<a href="http://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-acoustic-technical-guidance">www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-acoustic-technical-guidance</a>.
Table 4--Thresholds Identifying the Onset of Permanent Threshold Shift
--------------------------------------------------------------------------------------------------------------------------------------------------------
PTS onset acoustic thresholds \*\ (received level)
Hearing group -------------------------------------------------------------------------------------------------------------------
Impulsive Non-impulsive
--------------------------------------------------------------------------------------------------------------------------------------------------------
Low-Frequency (LF) Cetaceans........ Cell 1: Lpk,flat: 219 dB; LE,LF,24h: 183 dB......................... Cell 2: LE,LF,24h: 199 dB.
Mid-Frequency (MF) Cetaceans........ Cell 3: Lpk,flat: 230 dB; LE,MF,24h: 185 dB......................... Cell 4: LE,MF,24h: 198 dB.
High-Frequency (HF) Cetaceans....... Cell 5: Lpk,flat: 202 dB; LE,HF,24h: 155 dB......................... Cell 6: LE,HF,24h: 173 dB.
Phocid Pinnipeds (PW) (Underwater).. Cell 7: Lpk,flat: 218 dB; LE,PW,24h: 185 dB......................... Cell 8: LE,PW,24h: 201 dB.
Otariid Pinnipeds (OW) (Underwater). Cell 9: Lpk,flat: 232 dB; LE,OW,24h: 203 dB......................... Cell 10: LE,OW,24h: 219 dB.
--------------------------------------------------------------------------------------------------------------------------------------------------------
* Dual metric acoustic thresholds for impulsive sounds: Use whichever results in the largest isopleth for calculating PTS onset. If a non-impulsive
sound has the potential of exceeding the peak sound pressure level thresholds associated with impulsive sounds, these thresholds should also be
considered.
Note: Peak sound pressure (Lpk) has a reference value of 1 [micro]Pa, and cumulative sound exposure level (LE) has a reference value of 1[micro]Pa\2\s.
In this Table, thresholds are abbreviated to reflect American National Standards Institute standards (ANSI 2013). However, peak sound pressure is
defined by ANSI as incorporating frequency weighting, which is not the intent for this Technical Guidance. Hence, the subscript ``flat'' is being
included to indicate peak sound pressure should be flat weighted or unweighted within the generalized hearing range. The subscript associated with
cumulative sound exposure level thresholds indicates the designated marine mammal auditory weighting function (LF, MF, and HF cetaceans, and PW and OW
pinnipeds) and that the recommended accumulation period is 24 hours. The 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 acoustic thresholds will be exceeded.
[[Page 27477]]
Ensonified Area
Here, we describe operational and environmental parameters of the
activity that are used in estimating the area ensonified above the
acoustic thresholds, including source levels and transmission loss
coefficient.
The sound field in the project area is the existing background
noise plus additional construction noise from the proposed project.
Marine mammals are expected to be affected via sound generated by the
primary components of the project (i.e., pile driving and removal). The
maximum (underwater) area ensonified above the thresholds for
behavioral harassment referenced above is 752 km\2\ (290 mi\2\), and
the calculated distance to the farthest behavioral harassment isopleth
is approximately 21.5 km (13.4 mi).
The project includes vibratory pile installation and removal and
impact pile driving. Source levels for these activities are based on
reviews of measurements of the same or similar types and dimensions of
piles available in the literature. Source levels for each pile size and
activity are presented in Table 5. Source levels for vibratory
installation and removal of piles of the same diameter are assumed to
be the same.
Table 5--Sound Source Levels for Pile Driving Activities
--------------------------------------------------------------------------------------------------------------------------------------------------------
Vibratory sound source levels Impact sound source levels \1\
Pile type -----------------------------------------------------------------------------------------------------------------------
SPLRMS SEL Peak Literature source SPLRMS SEL Peak Literature source
--------------------------------------------------------------------------------------------------------------------------------------------------------
Temporary template piles (Pipe 154.0 144.0 N/A Caltrans (2020).... 189.0 178.0 203.0 Caltrans (2015).
piles <=24'').
Alternate Temporary template 150.0 147.0 165.0 Caltrans (2020).... 178.0 166.0 200.0 Caltrans (2020).
piles (H-piles 14'').
Anchor piles (14'' HP14x89 or 150.0 147.0 165.0 Caltrans (2020).... 178.0 166.0 200.0 Caltrans (2020).
similar).
Sheet piles (20'' PS31 or 160.7 161.1 171.5 PND (2016, 2020)... 189.0 179.0 205.0 Caltrans (2015).
similar).
Fender piles (Pipe piles 36'').. 170.0 159.0 191.0 Caltrans (2015).... 193.0 183.0 210.0 Caltrans (2015).
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ USACE anticipates that all piles would be installed/removed using a vibratory hammer. However, if conditions prevent successful installation with a
vibratory hammer, USACE would use an impact hammer to complete installation.
Transmission loss (TL) is the decrease in acoustic intensity as an
acoustic pressure wave propagates out from a source. TL parameters vary
with frequency, temperature, sea conditions, current, source and
receiver depth, water depth, water chemistry, and bottom composition
and topography. The general formula for underwater
TL is:
TL = B * Log10 (R1/R2),
where
TL = transmission loss in dB
B = transmission loss coefficient
R1 = the distance of the modeled SPL from the driven pile, and
R2 = the distance from the driven pile of the initial measurement
Absent site-specific acoustical monitoring with differing measured
transmission loss, a practical spreading value of 15 is used as the
transmission loss coefficient in the above formula. Site-specific
transmission loss data for the Port of Nome 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 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, 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 PTS. Inputs used in the optional User Spreadsheet tool, and the
resulting estimated isopleths, are reported below.
Table 6--User Spreadsheet Inputs (Source Levels Provided in Table 5)
----------------------------------------------------------------------------------------------------------------
Strikes per
Pile type Installation/ Minutes per pile pile (impact) Piles per day
removal (vibratory) \1\ \1\
----------------------------------------------------------------------------------------------------------------
Temporary template piles (Pipe Installation....... 10................. 20 20.
piles <=24'').
Removal............ 10................. .............. 20.
(Alternate) Temporary template Installation....... 10................. 20 (20).
piles (H-piles 14'').
Removal............ (10)............... .............. (20).
Anchor piles (14'' HP14x89 or Installation....... 10................. 20 20.
similar).
Sheet piles (20'' PS31 or Installation....... 10 (20 per pair)... 10 28 (14 pairs).
similar).
Fender piles (Pipe piles 36'')... Installation....... 10................. 20 12.
----------------------------------------------------------------------------------------------------------------
\1\ USACE anticipates that all piles would be installed/removed using a vibratory hammer. However, if conditions
prevent successful installation with a vibratory hammer, USACE would use an impact hammer to complete
installation.
[[Page 27478]]
Table 7--Level A Harassment and Level B Harassment Isopleths From Vibratory and Impact Pile Driving
----------------------------------------------------------------------------------------------------------------
Level A harassment isopleths (m) Level B
Pile type ------------------------------------------------------- harassment
LF MF HF PW OW isopleth (m)
----------------------------------------------------------------------------------------------------------------
VIBRATORY
----------------------------------------------------------------------------------------------------------------
Temporary template piles (Pipe piles 5 <1 7 3 <1 1,848
<=24'').................................
(Alternate) Temporary template piles (H- 3 <1 4 2 <1 1,000
piles 14'').............................
Anchor piles (14'' HP14x89 or similar)... 3 <1 4 2 <1 1,000
Sheet piles (20'' PS31 or similar)....... 18 2 27 11 <1 5,168
Fender piles (Pipe piles 36'')........... 43 4 64 26 2 21,544
----------------------------------------------------------------------------------------------------------------
IMPACT
----------------------------------------------------------------------------------------------------------------
Temporary template piles (Pipe piles 252 9 300 135 10 858
<=24'').................................
(Alternate) Temporary template piles (H- 40 1 48 21 2 159
piles 14'').............................
Anchor piles (14'' HP14x89 or similar)... 40 1 48 21 2 159
Sheet piles (20'' PS31 or similar)....... 231 8 276 124 9 858
Fender piles (Pipe piles 36'')........... 386 14 459 206 15 1,585
----------------------------------------------------------------------------------------------------------------
Marine Mammal Occurrence and Take Calculation and Estimation
In this section we provide information about the occurrence of
marine mammals, including density or other relevant information that
will inform the take calculations. We describe how the information
provided is synthesized to produce a quantitative estimate of the take
that is reasonably likely to occur and proposed for authorization. A
summary of proposed take, including as a percentage of population for
each of the species, is shown in Table 9.
Gray Whale
Various gray whale density and occurrence information is available
for the Bering, Chukchi, and Beaufort Seas (e.g., Clarke et al. 2020;
Ferguson et al. 2018a). Ljungblad et al. (1982) and Ljungblad and Moore
(1983) summarized aerial surveys conducted in the Bering Sea including
the waters of Norton Sound in the early 1980s. Both reported gray
whales feeding in large numbers in Norton Sound and waters near St.
Lawrence Island. During the Chukchi Sea Environmental Studies Program
(CSESP) a large number of gray whales (n = 55, including 2 calves) were
observed feeding in late July approximately 130 km from the Port of
Nome (Lomac-MacNair et al. 2022). During the Quintillion subsea fiber
optic cable project three sightings of eight total gray whales were
detected within 60 km of Nome, four during July and four during
November 2016 (Blees et al. 2017).
However, NMFS was unable to locate data describing frequency of
gray whale occurrence or density within the project area or in Norton
Sound more generally. USACE conducted monitoring at the project site on
19 calendar days during 2019 and 2021. USACE did not detect gray whales
during that monitoring, but they are known to occur in Norton Sound and
have been sighted during previous aerial line-transect surveys in
Norton Sound (personal communication; Megan Ferguson, February 21,
2023).
NMFS estimates that a gray whale or group of gray whales may enter
the project area periodically throughout the duration of the
construction period, averaging one gray whale per week. Therefore,
given the limited information in the project area to otherwise inform a
take estimate, NMFS proposes to authorize 12 takes by Level B
harassment of gray whale.
USACE is planning to implement shutdown zones that extend to or
exceed the Level A harassment isopleth for all activities. Therefore,
especially in combination with the already low frequency of gray whales
entering the area, implementation of the proposed shutdown zones is
expected to eliminate the potential for take by Level A harassment of
gray whale. Therefore, USACE did not request take by Level A harassment
of gray whale, nor is NMFS is proposing to authorize any.
Minke Whale
Various minke whale density and occurrence information is available
for the Bering, Chukchi, and Beaufort Seas (e.g., Clarke et al. 2020;
Moore et al. 2002). During CSESP surveys (2008-2014), minke whales were
observed near the Port of Nome (Lomac-MacNair et al. 2022). No minke
whales were seen during monitoring efforts at Nome during the 2016
Quintillion subsea fiber optic cable project (Blees et al. 2017). NMFS
was unable to locate data describing frequency of minke whale
occurrence, group size, or density within the project area or in Norton
Sound more generally. USACE did not detect minke whales during its 2019
and 2021 monitoring, but they are known to occur in Norton Sound and
have been sighted during previous aerial line-transect surveys in
Norton Sound (personal communication; Megan Ferguson, February 21,
2023).
NMFS estimates that a minke whale may enter the project area
periodically throughout the duration of the construction period,
averaging one minke whale per week. Therefore, given the limited
information in the project area to otherwise inform a take estimate,
NMFS proposes to authorize 12 takes by Level B harassment of minke
whale.
USACE is planning to implement shutdown zones that extend to or
exceed the Level A harassment isopleth for all activities. Therefore,
especially in combination with the already low frequency of minke
whales entering the area, implementation of the proposed shutdown zones
is expected to eliminate the potential for take by Level A harassment
of minke whale. Therefore, USACE did not request take by Level A
harassment of minke whale, nor is NMFS is proposing to authorize any.
Killer Whale
Limited information regarding killer whale occurrence in the Nome
area is available. Waite et al. (2002) estimated 391 (95 percent CI =
171-894) killer whales of all types in the southeastern Bering Sea
using line-transect methods and indicates that density of killer whales
is also high in this area (.0025 whales per km\2\). During the
Quintillion subsea fiber optic cable project, a single killer whale was
recorded within 60 km of Nome during July 2016 (Blees et al. 2017).
USACE did not detect killer
[[Page 27479]]
whales during its 2019 and 2021 monitoring.
NMFS estimates that 2 groups of 15 killer whales may enter the
project area over the duration of the construction period. Therefore,
given the limited information in the project area to otherwise inform a
take estimate, NMFS conservatively proposes to authorize 30 takes by
Level B harassment of killer whale (2 groups of 15 animals). NMFS
anticipates that these takes could occur to the Eastern North Pacific
Alaska Resident stock, the Eastern North Pacific Gulf of Alaska,
Aleutian Islands, and Bering Sea Transient stock, or some combination
of the two.
USACE is planning to implement shutdown zones that extend to or
exceed the Level A harassment isopleth for all activities. Therefore,
especially in combination with the already low occurrence of killer
whales in the area, implementation of the proposed shutdown zones is
expected to eliminate the potential for take by Level A harassment of
killer whale. Therefore, USACE did not request take by Level A
harassment of killer whale, nor is NMFS is proposing to authorize any.
Harbor Porpoise
Moore et al. (2002) reported density estimates for harbor porpoise
derived from vessel survey data collected on visual line transect
surveys for cetaceans in the central-eastern Bering Sea (CEBS) in July
and August 1999 and in the southeastern Bering Sea (SEBS) in June and
July 2000. Harbor porpoise were seen throughout the coastal (shore to
50 m) and middle shelf (50-100 m) zones in the SEBS with sighting in
the coastal zone over four times that of the middle shelf zone.
Relatively few harbor porpoise were reported in the CEBS. Density for
harbor porpoise in the CEBS was 0.0035 porpoise/km\2\ and in the SEBS
was 0.012 animals/km\2\. During the Quintillion subsea fiber optic
cable project four sightings of 8 total harbor porpoise were recorded
within 60 km of Nome, four each during July and August 2016 (Blees et
al. 2017). USACE detected one harbor porpoise during its 2019 and 2021
monitoring.
Clarke et al. (2019) indicated a maximum group size of four harbor
porpoise in the Distribution and Relative Abundance of Marine Mammals
in the Eastern Chukchi and Western Beaufort Seas, 2018 Annual Report
(Clarke et al. 2019). NMFS estimates that one group of four harbor
porpoise may enter the project area every other week during the
construction period. Therefore, given the limited information in the
project area to otherwise inform a take estimate, NMFS conservatively
proposes to authorize 24 takes by Level B harassment of harbor porpoise
(1 groups of 4 animals x 6 weeks).
USACE is planning to implement shutdown zones that extend to or
exceed the Level A harassment isopleth for all activities, and it did
not request take by Level A harassment of harbor porpoise. For some
activities (i.e., impact driving of fender piles), the shutdown zones
extends farther than Protected Species Observers (PSO) may be able to
reliably detect harbor porpoise. However, given the portion of the zone
within which PSOs could reliably detect a harbor porpoise, the
infrequency of harbor porpoise observations during USACE's 2019 and
2021 monitoring, and harbor porpoise sensitivity to noise, NMFS does
not anticipate take by Level A harassment of harbor porpoise, nor is
NMFS is proposing to authorize any.
Beluga Whale
Beluga whales use Norton Sound during the entire open-water season,
generally moving to southern Bering Sea waters during winter due to
high ice concentrations in Norton Sound. During the spring and summer,
beluga whales tend to concentrate in the eastern half of the Sound
(Oceana and Kawerak 2014), but the whales may be seen migrating in
large numbers close to the shoreline near Nome in late autumn (ADFG
2012). Jewett (1997) stated beluga whales ``appear nearshore with the
onset of herring spawning in early summer and feed on these as well as
a wide variety of other fish congregating or migrating nearshore.''
They are often seen passing very close to the end of the Nome causeway
during the fall migration and have been occasionally spotted within the
Nome Outer Basin (USACE personal communication with Charlie Lean,
2019). Large groups of beluga have been observed in fall in front of
Cape Nome and near Topkok (Oceana and Kawerak 2014). In 2012, two
beluga whales from the Eastern Bering Sea stock were tagged near Nome.
Prior to being tagged both were known to range throughout Norton Sound.
The first of the two tagged belugas left Norton Sound in early November
and the second departed in mid-November (Citta et al. 2017). No beluga
whales were seen during monitoring efforts at Nome during the 2016
Quintillion subsea fiber optic cable project (Blees et al. 2017).
USACE detected 129 beluga whales (n = 75 during September 2019, n =
45 during September 2021, and n = 12 during October 2021) over 154
hours of monitoring on 19 days in 2019 and 2021, making beluga whales
the most frequently detected species during that monitoring period.
Assuming that USACE would conduct a 12-hour work day on average, the
pre-activity monitoring suggests a detection rate of approximately 10
beluga whales per day.
NMFS conservatively estimates that 15 beluga whales may enter the
project area per day throughout the construction period. While 15 is
higher than the detection rate reported from USACE's 2019 and 2021
monitoring, the monitoring was conducted by one or two PSOs, and
therefore, only a fraction of the area that would comprise the Level B
harassment zones for this project was observed. Therefore, NMFS
conservatively proposes to authorize 1,275 takes by Level B harassment
of beluga whale (15 animals x 85 days).
USACE is planning to implement shutdown zones that extend to or
exceed the Level A harassment isopleth for all activities. Therefore,
implementation of the proposed shutdown zones is expected to eliminate
the potential for take by Level A harassment of beluga whale.
Therefore, USACE did not request take by Level A harassment of beluga
whale, nor is NMFS is proposing to authorize any.
Steller Sea Lion
USACE did not observe any Steller sea lions during the 2019 and
2021 monitoring. Additional data regarding Steller sea lion occurrence
in the Nome area is very limited. However, Steller sea lions are known
to occur in the area, and observations suggest that Steller sea lions
are becoming common in the northern Bering Sea, including Norton Sound.
Sea lions have been detected hauling out in small numbers at Sledge
Island, about 22 mi (35.4 km) west of Nome. Their change in range is
perhaps attributed to climate-change-driven, northward movement of
pelagic fish prey species, such as Pacific cod (USACE personal
communication with Gay Sheffield, 2018). Further, during the
Quintillion subsea fiber optic cable project in August 2016, a Steller
sea lion was detected within 60 km of Nome (Blees et al. 2017).
NMFS conservatively estimates that one Steller sea lion may enter
the project area per day during the construction period. Therefore,
given the limited information in the project area to otherwise inform a
take estimate, NMFS conservatively proposes to authorize 85 takes by
Level B harassment of Steller sea lion (1 animal x 85 days).
[[Page 27480]]
USACE is planning to implement shutdown zones that extend to or
exceed the Level A harassment isopleth for all activities. Therefore,
especially in combination with the already low occurrence of Steller
sea lion in the area, implementation of the proposed shutdown zones is
expected to eliminate the potential for take by Level A harassment of
Steller sea lion. Therefore, USACE did not request take by Level A
harassment of Steller sea lion, nor is NMFS is proposing to authorize
any.
Spotted Seal
Most summer and fall concentrations of Norton Sound spotted seals
are in the eastern portion of the Sound, where herring and small cod
are more abundant. However, spotted seals are regularly seen at the
Port of Nome and within the harbor area, especially before or after the
busy summer season, sometimes hauled out on the beach or breakwater
(USACE personal communication with Charlie Lean, 2019). Since the
construction of the new entrance channel and east breakwater in 2006,
the existing Outer Basin at the Port of Nome has become the new river
mouth and a sort of artificial lagoon of the Snake River. Seals and
other marine mammals tend to congregate there, especially in the autumn
(Oceana and Kawerak 2014). During the Quintillion subsea fiber optic
cable project, a total of 10 spotted seals were recorded within 60 km
of Nome during July and August 2016 (Blees et al. 2017).
USACE detected 23 spotted seals during its 2019 and 2021
monitoring, making spotted seals the second most frequently detected
species during that monitoring. Assuming that USACE would conduct a 12-
hour work day on average, the pre-activity monitoring suggests a
detection rate of approximately two spotted seals per day.
NMFS conservatively estimates that 20 spotted seals may enter the
project area per day throughout the construction period. While 20 is
higher than the detection rate reported from USACE's 2019 and 2021
monitoring, the monitoring was conducted by one or two PSOs, and
therefore, only a fraction of the area that would comprise the Level B
harassment zones for this project was observed. Therefore, NMFS
conservatively proposes to authorize 1,700 takes by Level B harassment
of spotted seals (20 animals x 85 days).
USACE is planning to implement shutdown zones that extend to or
exceed the Level A harassment isopleth for all activities. Therefore,
implementation of the proposed shutdown zones is expected to eliminate
the potential for take by Level A harassment of spotted seal.
Therefore, USACE did not request take by Level A harassment of spotted
seal, nor is NMFS is proposing to authorize any.
Ringed Seal
Near Nome, ringed seals often occur in the open water offshore from
Cape Nome and Safety Sound (Oceana and Kawerak 2014). Surveys conducted
in the Bering Sea in the spring of 2012 and 2013 documented numerous
ringed seals in both nearshore and offshore habitat extending south of
Norton Sound (79 FR 73010, December 9, 2014; Muto et al. 2022). During
the Quintillion subsea fiber optic cable project two ringed seals were
recorded within 60 kilometers (km) of Nome during July 2016 (Blees et
al. 2017). Braham et al. (1984) reported ringed seal densities ranging
from 0.005 to 0.017 in the Bering Sea. Bengtson et al. (2005) reported
ringed seal densities ranging from 1.62 to 1.91 in the Alaskan Chukchi
Sea. Aerts et al. (2013) report combined ringed and spotted seal
densities of 0.011 to 0.091 in the Northeastern Chukchi Sea. USACE did
not detect ringed seals during its 2019 and 2021 monitoring.
Neither USACE nor NMFS were able to locate more recent occurrence
or density information for ringed seals in or near Norton Sound, beyond
that described above. Therefore, USACE estimated the density of ringed
seals in the project area to be 0.02 seals/km\2\, slightly higher than
the dated, but most local, Braham et al. (1984) Bering Sea densities.
Unable to locate more recent data for the area, NMFS concurs with this
estimate.
To calculate take by Level B harassment of ringed seal, USACE
multiplied the estimated density (0.02 animals/km\2\) by the area of
the Level B harassment zone for a given activity by the number of days
that activity would occur (Table 8). NMFS concurs with this method and
is conservatively proposing to authorize 92 takes by Level B harassment
of ringed seal.
Table 8--Area of Level B Harassment Zones and Number of Days on Which Each Activity Would Occur
----------------------------------------------------------------------------------------------------------------
Temporary
template piles Anchor piles Sheet piles Fender piles
----------------------------------------------------------------------------------------------------------------
Number of Days of Activity...................... \a\ 24 2 57 2
Level B Harassment Zone (km\2\)................. 8.41 2.96 50.46 751.9
----------------------------------------------------------------------------------------------------------------
\a\ Installation and removal.
USACE is planning to implement shutdown zones that extend to or
exceed the Level A harassment isopleth for all activities. Therefore,
implementation of the proposed shutdown zones is expected to eliminate
the potential for take by Level A harassment of ringed seal. Therefore,
USACE did not request take by Level A harassment of ringed seal, nor is
NMFS is proposing to authorize any.
Ribbon Seal
Ribbon seals occur in the Bering Sea from late March to early May.
From May to mid-July the ice recedes, and ribbon seals move further
north into the Bering Strait and the southern part of the Chukchi Sea
(Muto et al. 2022). An estimated 6,000-25,000 ribbon seals from the
eastern Bering Sea occur in the Chukchi Sea during the spring open-
water period (Boveng et al. 2017). Braham et al. (1984) reported a
maximum density of 0.002 seals/km\2\ from 1976 aerial surveys of ribbon
seals in the Bering Sea. USACE did not detect ribbon seals during its
2019 and 2021 monitoring.
To calculate take by Level B harassment of ribbon seal, USACE
multiplied the estimated density (0.002 animals/km\2\) by the area of
the Level B harassment zone for a given activity by the number of days
that activity would occur (Table 8). NMFS concurs with this method and
is conservatively proposing to authorize 9 takes by Level B harassment
of ribbon seal.
USACE is planning to implement shutdown zones that extend to or
exceed the Level A harassment isopleth for all activities. Therefore,
especially in combination with the already low occurrence of ribbon
seals in the area, implementation of the proposed shutdown zones is
expected to eliminate the potential for take by Level
[[Page 27481]]
A harassment of ribbon seal. Therefore, USACE did not request take by
Level A harassment of ribbon seal, nor is NMFS is proposing to
authorize any.
Bearded Seal
Braham et al. (1984) reported bearded seal densities ranging from
0.006 and 0.782 seals per km\2\ in the Bering Sea. Bengtson et al.
(2005) reported bearded seal densities ranging from 0.07 to 0.14 seals/
km\2\ in the Alaskan Chukchi Sea. In the spring of 2012 and 2013, U.S.
and Russian researchers conducted aerial abundance and distribution
surveys over the entire ice-covered portions of the Bering Sea
(Moreland et al. 2013). Conn et al. (2014), using a sub-sample of the
data collected from the U.S. portion of the Bering Sea in 2012,
calculated a posterior mean density estimate using an effective study
area of 767,114 km\2\ of 0.39 bearded seals/km\2\ (95 percent CI 0.32-
0.47). Results from 2006 helicopter transect surveys over a 279,880
km\2\ subset of the study area calculated density estimates of 0.22
bearded seals/km\2\ (95 percent CI 0.12-0.61; Ver Hoef et al. 2013).
USACE detected one bearded seal during its 2019 and 2021 monitoring.
To calculate take by Level B harassment of bearded seal, USACE
multiplied the estimated density (0.39 animals/km\2\) by the area of
the Level B harassment zone for a given activity by the number of days
that activity would occur (Table 8). NMFS concurs with this method and
is proposing to conservatively authorize 2,554 takes by Level B
harassment of bearded seal.
USACE is planning to implement shutdown zones that extend to or
exceed the Level A harassment isopleth for all activities. Therefore,
implementation of the proposed shutdown zones is expected to eliminate
the potential for take by Level A harassment of bearded seal.
Therefore, USACE did not request take by Level A harassment of bearded
seal, nor is NMFS is proposing to authorize any.
Table 9--Proposed Take and Proposed Take as a Percentage of Stock Abundance
----------------------------------------------------------------------------------------------------------------
Proposed take
Proposed take as a
Species Stock (Level B Stock percentage of
harassment abundance stock
only) abundance
----------------------------------------------------------------------------------------------------------------
Bearded Seal.......................... Beringia................ 2,554 N/A N/A
Ribbon Seal........................... Unidentified............ 9 184,697 <1
Ringed Seal........................... Arctic.................. 92 N/A N/A
Spotted Seal.......................... Bering.................. 1,700 461,625 <1
Steller sea lion...................... Western................. 85 \b\ 52,932 <1
Beluga whale.......................... Eastern Bering Sea...... 1,275 12,269 10
Harbor Porpoise....................... Bering Sea.............. 24 N/A N/A
Killer Whale.......................... Eastern North Pacific 30 \a\ 1,920 2
Alaska Resident.
Eastern North Pacific \a\ 587 5
Gulf of Alaska,
Aleutian Islands and
Bering Sea Transient.
Minke Whale........................... Alaska.................. 12 N/A N/A
Gray Whale............................ Eastern North Pacific... 12 26,960 <1
----------------------------------------------------------------------------------------------------------------
N/A = Not applicable.
\a\ Nest is based upon counts of individuals identified from photo-ID catalogs.
\b\ Nest is best estimate of counts, which have not been corrected for animals at sea during abundance surveys.
Effects of Specified Activities on Subsistence Uses of Marine Mammals
The availability of the affected marine mammal stocks or species
for subsistence uses may be impacted by this activity. The subsistence
uses that may be affected and the potential impacts of the activity on
those uses are described below. Measures included in this IHA to reduce
the impacts of the activity on subsistence uses are described in the
Proposed Mitigation section. Last, the information from this section
and the Proposed Mitigation section is analyzed to determine whether
the necessary findings may be made in the Unmitigable Adverse Impact
Analysis and Determination section.
During open-water months (May through October) species in the area
harvested for subsistence uses include beluga whale, ice seals (ringed
seal, bearded seal, ribbon seal, and spotted seal), and Steller sea
lion.
Eastern Bering Sea belugas are an important nutritional and
cultural resource to Alaska Natives and are harvested by more than 20
communities in Norton Sound and the Yukon (Ferguson et al. 2018b). The
Eastern Bering Sea stock of beluga whales are harvested by nine Norton
Sound communities (Elim, Golovin, Koyuk, Nome/Council, Saint Michael,
Shaktoolik, Stebbins, Unalakleet, and White Mountain; NSB 2022). Frost
and Suydam (2010) reported that of the nine communities, the highest
annual harvest is at Koyuk (n=55) and an annual average of 0.6 belugas
are harvested by Nome. Nome hunters harvest beluga on the west side of
Cape Nome, all the way from Cape Nome to Nome, and from Nome west to
Sledge Island (Oceana and Kawerak 2014). Beluga subsistence areas
between spring and fall are documented between Cape Nome to Cape Darby
and around the east coastline of Norton Sound to Stewart Island (Oceana
and Kawerak 2014). Beluga whales have been traditionally hunted in
Norton Sound; however, project impacts are not expected to reach
traditional harvest areas.
Ice seals are also hunted within the Norton Sound region. Georgette
et al. (1998) summarizes a subsistence survey of six Norton Sound-
Bering Strait communities (Mainland coastal: Brevig Mission, Golovin,
Shaktoolik, and Stebbins; Offshore: Savoonga and Gambell) between 1996
and 1997 and reports seals taken for subsistence in all months, with
seasonal peaks in spring (May-June) and fall (September-October).
Bearded seals, preferred for their large size and quality of meat, were
harvested by all communities, but Gambell had the highest harvest rate
of any community. Bearded seals are typically harvested in early summer
as they migrate northward. Spotted seals, valued for their skins, are
reported in large numbers during ice-free months (Georgette et al.
1998). Spotted seals occur closer to shore, allowing for easier
harvesting than bearded seals or walrus, which occur further from shore
and for a shorter window as they migrate north
[[Page 27482]]
more quickly (Oceana and Kawerak 2014). Ringed seals, the most abundant
and accessible, were harvested in all months and taken in higher
numbers than other species from the mainland coastal communities.
Ribbon seals are harvested less often than other seals because their
distribution does not overlap with most hunting areas and their taste
is not preferred (Oceana and Kawerak 2014).
Steller sea lions are rarely harvested in Norton Sound. During the
1996-1997 survey, no Steller sea lion harvest was reported, however,
hunters in Gambell, Savoonga, and Brevig Mission reported they do hunt
for them occasionally (Georgette et al. 1998). Additionally, only 20
Steller sea lions were reported taken between 1992 and 1998 (NMFS 2008;
Wolf and Mishler 1999; Wolf and Hutchinson-Scarbrough 1999).
Project activities mostly avoid traditional ice seal harvest
windows (noted above) and are generally not expected to negatively
impact hunting of seals. However, as noted above, some seal hunting
does occur throughout the project period. The project could deter
target species and their prey from the project area, increasing effort
required for a successful hunt in that area. Construction may also
disturb beluga whales, potentially causing them to avoid the project
area and reducing their availability to subsistence hunters as well.
Additionally, once the project is complete, the increased length and
infrastructure at the Port of Nome could impact hunters' ability to
access subsistence areas by increasing the time and fuel needed to exit
the harbor, and increased vessel traffic at the Port following
construction may introduce larger obstacles for subsistence vessels to
maneuver and may affect marine mammals and their movements.
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.
Mitigation for Marine Mammals and Their Habitat
Shutdown 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). Construction supervisors and crews, PSOs, and
relevant USACE staff must avoid direct physical interaction with marine
mammals during construction activity. If a marine mammal comes within
10 meters of such activity, operations must cease and vessels must
reduce speed to the minimum level required to maintain steerage and
safe working conditions, as necessary to avoid direct physical
interaction. Further, USACE must implement activity-specific shutdown
zones as described in Table 10.
Table 10--Required Shutdown Zones
----------------------------------------------------------------------------------------------------------------
Shutdown zone (m)
Pile type Pile driving method -------------------------------
Cetaceans Pinnipeds
----------------------------------------------------------------------------------------------------------------
Temporary template piles (Pipe piles <=24'').. Vibratory....................... 10 10
Impact.......................... 300 150
(Alternate) Temporary template piles (H-piles Vibratory....................... 10 10
14'').
Impact.......................... 300 150
Anchor piles (14'' HP14x89 or similar)........ Vibratory....................... 10 10
Impact.......................... 300 150
Sheet piles (20'' PS31 or similar)............ Vibratory....................... 30 30
Impact.......................... 300 150
Fender piles (Pipe piles 36'')................ Vibratory....................... 70 30
Impact.......................... 500 210
Dredging \a\.................................. ................................ 300 300
----------------------------------------------------------------------------------------------------------------
\a\ As noted previous, take of marine mammals is not anticipated to occur due to dredging. However, USACE will
implement a shutdown zone of 300 m for all marine mammals during dredging.
Protected Species Observers--The placement of PSOs during all
construction activities (described in the Proposed Monitoring and
Reporting section) would ensure that the entire shutdown zone is
visible. USACE would employ three PSOs for vibratory driving of
temporary template pipe piles, sheet piles, and fender pipe piles. For
all other activities, USACE would employ one PSO.
Pre and Post-Activity Monitoring--Monitoring must take place from
30 minutes prior to initiation of pile driving activity (i.e., pre-
start clearance monitoring) through 30 minutes post-completion of pile
driving activity. Pre-start clearance monitoring must be conducted
during periods of visibility sufficient for the lead PSO to determine
that the shutdown zones indicated in Table 10 are clear of marine
mammals.
[[Page 27483]]
Pile driving may commence following 30 minutes of observation when the
determination is made that the shutdown zones are clear of marine
mammals. If a marine mammal is observed entering or within the shutdown
zones, pile driving activity must be delayed or halted. If pile driving
is delayed or halted due to the presence of a marine mammal, the
activity may not commence or resume until either the animal has
voluntarily exited and been visually confirmed beyond the shutdown zone
or 15 minutes have passed without re-detection of the animal. If a
marine mammal for which take by Level B harassment is authorized is
present in the Level B harassment zone, activities would begin and
Level B harassment take would be recorded.
Monitoring for 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.
Soft Start--Soft-start procedures are used 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, soft start requires contractors
to provide an initial set of three strikes at reduced energy, followed
by a 30-second waiting period, then two subsequent reduced-energy
strike sets. A soft start must be implemented at the start of each
day's impact pile driving and at any time following cessation of impact
pile driving for a period of 30 minutes or longer.
Mitigation for Subsistence Uses of Marine Mammals or Plan of
Cooperation
Regulations at 50 CFR 216.104(a)(12) further require IHA applicants
conducting activities in or near a traditional Arctic subsistence
hunting area and/or that may affect the availability of a species or
stock of marine mammals for Arctic subsistence uses to provide a Plan
of Cooperation or information that identifies what measures have been
taken and/or will be taken to minimize adverse effects on the
availability of marine mammals for subsistence purposes. A plan must
include the following:
<bullet> A statement that the applicant has notified and provided
the affected subsistence community with a draft plan of cooperation;
<bullet> A schedule for meeting with the affected subsistence
communities to discuss proposed activities and to resolve potential
conflicts regarding any aspects of either the operation or the plan of
cooperation;
<bullet> A description of what measures the applicant has taken
and/or will take to ensure that proposed activities will not interfere
with subsistence whaling or sealing; and
<bullet> What plans the applicant has to continue to meet with the
affected communities, both prior to and while conducting the activity,
to resolve conflicts and to notify the communities of any changes in
the operation.
USACE provided a draft Plan of Cooperation (POC) to affected
parties in October 2022. It includes a description of the project,
community outreach that has already been conducted, and project
mitigation measures for subsistence uses of marine mammals. USACE will
continue to meet with the potentially affected communities and
subsistence groups to discuss the project, its potential effects on
subsistence, and proposed mitigation measures. Prior to the start of
construction, USACE will provide notice to the communities of upcoming
construction and timing updates using local radio stations, posted
flyers, or other appropriate methods to ensure communities are aware of
the construction activities. During construction, USACE will host a
weekly call with subsistence leaders, construction leads, and the
monitoring team lead(s) to discuss the items listed below, and it will
distribute a one-page flyer via email to subsistence groups and
construction teams.
<bullet> Planned construction activities occurring that day;
<bullet> Anticipated construction activities over the next day/
days;
<bullet> Any reported subsistence activities to be aware of (e.g.,
planned seal hunting and locations);
<bullet> Any other notable or pertinent project of subsistence
information; and
<bullet> Project contact information (phone/email) for real-time
communication.
USACE will monitor this information consistently during the
construction season and maintain communication with subsistence leaders
to employ adaptive measures to mitigate any conflict with subsistence
activities.
The POC is a live document and will be updated throughout the
project review and permitting process.
In addition to the coordination described above to avoid or
mitigate impacts to subsistence harvests of beluga whale and Steller
sea lion, much of the project season avoids traditional ice seal
harvest windows, which would be expected to avoid impacts to hunting of
ice seals during much of the project season. USACE will coordinate with
local communities and subsistence groups throughout construction to
avoid or mitigate impacts to ice seal harvests.
Based on our evaluation of USACE's proposed measures, as well as
other measures considered by NMFS, 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
[[Page 27484]]
cumulative impacts from multiple stressors;
<bullet> How anticipated responses to stressors impact either: (1)
long-term fitness and survival of individual marine mammals; or (2)
populations, species, or stocks;
<bullet> Effects on marine mammal habitat (e.g., marine mammal prey
species, acoustic habitat, or other important physical components of
marine mammal habitat); and,
<bullet> Mitigation and monitoring effectiveness.
Visual Monitoring
Marine mammal monitoring must be conducted in accordance with the
Marine Mammal Monitoring Plan, dated February 2023. Marine mammal
monitoring during pile driving and removal 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 a NMFS-issued incidental take authorization.
PSOs may also substitute Alaska native traditional knowledge for
experience. (NMFS recognizes that PSOs with traditional knowledge may
also have prior experience, and therefore be eligible to serve as the
lead PSO.);
<bullet> Where a team of three or more PSOs is required, a lead
observer or monitoring coordinator must be designated. The lead
observer must have prior experience performing the duties of a PSO
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 must have the following additional qualifications:
<bullet> Ability to conduct field observations and collect data
according to assigned protocols;
<bullet> Experience or training in the field identification of
marine mammals, including the identification of behaviors;
<bullet> Sufficient training, orientation, or experience with the
construction operation to provide for personal safety during
observations;
<bullet> Writing skills sufficient to prepare a report of
observations including but not limited to the number and species of
marine mammals observed; dates and times when in-water construction
activities were conducted; dates, times, and reason for implementation
of mitigation (or why mitigation was not implemented when required);
and marine mammal behavior; and
<bullet> Ability to communicate orally, by radio or in person, with
project personnel to provide real-time information on marine mammals
observed in the area as necessary.
USACE would employ three PSOs for vibratory driving of temporary
template pipe piles, sheet piles, and fender pipe piles. For all other
activities, USACE would employ one PSO. One PSO will be have an
unobstructed view of all water within the shutdown zone and will be
stationed at or near the project activity. Remaining PSOs, when
applicable, will observe as much of the Level B harassment zone as
possible. The second and third PSOs, when applicable, will monitor from
the shoreline approximately 3.5 km to the east and west of the Port of
Nome. While the exact monitoring stations have not yet been determined,
USACE provided potential locations in Figure A-1 (Appendix A) of its
Marine Mammal Monitoring and Mitigation Plan.
Monitoring would be conducted 30 minutes before, during, and 30
minutes after all in water construction activities. In addition, PSOs
would record all incidents of marine mammal occurrence, regardless of
distance from activity, and would document any behavioral reactions in
concert with distance from piles being driven or removed. Pile driving
activities include the time to install or remove a single pile or
series of piles, as long as the time elapsed between uses of the pile
driving equipment is no more than 30 minutes.
Reporting
USACE would submit a draft report to NMFS within 90 calendar days
of the completion of monitoring or 60 calendar days prior to the
requested issuance of any subsequent IHA for construction activity at
the same location, whichever comes first. The marine mammal monitoring
report would include an overall description of work completed, a
narrative regarding marine mammal sightings, and associated PSO data
sheets. Specifically, the report would 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, vibratory, down-the-hole);
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 any other relevant
weather conditions including cloud cover, fog, sun glare, and overall
visibility to the horizon, and estimated observable distance;
<bullet> Upon observation of a marine mammal, the following
information: (1) Name of PSO who sighted the animal(s) and PSO location
and activity at 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.
In the event that personnel involved in the construction activities
discover an injured or dead marine mammal, the
[[Page 27485]]
Holder must report the incident to the Office of Protected Resources
(OPR), NMFS (<a href="/cdn-cgi/l/email-protection#5d0d0f7314090d731032333429322f34333a0f382d322f292e1d33323c3c733a322b"><span class="__cf_email__" data-cfemail="b6e6e498ffe2e698fbd9d8dfc2d9c4dfd8d1e4d3c6d9c4c2c5f6d8d9d7d798d1d9c0">[email protected]</span></a> and <a href="/cdn-cgi/l/email-protection" class="__cf_email__" data-cfemail="e1889591cf8580978892a18f8e8080cf868e97">[email protected]</a>)
and to the 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:
[ssquf] Time, date, and location (latitude/longitude) of the first
discovery (and updated location information if known and applicable);
[ssquf] Species identification (if known) or description of the
animal(s) involved;
[ssquf] Condition of the animal(s) (including carcass condition if
the animal is dead);
[ssquf] Observed behaviors of the animal(s), if alive;
[ssquf] If available, photographs or video footage of the
animal(s); and
[ssquf] General circumstances under which the animal was
discovered.
Monitoring Plan Peer Review
The MMPA requires that monitoring plans be independently peer
reviewed where the proposed activity may affect the availability of a
species or stock for taking for subsistence uses (16 U.S.C.
1371(a)(5)(D)(ii)(III)). Regarding this requirement, NMFS' implementing
regulations state that upon receipt of a complete monitoring plan, and
at its discretion, NMFS will either submit the plan to members of a
peer review panel for review or within 60 days of receipt of the
proposed monitoring plan, schedule a workshop to review the plan (50
CFR 216.108(d)).
NMFS established an independent peer review panel to review USACE's
Monitoring Plan for the Port of Nome Modification Project. NMFS
provided the panel with a copy of USACE's monitoring plan and provided
them with a list of considerations to guide their discussion of the
monitoring plan. The panel met in March 2023 and provided a final
report to NMFS containing recommendations for USACE's monitoring plan
on April 5, 2023. The Peer Review Panel's full report is posted on
NMFS' website at <a href="https://www.fisheries.noaa.gov/national/marine-mammal-protection/incidental-take-authorizations-construction-activities">https://www.fisheries.noaa.gov/national/marine-mammal-protection/incidental-take-authorizations-construction-activities</a>. NMFS
is considering all of the recommendations made by the Peer Review panel
and will incorporate appropriate changes in the monitoring requirements
of the IHA, if issued. Additionally, NMFS will describe how the Peer
Review Panel's findings and recommendations have been addressed in the
Federal Register notice announcing the final IHA, if issued.
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 9, 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 and removal 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, from underwater sounds generated from
pile driving and removal. Potential takes could occur if individuals of
these species are present in zones ensonified above the thresholds for
Level B harassment, identified above, when these activities are
underway.
The takes by Level B harassment would be due to potential
behavioral disturbance. No mortality or serious injury is anticipated
given the nature of the activity, and no Level A harassment is
anticipated due to USACE's construction method and planned mitigation
measures (see Proposed Mitigation section).
Effects on individuals that are taken by Level B harassment, on the
basis of reports in the literature as well as monitoring from other
similar activities, would likely be limited to reactions such as
increased swimming speeds, increased surfacing time, or decreased
foraging (if such activity were occurring; e.g., Thorson and Reyff
2006; HDR, Inc. 2012; Lerma 2014; ABR 2016). Most likely, individuals
would simply move away from the sound source and be temporarily
displaced from the areas of pile driving and removal, although even
this reaction has been observed primarily only in association with
impact pile driving, which USACE does not plan to conduct expect in
scenarios where it is required to successfully advance a pile. If sound
produced by project activities is sufficiently disturbing, animals are
likely to simply avoid the area while the activity is occurring,
particularly as the project is expected to occur over just 85 in-water
pile driving days.
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 some fish to leave the area of
disturbance, thus temporarily impacting marine mammals' foraging
opportunities in a limited portion of the foraging range. We do not
expect pile driving activities to have significant consequences to
marine invertebrate populations. Given the short duration of the
activities and the relatively small area of the habitat that may be
affected, the impacts to marine mammal habitat, including fish and
invertebrates, are not expected to cause significant or long-term
negative consequences.
[[Page 27486]]
The project area overlaps a BIA identified as important for feeding
by Eastern Bering Sea belugas (Brower et al. 2023). The BIA that
overlaps the project area is active May through November, which
overlaps USACE's proposed work period (May to October). The BIA is
considered to be of moderate importance, has moderately certain
boundaries, and moderate data to support the identification of the BIA.
The BIA was identified as having dynamic spatiotemporal variability.
Regardless of the exact boundary of the BIA, the portion of the BIA
that overlaps the project area would be extremely small in comparison
to the full BIA. Further, the majority of the southeastern half of
Norton Sound is separately identified as a ``child'' of the BIA that
overlaps the project area. The child encompasses an especially high-
density area where belugas congregate to feed and is considered to be
of higher importance than the parent BIA. The child BIA does not
overlap the project area, indicating that animals in the Nome area
would have available, high quality feeding habitat during the project
period without necessarily being disturbed by the construction.
Therefore, take of beluga whales using the parent BIA, given both the
scope and nature of the anticipate impacts of pile driving exposure, is
not anticipated to impact reproduction or survivorship of any
individuals.
The project area also overlaps ESA-designated critical habitat for
both ringed seals and bearded seals. As described in the Description of
Marine Mammals in the Area of Specified Activities section above, for
both ringed seals and bearded seals, two of the three essential
features identified for conservation of the species are related to sea
ice. Given that USACE's project is anticipated to occur in the open
water season, impacts from the project on sea ice habitat are not
anticipated. The third essential feature for both ringed and bearded
seals is primary prey sources to support the species. While the project
activities could impact ringed seal and bearded seal foraging
activities in critical habitat that overlaps the project area, the
overlap between these areas is extremely small in comparison to the
full ESA-designated critical habitat for each species, which includes
most of the waters within the U.S. EEZ.
As previously described, a UME has been declared for gray whales.
However, we do not expect the takes proposed for authorization herein
to exacerbate the ongoing UME. No injury, serious injury, or mortality
of gray whales is expected or proposed for authorization, and take by
Level B harassment is limited (14 takes over the duration of the
authorization). As such, the proposed take by Level B harassment of
gray whale would not exacerbate or compound upon the ongoing UME.
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 injury, serious injury, or mortality is anticipated or
authorized;
<bullet> The anticipated incidents of Level B harassment would
consist of, at worst, temporary modifications in behavior that would
not result in fitness impacts to individuals;
<bullet> The area impacted by the specified activity is very small
relative to the overall habitat ranges of all species;
<bullet> While impacts would occur within areas that are important
for feeding for multiple stocks, because of the small footprint of the
activity relative to the area of these important use areas, and the
scope and nature of the anticipated impacts of pile driving exposure,
we do not expect impacts to the reproduction or survival of any
individuals.
Based on the analysis contained herein of the likely effects of the
specified activity on marine mammals and their habitat, and taking into
consideration the implementation of the proposed monitoring and
mitigation measures, NMFS preliminarily finds that the total marine
mammal take from the proposed activity will have a negligible impact on
all affected marine mammal species or stocks.
Small Numbers
As noted previously, only take of small numbers of marine mammals
may be authorized under sections 101(a)(5)(A) and (D) of the MMPA for
specified activities other than military readiness activities. The MMPA
does not define small numbers and so, in practice, where estimated
numbers are available, NMFS compares the number of individuals taken to
the most appropriate estimation of abundance of the relevant species or
stock in our determination of whether an authorization is limited to
small numbers of marine mammals. When the predicted number of
individuals to be taken is fewer than one-third of the species or stock
abundance, the take is considered to be of small numbers. Additionally,
other qualitative factors may be considered in the analysis, such as
the temporal or spatial scale of the activities.
The number of instances of take for each species or stock proposed
to be taken as a result of this project is included in Table 9. Our
analysis shows that less than one-third of the best available
population abundance estimate of each stock could be taken by
harassment. The number of animals proposed to be taken for all stocks
would be considered small relative to the relevant stock's abundances
even if each estimated taking occurred to a new individual, which is an
unlikely scenario.
A lack of an accepted stock abundance value for the Alaska stock of
minke whale did not allow for the calculation of an expected percentage
of the population that would be affected. The most relevant estimate of
partial stock abundance is 1,233 minke whales in coastal waters of the
Alaska Peninsula and Aleutian Islands (Zerbini et al. 2006). Given 12
proposed takes by Level B harassment for the stock, comparison to the
best estimate of stock abundance shows, at most, 1 percent of the stock
would be expected to be impacted.
For the Bering Sea stock of harbor porpoise, the most reliable
abundance estimate is 5,713, a corrected estimate from a 2008 survey.
However, this survey covered only a small portion of the stock's range,
and therefore, is considered to be an underestimate for the entire
stock (Muto et al. 2022). Given the proposed 24 takes by Level B
harassment for the stock, comparison to the abundance estimate, which
is only a portion of the Bering Sea Stock, shows that, at most, less
than one percent of the stock would be expected to be impacted.
For the Alaska stock of bearded seals, a lack of an accepted stock
abundance value did not allow for the calculation of an expected
percentage of the population that would be affected. As noted in the
2021 Alaska SAR (Muto et al. 2022), an abundance estimate is currently
only available for the portion of bearded seals in the Bering Sea (Conn
et al. 2014). The current abundance estimate for the Bering Sea is
301,836 bearded seals. Given the proposed 2,554 takes by Level B
harassment for the stock, comparison to the Bering Sea estimate, which
is only a portion of the Alaska Stock (also includes animals in the
Chukchi and Beaufort Seas), shows that, at most, less than one percent
of the stock would be expected to be impacted.
The Alaska stock of ringed seals also lack an accepted stock
abundance value, and therefore, we were not able to calculate an
expected percentage of the population that may be affected by USACE's
project. As noted in the 2021 Alaska SAR (Muto et al. 2022), the
[[Page 27487]]
abundance estimate available, 171,418 animals, is only a partial
estimate of the Bering Sea portion of the population (Conn et al.
2014). As noted in the SAR, this estimate does not include animals in
the shorefast ice zone, and the authors did not account for
availability bias. Muto et al. (2022) expect that the Bering Sea
portion of the population is actually much higher. Given the proposed
92 takes by Level B harassment for the stock, comparison to the Bering
Sea partial estimate, which is only a portion of the Alaska Stock (also
includes animals in the Chukchi and Beaufort Seas), shows that, at
most, less than one percent of the stock would be expected to be
impacted.
Based on the analysis contained herein of the proposed activity
(including the proposed mitigation and monitoring measures) and the
anticipated take of marine mammals, NMFS preliminarily finds that small
numbers of marine mammals would be taken relative to the population
size of the affected species or stocks.
Unmitigable Adverse Impact Analysis and Determination
In order to issue an IHA, NMFS must find that the specified
activity will not have an ``unmitigable adverse impact'' on the
subsistence uses of the affected marine mammal species or stocks by
Alaskan natives. NMFS has defined ``unmitigable adverse impact'' in 50
CFR 216.103 as an impact resulting from the specified activity: (1)
That is likely to reduce the availability of the species to a level
insufficient for a harvest to meet subsistence needs by: (i) Causing
the marine mammals to abandon or avoid hunting areas; (ii) Directly
displacing subsistence users; or (iii) Placing physical barriers
between the marine mammals and the subsistence hunters; and (2) That
cannot be sufficiently mitigated by other measures to increase the
availability of marine mammals to allow subsistence needs to be met.
Project impacts are generally not expected to reach traditional
beluga harvest areas, and much of the project season avoids traditional
ice seal harvest windows. While some hunting continues throughout the
summer, we do not anticipate that there would be impacts to seals that
would make them unavailable for subsistence hunters. Further, USACE
will coordinate with local communities and subsistence groups
throughout construction and avoid or mitigate impacts to marine mammal
harvests by adaptively managing the project.
Based on the description of the specified activity, the measures
described to minimize adverse effects on the availability of marine
mammals for subsistence purposes, and the proposed mitigation and
monitoring measures, NMFS has preliminarily determined that there will
not be an unmitigable adverse impact on subsistence uses from USACE's
proposed activities.
Endangered Species Act
Section 7(a)(2) of the Endangered Species Act of 1973 (ESA; 16
U.S.C. 1531 et seq.) requires that each Federal agency insure that any
action it authorizes, funds, or carries out is not likely to jeopardize
the continued existence of any endangered or threatened species or
result in the destruction or adverse modification of designated
critical habitat. To ensure ESA compliance for the issuance of IHAs,
NMFS OPR consults internally whenever we propose to authorize take for
endangered or threatened species, in this case with the Alaska Regional
Office.
NMFS is proposing to authorize take of Western DPS Steller sea
lion, ringed seal (Arctic subspecies), and bearded seal (Beringia DPS),
which are listed under the ESA. The Permits and Conservation Division
has requested initiation of section 7 consultation with the Alaska
Regional Office for the issuance of this IHA. NMFS will conclude the
ESA consultation prior to reaching a determination regarding the
proposed issuance of the authorization.
Proposed Authorization
As a result of these preliminary determinations, NMFS proposes to
issue an IHA to USACE for conducting the Port of Nome Modification
Project in Nome, Alaska, during the open water season in 2024, provided
the previously mentioned mitigation, monitoring, and reporting
requirements are incorporated. A draft of the proposed IHA can be found
at: <a href="https://www.fisheries.noaa.gov/national/marine-mammal-protection/incidental-take-authorizations-construction-activities">https://www.fisheries.noaa.gov/national/marine-mammal-protection/incidental-take-authorizations-construction-activities</a>
Request for Public Comments
We request comment on our analyses, the proposed authorization, and
any other aspect of this notice of proposed IHA for the proposed
construction project. We also request comment on the potential renewal
of this proposed IHA as described in the paragraph below. Please
include with your comments any supporting data or literature citations
to help inform decisions on the request for this IHA or a subsequent
renewal IHA.
On a case-by-case basis, NMFS may issue a one-time, 1-year renewal
IHA following notice to the public providing an additional 15 days for
public comments when (1) up to another year of identical or nearly
identical activities as described in the Description of Proposed
Activity section of this notice is planned or (2) the activities as
described in the Description of Proposed Activity section of this
notice would not be completed by the time the IHA expires and a renewal
would allow for completion of the activities beyond that described in
the Dates and Duration section of this notice, provided all of the
following conditions are met:
<bullet> A request for renewal is received no later than 60 days
prior to the needed renewal IHA effective date (recognizing that the
renewal IHA expiration date cannot extend beyond 1 year from expiration
of the initial IHA).
<bullet> The request for renewal must include the following:
(1) An explanation that the activities to be conducted under the
requested renewal IHA are identical to the activities analyzed under
the initial IHA, are a subset of the activities, or include changes so
minor (e.g., reduction in pile size) that the changes do not affect the
previous analyses, mitigation and monitoring requirements, or take
estimates (with the exception of reducing the type or amount of take).
(2) A preliminary monitoring report showing the results of the
required monitoring to date and an explanation showing that the
monitoring results do not indicate impacts of a scale or nature not
previously analyzed or authorized.
Upon review of the request for renewal, the status of the affected
species or stocks, and any other pertinent information, NMFS determines
that there are no more than minor changes in the activities, the
mitigation and monitoring measures will remain the same and
appropriate, and the findings in the initial IHA remain valid.
Dated: April 21, 2023.
Kimberly Damon-Randall,
Director, Office of Protected Resources, National Marine Fisheries
Service.
[FR Doc. 2023-09041 Filed 5-1-23; 8:45 am]
BILLING CODE 3510-22-P
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</html>Indexed from Federal Register on May 2, 2023.
This is legal information, not legal advice. Laws vary by jurisdiction and change frequently. Always verify current law with official sources and consult a licensed attorney in your jurisdiction for advice on your specific situation.