[Federal Register Volume 89, Number 48 (Monday, March 11, 2024)]
[Notices]
[Pages 17423-17439]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2024-05105]
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DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
[RTID 0648-XD533]
Takes of Marine Mammals Incidental to Specified Activities;
Taking Marine Mammals Incidental to Eareckson Air Station Fuel Pier
Repair in Alcan Harbor on Shemya Island, Alaska
AGENCY: National Marine Fisheries Service (NMFS), National Oceanic and
Atmospheric Administration (NOAA), Commerce.
ACTION: Notice; issuance of an incidental harassment authorization.
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SUMMARY: In accordance with the regulations implementing the Marine
Mammal Protection Act (MMPA) as amended, notification is hereby given
that NMFS has issued an incidental harassment authorization (IHA) to
the Pacific Air Forces Regional Support Center (USAF) to incidentally
harass marine mammals during construction activities associated with
the Eareckson Air Station (EAS) Fuel Pier Repair in Alcan Harbor,
Shemya Island, Alaska. There are no changes from the proposed
authorization in this final authorization.
DATES: This authorization is effective from April 1, 2024 through March
31, 2025.
ADDRESSES: Electronic copies of the application and supporting
documents, as well as a list of the references cited in this document
cited in this document, may be obtained online at: https://www.fisheries.noaa.gov/national/marine-mammal-protection/incidental-take-authorizations-construction-activities. In case of problems
accessing these documents, please call the contact listed below.
FOR FURTHER INFORMATION CONTACT: Kate Fleming, Office of Protected
Resources, NMFS, (301) 427-8401.
SUPPLEMENTARY INFORMATION:
Background
The MMPA prohibits the ``take'' of marine mammals, with certain
exceptions. Sections 101(a)(5)(A) and (D) of the MMPA (16 U.S.C. 1361
et seq.) direct the Secretary of Commerce (as delegated to NMFS) to
allow, upon request, the incidental, but not intentional, taking of
small numbers of marine mammals by U.S. citizens who engage in a
specified activity (other than commercial fishing) within a specified
geographical region if certain findings are made and either regulations
are proposed or, if the taking is limited to harassment, a notice of a
proposed IHA is provided to the public for review.
Authorization for incidental takings shall be granted if NMFS finds
that the taking will have a negligible impact on the species or
stock(s) and will not have an unmitigable adverse impact on the
availability of the species or stock(s) for taking for subsistence uses
(where relevant). Further, NMFS must prescribe the permissible methods
of taking and other ``means of effecting the least practicable adverse
impact'' on the affected species or stocks and their habitat, paying
particular attention to rookeries, mating grounds, and areas of similar
significance, and on the availability of the species or stocks for
taking for certain subsistence uses (referred to in shorthand as
``mitigation''); and requirements pertaining to the mitigation,
monitoring and reporting of the takings are set forth. The definitions
of all applicable MMPA
[[Page 17424]]
statutory terms cited above are included in the relevant sections
below.
Summary of Request
On May 15, 2023, NMFS received a request from the USACE on behalf
of USAF for an IHA to take marine mammals incidental to construction
associated with the EAS Fuel Pier Repair in Alcan Harbor on Shemya
Island, Alaska. Following NMFS' review of the application, and
discussions between NMFS and USAF, the application was deemed adequate
and complete on September 19, 2023. The USAF's request is for take of
12 species of marine mammals, by Level B harassment and, for a subset
of these species, Level A harassment. Neither USAF nor NMFS expect
serious injury or mortality to result from this activity and,
therefore, an IHA is appropriate. There are no changes from the
proposed IHA to the final IHA.
The IHA will be effective from April 1, 2024 to March 31, 2025.
Description of the Specified Activity
The USAF plans to conduct long-term repairs on the only existing
fuel pier at EAS on Shemya Island, Alaska. The activities that have the
potential to take marine mammals, by Level A harassment and Level B
harassment, include down-the-hole (DTH) drilling, vibratory and impact
installation of temporary and permanent steel pipe piles, and vibratory
removal of temporary steel pipe piles, and would introduce underwater
sounds that may result in take, by Level A harassment and Level B
harassment, of marine mammals. The marine construction associated with
the planned activities is planned to occur over 160 days over 1 year,
accounting for weather delays and mechanical issues. The IHA is
effective from April 1, 2024 to March 31, 2025.
The fuel pier replacement project would include the installation of
an interlocking steel pipe combi-wall system, which will require the
installation and removal of 60 30-inch (in) temporary steel pipe piles
and the installation of 208 42-in round steel interlocking pipe piles
using vibratory, impact, and/or DTH methods.
A detailed description of the planned construction project is
provided in the Federal Register notice for the proposed IHA (88 FR
74451, October 31, 2023). Since that time, no changes have been made to
the planned activities. Therefore, a detailed description is not
provided here. Please refer to that Federal Register notice for the
description of the specific activity.
Comments and Responses
A notice of NMFS' proposal to issue an IHA to USAF was published in
the Federal Register on October 31, 2023 (88 FR 74451). That notice
described, in detail, USAF's activity, the marine mammal species that
may be affected by the activity, and the anticipated effects on marine
mammals. In that notice, we requested public input on the request for
authorization described therein, our analyses, the proposed
authorization, and any other aspect of the notice of proposed IHA, and
requested that interested persons submit relevant information,
suggestions, and comments. During the 30-day public comment period, the
United States Geological Survey noted that they have ``no comment at
this time.'' NMFS received no other public comments.
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; https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessments) and
more general information about these species (e.g., physical and
behavioral descriptions) may be found on NMFS' website (https://www.fisheries.noaa.gov/find-species).
Table 1 lists all species or stocks for which take is expected and
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 authorized here, PBR and
annual serious injury and mortality from anthropogenic sources are
included here as gross indicators of the status of the species or
stocks and other threats.
Marine mammal abundance estimates presented in this document
represent the total number of individuals that make up a given stock or
the total number estimated within a particular study or survey area.
NMFS' stock abundance estimates for most species represent the total
estimate of individuals within the geographic area, if known, that
comprises that stock. For some species, this geographic area may extend
beyond U.S. waters. All managed stocks in this region are assessed in
NMFS' U.S. Alaska 2022 SARs (Young et al., 2023). All values presented
in table 1 are the most recent available at the time of publication and
are available online at: https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessments.
Table 1--Species Likely Impacted by the Specified Activities
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ESA/MMPA status; Stock abundance (CV,
Common name Scientific name Stock strategic (Y/N) Nmin, most recent PBR Annual M/
\1\ abundance survey) \2\ SI \3\
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Order Artiodactyla--Infraorder Cetacea--Mysticeti (baleen whales)
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Family Balaenopteridae:
Fin Whale....................... Balaenoptera physalus.. Northeast Pacific...... E, D, Y UND (UND, UND, 2013) UND 0.6
\4\.
Humpback Whale.................. Megaptera novaeangliae. Western North Pacific.. E, D, Y 1,084, (0.088, 1,007, 3 2.8
2006).
Mexico--North Pacific.. T, D, Y N/A (N/A, N/A, 2006) UND 0.56
\5\.
Hawai[revaps]i......... -, -, N 11,278 (0.56, 7,265, 127 19.6
2020).
Minke Whale..................... Balaenoptera Alaska................. -, -, - N/A (N/A, N/A, N/A) UND 0
acutorostrata. \6\.
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[[Page 17425]]
Odontoceti (toothed whales, dolphins, and porpoises)
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Family Physeteridae:
Sperm whale..................... Physeter macrocephalus. North Pacific.......... E, D, Y UND (UND, UND, 2015) UND 3.5
\7\.
Family Ziphiidae (beaked whales):
Baird's beaked whale............ Berardius bairdii...... Alaska................. -, -, N N/A (N/A, N/A, N/A)\ N/A 0
8\.
Stejneger's Beaked Whale........ Mesoplodon stejnegeri.. Alaska................. -, -, N N/A (N/A, N/A, N/A)\ N/A 0
8\.
Family Delphinidae:
Killer Whale.................... Orcinus orca........... ENP Alaska Resident -, -, N 1,920 (N/A, 1,920, 19 1.3
Stock. 2019).
ENP Gulf of Alaska, -, -, N 587 (N/A, 587, 2012).. 5.9 0.8
Aleutian Islands, and
Bering Sea.
Family Phocoenidae (porpoises):
Dall's Porpoise................. Phocoenoides dalli..... Alaska................. -, -, N UND (UND, UND, 2015) UND 37
\9\.
Harbor Porpoise................. Phocoena phocoena...... Bering Sea............. -, -, Y UNK (UNK, N/A, 2008) UND 0.4
\10\.
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Order Carnivora--Pinnipedia
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Family Otariidae (eared seals and
sea lions):
Northern Fur Seal............... Callorhinus ursinus.... Eastern Pacific........ -, D, Y 626,618 (0.2, 530,376, 11,403 373
2019).
Steller Sea Lion................ Eumetopias jubatus..... Western, U.S........... E, D, Y 52,932 (N/A, 52,932, 318 254
2019).
Family Phocidae (earless seals):
Harbor Seal..................... Phoca vitulina......... Aleutian Islands....... -, -, N 5,588 (N/A, 5,366, 97 90
2018).
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\1\ 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.
\2\ NMFS marine mammal stock assessment reports online at: https://www.nmfs.noaa.gov/pr/sars. CV is coefficient of variation; Nmin is the minimum
estimate of stock abundance. In some cases, CV is not applicable (explain if this is the case).
\3\ These values, found in NMFS's SARs, represent annual levels of human-caused mortality plus serious injury from all sources combined (e.g.,
commercial fisheries, vessel strike). 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.
\4\ The best available abundance estimate for this stock is not considered representative of the entire stock as surveys were limited to a small portion
of the stock's range. Based upon this estimate and the Nmin, the PBR value is likely negatively biased for the entire stock.
\5\ Abundance estimates are based upon data collected more than 8 years ago and therefore current estimates are considered unknown.
\6\ 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.
\7\ The most recent abundance estimate is likely unreliable as it covered a small area that may not have included females and juveniles, and did not
account for animals missed on the trackline. The calculated PBR is not a reliable index for the stock as it is based upon negatively biased minimum
abundance estimate.
\8\ Reliable abundance estimates for this stock are currently unavailable.
\9\ The best available abundance estimate is likely an underestimate for the entire stock because it is based upon a survey that covered only a small
portion of the stock's range.
\10\ 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.
As indicated above, all 12 species (with 15 managed stocks) in
table 1 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 project area are included in table 3-1 of the
IHA application. While blue whale, gray whale, North Pacific right
whale, Pacific white-sided dolphin, and ribbon seal could occur in the
area, the temporal and/or spatial occurrence of these species is such
that take is not expected to occur, and they are not discussed further
beyond the explanation provided here. These species all have extremely
low abundance and most are observed in areas outside of the project
area.
In addition, northern sea otter may be found the western Aleutians.
However, this species is managed by the U.S. Fish and Wildlife Service
and is not considered further in this document.
A detailed description of the of the species likely to be affected
by the USAF's project, including brief introductions to the species and
relevant stocks as well as available information regarding population
trends and threats, and information regarding local occurrence, were
provided in the Federal Register notice for the proposed IHA (88 FR
74451, October 31, 2023); since that time, we are not aware of any
changes in the status of these species and stocks; therefore, detailed
descriptions are not provided here. Please refer to that Federal
Register notice for these descriptions. Please also refer to NMFS'
website (https://www.fisheries.noaa.gov/find-species) for generalized
species accounts.
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
[[Page 17426]]
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 2.
Table 2--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
The effects of underwater noise from the USAF's construction
activities have the potential to result in behavioral harassment of
marine mammals in the vicinity of the project area. The notice of
proposed IHA (88 FR 74451, October 31, 2023) included a discussion of
the effects of anthropogenic noise on marine mammals and the potential
effects of underwater noise from the USAF's construction on marine
mammals and their habitat. That information and analysis is
incorporated by reference into this final IHA determination and is not
repeated here; please refer to the notice of proposed IHA (88 FR 74451,
October 31, 2023).
Estimated Take
This section provides an estimate of the number of incidental takes
authorized 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 primarily be by Level B harassment, as use
of the acoustic sources (i.e., impact and vibratory pile driving and
removal and DTH) has the potential to result in disruption of
behavioral patterns for individual marine mammals. There is also some
potential for auditory injury (Level A harassment) to result, primarily
for mysticetes and/or high frequency species and/or phocids because
predicted auditory injury zones are larger than for mid-frequency
species and/or otariids. Auditory injury is unlikely to occur for other
groups. The required mitigation and monitoring measures are expected to
minimize the severity of the taking to the extent practicable.
As described previously, no serious injury or mortality is
anticipated or authorized for this activity. Below we describe how the
authorized 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 how take is estimated.
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; Southall et al., 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
[[Page 17427]]
generalized acoustic threshold based on received level to estimate the
onset of behavioral harassment. NMFS generally predicts that marine
mammals are likely to be behaviorally harassed in a manner considered
to be Level B harassment when exposed to underwater anthropogenic noise
above root-mean-squared pressure received levels (RMS SPL) of 120 dB
(referenced to 1 micropascal (re 1 [mu]Pa)) for continuous (e.g.,
vibratory pile driving, drilling) and above RMS SPL 160 dB re 1 [mu]Pa
for non-explosive impulsive (e.g., seismic airguns) or intermittent
(e.g., scientific sonar) sources. Generally speaking, Level B
harassment take estimates based on these behavioral harassment
thresholds are expected to include any likely takes by TTS as, in most
cases, the likelihood of TTS occurs at distances from the source less
than those at which behavioral harassment is likely. TTS of a
sufficient degree can manifest as behavioral harassment, as reduced
hearing sensitivity and the potential reduced opportunities to detect
important signals (conspecific communication, predators, prey) may
result in changes in behavior patterns that would not otherwise occur.
USAF's planned activity includes the use of continuous (vibratory pile
driving and removal and DTH) and impulsive (impact pile driving and
DTH) sources, and therefore the RMS SPL thresholds of 120 and 160 dB re
1 [mu]Pa is/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). USAF's
planned activity includes the use of impulsive (impact pile driving and
DTH) and non-impulsive (vibratory pile driving and removal and DTH)
sources.
These thresholds are provided in the table below. The references,
analysis, and methodology used in the development of the thresholds are
described in NMFS' 2018 Technical Guidance, which may be accessed at:
https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-acoustic-technical-guidance.
Table 3--Thresholds Identifying the Onset of Permanent Threshold Shift
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PTS onset acoustic thresholds * (received level)
Hearing group ------------------------------------------------------------------------
Impulsive Non-impulsive
----------------------------------------------------------------------------------------------------------------
Low-Frequency (LF) Cetaceans........... Cell 1: Lpk,flat: 219 dB; Cell 2: LE,LF,24h: 199 dB.
LE,LF,24h: 183 dB.
Mid-Frequency (MF) Cetaceans........... Cell 3: Lpk,flat: 230 dB; Cell 4: LE,MF,24h: 198 dB.
LE,MF,24h: 185 dB.
High-Frequency (HF) Cetaceans.......... Cell 5: Lpk,flat: 202 dB; Cell 6: LE,HF,24h: 173 dB.
LE,HF,24h: 155 dB.
Phocid Pinnipeds (PW) Underwater)...... Cell 7: Lpk,flat: 218 dB; Cell 8: LE,PW,24h: 201 dB.
LE,PW,24h: 185 dB.
Otariid Pinnipeds (OW) (Underwater).... Cell 9: Lpk,flat: 232 dB; Cell 10: LE,OW,24h: 219 dB.
LE,OW,24h: 203 dB.
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* 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 [mu]Pa, and cumulative sound exposure level (LE) has
a reference value of 1[mu]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.
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 planned project.
Marine mammals are expected to be affected via sound generated by the
primary components of the project (i.e., pile driving and removal and
DTH). The maximum (underwater) area ensonified above the thresholds for
behavioral harassment referenced above is 1286 kilometers\2\ (km\2\)
(496 miles\2\ (mi\2\)), and the calculated distance to the farthest
behavioral harassment isopleth is approximately 39,811 meters (m)
(24,737.4 mi).
The project includes vibratory pile installation and removal,
impact pile driving, and DTH. Source levels for these activities are
based on reviews of measurements of the same or similar types and
dimensions of piles available in the literature. Source levels for each
pile size and activity are presented in table 4. Source levels for
vibratory installation and removal of piles of the same diameter are
assumed to be the same.
NMFS recommends treating DTH systems as both impulsive and
continuous, non-impulsive sound source types simultaneously. Thus,
impulsive thresholds are used to evaluate Level A harassment, and
continuous thresholds are used to evaluate Level B harassment. With
regards to DTH mono-hammers, NMFS recommends proxy levels for Level A
harassment based on available data regarding DTH systems of similar
sized piles and holes (Denes et al., 2019; Reyff and Heyvaert, 2019;
Reyff, 2020; Heyvaert and Reyff, 2021) (table 4 includes sound pressure
and sound exposure levels for each pile type).
[[Page 17428]]
Table 4--Estimates of Mean Underwater Sound Levels Generated During Vibratory and Impact Pile Installation, DTH,
and Vibratory Pile Removal
----------------------------------------------------------------------------------------------------------------
SSL at 10 m dB
Continuous sound sources rms Literature source
----------------------------------------------------------------------------------------------------------------
Vibratory Hammer
----------------------------------------------------------------------------------------------------------------
42-in steel piles............................. 168.2 Port of Anchorage Test Pile Program (table 16
in Austin et al., 2016).
30-in steel piles............................. 166 * NMFS Analysis (C. Hotchkin, April 24, 2023).
----------------------------------------------------------------------------------------------------------------
DTH
----------------------------------------------------------------------------------------------------------------
42-in steel piles............................. 174 Reyff & Heyvaert, 2019; Reyff, 2020.
30-in steel piles............................. 174 Reyff & Heyvaert, 2019; Reyff, 2020.
----------------------------------------------------------------------------------------------------------------
----------------------------------------------------------------------------------------------------------------
Impulsive sound sources dB rms dB SEL dB peak Literature source
----------------------------------------------------------------------------------------------------------------
Impact Hammer
----------------------------------------------------------------------------------------------------------------
42-in steel piles......................... 192 179 213 Caltrans, 2020.
30-in steel piles......................... 191 177 212 Caltrans, 2020.
----------------------------------------------------------------------------------------------------------------
DTH
----------------------------------------------------------------------------------------------------------------
42-in steel piles......................... N/A 164 194 Reyff & Heyvaert, 2019;
Reyff, 2020; Denes et al.,
2019.
30-in steel piles......................... N/A 164 194 Reyff & Heyvaert, 2019;
Reyff, 2020; Denes et al.,
2019.
----------------------------------------------------------------------------------------------------------------
Note: dB peak = peak sound level; DTH = down-the-hole drilling; rms = root mean square; SEL = sound exposure
level.
* NMFS generated this source level by completing a completed a comprehensive review of source levels relevant to
southeast Alaska; NMFS compiled all available data from Puget Sound and southeast Alaska and adjusted the data
to standardize distance from the measured pile to 10 m. NMFS then calculated average source levels for each
project and for each pile type. NMFS weighted impact pile driving project averages by the number of strikes
per pile following the methodology in Navy (2015).
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 Shemya Island 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 5--User Spreadsheet Inputs
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Vibratory Impact DTH
-----------------------------------------------------------------------------------------------------------------------------------------------------------------
30-in steel piles 42-in steel piles 30-in steel piles 42-in steel piles 30-in steel piles 42-in steel piles
-----------------------------------------------------------------------------------------------------------------------------------------------------------------
Installation or removal Installation Installation Installation Installation Installation
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Spreadsheet Tab Used.......... A.1) Vibratory Pile A.1) Vibratory Pile E.1) Impact Pile Driving. E.1) Impact Pile Driving. E.2) DTH Pile Driving.... E.2) DTH Pile Driving.
Driving. Driving.
Source Level (SPL)............ 166 RMS.................. 168.2 RMS................ 177 SEL.................. 179 SEL.................. 174 RMS, 164 SEL......... 174 RMS, 164 SEL.
Transmission Loss Coefficient. 15....................... 15....................... 15....................... 15....................... 15....................... 15
Weighting Factor Adjustment 2.5...................... 2.5...................... 2........................ 2........................ 2........................ 2
(kHz).
[[Page 17429]]
Activity Duration per day 60....................... 120...................... 120...................... 180...................... 150...................... 180
(minutes).
Strike Rate per second........ ......................... ......................... ......................... ......................... 10....................... 10
Number of strikes per pile.... ......................... ......................... 900...................... 1,800.................... ......................... .........................
Number of piles per day....... 4........................ 4........................ 4........................ 4........................ 3........................ 3
Distance of sound pressure 10....................... 10....................... 10....................... 10....................... 10....................... 10
level measurement.
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Table 6--Level A Harassment and Level B Harassment Isopleths From Vibratory and Impact Pile Driving and DTH
----------------------------------------------------------------------------------------------------------------
Level A harassment isopleths (m) Level B
----------------------------------------------------------------- harassment
Pile type isopleth
LF MF HF PW OW (m)
----------------------------------------------------------------------------------------------------------------
Vibratory
----------------------------------------------------------------------------------------------------------------
42-in steel pipe piles............ 32.7 2.9 48.4 19.9 1.4 16,343
30-in Steel pipe piles............ 14.7 1.3 21.8 8.9 0.6 11,659
----------------------------------------------------------------------------------------------------------------
DTH
----------------------------------------------------------------------------------------------------------------
42-in Steel pipe piles............ 2,549.4 90.7 3,036.7 1,364.3 99.3 39,811
30-in Steel pipe piles............ 2,257.6 80.3 2,689.2 1,208.2 88 39,811
----------------------------------------------------------------------------------------------------------------
Impact
----------------------------------------------------------------------------------------------------------------
42-in steel pipe piles............ 2,015.1 71.7 2,400.3 1,078.4 78.5 1,359
30-in Steel pipe piles............ 933.8 33.2 1,112.3 499.7 36.4 1,166
----------------------------------------------------------------------------------------------------------------
Marine Mammal Occurrence and Take Estimation
In this section we provide information about the occurrence of
marine mammals, including density or other relevant information which
will inform the take calculations. We describe how the information
provided is synthesized to produce a quantitative take estimate.
As described above, for some species (humpback whale, killer whale,
Steller sea lion and harbor seal) observations within the project area
from the prior monitoring were available to directly inform the take
estimates, while for other species (fin whale, minke whale, sperm
whale, Baird's beaked whale, Stejneger's beaked whale, Dall's porpoise,
harbor porpoise and northern fur seal) they were not. Prior surveys
include Protected Species Observer (PSO) monitoring completed at the
project site on 60 days between June and August 2021 during the
emergency fuel pier repair, island-wide faunal surveys completed by the
USACE Engineer Research Development Center (ERDC) across 33 days
between 2016 and 2019 (primarily in the spring and fall), and island-
wide marine mammal surveys completed by the USACE Civil Works
Environmental Resource Section on 26 days between May and October 2021.
From all three surveys, data that were collected within the project
area are primarily the basis for the take estimates because those data
best represents what might be encountered there. Average group sizes
used to inform Level B take estimates (which also underlie the
estimates for Level A harassment) for all species with prior
observations in the project area are primarily based on those data.
Alternate methods utilizing average group sizes informed primarily by
Alaska's Wildlife Notebook Series are used for species without prior
observations.
Also of note, while the results are not significantly different, in
some cases we recommended modified methods for estimating take from
those presented by the applicant and have described them below. A
summary of authorized take, including as a percentage of population for
each of the species, is shown in table 7.
Fin Whale
No fin whale were reported during monitoring conducted for the EAS
fuel pier emergency repair completed in 2021, nor during other surveys
completed from Shemya Island (see application). Accordingly, average
group size, estimated group size based on information shared in the
Alaska Wildlife Notebook Series (Clark, 2008a), is used as the basis
for the take estimates.
USAF requested 17 takes of fin whales by Level B harassment, using
a calculation based on 0.002 groups of eight fin whales per hour of
construction activity. NMFS concurs with USAF's predicted group size of
fin whale (eight individuals), but since there are no observations of
this species from Shemya Island, NMFS finds it more appropriate to
estimate take by Level B harassment using a less granular occurrence
estimate (monthly) rather than USAF's hourly occurrence
[[Page 17430]]
estimate. Specifically, one group of eight fin whales is predicted
every 2 construction months, based on the applicant's prediction that
this species would be rare in the project area. The duration of the
construction is 160 days (2.65 * the basic 60-day period) and 8 * 2.65
= 21 takes by Level B harassment).
Although the shutdown zone is larger than the Level A harassment
zone for low frequency cetaceans, USAF indicates that at >=2,000 m, it
becomes more challenging to reliably detect low frequency cetaceans in
some environmental conditions, and therefore it is possible that a fin
whale could enter the Level A harassment zone during DTH activities and
stay long enough to incur PTS before USAF detects the animal and shuts
down. As such, USAF requested and NMFS authorized a small amount of
take by Level A harassment of fin whales. NMFS calculated takes by
Level A harassment by first determining the proportion of the area of
largest Level A harassment zone (42-in DTH, 2,549 m) that occurs beyond
the readily observable 2,000 m from the pile driving location (i.e.,
7.5 km\2\-5 km\2\/7.5 km\2\ = 0.33). This ratio was multiplied by the
estimated fin whale exposures, which is generally one group of eight
fin whale that would occur every 2 construction months (or 60 days,
adjusted by 1.2 to account for the 70 days that DTH activities are
planned). Multiplying these factors (8 * 1.2 * 0.33) results in three
takes by Level A harassment.
Any individuals exposed to the higher levels associated with the
potential for PTS closer to the source might also be behaviorally
disturbed, however, for the purposes of quantifying take we do not
count those exposures of one individual as both a Level A harassment
take and a Level B harassment take, and therefore takes by Level B
harassment calculated as described above are further modified to deduct
the authorized amount of take by Level A harassment (i.e., 21-3 = 18).
Therefore, NMFS proposes to authorize 3 takes by Level A harassment
and 18 takes by Level B harassment for fin whales, for a total of 21
takes.
Humpback Whale
Across 119 days of marine mammal surveys completed from Shemya
Island between 2016 and 2021, seven humpback whales were observed in
the project area. The average group size for humpback whales detected
in the project area was two humpback whales per group detected.
For estimating take by Level B harassment where monitoring data
confirmed the presence of the marine mammal species, NMFS concurred
with USAF's approach. USAF requested take by Level B harassment by
predicting that 0.07 groups of humpback whales would be sighted every
hour, which was based on the applicant predicting this species would
commonly occur within the project area. This was then multiplied by the
average group size for humpback whales (two individuals), to achieve an
hourly humpback rate. Finally, these numbers are multiplied by the
hours of construction activity (0.07 * 2 * 1,101 = 154 takes by Level B
harassment).
Although the shutdown zone is larger than the Level A harassment
zone for low frequency cetaceans, USAF indicates that at >=2,000 m, it
becomes more challenging to reliably detect low frequency cetaceans in
some environmental conditions, and therefore it is possible that
humpback whales could enter the Level A harassment zone during DTH
activities and stay long enough to incur PTS before USAF detects the
animal and shuts down. As such, USAF requested and NMFS authorized a
small amount of take by Level A harassment of humpback whales. NMFS
calculated takes by Level A harassment by determining the proportion of
the area of largest Level A harassment zone (42-in DTH, 2,549 m) that
occurs beyond 2,000 m from the pile driving location (i.e., 7.5 km\2\-5
km\2\/7.5 km\2\ = 0.33) and multiplying this ratio by the estimated
humpback whale exposures (0.07 groups of 2 humpback whale) that would
occur every construction hour that DTH activities are planned (624
hours) (0.07 * 2 * 624 * 0.33 = 29 takes by Level A harassment).
For the reasons described above, takes by Level B harassment were
modified to deduct the authorized amount of take by Level A harassment
(i.e., 154-29 = 125).
Therefore, NMFS proposes to authorize 29 takes by Level A
harassment and 125 takes by Level B harassment for humpback whales, for
a total of 154 takes.
Minke Whale
No minke whales were reported during monitoring conducted for the
EAS fuel pier emergency repair completed in 2021, nor during other
surveys completed from Shemya Island (e.g., see application).
Accordingly, average group size, estimated based on group size
information shared in the Alaska Wildlife Notebook Series (Clark,
2008a), is used as the basis for the take estimates (Guerrero, 2008b).
USAF requested seven takes of minke whales by Level B harassment,
using a calculation of 0.002 groups of three minke whales per hour of
construction activity. NMFS concurs with USAF's predicted group size of
minke whale (three individuals), but since there are no observations of
this species from Shemya Island, NMFS finds it more appropriate to
estimate take by Level B harassment using a less granular occurrence
estimate (monthly) rather than USAF's hourly occurrence estimate.
Specifically, one group of three minke whales is predicted every 2
construction months, based on the applicant's prediction that this
species would be rare in the project area. The duration of construction
is 160 days (2.65 * the basic 60-day period, which corresponds to 2
months) and 3 * 2.65 = 8 takes by Level B harassment.
Although the shutdown zone is larger than the Level A harassment
zone for low frequency cetaceans, USAF indicates that at >=2,000 m, it
becomes more challenging to reliably detect low frequency cetaceans in
some environmental conditions, and therefore it is possible that a
minke whale could enter the Level A harassment zone during DTH
activities and stay long enough to incur PTS before USAF detects the
animal and shuts down. As such, USAF requested and NMFS authorized a
small amount of take by Level A harassment of minke whales. NMFS
calculated takes by Level A harassment by determining the proportion of
the area of largest Level A harassment zone (42-in DTH, 2,549 m) that
occurs beyond the readily observable 2,000 m from the pile driving
location (i.e., 7.5 km\2\-5 km\2\/7.5 km\2\ = 0.33).This ratio was
multiplied by the estimated minke whale exposures, which is generally
one group of three minke whales every 2 construction months (or 60
days), adjusted by 1.2 to account for the 70 days that DTH activities
are planned. Multiplying these factors (1.2 * 0.33) results in one take
by Level A harassment. Since the predicted average group size of minke
whale is three, NMFS proposes to authorize three takes by Level A
harassment of minke whale.
For reasons described above, takes by Level B harassment were
modified to deduct the authorized amount of take by Level A harassment
(i.e., 8-3 = 5).
Therefore, NMFS proposes to authorize three takes by Level A
harassment and five takes by Level B harassment for minke whales, for a
total of eight takes.
Sperm Whale
Across 119 monitoring days between 2016 and 2021, four sperm whales
were observed on a single day from Shemya
[[Page 17431]]
Island, though outside of the project area (see application).
USAF requested 27 takes of sperm whale by Level B harassment, using
a calculation based on of 0.006 groups of four sperm whales per hour of
construction activity. NMFS concurs with USAF's predicted group size of
sperm whale (four individuals, which corresponds to the number of sperm
whales detected on a single day during Shemya Island marine mammal
surveys), but since there are few observations of this species from
Shemya Island, NMFS finds it more appropriate to estimate take by Level
B harassment using a less granular occurrence estimate (monthly) rather
than USAF's hourly occurrence estimate. Specifically, two groups of
four sperm whales is predicted every 1 construction month based on
sperm whales being one of the most frequently sighted marine mammals in
the high latitude regions of the North Pacific, including the Bering
Sea and the Aleutian Islands. The duration of the construction is 5
months and 2 * 4 * 5 = 40 takes by Level B harassment.
Due to the small Level A harassment zones (table 8), which do not
reach deep water where sperm whales are expected to be encountered,
coupled with the implementation of shutdown zones, which will be larger
than Level A harassment zones for mid-frequency cetaceans (described in
the Mitigation section), NMFS concurs with USAF's assessment that take
by Level A harassment is not anticipated for sperm whale. Therefore,
NMFS authorized all 40 estimated exposures as takes by Level B
harassment. Takes by Level A harassment for sperm whales are not
requested nor are they authorized.
Baird's Beaked Whale
Baird's beaked whales are usually found in tight social groups
(schools or pods) averaging between 5 and 20 individuals, but they have
occasionally been observed in larger groups of up to 50 animals. Across
119 days of marine mammal surveys completed from Shemya Island between
2016 and 2021, no observations of Baird's beaked whale were recorded
(see application). Accordingly, average group size, estimated based on
group size information shared in the Alaska Wildlife Notebook Series
(Guerrero, 2008a), is used as the basis for take estimates.
USAF requested 11 takes by Level B harassment, using a calculation
based on 0.001 groups of ten Baird's beaked whales per hour of
construction activity. NMFS concurs with USAF's predicted group size of
Baird's beaked whale (10 individuals), but since there are no
observations of this species from Shemya Island, NMFS finds it more
appropriate to estimate take by Level B harassment using a less
granular occurrence estimate (monthly) rather than USAF's hourly
occurrence estimate. Specifically, 1 group of 10 Baird's beaked whales
is predicted across the project, which is based on this species being
shy and preferring deep waters and as such the applicant predicted they
would be very rare in the project area. Therefore, NMFS proposes to
authorize 10 takes of Baird's beaked whale by Level B harassment.
Due to the small Level A harassment zones (table 8), which do not
reach deep water where Baird's beaked whales are expected to be
encountered, coupled with the implementation of shutdown zones, which
will be larger than Level A harassment zones for mid-frequency
cetaceans (described in the Mitigation section), NMFS concurs with
USAF's assessment that take by Level A harassment is not anticipated
for Baird's beaked whale. Therefore, NMFS authorized all 10 estimated
exposures as takes by Level B harassment. Takes by Level A harassment
for Baird's beaked whales are not requested nor are they authorized.
Stejneger's Beaked Whale
Across 119 days of marine mammal surveys completed from Shemya
Island between 2016 and 2021, no observations of Stejneger's beaked
whale were recorded (see application). Accordingly, average group size,
estimated based on group size information shared in the Alaska Wildlife
Notebook Series (Guerrero, 2008a), is used as the basis for take
estimates.
USAF requested nine takes of Stejneger's beaked whale by Level B
harassment, using a calculation based on of 0.001 groups of eight
Stejneger's beaked whales per hour of construction activity. NMFS
concurs with USAF's predicted group size of Stejneger's beaked whale
(eight individuals), but since there are no observations of this
species from Shemya Island, NMFS finds it more appropriate to estimate
take by Level B harassment using a less granular occurrence estimate
(monthly) rather than USAF's hourly occurrence estimate. Specifically,
one group of eight Stejneger's beaked whales is predicted across the
entirety of the project, based on this species being shy and preferring
deep waters and as such the applicant predicted they would only be very
rarely encountered in the project area. Therefore, NMFS proposes to
authorize eight Stejneger's beaked whale by level B harassment.
Due to the small Level A harassment zones (table 8), which do not
reach deep water where Stejneger's beaked whales are expected to be
encountered, coupled with the implementation of shutdown zones, which
will be larger than Level A harassment zones for mid-frequency
cetaceans (described in the Mitigation section), NMFS concurs with
USAF's assessment that take by Level A harassment is not anticipated
for Stejneger's beaked whale. Therefore, NMFS authorized all eight
estimated exposures as takes by Level B harassment. Takes by Level A
harassment for Stejneger's beaked whales are not requested nor are they
authorized.
Killer Whale
Across 119 days of marine mammal surveys completed from Shemya
Island between 2016 and 2021, 69 killer whales were observed in the
project area. The average group size for killer whales detected in the
project area was eight killer whales per group detected.
For estimating take by Level B harassment where monitoring data
confirmed the presence of the marine mammal species, NMFS concurred
with USAF's approach. USAF requested take by Level B harassment by
predicting that 0.02 groups of killer whales would be sighted every
hour, which was based on the applicant's prediction that this species
would commonly be encountered in the project area. This was then
multiplied by the average group size for humpback whales (eight
individuals), to achieve an hourly killer whale rate. Finally, these
numbers are multiplied by the hours of construction activity (0.02 * 8
* 1,101 = 176 takes by Level B harassment).
Due to the small Level A harassment zones (table 8), coupled with
the implementation of shutdown zones, which will be larger than Level A
harassment zones for mid-frequency cetaceans (described in the
Mitigation section), NMFS concurs with USAF's assessment that take by
Level A harassment is not anticipated for killer whale. Therefore, NMFS
authorized all 176 estimated exposures as takes by Level B harassment.
Takes by Level A harassment for killer whale are not requested nor are
they authorized.
Dall's Porpoise
No Dall's porpoise were reported during monitoring conducted for
the EAS fuel pier emergency repair completed in 2021, nor during other
surveys completed from Shemya Island (see application). Dall's porpoise
generally travel in groups of 10 to 20 individuals but can occur in
groups
[[Page 17432]]
with over hundreds of individuals (Wells, 2008). Accordingly, average
group size, estimated based group size information shared in the Alaska
Wildlife Notebook Series (Wells 2008), is used as the basis for the
take estimates, is used as the basis for take estimates.
USAF requested 33 takes of Dall's porpoise by Level B harassment,
using a calculation based on of 0.002 groups of 15 Dall's porpoise per
hour of construction activity. NMFS concurs with USAF's predicted group
size of Dall's porpoise (15 individuals), but since there are no
observations of this species from Shemya Island, NMFS finds it more
appropriate to estimate take by Level B harassment using a less
granular occurrence estimate (monthly) rather than USAF's hourly
occurrence estimate. Specifically, 1 group of 15 Dall's porpoise is
predicted every 2 construction months, based on the applicant's
prediction that this species would be rarely encountered in the project
area. The duration of the construction is 160 days (2.65 * the basic
60-day period that corresponds to 2 construction months) and 15 * 2.65
= 40 takes by Level B harassment.
For most activities, NMFS calculated takes by Level A harassment by
determining the ratio of the largest Level A harassment area for 42-in
DTH activities (i.e., 10.2 km\2\ for a Level A harassment distance of
3,037 m) minus the area of the shutdown zone for Dall's porpoise (i.e.,
0.5 km\2\ for a shutdown zone distance of 500 m) to the area of the
Level B harassment isopleth (1,285.9 km\2\) for a Level B harassment
distance of 39,811 m (i.e., (10.2 km\2\-0.5 km\2\)/1,285.9 km\2\ =
0.008). We then multiplied this ratio by the number of estimated Dall's
porpoise exposures calculated as described above for Level B harassment
to determine take by Level A harassment (i.e., 0.008 * 40 exposures =
0.32 takes by Level A harassment).
For Level A harassment during impact pile driving of 42-in piles,
for which the Level A harassment zone is larger than the Level B
harassment zone, NMFS estimates take based on 1 group of 15 Dall's
porpoise every 2 months, or 60 days, in consideration of the 52 days
(0.87 of 60) of impact driving of 42-in piles (15 Dall's porpoise *
0.87 months = 13.05) for a total of 13.37 takes by Level A harassment
(0.32 + 13.05 = 13).
For reasons described above, takes by Level B harassment were
modified to deduct the authorized amount of take by Level A harassment
(i.e., 40-13 = 27).
Therefore, NMFS proposes to authorize 13 takes by Level A
harassment and 27 takes by Level B harassment for Dall's porpoise, for
a total of 40 takes.
Harbor Porpoise
Across 119 monitoring days between 2016 and 2021, one group of two
to three harbor porpoise were observed from Shemya Island (see
application), though outside of the project area. Average group size,
estimated based on the Alaska Wildlife Notebook Series (Schmale, 2008),
is used as the basis for take estimates.
USAF requested 11 takes of harbor porpoise by Level B harassment,
using a calculation based on of 0.01 groups of 1 harbor porpoise per
hour of construction activity. NMFS concurs with USAF's predicted group
size of harbor porpoise (one individual), but since there are few
observations of this species from Shemya Island, NMFS finds it more
appropriate to estimate take by Level B harassment using a less
granular occurrence estimate (monthly) rather than USAF's hourly
occurrence estimate. Specifically, three groups of one harbor porpoise
is predicted every 1 construction month. The duration of construction
is 5 months and 3 * 5 = 15 takes by Level B harassment.
For most activities, NMFS calculated takes by Level A harassment by
determining the ratio of the largest Level A harassment area for 42-in
DTH activities (i.e., 10.2 km\2\ for a Level A harassment distance of
3,037 m) minus the area of the shutdown zone for harbor porpoise (i.e.,
0.5 km\2\ for a shutdown zone distance of 500 m) to the area of the
Level B harassment isopleth (1,285.9 km\2\) for a Level B harassment
distance of 39,811 m (i.e., (10.2 km\2\-0.5 km\2\)/1,285.9 km\2\ =
0.008). We then multiplied this ratio by the number of estimated harbor
porpoise exposures calculated as described above for Level B harassment
to determine take by Level A harassment (i.e., 0.008 * 15 exposures =
0.12 takes by Level A harassment).
For Level A harassment during impact pile driving of 42-in piles,
for which the Level A harassment zone is larger than the Level B
harassment zone, NMFS estimates take based on three groups of one
harbor porpoise could be taken by Level A harassment every 1 month, or
30 days in consideration of the 52 days (1.7 * 30) of impact pile
driving of 42-in piles (3 groups of 1 harbor porpoise * 1.7 = 5.1) for
a total of five takes by Level A harassment (0.12 + 5.1 = 5).
For reasons described above, takes by Level B harassment were
modified to deduct the authorized amount of take by Level A harassment
(i.e., 15-5 = 10).
Therefore, NMFS proposes to authorize 5 takes by Level A harassment
and 10 takes by Level B harassment for harbor porpoise, for a total of
15 takes.
Northern Fur Seal
USAF requested 33 takes of northern fur seal by Level B harassment
using a calculation based on 0.003 groups of eight northern fur seals
per hour of construction activity. NMFS disagrees with USAF's predicted
group size of northern fur seal, as these animals are typically
solitary when at sea. Additionally, because there are no records of
northern fur seal in the area, NMFS finds it more appropriate to
estimate take by Level B harassment according to a less granular
occurrence estimate (monthly) rather than USAF's hourly occurrence
estimate. Specifically, one group of one northern fur seal every 1
construction month is predicted and 1 * 5 = 5 takes by Level B
harassment.
Due to the small Level A harassment zones (table 8), coupled with
the implementation of shutdown zones, which will be larger than Level A
harassment zones for otariids (described in the Mitigation section),
NMFS concurs with USAF's assessment that take by Level A harassment is
not anticipated for northern fur seal. Therefore, NMFS authorized all
five estimated exposures as takes by Level B harassment. Takes by Level
A harassment for northern fur seals are not requested nor are they
authorized.
Steller Sea Lion
Steller sea lions are frequently observed around Shemya Island
outside of the ensonified area, but only occasionally observed in Alcan
Harbor and Shemya Pass (see application). Across 119 monitoring days
between 2016 and 2021, 16 Steller sea lions were observed within the
project area. The average group size for Steller sea lion detected in
the project area as well as around Shemya Island was one Steller sea
lion per detection.
For estimating take by Level B harassment where monitoring data
confirmed the presence of the marine mammal species, NMFS concurred
with USAF's planned approach. USAF requested take by Level B harassment
by predicting that 0.09 groups of Steller sea lion would be sighted
every hour, which was based on the applicant's prediction that this
species would be more commonly encountered in the project area. This
was then multiplied by the average group size for Steller sea lion (1
individual), to achieve an hourly steller sea lion rate. Finally, these
numbers are multiplied by the hours of construction activity (0.09 * 1
* 1,101 = 99 takes by Level B harassment).
[[Page 17433]]
Due to the small Level A harassment zones (table 8), coupled with
the implementation of shutdown zones, which will be larger than Level A
harassment zones for otariids (described in the Mitigation section),
NMFS concurs with USAF's assessment that take by Level A harassment is
not anticipated for Steller sea lion. Therefore, NMFS authorized all 99
estimated exposures as takes by Level B harassment. Takes by Level A
harassment for Steller sea lion are not requested nor are they
authorized.
Harbor Seal
Across 119 monitoring days between 2016 and 2021, 54 harbor seals
were observed within the project area. The average group size for
harbor seals detected in the project area was one harbor seals per
group.
For estimating take by Level B harassment where monitoring data
confirmed the presence of the marine mammal species, NMFS concurred
with USAF's planned approach. USAF requested take by Level B harassment
by predicting that 0.14 groups of harbor seals would be sighted every
hour, which was based on the fact that this species is expected to more
commonly occur within the project area. This was then multiplied by the
average group size for harbor seal (1 individual), to achieve an hourly
harbor seal rate. Finally, these numbers are multiplied by the hours of
construction activity (0.14 * 1 * 1,101 = 154 takes by Level B
harassment).
NMFS initially calculated takes by Level A harassment by
determining the ratio of the largest Level A harassment area for 42-in
DTH activities (i.e., 2.6 km\2\ for a Level A harassment distance of
1364 m) minus the area of the shutdown zone for harbor seal (i.e., 0.37
km\2\ for a shutdown zone distance of 400 m) to the area of the Level B
harassment isopleth (1,285.9 km\2\) for a Level B harassment distance
of 39,811 m (i.e., (2.6 km\2\-0.37 km\2\)/1,285.9 km\2\ = 0.002). We
then multiplied this ratio by the number of estimated harbor seal
exposures calculated as described above for Level B harassment to
determine take by Level A harassment (i.e., 0.002 * 154 exposures = 0.3
takes by Level A harassment).
Because harbor seals typically inhabit areas closer to shore rather
than distances represented by the largest level B zone (39,811 m), NMFS
determined that the method above could underestimate potential take by
Level A harassment. NMFS accordingly estimated additional takes by
Level A harassment by determining the ratio of harbor seals that were
observed beyond the shutdown zone isopleth compared to the harbor seals
that were observed closer to construction activities during the EAS
fuel pier emergency repair that was completed in 2021 (i.e., 11/38 =
0.29 harbor seals). We then multiplied this ratio by the total number
of estimated harbor seal exposures to determine take by Level A
harassment (i.e., 0.29 * 154 exposures = 45) for a total of 45 takes by
Level A harassment (0.3 + 45 = 45.3).
For reasons described above, takes by Level B harassment were
modified to deduct the authorized amount of take by Level A harassment
(i.e., 154-45 = 109).
Therefore, NMFS proposes to authorize 45 takes by Level A
harassment and 109 takes by Level B harassment for harbor seal, for a
total of 154 takes.
Table 7--Authorized Take by Stock and Harassment Type and as a Percentage of Stock Abundance
----------------------------------------------------------------------------------------------------------------
Authorized take Authorized
-------------------------- take as a
Species Stock percentage
Level B Level A of stock
harassment harassment abundance
----------------------------------------------------------------------------------------------------------------
Fin Whale................................. Northeast Pacific............ 18 3 <1
Humpback Whale............................ Western North Pacific........ 3 1 <1
Mexico--North Pacific........ 9 2 1.2
Hawai[revaps]i............... 113 26 1.2
Minke Whale............................... Alaska....................... 5 3 <1
Sperm Whale............................... North Pacific................ 40 0 16.4
Baird's beaked whale...................... Alaska....................... 10 0 (*)
Stejneger's beaked whale.................. Alaska....................... 8 0 (*)
Killer whale.............................. ENP Alaska Resident Stock.... 176 0 9.2
ENP Gulf of Alaska, Aleutian 30
Islands, and Bering Seal.
Dall's Porpoise........................... Alaska....................... 26 13 <1
Harbor Porpoise........................... Bering Seal.................. 10 5 <1
Northern Fur Seal......................... Eastern Pacific.............. 5 0 <1
Steller Sea Lion.......................... Western, U.S................. 99 0 <1
Harbor Seal............................... Aleutian Islands............. 109 45 2.8
----------------------------------------------------------------------------------------------------------------
* Reliable abundance estimates for these stock are currently unavailable.
Mitigation
In order to issue an IHA under section 101(a)(5)(D) of the MMPA,
NMFS must set forth the permissible methods of taking pursuant to the
activity, and other means of effecting the least practicable impact on
the species or stock and its habitat, paying particular attention to
rookeries, mating grounds, and areas of similar significance, and on
the availability of the species or stock for taking for certain
subsistence uses (latter not applicable for this action). NMFS
regulations require applicants for incidental take authorizations to
include information about the availability and feasibility (economic
and technological) of equipment, methods, and manner of conducting the
activity or other means of effecting the least practicable adverse
impact upon the affected species or stocks, and their habitat (50 CFR
216.104(a)(11)).
In evaluating how mitigation may or may not be appropriate to
ensure the least practicable adverse impact on species or stocks and
their habitat, as well as subsistence uses where applicable, NMFS
considers two primary factors:
(1) The manner in which, and the degree to which, the successful
implementation of the measure(s) is expected to reduce impacts to
marine mammals, marine mammal species or stocks, and their habitat, as
well as subsistence uses. This considers the nature of the potential
adverse impact being mitigated (likelihood, scope,
[[Page 17434]]
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.
USAF must ensure that construction supervisors and crews, the
monitoring team and relevant USAF staff are trained prior to the start
of all pile driving and DTH activity, so that responsibilities,
communication procedures, monitoring protocols, and operational
procedures are clearly understood. New personnel joining during the
project must be trained prior to commencing work.
Mitigation for Marine Mammals and Their Habitat
Shutdown Zones--For all pile driving/removal and DTH activities,
USAF would implement shutdowns within designated zones. The purpose of
a shutdown zone is generally to define an area within which shutdown of
the activity would occur upon sighting of a marine mammal (or in
anticipation of an animal entering the defined area). Shutdown zones
vary based on the activity type and marine mammal hearing group (table
8). In most cases, the shutdown zones are based on the estimated Level
A harassment isopleth distances for each hearing group, as requested by
USAF. However, in cases where it would be challenging to detect marine
mammals at the Level A isopleth, (e.g., for high frequency cetaceans
and phocids during DTH activities and impact pile driving), smaller
shutdown zones have been established (table 8). Additionally, USAF has
agreed to implement a minimum shutdown zone of 25 m during all pile
driving and removal activities and DTH.
Finally, construction supervisors and crews, PSOs, and relevant
USAF staff must avoid direct physical interaction with marine mammals
during construction activity. If a marine mammal comes within 10 m of
such activity, operations must cease and vessels must reduce speed to
the minimum level required to maintain steerage and safe working
conditions, as necessary to avoid direct physical interaction. If an
activity is delayed or halted due to the presence of a marine mammal,
the activity may not commence or resume until either the animal has
voluntarily exited and been visually confirmed beyond the shutdown zone
indicated in table 8 or 15 minutes have passed for delphinids or
pinnipeds or 30 minutes for all other species without re-detection of
the animal.
Construction activities must be halted upon observation of a
species for which incidental take is not authorized or a species for
which incidental take has been authorized but the authorized number of
takes has been met entering or within the harassment zone.
Table 8--Shutdown Zones
--------------------------------------------------------------------------------------------------------------------------------------------------------
Shutdown zones (m)
Activity Pile diameter ----------------------------------------------------------------
LF MF HF PW OW
--------------------------------------------------------------------------------------------------------------------------------------------------------
Vibratory Installation or Removal............... 42-in................................ 50
-------------------------------------------------------------------------------------------------------
30-in................................ 25
--------------------------------------------------------------------------------------------------------------------------------------------------------
DTH............................................. 42-in................................ 2,600 100 500 400 100
30-in................................ 2,300 80 90
--------------------------------------------------------------------------------------------------------------------------------------------------------
Impact Pile..................................... 42-in................................ 2,100 80
30-in................................ 1,000 50 50
--------------------------------------------------------------------------------------------------------------------------------------------------------
Protected Species Observers--The number and placement of PSOs
during all construction activities (described in the Monitoring and
Reporting section) would ensure that the entire shutdown zone is
visible. USAF would employ at least two PSOs for all pile driving and
DTH activities.
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. If a marine mammal enters the Level B
harassment zone, PSOs will document the marine mammal's presence and
behavior.
Pre and Post-Activity Monitoring--Prior to the start of daily in-
water construction activity, or whenever a break in pile driving of 30
minutes or longer occurs, PSOs will observe the shutdown, Level A
harassment, and Level B harassment for a period of 30 minutes. Pre-
start clearance monitoring must be conducted during periods of
visibility sufficient for the lead PSO to determine that the shutdown
zones are clear of marine mammals. If the shutdown zone is obscured by
fog or poor lighting conditions, in-water construction activity will
not be initiated until the entire shutdown zone is visible. Pile
driving may commence following 30 minutes of observation when the
determination is made that the shutdown zones are clear of marine
mammals. If a marine mammal is observed entering or within shutdown
zones, pile driving activity must be delayed or halted. If pile driving
is delayed or halted due to the presence of a marine mammal, the
activity may not commence or resume until either the animal has
voluntarily exited and been visually confirmed beyond the shutdown zone
or 15 minutes have passed for delphinids or pinnipeds or 30 minutes
have passed for all other species without re-detection of the animal.
If a marine mammal for which Level B harassment take is authorized is
present in the Level B harassment zone, activities would begin and
Level B harassment take would be recorded.
Soft Start--The use of soft-start procedures are believed to
provide additional protection to marine mammals by providing warning
and/or giving marine mammals a chance to leave the area prior to the
hammer operating at full capacity. For impact pile driving, contractors
would be required to provide an initial set of three strikes from the
hammer at reduced energy, with each strike followed by a 30-second
waiting period. This
[[Page 17435]]
procedure would be conducted a total of three times before impact pile
driving begins. Soft start would be implemented at the start of each
day's impact pile driving and at any time following cessation of impact
pile driving for a period of 30 minutes or longer. Soft start is not
required during vibratory pile driving and removal activities.
Based on our evaluation of the applicant's planned measures, as
well as other measures considered by NMFS, NMFS has determined that the
planned 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.
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:
Occurrence of marine mammal species or stocks in the area
in which take is anticipated (e.g., presence, abundance, distribution,
density);
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);
Individual marine mammal responses (behavioral or
physiological) to acoustic stressors (acute, chronic, or cumulative),
other stressors, or cumulative impacts from multiple stressors;
How anticipated responses to stressors impact either: (1)
long-term fitness and survival of individual marine mammals; or (2)
populations, species, or stocks;
Effects on marine mammal habitat (e.g., marine mammal prey
species, acoustic habitat, or other important physical components of
marine mammal habitat); and,
Mitigation and monitoring effectiveness.
Visual Monitoring--Marine mammal monitoring must be conducted in
accordance with the Marine Mammal Monitoring and Mitigation Plan.
Marine mammal monitoring during pile driving and removal and DTH
activities must be conducted by NMFS-approved PSOs in a manner
consistent with the following:
PSOs must be independent of the activity contractor (for
example, employed by a subcontractor), and have no other assigned tasks
during monitoring periods;
At least one PSO must have prior experience performing the
duties of a PSO during construction activity pursuant to a NMFS-issued
incidental take authorization;
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.
Where a team of three or more PSOs is required, a lead
observer or monitoring coordinator will be designated. The lead
observer will be required to have prior experience working as a marine
mammal observer during construction activity pursuant to a NMFS-issued
incidental take authorization; and,
PSOs must be approved by NMFS prior to beginning any
activity subject to this IHA.
PSOs must also have the following additional qualifications:
Ability to conduct field observations and collect data
according to assigned protocols;
Experience or training in the field identification of
marine mammals, including identification of behaviors;
Sufficient training, orientation, or experience with the
construction operation to provide for personal safety during
observations;
Writing skills sufficient to prepare a report of
observations including, but not limited to, 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 note implemented when required);
and marine mammal behavior; and,
Ability to communicate orally, by radio or in person, with
project personnel to provide real-time information on marine mammals
observed in the area as necessary.
Visual monitoring will be conducted by a minimum of two trained
PSOs positioned at suitable vantage points. One PSO will have an
unobstructed view of all water within the shutdown zone and will be
stationed at or near the pier. Remaining PSOs will be placed at one or
more of the observer monitoring locations identified on figure 3-3 of
the marine mammal monitoring and mitigation plan, in order to observe
as much as the Level A and Level B harassment zone as possible. All
PSOs will have access to 20 by 60 spotting scope on a window mount or
tripod.
Monitoring will be conducted 30 minutes before, during, and 30
minutes after all in water construction activities. In addition, PSOs
will record all incidents of marine mammal occurrence, regardless of
distance from activity, and will document any behavioral reactions in
concert with distance from piles being driven or removed. Pile driving
activities include the time to install or remove a single pile or
series of piles, as long as the time elapsed between uses of the pile
driving equipment is no more than 30 minutes.
Reporting
USAF will submit a draft marine mammal monitoring report to NMFS
within 90 days after the completion of pile driving activities, or 60
days prior to a requested date of issuance of any future IHAs for the
project, or other projects at the same location, whichever comes first.
The marine mammal monitoring report will include an overall description
of work completed, a narrative regarding marine mammal sightings, and
associated PSO data sheets. Specifically, the report will include:
Dates and times (begin and end) of all marine mammal
monitoring;
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, DTH); (2) Total
duration of driving time for each pile (vibratory driving) and number
of strikes for each pile (impact driving); and (3) For DTH drilling,
duration of operation for both impulsive and non-pulse components;
PSO locations during marine mammal monitoring;
Environmental conditions during monitoring periods (at
beginning and
[[Page 17436]]
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;
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);
Number of marine mammals detected within the harassment
zones, by species; and,
Detailed information about implementation of any
mitigation (e.g., shutdowns and delays), a description of specific
actions that ensued, and resulting changes in behavior of the
animal(s), if any.
A final report must be prepared and submitted within 30 calendar
days following receipt of any NMFS comments on the draft report. If no
comments are received from NMFS within 30 calendar days of receipt of
the draft report, the report shall be considered final. All PSO
datasheets and/or raw sighting data would be submitted with the draft
marine mammal report.
In the event that personnel involved in the construction activities
discover an injured or dead marine mammal, the Holder must report the
incident to the Office of Protected Resources (OPR), NMFS
([email protected] and [email protected]) 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:
Time, date, and location (latitude/longitude) of the first
discovery (and updated location information if known and applicable);
Species identification (if known) or description of the
animal(s) involved;
Condition of the animal(s) (including carcass condition if
the animal is dead);
Observed behaviors of the animal(s), if alive;
If available, photographs or video footage of the
animal(s); and,
General circumstances under which the animal was
discovered.
Negligible Impact Analysis and Determination
NMFS has defined negligible impact as an impact resulting from the
specified activity that cannot be reasonably expected to, and is not
reasonably likely to, adversely affect the species or stock through
effects on annual rates of recruitment or survival (50 CFR 216.103). A
negligible impact finding is based on the lack of likely adverse
effects on annual rates of recruitment or survival (i.e., population-
level effects). An estimate of the number of takes alone is not enough
information on which to base an impact determination. In addition to
considering estimates of the number of marine mammals that might be
``taken'' through harassment, NMFS considers other factors, such as the
likely nature of any impacts or responses (e.g., intensity, duration),
the context of any impacts or responses (e.g., critical reproductive
time or location, foraging impacts affecting energetics), as well as
effects on habitat, and the likely effectiveness of the mitigation. We
also assess the number, intensity, and context of estimated takes by
evaluating this information relative to population status. Consistent
with the 1989 preamble for NMFS' implementing regulations (54 FR 40338,
September 29, 1989), the impacts from other past and ongoing
anthropogenic activities are incorporated into this analysis via their
impacts on the baseline (e.g., as reflected in the regulatory status of
the species, population size and growth rate where known, ongoing
sources of human-caused mortality, or ambient noise levels).
To avoid repetition, the majority of our analysis applies to all
the species listed in table 1, 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 DTH activities associated with the EAS fuel pier
repair project, as outlined previously, have the potential to disturb
or displace marine mammals. Specifically, the specified activities may
result in take, in the form of Level B harassment and, for some species
Level A harassment, from underwater sounds generated by pile driving
and DTH. Potential takes could occur if marine mammals are present in
zones ensonified above the thresholds for Level B harassment or Level A
harassment, identified above, while activities are underway.
No serious injury or mortality would be expected, even in the
absence of required mitigation measures, given the nature of the
activities. Further, no take by Level A harassment is anticipated for
otariids and mid-frequency cetaceans, due to the application of planned
mitigation measures, such as shutdown zones that encompass Level A
harassment zones for these species. The potential for harassment would
be minimized through the implementation of planned mitigation measures
(see Mitigation section).
Take by Level A harassment is authorized for six species (harbor
porpoise, Dall's porpoise, harbor seal, fin whale, humpback whale, and
minke whale) as the Level A harassment zone exceeds the size of the
shutdown zones (high frequency cetaceans and phocids), or, in the case
of low frequency cetaceans, the shutdown zone is so large that it is
possible that a minke whale, fin whale, or humpback whale could enter
the Level A harassment zone and remain within the zone for a duration
long enough to incur PTS before being detected.
Any take by Level A harassment is expected to arise from, at most,
a small degree of PTS (i.e., minor degradation of hearing capabilities
within regions of hearing that align most completely with the energy
produced by impact pile driving such as the low-frequency region below
2 kHz), not severe hearing impairment or impairment within the ranges
of greatest hearing sensitivity. Animals would need to be exposed to
higher levels and/or longer duration
[[Page 17437]]
than are expected to occur here in order to incur any more than a small
degree of PTS.
Given the small degree anticipated, any PTS potential incurred
would not be expected to affect the reproductive success or survival of
any individuals, much less result in adverse impacts on the species or
stock.
Additionally, some subset of the individuals that are behaviorally
harassed could also simultaneously incur some small degree of TTS for a
short duration of time. However, since the hearing sensitivity of
individuals that incur TTS is expected to recover completely within
minutes to hours, it is unlikely that the brief hearing impairment
would affect the individual's long-term ability to forage and
communicate with conspecifics, and would therefore not likely impact
reproduction or survival of any individual marine mammal, let alone
adversely affect rates of recruitment or survival of the species or
stock.
As described above, NMFS expects that marine mammals would likely
move away from an aversive stimulus, especially at levels that would be
expected to result in PTS, given sufficient notice through use of soft
start. USAF would also shut down pile driving activities if marine
mammals enter the shutdown zones (table 8) further minimizing the
likelihood and degree of PTS that would be incurred.
Effects on individuals that are taken by Level B harassment in the
form of behavioral disruption, on the basis of reports in the
literature as well as monitoring from other similar activities, would
likely be limited to reactions such as avoidance, increased swimming
speeds, increased surfacing time, or decreased foraging (if such
activity were occurring) (e.g., Thorson and Reyff, 2006). Most likely,
individuals would simply move away from the sound source and
temporarily avoid the area where pile driving is occurring. If sound
produced by project activities is sufficiently disturbing, animals are
likely to simply avoid the area while the activities are occurring. We
expect that any avoidance of the project areas by marine mammals would
be temporary in nature and that any marine mammals that avoid the
project areas during construction would not be permanently displaced.
Short-term avoidance of the project areas and energetic impacts of
interrupted foraging or other important behaviors is unlikely to affect
the reproduction or survival of individual marine mammals, and the
effects of behavioral disturbance on individuals is not likely to
accrue in a manner that would affect the rates of recruitment or
survival of any affected stock.
The project area does overlap a Biologically Important Area (BIA)
identified as important for feeding by sperm whale (Brower et al.,
2022). The BIA that overlaps the project area is active April through
September, which overlaps USAF's planned work period (April to
October). White the BIA is considered to be of higher importance, the
area of the BIA is very large, spanning the island chain, and the
project area is very small in comparison. Further sperm whales utilize
deeper waters to feed, and while the Level B harassment zone does
extend into deeper waters, the sound levels at the distances that
overlay deeper water where sperm whales might be foraging would be of
comparatively lower levels. Given the extensive options for high
quality foraging area near and outside of the project area, any impacts
to feeding sperm whales would not be expected to impact the survival or
reproductive success of any individuals.
The ensonified area also overlaps ESA-designated critical habitat
for western DPS Steller sea lion. Specifically, the Level B ensonified
area overlaps with the aquatic zones of three designated major haulouts
to the east and northwest of the project site: Shemya Island Major
Haulout, Alaid Island Major Haulout, Attu/Chirikof Point Major Haulout.
The ensonified area Level B harassment zone related to implementation
of the planned project, described in the Estimated Take of Marine
Mammals section, overlaps with the designated aquatic zone of all three
designated major haulouts.. No Steller sea lions have been observed on
Shemya Island Major Haulout (2.75 nm to the east of the project site)
during the most recent surveys (between 2015 and 2017) and only one
Steller sea lion was observed at Attu/Chirikof Point Major Haulout (24
nm northwest of the project site). An average of 68 non-pups and 7 pups
were observed annually during this time at Alaid Island Major Haulout,
which is 5 nautical miles northwest of the project site. The
construction site itself does not overlap with critical habitat. Take
by Level B harassment of steller sea lions has been authorized to
account for those that are occasionally observed in low numbers in
Alcan Harbor and Shemya Pass, however, the project is not expected to
have significant adverse impacts on Steller sea lion critical habitat.
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.
In summary and as described above, the following factors primarily
support our 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:
No serious injury or mortality is anticipated or
authorized;
No Level A harassment of six species is authorized;
Level A harassment takes authorized for six species are
expected to be of a small degree;
While impacts would occur within areas that are important
for feeding for sperm whale, because of the small footprint of the
activity relative to the area of these important use areas, we do not
expect impacts to the reproduction and survival of any individuals;
Effects on species that serve as prey for marine mammals
from the activities are expected to be short-term and, therefore, any
associated impacts on marine mammal feeding are not expected to result
in significant or long-term consequences for individuals, or to accrue
to adverse impacts on their populations;
The lack of anticipated significant or long-term negative
effects to marine mammal habitat; and,
The efficacy of the mitigation measures in reducing the
effects of the specified activities on all species and stocks.
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 planned monitoring and
mitigation measures, NMFS finds that the total marine mammal take from
the planned 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
[[Page 17438]]
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 instances of take NMFS proposes to authorize are below one-
third of the estimated stock abundance for all stocks (table 7). The
number of animals that we expect to authorize to be taken from these
stocks would be considered small relative to the relevant stocks'
abundances even if each estimated taking occurred to a new individual,
which is an unlikely scenario.
The best available abundance estimate for fin whale is not
considered representative of the entire stock as surveys were limited
to a small portion of the stock's range, but there are known to be over
2,500 fin whales in the northeast Pacific stock (Muto et al., 2021). As
such, the 18 takes by Level B harassment and 3 takes by Level A
harassment authorized, compared to the abundance estimate, shows that
less than 1 percent of the stock would be expected to be impacted.
The most recent abundance estimate for the Mexico-North Pacific
stock of humpback whale is likely unreliable as it is more than 8 years
old. The most relevant estimate of this stock's abundance in the Bering
Sea and Aleutian Islands is 918 humpback whales (Wade, 2021), so the 9
authorized takes by Level B harassment and 2 authorized takes by Level
A harassment, is small relative to the estimated abundance (1.2
percent), even if each authorized take occurred to a new individual.
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), so the 5
authorized takes by Level B harassment, and 3 authorized takes by Level
A harassment, compared to the abundance estimate, shows that less than
1 percent of the stock would be expected to be impacted.
The most recent abundance estimate for sperm whale in the North
Pacific is likely unreliable as it is more than 8 years old and was
derived from data collected in a small area that may not have included
females and juveniles, and did not account for animals missed on the
trackline. The minimum population estimate for this stock is 244 sperm
whales, so the 40 authorized takes by Level B harassment is small
relative to the estimated survey abundance, even if each authorized
take occurred to a new individual.
There is no abundance information available for any Alaskan stock
of beaked whale. However, the take numbers are sufficiently small (8
and 10 takes by Level B harassment for Stejneger's beaked whale and
Baird's beaked whale, respectively) that we can safely assume that they
are small relative to any reasonable assumption of likely population
abundance for these stocks. For reference, current abundance estimates
for other beaked whale stocks in the Pacific include 1,363 Baird's
beaked whales (California/Oregon/Washington stock), 3,044 Mesoplodont
beaked whales (CA/OR/WA stock), 5,454 Cuvier's beaked whales (CA/OR/WA
stock), 564 Blainville's beaked whales (Hawai'i Pelagic stock), 2,550
Longman's beaked whales (Hawai`i stock), and 3,180 Cuvier's beaked
whales (Hawai'i Pelagic stock).
The Alaska stock of Dall's porpoise has no official NMFS abundance
estimate for this area, as the most recent estimate is greater than 8
years old. The most recent estimate was 13,110 animals for just a
portion of the stock's range. Therefore, the 26 takes by Level B
harassment and 13 takes by Level A harassment authorized for this
stock, compared to the abundance estimate, shows that less than 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 10 takes by Level B harassment
authorized for the stock, and 5 takes by Level A harassment authorized
for the stock, compared to the abundance estimate, which is only a
portion of the Bering Sea Stock, shows that, at most, less than 1
percent of the stock would be expected to be impacted.
Based on the analysis contained herein of the planned activity
(including the planned mitigation and monitoring measures) and the
anticipated take of marine mammals, NMFS 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.
No subsistence hunting occurs on Shemya Island, which is a USAF Air
Station; Access to the island is only provided by military aircraft and
USAF-contracted charter planes for crews and workers. The nearest
community that engages in subsistence hunting is located on Adak,
Alaska which is 640 km (399 mi) to the east. Historically, an Alaska
Native community on Attu, 60 km (37 mi) to the west, hunted for
subsistence, but that community was destroyed during WWII and the
residents that survived internment did not return to the island.
Based on the description of the specified activity, NMFS has
determined that there will not be an unmitigable adverse impact on
subsistence uses from USAF's planned activities.
Endangered Species Act
Section 7(a)(2) of the 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 consults internally whenever
we propose to authorize take for endangered or threatened species, in
this case with the Alaska Regional Office.
[[Page 17439]]
There are four marine mammal species (northeast Pacific fin whale,
Mexico-North Pacific and western North Pacific humpback whale, North
Pacific sperm whale, and western DPS Steller sea lion) with confirmed
occurrence in the project area that are listed as endangered under the
ESA. The NMFS Alaska Regional Office Protected Resources Division
issued a Biological Opinion on March 1, 2024 under section 7 of the
ESA, on the issuance of an IHA to USAF under section 101(a)(5)(D) of
the MMPA by the NMFS Permits and Conservation Division. The Biological
Opinion concluded that the proposed action is not likely to jeopardize
the continued existence of northeast Pacific fin whale, Mexico Pacific
and western North Pacific humpback whale, North Pacific sperm whale,
and western DPS Steller sea lion and is not likely to destroy or
adversely modify western DPS Steller sea lion critical habitat.
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 evaluate our proposed action (i.e., the issuance of an IHA)
and alternatives with respect to potential impacts on the human
environment. This action is consistent with categories of activities
identified in Categorical Exclusion B4 (IHAs with no anticipated
serious injury or mortality) of the Companion Manual for NAO 216-6A,
which do not individually or cumulatively have the potential for
significant impacts on the quality of the human environment and for
which we have not identified any extraordinary circumstances that would
preclude this categorical exclusion. Accordingly, NMFS has determined
that the issuance of this IHA qualifies to be categorically excluded
from further NEPA review.
Authorization
NMFS has issued an IHA to USAF for the potential harassment of
small numbers of 12 marine mammal species incidental to the Eareckson
Air Station (EAS) Fuel Pier Repair in Alcan Harbor, Shemya Island,
Alaska, that includes the previously explained mitigation, monitoring
and reporting requirements.
Dated: March 6, 2024.
Catherine G. Marzin,
Deputy Director, Office of Protected Resources, National Marine
Fisheries Service.
[FR Doc. 2024-05105 Filed 3-8-24; 8:45 am]
BILLING CODE 3510-22-P