[Federal Register Volume 90, Number 71 (Tuesday, April 15, 2025)]
[Notices]
[Pages 15697-15709]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2025-06376]
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DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
[RTID 0648-XE724]
Takes of Marine Mammals Incidental to Specified Activities;
Taking Marine Mammals Incidental to Small Boat Harbor Preconstruction
Activities (Geotechnical Surveys) in St. George, 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 United States Army Corps of Engineers (USACE) to incidentally
harass marine mammals during geotechnical drilling in St. George,
Alaska.
DATES: This authorization is effective from April 15, 2025 through June
15, 2025.
ADDRESSES: Electronic copies of the application and supporting
documents, as well as a list of the references cited in this document,
may be obtained online at: 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 monitoring and
reporting of the takings. The definitions of all applicable MMPA
statutory terms used above are included in the relevant sections below
and can be found in section 3 of the MMPA (16 U.S.C. 1362) and NMFS
regulations at 50 CFR 216.103.
Summary of Request
On October 30, 2024, NMFS received a request from USACE for an IHA
to take marine mammals incidental to geotechnical surveys to be
conducted as part of preconstruction activities associated with a new
small boat harbor in St. George, Alaska. Following NMFS' review of the
application, and discussions between NMFS and USACE, the application
was deemed adequate and complete on January 29, 2025. The USACE
submitted a final revised version on February 19, 2025. The USACE's
request is for take of northern fur seal, by Level A and Level B
harassment and, of harbor seal, by Level B harassment only. Neither
USACE nor NMFS expect serious injury or mortality to result from this
activity and, therefore, an IHA is appropriate.
This IHA covers preconstruction activity associated with a larger
project involving construction of a new small boat harbor.
Description of the Specified Activity
The USACE is in the preconstruction, engineering, and design phase
for constructing a small boat harbor in St. George, Alaska. Between
April 15, 2025 and June 15, 2025, USACE plans to conduct large
penetration testing (LPT) and borehole drilling at 15 sites in the
embayment between the Old Jetty west to North Rookery. USACE estimates
that one hole will be completed each day, with the boring component
taking 10 hours and the LPT component taking 1 hour. These methods
would introduce underwater sounds that may result in take, by Level A
and Level B harassment, of marine mammals.
[[Page 15698]]
A detailed description of the planned geotechnical surveys project
is provided in the Federal Register notice for the proposed IHA (90 FR
11282; March 5, 2025). 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 USACE was published
in the Federal Register on March 5, 2025 (90 FR 11282). That notice
described, in detail, USACE'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, NMFS received comments
from one commenter. NMFS' responses are provided below and all comments
are available online at: https://www.fisheries.noaa.gov/national/marine-mammal-protection/incidental-take-authorizations-construction-activities. Please see the comment submission for full details
regarding the recommendations and supporting rationale.
Comment 1: A member of the public asserted that noise generated by
the USACE's geotechnical surveys and use of a barge to transport and
hold equipment has the potential to interfere with marine mammals. The
commenter describes a variety of behavioral effects that anthropogenic
noise can have on marine mammals, including flight response and
masking, and that these responses can disrupt migration, communication
and feeding. The commenter describes the detrimental impacts that would
occur should the project lead to the reduction of prominent predators
in the area (i.e., killer whale and pinnipeds), and provides a
description of trophic cascades. The commenter acknowledges the project
is not long term in duration but suggests the project generates noise
at frequencies that could impede mammalian function and potentially
lead to death due to limited hunting ability, stress, or migration. The
commenter suggests a resulting imbalance could impact the Alaskan
seafood industry.
Response: NMFS appreciates the commenter's engagement in the IHA
process, but notes that the commenter included a number of factual
errors when describing the geotechnical surveys that constitute the
small boat harbor preconstruction project in St. George, Alaska. The
project activities and associated sound levels are described in the
Federal Register notice for the proposed IHA (90 FR 11282; March 5,
2025). NMFS also clarifies that the harassment of killer whales is
neither anticipated nor authorized in the IHA.
As described in the proposed IHA (90 FR 11282, March 5, 2025), NMFS
finds that marine mammal harassment associated with this project would
be limited to harbor seal and northern fur seal, and the most likely
impacts would be limited to short-term avoidance 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 geotechnical surveys, which are
planned for no more than 15 days, would not be permanently displaced.
Additionally, indirect effects on marine mammal prey during the
geotechnical surveys are expected to be minor, and these effects are
unlikely to cause substantial effects on marine mammals at the
individual level. NMFS notes that mitigation and monitoring prescribed
will affect the least practicable adverse impact on marine mammals and
their habitat.
Comment 2: The commenter expresses concern that the construction of
the small boat harbor would reduce habitat for pinnipeds.
Response: NMFS appreciates the commenter's concerns regarding
future small boat harbor construction but notes that NMFS' analysis is
limited to small boat harbor preconstruction activities (geotechnical
surveys). Should NMFS receive an application to harass marine mammals
incidental to the construction of a small boat harbor at St. George,
Alaska, NMFS will assess the impacts of the USACE's proposed activities
on mammals and their habitat and only authorize take if NMFS is able to
make the necessary findings to support the issuance of an
authorization.
Comment 3: The commenter expresses concern that the future
construction of a small boat harbor will increase the number of boats
frequenting the area and that this will increase risk of vessel strikes
and pollution, such as sewage, wastewater, bilge water, and trash. The
commenter calls for increased boater safety regulations and pollution
control within the harbor.
Response: NMFS appreciates the commenter's concerns regarding
future small boat harbor construction but notes that NMFS' analysis is
limited to small boat harbor preconstruction activities (geotechnical
surveys). NMFS notes concerns regarding boating safety and pollution
are outside NMFS' purview under the MMPA.
Comment 4: The commenter calls for mitigation of the environmental
impacts associated with the planned geotechnical drilling and
implementation of a new harbor. The commenter provides some
suggestions, which include: the establishment of Marine Protected
Areas, increasing boating regulations, and using quieter drilling
techniques to limit noise disturbance.
Response: NMFS concurs with the commenter's general recommendation
to require mitigation to minimize impacts to marine mammals and their
habitats, though the commenter's specific suggestions for mitigation
are outside NMFS' purview under the MMPA. The USACE will establish
shutdown zones and employ PSOs to monitor Level A and Level B
harassment, conduct pre and post-activity monitoring, and implement
shutdowns as necessary. PSOs will also observe, record, and report on
the presence of marine mammals in the project area and at North
Rookery, and include this information in a report to inform future
decision-making. Please see the Mitigation and Monitoring and Reporting
sections of this final IHA for additional details
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
[[Page 15699]]
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 (M/SI)
from anthropogenic sources are included here as gross indicators of the
status of the species or stocks and other threats.
Marine mammal abundance estimates presented in this document
represent the total number of individuals that make up a given stock or
the total number estimated within a particular study or survey area.
NMFS' stock abundance estimates for most species represent the total
estimate of individuals within the geographic area, if known, that
comprises that stock. For some species, this geographic area may extend
beyond U.S. waters. All managed stocks in this region are assessed in
NMFS' U.S. Alaska SARs. All values presented in table 1 are the most
recent available at the time of publication (including from the draft
2024 SARS) and are available online at: https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessments.
Table 1--Species \1\ That May Be 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/
\2\ abundance survey) \3\ S \4\
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Order--Odontoceti (toothed whales, dolphins, and porpoises)
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Family Delphinidae:
Killer whale.................... Orcinus orca........... Eastern North Pacific -, -, N 1920 (N/A, 1,920, 19 1.3
Alaska Resident. 2019) \5\.
Eastern North Pacific -, -, N 587 (N/A, 587, 2012) 5.9 0.8
Gulf of Alaska, \5\.
Aleutian Islands and
Bering Sea Transient.
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Order Carnivora--Pinnipedia
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Family Otariidae (eared and sea
lions):
Northern fur seal............... Callorhinus ursinus.... Eastern Pacific........ -, D, Y 612,765 \6\ (0.2, 11,151 296
518,651, 2022).
Steller's sea lion.............. Eumetopias jubatus..... Western................ E, D, Y 49,837 (N/A, 49,837, 299 267
2022) \7\.
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Family Phocidae (earless seals):
Harbor seal..................... Phoca vitulina......... Pribilof Islands....... -, -, N 229 \8\ (N/A, 229, 7 0
2018).
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\1\ Information on the classification of marine mammal species can be found on the web page for The Society for Marine Mammalogy's Committee on
Taxonomy; [https://marinemammalscience.org/science-and-publications/list-marine-mammal-species-subspecies)].
\2\ Endangered Species Act (ESA) status: Endangered (E), Threatened (T)/MMPA status: Depleted (D). A dash (-) indicates that the species is not listed
under the ESA or designated as depleted under the MMPA. Under the MMPA, a strategic stock is one for which the level of direct human-caused mortality
exceeds PBR or which is determined to be declining and likely to be listed under the ESA within the foreseeable future. Any species or stock listed
under the ESA is automatically designated under the MMPA as depleted and as a strategic stock.
\3\ NMFS marine mammal stock assessment reports online at https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessment-reports-region. CV is coefficient of variation; Nmin is the minimum estimate of stock abundance.
\4\ These values, found in NMFS's SARs, represent annual levels of human-caused mortality plus serious injury from all sources combined (e.g.,
commercial fisheries, ship strike). Annual M/SI often cannot be determined precisely and is in some cases presented as a minimum value or range.
\5\ Nest is based upon counts of individuals identified from photo-ID catalogs.
\6\ Survey years = Sea Lion Rock-2014; St. Paul Is.--2018, 2021, 2022; and St. George Is--2018, 2022; Bogoslof Is.--2019.
\7\ Nest is best estimate of counts, which have not been corrected for animals at sea during abundance surveys. Estimates provided are for the U.S.
only. The overall Nmin is 73,211 and overall PBR is 439.
\8\ Nest is best estimate of counts, which have not been corrected for animals at sea during abundance surveys.
Marine Mammal Hearing
Hearing is the most important sensory modality for marine mammals
underwater, and exposure to anthropogenic sound can have deleterious
effects. To appropriately assess the potential effects of exposure to
sound, it is necessary to understand the frequency ranges marine
mammals are able to hear. Not all marine mammal species have equal
hearing capabilities (e.g., Richardson et al., 1995; Wartzok and
Ketten, 1999; Au and Hastings, 2008). To reflect this, Southall et al.
(2007, 2019) recommended that marine mammals be divided into hearing
groups based on directly measured (behavioral or auditory evoked
potential techniques) or estimated hearing ranges (behavioral response
data, anatomical modeling, etc.). Generalized hearing ranges were
chosen based on the ~65 decibel (dB) threshold from composite
audiograms, previous analyses in NMFS (2018), and/or data from Southall
et al. (2007) and Southall et al. (2019). We note that the names of two
hearing groups and the generalized hearing ranges of all marine mammal
hearing groups have been recently updated (NMFS 2024) as reflected
below in table 2.
Table 2--Marine Mammal Hearing Groups
[NMFS, 2024]
------------------------------------------------------------------------
Hearing group Generalized hearing range *
------------------------------------------------------------------------
Low-frequency (LF) cetaceans (baleen 7 Hz to 36 kHz **.
whales).
High-frequency (HF) cetaceans 150 Hz to 160 kHz.
(dolphins, toothed whales, beaked
whales, bottlenose whales).
[[Page 15700]]
Very High-frequency (VHF) cetaceans 200 Hz to 165 kHz.
(true porpoises, Kogia, river
dolphins, Cephalorhynchid,
Lagenorhynchus cruciger & L.
australis).
Phocid pinnipeds (PW) (underwater) 40 Hz to 90 kHz.
(true seals).
Otariid pinnipeds (OW) (underwater) 60 Hz to 68 kHz.
(sea lions and fur seals).
------------------------------------------------------------------------
* Represents the generalized hearing range for the entire group as a
composite (i.e., all species within the group), where individual
species' hearing ranges may not be as broad. Generalized hearing range
chosen based on ~65 dB threshold from composite audiogram, previous
analysis in NMFS 2018, and/or data from Southall et al. 2007; Southall
et al. 2019. Additionally, animals are able to detect very loud sounds
above and below that ``generalized'' hearing range.
** Hertz (Hz) and Kilohertz (kHz).
For more detail concerning these groups and associated frequency
ranges, please see NMFS (2024) for a review of available information.
Potential Effects of Specified Activities on Marine Mammals and Their
Habitat
The effects of underwater noise from 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 (90 FR
11282, March 5, 2025) included a discussion of the effects of
anthropogenic noise on marine mammals and the potential effects of
underwater noise from USACE's geotechnical survey activity on marine
mammals and their habitat. That information and analysis is referenced
in this final IHA determination and is not repeated here; please refer
to the notice of proposed IHA (90 FR 11282, March 5, 2025).
Estimated Take of Marine Mammals
This section provides an estimate of the number of incidental takes
authorized through the IHA, which will inform NMFS' consideration of
``small numbers,'' the negligible impact determinations, and impacts on
subsistence uses.
Harassment is the only type of take expected to result from these
activities. Except with respect to certain activities not pertinent
here, section 3(18) of the MMPA defines ``harassment'' as any act of
pursuit, torment, or annoyance, which (i) has the potential to injure a
marine mammal or marine mammal stock in the wild (Level A harassment);
or (ii) has the potential to disturb a marine mammal or marine mammal
stock in the wild by causing disruption of behavioral patterns,
including, but not limited to, migration, breathing, nursing, breeding,
feeding, or sheltering (Level B harassment).
Authorized takes are primarily by Level B harassment, as use of
acoustic sources (LPT and borehole drilling) has the potential to
result in disruption of behavioral patterns for individual marine
mammals. There is also some potential for auditory injury (AUD INJ)
(Level A harassment) to result, for northern fur seal because fur seals
are common in the immediate vicinity of the planned activity and
predicted AUD INJ are larger than planned shutdown zones. AUD INJ is
unlikely to occur for other species. The planned 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 criteria above which NMFS believes the best
available science indicates marine mammals will likely be behaviorally
harassed or incur some degree of AUD INJ; (2) the area or volume of
water that will be ensonified above these levels in a day; (3) the
density or occurrence of marine mammals within these ensonified areas;
and, (4) the number of days of activities. We note that while these
factors can contribute to a basic calculation to provide an initial
prediction of potential takes, additional information that can
qualitatively inform take estimates is also sometimes available (e.g.,
previous monitoring results or average group size). Below, we describe
the factors considered here in more detail and present the take
estimates.
Acoustic Criteria
NMFS recommends the use of acoustic criteria that identify the
received level of underwater sound above which exposed marine mammals
would be reasonably expected to be behaviorally harassed (equated to
Level B harassment) or to incur AUD INJ of some degree (equated to
Level A harassment). We note that the criteria for AUD INJ, as well as
the names of two hearing groups, have been recently updated (NMFS 2024)
as reflected below in the Level A harassment section.
Level B Harassment--Though significantly driven by received level,
the onset of behavioral disturbance from anthropogenic noise exposure
is also informed to varying degrees by other factors related to the
source or exposure context (e.g., frequency, predictability, duty
cycle, duration of the exposure, signal-to-noise ratio, distance to the
source), the environment (e.g., bathymetry, other noises in the area,
predators in the area), and the receiving animals (hearing, motivation,
experience, demography, life stage, depth) and can be difficult to
predict (e.g., Southall et al., 2007, 2021; Ellison et al., 2012).
Based on what the available science indicates and the practical need to
use a threshold based on a metric that is both predictable and
measurable for most activities, NMFS typically uses a generalized
acoustic threshold based on received level to estimate the onset of
behavioral harassment. NMFS generally predicts that marine mammals are
likely to be behaviorally harassed in a manner considered to be Level B
harassment when exposed to underwater anthropogenic noise above root-
mean-squared pressure received levels (RMS SPL) of 120 dB (referenced
to 1 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 temporary threshold shift (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
[[Page 15701]]
reduced opportunities to detect important signals (conspecific
communication, predators, prey) may result in changes in behavior
patterns that would not otherwise occur.
USACE's geotechnical survey activities includes the use of
continuous (borehole drilling) and impulsive (LPT) sources, and
therefore the RMS SPL thresholds of 120 and 160 dB re 1 [mu]Pa,
respectively are applicable.
Level A Harassment--NMFS' Updated Technical Guidance for Assessing
the Effects of Anthropogenic Sound on Marine Mammal Hearing (Version
3.0) (Updated Technical Guidance, 2024) identifies dual criteria to
assess AUD INJ (Level A harassment) to five different underwater marine
mammal groups (based on hearing sensitivity) as a result of exposure to
noise from two different types of sources (impulsive or non-impulsive).
USACE's planned activity includes the use of impulsive (i.e., LPT) and
non-impulsive (i.e., borehole drilling) sources.
The 2024 Updated Technical Guidance criteria include both updated
thresholds and updated weighting functions for each hearing group. The
thresholds are provided in table 3. The references, analysis, and
methodology used in the development of the criteria are described in
NMFS' 2024 Updated Technical Guidance, which may be accessed at:
https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-acoustic-technical-guidance-other-acoustic-tools.
Table 3--Thresholds Identifying the Onset of Auditory Injury
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AUD INJ onset acoustic thresholds * (received level)
Hearing group ------------------------------------------------------------------------
Impulsive Non-impulsive
----------------------------------------------------------------------------------------------------------------
Low-Frequency (LF) Cetaceans........... Cell 1: Lpk,flat: 222 dB; Cell 2: LE,LF,24h: 197 dB.
LE,LF,24h: 183 dB.
High-Frequency (HF) Cetaceans.......... Cell 3: Lpk,flat: 230 dB; Cell 4: LE,HF,24h: 201 dB.
LE,HF,24h: 193 dB.
Very High-Frequency (VHF) Cetaceans.... Cell 5: Lpk,flat: 202 dB; Cell 6: LE,VHF,24h: 181 dB.
LE,VHF,24h: 159 dB.
Phocid Pinnipeds (PW) (Underwater)..... Cell 7: Lpk,flat: 223 dB; Cell 8: LE,PW,24h: 195 dB.
LE,PW,24h: 183 dB.
Otariid Pinnipeds (OW) (Underwater).... Cell 9: Lpk,flat: 230 dB; Cell 10: LE,OW,24h: 199 dB.
LE,OW,24h: 185 dB.
----------------------------------------------------------------------------------------------------------------
* Dual metric criteria for impulsive sounds: Use whichever criteria results in the larger isopleth for
calculating AUD INJ onset. If a non-impulsive sound has the potential of exceeding the peak sound pressure
level criteria associated with impulsive sounds, the PK SPL criteria are recommended for consideration for non-
impulsive sources.
Note: Peak sound pressure level (Lp,0-pk) has a reference value of 1 [mu]Pa, and weighted cumulative sound
exposure level (LE,p) has a reference value of 1 [mu]Pa\2\s. In this table, criteria are abbreviated to be
more reflective of International Organization for Standardization (ISO) standards (ISO 2017; ISO 2020). The
subscript ``flat'' is being included to indicate peak sound pressure are flat weighted or unweighted within
the generalized hearing range of marine mammals underwater (i.e., 7 Hz to 165 kHz). The subscript associated
with cumulative sound exposure level criteria indicates the designated marine mammal auditory weighting
function (LF, HF, and VHF cetaceans, and PW and OW pinnipeds) and that the recommended accumulation period is
24 hours. The weighted cumulative sound exposure level criteria could be exceeded in a multitude of ways
(i.e., varying exposure levels and durations, duty cycle). When possible, it is valuable for action proponents
to indicate the conditions under which these criteria will be exceeded.
Ensonified Area
Here, we describe operational and environmental parameters of the
activity that are used in estimating the area ensonified above the
acoustic thresholds, including source levels and transmission loss
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., LPT and borehole drilling).
Sound Source Levels of Planned Activities--The intensity of
geotechnical survey activity sounds is greatly influenced by factors
such as the size of hammers and the physical environment (e.g.,
sediment type) in which the activity takes place. The USACE evaluated
sound source level (SL) measurements available for similar geotechnical
surveys to determine suitable proxies for the planned activities. The
proxy source levels initially proposed by USACE were less conservative
compared to what might be realized by the actual activities taking
place, as the values were derived in one case, from a project that was
conducted in a dissimilar sediment type from a jacked up drill rig, and
in another case, from a project that did not report its parameters and
environmental characteristics. NMFS has instead relied on alternative
proxy SLs in our evaluation of the impacts of the USACE's planned
activities (table 1 in the proposed FRN) on marine mammals, with USACE
concurrence.
Table 4--Estimates of Mean Underwater Sound Levels Generated During Geotechnical Surveys
--------------------------------------------------------------------------------------------------------------------------------------------------------
Reference
dB RMS dB Peak dB SEL distance (m) Reference
--------------------------------------------------------------------------------------------------------------------------------------------------------
LPT......................................... 197 213 182 1 Huang et al., 2023.
Borehole Drilling........................... 155.9 N/A N/A
--------------------------------------------------------------------------------------------------------------------------------------------------------
Note: dB peak = peak sound level; rms = root mean square; SEL = sound exposure level.
Transmission Loss (TL) is the decrease in acoustic intensity as an
acoustic pressure wave propagates out from a source. TL parameters vary
with frequency, temperature, sea conditions, current, source and
receiver depth, water depth, water chemistry, and bottom composition
and topography. The general formula for underwater TL is:
TL = B x Log10 (R1/R2),
where
TL = transmission loss in dB
B = transmission loss coefficient
R1 = the distance of the modeled SPL from the driven
pile, and
R2 = the distance from the driven pile of the initial
measurement
Absent site-specific acoustical monitoring with differing measured
TL, a practical spreading value of 15 is used
[[Page 15702]]
as the TL coefficient in the above formula. Site-specific TL data for
the Sitka Sound are not available; therefore, the default coefficient
of 15 is used to determine the distances to the Level A harassment and
Level B harassment thresholds.
The ensonified area associated with Level A harassment is more
technically challenging to predict due to the need to account for a
duration component. Therefore, NMFS developed an optional User
Spreadsheet tool to accompany the 2024 Updated Technical Guidance that
can be used to relatively simply predict an isopleth distance for use
in conjunction with marine mammal density or occurrence to help predict
potential takes. We note that because of some of the assumptions
included in the methods underlying this optional tool, we anticipate
that the resulting isopleth estimates are typically going to be
overestimates of some degree, which may result in an overestimate of
potential take by Level A harassment. However, this optional tool
offers the best way to estimate isopleth distances when more
sophisticated modeling methods are not available or practical. For
stationary sources such as geotechnical survey activities (LPT and
borehole drilling), the optional User Spreadsheet tool predicts the
distance at which, if a marine mammal remained at that distance for the
duration of the activity, it would be expected to incur AUD INJ. Inputs
used in the optional User Spreadsheet tool (e.g., number of holes per
day, duration, and strikes/hole) are presented in table 5 and the
resulting estimated isopleths, are reported below in table 6.
Table 5--User Spreadsheet Inputs
------------------------------------------------------------------------
Impact Vibratory
---------------------------------------
LPT Borehole drilling
------------------------------------------------------------------------
Spreadsheet Tab Used............ E.1) Impact Pile A.1) Vibratory
Driving. Pile Driving.
Sound Source Level (SL)......... 182 SEL........... 155.9 RMS.
---------------------------------------
Transmission Loss Coefficient... 15
---------------------------------------
Weighting Factor Adjustment 2................. 2.5.
(kHz).
Activity Duration per day 60................ 540.
(minutes).
Number of strikes per pile...... 3,600............. N/A.
---------------------------------------
Number of piles per day......... 1
---------------------------------------
Distance of sound pressure level 1
measurement.
------------------------------------------------------------------------
Table 6--Level A Harassment and Level B Harassment Isopleths and Associated Areas From Geotechnical Surveys
--------------------------------------------------------------------------------------------------------------------------------------------------------
Level A harassment: isopleths (m) Level B
Activity type -------------------------------------------------------------------------------- harassment
LF HF VHF PW OW isopleth (m)
--------------------------------------------------------------------------------------------------------------------------------------------------------
LPT..................................................... 200.5 25.6 310.2 178.1 66.4 293
Drilling................................................ 1.8 0.7 1.5 2.3 0.8 247
--------------------------------------------------------------------------------------------------------------------------------------------------------
Abbreviations: LF = low-frequency cetaceans, HF = high-frequency cetaceans, VHF = very high-frequency cetaceans, PW = phocid pinnipeds in water, OW =
otariid pinnipeds in water.
Level A harassment zones are typically smaller than Level B
harassment zones. Calculation of Level A harassment isopleths include a
duration component, which in the case of LPT, is estimated through the
total number of daily strikes and the associated pulse duration. For a
stationary sound source such as LPT, we assume there that an animal is
exposed to all of the strikes expected within a 24-hour period.
Calculation of a Level B harassment zone does not include a duration
component.
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 also describe how the information
provided above is synthesized to produce a quantitative estimate of the
take that is reasonably likely to occur and authorized.
Potential exposures to LPT and borehole drilling noise for each
acoustic threshold were estimated using data reported by the USACE from
monitoring events conducted on 5 days across April and June 2024 (table
7). Northern fur seal were the only pinnipeds observed on land. The
USACE reported an estimate of a single daily point count of the number
of northern fur seals present at north rookery and along the shoreline
towards the Old Jetty. For pinnipeds observed in the water (northern
fur seal, Steller sea lion, and harbor seal), USACE reported the total
number of each species observed over the course of a day. Individual
sightings of pinniped groups in the water were not reported. Northern
fur seal in the water were described to be moving from west to east.
Steller sea lion were described to be observed near the Old Jetty in
groups up to 8 to 10, and were passing through rather than lingering.
On 3 days, groups of up to eight harbor seal were observed inside the
Old Jetty.
[[Page 15703]]
Table 7--Monitoring Data Collected and Reported by USACE Between Old Jetty and North Rookery in 2024
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Daily total marine mammals observed in water Daily estimates of marine mammals observed on land
Hours of Total hours of \1\ ---------------------------------------------------------------------------
Date observation observation ------------------------------------------------
NOFS HASL STSL NOFS \2\ HASL STSL
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
4/23/2024........................... 14:30-22:00 7.5 16 6 3 No Data................. No Data................ No Data.
4/24/2024........................... 08:15-22:30 14.25 22 8 11 126..................... 0...................... 0.
4/25/2024........................... 08:30-23:45 15.25 32 3 14 No Data................. No Data................ No Data.
6/14/2024........................... 18:00-0000 6 98 0 5 245..................... 0...................... 0.
6/15/2024........................... 09:00-23:45 13.75 110 0 4 300..................... 0...................... 0.
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ Individual sightings of groups of marine mammals throughout the observation period were not reported.
\2\ The USACE indicated that they counted northern fur seal hauled out along approximately \1/3\ of the rookery and extrapolated this number to estimate the total number of seals present along
the rest of the shoreline.
The take estimate was determined using the following equation: take
estimate = number of expected animals * number of planned survey days.
Northern Fur Seal
Initially, the USACE used both land-based and in-water counts to
estimate the number of expected northern fur seals to be taken each
survey day. For the six boreholes closest to North Rookery, USACE used
the maximum number estimated on the beach across all five surveys (n =
300) and maximum number estimated in the water across all five surveys
(n = 110). For the remaining nine boreholes, USACE assumed half the
maximum number on the shore across all five surveys would be taken (n =
150) and the maximum number estimated in the water across all five
surveys (n = 110). NMFS agrees with USACE's rationale for estimating
take using on-land numbers, but disagrees that in-water counts should
be used in take estimates. These observations were not recorded in
concert with land-based observations and as such would double-count the
number of northern fur seals that might be taken. Additionally since
fine-scale data regarding pinniped use in the area are not available,
NMFS finds that it is more appropriate to base take estimates on the
maximum number estimated on land for all borehole locations and the
USACE agreed. The USACE concurred with this approach. As noted
previously, NMFS assumes, that the number of hauled out northern fur
seals at north rookery represent approximately one-third of the total
population of northern fur seal in the area (Williams 2024, personal
communication), and as such, the maximum count of land-based seals is
multiplied by 3. As such, a total of 13,500 takes by Level B harassment
of northern fur seal are authorized (15 construction days x 300
northern fur seals * 3 = 13,500 takes by Level B harassment.
During LPT activities, the Level A harassment zone (66.4 m) is
larger than the shutdown zone (50 m) for northern fur seal. As such,
and given the frequent occurrence of fur seals in the immediate
vicinity of the project area, it is possible that northern fur seal may
enter the Level A harassment zone and stay long enough to incur AUD INJ
before exiting. The ratio of the Level A harassment area that exceeds
the shutdown zone (0.007 square kilometers (km\2\)) to the largest
Level B harassment area (0.27 km\2\) is 0.026. This activity is
predicted to take place 10 percent of each survey day. As such, 35
takes by Level A harassment are authorized (0.026 x 900 northern fur
seal x 15 survey days x .10 = 35 takes by Level A harassment).
Any individuals exposed to the higher levels associated with the
potential for permanent threshold shift (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 a
take by both Level A harassment and Level B harassment. Therefore, NMFS
authorized 35 takes by Level A harassment and 13,465 takes by Level B
harassment for northern fur seal, for a total of 13,500 takes.
Harbor Seal
To estimate take for harbor seal, USACE used the maximum number of
harbor seal observed in one day, across all survey days (n = 8).
Because harbor seal are uncommon in the area and were only observed
near the Old Jetty, USACE estimated take by Level B harassment to occur
on 7 of the 15 construction days to correspond with the surveys that
are completed closer to the Old Jetty. However, since fine-scale data
regarding harbor seal use in the area are not available, NMFS finds it
more appropriate to estimate that take by Level B harassment might
occur at any of the borehole locations, and USACE agreed. As such, 120
takes by Level B harassment are authorized (8 harbor seal x 15
construction days). No takes by Level A harassment are requested or
authorized given the relative rarity of harbor seal occurrence in
conjunction with planned shutdown requirements.
Steller Sea Lion
The spring-time occurrence of Steller sea lions on St. George
Island near the project area is highly variable across years. Typically
there are no Steller sea lions present on land adjacent to the bay
where the project is to occur in the spring, but occasionally they haul
out at sites across North Rookery (primarily the western end, but
extending east towards the work site), East Reef rookery, and East
Cliffs rookery in groups of up to 100 (Williams 2024, personal
communication). When present, they tend to travel through the project
area and do not linger. During monitoring events conducted on 5 days in
April and June 2024, USACE observed 3 to 14 Steller sea lions traveling
near the western portion of the project area each survey day. USACE
plans to shut down upon observation of Steller sea lions. Given the
plan to shut down, and because Steller sea lions inconsistently occur
in the project area, are conspicuous, and do not tend to linger, no
takes are expected to occur and none are authorized.
Killer Whale
Killer whale have been observed in nearshore habitats of the
Pribilofs including from viewing locations near the project site.
Killer whale are conspicuous and USACE plans to shut down upon
observation of killer whale nearing the Level B harassment zone.
Shutdown zones for killer whale have been established at 300 meters (m)
during borehole drilling and 400 m during LPT, whereas the calculated
Level B harassment zones are 247 m and 293 m, respectively. As such, no
takes by Level B or Level A harassment is requested or authorized.
[[Page 15704]]
Table 8--Take by Stock and Harassment Type and as a Percentage of Stock Abundance
----------------------------------------------------------------------------------------------------------------
Take as
Level A Level B percentage of
Species Stock harassment harassment stock
abundance
----------------------------------------------------------------------------------------------------------------
Harbor Seal........................... Pribilof................ 0 120 \1\52
Northern Fur Seal..................... E. Pacific.............. 35 13,465 2
Steller Sea Lion...................... Western DPS............. 0 0 0
Killer Whale.......................... Eastern North Pacific 0 0 0
Alaska Resident.
Eastern North Pacific 0 0 0
Gulf of Alaska,
Aleutian Islands and
Bering Sea Transient.
----------------------------------------------------------------------------------------------------------------
\1\ These numbers represent the estimated incidents of take, not the number of individuals taken (see Small
Numbers section).
Mitigation
In order to issue an IHA under section 101(a)(5)(D) of the MMPA,
NMFS must set forth the permissible methods of taking pursuant to the
activity, and other means of effecting the least practicable impact on
the species or stock and its habitat, paying particular attention to
rookeries, mating grounds, and areas of similar significance, and on
the availability of the species or stock for taking for certain
subsistence uses. NMFS regulations require applicants for incidental
take authorizations to include information about the availability and
feasibility (economic and technological) of equipment, methods, and
manner of conducting the activity or other means of effecting the least
practicable adverse impact upon the affected species or stocks, and
their habitat (50 CFR 216.104(a)(11)).
In evaluating how mitigation may or may not be appropriate to
ensure the least practicable adverse impact on species or stocks and
their habitat, as well as subsistence uses where applicable, NMFS
considers two primary factors:
(1) The manner in which, and the degree to which, the successful
implementation of the measure(s) is expected to reduce impacts to
marine mammals, marine mammal species or stocks, and their habitat.
This considers the nature of the potential adverse impact being
mitigated (likelihood, scope, range). It further considers the
likelihood that the measure will be effective if implemented
(probability of accomplishing the mitigating result if implemented as
planned), the likelihood of effective implementation (probability
implemented as planned), and;
(2) The practicability of the measures for applicant
implementation, which may consider such things as cost, and impact on
operations.
Mitigation for Marine Mammals and Their Habitat
Temporal Work Restriction--Temporal restrictions in places where
marine mammals are concentrated, engaged in biologically important
behaviors, and/or present in sensitive life stages are effective
measures for reducing the magnitude and severity of human impacts. NMFS
is requiring a temporal work restriction to minimize the consequences
of noise exposure to northern fur seal at North Rookery incidental to
USACE's geotechnical surveys. This temporal work restriction is
expected to greatly reduce the number and severity of northern fur seal
takes that would otherwise occur should activities be conducted after
arrival of pregnant females to the area in mid-June.
Shutdown Zones--For all in-water survey activities, USACE will
implement shutdowns within designated zones. The purpose of a shutdown
zone is generally to define an area within which shutdown of the
activity will 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
9). For harbor seal, the shutdown zones are based on the estimated
Level A harassment isopleth. For northern fur seal, the shutdown zone
for LPT is set at 50 m (slightly less than the estimated Level A
harassment zone of 66 m) to minimize practicability concerns, i.e.,
that increased shutdowns may result in failure to complete the project
in a timely fashion (given that non-breeding male northern fur seal are
common in the project area).
Table 9--Shutdown Zones
----------------------------------------------------------------------------------------------------------------
Shutdown zones (m)
-----------------------------------------------------------------------------
OW
Activity -------------------------
LF HF VHF PW Northern
fur seal Other OW
----------------------------------------------------------------------------------------------------------------
Borehole Drilling................. 300 10 10 300
-----------------------------------------------------------------------------
LPT............................... 400 200 50 400
----------------------------------------------------------------------------------------------------------------
Construction supervisors and crews, Protected Species Observers
(PSOs), and relevant USACE 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 9, or 15 minutes have passed
without re-detection of the animal.
[[Page 15705]]
Finally, construction activities must be halted upon observation of
a species for which incidental take is not authorized or a species for
which incidental take has been authorized but the authorized number of
takes has been met entering or within any harassment zone. If a marine
mammal species not covered under the IHA enters a harassment zone, all
in-water activities will cease until the animal leaves the zone or has
not been observed for at least 15 minutes, and NMFS would be notified
about species and precautions taken. Borehole drilling and LPT will
proceed if the unauthorized species is observed leaving the harassment
zone or if 15 minutes have passed since the last observation.
Protected Species Observers (PSOs)--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 during all in-water LPT and borehole drilling activities. In
such cases, PSOs will monitor the shutdown zone and beyond to the
greatest extent practicable. USACE will employ at least two PSOs for
all geotechnical survey activities.
Monitoring for Level A and Level B Harassment--PSOs will monitor
the shutdown zones and beyond to the extent that PSOs can see.
Monitoring beyond the shutdown zones enables observers to be aware of
and communicate the presence of marine mammals in the project areas
outside the shutdown zones and thus prepare for a potential cessation
of activity should the animal enter the shutdown zone. If a marine
mammal enters either harassment zone, PSOs will document the marine
mammal's presence and behavior.
Pre-and Post-Activity Monitoring--Prior to the start of daily in-
water construction activity, or whenever a break in geotechnical survey
activities of 30 minutes or longer occurs, PSOs will observe the
shutdown zones and as much as the harassment zones as possible for a
period of 30 minutes. Pre-start clearance monitoring must be conducted
during periods of visibility sufficient for the lead PSO to determine
that the shutdown zones are clear of marine mammals. If the shutdown
zone is obscured by fog or poor lighting conditions, in-water
construction activity will not be initiated until the entire shutdown
zone is visible. Geotechnical survey activities 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, geotechnical survey
activity must be delayed or halted. If geotechnical survey activities
are delayed or halted due to the presence of a marine mammal, the
activity may not commence or resume until either the animal has
voluntarily exited and been visually confirmed beyond the shutdown zone
or 15 minutes have passed without re-detection of the animal. If a
marine mammal for which take by Level B harassment is authorized is
present in the Level B harassment zone, activities may begin.
Soft Start--Note that while NMFS typically requires soft starts for
impact pile driving activities, USACE indicated this mitigation measure
is not appropriate for LPT because it is not possible to decrease the
impact from the LPT because the number of blows per fixed distance
driven is an indicator of soil properties that are used in design.
Based on our evaluation of the applicant's planned measures, NMFS
has determined that the mitigation measures provide the means of
effecting the least practicable impact on the affected species or
stocks and their habitat, paying particular attention to rookeries,
mating grounds, and areas of similar significance, and on the
availability of such species or stock for subsistence..
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 during geotechnical
survey activities must be conducted by NMFS-approved PSOs in a manner
consistent with the following:
PSOs must be independent (i.e., not construction
personnel), 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 should 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;
[[Page 15706]]
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 of the Project Area--Visual monitoring of the
project area will be conducted by a minimum of two trained PSOs
positioned at suitable vantage points (see figure 3-2 in the Marine
Mammal Mitigation and Monitoring Plan). During all geotechnical
activities, at least two PSOs will be assigned to each active survey
location to monitor the shutdown zones and harassment zones. At least
one of these PSOs will observe from the cliffs adjacent to the project
site. When conducting geotechnical survey activities at offshore
locations, one of these PSOs will be placed on the barge.
Monitoring of the project area 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 geotechnical survey activities.
Geotechnical survey activities include the time to conduct LPT and
borehole drilling, as long as the time elapsed between uses of the
geotechnical survey equipment is no more than 30 minutes.
Visual Monitoring of North Rookery--To inform take estimates for
future construction activities, PSOs will also conduct daily morning
counts of hauled out pinnipeds at North Rookery, from the Northern
Point of north Rookery and following the rocky shoreline to the south,
during the project period and in the morning, prior to commencing work.
USACE will determine the site specific counting area each day based on
accessibility, any need to avoid seals above the cliffs, and visibility
below the cliffs. USACE will provide coordinates identifying the PSO
monitoring location and the start and end location of where counts are
conducted each day.
Reporting
USACE will submit a draft marine mammal monitoring report to NMFS
within 90 days after the completion of geotechnical survey 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 during all visual monitoring, and associated PSO data sheets.
Specifically, the report will include:
Dates and times (begin and end) of all marine mammal
monitoring;
Geotechnical survey activities occurring during each daily
observation period, including: (1) the number and type of survey
activities completed and the method (e.g., LPT or borehole drilling);
and, (2) total duration of driving time for each survey location
(borehole drilling) and number of strikes for each survey location
(LPT);
PSO locations during marine mammal monitoring;
Start and end location of monitoring area associated with
Visual Monitoring of North Rookery morning counts;
Environmental conditions during monitoring periods (at
beginning and end of PSO shift and whenever conditions change
significantly), including Beaufort sea state and any other relevant
weather conditions including cloud cover, fog, sun glare, and overall
visibility to the horizon, and estimated observable distance;
During all monitoring efforts, 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 survey location 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.);
During monitoring associated with geotechnical activities
only, the following information (1) animal's closest point of approach
and estimated time spent within the harassment zone; and, (2)
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 data
will be submitted electronically in a format that can be queried, such
as a spreadsheet or database, and will be submitted with the draft
marine mammal report.
In the event that personnel involved in the geotechnical 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 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
[[Page 15707]]
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.
Geotechnical surveys associated with the project, as outlined
previously, have the potential to disturb or displace marine mammals.
Specifically, the specified activities may result in take, in the form
of Level B and Level A harassment, from underwater sounds generated by
borehole drilling and LPT. Potential takes could occur if individuals
are present in the ensonified zone when these activities are underway.
Takes by Level B harassment would be due to potential behavioral
disturbance and TTS. Takes by Level A harassment would be due to AUD
INJ. No serious injury or mortality is be expected, even in the absence
of required mitigation measures, given the nature of the activities.
The potential for harassment will be further minimized through the
implementation of planned mitigation measures (see Mitigation section).
A low amount of take by Level A harassment is expected for northern fur
seal (n=35) to account for the possibility that an animal would enter
the Level A harassment zone and remain within that zone for a duration
long enough to incur AUD INJ before moving away. Any take by Level A
harassment of northern fur seal 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 LPT such as the low-frequency region below 2 kHz), not
severe hearing impairment or impairment within the ranges of greatest
hearing sensitivity. Animals would need to be exposed to higher levels
and/or longer duration than are expected to occur here in order to
incur any more than a small degree of PTS. Some subset of northern fur
seal or harbor seal 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. Likewise, due
to the small degree anticipated, any PTS potential 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.
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 geotechnical surveys are 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 geotechnical surveys would not be
permanently displaced. Indirect effects on marine mammal prey during
the geotechnical surveys are expected to be minor, and these effects
are unlikely to cause substantial effects on marine mammals at the
individual level. Given the time of year in which project activities
are planned, 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.
For harbor seal, take would occur within a limited, relatively
confined area of the stock's range, which is not of particular
importance for harbor seal that may occur there. Given the availability
of suitable habitat nearby, any displacement of marine mammals from the
project areas is not expected to affect marine mammals' fitness,
survival, and reproduction due to the limited geographic area that
would be affected in comparison to available habitat elsewhere on the
island. Additionally, NMFS anticipates that the prescribed mitigation
will minimize the duration and intensity of expected harassment events.
While the project site is located adjacent to the largest northern
fur seal rookery in the world, the exposure of northern fur seal to
sound from the planned activities would be minimized by the time of
year the work is planned and required mitigation measures (e.g.,
shutdown zones). Beginning in April, adult males will land at a number
of sites where they begin to determine which site to establish their
breeding territory before the arrival of females in mid-June and July.
Non-breeding aged males will land and haul out along the rocky
shoreline adjacent to the Access Ramp labeled in figure 4-3 in the
USACE's application, while, territorial males will occupy and defend
prime breeding territories before females arrive in mid-June and July.
Pregnant females arrive around mid-June each year. They give birth just
days after arrival on land and then mate (NMFS, 2024). Pups are nursed
until weaning (about 4 months) and leave their breeding site before
their mothers to forage independently for the first time.
[[Page 15708]]
All in-water geotechnical survey activities will be conducted
between April 15 and June 15. The planned temporal work restriction is
established to ensure that project activities do not impact northern
fur seals during sensitive life stages (i.e., when pregnant and pupping
northern fur seals are present). The temporal work restriction would
also greatly reduce the overall number of takes of northern fur seal as
fewer northern fur seal are present in the spring compared to the
summer.
While the project site is adjacent to the largest northern fur seal
rookery in the world, the effects of the activities on marine mammal
habitat generally, such as sedimentation and impacts to the
availability of prey species, are expected to be limited both spatially
and temporally, constrained to the immediate area around each
geotechnical survey location and returning to baseline levels quickly.
Some fish may leave the area of disturbance, thus temporarily impacting
foraging opportunities for non-breeding male northern fur seals
(territorial males do not forage after establishing territories) and
harbor seal in a limited portion of the foraging range; but, because of
the short duration of the activities and the relatively small area of
the habitat that may be affected, the impacts to marine mammal habitat
are not expected to cause significant or long-term negative
consequences.
In addition, it is unlikely that minor noise effects in a small,
localized area of habitat would have any effect on each stock's ability
to recover. In combination, we believe that these factors, as well as
the available body of evidence from other similar activities,
demonstrate that the potential effects of the specified activities
would have only minor, short-term effects on individuals. The specified
activities are not expected to impact rates of recruitment or survival
and would therefore not result in population-level impacts.
In summary and as described above, the following factors primarily
support our 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;
Level A harassment, for northern fur seal only, would be
very small amounts of a low degree;
Anticipated take by Level B harassment are relatively low
for all stocks;
Level B harassment would be primarily in the form of
behavioral disturbance, resulting in avoidance of the project areas
around where borehole drilling or LPT is occurring, with some low-level
TTS that may limit the detection of acoustic cues for relatively brief
amounts of time in relatively confined footprints of activities;
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 ensonified areas are very small relative to the
overall habitat ranges of all species and stocks, and would not
adversely affect any areas of known biological importance;
The lack of anticipated significant or long-term negative
effects to marine mammal habitat; and,
USACE will implement mitigation measures including visual
monitoring, and shutdown zones to minimize the numbers of marine
mammals exposed to injurious levels of sound.
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 required 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
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 amount of take NMFS authorized is below one-third of the
estimated stock abundance for all species, except for Pribilof Island
harbor seals (table 1).
The total number of takes authorized of harbor seal, if assumed to
accrue solely to new individuals of the Pribilof Island stock, is >50
percent of the total stock abundance, which is currently estimated as
229. However, these numbers represent the estimated incidents of take,
not the number of individuals taken. That is, it is expected that a
relatively small subset of these harbor seal would be harassed by
project activities, as harbor seal primarily occur to the west on the
far side of St. George Island. (Williams, 2024, personal
communication). Given that the specified activity will be stationary
within an area not recognized as any special significance that would
serve to attract or aggregate harbor seals we therefore believe that
the estimated numbers of takes, were they to occur, likely represent
repeated exposures of a much smaller number of harbor seals and that
these estimated incidents of take represent small numbers of harbor
seal.
Based on the analysis contained herein of the planned activity
(including the 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.
Alaska Natives on St. George Island harvest subsistence resources,
including northern fur seal, harbor seal, and Steller sea lion.
Pribilovians on St. George Island may harvest up to a total of 500 male
fur seals each year over the course of both the sub-adult harvest and
the male young of the year harvest (50 CFR 216.72), On St. George
Island, the open season for male sub-adult fur seal
[[Page 15709]]
harvest runs from June 23 through August 8 annually, while the male
young of the year fur seal open season spans from September 16 through
November 30 annually. The most recent monitoring report available
indicates that only 10 male sub-adult fur seal and 6 male young of the
year fur seal were harvested in 2023 (Kashevarof, 2023a; Kashevarof,
2023b). There are no formal seasons for harbor seals or Steller sea
lion, but historically they are spring, winter, and fall (Williams,
2025, personal communication).
USACE contacted Mark Merculief, the mayor St. George, Alaska, and
described him as a subsistence hunter who personally knows every
subsistence hunter in St. George community. Mayor Merculief indicated
that in recent years there have been no subsistence efforts for marine
mammals during the planned project period.
The project is not likely to adversely impact the availability of
any marine mammal species or stocks that are commonly used for
subsistence purposes or impact subsistence harvest of marine mammals in
the region because:
Geotechnical surveys are planned to be conducted prior to
the opening of subsistence hunting for northern fur seal and during a
time when other pinnipeds have not been subsistence harvested in recent
years;
Geotechnical surveys are temporary and localized to
between the Old Jetty and North Rookery;
Mitigation measures will be implemented to avoid
disturbance of Steller sea lion in the area and minimize disturbance of
harbor seal and northern fur seal;
The project is not expected to result in significant
changes to availability of subsistence resources.
Based on the description of the specified activity, the measures
described to minimize adverse effects on the availability of marine
mammals for subsistence purposes, and the mitigation and monitoring
measures, NMFS has determined that there will not be an unmitigable
adverse impact on subsistence uses from USACE's activities.
Endangered Species Act
Section 7(a)(2) of the ESA of 1973 (16 U.S.C. 1531 et seq.)
requires that each Federal agency 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.
No incidental take of ESA-listed species is authorized or expected
to result from this activity. Therefore, NMFS has determined that
formal consultation under section 7 of the ESA is not required for this
action.
National Environmental Policy Act
To comply with the National Environmental Policy Act of 1969 (NEPA;
42 U.S.C. 4321 et seq.) and NOAA Administrative Order (NAO) 216-6A,
NMFS must review our proposed action (i.e., the issuance of an IHA)
with respect to potential impacts on the human environment.
This action is consistent with categories of activities identified
in Categorical Exclusion B4 (IHAs with no anticipated serious injury or
mortality) of the Companion Manual for NAO 216-6A, which do not
individually or cumulatively have the potential for significant impacts
on the quality of the human environment and for which we have not
identified any extraordinary circumstances that would preclude this
categorical exclusion. Accordingly, NMFS has determined that the
issuance of this IHA qualifies to be categorically excluded from
further NEPA review.
Authorization
NMFS has issued an IHA to USACE for the potential harassment of
small numbers of two marine mammal species incidental to the
geotechnical survey activities in St. George, Alaska, that includes the
previously explained mitigation, monitoring and reporting requirements.
Dated: April 10, 2025.
Kimberly Damon-Randall,
Director, Office of Protected Resources, National Marine Fisheries
Service.
[FR Doc. 2025-06376 Filed 4-14-25; 8:45 am]
BILLING CODE 3510-22-P