Notice2025-15863
Takes of Marine Mammals Incidental to Specified Activities; Taking Marine Mammals Incidental to Narwhal, LLC Oil and Gas Exploration Activities in West Harrison Bay, Alaska
Primary source
Metadata and text below are from the Federal Register, a public-domain U.S. government work. Always verify the official published version before relying on it for any legal matter.
Published
August 20, 2025
Issuing agencies
Commerce DepartmentNational Oceanic and Atmospheric Administration
Abstract
Notification is hereby given that NMFS has issued an incidental harassment authorization (IHA) to Narwhal, LLC (Narwhal) to incidentally take by harassment marine mammals during oil and gas exploration activities in west Harrison Bay, Alaska.
Full Text
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<title>Federal Register, Volume 90 Issue 159 (Wednesday, August 20, 2025)</title>
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[Federal Register Volume 90, Number 159 (Wednesday, August 20, 2025)]
[Notices]
[Pages 40568-40591]
From the Federal Register Online via the Government Publishing Office [<a href="http://www.gpo.gov">www.gpo.gov</a>]
[FR Doc No: 2025-15863]
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DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
[RTID 0648-XE957]
Takes of Marine Mammals Incidental to Specified Activities;
Taking Marine Mammals Incidental to Narwhal, LLC Oil and Gas
Exploration Activities in West Harrison Bay, 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: Notification is hereby given that NMFS has issued an
incidental harassment authorization (IHA) to Narwhal, LLC (Narwhal) to
incidentally take by harassment marine mammals during oil and gas
exploration activities in west Harrison Bay, Alaska.
DATES: This authorization is effective for one year from the date of
notification by the IHA-holder, not to exceed one year from the date of
issuance (August 12, 2025).
ADDRESSES: Electronic copies of the application, IHA, and supporting
documents, as well as a list of the references cited in this document,
may be obtained online at: <a href="https://www.fisheries.noaa.gov/action/incidental-take-authorization-narwhal-llcs-oil-and-gas-exploration-activities-west-harrison">https://www.fisheries.noaa.gov/action/incidental-take-authorization-narwhal-llcs-oil-and-gas-exploration-activities-west-harrison</a>. In case of problems accessing these
documents, please contact the contact listed below.
FOR FURTHER INFORMATION CONTACT: Craig Cockrell, Office of Protected
Resources, NMFS, (301) 427-8401.
SUPPLEMENTARY INFORMATION:
Background
The MMPA prohibits the ``take'' of marine mammals, with certain
exceptions. Section 101(a)(5)(A) and (D) of the MMPA (16 U.S.C. 1361 et
seq.) directs the Secretary of Commerce (as delegated to NMFS) to
allow, upon request, the incidental, but not intentional, taking of
small numbers of marine mammals by U.S. citizens who engage in a
specified activity (other than commercial fishing) within a specified
geographical region if certain findings are made and either regulations
are proposed or, if the taking is limited to harassment, a notice of a
proposed IHA is provided to the public for review.
Authorization for incidental takings shall be granted if NMFS finds
that the taking will have a negligible impact on the species or
stock(s) and will not have an unmitigable adverse impact on the
availability of the species or stock(s) for taking for subsistence uses
(where relevant). Further, NMFS must prescribe the permissible methods
of taking and other ``means of effecting the least practicable adverse
impact'' on the affected species or stocks and their habitat, paying
particular attention to rookeries, mating grounds, and areas of similar
significance, and on the availability of the species or stocks for
taking for certain subsistence uses (referred to in shorthand as
``mitigation''); and requirements pertaining to the mitigation,
monitoring and reporting of the takings are set forth. The definitions
of all applicable MMPA statutory terms cited above are included in the
relevant sections below.
Summary of Request
On October 25, 2022, NMFS received a request from Narwhal for an
IHA to take marine mammals incidental to oil and gas exploration
activities in and around west Harrison Bay, Alaska. Narwhal withdrew
the original request and then resubmitted an application on November 1,
2024. The application was deemed adequate and complete on January 27,
2025. Narwhal's request is for take of four marine mammal species, by
Level B harassment only. Neither Narwhal nor NMFS expect serious injury
or mortality to result from the specified activity, and therefore, an
IHA is appropriate.
Description of Activity
Overview
Narwhal proposes to conduct oil and gas exploration activities,
including shallow hazard geophysical surveys, exploratory drilling
operations, and associated construction and operation of ice trails,
roads, and pads, in west Harrison Bay, Alaska. The activities are
planned to occur between August 2025 and July 2026 and will occur
primarily in west Harrison Bay and the area between west Harrison Bay
and Prudhoe Bay, Alaska. Narwhal will also conduct mobilization and
barge transport activities out of Prudhoe Bay, Alaska. Shallow hazard
geophysical surveys (hereinafter, ``shallow water hazard surveys'')
will use airguns and sparkers as acoustic sources and would introduce
underwater sound that may result in
[[Page 40569]]
take by Level B harassment of marine mammals. Construction and
operation of sea ice trails around the Colville River Delta may result
in take by Level B harassment of ringed seals due visual disturbance.
Shallow hazard surveys at all six sites will take place over
approximately 12 days and will occur over a 12-hour period each day.
Offshore ice road and trail construction will occur over approximately
167 days and will occur as needed throughout a 24-hour period. A number
of other activities will occur during the course of the specified
activities, but, they are not expected to result in take of marine
mammals.
Since publication of the Federal Register notice of the proposed
IHA, Narwhal estimates that eight barges may need to be used for option
staging activities (see 90 FR 21182, 21185, May 16, 2025). This minor
change to this activity does not change NMFS' determination that this
activity is unlikely to result in take of marine mammals.
A detailed description of the specified activities is provided in
the Federal Register notice for the proposed IHA (90 FR 21182, May 16,
2025). No other 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 specified
activity.
Comments and Responses
A notice of NMFS' proposal to issue an IHA to Narwhal was published
in the Federal Register on May 16, 2025 (90 FR 21182). That notice
described, in detail, Narwhal's specified activities, 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. NMFS received one substantive comment letter
from the Center for Biological Diversity (CBD). Please see CBD's
comment letter, available online at <a href="https://www.fisheries.noaa.gov/action/incidental-take-authorization-narwhal-llcs-oil-and-gas-exploration-activities-west-harrison">https://www.fisheries.noaa.gov/action/incidental-take-authorization-narwhal-llcs-oil-and-gas-exploration-activities-west-harrison</a>, for full detail regarding the
comments and associated rationale. The Arctic Peer Review Panel (PRP),
convened by NMFS as required under 50 CFR 216.108(d), reviewed the
Monitoring Plan (please see the Monitoring Plan Peer Review section,
below). We have not responded to comments that failed to raise a
significant point for us to consider (e.g., comments that are out of
scope of the proposed IHA; mitigation, monitoring, or reporting
measures already included in the proposed IHA). Furthermore, if a
comment received was unclear, NMFS does not include it here as it could
not determine whether it raised a significant point for NMFS to
consider.
Comment 1: The PRP stated that NMFS should require aircraft used by
Narwhal to follow flight paths either five miles inland or five miles
offshore to minimize impacts to subsistence hunting for marine mammals.
Response 1: NMFS disagrees with this recommended mitigation
measure. The IHA contains a minimum altitude limit for aircraft to
avoid potential disturbance to marine mammals or effects to the
availability of marine mammals for subsistence uses. All aircraft must
maintain an altitude of 457 meters (m) (1,500 feet (ft)) during flight
and if flights must occur below 457 m the flight course must be altered
to maintain 457 m of horizontal separation from any marine mammals. The
recommended measure is impracticable given the unpredictability of
weather conditions and the remote nature of the project area; pilots
will fly the most direct path to the aerial survey areas to minimize
time in the air but maintain the minimum altitude requirements. Given
the low potential for take from this activity and the mitigation
measure of 457 m minimum altitude for aircraft, based on the best
available scientific information, the likelihood of take by Level B
harassment from this activity is discountable.
Comment 2: CBD asserted that NMFS did not provide adequate
justification to assume that aircraft flights flown at a minimum of 457
m by Narwhal would not result in take of marine mammals and NMFS'
determination that no take would result from this activity is
inaccurate.
Response 2: NMFS disagrees that flights operated at a minimum
altitude of 457 m would result in takes of marine mammals. In Narwhal's
application, they note that received levels of in-air noise from fixed-
wing propeller aircraft sounds ranged from 75 to 90 dB and airborne
noise levels from helicopters were 60 to 70 dB at 460 m (1509 ft.)
(Richardson et al. 1995). This is below the 100 dB disturbance
threshold for in-air sounds for pinnipeds (NMFS 2024). To affect the
least practicable adverse impact on and marine mammals and based on
Born et al. (1999), which indicated that if the aircraft does not
approach the seals closer than an altitude of 500 m (1,640 ft), the
risk of flushing the seals into the water can be greatly reduced. Based
on the analysis presented above and in the proposed IHA, NMFS proposed
the minimum altitude of 457 m mitigation measure.
CBD partially quotes the Notice of the proposed IHA's summary of
Bradford (2005) (i.e., ``[H]elicopter presence resulted in flushing of
most of the hauled out seals during observations . . .'') to support
their claim that the mitigation measure is insufficient to mitigate
take--the remainder of the sentence in the Notice states, ``. . .
[T]hey did not note specific distances of the helicopter at which
flushing occurred.'' CBD did not provide additional scientific
information for NMFS to consider. Given the low potential for take from
this activity and the mitigation measure of 457 m minimum altitude for
aircraft, based on the best available scientific information, the
likelihood of take by Level B harassment from this activity is
discountable.
Comment 3: The PRP recommended that Narwhal complete its shallow
water hazard survey by August 25th to prevent any diversion of
migrating bowhead whales that may impact the subsistence bowhead hunt
by Kaktovik, Nuiqsut, and Barrow whaling crews.
Response 3: NMFS disagrees that a time restriction measure is
necessary to ensure no unmitigable adverse impact on the availability
of the stock for taking for subsistence uses. The Level B harassment
zone for survey activities is outside the core migration area of
bowhead whales and presence of bowhead whales in west Harrison Bay is
relatively low as reflected in the estimated take analysis. Narwhal has
signed a Conflict Avoidance Agreement (CAA) for this action with
potentially affected communities and will follow the measures included
in the CAA. The Alaska Eskimo Whaling Commission (AEWC) facilitates an
annual CAA that allows for direct communication between subsistence
hunters and industry representatives. The CAA process provides an
important forum for subsistence hunters to share concerns about
potential impacts of proposed projects with industry representatives in
order to inform project implementation, including mitigation measures
intended to avoid impacts to subsistence hunting activities. While not
required, NMFS strongly encourages applicants to engage with AEWC
through the CAA process.
Comment 4: The PRP recommended that staging of equipment for
activities be completed as early as possible to reduce vessel traffic
during the fall migration and hunt.
[[Page 40570]]
Response 4: NMFS disagrees that a time restriction measure is
necessary to ensure no unmitigable adverse impact on the availability
of the stock for taking for subsistence uses because NMFS does not
anticipate take of bowhead whales from this activity. As described in
response to the previous comment, Narwhal recognizes that it must
resolve subsistence concerns raised by potentially affected
communities, and signed a CAA with those communities. Narwhal has
agreed to complete staging activities at the earliest possible date, as
soon as the preferred staging area has been identified and equipment is
available for transport to the staging area.
Comment 5: CBD asserted that NMFS did not adequately analyze the
potential impacts of Narwhal's activities on marine mammals and that
NMFS analysis does not capture the impacts of acoustic disturbances
underestimating potential takes. Specifically, the commenter stated
that spotted seals and ringed seals haul out in response to vessel and
aircraft noise and that bowhead whales exhibit avoidance behaviors and
changes to vocal behaviors at received levels below 160 decibels (dB)
re 1 micropascal ([mu]Pa) when exposed to sound from airguns.
Response 5: NMFS disagrees with CBD's comment and finds that CBD
does not provide compelling rationale for its assertion that NMFS
underestimates takes that are likely to occur. Use of the seismic
airgun and sparker are expected to result in Level B harassment of
marine mammals, as described by NMFS in the proposed IHA notice, which
may include takes primarily resulting from behavioral disturbance or,
as a less likely outcome, temporary threshold shift. Avoidance of
sufficiently aversive stimuli, including noise from Narwhal's seismic
survey activity, is expected to be the main response from bowhead
whales and pinnipeds. For bowhead whales, NMFS agrees that there are
multiple studies documenting changes in behavior and/or communication
amongst large whales in response to airgun noise. Changes in
vocalization associated with exposure to airgun surveys within
migratory and non-migratory contexts have been observed, and NMFS
specifically discussed the results cited by CBD (e.g., Blackwell et
al., 2013) in its notice of proposed IHA. The potential for
anthropogenic sound to have impacts over large spatial scales is not
surprising for species with large communication spaces, like
mysticetes; however, not every change in a vocalization would
necessarily rise to the level of a take. As noted previously, the
planned survey effort would be relatively brief in duration and it is
expected that the shallow waters (e.g., <3 m) where the survey will
occur will have a relatively low density of bowhead whales and would
not result in any sustained impacts to such behaviors for bowhead
whales. CBD did not provide additional scientific information for NMFS
to consider.
Pinnipeds may occur in higher relative abundance compared to
bowhead whales in west Harrison Bay. Although there is likely higher
occurrence of pinnipeds, the use of west Harrison Bay is mainly
transitory and does not include any of the critical habitat for both
bearded and ringed seals. NMFS used the best available scientific
information when determining the appropriate densities of pinnipeds in
the project area and associated take numbers by Level B harassment.
NMFS also considered all of the activities proposed by Narwhal in this
project and made determinations on which activities may result in take.
CBD specifically cites that aircraft noise and vessel noise could cause
seals to haulout. NMFS disagrees with this claim given the mitigation
measures for both aircraft and vessels. Aircraft noise is not
anticipated to result in take given the minimum altitude mitigation
measure as discussed in response to Comment 2, and vessel noise will
not result in take of marine mammals given the size of vessels proposed
for use (<20 ft. (6 m)) and the relatively slow speed of travel.
Therefore, take is neither expected nor authorized.
CBD also fails to provide any additional scientific information for
NMFS to consider regarding Narwhal's project to reasonably assume take
may occur for those activities where NMFS did not authorize take.
Comment 6: CBD states the mitigation measure to complete
construction no later than March 1st to deter pregnant seals from
establishing birth lairs in disturbed areas should be considered as an
additional source of harassment, rather than an effective mitigation
measure and suggests that this is an additional reason why NMFS has
underestimated take.
Response 6: CBD mischaracterizes the construction schedule as a
mitigation measure. NMFS did not propose a mitigation measure requiring
Narwhal to complete construction prior to March 1st. Rather, NMFS
proposed additional mitigation measures after March 1st recognizing
ringed seal birth lair establishment in the project area. NMFS
disagrees incidental take from ice trail activities is underestimated.
In the Notice of the proposed IHA and herein, NMFS estimated the
incidental take of ring seals from the ice trail activities, including
construction, operation, and demobilization, and the estimated take
analysis does not account for mitigation measures associated with these
activities in the analysis. CBD states that ``Disturbing [establishment
of lairs for pupping] can lead to lair abandonment, increased pup
mortality, and exposure to predators and environmental stressors.''
However, as NMFS described in the notice of proposed IHA, the
successful implementation of this requirement would accomplish
avoidance of these outcomes precisely because lairs would not be
established in areas where disturbance is likely to cause abandonment
and/or lead to negative outcomes for pregnant females or pups.
Comment 7: CBD noted that NMFS developed its pinniped take
estimates through use of uniform densities within the project area.
Specifically, density estimates for bearded and spotted seals are
derived from Beaufort Sea vessel-based surveys that are not specific to
Harrison Bay. The estimated density of ringed seals was based on spring
aerial surveys covering a broad area that was not specifically limited
to Harrison Bay. CBD asserts that use of this density data
underestimates or incorrectly estimates take.
Response 7: NMFS acknowledges that data used to determine pinniped
densities included some areas that occur outside the boundaries of west
Harrison Bay. Available data for pinniped densities is limited from
within west Harrison Bay. NMFS used the best scientific information
available to determine the appropriate densities for all of the
pinniped species in the specified geographic region. See the Estimated
of Marine Mammals section for a detailed description of the data
sources that were used to develop the pinniped density estimates. CBD
does not provide additional scientific information for NMFS to
consider.
Comment 8: CBD stated that NMFS' presumption of perfect
implementation of mitigation measures and environmental conditions
introduces significant uncertainty into the estimated take analysis,
particularly related to Level A take. CBD also stated that NMFS failed
to account for animal behaviors ``such as diving and undemonstrative
presence at the sea surface''.
Response 8: NMFS disagrees the estimated take analysis is flawed
due to presumptions regarding the effectiveness of mitigation measures.
As discussed in the Notice of the proposed IHA and herein, the activity
(shallow
[[Page 40571]]
water hazard survey) results in a relatively small ensonified area.
Given the mobile nature of the acoustic sources and because marine
mammals are likely moving through the project areas and not remaining
for extended periods of time, the potential for permanent or temporary
threshold shifts in marine mammal hearing is unlikely. The expected low
density of animals within the project area further reduces the
potential that animals will be present in the Level A harassment zones.
The suite of mitigation measures further reduces the low likelihood
of take. The Level A shutdown zones associated with the operation of
the airgun and sparker are all under 1,100 m (3,281 ft) (see
Mitigation). The relatively small shutdown zones and expected high
detection capability within those zones (for example, approximately
nearly 24 hours of daylight are expected during the planned survey
window) and general avoidance behaviors for marine mammals further
support the conclusion that Level A harassment is not likely. Ramp-up
of the acoustic sources is also expected to produce noise that is
sufficient to warn marine mammals of pending operations and allow
sufficient time for those animals to leave the immediate vicinity. If a
marine mammal appears in the Level A shutdown zone, the acoustic source
will be shut down immediately. These measures would occur prior to
accumulating energy to the extent necessary to cause auditory injury.
While diving behavior has been observed for bowhead whales, that
particular behavior is not expected within the project area given the
shallow waters (i.e., <3 m) and not expected to affect the visual
detection of this species. For these reasons, the likelihood of take by
Level A harassment from this activity is discountable.
Comment 9: CBD asserts that NMFS failed to properly estimate take
because it did not account for the ``cumulative auditory impact'' from
construction, support activity, snow machines, aircrafts, trucks, and
other industrial noise.
Response 9: NMFS disagrees that the analysis in the proposed IHA
and herein fails to account for the impacts of noise. NMFS has
responded in detail about the effects of aircraft in response to
Comment 1. Ice road and trail construction is expected to result in
take by Level B harassment due to the physical presence of construction
equipment and personnel. Both in-air and in-water noise levels are
expected to be below the relevant harassment thresholds. Further,
Williams et al. (2006) found that active ringed seal structures (dens
and breathing holes) experienced notably weaker sound levels due to the
sound being attenuated in the ice and snow. During the winter of 2000,
background unweighted in air noise levels from various machineries
measured in the vicinity of Northstar ranged from 59 to 84 dB re 20
[mu]Pa, and this background noise level was related to wind speed
(Greene et al. 2008). Similar levels were reported during the winter of
2001 and 2002 by Blackwell et al. (2004a, b) with minimum background
unweighted in-air noise levels of 44 to 52 dB re 20 [mu]Pa measured in
ice-covered conditions with low wind up to 10 km (6 mi) from Northstar
in Prudhoe Bay. Therefore, in-air and in-water acoustic impacts of the
ice trail construction are not expected for ringed seals.
Further, acoustic impacts associated with the drilling activities
are similarly not expected to exceed the relevant harassment criteria.
As described in the proposed IHA (May 16, 2025, 90 FR 21182) drilling
sounds are expected to transmit poorly from the drill rig machinery
through ice or soft substrate into the water (Richardson et al. 1995).
Underwater sound during drilling alone (i.e., without other production
noises from the island) were reported in Blackwell et al. (2004a) as
114 dB re 1[mu]Pa at 250 m (820 ft) from the source during ice-covered
conditions. The lowest level of underwater sound recorded during
drilling alone was reported as 104 dB re 1[mu]Pa at 1 km, while
background sound levels (measured at 95 dB re 1[mu]Pa) were reached 2
to 4 km from the source (Blackwell et al. 2004a). Given the low level
of sound expected to be produced by the drilling activities, take of
marine mammals is not likely to occur from this activity.
CBD does not provide any additional information for NMFS to
consider regarding the auditory impacts of sound within the project
area. Moreover, these activities will generally occur at different
times and locations and thus, NMFS does not anticipate cumulative
acoustic impacts from these activities on marine mammals.
Comment 10: CBD states NMFS' estimate take analysis fails to
account for cumulative stress from climate change on ice seals and how
such stress can make ice seals more vulnerable to project activities,
including auditory and physical impact from ice road and trail
construction.
Response 10: NMFS is required to authorize the requested incidental
take by harassment if it finds the incidental take of small numbers of
marine mammals by U.S. citizens ``while engaging in that (specified)
activity'' within a specified geographic region will have a negligible
impact on such species or stock and, where applicable, will not have an
unmitigable adverse impact on the availability of such species or stock
for subsistence uses (16 U.S.C. 1371(a)(5)(D)). The relevant specified
activities here are ice trail construction and operation. Therefore,
NMFS' estimated take analysis was appropriately limited to incidental
take from ice trail construction and operation.
NMFS agrees that decreases in ice cover could negatively affect ice
seals in the future and consistent with the preamble of NMFS'
implementing regulations, NMFS considered the effects of climate in the
affected environment analysis of the final EA for this action and
Biological Opinion issued pursuant to Section 7 of the ESA (54 FR
40338, September 29, 1989).
Comment 11: CBD asserted that NMFS proposed mitigation measures
failed to ensure the least practicable adverse impact on affected
marine mammals and claims that NMFS' negligible impact determination
for all species depends on the successful implementation of mitigation
measures. Specifically, CBD noted that detection-based mitigation
measures, such as implementation of shutdown zones, rely on the ability
of marine mammal observers to detect marine mammals and are not as
effective as time/area restrictions. CBD states that NMFS does not
adequately acknowledge the limitations of observers. Further, CBD
claims that the ramp-up procedures NMFS has proposed may not be an
effective deterrent to acoustic sources. CBD finally states that its
claims support ``the need for more robust pre-activity monitoring and
supplementary mitigation strategies which are of greater known
effectiveness.''
Response 11: NMFS disagrees with the commenter that the proposed
mitigation measures do not meet the least practicable adverse impact
determination. The use of time/area restrictions is not practicable for
this project since the presence of marine mammals, while low in overall
density, could be present throughout the year.
The use of PSOs and ramp-up procedures are a standard practice in
seismic surveys and have been well documented in minimizing the number
and/or severity of incidents of take of animals. The use of shutdowns
initiated by PSOs have been documented in monitoring reports for
seismic surveys.
[[Page 40572]]
During three years of observation in the Gulf of America oil and gas
exploration activities, 106 shutdowns of active sources occurred when
marine mammals were spotted in established shutdown zones. During pre-
activity monitoring, 155 delays occurred when marine mammals were
spotted in either the shutdown zones or Level B harassment zones
(EnerGeo Alliance 2025). Given the high avoidance rates of marine
mammals authorized in response to seismic airguns as discussed in
response to Comment 5, NMFS expects that the use of ramp-up procedures
would be effective at warning marine mammals and providing sufficient
time for those animals to leave the immediate vicinity. CBD fails to
recommend measures that would increase the effectiveness of pre-
activity monitoring.
While the negligible impact determination takes into consideration
the implementation of mitigation and monitoring measures, it is not
dependent on successful implementation of such measures (see Negligible
Impact Analysis and Determination section).
Comment 12: CBD noted that NMFS should have required additional
mitigation measures, including the use of passive acoustic monitoring
(PAM) to detect marine mammals ahead of approaching active acoustic
sources, the use of a bubble curtain to attenuate the sound from the
seismic airgun, and the use of drones for visual monitoring of shutdown
and harassment zones.
Response 12: NMFS has determined requiring PAM for this project
does not affect the least practicable adverse impact on marine mammals.
It is not practicable for Narwhal because berthing space on the vessels
used for the shallow water hazard survey is extremely limited and
additional vessels would need to be used to accommodate the additional
PAM equipment. Furthermore, NMFS has determined PAM is not likely to be
particularly useful for these survey activities, nor is it necessary
for low-energy surveys with the relatively small harassment zones
considered here. With specific regard to bowhead whales, it is
generally well-accepted fact that, even in the absence of a firing
airgun, using a towed passive acoustic sensor to detect baleen whales
(including bowhead whales) is not typically effective because the noise
from the vessel, the flow noise, and the cable noise are in the same
frequency band and will mask the vast majority of baleen whale calls.
Because the seismic pulse and the whale's call are within the same
frequency range, and the seismic pulse is much louder than the whale's
call (see below), it is unlikely that a baleen whale can be detected
during the seismic pulse, therefore PAM becomes ineffective at
detecting approaching whales.
NMFS has determined the use of bubble curtains for noise
attenuation during survey activities does not affect the least
practicable adverse impact on marine mammals. Typically, use of bubble
curtains occurs during the use of impulsive acoustic sources on
stationary objects and attenuates the sound produced from the source.
The use of bubble curtains on a mobile source would be difficult to
execute and may not prove effective at attenuating the noise produced
during the shallow water hazard survey. CBD did not provide additional
information for NMFS to consider to support the effectiveness of its
proposed mitigation measure, particularly during a mobile survey.
NMFS agrees with the commenter that drones can be an effective tool
for monitoring for marine mammals during certain projects. As stated in
the response for Comment 13, NMFS believed that visual monitoring and
the related protocols NMFS has prescribed are an appropriate part of
the suite of mitigation measures here that satisfy the MMPA's least
practicable adverse impact standard. Additionally, it is expected that
there will be nearly 24 hours of daylight during the shallow water
hazard survey and low-light conditions should not persist during
monitoring periods. The use of drones would not substantially increase
the effectiveness of the mitigation measures or affect the least
practicable adverse impact determination. The use of drones are also
not practicable for Narwhal to implement due the need for FAA licensed
and trained staff on vessels, limited deck space for staff and the
drones, and the distance limitations of some drones would render them
unusable for observing for long periods. Further, CBD provides no
evidence that drones can fully replace visual monitoring as an
effective monitoring measure for this mobile survey.
Comment 13: CBD stated that the current 15-minute pre-activity
monitoring and 15-minute post shutdown monitoring period are
insufficient for the clearance of shutdown zones. CBD urged NMFS to
consider a 30-minute period for bowhead whales citing deep diving
behavior and drift diving behavior which may cause them to linger in an
area for prolonged periods.
Response 13: NMFS disagrees extending the monitoring periods will
affect the least practicable adverse impact on marine mammals. The
survey will generally occur in waters 3 meters or less. If bowhead
whales are present in the area, it is expected that they will
continuously move through the area, and their movements will be
observed by PSOs. Diving behavior of bowhead whales is not expected to
occur in the project area due to the shallow water. Additionally given
the tight turns and quick succession of track lines of the seismic
survey design which minimize the down time of the acoustic sources, 15-
minute pre-clearance periods would be sufficient to monitor the area
before beginning a new track line.
Comment 14: CBD stated that NMFS cannot issue ``Renewed'' IHAs
under the MMPA. Further, CBD stated that NMFS cannot issue
``successive'' IHAs without a comprehensive analysis and must analyze
and mitigate the total take it is proposing to authorize across all two
years. Additionally, CBD stated that the 15-day comment period proposed
for renewals is also unlawful and places a burden on interested members
of the public to review not only the original authorization and
supporting documents but also the draft monitoring reports, the renewal
request, and the proposed renewed authorization and then to formulate
comments, all within 15 calendar days. They assert that NMFS should set
forth, via proposed regulation or policy document, its rationale for
the renewal process and to allow public comment.
Response 14: The process of issuing a Renewal IHA does not bypass
the public notice and comment requirements of the MMPA. The notice of
the proposed IHA initiated a 30-day public comment period and expressly
notifies the public that under certain, limited conditions an applicant
could seek a Renewal IHA for an additional year. The notice describes
the conditions under which such a renewal request could be considered
and expressly seeks public comment in the event such a renewal is
sought. Importantly, any such renewals (if issued) would be limited to
where the activities are identical or nearly identical to those
analyzed in the proposed IHA, monitoring does not indicate impacts that
were not previously analyzed and authorized, and the mitigation and
monitoring requirements remain the same, all of which allow the public
to comment on the appropriateness and effects of a renewal at the same
time the public provides comments on the initial IHA.
Importantly, Renewal IHAs are evaluated by NMFS on a case-by-case
basis and are not an automatic matter of right. Each 1-year IHA must
independently satisfy the negligible
[[Page 40573]]
impact standard for the authorized taking and include the means of
effecting the least practicable adverse impact on the species or stock
and its habitat and, where relevant, on the availability of such
species or stock for taking for subsistence uses (i.e., mitigation).
Moreover, NMFS is not proposing to issue a ``successive'' IHA for a
second year. For these reasons, a comprehensive analysis of the impacts
of potential take across 2 years is not appropriate under the MMPA. Any
renewal request would be evaluated under the appropriate statutes
(e.g., MMPA, National Environmental Policy Act (EPA), and ESA) for
compliance with relevant standards. These analyses would consider the
environmental baseline at that time, including any impacts of the IHA
we have issued.
Should a renewal request be made, additional documentation would be
required from Narwhal that NMFS would make publicly available and would
use to verify that the activities are identical to those in the initial
IHA, are nearly identical such that the changes would have either no
effect on impacts to marine mammals or decrease those impacts, or are a
subset of activities already analyzed and authorized but not completed
under the initial IHA. NMFS would also confirm, among other things,
that the activities would occur in the same location; involve the same
species and stocks; provide for continuation of the same mitigation,
monitoring, and reporting requirements; and that no new information had
been received that would alter the prior analysis. If new information
has been received that would alter the prior analysis, that information
would be analyzed in the notice of the proposed Renewal IHA. A renewal
request would also contain a preliminary monitoring report,
specifically to verify that effects from the activities do not indicate
impacts of a scale or nature not previously analyzed. Any renewal
request is subject to an additional 15-day public comment period that
provides the public an opportunity to review these few documents,
provide any additional pertinent information and comment on whether
they think the criteria for a renewal have been met. Between the
initial 30-day comment period on these same activities and the
additional 15 days, the total comment period for a Renewal is 45 days.
In addition to the IHA renewal process being consistent with all
requirements under section 101(a)(5)(D), it is also consistent with
Congress' intent for issuance of IHAs to the extent reflected in
statements in the legislative history of the MMPA. Through the
provision for renewals in the implementing regulations, description of
the process and express invitation to comment on specific potential
renewals in the Request for Public Comments section of each proposed
IHA, the description of the process on NMFS' website, further
elaboration on the process through responses to comments such as these,
posting of substantive documents on the agency's website, and provision
of 30 or 45 days for public review and comment on all proposed initial
IHAs and renewals respectively, NMFS has ensured that the public has
full opportunity to meaningfully participate in the agency's decision-
making process.
Changes From the Proposed IHA to Final IHA
Several changes have been made to the Final IHA. NMFS has revised
the ensonified area calculations for the seismic airgun and the sparker
after coordination with the NMFS Alaska Regional Office and Narwhal. In
the proposed IHA, it was estimated that the total daily distance of
airgun use would be 48 km over a total of 12 days. Narwhal estimated
that it would take 2 days to survey each of the six drilling sites. The
total survey distance of a drilling site is 48 km (see Figure 1-6 of
Narwhal's application). Narwhal still expects that use of the seismic
airgun will take 2 days at each site. Given that the survey will take
place over 2 days per site, NMFS and Narwhal have revised the daily
distance of the airgun survey to 24 km. This change reduced the
ensonified area from 337.98 km\2\ to 184.95 km\2\ in this final IHA.
In the proposed IHA, NMFS assumed the daily distance for the
sparker use to be 48 km, similar to the seismic airgun. After further
review, NMFS determined that the total daily distance of 33.6 km was
appropriate for the operation of the sparker (see Figure 1-5 of
Narwhal's application). This reduced daily distance reduced the overall
ensonified area from 43.54 km\2\ to 30.66 km\2\ in this final IHA. NMFS
also determined that this distance would survey an entire drilling site
with the sparker in 1 day. Therefore, NMFS revised the total days for
the use of the sparker from 12 to 6 since each potential drilling site
will only require 1 day of sparker use. Both the seismic airgun and
sparker revisions have reduced the summer open water take estimates
from the proposed IHA and NMFS has updated the Estimated Take section
and tables 8, 9, and 11 accordingly.
In the Federal Register notice for the proposed IHA, the estimated
take numbers during the construction and operation of the ice trail
were calculated incorrectly. Inadvertently, an incorrect density of
0.61 ringed seals/km\2\, rather than 0.63 ringed seals/km\2\ as
described in the proposed IHA, was used to calculate the take estimate
resulting in 1,044 takes by Level B harassment. This take estimate has
been corrected using a density of 0.63 seals/km\2\ resulting in an
estimated 1,076 takes by Level B harassment for the construction and
operation of the ice trail. Tables 10 and 11 have been updated to
reflect this correction.
During the development of the Final IHA, Narwhal expressed new
practicability concerns regarding some of the mitigation and monitoring
measures in the proposed IHA. Below is a summary of resulting changes
from the proposed IHA to the final IHA.
Mitigation Changes
Narwhal requested and NMFS modified mitigation measure 4(a)(i) to
clarify that PSOs only be on duty when an acoustic source is active.
Narwhal noted that there may be times when the acoustic sources may be
in the water but not active to save deck space on the vessels being
used for the shallow hazard survey. This change satisfies the original
intent of the proposed measure while avoiding potential for unintended
practicability consequences.
Mitigation measure 4(a)(ii) has also been changed to reduce the
time for post-activity monitoring from 1-hour to 15 minutes once
acoustic sources cease operation. NMFS modified this measure, at
Narwhal's request, due to variable weather conditions that may occur
resulting in the timely retrieval of equipment and transit to safe
harbor. Additionally, given the shallow water of the survey sites, it
is anticipated any behavioral changes in marine mammals that may occur
would likely be observed within 15 minutes after sources have been
active. NMFS agrees with these mitigation changes and these changes
have been documented in the Mitigation section of this notice and the
final IHA issued to Narwhal.
Monitoring Changes
The PSO requirements described in section 5(a)(i)(1) of the IHA
states that all PSOs must be employed by a third-party observer
provider and must have no tasks other than to conduct observational
effort, collect data, and communicate with and instruct relevant vessel
crew. Narwhal raised concerns over the ability to safely accommodate
additional persons as third-party PSOs on the vessels used for the
shallow water hazard survey. Vessels being used
[[Page 40574]]
by Narwhal are very small (20 to 30 ft in length (6 to 9 m)) with
limited bunk and deck space. Narwhal has a total berthing capacity of
19 to 20 personnel across the three vessels being used during the
shallow water hazard survey. NMFS has revised the PSO requirements in
the IHA at 5(a)(i)(1). This change would authorize Narwhal to employ an
independent third-party lead PSO who will train Narwhal watch standers
as PSOs during the shallow water hazard survey and will retain
responsibility for decision making regarding necessary implementation
of required mitigation measures. The additional staff PSOs would be
used during the seismic survey portion of the shallow water hazard
survey where the use of two PSOs is required and during all acoustic
source use if the lead PSO approaches the maximum work limit of 12
hours.
Section 5(d)(i) of the IHA was a monitoring measure that requires
Narwhal to monitor a seal if found within 50 m of the centerline of the
ice trail to have an initial documentation period of 15 minutes and
then be observed every 6 hours after that period until the animal moves
farther than 50 m of the centerline of the ice trail or is no long
visible. Narwhal noted that there could be periods longer than 6 hours
where there is no activity on the trail and as the measure is currently
written, a dedicated environmental specialist would need to make a
dedicated observation trip to observe the animal. Given the remote
location of the trail and the highly variable weather conditions there
are safety concerns with sending an observer out when the trail in not
being actively used. Therefore, the measure has been revised to only
require observation of a seal within 50 m of the centerline of the
trial when the trail is being actively used.
Narwhal has also requested a change to section 5(d)(ii)(1)(a) of
the IHA for the ice trail monitoring measures related to surveying the
ice trail for seals or seal structures after March 1st. The measure in
the proposed IHA required Narwhal to complete these surveys every other
day. Given the remote nature of the Colville River Delta crossing and
the associated risk for personnel, Narwhal will be implementing a
convoy policy for transit of the entire sea ice trail which will
require a minimum of two vehicles traveling together on the trail. With
this policy, it is more logistically feasible for Narwhal to complete
these surveys every three days rather than every other day. NMFS agrees
with these monitoring changes and these changes have been documented in
the Monitoring section of this notice and the final IHA issued to
Narwhal.
All changes to the mitigation and monitoring requirements described
here and in further detail in the respective sections were made in
coordination with Narwhal and align with NMFS' statutory authority to
prescribe measures to affect the least practicable adverse impact on
the affected marine mammal species or stocks and to prescribe
appropriate monitoring requirements.
Description of Marine Mammals in the Area of Specified Activities
Sections 3 and 4 of the application summarize available information
regarding status and trends, distribution and habitat preferences, and
behavior and life history of the potentially affected species. NMFS
fully considered all of this information, and we refer the reader to
these descriptions instead of reprinting the information. Additional
information regarding population trends and threats may be found in
NMFS' Stock Assessment Reports (SARs; <a href="https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessments">https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessments</a>) and
more general information about these species (e.g., physical and
behavioral descriptions) may be found on NMFS' website (<a href="https://www.fisheries.noaa.gov/find-species">https://www.fisheries.noaa.gov/find-species</a>).
Table 1 lists all species or stocks for which take is likely from
the specified activities and authorized and summarizes information
related to the population or stock, including regulatory status under
the MMPA and 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. 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 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: <a href="https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessments">https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessments</a>.
Table 1--Species \1\ Likely Impacted by the Specified Activities
--------------------------------------------------------------------------------------------------------------------------------------------------------
Annual
ESA/ MMPA status; Stock abundance (CV, mortality
Common name Scientific name Stock strategic (Y/N) Nmin, most recent PBR and serious
\2\ abundance survey) \3\ injury (M/
SI) \4\
--------------------------------------------------------------------------------------------------------------------------------------------------------
Order Artiodactyla--Cetacea--Mysticeti (baleen whales)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Family Balaenidae:
Bowhead whale................... Balaena mysticetus.... Western Arctic........ E, D, Y 15,227 (0.165, 13,263, 133 57
2019).
--------------------------------------------------------------------------------------------------------------------------------------------------------
Order Carnivora--Pinnipedia
--------------------------------------------------------------------------------------------------------------------------------------------------------
Family Phocidae (earless seals):
Bearded Seal.................... Erignathus barbatus... Beringia.............. T, D, Y UND (UND, UND, 2013).. Unknown 6,709
(UND)
Ringed Seal..................... Pusa hispida.......... Arctic................ T, D, Y UND (UND, UND, 2013).. UND 6,459
[[Page 40575]]
Spotted Seal.................... Phoca largha.......... Bering................ -, -, N 461,625 (N/A, 423,237, 25,394 5,254
2013).
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ Information on the classification of marine mammal species can be found on the web page for The Society for Marine Mammalogy's Committee on Taxonomy
(<a href="https://marinemammalscience.org/science-and-publications/list-marine-mammal-species-subspecies/">https://marinemammalscience.org/science-and-publications/list-marine-mammal-species-subspecies/</a>).
\2\ Endangered Species Act (ESA) status: Endangered (E), Threatened (T)/MMPA status: Depleted (D). A dash (-) indicates that the species is not listed
under the ESA or designated as depleted under the MMPA. Under the MMPA, a strategic stock is one for which the level of direct human-caused mortality
exceeds PBR or which is determined to be declining and likely to be listed under the ESA within the foreseeable future. Any species or stock listed
under the ESA is automatically designated under the MMPA as depleted and as a strategic stock.
\3\ NMFS marine mammal stock assessment reports online at: <a href="https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessment-reports-region/">https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessment-reports-region/</a>. CV is coefficient of variation; Nmin is the minimum estimate of stock abundance.
\4\ These values, found in NMFS' SARs, represent annual levels of human-caused mortality plus serious injury from all sources combined (e.g., commercial
fisheries, ship strike). Annual M/SI often cannot be determined precisely and is in some cases presented as a minimum value or range.
A detailed description of marine mammals in the specified
geographic region, 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 (90 FR
21182, May 16, 2025). NMFS is not aware of any new relevant information
since publication of the notice of proposed IHA; therefore, detailed
descriptions are not provided here. Please refer to that Federal
Register notice for the proposed IHA (90 FR 21182, May 16, 2025) for
detailed descriptions.
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 whales)....................... 7 Hz to 36 kHz.
High-frequency (HF) cetaceans (dolphins, toothed whales, beaked 150 Hz to 160 kHz.
whales, bottlenose whales).
Very High-frequency (VHF) cetaceans (true porpoises, Kogia, river 200 Hz to 165 kHz.
dolphins, Cephalorhynchid, Lagenorhynchus cruciger & L. australis).
Phocid pinnipeds (PW) (underwater) (true seals).................... 40 Hz to 90 kHz.
Otariid pinnipeds (OW) (underwater) (sea lions and fur seals)...... 60 Hz to 68 kHz.
----------------------------------------------------------------------------------------------------------------
* 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.
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 (2024) for a review of available information
(<a href="https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-acoustic-technical-guidance-other-acoustic-tools">https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-acoustic-technical-guidance-other-acoustic-tools</a>).
Potential Effects of Specified Activities on Marine Mammals and Their
Habitat
The effects of underwater noise and visual disturbance from
Narwhal's specified 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 21182, May 16, 2025) included a
discussion of the effects of anthropogenic noise on marine mammals and
the potential effects of underwater noise and visual disturbance from
Narwhal's specified activities on marine mammals and their habitat.
There is no newly available relevant information that would change our
analyses or the results thereof; therefore, discussion of potential
effects is not provided here. Please refer to that Federal Register
notice for the proposed IHA (90 FR 21182, May 16, 2025).
Estimated Take of Marine Mammals
This section provides an estimate of the number of incidental takes
from Narwhal's specified activities, which
[[Page 40576]]
informed NMFS' consideration of ``small numbers,'' the negligible
impact determinations, and impacts to 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 will be by Level B harassment only, in the form of
disruption of behavioral patterns and/or TTS for individual marine
mammals resulting from exposure to noise resulting from use of airguns
and sparkers (i.e., geophysical survey) and the construction and
operation of ice trails. Based on the nature of the activity and the
anticipated effectiveness of the mitigation measures (i.e., shutdown
zones and ice trails specific measures) discussed in detail below in
the Mitigation section, Level A harassment (auditory injury (AUD INJ))
is neither anticipated nor authorized.
As described previously, no serious injury or mortality is
anticipated or authorized for these activities. Below we describe how
the take numbers were estimated.
For acoustic impacts, generally speaking, we estimate take by
considering: (1) acoustic thresholds above which NMFS believes the best
available science indicates marine mammals will be behaviorally
harassed or incur some degree of permanent hearing impairment; (2) the
area or volume of water that will be ensonified above these levels in a
day; (3) the density or occurrence of marine mammals within these
ensonified areas; and, (4) the number of days of activities. We note
that while these factors can contribute to a basic calculation to
provide an initial prediction of potential takes, additional
information that can qualitatively inform take estimates is also
sometimes available (e.g., previous monitoring results or average group
size). Below, we describe the factors considered here in more detail
and present the take estimates.
Acoustic Thresholds
NMFS recommends the use of acoustic thresholds that identify the
received level of underwater sound above which exposed marine mammals
are reasonably expected to be behaviorally harassed (equated to Level B
harassment) or to incur auditory injury of some degree (equated to
Level A harassment).
Level B Harassment--Though significantly driven by received level,
the onset of behavioral disturbance from anthropogenic noise exposure
is also informed to varying degrees by other factors related to the
source or exposure context (e.g., frequency, predictability, duty
cycle, duration of the exposure, signal-to-noise ratio, distance to the
source), the environment (e.g., bathymetry, other noises in the area,
predators in the area), and the receiving animals (hearing, motivation,
experience, demography, life stage, depth) and can be difficult to
predict (e.g., Southall et al., 2007, 2021, Ellison et al., 2012).
Based on what the available science indicates and the practical need to
use a threshold based on a metric that is both predictable and
measurable for most activities, NMFS typically recommends use of a
generalized acoustic threshold based on received level to estimate the
onset of behavioral harassment. NMFS generally predicts that marine
mammals are likely to be behaviorally harassed in a manner considered
to be Level B harassment when exposed to underwater anthropogenic noise
above root-mean-squared pressure received levels (RMS SPL) of 120 dB
(referenced to 1 micropascal (re 1 [mu]Pa)) for continuous (e.g.,
vibratory pile driving, drilling) and above RMS SPL 160 dB re 1 [mu]Pa
for non-explosive impulsive (e.g., seismic airguns) or intermittent
(e.g., scientific sonar) sources. Generally speaking, Level B
harassment take estimates based on these behavioral harassment
thresholds are expected to include any likely takes by TTS as, in most
cases, the likelihood of TTS occurs at distances from the source less
than those at which behavioral harassment is likely. TTS of a
sufficient degree can manifest as behavioral harassment, as reduced
hearing sensitivity and the potential reduced opportunities to detect
important signals (conspecific communication, predators, prey) may
result in changes in behavior patterns that will not otherwise occur.
Narwhal's activities include the use of impulsive (single airgun
and sparker) sources, and therefore, the RMS SPL threshold of 160 dB re
1 [mu]Pa is applicable. Narwhal's activities also include the use of
construction equipment while building ice trials, which will produce
continuous sounds, for which use of the RMS SPL threshold of 120 dB re
1 [mu]Pa is applicable. However, as noted in the Marine Mammal Effects
section of the proposed IHA (90 FR 21182, May 16, 2025), that threshold
is not expected to be met for the ice trail construction equipment that
will be used by Narwhal and, in general, disturbance of seals due to
ice trails activities may be attributable broadly to a suite of
potential sources of disturbance, including acoustic or visual
disturbance.
Level A Harassment--NMFS' Updated Technical Guidance for Assessing
the Effects of Anthropogenic Sound on Marine Mammal Hearing (Version
3.0) (NMFS, 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). Narwhal's
activity includes the use of impulsive (i.e., single airgun and
sparker) sources, and no take of marine mammals is expected to result
from exposure to continuous noise produced by Narwhal's activities
(e.g., ice trail construction).
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:
<a href="https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-acoustic-technical-guidance-other-acoustic-tools">https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-acoustic-technical-guidance-other-acoustic-tools</a>.
Table 3--Thresholds Identifying the Onset of Permanent Threshold Shift
----------------------------------------------------------------------------------------------------------------
AUD INJ onset thresholds * (received level)
Hearing group ------------------------------------------------------------------------
Impulsive Non-impulsive
----------------------------------------------------------------------------------------------------------------
Low-Frequency (LF) Cetaceans........... Cell 1: L0-pk,flat: 222 Cell 2: LE,LF,24h: 197 dB.
dB; LE,LF,24h: 183 dB.
[[Page 40577]]
High-Frequency (HF) Cetaceans.......... Cell 3: L0-pk,flat: 230 Cell 4: LE,HF,24h: 201 dB.
dB; LE,HF,24h: 193 dB;.
Very High-Frequency (VHF) Cetaceans.... Cell 5: L0-pk,flat: 202 Cell 6: LE,VHF,24h: 181 dB.
dB; LE,,VHF,24h: 159 dB.
Phocid Pinnipeds (PW) (Underwater)..... Cell 7: L0-pk.flat: 223 Cell 8: LE,PW,24h: 195 dB.
dB; LE,PW,24h :183 dB.
Otariid Pinnipeds (OW) (Underwater).... Cell 9: L0-pk,flat: 230 Cell 10: LE,OW,24h: 199 dB.
dB; LE,,OW,24h: 185 dB.
IN-AIR:
Phocid Pinnipeds (PA).............. Cell 11: L0-pk.flat: 162 Cell 12: LE,PA,24h: 154 dB.
dB; LE,,PA,24h: 140 dB.
Otariid Pinnipeds (OA)............. Cell 13: L0-pk,flat: 177 Cell 14: LE,OA,24h: 177 dB.
dB; LE,OA,24h: 163 dB.
----------------------------------------------------------------------------------------------------------------
* Dual metric thresholds for impulsive sounds: Use whichever results in the largest isopleth for calculating AUD
INJ onset. If a non-impulsive sound has the potential of exceeding the peak sound pressure level thresholds
associated with impulsive sounds, these thresholds are recommended for consideration.
Note: Peak sound pressure level (L0-pk) has a reference value of 1 [micro]Pa, and weighted cumulative sound
exposure level (LE,) has a reference value of 1[micro]Pa\2\s. In this table, thresholds are abbreviated to be
more reflective of International Organization for Standardization standards (ISO 2017). The subscript ``flat''
is being included to indicate peak sound pressure are flat weighted or unweighted within the generalized
hearing range of marine mammals (i.e., 7 Hz to 165 kHz). The subscript associated with cumulative sound
exposure level thresholds indicates the designated marine mammal auditory weighting function (LF, HF, and VHF
cetaceans, and PW and OW pinnipeds) and that the recommended accumulation period is 24 hours. The weighted
cumulative sound exposure level thresholds could be exceeded in a multitude of ways (i.e., varying exposure
levels and durations, duty cycle). When possible, it is valuable for action proponents to indicate the
conditions under which these thresholds will be exceeded.
Ensonified Area for the Single Airgun
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.
Sound propagation and the distances to the sound isopleths for
marine mammal hearing groups are defined by NMFS for Level A harassment
of marine mammals under the 2024 Technical Acoustic Guidance. To assess
the potential for exposure to underwater sounds that might exceed
relevant threshold criteria during seismic surveys, Narwhal conducted
noise modeling of the single 105 cu. in. (1,721 cc) airgun at a
proposed survey site to determine sound source levels that are shown in
table 4 based on Gundalf Designer software, which is a seismic source
modelling software package that may be used to estimate source levels
of active acoustic sources. The estimated distances discussed in this
section are used for estimating potential exposures to noise exceeding
relevant harassment criteria.
Table 4--Estimated Underwater Sound Source Levels for the Single Airgun
------------------------------------------------------------------------
Source level type (measured at site 10) Source levels
------------------------------------------------------------------------
Peak sound pressure level (Pk SPL) (dB re 1 [mu]Pa @1 231
m)....................................................
Root-mean-square sound pressure level (rms SPL) (dB re 204
1 [mu]Pa @1 m with a 90%-energy pulse duration of 12.5
milliseconds).........................................
Sound exposure level (SEL) (dB re [mu]Pa2[middot]s @1 193
m)....................................................
------------------------------------------------------------------------
Estimated Level A harassment zone distances were modeled for the
single 105-cu. in. (1,721 cc) airgun, which is an impulsive, mobile
source. Estimated distances to Level A harassment thresholds for
weighted SEL<INF>24hr</INF> are presented here and in greater detail in
Appendix B of the Narwhal application. Shallow hazard surveys will be
conducted one site at a time. Each survey block is approximately 2,400
m by 2,400 m in area. The airgun will fire every 12.5 m along a track
line (i.e., every 6 or 7 seconds traveling at a speed of 2 m/s).
Therefore, there will be an estimated 192 shots per track line. The
area of ensonification for the seismic survey was calculated by
multiplying the estimated distances (in km) to the harassment
thresholds by the distance of the seismic track line (in km) to be
surveyed each day. A single track line is approximately 2 km in length,
which will take approximately 20 minutes to shoot assuming a vessel
speed of 2 m/s. Narwhal expects that in a 24 hour24-hour, approximately
24 km can be surveyed at each potential drilling site. Given the total
distance to survey one drilling site is 48 km, it is expected to take 2
days to complete each site and a total of 12 days to complete the
survey at all six drilling sites.
Level A harassment zones were calculated using the source levels
modeled from the Gundalf software. A fluid parabolic equation modelling
algorithm (RAMGeo) was used to calculate the propagation of noise from
the airgun source. The noise source was assumed to be omnidirectional
and modelled as a point source. Only low frequency acoustic energy (<1
kHz, e.g., single airgun) was modeled. Greater detail on the modeling
methods used by Narwhal is available in Section 6.2.3.1 and Appendix B
of Narwhal's application. Modeling results estimated Level A harassment
zone distances for LF cetaceans as 1,076 m (3,530 ft) and for phocids
as 322 m (1,056 ft) from the seismic source vessel while the airgun is
operating.
The following equation is used to estimate the ensonified area:
Mobile Ensonification Area (km2) Equation = Distance * (2 * Threshold
Value/1,000) + (Pi * (Threshold Value/1,000)-2).
Following the same process, with additional procedures described in
Appendix B of Narwhal's application to convert modeled SEL values to
RMS SPLs, Narwhal estimated the distance to the 160 dB re 1 [mu]Pa
Level B harassment threshold to be 3,188 m (10,459 ft).
[[Page 40578]]
Narwhal then used the mobile ensonification equation above to calculate
the total area of the Level B harassment, which resulted in an area of
184.95 km\2\ (71 mi\2\). It should be noted that since the study area
is in close proximity to shore, some sound is likely to be truncated by
land to a certain extent.
Ensonified Area for the Sparker
Using data from Crocker and Fratantonio (2016), NMFS estimated
source levels for the sparker to be 213 db RMS while operating at 1,000
joules of energy across 240 active tips.
Take by Level A harassment is not expected during the use of the
sparker given the small injury zone sizes expected with the sparker use
and likelihood that marine mammals will avoid the sound source before
incurring auditory injury. Using the source levels above, NMFS
calculated the estimated distance to the 160 dB re 1 [mu]Pa Level B
harassment threshold to be 447 m (1,467 ft). NMFS estimated the total
distance the sparker will survey in a 24-hour period at 33.6 km (21
mi.). Given there are six sites, it is estimated that the sparker
survey can be completed in 6 days. NMFS then used the same mobile
ensonification equation to calculate the total area of the Level B
harassment zone which resulted in an area of 30.66 km\2\ (12 mi\2\).
Disturbance Area for the Ice Trails on the Colville River Delta
Ringed seals are the only marine mammal expected to be present in
the project area during winter activities. To estimate incidents of
disturbance that may constitute a take, the total area of potential
disturbance (i.e., ice trails) associated with construction and
maintenance of specific portions of the coastal sea ice trail are
included in the estimate. As noted in the Description of Marine Mammals
in the Area of Specified Activities section, ground sea ice (occurring
>3 m of water depth) is not considered suitable habitat for ringed
seals. The coastal sea ice trail will be on grounded ice; however, the
Colville River Delta is included in the take estimate to account for
the possibility that ringed seals may occur in that section of the
route given the potential for open leads or cracks in the sea ice,
which could provide habitat for ringed seals. For the offshore sea ice
trails/roads in west Harrison Bay, water depths at planned pad
locations are less than 3 m (average); therefore, the majority of ice
trails/roads in west Harrison Bay will be on grounded ice or limited
portions of floating ice in water depths between 1.6 m (5 ft) and 3 m
(10 ft) and not expected to provided suitable ringed seal habitat.
The width of the coastal sea ice trail across the Colville River
Delta is defined as 170 m (558 ft) on either side of the ice trail
centerline, or a total width of 340 m (1,115 ft). The total width (340
m or 0.34 km (.21 mi)) is then multiplied by the portion of the total
length of trail/roads transiting ringed seal habitat, as described
above. The linear distance of the coastal sea ice trail across the
Colville River Delta is 57.8 km (36 mi). To calculate the potential
exposure area, linear distance is multiplied by the total width (i.e.,
57.8 km * 0.34 km = 19.65 km\2\ (12.2 mi\2\)). The calculated area of
disturbance (19.65 km\2\) is applied to activity associated with
Narwhal's construction, operation, and demobilization phases.
Marine Mammal Density Estimates
In this section, we provide information about the occurrence of
marine mammals, including density or other relevant information that
will inform the take calculations.
Narwhal and NMFS used a variety of data sources to estimate
appropriate marine mammal densities for evaluation of potential take
incidental to the activities. Neither NMFS nor Narwhal relied on data
available from Ca[ntilde]adas et al. 2020 (Duke University Arctic Study
Area Models; see <a href="https://seamap.env.duke.edu/models/Duke/Arctic/">https://seamap.env.duke.edu/models/Duke/Arctic/</a>). For
bowhead whales, more recent data (through 2021) is available in the
Aerial Surveys of Arctic Marine Mammals (ASAMM) dataset, opposed to the
Arctic Study Area Models where data through 2019 was used. For bearded
seal, estimates of density are available but, as noted in
Ca[ntilde]adas et al. (2020), there is a high degree of observer bias,
which leads to uncertainty in species identification and, therefore,
uncertainty in model outputs and resultant densities. Therefore, data
from previous, site-specific vessel surveys (Funk et al. 2010) provide
the best estimates of species proportions in Harrison Bay during the
open water period. Neither spotted seal nor ringed seal density
estimates are available from Ca[ntilde]adas et al. (2020).
Bowhead Whale
Bowhead whale sighting data from ASAMM aerial survey Block 3, which
includes Harrison Bay, for the period 2012-2021 were used to estimate
bowhead density near the project area. For reference, Harrison Bay is
approximately 250 km\2\ relative to the larger total area of ASAMM
survey Block 3. Harrison Bay also is not preferred habitat of bowhead
whales given the lack of observations from within the bay as noted
above in the Description of Marine Mammals in the Area of Specified
Activities Section. Therefore, the density estimates presented here
could be slightly higher than expected in the project area. Densities
were calculated by Narwhal using a two-step approach. First, a sighting
rate is calculated based on whales per km, then transect length (km) is
multiplied by the effective strip width of the transect using the
modeled effective strip width for bowhead whales observed during aerial
surveys conducted from an Aero Commander airplane (1.15 km (CV = 0.08))
(Ferguson and Clarke 2013). Therefore, whales per km\2\ = whales per
km/(2 * 1.15km). For survey Block 3, the average density estimate in
summer is 0.009 bowhead whales per km\2\ (table 5). The average fall
density was calculated at 0.017 bowhead whales per km\2\; however,
since the shallow water hazard survey work will be completed in the
summer, NMFS used the summer density for calculating take estimates.
As noted in the Description of Marine Mammals in the Area of
Specified Activities section, we do not expect bowhead whales to be
present during Narwhal's winter or spring activities.
Table 5--Bowhead Whale Sighting Data From 2012 Through 2020 and Resulting Densities
----------------------------------------------------------------------------------------------------------------
Bowhead whale Bowhead Bowhead
Survey year Survey time period On transect sightings on whales per whales per
distance (km) transect km km\2\
----------------------------------------------------------------------------------------------------------------
2012 Summer..................... Jul-Aug............ 1,742 1 0.001 0.004
2012 Fall....................... Sep-Oct............ 1,388 26 0.019 0.083
2013 Summer..................... Jul-Aug............ 950 8 0.009 0.0039
2013 Fall....................... Sep-Oct............ 1,217 7 0.006 0.0026
2014 Summer..................... Jul-Aug............ 1,290 0 0.000 0.000
[[Page 40579]]
2014 Fall....................... Sep-Oct............ 1,927 1 0.001 0.0004
2015 Summer..................... Jul-Aug............ 1,570 0 0.000 0.000
2015 Fall....................... Sep-Oct............ 1,949 66 0.034 0.0148
2016 Summer..................... Jul-Aug............ 1,845 259 0.141 0.0613
2016 Fall....................... Sep-Oct............ 1,959 61 0.032 0.0139
2017 Summer..................... Jul-Aug............ 2,188 6 0.003 0.0013
2017 Fall....................... Sep-Oct............ 2,269 35 0.016 0.0070
2018 Summer..................... Jul-Aug............ 2,049 7 0.004 0.0017
2018 Fall....................... Sep-Oct............ 2,390 32 0.014 0.0061
2019 Summer..................... Jul-Aug............ 2,822 7 0.003 0.0013
2019 Fall....................... Sep-Oct............ 3,853 8 0.003 0.0013
2020 Fall....................... Sep-Oct............ 654 32 0.049 0.0213
2021 Fall....................... Sep-Oct............ 1,637 58 0.035 0.0154
----------------------------------------------------------
Summer Average.............. ................... .............. ............... ........... 0.009
Fall Average................ ................... .............. ............... ........... 0.017
----------------------------------------------------------------------------------------------------------------
Bearded and Spotted Seals
Spring aerial surveys conducted as part of industry monitoring for
the Northstar production facility provide limited sighting numbers of
bearded seals from 1999-2002 (Richardson and Williams, 2002 and 2003).
Given the lack of bearded seal data in Harrison Bay, NMFS reviewed
survey data from Funk et al. (2010). This information represents a
compilation of monitoring data gathered during vessel-based seismic
operations in the Beaufort Sea from 2006-2008. NMFS considers this the
best available data to derive a density estimate for bearded seals and
spotted seals (see below). This survey observed ringed seals, bearded
seals, spotted seals, ribbon seals, and some unidentified seals.
Narwhal proposed to base the percentage of seals present in the survey
area as a percentage of the total identified seals and multiplying that
percentage by the ringed seal summer/fall density. The density that
Narwhal proposed in their application was 0.03 bearded seals/km\2\.
NMFS expects that relying on this method to calculate the percentage of
bearded and spotted seals may result in underestimation of potential
seal occurrence.
Therefore, NMFS modified this approach and calculated the bearded
seal percentage as a proportion of the observed ringed seals in the
Funk et al. (2010) survey. NMFS took this approach because the bearded
seal density was being derived from the ringed seal summer/fall
density, and such does not utilize the best available scientific
information and likely underestimates the potential for bearded seal
take. Percentages calculated using NMFS method are found in table 6 and
differ from the Narwhal application. Based on this ratio, NMFS expects
that the bearded seal density will be 21.3 percent of the summer/fall
ringed seal density (0.213 * 0.32 = 0.07 bearded seals/km\2\).
Similar to the method used for bearded seals, NMFS derived the
density of spotted seals by first determining the ratio of the number
spotted seals observed to the number of ringed seals observed from Funk
et al. (2010) (table 6). Based on this ratio, NMFS expects that the
spotted seal density will be 34.8 percent of the summer/fall ringed
seal density (0.348 * 0.32 = 0.11 spotted seals/km\2\).
Table 6--Bearded Seal and Spotted Seal Ratios Based on the Observed
Ringed Seals From Funk et al. (2010)
------------------------------------------------------------------------
Species Percentage of ringed seal
------------------------------------------------------------------------
Bearded Seal.............................. 21.3
Spotted Seal.............................. 34.8
------------------------------------------------------------------------
Ringed Seal
Winter/Spring Density--Narwhal originally proposed in their
application the use of data from a number of on-ice surveys and aerial
surveys for ringed seal density estimates for on-ice periods. These
included site-specific surveys for ringed seals along the Beaufort Sea
coast that were conducted in association with industry activities in
the late 1980s and continued into the 2020s (Kelly et al. 1986; Frost
and Burns 1989; Frost and Lowry 1987; Richardson and Williams 2001,
2002, and 2004; Frost et al. 2004; Moulton et al. 2005; and Quakenbush
et al. 2022 and 2023). Several of these studies estimated approximate
seal densities by considering the detection by trained dogs of seal
structures such as breathing holes, haulout lairs, or pupping lairs.
Aerial surveys were also included in the density estimate that was
completed in the spring of the year. Narwhal proposed a ringed seal
density estimate for the winter/spring season of 0.49 seals/km\2\ (see
table 6-3 in Narwhal's application).
However, NMFS determined that a different approach to calculate the
ringed seal density is more appropriate, as several of the papers used
by Narwhal included inconsistent correction factors for seal abundance
(Quakenbush 2022 and 2023), some of the data Narwhal proposed for use
was approximately 40 years old, and because NMFS assumed that aerial
surveys provide a more accurate density calculation than on-ice surveys
given they are actual seal counts rather than counts of potential seal
structures. NMFS relied only on spring aerial surveys conducted in
1997-2002 (Moulton et al. 2005) and 1996-1999 (Frost et al. 2004),
which included a
[[Page 40580]]
broad section of the total survey area. Densities reported by Moulton
et al. (2005) were lower than those estimated by Frost et al. (2004)
for that same area: 0.43 vs. 0.73 seals/km\2\ in 1997, 0.39 vs. 0.64
seals/km\2\ in 1998, and 0.63 vs. 0.87 seals/km\2\ in 1999. Narwhal had
noted that the differences in density were mainly because of
differences in ice composition (fast ice vs. pack ice) between Frost et
al. (2004) and Moulton et al. (2005). Specifically, Narwhal cited an
average observed density of seals on fast ice over the 4 year period
ranging from 0.57 to 1.14 seals/km\2\. On pack ice, observed densities
ranged from 0.92 to 1.33 seals/km\2\ (Frost et al 2004). Given these
differences, Narwhal calculated the average ringed seal density using
data inclusive of waters less than 3 m in depth only from the Moulton
et al. (2005) surveys, which resulted in the 0.49 seals/km\2\ density.
NMFS considered this information but does not agree the higher
observed densities reported by Frost et al. (2004) are due to
differences in the composition of sea ice surveyed between the two
studies, since these observed densities are for the same area and
years. Further, Frost et al. (2004) noted that the two studies were
similar in timing and methods. For these reasons, NMFS calculated an
average density of 0.63 seals/km\2\ using these two data sources (table
7).
Table 7--Ringed Seal Aerial Survey Densities for Winter/Spring
------------------------------------------------------------------------
Observed density
Source Year (seals/km\2\)
------------------------------------------------------------------------
Moulton et al. (2005).................. 1997 0.43
Moulton et al. (2005).................. 1998 0.39
Moulton et al. (2005).................. 1999 0.63
Moulton et al. (2005).................. 2000 0.47
Moulton et al. (2005).................. 2001 0.54
Moulton et al. (2005).................. 2002 0.83
Frost et al. (2004).................... 1996 0.81
Frost et al. (2004).................... 1997 0.73
Frost et al. (2004).................... 1998 0.64
Frost et al. (2004).................... 1999 0.87
--------------------------------
Average............................ ........... 0.63
------------------------------------------------------------------------
Summer/Fall Density--Hauser et al. (2008) summarized sighting data
from a 2008 seismic survey (inside and outside the barrier islands)
near Thetis Island north and east of the action area. Hauser et al.
(2008) found that most seal sightings were observed in waters seaward
of the barrier islands (~76 percent of 38 sightings). Sightings of
ringed seals in the shallow waters shoreward of the barrier islands
were substantially lower. Narwhal's action area is most similar to what
Hauser et al. (2008) defined as shallow waters. Hauser et al. (2008)
reported a seal density for all species combined of 0.11 seals/km\2\
for shallow waters during open-water conditions.
While this average seal density based on actual observations does
not reflect seals that may not have been visible to observers, several
publications acknowledge that during open-water months, ringed seals
are more abundant farther offshore (Harwood and Stirling 1992, Kelly et
al. 2010b, McLaren 1958, Von Duyke et al. 2020). For example, 1999
aerial surveys conducted over 8 days near Prudhoe Bay reported that the
density of seals visible near shore decreased compared to the density
offshore (Richardson and Williams 2000b). Narwhal estimated a summer
density for ringed seals by using a 50 percent conversion factor of the
winter/spring densities (table 8). NMFS agrees with this methodology
and estimated the summer/fall density to be 0.32 seals/km\2\ (i.e., 50
percent of 0.63 seals/km\2\ the winter/spring density).
Take Estimation
Here, we describe how the information provided above is synthesized
to produce a quantitative estimate of the take that is reasonably
likely to occur and authorized in the IHA.
For all marine mammal species, NMFS does not expect take by Level A
harassment during any activities. Narwhal proposes to implement an
1,100 m (3,608 ft) shutdown zone for LF cetaceans and a 350 m (1,148
ft) shutdown zone for phocids during the operation of the single 105
cu. in. (1,721 cc) airgun. These zones are larger than the respective
Level A harassment zones and therefore, will reduce the already low
likelihood of take by Level A harassment. Take by Level A harassment is
unlikely because Narwhal will shut down the single airgun before a
marine mammal will enter the Level A harassment zone. Take by Level A
harassment is also unlikely because animals will avoid the area of
active acoustic sources.
Summer/Fall Take Estimates--As described above, the estimated Level
B harassment area for the seismic airgun is 184.95 km\2\ and for the
sparker 30.66 km\2\. Given that the Level B harassment zone of 447 m
for the sparker, it is expected that Narwhal will implement a shutdown
zone of 500 m for bowhead whales and no take of bowhead whales will
occur during sparker use. Similar to the single airgun, Narwhal will
shut down the sparker before a marine mammal will enter the Level A
harassment zone and therefore prevent take by Level A harassment. This
area was used to determine the number of take based on the densities of
marine mammals as described above multiplied by the number of days
(i.e., 12 days of seismic survey and sparker use) of activity. NMFS
expects the number of take for each species as outlined in tables 8 and
9.
[[Page 40581]]
Table 8--Estimated Level B Harassment of Marine Mammals During Use of the Seismic Airgun
----------------------------------------------------------------------------------------------------------------
Total take
Density Ensonified Days of estimate by
Species (animal/km\2\) area of the activity Level B
airgun (km\2\) harassment
----------------------------------------------------------------------------------------------------------------
Bowhead Whale...................................... 0.009 184.95 12 20
Ringed Seal........................................ 0.320 184.95 12 710
Bearded Seal....................................... 0.070 184.95 12 155
Spotted Seal....................................... 0.110 184.95 12 244
----------------------------------------------------------------------------------------------------------------
Table 9--Estimated Level B Harassment of Marine Mammals During Use of the Sparker
----------------------------------------------------------------------------------------------------------------
Ensonified Total take
Density area of the Days of estimate by
Species (animal/km\2\) sparker activity Level B
(km\2\) harassment
----------------------------------------------------------------------------------------------------------------
Ringed Seal........................................ 0.320 30.66 6 59
Bearded Seal....................................... 0.070 30.66 6 13
Spotted Seal....................................... 0.110 30.66 6 20
----------------------------------------------------------------------------------------------------------------
Winter/Spring Take Estimate--NMFS estimated the take estimates
based on the total construction and operation area that will be
affected during the winter period. As discussed previously, the total
potential disturbance area of the Colville River Delta sea ice trail is
estimated to be 19.65 km. NMFS multiplied the area of the sea ice trail
with the winter/spring density of ringed seals for the construction,
operation, and demobilization activities to determine the total number
of potential takes by Level B harassment for ringed seals (table 10).
Table 10--Estimated Level B Harassment of Ringed Seals During Colville River Delta Coastal Sea Ice Trail
Activities
----------------------------------------------------------------------------------------------------------------
Total take
Area of Density Days of estimate by
Sea ice trail activity disturbance (animal/km\2\) activity Level B
(km\2\) harassment
----------------------------------------------------------------------------------------------------------------
Construction....................................... 19.65 0.63 25 309
Operation.......................................... 19.65 0.63 40 495
Demobilization..................................... 19.65 0.63 22 272
------------------------------------------------------------
Total.......................................... .............. .............. ........... 1,076
----------------------------------------------------------------------------------------------------------------
The total number of take estimated for Narwhal's specified activity
is available in table 11.
Table 11--Summary of All Marine Mammal Exposures Requested by Species
--------------------------------------------------------------------------------------------------------------------------------------------------------
Total take by
Level B Total take by Take as a
harassment Level B harassment Total take by Population percentage
Species Stock during the during ice trail Level B estimate of the
shallow water construction and harassment population
hazard survey operation
--------------------------------------------------------------------------------------------------------------------------------------------------------
Bowhead Whale............................ Western Artic.............. 20 0 20 15,277 0.1
Ringed Seals............................. Artic...................... 769 1,076 1,845 \a\ 342,836 0.5
Bearded Seals............................ Beringia................... 168 0 168 \b\ 301,836 <0.1
Spotted Seals............................ Bering..................... 264 0 264 461,625 <0.1
--------------------------------------------------------------------------------------------------------------------------------------------------------
\a\ Conn et al. (2014) calculated an abundance estimate of 171,418 using a subset of aerial survey data collected in 2012 by Moreland et al. (2013) that
covered the entire ice-covered portions of the Bering Sea. This estimate is considered to be low and was multiplied by a factor of two (Young et al.
2023).
\b\ Conn et al. (2014), using a sub-sample of the data collected from the U.S. portion of the Bering Sea in 2012, calculated an abundance estimate of
301,836 bearded seals (Young et al. 2023).
Effects of Specified Activities on Subsistence Uses of Marine Mammals
The availability of the affected marine mammal stocks or species
for subsistence uses may be impacted by this activity. Measures
included in this IHA to reduce the impacts of the activity on
subsistence uses are described in the Mitigation section. Last, the
information from this section and the Mitigation section is analyzed to
determine whether the necessary findings may be
[[Page 40582]]
made in the Unmitigable Adverse Impact Analysis and Determination
section.
The effects of Narwhal's specified activities were discussed in
detail in the notice of the proposed IHA (90 FR 21182, May 16, 2025).
There is no newly available relevant information that would change our
analyses or the results thereof; therefore, discussion of effects are
not provided here. Please refer to the notice of proposed IHA (90 FR
21182, May 16, 2025).
Mitigation
In order to issue an IHA under section 101(a)(5)(D) of the MMPA,
NMFS must set forth the permissible methods of taking pursuant to the
activity, and other means of effecting the least practicable impact on
the species or stock and its habitat, paying particular attention to
rookeries, mating grounds, and areas of similar significance, and on
the availability of the species or stock for taking for certain
subsistence uses. NMFS regulations require applicants for incidental
take authorizations to include information about the availability and
feasibility (economic and technological) of equipment, methods, and
manner of conducting the activity or other means of effecting the least
practicable adverse impact upon the affected species or stocks, and
their habitat (50 CFR 216.104(a)(11)).
In evaluating how mitigation may or may not be appropriate to
ensure the least practicable adverse impact on species or stocks and
their habitat, as well as subsistence uses where applicable, NMFS
considers two primary factors:
(1) The manner in which, and the degree to which, the successful
implementation of the measure(s) is expected to reduce impacts to
marine mammals, marine mammal species or stocks, and their habitat, as
well as subsistence uses. This considers the nature of the potential
adverse impact being mitigated (likelihood, scope, range). It further
considers the likelihood that the measure will be effective if
implemented (i.e., probability of accomplishing the mitigating result
if implemented as planned), the likelihood of effective implementation
(i.e., probability implemented as planned), and;
(2) The practicability of the measures for applicant
implementation, which may consider such things as cost and impact on
operations.
The mitigation requirements described in the following discussion
were contained in Narwhal's in its adequate and complete application or
are the result of subsequent coordination between NMFS and Narwhal.
Narwhal has agreed that all of the mitigation measures are practicable.
NMFS has fully reviewed the specified activities and the mitigation
measures to determine if the mitigation measures would result in the
least practicable adverse impact on marine mammals and their habitat,
as required by the MMPA, and has determined the measures are
appropriate. NMFS describes these below as mitigation requirements and
has included them in the issued IHA.
Mitigation for Shallow Water Hazard Surveys
Vessels used during the surveys will not allow lines to remain in
the water unless both ends are under tension and affixed to vessels or
gear. No materials capable of becoming entangled around marine mammals
will be discarded into marine waters.
Vessel-Visual Based Mitigation Monitoring--Visual monitoring
requires the use of trained observers (herein referred to as PSOs) to
scan the ocean surface visually for the presence of marine mammals.
PSOs shall establish and monitor a pre-start clearance zone (shutdown
zones in table 11) and, to the extent practicable, a Level B harassment
zone (table 11). These zones shall be based upon the radial distance
from the edges of the acoustic source (rather than being based around
the vessel itself). The shutdown zones are based off the size of the
Level A harassment zone with slightly larger areas to ensure shut down
before the animal enters the harassment zone. During pre-start
clearance (i.e., before ramp-up begins), the pre-start clearance zone
is the area in which observations of marine mammals within the zone
will prevent airgun and sparker operations from beginning (i.e., ramp-
up). The pre-start clearance zone will encompass the shutdown zones.
During survey operations (e.g., any day on which use of the
acoustic source is planned to occur, and whenever the acoustic source
is activated in the water), a minimum of two PSOs during the operation
of the airgun and a minimum of one PSO during the operation of the
sparker must be on duty and conducting visual observations at all times
during daylight hours (i.e., from 30 minutes prior to sunrise through
30 minutes following sunset). Visual monitoring must begin no less than
15 minutes prior to use of the acoustic source and must continue 15
minutes after use of the acoustic source ceases. Visual PSO(s) must
coordinate to ensure 360-degree visual coverage around the vessel from
the most appropriate observation posts, and must conduct visual
observations using binoculars and the naked eye while free from
distractions and in a consistent, systematic, and diligent manner.
Any observations of marine mammals by crew members shall be relayed
to the PSO team. During good conditions (e.g., daylight hours, Beaufort
sea state (BSS) 3 or less), visual PSOs shall conduct observations when
the acoustic source is not operating for comparison of sightings rates
and behavior with and without use of the acoustic source and between
acquisition periods, to the maximum extent practicable.
Visual PSOs may be on watch for a maximum of 4 consecutive hours
followed by a break of at least 1 hour between watches and may conduct
a maximum of 12 hours of observation per 24-hour period.
Pre-Start Clearance and Ramp-Up-- A ramp-up procedure, involving a
gradual increase in source level output, is not required for use of the
airgun but is required at the start of the activation of the sparker
when technically feasible. Operators should ramp up sparker source to
half power for 5 minutes and then proceed to full power. A 15-minute
pre-start clearance observation period must occur prior to the start of
ramp-up. The intent of pre-start clearance observation (15 minutes) is
to ensure no marine mammals are within the shutdown zones prior to the
beginning of ramp-up. The intent of ramp-up is to warn marine mammals
of pending operations and to allow sufficient time for those animals to
leave the immediate vicinity. A 15-minute pre-start clearance period is
required for all species for this project due to the quick succession
of track lines and in general the shallow water of the project area.
All sound source operators must adhere to the following pre-start
clearance and ramp-up requirements:
<bullet> The operator must notify a designated PSO of the planned
start of ramp-up as agreed upon with the lead PSO; the notification
time should not be less than 60 minutes prior to the planned ramp-up in
order to allow the PSOs time to monitor the shutdown zones for 15
minutes prior to the initiation of ramp-up (pre-start clearance).
During this 15-minute pre-start clearance period, the entire applicable
shutdown zones must be visible, except as indicated below.
<bullet> Source use shall be scheduled so as to minimize the time
spent with the source activated prior to the start of acquisition.
<bullet> A visual PSO conducting pre-start clearance observations
must be notified again immediately prior to initiating ramp-up
procedures and the operator
[[Page 40583]]
must receive confirmation from the PSO to proceed.
<bullet> Any PSO on duty has the authority to delay the start of
survey operations if a protected species is detected within the
applicable pre-start clearance zone.
<bullet> The operator must establish and maintain clear lines of
communication directly between PSOs on duty and crew controlling the
acoustic source to ensure that mitigation commands are conveyed swiftly
while allowing PSOs to maintain watch.
<bullet> Ramp-up (sparker) or source use (airgun) may not be
initiated if any marine mammal is within the applicable shutdown zone.
If a marine mammal is observed within the applicable shutdown zone
during the 15-minute pre-start clearance period, ramp-up may not begin
until the animal(s) has been observed exiting the zones or until an
additional time period has elapsed with no further sightings (15
minutes for all marine mammals).
<bullet> PSOs must monitor the shutdown zones 15 minutes before and
during ramp-up, and ramp-up must cease and the source must be shut down
upon observation of a marine mammal within the applicable shutdown
zone.
<bullet> Ramp-up may occur at times of poor visibility, including
nighttime, if appropriate visual monitoring has occurred with no
detections of protected species in the 15 minutes prior to beginning
ramp-up.
<bullet> If the sparker is shut down for brief periods (i.e., less
than 30 minutes) for reasons other than implementation of prescribed
mitigation (e.g., mechanical difficulty), it may be activated again
without ramp-up if PSOs have maintained constant visual observation and
no detections of protected species have occurred within the applicable
shutdown zone. For any longer shutdown, pre-start clearance observation
and ramp-up are required.
Shutdown Procedures
Any PSO on duty will have the authority to call for the shut down
of the acoustic sources, as appropriate. The operator must also
establish and maintain clear lines of communication directly between
PSOs on duty and crew controlling the acoustic sources to ensure that
shutdown commands are conveyed swiftly while allowing PSOs to maintain
watch. Narwhal must implement shutdown if a marine mammal species for
which take was not authorized or a species for which authorization was
granted but the authorized takes have been met approaches the Level B
harassment zone. If the seismic activity is halted due to the presence
of a marine mammal, the activity may not resume until either the animal
has voluntarily exited and been visually confirmed beyond the shutdown
zone indicated in table 12, or 15 minutes have passed without re-
detection of any marine mammal.
Table 12--Shutdown Zones and Level B Harassment Zones for Each Activity
----------------------------------------------------------------------------------------------------------------
Shutdown zone radius (m)
-------------------------------------- Level B
Activity Low-frequency harassment zone
cetaceans Phocid pinnipeds radius (m)
----------------------------------------------------------------------------------------------------------------
Single Airgun.......................................... 1,100 350 3,188
Sparker................................................ 500 N/A 447
----------------------------------------------------------------------------------------------------------------
Vessel Strike Avoidance
Crew and supply vessel personnel should use an appropriate
reference guide that includes identifying information on all marine
mammals and other marine aquatic protected species that may be
encountered. Vessel operators must comply with the below measures
except under extraordinary circumstances when the safety of the vessel
or crew is in doubt or the safety of life at sea is in question.
<bullet> Vessel operators and crews must maintain a vigilant watch
for all protected species and slow down, stop their vessel, or alter
course, as appropriate and regardless of vessel size, to avoid striking
any protected species. A single protected species at the surface may
indicate the presence of submerged animals in the vicinity of the
vessel; therefore, precautionary measures should always be exercised. A
visual observer aboard the vessel must monitor a vessel strike
avoidance zone around the vessel (species-specific distances detailed
below). Visual observers monitoring the vessel strike avoidance zone
may be third-party observers (i.e., PSOs) or crew members, but crew
members responsible for these duties must be provided sufficient
training to (1) distinguish protected species from other phenomena and
(2) broadly to identify a marine mammal as a whale, seal, or other
marine mammals.
<bullet> Vessel speed within west Harrison Bay must generally be
restricted to 15 knots or less, must be reduced to 5 knots if within
300 yds (274 m) of a whale and must be reduced to 10 knots or less when
weather conditions reduce visibility to 1.6 km or less;
<bullet> All vessels must maintain a minimum separation distance of
100 m from bowhead whales. If a bowhead whale is sighted within the
relevant separation distance, and if safety allows, the vessel must
reduce speed and shift the engine to neutral. Engines must not be
engaged until the whale has moved outside of the vessel's path and
beyond 100 m (328 ft).
<bullet> All vessels must, to the maximum extent practicable,
attempt to maintain a minimum separation distance of 100 yds (91 m)
from all other marine mammals, with an understanding that at times this
may not be possible (e.g., for animals that approach the vessel), and;
<bullet> When protected species are sighted while a vessel is
underway, the vessel shall take action as necessary to avoid violating
the relevant separation distance (e.g., attempt to remain parallel to
the animal's course, avoid excessive speed or abrupt changes in
direction until the animal has left the area, reduce speed and shift
the engine to neutral). This does not apply to any vessel towing gear
or any vessel that is navigationally constrained.
Mitigation for the Sea Ice Trail Crossing the Colville River Delta
Unless otherwise noted, these measures apply to ringed seals and
the portion of the sea ice trail crossing the Colville River Delta.
Take is only expected for this section of trail because this is the
only suitable ringed seal habitat the ice trails will cross. These
mitigation measures are organized into the following categories: (1)
general mitigation measures (implemented throughout the ice trail
season, which occurs generally from December through May) and (2)
mitigation measures that begin after March 1st.
[[Page 40584]]
General Ice Trail Mitigation Measures
Ice trail mitigation measures are based on the following
assumptions: ice trail construction occurs from approximately December
1st to mid-February (or as soon as sea ice conditions allow safe access
and permit such activity); operations and maintenance generally occur
from approximately mid-January through mid- to late-May. Ringed seals
begin to establish birth lairs in late March. Therefore, ice trail
construction should be initiated no later than March 1st (i.e.,
surface-disturbing activities such as clearing or packing of snow or
grading to be completed for the full spatial extent of the ice trails
prior to March 1st) to reduce the potential for disturbance to ringed
seal birth lairs/dens; and disturbance associated with construction
prior to March 1st may deter pregnant seals from establishing birth
lairs in the disturbed areas.
The following mitigation measures will be implemented throughout
the entire ice trail season, including during construction,
maintenance, active use, and decommissioning:
<bullet> Qualified observers for ice trail monitoring activities
need not be trained PSOs, but they will have received the training
described in the Wildlife Training in this section. In addition, they
will be capable of detecting, observing, and monitoring ringed seal
presence and behaviors, and accurately and completely recording data.
<bullet> Prior to initiation of sea ice trail construction
activities, project personnel associated with ice trail construction,
maintenance, or use (i.e., construction workers, surveyors, vehicle
operators, security personnel, and the environmental team) will receive
annual training on seal avoidance mitigation measures appropriate for
the work that they will perform (e.g., ice trial maintenance). The
annual training for all such personnel will include reviewing
applicable portions of Narwhal's Wildlife Interaction Plan, which
include the following measures:
<bullet> In addition to reviewing the mitigation measures, wildlife
training for personnel involved in ice trail construction/maintenance
or seal monitoring will include:
<bullet> how to identify ringed seal adults and pups;
<bullet> seal life history;
<bullet> habitat and diet;
<bullet> presence in project area;
<bullet> importance of lairs, breathing holes, and basking;
<bullet> potential effects of disturbance; and
<bullet> applicable laws and regulatory requirements.
<bullet> Personnel shall not approach or interact with any
wildlife.
<bullet> Personnel must follow directions of Security and posted
signs when traveling the ice trail.
<bullet> Workers must notify appropriate personnel if a seal is
observed within 50 m, or if a seal structure (i.e., breathing hole or
lair) is observed within 150 m of the centerline of the ice trail.
<bullet> Workers must stay in the vehicle and continue traveling at
a constant speed if a seal is observed near the trail. Do not slow
down, stop, or exit the vehicle.
<bullet> Transport vehicles (passenger vehicles and trucks hauling
goods) will not stop within 50 m of observed seals or 150 m of known
seal lairs. Instead, they will continue travelling at a constant speed.
<bullet> Ice trail speed limits will be 45 miles per hour (72
kilometers per hour) or less, based on environmental, road conditions,
and ice trail longevity considerations.
<bullet> The coastal sea ice trail will be established with GPS
point coordinates and operators will be required to adhere to the route
during transit. Any deviation from the established route will be for
safety purposes. Delineators will mark the roadway in a minimum of \1/
4\-mile increments on both sides of the portions of ice trails in west
Harrison Bay to delineate the path of vehicle travel and areas of
planned on-ice activities (e.g., emergency response exercises).
Delineators may also be used to mark the centerline of the roadway.
<bullet> Corners of rig mats, steel plates, and other materials
used to bridge sections of hazardous ice will be clearly marked or
mapped using GPS coordinates of the locations.
<bullet> Any seal structures (i.e., breathing holes and lairs)
observed will be avoided by a minimum of 150 meters (about 500 feet)
during ice testing and new trail construction and their locations will
be reported and physically marked.
<bullet> Personnel will be instructed that approaching or
interacting with seals is prohibited.
<bullet> If a seal is observed within 50 meters (164 feet) or if a
seal structure (i.e., breathing hole or lair) is detected within 150
meters (about 500 feet) of the centerline of an ice trail, the
Narwhal's Environmental Specialist or Project Manager will be informed
of the observation, who will then carry out the notification protocol
and implement the procedures described in the Monitoring Measures for
Ice Trails section (below). The following procedures will also be
followed:
[cir] The location of the seal or seal structure will be physically
marked (e.g., at its position along the axis of the ice trail) by
placing a readily visible marker (e.g., pole and flag) within 15 meters
(50 feet) of the edge of the ice trail, while maintaining a distance of
at least 15 meters (50 feet) from the seal/seal structure.
[cir] During the period in which a seal structure is periodically
monitored as described in the Monitoring Measures for Ice Trails
section (below), maintenance work will proceed in a manner that
minimizes impacts or disturbance to the area.
Ice Trail Mitigation Measures That Begin After March 1st
After March 1st and continuing until the decommissioning of ice
trails is completed, on-ice activities can occur anywhere on sea ice
where water depth is less than 3 meters (10 feet) (i.e., habitat less
suitable for ringed seal lairs and breathing holes). However, after
March 1st on those sections of the ice trails where water depth is
greater than 3 meters (10 feet), all activities will occur within the
boundaries of the driving lane or shoulder area of the ice trail and
other previously disturbed areas (e.g., spill and emergency response
areas, snow push areas), as long as personnel safety is ensured.
<bullet> If safety concerns due to unstable ice trail conditions
warrant the creation of workaround route after March 1st, the route
will be surveyed for seal structures using a trained observer in a
tracked vehicle approximately 2 days prior to establishing the route,
weather permitting. Surveys must occur following improved weather
conditions before establishing the workaround route. The following
protocol will be used for these surveys:
[cir] During daylight hours with good visibility, a trained
wildlife observer will survey the route 2 days prior to route
construction to search for potential seal structures. The observer will
be dedicated to monitoring for seal structures while the driver
operates the tracked vehicle. Ringed seal structures will be avoided by
a minimum of 150 m during ice testing and new route construction.
[cir] If a suspected seal structure is observed within 150 m of
either edge of the proposed new or workaround route, a marker will be
placed 15 m from the location and GPS coordinates will be recorded. The
new route must avoid any suspected seal structures by a 150 m distance.
<bullet> Ice trail construction and maintenance activities will
remain at least 50 meters (164 feet) from a seal and
[[Page 40585]]
150 meters (about 500 feet) from a known seal structure (i.e.,
breathing hole or lair) except under emergency conditions when blading
or snow blowing is necessary. If snow blowing must occur within 50
meters (164 feet) of a seal or 150 meters (about 500 feet) of a seal
structure, the snow will first be pushed so that it can subsequently be
blown downwind of the animal or seal structure.
Mitigation Measures for Aircraft
<bullet> Except during takeoff and landing and in emergency
situations, all aircraft will transit at an altitude of at least 457
meters (1,500 feet) while maintaining Federal Aviation Administration
flight rules (e.g., avoidance of cloud ceiling, etc.). If flights must
occur at altitudes less than 457 meters (1,500 feet), aircraft will
make course adjustments, as needed, to maintain at least a 457 meters
(1,500 feet) horizontal separation from all observed marine mammals.
<bullet> Aircraft will not hover or circle over marine mammals.
<bullet> Aircraft will not land on ice within 1 nautical mile (1.9
kilometers) of hauled-out seals.
Mitigation for Subsistence Uses of Marine Mammals or Plan of
Cooperation
Regulations at 50 CFR 216.104(a)(12) further require IHA applicants
conducting activities in or near a traditional Arctic subsistence
hunting area and/or that may affect the availability of a species or
stock of marine mammals for Arctic subsistence uses to provide a Plan
of Cooperation (POC) or information that identifies what measures have
been taken and/or will be taken to minimize adverse effects on the
availability of marine mammals for subsistence purposes. A plan must
include the following:
<bullet> A statement that the applicant has notified and provided
the affected subsistence community with a draft plan of cooperation;
<bullet> A schedule for meeting with the affected subsistence
communities to discuss activities and to resolve potential conflicts
regarding any aspects of either the operation or the plan of
cooperation;
<bullet> A description of what measures the applicant has taken
and/or will take to ensure that activities will not interfere with
subsistence whaling or sealing; and
<bullet> What plans the applicant has to continue to meet with the
affected communities, both prior to and while conducting the activity,
to resolve conflicts and to notify the communities of any changes in
the operation.
After withdrawing its original request, Narwhal resubmitted its
application on November 1, 2024, which included a draft POC for NMFS.
The POC outlines Narwhal's extensive coordination with subsistence
communities that may be affected by the oil and gas exploration
project. It includes a brief description of the project, community
outreach that has already been conducted, as well as the concerns
raised in those discussions and how they were addressed, and project
mitigation measures. Narwhal has agreed to continue coordination with
subsistence communities throughout the project duration and maintain
constant communication with subsistence groups, as described below and
in the POC. The POC is a living document and has been updated during
the IHA process. The IHA includes a requirement stating that Narwhal
must conduct the communication and coordination as described in the
POC, which is available on our website at <a href="https://www.fisheries.noaa.gov/national/marine-mammal-protection/incidental-take-authorizations-other-energy-activities-renewable">https://www.fisheries.noaa.gov/national/marine-mammal-protection/incidental-take-authorizations-other-energy-activities-renewable</a>.
Narwhal continues to document its communications with the North
Slope subsistence communities, as well as the substance of its
communications with subsistence stakeholder groups, and Narwhal will
continue to routinely engage with local communities and subsistence
groups. Multiple user groups are often consulted simultaneously as part
of larger coalition meetings such as the AEWC and Ice Seal Committee
meetings. Local communities and subsistence groups identified by
Narwhal are listed in Section 5 of the POC. Narwhal has developed a POC
and will implement this plan before initiating construction operations
to coordinate activities with local subsistence users and stakeholders
to eliminate the risk of interfering with subsistence hunting
activities and keep current as to the timing and status of the bowhead
whale hunt and other subsistence hunts. Narwhal will utilize in-person,
video conferencing, telephonic, written, and email communication
formats depending upon stakeholder representative locations, schedule
availability, meeting location preferences and other factors. All
stakeholder engagement activities and communications will be documented
in the Narwhal Stakeholder Communication Log. The IHA requires that
Narwhal must coordinate with local subsistence communities, notify the
communities of any changes in the operation, and take action to avoid
or mitigate impacts to subsistence harvests.
The AEWC works annually with industry partners to develop a CAA.
This agreement implements mitigation measures that allow industry to
conduct their work in or transiting the vicinity of active subsistence
hunters, in areas where subsistence hunters anticipate hunting, or in
areas that are in sufficient proximity to areas expected to be used for
subsistence hunting where the planned activities could potentially
adversely affect the subsistence bowhead whale hunt through effects on
bowhead whales, while maintaining the availability of bowheads for
subsistence hunters. Narwhal has stated that they will enter the CAA
for the project year.
Narwhal will continue to coordinate with Alaska Native villages and
subsistence organizations to identify and avoid potential impacts to
subsistence hunting.
As described in the Effects of Specified Activities on Subsistence
Uses of Marine Mammals section of the proposed IHA, Narwhals activities
do not overlap with the areas where subsistence hunters typically
harvest ice seals and given the extent of impacts to seals described in
that section, these activities are not expected to impact subsistence
hunts of ice seals. Therefore, NMFS does not propose to include
mitigation measures for subsistence harvest of ice seals; however,
Narwhal will continue to meet with subsistence groups, including the
Ice Seal Committee, as described in its POC.
NMFS conducted an independent evaluation of the proposed measures,
and 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 uses.
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
[[Page 40586]]
most value is obtained from the required monitoring.
Monitoring and reporting requirements prescribed by NMFS should
contribute to improved understanding of one or more of the following:
<bullet> Occurrence of marine mammal species or stocks in the area
in which take is anticipated (e.g., presence, abundance, distribution,
density);
<bullet> Nature, scope, or context of likely marine mammal exposure
to potential stressors/impacts (individual or cumulative, acute or
chronic), through better understanding of: (1) action or environment
(e.g., source characterization, propagation, ambient noise); (2)
affected species (e.g., life history, dive patterns); (3) co-occurrence
of marine mammal species with the activity; or (4) biological or
behavioral context of exposure (e.g., age, calving or feeding areas);
<bullet> Individual marine mammal responses (behavioral or
physiological) to acoustic stressors (acute, chronic, or cumulative),
other stressors, or cumulative impacts from multiple stressors;
<bullet> How anticipated responses to stressors impact either: (1)
long-term fitness and survival of individual marine mammals; or (2)
populations, species, or stocks;
<bullet> Effects on marine mammal habitat (e.g., marine mammal prey
species, acoustic habitat, or other important physical components of
marine mammal habitat); and,
<bullet> Mitigation and monitoring effectiveness.
<bullet> The monitoring and reporting requirements described in the
following were proposed by Narwhal in its adequate and complete
application and/or are the result of subsequent coordination between
NMFS and Narwhal. Narwhal has agreed to the requirements. NMFS
describes these below as requirements and has included them in the IHA.
PSO Requirements for Shallow Water Hazard Surveys
Vessel-Based Visual Monitoring
As described above, PSO observations will take place during daytime
airgun operations. During shallow water hazard survey operations, two
visual PSOs will be on duty at all times during daytime hours. Narwhal
will provide the lead PSO and all other PSOs the equipment (including
backup equipment) needed to adequately perform necessary tasks,
including accurate determination of distance and bearing to observed
marine mammals. Narwhal must use a dedicated, trained, and NMFS-
approved lead PSO. Additional PSOs may be Narwhal staff members that
are trained by the lead PSO, and they must have no other assigned tasks
during monitoring periods other than to conduct observational effort,
collect data, and communicate with and instruct relevant vessel crew
(including brief alerts regarding maritime hazards). At least one
visual PSO aboard the vessel must have a minimum of 90 days at-sea
experience working in those roles, respectively, with no more than 18
months elapsed since the conclusion of the at-sea experience. One
visual PSO with such experience shall be designated as the lead for the
entire protected species observation team. The lead PSO shall serve as
primary point of contact for the vessel operator and ensure all PSO
requirements per the IHA are met. To the maximum extent practicable,
the experienced PSOs should be scheduled to be on duty with those PSOs
with appropriate training but who have not yet gained relevant
experience. The PSOs must have no tasks other than to conduct
observational effort, record observational data, and communicate with
and instruct relevant vessel crew with regard to the presence of marine
mammals and mitigation requirements. The lead PSO resume shall be
provided to NMFS for approval. Monitoring shall be conducted in
accordance with the following requirements:
<bullet> PSOs shall have successfully completed an approved PSO
training course appropriate for their designated task.
<bullet> NMFS must review and approve PSO resumes accompanied by a
relevant training course information packet that includes the name and
qualifications (i.e., experience, training completed, or educational
background) of the instructor(s), the course outline or syllabus, and
course reference material as well as a document stating successful
completion of the course.
<bullet> PSOs must successfully complete relevant training,
including completion of all required coursework and passing (80 percent
or greater) a written and/or oral examination developed for the
training program.
<bullet> PSOs must have successfully attained a bachelor's degree
from an accredited college or university with a major in one of the
natural sciences, a minimum of 30 semester hours or equivalent in the
biological sciences, and at least one undergraduate course in math or
statistics.
<bullet> The educational requirements may be waived if the PSO has
acquired the relevant skills through alternate experience. Requests for
such a waiver shall be submitted to NMFS and must include written
justification. Requests shall be granted or denied (with justification)
by NMFS within 1 week of receipt of submitted information. Alternate
experience that may be considered includes, but is not limited to (1)
secondary education and/or experience comparable to PSO duties; (2)
previous work experience conducting academic, commercial, or
government-sponsored protected species surveys; (3) previous work
experience as a PSO; the PSO should demonstrate good standing and
consistently good performance of PSO duties; or (4) PSOs may also
substitute Alaska native traditional knowledge for experience.
Monitoring for Shallow Water Hazard Surveys
During the operation of the single airgun, one PSO will conduct
monitoring duties from the source vessel and a second PSO will conduct
monitoring from a support vessel. PSOs must record all observations of
marine mammals, regardless of distance from the single airgun or
sparker, as well as the additional data as required in the reporting
requirements.
Monitoring During Ice Trail Construction and Operation
If a seal is observed within 50 meters (164 feet) or if a seal
structure (i.e., breathing hole or lair) is observed within 150 meters
(about 500 feet) of the centerline of the ice trail the location of the
seal or seal structure will be reported to the Environmental Specialist
or Project Manager, who will then relay the observation location
information to all personnel using the ice trail.
<bullet> As soon as practicable after the initial seal observation,
the Environmental Specialist or qualified observer will observe the
seal for approximately 15 minutes to document the animal's location
relative to the trail.
<bullet> Qualified observers for ice trail monitoring activities
need not be trained PSOs, but they will have received the training
described in the sea ice trails observer/environmental specialist
requirements section above. In addition, they will be capable of
detecting, observing, and monitoring ringed seal presence and
behaviors, and accurately and completely recording data.
<bullet> All work that is occurring when the seal is observed and
the behavior of the seal during this observation period will be
documented for an initial 15-minute observation period and every 6
hours thereafter during daylight hours (during
[[Page 40587]]
active use of the route) until the animal moves more than 50 meters
(164 feet) from the center of the road/trail or is no longer observed.
<bullet> If a ringed seal breathing hole or lair is observed within
150 m of the sea ice trail within the Colville River Delta, the
location of the structure will be documented to the extent possible
from the sea ice trail using GPS and reported to the Narwhal Permitting
and Compliance Manager.
[cir] At least one ATV driver from a traveling group will monitor
the breathing hole/lair from the trail for 15 minutes in daylight
conditions on the day of the initial sighting to determine whether a
ringed seal is present; and
[cir] Observations by an ATV driver for a seal near the breathing
hole/lair will occur for 15 minutes each day while the trail is
traveled unless it is determined the structure is not actively being
used (i.e., a seal is not sighted at that location during monitoring).
Monitoring measures that begin after March 1st:
<bullet> If an ice trail is being actively used, under daylight
conditions with good visibility, a dedicated observer (not the vehicle
operator) must conduct a survey along the sea ice trail to observe if
any ringed seals are within 150 m (500 ft) of the roadway corridor. The
following survey protocol must be implemented:
[cir] Surveys will be conducted every 3 days during daylight hours.
Survey protocol consists of driving the ice trail and stopping every
\1/2\ mile to observe the area within 150 meters (about 500 feet) of
the roadway corridor for approximately 5 minutes on each side of the
corridor to check for the presence of seals or structures.
[cir] When performing observations, qualified observers will have
no other primary duty than to watch for and report observations related
to ringed seals during this survey. If the observer is driving a
vehicle, then the survey will be performed when the driver stops, at
periodic intervals sufficient to complete a thorough assessment of the
area, given visibility conditions. If weather conditions become unsafe,
the monitoring activity will be discontinued.
Narwhal will engage subsistence hunters for monitoring
recommendations:
<bullet> Narwhal will engage local hunters through the Ice Seal
Committee point of contact to gather recommendations on methods for
ringed seal detection within the exposure areas along the Colville
River Delta; and
<bullet> Narwhal will incorporate recommendations, as appropriate,
into training materials provided to personnel responsible for
monitoring for ringed seals along the sea ice trail.
Narwhal is required to submit a draft report on all monitoring
conducted under the IHA within 90 calendar days of the completion of
marine mammal monitoring or 60 days prior to the issuance of any
subsequent IHA for this project, whichever comes first. A final report
shall be prepared and submitted within 30 days following resolution of
comments on the draft report from NMFS. This report shall include:
For Shallow Water Hazard Surveys:
For data collection purposes, PSOs must use standardized electronic
data collection forms. PSOs shall record detailed information about any
implementation of mitigation requirements, including the distance of
animals to the airgun array and description of specific actions that
ensued, the behavior of the animal(s), any observed changes in behavior
before and after implementation of mitigation, and if shutdown was
implemented, the length of time before any subsequent ramp-up of the
airgun array. If required mitigation was not implemented, PSOs should
record a description of the circumstances. At a minimum, the following
information must be recorded:
[cir] Vessel name, vessel size and type, maximum speed capability
of vessel;
[cir] Dates (MM/DD/YYYY) of departures and returns to port with
port name;
[cir] PSO names and affiliations, PSO identification (initials or
other identifier);
[cir] Date (MM/DD/YYYY) and participants of PSO briefings;
[cir] Visual monitoring equipment used (description);
[cir] PSO location on vessel and height (meters) of observation
location above water surface;
[cir] Watch status (description);
[cir] Dates (MM/DD/YYYY) and times (Greenwich Mean Time (GMC)/
Coordinated Universal Time (UTC)) of survey on/off effort and times
(GMC/UTC) corresponding with PSO on/off effort;
[cir] Vessel location (decimal degrees) when survey effort began
and ended and vessel location at beginning and end of visual PSO duty
shifts;
[cir] Vessel location (decimal degrees) at 30-second intervals if
obtainable from data collection software, otherwise at practical
regular interval;
[cir] Vessel heading (compass heading) and speed (knots) at
beginning and end of visual PSO duty shifts and upon any change;
[cir] Water depth (meters) (if obtainable from data collection
software);
[cir] Environmental conditions while on visual survey (at beginning
and end of PSO shift and whenever conditions changed significantly),
including BSS and any other relevant weather conditions including cloud
cover, fog, sun glare, and overall visibility to the horizon;
[cir] Factors that may have contributed to impaired observations
during each PSO shift change or as needed as environmental conditions
changed (description) (e.g., vessel traffic, equipment malfunctions);
and
[cir] Vessel/Survey activity information (and changes thereof)
(description), such as airgun power output while in operation, number
and volume of airguns operating in the array, tow depth of the array,
and any other notes of significance (i.e., pre-start clearance, ramp-
up, shutdown, testing, shooting, ramp-up completion, end of operations,
streamers, etc.).
<bullet> Upon visual observation of any marine mammals, the
following information must be recorded:
[cir] Sighting ID (numeric);
[cir] Watch status (sighting made by PSO on/off effort,
opportunistic, crew, alternate vessel/platform);
[cir] Location of PSO/observer (description);
[cir] Vessel activity at the time of the sighting (e.g., deploying,
recovering, testing, shooting, data acquisition, other);
[cir] PSO who sighted the animal/ID;
[cir] Time/date of sighting (GMT/UTC, MM/DD/YYYY);
[cir] Initial detection method (description);
[cir] Sighting cue (description);
[cir] Vessel location at time of sighting (decimal degrees);
[cir] Water depth (meters);
[cir] Direction of vessel's travel (compass direction);
[cir] Speed (knots) of the vessel from which the observation was
made;
[cir] Direction of animal's travel relative to the vessel
(description, compass heading);
[cir] Bearing to sighting (degrees);
[cir] Identification of the animal (e.g., genus/species, lowest
possible taxonomic level, or unidentified) and the composition of the
group if there is a mix of species;
[cir] Species reliability (an indicator of confidence in
identification) (1 = unsure/possible, 2 = probable, 3 = definite/sure,
9 = unknown/not recorded);
[cir] Estimated distance to the animal (meters) and method of
estimating distance;
[cir] Estimated number of animals (high/low/best) (numeric);
[cir] Estimated number of animals by cohort (adults, yearlings,
juveniles, calves, group composition, etc.);
[[Page 40588]]
[cir] Description (as many distinguishing features as possible of
each individual seen, including length, shape, color, pattern, scars or
markings, shape and size of dorsal fin, shape of head, and blow
characteristics);
[cir] Detailed behavior observations (e.g., number of blows/
breaths, number of surfaces, breaching, spyhopping, diving, feeding,
traveling; as explicit and detailed as possible; note any observed
changes in behavior);
[cir] Animal's closest point of approach (meters) and/or closest
distance from any element of the airgun array;
[cir] Description of any actions implemented in response to the
sighting (e.g., delays, shutdown, ramp-up) and time and location of the
action;
[cir] Photos (Yes/No);
[cir] Photo Frame Numbers (List of numbers); and
[cir] Conditions at time of sighting (Visibility; BSS).
For Ice Trails:
<bullet> Date and time of each observation event (e.g., initial
observation of a seal or seal structure) and subsequent monitoring;
<bullet> Environmental conditions during each observation event;
<bullet> Number of animals per observation event; and number of
adults/juveniles/pups per observation event;
<bullet> Behaviors of seals during each observation event;
<bullet> Geographic coordinates of the observed animals or
structure (breathing hole or lair), with the position recorded by using
the most precise coordinates practicable (coordinates will be recorded
in decimal degrees, or similar standard, and defined coordinate
system); and
<bullet> Distance of seals and seal structures from the centerline
of the ice trail.
Reporting Dead or Injured Marine Mammals--In the event that
personnel involved in the project activities covered by the
authorization discover an injured or dead marine mammal, the IHA-holder
shall report the incident to the Office of Protected Resources (OPR),
NMFS (<a href="/cdn-cgi/l/email-protection#28787a06617c7806654746415c475a41464f7a4d58475a5c5b6846474949064f475e"><span class="__cf_email__" data-cfemail="5000027e1904007e1d3f3e39243f22393e370235203f222423103e3f31317e373f26">[email protected]</span></a> and <a href="/cdn-cgi/l/email-protection#0c45585c226f636f677e6960604c62636d6d226b637a"><span class="__cf_email__" data-cfemail="ade4f9fd83cec2cec6dfc8c1c1edc3c2cccc83cac2db">[email protected]</span></a>) and
to the Alaska regional stranding coordinator (907-586-7209) as soon as
feasible. The report must include the following information:
<bullet> Time, date, and location (latitude/longitude) of the first
discovery (and updated location information if known and applicable);
<bullet> Species identification (if known) or description of the
animal(s) involved;
<bullet> Condition of the animal(s) (including carcass condition if
the animal is dead);
<bullet> Observed behaviors of the animal(s), if alive;
<bullet> If available, photographs or video footage of the
animal(s); and
<bullet> General circumstances under which the animal was
discovered.
Vessel Strike--In the event of a strike of a marine mammal by any
vessel involved in the activities covered by the authorization, Narwhal
shall report the incident to OPR, NMFS, and the Alaska regional
stranding coordinator (907-586-7209) as soon as feasible. The report
must include the following information:
<bullet> Time, date, and location (latitude/longitude) of the
incident;
<bullet> Vessel's speed during and leading up to the incident;
<bullet> Vessel's course/heading and what operations were being
conducted (if applicable);
<bullet> Status of all sound sources in use;
<bullet> Description of avoidance measures/requirements that were
in place at the time of the strike and what additional measure were
taken, if any, to avoid strike;
<bullet> Environmental conditions (e.g., wind speed and direction,
BSS, cloud cover, visibility) immediately preceding the strike;
<bullet> Species identification (if known) or description of the
animal(s) involved;
<bullet> Estimated size and length of the animal that was struck;
<bullet> Description of the behavior of the marine mammal
immediately preceding and following the strike;
<bullet> If available, description of the presence and behavior of
any other marine mammals present immediately preceding the strike;
<bullet> Estimated fate of the animal (e.g., dead, injured but
alive, injured and moving, blood or tissue observed in the water,
status unknown, disappeared); and
<bullet> To the extent practicable, photographs or video footage of
the animal(s).
Monitoring Plan Peer Review
The MMPA requires that monitoring plans be independently peer
reviewed where the proposed activity may affect the availability of a
species or stock for taking for subsistence uses (16 U.S.C.
1371(a)(5)(D)(ii)(III)). Regarding this requirement, NMFS' implementing
regulations state that upon receipt of a complete monitoring plan and
at its discretion, NMFS will either submit the plan to members of a
peer review panel for review or within 60 days of receipt of the
proposed monitoring plan, schedule a workshop to review the plan (50
CFR 216.108(d)).
NMFS established an independent PRP to review the Monitoring
Measures in Narwhal's application in April 2025. NMFS provided the
panel with a copy of Narwhal's application and a list of considerations
to guide their discussion of the monitoring plan. The panel provided a
final report to NMFS on May 2, 2025 containing recommendations for
Narwhal's monitoring plan. The PRP's primary recommendations and
comments are summarized and addressed below. The PRP's full report is
posted on NMFS' website at: <a href="https://www.fisheries.noaa.gov/action/incidental-take-authorization-narwhal-llcs-oil-and-gas-exploration-activities-west-harrison">https://www.fisheries.noaa.gov/action/incidental-take-authorization-narwhal-llcs-oil-and-gas-exploration-activities-west-harrison</a>.
Recommendation 1.2.1
The PRP recommended that the PSO team consist of one lead PSO
(biologist) and strongly advised that Narwhal have at least one
I[ntilde]upiat observer and that the lead PSO have at least one year of
prior PSO experience, preferably on projects in Arctic Alaska. Given
the extensive traditional knowledge of local I[ntilde]upiat on marine
mammals and their behavior, the inclusion of a local I[ntilde]upiat
Observer will enhance the monitoring data. Based on the requirement in
the MMPA to avoid unmitigable adverse impacts on the availability of
marine mammals for subsistence use, the PRP stated that presence of the
local I[ntilde]upiat Observer will enable the vessel to be better
informed of subsistence activities in the area and will facilitate
communications with subsistence hunters in the area. Narwhal plans to
have one third-party observer onboard as a lead PSO as outlined in the
PSO requirements of the IHA. Narwhal will source an I[ntilde]upiat
observer to the best of its ability.
The lead PSO will be stationed directly on the source vessel and
will be responsible for monitoring the shutdown zone and for
communications with the project manager when implementation of
mitigation measures is necessary. The lead PSO will also oversee and
coordinate the other PSOs. The PRP recommended that given the
likelihood of 24-hour operations in the summer, the PRP understands
that at least four PSOs will be needed during seismic activities. While
Narwhal notes that 24-hour operations are not planned, Narwhal has
agreed to the PSO shift limitations in the IHA and will provide
sufficient PSO staffing, in addition to the independent lead PSO, to
carry out the monitoring duties.
The PRP also recommended that NMFS require Narwhal to abide by its
most recent PSO qualification requirements. The PRP recommended that
NMFS make it clear to Narwhal that vessel crew are not to be used as
PSOs. Only experienced NMFS-qualified PSOs
[[Page 40589]]
and local I[ntilde]upiat Observers should be used to satisfy the
observer requirements. The PRP further recommended that, if bunk space
is limited, Narwhal should consider use of a third vessel for the PSOs
and local I[ntilde]upiat Observers during the shallow hazard survey.
The PRP stated that a third vessel will provide ample bunk space for
the appropriate number of observers to effectively monitor the zone
during this activity. Narwhal has requested the use of trained staff,
under the supervision of an independent lead PSO, as the other
qualified PSOs given the limited berthing capacity of the survey
vessels used in the shallow water hazard survey. Currently only two
vessels are planned for use in the survey and the placement of a third
vessel will increase vessel traffic in the area and it is logistically
not feasible.
NMFS is requiring that the lead PSO be a third-party independent
observer as recommended by the PRP. The PRP's recommendation for all
PSOs to be independent third-party observers is not practicable given
the reasons described above, and therefore, NMFS has not included this
recommendation in the final IHA.
Recommendation 1.2.2
The first two PRP recommendations in this section were related to
mitigation measures. First the PRP recommended that Narwhal should be
required to complete all of the seismic activities prior to August 25,
2025, to avoid impacts to migrating bowhead whales. The second
recommendation was that staging of equipment for activities be
completed as early as possible to reduce vessel traffic during the fall
migration and hunt. NMFS responded to these recommendations in the
Comments and Response section of this notice. Please see Comments 3 and
4 for NMFS response to these recommendations.
The PRP also stressed its opinion that communication with local
subsistence hunters will be key to preventing unmitigable adverse
impacts on subsistence use, as required by the MMPA. The PRP
recommended that Narwhal be required to engage in daily communication
with subsistence whaling crews and other marine mammal subsistence
hunters to ensure that adverse impacts on subsistence hunting are
avoided or minimized.
Narwhal has agreed to engage in daily communication with
subsistence whaling crews and other marine mammal subsistence hunters
as outlined in the CCA signed by Narwhal on July 7, 2025.
Recommendation 1.2.3
The PRP noted that Narwhal did not specify in the monitoring plan
what methods it plans to use to detect sea lairs (e.g., opportunistic
ground-based sightings, trained dogs, aerial surveys, infrared aerial
sensors). Further the PRP stated that it is prudent that Narwhal be
able to detect ringed seal lairs effectively, as ice trail construction
activities have the potential to result in injuries or mortalities of
ringed seals that occupy lairs that have gone undetected in close
proximity to those activities. Therefore, the PRP recommends that
Narwhal be required to (1) engage local hunters through the Ice Seal
Committee point of contact to gather recommendations on methods for
ringed seal and lair detection along sea ice roads/trails within the
exposure areas, (2) incorporate the Committee's recommendations into
Narwhal's training materials provided to personnel responsible for
monitoring for ringed seals and lairs along sea ice roads/trails, and
(3) include the methods used for detection of seals and lairs in the
final report.
Narwhal has agreed to implement all of these recommendations from
the PRP and Narwhal has agreed to include the methods for detection for
all seal structures including breathing holes in its final report. This
reporting requirement is included in the final IHA.
Recommendations 1.2.4, 1.2.5, and 1.2.6
These recommendations were mitigation-focused, rather than
monitoring-focused. Therefore, NMFS has responded to these
recommendations as public comments. Recommendation 1.2.4 was already
included as a mitigation measure in the proposed IHA and is not part of
the Comment and Response Section of this notice. Please see Comment 2
in the Comments and Responses section of this notice for responses to
1.2.5. Recommendation 1.2.6 regarding the use of inland community
trails and awareness of associated wildlife such as caribou and polar
bears. These species are managed by USFWS, rather than NMFS. NMFS has
passed along the recommendation to USFWS.
Recommendation 1.2.7
The PRP recommended that Narwhal include communications with
Whaling Captains Associations of Barrow, Native Villages of Barrow,
Kuukpik Corporation, Inupiat Community of the Arctic Slope, Alaska
Nannut Co-Management Council, and the Beluga Whale Committee as part of
their POC. The panel urged Narwhal to meet with these communities and
provide a summary of the concerns that were shared and what measures
Narwhal intends to incorporate in its plans to address these concerns
and updates reflected in the final monitoring plan.
Narwhal has agreed to reach out to all of the organizations the PRP
recommended and update the POC with the concerns raised at those
meetings and how Narwhal intends to address those concerns. Since the
PRP meeting Narwhal has updated their POC with meetings including the
Beluga Whale Committee and the Nuiqsut City Council.
Recommendation 1.2.8
The PRP recommended that Narwhal report the estimated distance to
each observed seal structure and seal observed during the construction
and operation of the ice trails. The PRP also requested that NMFS
provide the 90-day report submitted by Narwhal to review for use in
future monitoring plan reviews by the PRP. Narwhal has agreed to
include the estimated distance of seals and seal structures in its
final report, and this requirement has been added to the final IHA.
NMFS will provide a copy of the final, approved 90-day report to
the PRP.
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
[[Page 40590]]
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 10, given that many of the anticipated
effects of the specified activities 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.
The shallow water hazard survey (single seismic airgun and sparker)
and the construction and operation of coastal sea ice trails have the
potential to disturb or temporarily displace marine mammals.
Specifically, the specified activities may result in take, in the form
of Level B harassment only, from use of the acoustic source during
shallow water hazard surveys or through disturbance incidental to the
construction and operation of coastal sea ice trails. No mortality or
serious injury is anticipated given the nature of the activity. The
potential for Level A harassment from the shallow water hazard survey
is minimized through the implementation of the required mitigation
measures (see Mitigation Measures section). The applicant will
implement shutdowns of acoustic sources during the shallow water hazard
survey before marine mammals enter the Level A harassment zones. Take
by Level A harassment is not expected during the construction and
operation of the sea ice trails.
The shallow water hazard survey has the potential to overlap with
bowhead whale Biological Important Areas (BIAs) identified as important
for feeding and migration. Three of the four BIAs (Alaska Beaufort
Parent, Harrison Bay Child, and West Alaska Beaufort Child) for feeding
occur for the months of August and September (during the shallow water
hazard survey) and are of moderate to high importance and intensity
with high data support and boundary certainty. Only a very small
portion of the shoreward boundary of the three feeding BIAs will
overlap with the project area and only 12 days of active acoustic
sources during the shallow water hazard surveys will occur. The
relative size and timing of remaining available feeding habitat for
bowheads does not suggest the activity will result in decreased fitness
of feeding bowhead whales. One of the two migratory BIAs (Beaufort)
also occurs during August and September (during the shallow water
hazard survey) and is of high importance and intensity with high data
support and boundary certainty. Only small portions of the entire BIA
will overlap with the shallow water hazard survey when compared to the
entire available area. The shallow water hazard survey also will only
occur over 12 days, therefore reducing the potential for long-term
effects. Given the small portion of overlap and the short-term effects
of this activity, it is not expected to impact reproduction or
survivorship of any individuals using the BIAs.
As described above, the project does not overlap with critical
habitat for ringed seals or bearded seals. There are no anticipated
effects from this project on designated critical habitat for these
species. While some ice trail activities (operation and demobilization)
may occur during pupping season for ringed seals, Narwhal plans to
construct the entirety of their expected ice trails prior to March 1st
when the ringed seal pupping season begins. The additional mitigation
measures required after March 1st will mitigate any potential
disturbances to seals that are actively pupping. During the
construction of the ice trail, behavioral disturbance of ringed seals
may occur but is expected to be limited given the mitigation and
monitoring measures.
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:
<bullet> No serious injury or mortality is anticipated or
authorized;
<bullet> The anticipated incidents of Level B harassment would
consist of, at most, temporary modifications in behavior that would not
result in fitness impacts to individuals;
<bullet> The area impacted by the specified activities is very
small relative to the overall habitat ranges of all species;
<bullet> While impacts will occur within areas that are important
for feeding and migration for bowhead whales, because of the small
footprint of the activity relative to the area of these important use
areas and the scope and nature of the anticipated impacts of shallow
water hazard survey, we do not expect impacts to the reproduction or
survival of any individuals.
Based on the analysis contained herein of the likely effects of the
specified activity on marine mammals and their habitat and taking into
consideration the implementation of the monitoring and mitigation
measures, NMFS finds that the total marine mammal take from the
specified activities 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 section 101(a)(5)(D) of the MMPA for specified
activities other than military readiness activities. The MMPA does not
define small numbers and so, in practice, where estimated numbers are
available, NMFS compares the number of individuals taken to the most
appropriate estimation of abundance of the relevant species or stock in
our determination of whether an authorization is limited to small
numbers of marine mammals. When the predicted number of individuals to
be taken is fewer than one-third of the species or stock abundance, the
take is considered to be of small numbers. Additionally, other
qualitative factors may be considered in the analysis, such as the
temporal or spatial scale of the activities.
The number of takes NMFS proposes to authorize is below one-third
of the modeled abundance for all relevant populations (specifically,
take of individuals is less than 0.6 percent of the most appropriate
abundance estimate for each stock, see table 10). This is conservative
because this approach assumes all takes are of different individual
animals, which is likely not the case. Some individuals may be
encountered multiple times in a day, but PSOs will count them as
separate individuals if they cannot be identified.
Based on the analysis contained herein of the activity (including
the mitigation and monitoring measures) and the anticipated take of
marine mammals, NMFS finds that small numbers of marine mammals will 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
[[Page 40591]]
``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.
Given the nature of the activity and the required mitigation
measures, serious injury and mortality of marine mammals is not
expected to occur. Impacts to marine mammals will be limited to
temporary behavioral disturbances of seals and bowhead whales. As
described above, the required mitigation measures, such as
implementation of shutdown zones, are expected to reduce the frequency
and severity of takes of marine mammals.
Project activities could deter target species from west Harrison
Bay. However, much of the project season avoids traditional ice seal
harvest windows. (As noted in the Effects of Specified Activities on
Subsistence Uses of Marine Mammals section above, Nuiqsut residents
typically harvest ice seals in the highest numbers in June, July, and
August, and Narwhal's project will not begin until August.) While some
hunting continues throughout the early fall, we do not anticipate that
there will be impacts to seals that will make them unavailable for
subsistence hunters. As noted in the Effects of Specified Activities on
Subsistence Uses of Marine Mammals section, subsistence use of bowhead
whales is limited in this area, as it is not within the preferred and
frequented hunting areas. The authorized takes are not expected to
affect the fitness of any bowhead whales, or cause significant
deflection outside of the typical migratory path in areas where
subsistence hunts occur. Narwhal will continue to coordinate with local
communities and subsistence groups to minimize impacts of the project,
as described in the POC, which the IHA requires Narwhal to abide by.
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 Narwhal's activities.
Endangered Species Act
Section 7(a)(2) of the ESA of 1973 (ESA; 16 U.S.C. 1531 et seq.)
requires that each Federal agency ensure that any action it authorizes,
funds, or carries out is not likely to jeopardize the continued
existence of any endangered or threatened species or result in the
destruction or adverse modification of designated critical habitat. To
ensure ESA compliance for the issuance of IHAs, NMFS OPR consults
internally whenever we propose to authorize take for endangered or
threatened species, in this case with the NMFS Alaska Regional Office
(AKR).
NMFS Alaska Regional Office issued a Biological Opinion under
section 7 of the ESA on the issuance of an IHA to Narwhal under section
101(a)(5)(D) of the MMPA by the NMFS OPR. The Biological Opinion
concluded that the proposed action is not likely to jeopardize the
continued existence of bowhead whale, bearded seal (Beringia DPS), and
ringed seal (Arctic subspecies), and is not likely to destroy or
adversely modify critical habitat for those species.
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.
NMFS prepared an EA and analyzed the potential impacts to marine
mammals that would result from Narwhal's oil and gas exploration
project, and subsequently signed a Finding of No Significant Impact
(FONSI) regarding the effects of its proposed action on the human
environment. Copies of the EA and FONSI are available at <a href="https://www.fisheries.noaa.gov/action/incidental-take-authorization-narwhal-llcs-oil-and-gas-exploration-activities-west-harrison">https://www.fisheries.noaa.gov/action/incidental-take-authorization-narwhal-llcs-oil-and-gas-exploration-activities-west-harrison</a>.
Authorization
NMFS has issued an IHA to Narwhal for the potential harassment of
small numbers of four marine mammal stocks incidental to the oil and
gas exploration activities in west Harrison Bay, Alaska.
Dated: August 15, 2025.
Kimberly Damon-Randall,
Director, Office of Protected Resources, National Marine Fisheries
Service.
[FR Doc. 2025-15863 Filed 8-19-25; 8:45 am]
BILLING CODE 3510-22-P
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