Rule2026-03375
Takes of Marine Mammals Incidental to Specified Activities; Taking Marine Mammals Incidental to Hilcorp Alaska, LLC Oil and Gas Activities in Cook Inlet, 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
February 20, 2026
Effective
February 20, 2026
Issuing agencies
Commerce DepartmentNational Oceanic and Atmospheric Administration
Abstract
NMFS, upon request from Hilcorp Alaska, LLC (Hilcorp), issues this final rule pursuant to the Marine Mammal Protection Act (MMPA), to govern the taking of marine mammals incidental to specified activities conducted in support of oil and gas exploration, development, production, and decommissioning in Cook Inlet, Alaska, over the course of 5 years (2026-2031) and an associated letter of authorization (LOA). Together, the final rule and LOA allow for the incidental take of marine mammals during the described specified activities and timeframes, prescribes the permissible methods of taking and other means of effecting the least practicable adverse impact on marine mammal species and their habitat, and establishes requirements pertaining to the monitoring and reporting of such taking.
Full Text
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<title>Federal Register, Volume 91 Issue 34 (Friday, February 20, 2026)</title>
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[Federal Register Volume 91, Number 34 (Friday, February 20, 2026)]
[Rules and Regulations]
[Pages 8123-8144]
From the Federal Register Online via the Government Publishing Office [<a href="http://www.gpo.gov">www.gpo.gov</a>]
[FR Doc No: 2026-03375]
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DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
50 CFR Part 217
[Docket No. 260213-0047]
RIN 0648-BN57
Takes of Marine Mammals Incidental to Specified Activities;
Taking Marine Mammals Incidental to Hilcorp Alaska, LLC Oil and Gas
Activities in Cook Inlet, Alaska
AGENCY: National Marine Fisheries Service (NMFS), National Oceanic and
Atmospheric Administration (NOAA), Commerce.
ACTION: Final rule; notification of issuance of Letter of Authorization
(LOA).
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SUMMARY: NMFS, upon request from Hilcorp Alaska, LLC (Hilcorp), issues
this final rule pursuant to the Marine Mammal Protection Act (MMPA), to
govern the taking of marine mammals incidental to specified activities
conducted in support of oil and gas exploration, development,
production, and decommissioning in Cook Inlet, Alaska, over the course
of 5 years (2026-2031) and an associated letter of authorization (LOA).
Together, the final rule and LOA allow for the incidental take of
marine mammals during the described specified activities and
timeframes, prescribes the permissible methods of taking and other
means of effecting the least practicable adverse impact on marine
mammal species and their habitat, and establishes requirements
pertaining to the monitoring and reporting of such taking.
DATES: This final rule and the LOA are effective February 20, 2026,
through February 19, 2031.
ADDRESSES: Electronic copies of the application and supporting
documents, as well as a list of the references cited in this document,
may be obtained online at: <a href="https://www.fisheries.noaa.gov/national/marine-mammal-protection/incidental-take-authorizations-oil-and-gas">https://www.fisheries.noaa.gov/national/marine-mammal-protection/incidental-take-authorizations-oil-and-gas</a>. In
case of problems accessing these documents, please call the contact
listed below.
FOR FURTHER INFORMATION CONTACT: Jaclyn Daly, Office of Protected
Resources, NMFS, (301) 427-8401.
SUPPLEMENTARY INFORMATION:
Background
The MMPA prohibits the ``take'' of marine mammals, with certain
exceptions. Sections 101(a)(5)(A) and (D) of the MMPA (16 U.S.C. 1361
et seq.) direct the Secretary of Commerce (as delegated to NMFS) to
allow, upon request, the incidental, but not intentional, taking of
small numbers of marine mammals by U.S. citizens who engage in a
specified activity (other than commercial fishing) within a specified
geographical region if certain findings are made and either regulations
are promulgated and a LOA is issued or an incidental harassment
authorization (IHA) is issued.
The statute also requires that authorization for incidental takings
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). If such findings are made, 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
[[Page 8124]]
the species or stocks for taking for certain subsistence uses (referred
to in shorthand as ``mitigation''); and set forth requirements
pertaining to the monitoring and reporting of the takings. The
definitions of applicable MMPA statutory terms are provided directly
below or included in the relevant sections of this rule.
<bullet> U.S. citizen--individual U.S. citizens or any corporation
or similar entity if it is organized under the laws of the United
States or any governmental unit defined in 16 U.S.C. 1362(13); 50 CFR
216.103);
<bullet> Take--to harass, hunt, capture, or kill, or attempt to
harass, hunt, capture, or kill any marine mammal (16 U.S.C. 1362(13);
<bullet> Incidental harassment, incidental taking, and incidental,
but not intentional, taking--an accidental taking. This does not mean
that the taking is unexpected, but rather it includes those takings
that are infrequent, unavoidable or accidental (50 CFR 216.103);
<bullet> Level A harassment--any act of pursuit, torment, or
annoyance which has the potential to injure a marine mammal or marine
mammal stock in the wild (16 U.S.C. 1362(18); 50 CFR 216.3); and
<bullet> Level B harassment--any act of pursuit, torment, or
annoyance which 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 (16 U.S.C. 1362(18); 50 CFR 216.3).
Purpose of Regulatory Action
NMFS received an application from Hilcorp requesting 5-year
regulations and a LOA that would authorize the take of 12 marine mammal
species, comprising 15 stocks, by Level B harassment, and take by Level
A harassment of 9 of those 12 species, comprising 12 stocks, incidental
to activities conducted by Hilcorp in support of oil and gas
exploration, development, production, and decommissioning. No serious
injury or mortality is anticipated or authorized.
The regulations provide a framework for authorizing the take of
marine mammals incidental to specified activities associated with
Hilcorp's oil and gas exploration, development, production, and
decommissioning activities in Cook Inlet, Alaska. NMFS has, in
accordance with the MMPA, issued the associated LOA.
Legal Authority for the Action
Section 101(a)(5)(A) of the MMPA (16 U.S.C. 1371(a)(5)(A)) 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
for up to 5 years if, after notice and public comment, the agency makes
certain findings and promulgates regulations that set forth permissible
methods of taking pursuant to that activity and other means of
effecting the ``least practicable adverse impact'' on the affected
species or stocks and their habitat (see the discussion below in the
Mitigation section), as well as monitoring and reporting requirements.
Section 101(a)(5)(A) of the MMPA and the implementing regulations at 50
CFR part 216, subpart I provide the legal basis for issuing this rule
containing 5-year regulations and the LOA.
Summary of Major Provisions Within the Rule
The major provisions of this rule are:
<bullet> Authorizing, through the issuance of the LOA, the take of
small numbers of marine mammals by Level A harassment and/or Level B
harassment incidental to Hilcorp's specified activities (no mortality
or serious injury of any marine mammal is authorized);
<bullet> Requiring operating project vessels to maintain a distance
of 2.4 km (1.5 miles) from the mean lower low water (MLLW) line of the
Susitna Delta (MLLW line between the Little Susitna River and Beluga
River) between April 15 and November 15 and restrict pile driving to
November 15 through April 15 to avoid and minimize impacts when Cook
Inlet beluga whales (CIBWs) are more likely engaging in foraging
behavior;
<bullet> Requiring NMFS-approved protected species observers (PSOs)
on board vessels associated with the specified activities and delaying
commencement of or shutting down certain activities should a marine
mammal be detected within identified clearance or shutdown zones to
minimize the amount and severity of take;
<bullet> Requiring a soft start for impact pile driving to allow
marine mammals the opportunity to leave the area prior to being exposed
to higher noise levels; and
<bullet> Requiring submission of monitoring reports including, but
not limited to, a summary of marine mammal species and behavioral
observations, construction shutdowns or delays, and construction work
completed.
Summary of Request
On October 30, 2024, NMFS received an application from Hilcorp
requesting authorization to take marine mammals incidental to oil and
gas exploration, development, production, and decommissioning
activities in Cook Inlet, Alaska. Specifically, Hilcorp plans to
conduct necessary work, including use of tugs towing, holding, or
positioning a jack-up rig; pile driving; and pipeline replacement/
installation activities. The exposure of marine mammals occurring in
the vicinity to underwater noise generated by the activities could
result in incidental take of marine mammals by Level A and/or Level B
harassment. Therefore, Hilcorp requested authorization to incidentally
take marine mammals. NMFS requested additional information from Hilcorp
regarding their request on November 19, 2024, which Hilcorp provided on
January 2, 2025. A final request from NMFS for information was sent to
Hilcorp on January 22, 2025. Hilcorp provided all necessary information
on February 10, 2025, and NMFS deemed Hilcorp's application, which
includes a Marine Mammal Monitoring and Mitigation Plan in Appendix A,
adequate and complete on February 18, 2025 (note that NMFS' Notice of
Receipt (NOR) of Hilcorp's application erroneously described this date
as being February 10, 2025). On March 13, 2025, NMFS published a NOR of
Hilcorp's adequate and complete application in the Federal Register (90
FR 11951), requesting comments and soliciting information related to
Hilcorp's request during a 30-day public comment period. NMFS did not
receive any public comments. Subsequently, on March 14, 2025, Hilcorp
submitted a revised application that corrected minor details but did
not substantively modify the description of the specified activities or
the type or amount of take requested incidental to those activities.
This revised application is available at: <a href="https://www.fisheries.noaa.gov/action/incidental-take-authorization-hilcorp-alaska-llcs-oil-and-gas-activities-cook-inlet-alaska">https://www.fisheries.noaa.gov/action/incidental-take-authorization-hilcorp-alaska-llcs-oil-and-gas-activities-cook-inlet-alaska</a>.
On July 24, 2025, NMFS published a proposed rule in the Federal
Register (90 FR 34974). The public comment period on the proposed rule
was open for 30 days from July 24, 2025 through August 25, 2025. A
summary of public comments received during this 30-day period are
described in the Comments and Responses section of this final rule;
full public comments may be viewed on <a href="https://Regulations.gov">https://Regulations.gov</a>.
[[Page 8125]]
A history of previous incidental take authorizations that NMFS has
issued to Hilcorp for identical or similar specified activities can be
found in the proposed rule (90 FR at 34975). Hilcorp complied with all
the requirements (e.g., mitigation, monitoring, and reporting) of the
previous LOAs and IHAs, and information regarding their monitoring
results may be found in the Potential Effects of Specified Activities
on Marine Mammals and their Habitat section of the proposed rule.
Description of Proposed Activity
Overview
Hilcorp plans to continue oil and gas exploration, development,
production, and decommissioning activities in Cook Inlet, Alaska, for
the reasonably foreseeable future. Over the course of the 5-year
effective period of the regulations, this work includes up to 54 days
of tugs towing, holding, or positioning a jack-up rig in support of
production drilling at existing platforms in middle Cook Inlet and
Trading Bay; up to 70 days of pile driving in support of production
well development at the Tyonek Platform in middle Cook Inlet; up to 6
days of tugs towing, holding, or positioning a jack-up rig; up to 18
days of pile driving in support of exploration drilling at two
locations in the Middle Ground Shoal Unit in middle Cook Inlet and one
location between the Anna and Bruce platforms on the northern border of
Trading Bay; and up to 22 days of pipeline replacement/installation,
involving either pipe pulling or anchor handling or a combination of
both, at up to two locations in middle Cook Inlet and/or Trading Bay.
Hilcorp requested authorization of take by Level B harassment for 12
marine mammal species and additionally by Level A harassment for a
subset of 9 of these species.
Dates and Duration
Table 1 provides a summary of the anticipated timings and durations
for Hilcorp's planned activities; however, the schedule may shift such
that actual activities occur in different years than specified below.
Table 1--Summary of Hilcorp's Planned Activities
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Anticipated duration
Project activity Cook inlet region Seasonal timing Year(s) planned \1\ of sound-producing Anticipated sound
activity sources
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Tugs under Load with a Jack-Up Rig Middle Cook Inlet..... April-December........ Years 1, 3, and 5 12 days (2 days each: 3 to 4 tugs towing,
in support of Production Drilling. (2026 2028, 2030). 1 mobilization, 4 holding, and
location-location positioning a jack-
moves, 1 up rig.
demobilization, up
to 12 total pinning
events).
Year 2 (2027)........ 10 days (2 days each:
1 mobilization, 3
location-location
moves, 1
demobilization, up
to 10 total pinning
events).
Year 4 (2029)........ 8 days (2 days each:
1 mobilization, 2
location-location
moves, 1
demobilization, up
to 8 total pinning
events).
Pile Driving in Support of Middle Cook Inlet..... Mid-November-Mid-April Year 1-Year 5 (2026- 14 days (7 days per Impact pile driving.
Production Well Development at the 2030). pile (intermittent);
Tyonek Platform. 8 hour (hr) per day;
2 piles per year).
Tugs under Load with a Jack-Up Rig Trading Bay (between April--December....... Year 2 (2027)........ 2 days tugs under Impact pile driving,
and Pile Driving in Support of Anna and Bruce load with a jack-up 3 to 4 tugs towing,
Exploratory Drilling \2\. platforms). rig (1 location- holding, and
location move, up to positioning a jack-
2 total pinning up rig.
events); 6 days
intermittent pile
driving (1 well, 1
pile each well).
Middle Cook Inlet (MGS April-December........ Year 4 (2029)........ 4 days tugs under Impact pile driving,
Unit). load with a jack-up 3 to 4 tugs towing,
rig (2 location- holding, and
location moves, up positioning a jack-
to 4 total pinning up rig.
events); 12 days
intermittent pile
driving (2 wells, 1
pile each well).
Pipeline Replacement/Installation Middle Cook Inlet/ April--November....... Year 2 (2027)........ Scenario 1: 11 days Scenario 1: Anchor
\3\. Trading Bay. using lay barge handling.
methods. Scenario 2: Anchor
Scenario 2: 22 days handling.
using lay barge
methods (11 days per
project, 2 projects).
April-November........ Year 4 (2029)........ Scenario 1: 8 days Scenario 1: 2 tugs
using pipe pull engaged in pipe
methods. pulling, bottom
Scenario 2: no impact sounds of
pipeline replacement/ pipe connecting with
installation. seafloor.
Scenario 2: none.
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\1\ The specific years activities that are planned to occur may or may not coincide with the actual year of execution.
\2\ One exploratory well between Anna and Bruce is analyzed to occur in Year 2 and two exploratory wells in the Middle Ground Shoal Unit are analyzed to
occur in Year 4; however, the exploratory wells may be developed in any separate years during the effective period of the LOA.
\3\ Two pipeline scenarios are analyzed to occur: Scenario 1 comprises one project using lay barge methods in Year 2 and one project using pipe pull
methods in Year 4; Scenario 2 comprises two projects using lay barge methods in Year 2 and no additional projects thereafter. A maximum of two
pipeline projects will occur during the effective period of the LOA. Pipeline projects may occur simultaneously in any one year or in separate years
during the effective period of the LOA. However, only lay barge methodology can be utilized in the same year (i.e., Scenario 2).
[[Page 8126]]
Specified Geographical Region
Hilcorp's planned activities will occur in Cook Inlet, Alaska,
which is the specified geographical region. Specifically, activities
would occur in middle Cook Inlet and Trading Bay, Alaska (figure 1)
from a point on the eastern shoreline approximately 12 km (7.5 mi)
south of the East Foreland to a point approximately 16 km (10 mi) south
of Point Possession on the west side, to the northernmost production
platform in middle Cook Inlet (Tyonek, located in the North Cook Inlet
Unit) to a point that is 3.5 km (2.2 mi) north of the village of Tyonek
near the mouth of the Chuitna River. From there the area extends south
to a point along the western shoreline approximately 15 km (9.3 mi)
south of the West Foreland, and across the inlet back to a point on the
eastern shoreline approximately 12 km (7.5 mi) south of the East
Foreland. The geographic area of all activity covers a total of
approximately 1,865 square kilometers (km\2\) (460,850 acres) (within
Cook Inlet in State of Alaska waters). For the purpose of this rule,
middle Cook Inlet refers to waters north of the East and West Forelands
and south of Threemile River in the west and Point Possession in the
east, and Trading Bay refers to waters from approximately Granite Point
in the north to the West Foreland in the south. Upper Cook Inlet refers
to waters north and east of Beluga River in the west and Point
Possession in the east.
BILLING CODE 3510-22-P
[[Page 8127]]
[GRAPHIC] [TIFF OMITTED] TR20FE26.000
BILLING CODE 3510-22-C
[[Page 8128]]
Detailed Description of the Specified Activity
A detailed description of Hilcorp's planned activities are provided
in the proposed rule (90 FR at 34979-34984). Since publication of the
proposed rule, Hilcorp has not made any modifications to their
specified activities; therefore, we refer the reader to the proposed
rule for a detailed description of the specified activities.
Mitigation, monitoring, and reporting measures proposed by Hilcorp and
included in this final rule are also described in detail in the
proposed rule and summarized later in this document (please see
Mitigation and Monitoring and Reporting).
Description of Marine Mammals in the Area of Specified Activities
Twelve species of marine mammals, comprising 15 stocks, may be
taken by harassment incidental to Hilcorp's specified activities. A
complete description of marine mammals status and trends, life history,
habitat use, and threats is included in Hilcorp's application and NMFS'
proposed rule (90 FR at 34984-34994). NMFS is not aware of any new
relevant information since publication of the proposed rule. Please
refer to the proposed rule for detailed descriptions of marine mammals
in the project area.
Table 2--Species With Estimated Take From the Specified Activities
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ESA/ MMPA status; Stock abundance (CV,
Common name Scientific name \1\ Stock strategic (Y/N) Nmin, most recent PBR Annual M/
\2\ abundance survey) \3\ SI \4\
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Order Artiodactyla--Cetacea--Mysticeti (baleen whales)
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Family Eschrichtiidae:
Gray Whale...................... Eschrichtius robustus.. Eastern N Pacific...... -, -, N 26,960 (0.05, 25,849, 801 131
2016).
Family Balaenidae:
Family Balaenopteridae (rorquals):
Fin Whale....................... Balaenoptera physalus.. Northeast Pacific...... E, D, Y 3,168 (0.26, 2,554, UND 0.6
2013) \5\.
Humpback Whale.................. Megaptera novaeangliae. Hawai[revaps]i......... -, -, N 11,278 (0.56, 7,265, 127 27.09
2020).
Mexico-North Pacific... T, D, Y N/A \6\ (N/A, N/A, UND 0.57
2006).
Western North Pacific.. E, D, Y 1,084 (0.088, 1,007, 3.4 5.82
2006).
Minke Whale..................... Balaenoptera Alaska................. -, -, N N/A \7\ (N/A, N/A, N/ UND 0
acutorostrata. A).
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Odontoceti (toothed whales, dolphins, and porpoises)
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Family Delphinidae:
Killer Whale.................... Orcinus orca........... Eastern North Pacific -, -, N 1,920 (N/A, 1,920, 19 1.3
Alaska Resident. 2019).
Eastern North Pacific -, -, N 587 (N/A, 587, 2012).. 5.9 0.8
Gulf of Alaska,
Aleutian Islands and
Bering Sea Transient.
Pacific White-Sided Dolphin..... Lagenorhynchus North Pacific.......... -, -, N 26,880 (N/A, N/A, UND 0
obliquidens. 1990).
Family Monodontidae (white whales):
Beluga Whale.................... Delphinapterus leucas.. Cook Inlet............. E, D, Y 331 (0.076, 311, 2022) 0.62 0
Family Phocoenidae (porpoises):
Dall's Porpoise................. Phocoenoides dalli..... Alaska................. -, -, N UND \8\ (UND, UND, UND 37
2015).
Harbor Porpoise................. Phocoena............... Gulf of Alaska......... -, -, Y 31,046 (0.21, N/A, UND 72
1998).
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Order Carnivora--Pinnipedia
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Family Otariidae (eared seals and
sea lions):
California Sea Lion............. Zalophus californianus. U.S.................... -, -, N 257,606 (N/A, 233,515, 14,011 >321
2014).
Steller Sea Lion................ Eumetopias jubatus..... Western................ E, D, Y 49,837 \9\ (N/A, 299 267
49,837, 2020).
Family Phocidae (earless seals):
Harbor Seal..................... Phoca vitulina......... Cook Inlet/Shelikof -, -, N 28,411 (N/A, 26,907, 807 107
Strait. 2018).
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\1\ Information on the classification of marine mammal species can be found on the web page for The Society for Marine Mammalogy's Committee on Taxonomy
(<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' Stock Assessment Reports, represent annual levels of human-caused mortality plus serious injury from all sources
combined (e.g., commercial fisheries, ship strike). Annual M/SI often cannot be determined precisely and is in some cases presented as a minimum value
or range. A CV associated with estimated mortality due to commercial fisheries is presented in some cases.
\5\ The values presented here are based on the 2020 SAR and are an underestimate for the entire stock because it is based on surveys which covered only
a small portion of the stock's range.
\6\ Abundance estimates are currently considered unknown.
\7\ Reliable population estimates are not available for this stock. Please see Friday et al. (2013) and Zerbini et al. (2006) for additional information
on numbers of minke whales in Alaska.
\8\ The best available abundance estimate is likely an underestimate for the entire stock because it is based upon a survey that covered only a small
portion of the stock's range.
\9\ Nest is best estimate of counts, which have not been corrected for animals at sea during abundance surveys.
[[Page 8129]]
Changes From Proposed to Final Rule
Since publication of the proposed rule, Hilcorp modified the CIBW
density used to estimate take from pipeline replacement/installation
using the lay barge method upon further investigation on where this
activity may occur. They did so as lay barge methodology would be most
appropriate for the deeper waters in middle Cook Inlet, rather than the
shallower waters of Trading Bay. Hilcorp also adjusted the Tyonek
Platform pile driving assumptions (specifically the strike rate) to
mirror those for the exploratory well pile driving activities, which
reduced the number of pile strikes from 24,000 to 2,786 strikes per
day. Upon further investigation of the take estimate calculations, the
``proportion of the day activities would occur'' factor was changed
from a partial day to 1 day (effectively removing it from the equation)
for pile driving and stationary tugs engaged in holding or positioning
a jack-up rig because the amount of work per day is already accounted
for in the Level A harassment isopleth calculations and, for Level B
harassment, there were not data available (e.g., animals/hour) to
develop such refined exposure estimates. A detailed description of all
modifications are provided in the Estimated Take section of this final
rule.
As a result of these changes, distances to Level A harassment
thresholds for winter production impact pile driving at the Tyonek
Platform decreased; calculated exposure estimates increased for certain
activities (specifically, tug operations involving holding or
positioning a jack-up rig and exploratory pile driving); and calculated
exposure estimates associated with Tyonek well development activities
decreased.
NMFS also modified language in the regulatory text (see Sec. Sec.
217.164(g) and 217.165(h)) to clarify that ``[i]n this scenario''
refers to safety and pile refusal/instability concerns and ``any
deviations from the vessel operation requirements'' refers to ``any
instances where mitigation could not be implemented due to safety or
pile instability/refusal concerns,'' respectively.
Comments and Responses
On July 24, 2025, NMFS published a proposed rule in the Federal
Register for a 30-day public comment period. NMFS received 24 comment
submissions in total; 21 from individuals and 3 letters from Defenders
of Wildlife, the Alaska Department of Fish and Game (ADF&G), and a
joint letter from Alaska Wildlife Alliance, Environmental Investigation
Agency, Center for Biological Diversity, and Cook Inletkeeper.
Summaries of all relevant, substantive comments and NMFS' responses to
these comments are provided 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 rule, such as funding
scientific research). 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. All public comments
are available for review on <a href="https://www.regulations.gov">https://www.regulations.gov</a>.
Comment 1: ADF&G supports issuance of the rule, concurring with
NMFS's analyses and determinations in the proposed rule. ADF&G
acknowledged the proposed rule includes numerous mitigation measures to
avoid incidental serious injury or mortality to marine mammals, which
it states helps ensure the conservation of marine mammal stocks.
Lastly, ADF&G states that it does not consider ongoing or proposed oil
and gas activities, with appropriate mitigation measures, to threaten
the conservation or sustainability of marine mammals in Cook Inlet.
Response: NMFS appreciates ADF&G's comments. All mitigation
measures that were discussed by ADF&G and contained within the proposed
rule are included in this final rule.
Comment 2: A commenter recommended NMFS reconsider the Level B
harassment zones considering recent information indicating beluga
behavioral responses to vessels at a significantly greater distance
(citing Martin et al., 2023) than the commenter believes are reflected
in the estimated Level B harassment distances presented in the proposed
rule.
Response: The referenced literature, Martin et al., 2023, documents
the responses of nine satellite-tagged Eastern Beaufort Sea belugas to
encounters with ships in the Beaufort, Chukchi, and Bering Seas from
July through December 2018. The authors indicate that their findings
corroborate previous studies that have shown behavioral responses of
belugas to ships at distances far beyond visual range, implying belugas
react to low-amplitude ship noise near ambient levels. The commenter
recognizes in their letter that the belugas included in this study are
not CIBWs but does not acknowledge that Cook Inlet is naturally a much
louder environment than the seas where the referenced study was
conducted. As described in the proposed rule, Cook Inlet is a
particularly complex acoustic environment with strong currents, large
tides, variable sea floor and generally changing conditions. Background
noise levels in Cook Inlet where CIBWs are present often exceed 120 dB
RMS (e.g., Heenehan, 2009; Blackwell and Greene et al., 2003; URS,
2007; HDR, 2011). Therefore, NMFS does not consider Martin et al., 2023
to be the best available scientific information for CIBW behavioral
response to vessels and has not incorporated it into the Level B
harassment zone calculation.
Comment 3: A commenter recommended that NMFS characterize baseline
conditions for marine mammals in the project area (including a
quantitative or qualitative assessment of the baseline acoustic
environment for marine mammals in Cook Inlet or the project area),
especially CIBWs, so that impacts from the 5 years of proposed
activities can be considered together with existing noise and other
stressors to determine whether the total impact is negligible. The
commenter also recommended identifying spatial and temporal overlap
among stressors and ensuring that impacts are minimized to the greatest
extent possible.
Response: As discussed in the Negligible Impact Analysis and
Determination section of the proposed rule and herein, consistent with
the 1989 preamble for NMFS' implementing regulations (54 FR 40338,
September 29, 1989), the impacts from other past and ongoing
anthropogenic activities are incorporated into the negligible impact
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).
The Description of Marine Mammals in the Area of Specified
Activities section of the proposed rule thoroughly described the
baseline conditions for marine mammals in the project area including
past (e.g., whaling) and ongoing (e.g., noise, subsistence use for
relevant species) stressors for all marine mammal species and stocks,
discussed where these stressors are most prevalent (e.g., ports, where
subsistence hunting occurs, etc.), and described the status of the
species and stocks. The Potential Effects of Specified Activities on
Marine Mammals and Their Habitat section of the proposed rule
described, based on the best available science, the anticipated effects
of the specified activities on marine mammals, including a discussion
about habituation and sensitization of marine
[[Page 8130]]
mammals to their environment and the importance of context when
predicting impacts. The proposed rule also identified Cook Inlet as a
particularly complex acoustic environment with strong currents, large
tides, variable sea floor and generally changing conditions. As
described above, background noise levels in Cook Inlet where CIBWs are
present often exceed 120 dB (e.g., Heenehan, 2009; Blackwell and Greene
et al., 2003; URS 2007; HDR 2011).
Between 1994 and 1998, the CIBW stock declined by approximately 50
percent due largely to unsustainable subsistence harvesting. Since
their listing as endangered under the ESA in October 2008, there have
been 95 confirmed dead stranded Cook Inlet beluga (NMFS, 2002). Live
stranding effects were the leading cause of death (23 percent, n=9)
among belugas necropsied between 1998 and 2013 (n=38), though 29
percent (n=11) had an unknown cause of death (Burek-Huntington et al.,
2015). Burek-Huntington et al. (2015) also noted that disease may have
contributed to the cause of death in some events. Other causes of death
included trauma, malnutrition, and perinatal mortality (fetus or
neonatal calf mortality of unspecified cause). NMFS recognizes that the
CIBW population has not recovered from subsistence harvest and that
noise, among many other stressors such as disease, contaminants, and
natural live strandings, could be a contributing factor to recovery.
However, in the Negligible Impact Analysis and Determination section of
the proposed rule and this final rule, NMFS describes the various
factors considered in our determination that the specified activities,
in combination with Hilcorp's proposed mitigation measures, would not
appreciably contribute to existing noise stressors such that they would
affect the population through effects to recruitment or survival. The
commenter did not provide scientific information that suggests noise
impacts from the specified activities would have more than a negligible
impact on marine mammals.
Comment 4: A commenter asserted that 70 ``days of disturbance''
from pile driving would occur over 5 years, as described in the expert
elicitation (EE) referenced in the proposed rule, and this would be
sufficient to cause potential population-level impact through decreased
foraging success. The commenter recommended that NMFS aggregate the
potential days of disturbance attributable to each proposed activity,
in addition to baseline noise conditions, to support its negligible
impact determination.
Response: NMFS disagrees that exposure to pile driving noise would
cause potential population-level impacts through decreased foraging
success. The best available science supports the analysis that exposure
to pile driving noise would result in temporary behavioral disturbance
that would not have population-level effects. As described in the
proposed rule, extensive monitoring at the Port of Alaska, which is
located north of the project area in Knik Arm and where pile driving
has been ongoing for several years, supports this analysis.
Observations during Port of Alaska pile driving demonstrate that CIBWs
may or may not respond behaviorally and that any observed responses
(e.g., faster swim speeds, tight group formations) are mild and that
CIBWs continue to transverse Knik Arm. Further, the population has not
declined despite extensive pile driving occurring. In fact, from 2016
to 2022, when pile driving at the Port of Alaska has been concentrated,
the CIBW population has slightly increased (Young et al., 2025).
As described in the proposed rule, the EE considered that a ``day
of disturbance,'' in the context of the report, is notably more severe
(e.g., energy reserves of a pregnant CIBW would be reduced to such a
level that she is certain to terminate the pregnancy or abandon the
calf soon after birth) than any Level B harassment expected to result
from these activities, which as described is expected to be comprised
predominantly of temporary modifications in the behavior of individual
CIBWs. As such, NMFS disagrees with the commenter that NMFS should
aggregate days of disturbance as the predicted outcomes of authorizing
take do not rise to the level described in the EE. The proposed rule
summarized relevant literature and monitoring reports related to
potential impacts of pile driving on CIBWs (e.g., POA 2021, 2022) and
concluded that temporary behavioral modifications (e.g., increased
swimming swims, minor avoidance) are the likely outcome of exposure.
Comment 5: A commenter indicated that data in Hilcorp's previous
monitoring reports do not support the following statement in the
proposed rule: ``monitoring data from Hilcorp's activities suggest that
the presence of pile driving or tugs under load do not discourage CIBWs
from transiting throughout Cook Inlet and between critical habitat
areas and that the whales do not abandon critical habitat areas (e.g.,
Horsley and Larson, 2023, 2024).'' The commenter asserted that little
inference regarding the impacts of tugs under load on belugas use of,
or transit to and from, critical habitat areas can be made from this
data and pointed out that example monitoring reports provided consisted
entirely of transporting jack-up rigs as opposed to pile driving.
Response: NMFS acknowledges that the proposed rule inadvertently
omitted citations to the Port of Alaska's monitoring reports, which
thoroughly document responses of CIBWs to pile driving activities, in
the example list. However, in other parts of the proposed rule, NMFS
summarized findings from these reports, including the results of
extensive, multi-year monitoring in Knik Arm, which contains an
important foraging area for CIBWs. These reports clearly demonstrate
that CIBWs may or may not exhibit behavioral response to pile driving;
when behavioral responses were observed, those responses were as
expected (e.g., faster swim speeds, more cohesive group formation,
etc.). CIBWs are also frequently observed around the Port of Alaska and
other smaller ports when vessels are operating. NMFS is unaware of data
suggesting CIBWs do not utilize areas where vessel use or other
activities similar to those used by Hilcorp occur. Nor is NMFS aware of
data indicating that such anthropogenic activity prevents CIBWs from
transiting throughout Cook Inlet and between critical habitat areas, or
that CIBWs have abandoned critical habitat areas due to exposure to
these sources. The commenter did not provide additional scientific
information for NMFS to consider.
Comment 6: A commenter claimed that the negligible impact analysis
in the proposed rule failed to recognize that noise and other stressors
can cause significant disruptions to behaviors, including interrupting,
deferring, and ultimately reducing the use of preferred areas for
critical life functions.
Response: NMFS disagrees that the proposed rule did not thoroughly
describe the potential impacts of noise exposure on marine mammals,
including CIBWs. A full explanation of the potential effects of noise
on marine mammal using the best available science was included in the
Potential Effects of Specified Activities on Marine Mammals and Their
Habitat section of the proposed rule (90 FR at 34994-35005). In the
Negligible Impact Analysis and Determination section of the proposed
rule (90 FR at 35022-35026), NMFS thoroughly described, using the best
available science, why the taking proposed to be authorized incidental
to Hilcorp's specified activities would not affect marine mammal
populations (including CIBWs)
[[Page 8131]]
through effects on annual rates of recruitment or survival. The
proposed rule also explained that while Hilcorp's activities would
occur within critical habitat, they would occur intermittently or, for
pile driving, when CIBWs are not concentrated in the project area.
Science supporting the preliminary determinations in the proposed rule
and determinations in this final rule include extensive monitoring of
activities identical to those proposed by Hilcorp (e.g., tug use by
Hilcorp, pile driving at the Port of Alaska). Overall, NMFS has found,
supported by the best available science, that the taking authorized
from the specified activities will have a negligible impact on marine
mammals, including CIBWs. The commenter did not provide additional
scientific information that supports that the taking authorized would
have more than a negligible impact on marine mammals.
Comment 7: A commenter recommended that NMFS deny issuing the
authorization on the basis that NMFS does not take a precautionary
approach and issuing an LOA risks significant harm to the species and
fails to uphold the objectives of the MMPA and ESA. Specifically,
noting recommendations made outside of this specific rulemaking such as
Recovery Action #62 of the CIBW Recovery Plan, the commenter stated
that a truly precautionary approach would postpone the granting of any
incidental take until (1) there is stronger evidence from more
consistent annual survey effort of sustained population growth over
multiple years, and not potentially unreliable shifts in survey
methodologies; (2) cumulative impacts, including from noise, vessel
traffic, and industrial disturbance, have been robustly assessed and
mitigated, and (3) NMFS and associated partners have fully considered
expert, independent recommendations emphasizing conservation first.
Response: NMFS has made, based on the best available science, the
findings required to promulgate this final rule. The commenter's
recommendations are not based on the applicable statute (see 16 U.S.C.
1371(a)(5)(A)(i) (``[T]he Secretary shall allow . . . the incidental,
but not intentional, taking . . . if the Secretary . . . finds that the
total of such taking . . . will have a negligible impact on such
species or stock and will not have an unmitigable adverse impact of the
availability of such species or stock for taking for subsistence uses .
. . .''). Further, the Biological Opinion associated with this action
concluded that Hilcorp's activities would not jeopardize the continued
existence of ESA-listed species, including CIBWs, or adversely modify
critical habitat.
With respect to Recovery Action 62 (NMFS, 2016), the recommended
action was to review the current system for allocation of takes by
harassment to determine if a comprehensive approach increases managers'
ability to reduce cumulative effects. This recovery action applies to
both incidental and intentional (i.e., research) takes. Castellotte et
al. (2018) also recommended a new approach to authorizing CIBW takes;
however, this approach is inconsistent with Section 101(a)(5)(A) of the
MMPA (16 U.S.C. 1371(a)(5)(A)). Here, we appropriately made the
findings required under the MMPA and have promulgated the requested
regulations and issued the LOA. As described in the response to comment
10, NMFS incorporates past and ongoing actions into the baseline status
of marine mammal species and stocks when considering if the authorized
take would have a negligible impact on the affected species and stocks
or have unmitigable adverse impacts on the availability of species for
subsistence use.
Comment 8: A commenter asserted that NMFS's reliance on arbitrary
numerical thresholds to justify ``small take'' or ``negligible impact''
fails to account for the precarious conservation status of CIBWs. The
commenter stated that the ``logic that any disturbance under a certain
percentage is acceptable does not hold when the baseline is an
endangered population on the brink of extinction.''
Response: NMFS disagrees, and the commenter did not provide
additional information for NMFS to consider to support this claim.
Legislative history shows that Congress recognized ``the imprecision of
the term `small numbers,' but was unable to offer a more precise
formulation because the concept is not capable of being expressed in
absolute numerical limits.'' H.R. Rep. No. 97-228, at 19 (1981), as
reprinted in 1981 U.S.C.C.A.N. 1458, 1469. In 2021, NMFS adopted a
``proportional approach,'' whereby it ``compares the number of
individuals taken to the most appropriate estimation of abundance of
the relevant species'' to determine whether the authorized take is
limited to ``small numbers'' of that species (see, e.g., ``Taking
Marine Mammals Incidental to Geophysical Surveys Related to Oil and Gas
Activities in the Gulf of Mexico,'' (86 FR 5322, Jan. 19, 2021)); see
also 90 FR 31756 (Jul. 15, 2025) (applied to incidental take during
construction activities); 86 FR 27991 (May 25, 2021) (scientific
research activities), and 85 FR 40250 (Jul. 6, 2020) (renewable energy
activities).
Federal courts have upheld this proportional approach, which is
used by both NMFS and U.S. Fish and Wildlife Service for all incidental
take authorizations issued under the MMPA (see, e.g., Center for
Biological Diversity v. Salazar, 694 F.3d 893, 906-907 (9th Cir.
2012)). NMFS has defended the approach successfully in court where the
issue has been raised in litigation for various authorizations (see
Melone v. Coit, 100 F.4th 21, 30-32 (1st Cir. 2024) (upholding NMFS
application of the proportional approach); Save Long Beach Island v.
U.S. Dep't of Commerce, 2025 WL 1829543, at *26 (upholding NMFS
application of the proportional approach); see also Native Village of
Chickaloon v. NMFS, 947 F. Supp. 2d 1031, 1052-1053 (D. Ak) (upholding
NMFS finding that the non-lethal take of 30 beluga whales during
seismic surveys in Cook Inlet, Alaska, which amounted to 10 percent of
the total whale population, constitutes a small number)). As described
in the proposed rule and this final rule, NMFS has made the required
small numbers determination consistent with this approach. The number
of takes authorized is a component of a negligible impact analysis (see
Nat. Res. Def. Council, Inc. v. Evans, 279 F. Supp. 2d 1129, 1153 (N.D.
Cal. 2003), and we refer to Negligible Impact Analysis and
Determination sections of the proposed rule and herein for the complete
analysis.
Comment 9: A commenter took issue with NMFS' use of standard
rounding, (i.e., rounding down when an estimated value is less than
0.5). The commenter claimed that the number of takes proposed to be
authorized is an underestimate because, when adding all the fractional
parts of the estimated harassment events identified in table 18 of the
proposed rule over the 5-year period, it totals 97.959 exposures (0.104
Level A and 97.855 Level B) and the proposed rule only proposed to
authorize 94 Level B harassment takes. The commenter also stated that
NMFS assumes that anthropogenic noise in the Level B harassment zone
will deter whales from entering the Level A harassment zone, thus
reducing the likely number of takes by Level A harassment, and states
that this assumption is ``under-protective of the whales.''
Response: NMFS disagrees that takes were rounded down. Where total
exposures for each activity exceeded a whole integer (e.g., 5.2
exposures), exposures were rounded up. That is, exposure estimates were
rounded up for
[[Page 8132]]
each activity before summing (e.g., if the exposure estimate for pile
driving at Tyonek platform was 27.3, the agency rounded up to 28 before
adding across all activities). As identified in the Estimated Take
section of this final rule (table 4), the total number of beluga whale
takes were adjusted from 94 across 5 years in the proposed rule to 147
in this final rule. The sum of exposure estimates across all activities
for scenario 1 equals 143.6. However, after rounding for each activity
before summing exposure estimates, the total equals the 147 takes
requested and which NMFS has authorized. NMFS further notes the sum of
exposure estimates across all activities for scenario 2 equals 134.1;
therefore, the authorized number of takes is conservative.
Level A harassment exposures of CIBWs were calculated (0.013
animals/per maximum); however, Hilcorp did not request, and NMFS has
not authorized, take by Level A harassment for this species. As
described in the Estimated Take section below, the Level A harassment
exposure estimates consider a distance to the Level A harassment
threshold that represents the distance at which an animal would have to
remain for the duration of activity occurring within 24 hours and do
not consider mitigation measures (e.g., seasonal pile driving
restrictions at the Tyonek Platform, clearance and shutdown) which
further reduces the likelihood of a CIBW accruing enough noise energy
to meet the onset of AUD INJ threshold. For these reasons, Hilcorp did
not request and NMFS agrees that that authorizing take of CIBWs by
Level A harassment is unlikely and is not authorized.
Comment 10: A commenter asserted that NMFS failed to adequately
consider cumulative effects to CIBW.
Response: MMPA section 101(a)(5)(A) and (D) requires NMFS to
authorize the requested incidental take of small numbers of marine
mammals of a species or stock by U.S. citizens if it finds the total
take ``while engaging in that [specified] activity'' within a specified
geographical 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)(A)). Negligible impact is defined 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 effect on annual rates of recruitment or
survival'' (50 CFR 216.103). Consistent with the preamble of NMFS'
implementing regulations (54 FR 40338, September 29, 1989), the impacts
from other past and ongoing anthropogenic activities are factored into
the baseline, which is considered in the negligible impact analysis.
Federal courts have repeatedly upheld NMFS's approach. See Melone v.
Coit, 100 F.4th 21, 33 (1st. Cir. 2024) (upholding NMFS' approach);
Save Long Beach Island v. U.S. Dep't of Commerce, 794 F.Supp.3d 273,
325-327 (D.N.J. 2025) (same).
Potential Effects of Specified Activities on Marine Mammals and Their
Habitat
The effects of underwater noise from Hilcorp's oil and gas
exploration, development, production, and decommissioning activities
have the potential to result in harassment of marine mammals in Cook
Inlet, Alaska. We refer the reader to the proposed rule (90 FR 34974 at
34994-35005) for a full discussion of the effects of anthropogenic
noise on marine mammals in general and the potential effects of the
specified activities on marine mammals and their habitat. There is no
newly available relevant information that would change our analyses or
the results thereof.
Estimated Take of Marine Mammals
Harassment is the only type of take expected to result from these
activities. Except with respect to certain activities not pertinent
here, section 3(18) of the MMPA defines ``harassment'' as any act of
pursuit, torment, or annoyance, which (i) has the potential to injure a
marine mammal or marine mammal stock in the wild (Level A harassment)
or (ii) has the potential to disturb a marine mammal or marine mammal
stock in the wild by causing disruption of behavioral patterns,
including, but not limited to, migration, breathing, nursing, breeding,
feeding, or sheltering (Level B harassment).
Authorized takes would primarily be by Level B harassment, as use
of the acoustic sources (i.e., pile driving and tugging activities,
including those planned for anchor handling, pipe-pulling, and jack-up
rig moves) have the potential to result in disruption of behavioral
patterns for individual marine mammals. We note here that given the
slow, predictable, and generally straight path (or stationary nature)
of tugs towing, holding, and positioning the jack-up rig or engaged in
anchor handling or pipe pulling activities, the likelihood of
disrupting marine mammal behavioral patterns from tug use that would
qualify as harassment under the MMPA is considered relatively low.
However, at the request of the applicant, we have quantified the
potential exposures from this activity to our generalized harassment
thresholds, assumed that these exposures would equate to take, and
analyzed the impacts of the assumed takes.
The likelihood of Auditory Injury (AUD INJ) is also considered
relatively low for all species given that to experience Level A
harassment, an animal would have to remain at the calculated distance
from an activity for its total duration in a given day, which Hilcorp
assumes would be up to 8 hours for pile driving or 2 or more hours for
anchor handling associated with lay barge pipeline installation or
replacement. Required clearance and shutdown zones also encompass
conservative Level A harassment distances. Regardless, with the
exception of CIBWs, Hilcorp requested, and NMFS has authorized, Level A
harassment of 9 species of marine mammals wherein this scenario occurs
(e.g., pile driving at the exploratory wells) and the calculated
exposure estimates are greater than zero despite the very low risk of
AUD INJ occurring (see table 4). For all species, the exposure estimate
calculations do not reflect consideration of mitigation measures (e.g.,
clearance and shutdown), which further reduce the likelihood of an
animal incurring AUD INJ, or potential avoidance behavior in response
to noise exposure (e.g., Southall et al., 2021). For CIBWs, the maximum
annual exposure estimate is greater than zero (0.013). However, Hilcorp
proposed, and NMFS is requiring, enhanced, species-specific mitigation
measures (i.e., seasonal restrictions to winter pile driving at the
Tyonek Platform, which reduces the likelihood animals would persist in
the area of pile driving as this activity would occur outside key
foraging time periods, as well as delaying the commencement of anchor
handling if a CIBW is observed at any distance). For all these reasons,
Hilcorp did not request, and NMFS has not authorized, Level A
harassment of CIBWs. The required mitigation and monitoring measures
are expected to minimize the potential for take and, if take were to
occur, the severity of the taking to the extent practicable. As
described previously, no serious injury or mortality is anticipated or
authorized for any species, and Level A harassment of CIBW is not
anticipated due to inherently low probability of AUD INJ occurring and
enhanced, species-specific mitigation.
NMFS refers the reader to the Estimated Take of Marine Mammals
[[Page 8133]]
section of the proposed rule (see 90 FR at 35005-35017). Except for the
numerical changes described herein, this analysis remains valid and is
not repeated here. Since publication of the proposed rule, Hilcorp made
adjustments to assumptions used in the modeling and the exposure
estimate methodology to prevent redundant accounting of the duration
component of project activities and to provide greater clarity
regarding the details of pile driving operations. Specifically, Hilcorp
made the following modifications, and NMFS agrees these are appropriate
to carry forward in this analysis:
<bullet> For lay barge pipeline replacement and installation
activities, beluga whale density estimates specific to middle Cook
Inlet were utilized in the exposure estimate equations to reflect the
potential for these operations to occur at any platform within the
region (note pipe pull operation exposure estimates continued to be
calculated using the Trading Bay density values, as these activities
are most likely to be conducted from the western shoreline of Cook
Inlet). As such, the density was changed from the Goetz modeled density
in Trading Bay of 0.01505, which represents densities in shallow waters
(see 90 FR at 35013), to the MML middle Cook Inlet density of 0.00658,
which represents densities in deeper waters where lay barge pipeline
replacement and installation activities would occur. NMFS notes that
both densities were identified in table 17 of the proposed rule. All
other densities remain the same as in the proposed rule.
<bullet> Impact pile driving strike rate at the Tyonek Platform was
made identical to that estimated for exploratory well pile driving (65
strikes per foot), which decreased the number of strikes estimated to
install a pile from 24,000 strikes per pile (see 90 FR at 35006) to
19,500 strikes per pile (which is a factor in the Level A harassment
distance calculation). Hilcorp maintains that 7 days are needed to
install each pile; therefore, approximately 2,786 strikes per day
(19,500 strikes/7 days) would occur at the Tyonek Platform. NMFS notes
that the Level A harassment distances in Hilcorp's application and the
proposed rule assumed all 24,000 strikes occurred on one day;
therefore, the distance to the Level A harassment thresholds were
overestimated. Making these adjustments reduced calculated distances to
Level A harassment isopleths (table 3).
<bullet> For pile driving and stationary tugs engaged in holding or
positioning a jack-up rig, the ``proportion of the day activities would
occur'' factor was changed from a partial day (see 90 FR at 35013) to 1
day (effectively removing it from the equation) because the amount of
work per day is already accounted for in the Level A harassment
isopleth calculations and, for Level B harassment, there were not data
available (e.g., animals/hour) to develop such refined exposure
estimates.
As a result of these modifications, distances to Level A harassment
thresholds for winter production impact pile driving at the Tyonek
Platform decreased; calculated exposure estimates increased for certain
activities (specifically, tug operations involving holding or
positioning a jack-up rig and exploratory pile driving); and calculated
exposure estimates associated with Tyonek well development activities
decreased. Specifically, the updated exposure estimates resulted in an
annual increase to estimated Level B harassment for several species:
humpback whales (+2), beluga whales (+7), harbor porpoises (+1), harbor
seals (+302), and Steller sea lions (+8). Conversely, estimated Level A
harassment decreased for harbor porpoises (from 4 to 1) and harbor
seals (from 43 to 15). Table 4 presents a side-by-side comparison of
the annual take estimates in the proposed rule versus those estimated
and allowed for in this final rule and authorized in the LOA. Table 5
compares the aggregated take authorization requests over the 5-year
period. Analysis pertaining to pipeline replacement and/or installation
activities remained unchanged, as these did not warrant methodological
refinement.
Table 3 contains updated distances to thresholds and corresponding
areas for pile driving activities. Table 4 provides updated annual
exposure estimates across all activities and maximum amount of annual
take to be authorized in an LOA, if issued. Table 5 includes updated
maximum amount of take authorized in the LOA, across all 5 years.
Table 3--Comparison of Calculated Distances and Areas to the Estimated Level A and Level B Harassment Thresholds for Pile Driving Activities Between
Proposed And Final Rule
--------------------------------------------------------------------------------------------------------------------------------------------------------
Level A harassment (SEL) distance (m)/area (km\2\) Level B harassment
Activity -------------------------------------------------------------------------------- distance (m)/area
LF HF VHF PW OW (km\2\)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Proposed Rule
--------------------------------------------------------------------------------
Winter production impact pile driving (Tyonek 3,295.85/34.13 420.51/0.56 5,100.30/81.72 2,927.89/26.93 1,091.31/3.74 1,000.00/3.14
Platform)........................................
-----------------------------------------------------------------------------------------------------
Final Rule \1\
--------------------------------------------------------------------------------
784.24/1.93 100.06/0.03 1,213.61/4.63 696.69/1.52 259.70/0.21
--------------------------------------------------------------------------------------------------------------------------------------------------------
Exploratory impact pile driving \2\............... 1,041.78/3.41 132.92/0.06 1,612.16/8.17 925.48/2.69 344.98/0.37 1,000.00/3.14
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ Hilcorp originally assumed that, for impact driving at the Tyonek Platform, each pile would require 24,500 strikes to install. While they
acknowledged that a pile could take 7 days to install, their Level A harassment distance calculations assumed all 24,500 strikes would occur in a
single day. Hilcorp subsequently determined that the strike rate for exploratory impact pile driving was a better approximation and has carried over
those assumptions to pile driving at the Tyonek Platform (65 strikes per foot by 300 ft (91 m) divided by a total of 7 days to complete each pile, for
a total of 2,786 strikes per day). These calculation changes decrease and more accurately reflect the potential distances to Level A harassment
thresholds for all hearing groups.
\2\ There is no change between proposed and final rule for exploratory well impact pile driving calculations.
BILLING CODE 3510-22-P
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BILLING CODE 3510-22-C
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Table 5--Comparison of Calculated Maximum Exposure Estimates and Take, by Level A and Level B Harassment,
Authorized Over 5 Years
----------------------------------------------------------------------------------------------------------------
Total 5-year level A take Total 5-year level B take
Species Stock ---------------------------------------------------------------
Proposed Final Proposed Final
----------------------------------------------------------------------------------------------------------------
Humpback whale................ Mexico N Pacific 5 5 30 33
W. N. Pacific...
Hawaii..........
Minke whale................... Alaska.......... 5 5 15 15
Gray whale.................... Eastern Pacific. 5 5 25 25
Fin whale \1\................. Northeastern 5 5 15 15
Pacific.
Killer whale \1\.............. Alaska Resident. 5 5 50 50
Alaska
Transient..
Beluga whale.................. Cook Inlet...... 0 0 94 147
Dall's porpoise \1\........... Alaska.......... 5 5 50 50
Harbor porpoise............... Gulf of Alaska.. 10 5 44 65
Pacific white-sided dolphin North Pacific... 0 0 15 15
\2\.
Harbor seal................... Cook Inlet/ 184 44 2,884 4,516
Shelikof.
Stellar sea lion.............. Western......... 5 5 74 114
California sea lion \2\....... U.S............. 0 0 10 10
----------------------------------------------------------------------------------------------------------------
\1\ Signifies species for which group behaviors influenced the amount of Level B harassment to be authorized.
\2\ Signifies species for which Level B harassment was based on the number of individuals sighting during past
project as monitoring exposures were not modeled due to lack of density data.
Mitigation
If the required findings are made, the MMPA requires NMFS to
prescribe regulations setting forth the permissible methods of taking
pursuant to the activity and other means of effecting the least
practicable adverse 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 (referred to as mitigation).
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
effect 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 analysis considers the nature of the
potential adverse impact being mitigated (likelihood, scope, range),
the likelihood that the measure will be effective if implemented
(probability of accomplishing the mitigating result if implemented as
planned), the likelihood of effective implementation (probability
implemented as planned), and
(2) The practicability of the measures for applicant
implementation, which may consider such things as cost and impact on
operations.
For a full discussion of NMFS' implementation of the least
practicable adverse impact standard, see 89 FR at 31517-31518.
The mitigation requirements in this final rule were proposed by
Hilcorp in its adequate and complete application or are the result of
subsequent coordination between NMFS and Hilcorp. Hilcorp 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 refers the reader to the Proposed Mitigation section of the
proposed rule (see 90 FR at 35017-35021). These measures remain valid
and are not repeated here. In summary, the mitigation measures in this
final rule include seasonal pile driving restrictions at the Tyonek
Platform, use of clearance and shutdown zones (table 6), use of
favorable tides to reduce vessel noise, and implementation of vessel
strike avoidance measures. Hilcorp is required to utilize NMFS-approved
PSOs during all activities that have the potential to result in take of
marine mammals.
Table 6--Clearance and Shutdown Zones by Activity
----------------------------------------------------------------------------------------------------------------
Clearance zone
Activity Species or hearing group (m) Shutdown zone (m)
----------------------------------------------------------------------------------------------------------------
Production and Exploratory Drilling
----------------------------------------------------------------------------------------------------------------
Tugs Towing, Holding, or Positioning a Jack- CIBWs........................ Any distance N/A
Up Rig \1\.
Non-CIBWs.................... 1,500 N/A
----------------------------------------------------------------------------------------------------------------
Production Well Development at the Tyonek Platform
----------------------------------------------------------------------------------------------------------------
Winter Pile Driving........................ All Marine Mammal Species.... 500 500
----------------------------------------------------------------------------------------------------------------
[[Page 8137]]
Exploratory Drilling: MGS Unit and Between Anna and Bruce
----------------------------------------------------------------------------------------------------------------
Exploratory Pile Driving................... VHF Cetaceans................ 1,650 1,650
LF Cetaceans, HF Cetaceans, 1,200 1,200
Phocids, Otariids.
----------------------------------------------------------------------------------------------------------------
Pipeline Replacement or Installation
----------------------------------------------------------------------------------------------------------------
Anchor Handling \1\........................ CIBWs........................ Any distance N/A
Non-CIBWs.................... 1,500 N/A
Pipe Pulling \1\........................... CIBWs........................ Any distance N/A
Non-CIBWs.................... 1,500 N/A
----------------------------------------------------------------------------------------------------------------
\1\ This activity cannot shut down once started and therefore has no associated shutdown zone.
Based on our evaluation of the measures proposed by Hilcorp and
included in the regulations, NMFS has determined that the required
mitigation 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 take authorization for an activity, section
101(a)(5)(A) 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 to both compliance and ensuring that the most value is
obtained from the required monitoring.
Monitoring and reporting requirements prescribed by NMFS should
contribute to improved understanding of one or more of the following:
<bullet> Occurrence of marine mammal species or stocks in the area
in which take is anticipated (e.g., presence, abundance, distribution,
density);
<bullet> Nature, scope, or context of likely marine mammal exposure
to potential stressors/impacts (individual or cumulative, acute or
chronic) through better understanding of (1) action or environment
(e.g., source characterization, propagation, ambient noise), (2)
affected species (e.g., life history, dive patterns), (3) co-occurrence
of marine mammal species with the activity, or (4) biological or
behavioral context of exposure (e.g., age, calving or feeding areas);
<bullet> Individual marine mammal responses (behavioral or
physiological) to acoustic stressors (acute, chronic, or cumulative),
other stressors, or cumulative impacts from multiple stressors;
<bullet> How anticipated responses to stressors impact either (1)
long-term fitness and survival of individual marine mammals or (2)
populations, species, or stocks;
<bullet> Effects on marine mammal habitat (e.g., marine mammal prey
species, acoustic habitat, or other important physical components of
marine mammal habitat); and
<bullet> Mitigation and monitoring effectiveness.
The monitoring and reporting requirements included in this final
rule were proposed by Hilcorp in its adequate and complete application
or are the result of subsequent coordination between NMFS and Hilcorp.
Hilcorp has agreed to the requirements in the regulations, which
include the measures described in the Proposed Monitoring and Reporting
section of the proposed rule (see 90 FR at 35021-35022). These measures
remain valid and are not repeated here. In summary, Hilcorp will
utilize PSOs at least 30 minutes prior to, during, and 30 minutes after
all activities that may result in take of marine mammals using
appropriate equipment. The minimum number of PSOs, watch position, and
locations are provided in table 7. Hilcorp will also provide
situational and regularly scheduled reports.
Table 7--PSO Stations and Locations per Activity
----------------------------------------------------------------------------------------------------------------
On-watch count and
Activity Number of PSOs position PSO location(s)
----------------------------------------------------------------------------------------------------------------
Tugs Towing, Holding, or Positioning a 4 2 on watch (1 port, 1 Jack-Up Rig.
Jack-Up Rig. starboard).
Tugs Towing, Holding, or Positioning a 6-8 2 on watch (1 port, 1 Jack-Up Rig.
Jack-Up Rig at Tyonek Platform. starboard). Tyonek Platform.
1 on watch................
Winter Season Pile Driving for 4-6 2 on watch (1 port, 1 Tyonek Platform.
Production Well Development. starboard).
Pile Driving for Exploratory Drilling... 4 2 on watch (1 port, 1 Drilling Rig.
starboard).
Anchor Handling......................... 2-3 1 on watch................ Anchor Handling Vessel.
Pipe Pulling............................ 4-6 1 on watch \1\............ Pipe Pulling Vessel.
2 on watch (1 port, 1 Nearest Platform.
starboard).
----------------------------------------------------------------------------------------------------------------
\1\ The placement of additional PSOs on the pipe pull vessel and platform were evaluated by Hilcorp and
determined to be impractical due to the necessity of another vessel to accommodate the extra PSOs.
[[Page 8138]]
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), effects on
habitat, and the likely effectiveness of the mitigation. We also assess
the number, intensity, and context of estimated takes by evaluating
this information relative to population status. Consistent with the
1989 preamble for NMFS' implementing regulations (54 FR 40338,
September 29, 1989), the impacts from other past and ongoing
anthropogenic activities are incorporated into this analysis via their
impacts on the baseline (e.g., as reflected in the regulatory status of
the species, population size and growth rate where known, ongoing
sources of human-caused mortality, or ambient noise levels).
As described in the proposed rule, there are several key factors to
assess whether potential impacts associated with a specified activity
should be considered negligible. These include, but are not limited to,
the type and magnitude of taking, the amount and importance of the
available habitat for the species or stock that is affected, the
duration of the anticipated effect on the individuals, and the status
of the species or stock.
As described in the Changes from Proposed to Final Rule section and
Estimated Take section of this final rule, Hilcorp identified and NMFS
incorporated minor adjustments to the estimated take assumptions and
methodology for select activities that resulted in a small decrease of
Level A harassment for harbor porpoise and harbor seals and an overall
small increase in the number of Level B harassment takes for humpback
whales, beluga whales, harbor porpoise, harbor seals, and Steller sea
lions. However, these limited changes do not affect the analyses in the
Negligible Impact Analysis and Determination section of the proposed
rule.
NMFS refers the reader to the general discussion in the Negligible
Impact Analysis and Determination section of the proposed rule (see 90
FR at 35022-35025). This analysis remains valid and is not repeated
here. In summary, the following factors support our determinations that
the impacts resulting from Hilcorp's activities are not expected to
affect any individual marine mammal's fitness for survival or
reproduction and thus are not expected to adversely affect the species
or stocks through effects on annual rates of recruitment or survival:
<bullet> No takes by mortality or serious injury are anticipated or
authorized;
<bullet> Level A harassment is expected to be of a low degree and
would not impact the fitness of any animals;
<bullet> The intensity of anticipated takes by Level B harassment
is low for all stocks consisting of, at worst, temporary modifications
in behavior and would not be of a duration or intensity expected to
result in impacts on reproduction or survival;
<bullet> Exposure and resulting impacts would likely be brief given
the short duration of the specified activity and the transiting
behavior of marine mammals in the action area;
<bullet> Marine mammal densities are low where and when Hilcorp
would conduct activities; therefore, there would not be substantial
numbers of marine mammals exposed to the noise from the project
compared to the affected population sizes;
<bullet> Take would not occur in places and/or times where take is
more likely to result in impacts on reproduction or survival, such as
within ESA-designated or proposed critical habitat or Biologically
Important Areas (other than for CIBWs as described below), or other
habitats critical to recruitment or survival (e.g., rookery);
<bullet> The area ensonified by Hilcorp's activities represents a
very small portion of the available foraging area for all potentially
impacted marine mammal species;
<bullet> Take would occur only within middle Cook Inlet and Trading
Bay--a limited, confined area of any given stock's home range;
<bullet> Monitoring reports from previous projects with pile
driving or tugging activities in Cook Inlet have documented little to
no observable effect on individuals of the same species impacted by the
specified activities; and
<bullet> The mitigation requirements are expected to be effective
in reducing the effects of the specified activity by minimizing the
numbers of marine mammals exposed to sound and the intensity of the
exposures.
Cook Inlet Beluga Whales. For CIBWs, in the proposed rule we
identified additional factors in addition to the factors discussed
above for all species in the context of potential impacts to this
endangered stock based on our evaluation of the take proposed for
authorization. As described in the Changes from Proposed to Final Rule
section and Estimated Take section, the number of Level B harassment
conservatively expected to occur incidental to the specified activities
increased from a maximum of 27 takes annually to 34 (a minor increase
of 7 takes in a given year); across the 5-year effective period of the
rule, the total number of Level B harassment takes to be authorized
increased from 94 to 147, or 10.2 percent of the population assuming
each take is of a different individual. We anticipate that disturbance
to CIBWs would manifest in the same manner as other marine mammals
described in the Negligible Impact Analysis and Determination section
of the proposed rule (see 90 FR at 35025-35026) (e.g., increased
swimming speeds, changes in the direction of travel and dive behaviors,
increased respiration rates, decreased foraging (if such activity were
occurring), or alterations to communication signals) and we refer the
reader to that section. NMFS recognizes that the CIBW population has
fluctuated over the past 10 years and additional data are needed to
address uncertainty regarding the current population trend. However,
data over the past 6 years have shown a potential increase despite
anthropogenic activities occurring in their critical habitat, including
upper Cook Inlet where foraging is most concentrated (NMFS, 2024). In
addition, large numbers of CIBWs have continued to use and pass through
the project area, likely traveling to critical foraging grounds found
in upper Cook Inlet, while noise-producing anthropogenic activities,
including vessel use, have taken place during the past two decades
(e.g., Shelden et al., 2013, 2015b, 2017, 2022; Shelden and Wade, 2019;
Goetz et al., 2023). Overall, the best available science supports the
conclusion that CIBWs may experience some temporary Level B
(behavioral) harassment from exposure to Hilcorp's specified
activities; however, impacts to the population through effects to
annual
[[Page 8139]]
rates of recruitment or survival are not anticipated.
In summary, the following factors support our determination that
the impacts resulting from Hilcorp's planned activities are not
expected to adversely affect the CIBWs through effects on annual rates
of recruitment or survival:
<bullet> The area of exposure would be limited to habitat primarily
used for transiting and not areas known to be of particular importance
for feeding or reproduction;
<bullet> The activities are not expected to result in CIBWs
abandoning critical habitat nor are they expected to restrict passage
of CIBWs within or between critical habitat areas; and
<bullet> Any disturbance to CIBWs is expected to be limited to
temporary modifications in behavior and would not be of a duration or
intensity expected to result in impacts on reproduction or survival.
Based on the analysis contained herein of the likely effects of the
specified activity on marine mammals and their habitat, and taking into
consideration the implementation of the required monitoring and
mitigation measures, NMFS finds that the total marine mammal take from
the planned specified activity would 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)(A) and (D) of the MMPA for
specified activities other than military readiness activities. The MMPA
does not define small numbers and so, in practice, where estimated
numbers are available, NMFS compares the maximum number of individuals
taken in any year 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 maximum annual 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 (see 86 FR 5322, January 19, 2021).
Additionally, other qualitative factors may be considered in the
analysis, such as the temporal or spatial scale of the activities.
The maximum annual number of takes allowed under the final rule is
less than one-third of the best available population abundance
estimates--a specifically, less than 4 percent for all stocks, except
for CIBWs whose maximum annual number of takes allowed is 10.2 percent
of the stock assuming all takes are of a different individual (table
4). NMFS notes this is a minor increase from the proposed rule wherein
the maximum number of annual CIBW takes was 9.68 percent. The numbers
of animals authorized to be taken are small relative to the relevant
species or stock abundances even if each estimated take occurred to a
new individual.
NMFS refers the reader to the discussion in the Small Numbers
section of proposed rule regarding population abundance for the Mexico-
North Pacific stock of humpback whale, Alaska stock of minke whale,
Northeastern Pacific stock of fin whales, and Alaska stock of Dall's
porpoise (see 90 FR at 35026-35027). This information remains valid and
is not repeated here. Based on our analysis of the specified activities
(including the mitigation and monitoring measures) and the anticipated
take of marine mammals, NMFS finds that small numbers of marine mammals
would be taken relative to the population size of the affected species
or stocks.
Unmitigable Adverse Impact Analysis and Determination
In order to issue an ITA, NMFS must find that the specified
activity will not have an ``unmitigable adverse impact'' on the
subsistence uses of the affected marine mammal species or stocks by
Alaskan Natives. NMFS has defined ``unmitigable adverse impact'' in 50
CFR 216.103 as an impact resulting from the specified activity: (1)
that is likely to reduce the availability of the species to a level
insufficient for a harvest to meet subsistence needs by (i) causing the
marine mammals to abandon or avoid hunting areas, (ii) directly
displacing subsistence users, or (iii) placing physical barriers
between the marine mammals and the subsistence hunters; and (2) that
cannot be sufficiently mitigated by other measures to increase the
availability of marine mammals to allow subsistence needs to be met.
NMFS refers the reader to the discussion in the Unmitigable Adverse
Impact Analysis and Determination section of the proposed rule (see 90
FR at 35027). This analysis remains valid and is not repeated here. In
summary, any harassment to marine mammals would primarily be limited to
minor behavioral changes (e.g., increased swim speeds, changes in dive
behaviors and communication signals, temporary avoidance near the tugs)
and is anticipated to be short-term, mild, and not result in any
abandonment or behaviors that would make the animals unavailable to
Alaska Natives for subsistence uses. Hilcorp has developed a
Stakeholder Engagement Plan that includes subsistence communities to
minimize adverse effects on the availability of subsistence marine
mammals for subsistence purposes from the activities.
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 Hilcorp's activities.
Adaptive Management
The regulations governing the take of marine mammals incidental to
Hilcorp's proposed oil and gas activities would contain an adaptive
management component.
The reporting requirements associated with this rule are designed
to provide NMFS with monitoring data from the previous year to allow
consideration of whether any changes are appropriate. The use of
adaptive management allows NMFS to consider new information from
different sources to determine (with input from Hilcorp regarding
practicability) on an annual basis if mitigation or monitoring measures
should be modified (including additions or deletions). Mitigation or
monitoring measures could be modified if new data suggests that such
modifications would have a reasonable likelihood of more effectively
achieving the goals of the mitigation and monitoring and if the
measures are practicable.
The following are some of the possible sources of applicable data
to be considered through the adaptive management process: (1) results
from monitoring reports, as required by MMPA authorizations; (2)
results from general marine mammal and sound research; and (3) any
information which reveals that marine mammals may have been taken in a
manner, extent, or number not authorized by these regulations or
subsequent LOAs.
Endangered Species Act
Section 7(a)(2) of the ESA of 1973 (16 U.S.C. 1531 et seq.)
requires that each Federal agency insure that any action it authorizes,
funds, or carries out is not likely to jeopardize the continued
existence of any endangered or threatened species or result in the
destruction or adverse modification of designated critical habitat. To
ensure ESA compliance for the issuance of ITAs, NMFS consults
internally whenever we propose to authorize take
[[Page 8140]]
for endangered or threatened species, in this case with the NMFS Alaska
Regional Office (AKRO).
NMFS proposed to authorize take of humpback whale (Mexico Distinct
Population Segment (DPS) and Western North Pacific DPS), fin whale
(Northeastern Pacific stock), beluga whale (Cook Inlet DPS), and
Steller sea lion (Western DPS), which are listed under the ESA. NMFS
Office of Protected Resources requested initiation of section 7
consultation with NMFS AKRO for its proposed action (i.e.,
authorization to take marine mammals incidental to Hilcorp's specified
activities). NMFS issued a Biological Opinion on December 19, 2025,
concluding that the promulgation of the rule and issuance of LOA
thereunder is not likely to jeopardize the continued existence of
threatened and endangered species under NMFS' jurisdiction and is not
likely to result in the destruction or adverse modification of
designated or proposed critical habitat.
National Environmental Policy Act
To comply with the National Environmental Policy Act of 1969 (NEPA;
42 U.S.C. 4321 et seq.) and NOAA Administrative Order (NAO) 216-6A,
NMFS must review our proposed action (i.e., promulgation of regulations
and subsequent issuance of an LOA thereunder) with respect to potential
impacts on the human environment. Accordingly, NMFS has prepared an
Environmental Assessment (EA) to evaluate the environmental impacts
associated with the proposed issuance of the regulations and LOA. NMFS'
draft EA was made available during the proposed rule public comment
period. No comments on the EA were received. NMFS has issued a final EA
and Finding of No Significant Impact (FONSI) available at <a href="https://www.fisheries.noaa.gov/action/incidental-take-authorization-hilcorp-alaska-llcs-oil-and-gas-activities-cook-inlet-alaska">https://www.fisheries.noaa.gov/action/incidental-take-authorization-hilcorp-alaska-llcs-oil-and-gas-activities-cook-inlet-alaska</a>.
Promulgation
As a result of these determinations, NMFS is promulgating these
regulations that (1) allow for the take of 12 marine mammal species,
comprising 15 stocks, by Level B harassment, and take by Level A
harassment of 9 of those 12 species, comprising 12 stocks, incidental
to activities conducted by Hilcorp in support of oil and gas
exploration, development, production, and decommissioning over a 5-year
period (no serious injury or mortality is anticipated or authorized)
and (2) prescribe mitigation, monitoring and reporting measures.
Waiver of Delay in Effective Date
The Assistant Administrator for Fisheries has determined that there
is a sufficient basis under the Administrative Procedure Act (APA) to
waive the 30-day delay in the effective date of the regulations
contained in the final rule. Section 553 of the APA provides that the
required publication or service of a substantive rule shall be made not
less than 30 days before its effective date with certain exceptions,
including (1) for a substantive rule that relieves a restriction or (2)
when the agency finds and provides good cause for foregoing delayed
effectiveness 5 U.S.C. 553(d)(1) and (d)(3). Here, the issuance of
regulations under section 101(a)(5)(A) of the MMPA is a substantive
action that relieves the statutory prohibition on the taking of marine
mammals, specifically, the incidental taking of marine mammals
associated with Hilcorp's specified activities. Until the effective
date of these regulations, Hilcorp is prohibited from taking marine
mammals incidental to their specified activities.
The Assistant Administrator has also determined that there is good
cause under the APA (5 U.S.C. 553(d)(3)) to waive the 30-day delay in
the effective date of this final rule. No individual or entity, other
than Hilcorp, is affected by the provisions of these regulations, and
Hilcorp does not require 30 days to prepare for implementation of the
regulations. Hilcorp has been conducting vessel activities identical to
those described in this final rule for several years, and incidental
take of marine mammals from these activities was most recently
authorized under an IHA that was effective from September 24, 2024,
through September 23, 2025, with similar requirements to those
promulgated herein (<a href="https://www.fisheries.noaa.gov/action/incidental-take-authorization-hilcorp-alaska-llcs-production-drilling-support-activities">https://www.fisheries.noaa.gov/action/incidental-take-authorization-hilcorp-alaska-llcs-production-drilling-support-activities</a>). Hilcorp has informed NMFS that they request that this
final rule take effect as soon as possible to minimize the time without
an MMPA incidental take authorization and avoid any potential
disruption of Hilcorp's planned activities. For these reasons, NMFS
finds good cause to waive the 30-day delay in the effective date.
Classification
Executive Order 12866
The Office of Management and Budget (OMB) has determined that this
final rule is significant for purposes of Executive Order 12866.
Hilcorp's planned activities are a continuation of previously conducted
activities that would support oil and gas exploration, development,
production, and decommissioning in Cook Inlet, Alaska, over the course
of 5 years. The activities would create economic benefits by allowing
oil and gas to come to market more efficiently.
Hilcorp initiated the request for an MMPA incidental take
authorization, which suggests that the company is relying on NMFS'
authorization to proceed with its proposed action. While a MMPA
incidental take authorization is not a pre-condition for conducting the
proposed action (Hilcorp is ultimately responsible for this decision),
it would provide Hilcorp with two key benefits: (1) a legal exemption
from the MMPA's general prohibition on the take of marine mammals
(assuming Hilcorp complies with the terms and conditions of its
authorization); and (2) regulatory certainty because Hilcorp will be
fully cognizant of NMFS' expectations in regard to the steps needed to
be taken to address risks to marine mammals and how to minimize its
legal exposure under the statute. Hilcorp will also incur costs to
comply with certain mitigation and monitoring requirements, as required
by the MMPA. Despite the additional costs of such measures, the costs
related to MMPA compliance during Hilcorp's activities are small
compared with expenditures on other aspects of construction and
operations, and direct compliance costs of the regulatory requirements
are unlikely to result in material impacts to the project.
In addition, cost savings may be generated by the reduced
administrative effort required to obtain a LOA under the framework
established by a rule compared to what would be required to obtain
annual incidental harassment authorizations (IHA) under section
101(a)(5)(D). Absent the rule, to attain equivalent compliance with the
MMPA, Hilcorp would need to apply for IHAs annually over the duration
of their activities. Although not monetized, NMFS' analysis indicates
that the upfront work associated with the rule (e.g., analyses,
modeling, process for obtaining an LOA valid for 5 years) likely saves
significant time and money for both NMFS and Hilcorp.
The rule also results in certain non-monetized benefits. Should
Hilcorp proceed with the project, the protection of marine mammals
afforded by this rule may benefit the regional economy via tourism and
recreation to some extent. Marine mammals within Cook Inlet that
overlap with the proposed action are likely to benefit from the suite
of mitigation and monitoring measures required by the rule, thereby
helping to
[[Page 8141]]
ensure their long-term survival and their contribution to tourism and
other recreational activities in the region.
In addition, some degree of benefits can be expected to accrue
solely via ecological benefits to marine mammals and other wildlife as
a result of this rulemaking. The published literature is clear that
healthy populations of marine mammals and other co-existing species
benefit regional economies and provide social welfare benefits to
people. However, the literature does not provide a basis for
quantitatively valuing the cost of anticipated incremental changes in
environmental disturbance and marine mammal harassment associated with
the rule.
Executive Order 14192
This rule is an Executive Order 14192 deregulatory action. The
promulgation of incidental take regulations under MMPA section
101(a)(5)(A), as requested by applicants, is deregulatory because
issuance allows an otherwise prohibited action (i.e., the incidental
taking of marine mammals) to proceed. The regulations increase
flexibility and reduce burden by allowing for authorization of
otherwise prohibited marine mammal take.
Regulatory Flexibility Act
Pursuant to section 605(b) of the Regulatory Flexibility Act (RFA)
(5 U.S.C. 601 et seq.), at the proposed rule stage the Chief Counsel
for Regulation of the Department of Commerce certified to the Chief
Counsel for Advocacy of the Small Business Administration that this
final rule would not have a significant economic impact on a
substantial number of small entities. As described in the proposed
rule, Hilcorp is the only entity that would be subject to the
requirements in these proposed regulations. Hilcorp employs thousands
of people worldwide and has a market value in the billions of dollars.
Therefore, Hilcorp is not a small governmental jurisdiction, small
organization, or small business as defined by the RFA. No comments on
the certification have been received, and no new information has been
identified to change this conclusion. Therefore, a regulatory
flexibility analysis is not required, and none has been prepared.
Paperwork Reduction Act
This rule contains collection-of-information requirements subject
to the provisions of the PRA. These requirements have been approved by
OMB under control number 0648-0151 ``Applications and Reporting
Requirements for the Incidental Take of Marine Mammals by Specified
Activities Under the Marine Mammal Protection Act'' and include the
applications for regulations, subsequent LOAs, and reports.
Notwithstanding any other provision of law, no person is required to
respond to nor shall a person be subject to a penalty for failure to
comply with a collection of information subject to the requirements of
the PRA unless that collection of information displays a currently
valid OMB control number.
The current information collection approved by OMB under control
number 0648-0151 includes burden estimates for incidental take
authorizations issued under the MMPA. The current numbers approved
under 0648-0151 are as follows: 576 respondents, 576 responses, 70,236
burden hours, and $2,892,557 in labor and miscellaneous costs. This
current rulemaking is expected to result in the following burden
estimates; 1 respondent, 13 responses, and 9,302 burden hours, $136,823
in labor and miscellaneous costs. The burden hours in this rule fall
within the existing burden estimates associated with this control
number.
List of Subjects in 50 CFR Part 217
Acoustics, Alaska, Administrative practice and procedure,
Endangered and threatened species, Fish, Marine mammals, Mitigation and
monitoring requirements, Oil and Gas exploration, Reporting
requirements, Transportation, Wildlife.
Dated: February 17, 2026.
Sarah Malloy,
Acting Deputy Assistant Administrator for Regulatory Programs, National
Marine Fisheries Service.
For reasons set forth in the preamble, NMFS amends 50 CFR part 217
to read as follows:
PART 217--REGULATIONS GOVERNING THE TAKE OF MARINE MAMMALS
INCIDENTAL TO SPECIFIED ACTIVITIES
0
1. The authority citation for part 217 continues to read as follows:
Authority: 16 U.S.C. 1361 et seq., unless otherwise noted.
0
2. Add subpart Q, consisting of Sec. Sec. 217.160 through 217.169, to
read as follows:
Subpart Q--Taking Marine Mammals Incidental to Hilcorp Alaska, LLC Oil
and Gas Activities in Cook Inlet, Alaska
Sec.
217.160 Specified activity and specified geographical region.
217.161 Effective dates.
217.162 Permissible methods of taking.
217.163 Prohibitions.
217.164 Mitigation requirements.
217.165 Requirements for monitoring and reporting.
217.166 Letters of authorization.
217.167 Modifications of letters of authorization.
217.168-217.169 [Reserved]
Subpart Q--Taking Marine Mammals Incidental to Hilcorp Alaska, LLC
Oil and Gas Activities in Cook Inlet, Alaska
Sec. 217.160 Specified activity and specified geographical region.
(a) Regulations in this subpart apply only to Hilcorp Alaska LLC
(Hilcorp) and those persons it authorizes or funds to conduct
activities on its behalf for the taking of marine mammals in Cook
Inlet, Alaska, and that occurs incidental to the activities described
in paragraph (c) of this section. Requirements imposed on Hilcorp must
be implemented by those persons it authorizes or funds to conduct
activities on its behalf.
(b) The incidental taking of marine mammals by Hilcorp may be
authorized in a letter of authorization (LOA) only if it occurs within
in Cook Inlet, Alaska.
(c) The taking of marine mammals by Hilcorp is only authorized if
it occurs incidental to the use of tugs towing, holding, or positioning
a jack-up rig, impact pile driving, and pipeline installation and/or
replacement involving anchor handling and/or pipe pulling.
Sec. 217.161 Effective dates.
Regulations in this subpart are effective from February 20, 2026,
through February 19, 2031.
Sec. 217.162 Permissible methods of taking.
Under an LOA issued pursuant to Sec. Sec. 217.106 of this chapter
and 217.166, the holder of the LOA (hereinafter ``Hilcorp'') may
incidentally, but not intentionally, take marine mammals within the
specified geographical region described in Sec. 217.160(b) by
harassment associated with the specified activities provided they are
in compliance with all terms, conditions, and requirements of the
regulations in this subpart and the applicable LOA.
Sec. 217.163 Prohibitions.
Except for the takings permitted in Sec. 217.162 and authorized by
an LOA issued under Sec. Sec. 216.106 of this chapter and 217.166, it
is unlawful for any person to do any of the following in connection
with the specified activities:
(a) Violate or fail to comply with the terms, conditions, and
requirements of this subpart or an LOA issued under
[[Page 8142]]
this subpart or an LOA issued under Sec. Sec. 216.106 of this chapter
and 217.166;
(b) Take any marine mammal not specified in such LOA;
(c) Take any marine mammal specified in such LOA in any manner
other than specified;
(d) Take a marine mammal should NMFS withdraw or suspend such LOA;
or
(e) Take a marine mammal specified in such LOA after NMFS
determines such taking results in an unmitigable adverse impact on the
species or stock of such marine mammal for taking for subsistence uses.
Sec. 217.164 Mitigation requirements.
When conducting the specified activities identified in Sec.
217.160(c), Hilcorp must implement the mitigation measures contained in
this section and any LOA issued under Sec. Sec. 216.106 of this
chapter and 217.166 unless implementing the mitigation measure would
create a risk to human safety or cause pile instability or refusal.
These mitigation measures include, but are not limited to:
(a) A copy of any issued LOA should be in the possession of
Hilcorp, its designees, and work crew personnel operating under the
authority of the issued LOA.
(b) Hilcorp must coordinate with local Tribes as described in its
Stakeholder Engagement Plan, notify the communities of any changes in
the operation, and take action to avoid or mitigate impacts to
subsistence harvests.
(c) Tug boat and pile driving supervisors and crews, the monitoring
team, and relevant Hilcorp staff must be trained prior to the start of
all activities so that responsibilities, communication procedures,
mitigation measures, monitoring protocols, and operational procedures
are clearly understood. New personnel joining during the project must
be trained prior to commencing work.
(d) Hilcorp must implement clearance and shutdown zones with radial
distances as identified in any LOA issued under Sec. Sec. 216.106 of
this chapter and 217.166.
(e) Pre-start clearance monitoring.
(1) Prior to initiating any activity or resuming those activities
after a 30-minute lapse (e.g., pauses between intermittent pile
driving), Hilcorp must conduct monitoring of the clearance zones 30
minutes prior to commencing activities identified in Sec. 217.160(c)
(i.e., pre-start clearance monitoring).
(2) Except for tugs towing a jack-up rig, activities may commence
or resume if, following 30 minutes of observation of the clearance
zone, it is determined by a protected species observer (PSO) that the
clearance zones are clear of marine mammals.
(3) Should a marine mammal be within the clearance zone during the
clearance monitoring period, the activity (except for tugs under tow if
tidal restrictions necessitate) must not commence or resume until any
animal has left the clearance zone and is on a path away from the
clearance zone or at least 30 minutes has elapsed for all baleen whale
species and Cook Inlet Beluga Whales (CIBWs) without subsequent
detection, or 15 minutes has elapsed without subsequent detection for
all other species.
(f) Pile driving at the Tyonek Platform may only occur from
November 15 through April 15.
(g) Hilcorp must cease all pile driving activities, including soft
starts, if a marine mammal is observed entering or within the shutdown
zone. Should safety or pile instability or refusal concerns prevent a
shutdown, pile driving may continue only until the current segment of
the pile is driven; no additional sections of pile or additional piles
may be driven until a PSO has determined that the clearance zones are
clear of marine mammals.
(1) If pile driving is halted or delayed due to the presence of a
marine mammal, the activity may not commence or resume until either the
animal has voluntarily left and is visually confirmed to be beyond the
shutdown zone or at least 30 minutes has elapsed for all baleen whale
species and CIBWs without subsequent detection or 15 minutes has
elapsed without subsequent detection for all other species.
(2) If during pile driving, a PSO can no longer effectively monitor
the entirety of the corresponding shutdown zone due to environmental
conditions (e.g., fog, rain, wind), pile driving may continue only
until the current segment of the pile is driven. No additional sections
of pile or additional piles may be driven until conditions improve such
that the shutdown zone can be effectively monitored. If the shutdown
zone cannot be monitored for more than 15 minutes, the entire zone must
be cleared again for 30 minutes prior to reinitiating pile driving.
(h) Hilcorp must use soft-start techniques when impact pile
driving. Should safety or pile instability/refusal concerns arise
during a soft start wherein this process cannot be met, Hilcorp must
use the minimum amount of energy practicable. Prior to soft-start
beginning, the operator must receive confirmation from the PSO that the
clearance zone is clear of any marine mammals.
(i) For transportation of a jack-up rig to or from the Tyonek
platform, in addition to PSOs stationed on the rig during towing, an
additional PSO must be stationed on the Tyonek Platform to monitor for
marine mammals. The PSO should be on watch for at least 1 hour before
tugs are expected to arrive (scheduled to approach the estimated 120-dB
isopleth).
(j) Unless deviation is necessary to maintain safe maneuvering
speed and justified because the vessel is in an area where
oceanographic, hydrographic, and/or meteorological conditions severely
restrict the maneuverability of the vessel; an emergency situation
presents a threat to the health, safety, life of a person; or a vessel
is actively engaged in emergency rescue or response duties, including
vessel-in-distress or environmental crisis response, Hilcorp must:
(1) Maneuver tugs engaged in towing, holding, or positioning a
jack-up rig, and anchor handling and pipe pulling activities such that
they maintain a consistent speed (approximately 4 knots [kt; 7
kilometers (km)/hr]) and avoid multiple changes of speed and direction
to make the course of the vessels as predictable as possible to marine
mammals in the surrounding environment, characteristics that are
expected to be associated with a lower likelihood of disturbance;
(2) Not actively approach a marine mammal purposefully and must
adhere to NOAA Alaska Region Marine Mammal Viewing Guidelines;
(3) Reduce vessel speed to < 9 km/hr (5 kt) when within 274 meters
(m; 300 yards) of any whale, reduce speed to 18.5 km/hr (10 kt) or less
when weather conditions reduce visibility to 1.6 km (1 mile [mi]) or
less, avoid multiple changes in direction and speed when within 274 m
(300 yards) of any whale, and place the engine in neutral if a whale is
approaching within 91 m (100 yards) of a vessel;
(4) Maintain a distance of at least 2.4 km from the Mean Lower Low
Water line of the Susitna River Delta (Beluga River to the Little
Susitna River) between April 15 and November 15; and
(5) Maintain a watch for marine mammals while underway and check
water immediately adjacent to the vessel prior to engaging propellers;
should a marine mammal be observed near propellers and it is determined
that interaction is possible, delay engaging propellers.
(k) Hilcorp must maintain clean, taught lines in the water such
that no lines are in the water unless both ends
[[Page 8143]]
are under tension and affixed to vessels or gear.
Sec. 217.165 Requirements for monitoring and reporting.
Hilcorp must implement the following monitoring and reporting
measures:
(a) Monitoring must be conducted by NMFS-approved PSOs during all
activities for which take is authorized, in accordance with Hilcorp's
Marine Mammal Monitoring and Mitigation Plan (which is included in
appendix A of Hilcorp's application). PSOs must be independent of the
activity contractor (e.g., employed by a subcontractor) and have no
other assigned tasks during monitoring duties.
(b) A lead PSO must be designated for all specified activities. The
lead PSO must have prior experience performing the duties of a PSO
during in-water activities pursuant to a NMFS-issued incidental take
authorization or letter of concurrence.
(c) PSOs must monitor for marine mammals from the best available
vantage point, ideally an elevated stable platform from which the PSO
has an unobstructed 360-degree view of the water or a total 360-degree
view of water between all PSOs on watch. Monitoring must occur from 30
minutes before an activity commences to 30 minutes after the activity
ceases.
(d) PSOs must use a combination of equipment to scan the
appropriate monitoring area and to identify the relevant mitigation
distance from an activity, including the naked eye, binoculars (minimum
7x50), and night vision devices for low light and nighttime operations.
(e) PSOs must be in communication with all rig or vessel captains
via VHF radio and/or cell phones at all times and alert rig or vessel
captains to all marine mammal sightings relative to the vessel
location.
(f) PSOs may not work in shifts lasting more than 4 hours without a
minimum of 1-hour break and may not be on watch more than 12 hours in a
24-hour period.
(g) Hilcorp must notify NMFS Office of Protected Resources (OPR) at
least 48 hours prior to the start of the specified activities each
year.
(h) Hilcorp must submit interim monthly monitoring reports on the
15th day of the month after any specified activities occurred. These
reports must include a summary of marine mammal species and behavioral
observations, delays, shutdowns, and activities completed during the
reporting period. The reports also must include an assessment of the
amount of work remaining for the year, in addition to the number of
CIBWs observed within estimated Level B harassment zones during
activities to date, and any instances where mitigation could not be
implemented due to safety or pile instability/refusal concerns.
(i) Hilcorp must submit a draft annual summary monitoring report on
all monitoring conducted during each project year which includes final
electronic data sheets within 90 calendar days of the completion of
marine mammal monitoring or 90 days prior to a requested date of
issuance of any future incidental take authorization for projects at
the same location, whichever comes first. A draft comprehensive 5-year
summary report must also be submitted to NMFS within 90 days of the end
of year 5 of the project. The reports must detail the monitoring
protocol and summarize the data recorded during monitoring. If no
comments are received from NMFS within 30 days of receipt of the draft
reports, the report may be considered final. If comments are received,
revised reports addressing NMFS comments must be submitted within 30
days after receipt of comments. At a minimum, the reports must contain:
(1) Dates and times (begin and end) of all marine mammal
monitoring;
(2) Activities occurring during each daily observation period,
including the type of activity (tugs under load with a jack-up rig,
pile driving, anchor handling, pipe pulling), the total duration of
each type of activity, when nighttime operations occurred (and if they
did, whether night vision devices (NVDs) were employed, including which
lenses were utilized), and whether towing against the tide was
required;
(3) PSO locations during marine mammal monitoring;
(4) Environmental conditions during monitoring periods (at
beginning and end of PSO shift and whenever conditions change
significantly), Beaufort sea state, and any other relevant weather
conditions including cloud cover, fog, sun glare, and overall
visibility to the horizon, and estimated observable distance; and
(5) Upon observation of a marine mammal, the following information
must be collected and included in the annual and 5-year reports:
(i) Name of the PSO who sighted the animal, observer location, and
activity at time of sighting;
(ii) Time of sighting;
(iii) Identification of the animal (e.g., genus/species, lowest
possible taxonomic level, or unidentified), PSO confidence in
identification, and the composition of the group if there is a mix of
species;
(iv) Distances and bearings of each marine mammal observed in
relation to the vessel (e.g., tug, pipe lay barge) or pile being driven
for each sighting (if pile driving was occurring at time of sighting);
(v) Estimated number of animals (min/max/best);
(vi) Estimated number of animals by cohort (adults, juveniles,
neonates, group composition, etc.);
(vii) Animal's closest point of approach and estimated time spent
within the harassment zone;
(viii) Description of any marine mammal behavioral observations
(e.g., observed behaviors such as feeding or traveling), including an
assessment of behavioral responses to the activity (e.g., no response
or changes in behavioral state such as ceasing feeding, changing
direction, flushing, or breaching);
(ix) Detailed information about any implementation of any
mitigation (e.g., shutdowns and delays), a description of specific
actions that ensued, and resulting changes in the behavior of the
animal, if any;
(x) All PSO datasheets and raw sightings data in electronic
spreadsheet format; and
(xi) Any instances where mitigation could not be implemented due to
safety or pile instability/refusal concerns.
(j) In the event that personnel involved in Hilcorp's activities
discover an injured or dead marine mammal, Hilcorp must report the
incident to NMFS OPR and the Alaska Regional Stranding Network as soon
as feasible. If the death or injury was caused by a specified activity,
Hilcorp must immediately cease the specified activity until NMFS is
able to review the circumstances of the incident and determine what, if
any, additional measures are appropriate to ensure compliance with the
LOA. Hilcorp must not resume their activities until notified by NMFS.
The report must include the following information:
(1) Time, date, and location (latitude/longitude) of the first
discovery (and updated location information if known and applicable);
(2) Species identification (if known) or description of the
animal(s) involved;
(3) Condition of the animal(s) (including carcass condition if the
animal is dead);
(4) Observed behaviors of the animal(s), if alive;
(5) If available, photographs or video footage of the animal(s);
and
(6) General circumstances under which the animal was discovered.
[[Page 8144]]
Sec. 217.166 Letters of authorization.
(a) To incidentally take marine mammals pursuant to this subpart,
Hilcorp must apply for and obtain an LOA.
(b) An LOA, unless suspended or revoked, may be effective for a
period of time not to exceed the effective dates of this subpart in
Sec. 217.161.
(c) In the event Hilcorp proposes projected changes to the activity
or to mitigation and monitoring measures required by an LOA, Hilcorp
must request and obtain a modification of the LOA as described in Sec.
217.167.
(d) The LOA must set forth the following information:
(1) Permissible methods of incidental taking;
(2) Means of effecting the least practicable adverse impact (i.e.,
mitigation) on the species, its habitat, and on the availability of the
species for subsistence uses; and
(3) Requirements for monitoring and reporting.
(e) Issuance of the LOA should be based on a determination that the
level of taking will be consistent with the findings made for the total
taking allowable under this subpart.
(f) Notice of issuance or denial of an LOA should be published in
the Federal Register within 30 days of a determination.
Sec. 217.167 Modifications of letters of authorization.
(a) An LOA issued under Sec. Sec. 216.106 of this chapter and
217.166 for the specified activities may be modified upon request by
Hilcorp, provided that:
(1) The changes to the activity or the mitigation, monitoring, or
reporting does not change the findings made pursuant to this subpart
and do not result in more than a minor change in the total estimated
number of takes (or distribution by species or stock or years); and
(2) NMFS determines that Hilcorp implemented the mitigation,
monitoring, and reporting measures required by the LOA for which
modification is requested.
(b) An LOA issued under Sec. Sec. 216.106 of this chapter and
217.166 may be modified at NMFS' initiation if:
(1) Doing so creates a reasonable likelihood of more effectively
accomplishing the goals of the mitigation and monitoring measures; or
(2) NMFS determines that an emergency exists that poses a
significant risk to the well-being of the species or stocks of marine
mammals specified in an LOA issued pursuant to Sec. Sec. 216.106 of
this chapter and 217.166, in which case, the LOA may be modified
without prior notice or opportunity for public comment; however,
notification will be published in the Federal Register within 30 days
of the action.
(c) If the modifications to the specified activities, mitigation,
monitoring, or reporting measures are substantial, NMFS shall publish a
notice of proposed LOA in the Federal Register and solicit public
comment prior to making a determination on issuance.
(d) Possible sources of data that could contribute to a decision to
modify the LOA include, but are not limited to:
(1) Results from Hilcorp's monitoring;
(2) Results from other marine mammal and/or sound research or
studies; and
(3) Any information that reveals marine mammals may have been taken
in a manner, extent or number not authorized by this subpart or
subsequent LOAs.
Sec. Sec. 217.168-217.169 [Reserved]
[FR Doc. 2026-03375 Filed 2-19-26; 8:45 am]
BILLING CODE 3510-22-P
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</html>Indexed from Federal Register on February 20, 2026.
This is legal information, not legal advice. Laws vary by jurisdiction and change frequently. Always verify current law with official sources and consult a licensed attorney in your jurisdiction for advice on your specific situation.