Marine Mammals; Incidental Take During Specified Activities; Proposed Incidental Harassment Authorization for the Southern Beaufort Sea Stock of Polar Bears on the North Slope of Alaska, 88943-88961 [2023-28428]

Agencies

• Fish and Wildlife Service
• DEPARTMENT OF THE INTERIOR

[Federal Register Volume 88, Number 246 (Tuesday, December 26, 2023)]
[Notices]
[Pages 88943-88961]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2023-28428]


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DEPARTMENT OF THE INTERIOR

Fish and Wildlife Service

[Docket No. FWS-R7-ES-2023-0209; FXES111607MRG01-245-FF07CAMM00]


Marine Mammals; Incidental Take During Specified Activities; 
Proposed Incidental Harassment Authorization for the Southern Beaufort 
Sea Stock of Polar Bears on the North Slope of Alaska

AGENCY: Fish and Wildlife Service, Interior.

ACTION: Notice of receipt of application; proposed incidental 
harassment authorization; notice of availability of draft environmental 
assessment; request for comments.

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SUMMARY: We, the U.S. Fish and Wildlife Service, in response to a 
request under the Marine Mammal Protection Act of 1972, as amended, 
from the Bureau of Land Management, propose to authorize nonlethal 
incidental take by harassment of small numbers of Southern Beaufort Sea 
(SBS) polar bears (Ursus maritimus) for 1 year from the date of 
issuance. The applicant requested this authorization for take by 
harassment that may result from activities associated with oil well 
plugging and reclamation, soil sampling, snow trail, pad, and airstrip 
construction, and summer cleanup activities in the North Slope Borough 
of Alaska between the Wainwright and Oliktok Areas. This proposed 
authorization, if finalized, will be for up to 18 takes of polar bears 
by Level B harassment and up to 3 takes of polar bears by non-serious 
Level A harassment. No serious Level A or lethal take is requested, 
expected, or proposed to be authorized.

DATES: Comments on this proposed incidental harassment authorization 
and the accompanying draft environmental assessment must be received by 
January 25, 2024.

ADDRESSES: Document availability: You may view this proposed incidental 
harassment authorization, the application package, supporting 
information, draft environmental assessment, and the list of references 
cited herein at https://www.regulations.gov under Docket No. FWS-R7-ES-
2023-0209. Alternatively, you may request these documents from the 
person listed under FOR FURTHER INFORMATION CONTACT.
    Comment submission: You may submit comments on the proposed 
authorization by one of the following methods:

[[Page 88944]]

     U.S. mail: Public Comments Processing, Attn: Docket No. 
FWS-R7-ES-2023-0209, U.S. Fish and Wildlife Service, MS: PRB (JAO/3W), 
5275 Leesburg Pike, Falls Church, VA 22041-3803.
     Electronic submission:
    https://www.regulations.gov. Follow the instructions for submitting 
comments to Docket No. FWS-R7-ES-2023-0209.
    We will post all comments at https://www.regulations.gov. You may 
request that we withhold personal identifying information from public 
review; however, we cannot guarantee that we will be able to do so. See 
Request for Public Comments for more information.

FOR FURTHER INFORMATION CONTACT: Charles Hamilton, by email at 
[email protected], by telephone at 1-800-362-5148, or by U.S. 
mail at U.S. Fish and Wildlife Service, MS 341, 1011 East Tudor Road, 
Anchorage, Alaska 99503. Individuals in the United States who are deaf, 
deafblind, hard of hearing, or have a speech disability may dial 711 
(TTY, TDD, or TeleBraille) to access telecommunications relay services. 
Individuals outside the United States should use the relay services 
offered within their country to make international calls to the point-
of-contact in the United States.

SUPPLEMENTARY INFORMATION: 

Background

    Section 101(a)(5)(D) of the Marine Mammal Protection Act of 1972 
(MMPA; 16 U.S.C. 1361, et seq.) authorizes the Secretary of the 
Interior (Secretary) to allow, upon request, the incidental, but not 
intentional, taking by harassment of small numbers of marine mammals in 
response to requests by U.S. citizens (as defined in title 50 of the 
Code of Federal Regulations (CFR) in part 18, at 50 CFR 18.27(c)) 
engaged in a specified activity (other than commercial fishing) in a 
specified geographic region during a period of not more than 1 year. 
The Secretary has delegated authority for implementation of the MMPA to 
the U.S. Fish and Wildlife Service (Service or we). According to the 
MMPA, the Service shall allow this incidental taking by harassment if 
we make findings that the total of such taking for the 1-year period:
    (1) is of small numbers of marine mammals of a species or stock;
    (2) will have a negligible impact on such species or stocks; and
    (3) will not have an unmitigable adverse impact on the availability 
of the species or stock for taking for subsistence use by Alaska 
Natives.
    If the requisite findings are made, we issue an authorization that 
sets forth the following, where applicable:
    (a) permissible methods of taking;
    (b) means of effecting the least practicable adverse impact on the 
species or stock and its habitat and the availability of the species or 
stock for subsistence uses; and
    (c) requirements for monitoring and reporting of such taking by 
harassment, including, in certain circumstances, requirements for the 
independent peer review of proposed monitoring plans or other research 
proposals.
    The term ``take'' means to harass, hunt, capture, or kill, or 
attempt to harass, hunt, capture, or kill any marine mammal. 
``Harassment'' for activities other than military readiness activities 
or scientific research conducted by or on behalf of the Federal 
Government means any act of pursuit, torment, or annoyance which (i) 
has the potential to injure a marine mammal or marine mammal stock in 
the wild (the MMPA defines this as ``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 (the MMPA defines this as ``Level B harassment'').
    The terms ``negligible impact'' and ``unmitigable adverse impact'' 
are defined in 50 CFR 18.27 (i.e., regulations governing small takes of 
marine mammals incidental to specified activities) as follows: 
``Negligible impact'' is 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. ``Unmitigable adverse impact'' 
means 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.
    The term ``small numbers'' is also defined in 50 CFR 18.27. 
However, we do not rely on that definition here as it conflates ``small 
numbers'' with ``negligible impacts.'' We recognize ``small numbers'' 
and ``negligible impacts'' as two separate and distinct requirements 
when reviewing requests for incidental harassment authorizations (IHA) 
under the MMPA (see Natural Res. Def. Council, Inc. v. Evans, 232 F. 
Supp. 2d 1003, 1025 (N.D. Cal. 2003)). Instead, for our small numbers 
determination, we estimate the likely number of marine mammals to be 
taken and evaluate if that number is small relative to the size of the 
species or stock.
    The term ``least practicable adverse impact'' is not defined in the 
MMPA or its enacting regulations. For this IHA, we ensure the least 
practicable adverse impact by requiring mitigation measures that are 
effective in reducing the impact of specified activities, but they are 
not so restrictive as to make specified activities unduly burdensome or 
impossible to undertake and complete.
    If the requisite findings are made, we shall issue an IHA, which 
may set forth the following, where applicable: (i) permissible methods 
of taking; (ii) other means of effecting the least practicable impact 
on the species or stock and its habitat, paying particular attention to 
rookeries, mating grounds, and areas of similar significance, and on 
the availability of the species or stock for taking for subsistence 
uses by coastal-dwelling Alaska Natives (if applicable); and (iii) 
requirements for monitoring and reporting take by harassment.

Summary of Request

    On May 22, 2023, the Service received a request from the Department 
of the Interior's Bureau of Land Management (BLM) for authorization to 
take by nonlethal incidental harassment small numbers of Southern 
Beaufort Sea (SBS) polar bears (Ursus maritimus) during oil well 
plugging and reclamation, soil sampling, snow trail, pad, and runway 
construction, and summer cleanup activities in the North Slope Borough 
of Alaska between the Wainwright and Oliktok Areas, for a period of 1 
year from the date of issuance and beginning during the winter of 2023/
2024. Their request also included a proposed Polar Bear Awareness and 
Interaction Plan. The Service requested further information on June 8, 
June 16, July 10, August 7, September 15, and September 19, 2023. BLM 
submitted clarifying information on June 26, July 18, August 10, 
September 20, and October 5, 2023. The Service received a revised 
application on October 5, 2023. The Service deemed the revised request 
dated September 2023 (received October 5, 2023; hereafter referred to 
as the ``Request''), adequate and complete on October 5, 2023.

[[Page 88945]]

Description of Specified Activities and Specified Geographic Region

    The specified activities described in the Request consist of oil 
well plugging and reclamation, soil sampling, snow trail, pad, and 
airstrip construction, and summer cleanup activities in the North Slope 
Borough of Alaska between the Wainwright and Oliktok Areas (figure 1; 
BLM 2023).
[GRAPHIC] [TIFF OMITTED] TN26DE23.001

Maternal Den Surveys

    BLM will conduct two aerial infrared (AIR) maternal den surveys to 
identify any active polar bear dens in the area prior to beginning 
operations within a 2-mile corridor along the northern route from 
Oliktok to the Tulageak well site. The surveyors will use AIR cameras 
on fixed-wing aircraft with flights flown between 245-457 meters (m) 
(800-1,500 feet [ft]) above ground level at a speed of <185 kilometers 
per hour (km/h) (<115 miles per hour [mph]). These surveys will be 
concentrated on areas within 1.6 kilometers (km) (1 mile [mi]) of 
project activities that would be suitable for polar bear denning 
activity such as drainages, banks, bluffs, or other areas of 
topographic relief. The first survey will be conducted between December 
1 and 25, 2023, and the second survey will be conducted between 
December 15, 2023, and January 10, 2024, with a minimum of 24 hours 
between surveys.

Snow Trail, Pad, and Airstrip Construction

    There are no permanent roads available to access any of the three 
legacy wells included in this project; therefore, construction of 
temporary snow trails is required. Snow trail construction will occur 
during January or February of 2024, after ``prepacking'' a minimum of 
15 centimeters (cm) (6 inches [in]) of base snow via all terrain 
smooth-tracked vehicles approved for off-road tundra travel. Prepacking 
promotes lower tundra soil temperatures and accelerates freezing of 
soils prior to use, thereby helping to protect the tundra during snow 
trail and pad grooming, maintenance, and use. Snow will also be packed 
around stream crossings to protect stream banks and vegetation. Exact 
locations may vary up to 1 mile on either side of the center lines 
depicted in figure 1 based on field conditions. This project will 
require the use of up to approximately 1,001 km (622 mi) of 9-m (30-ft) 
wide snow trails; however, some of the trails utilized will include 
annually constructed trail systems such as the North Slope Borough 
Community Winter Access Trail (CWAT; BLM 2023). Snow trail usage will 
cease with the spring thaw (April/May 2024), and the majority of 
cleanup will occur during demobilization at this time. Final stages of 
cleanup and trail inspection will occur by air (see Equipment 
Mobilization, Demobilization, and Summer Clean-up).
    A 610-m (2,000-ft) long by 30-m (100-ft) wide snow airstrip will be 
constructed at the Tulageak well site. No fuel will be stored at the 
airstrip. A 2.4-hectare (ha) (6-acre [ac], 152-m-by-152 m, 500-ft-by-
500-ft) snow pad will be constructed at the Tulageak well site to 
support testing, cleanup, plugging, and other associated activities. 
Small snow pads (approximately 0.2 ha [0.5 ac]) will also be 
constructed to stage materials and equipment for soil-sampling 
activities at the West Dease and East Simpson 1 well sites. No water 
will be used for snow trail, pad, or airstrip construction.

Equipment Mobilization, Demobilization, and Summer Clean-Up

    Large equipment, including mobile camp trailers, drill rigs, along 
with other support equipment and supplies, will be moved to the 
Tulageak, West Dease, or East Simpson 1 well sites from either the 2P 
gravel pads or existing pads at Oliktok (figure 1) based on sea ice and 
other environmental conditions. Equipment will be hauled along snow 
trails by Steiger Tractors, Tucker Sno-Cats, and D-7 Caterpillar 
Tractors. Trips

[[Page 88946]]

to or from Oliktok will take the northern snow trail route, and trips 
from the 2P pad will take the southern snow trail route (figure 1; BLM 
2023). A total of up to 13 round trips could be required between 
January and mid-May 2024, along either or a combination of these 2 
routes including 3-4 round trips during both mobilization (January or 
February) and demobilization (April or early May), and up to 5 round 
trips for resupply during operations.
    Additionally, there are two planned resupply routes from 
Utqia[gdot]vik to the well sites. A 30-mile resupply snow trail will 
follow the Barrow Gas Field Road from Utqia[gdot]vik to the Tulageak 
well site, while a second resupply snow road branches off the CWAT 
south of Utqia[gdot]vik, heading east to the Tulageak project area 
(figure 1). The resupply routes would be used to bring in crews, fuel, 
water, ancillary equipment, and supplies throughout the operations 
period. As with the other routes, Steiger Tractors, Tucker Sno-cats, 
and D-7 Caterpillar Tractors would be used to pull sleds and sleighs on 
the resupply routes. During winter operations, there would be 
approximately one to three round trips every day along the resupply 
routes from Utqia[gdot]vik to the Tulageak well site for fuel, 
personnel, water, and supplies. There would be approximately 36-50 
total round trips on these routes during the winter season. Access 
routes from Wainwright and Atqasuk may also be used to transport crews, 
equipment, and vehicles (with the exception of the drill rigs and camp 
trailers) to Utqia[gdot]vik or the well sites (figure 1). There would 
be up to five to eight round trips expected to occur along these trail 
sections during operations.
    In addition to ground resupply, two to three fixed-wing support 
flights from Deadhorse to the Tulageak snow airstrip will occur over 
the course of 8 weeks (up to 24 flights) during winter project 
activities. The majority of snow trail and camp cleanup, such as trash 
removal and stick-picking, will occur during demobilization in the 
spring of 2024. Trash and other waste generated by camp and routine 
equipment maintenance will be contained appropriately and transported 
to Prudhoe Bay for disposal (BLM 2023).

Camp Setup

    Three mobile camps will be required to provide crew lodging during 
well site activities. A mobile camp of 20-25 trailers will be required 
for the Tulageak well plugging and reclamation. Smaller camps of up to 
10 trailers will be necessary for soil-sampling activities at both the 
West Dease and East Simpson 1 well sites. Generation of potable water 
from snow and disposal of grey water will follow Alaska Department of 
Environmental Conservation guidance and regulation. Further information 
on camp setup is available in BLM's application (BLM 2023).

Tulageak Well Site Surface Debris Removal, Well Plugging, and 
Reclamation

    Removal of surface debris will occur prior to well plugging. The 
amount of debris is expected to be minor because structures, pilings, 
and solid waste were removed in 1981. Any remaining debris is likely to 
consist of scattered scrap metal or wood near the well and may require 
a variety of equipment to fully remove, including excavators, loaders, 
cutting torches, power tools, chainsaws, hand tools, and debris 
containers (e.g., dumpsters for recyclable scrap metal and solid 
waste). Embedded debris that cannot be easily removed will be cut off 
below surface and buried with soil. All surface debris removed from 
site will be contained and transported back to Prudhoe Bay for 
appropriate disposal. In addition to surface debris, a total of 524 
cubic meters (m\3\) (685 cubic yards [yd\3\]) of diesel-contaminated 
soil (total cubic yards based on previous sampling; see application, 
BLM 2023) will be removed preceding any well-plugging activities and 
shipped to an appropriate disposal facility.
    In 1981, at the conclusion of drilling and evaluation operations, 
cement and mechanical plugs were set at a depth of 792 m (2,600 ft) in 
the casing followed by 183 m (600 ft) of mining mud and then the upper 
610 m (2,000 ft) of casing filled with diesel. Well-plugging operations 
will begin by excavating an area of approximately 5-m-by-5-m (15-ft-by-
15-ft) wide and 3 m (10 ft) deep around the well casing. The 610 m 
(2,000 ft) of well casing diesel will be removed using an 
environmentally safe brine solution, sampled, containerized, and 
transported offsite for appropriate hazardous materials disposal, along 
with the 183 m (600 ft) of drilling mud. This plugging activity will 
generate up to 18,930 liters (l) (5,000 gallons [ga]) of fluids and up 
to 24 m\3\ (30 yd\3\) of drilling mud. The fluids and mud will be 
stored in appropriate onsite hazardous waste storage containers and 
transported offsite for disposal (see application for disposal details, 
BLM 2023). Upon removal of diesel and drilling mud, the casing will be 
filled with arctic blend cement in accordance with BLM regulations. 
Once the cement is fully set, the well casing will be cut off at a 
minimum of 3 m (10 ft) below sea level, marked with a welded steel 
marker plate, and the excavation backfilled with soil to sea level.

Soil Sampling

    In addition to the plugging and cleanup activities at the Tulageak 
well site, soil sampling, and site characterization of the West Dease 
and East Simpson 1 well sites will also be conducted to determine the 
type, location, and volume of drilling waste and contaminated soils at 
each location. The sampling will assist in planning future cleanup 
activities at the sites (these specific future cleanup activities are 
not included in this proposed IHA). Samples will be collected from the 
reserve and flare pits, around the wellheads, and where suspected 
drilling wastes or piles of wastes are located. Up to 25 samples will 
be collected at each site using a small track mounted drill following 
Alaska Department of Environmental Conservation site characterization 
requirements. The drill borings will be approximately 10 cm (4 in) in 
diameter and approximately 3 m (10 ft) deep. At both well locations 
(West Dease and East Simpson 1), approximately 25 samples will be 
collected: 12 samples from the reserve pits, 4 from the flare pits, 4 
from the wellheads, and 5 from piles of known or suspected drilling 
waste.

Summer Cleanup

    The majority of snow trail and camp cleanup, such as trash removal 
and stick-picking, will occur during demobilization in the spring of 
2024 (April-May). However, a single A-star or Jet Ranger type 
helicopter will fly the overland snow trail routes and visit each of 
the three legacy well sites for a final inspection and to remove any 
trash or debris potentially missed during demobilization. Summer 
cleanup activities by helicopter will total up to 15 trips with 46 
takeoff and landings.

Description of Marine Mammals in the Specified Geographic Region

    Polar bears are the only species of marine mammal managed by the 
Service likely to be found within the specified geographic region. 
Information on range, stocks, biology, and climate change impacts on 
polar bears can be found in appendix A of the supplemental information 
(available as described above in ADDRESSES).

Potential Impacts of the Specified Activities on Marine Mammals

Surface-Level Impacts on Polar Bears

    Disturbance impacts on polar bears will be influenced by the type, 
duration, intensity, timing, and location of the source of disturbance. 
Disturbance from

[[Page 88947]]

the specified activities would originate primarily from aircraft 
overflights (helicopter and fixed wing), tundra travel, well site 
plugging and reclamation, well site soil sampling, mobilization and 
demobilization, and cleanup activities. The noises, sights, and smells 
produced by these activities could elicit variable responses from polar 
bears, ranging from avoidance to attraction. When disturbed by noise, 
animals may respond behaviorally by walking, running, or swimming away 
from a noise source, or physiologically via increased heart rates or 
hormonal stress responses (Harms et al. 1997, Tempel and Gutierrez 
2003). However, individual response to noise disturbance can be 
influenced by previous interactions, sex, age, and maternal status 
(Anderson and Aars 2008, Dyck and Baydack 2004). Noise and odors could 
also attract polar bears to work areas (Proposed Deterrence Guidelines; 
75 FR 21571, April 26, 2010). Attracting polar bears to these locations 
could result in human-polar bear interactions, unintentional 
harassment, intentional hazing, or possible lethal take in defense of 
human life. This proposed IHA, if finalized, would authorize only the 
nonlethal, incidental, unintentional take of polar bears that may 
result from the specified activities and would require mitigation 
measures to manage attractants in work areas and reduce the risk of 
human-polar bear interactions.

Human-Polar Bear Interactions

    A larger percentage of polar bears are spending more time on land 
during the open-water season, which may increase the risk for human-
polar bear interactions (Atwood et al. 2016, Rode et al. 2022). Polar 
bear interaction plans, personnel training, attractants management, and 
polar bear monitoring are mitigation measures used to reduce human-
polar bear interactions and minimize the risks to humans and polar 
bears when interactions occur. Polar bear interaction plans detail the 
policies and procedures that will be implemented by BLM to avoid 
attracting and interacting with polar bears as well as minimizing 
impacts to the polar bears. Interaction plans also detail how to 
respond to the presence of polar bears, the chain of command and 
communication, and required training for personnel. Efficient 
management of attractants (e.g., human food, garbage) can prevent polar 
bears from associating humans with food, which mitigates the risk of 
human-polar bear interactions (Atwood and Wilder 2021). Information 
gained from monitoring polar bears near industrial infrastructure can 
be useful for better understanding polar bear distribution, behavior, 
and interactions with humans. Technology that may be used to facilitate 
detection and monitoring of polar bears includes bear monitors, closed-
circuit television, video cameras, thermal cameras, radar devices, and 
motion-detection systems. It is possible that human-polar bear 
interactions may occur during the specified activities, and mitigation 
measures, as described in the applicant's Polar Bear Awareness and 
Interaction Plan, will be implemented by BLM to minimize the risk of 
human-polar bear interactions during the specified activities.
    From mid-July to mid-November, SBS stock polar bears can be found 
in large numbers and high densities on barrier islands, along the 
coastline, and in the nearshore waters of the Beaufort Sea, 
particularly on and around Barter and Cross Islands (Wilson et al. 
2017). This distribution leads to a significantly higher number of 
human-polar bear interactions on land and at offshore structures during 
the open-water season than other times of the year.
    On land, most polar bear observations occur within 2 km (1.2 mi) of 
the coastline based on polar bear monitoring reports. Facilities within 
the offshore and coastal areas are more likely to be approached by 
polar bears, and they may act as physical barriers to polar bear 
movements. As polar bears encounter these facilities, the chances for 
human-polar bear interactions increase. However, polar bears have 
frequently been observed crossing existing roads and causeways, and 
they appear to traverse the human-developed areas as easily as the 
undeveloped areas based on monitoring reports.

Effects of Aircraft Overflights on Polar Bears

    Polar bears experience increased noise and visual stimuli when 
fixed-wing aircraft or helicopters fly above them, which may elicit a 
biologically significant behavioral response. Sound frequencies 
produced by aircraft will likely fall within the hearing range of polar 
bears (Nachtigall et al. 2007) and will be audible to polar bears 
during flyovers or when operating in proximity to polar bears. Polar 
bears likely have acute hearing, with previous sensitivities 
demonstrated between 1.4 and 22.5 kilohertz (kHz) (tests were limited 
to 22.5 kHz, Nachtigall et al. 2007). When exposed to high-energy 
sound, this hearing range may become impaired temporarily (called 
temporary threshold shift, or TTS) or permanently (called permanent 
threshold shift, or PTS). Species-specific TTS and PTS thresholds have 
not been established for polar bears at this time, but TTS and PTS 
thresholds have been established for the general group ``other marine 
carnivores'' which includes polar bears (Southall et al. 2019). Through 
a series of systematic modeling procedures and extrapolations, Southall 
et al. (2019) generated modified noise exposure thresholds for both in 
air and underwater sound (table 1).

   Table 1--Temporary Threshold Shift (TTS) and Permanent Threshold Shift (PTS) Thresholds Established by Southall et al. (2019) Through Modeling and
                                        Extrapolation for ``Other Marine Carnivores,'' Which Includes Polar Bears
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                          TTS                                                 PTS
                                                 -------------------------------------------------------------------------------------------------------
                                                                               Impulsive                                           Impulsive
                                                   Non impulsive ------------------------------------  Non impulsive -----------------------------------
                                                                    SELCUM      SELCUM     Peak SPL                     SELCUM      SELCUM     Peak SPL
--------------------------------------------------------------------------------------------------------------------------------------------------------
Air.............................................             157         146         170         177             161         176
Water...........................................             199         188         226         219             203         232
--------------------------------------------------------------------------------------------------------------------------------------------------------
Values are weighted for other marine carnivores' hearing thresholds and given in cumulative sound exposure level (SELCUM dB re 20[micro]Pa in air and
  SELCUM dB re 1 [micro]Pa in water) for impulsive and non-impulsive sounds, and unweighted peak sound pressure level in air (dB re 20[micro]Pa) and
  water (dB 1[micro]Pa) (impulsive sounds only).

    During a Federal Aviation Administration test, test aircraft 
produced sound at all frequencies measured (50 Hz to 10 kHz) (Healy 
1974). At frequencies centered at 5 kHz, jets flying at 300 m (984 ft) 
produced \1/3\

[[Page 88948]]

octave band noise levels of 84 to 124 dB, propeller-driven aircraft 
produced 75 to 90 dB, and helicopters produced 60 to 70 dB (Richardson 
et al. 1995). Thus, the frequency and level of airborne sounds 
typically produced by aircraft is unlikely to cause TTS or PTS unless 
polar bears are very close to the sound source.
    Although neither TTS nor PTS are anticipated during the specified 
activities, impacts from aircraft overflights have the potential to 
elicit biologically significant behavioral responses from polar bears. 
Exposure to aircraft overflights is expected to result in short-term 
behavior changes, such as ceasing to rest, walking, or running, and, 
therefore, has the potential to be energetically costly. Polar bears 
observed during intentional aircraft overflights, conducted to study 
impacts of aircraft on polar bear responses, with an average flight 
altitude of 143 m (469 ft) exhibited biologically meaningful behavioral 
responses during 66.6 percent of aircraft overflights. These behavioral 
responses were significantly correlated with the aircraft's altitude, 
the bear's location (e.g., coastline, barrier island), and the bear's 
activity (Quigley et al. 2022). Polar bears associated with dens 
exhibited various responses when exposed to low-flying aircraft, 
ranging from increased head movement and observation of the disturbance 
to the initiation of rapid movement and/or den abandonment (Larson et 
al. 2020). Aircraft activities can impact polar bears across all 
seasons; however, aircraft have a greater potential to disturb both 
individuals and groups of polar bears on land during the summer and 
fall. These onshore polar bears are primarily fasting or seeking 
alternative terrestrial foods (Cherry et al. 2009, Griffen et al. 
2022), and polar bear responses to aircraft overflights may result in 
metabolic costs to limited energy reserves. To reduce potential 
disturbance of polar bears during aircraft activities, mitigation 
measures, such as minimum flight altitudes over polar bears and their 
frequently used areas and flight restrictions around known polar bear 
aggregations, will be required when safe to perform these operations 
during aircraft activities.

Effects to Denning Polar Bears

    Known polar bear dens around the oilfield and other areas of the 
North Slope, discovered opportunistically and/or during planned surveys 
for tracking marked polar bears and detecting polar bear dens, are 
monitored by the Service. However, these sites are only a small 
percentage of the total active polar bear dens for the SBS stock in any 
given year. Each year, entities conducting operations on the North 
Slope coordinate with the Service to conduct surveys to determine the 
location of their activities relative to known polar bear dens and 
denning habitat. Under past IHAs and ITRs (incidental take 
regulations), operators have been required to avoid known polar bear 
dens by 1.6 km (1 mi). However, an unknown polar bear den may be 
encountered during BLM's activities. In instances, when a previously 
unknown den was discovered in proximity to human activity, the Service 
implemented mitigation measures such as the 1.6-km (1-mi) activity 
exclusion zone around the den and 24-hour monitoring of the den site.
    The responses of denning polar bears to disturbance and the 
consequences of these responses can vary throughout the denning 
process. We divide the denning period into four stages when considering 
impacts of disturbance: den establishment, early denning, late denning, 
and post-emergence; definitions and descriptions are provided by 
Woodruff et al. (2022) and are also located in the 2021-2026 Beaufort 
Sea ITR (86 FR 42982, August 5, 2021).

Impacts of the Specified Activities on Polar Bear Prey Species

    Information on the potential impacts of the specified activities on 
polar bear prey species can be found in the supplemental information to 
this document (available as described above in ADDRESSES).

Estimated Take

Definitions of Incidental Take Under the Marine Mammal Protection Act

    Below we provide definitions of three potential types of take of 
polar bears. The Service does not anticipate and is not authorizing 
lethal take as a part of this IHA; however, the definitions of these 
take types are provided for context and background.
Lethal Take
    Human activity may result in biologically significant impacts to 
polar bears. In the most serious interactions (e.g., vehicle collision, 
running over an unknown den causing its collapse), human actions can 
result in the mortality of polar bears. We also note that, while not 
considered incidental, in situations where there is an imminent threat 
to human life, polar bears may be killed. Additionally, though not 
considered incidental, polar bears have been accidentally killed during 
efforts to deter polar bears from a work area for safety and from 
direct chemical exposure (81 FR 52276, August 5, 2016). Unintentional 
disturbance of a female polar bear by human activity during the denning 
season may cause the female either to abandon her den prematurely with 
cubs or abandon her cubs in the den before the cubs can survive on 
their own. Either scenario may result in the incidental lethal take of 
the cubs.
Level A Harassment
    Human activity may result in the injury of polar bears. Level A 
harassment, for nonmilitary readiness activities, is defined as any act 
of pursuit, torment, or annoyance that has the potential to injure a 
marine mammal or marine mammal stock in the wild. We have divided Level 
A harassment into events that are likely (>50 percent chance) to result 
in the animal's mortality (referred to as ``serious Level A 
harassment'') and events that are not likely (<50 percent chance) to 
result in the animal's mortality (referred to as ``non-serious Level A 
harassment''). Numerous actions can cause take by Level A harassment, 
such as creating a disturbance that separates mothers from dependent 
cubs (Amstrup 2003), inducing early den emergence (Amstrup and Gardner 
1994, Rode et al. 2018), or repeatedly interrupting the nursing or 
resting of cubs to the extent that it impacts the cubs' body condition.
Level B Harassment
    Level B harassment for nonmilitary readiness activities means any 
act of pursuit, torment, or annoyance that 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, feeding, or sheltering. Changes in 
behavior that disrupt biologically significant behaviors or activities 
for the affected animal are indicative of take by Level B harassment 
under the MMPA. Such reactions include, but are not limited to, the 
following:

     Fleeing (running or swimming away from a human or a human 
activity);
     Displaying a stress-related behavior such as jaw or lip-
popping, front leg stomping, vocalizations, circling, intense staring, 
or salivating;
     Abandoning or avoiding preferred movement corridors such 
as ice floes, leads, polynyas, a segment of coastline, or barrier 
islands;
     Using a longer or more difficult route of travel instead 
of the intended path;

[[Page 88949]]

     Interrupting breeding, sheltering, or feeding;
     Moving away at a fast pace (adult) and cubs struggling to 
keep up;
     Temporary, short-term cessation of nursing or resting 
(cubs);
     Ceasing to rest repeatedly or for a prolonged period 
(adults);
     Loss of hunting opportunity due to disturbance of prey; or
     Any interruption in normal denning behavior that does not 
cause injury, den abandonment, or early departure of the female with 
cubs from the den site.
    This list is not meant to encompass all possible behaviors; other 
behavioral responses may be indicative of take by Level B harassment. 
Relatively minor changes in behavior such as the animal raising its 
head or temporarily changing its direction of travel are not likely to 
disrupt biologically important behavioral patterns, and the Service 
does not view such minor changes in behavior as indicative of a take by 
Level B harassment. It is also important to note that eliciting 
behavioral responses that equate to take by Level B harassment 
repeatedly may result in Level A harassment.

Surface Interactions

    We analyzed take by Level B harassment for polar bears that may 
potentially be encountered and impacted during BLM's oil well plugging 
and reclamation, soil sampling, snow trail, pad, and airstrip 
construction, and summer cleanup activities within the specified 
geographic region.
Impact Area
    To assess the area of potential impact from the project activities, 
we calculate the area affected by project activities where harassment 
is possible. We refer to this area as an impact area. Behavioral 
response rates of polar bears to disturbances are highly variable, and 
data to support the relationship between distance to polar bears and 
disturbance is limited. Dyck and Baydack (2004) found sex-based 
differences in the frequencies of vigilance bouts, which involves an 
animal raising its head to visually scan its surroundings, by polar 
bears in the presence of vehicles on the tundra. However, in their 
summary of polar bear behavioral response to ice-breaking vessels in 
the Chukchi Sea, Smultea et al. (2016) found no difference between 
reactions of males, females with cubs, or females without cubs. During 
the Service's coastal aerial surveys, 99 percent of polar bears that 
responded in a way that indicated possible Level B harassment (polar 
bears that were running when detected or began to run or swim in 
response to the aircraft) did so within 1.6 km (1 mi), as measured from 
the ninetieth percentile horizontal detection distance from the flight 
line. Similarly, Andersen and Aars (2008) found that female polar bears 
with cubs (the most conservative group observed) began to walk or run 
away from approaching snowmobiles at a mean distance of 1,534 m (0.95 
mi). Thus, while future research into the reaction of polar bears to 
anthropogenic disturbance may indicate a different zone of potential 
impact is appropriate, the current literature suggests that the 1.6-km 
(1.0-mi) impact area will encompass most polar bear harassment events.

Estimated Harassment

    We estimated Level B harassment using the spatio-temporally 
specific encounter rates and temporally specific harassment rates 
derived in the 2021-2026 Beaufort Sea ITR (86 FR 42982, August 5, 2021) 
in conjunction with the specified project activity information. Some 
portion of SBS bears may occur within the Chukchi Sea at a given time. 
However, the Beaufort Sea ITR rates do not explicitly account for this 
possibility, and the project area for this proposed IHA occurs only 
within the geographical boundary of the SBS subpopulation. Therefore, 
our analyses account only for SBS bears located within the SBS 
subpopulation boundary. Distribution patterns of polar bears along the 
coast of the SBS were estimated in Wilson et al. (2017) by dividing the 
North Slope Coastline into 10 equally sized grids and applying a 
Bayesian hierarchical model based on 14 years of aerial surveys in late 
summer and early fall. Wilson et al. (2017) estimated 140 polar bears 
per week along the coastline (a measurement that included barrier 
islands), however not with uniform distributions. The study found that 
disproportionality high densities of bears occur in grids 6 and 9, 
which contain known large congregating areas such as Kaktovik and Cross 
Island and has required polar bear density correction factors in 
previously issued ITAs. The vast majority of the coastline within the 
project area in this proposed IHA falls within grids 1-4 (although a 
small portion of the project area is located outside of Wilson et al.'s 
(2017) study area near the City of Wainwright). The Wilson et al. 2017 
values for grids 1-4 are similar to those in the North Slope area where 
the 2021-2026 Beaufort Sea ITR (86 FR 42982, August 5, 2021) encounter 
rates were developed; therefore, we believe those values are applicable 
to the project area in this proposed IHA and do not require any 
correction factor for polar bear densities in our analyses.

 Table 2--Definitions of Variables Used in Harassment Estimates of Polar
             Bears on the Coast of the North Slope of Alaska
------------------------------------------------------------------------
                Variable                            Definition
------------------------------------------------------------------------
B......................................  bears encountered in an impact
                                          area for the entire season.
a......................................  coastal exposure area.
a......................................  inland exposure area.
r......................................  occupancy rate.
e......................................  coastal open-water season bear-
                                          encounter rate in bears/
                                          season.
e......................................  coastal ice season bear-
                                          encounter rate in bears/
                                          season.
e......................................  inland open-water season bear-
                                          encounter rate in bears/
                                          season.
e......................................  inland ice season bear-
                                          encounter rate in bears/
                                          season.
t......................................  ice season harassment rate.
t......................................  open-water season harassment
                                          rate.
B......................................  number of estimated Level B
                                          harassment events.
------------------------------------------------------------------------

    Table 2 provides the definition for each variable used in the 
formulas to calculate the number of potential harassment events. The 
variables defined in table 2 were used in a series of formulas to 
estimate the total harassment from surface-level interactions. 
Encounter rates were originally calculated as polar bears encountered 
per square km per season. As a part of their Request, BLM provided the 
Service with digital geospatial files that included the maximum 
expected human occupancy (i.e., rate of occupancy [ro] for each 
individual structure (e.g., snow trails, snow pads) of their specified 
activities for each season of the IHA period. Using the buffer tool in 
ArcGIS, we created a spatial file of a 1.6-km (1-mi) buffer around all 
industrial structures. We binned the structures according to their 
seasonal occupancy rates by rounding them up into tenths (10 percent, 
20 percent, etc.). We determined the impact area of each bin by first 
calculating the area within the buffers of 100 percent occupancy 
locations. We then removed the area of the 100 percent occupancy 
buffers from the project impact area and calculated the area within the 
90 percent occupancy buffers. This iterative process continued until we 
calculated the area within all buffers. The areas of impact were then 
clipped by coastal and inland zone geospatial files to determine the 
coastal areas of impact (ac) and inland areas of impact (ai) for each 
occupancy bin. This

[[Page 88950]]

process was repeated for each season of the project.
    Impact areas were multiplied by the appropriate encounter rate to 
obtain the number of polar bears expected to be encountered in the 
impact area per season (Bes). The equation below (equation 
1) provides an example of the calculation of polar bears encountered in 
the ice season for an impact area in the coastal zone.

Bes = ac * eci
Equation 1

    To generate the number of estimated Level B harassments for each 
area of interest, we multiplied the number of polar bears in the area 
of interest per season by the proportion of the season the area is 
occupied, the rate of occupancy, and the harassment rate (equation 2).

Bt = Bes * Sp * ro * ti
    Equation 2

Aircraft Impacts on Polar Bears

    Polar bears in the project area will likely be exposed to the 
visual and auditory stimulation associated with the applicant's fixed-
wing and helicopter activities; however, these impacts are likely to be 
minimal and short-term. Aircraft activities may cause disruptions in 
the normal behavioral patterns of polar bears as either an auditory or 
visual stimulus, thereby resulting in incidental Level B harassment. 
Mitigation measures, such as minimum flight altitudes over polar bears 
and restrictions on sudden changes to aircraft movements and direction, 
will be required if this authorization is finalized to reduce the 
likelihood that polar bears are disturbed by aircraft.

Estimating Harassment Rates of Aircraft Activities

    We updated the analysis used to estimate aircraft impacts on polar 
bears from the 2021-2026 Beaufort Sea ITR (86 FR 42982, August 5, 2021) 
to include altitude-specific harassment rates. These altitude-specific 
harassment rates were estimated using observational data from fixed-
wing aircraft overflights (Quigley 2022) and helicopter activities 
(Quigley et al. in review). In these studies, aerial searches along the 
northern coast of Alaska between Point Barrow and the western Canadian 
border were flown and polar bears were approached at different 
altitudes. Researchers recorded behavioral changes during these 
approaches and evaluated when and if Level B harassment occurred. Polar 
bears that did not exhibit behavioral changes consistent with 
harassment were then re-approached at progressively lower altitudes, 
reaching as low as 38 m (100 ft). Because polar bears were encountered 
at discrete-valued altitudes that differed by hundreds of feet, the 
actual altitude at which harassment would not occur likely exists 
between the altitude of observed harassment and the lowest altitude at 
which harassment was not observed. We estimated this theoretical 
harassment altitude by calculating the average of the observed 
harassment altitude and lowest non-harassment altitude. Polar bears 
that exhibited a behavioral change consistent with harassment on their 
first approach could potentially have shown this same response if the 
aircraft were at a higher altitude, thus we could not identify an 
altitude at which no harassment would occur due to a lack of a ``non-
harassment'' observation of that polar bear. To avoid negatively 
biasing results by using these altitudes unadjusted, theoretical 
harassment altitudes were estimated using the average theoretical 
altitude of harassment for all observations of an equal or greater 
altitude (i.e., only including polar bears with two or more observed 
altitudes and excluding other polar bears harassed on initial 
approach). Where there were three or fewer observations to make such an 
average, theoretical harassment altitude was estimated as the average 
of 610 m (2,000 ft) and the observed harassment altitude. We chose 610 
m (2,000 ft) because it was the lowest altitude at which no harassment 
was observed by either aircraft type.
    Using the altitude-specific harassment rates, five categories of 
flights were created: takeoffs, landings, low-altitude flights (defined 
as those between 122 m [400 ft] and 305 m [1,000 ft] altitude), mid-
altitude flights (defined as those between 305 m [1,000 ft] and 457 m 
[1,500 ft] altitude), and high-altitude flights (defined as those 
between 457 m [1,500 ft] and 610 m [2,000 ft] altitude). Harassment 
rates were assigned to each of these flight categories using the 
harassment rate for the lowest altitude in the category (e.g., for low-
altitude flights, the harassment rate estimated for 122 m [400 ft] was 
used). This binning method of using the lowest harassment rate in the 
bin allowed our estimates to be inclusive of possible changes in 
altitude due to variable flight conditions (table 3).

 Table 3--Harassment Rates for the Five Categories of Flights for Fixed-
                Wing Aircraft and Helicopter Overflights
------------------------------------------------------------------------
             Flight category                Fixed-wing      Helicopter
------------------------------------------------------------------------
Takeoffs................................            0.89            0.99
Landings................................            0.89            0.99
Low-altitude flights (122-305 m)........            0.56            0.97
Mid-altitude flights (305-457 m)........           0.005            0.14
High-altitude flights (457-610 m).......          <0.001           0.002
------------------------------------------------------------------------
We used the harassment rate associated with 61 m (200 ft) for takeoffs
  and landings.

Estimating Area of Impact for Aircraft Activities

    For each category of the flight path (i.e., takeoff, low-altitude 
travel, mid-altitude travel, high-altitude travel, and landing), we 
calculated an impact area and duration of impact using flight hours or 
flight path information provided in the Request. We used flights logs 
available through www.flightaware.com (FlightAware), a website that 
maintains flight logs in the public domain, to estimate impact areas 
and flight hours for takeoffs and landings. We estimated a takeoff 
distance of 2.41 km (1.5 mi) that would be impacted for 10 minutes. We 
estimated a landing distance of 4.83 km (3 mi) per 305 m (1,000 ft) of 
altitude that would be impacted for 10 minutes per landing. To estimate 
the impact area of traveling segments, we subtracted the takeoff and 
landing areas from the total area of the flight path. The duration of 
impact for traveling flights was either provided in the Request or 
calculated using the length of the flight and estimated flight speeds, 
provided by BLM, of 193 km per hour (120 mi per hour) or 257 km per 
hour (160 mi per hour) for fixed-winged aircraft. Polar bear encounter 
rates vary both spatial and temporally (table 4). We accounted for 
temporal variation by determining if the flight takes place during the 
open-

[[Page 88951]]

water (July 19-November 11) or the ice season (November 12-July 18). 
Spatial variation was accounted for by determining total proportion of 
the flight over coastal or inland zones. The coastal zone is defined as 
the offshore and onshore areas within 2 km (1.2 mi) of the coastline, 
and the inland zone is defined as the onshore area greater than 2 km 
(1.2 mi) from the coastline. Once spatially referenced, all flight 
paths were buffered by 1.6 km (1 mi), which is consistent with aircraft 
surveys conducted by the Service and the U.S. Geological Survey (USGS) 
between August and October during most years from 2000 to 2014 
(Schliebe et al. 2008, Atwood et al. 2015, Wilson et al. 2017). In 
these surveys, 99 percent of groups of polar bears that exhibited 
behavioral responses consistent with Level B harassment were observed 
within 1.6 km (1 mi) of the aircraft.

Table 4--Seasonal polar bear encounter rates by zone, table adapted from
                       2021-2026 Beaufort Sea ITR
                      [86 FR 42982, August 5, 2021]
------------------------------------------------------------------------
 
------------------------------------------------------------------------
                  Coastal Zone Seasonal Encounter Rate
------------------------------------------------------------------------
Ice Season (July 19-November 11) 0.05
 bears/km\2\.
Open-water Season (November 12-July 18)
 1.48 bears/km\2\.
------------------------------------------------------------------------
                   Inland Zone Seasonal Encounter Rate
------------------------------------------------------------------------
Ice Season (July 19-November 11) 0.004
 bears/km\2\.
Open-water Season (November 12-July 18)
 0.005 bears/km\2\.
------------------------------------------------------------------------

    To calculate the total number of Level B harassment events 
estimated due to the specified activities, we calculated the number of 
flight hours for each flight category (i.e., takeoffs, low-altitude 
travel, mid-altitude travel, high-altitude travel, and landings) for 
each zone and season combination. These values were then used to 
calculate the proportion of the season that aircraft occupied their 
impact areas (i.e., takeoff area, landing area, or traveling segment 
impact areas). This proportion-of-season metric is equivalent to the 
occupancy rate (ro) generated for surface-level interaction harassment 
estimates. The total impact area for each of the flight categories was 
multiplied by the zone and season-specific polar bear encounter rate to 
determine the number of polar bears expected in that area for the 
season (i.e., Bes, as seen in equation 1). This number was then 
multiplied by the proportion of the season to determine the number of 
polar bears expected in that area when flights are occurring, and the 
appropriate harassment rate based on flight altitude to estimate the 
number of polar bears that may be harassed as a result of the flights 
(as seen in equation 2). Table 5 shows a summary of aircraft operations 
during the specified activities and the values used to estimate Level B 
harassment of polar bears during aircraft operations.

                              Table 5--Summary of Aircraft Operations by Season and Activity During the Proposed IHA Period
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                              Ice season (fixed-wing                    Open-water season (helicopter only)
                                                                  aircraft only)         ---------------------------------------------------------------
                                                         --------------------------------
                        Activity                                             Forward-        Tulageak     East Simpson 1    West Dease      Snow trail
                                                          Winter support      looking       inspection    inspection and  inspection and  inspection and
                                                                             infrared       and cleanup       cleanup         cleanup         cleanup
--------------------------------------------------------------------------------------------------------------------------------------------------------
Altitude *..............................................            High             Low            High            High             Low             Low
Total Flights...........................................              24              12               7               2               2               4
Proportion of Season....................................         0.00444         0.01200         0.00041         0.00017         0.00002         0.00451
Proportion of Flight....................................          0.6688          0.1454           0.096          0.5541               1           0.077
 in Coastal Zone........................................
Proportion of Flight....................................          0.3312          0.8546           0.904          0.4459               0           0.923
 in Inland Zone.........................................
Total Encounter Rate....................................          0.0347          0.0107          0.1466          0.8223          1.4800          0.1186
 (bears/km\2\/season) **................................
Harassment Rate.........................................           0.001            0.56           0.002           0.002            0.97            0.97
Total Takeoffs and Landings.............................              24               0              14               4               4              24
Landing Time/Season.....................................          0.0007               0          0.0008          0.0002          0.0002          0.0014
Takeoff Time/Season.....................................          0.0007               0          0.0008          0.0002          0.0002          0.0014
Landing and Takeoff Harassment Rate.....................            0.89            0.89            0.99            0.99            0.99            0.99
Number of Level B Harassment of Activity................          0.0012          0.0006          0.0490          0.0140          0.0142          0.0883
Total number of Level B harassment across all aircraft activities                                 0.1673  ..............
--------------------------------------------------------------------------------------------------------------------------------------------------------
* High-altitude flight is defined as between 457 m (1,500 ft) and 610 m (2,000 ft) altitude. Low altitude is defined as between 122 m (400 ft) and 305 m
  (1,000 ft) altitude. There are no mid-altitude flights considered for this project.
** Accounts for unequal encounter rates over coastal and inland zones.

Analysis Approach for Estimating Harassment During Aerial Infrared 
(AIR) Surveys

    Typically, entities operating on the North Slope conduct polar bear 
den surveys using AIR during every denning season. Although the purpose 
for these surveys is to detect polar bear dens to mitigate impacts, 
polar bears on the surface can be harassed by the overflights. These 
surveys are not conducted along specific flight paths and generally 
overlap previously surveyed areas within the same flight. Therefore, we 
used different methodology to estimate harassment of surface polar 
bears during AIR surveys.
    We estimated the period of AIR surveys to last 12 days with a 
maximum of 6 hours of flight time per day, resulting in a maximum total 
of 72 flight-hours per year. To determine the number of hours AIR 
flights are likely to survey coastal and inland zones, we identified 
the area where project activities and denning habitat overlap and 
buffered this area by 1.6 km (1 mi). We then divided the buffered 
denning habitat by zone and determined the proportion of coastal and 
inland denning habitat. Using this proportion, we estimated the number 
of flight hours spent within each zone and determined

[[Page 88952]]

the proportion of the ice season in which AIR surveys impacted each 
zone (see Estimating Area of Impact for Aircraft Activities). We then 
estimated the aircraft's impact area for takeoffs, survey altitude, and 
landings. The area impacted by AIR surveys was multiplied by the 
seasonal encounter rates of polar bears for the appropriate zones and 
the proportion of the ice season in which AIR flights were flown to 
determine the number of polar bears encountered. We then multiplied the 
number of polar bears encountered per zone by the altitude harassment 
rate to determine the number of polar bears harassed during AIR 
surveys.

Estimated Harassment from Aircraft Activities

    Using the approaches described above, we estimated the total number 
of polar bears expected to be harassed by the aircraft activities 
during the proposed IHA period. Total number of expected Level B 
harassment events for this proposed IHA by aircraft activities, 
including AIR surveys, is 0.1673 bears, rounded up to one bear.

Denning Analysis

    Below we provide a complete description and results of the polar 
bear den simulation model used to assess impacts to denning polar bears 
from disturbance associated with all phases of the specified 
activities. We updated the analysis used to estimate impacts on denning 
polar bears from the 2021-2026 Beaufort Sea ITR (86 FR 42982, August 5, 
2021) to include information on anticipated survival rates for recently 
emerged polar bear cubs.

Den Simulation

    We simulated dens across the entire North Slope of Alaska, ranging 
from the areas identified as denning habitat (Durner et al. 2006, 2013; 
Durner and Atwood 2018) contained within the National Petroleum 
Reserve-Alaska (NPRA) in the west to the Canadian border in the east. 
To simulate dens on the landscape, we relied on the estimated number of 
dens in three different regions of northern Alaska provided by Atwood 
et al. (2020). These included the NPRA, the area between the Colville 
and Canning rivers (CC), and the Arctic National Wildlife Refuge (NWR). 
The mean estimated number of dens in each region during a given winter 
were as follows: 12 dens (95 percent confidence interval [CI]: 3-26) in 
the NPRA, 25 dens (11-47) in the CC region, and 14 dens (5-30) in the 
Arctic NWR (Patil et al. 2022). For each iteration of the model 
(described below), we drew a random sample from a gamma distribution 
for each of the regions based on the above parameter estimates, which 
allowed uncertainty in the number of dens in each area to be 
perpetuated through the modeling process. Specifically, we used the 
method of moments (Hobbs and Hooten 2015) to develop the shape and rate 
parameters for the gamma distributions as follows: NPRA (12\2\/
5.8\2\,12/5.8\2\), CC (25\2\/9.5\2\,25/9.5\2\), and Arctic NWR (14\2\/
6.3\2\,14/6.3\2\).
    Because not all areas in northern Alaska are equally used for 
denning and some areas do not contain the requisite topographic 
attributes required for sufficient snow accumulation for den 
excavation, we did not simply randomly place dens on the landscape. 
Instead, we followed a similar approach to that used by Wilson and 
Durner (2020) with some additional modifications to account for the 
differences in denning ecology in the CC region related to a preference 
to den on barrier islands and a general (but not complete) avoidance of 
actively used industrial infrastructure. Using the USGS polar bear den 
catalogue (Durner et al. 2020), we identified polar bear dens that 
occurred on land in the CC region and that were identified either by 
Global Positioning System (GPS)-collared polar bears or through 
systematic surveys for denning polar bears (Durner et al. 2020). This 
process resulted in a sample of 37 dens of which 22 (i.e., 60 percent) 
occurred on barrier islands. For each iteration of the model, we then 
determined how many of the estimated dens in the CC region occurred on 
barrier islands versus the mainland.
    To make this determination, we first took a random sample from a 
binomial distribution to determine the expected number of dens from the 
den catalogue (Durner et al. 2020) that should occur on barrier islands 
in the CC region during that given model iteration; 
nbarrier~Binomial(37, 22/37), where 37 represents the total 
number of dens in the den catalogue (Durner et al. 2020) in the CC 
region suitable for use (as described above) and 22/37 represents the 
observed proportion of dens in the CC region that occurred on barrier 
islands. We then divided nbarrier by the total number of 
dens in the CC region suitable for use (i.e., 37) to determine the 
proportion of dens in the CC region that should occur on barrier 
islands (i.e., pbarrier). We then multiplied 
pbarrier with the simulated number of dens in the CC region 
(rounded to the nearest whole number) to determine how many dens were 
simulated to occur on barrier islands in the region.
    In NPRA, the den catalogue (Durner et al. 2020) data indicated that 
two dens occurred outside of defined denning habitat (Durner et al. 
2013), so we took a similar approach as with the barrier islands to 
estimate how many dens occur in areas of NPRA with the den habitat 
layer during each iteration of the model; 
nhabitat~Binomial(15, 13/15), where 15 represents the total 
number of dens in NPRA from the den catalogue (Durner et al. 2020) 
suitable for use (as described above), and 13/15 represents the 
observed proportion of dens in NPRA that occurred in the region with 
den habitat coverage (Durner et al. 2013). We then divided 
nhabitat by the total number of dens in NPRA from the den 
catalogue (i.e., 15) to determine the proportion of dens in the NPRA 
region that occurred in the region of the den habitat layer 
(phabitat). We then multiplied phabitat with the 
simulated number of dens in NPRA (rounded to the nearest whole number) 
to determine the number of dens in NPRA that occurred in the region 
with the den habitat layer. Because no infrastructure exists and no 
activities are proposed to occur in the area of NPRA without the den 
habitat layer, we considered the potential impacts of activity only to 
those dens simulated to occur in the region with denning habitat 
identified (Durner et al. 2013).
    To account for the potential influence of BLM's activities on the 
distribution of polar bear selection of den sites, we again relied on 
the subset of dens from the den catalogue (Durner et al. 2020) 
discussed above. We further restricted the dens to only those occurring 
on the mainland because no permanent infrastructure occurred on barrier 
islands with identified denning habitat. We then determined the minimum 
distance to permanent infrastructure that was present during the year 
when the den was identified. The proportion of empirical dens <=5 km 
(3.1 mi) from infrastructure was 0.25. Thus, for the mainland portion 
of simulated dens in the CC region, we determined how many should be 
simulated to occur <=5 km from infrastructure, and how many should be 
simulated to occur >5 km from infrastructure at each iteration of the 
model. The number of mainland dens <=5 km from infrastructure was 
modeled as n<=5km~ Binomial(nCC_mainland,0.25) 
where nCC_mainland is the number of dens simulated to occur 
on the mainland portion of the CC region during one iteration of the 
model. The number of dens >5 km from infrastructure in the mainland 
portion of the CC region was calculated as: n>5km= 
nCC_mainland-n<=5km
    To determine the distribution of dens, we used a scaled adaptive 
kernel

[[Page 88953]]

density estimator applied to observed den locations, which took the 
form
[GRAPHIC] [TIFF OMITTED] TN26DE23.002

where the adaptive bandwidth for the location of the ith den and each 
location in the study area. The indicator functions allowed the 
bandwidth to vary abruptly between the mainland and barrier islands. 
The parameters were chosen so that the density estimate approximated 
the observed density of dens and our understanding of likely den 
locations in areas with low sampling effort.
    To simulate dens on the landscape, we first assigned each section 
of potential den habitat with a relative probability of use by polar 
bears based on the utilization distribution described above. We then 
randomly assigned dens to a section of potential denning habitat with a 
multinomial distribution based on the assigned relative probabilities 
for each section of potential denning habitat. For dens being simulated 
on the mainland in the CC region, an additional step was required. We 
first assigned a simulated den whether it should occur near 
infrastructure (i.e., <=5 km) or away (i.e., >5 km) from 
infrastructure. We subset the kernel density grid cells that occurred 
<=5 km from infrastructure and those that occurred >5 km. We then 
selected a section of potential denning habitat to simulate the den 
from the appropriate kernel density subset (i.e., near/far from 
infrastructure) based on their underlying probabilities using a 
multinomial distribution.
    For each simulated den, we assigned dates of key denning events; 
den entrance, birth of cubs, when cubs reached 60 days of age, den 
emergence, and departure from the den site after emergence. These 
represent the chronology of each den under undisturbed conditions.
    We selected the entrance date for each den from a normal 
distribution parameterized by entrance dates of radio-collared polar 
bears in the SBS stock that denned on land included in Rode et al. 
(2018) and published in USGS (2018; n=52, mean=November 11, standard 
deviation [SD]=18 days); we truncated this distribution to ensure that 
all simulated dates occurred within the range of observed values (i.e., 
September 12 to December 22).
    We selected a date of birth for each litter from a normal 
distribution with a mean birth date of December 15 and an SD of 10 
days. We then restricted random samples of birth dates to occur between 
December 1 and January 15, which is believed to be when most cubs are 
born (Messier et al. 1994, Van de Velde et al. 2003).
    We selected the emergence date as a random draw from an asymmetric 
Laplace distribution with parameters [mu]=81.0, [sigma]=4.79, and 
p=0.79 estimated from the empirical emergence dates in Rode et al. 
(2018) and published in USGS (2018, n=52) of radio-collared polar bears 
in the SBS subpopulation that denned on land using the mleALD function 
from package `ald' (Galarzar and Lachos 2018) in program R (R Core 
Development Team). We constrained simulated emergence dates to occur 
within the range of observed emergence dates (January 9 to April 9) and 
not to occur prior to cubs reaching an age of 60 days.
    Finally, we assigned the number of days each family group spent at 
the den site post-emergence based on values reported in three 
behavioral studies, Smith et al. (2007, 2010, 2013), and Robinson 
(2014), which monitored dens near the target area immediately after 
emergence (n=25 dens). Specifically, we used the mean (8.0) and SD 
(5.5) of the dens monitored in these studies to parameterize a gamma 
distribution using the method of moments (Hobbs and Hooten 2015) with a 
shape parameter equal to 8.0\2\/5.5\2\ and a rate parameter equal to 
8.0/5.5\2\; we selected a post-emergence, pre-departure time for each 
den from this distribution.
    Additionally, we assigned each den a litter size by drawing the 
number of cubs from a multinomial distribution with probabilities 
derived from litter sizes (n=25 litters) reported in Smith et al. 
(2007, 2010, 2013) and Robinson (2014). Because there is some 
probability that a female naturally emerges with 0 cubs, we also wanted 
to ensure this scenario was captured. However, it is difficult to 
parameterize the probability of litter size equal to 0 because it is 
rarely observed.
    Therefore, we assumed that dens with denning durations less than 79 
days, which is the shortest den duration in which a female was later 
observed with cubs, had a litter size equal to 0. Only 3 polar bears in 
the USGS (2018) data met these criteria, leading to an assumed 
probability of a litter size of 0 at emergence being 0.07. We therefore 
assigned the probability of 0, 1, 2, or 3 cubs as 0.07, 0.15, 0.71, and 
0.07, respectively.

Impact Area of Specified Activities

    The model developed by Wilson and Durner (2020) provides a template 
for estimating the level of potential impact on denning polar bears 
during the specified activities while also considering the natural 
denning ecology of polar bears in the region. The approach developed by 
Wilson and Durner (2020) also allows for the incorporation of 
uncertainty in both the metric associated with denning polar bears and 
in the timing and spatial patterns of the specified activities when 
precise information on those activities is unavailable. We assumed any 
dens within 1.6 km (1 mi) from project activities were exposed to 
disturbance.

AIR Surveys

    We assumed that all exploration and transit areas would have two 
AIR surveys flown each winter. The first survey would occur between 
December 1 and December 25, 2023, and the second survey between 
December 15, 2023, and January 10, 2024, with a minimum of 24 hours 
between surveys. During each iteration of the model, each AIR survey 
was randomly assigned a probability of detecting dens. Whereas previous 
analyses have used the results of Wilson and Durner (2020) to inform 
this detection probability, two additional studies (Smith et al. 2020, 
Woodruff et al. 2022b) have been conducted since Wilson and Durner 
(2020) was published. Woodruff et al. (2022b) considered the 
probability of detecting heat signatures from artificial polar bear 
dens. They did not find a relationship between den snow depth and 
detection and estimated a mean detection rate of 0.24. A recent study 
by Smith et al. (2020) estimated that the detection rate for actual 
polar bear dens in northern Alaska was 0.45 and also did not report any 
relationship between detection and den snow depth. Because the study by 
Wilson and Durner (2020) reported detection probability only for dens 
with less than 100 cm (39.4 in) snow depth, we needed to correct it to 
also include those dens with greater than 100 cm (39.4 in) snow depth. 
Based on the distribution of snow depths used by Wilson and Durner 
(2020) derived from data in Durner et al. (2003), we determined that 24 
percent of dens have snow depths greater than 100 cm. After taking 
these into account, the overall detection probability from Wilson and 
Durner (2020) including dens with snow depths greater than 100 cm was 
estimated to be 0.54. This led to a mean detection of 0.41 and a SD of 
0.15 across the three studies. We used these values, and the method of 
moments (Hobbs and Hooten 2015), to inform a Beta distribution:

[[Page 88954]]

[GRAPHIC] [TIFF OMITTED] TN26DE23.003

from which we drew a detection probability (p) for each of the 
simulated AIR surveys during each iteration of the model.

Model Implementation

    For each iteration of the model, we first determined which dens 
were exposed to the specified activities. We assumed that any den 
within 1.6 km (1 mi) of human activities was exposed (MacGillivray et 
al. 2003, Larson et al. 2020), excluding those detected during an AIR 
survey (but only if activity did not occur prior to AIR surveys). We 
then identified the stage in the denning period when the exposure 
occurred based on the date range of the activities the den was exposed 
to: den establishment (i.e., initial entrance into den until cubs are 
born), early denning (i.e., birth of cubs until they are 60 days old), 
late denning (i.e., date cubs are 60 days old until den emergence) and 
post-emergence (i.e., the date of den emergence until permanent 
departure from the den site). We then determined whether the exposure 
elicited a response by the denning polar bear based on probabilities 
derived from the reviewed case studies (Woodruff et al. 2022a).
    Specifically, we divided the number of cases that documented 
responses associated with either a Level B harassment (i.e., potential 
to cause a disruption of behavioral patterns), Level A harassment 
(i.e., potential to injure an animal), or lethal take (i.e., cub 
abandonment) of polar bears by the total number of cases with that 
combination of period and exposure type (table 6). Level B harassment 
was applicable to both adults and cubs, if present, whereas Level A 
harassment and lethal take were applicable to only cubs. AIR surveys 
were considered to be a source of potential impact because these 
surveys are conducted with fixed-wing aircraft that fly at altitudes 
below 457 m (1,500 ft). Level B harassment as a result of AIR surveys 
was applicable to only adults and only during the den establishment 
period because this period is the only denning period when AIR surveys 
have been observed to cause disturbance to denning polar bears (Amstrup 
1993, Woodruff et al. 2022b). In thousands of hours of AIR surveys 
conducted in northern Alaska over the last decade, we are not aware of 
a single instance of a polar bear abandoning its den during the early 
denning period due to an AIR survey overflight. These responses would 
be readily observable on the thermal cameras, and the fact that none 
have been observed indicates that den abandonment very likely does not 
occur given the brief duration of the aircraft overflight and the 
distance and altitude of the aircraft from the den site.
    For dens exposed to activity, we used a multinomial distribution 
with the probabilities of different levels of take for that period 
(table 6) to determine whether a den was disturbed or not. If a lethal 
take was simulated to occur, a den was not allowed to be disturbed 
again during the subsequent denning periods because the outcome of that 
denning event was already determined.
    The level of impact associated with a disturbance varied according 
to the severity and timing of the exposure (table 6). Exposures that 
resulted in emergence from dens prior to cubs reaching 60 days of age 
were considered lethal takes of cubs. If an exposure resulted in a 
Level A harassment during the late denning period, we first assigned 
that den a new random emergence date from a uniform distribution that 
ranged between the first date of exposure during the late denning 
period and the original den emergence date. We then determined whether 
that den was disturbed during the post-emergence period, but the 
probability of disturbance was dependent on whether a den was disturbed 
(i.e., Level A harassment) during the late denning period or not (table 
6). If an exposure resulted in a Level A harassment during the post-
emergence period, we assigned the den a new time spent at the den site 
post-emergence from a uniform distribution that ranged from 0 to the 
original simulated time at the den post-emergence.
    Recent research suggests that litter survival is related to the 
date of den emergence and time spent at the den post-emergence 
(Andersen et al. in review), with litters having higher survival the 
later they emerge in the spring and the longer they spend at the den 
site after emergence. To determine if dens disturbed during the late 
denning and/or post-emergence period(s) experienced serious Level A 
harassment, we relied on estimates of litter survival until 
approximately 100 days post emergence derived from the analysis of 
empirical data on the dates of emergence from the den and departure 
from the den site (Anderson et al. in review). These estimates are 
dependent on the date of emergence and time spent at the den site post-
emergence. For each den disturbed during the late denning and/or post-
emergence periods, we obtained a random sample of regression 
coefficients from the posterior distribution and calculated the 
probability of a litter surviving approximately 100 days post-emergence 
with the following equation:

logit(s) = [beta]0 + [beta]1emerge + 
[beta]2depart

where s is the probability of at least one cub being alive 
approximately 100 days post-emergence, [beta]0 is the 
intercept coefficient, [beta]1 is the coefficient associated 
with the Julian date of emergence (emerge), and [beta]2 is 
the coefficient associated with the number of days the family group 
stayed at the den site post-emergence before departing (depart). If s 
was calculated to be <0.50, then the cubs in that simulated litter were 
assigned a take by serious Level A harassment, otherwise they were 
assigned a take by non-serious Level A harassment. These probabilities 
are based on estimates of litter survival derived from the analysis of 
empirical data on the dates of emergence from the den and departure 
from the den site (Anderson et al. in review).
    We developed the code to run this model in program R (R Core 
Development Team 2020) and ran 10,000 iterations of the model (i.e., 
Monte Carlo simulation) to derive the estimated number of dens 
disturbed and associated levels of harassment. We then determined the 
number of cubs that would have lethal take, serious Level A harassment, 
non-serious Level A harassment, and Level B harassment, and the number 
of females that would experience Level B harassment. Table 6 shows the 
probability of an exposure resulting in the types of harassment of 
denning polar bears.

[[Page 88955]]



  Table 6--Probability That an Exposure Elicited a Response by Denning Polar Bears That Would Result in Level B
                            Harassment, Level A Harassment, Lethal Take, and No Take
----------------------------------------------------------------------------------------------------------------
                     Period                           Level B         Level A         Lethal          No take
----------------------------------------------------------------------------------------------------------------
Den Establishment...............................           0.380              NA              NA           0.620
Early Denning...................................              NA              NA           0.180           0.820
Late Denning....................................           0.000         * 0.490           0.000           0.510
Post-emergence-Undisturbed......................           0.220         * 0.780           0.000           0.000
Post-emergence-Disturbed........................           0.429         * 0.571           0.000           0.000
----------------------------------------------------------------------------------------------------------------
Level B harassment was applicable to both adults and cubs, if present; Level A harassment and lethal take were
  applicable to cubs only and were not possible during the den establishment period, which ended with the birth
  of the cubs. Probabilities were calculated from the analysis of 56 case studies of polar bear responses to
  human activity. During the early denning period, there was no Level A harassment for cubs, only lethal take.
  Level A harassment is considered ``serious'' when the disturbed emergence and/or time at den site post
  emergence led to an estimate of litter survival <0.50. We provide two sets of take probabilities for the post-
  emergence period. The first (Post-emergence-Undisturbed) is the set of probabilities when a den has not been
  disturbed during the late denning period. The second (Post-emergence-Disturbed) is the set of probabilities
  for a den that was disturbed during the late denning period (Rode et al. 2018, Andersen et al. in review).
* The assignment of serious and non-serious Level A harassment is a function of when a simulated disturbance
  occurred in comparison to the anticipated emergence date and/or den departure date.

Model Results

    On average, we estimated 3.18 (median=3; 95 percent CI: 0-8) land-
based dens in the area that were potentially exposed to disturbance 
from the specified activities during the proposed IHA period. Estimates 
for different levels of take are presented in table 7. We also 
estimated that take by Level B harassment from AIR surveys was never 
greater than a mean of 0.43 (median=0; 95 percent CI: 0-2). The 
distributions of both non-serious Level A harassment, serious Level A 
harassment, and lethal take were non-normal and heavily skewed, as 
indicated by markedly different mean and median values. The heavily 
skewed nature of these distributions has led to a mean value that is 
not representative of the most common model result.
    The median number, which is the midpoint value of a frequency 
distribution of all model results, for serious Level A harassment is 0 
and the median number for lethal take is 0, indicating the most common 
model result is 0 for both serious Level A harassment and lethal take 
over the 1-year IHA period. The probability of greater than or equal to 
1 serious Level A harassment is 0.15, and the probability of greater 
than or equal to 1 lethal take is 0.33.
    In considering whether a polar bear's mortality may result from the 
specified activities, we use the combined probability that a greater 
than or equal to 1 serious Level A harassment or lethal take will occur 
because both types of take are likely to result in a polar bear's 
mortality. The combined probability that a greater than or equal to 1 
serious Level A harassment or lethal take occur within a simulation 
iteration will be less than or equal to the sum of probabilities for 
each of those types of takes considered separately. This is because 
iterations where both types of take occur will be counted only once 
when considering the combined probability, not once for each type of 
take. Due to the low probability (0.42) of greater than or equal to 1 
serious Level A harassment/lethal take that could occur within the 
proposed IHA period, combined with the median of 0, we do not 
anticipate the specified activities will result in either serious Level 
A harassment or lethal take of polar bears during the proposed IHA 
period. The median number of non-serious Level A harassment was 2. The 
probability of greater than or equal to 1 take by non-serious Level A 
harassment is over a 50 percent chance (0.67), indicating that less 
than half of the models resulted in 0 takes by non-serious Level A 
harassment.

                   Table 7--Results of the Den Disturbance Model for the Specified Activities
----------------------------------------------------------------------------------------------------------------
                  Type of take                     Probability        Mean           Median       95 percent CI
----------------------------------------------------------------------------------------------------------------
Level B Harassment.............................            0.90            3.60               3             0-11
Non-Serious Level-A Harassment.................            0.67            2.26               2              0-8
Serious Level-A Harassment.....................            0.15            0.34               0              0-3
Lethal.........................................            0.33            0.79               0              0-4
----------------------------------------------------------------------------------------------------------------
Estimates are provided for the probability, mean, median, and 95 percent confidence interval (CI) for Level B
  harassment, non-serious Level A harassment, serious Level A harassment, and lethal take. The probabilities
  represent the probability of >= 1 take of a polar bear during each denning season.

Critical Assumptions

    To conduct this analysis and estimate the potential amount of Level 
B and non-serious Level A harassment, several critical assumptions were 
made.
    Level B harassment is equated herein with behavioral responses that 
indicate harassment or disturbance but not to the extent that cause the 
animal to experience significant biological consequences. Our estimates 
do not account for variable responses by polar bear age and sex; 
however, sensitivity of denning polar bears was incorporated into the 
analysis. The available information suggests that polar bears are 
generally resilient to low levels of disturbance. Females with 
dependent young and juvenile polar bears are physiologically the most 
sensitive (Andersen and Aars 2008) and most likely to experience 
harassment from disturbance. Not enough information on composition of 
the SBS polar bear stock in the specified project area is available to 
incorporate individual variability based on age and sex or to predict 
its influence on harassment estimates. Our estimates are derived from a 
variety of sample populations with various age and sex structures, and 
we assume the exposed population will have a similar composition and, 
therefore, the response rates are applicable.
    The estimates of behavioral response presented here do not account 
for the individual movements of animals in response to the specified 
activities. Our assessment assumes animals remain stationary (i.e., 
density does not change). Not enough information is available about the 
movement of polar bears in response to specific disturbances to refine 
this assumption.
    SBS polar bears create maternal dens on the sea ice as well as on 
land. The

[[Page 88956]]

den simulation used in our analysis does not simulate dens on the sea 
ice. However, the specified activities will be conducted entirely on 
land and only a small percentage of the activities will occur within 
1.6 km (1 mi) of the coastline. Therefore, the impact of the activities 
will be primarily limited to land-based dens within 1.6 km (1 mi) of 
the project infrastructure, and this impact area will be surveyed 
during AIR surveys to mitigate impacts on denning polar bears.
    The specific segments of the snow roads depicted in figure 1 that 
will be used for mobilization, resupply, and demobilization are not 
currently known. For the purposes of the above analyses and estimates 
of take by non-serious Level A and Level B harassment, and the risks of 
lethal take or take by serious Level A harassment, we assumed that all 
routes might potentially be used at some point during the specified 
activities. This assumption results in an overestimate of the take that 
is likely to occur over the 1-year IHA period but accounts for all 
possible operational scenarios.

Sum of Harassment From All Sources

    A summary of total estimated take via Level B and non-serious Level 
A harassment during the projects by source is provided in table 8. The 
potential for serious Level A and lethal take was also explored. Lethal 
take or serious Level A harassment would not occur outside of denning 
polar bears because the level of sound and visual stimuli experienced 
by polar bears on the surface would not be significant enough to result 
in injury or death. Denning polar bears, however, may be subject to 
repeated exposures, significant energy expenditure from den abandonment 
or departure, and/or potential impacts to a cub if the den is abandoned 
or departed prematurely. The Service estimated a low probability (0.35) 
for greater than or equal to 1 serious Level A harassment/lethal take 
of a denning polar bear and a median of 0 takes of denning polar bears 
by serious Level A harassment and lethal take for the 1-year duration 
of the IHA period.

 Table 8--Total Estimated Takes by Harassment of Polar Bears and Source
------------------------------------------------------------------------
                                                             Number of
                                                             estimated
              Source and type of harassment                 harassment
                                                              events
------------------------------------------------------------------------
Bears on the surface-summer--Level B harassment.........               7
Bears on the surface-winter--Level B harassment.........               6
Aircraft activities-summer and winter--Level B                         1
 harassment.............................................
Denning bears--Level B harassment.......................               4
Denning bears--non-serious Level A harassment...........               3
                                                         ---------------
    Total...............................................              21
------------------------------------------------------------------------

Determinations and Findings

    In making these draft findings, we considered the best available 
scientific information, including: the biological and behavioral 
characteristics of the species, the most recent information on species 
distribution and abundance within the area of the specified activities, 
the current and expected future status of the stocks (including 
existing and foreseeable human and natural stressors), the potential 
sources of disturbance caused by the project, and the potential 
responses of marine mammals to this disturbance. In addition, we 
reviewed applicant-provided materials, information in our files and 
datasets, published reference materials, and consulted with species 
experts.

Small Numbers

    For our small numbers determination, we consider whether the 
estimated number of polar bears to be subjected to incidental take is 
respectively small relative to the population size of the species or 
stock.
    1. We estimate that BLM's proposed specified activities in the 
specified geographic region will cause the take of no more than 18 
polar bears by Level B harassment and no more than 3 polar bears by 
non-serious Level A harassment during the 1-year period of this 
proposed IHA (see table 8). Take of 21 animals is 2.32 percent of the 
best available estimate of the current SBS stock size of 907 animals 
(Bromaghin et al. 2015, Atwood et al. 2020) ((21/907)x100[ap]2.32 
percent) and represents a ``small number'' of polar bears of that 
stock.
    2. The footprint of the specified activities within the specified 
geographic region is small relative to the range of the SBS stock of 
polar bears. Polar bears from the SBS range well beyond the boundaries 
of the proposed IHA region. As such, the IHA region itself represents 
only a subset of the potential area in which the polar bear may occur. 
Thus, the Service concludes that a small portion of the SBS polar bear 
populations may be present in the specified geographic region during 
the time of the specified activities.

Small Numbers Conclusion

    We propose a finding that take of up to 21 SBS polar bears 
represents a small number of the SBS stock of polar bears.

Negligible Impact

    For our negligible impacts determination, we consider the 
following:
    1. The distribution and habitat use patterns of polar bears 
indicate that relatively few polar bears will occur in the specified 
areas of activity at any particular time and, therefore, few polar 
bears are likely to be affected.
    2. The documented impacts of previous activities similar to the 
specified activities on polar bears, taking into consideration the 
baseline of existing impacts from factors such as oil and gas 
activities in the area and other ongoing or proposed ITAs, suggests 
that the types of activities analyzed for this proposed IHA will have 
minimal effects limited to short-term, temporary behavioral changes. 
This is true not only for Level B harassment but also for the non-
serious Level A harassment. While non-serious Level A harassment has 
the potential to result in the injury of one or more cubs during the 
denning period, this type of harassment is not anticipated to result in 
long-term impacts that are likely to result in mortality. Therefore, we 
anticipate the specified activities will not have lasting impacts that 
could significantly affect an individual polar bear's health, 
reproduction, or survival. The limited extent of anticipated impacts on 
polar bears is unlikely to adversely affect annual rates of polar bear 
survival or recruitment.
    3. The IHA, if finalized, would require implementation of 
monitoring requirements and mitigation measures designed to reduce the 
potential impacts of their operations on polar bears. Den detection 
surveys for polar bears and adaptive mitigation and management 
responses based on real-time monitoring information (described in this 
proposed authorization) will be used to avoid or minimize interactions 
with polar bears and, therefore, limit potential disturbance of these 
animals.
    4. The Service does not anticipate any lethal take or serious Level 
A harassment that would remove individual polar bears from the 
population or prevent their successful reproduction. This proposed IHA 
does

[[Page 88957]]

not authorize serious injury take that will likely result in the death 
of a polar bear.
    We also consider the conjectural or speculative impacts associated 
with these specified activities. The specific congressional direction 
described below justifies balancing the probability of such impacts 
with their severity: If potential effects of a specified activity are 
conjectural or speculative, a finding of negligible impact may be 
appropriate. A finding of negligible impact may also be appropriate if 
the probability of occurrence is low, but the potential effects may be 
significant. In this case, the probability of occurrence of impacts 
must be balanced with the potential severity of harm to the species or 
stock when determining negligible impact. In applying this balancing 
test, the Service will thoroughly evaluate the risks involved and the 
potential impacts on marine mammal populations. Such determination will 
be made based on the best available scientific information (54 FR 
40338, September 29, 1989, quoting 53 FR 8474, March 15, 1988 and 132 
Cong. Rec. S 16305 (October 15, 1986)).
    The potential effects of most concern here are the serious injury 
or mortality of cubs that could result from disturbances during certain 
periods of the denning season. The Service estimated that the 
probability of greater than or equal to one lethal take or take by 
serious Level A harassment that is likely to result in the mortality of 
a denning polar bear is 0.32, combined with a median of 0 takes, within 
the 1-year period of this proposed IHA. Therefore, the Service does not 
anticipate any lethal take or serious Level A harassment will occur 
during the IHA period. If a den is disturbed and lethal take or take by 
serious Level A harassment were to occur, this take would be limited to 
only cubs during the denning period. Denning females are limited to 
take by Level B harassment. Therefore, the number of potentially 
available reproductive females that would contribute to recruitment for 
the SBS stock would remain unaffected if a den disturbance were to 
result in the mortality of the cubs. The loss of a cub or litter would 
reduce the annual recruitment rate for the SBS stock of polar bears.
    The SBS stock of polar bears is currently estimated as 907 polar 
bears (Bromaghin et al. 2015, 2021; Atwood 2020). The loss of one 
litter ranges from 0 percent (0 cubs) to approximately 0.33 percent (3 
cubs) of the annual SBS stock size of polar bears (((0 cubs to 3 cubs)/
907)x100[ap]0 to 0.33). Cub litter survival was estimated at 50 percent 
(90 percent CI: 33-67 percent) for the SBS stock during 2001-2006 
(Regehr et al. 2010). A female may lose her litter for several reasons 
separate from den disturbance. The determining factor for polar bear 
stock growth is adult female survival (Eberhardt 1990). Consequently, 
the loss of female cubs has a greater impact on annual recruitment 
rates for the SBS stock of polar bears compared to male cubs. If a den 
disturbance were to result in the mortality of the entire litter, the 
female would be available to breed during the next mating season and 
could produce another litter during the next denning season.
    Based on the relatively low potential for cub mortality associated 
with these specified activities, and the recognition that even if a den 
is disturbed, the number of potentially affected cubs would be minimal 
and the number of reproductive females in the stock would remain the 
same, the Service does not anticipate that the conjectural or 
speculative impacts associated with these specified activities warrant 
a finding of non-negligible impact or otherwise preclude issuance of 
this proposed IHA. We reviewed the effects of the specified well-
plugging and reclamation activities on polar bears, including impacts 
from surface interactions, aircraft overflights, and den disturbance. 
Based on our review of these potential impacts, past monitoring 
reports, and the biology and natural history of polar bears, we 
anticipate that such effects will be limited to short-term behavioral 
disturbances.
    We have evaluated climate change regarding polar bears as part of 
the environmental baseline. Climate change is a global phenomenon and 
was considered as the overall driver of effects that could alter polar 
bear habitat and behavior. The Service is currently involved in 
research to understand how climate change may affect polar bears. As we 
gain a better understanding of climate change effects, we will 
incorporate the information in future authorizations.
    We find that the impacts of these specified activities cannot be 
reasonably expected to, and are not reasonably likely to, adversely 
affect SBS polar bears through effects on annual rates of recruitment 
or survival. We therefore find that the total take estimated above and 
proposed for authorization will have a negligible impact on SBS polar 
bears. We do not propose to authorize lethal take or take by serious 
Level A harassment, and we do not anticipate that any lethal take or 
take by serious Level A harassment will occur.

Impact on Subsistence Use

    Based on past community consultations, locations of hunting areas, 
no anticipated overlap of hunting areas and project activities, and the 
best scientific information available, including monitoring data from 
similar activities, we propose a finding that take caused by the oil 
well plugging and reclamation, soil sampling, snow trail, pad, and 
airstrip construction, and summer cleanup activities in the project 
area will not have an unmitigable adverse impact on the availability of 
polar bears for taking for subsistence uses during the proposed 
timeframe.
    While polar bears represent a small portion, in terms of the number 
of animals, of the total subsistence harvest for the Utqiagvik, 
Nuiqsut, Wainwright and Atqasuk communities, their harvest is important 
to Alaska Natives. BLM will be required to notify the cities of 
Wainwright and Utqiagvik and the Native Villages of Atqasuk and Nuiqsut 
of the planned activities and document any discussions of potential 
conflict. BLM must make reasonable efforts to ensure that activities do 
not interfere with subsistence hunting and that adverse effects on the 
availability of polar bears are minimized. Should such a concern be 
voiced, development of plans of cooperation (POC), which must identify 
measures to minimize any adverse effects, will be required. The POC 
will ensure that project activities will not have an unmitigable 
adverse impact on the availability of the species or stock for 
subsistence uses. This POC must provide the procedures addressing how 
BLM will work with the affected Alaska Native communities and what 
actions will be taken to avoid interference with subsistence hunting of 
polar bears, as warranted.
    The Service has not received any reports and is not aware of 
information that indicates that polar bears are being or will be 
deterred from hunting areas or impacted in any way that diminishes 
their availability for subsistence use by oil well plugging and 
reclamation, soil sampling, snow trail, pad, and airstrip construction, 
and summer cleanup. If there is evidence that these activities are 
affecting the availability of polar bears for take for subsistence 
uses, we will reevaluate our findings regarding permissible limits of 
take and the measures required to ensure continued subsistence hunting 
opportunities.

Least Practicable Adverse Impact

    We evaluated the practicability and effectiveness of mitigation 
measures based on the nature, scope, and timing of the specified 
activities, the best

[[Page 88958]]

available scientific information, and monitoring data during BLM's 
activities in the specified geographic region. We propose a finding 
that the mitigation measures included within BLM's Request will ensure 
least practicable adverse impacts on polar bears (BLM 2023)
    Polar bear den surveys at the beginning of the winter season, the 
resulting 1.6-km (1-mi) operational exclusion zone around any known 
polar bear dens, and restrictions on the timing and types of activities 
in the vicinity of dens will ensure that impacts to denning female 
polar bears and their cubs are minimized during this critical period. 
Minimum flight elevations over polar bear areas and flight restrictions 
around observed polar bears and known polar bear dens will reduce the 
potential for aircraft disturbing polar bears. Finally, BLM will 
implement mitigation measures to prevent the presence and impact of 
attractants in camps such as the use of wildlife-resistant waste 
receptacles, daily food waste incineration, and storing hazardous 
materials in drums or other secure containers. These measures are 
outlined in a polar bear interaction plan that was developed in 
coordination with the Service and is part of BLM's application for this 
IHA. Based on the information we currently have regarding den and 
aircraft disturbance and polar bear attractants, we concluded that the 
mitigation measures outlined in BLM's Request (BLM 2023) and 
incorporated into this authorization will minimize impacts from the 
specified oil well plugging and reclamation, soil sampling, snow trail, 
pad, and airstrip construction, and summer cleanup activities to the 
extent practicable.
    Several mitigation measures were considered but determined to be 
not practicable. These measures are listed below:
     Grounding all flights if they must fly below 457 m (1,500 
ft)--Requiring all aircraft to maintain an altitude of 457 m (1,500 ft) 
at all times is not practicable as some operations may require flying 
below 457 m (1,500 ft) to perform necessary inspections or maintain 
safety of flight crew. Aircraft are required to fly above 457 m (1,500 
ft) at all times within 805 m (0.5 mi) of an observed polar bear unless 
there is an emergency.
     One-mile buffer around all known polar bear denning 
habitat--One-mile (1.6-km) buffer around all known polar bear denning 
habitat is not practicable as much of BLM's proposed project area 
occurs within 1.6 km (1 mi) of denning habitat; thus, to exclude all 
areas within 1.6 km of denning habitat would preclude the planned 
activities from occurring.
     Prohibition of driving over high relief areas, 
embankments, or stream and river crossings--While the denning habitat, 
such as high relief areas, embankments, and streams or river banks, 
must be considered during tundra travel, complete prohibition is not 
practicable. High relief areas, embankments, streams, and rivers occur 
throughout the project area. To completely avoid these types of areas 
would likely cause personnel to drive further away from established 
operational areas and unnecessarily create additional safety concerns. 
Furthermore, other mitigation measures to minimize impact to denning 
habitats are included and will minimize the risk imposed by driving 
over high relief areas, embankments, or stream and river crossings
     Use of a broader definition of ``denning habitat'' for 
operational offsets--There is no available data to support broadening 
the defining features of denning habitat beyond that established by 
USGS. Such a redefinition would cause an increase in the area surveyed 
for maternal dens, and the associated increase in potential harassment 
of polar bears on the surface would outweigh the mitigative benefits.
     Establishment of corridors for sow and cub transit to the 
sea ice--As there is no data to support the existence of natural 
transit corridors to the sea ice, establishment of corridors in the IHA 
area would be highly speculative. Therefore, there would be no 
mitigative benefit realized by their establishment.
     Require all activities to cease if a polar bear is injured 
or killed until an investigation is completed--The Service has 
incorporated reporting requirements into this proposed authorization 
for all polar bear interactions. While it may aid in any subsequent 
investigation, ceasing all activities may not be practicable or safe 
and, thus, will not be mandated.
     Require use of den detection dogs--It is not practicable 
or safe to require scent-trained dogs to detect dens due to the large 
spatial extent that would need to be surveyed within activity areas.
     Require the use of handheld or vehicle-mounted Forward 
Looking Infrared (FLIR)--The efficacy rates for AIR have been found to 
be four times more likely to detect dens versus ground-based FLIR 
(handheld or vehicle-mounted FLIR) due to impacts of blowing snow on 
detection. BLM has incorporated into their mitigation measures the use 
of handheld or vehicle-mounted FLIR when transiting rivers occurring in 
suitable denning habitat, but it is not practicable to use the 
equipment during all transit.
     Construct safety gates, fences, and enclosures to prevent 
polar bears from accessing facilities--This project will require no 
permanent facility/structures and encompasses a large area. 
Construction and deconstruction of barriers for a moving camp would 
increase potential human- polar bear interactions and impacts to polar 
bear habitat.
     Employ protected species observers (PSOs) for monitoring, 
recording, reporting, and implementing mitigation measures--All 
personnel will be trained in wildlife observation, employment of PSOs 
would not be anticipated to reduce impacts to polar bears. Monitoring, 
recording, reporting are described in the IHA application.
     Avoid areas of high-density polar bear use (e.g., barrier 
islands and coastline) including the establishment of camps and pads--
This measure is not practicable because the legacy wells that this 
project is focused on are all located along the coastline, and snow 
trail must also cross through these areas to reach the well sites.
     Avoid predominantly coastal routes for flight pathways--
This measure is not practicable because the remediation sites are 
located along the coast, and aviation access routes to project sites 
must occur over the coast.
     Restrict activity and travel over polar bear denning 
habitat to eliminate or lessen risk of den collapse--This project has 
activities that will travel over potential polar bear denning habitat. 
BLM has committed to multiple effective mitigation measures to minimize 
their potential impacts to polar bear denning habitat and reduce to 
chance of den collapse. Therefore, we believe that the probability of 
this project's activities causing a den collapse is near zero and 
additional mitigation measures would not further reduce the 
probability.

Required Determinations

National Environmental Policy Act (NEPA)

    We have prepared a draft environmental assessment in accordance 
with the NEPA (42 U.S.C. 4321 et seq.). We have preliminarily concluded 
that authorizing the nonlethal, incidental, unintentional take of 18 
SBS polar bears by Level B harassment and 3 SBS polar bears by non-
serious Level A harassment during the proposed harassment authorization 
period would not significantly affect the quality of the human 
environment and, thus, preparation of an environmental

[[Page 88959]]

impact statement for this incidental harassment authorization is not 
required by section 102(2) of NEPA or its implementing regulations. We 
are accepting comments on the draft environmental assessment as 
specified above in DATES and ADDRESSES.

Endangered Species Act

    Under the Endangered Species Act (ESA) (16 U.S.C. 1536(a)(2)), all 
Federal agencies are required to ensure the actions they authorize are 
not likely to jeopardize the continued existence of any threatened or 
endangered species or result in destruction or adverse modification of 
critical habitat. Prior to issuance of a final IHA, the Service will 
complete intra-Service consultation under section 7 of the ESA on our 
proposed issuance of an IHA. These evaluations and findings will be 
made available on the Service's website at https://ecos.fws.gov/ecp/report/biological-opinion.

Government-to-Government Consultation

    It is our responsibility to communicate and work directly on a 
Government-to-Government basis with federally recognized Alaska Native 
Tribes in developing programs for healthy ecosystems. We seek their 
full and meaningful participation in evaluating and addressing 
conservation concerns for protected species. It is our goal to remain 
sensitive to Alaska Native culture, and to make information available 
to Alaska Tribal organizations and communities. Our efforts are guided 
by the following policies and directives:
    (1) The Native American Policy of the Service (January 20, 2016);
    (2) The Alaska Native Relations Policy (currently in draft form; 
see 87 FR 66255, November 3, 2022);
    (3) Executive Order 13175 (January 9, 2000);
    (4) Department of the Interior Secretarial Orders 3206 (June 5, 
1997), 3225 (January 19, 2001), 3317 (December 1, 2011), 3342 (October 
21, 2016), and 3403 (November 15, 2021) as well as Director's Order 227 
(September 8, 2022);
    (5) The Alaska Government-to-Government Policy (a departmental 
memorandum issued January 18, 2001); and
    (6) the Department of the Interior's policies on consultation with 
Alaska Native Tribes and organizations.
    We have evaluated possible effects of the proposed IHA on federally 
recognized Alaska Native Tribes and ANCSA (Alaska Native Claims 
Settlement Act) Corporations. The Service has determined that 
authorizing the Level B harassment of up to 18 polar bears and non-
serious Level A harassment of up to 3 polar bears from BLM's specified 
activities would not have any Tribal implications or ANCSA Corporation 
implications and, therefore, Government-to-Government consultation or 
Government-to-ANCSA Corporation consultation is not necessary. However, 
we invite continued discussion, either about the project and its 
impacts or about our coordination and information exchange throughout 
the IHA/POC public comment process.

Paperwork Reduction Act

    This rule does not contain any new collection of information that 
requires approval by the Office of Management and Budget (OMB) under 
the Paperwork Reduction Act of 1995 (44 U.S.C. 3501 et seq.). OMB has 
previously approved the information collection requirements associated 
with IHAs and assigned OMB Control Number 1018-0194 (expires 08/31/
2026). An agency may not conduct or sponsor, and a person is not 
required to respond to, a collection of information unless it displays 
a currently valid OMB control number.

Proposed Authorization

    We propose to authorize the nonlethal, incidental take by Level B 
harassment of up to 18 polar bears and nonlethal, incidental take by 
non-serious Level A harassment of up to 3 polar bears from the SBS 
stock of polar bears. Authorized take will be limited to disruption of 
behavioral patterns that may be caused by the oil well plugging and 
reclamation, soil sampling, snow trail, pad, and airstrip construction, 
and summer cleanup activities by BLM in the North Slope Borough of 
Alaska between the Wainwright and Oliktok Areas for 1 year from date of 
issuance. We do not anticipate or authorize any take by Level A 
serious, injury, or death to polar bears resulting from these 
activities.

A. General Conditions for the IHA for BLM

    1. Activities must be conducted in the manner described in the 
revised Request dated September 2023 (received October 5, 2023) for an 
IHA and in accordance with all applicable conditions and mitigation 
measures. The taking of polar bears whenever the required conditions, 
mitigation, monitoring, and reporting measures are not fully 
implemented as required by the IHA is prohibited. Failure to follow the 
measures specified both in the revised Request and within this proposed 
authorization may result in the modification, suspension, or revocation 
of the IHA.
    2. For the purposes of this authorization, non-serious forms of 
Level A harassment accrue to one or more cubs where project-related 
activities cause a sow to emerge from a den on or later than February 
14, and either:
    i. The operator's observations establish that the cub departed the 
denning location with the sow on or later than March 5 and that the cub 
was approximately average or greater size and/or weight, able to nurse 
uninterrupted, and able to maintain close proximity to the sow when 
traveling; or
    ii. The date of the sow and cub's departure from the denning 
location is unknown but the operator's first observation of tracks 
indicating that the sow and cub departed from the denning location 
occurs on or later than March 20.
    3. If project activities cause unauthorized take (i.e., take of 
more than 18 polar bears from the SBS stock by Level B harassment or 
more than 3 polar bears from the SBS stock by non-serious Level A 
harassment, a form of take other than Level B or non-serious Level A 
harassment, or take of 1 or more polar bears through methods not 
described in the IHA), then BLM must take the following actions:
    i. Cease its activities immediately (or reduce activities to the 
minimum level necessary to maintain safety);
    ii. Report the details of the incident to the Service within 48 
hours; and
    iii. Suspend further activities until the Service has reviewed the 
circumstances and determined whether additional mitigation measures are 
necessary to avoid further unauthorized taking.
    4. All operations managers, aircraft pilots, and vehicle operators 
must receive a copy of this IHA and maintain access to it for reference 
at all times during project work. These personnel must understand, be 
fully aware of, and be capable of implementing the conditions of the 
IHA at all times during project work.
    5. This IHA will apply to activities associated with the proposed 
project as described in this document and in BLM's revised Request. 
Changes to the proposed project without prior authorization may 
invalidate the IHA.
    6. BLM's revised Request is approved and fully incorporated into 
this IHA unless exceptions are specifically noted herein. The revised 
Request includes:
    i. BLM's original Request for an IHA, dated May 22, 2023, which 
includes BLM's Polar Bear Safety, Awareness,

[[Page 88960]]

and Interaction Plan and geospatial files;
    ii. BLM's revised Request for an IHA, dated September 2023 
(received by the Service October 5, 2023).
    7. Operators will allow Service personnel or the Service's 
designated representative to visit project work sites to monitor for 
impacts to polar bears and subsistence uses of polar bears at any time 
throughout project activities so long as it is safe to do so. 
``Operators'' are all personnel operating under BLM's authority, 
including all contractors and subcontractors.
    BLM must implement the following policies and procedures to avoid 
interactions and minimize to the greatest extent practicable any 
adverse impacts on polar bears, their habitat, and the availability of 
these marine mammals for subsistence uses.

B. General Avoidance Measures

    1. BLM must cooperate with the Service and other designated 
Federal, State, and local agencies to monitor and mitigate the impacts 
of activities on polar bears.
    2. Trained and qualified personnel must be designated to monitor 
for the presence of polar bears, initiate mitigation measures, and 
monitor, record, and report the effects of the activities on polar 
bears. BLM must provide all operators with polar bear awareness 
training prior to their participation in project activities.
    3. A Service-approved polar bear safety, awareness, and interaction 
plan must be on file with the Service Marine Mammal Management office 
and available onsite. The interaction plan must include:
    i. A description of the proposed activity (i.e., a summary of the 
plan of operations during the proposed activity);
    ii. A food, waste, and other attractants management plan;
    iii. Personnel training policies, procedures, and materials;
    iv. Site-specific polar bear interaction risk evaluation and 
mitigation measures;
    v. Polar bear avoidance and encounter procedures; and
    vi. Polar bear observation and reporting procedures.
    4. BLM must contact potentially affected subsistence communities 
and hunter organizations to discuss potential conflicts caused by the 
activities and provide the Service documentation of communications as 
described in D. Measures to Reduce Impacts to Subsistence Users.
    5. Mitigation measures for aircraft. BLM must undertake the 
following activities to limit disturbance from aircraft activities:
    i. Operators of support aircraft shall, at all times, conduct their 
activities at the maximum distance practicable from concentrations of 
polar bears.
    ii. Fixed-wing aircraft and helicopter operations within the IHA 
area must maintain a minimum altitude of 457 m (1,500 ft) above ground 
level when safe and operationally possible.
    iii. Under no circumstances, other than an emergency, will aircraft 
operate at an altitude lower than 457 m (1,500 ft) within 805 m (0.5 
mi) of a polar bear observed on ice or land measured in a straight line 
between the polar bear and the ground directly underneath the aircraft. 
Helicopters may not hover or circle above such areas or within 805 m 
(0.5 mi) of such areas. If weather conditions or operational 
constraints necessitate operation of aircraft at altitudes below 457 m 
(1,500 ft), the operator must avoid areas of known polar bear 
concentrations and should take precautions to avoid flying directly 
over or within 805 m (0.5 mi) of these areas.
    iv. Aircraft may not be operated in such a way as to separate 
individual polar bears from a group (i.e., two or more polar bears).
    6. Mitigation measures for winter activities. BLM must undertake 
the following activities to limit disturbance around known polar bear 
dens:
    i. BLM must obtain record of two aerial infrared (AIR) surveys of 
all denning habitat located within 1.6 km (1 mi) of specified 
activities in an attempt to identify maternal polar bear dens. The 
first survey obtained must occur between December 1 and December 25, 
2023, and the second survey obtained must occur between December 15, 
2023, and January 10, 2024, with at least 24 hours occurring between 
the completion of the first survey and the beginning of the second 
survey.
    ii. All observed or suspected polar bear dens must be reported to 
the Service prior to the initiation of activities.
    iii. If a suspected den site is located, BLM will immediately 
consult with the Service to analyze the data and determine if 
additional surveys or mitigation measures are required. The Service 
will determine whether the suspected den is to be treated as a putative 
den for the purposes of this IHA.
    iv. Operators must observe a 1.6-km (1-mi) operational exclusion 
zone around all putative polar bear dens during the denning season 
(November-April, or until the female and cubs leave the areas). Should 
a suspected den be discovered within 1 mile of activities, work must 
cease, and the Service contacted for guidance. The Service will 
evaluate these instances on a case-by-case basis to determine the 
appropriate action. Potential actions may range from cessation or 
modification of work to conducting additional monitoring, and BLM must 
comply with any additional measures specified.
    v. In determining the denning habitat that requires surveys, use 
the den habitat map developed by the USGS. A map of potential coastal 
polar bear denning habitat can be found at: https://www.usgs.gov/centers/asc/science/polar-bear-maternal-denning?qt-science_center_objects=4#qt-science_center_objects.

C. Monitoring

    1. Operators must provide onsite observers and implement the 
Service-approved polar bear safety, awareness, and interaction plan to 
apply mitigation measures, monitor the project's effects on polar bears 
and subsistence uses, and evaluate the effectiveness of mitigation 
measures.
    2. Onsite observers must be present during all operations and must 
record all polar bear observations, identify and document potential 
harassment, and work with personnel to implement appropriate mitigation 
measures.
    3. Operators shall cooperate with the Service and other designated 
Federal, State, and local agencies to monitor the impacts of project 
activities on polar bears. Where information is insufficient to 
evaluate the potential effects of activities on polar bears and the 
subsistence use of this species, BLM may be required to participate in 
joint monitoring efforts to address these information needs and ensure 
the least practicable impact to this resource.
    5. Operators must allow Service personnel or the Service's 
designated representative to visit project work sites to monitor 
impacts to polar bears and subsistence use at any time throughout 
project activities so long as it is safe to do so.

D. Measures To Reduce Impacts to Subsistence Users

    BLM must conduct its activities in a manner that, to the greatest 
extent practicable, minimizes adverse impacts on the availability of 
polar bears for subsistence uses.
    1. BLM will be required to develop a Service-approved POC if, 
through community consultation, concerns are raised regarding impacts 
to subsistence harvest or Alaska Native Tribes and organizations.

[[Page 88961]]

    2. If required, BLM will implement the Service-approved POC.
    3. Prior to conducting the work, BLM will take the following steps 
to reduce potential effects on subsistence harvest of polar bears:
    i. Avoid work in areas of known polar bear subsistence harvest;
    ii. Notify the cities Wainwright and Utqiagvik and the Native 
Villages of Atqasuk and Nuiqsit of the proposed project activities;
    iii. Work to resolve any concerns of potentially affected Alaska 
Native Tribal organizations and corporations regarding the project's 
effects on subsistence hunting of polar bears;
    iv. If any unresolved or ongoing concerns of potentially affected 
Alaska Native Tribal organizations and corporations remain, modify the 
POC in consultation with the Service and subsistence stakeholders to 
address these concerns; and
    v. Implement Service-required mitigation measures that will reduce 
impacts to subsistence users and their resources.

E. Reporting Requirements

    BLM must report the results of monitoring to the Service Marine 
Mammals Management office via email at: [email protected].
    1. In-season monitoring reports.
    2. Activity progress reports. BLM must:
    (i) Notify the Service at least 48 hours prior to the onset of 
activities;
    (ii) Provide the Service weekly progress reports of any significant 
changes in activities and/or locations; and
    (iii) Notify the Service within 48 hours after ending of 
activities.
    3. Polar bear observation reports. BLM must report, within 48 
hours, all observations of polar bears and potential polar bear dens 
during any project activities. Upon request, monitoring report data 
must be provided in a common electronic format (to be specified by the 
Service). Information in the observation report must include, but need 
not be limited to:
    i. Date and time of each observation;
    ii. Locations of the observer and polar bears (GPS coordinates if 
possible);
    iii. Number of polar bears;
    iv. Sex and age class--adult, subadult, cub (if known);
    v. Observer name and contact information;
    vi. Weather, visibility, and if at sea, sea state, and sea-ice 
conditions at the time of observation;
    vii. Estimated closest distance of polar bears from personnel and 
facilities;
    viii. Type of work being conducted at time of sighting;
    ix. Possible attractants present;
    x. Polar bear behavior--initial behavior when first observed (e.g., 
walking, swimming, resting, etc.);
    xi. Potential reaction--behavior of polar bear potentially in 
response to presence or activity of personnel and equipment;
    xii. Description of the encounter;
    xiii. Duration of the encounter; and
    xiv. Mitigation actions taken.
    4. Human--polar bear interaction reports. BLM must report all 
human--polar bear interaction incidents immediately, and not later than 
48 hours after the incident. Human--polar bear interactions include:
    i. Any situation in which there is a possibility for unauthorized 
take. For instance, when project activities exceed those included in an 
IHA, when a mitigation measure was required but not enacted, or when 
the injury or death of a polar bear occurs. Reports must include all 
information specified for an observation report in paragraphs (3)(i)-
(xiv) of this section E, a complete detailed description of the 
incident, and any other actions taken.
    ii. Injured, dead, or distressed polar bears that are clearly not 
associated with project activities (e.g., animals found outside the 
project area, previously wounded animals, or carcasses with moderate to 
advanced decomposition or scavenger damage) must also be reported to 
the Service immediately, and not later than 48 hours after discovery. 
Photographs, video, location information, or any other available 
documentation must be included.
    6. Final report. The results of monitoring and mitigation efforts 
identified in the marine mammal avoidance and interaction plan must be 
submitted to the Service for review within 90 days of the expiration of 
this IHA. Upon request, final report data must be provided in a common 
electronic format (to be specified by the Service). Information in the 
final report must include, but need not be limited to:
    i. Copies of all observation reports submitted under the IHA;
    ii. A summary of the observation reports;
    iii. A summary of monitoring and mitigation efforts including 
areas, total hours, total distances, and distribution;
    iv. Analysis of factors affecting the visibility and detectability 
of polar bears during monitoring;
    v. Analysis of the effectiveness of mitigation measures;
    vi. A summary and analysis of the distribution, abundance, and 
behavior of all polar bears observed; and
    vii. Estimates of take in relation to the specified activities.

Request for Public Comments

    If you wish to comment on this proposed authorization, the 
associated draft environmental assessment, or both documents, you may 
submit your comments by either of the methods described in ADDRESSES. 
Please identify whether you are commenting on the proposed 
authorization, draft environmental assessment, or both, make your 
comments as specific as possible, confine them to issues pertinent to 
the proposed authorization, and explain the reason for any changes you 
recommend. Where possible, your comments should reference the specific 
section or paragraph that you are addressing. The Service will consider 
all comments that are received before the close of the comment period 
(see DATES). The Service does not anticipate extending the public 
comment period beyond the 30 days required under section 
101(a)(5)(D)(iii) of the MMPA.
    Comments, including names and street addresses of respondents, will 
become part of the administrative record for this proposal. Before 
including your address, telephone number, email address, or other 
personal identifying information in your comment, be advised that your 
entire comment, including your personal identifying information, may be 
made publicly available at any time. While you can ask us in your 
comments to withhold from public review your personal identifying 
information, we cannot guarantee that we will be able to do so.

Peter Fasbender,
Assistant Regional Director Fisheries and Ecological Services, Alaska 
Region.
[FR Doc. 2023-28428 Filed 12-21-23; 8:45 am]
BILLING CODE 4333-15-P