Federal Register / Vol. 88, No. 246 / Tuesday, December 26, 2023 / Notices 88943 

is also thought to have impacts to 

habitats of native species, including 

eelgrass beds, along both coasts of North 

America. Recognizing the taxon’s 

potential for negative cultural, 

ecological, and economic impacts and 

its expanding geographic range, the 

ANSTF first designated EGC as an ANS 

in 1998. Following this designation, a 

EGC control committee was appointed 

by the ANSTF and subsequently 

worked, through several years of 

planning and research, to develop the 

first National Management Plan for 

European Green Crab (2002 EGC plan), 

which was approved by the ANSTF in 

2002. For 20 years, the plan guided 

natural resource managers on EGC 

management and served as a reference 

for regional plans. In June 2021, the 

ANSTF Control Subcommittee 

recommended that the 2002 EGC plan 

be updated to reflect the current 

knowledge, range, and control options 

of the species. In 2022, a working group 

was established to revise and update the 

2002 EGC plan. Input on development 

of the updated plan was sought through 

multiple forums, including email 

submissions, in-person meetings (local, 

regional, and national), regional 

listening sessions, and informal public 

comment periods. Comments received 

were addressed and, where appropriate, 

incorporated into the new draft revised 

2023 EGC plan. 

The draft 2023 EGC plan was 

submitted to the ANSTF on July 19, 

2023, and was approved to be posted in 

the Federal Register for public 

comment. Distribution of the 2023 EGC 

plan for public comment, and the 

consideration of comments received, are 

the final steps before the ANSTF can 

consider the plan for final approval 

(NANPCA; Pub. L. 101–646, 104 Stat. 

4761, 16 U.S.C. 4722). 

Proposed Updates to the 2002 

Management Plan for the European 

Green Crab 

The 2023 EGC plan proposes to 

update the 2002 plan by providing a 

more focused set of approaches for 

future management, based on significant 

changes in the distribution of EGC, new 

technologies available for identifying 

sources and mechanisms of spread, 

better information regarding the 

tradeoffs for different management 

efforts, and new methods for data 

management and sharing. The 2023 EGC 

plan also describes current strategies for 

coordinating the activities of scientists, 

resource agencies, Tribal and First 

Nation organizations, and other entities. 

The 2002 EGC plan provided significant 

information about the geographic 

distribution, mechanisms for spread, 

biology, ecology, and impacts. The 2023 

EGC plan adds new distribution 

information and summarizes recent 

research on population genetics, 

physiology, and range limits. It also 

provides detailed trapping protocols, 

recommendations for coordinating 

ongoing management efforts, and a 

summary of the legal framework and 

relevant statutes for EGC across the 

United States. The 2023 EGC plan 

includes 11 goals, 23 objectives, and 12 

specific strategies, as well as prioritized 

actions and evaluation criteria. 

The purpose of the 2023 EGC plan is 

to provide guidance for efforts to 

prevent future introductions, to rapidly 

detect and respond to new invasions of 

EGC before they become established and 

create ecological and economic damage, 

and to manage current populations that 

pose an undue threat to resources of 

importance for ecosystems and local 

cultures. This plan also serves as a 

baseline for the development and 

implementation of, as well as the 

integration with, local and regional 

plans, such as the Salish Sea 

Transboundary Action Plan for Invasive 

European Green Crab and the Early 

Detection and Rapid Response Plan for 

Invasive European Green Crab (Carcinus 

maenas) in Alaska 2023–2028 

(previously known as the Alaska Action 

Plan for Invasive European Green Crab). 

Public Availability of Comments 

Before including your address, phone 

number, email address, or other 

personal identifying information in your 

comment, you should be aware that 

your entire comment, including your 

personal identifying information, may 

be made publicly available at any time. 

While you can ask us in your comment 

to withhold your personal identifying 

information from public view, we 

cannot guarantee that we will be able to 

do so. 

Authority 

This document is published under the 

authority of the Nonindigenous Aquatic 

Nuisance Prevention and Control Act of 

1990 (NANPCA; Pub. L. 101–646, 104 

Stat. 4761, 16 U.S.C. 4701–4741), as 

reauthorized with the passage of the 

National Invasive Species Act of 1996 

(NISA; Pub. L. 104–332, 110 Stat. 4073). 

David A. Miko, 

Co-chair, Aquatic Nuisance Species Task 

Force. 

[FR Doc. 2023–28361 Filed 12–22–23; 8:45 am] 

BILLING CODE 4333–15–P 

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. 

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: 


khammond on DSKJM1Z7X2PROD with NOTICES
88944 Federal Register / Vol. 88, No. 246 / Tuesday, December 26, 2023 / Notices 

• 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 

r7mmmregulatory@fws.gov, 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-ofcontact 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 coastaldwelling 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. 


khammond on DSKJM1Z7X2PROD with NOTICES
Federal Register / Vol. 88, No. 246 / Tuesday, December 26, 2023 / Notices 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). 

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-by152 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 soilsampling 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 SnoCats, and D–7 Caterpillar Tractors. Trips 


khammond on DSKJM1Z7X2PROD with NOTICESEN26DE23.001</GPH>

71040'N 

7-0"SO'N 

70'N * Legacy well sites +~--- -- Snow trails •• , 

15 30 60Kllometers 

159"SO'W 15S"W 156''10W 154"20'W 152°30w 150"40W 

Figure 1. Specific geographic region of the proposed legacy well plugging and reclamation in the North 

Slope Borough of Alaska. 
88946 Federal Register / Vol. 88, No. 246 / Tuesday, December 26, 2023 / Notices 

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 Utqiag ̇vik to the 

well sites. A 30-mile resupply snow trail 

will follow the Barrow Gas Field Road 

from Utqiag ̇vik to the Tulageak well site, 

while a second resupply snow road 

branches off the CWAT south of 

Utqiag ̇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 Utqiag ̇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 Utqiag ̇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 (m3) (685 cubic yards 

[yd3]) 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-ftby-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 m3 (30 yd3) 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 


khammond on DSKJM1Z7X2PROD with NOTICES
Federal Register / Vol. 88, No. 246 / Tuesday, December 26, 2023 / Notices 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 fixedwing 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 

Non impulsive 

Impulsive 

Non impulsive 

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 20μPa in air and SELCUM dB re 

1 μPa in water) for impulsive and non-impulsive sounds, and unweighted peak sound pressure level in air (dB re 20μPa) and water (dB 1μPa) (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


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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; 


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• 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 icebreaking 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 

Bes ........ bears encountered in an impact 

area for the entire season. 

ac .......... coastal exposure area. 

ai .......... inland exposure area. 

ro .......... occupancy rate. 

eco ........ coastal open-water season bearencounter rate in bears/season. 

eci ......... coastal ice season bear-encounter 

rate in bears/season. 

eio ......... inland open-water season bear-encounter rate in bears/season. 

eii .......... inland ice season bear-encounter 

rate in bears/season. 

ti ........... ice season harassment rate. 

to ........... open-water season harassment 

rate. 

Bt .......... 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 


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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 nonharassment 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 ‘‘nonharassment’’ 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, midaltitude 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 openVerDate Sep<11>2014 20:25 Dec 22, 2023 Jkt 262001 PO 00000 Frm 00087 Fmt 4703 Sfmt 4703 E:\FR\FM\26DEN1.SGM 26DEN1

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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/km2.

Open-water Season (November 12–July 18) 1.48 

bears/km2.

Inland Zone Seasonal Encounter Rate 

Ice Season (July 19–November 11) 0.004 bears/km2.

Open-water Season (November 12–July 18) 0.005 

bears/km2.

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, lowaltitude travel, mid-altitude travel, highaltitude 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

Activity 

Ice season (fixed-wing aircraft 

only) 

Open-water season (helicopter only) 

Winter support Forward-looking infrared 

Tulageak 

inspection 

nd cleanup 

East Simpson 

1 inspection 

and cleanup 

West Dease 

inspection and 

cleanup 

Snow trail 

inspection 

and 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 ..................................

in Coastal Zone ........................................ 0.6688 0.1454 0.096 0.5541 1 0.077 

Proportion of Flight ..................................

in Inland Zone .......................................... 0.3312 0.8546 0.904 0.4459 0 0.923 

Total Encounter Rate ...............................

(bears/km2/season) ** .............................. 0.0347 0.0107 0.1466 0.8223 1.4800 0.1186 

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 


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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 (122/5.82,12/5.82), CC 

(252/9.52,25/9.52), and Arctic NWR (142/ 

6.32,14/6.32). 

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 


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density estimator applied to observed 

den locations, which took the form 

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 

m=81.0, s=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 8.02/5.52 and a rate 

parameter equal to 8.0/5.52; 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: 


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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 postemergence (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 postemergence period, we assigned the den 

a new time spent at the den site postemergence from a uniform distribution 

that ranged from 0 to the original 

simulated time at the den postemergence. 

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 postemergence. For each den disturbed 

during the late denning and/or postemergence 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) = b0 + b1emerge + b2depart 

where s is the probability of at least one 

cub being alive approximately 100 days 

post-emergence, b0 is the intercept 

coefficient, b1 is the coefficient 

associated with the Julian date of 

emergence (emerge), and b2 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 nonserious 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. 


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(

0.412 

- 0.413 - 0.41 X 0.1542 0.41- 2 X 0.412 + 0.413 - 0.1542 + 0.41 X 0.1542) 

p~Beta 0.1542 ' 0.1542 
Federal Register / Vol. 88, No. 246 / Tuesday, December 26, 2023 / Notices 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 (Postemergence-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) landbased 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 nonnormal 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 nonserious 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 nonserious 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 


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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

Source and type of 

harassment 

Number of 

estimated 

harassment 

events 

Bears on the surface–summer—Level B harassment 7 

Bears on the surface–winter—Level B harassment .. 6 

TABLE 8—TOTAL ESTIMATED TAKES BY

HARASSMENT OF POLAR BEARS AND

SOURCE—Continued 

Source and type of 

harassment 

Number of 

estimated 

harassment 

events 

Aircraft activities–summer 

and winter—Level B harassment ............................. 1 

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 applicantprovided 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)×100≈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 


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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)×100≈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 


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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 


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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-toGovernment 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 nonserious 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 nonserious 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, 


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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-bycase 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?qtscience_center_objects=4#qt-science_

center_objects. 

C. Monitoring 

1. Operators must provide onsite 

observers and implement the Serviceapproved 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. 


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Federal Register / Vol. 88, No. 246 / Tuesday, December 26, 2023 / Notices 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: fw7_mmm_reports@fws.gov. 

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 

DEPARTMENT OF THE INTERIOR 

National Park Service 

[NPS–WASO–NRNHL–DTS#–37150; 

PPWOCRADI0, PCU00RP14.R50000] 

National Register of Historic Places; 

Notification of Pending Nominations 

and Related Actions 

AGENCY: National Park Service, Interior. 

ACTION: Notice. 

SUMMARY: The National Park Service is 

soliciting electronic comments on the 

significance of properties nominated 

before December 16, 2023, for listing or 

related actions in the National Register 

of Historic Places. 

DATES: Comments should be submitted 

electronically by January 10, 2024. 


khammond on DSKJM1Z7X2PROD with NOTICES