[Federal Register Volume 86, Number 235 (Friday, December 10, 2021)]
[Notices]
[Pages 70451-70474]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2021-26762]


-----------------------------------------------------------------------

DEPARTMENT OF COMMERCE

National Oceanic and Atmospheric Administration

[RTID 0648-XB423]


Takes of Marine Mammals Incidental to Specified Activities; 
Taking Marine Mammals Incidental to U.S. Navy 2022 Ice Exercise 
Activities in the Arctic Ocean

AGENCY: National Marine Fisheries Service (NMFS), National Oceanic and 
Atmospheric Administration (NOAA), Commerce.

ACTION: Notice; proposed incidental harassment authorization; request 
for

[[Page 70452]]

comments on proposed authorization and possible renewal.

-----------------------------------------------------------------------

SUMMARY: NMFS has received a request from the U.S. Navy (Navy) for 
authorization to take marine mammals incidental to Ice Exercise 2022 
(ICEX22) north of Prudhoe Bay, Alaska. Pursuant to the Marine Mammal 
Protection Act (MMPA), NMFS is requesting comments on its proposal to 
issue an incidental harassment authorization (IHA) to incidentally take 
marine mammals during the specified activities. NMFS is also requesting 
comments on a possible one-time, one-year renewal that could be issued 
under certain circumstances and if all requirements are met, as 
described in Request for Public Comments at the end of this notice. 
NMFS will consider public comments prior to making any final decision 
on the issuance of the requested MMPA authorization and agency 
responses will be summarized in the final notice of our decision. The 
Navy's activities are considered military readiness activities pursuant 
to the MMPA, as amended by the National Defense Authorization Act for 
Fiscal Year 2004 (2004 NDAA).

DATES: Comments and information must be received no later than January 
10, 2022.

ADDRESSES: Comments should be addressed to Jolie Harrison, Chief, 
Permits and Conservation Division, Office of Protected Resources, 
National Marine Fisheries Service, and should be submitted via email to 
[email protected].
    Instructions: NMFS is not responsible for comments sent by any 
other method, to any other address or individual, or received after the 
end of the comment period. Comments, including all attachments, must 
not exceed a 25-megabyte file size. All comments received are a part of 
the public record and will generally be posted online at https://www.fisheries.noaa.gov/national/marine-mammal-protection/incidental-take-authorizations-military-readiness-activities without change. All 
personal identifying information (e.g., name, address) voluntarily 
submitted by the commenter may be publicly accessible. Do not submit 
confidential business information or otherwise sensitive or protected 
information.

FOR FURTHER INFORMATION CONTACT: Leah Davis, Office of Protected 
Resources, NMFS, (301) 427-8401. Electronic copies of the application 
and supporting documents, as well as a list of the references cited in 
this document, may be obtained online at: https://www.fisheries.noaa.gov/national/marine-mammal-protection/incidental-take-authorizations-military-readiness-activities. In case of problems 
accessing these documents, please call the contact listed above.

SUPPLEMENTARY INFORMATION:

Background

    The MMPA prohibits the ``take'' of marine mammals, with certain 
exceptions. Sections 101(a)(5)(A) and (D) of the MMPA (16 U.S.C. 1361 
et seq.) direct the Secretary of Commerce (as delegated to NMFS) to 
allow, upon request, the incidental, but not intentional, taking of 
small numbers of marine mammals by U.S. citizens who engage in a 
specified activity (other than commercial fishing) within a specified 
geographical region if certain findings are made and either regulations 
are proposed or, if the taking is limited to harassment, a notice of a 
proposed incidental harassment authorization is provided to the public 
for review.
    Authorization for incidental takings shall be granted if NMFS finds 
that the taking will have a negligible impact on the species or 
stock(s) and will not have an unmitigable adverse impact on the 
availability of the species or stock(s) for taking for subsistence uses 
(where relevant). Further, NMFS must prescribe the permissible methods 
of taking and other ``means of effecting the least practicable adverse 
impact'' on the affected species or stocks and their habitat, paying 
particular attention to rookeries, mating grounds, and areas of similar 
significance, and on the availability of the species or stocks for 
taking for certain subsistence uses (referred to in shorthand as 
``mitigation''); and requirements pertaining to the mitigation, 
monitoring, and reporting of the takings are set forth.
    The 2004 NDAA (Pub. L. 108-136) removed the ``small numbers'' and 
``specified geographical region'' limitations indicated above and 
amended the definition of ``harassment'' as applied to a ``military 
readiness activity.'' The activity for which incidental take of marine 
mammals is being requested addressed here qualifies as a military 
readiness activity. The definitions of all applicable MMPA statutory 
terms cited above are included in the relevant sections below.

National Environmental Policy Act

    To comply with the National Environmental Policy Act of 1969 (NEPA; 
42 U.S.C. 4321 et seq.) and NOAA Administrative Order (NAO) 216-6A, 
NMFS must review our proposed action (i.e., the issuance of an IHA) 
with respect to potential impacts on the human environment. 
Accordingly, NMFS plans to adopt the Navy's Environmental Assessment 
(EA), provided our independent evaluation of the document finds that it 
includes adequate information analyzing the effects on the human 
environment of issuing the IHA. The Navy's EA was made available for 
public comment at https://www.nepa.navy.mil/icex/ for 30 days beginning 
November 24, 2021.
    We will review all comments submitted in response to this notice 
prior to concluding our NEPA process or making a final decision on the 
IHA request.

Summary of Request

    On August 26, 2021, NMFS received a request from the Navy for an 
IHA to take marine mammals incidental to submarine training and testing 
activities including establishment of a tracking range on an ice floe 
in the Arctic Ocean, north of Prudhoe Bay, Alaska. The application was 
deemed adequate and complete on November 4, 2021. The Navy's request is 
for take of a small number of ringed seals (Pusa hispida) by Level B 
harassment only. Neither the Navy nor NMFS expects serious injury or 
mortality to result from this activity and, therefore, an IHA is 
appropriate.
    NMFS previously issued IHAs to the Navy for similar activities (83 
FR 6522; February 14, 2018, 85 FR 6518; February 5, 2020). The Navy 
complied with all the requirements (e.g., mitigation, monitoring, and 
reporting) of the previous IHAs and information regarding their 
monitoring results may be found below, in the Estimated Take section.

Description of Proposed Activity

Overview

    The Navy proposes to conduct submarine training and testing 
activities, which includes the establishment of a tracking range and 
temporary ice camp, and research in the Arctic Ocean for six weeks 
beginning in February 2022. Submarine active acoustic transmissions may 
result in occurrence of Level B harassment, including temporary hearing 
impairment (temporary threshold shift (TTS)) and behavioral harassment, 
of ringed seals.

Dates and Duration

    The specified activities would occur over approximately a six-week 
period between February and April 2022, including deployment and 
demobilization of the ice camp. The submarine training and testing 
activities would occur over approximately four weeks during the six-
week period. The proposed IHA would be effective from

[[Page 70453]]

February 1, 2022 through April 30, 2022.

Geographic Region

    The ice camp would be established approximately 100-200 nautical 
miles (nmi) north of Prudhoe Bay, Alaska. The exact location of the 
camp cannot be identified ahead of time as required conditions (e.g., 
ice cover) cannot be forecasted until exercises are expected to 
commence. Prior to the establishment of the ice camp, reconnaissance 
flights would be conducted to locate suitable ice conditions. The 
reconnaissance flights would cover an area of approximately 70,374 
square kilometers (km\2\). The actual ice camp would be no more than 
1.6 kilometers (km) in diameter (approximately 2 km\2\ in area). The 
vast majority of submarine training and testing would occur near the 
ice camp, however some submarine training and testing may occur 
throughout the deep Arctic Ocean basin near the North Pole within the 
larger Navy Activity Study Area. Figure 1 shows the locations of the 
Navy Activity Study Area and Ice Camp Study Area, collectively referred 
to in this document as the ``ICEX22 Study Area''.
BILLING CODE 3510-22-P

[[Page 70454]]

[GRAPHIC] [TIFF OMITTED] TN10DE21.018

BILLING CODE 3510-22-C

Detailed Description of Specific Activity

    The Navy proposes to conduct submarine training and testing 
activities, which includes the establishment of a tracking range and 
temporary ice camp, and research in the Arctic Ocean for six weeks 
beginning in February 2022. The activity proposed for 2022 and that is 
being evaluated for this proposed IHA-ICEX22-is part of a regular cycle 
of recurring training and testing activities that the Navy proposes to 
conduct in the Arctic. Under the Navy's proposed cycle, submarine and 
tracking range activities would be conducted biennially, but a 
temporary ice camp would be established annually, either in the ice 
camp study area (Figure 1) or on a frozen lake in Deadhorse, Alaska. 
Some of the

[[Page 70455]]

submarine training and testing may occur throughout the deep Arctic 
Ocean basin near the North Pole, within the Navy Activity Study Area 
(Figure 1). The temporary ice camps that would be constructed during 
years in which submarine training and testing is not conducted 
(referred to as ``beta camps'') would support testing and evaluation of 
Arctic equipment, but would involve fewer personnel and be shorter in 
duration than camps constructed during years in which submarine 
training and testing is conducted. Activities that the Navy proposes to 
conduct after ICEX22, including the construction of the beta camps, are 
outside of the scope of this proposed IHA, and therefore, are not 
discussed further in this document. Additional information about the 
Navy's proposed training and testing activities in the Arctic is 
available in the Navy's 2021 Draft Environmental Assessment/Overseas 
Environmental Assessment For the Ice Exercise Program, available at 
https://www.nepa.navy.mil/icex/. Only activities which may occur during 
ICEX22 are discussed in this section.
Ice Camp
    ICEX22 includes the deployment of a temporary camp situated on an 
ice floe. Reconnaissance flights to search for suitable ice conditions 
for the ice camp would depart from the public airport in Deadhorse, 
Alaska. The camp generally would consist of a command hut, dining hut, 
sleeping quarters, a powerhouse, runway, and helipad. The number of 
structures and tents would range from 15-20, and each tent is typically 
2 meters (m) by 6 m in size. The completed ice camp, including runway, 
would be approximately 1.6 km in diameter. Support equipment for the 
ice camp would include snowmobiles, gas-powered augers and saws (for 
boring holes through ice), and diesel generators. All ice camp 
materials, fuel, and food would be transported from Prudhoe Bay, 
Alaska, and delivered by air-drop from military transport aircraft 
(e.g., C-17 and C-130), or by landing at the ice camp runway (e.g., 
small twin-engine aircraft and military and commercial helicopters).
    A portable tracking range for submarine training and testing would 
be installed in the vicinity of the ice camp. Ten hydrophones, located 
on the ice and extending to 30 m below the ice, would be deployed by 
drilling or melting holes in the ice and lowering the cable down into 
the water column. Four hydrophones would be physically connected to the 
command hut via cables while the others would transmit data via radio 
frequencies. Additionally, tracking pingers would be configured aboard 
each submarine to continuously monitor the location of the submarines. 
Acoustic communications with the submarines would be used to coordinate 
the training and research schedule with the submarines. An underwater 
telephone would be used as a backup to the acoustic communications.
    Additional information about the ICEX22 ice camp is located in the 
2021 Draft Environmental Assessment/Overseas Environmental Assessment 
For the Ice Exercise Program. We have carefully reviewed this 
information and determined that activities associated with the ICEX22 
ice camp, including de minimis acoustic communications, would not 
result in incidental take of marine mammals.
Submarine Activities
    Submarine activities associated with ICEX22 generally would entail 
safety maneuvers, active sonar use, and exercise weapon use. The safety 
maneuvers and sonar use are similar to submarine activities conducted 
in other undersea environments and are being conducted in the Arctic to 
test their performance in a cold environment. The Navy anticipates the 
use of no more than 20 exercise weapons during ICEX22. The exercise 
weapons are inert (i.e., no explosives), and will be recovered by 
divers, who enter the water through melted holes, approximately 3-4 
feet wide. Submarine training and testing involves active acoustic 
transmissions, which have the potential to harass marine mammals. The 
Navy categorizes acoustic sources into ``bins'' based on frequency, 
source level, and mode of usage (U.S. Department of the Navy, 2013). 
The acoustic transmissions associated with submarine training fall 
within bins HF1 (hull-mounted submarine sonars that produce high-
frequency [greater than 10 kHz but less than 200 kHz] signals), M3 
(mid-frequency [1-10 kHz] acoustic modems greater than 190 dB re 1 
[micro]Pa), and TORP2 (heavyweight torpedo), as defined in the Navy's 
Phase III at-sea environmental documentation (see Section 3.0.3.3.1, 
Acoustic Stressors, of the 2018 AFTT Final Environmental Impact 
Statement/Overseas Environmental Impact Statement, available at https://www.nepa.navy.mil/AFTT-Phase-III/). The specifics of ICEX22 submarine 
acoustic sources are classified, including the parameters associated 
with the designated bins. Details of source use for submarine training 
are also classified. Any ICEX-specific acoustic sources not captured 
under one of the at-sea bins were modeled using source-specific 
parameters.
    Aspects of submarine training and testing activities other than 
active acoustic transmissions are fully analyzed within the 2021 Draft 
Environmental Assessment/Overseas Environmental Assessment for the Ice 
Exercise Program. We have carefully reviewed and discussed with the 
Navy these other aspects, such as vessel use and the firing of inert 
exercise weapons, and determined that aspects of submarine training and 
testing other than active acoustic transmissions would not result in 
take of marine mammals. These other aspects are therefore not discussed 
further, with the exception of potential vessel strike or exercise 
weapon strike, which are discussed in the Potential Effects of 
Specified Activities on Marine Mammals and Their Habitat section.
Research Activities
    Personnel and equipment proficiency testing and multiple research 
and development activities would be conducted as part of ICEX22. In-
water device data collection and unmanned underwater vehicle testing 
involve active acoustic transmissions, which have the potential to 
harass marine mammals; however, the acoustic transmissions that would 
be used in ICEX22 for research activities are de minimis. The Navy has 
defined de minimis sources as having the following parameters: Low 
source levels, narrow beams, downward directed transmission, short 
pulse lengths, frequencies above (outside) known marine mammal hearing 
ranges, or some combination of these factors (U.S. Department of the 
Navy, 2013). NMFS reviewed the Navy's analysis and conclusions on de 
minimis sources and finds them complete and supportable. Additional 
information about ICEX22 research activities is located in Table 2-1 of 
the 2021 Draft Environmental Assessment/Overseas Environmental 
Assessment For the Ice Exercise Program, and elsewhere in that 
document. We have carefully reviewed this information and determined 
that use of acoustic transmissions during research activities 
associated with ICEX22 would not result in incidental take of marine 
mammals. The possibility of vessel strikes caused by use of unmanned 
underwater vehicles during ICEX22 is discussed in the Potential Effects 
of Vessel Strike subsection within the Potential Effects of Specified 
Activities on Marine Mammals and Their Habitat section.
    Proposed mitigation, monitoring, and reporting measures are 
described in detail later in this document (please see

[[Page 70456]]

Proposed Mitigation and Proposed Monitoring and Reporting).

Description of Marine Mammals in the Area of Specified Activities

    Sections 3 and 4 of the application summarize available information 
regarding status and trends, distribution and habitat preferences, and 
behavior and life history of the potentially affected species. 
Additional information regarding population trends and threats may be 
found in NMFS's Stock Assessment Reports (SARs; https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessments) and more general information about these species 
(e.g., physical and behavioral descriptions) may be found on NMFS's 
website (https://www.fisheries.noaa.gov/find-species).
    Table 1 lists all species or stocks for which take is expected and 
proposed to be authorized, and summarizes information related to the 
population or stock, including regulatory status under the MMPA and the 
Endangered Species Act (ESA; 16 U.S.C. 1531 et seq.) and potential 
biological removal (PBR), where known. For taxonomy, we follow 
Committee on Taxonomy (2021). PBR is defined by the MMPA as the maximum 
number of animals, not including natural mortalities, that may be 
removed from a marine mammal stock while allowing that stock to reach 
or maintain its optimum sustainable population (as described in NMFS's 
SARs). While no serious injury or mortality is anticipated or 
authorized here, PBR and annual serious injury and mortality from 
anthropogenic sources are included in Table 1 as gross indicators of 
the status of the species and other threats.
    Marine mammal abundance estimates represent the total number of 
individuals that make up a given stock or the total number estimated 
within a particular study or survey area. NMFS's stock abundance 
estimates for most species represent the total estimate of individuals 
within the geographic area, if known, that comprises that stock. For 
some species, this geographic area may extend beyond U.S. waters. All 
managed stocks in this region are assessed in NMFS's U.S. Alaska SARs 
(Muto et al. 2021). All values presented in Table 1 are the most recent 
available at the time of publication and are available in the 2020 
Alaska SAR (Muto et al. 2021) and draft 2021 Alaska SAR (available 
online at: https://www.fisheries.noaa.gov/national/marine-mammal-protection/draft-marine-mammal-stock-assessment-reports).

                    Table 1--Species That Spatially Co-Occur With the Activity to the Degree That Take Is Reasonably Likely To Occur
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                         ESA/MMPA status;    Stock abundance  (CV;
             Common name                  Scientific name               Stock             strategic (Y/N)      Nmin; most recent       PBR     Annual M/
                                                                                                \1\          abundance survey) \2\               SI \3\
--------------------------------------------------------------------------------------------------------------------------------------------------------
Family Phocidae (earless seals):
    Ringed seal.....................  Pusa hispida...........  Arctic.................  T/D; Y              171,418,\4\ \5\ (N/A,   \6\ 4,755  \7\ 6,459
                                                                                                             158,507;\4\ \5\ 2013).
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ ESA status: Endangered (E), Threatened (T)/MMPA status: Depleted (D). Under the MMPA, a strategic stock is one for which the level of direct human-
  caused mortality exceeds PBR or which is determined to be declining and likely to be listed under the ESA within the foreseeable future. Any species
  or stock listed under the ESA is automatically designated under the MMPA as depleted and as a strategic stock.
\2\ NMFS marine mammal stock assessment reports online at: https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessments assessments. CV is coefficient of variation; Nmin is the minimum estimate of stock abundance. In some cases, CV is not applicable.
\3\ This value, found in NMFS's SARs, represents annual levels of human-caused mortality (M) plus serious injury (SI) from all sources combined (e.g.,
  commercial fisheries, ship strike).
\4\ These estimates reflect the Bering Sea population only, as reliable abundance estimates for the Chukchi Sea and Beaufort Sea are not available.
\5\ This is expected to be an underestimate of ringed seals in the Bering Sea, as the estimate was not adjusted for seals in the water at the time of
  the surveys, nor does it include ringed seals in the shorefast ice zone.
\6\ The PBR value for this stock is based on a partial stock abundance estimate, and is therefore an underestimate for the full stock.
\7\ The majority of the M/SI for this stock (6,454 of 6,459 animals) is a result of the Alaska Native subsistence harvest. While M/SI appears to exceed
  PBR, given that the reported PBR is based on a partial stock abundance estimate, and is therefore, an underestimate for the full stock, M/SI likely
  does not exceed PBR.

    As indicated in Table 1, ringed seals (with one managed stock) 
temporally and spatially co-occur with the activity to the degree that 
take is reasonably likely to occur, and we have proposed authorizing 
it. While beluga whales (Delphinapterus leucas), gray whales 
(Eschrichtius robustus), bowhead whales (Balaena mysticetus), and 
spotted seals (Phoca largha), may occur in the ICEX22 Study Area, the 
temporal and/or spatial occurrence is such that take is not expected to 
occur, and they are not discussed further beyond the explanation 
provided here. Bowhead whales are unlikely to occur in the ICEX22 Study 
Area between February and April, as they spend winter (December to 
March) in the northern Bering Sea and southern Chukchi Sea, and migrate 
north through the Chukchi Sea and Beaufort Sea during April and May 
(Muto et al. 2021). On their spring migration, the earliest that 
bowhead whales reach Point Hope in the Chukchi Sea, well south of Point 
Barrow, is late March to mid-April (Braham et al. 1980). Although the 
ice camp location is not known with certainty, the distance between 
Point Barrow and the closest edge of the Ice Camp Study Area is over 
200 km. The distance between Point Barrow and the closest edge of the 
Navy Activity Study Area is over 50 km, and the distance between Point 
Barrow and Point Hope is an additional 525 km (straight line distance); 
accordingly, bowhead whales are unlikely to occur in the ICEX22 Study 
Area before ICEX22 activities conclude. Beluga whales follow a 
migration pattern similar to bowhead whales. They typically overwinter 
in the Bering Sea and migrate north during the spring to the eastern 
Beaufort Sea where they spend the summer and early fall months (Muto et 
al. 2021). Though the beluga whale migratory path crosses through the 
ICEX22 Study Area, they are unlikely to occur in the ICEX 22 Study Area 
between February and April. Gray whales feed primarily in the Beaufort 
Sea, Chukchi Sea, and Northwestern Bering Sea during the summer and 
fall, but migrate south to winter in Baja California lagoons (Muto et 
al. 2020). Typically, northward migrating gray whales do not reach the 
Bering Sea before May or June (Frost and Karpovich 2008), after the 
ICEX22 activities would occur, and several hundred kilometers south of 
the ICEX22 Study Area. Further, gray whales are primarily bottom 
feeders (Swartz et al. 2006) in water less than 60 m deep (Pike 1962). 
Therefore, on the rare occasion that a gray whale does overwinter in 
the Beaufort Sea (Stafford et al. 2007), we would expect an 
overwintering

[[Page 70457]]

individual to remain in shallow water over the continental shelf where 
it could feed. Therefore, gray whales are not expected to occur in the 
ICEX22 Study Area during the ICEX22 activity period. Spotted seals may 
also occur in the ICEX22 Study Area during summer and fall, but they 
are not expected to occur in the ICEX22 Study Area during the ICEX22 
timeframe (Muto et al. 2020).
    Further, while the Navy requested take of bearded seals (Erignathus 
barbatus), which do occur in the ICEX22 Study Area during the project 
timeframe, NMFS does not expect that bearded seals would occur in the 
areas near the ice camp or where submarine activities involving active 
acoustics would occur, and therefore incidental take is not anticipated 
to occur and has not been proposed for authorization. Bearded seals are 
not discussed further beyond the explanation provided here. The Navy 
anticipates that the ice camp would be established 100-200 nmi (185-370 
km) north of Prudhoe Bay in water depths of 800 m or more, and also 
that submarine training and testing activities would occur in water 
depths of 800 m or more. Although bearded seals occur 20 to 100 nmi (37 
to 185 km) offshore during spring (Simpkins et al. 2003, Bengtson et 
al. 2005), they feed heavily on benthic organisms (Hamilton et al. 
2018; Hjelset et al. 1999; Fedoseev 1965), and during winter bearded 
seals are expected to select habitats where food is abundant and easily 
accessible to minimize the energy required to forage and maximize 
energy reserves in preparation for whelping, lactation, mating, and 
molting. Bearded seals are not known to dive as deep as 800 m to forage 
(Boveng and Cameron, 2013; Cameron and Boveng 2009; Cameron et al. 
2010; Gjertz et al. 2000; Kovacs 2002) and it is highly unlikely that 
they would occur near the ice camp or where the submarine activities 
would be conducted.
    In addition, the polar bear (Ursus maritimus) may be found in the 
ICEX22 Study Area. However, polar bears are managed by the U.S. Fish 
and Wildlife Service and are not considered further in this document.

Ringed Seal

    Ringed seals are the most common pinniped in the ICEX22 Study Area 
and have wide distribution in seasonally and permanently ice-covered 
waters of the Northern Hemisphere (North Atlantic Marine Mammal 
Commission 2004), though the status of the Arctic stock of ringed seals 
is unknown (Muto et al. 2020). Throughout their range, ringed seals 
have an affinity for ice-covered waters and are well adapted to 
occupying both shore-fast and pack ice (Kelly 1988c). Ringed seals can 
be found further offshore than other pinnipeds since they can maintain 
breathing holes in ice thickness greater than 2 m (Smith and Stirling 
1975). Breathing holes are maintained by ringed seals' sharp teeth and 
claws on their fore flippers. They remain in contact with ice most of 
the year and use it as a platform for molting in late spring to early 
summer, for pupping and nursing in late winter to early spring, and for 
resting at other times of the year (Muto et al. 2020).
    Ringed seals have at least two distinct types of subnivean lairs: 
Haul-out lairs and birthing lairs (Smith and Stirling 1975). Haul-out 
lairs are typically single-chambered and offer protection from 
predators and cold weather. Birthing lairs are larger, multi-chambered 
areas that are used for pupping in addition to protection from 
predators. Ringed seal populations pup on both land-fast ice as well as 
stable pack ice. Lentfer (1972) found that ringed seals north of 
Barrow, Alaska (which would be west of the ice camp), build their 
subnivean lairs on the pack ice near pressure ridges. They are also 
assumed to occur within the sea ice in the proposed ice camp area. 
Ringed seals excavate subnivean lairs in drifts over their breathing 
holes in the ice, in which they rest, give birth, and nurse their pups 
for 5-9 weeks during late winter and spring (Chapskii 1940; McLaren 
1958; Smith and Stirling 1975). Snow depths of at least 50-65 
centimeters (cm) are required for functional birth lairs (Kelly 1988b; 
Lydersen 1998; Lydersen and Gjertz 1986; Smith and Stirling 1975), and 
such depths typically occur only where 20-30 cm or more of snow has 
accumulated on flat ice and then drifted along pressure ridges or ice 
hummocks (Hammill 2008; Lydersen et al. 1990; Lydersen and Ryg 1991; 
Smith and Lydersen 1991). Ringed seal birthing season typically begins 
in March, but the majority of births occur in early April. About a 
month after parturition, mating begins in late April and early May.
    In Alaskan waters, during winter and early spring when sea ice is 
at its maximal extent, ringed seals are abundant in the northern Bering 
Sea, Norton and Kotzebue Sounds, and throughout the Chukchi and 
Beaufort Seas (Frost 1985; Kelly 1988c), including in the ICEX22 Study 
Area. Passive acoustic monitoring (PAM) of ringed seals from a high-
frequency recording package deployed at a depth of 240 m in the Chukchi 
Sea, 120 km north-northwest of Barrow, Alaska, detected ringed seals in 
the area between mid-December and late May over a four year study 
(Jones et al. 2014). With the onset of the fall freeze, ringed seal 
movements become increasingly restricted and seals will either move 
west and south with the advancing ice pack, with many seals dispersing 
throughout the Chukchi and Bering Seas, or remain in the Beaufort Sea 
(Crawford et al. 2012; Frost and Lowry 1984; Harwood et al. 2012). 
Kelly et al. (2010a) tracked home ranges for ringed seals in the 
subnivean period (using shorefast ice); the size of the home ranges 
varied from less than 1 km\2\ up to 27.9 km\2\ (median of 0.62 km\2\ 
for adult males and 0.65 km\2\ for adult females). Most (94 percent) of 
the home ranges were less than 3 km\2\ during the subnivean period 
(Kelly et al. 2010a). Near large polynyas, ringed seals maintain ranges 
up to 7,000 km\2\ during winter and 2,100 km\2\ during spring (Born et 
al. 2004). Some adult ringed seals return to the same small home ranges 
they occupied during the previous winter (Kelly et al. 2010a). The size 
of winter home ranges can vary by up to a factor of 10 depending on the 
amount of fast ice; seal movements were more restricted during winters 
with extensive fast ice, and were much less restricted where fast ice 
did not form at high levels (Harwood et al. 2015). Ringed seals may 
occur within the ICEX22 Study Area throughout the year and during the 
proposed specified activities.

Critical Habitat

    On January 8, 2021, NMFS published a revised proposed rule for the 
Designation of Critical Habitat for the Arctic Subspecies of the Ringed 
Seal (86 FR 1452). This proposed rule revises NMFS' December 9, 2014, 
proposed designation of critical habitat for the Arctic subspecies of 
the ringed seal under the ESA. NMFS identified the physical and 
biological features essential to the conservation of the species: (1) 
Snow-covered sea ice habitat suitable for the formation and maintenance 
of subnivean birth lairs used for sheltering pups during whelping and 
nursing, which is defined as areas of seasonal landfast (shorefast) ice 
and dense, stable pack ice, excluding any bottom-fast ice extending 
seaward from the coastline (typically in waters less than 2 m deep), 
that have undergone deformation and contain snowdrifts of sufficient 
depth, typically at least 54 cm deep; (2) Sea ice habitat suitable as a 
platform for basking and molting, which is defined as areas containing 
sea ice of 15 percent or more concentration, excluding any bottom-fast 
ice extending seaward from the

[[Page 70458]]

coastline (typically in waters less than 2 m deep); and (3) Primary 
prey resources to support Arctic ringed seals, which are defined to be 
Arctic cod, saffron cod, shrimps, and amphipods. The revised proposed 
critical habitat designation comprises a specific area of marine 
habitat in the Bering, Chukchi, and Beaufort seas, extending from mean 
lower low water to an offshore limit within the U.S. Exclusive Economic 
Zone, including a portion of the ICEX22 Study Area (86 FR 1452; January 
8, 2021). See the proposed ESA critical habitat rule for additional 
detail and a map of the proposed area.
    The proposed ice camp study area was excluded from the proposed 
ringed seal critical habitat because the benefits of exclusion due to 
national security impacts outweighed the benefits of inclusion of this 
area (86 FR 1452; March 9, 2021). However, as stated in NMFS' second 
revised proposed rule for the Designation of Critical Habitat for the 
Arctic Subspecies of the Ringed Seal (86 FR 1452; March 9, 2021), the 
area proposed for exclusion contains one or more of the essential 
features of the Arctic ringed seal's critical habitat, although data 
are limited to inform NMFS' assessment of the relative value of this 
area to the conservation of the species. As noted above, a portion of 
the proposed ringed seal critical habitat overlaps the larger proposed 
ICEX22 Study Area. This overlap includes the portion of the Navy 
Activity Study Area that overlaps the U.S. EEZ. However, as described 
later and in more detail in the Potential Effects of Specified 
Activities on Marine Mammals and Their Habitat section, we do not 
anticipate physical impacts to any marine mammal habitat as a result of 
the Navy's ICEX activities, including impacts to ringed seal sea ice 
habitat suitable as a platform for basking and molting and impacts on 
prey availability. Further, this proposed IHA includes mitigation 
measures, as described in the Proposed Mitigation section, that would 
minimize or prevent impacts to sea ice habitat suitable for the 
formation and maintenance of subnivean birth lairs.

Ice Seal Unusual Mortality Event

    Since June 1, 2018, elevated strandings of ringed seals, bearded 
seals, and spotted seals have occurred in the Bering and Chukchi Seas. 
This event has been declared an Unusual Mortality Event (UME). A UME is 
defined under the MMPA as a stranding that is unexpected; involves a 
significant die-off of any marine mammal population; and demands 
immediate response. From June 1, 2018 to November 17, 2021, there have 
been at least 368 dead seals reported; 106 bearded seals, 95 ringed 
seals, 62 spotted seals, and 105 unidentified seals. All age classes of 
seals have been reported stranded, and a subset of seals have been 
sampled for genetics and harmful algal bloom exposure, with a few 
having histopathology collected. Results are pending, and the cause of 
the UME remains unknown.
    There was a previous UME involving ice seals (which, in Alaska, 
includes bearded seals, ringed seals, ribbon seals, and spotted seals) 
from 2011 to 2016, which was most active in 2011-2012. A minimum of 657 
seals were affected. The UME investigation determined that some of the 
clinical signs were due to an abnormal molt, but a definitive cause of 
death for the UME was never determined. The number of stranded ice 
seals involved in this current UME, and their physical characteristics, 
is not at all similar to the 2011-2016 UME, as the seals in the current 
UME are not exhibiting hair loss or skin lesions, which were a primary 
finding in the 2011-2016 UME. The investigation into the cause of the 
current UME is ongoing.
    As part of the UME investigation process, NOAA has assembled an 
independent team of scientists to coordinate with the Working Group on 
Marine Mammal Unusual Mortality Events to review the data collected, 
sample stranded seals, and determine the next steps for the 
investigation. More detailed information is available at: https://www.fisheries.noaa.gov/alaska/marine-life-distress/2018-2021-ice-seal-unusual-mortality-event-alaska.

Marine Mammal Hearing

    Hearing is the most important sensory modality for marine mammals 
underwater, and exposure to anthropogenic sound can have deleterious 
effects. To appropriately assess the potential effects of exposure to 
sound, it is necessary to understand the frequency ranges marine 
mammals are able to hear. Current data indicate that not all marine 
mammal species have equal hearing capabilities (e.g., Richardson et al. 
1995; Wartzok and Ketten, 1999; Au and Hastings, 2008). To reflect 
this, Southall et al. (2007) recommended that marine mammals be divided 
into functional hearing groups based on directly measured or estimated 
hearing ranges on the basis of available behavioral response data, 
audiograms derived using auditory evoked potential techniques, 
anatomical modeling, and other data. Note that no direct measurements 
of hearing ability have been successfully completed for mysticetes 
(i.e., low-frequency cetaceans). Subsequently, NMFS (2018) described 
generalized hearing ranges for these marine mammal hearing groups. 
Generalized hearing ranges were chosen based on the approximately 65 
decibel (dB) threshold from the normalized composite audiograms, with 
the exception for lower limits for low-frequency cetaceans where the 
lower bound was deemed to be biologically implausible and the lower 
bound from Southall et al. (2007) retained. Marine mammal hearing 
groups and their associated hearing ranges are provided in Table 2.

                  Table 2--Marine Mammal Hearing Groups
                              [NMFS, 2018]
------------------------------------------------------------------------
            Hearing group                 Generalized hearing range *
------------------------------------------------------------------------
Low-frequency (LF) cetaceans (baleen  7 Hz to 35 kHz.
 whales).
Mid-frequency (MF) cetaceans          150 Hz to 160 kHz.
 (dolphins, toothed whales, beaked
 whales, bottlenose whales).
High-frequency (HF) cetaceans (true   275 Hz to 160 kHz.
 porpoises, Kogia, river dolphins,
 cephalorhynchid, Lagenorhynchus
 cruciger and L. australis).
Phocid pinnipeds (PW) (underwater)    50 Hz to 86 kHz.
 (true seals).
Otariid pinnipeds (OW) (underwater)   60 Hz to 39 kHz.
 (sea lions and fur seals).
------------------------------------------------------------------------
* Represents the generalized hearing range for the entire group as a
  composite (i.e., all species within the group), where individual
  species' hearing ranges are typically not as broad. Generalized
  hearing range chosen based on ~65 dB threshold from normalized
  composite audiogram, with the exception for lower limits for LF
  cetaceans (Southall et al. 2007) and PW pinniped (approximation).


[[Page 70459]]

    The pinniped functional hearing group was modified from Southall et 
al. (2007) on the basis of data indicating that phocid species have 
consistently demonstrated an extended frequency range of hearing 
compared to otariids, especially in the higher frequency range 
(Hemil[auml] et al. 2006; Kastelein et al. 2009; Reichmuth and Holt, 
2013).
    For more detail concerning these groups and associated frequency 
ranges, please see NMFS (2018) for a review of available information. 
Only ringed seals (a phocid pinniped species) have the reasonable 
potential to co-occur with the proposed ICEX22 activities.

Potential Effects of Specified Activities on Marine Mammals and Their 
Habitat

    This section includes a summary and discussion of the ways that 
components of the specified activity may impact marine mammals and 
their habitat. The Estimated Take section later in this document 
includes a quantitative analysis of the number of individuals that are 
expected to be taken by this activity. The Negligible Impact Analysis 
and Determination section considers the content of this section, the 
Estimated Take section, and the Proposed Mitigation section, to draw 
conclusions regarding the likely impacts of these activities on the 
reproductive success or survivorship of individuals and how those 
impacts on individuals are likely to impact marine mammal species or 
stocks.

Description of Sound Sources

    Here, we first provide background information on marine mammal 
hearing before discussing the potential effects of the use of active 
acoustic sources on marine mammals.
    Sound travels in waves, the basic components of which are 
frequency, wavelength, velocity, and amplitude. Frequency is the number 
of pressure waves that pass by a reference point per unit of time and 
is measured in Hz or cycles per second. Wavelength is the distance 
between two peaks of a sound wave; lower frequency sounds have longer 
wavelengths than higher frequency sounds and attenuate (decrease) more 
rapidly in shallower water. Amplitude is the height of the sound 
pressure wave or the `loudness' of a sound and is typically measured 
using the dB scale. A dB is the ratio between a measured pressure (with 
sound) and a reference pressure (sound at a constant pressure, 
established by scientific standards). It is a logarithmic unit that 
accounts for large variations in amplitude; therefore, relatively small 
changes in dB ratings correspond to large changes in sound pressure. 
When referring to sound pressure levels (SPLs; the sound force per unit 
area), sound is referenced in the context of underwater sound pressure 
to 1 microPascal ([mu]Pa). One pascal is the pressure resulting from a 
force of one newton exerted over an area of one square meter. The 
source level (SL) represents the sound level at a distance of 1 m from 
the source (referenced to 1 [mu]Pa). The received level is the sound 
level at the listener's position. Note that all underwater sound levels 
in this document are referenced to a pressure of 1 [micro]Pa.
    Root mean square (RMS) is the quadratic mean sound pressure over 
the duration of an impulse. RMS is calculated by squaring all of the 
sound amplitudes, averaging the squares, and then taking the square 
root of the average (Urick 1983). RMS accounts for both positive and 
negative values; squaring the pressures makes all values positive so 
that they may be accounted for in the summation of pressure levels 
(Hastings and Popper 2005). This measurement is often used in the 
context of discussing behavioral effects, in part because behavioral 
effects, which often result from auditory cues, may be better expressed 
through averaged units than by peak pressures.
    When underwater objects vibrate or activity occurs, sound-pressure 
waves are created. These waves alternately compress and decompress the 
water as the sound wave travels. Underwater sound waves radiate in all 
directions away from the source (similar to ripples on the surface of a 
pond), except in cases where the source is directional. The 
compressions and decompressions associated with sound waves are 
detected as changes in pressure by aquatic life and man-made sound 
receptors such as hydrophones.
    Even in the absence of sound from the specified activity, the 
underwater environment is typically loud due to ambient sound. Ambient 
sound is defined as environmental background sound levels lacking a 
single source or point (Richardson et al. 1995), and the sound level of 
a region is defined by the total acoustical energy being generated by 
known and unknown sources. These sources may include physical (e.g., 
waves, earthquakes, ice, atmospheric sound), biological (e.g., sounds 
produced by marine mammals, fish, and invertebrates), and anthropogenic 
sound (e.g., vessels, dredging, aircraft, construction). A number of 
sources contribute to ambient sound, including the following 
(Richardson et al. 1995):
     Wind and waves: The complex interactions between wind and 
water surface, including processes such as breaking waves and wave-
induced bubble oscillations and cavitation, are a main source of 
naturally occurring ambient noise for frequencies between 200 Hz and 50 
kHz (Mitson, 1995). Under sea ice, noise generated by ice deformation 
and ice fracturing may be caused by thermal, wind, drift, and current 
stresses (Roth et al. 2012);
     Precipitation: Sound from rain and hail impacting the 
water surface can become an important component of total noise at 
frequencies above 500 Hz, and possibly down to 100 Hz during quiet 
times. In the ice-covered ICEX22 Study Area, precipitation is unlikely 
to impact ambient sound;
     Biological: Marine mammals can contribute significantly to 
ambient noise levels, as can some fish and shrimp. The frequency band 
for biological contributions is from approximately 12 Hz to over 100 
kHz; and
     Anthropogenic: Sources of ambient noise related to human 
activity include transportation (surface vessels and aircraft), 
dredging and construction, oil and gas drilling and production, seismic 
surveys, sonar, explosions, and ocean acoustic studies. Shipping noise 
typically dominates the total ambient noise for frequencies between 20 
and 300 Hz. In general, the frequencies of anthropogenic sounds are 
below 1 kHz and, if higher frequency sound levels are created, they 
attenuate rapidly (Richardson et al. 1995). Sound from identifiable 
anthropogenic sources other than the activity of interest (e.g., a 
passing vessel) is sometimes termed background sound, as opposed to 
ambient sound. Anthropogenic sources are unlikely to significantly 
contribute to ambient underwater noise during the late winter and early 
spring in the ICEX22 Study Area as most anthropogenic activities would 
not be active due to ice cover (e.g. seismic surveys, shipping; Roth et 
al. 2012).
    The sum of the various natural and anthropogenic sound sources at 
any given location and time--which comprise ``ambient'' or 
``background'' sound--depends not only on the source levels (as 
determined by current weather conditions and levels of biological and 
shipping activity) but also on the ability of sound to propagate 
through the environment. In turn, sound propagation is dependent on the 
spatially and temporally varying properties of the water column and sea 
floor, and is frequency-dependent. As a result of the dependence on a 
large number of varying factors, ambient sound levels can be expected 
to vary widely over both coarse and fine spatial and temporal scales. 
Sound levels at a given frequency and location can vary by 10-20 dB 
from day to day

[[Page 70460]]

(Richardson et al. 1995). The result is that, depending on the source 
type and its intensity, sound from the specified activity may be a 
negligible addition to the local environment or could form a 
distinctive signal that may affect marine mammals.
    Underwater sounds fall into one of two general sound types: 
Impulsive and non-impulsive (defined in the following paragraphs). The 
distinction between these two sound types is important because they 
have differing potential to cause physical effects, particularly with 
regard to hearing (e.g., Ward, 1997 in Southall et al. 2007). Please 
see Southall et al. (2007) for an in-depth discussion of these 
concepts.
    Impulsive sound sources (e.g., explosions, gunshots, sonic booms, 
impact pile driving) produce signals that are brief (typically 
considered to be less than one second), broadband, atonal transients 
(ANSI 1986; Harris 1998; NIOSH 1998; ISO 2016; ANSI 2005) and occur 
either as isolated events or repeated in some succession. Impulsive 
sounds are all characterized by a relatively rapid rise from ambient 
pressure to a maximal pressure value followed by a rapid decay period 
that may include a period of diminishing, oscillating maximal and 
minimal pressures, and generally have an increased capacity to induce 
physical injury as compared with sounds that lack these features. There 
are no pulsed sound sources associated with any planned ICEX22 
activities.
    Non-impulsive sounds can be tonal, narrowband, or broadband, brief 
or prolonged, and may be either continuous or non-continuous (ANSI 
1995; NIOSH 1998). Some of these non-impulsive sounds can be transient 
signals of short duration but without the essential properties of 
pulses (e.g., rapid rise time). Examples of non-impulsive sounds 
include those produced by vessels, aircraft, machinery operations such 
as drilling or dredging, vibratory pile driving, and active sonar 
sources (such as those planned for use by the Navy as part of the 
proposed ICEX22 activities) that intentionally direct a sound signal at 
a target that is reflected back in order to discern physical details 
about the target.
    Modern sonar technology includes a variety of sonar sensor and 
processing systems. In concept, the simplest active sonar emits sound 
waves, or ``pings,'' sent out in multiple directions, and the sound 
waves then reflect off of the target object in multiple directions. The 
sonar source calculates the time it takes for the reflected sound waves 
to return; this calculation determines the distance to the target 
object. More sophisticated active sonar systems emit a ping and then 
rapidly scan or listen to the sound waves in a specific area. This 
provides both distance to the target and directional information. Even 
more advanced sonar systems use multiple receivers to listen to echoes 
from several directions simultaneously and provide efficient detection 
of both direction and distance. In general, when sonar is in use, the 
sonar `pings' occur at intervals, referred to as a duty cycle, and the 
signals themselves are very short in duration. For example, sonar that 
emits a 1-second ping every 10 seconds has a 10 percent duty cycle. The 
Navy's most powerful hull-mounted mid-frequency sonar source used in 
ICEX activities typically emits a 1-second ping every 50 seconds 
representing a 2 percent duty cycle. The Navy utilizes sonar systems 
and other acoustic sensors in support of a variety of mission 
requirements.

Acoustic Impacts

    Please refer to the information given previously regarding sound, 
characteristics of sound types, and metrics used in this document. 
Anthropogenic sounds cover a broad range of frequencies and sound 
levels and can have a range of highly variable impacts on marine life, 
from none or minor to potentially severe responses, depending on 
received levels, duration of exposure, behavioral context, and various 
other factors. The potential effects of underwater sound from active 
acoustic sources can include one or more of the following: Temporary or 
permanent hearing impairment, non-auditory physical or physiological 
effects, behavioral disturbance, stress, and masking (Richardson et al. 
1995; Gordon et al. 2004; Nowacek et al. 2007; Southall et al. 2007; 
Gotz et al. 2009). The degree of effect is intrinsically related to the 
signal characteristics, received level, distance from the source, and 
duration of the sound exposure. In general, sudden, high level sounds 
can cause hearing loss, as can longer exposures to lower level sounds. 
Temporary or permanent loss of hearing will occur almost exclusively 
for noise within an animal's hearing range. In this section, we first 
describe specific manifestations of acoustic effects before providing 
discussion specific to the proposed activities in the next section.
    Permanent Threshold Shift--Marine mammals exposed to high-intensity 
sound, or to lower-intensity sound for prolonged periods, can 
experience hearing threshold shift (TS), which is the loss of hearing 
sensitivity at certain frequency ranges (Finneran 2015). TS can be 
permanent (PTS), in which case the loss of hearing sensitivity is not 
fully recoverable, or temporary (TTS), in which case the animal's 
hearing threshold would recover over time (Southall et al. 2007). 
Repeated sound exposure that leads to TTS could cause PTS. In severe 
cases of PTS, there can be total or partial deafness, while in most 
cases the animal has an impaired ability to hear sounds in specific 
frequency ranges (Kryter 1985).
    When PTS occurs, there is physical damage to the sound receptors in 
the ear (i.e., tissue damage), whereas TTS represents primarily tissue 
fatigue and is reversible (Southall et al. 2007). In addition, other 
investigators have suggested that TTS is within the normal bounds of 
physiological variability and tolerance and does not represent physical 
injury (e.g., Ward 1997). Therefore, NMFS does not consider TTS to 
constitute auditory injury.
    Relationships between TTS and PTS thresholds have not been studied 
in marine mammals--PTS data exists only for a single harbor seal 
(Kastak et al. 2008)--but are assumed to be similar to those in humans 
and other terrestrial mammals. PTS typically occurs at exposure levels 
at least several dB above (a 40-dB threshold shift approximates PTS 
onset; e.g., Kryter et al. 1966; Miller, 1974) those inducing mild TTS 
(a 6-dB threshold shift approximates TTS onset; e.g., Southall et al. 
2007). Based on data from terrestrial mammals, a precautionary 
assumption is that the PTS thresholds for impulse sounds (such as 
impact pile driving pulses as received close to the source) are at 
least six dB higher than the TTS threshold on a peak-pressure basis and 
PTS cumulative sound exposure level (SEL) thresholds are 15 to 20 dB 
higher than TTS cumulative SEL thresholds (Southall et al. 2007).
    Temporary Threshold Shift--TTS is the mildest form of hearing 
impairment that can occur during exposure to sound (Kryter, 1985). 
While experiencing TTS, the hearing threshold rises, and a sound must 
be at a higher level in order to be heard. In terrestrial and marine 
mammals, TTS can last from minutes or hours to days (in cases of strong 
TTS). In many cases, hearing sensitivity recovers rapidly after 
exposure to the sound ends.
    Marine mammal hearing plays a critical role in communication with 
conspecifics, and interpretation of environmental cues for purposes 
such as predator avoidance and prey capture. Depending on the degree 
(elevation of threshold in dB), duration (i.e., recovery time), and 
frequency range of TTS, and the context in which it is experienced, TTS 
can have effects on marine mammals ranging from discountable to

[[Page 70461]]

serious. For example, a marine mammal may be able to readily compensate 
for a brief, relatively small amount of TTS in a non-critical frequency 
range that occurs during a time where ambient noise is lower and there 
are not as many competing sounds present. Alternatively, a larger 
amount and longer duration of TTS sustained during time when 
communication is critical for successful mother/calf interactions could 
have more serious impacts.
    Currently, TTS data only exist for four species of cetaceans 
(bottlenose dolphin (Tursiops truncatus), beluga whale, harbor porpoise 
(Phocoena phocoena), and Yangtze finless porpoise (Neophocoena 
asiaeorientalis)) and three species of pinnipeds (northern elephant 
seal (Mirounga angustirostris), harbor seal (Phoca vitulina), and 
California sea lion (Zalophus californianus)) exposed to a limited 
number of sound sources (i.e., mostly tones and octave-band noise) in 
laboratory settings (Finneran 2015). TTS was not observed in trained 
spotted and ringed seals exposed to impulsive noise at levels matching 
previous predictions of TTS onset (Reichmuth et al. 2016). In general, 
harbor seals and harbor porpoises have a lower TTS onset than other 
measured pinniped or cetacean species. Additionally, the existing 
marine mammal TTS data come from a limited number of individuals within 
these species. There are no data available on noise-induced hearing 
loss for mysticetes. For summaries of data on TTS in marine mammals or 
for further discussion of TTS onset thresholds, please see Southall et 
al. (2007), Finneran and Jenkins (2012), and Finneran (2015).
    Behavioral effects--Behavioral disturbance may include a variety of 
effects, including subtle changes in behavior (e.g., minor or brief 
avoidance of an area or changes in vocalizations), more conspicuous 
changes in similar behavioral activities, and more sustained and/or 
potentially severe reactions, such as displacement from or abandonment 
of high-quality habitat. Behavioral responses to sound are highly 
variable and context-specific and any reactions depend on numerous 
intrinsic and extrinsic factors (e.g., species, state of maturity, 
experience, current activity, reproductive state, auditory sensitivity, 
time of day), as well as the interplay between factors (e.g., 
Richardson et al. 1995; Wartzok et al. 2003; Southall et al. 2007; 
Weilgart, 2007; Archer et al. 2010). Behavioral reactions can vary not 
only among individuals but also within an individual, depending on 
previous experience with a sound source, context, and numerous other 
factors (Ellison et al. 2012), and can vary depending on 
characteristics associated with the sound source (e.g., whether it is 
moving or stationary, number of sources, distance from the source). 
Please see Appendices B-C of Southall et al. (2007) for a review of 
studies involving marine mammal behavioral responses to sound.
    Habituation can occur when an animal's response to a stimulus wanes 
with repeated exposure, usually in the absence of unpleasant associated 
events (Wartzok et al. 2003). Animals are most likely to habituate to 
sounds that are predictable and unvarying. It is important to note that 
habituation is appropriately considered as a ``progressive reduction in 
response to stimuli that are perceived as neither aversive nor 
beneficial,'' rather than as, more generally, moderation in response to 
human disturbance (Bejder et al. 2009). The opposite process is 
sensitization, when an unpleasant experience leads to subsequent 
responses, often in the form of avoidance, at a lower level of 
exposure. As noted, behavioral state may affect the type of response. 
For example, animals that are resting may show greater behavioral 
change in response to disturbing sound levels than animals that are 
highly motivated to remain in an area for feeding (Richardson et al. 
1995; NRC 2003; Wartzok et al. 2003). Controlled experiments with 
captive marine mammals have shown pronounced behavioral reactions, 
including avoidance of loud sound sources (Ridgway et al. 1997; 
Finneran et al. 2003). Observed responses of wild marine mammals to 
loud impulsive sound sources (typically seismic airguns or acoustic 
harassment devices) have been varied but often consist of avoidance 
behavior or other behavioral changes suggesting discomfort (Morton and 
Symonds 2002; see also Richardson et al. 1995; Nowacek et al. 2007).
    Available studies show wide variation in response to underwater 
sound; therefore, it is difficult to predict specifically how any given 
sound in a particular instance might affect marine mammals perceiving 
the signal. If a marine mammal does react briefly to an underwater 
sound by changing its behavior or moving a small distance, the impacts 
of the change are unlikely to be significant to the individual, let 
alone the stock or population. However, if a sound source displaces 
marine mammals from an important feeding or breeding area for a 
prolonged period, impacts on individuals and populations could be 
significant (e.g., Lusseau and Bejder 2007; Weilgart 2007; NRC 2003). 
However, there are broad categories of potential response, which we 
describe in greater detail here, that include alteration of dive 
behavior, alteration of foraging behavior, effects to breathing, 
interference with or alteration of vocalization, avoidance, and flight.
    Changes in dive behavior can vary widely, and may consist of 
increased or decreased dive times and surface intervals as well as 
changes in the rates of ascent and descent during a dive (e.g., Frankel 
and Clark 2000; Costa et al. 2003; Ng and Leung, 2003; Nowacek et al. 
2004; Goldbogen et al. 2013). Variations in dive behavior may reflect 
interruptions in biologically significant activities (e.g., foraging) 
or they may be of little biological significance. The impact of an 
alteration to dive behavior resulting from an acoustic exposure depends 
on what the animal is doing at the time of the exposure and the type 
and magnitude of the response.
    Disruption of feeding behavior can be difficult to correlate with 
anthropogenic sound exposure, so it is usually inferred by observed 
displacement from known foraging areas, the appearance of secondary 
indicators (e.g., bubble nets or sediment plumes), or changes in dive 
behavior. As for other types of behavioral response, the frequency, 
duration, and temporal pattern of signal presentation, as well as 
differences in species sensitivity, are likely contributing factors to 
differences in response in any given circumstance (e.g., Croll et al. 
2001; Nowacek et al. 2004; Madsen et al. 2006; Yazvenko et al. 2007). A 
determination of whether foraging disruptions incur fitness 
consequences would require information on or estimates of the energetic 
requirements of the affected individuals and the relationship between 
prey availability, foraging effort and success, and the life history 
stage of the animal.
    Variations in respiration naturally vary with different behaviors 
and alterations to breathing rate as a function of acoustic exposure 
can be expected to co-occur with other behavioral reactions, such as a 
flight response or an alteration in diving. However, respiration rates 
in and of themselves may be representative of annoyance or an acute 
stress response. Various studies have shown that respiration rates may 
either be unaffected or could increase, depending on the species and 
signal characteristics, again highlighting the importance in 
understanding species differences in the tolerance of underwater noise 
when determining the potential for impacts resulting from anthropogenic 
sound

[[Page 70462]]

exposure (e.g., Kastelein et al. 2001, 2005b, 2006; Gailey et al. 
2007).
    Marine mammals vocalize for different purposes and across multiple 
modes, such as whistling, echolocation click production, calling, and 
singing. Changes in vocalization behavior in response to anthropogenic 
noise can occur for any of these modes and may result from a need to 
compete with an increase in background noise or may reflect increased 
vigilance or a startle response. For example, in the presence of 
potentially masking signals, humpback whales and killer whales have 
been observed to increase the length of their songs (Miller et al. 
2000; Fristrup et al. 2003; Foote et al. 2004), while right whales have 
been observed to shift the frequency content of their calls upward 
while reducing the rate of calling in areas of increased anthropogenic 
noise (Parks et al. 2007). In some cases, animals may cease sound 
production during production of aversive signals (Bowles et al. 1994).
    Avoidance is the displacement of an individual from an area or 
migration path as a result of the presence of a sound or other 
stressors, and is one of the most obvious manifestations of disturbance 
in marine mammals (Richardson et al. 1995). For example, gray whales 
are known to change direction--deflecting from customary migratory 
paths--in order to avoid noise from seismic surveys (Malme et al. 
1984). Avoidance may be short-term, with animals returning to the area 
once the noise has ceased (e.g., Bowles et al. 1994; Goold, 1996; 
Morton and Symonds, 2002; Gailey et al. 2007). Longer-term displacement 
is possible, however, which may lead to changes in abundance or 
distribution patterns of the affected species in the affected region if 
habituation to the presence of the sound does not occur (e.g., 
Blackwell et al. 2004; Bejder et al. 2006).
    A flight response is a dramatic change in normal movement to a 
directed and rapid movement away from the perceived location of a sound 
source. The flight response differs from other avoidance responses in 
the intensity of the response (e.g., directed movement, rate of 
travel). Relatively little information on flight responses of marine 
mammals to anthropogenic signals exist, although observations of flight 
responses to the presence of predators have occurred (Connor and 
Heithaus 1996). The result of a flight response could range from brief, 
temporary exertion and displacement from the area where the signal 
provokes flight to, in extreme cases, marine mammal strandings (Evans 
and England 2001). However, it should be noted that response to a 
perceived predator does not necessarily invoke flight (Ford and Reeves 
2008), and whether individuals are solitary or in groups may influence 
the response.
    Behavioral disturbance can also impact marine mammals in more 
subtle ways. Increased vigilance may result in costs related to 
diversion of focus and attention (i.e., when a response consists of 
increased vigilance, it may come at the cost of decreased attention to 
other critical behaviors such as foraging or resting). These effects 
have generally not been demonstrated for marine mammals, but studies 
involving fish and terrestrial animals have shown that increased 
vigilance may substantially reduce feeding rates (e.g., Beauchamp and 
Livoreil, 1997; Fritz et al. 2002; Purser and Radford 2011). In 
addition, chronic disturbance can cause population declines through 
reduction of fitness (e.g., decline in body condition) and subsequent 
reduction in reproductive success, survival, or both (e.g., Harrington 
and Veitch 1992; Daan et al. 1996; Bradshaw et al. 1998). However, 
Ridgway et al. (2006) reported that increased vigilance in bottlenose 
dolphins exposed to sound over a five-day period did not cause any 
sleep deprivation or stress effects.
    Many animals perform vital functions, such as feeding, resting, 
traveling, and socializing, on a diel cycle (24-hour cycle). Disruption 
of such functions resulting from reactions to stressors such as sound 
exposure are more likely to be significant if they last more than one 
diel cycle or recur on subsequent days (Southall et al. 2007). 
Consequently, a behavioral response lasting less than one day and not 
recurring on subsequent days is not considered particularly severe 
unless it could directly affect reproduction or survival (Southall et 
al. 2007). Note that there is a difference between multi-day 
substantive behavioral reactions and multi-day anthropogenic 
activities. For example, just because an activity lasts for multiple 
days does not necessarily mean that individual animals are either 
exposed to activity-related stressors for multiple days or, further, 
exposed in a manner resulting in sustained multi-day substantive 
behavioral responses.
    For non-impulsive sounds (i.e., similar to the sources used during 
the proposed specified activities), data suggest that exposures of 
pinnipeds to received levels between 90 and 140 dB re 1 [mu]Pa do not 
elicit strong behavioral responses; no data were available for 
exposures at higher received levels for Southall et al. (2007) to 
include in the severity scale analysis. Reactions of harbor seals were 
the only available data for which the responses could be ranked on the 
severity scale. For reactions that were recorded, the majority (17 of 
18 individuals/groups) were ranked on the severity scale as a 4 
(defined as moderate change in movement, brief shift in group 
distribution, or moderate change in vocal behavior) or lower; the 
remaining response was ranked as a 6 (defined as minor or moderate 
avoidance of the sound source). Additional data on hooded seals 
(Cystophora cristata) indicate avoidance responses to signals above 
160-170 dB re 1 [mu]Pa (Kvadsheim et al. 2010), and data on gray seals 
(Halichoerus grypus) and harbor seals indicate avoidance response at 
received levels of 135-144 dB re 1 [mu]Pa (G[ouml]tz et al. 2010). In 
each instance where food was available, which provided the seals 
motivation to remain near the source, habituation to the signals 
occurred rapidly. In the same study, it was noted that habituation was 
not apparent in wild seals where no food source was available 
(G[ouml]tz et al. 2010). This implies that the motivation of the animal 
is necessary to consider in determining the potential for a reaction. 
In one study that aimed to investigate the under-ice movements and 
sensory cues associated with under-ice navigation of ice seals, 
acoustic transmitters (60-69 kHz at 159 dB re 1 [mu]Pa at 1 m) were 
attached to ringed seals (Wartzok et al. 1992a; Wartzok et al. 1992b). 
An acoustic tracking system then was installed in the ice to receive 
the acoustic signals and provide real-time tracking of ice seal 
movements. Although the frequencies used in this study are at the upper 
limit of ringed seal hearing, the ringed seals appeared unaffected by 
the acoustic transmissions, as they were able to maintain normal 
behaviors (e.g., finding breathing holes).
    Seals exposed to non-impulsive sources with a received sound 
pressure level within the range of calculated exposures for ICEX 
activities (142-193 dB re 1 [mu]Pa), have been shown to change their 
behavior by modifying diving activity and avoidance of the sound source 
(G[ouml]tz et al. 2010; Kvadsheim et al. 2010). Although a minor change 
to a behavior may occur as a result of exposure to the sources in the 
proposed specified activities, these changes would be within the normal 
range of behaviors for the animal (e.g., the use of a breathing hole 
further from the source, rather than one closer to the source, would be 
within the normal range of behavior; Kelly et al. 1988).
    Adult ringed seals spend up to 20 percent of the time in subnivean 
lairs during the winter season (Kelly et al.

[[Page 70463]]

2010a). Ringed seal pups spend about 50 percent of their time in the 
lair during the nursing period (Lydersen and Hammill 1993). During the 
warm season ringed seals haul out on the ice. In a study of ringed seal 
haulout activity by Born et al. (2002), ringed seals spent 25-57 
percent of their time hauled out in June, which is during their molting 
season. Ringed seal lairs are typically used by individual seals 
(haulout lairs) or by a mother with a pup (birthing lairs); large lairs 
used by many seals for hauling out are rare (Smith and Stirling 1975). 
If the non-impulsive acoustic transmissions are heard and are perceived 
as a threat, ringed seals within subnivean lairs could react to the 
sound in a similar fashion to their reaction to other threats, such as 
polar bears (their primary predators). Responses of ringed seals to a 
variety of human-induced sounds (e.g., helicopter noise, snowmobiles, 
dogs, people, and seismic activity) have been variable; some seals 
entered the water and some seals remained in the lair. However, 
according to Kelly et al. (1988), in all instances in which observed 
seals departed lairs in response to noise disturbance, they 
subsequently reoccupied the lair.
    Ringed seal mothers have a strong bond with their pups and may 
physically move their pups from the birth lair to an alternate lair to 
avoid predation, sometimes risking their lives to defend their pups 
from potential predators (Smith 1987). If a ringed seal mother 
perceives the proposed acoustic sources as a threat, the network of 
multiple birth and haulout lairs allows the mother and pup to move to a 
new lair (Smith and Hammill 1981; Smith and Stirling 1975). The 
acoustic sources from these proposed specified activities are not 
likely to impede a ringed seal from finding a breathing hole or lair, 
as captive seals have been found to primarily use vision to locate 
breathing holes and no effect to ringed seal vision would occur from 
the acoustic disturbance (Elsner et al. 1989; Wartzok et al. 1992a). It 
is anticipated that a ringed seal would be able to relocate to a 
different breathing hole relatively easily without impacting their 
normal behavior patterns.
    Stress responses--An animal's perception of a threat may be 
sufficient to trigger stress responses consisting of some combination 
of behavioral responses, autonomic nervous system responses, 
neuroendocrine responses, or immune responses (e.g., Seyle 1950; Moberg 
2000). In many cases, an animal's first and sometimes most economical 
(in terms of energetic costs) response is behavioral avoidance of the 
potential stressor. Autonomic nervous system responses to stress 
typically involve changes in heart rate, blood pressure, and 
gastrointestinal activity. These responses have a relatively short 
duration and may or may not have a significant long-term effect on an 
animal's fitness.
    Neuroendocrine stress responses often involve the hypothalamus-
pituitary-adrenal system. Virtually all neuroendocrine functions that 
are affected by stress--including immune competence, reproduction, 
metabolism, and behavior--are regulated by pituitary hormones. Stress-
induced changes in the secretion of pituitary hormones have been 
implicated in failed reproduction, altered metabolism, reduced immune 
competence, and behavioral disturbance (e.g., Moberg, 1987; Blecha, 
2000). Increases in the circulation of glucocorticoids are also equated 
with stress (Romano et al. 2004).
    The primary distinction between stress (which is adaptive and does 
not normally place an animal at risk) and ``distress'' is the cost of 
the response. During a stress response, an animal uses glycogen stores 
that can be quickly replenished once the stress is alleviated. In such 
circumstances, the cost of the stress response would not pose serious 
fitness consequences. However, when an animal does not have sufficient 
energy reserves to satisfy the energetic costs of a stress response, 
energy resources must be diverted from other functions. This state of 
distress will last until the animal replenishes its energetic reserves 
sufficient to restore normal function.
    Relationships between these physiological mechanisms, animal 
behavior, and the costs of stress responses are well-studied through 
controlled experiments and for both laboratory and free-ranging animals 
(e.g., Holberton et al. 1996; Hood et al. 1998; Jessop et al. 2003; 
Krausman et al. 2004; Lankford et al. 2005). Stress responses due to 
exposure to anthropogenic sounds or other stressors and their effects 
on marine mammals have also been reviewed (Fair and Becker, 2000; 
Romano et al. 2002b) and, more rarely, studied in wild populations 
(e.g., Romano et al. 2002a). These and other studies lead to a 
reasonable expectation that some marine mammals will experience 
physiological stress responses upon exposure to acoustic stressors and 
that it is possible that some of these would be classified as 
``distress.'' In addition, any animal experiencing TTS would likely 
also experience stress responses (NRC, 2003).
    Auditory masking--Sound can disrupt behavior through masking, or 
interfering with, an animal's ability to detect, recognize, or 
discriminate between acoustic signals of interest (e.g., those used for 
intraspecific communication and social interactions, prey detection, 
predator avoidance, navigation) (Richardson et al. 1995). Masking 
occurs when the receipt of a sound is interfered with by another 
coincident sound at similar frequencies and at similar or higher 
intensity, and may occur whether the sound is natural (e.g., snapping 
shrimp, wind, waves, precipitation) or anthropogenic (e.g., shipping, 
sonar, seismic exploration) in origin. The ability of a noise source to 
mask biologically important sounds depends on the characteristics of 
both the noise source and the signal of interest (e.g., signal-to-noise 
ratio, temporal variability, direction), in relation to each other and 
to an animal's hearing abilities (e.g., sensitivity, frequency range, 
critical ratios, frequency discrimination, directional discrimination, 
age or TTS hearing loss), and existing ambient noise and propagation 
conditions.
    Under certain circumstances, marine mammals experiencing 
significant masking could also be impaired from maximizing their 
performance fitness in survival and reproduction. Therefore, when the 
coincident (masking) sound is anthropogenic, it may be considered 
harassment when disrupting or altering critical behaviors. It is 
important to distinguish TTS and PTS, which persist after the sound 
exposure, from masking, which occurs during the sound exposure. Because 
masking (without resulting in TS) is not associated with abnormal 
physiological function, it is not considered a physiological effect, 
but rather a potential behavioral effect.
    The frequency range of the potentially masking sound is important 
in determining any potential behavioral impacts. For example, low-
frequency signals may have less effect on high-frequency echolocation 
sounds produced by odontocetes but are more likely to affect detection 
of mysticete communication calls and other potentially important 
natural sounds such as those produced by surf and some prey species. 
The masking of communication signals by anthropogenic noise may be 
considered as a reduction in the communication space of animals (e.g., 
Clark et al. 2009) and may result in energetic or other costs as 
animals change their vocalization behavior (e.g., Miller et al. 2000; 
Foote et al. 2004; Parks et al. 2007b; Di Iorio and Clark, 2009; Holt 
et al. 2009). Masking can be reduced in

[[Page 70464]]

situations where the signal and noise come from different directions 
(Richardson et al. 1995), through amplitude modulation of the signal, 
or through other compensatory behaviors (Houser and Moore, 2014). 
Masking can be tested directly in captive species (e.g., Erbe 2008), 
but in wild populations it must be either modeled or inferred from 
evidence of masking compensation. There are few studies addressing 
real-world masking sounds likely to be experienced by marine mammals in 
the wild (e.g., Branstetter et al. 2013).
    Masking affects both senders and receivers of acoustic signals and 
can potentially have long-term chronic effects on marine mammals at the 
population level as well as at the individual level. Low-frequency 
ambient sound levels have increased by as much as 20 dB (more than 
three times in terms of SPL) in the world's ocean from pre-industrial 
periods, with most of the increase from distant commercial shipping 
(Hildebrand 2009). All anthropogenic sound sources, but especially 
chronic and lower-frequency signals (e.g., from vessel traffic), 
contribute to elevated ambient sound levels, thus intensifying masking.
    Potential Effects of Sonar on Prey--Ringed seals feed on marine 
invertebrates and fish. Marine invertebrates occur in the world's 
oceans, from warm shallow waters to cold deep waters, and are the 
dominant animals in all habitats of the ICEX22 Study Area. Although 
most species are found within the benthic zone, marine invertebrates 
can be found in all zones (sympagic (within the sea ice), pelagic (open 
ocean), or benthic (bottom dwelling)) of the Beaufort Sea (Josefson et 
al. 2013). The diverse range of species include oysters, crabs, worms, 
ghost shrimp, snails, sponges, sea fans, isopods, and stony corals 
(Chess and Hobson 1997; Dugan et al. 2000; Proctor et al. 1980).
    Hearing capabilities of invertebrates are largely unknown (Lovell 
et al. 2005; Popper and Schilt 2008). Outside of studies conducted to 
test the sensitivity of invertebrates to vibrations, very little is 
known on the effects of anthropogenic underwater noise on invertebrates 
(Edmonds et al. 2016). While data are limited, research suggests that 
some of the major cephalopods and decapods may have limited hearing 
capabilities (Hanlon 1987; Offutt 1970), and may hear only low-
frequency (less than 1 kHz) sources (Offutt 1970), which is most likely 
within the frequency band of biological signals (Hill 2009). In a 
review of crustacean sensitivity of high amplitude underwater noise by 
Edmonds et al. (2016), crustaceans may be able to hear the frequencies 
at which they produce sound, but it remains unclear which noises are 
incidentally produced and if there are any negative effects from 
masking them. Acoustic signals produced by crustaceans range from low 
frequency rumbles (20-60 Hz) to high frequency signals (20-55 kHz) 
(Henninger and Watson 2005; Patek and Caldwell 2006; Staaterman et al. 
2016). Aquatic invertebrates that can sense local water movements with 
ciliated cells include cnidarians, flatworms, segmented worms, 
urochordates (tunicates), mollusks, and arthropods (Budelmann 1992a, 
1992b; Popper et al. 2001). Some aquatic invertebrates have specialized 
organs called statocysts for determination of equilibrium and, in some 
cases, linear or angular acceleration. Statocysts allow an animal to 
sense movement and may enable some species, such as cephalopods and 
crustaceans, to be sensitive to water particle movements associated 
with sound (Goodall et al. 1990; Hu et al. 2009; Kaifu et al. 2008; 
Montgomery et al. 2006; Popper et al. 2001; Roberts and Breithaupt 
2016; Salmon 1971). Because any acoustic sensory capabilities, if 
present at all, are limited to detecting water motion, and water 
particle motion near a sound source falls off rapidly with distance, 
aquatic invertebrates are probably limited to detecting nearby sound 
sources rather than sound caused by pressure waves from distant 
sources.
    Studies of sound energy effects on invertebrates are few, and 
identify only behavioral responses. Non-auditory injury, PTS, TTS, and 
masking studies have not been conducted for invertebrates. Both 
behavioral and auditory brainstem response studies suggest that 
crustaceans may sense frequencies up to 3 kHz, but best sensitivity is 
likely below 200 Hz (Goodall et al. 1990; Lovell et al. 2005; Lovell et 
al. 2006). Most cephalopods likely sense low-frequency sound below 1 
kHz, with best sensitivities at lower frequencies (Budelmann 2010; 
Mooney et al. 2010; Offutt 1970). A few cephalopods may sense higher 
frequencies up to 1,500 Hz (Hu et al. 2009).
    It is expected that most marine invertebrates would not sense the 
frequencies of the sonar associated with the proposed specified 
activities. Most marine invertebrates would not be close enough to 
active sonar systems to potentially experience impacts to sensory 
structures. Any marine invertebrate capable of sensing sound may alter 
its behavior if exposed to sonar. Although acoustic transmissions 
produced during the proposed specified activities may briefly impact 
individuals, intermittent exposures to sonar are not expected to impact 
survival, growth, recruitment, or reproduction of widespread marine 
invertebrate populations.
    The fish species located in the ICEX22 Study Area include those 
that are closely associated with the deep ocean habitat of the Beaufort 
Sea. Nearly 250 marine fish species have been described in the Arctic, 
excluding the larger parts of the sub-Arctic Bering, Barents, and 
Norwegian Seas (Mecklenburg et al. 2011). However, only about 30 are 
known to occur in the Arctic waters of the Beaufort Sea (Christiansen 
and Reist 2013). Largely because of the difficulty of sampling in 
remote, ice-covered seas, many high-Arctic fish species are known only 
from rare or geographically patchy records (Mecklenburg et al. 2011). 
Aquatic systems of the Arctic undergo extended seasonal periods of ice 
cover and other harsh environmental conditions. Fish inhabiting such 
systems must be biologically and ecologically adapted to surviving such 
conditions. Important environmental factors that Arctic fish must 
contend with include reduced light, seasonal darkness, ice cover, low 
biodiversity, and low seasonal productivity.
    All fish have two sensory systems to detect sound in the water: The 
inner ear, which functions very much like the inner ear in other 
vertebrates, and the lateral line, which consists of a series of 
receptors along the fish's body (Popper and Fay 2010; Popper et al. 
2014). The inner ear generally detects relatively higher-frequency 
sounds, while the lateral line detects water motion at low frequencies 
(below a few hundred Hz) (Hastings and Popper 2005). Lateral line 
receptors respond to the relative motion between the body surface and 
surrounding water; this relative motion, however, only takes place very 
close to sound sources and most fish are unable to detect this motion 
at more than one to two body lengths distance away (Popper et al. 
2014). Although hearing capability data only exist for fewer than 100 
of the approximately 32,000 fish species known to exist, current data 
suggest that most species of fish detect sounds from 50 to 1,000 Hz, 
with few fish hearing sounds above 4 kHz (Popper 2008). It is believed 
that most fish have their best hearing sensitivity from 100 to 400 Hz 
(Popper 2003). Permanent hearing loss has not been documented in fish. 
A study by Halvorsen et al. (2012) found that for temporary hearing 
loss or similar negative impacts to occur, the noise needed to be 
within the fish's individual hearing frequency range;

[[Page 70465]]

external factors, such as developmental history of the fish or 
environmental factors, may result in differing impacts to sound 
exposure in fish of the same species. The sensory hair cells of the 
inner ear in fish can regenerate after they are damaged, unlike in 
mammals where sensory hair cells loss is permanent (Lombarte et al. 
1993; Smith et al. 2006). As a consequence, any hearing loss in fish 
may be as temporary as the timeframe required to repair or replace the 
sensory cells that were damaged or destroyed (Smith et al. 2006), and 
no permanent loss of hearing in fish would result from exposure to 
sound.
    Fish species in the ICEX22 Study Area are expected to hear the low-
frequency sources associated with the proposed specified activities, 
but most are not expected to detect the higher-frequency sounds. Only a 
few fish species are able to detect mid-frequency sonar above 1 kHz and 
could have behavioral reactions or experience auditory masking during 
these activities. These effects are expected to be transient, and long-
term consequences for the population are not expected. Fish with 
hearing specializations capable of detecting high-frequency sounds are 
not expected to be within the ICEX22 Study Area. If hearing specialists 
were present, they would have to be in close vicinity to the source to 
experience effects from the acoustic transmission. Human-generated 
sound could alter the behavior of a fish in a manner that would affect 
its way of living, such as where it tries to locate food or how well it 
can locate a potential mate; behavioral responses to loud noise could 
include a startle response, such as the fish swimming away from the 
source, the fish ``freezing'' and staying in place, or scattering 
(Popper 2003). Auditory masking could also interfere with a fish's 
ability to hear biologically relevant sounds, inhibiting the ability to 
detect both predators and prey, and impacting schooling, mating, and 
navigating (Popper 2003). If an individual fish comes into contact with 
low-frequency acoustic transmissions and is able to perceive the 
transmissions, they are expected to exhibit short-term behavioral 
reactions, when initially exposed to acoustic transmissions, which 
would not significantly alter breeding, foraging, or populations. 
Overall effects to fish from ICEX22 active sonar sources would be 
localized, temporary, and infrequent.
    Potential Effects of Vessel Strike--Because ICEX22 would occur only 
when there is ice coverage and conditions are appropriate to establish 
an ice camp on an ice floe, no ships or smaller boats would be involved 
in the activity. Vessel use would be limited to submarines and unmanned 
underwater vehicles (hereafter referred to together as ``vessels'' 
unless noted separately). The potential for vessel strike during ICEX22 
would therefore only arise from the use of submarines during training 
and testing activities, and the use of unmanned underwater vehicles 
during research activities. Depths at which vessels would operate 
during ICEX22 would overlap with known dive depths of ringed seals, 
which have been recorded to 300 m in depth (Gjertz et al. 2000; 
Lydersen 1991). Few authors have specifically described the responses 
of pinnipeds to vessels, and most of the available information on 
reactions to boats concerns pinnipeds hauled out on land or ice. No 
information is available on potential responses to submarines or 
unmanned underwater vehicles. Brueggeman et al. (1992) stated ringed 
seals hauled out on the ice showed short-term escape reactions when 
they were within 0.25-0.5 km from a vessel; ringed seals would likely 
show similar reactions to submarines and unmanned underwater vehicles, 
decreasing the likelihood of vessel strike during ICEX22 activities.
    Dating back more than 20 years and for as long as it has kept 
records, the Navy has no records of individual pinnipeds being struck 
by a vessel as a result of Navy activities and, further, the smaller 
size and maneuverability of pinnipeds make a vessel strike unlikely. 
Also, NMFS has never received any reports indicating that pinnipeds 
have been struck by vessels of any type. Review of additional sources 
of information in the form of worldwide ship strike records shows 
little evidence of strikes of pinnipeds from the shipping sector. 
Further, a review of seal stranding data from Alaska found that during 
2020, 9 ringed seal strandings were recorded by the Alaska Marine 
Mammal Stranding Network. Within the Arctic region of Alaska, 7 ringed 
seal strandings were recorded. Of the 9 strandings reported in Alaska 
(all regions included), none were found to be caused by vessel 
collisions (Savage 2021).
    Vessel speed, size, and mass are all important factors in 
determining both the potential likelihood and impacts of a vessel 
strike to marine mammals (Conn and Silber, 2013; Gende et al. 2011; 
Silber et al. 2010; Vanderlaan and Taggart, 2007; Wiley et al. 2016). 
When submerged, submarines are generally slow moving (to avoid 
detection) and therefore marine mammals at depth with a submarine are 
likely able to avoid collision with the submarine. For most of the 
research and training and testing activities during the specified 
activity, submarine and unmanned underwater vehicle speeds would not 
typically exceed 10 knots during the time spent within the ICEX22 Study 
Area, which would lessen the already extremely unlikely chance of 
collisions with marine mammals, specifically ringed seals.
    Based on consideration of all this information, NMFS does not 
anticipate incidental take of marine mammals by vessel strike from 
submarines or unmanned underwater vehicles.
    Potential Effects of Exercise Weapon Strike--As noted in the 
Detailed Description of Specific Activity section, the Navy may use up 
to 20 inert exercise weapons in ICEX22. While the details of the 
proposed exercise weapon exercises are classified, given the limited 
potential number of exercise weapons deployed during the exercise 
window, and the low density of ringed seals in the project area during 
this time, NMFS does not anticipate incidental take of marine mammals 
by exercise weapon strike.
    Effects of Acoustics on Physical and Foraging Habitat--Unless the 
sound source is stationary and/or continuous over a long duration in 
one area, neither of which applies to ICEX22 activities, the effects of 
the introduction of sound into the environment are generally considered 
to have a less severe impact on marine mammal habitat compared to any 
physical alteration of the habitat. Acoustic exposures are not expected 
to result in long-term physical alteration of the water column or 
bottom topography as the occurrences are of limited duration and would 
occur intermittently. Acoustic transmissions also would have no 
structural impact to subnivean lairs in the ice. Furthermore, since ice 
dampens acoustic transmissions (Richardson et al. 1995) the level of 
sound energy that reaches the interior of a subnivean lair would be 
less than that ensonifying water under surrounding ice. For these 
reasons, it is unlikely that the Navy's acoustic activities in the 
ICEX22 Study Area would have any effect on marine mammal habitat, 
including habitat that was considered for designation as ESA critical 
habitat in the current ESA rulemaking process.
    Non-acoustic Impacts--Deployment of the ice camp could potentially 
affect ringed seal habitat by physically damaging or crushing subnivean 
lairs, which could potentially result in ringed seal injury or 
mortality. March 1 is generally expected to be the onset of ice seal 
lairing season, and ringed seals

[[Page 70466]]

typically construct lairs near pressure ridges. As described in the 
Proposed Mitigation section, the ice camp and runway would be 
established on a combination of first-year ice and multi-year ice 
without pressure ridges, which would minimize the possibility of 
physical impacts to subnivean lairs and habitat suitable for lairs. Ice 
camp deployment would begin mid-February, and be gradual, with activity 
increasing over the first five days. So in addition, this schedule 
would discourage seals from establishing birthing lairs in or near the 
ice camp, and would allow ringed seals to relocate outside of the ice 
camp area as needed, though both scenarios are unlikely as described 
below in this section. Personnel on on-ice vehicles would observe for 
marine mammals, and would follow established routes when available, to 
avoid potential disturbance of lairs and habitat suitable for lairs. 
Personnel on foot and operating on-ice vehicles would avoid deep snow 
drifts near pressure ridges, also to avoid potential lairs and habitat 
suitable for lairs. Implementation of these measures are expected to 
prevent ringed seal lairs from being crushed or damaged during ICEX22 
activities, and are expected to minimize any other potential impacts to 
sea ice habitat suitable for the formation of lairs. Given the proposed 
mitigation requirements, we also do not anticipate ringed seal injury 
or mortality as a result of damage to subnivean lairs.
    ICEX22 personnel would be actively conducting testing and training 
operations on the sea ice and would travel around the camp area, 
including the runway, on snowmobiles. Although the Navy does not 
anticipate observing any seals on the ice given the lack of 
observations during previous ice exercises (U.S. Navy, 2020), it is 
possible that the presence of active humans could behaviorally disturb 
ringed seals that are in lairs or on the ice. For example, if a seal is 
present and would have otherwise built a lair in the area of the ice 
camp, it could be displaced, or a seal may choose to relocate to a 
different, existing lair outside of the ice camp area. Displacement of 
seal lair construction or relocation to existing lairs outside of the 
ice camp area is unlikely, given the low average density of structures 
(the average ringed seal ice structure density in the vicinity of 
Prudhoe Bay, Alaska is 1.58 structures per km\2\ (Table 3)), the lack 
of previous ringed seal observations on the ice during ICEX activities, 
and proposed mitigation requirements that would require the Navy to 
construct the ice camp and runway on first-year or multiyear ice 
without pressure ridges and would require personnel to avoid areas of 
deep snow drift or pressure ridges.

              Table 3--Ringed Seal Ice Structure Density in the Vicinity of the Prudhoe Bay, Alaska
----------------------------------------------------------------------------------------------------------------
                                             Ice structure density
                   Year                      (structures per km\2\)                     Source
----------------------------------------------------------------------------------------------------------------
1982......................................                      3.6  Frost and Burns 1989.
1983......................................                     0.81  Kelly et al. 1986.
1999......................................                     0.71  Williams et al. 2001.
2000......................................                      1.2  Williams et al. 2001.
Average Density...........................                     1.58
----------------------------------------------------------------------------------------------------------------

    Given the required mitigation measures and the low density of 
ringed seals anticipated in the Ice Camp Study Area during ICEX22, we 
do not anticipate behavioral disturbance of ringed seals due to human 
presence.
    The Navy's activities would occur prior to the late spring to early 
summer ``basking period,'' which occurs between abandonment of the 
subnivean lairs and melting of the seasonal sea ice, and is when the 
seals undergo their annual molt (Kelly et al. 2010b). Given that the 
ice camp would be demobilized prior to the basking period, and the 
remainder of the Navy's activities occur below the sea ice, impacts to 
sea ice habitat suitable as a platform for basking and molting are not 
anticipated to result from the Navy's ICEX22 activities.
    Our preliminary determination of potential effects to the physical 
environment includes minimal possible impacts to marine mammals and 
their habitat from camp operation or deployment activities, given the 
proposed mitigation and the timing of the Navy's proposed activities. 
In addition, given the relatively short duration of submarine testing 
and training activities, the relatively small area that would be 
affected, and the lack of impacts to physical or foraging habitat, the 
proposed specified activities are not likely to have an adverse effect 
on prey species or marine mammal habitat, other than potential 
localized, temporary, and infrequent effects to fish as discussed 
above. Therefore, any impacts to ringed seals and their habitat, as 
discussed above in this section, are not expected to cause significant 
or long-term consequences for individual ringed seals or the 
population. Please see the Negligible Impact Analysis and Determination 
section for additional discussion regarding the likely impacts of the 
Navy's activities on ringed seals, including the reproductive success 
or survivorship of individual ringed seals, and how those impacts on 
individuals are likely to impact the species or stock.

Estimated Take

    This section provides an estimate of the number of incidental takes 
proposed for authorization through this IHA, which will inform NMFS' 
analysis for the negligible impact determination.
    Harassment is the only type of take expected to result from these 
activities. For this military readiness activity, the MMPA defines 
``harassment'' as (i) Any act that injures or has the significant 
potential to injure a marine mammal or marine mammal stock in the wild 
(Level A harassment); or (ii) Any act that disturbs or is likely to 
disturb a marine mammal or marine mammal stock in the wild by causing 
disruption of natural behavioral patterns, including, but not limited 
to, migration, surfacing, nursing, breeding, feeding, or sheltering, to 
a point where the behavioral patterns are abandoned or significantly 
altered (Level B harassment).
    Authorized takes for the Navy's ICEX22 activities would be by Level 
B harassment only, in the form of disruption of behavioral patterns 
and/or TTS for individual marine mammals resulting from exposure to 
acoustic transmissions. Based on the nature of the activity, Level A 
harassment is neither anticipated nor proposed to be authorized. As 
described previously, no mortality or serious injury is anticipated or 
proposed to be authorized for this activity. Below we describe how the 
incidental take is estimated.
    Generally speaking, we estimate take by considering: (1) Acoustic 
thresholds above which NMFS believes the best available science 
indicates marine mammals will be behaviorally disturbed or incur some 
degree of permanent

[[Page 70467]]

hearing impairment; (2) the area or volume of water that will be 
ensonified above these levels in a day; (3) the density or occurrence 
of marine mammals within these ensonified areas; and (4) the number of 
days of activities. For this proposed IHA, the Navy employed a 
sophisticated model known as the Navy Acoustic Effects Model (NAEMO) to 
assess the estimated impacts of underwater sound.

Acoustic Thresholds

    NMFS recommends the use of acoustic thresholds that identify the 
received level of underwater sound above which exposed marine mammals 
would be reasonably expected to be behaviorally disturbed (equated to 
Level B harassment) or to incur PTS of some degree (equated to Level A 
harassment).
    Level B Harassment by behavioral disturbance for non-explosive 
sources--In coordination with NMFS, the Navy developed behavioral 
thresholds to support environmental analyses for the Navy's testing and 
training military readiness activities utilizing active sonar sources; 
these behavioral harassment thresholds are used here to evaluate the 
potential effects of the active sonar components of the proposed 
specified activities. The behavioral response of a marine mammal to an 
anthropogenic sound will depend on the frequency, duration, temporal 
pattern, and amplitude of the sound as well as the animal's prior 
experience with the sound and the context in which the sound is 
encountered (i.e., what the animal is doing at the time of the 
exposure). The distance from the sound source and whether it is 
perceived as approaching or moving away can also affect the way an 
animal responds to a sound (Wartzok et al. 2003). For marine mammals, a 
review of responses to anthropogenic sound was first conducted by 
Richardson et al. (1995). Reviews by Nowacek et al. (2007) and Southall 
et al. (2007) address studies conducted since 1995 and focus on 
observations where the received sound level of the exposed marine 
mammal(s) was known or could be estimated.
    Multi-year research efforts have conducted sonar exposure studies 
for odontocetes and mysticetes (Miller et al. 2012; Sivle et al. 2012). 
Several studies with captive animals have provided data under 
controlled circumstances for odontocetes and pinnipeds (Houser et al. 
2013a; Houser et al. 2013b). Moretti et al. (2014) published a beaked 
whale dose-response curve based on PAM of beaked whales during Navy 
training activity at Atlantic Underwater Test and Evaluation Center 
during actual Anti-Submarine Warfare exercises. This new information 
necessitated the update of the behavioral response criteria for the 
Navy's environmental analyses.
    Southall et al. (2007) synthesized data from many past behavioral 
studies and observations to determine the likelihood of behavioral 
reactions at specific sound levels. While in general, the louder the 
sound source the more intense the behavioral response, it was clear 
that the proximity of a sound source and the animal's experience, 
motivation, and conditioning were also critical factors influencing the 
response (Southall et al. 2007). After examining all of the available 
data, the authors felt that the derivation of thresholds for behavioral 
response based solely on exposure level was not supported because 
context of the animal at the time of sound exposure was an important 
factor in estimating response. Nonetheless, in some conditions, 
consistent avoidance reactions were noted at higher sound levels 
depending on the marine mammal species or group, allowing conclusions 
to be drawn. Phocid seals showed avoidance reactions at or below 190 dB 
re 1 [mu]Pa at 1 m; thus, seals may actually receive levels adequate to 
produce TTS before avoiding the source.
    The Navy's Phase III proposed pinniped behavioral threshold was 
updated based on controlled exposure experiments on the following 
captive animals: Hooded seal, gray seal, and California sea lion 
(G[ouml]tz et al. 2010; Houser et al. 2013a; Kvadsheim et al. 2010). 
Overall exposure levels were 110-170 dB re 1 [mu]Pa for hooded seals, 
140-180 dB re 1 [mu]Pa for gray seals, and 125-185 dB re 1 [mu]Pa for 
California sea lions; responses occurred at received levels ranging 
from 125 to 185 dB re 1 [mu]Pa. However, the means of the response data 
were between 159 and 170 dB re 1 [mu]Pa. Hooded seals were exposed to 
increasing levels of sonar until an avoidance response was observed, 
while the grey seals were exposed first to a single received level 
multiple times, then an increasing received level. Each individual 
California sea lion was exposed to the same received level ten times. 
These exposure sessions were combined into a single response value, 
with an overall response assumed if an animal responded in any single 
session. Because these data represent a dose-response type relationship 
between received level and a response, and because the means were all 
tightly clustered, the Bayesian biphasic Behavioral Response Function 
for pinnipeds most closely resembles a traditional sigmoidal dose-
response function at the upper received levels and has a 50 percent 
probability of response at 166 dB re 1 [mu]Pa. Additionally, to account 
for proximity to the source discussed above and based on the best 
scientific information, a conservative distance of 10 km is used beyond 
which exposures would not constitute a take under the military 
readiness definition of Level B harassment. The Navy proposed, and NMFS 
concurs with, the use of this dose response function to predict 
behavioral harassment of pinnipeds for this activity.
    Level A harassment and Level B harassment by threshold shift for 
non-explosive sources--NMFS' Technical Guidance for Assessing the 
Effects of Anthropogenic Sound on Marine Mammal Hearing (Version 2.0; 
Technical Guidance, 2018) identifies dual criteria to assess auditory 
injury (Level A harassment) to five different marine mammal groups 
(based on hearing sensitivity) as a result of exposure to noise from 
two different types of sources (impulsive or non-impulsive).
    These thresholds were developed by compiling the best available 
science and soliciting input multiple times from both the public and 
peer reviewers to inform the final product. The references, analysis, 
and methodology used in the development of the thresholds are described 
in NMFS 2018 Technical Guidance, which may be accessed at https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-acoustic-technical-guidance.
    The Navy's PTS/TTS analysis begins with mathematical modeling to 
predict the sound transmission patterns from Navy sources, including 
sonar. These data are then coupled with marine species distribution and 
abundance data to determine the sound levels likely to be received by 
various marine species. These criteria and thresholds are applied to 
estimate specific effects that animals exposed to Navy-generated sound 
may experience. For weighting function derivation, the most critical 
data required are TTS onset exposure levels as a function of exposure 
frequency. These values can be estimated from published literature by 
examining TTS as a function of sound exposure level (SEL) for various 
frequencies.
    To estimate TTS onset values, only TTS data from behavioral hearing 
tests were used. To determine TTS onset for each subject, the amount of 
TTS observed after exposures with different SPLs and durations were 
combined to create a single TTS growth curve as a function of SEL. The 
use of (cumulative)

[[Page 70468]]

SEL is a simplifying assumption to accommodate sounds of various SPLs, 
durations, and duty cycles. This is referred to as an ``equal energy'' 
approach, since SEL is related to the energy of the sound and this 
approach assumes exposures with equal SEL result in equal effects, 
regardless of the duration or duty cycle of the sound. It is well known 
that the equal energy rule will over-estimate the effects of 
intermittent noise, since the quiet periods between noise exposures 
will allow some recovery of hearing compared to noise that is 
continuously present with the same total SEL (Ward 1997). For 
continuous exposures with the same SEL but different durations, the 
exposure with the longer duration will also tend to produce more TTS 
(Finneran et al. 2010; Kastak et al. 2007; Mooney et al. 2009a).
    As in previous acoustic effects analysis (Finneran and Jenkins 
2012; Southall et al. 2007), the shape of the PTS exposure function for 
each species group is assumed to be identical to the TTS exposure 
function for each group. A difference of 20 dB between TTS onset and 
PTS onset is used for all marine mammals including pinnipeds. This is 
based on estimates of exposure levels actually required for PTS (i.e., 
40 dB of TTS) from the marine mammal TTS growth curves, which show 
differences of 13 to 37 dB between TTS and PTS onset in marine mammals. 
Details regarding these criteria and thresholds can be found in NMFS' 
Technical Guidance (NMFS 2018).
    Table 4 below provides the weighted criteria and thresholds used in 
this analysis for estimating quantitative acoustic exposures of marine 
mammals from the proposed specified activities.

  Table 4--Acoustic Thresholds Identifying the Onset of Behavioral Disturbance, TTS, and PTS for Non-Impulsive
                                                Sound Sources \1\
----------------------------------------------------------------------------------------------------------------
                                                                                   Physiological criteria
                                                            Behavioral     -------------------------------------
    Functional hearing group            Species              criteria       TTS threshold SEL  PTS threshold SEL
                                                                                (weighted)         (weighted)
----------------------------------------------------------------------------------------------------------------
Phocid Pinnipeds (Underwater)..  Ringed seal..........  Pinniped Dose       181 dB SEL         201 dB SEL
                                                         Response Function   cumulative.        cumulative.
                                                         \2\.
----------------------------------------------------------------------------------------------------------------
\1\ The threshold values provided are assumed for when the source is within the animal's best hearing
  sensitivity. The exact threshold varies based on the overlap of the source and the frequency weighting.
\2\ See Figure 6-1 in the Navy's IHA application.
Note: SEL thresholds in dB re: 1 [mu]Pa\2\ s.

Quantitative Modeling

    The Navy performed a quantitative analysis to estimate the number 
of marine mammals that could be harassed by the underwater acoustic 
transmissions during the proposed specified activities. Inputs to the 
quantitative analysis included marine mammal density estimates, marine 
mammal depth occurrence distributions (U.S. Department of the Navy, 
2017), oceanographic and environmental data, marine mammal hearing 
data, and criteria and thresholds for levels of potential effects.
    The density estimate used to estimate take is derived from habitat-
based modeling by Kaschner et al. (2006) and Kaschner (2004). The area 
of the Arctic where the proposed specified activities would occur (100-
200 nmi north of Prudhoe Bay, Alaska) has not been surveyed in a manner 
that supports quantifiable density estimation of marine mammals. In the 
absence of empirical survey data, information on known or inferred 
associations between marine habitat features and (the likelihood of) 
the presence of specific species have been used to predict densities 
using model-based approaches. These habitat suitability models include 
relative environmental suitability (RES) models. Habitat suitability 
models can be used to understand the possible extent and relative 
expected concentration of a marine species distribution. These models 
are derived from an assessment of the species occurrence in association 
with evaluated environmental explanatory variables that results in 
defining the RES suitability of a given environment. A fitted model 
that quantitatively describes the relationship of occurrence with the 
environmental variables can be used to estimate unknown occurrence in 
conjunction with known habitat suitability. Abundance can thus be 
estimated for each RES value based on the values of the environmental 
variables, providing a means to estimate density for areas that have 
not been surveyed. Use of the Kaschner's RES model resulted in a value 
of 0.3957 ringed seals per km\2\ in the cold season (defined as 
December through May).
    The quantitative analysis consists of computer modeled estimates 
and a post-model analysis to determine the number of potential animal 
exposures. The model calculates sound energy propagation from the 
proposed sonars, the sound received by animat (virtual animal) 
dosimeters representing marine mammals distributed in the area around 
the modeled activity, and whether the sound received by a marine mammal 
exceeds the thresholds for effects.
    The Navy developed a set of software tools and compiled data for 
estimating acoustic effects on marine mammals without consideration of 
behavioral avoidance or Navy's standard mitigations (Lookouts, safety 
zones, avoidance zones, etc.). These tools and data sets are integral 
components of NAEMO. In NAEMO, animats are distributed non-uniformly 
based on species-specific density, depth distribution, and group size 
information, and animats record energy received at their location in 
the water column. A fully three-dimensional environment is used for 
calculating sound propagation and animat exposure in NAEMO. Site-
specific bathymetry, sound speed profiles, wind speed, and bottom 
properties are incorporated into the propagation modeling process. 
NAEMO calculates the likely propagation for various levels of energy 
(sound or pressure) resulting from each source used during the training 
or testing event.
    NAEMO then records the energy received by each animat within the 
energy footprint of the event and calculates the number of animats 
having received levels of energy exposures that fall within defined 
impact thresholds. Predicted effects on the animats within a scenario 
are then tallied and the highest order effect (based on severity of 
criteria; e.g., PTS over TTS) predicted for a given animat is assumed. 
Each scenario or each 24-hour period for scenarios lasting greater than 
24 hours is independent of all others, and therefore, the same 
individual marine animal could be impacted during each independent 
scenario or 24-hour period. In a few instances for the modeling of the 
specified activities here, although the activities themselves all occur 
within the ICEX22 Study Area, sound may propagate beyond the boundary 
of the ICEX22 Study Area. Any exposures occurring outside the boundary 
of the

[[Page 70469]]

study area are counted as if they occurred within the ICEX22 Study Area 
boundary. NAEMO provides the initial estimated impacts on marine 
species with a static horizontal distribution.
    There are limitations to the data used in the acoustic effects 
model, and the results must be interpreted within this context. While 
the most accurate data and input assumptions have been used in the 
modeling, when there is a lack of definitive data to support an aspect 
of the modeling, modeling assumptions believed to overestimate the 
number of exposures have been chosen:
     Animats are modeled as being underwater, stationary, and 
facing the source and therefore always predicted to receive the maximum 
sound level (i.e., no porpoising or pinnipeds' heads above water);
     Animats do not move horizontally (but do change their 
position vertically within the water column), which may overestimate 
physiological effects such as hearing loss, especially for slow moving 
or stationary sound sources in the model;
     Animats are stationary horizontally and therefore do not 
avoid the sound source, unlike in the wild where animals would most 
often avoid exposures at higher sound levels, especially those 
exposures that may result in PTS;
     Multiple exposures within any 24-hour period are 
considered one continuous exposure for the purposes of calculating the 
temporary or permanent hearing loss, because there are not sufficient 
data to estimate a hearing recovery function for the time between 
exposures; and
     Mitigation measures that would be implemented were not 
considered in the model. In reality, sound-producing activities would 
be reduced, stopped, or delayed if marine mammals are detected by 
submarines via PAM.
    Because of these inherent model limitations and simplifications, 
model-estimated results must be further analyzed, considering such 
factors as the range to specific effects, avoidance, and typically the 
likelihood of successfully implementing mitigation measures. This 
analysis uses a number of factors in addition to the acoustic model 
results to predict effects on marine mammals.
    For non-impulsive sources, NAEMO calculates the sound pressure 
level (SPL) and sound exposure level (SEL) for each active emission 
during an event. This is done by taking the following factors into 
account over the propagation paths: Bathymetric relief and bottom 
types, sound speed, and attenuation contributors such as absorption, 
bottom loss, and surface loss. Platforms such as a ship using one or 
more sound sources are modeled in accordance with relevant vehicle 
dynamics and time durations by moving them across an area whose size is 
representative of the training event's operational area. Table 5 
provides range to effects for active acoustic sources proposed for 
ICEX22 to phocid pinniped-specific criteria. Phocids within these 
ranges would be predicted to receive the associated effect. Range to 
effects is important information in not only predicting acoustic 
impacts, but also in verifying the accuracy of model results against 
real-world situations and determining adequate mitigation ranges to 
avoid higher level effects, especially physiological effects, to marine 
mammals.

                 Table 5--Range to Behavioral Disturbance, TTS, and PTS in the ICEX22 Study Area
----------------------------------------------------------------------------------------------------------------
                                                                              Range to effects (m)
                                                              --------------------------------------------------
                       Source/exercise                            Behavioral
                                                                 disturbance          TTS              PTS
----------------------------------------------------------------------------------------------------------------
Submarine Exercise...........................................      \a\ 10,000            3,025              130
----------------------------------------------------------------------------------------------------------------
\a\ Empirical evidence has not shown responses to sonar that would constitute take beyond a few km from an
  acoustic source, which is why NMFS and the Navy conservatively set a distance cutoff of 10 km. Regardless of
  the source level at that distance, take is not estimated to occur beyond 10 km from the source.

    As discussed above, within NAEMO, animals do not move horizontally 
or react in any way to avoid sound. Furthermore, mitigation measures 
that are implemented during training or testing activities that reduce 
the likelihood of physiological impacts are not considered in 
quantitative analysis. Therefore, the current model overestimates 
acoustic impacts, especially physiological impacts near the sound 
source. The behavioral criteria used as a part of this analysis 
acknowledges that a behavioral reaction is likely to occur at levels 
below those required to cause hearing loss (TTS or PTS). At close 
ranges and high sound levels approaching those that could cause PTS, 
avoidance of the area immediately around the sound source is the 
assumed behavioral response for most cases.
    In previous environmental analyses, the Navy has implemented 
analytical factors to account for avoidance behavior and the 
implementation of mitigation measures. The application of avoidance and 
mitigation factors has only been applied to model-estimated PTS 
exposures given the short distance over which PTS is estimated. Given 
that no PTS exposures were estimated during the modeling process for 
these proposed specified activities, the implementation of avoidance 
and mitigation factors were not included in this analysis.
    Table 6 shows the exposures expected for ringed seals based on 
NAEMO modeled results.

                Table 6--Quantitative Modeling Results of Potential Exposures for ICEX Activities
----------------------------------------------------------------------------------------------------------------
                                                     Level B harassment
                                             ----------------------------------     Level A
                   Species                       Behavioral                        harassment         Total
                                                disturbance          TTS
----------------------------------------------------------------------------------------------------------------
Ringed seal.................................           3,976              910                0            4,886
----------------------------------------------------------------------------------------------------------------


[[Page 70470]]

    During monitoring for the 2018 IHA covering similar military 
readiness activities in the ICEX22 Study Area, the Navy did not 
visually observe or acoustically detect any marine mammals (U.S. Navy, 
2018). During monitoring for the 2020 IHA covering similar military 
readiness activities in the ICEX22 Study Area, the Navy also did not 
visually observe any marine mammals (U.S. Navy, 2020). Acoustic 
monitoring associated with the 2020 IHA did not detect any discernible 
marine mammal vocalizations (Henderson et al. 2021). The monitoring 
report states that ``there were a few very faint sounds that could have 
been [ringed seal] barks or yelps.'' However, these were likely not 
from ringed seals, given that ringed seal vocalizations are generally 
produced in series (Jones et al. 2014). Henderson et al. (2021) expect 
that these sounds were likely ice-associated or perhaps anthropogenic.

Proposed Mitigation

    In order to issue an IHA under section 101(a)(5)(D) of the MMPA, 
NMFS must set forth the permissible methods of taking pursuant to the 
activity, and other means of effecting the least practicable impact on 
the species or stock and its habitat, paying particular attention to 
rookeries, mating grounds, and areas of similar significance, and on 
the availability of the species or stock for taking for certain 
subsistence uses. NMFS regulations require applicants for incidental 
take authorizations to include information about the availability and 
feasibility (economic and technological) of equipment, methods, and 
manner of conducting the activity or other means of effecting the least 
practicable adverse impact upon the affected species or stocks and 
their habitat (50 CFR 216.104(a)(11)). The 2004 NDAA amended the MMPA 
as it relates to military readiness activities and the incidental take 
authorization process such that ``least practicable impact'' shall 
include consideration of personnel safety, practicality of 
implementation, and impact on the effectiveness of the military 
readiness activity.
    In evaluating how mitigation may or may not be appropriate to 
ensure the least practicable adverse impact on species or stocks and 
their habitat, as well as subsistence uses where applicable, we 
carefully consider two primary factors:
    (1) The manner in which, and the degree to which, the successful 
implementation of the measure(s) is expected to reduce impacts to 
marine mammals, marine mammal species or stocks, and their habitat, as 
well as subsistence uses. This considers the nature of the potential 
adverse impact being mitigated (likelihood, scope, range). It further 
considers the likelihood that the measure will be effective if 
implemented (probability of accomplishing the mitigating result if 
implemented as planned) and the likelihood of effective implementation 
(probability implemented as planned), and;
    (2) The practicability of the measures for applicant 
implementation, which may consider such things as cost, impact on 
operations, and, in the case of a military readiness activity, 
personnel safety, practicality of implementation, and impact on the 
effectiveness of the military readiness activity.

Mitigation for Marine Mammals and Their Habitat

    Appropriate personnel (including civilian personnel) involved in 
mitigation and training or testing activity reporting under the 
specified activities must complete Arctic Environmental and Safety 
Awareness Training. Modules include: Arctic Species Awareness and 
Mitigations, Environmental Considerations, Hazardous Materials 
Management, and General Safety.
    Further, NMFS proposes requiring the following general mitigation 
measures to prevent incidental take of ringed seals on the ice floe 
associated with the ice camp (further explanation of certain mitigation 
measures is provided in parentheses following the measure):
     The ice camp and runway must be established on first-year 
and multi-year ice without pressure ridges. (This will minimize 
physical impacts to subnivean lairs and impacts to sea ice habitat 
suitable for lairs.);
     Ice camp deployment must begin no later than mid-February 
2022, and be gradual, with activity increasing over the first five 
days. Camp deployment must be completed by March 15, 2022. (This 
schedule should discourage seals from establishing birthing lairs in or 
near the ice camp, and would allow ringed seals to relocate outside of 
the ice camp area as needed, though as stated above, both are unlikely. 
Based on the best available science, Arctic ringed seal whelping is not 
expected to occur prior to mid-March, and therefore, construction of 
the ice camp would be completed prior to whelping in the area of 
ICEX22. As such, pups are not anticipated to be in the vicinity of the 
camp at commencement, and mothers would not need to move newborn pups 
due to construction of the camp.);
     Personnel on all on-ice vehicles must observe for marine 
and terrestrial animals;
     Snowmobiles must follow established routes, when 
available. On-ice vehicles must not be used to follow any animal, with 
the exception of actively deterring polar bears if the situation 
requires;
     Personnel on foot and operating on-ice vehicles must avoid 
areas of deep snowdrifts near pressure ridges. (These areas are 
preferred areas for subnivean lair development.);
     Personnel must maintain a 100 m (328 ft) avoidance 
distance from all observed mammals; and
     All material (e.g., tents, unused food, excess fuel) and 
wastes (e.g., solid waste, hazardous waste) must be removed from the 
ice floe upon completion of ICEX22 activities.
    NMFS proposes requiring the following mitigation measures for 
activities involving acoustic transmissions (further explanation of 
certain mitigation measures is provided in parentheses following the 
measure):
     Personnel must begin passive acoustic monitoring (PAM) for 
vocalizing marine mammals 15 minutes prior to the start of activities 
involving active acoustic transmissions from submarines and exercise 
weapons.
     Personnel must delay active acoustic transmissions and 
exercise weapon launches if a marine mammal is detected during pre-
activity PAM and must shutdown active acoustic transmissions if a 
marine mammal is detected during acoustic transmissions.
     Personnel must not restart acoustic transmissions or 
exercise weapon launches until 15 minutes have passed with no marine 
mammal detections.
    Ramp up procedures for acoustic transmissions are not proposed as 
the Navy determined, and NMFS concurs, that they would result in 
impacts on military readiness and on the realism of training that would 
be impracticable.
    NMFS proposes requiring the following mitigation measures for 
aircraft activities to prevent incidental take of marine mammals due to 
the presence of aircraft and associated noise.
     Fixed wing aircraft must operate at highest altitudes 
practicable taking into account safety of personnel, meteorological 
conditions, and need to support safe operations of a drifting ice camp. 
Aircraft must not reduce altitude if a seal is observed on the ice. In 
general, cruising elevation must be 305 m (1,000 ft) or higher.
     Unmanned Aircraft Systems (UASs) must maintain a minimum 
altitude of at least 15.2 m (50 ft) above the ice. They

[[Page 70471]]

must not be used to track or follow marine mammals.
     Helicopter flights must use prescribed transit corridors 
when traveling to or from Prudhoe Bay and the ice camp. Helicopters 
must not hover or circle above marine mammals or within 457 m (1,500 
ft) of marine mammals.
     Aircraft must maintain a minimum separation distance of 
1.6 km (1 mi) from groups of 5 or more seals.
     Aircraft must not land on ice within 800 m (0.5 mi) of 
hauled-out seals.
    Based on our evaluation of the Navy's proposed mitigation measures, 
as well as other measures considered by NMFS, NMFS has preliminarily 
determined that the proposed mitigation measures provide the means of 
effecting the least practicable impact on the affected species or 
stocks and their habitat, paying particular attention to rookeries, 
mating grounds, and areas of similar significance.

Proposed Monitoring and Reporting

    In order to issue an IHA for an activity, section 101(a)(5)(D) of 
the MMPA states that NMFS must set forth requirements pertaining to the 
monitoring and reporting of such taking. The MMPA implementing 
regulations at 50 CFR 216.104(a)(13) require requests for 
authorizations to include the suggested means of accomplishing the 
necessary monitoring and reporting that will result in increased 
knowledge of the species and of the level of taking or impacts on 
populations of marine mammals that are expected to be present in the 
area of the specified activity. Effective reporting is critical both to 
compliance as well as ensuring that the most value is obtained from the 
required monitoring.
    Monitoring and reporting requirements prescribed by NMFS should 
contribute to improved understanding of one or more of the following:
     Occurrence of marine mammal species or stocks in the area 
in which take is anticipated (e.g., presence, abundance, distribution, 
density).
     Nature, scope, or context of likely marine mammal exposure 
to potential stressors/impacts (individual or cumulative, acute or 
chronic), through better understanding of: (1) Action or environment 
(e.g., source characterization, propagation, ambient noise); (2) 
affected species (e.g., life history, dive patterns); (3) co-occurrence 
of marine mammal species with the action; or (4) biological or 
behavioral context of exposure (e.g., age, calving, or feeding areas).
     Individual marine mammal responses (behavioral or 
physiological) to acoustic stressors (acute, chronic, or cumulative), 
other stressors, or cumulative impacts from multiple stressors.
     How anticipated responses to stressors impact either: (1) 
Long-term fitness and survival of individual marine mammals; or (2) 
populations, species, or stocks.
     Effects on marine mammal habitat (e.g., marine mammal prey 
species, acoustic habitat, or other important physical components of 
marine mammal habitat).
     Mitigation and monitoring effectiveness.
    The U.S. Navy has coordinated with NMFS to develop an overarching 
program, the Integrated Comprehensive Monitoring Program (ICMP), 
intended to coordinate marine species monitoring efforts across all 
regions and to allocate the most appropriate level and type of effort 
for each range complex based on a set of standardized objectives, and 
in acknowledgement of regional expertise and resource availability. The 
ICMP was created in direct response to Navy permitting requirements 
established in various MMPA regulations and ESA consultations. As a 
framework document, the ICMP applies by regulation to those activities 
on ranges and operating areas for which the Navy is seeking or has 
sought incidental take authorizations.
    The ICMP is focused on Navy training and testing ranges where the 
majority of Navy activities occur regularly, as those areas have the 
greatest potential for being impacted by the Navy's activities. In 
comparison, ICEX is a short duration exercise that occurs approximately 
every other year. Due to the location and expeditionary nature of the 
ice camp, the number of personnel onsite is extremely limited and is 
constrained by the requirement to be able to evacuate all personnel in 
a single day with small planes. As such, the Navy asserts that a 
dedicated monitoring project would not be feasible as it would require 
additional personnel and equipment.
    The Navy would conduct the following monitoring and reporting under 
the proposed IHA. In the event that personnel discover an injured or 
dead marine mammal, personnel must report the incident to the Office of 
Protected Resources (OPR), NMFS and to the Alaska regional stranding 
network as soon as feasible. The report must include the following 
information:
     Time, date, and location (latitude/longitude) of the first 
discovery (and updated location information if known and applicable);
     Species identification (if known) or description of the 
animal(s) involved;
     Condition of the animal(s) (including carcass condition if 
the animal is dead);
     Observed behaviors of the animal(s), if alive;
     If available, photographs or video footage of the 
animal(s); and
     General circumstances under which the animal(s) was 
discovered (e.g., during submarine activities, observed on ice floe, or 
by transiting aircraft).
    In addition, the Navy would be required to provide NMFS with a 
draft exercise monitoring report within 90 days of the conclusion of 
the specified activity. A final report must be prepared and submitted 
within 30 calendar days following receipt of any NMFS comments on the 
draft report. If no comments are received from NMFS within 30 calendar 
days of receipt of the draft report, the report shall be considered 
final. The report would include the number of marine mammals sighted, 
by species, and any other available information about the sighting(s) 
such as date, time, and approximate location (latitude and longitude).
    All sonar usage would be collected via the Navy's Sonar Positional 
Reporting System database. The Navy would be required to provide data 
regarding sonar use and the number of shutdowns during ICEX22 
monitoring in the Atlantic Fleet Training and Testing (AFTT) Letter of 
Authorization 2023 annual classified report. The Navy would also be 
required to analyze any declassified underwater recordings collected 
during ICEX22 for marine mammal vocalizations and report that 
information to NMFS, including the types and natures of sounds heard 
(e.g., clicks, whistles, creaks, burst pulses, continuous, sporadic, 
strength of signal) and the species or taxonomic group (if 
determinable). This information would also be submitted to NMFS with 
the 2023 annual AFTT declassified monitoring report.

Negligible Impact Analysis and Determination

    NMFS has defined negligible impact as an impact resulting from the 
specified activity that cannot be reasonably expected to, and is not 
reasonably likely to, adversely affect the species or stock through 
effects on annual rates of recruitment or survival (50 CFR 216.103). A 
negligible impact finding is based on the lack of likely adverse 
effects on annual rates of recruitment or survival (i.e., population-
level effects). An estimate of the number of takes alone is not enough 
information

[[Page 70472]]

on which to base an impact determination. In addition to considering 
estimates of the number of marine mammals that might be ``taken'' 
through harassment, NMFS considers other factors, such as the likely 
nature of any responses (e.g., intensity, duration), the context of any 
responses (e.g., critical reproductive time or location, migration), as 
well as effects on habitat, and the likely effectiveness of the 
mitigation. We also assess the number, intensity, and context of 
estimated takes by evaluating this information relative to population 
status. Consistent with the 1989 preamble for NMFS's implementing 
regulations (54 FR 40338; September 29, 1989), the impacts from other 
past and ongoing anthropogenic activities are incorporated into this 
analysis via their impacts on the environmental baseline (e.g., as 
reflected in the regulatory status of the species, population size and 
growth rate where known, ongoing sources of human-caused mortality, or 
ambient noise levels).
    Underwater acoustic transmissions associated with ICEX22, as 
outlined previously, have the potential to result in Level B harassment 
of ringed seals in the form of TTS and behavioral disturbance. No take 
by Level A harassment, serious injury, or mortality are anticipated to 
result from this activity. Further, at close ranges and high sound 
levels approaching those that could cause PTS, seals would likely avoid 
the area immediately around the sound source.
    NMFS estimates 910 takes of ringed seals by TTS from the submarine 
activities. TTS is a temporary impairment of hearing and can last from 
minutes or hours to days (in cases of strong TTS). In many cases, 
however, hearing sensitivity recovers rapidly after exposure to the 
sound ends. This activity has the potential to result in only minor 
levels of TTS, and hearing sensitivity of affected animals would be 
expected to recover quickly. Though TTS may occur as indicated, the 
overall fitness of the impacted individuals is unlikely to be affected 
given the temporary nature of TTS and the minor levels of TTS expected 
from these activities. Negative impacts on the reproduction or survival 
of affected ring seals as well as impacts on the stock are not 
anticipated.
    Effects on individuals that are taken by Level B harassment by 
behavioral disturbance could include alteration of dive behavior, 
alteration of foraging behavior, effects to breathing, interference 
with or alteration of vocalization, avoidance, and flight. More severe 
behavioral responses are not anticipated due to the localized, 
intermittent use of active acoustic sources and mitigation using PAM, 
which would limit exposure to active acoustic sources. Most likely, 
individuals would be temporarily displaced by moving away from the 
sound source. As described previously in the Acoustic Impacts section, 
seals exposed to non-impulsive sources with a received sound pressure 
level within the range of calculated exposures, (142-193 dB re 1 
[mu]Pa), have been shown to change their behavior by modifying diving 
activity and avoidance of the sound source (G[ouml]tz et al. 2010; 
Kvadsheim et al. 2010). Although a minor change to a behavior may occur 
as a result of exposure to the sound sources associated with the 
proposed specified activity, these changes would be within the normal 
range of behaviors for the animal (e.g., the use of a breathing hole 
further from the source, rather than one closer to the source). Thus, 
even repeated Level B harassment of some small subset of the overall 
stock is unlikely to result in any significant realized decrease in 
fitness for the affected individuals, and would not result in any 
adverse impact on reproduction or survival of affected individuals or 
to the stock as a whole.
    The Navy's proposed activities are localized and of relatively 
short duration. While the total ICEX22 Study Area is large, the Navy 
expects that most activities would occur within the Ice Camp Study Area 
in relatively close proximity to the ice camp. The larger Navy Activity 
Study Area depicts the range where submarines may maneuver during the 
exercise. The ice camp would be in existence for up to six weeks with 
acoustic transmission occurring intermittently over approximately four 
weeks.
    The project is not expected to have significant adverse effects on 
marine mammal habitat. The project activities are limited in time and 
would not modify physical marine mammal habitat. While the activities 
may cause some fish to leave a specific area ensonified by acoustic 
transmissions, temporarily impacting marine mammals' foraging 
opportunities, these fish would likely return to the affected area. As 
such, the impacts to marine mammal habitat are not expected to cause 
significant or long-term negative consequences.
    For on-ice activity, Level A harassment, Level B harassment, 
serious injury, and mortality are not anticipated, given the nature of 
the activities, the lack of previous ringed seal observations, and the 
mitigation measures NMFS has proposed to include in the IHA. The ringed 
seal pupping season on the ice lasts for five to nine weeks during late 
winter and spring. As stated in the Potential Effects of Specified 
Activities on Marine Mammals and Their Habitat section, March 1 is 
generally expected to be the onset of ice seal lairing season. The ice 
camp and runway would be established on multi-year ice without pressure 
ridges, where ringed seals tend to build their lairs. Ice camp 
deployment would begin mid-February, and be gradual, with activity 
increasing over the first five days. This schedule is expected to 
discourage seals from establishing birthing lairs near the ice camp, 
and would allow ringed seals to relocate outside of the ice camp area 
as needed (though as stated above, such instances are unlikely given 
the low average density of structures, the lack of previous ringed 
seals observations on the ice during ICEX activities, and proposed 
mitigation requirements that would require the Navy to construct the 
ice camp and runway on first-year or multiyear ice without pressure 
ridges). Ice camp deployment would be completed by March 15, before the 
pupping season. This would allow ringed seals to avoid the ice camp 
area once the pupping season begins, thereby avoiding potential impacts 
to nursing mothers and pups. Furthermore, ringed seal mothers are known 
to physically move pups from the birth lair to an alternate lair to 
avoid predation. If a ringed seal mother perceives the acoustic 
transmissions as a threat, the local network of multiple birth and 
haulout lairs would allow the mother and pup to move to a new lair.
    Mitigation measures would also avoid damage to and disturbance of 
ringed seals and their lairs that could otherwise result from on-ice 
activities. Personnel on on-ice vehicles would observe for marine 
mammals, and would follow established routes when available, to avoid 
potential damage to or disturbance of lairs. Personnel on foot and 
operating on-ice vehicles would avoid deep snow drifts near pressure 
ridges, also to avoid potential damage to or disturbance of lairs. 
Further, personnel would maintain a 100 m distance from all observed 
marine mammals to avoid disturbing the animals due to the personnel's 
presence. Implementation of these measures would prevent ringed seal 
lairs from being crushed or damaged during ICEX22 activities and would 
prevent seals and pups from abandoning and relocating to different 
lairs due to on-ice activities.
    There is an ongoing UME for ice seals, including ringed seals. 
Elevated

[[Page 70473]]

strandings have occurred in the Bering and Chukchi Seas since June 
2018. As of November 17, 2021, 95 ringed seal strandings have occurred, 
which is well below the partial abundance estimate of 171,418 ringed 
seals in the Arctic stock. The take proposed for authorization here 
does not provide a concern for any of these populations when considered 
in the context of these UMEs, especially given that the anticipated 
Level B harassment is unlikely to affect the reproduction or survival 
of any individuals. In addition, the ICEX22 Study Area is in the Arctic 
Ocean, well north and east of the primary area where seals have 
stranded along the western coast of Alaska (see map of strandings at: 
https://www.fisheries.noaa.gov/alaska/marine-life-distress/2018-2021-ice-seal-unusual-mortality-event-alaska). No Level A harassment, 
serious injury, or mortality is expected or proposed for authorization 
here, and take by Level B harassment of ringed seals would be reduced 
to the level of least practicable adverse impact through the 
incorporation of mitigation measures. As such, the proposed takes by 
Level B harassment of ringed seals are not expected to exacerbate or 
compound the ongoing UME.
    In summary and as described above, the following factors primarily 
support our preliminary determination that the impacts resulting from 
this activity are not expected to adversely affect the species or stock 
through effects on annual rates of recruitment or survival:
     No Level A harassment (injury), serious injury, or 
mortality is anticipated or proposed for authorization;
     Impacts would be limited to Level B harassment, primarily 
in the form of behavioral disturbance that results in minor changes in 
behavior;
     TTS is expected to affect only a limited number of animals 
(approximately 0.5 percent of the partial stock abundance described in 
Table 1) and TTS is expected to be minor and short term;
     The number of takes proposed to be authorized are low 
relative to the estimated abundances of the affected stock;
     Submarine training and testing activities would occur over 
only four weeks of the total six-week activity period;
     There would be no loss or modification of ringed seal 
habitat and minimal, temporary impacts on prey;
     Physical impacts to ringed seal subnivean lairs would be 
avoided; and
     Mitigation requirements for ice camp activities would 
prevent impacts to ringed seals during the pupping season.
    Based on the analysis contained herein of the likely effects of the 
specified activity on marine mammals and their habitat, and taking into 
consideration the implementation of the proposed monitoring and 
mitigation measures, NMFS preliminarily finds that the total marine 
mammal take from the proposed activity will have a negligible impact on 
the Arctic stock of ringed seals.

Unmitigable Adverse Impact Analysis and Determination

    In order to issue an IHA, NMFS must find that the specified 
activity will not have an ``unmitigable adverse impact'' on the 
subsistence uses of the affected marine mammal species or stocks by 
Alaska Natives. NMFS has defined ``unmitigable adverse impact'' in 50 
CFR 216.103 as an impact resulting from the specified activity: (1) 
That is likely to reduce the availability of the species to a level 
insufficient for a harvest to meet subsistence needs by: (i) Causing 
the marine mammals to abandon or avoid hunting areas; (ii) Directly 
displacing subsistence users; or (iii) Placing physical barriers 
between the marine mammals and the subsistence hunters; and (2) That 
cannot be sufficiently mitigated by other measures to increase the 
availability of marine mammals to allow subsistence needs to be met.
    Impacts to marine mammals from the specified activity would mostly 
include limited, temporary behavioral disturbances of ringed seals; 
however, some TTS is also anticipated. No Level A harassment (injury), 
serious injury, or mortality of marine mammals is expected or proposed 
for authorization, and the activities are not expected to have any 
impacts on reproductive or survival rates of any marine mammal species.
    The proposed specified activity and associated harassment of ringed 
seals are not expected to impact marine mammals in numbers or locations 
sufficient to reduce their availability for subsistence harvest given 
the short-term, temporary nature of the activities, and the distance 
offshore from known subsistence hunting areas. The specified activity 
would occur for a brief period of time outside of the primary 
subsistence hunting season, and though seals are harvested for 
subsistence uses off the North Slope of Alaska, the ICEX22 Study Area 
is seaward of subsistence hunting areas.
    The Navy plans to provide advance public notice to local residents 
and other users of the Prudhoe Bay region of Navy activities and 
measures used to reduce impacts on resources. This includes 
notification to local Alaska Natives who hunt marine mammals for 
subsistence. If any Alaska Natives express concerns regarding project 
impacts to subsistence hunting of marine mammals, the Navy would 
further communicate with the concerned individuals or community. The 
Navy would provide project information and clarification of any 
mitigation measures that may reduce impacts to marine mammals.
    Based on the description of the specified activity, and the 
proposed mitigation and monitoring measures, NMFS has preliminarily 
determined that there will not be an unmitigable adverse impact on 
subsistence uses from the Navy's proposed activities.

Endangered Species Act

    Section 7(a)(2) of the Endangered Species Act of 1973 (ESA: 16 
U.S.C. 1531 et seq.) requires that each Federal agency insure that any 
action it authorizes, funds, or carries out is not likely to jeopardize 
the continued existence of any endangered or threatened species or 
result in the destruction or adverse modification of designated 
critical habitat. To ensure ESA compliance for the issuance of IHAs, 
NMFS consults internally whenever we propose to authorize take for 
endangered or threatened species, in this case with NMFS' Alaska 
Regional Office (AKRO).
    The NMFS Office of Protected Resources (OPR) is proposing to 
authorize take of ringed seals, which are listed under the ESA. The OPR 
has requested initiation of Section 7 consultation with the AKRO for 
the issuance of this IHA. NMFS will conclude the ESA consultation prior 
to reaching a determination regarding the proposed issuance of the 
authorization.

Proposed Authorization

    As a result of these preliminary determinations, NMFS proposes to 
issue an IHA to the Navy for conducting submarine training and testing 
activities in the Arctic Ocean beginning in February 2022, provided the 
previously mentioned mitigation, monitoring, and reporting requirements 
are incorporated. A draft of the proposed IHA can be found at https://www.fisheries.noaa.gov/national/marine-mammal-protection/incidental-take-authorizations-military-readiness-activities.

Request for Public Comments

    We request comment on our analyses, the proposed authorization, and 
any other aspect of this notice of proposed

[[Page 70474]]

IHA for the proposed ICEX22 activities. We also request at this time 
comment on the potential Renewal of this proposed IHA as described in 
the paragraph below. Please include with your comments any supporting 
data or literature citations to help inform decisions on the request 
for this IHA or a subsequent Renewal IHA.
    On a case-by-case basis, NMFS may issue a one-time, one-year 
Renewal IHA following notice to the public providing an additional 15 
days for public comments when (1) up to another year of identical or 
nearly identical activities as described in the Description of Proposed 
Activity section of this notice is planned or (2) the activities as 
described in the Description of Proposed Activity section of this 
notice would not be completed by the time the IHA expires and a Renewal 
would allow for completion of the activities beyond that described in 
the Dates and Duration section of this notice, provided all of the 
following conditions are met:
     A request for renewal is received no later than 60 days 
prior to the needed Renewal IHA effective date (recognizing that the 
Renewal IHA expiration date cannot extend beyond one year from 
expiration of the initial IHA).
     The request for renewal must include the following:
    (1) An explanation that the activities to be conducted under the 
requested Renewal IHA are identical to the activities analyzed under 
the initial IHA, are a subset of the activities, or include changes so 
minor (e.g., reduction in pile size) that the changes do not affect the 
previous analyses, mitigation and monitoring requirements, or take 
estimates (with the exception of reducing the type or amount of take).
    (2) A preliminary monitoring report showing the results of the 
required monitoring to date and an explanation showing that the 
monitoring results do not indicate impacts of a scale or nature not 
previously analyzed or authorized.
     Upon review of the request for Renewal, the status of the 
affected species or stocks, and any other pertinent information, NMFS 
determines that there are no more than minor changes in the activities, 
the mitigation and monitoring measures will remain the same and 
appropriate, and the findings in the initial IHA remain valid.

    Dated: December 7, 2021.
Kimberly Damon-Randall,
Director, Office of Protected Resources, National Marine Fisheries 
Service.
[FR Doc. 2021-26762 Filed 12-9-21; 8:45 am]
BILLING CODE 3510-22-P