Takes of Marine Mammals Incidental to Specified Activities; Taking Marine Mammals Incidental to U.S. Navy 2020 Ice Exercise Activities in the Beaufort Sea and Arctic Ocean, 68886-68904 [2019-27124]

Agencies

• DEPARTMENT OF COMMERCE
• National Oceanic and Atmospheric Administration

[Federal Register Volume 84, Number 242 (Tuesday, December 17, 2019)]
[Notices]
[Pages 68886-68904]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2019-27124]


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DEPARTMENT OF COMMERCE

National Oceanic and Atmospheric Administration

[RTID 0648-XR067]


Takes of Marine Mammals Incidental to Specified Activities; 
Taking Marine Mammals Incidental to U.S. Navy 2020 Ice Exercise 
Activities in the Beaufort Sea and Arctic Ocean

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

ACTION: Notice; proposed incidental harassment authorization; request 
for comments on proposed authorization and possible renewal.

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SUMMARY: NMFS has received a request from the United States Department 
of the Navy (Navy) for authorization to take marine mammals incidental 
to Ice Exercise 2020 (ICEX20) 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-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 authorizations 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 (NDAA).

DATES: Comments and information must be received no later than January 
16, 2020.

ADDRESSES: Comments should be addressed to Jolie Harrison, Chief, 
Permits and Conservation Division, Office of Protected Resources, 
National Marine Fisheries Service. Physical comments should be sent to 
1315 East-West Highway, Silver Spring, MD 20910 and electronic comments 
should be sent 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 received electronically, 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/permit/incidental-take-authorizations-under-marine-mammal-protection-act 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: Amy Fowler, 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/permit/incidental-take-authorizations-under-marine-mammal-protection-act. 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 issued or, if the taking is limited to harassment, a notice of a 
proposed incidental take authorization may be provided to the public 
for review.
    Authorization for incidental takings shall be granted if NMFS finds 
that the

[[Page 68887]]

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 NDAA (Pub. L. 108-136) removed the ``small numbers'' and 
``specified geographical region'' limitations indicated above and 
amended the definition of ``harassment'' as it applies 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, we 
must review our proposed action (i.e., the issuance of an incidental 
harassment authorization) with respect to potential impacts on the 
human environment. NMFS plans to adopt the Navy's Supplemental 
Environmental Assessment/Overseas Environmental Assessment for Ice 
Exercise (Supplemental EA/OEA), as we have preliminarily determined 
that it includes adequate information analyzing the effects on the 
human environment of issuing the IHA. The Navy's Supplemental EA/OEA is 
posted online at https://www.nepa.navy.mil/icex. 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 July 3, 2019, 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 Beaufort Sea and Arctic Ocean north of Prudhoe Bay, Alaska. The 
application was deemed adequate and complete on November 22, 2019. The 
Navy's request is for take of a small number of ringed seals (Pusa 
hispida hispida) and bearded seals (Erignathus barbatus) by Level B 
harassment. Neither the Navy nor NMFS expect serious injury or 
mortality to result from this activity. Therefore, an IHA is 
appropriate.
    NMFS previously issued an IHA to the Navy for similar activities 
conducted in 2018 (83 FR 6522; February 14, 2018). The Navy complied 
with all the requirements (e.g., mitigation, monitoring, and reporting) 
of the previous IHA and information regarding their monitoring results 
may be found in the Estimated Take section.

Description of Proposed Activity

Overview

    The Navy proposes to conduct submarine training and testing 
activities from an ice camp established on an ice floe in the Beaufort 
Sea and Arctic Ocean for approximately six weeks beginning in February 
2020. Submarine active acoustic transmissions may result in occurrence 
of temporary hearing impairment (temporary threshold shift (TTS)) and 
behavioral harassment (Level B harassment) of ringed and bearded seals.

Dates and Duration

    The proposed action would occur over approximately a six-week 
period from February through April 2020, 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 for a period of one 
year from February 1, 2020 through January 31, 2021.

Specific 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 
total study area of 2,874,520 km\2\. The locations of the overall 
activity study area and ice camp study area are shown in Figure 2-1 of 
the Navy's application.

Detailed Description of Specific Activity

Ice Camp
    ICEX20 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 consists of a command hut, dining hut, 
sleeping quarters, a powerhouse, runway, and helipad. The number of 
structures and tents ranges from 15-20, and each tent is typically 2 
meters (m) by 6 m in size. The completed ice camp, including runway, is 
approximately 1.6 km in diameter. Support equipment for the ice camp 
includes 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). During flights between Deadhorse 
and the ice camp, aircraft would maintain an altitude of 1,000 ft (305 
m) or greater. Transit of aircraft between the mainland and the ice 
camp, use of snowmobiles and other equipment, and the footprint of the 
ice camp are not expected to result in take of marine mammals.
    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 100 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. The 
hydrophone network and acoustic communications between submarines and 
the ice camp are not expected to result in take of marine mammals.

[[Page 68888]]

Submarine Activities
    Submarine activities associated with ICEX20 generally entail safety 
maneuvers and active sonar use. These 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. Submarine training and testing 
involves active acoustic transmissions, which have the potential to 
harass marine mammals. Navy acoustic sources are categorized into 
``bins'' based on frequency, source level, and mode of usage 
(Department of the Navy 2015). The specifics of ICEX20 submarine 
acoustic sources are classified, including the designated bin(s).
Research Activities
    Personnel and equipment proficiency testing and multiple research 
and development activities would be conducted as part of ICEX20. 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 ICEX20 for research activities are considered de minimis. De 
minimis sources have 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 (Department of the Navy 2013). Additional 
information about ICEX20 research activities is located in Table 2-1 of 
the Navy's Supplemental EA/OEA. Research activities associated with 
ICEX20 are not expected to result in take of marine mammals and are not 
discussed further in this document.
    Proposed mitigation, monitoring, and reporting measures are 
described in detail later in this document (please see 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 ringed and bearded seals. 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 with expected potential for occurrence in 
the project area and summarizes information related to the population 
or stock, including regulatory status under the MMPA and ESA and 
potential biological removal (PBR), where known. For taxonomy, we 
follow Committee on Taxonomy (2018). 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 mortality or serious injury is anticipated or 
authorized here, PBR and annual serious injury and mortality from 
anthropogenic sources are included here as gross indicators of the 
status of the species and other threats.
    Marine mammal abundance estimates presented in this notice 
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., 2019). All values presented in 
Table 1 are the most recent available at the time of publication and 
are available in the 2018 Alaska SARs (Muto et al., 2019).

                                         Table 1--Marine Mammal Species Potentially Present in the Project Area
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                                                                                        ESA/ MMPA      Stock abundance
                                                                                         status;       (CV, Nmin, most                         Annual M/
           Common name               Scientific name               Stock              strategic (Y/    recent abundance           PBR            SI \3\
                                                                                         N) \1\          survey) \2\
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                                          Order Cetartiodactyla--Cetacea--Superfamily Mysticeti (baleen whales)
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Family Balaenidai:
    Bowhead whale................  Balaena mysticetus.  Western Arctic.............  E/D;Y           16,982 (0.058,       161................         44
                                                                                                      16,091, 2011).
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                                            Superfamily Odontoceti (toothed whales, dolphins, and porpoises)
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Family Delphinidae:
    Beluga whale.................  Delphinapterus       Beaufort Sea...............  -/-;N           39,258 (0.229,       649................        166
                                    leucas.                                                           32,453, 1992).
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                                                         Order Carnivora--Superfamily Pinnipedia
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Family Phocidae (earless seals):
    Ringed seal..................  Pusa hispida         Alaska.....................  T/D;Y           170,000 (-,          5,100 (Bering Sea-       1,054
                                    hispida.                                                          170,000, 2013)       U.S. portion only).
                                                                                                      (Bering Sea and
                                                                                                      Sea of Okhotsk
                                                                                                      only).
    Bearded seal.................  Erignathus barbatus  Alaska.....................  T/D;Y           299,174 (-,          8,210 (Bering Sea-         557
                                                                                                      273,676, 2012)       U.S. portion only).
                                                                                                      (Bering Sea-U.S.
                                                                                                      portion only).
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\1\ Endangered Species Act (ESA) status: Endangered (E), Threatened (T)/MMPA status: Depleted (D). A dash (-) indicates that the species is not listed
  under the ESA or designated as depleted under the MMPA. Under the MMPA, a strategic stock is one for which the level of direct human-caused mortality
  exceeds PBR or which is determined to be declining and likely to be listed under the ESA within the foreseeable future. Any species or stock listed
  under the ESA is automatically designated under the MMPA as depleted and as a strategic stock.
\2\ NMFS marine mammal stock assessment reports online at: www.nmfs.noaa.gov/pr/sars/. CV is coefficient of variation; Nmin is the minimum estimate of
  stock abundance. In some cases, CV is not applicable.

[[Page 68889]]

 
\3\ These values, found in NMFS's SARs, represent annual levels of human-caused mortality plus serious injury from all sources combined (e.g.,
  commercial fisheries, ship strike). Annual M/SI often cannot be determined precisely and is in some cases presented as a minimum value or range. A CV
  associated with estimated mortality due to commercial fisheries is presented in some cases.
Note: Italicized species are not expected to be taken or proposed for authorization.

    All species that could potentially occur in the proposed survey 
areas are included in Table 1. However, the temporal and/or spatial 
occurrence of bowhead whales and beluga whales is such that take is not 
expected to occur, and they are not discussed further beyond the 
explanation provided here. Bowhead whales migrate annually from 
wintering areas (December to March) in the northern Bering Sea, through 
the Chukchi Sea in the spring (April through May), to the eastern 
Beaufort Sea, where they spend much of the summer (June through early 
to mid-October) before returning again to the Bering Sea (Muto et al., 
2017). They are unlikely to be found in the ICEX20 study area during 
the February through April ICEX20 timeframe. Beluga whales follow a 
similar pattern, as they tend to spend winter months in the Bering Sea 
and migrate north to the eastern Beaufort Sea during the summer months.
    In addition, the polar bear (Ursus maritimus) may be found in the 
project area. However, polar bears are managed by the U.S. Fish and 
Wildlife Service and are not considered further in this document.

Bearded Seal

    Bearded seals are a boreoarctic species with circumpolar 
distribution (Burns 1967; Burns 1981; Burns and Frost 1979; Fedoseev 
1965; Johnson et al., 1966; Kelly 1988a; Smith 1981). Their normal 
range extends from the Arctic Ocean (85[deg] N) south to Sakhalin 
Island (45[deg] N) in the Pacific and south to Hudson Bay (55[deg] N) 
in the Atlantic (Allen 1880; King 1983; Smith 1981). Bearded seals are 
widely distributed throughout the northern Bering, Chukchi, and 
Beaufort Seas and are most abundance north of the ice edge zone 
(Macintyre et al., 2013). Bearded seals inhabit the seasonally ice-
covered seas of the Northern Hemisphere, where they whelp and rear 
their pups and molt their coats on the ice in the spring and early 
summer. The overall summer distribution is quite broad, with seals 
rarely hauled out on land, and some seals, mostly juveniles, may not 
follow the ice northward but remain near the coasts of the Bering and 
Chukchi seas (Burns 1967; Burns 1981; Heptner et al., 1976; Nelson 
1981). As the ice forms again in the fall and winter, most seals move 
south with the advancing ice edge through the Bering Strait into the 
Bering Sea where they spend the winter (Boveng and Cameron 2013; Burns 
and Frost 1979; Cameron and Boveng 2007; Cameron and Boveng 2009; Frost 
et al., 2005; Frost et al., 2008). This southward migration is less 
noticeable and predictable than the northward movements in late spring 
and early summer (Burns 1981; Burns and Frost 1979; Kelly 1988a). 
During winter, the central and northern parts of the Bering Sea shelf 
have the highest densities of bearded seals (Braham et al., 1981; Burns 
1981; Burns and Frost 1979; Fay 1974; Heptner et al., 1976; Nelson et 
al., 1984). In late winter and early spring, bearded seals are widely 
but not uniformly distributed in the broken, drifting pack ice ranging 
from the Chukchi Sea south to the ice front in the Bering Sea. In these 
areas, they tend to avoid the coasts and areas of fast ice (Burns 1967; 
Burns and Frost 1979).
    Bearded seals along the Alaskan coast tend to prefer areas where 
sea ice covers 70 to 90 percent of the surface, and are most abundant 
20 to 100 nm (37 to 185 km) offshore during the spring season (Bengston 
et al., 2000; Bengtson et al., 2005; Simpkins et al., 2003). In spring, 
bearded seals may also concentrate in nearshore pack ice habitats, 
where females give birth on the most stable areas of ice (Reeves et 
al., 2002). Bearded seals haul out on spring pack ice (Simpkins et al., 
2003) and generally prefer to be near polynyas (areas of open water 
surrounded by sea ice) and other natural openings in the sea ice for 
breathing, hauling out, and prey access (Nelson et al., 1984; Stirling 
1997). While molting between April and August, bearded seals spend 
substantially more time hauled out then at other times of the year 
(Reeves et al., 2002).
    In their explorations of the Canada Basin, Harwood et al. (2005) 
observed bearded seals in waters of less than 200 m during the months 
from August to September. These sightings were east of 140[deg] W. The 
Bureau of Ocean Energy Management conducted an aerial survey from June 
through October that covered the shallow Beaufort and Chukchi Sea shelf 
waters, and observed bearded seals from Point Barrow to the border of 
Canada (Clarke et al., 2014). The farthest from shore that bearded 
seals were observed was the waters of the continental slope.
    On December 28, 2012, NMFS listed both the Okhotsk and the Beringia 
distinct population segments (DPSs) of bearded seals as threatened 
under the ESA (77 FR 76740). The Alaska stock of bearded seals consists 
of only Beringia DPS seals.

Ringed Seal

    Ringed seals are the most common pinniped in the study area and 
have wide distribution in seasonally and permanently ice-covered waters 
of the Northern Hemisphere (North Atlantic Marine Mammal Commission 
2004). 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.
    Ringed seals have at least two distinct types of subnivean lairs: 
Haulout lairs and birthing lairs (Smith and Stirling 1975). Haulout 
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 (west of the ice camp), build their subnivean lairs on 
the pack ice near pressure ridges. Since subnivean lairs were found 
north of Barrow, Alaska, in pack ice, they are also assumed to be found 
within the sea ice in the ice camp proposed action 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 five to 
nine 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 1988a; Lydersen 
1998; Lydersen and Gjertz 1986; Smith and Stirling 1975), and such 
depths typically are found 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 seals are born beginning in March, but 
the majority of

[[Page 68890]]

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 1988b) and, therefore, are found in 
the study area (Figure 2-1 in Application). Passive acoustic monitoring 
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 the 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. (2010) tracked home ranges 
for ringed seals in the subnivean period (using shorefast ice); the 
size of the home ranges varied from less than 1 up to 27.9 km\2\; 
(median is 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., 2010). 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., 2010). The size of winter home ranges can, however, 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. Ringed seals may occur within the study area throughout the 
year and during the proposed action.
    In general, ringed seals prey on fish and crustaceans. Ringed seals 
are known to consume up to 72 different species in their diet; their 
preferred prey species is the polar cod (Jefferson et al., 2008). 
Ringed seals also prey upon a variety of other members of the cod 
family, including Arctic cod (Holst et al., 2001) and saffron cod, with 
the latter particularly important during the summer months in Alaskan 
waters (Lowry et al., 1980). Invertebrate prey seems to become 
prevalent in the ringed seals diet during the open-water season and 
often dominates the diet of young animals (Holst et al., 2001; Lowry et 
al., 1980). Large amphipods (e.g., Themisto libellula), krill (e.g., 
Thysanoessa inermis), mysids (e.g., Mysis oculata), shrimps (e.g., 
Pandalus spp., Eualus spp., Lebbeus polaris, and Crangon 
septemspinosa), and cephalopods (e.g., Gonatus spp.) are also consumed 
by ringed seals.
    Most taxonomists recognize five subspecies of ringed seals. The 
Arctic ringed seal subspecies occurs in the Arctic Ocean and Bering Sea 
and is the only stock that occurs in U.S. waters (referred to as the 
Alaska stock). NMFS listed the Arctic ringed seal subspecies as 
threatened under the ESA on December 28, 2012 (77 FR 76706), primarily 
due to anticipated loss of sea ice through the end of the 21st century.
    A comprehensive and reliable abundance estimate for the Alaska 
stock of ringed seals is not available. However, using data from 
surveys in the late 1990s and 2000 (Bengtson et al., 2005; Frost et 
al., 2004), Kelly et al. (2010) estimated the total population in the 
Alaska Chukchi and Beaufort seas to be at least 300,000 ringed seals. 
This is likely an underestimate since surveys in the Beaufort Sea were 
limited to within 40 km from shore (Muto et al., 2017). Conn et al. 
(2014) calculated an abundance estimate of about 170,000 ringed seals 
for the U.S. portion of the Bering Sea. This estimate did not account 
for availability bias and did not include ringed seals in the shorefast 
ice zone, which were surveyed using a different method. Thus, the 
actual number of ringed seals in the U.S. sector of the Bering Sea is 
likely much higher, perhaps by a factor of two or more (Muto et al., 
2017).

Ice Seals Unusual Mortality Event (UME)

    Since June 1, 2018, elevated strandings of ringed seals, bearded 
seals, and spotted seals (Phoca largha) have occurred in the Bering and 
Chukchi Seas. This event has been declared a 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 22, 2019, there have 
been at least 284 dead seals reported, with 119 stranding in 2018 and 
165 to date in 2019, which is nearly 10 times the average number of 
strandings of about 29 seals annually. 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 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 UME, and their physical characteristics, is not at all similar 
to the 2011-2016 UME, as the seals in 2018-2019 have not been 
exhibiting hair loss or skin lesions, which were a primary finding in 
the 2011-2016 UME. The investigation into the cause of the most recent 
UME is ongoing. More detailed information is available at: https://www.fisheries.noaa.gov/national/marine-life-distress/2018-2019-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.

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                  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 (dolphins,   150 Hz to 160 kHz.
 toothed whales, beaked whales,
 bottlenose whales).
High-frequency (HF) cetaceans (true       275 Hz to 160 kHz.
 porpoises, Kogia, river dolphins,
 cephalorhynchid, Lagenorhynchus
 cruciger & L. australis).
Phocid pinnipeds (PW) (underwater) (true  50 Hz to 86 kHz.
 seals).
Otariid pinnipeds (OW) (underwater) (sea  60 Hz to 39 kHz.
 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).

    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. 
Two species of phocid pinnipeds (ringed seal and bearded seal) have the 
reasonable potential to co-occur with the proposed survey activities. 
Please refer to Table 1.

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 [mu]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 study area, precipitation is unlikely to 
impact ambient sound;
     Biological: Marine mammals can contribute significantly to 
ambient noise

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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 study area as most anthropogenic activities will 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 (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 2003; 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 ICEX20 
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 U.S. Navy as part of the 
proposed action) 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 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 potentially result in 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

[[Page 68893]]

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 decibels above (a 40-dB threshold shift approximates 
PTS onset; e.g., Kryter et al., 1966; Miller, 1974) that 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 
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, and Yangtze finless porpoise (Neophocoena asiaeorientalis)) 
and three species of pinnipeds (northern elephant seal (Mirounga 
angustirostris), harbor seal, 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 showed 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

[[Page 68894]]

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 with 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 potential feeding disruption 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 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., 2007b). 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 activity), data suggest that exposures of 
pinnipeds to sources 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 grey (Halichoerus grypus) and harbor seals 
indicate avoidance response at received levels of 135-144

[[Page 68895]]

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 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 (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 action, 
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., 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 both bearded 
seals and 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. Bearded seals also spend a large amount of time hauled out 
during the molting season between April and August (Reeves et al., 
2002). 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), although the type of sound may 
be novel to them. 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, in all instances in which 
observed seals departed lairs in response to noise disturbance, they 
subsequently reoccupied the lair (Kelly et al., 1988).
    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 and icebreaking noise from this proposed action 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

[[Page 68896]]

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 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 and bearded 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 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, permanent 
threshold shift, temporary threshold shift, 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 action. 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 
action 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 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

[[Page 68897]]

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 32,000 fish species, 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; 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 study area are expected to hear the low-
frequency sources associated with the proposed action, but most are not 
expected to detect sounds above this threshold. 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 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 active sonar sources would be localized, 
temporary, and infrequent.
    Effects to 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 ICEX20 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 will be less 
than that ensonifying water under surrounding ice.
    Non-acoustic Impacts--Deployment of the ice camp could potentially 
affect ringed seal habitat by physically damaging or crushing subnivean 
lairs. These non-acoustic impacts could result in ringed seal injury or 
mortality. However, seals usually choose to locate lairs near pressure 
ridges, and the ice camp will be deployed in an area without pressure 
ridges in order to allow operation of an aircraft runway. Further, 
portable tents will be erected for lodging and operations purposes. 
Tents do not require building materials or typical construction 
methods. The tents are relatively easy to mobilize and will not be 
situated near areas featuring pressure ridges. Finally, the camp 
buildup will be gradual, with activity increasing over the first five 
days. This approach allows seals to move to different lair locations 
outside the ice camp area. Based on this information, we do not 
anticipate any damage to subnivean lairs that could result in ringed 
seal injury or mortality.
    ICEX20 personnel will be actively conducting testing and training 
operations on the sea ice and will travel around the camp area, 
including the runway, on snowmobiles. Although the Navy does not 
anticipate observing any seals on the ice, it is possible that the 
presence of active humans could behaviorally disturb ringed seals that 
are in lairs or on the ice. As discussed above, the camp will not be 
deployed in areas with pressure ridges and seals will have opportunity 
to move away from disturbances associated with human activity. 
Furthermore, camp personnel will maintain a 100-meter avoidance 
distance for all marine mammals on the ice. Based on this information, 
we do not believe the presence of humans on ice will result in take.
    Our preliminary determination of effects to the physical 
environment includes minimal possible impacts to marine mammals and 
their habitat from camp operation or deployment activities. In summary, 
given the relatively short duration of submarine testing and training 
activities, relatively small area that would be affected, and lack of 
physical impacts to habitat, the proposed actions are not likely to 
have a permanent, adverse effect on populations of prey species or 
marine mammal habitat. Therefore, any impacts to marine mammal habitat 
are not expected to cause significant or long-term consequences for 
individual ringed or bearded seals or their respective populations.

[[Page 68898]]

Estimated Take

    This section provides an estimate of the number of incidental takes 
proposed for authorization through this IHA, which will inform both 
NMFS' consideration of ``small numbers'' and 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 would be by Level B harassment only, in the form 
of disruption of behavioral patterns and 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, and described previously, no serious injury 
or mortality is anticipated or proposed to be authorized for this 
activity. Below we describe how the take is estimated.
    Generally speaking, we estimate take from exposure to sound by 
considering: (1) Acoustic thresholds above which NMFS believes the best 
available science indicates marine mammals will be behaviorally 
harassed or incur some degree of permanent hearing impairment; (2) the 
area or volume of water that will be ensonified above these levels in a 
day; (3) the density or occurrence of marine mammals within these 
ensonified areas; and, (4) and the number of days of activities. For 
the proposed IHA, the Navy employed a sophisticated model known as the 
Navy Acoustic Effects Model (NAEMO) for assessing the impacts of 
underwater sound.

Acoustic Thresholds

    Using the best available science, NMFS applies acoustic thresholds 
that identify the received level of underwater sound above which 
exposed marine mammals would be reasonably expected to be behaviorally 
harassed (equated to Level B harassment) or to incur PTS of some degree 
(equated to Level A harassment).
    Level B Harassment 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 action. The 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 passive acoustic monitoring of 
beaked whales during U.S. 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 U.S. 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 @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 has 
been 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. NMFS is proposing the use of this dose response 
function to predict behavioral harassment of pinnipeds for this 
activity.
    Level A harassment and TTS--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).

[[Page 68899]]

    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 analyses 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) 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 2016).
    Table 3 below provides the weighted criteria and thresholds used in 
this analysis for estimating quantitative acoustic exposures of marine 
mammals from the proposed action.

            Table 3--Injury (PTS) and Disturbance (TTS, Behavioral) Thresholds for Underwater Sounds
----------------------------------------------------------------------------------------------------------------
                                                                                  Physiological criteria
              Group                     Species           Behavioral     ---------------------------------------
                                                           criteria            Onset TTS           Onset PTS
----------------------------------------------------------------------------------------------------------------
Phocid (in water)...............  Ringed/Bearded      Pinniped Dose       181 dB SEL          201 dB SEL
                                   seal.               Response Function.  cumulative.         cumulative.
----------------------------------------------------------------------------------------------------------------

Quantitative Modeling

    The Navy performed a quantitative analysis to estimate the number 
of mammals that could be harassed by the underwater acoustic 
transmissions during the proposed action. Inputs to the quantitative 
analysis included marine mammal density estimates, marine mammal depth 
occurrence distributions (U.S Department of the Navy, in prep), 
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 action will occur (100-200 nm 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) and a maximum value of 0.0332 bearded seals per 
km\2\ in the cold and warm seasons. The density numbers are assumed 
static throughout the ice camp proposed action area for this species. 
The density data generated for this species was based on environmental 
variables known to exist within the proposed ice camp action area 
during the late winter/early springtime period.
    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. These tools and 
data sets serve are integral components of NAEMO. In NAEMO, animats are 
distributed non-uniformly based on

[[Page 68900]]

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 
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 few instances, although the activities 
themselves all occur within the study area, sound may propagate beyond 
the boundary of the study area. Any exposures occurring outside the 
boundary of the study area are counted as if they occurred within the 
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 these 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 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 are 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 passive acoustic monitoring.
    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 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 4 
provides range to effects for active acoustic sources proposed for 
ICEX20 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 4--Range to Behavioral Effects, TTS, and PTS in the ICEX Study Area
----------------------------------------------------------------------------------------------------------------
                                                                              Range to effects (m)
                       Source/exercise                        --------------------------------------------------
                                                                  Behavioral          TTS              PTS
----------------------------------------------------------------------------------------------------------------
Submarine Exercise...........................................      10,000 \a\            4,025               15
----------------------------------------------------------------------------------------------------------------
\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 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 animats 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 
this proposed action, the implementation of avoidance and mitigation 
factors were not included in this analysis.
    Table 5 shows the exposures expected for bearded and ringed seals 
based on NAEMO modeled results.

[[Page 68901]]



                Table 5--Quantitative Modeling Results of Potential Exposures for ICEX Activities
----------------------------------------------------------------------------------------------------------------
                                                        Level B harassment
                     Species                     --------------------------------     Level A          Total
                                                    Behavioral          TTS         harassment
----------------------------------------------------------------------------------------------------------------
Bearded seal....................................               3               1               0               4
Ringed seal.....................................           1,395              11               0           1,406
----------------------------------------------------------------------------------------------------------------

Effects of Specified Activities on Subsistence Uses of Marine Mammals

    Subsistence hunting is important for many Alaska Native 
communities. A study of the North Slope villages of Nuiqsut, Kaktovik, 
and Barrow identified the primary resources used for subsistence and 
the locations for harvest (Stephen R. Braund & Associates 2010), 
including terrestrial mammals (caribou, moose, wolf, and wolverine), 
birds (geese and eider), fish (Arctic cisco, Arctic char/Dolly Varden 
trout, and broad whitefish), and marine mammals (bowhead whale, ringed 
seal, bearded seal, and walrus). Of these species, only bearded and 
ringed seals would be located within the study area during the proposed 
action.
    The study area is at least 100-150 mi (161-241 km) from land, well 
seaward of known subsistence use areas and the planned activities would 
conclude prior to the start of the summer months, during which the 
majority of subsistence hunting would occur. In addition, the specified 
activity would not remove individuals from the population, therefore 
there would be no impacts caused by this action to the availability of 
bearded seals or ringed seals for subsistence hunting. Therefore, 
subsistence uses of marine mammals would not be impacted by this 
action.

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 NDAA for FY 2004 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), 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

    The following general mitigation actions are proposed for ICEX20 to 
minimize impacts on ringed and bearded seals on the ice floe:
     Camp deployment would begin in mid-February and would be 
completed by March 15. Based on the best available science, Arctic 
ringed seal whelping is not expected to occur prior to mid-March. 
Construction of the ice camp would be completed prior to whelping in 
the area of ICEX20. 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. Additionally, if a 
seal had a lair in the area they would be able to relocate. Completing 
camp deployment before ringed seal pupping begins will allow ringed 
seals to avoid the camp area prior to pupping and mating seasons, 
reducing potential impacts;
     Camp location will not be in proximity to pressure ridges 
in order to allow camp deployment and operation of an aircraft runway. 
This will minimize physical impacts to subnivean lairs;
     Camp deployment will gradually increase over five days, 
allowing seals to relocate to lairs that are not in the immediate 
vicinity of the camp;
     Personnel on all on-ice vehicles would observe for marine 
and terrestrial animals; any marine or terrestrial animal observed on 
the ice would be avoided by 328 ft (100 m). On-ice vehicles would not 
be used to follow any animal, with the exception of actively deterring 
polar bears if the situation requires;
     Personnel operating on-ice vehicles would avoid areas of 
deep snowdrifts near pressure ridges, which are preferred areas for 
subnivean lair development; and
     All material (e.g., tents, unused food, excess fuel) and 
wastes (e.g., solid waste, hazardous waste) would be removed from the 
ice floe upon completion of ICEX20.
    The following mitigation actions are proposed for ICEX20 activities 
involving acoustic transmissions:
     For activities involving active acoustic transmissions 
from submarines and torpedoes, passive acoustic sensors on the 
submarines will listen for vocalizing marine mammals for 15 minutes 
prior to the initiation of exercise activities. If a marine mammal is 
detected, the submarine will delay active transmissions, and not 
restart until after 15 minutes have passed with no marine mammal 
detections. If there are no animal detections, it may be assumed that 
the vocalizing animal is no longer in the immediate area and is 
unlikely to be subject to harassment. Ramp up procedures are not 
proposed as Navy determined, and NMFS accepts, that they would result 
in an unacceptable impact on readiness and on the realism of training.

[[Page 68902]]

    Based on our evaluation of the applicant's proposed measures, as 
well as other measures considered by NMFS, NMFS has preliminarily 
determined that the proposed mitigation measures provide the means 
effecting the least practicable impact on the affected species or 
stocks and their habitat, paying particular attention to rookeries, 
mating grounds, and areas of similar significance, and on the 
availability of such species or stock for subsistence uses.

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) indicate that requests for 
authorizations must include the suggested means of accomplishing the 
necessary monitoring and reporting that will result in increased 
knowledge of the species and of the level of taking or impacts on 
populations of marine mammals that are expected to be present in the 
proposed action area. 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 plan in which specific monitoring would occur. This plan is 
called the Integrated Comprehensive Monitoring Program (ICMP) (U.S. 
Department of the Navy 2011). The ICMP was created in direct response 
to Navy permitting requirements established in various MMPA rules, ESA 
consultations, and applicable regulations. 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 intended to coordinate monitoring efforts 
across all regions and to allocate the most appropriate level and type 
of effort based on set of standardized research goals, and in 
acknowledgement of regional scientific value and resource availability.
    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. ICEX20 in comparison 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, a dedicated monitoring project would not be 
feasible as it would require additional personnel and equipment to 
locate, tag and monitor the seals.
    The Navy is committed to documenting and reporting relevant aspects 
of training and research activities to verify implementation of 
mitigation, comply with current permits, and improve future 
environmental assessments. All sonar usage will be collected via the 
Navy's Sonar Positional Reporting System database and reported. If any 
injury or death of a marine mammal is observed during the 
ICEX20activity, the Navy will immediately halt the activity and report 
the incident to the Office of Protected Resources, NMFS, and the Alaska 
Regional Stranding Coordinator, NMFS. The following information must be 
provided:
     Time, date, and location of the discovery;
     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 vessel).
    The Navy will provide NMFS with a draft exercise monitoring report 
within 90 days of the conclusion of the planned activity. The draft 
exercise monitoring report will include data regarding sonar use and 
any mammal sightings or detection will be documented. The report will 
also include information on the number of sonar shutdowns recorded. If 
no comments are received from NMFS within 30 days of submission of the 
draft final report, the draft final report will constitute the final 
report. If comments are received, a final report must be submitted 
within 30 days after receipt of comments.

Negligible Impact Analysis and Determination

    NMFS has defined negligible impact as an impact resulting from the 
specified activity that cannot be reasonably expected to, and is not 
reasonably likely to, adversely affect the species or stock through 
effects on annual rates of recruitment or survival (50 CFR 216.103). A 
negligible impact finding is based on the lack of likely adverse 
effects on annual rates of recruitment or survival (i.e., population-
level effects). An estimate of the number of takes alone is not enough 
information on which to base an impact determination. In addition to 
considering estimates of the number of marine mammals that might be 
``taken'' through harassment, NMFS considers other factors, such as the 
likely nature of any 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

[[Page 68903]]

sources of human-caused mortality, or ambient noise levels).
    Underwater acoustic transmissions associated with ICEX20, as 
outlined previously, have the potential to result in Level B harassment 
of ringed and bearded seals in the form of TTS and behavioral 
disturbance. No serious injury, mortality or Level A takes are 
anticipated to result from this activity. At close ranges and high 
sound levels approaching those that could cause PTS, avoidance of the 
area immediately around the sound source would be seals' likely 
behavioral response.
    NMFS estimates 11 takes of ringed seals and 1 take of bearded seals 
due to TTS from the submarine activities. TTS is a temporary impairment 
of hearing and TTS 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 in up to 11 ringed seals and 1 bearded seal, the 
overall fitness of these individuals is unlikely to be affected and 
negative impacts to the entire stocks are not anticipated.
    Effects on individuals that are taken by Level B harassment 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 by passive acoustic monitoring which will limit 
exposure to sound sources. Most likely, individuals will be temporarily 
displaced by moving away from the sound source. As described previously 
in the behavioral effects 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 planned action, 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). 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 to the stock as a whole.
    The Navy's planned activities are localized and of relatively short 
duration. While the total project area is large, the Navy expects that 
most activities will occur within the ice camp action area in 
relatively close proximity to the ice camp. The larger study area 
depicts the range where submarines may maneuver during the exercise. 
The ice camp will 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, serious injury and mortality are not 
anticipated. Level B harassment could occur but is unlikely due to 
mitigation measures followed during the exercise. Foot and snowmobile 
movement on the ice will be designed to avoid pressure ridges, where 
ringed seals build their lairs; runways will be built in areas without 
pressure ridges; snowmobiles will follow established routes; and camp 
buildup is gradual, with activity increasing over the first five days 
providing seals the opportunity to move to a different lair outside the 
ice camp area. The Navy will also employ its standard 100-m avoidance 
distance from any arctic animals. Implementation of these measures 
should ensure that ringed seal lairs are not crushed or damaged during 
ICEX20 activities and minimize the potential for seals and pups to 
abandon lairs and relocate.
    The ringed seal pupping season on the ice lasts for five to nine 
weeks during late winter and spring. Ice camp deployment would begin in 
mid-February and be completed by March 15, before the pupping season. 
This will allow ringed seals to avoid the ice camp area once the 
pupping season begins, thereby reducing 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.
    There is an ongoing UME for ice seals, including ringed and bearded 
seals. Elevated strandings have occurred in the Bering and Chukchi Seas 
since June 2018. Though elevated numbers of seals have stranded during 
this UME, this event does not provide cause for concern regarding 
population-level impacts, as the population abundance estimates for 
each of the affected species number in the hundreds of thousands. The 
study area for ICEX20 activities is in the Beaufort Sea and 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/national/marine-life-distress/2018-2019-ice-seal-unusual-mortality-event-alaska). The location of the ICEX20 
activities, combined with the short duration and low-level potential 
effects on marine mammals, suggest that the proposed activities are not 
expected to contribute to 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 serious injury or mortality is anticipated or 
authorized;
     Impacts will be limited to Level B harassment, primarily 
in the form of behavioral disturbance;
     TTS is expected to affect only a limited number of 
animals;
     The number of takes proposed to be authorized are low 
relative to the estimated abundances of the affected stocks;
     There will be no loss or modification of ringed or bearded 
seal habitat and minimal, temporary impacts on prey;
     Physical impacts to ringed seal subnivean lairs will be 
avoided; and
     Mitigation requirements for ice camp activities would 
minimize impacts to animals 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 
all affected marine mammal species or stocks.

[[Page 68904]]

Unmitigable Adverse Impact Analysis and Determination

    Impacts to subsistence uses of marine mammals resulting from the 
proposed action are not anticipated. The proposed action would occur 
outside of the primary subsistence use season (i.e., summer months), 
and the study area is 100-150 mi (161-241 km) seaward of known 
subsistence use areas. Harvest locations for ringed seals extend up to 
80 nmi (148 km) from shore during the summer months while winter 
harvest of ringed seals typically occurs closer to shore. Additionally, 
no mortality or serious injury is expected or proposed to be 
authorized, and therefore no marine mammals would be removed from 
availability for subsistence. Based on this information, 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 (ESA)

    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, in this case with the NMFS Alaska Regional 
Office (AKR), whenever we propose to authorize take for endangered or 
threatened species.
    NMFS is proposing to authorize take of ringed seals and bearded 
seals, which are listed under the ESA. The Permits and Conservation 
Division has requested initiation of section 7 consultation with the 
Protected Resources Division of AKR 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 Beaufort Sea and Arctic Ocean beginning in February 
2020, 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/permit/incidental-take-authorizations-under-marine-mammal-protection-act.

Request for Public Comments

    We request comment on our analyses, the proposed authorization, and 
any other aspect of this Notice of Proposed IHA. We also request 
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.
    On a case-by-case basis, NMFS may issue a one-year IHA renewal with 
an additional 15 days for public comments when (1) another year of 
identical or nearly identical activities as described in the Specified 
Activities section of this notice is planned or (2) the activities as 
described in the Specified Activities 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 expiration of the current IHA.
     The request for renewal must include the following:
    (1) An explanation that the activities to be conducted under the 
requested renewal 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 
because only a subset of the initially analyzed activities remain to be 
completed under the Renewal); and
    (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 12, 2019.
Donna S. Wieting,
Director, Office of Protected Resources, National Marine Fisheries 
Service.
[FR Doc. 2019-27124 Filed 12-16-19; 8:45 am]
 BILLING CODE 3510-22-P