[Federal Register Volume 82, Number 201 (Thursday, October 19, 2017)]
[Notices]
[Pages 48683-48701]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2017-22637]


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DEPARTMENT OF COMMERCE

National Oceanic and Atmospheric Administration

RIN 0648-XF470


Takes of Marine Mammals Incidental to Specified Activities; 
Taking Marine Mammals Incidental to U.S. Navy 2018 Ice Exercise 
Activities in the Beaufort Sea and Arctic Ocean

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

ACTION: Proposed incidental harassment authorization (IHA); request for 
comments.

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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 2018 (ICEX18) activities proposed within the Beaufort 
Sea and Arctic Ocean 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 
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 a military readiness activity pursuant to the 
Marine Mammal Protection Act (MMPA), as amended by the National Defense 
Authorization Act for Fiscal Year 2004 (NDAA).

DATES: Comments and information must be received no later than November 
20, 2017.

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. Attachments 
to electronic comments will be accepted in Microsoft Word or Excel or 
Adobe PDF file formats only. All comments received are a part of the 
public record and will generally be posted online at www.nmfs.noaa.gov/pr/permits/incidental/military.htm 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: Rob Pauline, Office of Protected 
Resources, NMFS, (301) 427-8408. 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: www.nmfs.noaa.gov/pr/permits/incidental/military.htm. In case of problems accessing these documents, 
please call the contact listed above.

SUPPLEMENTARY INFORMATION:

Background

    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 
authorization is provided to the public for review.

[[Page 48684]]

    An authorization for incidental takings shall be granted if NMFS 
finds that the taking will have a negligible impact on the species or 
stock(s), will not have an unmitigable adverse impact on the 
availability of the species or stock(s) for subsistence uses (where 
relevant), and if the permissible methods of taking and requirements 
pertaining to the mitigation, monitoring and reporting of such takings 
are set forth.
    NMFS has defined ``negligible impact'' in 50 CFR 216.103 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.
    The MMPA states that the term ``take'' means to harass, hunt, 
capture, kill or attempt to harass, hunt, capture, or kill any marine 
mammal.
    The MMPA defines ``harassment'' as: Any act of pursuit, torment, or 
annoyance which (i) has the potential to injure a marine mammal or 
marine mammal stock in the wild (Level A harassment); or (ii) has the 
potential to disturb a marine mammal or marine mammal stock in the wild 
by causing disruption of behavioral patterns, including, but not 
limited to, migration, breathing, nursing, breeding, or sheltering 
(Level B harassment).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'' to read as follows (Section 3(18)(B) of 
the MMPA): (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 such behavioral patterns are abandoned or significantly 
altered (Level B Harassment).

National Environmental Policy Act

    To comply with the National Environmental Policy Act of 1969 (NEPA; 
42 U.S.C. Sec. Sec.  4321 et seq.) and NOAA Administrative Order (NAO) 
216-6A, NMFS must review our proposed action (i.e., the issuance of an 
incidental harassment authorization) with respect to environmental 
consequences on the human environment.
    The Navy is currently preparing an environmental assessment (EA) 
titled Environmental Assessment/Overseas Environmental Assessment for 
Ice Exercise. Once the EA is finalized, NMFS plans to adopt the Navy's 
EA, provided our independent evaluation of the document finds that it 
includes adequate information analyzing the effects on the human 
environment of issuing the IHA.
    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 April 12, 2017, NMFS received a request from the Navy for the 
taking of 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 
Navy's request is for take of ringed seals (Pusa hispida hispida) by 
Level B harassment. Neither the Navy nor NMFS expects Level A take or 
mortality to result from this activity and, therefore, an IHA is 
appropriate.

Description of Proposed Activity

Overview

    The Navy proposes to conduct submarine training and testing 
activities from an ice camp stationed on an ice floe in the Beaufort 
Sea and Arctic Ocean for six weeks between February and April 2018. 
Active acoustic transmissions (low, mid, and high-frequency) may result 
in the occurrence of temporary hearing impairment (temporary threshold 
shift (TTS)) and behavioral harassment of ringed seals.

Dates and Duration

    The proposed action would occur over approximately a six-week 
period from February through April 2018, 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 valid from February 1, 2018 
through May 1, 2018.

Specific Geographic Region

    The ice camp would be established approximately 100-200 nmi (185-
370 kilometers (km)) north of Prudhoe Bay, Alaska. The exact location 
cannot be identified ahead of time as required conditions (e.g., ice 
cover) cannot be forecasted until exercises are expected to commence. 
The vast majority of submarine training and testing would occur near 
the ice camp. The ice camp action area is comprised of 27,171 square 
miles (mi\2\) or 70,374 square kilometers (km\2\) of ice and open 
water. However, limited submarine training and testing may occur 
intermittently throughout the deep Arctic Ocean basin near the North 
Pole, within the total study area of 1,109,858 mi\2\ (2,874,520 km\2\) 
as shown in Figure 2-1 in the Application). The ice camp itself will be 
no more than 1 mi (1.6 km) in diameter and 0.77 mi\2\ (2 km\2\) in 
area.

Detailed Description of Specific Activities

    ICEX18 includes the deployment of a temporary camp situated on an 
ice floe. The camp will consist of a series of portable tents. In the 
past, the Navy would construct temporary wooden structures at ICEX 
camps, but they no longer do so. A portable tracking range for 
submarine training and testing would be installed near the ice camp. 
Eight hydrophones, located on the ice and extending to 30 meters (m) 
below the ice, would be deployed by drilling 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 (Figure 1-2 in 
Application) while the remaining four 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 testing schedule with the submarines; an underwater 
telephone would be used as a backup to the acoustic communications.
    Submarine activities associated with ICEX18 are classified, but 
generally entail safety maneuvers, active sonar use and exercise 
torpedo use. These maneuvers and sonar use are similar to submarine 
activities conducted in other undersea environments. They are being 
conducted in the Arctic to test their performance in a cold 
environment.
    Submarine training and testing activities generate acoustic 
transmissions that may impact marine mammals. Some acoustic sources 
either are above the known hearing range of marine species or have 
narrow beam widths and short pulse lengths that would not result in 
effects to marine species. Potential effects from these de minimis 
sources are analyzed qualitatively in accordance with current Navy 
policy. Navy acoustic sources are categorized into ``bins'' based on 
frequency, source level, and mode of usage, as previously established 
by the Navy (Department of the Navy 2015). The acoustic transmissions 
associated

[[Page 48685]]

with submarine training fall within bins HF1 (hull-mounted submarine 
sonars that produce high-frequency (greater than 10 kilohertz (kHz) but 
less than 200 kHz) signals)), M3 (mid-frequency (1-10 kHz) acoustic 
modems greater than 190 decibel (dB) re 1micropascal ([mu]Pa)), and 
TORP2 (heavyweight torpedo). As, described below, transmissions are 
associated with discrete events that may last up to 24 hours. Time 
between events would not have acoustic transmissions.
    Active buoys and moored sources would be used during ICEX18. One 
active buoy would be the Autonomous Reverberation Measurement System, 
which would be attached to the bottom of the ice and may be active for 
up to 30 days of ICEX18. Additionally, a Massachusetts Institute of 
Technology/Lincoln Lab vertical line array would be deployed through a 
hole in the ice to a source depth of 150 meters (m). This array would 
have continuous wave and chirp transmission capability. The continuous 
wave and chirp transmissions would both be active for no more than 8 
days during ICEX18. Over one day of testing (i.e., 24-hour period), he 
continuous wave source will continuously transmit for 4 hours, the 
chirp will then transmit for 15 seconds on and 45 seconds off for 4 
hours, and the sources will then be silent for 16 hours.
    The Naval Research Laboratory would also utilize an unmanned 
underwater vehicle for the deployment of a synthetic aperture source 
(SAS), which would transmit for 24 hours per day for up to 4 days. The 
SAS would be used to make measurements of the acoustic interaction with 
the ice/water interface. Source parameters, including active sonar 
transmissions from submarines and torpedoes, are classified. Additional 
details for the active sources described above can be found in Table 1.

                                     Table 1--Active Acoustic Parameters for ICEX18 Training and Testing Activities
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                                                                  Frequency      Source          Pulse length        Duty cycle
   Command or research institution            Source name        range (kHz)   level (dB)       (milliseconds)       (percent)         Source type
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U.S. Fleet Forces....................  Exercise Torpedo........                                        Classified.
                                                                ----------------------------------------------------------------------------------------
Office of Naval Research.............  Autonomous Reverberation       3 to 6          200  1,000..................         1.67  Moored.
                                        Measurement System.
                                                                ----------------------------------------------------------------------------------------
Naval Research Laboratory............  SAS.....................                            Classified                            Unmanned Underwater
                                                                                                                                  Vehicle (UUV).
                                                                ----------------------------------------------------------------------------------------
Massachusetts Institute of Technology/ Continuous Wave *.......  0.20 to 1.2          190  continuous.............          100  Moored.
 Lincoln Labs.                         Chirp *.................  0.25 to 1.2          190  15,000.................           25  Moored.
--------------------------------------------------------------------------------------------------------------------------------------------------------
* Both sources are located on the Massachusetts Institute of Technology/Lincoln Labs deployed vertical line array.

    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 seals (Pusa hispida hispida), 
which is the only potentially affected species. Other marine mammal 
species that may occur in the study area include bowhead whales 
(Balaena mysticetus), beluga whales (Delphinapterus leucas), and 
bearded seals (Erignathus barbatus). 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 ICEX18 study area 
during the February through April ICEX18 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 the fall and winter, Bearded seals also move south 
with the advancing ice edge through the Bering Strait into the Bering 
Sea where they spend the winter (Muto et al. 2016). While these species 
are often observed in areas of sea ice, they require access to some 
open water (e.g. leads, polynyas) in order to breath. The Navy proposes 
to establish its ice camp and conduct operations in late winter when 
the extent and thickness of the Arctic ice pack is peaking. The ice 
camp will be located on a multi-year ice floe without cracks or leads 
that can support a runway for aircraft. Only ringed seals are able to 
create and maintain their own breathing holes and, therefore, may 
inhabit areas featuring thick multi-year ice. Additional information 
regarding population trends and threats may be found in NMFS's Stock 
Assessment Reports (SAR; www.nmfs.noaa.gov/pr/sars/) and more general 
information about this species (e.g., physical and behavioral 
descriptions) may be found on NMFS's Web site (www.nmfs.noaa.gov/pr/species/mammals/).
    Table 2 lists all of the species that could occur in the project 
area and summarizes information related to the population or stock, 
including regulatory status under the MMPA and the Endangered Species 
Act (ESA) and potential biological removal (PBR). Only the ringed seal, 
however, is expected to occur in the project area during the time of 
year when project activities would take place. For taxonomy, we follow 
Committee on Taxonomy (2016). 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 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.
    The marine mammal abundance estimates presented in this document 
represents 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. The

[[Page 48686]]

managed stocks in this region are assessed in NMFS's U.S. Alaska SARs 
(Muto et al., 2017). All values presented in Table 2 are the most 
recent available at the time of publication and are available in the 
2016 SARs (Muto et al., 2017) (available online at: www.nmfs.noaa.gov/pr/sars/)
    The only species that could potentially occur in the proposed 
survey area is the ringed seal. Total sea ice coverage is expected 
across the study area during the study period which precludes the 
presence of other arctic marine mammal species. As described below, 
ringed seals temporally and spatially co-occur with the activity to the 
degree that take is reasonably likely to occur, and therefore we have 
proposed authorizing take.

                                         Table 2--Marine Mammal Species Potentially Present in the Project Area
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                                                                                                    Stock abundance (CV,
                                                                                 ESA/MMPA status;     Nmin, most recent                          Annual
            Common name                Scientific name            Stock           strategic (Y/N)     abundance survey)            PBR          M/SI \3\
                                                                                        \1\                  \2\
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                          Order Cetartiodactyla--Cetacea--Superfamily Mysticeti (baleen whales)
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                    Family Balaenidai
--------------------------------------------------------------------------------------------------------------------------------------------------------
Bowhead whale.....................  Balaena mysticetus..  Western Arctic......  E/D;Y               16,982 (0.058,        161.................        44
                                                                                                     16,091, 2011).
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                            Superfamily Odontoceti (toothed whales, dolphins, and porpoises)
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                   Family Delphinidae
--------------------------------------------------------------------------------------------------------------------------------------------------------
Beluga whale......................  Delphinapterus        Beaufort Sea........  -/-;N               39,258 (0.229,        649.................       166
                                     leucas.                                                         32,453, 1992).
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                         Order Carnivora--Superfamily Pinnipedia
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                             Family Phocidae (earless seals)
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Ringed seal.......................  Pusa hispida hispida  Alaska..............  -/-;N               170,000 (Bering Sea   5,100 (Bearing Sea-      1,054
                                                                                                     and Sea of Okhotsk    U.S. portion only).
                                                                                                     only)--2013).
Bearded seal......................  Erignathus barbatus   Alaska..............  -/-;N               299,174 (-,273,676,   8,210...............       1.4
                                     nauticus.                                                       2012) (Bearing Sea-- (Bearing Sea--U.S.
                                                                                                     U.S. portion only).   portion only).
--------------------------------------------------------------------------------------------------------------------------------------------------------
\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 [explain if this is the case]
\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.

Ringed Seal

    Ringed seals are found in seasonally and permanently ice-covered 
waters of the Northern Hemisphere (North Atlantic Marine Mammal 
Commission 2004). The Alaska stock of ringed seals is found in the 
study area. Though a reliable population estimate for the entire Alaska 
stock is not available, research programs have recently developed new 
survey methods and partial, but useful, abundance estimates. In spring 
of 2012 and 2013, U.S. and Russian researchers conducted aerial 
abundance and distribution surveys of the entire Bering Sea and Sea of 
Okhotsk (Moreland et al., 2013). The data from these image-based 
surveys are still being analyzed, but Conn et al. (2014), using a very 
limited sub-sample of the data collected from the U.S. portion of the 
Bering Sea in 2012, calculated an abundance estimate of about 170,000 
ringed seals in the U.S. EEZ of the Bering Sea in late April. This 
estimate does 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. Using data from surveys by Bengtson et al. 
(2005) and Frost et al. (2004) in the late 1990s and 2000, Kelly et al. 
(2010) estimated the total population in the Alaska Chukchi and 
Beaufort seas to be at least 300,000 ringed seals (Muto et al., 2017). 
This is likely an underestimate since the Beaufort Sea surveys were 
limited to within 40 km of shore. Current and reliable data on trends 
in population abundance for the Alaska stock of ringed seals are 
unavailable. A minimum population estimate (Nmin) and PBR 
value are also unavailable. A PBR for only those ringed seals in the 
U.S. portion of the Bering Sea is 5,100 ringed seals. The total 
estimated annual level of human-caused mortality and serious injury is 
1,062 (Muto et al., 2016). Since the level of human-caused mortality is 
considerably less than the PBR, the stock is not likely to be declining 
due to direct human actions (e.g. subsistence hunting) and the stock is 
not listed under the MMPA as strategic. Note, however, that other non-
anthropogenic factors (e.g. disease, decline is sea ice coverage) may 
influence overall stock abundance and population trends.
    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 1988b). 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.

[[Page 48687]]

    Ringed seals have at least two distinct types of subnivean lairs: 
haul-out lairs and birthing lairs (Smith and Stirling 1975). Haul-out 
lairs are typically single-chambered and offer protection from 
predators and cold weather. Birthing lairs are larger, multi-chambered 
areas that are used for pupping in addition to protection from 
predators. Ringed seal populations pup on both land-fast ice as well as 
stable pack ice. Lentfer (1972) found that ringed seals north of 
Barrow, Alaska (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 5-9 weeks 
during late winter and spring (Chapskii 1940; McLaren 1958; Smith and 
Stirling 1975). Snow depths of at least 50-65 centimeters (cm) are 
required for functional birth lairs (Kelly 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 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 being 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.

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 (2016) described 
generalized hearing ranges for these marine mammal hearing groups. 
Generalized hearing ranges were chosen based on the approximately 65 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. The functional groups and the associated 
frequencies are indicated below (note that these frequency ranges 
correspond to the range for the composite group, with the entire range 
not necessarily reflecting the capabilities of every species within 
that group):
     Low-frequency cetaceans (mysticetes): Generalized hearing 
is estimated to occur between approximately 7 Hz and 35 kHz, with best 
hearing estimated to be from 100 Hz to 8 kHz;
     Mid-frequency cetaceans (larger toothed whales, beaked 
whales, and most delphinids): Generalized hearing is estimated to occur 
between approximately 150 Hz and 160 kHz, with best hearing from 10 to 
less than 100 kHz;
     High-frequency cetaceans (porpoises, river dolphins, and 
members of the genera Kogia and Cephalorhynchus; including two members 
of the genus Lagenorhynchus, on the basis of recent echolocation data 
and genetic data): Generalized hearing is estimated to occur between 
approximately 275 Hz and 160 kHz;
     Pinnipeds in water; Phocidae (true seals): Generalized 
hearing is estimated to occur between approximately 50 Hz to 86 kHz, 
with best hearing between 1-50 kHz;
     Pinnipeds in water; Otariidae (eared seals): Generalized 
hearing is estimated to occur between 60 Hz and 39 kHz, with best 
hearing between 2-48 kHz.
    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., 2009b; Reichmuth and Holt, 
2013).
    For more detail concerning these groups and associated frequency 
ranges, please see NMFS (2016) for a review of

[[Page 48688]]

available information. As noted previously a single phocid species, 
ringed seal, has the reasonable potential to co-occur with the proposed 
survey activities.

Potential Effects of Specified Activities on Marine Mammals and Their 
Habitat

    This section includes a summary and discussion of the ways that 
components of the specified activity may impact marine mammals and 
their habitat. The ``Estimated Take by Incidental Harassment'' section 
later in this document will include 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 by Incidental 
Harassment'' 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 hertz (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 decibel (dB) scale. A dB is the ratio between a 
measured pressure (with sound) and a reference pressure (sound at a 
constant pressure, established by scientific standards). It is a 
logarithmic unit that accounts for large variations in amplitude; 
therefore, relatively small changes in dB ratings correspond to large 
changes in sound pressure. When referring to sound pressure levels 
(SPLs; the sound force per unit area), sound is referenced in the 
context of underwater sound pressure to 1 microPascal ([mu]Pa). One 
pascal is the pressure resulting from a force of one newton exerted 
over an area of one square meter. The source level (SL) represents the 
sound level at a distance of 1 m from the source (referenced to 1 
[mu]Pa). The received level is the sound level at the listener's 
position. Note that all underwater sound levels in this document are 
referenced to a pressure of 1 [micro]Pa and all airborne sound levels 
in this document are referenced to a pressure of 20 [micro]Pa.
    Root mean square (rms) is the quadratic mean sound pressure over 
the duration of an impulse. RMS is calculated by squaring all of the 
sound amplitudes, averaging the squares, and then taking the square 
root of the average (Urick 1983). Rms accounts for both positive and 
negative values; squaring the pressures makes all values positive so 
that they may be accounted for in the summation of pressure levels 
(Hastings and Popper 2005). This measurement is often used in the 
context of discussing behavioral effects, in part because behavioral 
effects, which often result from auditory cues, may be better expressed 
through averaged units than by peak pressures.
    When underwater objects vibrate or activity occurs, sound-pressure 
waves are created. These waves alternately compress and decompress the 
water as the sound wave travels. Underwater sound waves radiate in all 
directions away from the source (similar to ripples on the surface of a 
pond), except in cases where the source is directional. The 
compressions and decompressions associated with sound waves are 
detected as changes in pressure by aquatic life and man-made sound 
receptors such as hydrophones.
    Even in the absence of sound from the specified activity, the 
underwater environment is typically loud due to ambient sound. Ambient 
sound is defined as environmental background sound levels lacking a 
single source or point (Richardson et al.,1995), and the sound level of 
a region is defined by the total acoustical energy being generated by 
known and unknown sources. These sources may include physical (e.g., 
waves, earthquakes, ice, atmospheric sound), biological (e.g., sounds 
produced by marine mammals, fish, and invertebrates), and anthropogenic 
sound (e.g., vessels, dredging, aircraft, construction). A number of 
sources contribute to ambient sound, including the following 
(Richardson et al., 1995):
     Wind and waves: The complex interactions between wind and 
water surface, including processes such as breaking waves and wave-
induced bubble oscillations and cavitation, are a main source of 
naturally occurring ambient noise for frequencies between 200 Hz and 50 
kHz (Mitson, 1995). Under sea ice, noise generated by ice deformation 
and ice fracturing may be caused by thermal, wind, drift and current 
stresses (Roth et al., 2012).
     Precipitation: Sound from rain and hail impacting the 
water surface can become an important component of total noise at 
frequencies above 500 Hz, and possibly down to 100 Hz during quiet 
times. In the ice-covered study area, precipitation is unlikely to 
impact ambient sound.
     Biological: Marine mammals can contribute significantly to 
ambient noise levels, as can some fish and shrimp. The frequency band 
for biological contributions is from approximately 12 Hz to over 100 
kHz.
     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

[[Page 48689]]

distinctive signal that may affect marine mammals.
    Underwater sounds fall into one of two general sound types: Pulsed 
and non-pulsed (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.
    Pulsed 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. Pulsed 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 ICEX18 activities.
    Non-pulsed 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-pulsed sounds can be transient signals 
of short duration but without the essential properties of pulses (e.g., 
rapid rise time). Examples of non-pulsed sounds include those produced 
by vessels, aircraft, machinery operations such as drilling or 
dredging, vibratory pile driving, and active sonar systems such as 
those planned for use by the U.S. Navy as part of the proposed action. 
The duration of such sounds, as received at a distance, can be greatly 
extended in a highly reverberant environment.
    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 (TTS, in which case the animal's hearing 
threshold would recover over time (Southall et al., 2007). Repeated 
sound exposure that leads to TTS could cause PTS. In severe cases of 
PTS, there can be total or partial deafness, while in most cases the 
animal has an impaired ability to hear sounds in specific frequency 
ranges (Kryter 1985).
    When PTS occurs, there is physical damage to the sound receptors in 
the ear (i.e., tissue damage), whereas TTS represents primarily tissue 
fatigue and is reversible (Southall et al., 2007). In addition, other 
investigators have suggested that TTS is within the normal bounds of 
physiological variability and tolerance and does not represent physical 
injury (e.g., Ward, 1997). Therefore, NMFS does not consider TTS to 
constitute auditory injury.
    Relationships between TTS and PTS thresholds have not been studied 
in marine mammals--PTS data exists only for a single harbor seal 
(Kastak et al., 2008)--but are assumed to be similar to those in humans 
and other terrestrial mammals. PTS typically occurs at exposure levels 
at least several 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 thresholds are 15 to 20 dB higher 
than TTS cumulative sound exposure level 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

[[Page 48690]]

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 (Delphinapterus 
leucas), 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). 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 et al. (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 pulsed sound sources (typically seismic airguns or acoustic 
harassment devices) have been varied but often consist of avoidance 
behavior or other behavioral changes suggesting discomfort (Morton and 
Symonds 2002; see also Richardson et al., 1995; Nowacek et al., 2007).
    Available studies show wide variation in response to underwater 
sound; therefore, it is difficult to predict specifically how any given 
sound in a particular instance might affect marine mammals perceiving 
the signal. If a marine mammal does react briefly to an underwater 
sound by changing its behavior or moving a small distance, the impacts 
of the change are unlikely to be significant to the individual, let 
alone the stock or population. However, if a sound source displaces 
marine mammals from an important feeding or breeding area for a 
prolonged period, impacts on individuals and populations could be 
significant (e.g., Lusseau and Bejder 2007; Weilgart 2007; NRC 2003). 
However, there are broad categories of potential response, which we 
describe in greater detail here, that include alteration of dive 
behavior, alteration of foraging behavior, effects to breathing, 
interference with or alteration of vocalization, avoidance, and flight.
    Changes in dive behavior can vary widely, and may consist of 
increased or decreased dive times and surface intervals as well as 
changes in the rates of ascent and descent during a dive (e.g., Frankel 
and Clark 2000; Costa et al., 2003; Ng and Leung, 2003; Nowacek et al., 
2004; Goldbogen et al., 2013). Variations in dive behavior may reflect 
interruptions in biologically significant activities (e.g., foraging) 
or they may be of little biological significance. The impact of an 
alteration to dive behavior resulting from an acoustic exposure depends 
on what the animal is doing at the time of the exposure and the type 
and magnitude of the response.
    Disruption of feeding behavior can be difficult to correlate with 
anthropogenic sound exposure, so it is usually inferred by observed 
displacement from known foraging areas, the appearance of secondary 
indicators (e.g., bubble nets or sediment plumes), or changes in dive 
behavior. As for other types of behavioral response, the frequency, 
duration, and temporal pattern of signal presentation, as well as 
differences in species sensitivity, are likely contributing factors to 
differences in response in any given circumstance (e.g., Croll et al., 
2001; Nowacek et al.; 2004; Madsen et al., 2006; Yazvenko et al., 
2007). A determination of whether foraging disruptions incur fitness 
consequences would require information on or estimates of the energetic 
requirements of the affected individuals and the relationship between 
prey availability, foraging effort and success, and the life history 
stage of the animal.
    Variations in respiration naturally vary with different behaviors 
and alterations to breathing rate as a function of acoustic exposure 
can be expected to co-occur with other behavioral reactions, such as a 
flight response or an alteration in diving. However, respiration rates 
in and of themselves may be representative of annoyance or an acute 
stress response. Various studies have shown that respiration rates may 
either be unaffected or could increase, depending on the species and 
signal characteristics, again highlighting the importance in 
understanding species differences in the tolerance of underwater noise 
when determining the potential for impacts resulting from anthropogenic 
sound 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

[[Page 48691]]

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 action), 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 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 timeframe of the proposed action (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). Ringed seal 
lairs are typically used by individual seals (haul-out lairs) or by a 
mother with a pup (birthing lairs); large

[[Page 48692]]

lairs used by many seals for hauling out are rare (Smith and Stirling 
1975). Although the exact amount of transmission loss of sound 
traveling through ice and snow is unknown, it is clear that sound 
attenuation would occur due to the environment itself. Due to the 
significant attenuation of sound through the water (ice)/air interface, 
any potential sound entering a lair would be below the behavioral 
threshold and would not result in take. In-air (i.e., in the subnivean 
lair), the best hearing sensitivity for ringed seals has been 
documented between 3 and 5 kHz; at higher frequencies, the hearing 
threshold rapidly increases (Sills et al., 2015).
    If the 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 (Ursus maritimus) and Arctic foxes (Vulpes lagopus), although the 
type of sound would be novel to them. Responses of ringed seals to a 
variety of human-induced noises (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 (Kelly et al., 
1988). 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). Additionally, it is not unusual 
to find up to three birth lairs within 100 m of each other, probably 
made by the same female seal, as well as one or more haul-out lairs in 
the immediate area (Smith et al., 1991). If a ringed seal mother 
perceives the acoustic transmissions as a threat, the network of 
multiple birth and haul-out lairs allows the mother and pup to move to 
a new lair (Smith and Hammill 1981; Smith and Stirling 1975). However, 
the acoustic transmissions are unlike the low frequency sounds and 
vibrations felt from approaching predators. Additionally, the acoustic 
transmissions 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 transmissions (Elsner et al., 
1989; Wartzok et al., 1992a). It is anticipated that a ringed seal 
would be able to relocate to a different breathing hole relatively 
easily without impacting their normal behavior patterns.
    Stress responses--An animal's perception of a threat may be 
sufficient to trigger stress responses consisting of some combination 
of behavioral responses, autonomic nervous system responses, 
neuroendocrine responses, or immune responses (e.g., Seyle 1950; Moberg 
2000). In many cases, an animal's first and sometimes most economical 
(in terms of energetic costs) response is behavioral avoidance of the 
potential stressor. Autonomic nervous system responses to stress 
typically involve changes in heart rate, blood pressure, and 
gastrointestinal activity. These responses have a relatively short 
duration and may or may not have a significant long-term effect on an 
animal's fitness.
    Neuroendocrine stress responses often involve the hypothalamus-
pituitary-adrenal system. Virtually all neuroendocrine functions that 
are affected by stress--including immune competence, reproduction, 
metabolism, and behavior--are regulated by pituitary hormones. Stress-
induced changes in the secretion of pituitary hormones have been 
implicated in failed reproduction, altered metabolism, reduced immune 
competence, and behavioral disturbance (e.g., Moberg, 1987; Blecha, 
2000). Increases in the circulation of glucocorticoids are also equated 
with stress (Romano et al., 2004).
    The primary distinction between stress (which is adaptive and does 
not normally place an animal at risk) and ``distress'' is the cost of 
the response. During a stress response, an animal uses glycogen stores 
that can be quickly replenished once the stress is alleviated. In such 
circumstances, the cost of the stress response would not pose serious 
fitness consequences. However, when an animal does not have sufficient 
energy reserves to satisfy the energetic costs of a stress response, 
energy resources must be diverted from other functions. This state of 
distress will last until the animal replenishes its energetic reserves 
sufficient to restore normal function.
    Relationships between these physiological mechanisms, animal 
behavior, and the costs of stress responses are well-studied through 
controlled experiments and for both laboratory and free-ranging animals 
(e.g., Holberton et al., 1996; Hood et al., 1998; Jessop et al., 2003; 
Krausman et al., 2004; Lankford et al., 2005). Stress responses due to 
exposure to anthropogenic sounds or other stressors and their effects 
on marine mammals have also been reviewed (Fair and Becker, 2000; 
Romano et al., 2002b) and, more rarely, studied in wild populations 
(e.g., Romano et al., 2002a). These and other studies lead to a 
reasonable expectation that some marine mammals will experience 
physiological stress responses upon exposure to acoustic stressors and 
that it is possible that some of these would be classified as 
``distress.'' In addition, any animal experiencing TTS would likely 
also experience stress responses (NRC, 2003).
    Auditory masking--Sound can disrupt behavior through masking, or 
interfering with, an animal's ability to detect, recognize, or 
discriminate between acoustic signals of interest (e.g., those used for 
intraspecific communication and social interactions, prey detection, 
predator avoidance, navigation) (Richardson et al., 1995). Masking 
occurs when the receipt of a sound is interfered with by another 
coincident sound at similar frequencies and at similar or higher 
intensity, and may occur whether the sound is natural (e.g., snapping 
shrimp, wind, waves, precipitation) or anthropogenic (e.g., shipping, 
sonar, seismic exploration) in origin. The ability of a noise source to 
mask biologically important sounds depends on the characteristics of 
both the noise source and the signal of interest (e.g., signal-to-noise 
ratio, temporal variability, direction), in relation to each other and 
to an animal's hearing abilities (e.g., sensitivity, frequency range, 
critical ratios, frequency discrimination, directional discrimination, 
age or TTS hearing loss), and existing ambient noise and propagation 
conditions.
    Under certain circumstances, marine mammals experiencing 
significant masking could also be impaired from maximizing their 
performance fitness in survival and reproduction. Therefore, when the 
coincident (masking) sound is man-made, 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

[[Page 48693]]

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 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 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

[[Page 48694]]

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 ICEX18 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.
    ICEX18 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 ringed seals and 
ringed seal 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 seals or their populations.

Estimated Take

    This section provides an estimate of the number of incidental takes 
proposed for authorization through this IHA, which will inform 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 such 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. However, as 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.
    Described in the most basic way, we estimate take by considering: 
(1) Acoustic thresholds above which NMFS believes the best available 
science indicates marine mammals will be

[[Page 48695]]

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 recommends acoustic 
thresholds that identify the received level of underwater sound above 
which exposed marine mammals would be reasonably expected to incur PTS 
of some degree (equated to Level A harassment), TTS, or behavioral 
harassment (Level B harassment). The thresholds used to predict 
occurrences of each type of take are described below.
    Behavioral harassment--In coordination with NMFS, the Navy 
developed behavioral harassment thresholds to support Phase III 
environmental analyses and MMPA Letter of Authorization renewals for 
the Navy's testing and training military readiness activities; these 
behavioral harassment thresholds are being proposed for use here to 
evaluate the potential effects of this 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 Navy's behavioral response criteria for 
the Phase III 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 [micro]Pa @1m; 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% 
probability of response at 166 dB re 1 [mu]Pa. Additional details 
regarding the Phase III criteria may be found in the technical report, 
Criteria and Thresholds for U.S. Navy Acoustic and Explosive Effects 
Analysis (2017a) which may be found at: http://aftteis.com/Portals/3/docs/newdocs/Criteria%20and%20Thresholds_TR_Submittal_05262017.pdf. 
This technical report was as part of the Navy's Atlantic Fleet Training 
and Testing Draft Environmental Impact Statement/Overseas Environmental 
Impact Statement (EIS/OEIS) (Navy 2017b) which is located at: http://www.aftteis.com/. 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 (Technical 
Guidance, 2016) identifies dual criteria to assess auditory injury 
(Level A harassment) to five different marine mammal groups (based on 
hearing sensitivity) as a result of exposure to noise from two 
different types of sources (impulsive or non-impulsive).
    These thresholds were developed by compiling and synthesizing 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 2016 Technical Guidance, which may be 
accessed at: http://www.nmfs.noaa.gov/pr/acoustics/guidelines.htm.
    The 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

[[Page 48696]]

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 seal.......  Pinniped Dose       181 dB SEL          201 dB SEL
                                                       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 (Navy 2017a), 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 animals per km\2\ in the cold season (defined as December 
through May). 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.
    Note that while other surveys by Frost et al. (2004) and Bengston 
et al. (2005) provided ringed seal density estimates for areas near or 
within the Beaufort Sea, the Navy felt that those findings were not 
applicable to the proposed action area. Frost et al. (2004) only 
surveyed ringed seals out to 40 km from shore in the Beaufort Sea. A 
small portion of the surveys from Bengston et al. (2005) were out to a 
maximum extent of 185 km (100 nm) from shore, but the surveys were 
located within the Chukchi Sea, not the Beaufort Sea. Frost et al. 
(2004) also stated the highest densities of ringed seals were in water 
depths from 5-25 m (1-1.33 seals per km\2\). Lower densities were seen 
in waters greater than 35 m in depth (0-0.77 seals per km\2\).The 
proposed action area where acoustic transmissions would occur is 3,000 
to 4,000 m deep (International Bathymetric Chart of the Arctic Ocean 
2015), which makes the bathymetric nature of the areas different enough 
to be non-comparable. Furthermore, the ice camp is located on multi-
year ice and would not be located near the ice edge. Frost et al. 
(2004), and Bengston et al. (2005) both had a high percentage of fast 
or pack ice in their survey area which would not be present in the 
proposed action area. Additionally, there were areas of cracked ice 
that were part of the surveys. As previously noted, the ice camp needs 
to be situated in an area without cracks in the ice. After reviewing 
both Frost et al. (2004) and Bengston et al. (2005) NMFS agrees with 
the Navy that the density data from the RES model provides the most 
appropriate density values to be assessed for acoustic transmissions 
during ICEX18.
    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 active acoustic sources, 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

[[Page 48697]]

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 nonuniformly based on species-specific density, depth 
distribution, and group size information and animats record energy 
received at their location in the water column. A fully three-
dimensional environment is used for calculating sound propagation and 
animat exposure in NAEMO. Site-specific bathymetry, sound speed 
profiles, wind speed, and bottom properties are incorporated into the 
propagation modeling process. NAEMO calculates the likely propagation 
for various levels of energy (sound or pressure) resulting from each 
source used during the training 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 
acoustic effects on marine mammals.
    For non-impulsive sources, NAEMO calculates the sound pressure 
level (SPL) and SEL for each active emission over the entire duration 
of an event. These data are then processed using a bootstrapping 
routine to compute the number of animats exposed to SPL and SEL in 1 dB 
bins across all track iterations and population draws. (Bootstrapping 
is a type of resampling where large numbers of smaller samples of the 
same size are repeatedly drawn, with replacement, from a single 
original sample.) SEL is checked during this process to ensure that all 
animats are grouped in either an SPL or SEL category. A mean number of 
SPL and SEL exposures are computed for each 1 dB bin. The mean value is 
based on the number of animats exposed at that dB level from each track 
iteration and population draw. The behavioral risk function curve is 
applied to each 1 dB bin to compute the number of behaviorally exposed 
animats per bin. The number of behaviorally exposed animats per bin is 
summed to produce the total number of behavior exposures.
    Mean 1 dB bin SEL exposures are then summed to determine the number 
of PTS and TTS exposures. PTS exposures represent the cumulative number 
of animats exposed at or above the PTS threshold. The number of TTS 
exposures represents the cumulative number of animats exposed at or 
above the TTS threshold and below the PTS threshold. Animats exposed 
below the TTS threshold were grouped in the SPL category.
    Platforms such as a submarine 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. For analysis purposes, the Navy uses 
distance cutoffs, which is the maximum distance a Level B take would 
occur, beyond which the potential for significant behavioral responses 
is considered unlikely. For animals located beyond the range to 
effects, no significant behavioral responses are predicted. This is 
based on the Navy's Phase III environmental analysis (Navy 2017a). The 
Navy referenced Southall et al. (2007) who reported that pinnipeds do 
not exhibit strong reactions to SPLs up to 140 dB re 1 [micro]Pa from 
steady state (non-impulsive) sources. In some cases, pinnipeds tolerate 
impulsive exposures up to 180 dB re 1 [micro]Pa with limited avoidance 
noted (Southall et al., 2007), and no avoidance noted at distances as 
close as 42 m (Jacobs & Terhune 2002). While limited data exists on 
pinniped behavioral responses beyond 3 km in the water, the data that 
is available suggest that most pinnipeds likely do not exhibit 
significant behavioral reactions to sonar and other transducers beyond 
a few kilometers, independent of received levels of sound (Navy 2017a). 
Therefore, in the Navy's Phase III environmental analysis, the range to 
effects for pinnipeds is set at 5 km for moderate source level, single 
platform training and testing events and 10 km for all other events 
with multiple sonar platforms or sonar with source levels at or 
exceeding 215 dB re 1 [micro]Pa @1 m. Regardless of the source level, 
take beyond 10 km is not anticipated. These ranges are expected to 
reasonably contain the anticipated effects predicted by the behavioral 
response dose curve threshold reference above.
    For ICEX18 unclassified sources (i.e. Autonomous Reverberation 
Measurement System and MIT/Lincoln Labs continuous wave/chirp), the 
Navy models calculated a propagation loss measurement of 13.5 km from 
the source to the 120 dB re 1 [micro]Pa SPL isopleth; 1.5 km from the 
source to the 130 dB re 1 [micro]Pa SPL isopleth; and 400 m from the 
source to the 140 dB dB re 1 [micro]Pa SPL isopleth. Propagation loss 
measurements cannot be provided for classified sources. However, the 
ranges

[[Page 48698]]

in Table 4 provide realistic maximum distances over which the specific 
effects from the use of all active acoustic sources during the proposed 
action would be possible. Based on the information provided, NMFS is 
confident that the 10km zone safely encompasses the area in which Level 
B harassment can be expected from all active acoustic sources.

  Table 4--Range to Temporary Threshold Shift and Behavioral Effects in
                          the ICEX18 Study Area
------------------------------------------------------------------------
                                          Maximum range to Level B takes
                                                  cold season (m)
             Source/exercise             -------------------------------
                                            Behavioral          TTS
------------------------------------------------------------------------
Submarine Exercise......................          10,000             100
Autonomous Reverberation Measurement              10,000             <50
 System.................................
Massachusetts Institute of Technology/            10,000             <50
 Lincoln Labs Continuous Wave/chirp.....
Naval Research Laboratory Synthetic               10,000              90
 Aperture Sonar.........................
------------------------------------------------------------------------

    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.
    Utilizing the NAEMO model, the Navy projected that there will be 
1,665 behavioral Level B harassment takes and an additional 11 Level B 
takes due to TTS for a total of 1,676 takes of ringed seals. All takes 
would be underwater. Note that these quantitative results should be 
regarded as conservative estimates that are strongly influenced by 
limited marine mammal population data.

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 such 
activity, ``and other means of effecting the least practicable impact 
on such species or stock and its habitat, paying particular attention 
to rookeries, mating grounds, and areas of similar significance, and on 
the availability of such 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 such 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 
adverse 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, we carefully weigh two primary factors:
    (1) The manner in which, and the degree to which, implementation of 
the measure(s) is expected to reduce impacts to marine mammal species 
or stocks, their habitat, and their availability for subsistence uses 
(where relevant). This analysis will consider such things as the nature 
of the potential adverse impact (such as likelihood, scope, and range), 
the likelihood that the measure will be effective if implemented, and 
the likelihood of successful implementation; and
    (2) The practicability of the measures for applicant 
implementation. Practicability of implementation may consider such 
things as cost, impact on operations, and, in the case of a military 
readiness activity, specifically considers personnel safety, 
practicality of implementation, and impact on the effectiveness of the 
military readiness activity (16 U.S.C. 1371(a)(5)(A)(ii)).

Mitigation for Marine Mammals and Their Habitat

    The following general mitigation actions are proposed for ICEX18 to 
avoid any take of ringed seals on the ice floe:
     Camp deployment would begin in mid-February and would be 
completed by March 15, which is well before ringed seal pupping season 
begins. Pups are weaned and then mating occurs in April and May. 
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.
     Passengers 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.
     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 ICEX18.

[[Page 48699]]

    The following mitigation actions are proposed for ICEX18 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 prior to the 
initiation of exercise activities. If a marine mammal is detected, the 
submarine will delay active transmissions, including the launching of 
torpedoes, and not restart until after 15 minutes have passed with no 
marine mammal detections. If there are no animal detections, it is 
assumed that the vocalizing animal is no longer in the immediate area 
and is unlikely to be subject to harassment. Ramp up procedures will 
not be required as they would result in an unacceptable impact on 
readiness and on the realism of training.
    Based on our evaluation of the applicant's proposed measures, 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.

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 to 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); and
     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 has been created in direct 
response to Navy permitting requirements established in various MMPA 
Final Rules, ESA consultations, Biological Opinions, 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. ICEX18 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 ICEX18 
activity, the Navy will immediately halt the activity and report the 
incident consistent with the stranding and reporting protocol in the 
Atlantic Fleet Training and Testing stranding response plan (Navy 
2013). This approach is also consistent with other Navy documents 
including the Atlantic Fleet Training and Testing Environmental Impact 
Statement/Overseas Environmental Impact Statement.
    The Navy will provide NMFS with a draft exercise monitoring report 
within 90 days of the conclusion of the proposed 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

[[Page 48700]]

regulations (54 FR 40338; September 29, 1989), the impacts from other 
past and ongoing anthropogenic activities are incorporated into this 
analysis via their impacts on the environmental baseline (e.g., as 
reflected in the regulatory status of the species, population size and 
growth rate where known, ongoing sources of human-caused mortality, or 
ambient noise levels).
    Underwater acoustic transmissions associated with ICEX18, as 
outlined previously, have the potential to result in Level B harassment 
of ringed 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 ringed seals' likely behavioral response. 
NMFS anticipates that there will be 11 Level B takes due to TTS and 
1,665 behavioral Level B harassment takes, for a total of 1,676 ringed 
seal takes.
    Note that there are only 11 Level B takes due to TTS since the TTS 
range to effects is small at only 100 meters or less while the 
behavioral effects range is significantly larger extending up to 10 km. 
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. 
Though TTS may occur in up to 11 animals, the overall fitness of these 
individuals is unlikely to be affected and negative impacts to the 
entire stock 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 simply 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 [micro]Pa), have been 
shown to change their behavior by modifying diving activity and 
avoidance of the sound source (G[ouml]tz et al., 2010; Kvadsheim et 
al., 2010). Although a minor change to a behavior may occur as a result 
of exposure to the sound sources associated with the proposed 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 proposed 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 four weeks. The Autonomous 
Reverberation Measurement System would be active for up to 30 days; the 
vertical line array would be active for up to four hours per day for no 
more than eight days, and; the unmanned underwater vehicle used for the 
deployment of a synthetic aperture source would transmit for 24 hours 
per day for up to eight days.
    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 the area of disturbance, temporarily 
impacting marine mammals' foraging opportunities, this would encompass 
a relatively small area of habitat leaving large areas of existing fish 
and marine mammal foraging habitat unaffected. As such, the impacts to 
marine mammal habitat are not expected to cause significant or long-
term negative consequences.
    For on-ice activity, neither take nor mortality of seals are 
expected due to 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-meter avoidance distance from any arctic animals. Implementation of 
these measures should ensure that ringed seal lairs are not crushed or 
damaged during ICEX18 activities.
    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 haul-out lairs 
would allow the mother and pup to move to a new lair.
    The estimated population of the Alaska stock of ringed seals in the 
Bering Sea is 170,000 animals (Muto et al., 2016). The estimated 
population in the Alaska Chukchi and Beaufort Seas is at least 300,000 
ringed seals, which is likely an underestimate since the Beaufort Sea 
surveys were limited to within 40 km from shore (Kelly et al., 2010). 
Given these population estimates, only a limited percent of the stock 
affected would be taken (i.e. between 0.98 and 0.56 percent).
    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;
     A small percentage (<1 percent) of the Alaska stock of 
ringed seals would be subject to Level B harassment;
     TTS is expected to affect only a limited number of 
animals;
     There will be no loss or modification of ringed seal prey 
or habitat;
     Physical impacts to ringed seal subnivean lairs will be 
avoided; and
     Ice camp activities would not affect 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 48701]]

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 100-200 nmi seaward of known subsistence use 
areas. Harvest locations for ringed seals extend up to 80 nmi from 
shore during the summer months while winter harvest of ringed seals 
typically occurs closer to shore. 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 ESA of 1973 (16 U.S.C. 1531 et seq.) 
requires that each Federal agency insure that any action it authorizes, 
funds, or carries out is not likely to jeopardize the continued 
existence of any endangered or threatened species or result in the 
destruction or adverse modification of designated critical habitat. To 
ensure ESA compliance for the issuance of IHAs, NMFS consults 
internally with our ESA Interagency Cooperation Division whenever we 
propose to authorize take for endangered or threatened species.
    No incidental take of ESA-listed species is proposed for 
authorization or expected to result from this activity. Therefore, NMFS 
has determined that formal consultation under section 7 of the ESA is 
not required for this action.

Proposed Authorization

    As a result of these preliminary determinations, NMFS proposes to 
issue an IHA to the Navy for conducting submarine training and testing 
provided the previously mentioned mitigation, monitoring, and reporting 
requirements are incorporated. This section contains a draft of the IHA 
itself. The wording contained in this section is proposed for inclusion 
in the IHA (if issued).
    1. This Authorization is valid from February 1, 2018 through May 1, 
2018.
    2. This Authorization is valid only for activities associated with 
submarine training and testing in the Beaufort Sea and Arctic Ocean.
    3. General Conditions.
    (a) A copy of this IHA must be in the possession of the Navy, its 
designees, and work crew personnel operating under the authority of 
this IHA.
    (b) The number of animals and species authorized for taking by 
Level B harassment is 1,676 ringed seals.
    4. Prohibitions.
    (a) The taking, by incidental harassment only, is limited to the 
species and number listed under condition 3(b). The taking by death of 
these species or the taking by harassment, injury or death of any other 
species of marine mammal is prohibited and may result in the 
modification, suspension, or revocation of this Authorization.
    5. Mitigation Measures.
    The holder of this Authorization is required to implement the 
following mitigation measures.
    (a) Shutdown Measures.
    (i) The Navy shall implement shutdown measures if a marine mammal 
is detected by submarines via passive acoustics during use of active 
sonar transmissions from submarines and torpedoes.
    (ii) The Navy shall not restart acoustic transmissions until after 
15 minutes have passed with no marine mammal detections.
    (b) The Navy shall avoid on-ice take by implementing the following:
    (i) Foot and snowmobile movement shall avoid pressure ridges;
    (ii) The ice camp, including runway, shall be built on multi-year 
ice without pressure ridges;
    (iii) Snowmobiles shall follow established routes;
    (iv) Camp deployment shall be gradual with activity increasing over 
the first five days and shall be completed by March 15, 2018.
    (vi) Implementation of 100-meter avoidance distance of all marine 
mammals.
    6. Reporting.
    The holder of this Authorization is required to:
    (a) Submit a draft exercise monitoring report within 90 days of the 
completion of proposed training and testing activities.
    (b) The draft exercise monitoring report will include data 
regarding sonar use and any marine mammal sightings or detection. It 
will also include information on the number of sonar-related shutdowns 
recorded.
    (c) 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.
    (d) Reporting injured or dead marine mammals:
    (i) In the unanticipated event that the specified activity clearly 
causes the take of a marine mammal in a manner prohibited by this IHA, 
such as an injury (Level A harassment), serious injury, or mortality, 
the Navy shall immediately cease the specified activities and report 
the incident to the Office of Protected Resources, NMFS, and the Alaska 
Regional Stranding Coordinator, NMFS. The Navy shall adhere to 
protocols outlined in the Stranding Response Plan for Atlantic Fleet 
Training and Testing (AFTT) Study Area (November 2013).
    7. This Authorization may be modified, suspended or withdrawn if 
the holder fails to abide by the conditions prescribed herein, or if 
NMFS determines the authorized taking is having more than a negligible 
impact on the species or stock of affected marine mammals.

Request for Public Comments

    We request comment on our analyses, the draft authorization, and 
any other aspect of this Notice of Proposed IHA for the Navy's proposed 
ICEX18 training and testing activities. Please include with your 
comments any supporting data or literature citations to help inform our 
final decision on the request for MMPA authorization.

    Dated: October 13, 2017.
Catherine Marzin,
Acting Deputy Director, Office of Protected Resources, National Marine 
Fisheries Service.
[FR Doc. 2017-22637 Filed 10-18-17; 8:45 am]
 BILLING CODE 3510-22-P