[Federal Register Volume 86, Number 102 (Friday, May 28, 2021)]
[Notices]
[Pages 28787-28809]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2021-11339]



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DEPARTMENT OF COMMERCE

National Oceanic and Atmospheric Administration

[RTID 0648-XB015]


Takes of Marine Mammals Incidental to Specified Activities; 
Taking Marine Mammals Incidental to a Geophysical Survey in the Arctic 
Ocean

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

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

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SUMMARY: NMFS has received a request from the University of Alaska 
Geophysics Institute (UAGI) for authorization to take marine mammals 
incidental to a geophysical survey in the Arctic Ocean. The proposed 
survey would be funded by the National Science Foundation (NSF). 
Pursuant to the Marine Mammal Protection Act (MMPA), NMFS is requesting 
comments on its proposal to issue an incidental harassment 
authorization (IHA) to incidentally take marine mammals during the 
specified activities. NMFS is also requesting comments on a possible 
one-time, one-year renewal that could be issued under certain 
circumstances and if all requirements are met, as described in Request 
for Public Comments at the end of this notice. NMFS will consider 
public comments prior to making any final decision on the issuance of 
the requested MMPA authorizations and agency responses will be 
summarized in the final notice of our decision.

DATES: Comments and information must be received no later than June 28, 
2021.

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

FOR FURTHER INFORMATION CONTACT: Kim Corcoran, Office of Protected 
Resources, NMFS, (301) 427-8401. Electronic copies of the application 
and supporting documents, as well as a list of the references cited in 
this document, may be obtained online at: https://www.fisheries.noaa.gov/permit/incidental-take-authorizations-under-
marine-mammal-protection-act. In case of problems accessing these 
documents, or for anyone who is unable to comment via electronic mail, 
please call the contact listed above.

SUPPLEMENTARY INFORMATION:

Background

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

National Environmental Policy Act

    To comply with the National Environmental Policy Act of 1969 (NEPA; 
42 U.S.C. 4321 et seq.) and NOAA Administrative Order (NAO) 216-6A, 
NMFS must review our proposed action (i.e., the issuance of an IHA) 
with respect to potential impacts on the human environment.
    NMFS plans to adopt the NSF's Environmental Assessment (EA), as we 
have preliminarily determined that it includes adequate information 
analyzing the effects on the human environment of issuing the IHA. 
NSF's EA is available at www.nsf.gov/geo/oce/envcomp/.
    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 February 12, 2021, NMFS received a request from UAGI for an IHA 
to take marine mammals incidental to a geophysical survey in the Arctic 
Ocean. The application was deemed adequate and complete on April 6, 
2021. UAGI's request is for take of 13 species of marine mammals, by 
Level B harassment only. No Level A harassment is anticipated. Neither 
UAGI nor NMFS expects serious injury or mortality to result from this 
activity. Therefore, an IHA is appropriate.

Description of Proposed Activity

Overview

    Researchers at UAGI, with funding from NSF, propose to conduct a 
seismic survey from the Research Vessel (R/V) Sikuliaq in the Arctic 
Ocean to document the structure and stratigraphy of the Chukchi 
Borderland and adjacent Canada basin. The proposed activity is planned 
to take place in late summer 2021 (August/September) with a total of 30 
days of data acquisition. The survey would include both high energy and 
low energy components. High-energy ocean bottom seismometer (OBS) 
refraction surveys will use a 6-airgun, 3120 cubic inches (in\3\) array 
and consist of ~12 percent of total survey effort (henceforth referred 
to as high-energy survey). Low-energy multi-channel seismic (MCS) 
reflection surveys will use a 2-airgun array with a total discharge 
volume of 1040 in\3\ and consist of ~88 percent of total survey effort 
(henceforth referred to as low-energy survey).

Dates and Duration

    The proposed activity will occur between August and September, 
2021. The activity is planned to occur for 45 days total, with ~30 days 
dedicated to seismic data acquisition (with 24-hours

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a day operations), ~8 days devoted to transit and 7 days used for 
equipment deployment and recovery.

Specific Geographic Region

    The proposed surveys would occur within ~73.5-81.0[deg]N, ~139.5-
168[deg]W (>=300 kilometer (km) north of Utqia[gdot]vik). 
Representative survey track lines can be seen in Figure 1. Some 
deviation in track lines, including the order of survey operations, 
could be necessary for reasons such as science drivers, poor data 
quality, inclement weather, or mechanical issues with the research 
vessel and/or equipment. Thus, the track lines could occur anywhere 
within the coordinates noted above and within the study area. Four 
percent of the surveys will occur within the U.S. Exclusive Economic 
Zone (EEZ) with the remaining part of the survey occurring beyond the 
EEZ. The activity will take place in depths ranging from 200-4,000 
meters (m). The R/V Sikuliaq would likely leave and return to Nome, AK.
    The low-energy survey activity will begin ~300 km from the Alaskan 
coastline (North of Utqiagvik) and extend ~800 km north from the 
initial survey site (i.e., the survey would occur ~300-1,100 km from 
the Alaska coastline). The high-energy survey activity will only occur 
~530 km from the coastline and occur only in the northeastern part of 
the survey area (See Figure 1). Eighty percent of the total survey will 
occur in deep waters (>1,000m) with the remainder of the survey 
occurring in intermediate depth waters (100-1,000 m); no surveying will 
occur in waters <100 m deep. All high-energy surveys (680 km total) 
will occur in deep waters, while 67 percent of low-energy surveys will 
occur in deep waters (3,981 km) with the remainder occurring in 
intermediate depth waters (1,189 km or 23 percent).
BILLING CODE 3510-22-P

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[GRAPHIC] [TIFF OMITTED] TN28MY21.002

BILLING CODE 3510-22-C

Detailed Description of Specific Activity

    The proposed study would use low-energy two-dimensional (2-D) 
seismic surveying to document the history, structure, and stratigraphy 
of the Chukchi Borderland and adjacent Canada Basin, and use high-
energy seismic refraction data in the Canada Basin to characterize the 
deep crustal structure associated with an extinct mid-ocean ridge in 
the central basin.
    The procedures to be used for the proposed marine geophysical 
survey would include conventional seismic methodology. The survey would 
involve one source vessel, R/V Sikuliaq, which has a cruising speed of 
10 knots (kt), and would tow an array of 6 airguns (520 in\3\ (8,521.27 
cm\3\) each) and a total possible discharge volume of ~3,120 in\3\ 
during high-energy surveys. During low-energy reflection surveys, a 2-
airgun array (at 520 in\3\ each) would be used with a total discharge 
volume of 1,040 in\3\. Both arrays will be towed at a depth of 9m. 
During low-energy surveys (~88 percent of total line km), a 1-3 km long 
hydrophone streamer (depending on ice conditions) would be employed as 
the receiving system, and high-energy surveys (~12 percent of total 
line km) would employ nine OBSs as the receiving system. As the airgun 
arrays

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are towed along the survey lines, the OBSs would receive and store the 
returning acoustic signals internally for later analysis, and the 
hydrophone streamer would transfer the data to the on-board processing 
system. The airguns would fire at a shot interval of 35 m (~15 seconds 
(s)) during the low-energy surveys and at a 139-m (~60 s) interval 
during the high-energy refraction surveys. The airguns would operate at 
a firing pressure of 2,540 pounds per square inch (psi).
    In addition to the aforementioned planned survey lines, some lines, 
as indicated in Figure 1, will be surveyed twice: Once for low-energy 
reflection and again for high energy refraction. These surveys would 
take place near the end of operations in the northeastern part of the 
survey area (Fig. 1); however, the location of these surveys could 
shift slightly to ensure one survey occurs over the extinct ridge axis 
and the other on hyper-extended continental crust. A total of nine OBSs 
would be deployed twice for a total of 18 deployment sites during high 
energy survey effort. Nine OBSs would be deployed during low-energy 
surveying, then high-energy refraction data would be acquired along 
these same lines, followed by retrieval of the OBS equipment, before R/
V Sikuliaq would travel to the next site to deploy all nine OBSs again. 
Approximately 5,850 total line km would be surveyed, including 5,170 km 
of low-energy surveys, and 680 km of high-energy surveys. There could 
be additional seismic operations associated with turns, airgun testing, 
and repeat coverage of any areas where initial data quality is sub-
standard. As a result, a 25 percent buffer has been added in the form 
of operational days, which is equivalent to adding 25 percent to the 
proposed line km to be surveyed. Most of the survey (80 percent) would 
occur in deep water (>1,000 m), and 20 percent would occur in 
intermediate water (100-1,000 m deep); there would be no effort in 
shallow water <100 m deep.
    In addition to the operations of the airgun array, a multibeam 
echosounder (MBES), a sub-bottom profiler (SBP), and an Acoustic 
Doppler Current Profiler (ADCP) would be operated from R/V Sikuliaq 
continuously during the seismic surveys, but not during transit to and 
from the survey area. Take of marine mammals is not expected to occur 
incidental to use of the MBES, SBP, or ADCP because they will be 
operated only during seismic acquisition, and it is assumed that, 
during simultaneous operations of the airgun array and the other 
sources, any marine mammals close enough to be affected by the MBES, 
SBP, and ADCP would already be affected by the airguns. However, 
whether or not the airguns are operating simultaneously with the other 
sources, given their characteristics (e.g., narrow downward-directed 
beam), marine mammals would experience no more than one or two brief 
ping exposures, if any exposure were to occur.
    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 the potentially affected species. 
Additional information regarding population trends and threats may be 
found in NMFS's Stock Assessment Reports (SARs; https://www.fisheries.noaa. gov/national/marine-mammal-protection/marine-
mammal-stock-assessments) and more general information about these 
species (e.g., physical and behavioral descriptions) may be found on 
NMFS's website (https://www.fisheries.noaa.gov/find-species). 
Additional information may be found in the Aerial Survey of Arctic 
Marine Mammals (ASAMM) reports, which are available online at https://www.fisheries.noaa.gov/alaska/marine-mammal-protection/aerial-surveys-
arctic-marine-mammals.
    Table 1 lists all species or stocks for which take is expected and 
proposed to be authorized for this action, and summarizes information 
related to the population or stock, including regulatory status under 
the MMPA and Endangered Species Act (ESA) and potential biological 
removal (PBR), where known. For taxonomy, we follow Committee on 
Taxonomy (2020). 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.
    Marine mammal abundance estimates presented in this document 
represent the total number of individuals that make up a given stock or 
the total number estimated within a particular study or survey area. 
NMFS's stock abundance estimates for most species represent the total 
estimate of individuals within the geographic area, if known, that 
comprises that stock. For most species, stock abundance estimates are 
based on sightings within the U.S. EEZ, however for some species, this 
geographic area may extend beyond U.S. waters. Other species may use 
survey abundance estimates. Survey abundance (as compared to stock or 
species abundance) is the total number of individuals estimated within 
the survey area, which may or may not align completely with a stock's 
geographic range as defined in the SARs. These surveys may also extend 
beyond U.S. waters. In this case, the proposed survey area outside of 
the U.S. EEZ does not necessarily overlap with the ranges for stocks 
managed by NMFS. However, we assume that individuals of these species 
that may be encountered during the survey would be part of those 
stocks. Additionally, six species listed in Table 1 indicate Unknown 
abundance estimates. This may be due to outdated data and population 
estimates or data is not representative of the entire stock.
    All managed stocks in this region are assessed in NMFS's U.S. 
Alaska and Pacific SARs (e.g., Muto et al., 2020, Carretta et al., 
2020). All values presented in Table 1 are the most recent available at 
the time of publication and are available in the 2019 SARs (Muto et 
al., 2020, Carretta et al., 2020) and draft 2020 SARs (available online 
at: https://www.fisheries.noaa.gov/national/marine-mammal-protection/
draft-marine-mammal-stock-assessment-reports).
    In addition, the Pacific walrus (Odobenus rosmarus divergens) and 
the Polar bear (Ursus maritimus) may be found in the Arctic. However, 
Pacific walruses and Polar bears are managed by the U.S. Fish and 
Wildlife Service and are not considered further in this document.

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                                              Table 1--Marine Mammals Expected To Occur in the Survey Area
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                                                                                      ESA/MMPA status;   Stock abundance (CV,
            Common name                  Scientific name              Stock           strategic (Y/N)     Nmin, most recent       PBR       Annual M/SI
                                                                                            \1\         abundance survey) \2\                   \3\
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                          Order Cetartiodactyla--Cetacea--Superfamily Mysticeti (baleen whales)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Family Eschrichtiidae:
    Gray whale.....................  Eschrichtius robustus.  Eastern N Pacific.....  -, -, N            26,960 (0.05, 25,849,        801             131
                                                                                                         2016).
Family Balaenidae:
    Bowhead whale..................  Balaena mysticetus....  Western Arctic........  E, D, Y            16,820                       161              56
                                                                                                         (0.052,16,100,2011).
Family Balaenopteridae (rorquals):
    Fin whale......................  Balaenoptera physalus.  Northeast Pacific \4\   E, D, Y            Unknown..............        UND             0.6
                                                              *.
    Humpback whale.................  Megaptera novaeangliae  Western N Pacific *...  E, D, Y            1,107 (0.3, 865,               3             2.8
                                                                                                         2006).
    Minke whale....................  Balaenoptera            Alaska \4\ *..........  -, -, N            Unknown..............        UND               0
                                      acutorostrata.
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                            Superfamily Odontoceti (toothed whales, dolphins, and porpoises)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Family Delphinidae:
    Beluga whale...................  Delphinapterus leucas.  Beaufort Sea \4\......  -, -, N            39,258 (0.229, N/A.          UND             102
                                                                                                         1992).
                                                             Eastern Chukchi.......  -, -, N            13,305 (0.51, 8,875,         178              55
                                                                                                         2017).
    Killer whale...................  Orcinus orca..........  Alaska resident.......  -, -, N            2,347 c (N/A, 2347,           24               1
                                                                                                         2012).
    Narwhal........................  Monodon Monoceros.....  Unidentified \4\ *....  -, -, N            Unknown..............        UND               0
Family Phocoenidae (porpoises):
    Harbor Porpoise................  Phocoena phocoena.....  Bering Sea \4\ *......  -, -, Y            Unknown..............        UND             0.4
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                                                         Order Carnivora--Superfamily Pinnipedia
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Family Phocidae (earless seals):
    Bearded Seal...................  Erignathus barbatus...  Beringia \4\ *........  T, D, Y            Unknown..............        UND           6,709
    Ribbon Seal....................  Histriophoca fasciata.  Unidentified *........  -, -, N            184,687 (see SAR,          9,785             163
                                                                                                         163,086, 2013).
    Ringed Seal....................  Pusa hispida..........  Arctic................  T, D, Y            Unknown..............      5,100           6,459
    Spotted Seal...................  Phoca largha..........  Bering................  -, -, N            461,625 (see SAR,         25,394           5,254
                                                                                                         423,237, 2013).
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* Stocks marked with an asterisk are addressed in further detail in the text below.
\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. For most stocks of killer whales, the abundance values represent direct counts of individually
  identifiable animals; therefore there is only a single abundance estimate with no associated CV. For certain stocks of pinnipeds, abundance estimates
  are based upon observations of animals (often pups) ashore multiplied by some correction factor derived from knowledge of the species' (or similar
  species') life history to arrive at a best abundance estimate; therefore, there is no associated CV. In these cases, the minimum abundance may
  represent actual counts of all animals ashore.
\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).
\4\ Abundance estimates for these stocks are not considered current. PBR is therefore considered undetermined for these stocks, as there is no current
  minimum abundance estimate for use in calculation. We nevertheless present the most recent abundance estimates, as these present the best available
  information for use in this document.

    As indicated above, all 13 species (with 14 managed stocks) in 
Table 1 could temporally and spatially co-occur with the activity to 
the degree that take is reasonably likely to occur, and we have 
proposed authorizing it. All species that could potentially occur in 
the proposed survey areas are included in Table 4 of the IHA 
application.
    Beluga whales and ringed seals are the marine mammal species most 
likely to be encountered during this survey, with bowhead whales and 
bearded seals also having a higher likelihood of co-occuring in the 
survey area over the other proposed species in Table 1. However, these 
four species (beluga whales, ringed seals, bowhead whales and bearded 
seals) are most common within 100 km of shore, whereas the proposed 
survey would occur no closer than 300 km from shore, with most effort 
further north. Thus, despite their prevalence in Arctic waters north of 
Alaska, we expect there to be a low likelihood of encountering even 
beluga whales, ringed seals, bowhead whales and bearded seals during 
the proposed survey given the proposed activity's distance from shore.
    Humpbacks, fin and minke whales have rarely been observed as far 
north in the Arctic Ocean as the planned survey location but have been 
spotted on rare occasions in areas coinciding with the lower latitudes 
of the proposed survey area during previous aerial surveys. Similar 
sightings during the proposed activity are expected to be limited 
during the proposed survey as the majority of the proposed survey area 
occurs in higher latitudes and outside typical migratory patterns for 
these species (Brueggeman, 2009; Haley et al. 2010; Clarke et al., 
2011; Schuck et al., 2017). However, Brower et al. (2018) suggest that 
sightings of these sub-Arctic species are increasing in the eastern 
Chukchi Sea as of recent years due to climate change. Killer whales, 
gray whales, humpback whales, fin whales, minke whales and harbor 
porpoises are minimally sighted in the Chukchi Sea based on ASAMM data 
and are primarily coastal species, however recent monitoring activities 
in the Chukchi and Beaufort seas during industry seismic surveys also 
suggests that some of these species may be increasing in numbers in the 
Arctic but are still expected to be south of the proposed survey area 
(Funk et al., 2010). Additionally, there are scattered records of 
narwhal in Alaskan waters, where the species is considered to be 
extralimital. However, we do not expect the species to be encountered 
far north in the proposed survey area (Reeves et al., 2002). Although 
we do not expect

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the proposed survey area to coincide with expected ranges of the 
species described in this paragraph, takes equivalent to the average 
group size for the species are proposed for authorization at the 
applicant's request as a precaution due to the potential that they 
could be encountered.
    Prior to 2016, humpback whales were listed under the ESA as an 
endangered species worldwide. Following a 2015 global status review 
(Bettridge et al., 2015), NMFS delineated 14 distinct population 
segments (DPS) with different listing statuses (81 FR 62259; September 
8, 2016) pursuant to the ESA. The DPSs that occur in U.S. waters do not 
necessarily equate to the existing stocks designated under the MMPA.
    Within Alaska waters, four humpback whale DPSs may occur: The 
Western North Pacific (WNP) DPS (endangered), Hawaii DPS (not listed), 
Mexico DPS (threatened), and Central America DPS (endangered). 
According to Wade (2017), in the Bering, Chukchi, and Beaufort Seas, 
encountered whales are most likely to be from the Hawaii DPS (86.8 
percent), but could be from the Mexico DPS (11.0 percent) or WNP DPS 
(2.1 percent). Note that these probabilities reflect the upper limit of 
the 95 percent confidence interval of the probability of occurrence; 
therefore, numbers may not sum to 100 percent for a given area. Because 
this project occurs north of the Chukchi and Beaufort Sea and in the 
Arctic, we hypothesize that the Western North Pacific Stock of humpback 
whales will overlap with the proposed survey area, and thus include 
animals from the WNP DPS, Hawaii DPS and Mexico DPS as previously 
mentioned.
    At this time, there is no comprehensive abundance estimate 
available in the SARs for the Alaska stock of minke whales. However, 
the International Whaling Commission (IWC) reports an abundance 
estimate of 20,000 minke whales in the North Pacific (North West 
Pacific and Okhotsk Sea) (2003), which is the figure used for analysis. 
This estimate encompasses the distribution of minke whales throughout 
the North Pacfic extending to 80 degrees North. 20,000 is the most 
recent abundance estimate available for minke whales in the North 
Pacific provided by IWC. In 2017, the IWC Scientific Committee 
established a new group to review all abundance estimates and ensure 
quality and consistency across estimates used by IWC. According to the 
IWC website and the criteria established by this group, the 20,000 
whale estimate in the North Pacific from 2003 is considered to be the 
`best' estimate at this time.
    Similarly, although a comprehensive abundance estimate is not 
available for the northeast Pacific stock of fin whales, provisional 
estimates representing portions of the range are available. The same 
2010 survey of the eastern Bering sea shelf provided an estimate of 
1,061 (CV = 0.38) fin whales (Friday et al. 2013). The estimate is not 
corrected for missed animals, but is expected to be robust as previous 
studies have shown that only small correction factors are needed for 
fin whales (Barlow, 1995). Zerbini et al. (2006) produced an estimate 
of 1,652 (95 percent Confidence Interval (CI): 1,142-2,389) fin whales 
for the area described above.
    Narwhals are found year-round in the Arctic but rarely occur in the 
western Arctic, in areas including the Bering, Chukchi, and Beaufort 
Seas (COSEWIC, 2004). There are three populations of narwhals 
recognized internationally based on geographic separation, which 
include the Baffin Bay population, Hudson Bay population, and the East 
Greenland population. Currently, very little is known about these 
populations. The primary source for data and knowledge of narwhals in 
Alaska waters is local observations and traditional ecological 
knowledge dating back to the 1800s (Noogwook et al., 2007). Individual 
sightings have occurred in Russian waters of the northern Chukchi Sea 
(Yablokov and Bel'kovich, 1968; Reeves and Tracey, 1980). Additionally, 
Alaska Native hunters recorded seven sightings of narwhals between 1989 
and 2008, four of which consisted of mixed groups of narwhals and 
belugas (George and Suydam, unpublished manuscript). Records of 
narwhals in the Beaufort, Chukchi, and Bering Seas are hypothesized to 
be whales from the Baffin Bay population, migrating into the Canadian 
Arctic as ice conditions permit (COSEWIC, 2004). At this time, there 
are no reliable estimates of abundance for narwhals in Alaskan waters.
    Based on previous industry-sponsored monitoring in the Beaufort 
Sea, harbor porpoises regularly occur in both the Chukchi and Beaufort 
Seas (Funk et al., 2011). They have been sighted during several seismic 
surveys, both nearshore and offshore, between July and November (Funk 
et al., 2010, 2011; Reiser et al., 2011; Aerts et al., 2013). After 
gray whales and bowhead whales, they are the most frequently sighted 
cetacean in the Chukchi Sea (Funk et al., 2011; Reiser et al., 2011). 
Shipboard visual line-transect surveys occurred biannually from 1999 to 
2010, resulting in harbor porpoise abundance estimates for each survey. 
These surveys demonstrate the distribution of harbor porpoises 
throughout the Chukchi and Beaufort Seas but are not reliable for 
estimating abundance estimates in this region.
    Bearded seals are widely distributed throughout the summer and 
fall, following ice coverage northward, while juvenile seals remain 
near the coasts of the Bering and Chukchi Seas (Burns, 1967, 1981; 
Heptner et al., 1976; Nelson, 1981; Cameron et al., 2018). At this 
time, there is no reliable population estimate available for the entire 
Alaska stock of bearded seals. Recent aerial abundance surveys (Conn et 
al., 2014) used a sub-sample of data collected in the U.S. portion of 
the Bering Sea to calculate a partial abundance estimate of 301,836 
seals (95 percent CI: 238,195-371,147). Future studies plan to combine 
spring survey results of the Chukchi Sea and Beaufort Sea.
    Similarly, ringed seals also lack a reliable population estimate 
for the entire stock. Conn et al. (2014) calculated an abundance 
estimate of 171,418 ringed seals (95 percent CI: 141,588-201,090) using 
a sub-sample of data collected from the U.S. portion of the Bering Sea 
in 2012. Researchers plan to combine these results with those from 
spring surveys of the Chukchi and Beaufort Seas once complete. During 
the summer months, ringed seals forage along ice edges or in open water 
areas of high productivity and have been observed in the northern 
Beaufort Sea during summer months (Harwood and Stirling, 1992; Freitas 
et al., 2008; Kelly et al., 2010b; Harwood et al., 2015). This open 
water movement becomes limited with the onset of ice in the fall 
forcing the seals to move west and south as ice packs advance, 
dispersing the animals throughout the Chukchi and Bering Seas, with 
only a portion remaining in the Beaufort Sea (Frost and Lowry, 1984; 
Crawford et al., 2012; Harwood et al., 2012).
    In addition to ringed and bearded seals, other pinniped species 
that could be encountered during the proposed survey include the ribbon 
seal and spotted seal. The ribbon seal is uncommon in the Chukchi Sea, 
and there are few sightings in the Beaufort Sea. From late March to 
early May, ribbon seals inhabit the Bering Sea ice front. They are most 
abundant in the northern part of the ice front in the central and 
western parts of the Bering Sea. As the ice recedes in May to mid-July, 
the seals move farther north in the Bering Sea, where they haul out on 
the receding ice edge and remnant ice. Spotted seals are more abundant 
in the Chukchi Sea and occur in small numbers in the Beaufort Sea. As 
the ice melts, seals become more concentrated,

[[Page 28793]]

with part of the Bering Sea population moving to the Bering Strait and 
the southern part of the Chukchi Sea. The distribution of spotted seals 
is seasonally related to specific life-history events that can be 
broadly divided into two periods: Late-fall through spring, when 
whelping, nursing, breeding, and molting occur in association with the 
presence of sea ice on which the seals haul out, and summer through 
fall when seasonal sea ice has melted and most spotted seals use land 
for hauling out. Satellite-tagging studies showed that seals tagged in 
the northeastern Chukchi Sea moved south in October and passed through 
the Bering Strait in November. Seals overwintered in the Bering Sea 
along the ice edge and made east-west movements along the edge. In 
summer and fall, spotted seals use coastal haul-out sites regularly and 
may be found as far north as 69-72[deg] N in the Chukchi and Beaufort 
seas. Neither of these species would likely be encountered during the 
proposed activity other than perhaps during transit periods to or from 
the survey area. Although their encounters this far north in the Arctic 
are rare, authorization of take has been proposed at the request of the 
applicant. Clarke et al. (2015) described Biological Important Areas 
(BIAs) for cetaceans in the Arctic. BIAs were delineated for two baleen 
whale species, bowhead whales and gray whales, and one toothed whale, 
the beluga whale. The proposed UAGI survey areas do not coincide with 
any of the three Arctic BIAs.

Unusual Mortality Events (UME)

    A UME is defined under the MMPA as ``a stranding that is 
unexpected; involves a significant die-off of any marine mammal 
population; and demands immediate response.'' For more information on 
UMEs, please visit: www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-unusual-mortality-events. Currently recognized 
UMEs in Alaska involving species under NMFS' jurisdiction include those 
affecting ice seals in the Bering and Chukchi Seas and gray whales. 
Since June 1, 2018, elevated strandings for bearded, ringed and spotted 
seals have occurred in the Bering and Chukchi seas in Alaska, with 
causes undetermined. Through 2020, there were 315 recorded seal 
strandings. For more information, please visit: www.fisheries.noaa.gov/alaska/marine-life-distress/2018-2020-ice-seal-unusual-mortality-event-alaska.
    Since January 1, 2019, elevated gray whale strandings have occurred 
along the west coast of North America from Mexico through Alaska. As of 
April 5, 2021, there have been a total of 430 whales reported in the 
event, with approximately 205 dead whales in Mexico, 209 whales in the 
United States (including 93 in Alaska), and 16 whales in British 
Columbia, Canada. For the United States, the historical 18-year 5-month 
average (Jan-May) is 14.8 whales for this same time-period. Several 
dead whales have been emaciated with moderate to heavy whale lice 
(cyamid) loads. Necropsies have been conducted on a subset of whales 
with additional findings of vessel strike in three whales and 
entanglement in one whale. In Mexico, 50-55 percent of the free-ranging 
whales observed in the lagoons in winter have been reported as 
``skinny'' compared to the annual average of 10-12 percent ``skinny'' 
whales normally seen. The cause of the UME is as yet undetermined. For 
more information, please visit: www.fisheries.noaa.gov/national/marine-life-distress/2019-2020-gray-whale-unusual-mortality-event-along-west-coast-and.

Marine Mammal Hearing

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

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

    The pinniped functional hearing group was modified from Southall et 
al. (2007) on the basis of data indicating that phocid species have 
consistently demonstrated an extended frequency range of hearing 
compared to otariids, especially in the higher frequency range 
(Hemil[auml] et al., 2006; Kastelein et al., 2009; Reichmuth and Holt, 
2013).
    For more detail concerning these groups and associated frequency 
ranges,

[[Page 28794]]

please see NMFS (2018) for a review of available information. Thirteen 
marine mammal species (9 cetacean and 4 pinniped (all phocid) species) 
have the reasonable potential to co-occur with the proposed survey 
activities. Please refer to Table 1. Of the cetacean species that may 
be present, 5 are classified as low-frequency cetaceans (i.e., all 
mysticete species), 3 are classified as mid-frequency cetaceans (i.e., 
all delphinid species), and 1 is classified as high-frequency cetacean 
(i.e., harbor porpoise).

Potential Effects of Specified Activities on Marine Mammals and Their 
Habitat

    This section includes a summary of the ways that UAGI's specified 
activity may impact marine mammals and their habitat. Detailed 
descriptions of the potential effects of similar specified activities 
have been provided in other recent Federal Register notices, including 
for survey activities using the same methodology and over a similar 
amount of time, and affecting similar species (e.g., 83 FR 29212, June 
22, 2018; 84 FR 14200, April 9, 2019; 85 FR 19580, April 7, 2020). No 
significant new information is available, and we refer the reader to 
these documents for additional detail. The Estimated Take section 
includes a quantitative analysis of the number of individuals that are 
expected to be taken by UAGI's activity. The Negligible Impact Analysis 
and Determination section considers the potential effects of the 
specified activity, the Estimated Take section, and the Proposed 
Mitigation section, to draw conclusions regarding the likely impacts of 
these activities on the reproductive success or survivorship of 
individuals and how those impacts on individuals are likely to impact 
marine mammal species or stocks.

Background on Active Acoustic Sound Sources and Acoustic Terminology

    This section contains a brief technical background on sound, on the 
characteristics of certain sound types, and on metrics used in this 
proposal inasmuch as the information is relevant to the specified 
activity and to the discussion of the effects of the specified activity 
on marine mammals in this document. For general information on sound 
and its interaction with the marine environment, please see, e.g., Au 
and Hastings (2008); Richardson et al. (1995); Urick (1983).
    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 or cycles per second. Wavelength is the distance 
between two peaks or corresponding points of a sound wave (length of 
one cycle). Higher frequency sounds have shorter wavelengths than lower 
frequency sounds, and typically attenuate (decrease) more rapidly, 
except in certain cases in shallower water. Amplitude is the height of 
the sound pressure wave or the ``loudness'' of a sound and is typically 
described using the relative unit of the decibel. A sound pressure 
level (SPL) in dB is described as the ratio between a measured pressure 
and a reference pressure (for underwater sound, this is 1 microPascal 
([mu]Pa)), and is a logarithmic unit that accounts for large variations 
in amplitude. Therefore, a relatively small change in dB corresponds to 
large changes in sound pressure. The source level (SL) represents the 
SPL referenced at a distance of 1 m from the source (referenced to 1 
[mu]Pa), while the received level is the SPL at the listener's position 
(referenced to 1 [mu]Pa).
    Root mean square (rms) is the quadratic mean sound pressure over 
the duration of an impulse. Root mean square is calculated by squaring 
all of the sound amplitudes, averaging the squares, and then taking the 
square root of the average (Urick, 1983). Root mean square 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.
    Sound exposure level (SEL; represented as dB re 1 [mu]Pa\2\-s) 
represents the total energy in a stated frequency band over a stated 
time interval or event and considers both intensity and duration of 
exposure. The per-pulse SEL is calculated over the time window 
containing the entire pulse (i.e., 100 percent of the acoustic energy). 
SEL is a cumulative metric; it can be accumulated over a single pulse, 
or calculated over periods containing multiple pulses. Cumulative SEL 
represents the total energy accumulated by a receiver over a defined 
time window or during an event. Peak sound pressure (also referred to 
as zero-to-peak sound pressure or 0-pk) is the maximum instantaneous 
sound pressure measurable in the water at a specified distance from the 
source and is represented in the same units as the rms sound pressure.
    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 a 
manner similar to ripples on the surface of a pond and may be either 
directed in a beam or beams or may radiate in all directions 
(omnidirectional sources), as is the case for sound produced by the 
pile driving activity considered here. 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, which is 
defined as environmental background sound levels lacking a single 
source or point (Richardson et al., 1995). 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., wind and 
waves, earthquakes, ice, atmospheric sound), biological (e.g., sounds 
produced by marine mammals, fish, and invertebrates), and anthropogenic 
(e.g., vessels, dredging, construction) sound. A number of sources 
contribute to ambient sound, including wind and waves, which are a main 
source of naturally occurring ambient sound for frequencies between 200 
hertz (Hz) and 50 kilohertz (kHz) (Mitson, 1995). In general, ambient 
sound levels tend to increase with increasing wind speed and wave 
height. Precipitation can become an important component of total sound 
at frequencies above 500 Hz, and possibly down to 100 Hz during quiet 
times. Marine mammals can contribute significantly to ambient sound 
levels, as can some fish and snapping shrimp. The frequency band for 
biological contributions is from approximately 12 Hz to over 100 kHz. 
Sources of ambient sound related to human activity include 
transportation (surface vessels), dredging and construction, oil and 
gas drilling and production, geophysical surveys, sonar, and 
explosions. Vessel noise typically dominates the total ambient sound 
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.
    The sum of the various natural and anthropogenic sound sources that 
comprise ambient sound at any given location and time depends not only 
on the source levels (as determined by current weather conditions and 
levels of

[[Page 28795]]

biological and human activity) but also on the ability of sound to 
propagate through the environment. In turn, sound propagation is 
dependent on the spatially and temporally varying properties of the 
water column and sea floor, and is frequency-dependent. As a result of 
the dependence on a large number of varying factors, ambient sound 
levels can be expected to vary widely over both coarse and fine spatial 
and temporal scales. Sound levels at a given frequency and location can 
vary by 10-20 dB from day to day (Richardson et al., 1995). The result 
is that, depending on the source type and its intensity, sound from the 
specified activity may be a negligible addition to the local 
environment or could form a distinctive signal that may affect marine 
mammals. Details of source types are described in the following text.
    Sounds are often considered to fall into one of two general types: 
Pulsed and non-pulsed (defined in the following). 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. 
The distinction between these two sound types is not always obvious, as 
certain signals share properties of both pulsed and non-pulsed sounds. 
A signal near a source could be categorized as a pulse, but due to 
propagation effects as it moves farther from the source, the signal 
duration becomes longer (e.g., Greene and Richardson, 1988).
    Pulsed sound sources (e.g., airguns, 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, 2005; Harris, 1998; NIOSH, 1998; ISO, 2003) 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.
    Non-pulsed sounds can be tonal, narrowband, or broadband, brief or 
prolonged, and may be either continuous or intermittent (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. The 
duration of such sounds, as received at a distance, can be greatly 
extended in a highly reverberant environment.
    Airgun arrays produce pulsed signals with energy in a frequency 
range from about 10-2,000 Hz, with most energy radiated at frequencies 
below 200 Hz. The amplitude of the acoustic wave emitted from the 
source is equal in all directions (i.e., omnidirectional), but airgun 
arrays do possess some directionality due to different phase delays 
between guns in different directions. Airgun arrays are typically tuned 
to maximize functionality for data acquisition purposes, meaning that 
sound transmitted in horizontal directions and at higher frequencies is 
minimized to the extent possible.

Summary on Specific Potential Effects of Acoustic Sound Sources

    Underwater sound from active acoustic sources can include one or 
more of the following: Temporary or permanent hearing impairment, non-
auditory physical or physiological effects, behavioral disturbance, 
stress, and masking. The degree of effect is intrinsically related to 
the signal characteristics, received level, distance from the source, 
and duration of the sound exposure. Marine mammals exposed to high-
intensity sound, or to lower-intensity sound for prolonged periods, can 
experience hearing threshold shift (TS), which is the loss of hearing 
sensitivity at certain frequency ranges (Finneran, 2015). TS can be 
permanent (PTS), in which case the loss of hearing sensitivity is not 
fully recoverable, or temporary (TTS), in which case the animal's 
hearing threshold would recover over time (Southall et al., 2007).
    Animals in the vicinity of UAGI's proposed seismic survey activity 
are unlikely to incur PTS due to the small estimated auditory injury 
zones, in conjunction with the anticipated efficacy of the proposed 
mitigation requirements. Please see Estimated Take and Proposed 
Mitigation for further discussion.
    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. 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.
    In addition, 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). 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.
    Sound may affect marine mammals through impacts on the abundance, 
behavior, or distribution of prey species (e.g., crustaceans, 
cephalopods, fish, zooplankton) (i.e., effects to marine mammal 
habitat). Prey species exposed to sound might move away from the sound 
source, experience TTS, experience masking of biologically relevant 
sounds, or show no obvious direct effects. The most likely impacts (if 
any) for most prey species in a given area would be temporary avoidance 
of the area. Surveys using active acoustic sound sources move through 
an area relatively quickly, limiting exposure to multiple pulses. In 
all cases, sound levels would return to ambient once a survey ends and 
the noise source is shut down and, when exposure to sound ends, 
behavioral and/or physiological responses are expected to end 
relatively quickly. Finally, the survey equipment will not have 
significant impacts to the seafloor and does not represent a source of 
pollution.

Vessel Strike

    Vessel collisions with marine mammals, or ship strikes, can result 
in death or serious injury of the animal. These interactions are 
typically associated with large whales, which are less maneuverable 
than are smaller cetaceans or pinnipeds in relation to large vessels. 
The severity of injuries typically depends on the size and speed of the 
vessel, with the probability of

[[Page 28796]]

death or serious injury increasing as vessel speed increases (Knowlton 
and Kraus, 2001; Laist et al., 2001; Vanderlaan and Taggart, 2007; Conn 
and Silber, 2013). Impact forces increase with speed, as does the 
probability of a strike at a given distance (Silber et al., 2010; Gende 
et al., 2011). The chances of a lethal injury decline from 
approximately 80 percent at 15 kn to approximately 20 percent at 8.6 
kn. At speeds below 11.8 kn, the chances of lethal injury drop below 50 
percent (Vanderlaan and Taggart, 2007).
    Ship strikes generally involve commercial shipping, which is much 
more common in both space and time than is geophysical survey activity 
and which typically involves larger vessels moving at faster speeds. 
Jensen and Silber (2004) summarized ship strikes of large whales 
worldwide from 1975-2003 and found that most collisions occurred in the 
open ocean and involved large vessels (e.g., commercial shipping). 
Commercial fishing vessels were responsible for three percent of 
recorded collisions, while no such incidents were reported for 
geophysical survey vessels during that time period.
    For vessels used in geophysical survey activities, vessel speed 
while towing gear is typically only 4-5 knots. At these speeds, both 
the possibility of striking a marine mammal and the possibility of a 
strike resulting in serious injury or mortality are so low as to be 
discountable. At average transit speed for geophysical survey vessels 
(approximately 10 kn), the probability of serious injury or mortality 
resulting from a strike (if it occurred) is less than 50 percent 
(Vanderlaan and Taggart, 2007; Conn and Silber, 2013). However, the 
likelihood of a strike actually happening is again low given the 
smaller size of these vessels and generally slower speeds. We 
anticipate that vessel collisions involving seismic data acquisition 
vessels towing gear, while not impossible, represent unlikely, 
unpredictable events for which there are no preventive measures. Given 
the required mitigation measures, the relatively slow speeds of vessels 
towing gear, the presence of bridge crew watching for obstacles at all 
times (including marine mammals), the presence of marine mammal 
observers, and the small number of seismic survey cruises relative to 
commercial ship traffic, we believe that the possibility of ship strike 
is discountable and, further, that were a strike of a large whale to 
occur, it would be unlikely to result in serious injury or mortality. 
No incidental take resulting from ship strike is anticipated or 
proposed for authorization, and this potential effect of the specified 
activity will not be discussed further in the following analysis.
    The potential effects of UAGI's specified survey activity are 
expected to be limited to Level B behavioral harassment. No permanent 
auditory effects, or significant impacts to marine mammal habitat, 
including prey, are expected.

Estimated Take

    This section provides an estimate of the number of incidental takes 
proposed for authorization through this IHA, which will inform both 
NMFS' consideration of ``small numbers'' and the negligible impact 
determination.
    Harassment is the only type of take expected to result from these 
activities. Except with respect to certain activities not pertinent 
here, section 3(18) of 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, 
feeding, or sheltering (Level B harassment).
    Authorized takes would be by Level B harassment, as use of seismic 
airguns may result, either directly or as a result of TTS, in 
disruption of behavioral patterns of marine mammals. The proposed 
mitigation and monitoring measures are expected to minimize the 
severity of such taking to the extent practicable. Moreover, based on 
the nature of the activity and the anticipated effectiveness of the 
mitigation measures (i.e., implementation of extended shutdown 
distances for certain species)--discussed in detail below in the 
Proposed Mitigation section--Level A harassment is neither anticipated 
nor proposed to be authorized.
    As described previously, no mortality is anticipated or proposed to 
be authorized for this activity. Below we describe how the take is 
estimated.
    Generally speaking, we estimate take by considering: (1) Acoustic 
thresholds above which NMFS believes the best available science 
indicates marine mammals will be behaviorally 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. We note that while these basic 
factors can contribute to a basic calculation to provide an initial 
prediction of takes, additional information that can qualitatively 
inform take estimates is also sometimes available (e.g., previous 
monitoring results or average group size). Below, we describe the 
factors considered here in more detail and present the proposed take 
estimate.

Acoustic Thresholds

    NMFS recommends the use of acoustic thresholds that identify the 
received level of underwater sound above which exposed marine mammals 
would be reasonably expected to be behaviorally harassed (equated to 
Level B harassment) or to incur PTS of some degree (equated to Level A 
harassment).
    Level B Harassment for non-explosive sources--Though significantly 
driven by received level, the onset of behavioral disturbance from 
anthropogenic noise exposure is also informed to varying degrees by 
other factors related to the source (e.g., frequency, predictability, 
duty cycle), the environment (e.g., bathymetry), the receiving animals 
(hearing, motivation, experience, demography, behavioral context), and 
the distance between the sound source and the animal, and can be 
difficult to predict (Southall et al., 2007, Ellison et al., 2012). 
NMFS uses a generalized acoustic threshold based on received level to 
estimate the onset of behavioral harassment. NMFS predicts that marine 
mammals may be behaviorally harassed (i.e., Level B harassment) when 
exposed to underwater anthropogenic noise above received levels 160 dB 
re 1 [mu]Pa (rms) for the impulsive sources (i.e., seismic airguns) 
evaluated here.
    Level A harassment for non-explosive sources--NMFS' Technical 
Guidance for Assessing the Effects of Anthropogenic Sound on Marine 
Mammal Hearing (Version 2.0) (Technical Guidance, 2018) identifies dual 
criteria to assess auditory injury (Level A harassment) to five 
different marine mammal groups (based on hearing sensitivity) as a 
result of exposure to noise from two different types of sources 
(impulsive or non-impulsive). UAGI's proposed seismic survey includes 
the use of impulsive sources (seismic airgun).
    These thresholds are provided in Table 3 below. The references, 
analysis, and methodology used in the development of the thresholds are 
described in NMFS 2018 Technical Guidance, which may be accessed at 
https://www.fisheries.noaa.gov/national/marine-mammal-protection/
marine-mammal-acoustic-technical-guidance.

[[Page 28797]]



                     Table 3--Thresholds Identifying the Onset of Permanent Threshold Shift
----------------------------------------------------------------------------------------------------------------
                                                    PTS onset acoustic thresholds * (received level)
             Hearing group             -------------------------------------------------------------------------
                                                Impulsive                          Non-impulsive
----------------------------------------------------------------------------------------------------------------
Low-Frequency (LF) Cetaceans..........  Cell 1: Lpk,flat: 219 dB;  Cell 2: LE,LF,24h: 199 dB.
                                         LE,LF,24h: 183 dB.
Mid-Frequency (MF) Cetaceans..........  Cell 3: Lpk,flat: 230 dB;  Cell 4: LE,MF,24h: 198 dB.
                                         LE,MF,24h: 185 dB.
High-Frequency (HF) Cetaceans.........  Cell 5: Lpk,flat: 202 dB;  Cell 6: LE,HF,24h: 173 dB.
                                         LE,HF,24h: 155 dB.
Phocid Pinnipeds (PW) (Underwater)....  Cell 7: Lpk,flat: 218 dB;  Cell 8: LE,PW,24h: 201 dB.
                                         LE,PW,24h: 185 dB.
Otariid Pinnipeds (OW) (Underwater)...  Cell 9:Lpk,flat: 232 dB;   Cell 10:LE,OW,24h: 219 dB.
                                         LE,OW,24h: 203 dB.
----------------------------------------------------------------------------------------------------------------
* Dual metric acoustic thresholds for impulsive sounds: Use whichever results in the largest isopleth for
  calculating PTS onset. If a non-impulsive sound has the potential of exceeding the peak sound pressure level
  thresholds associated with impulsive sounds, these thresholds should also be considered.
Note: Peak sound pressure (Lpk) has a reference value of 1 [micro]Pa, and cumulative sound exposure level (LE)
  has a reference value of 1[micro]Pa\2\s. In this Table, thresholds are abbreviated to reflect American
  National Standards Institute standards (ANSI 2013). However, peak sound pressure is defined by ANSI as
  incorporating frequency weighting, which is not the intent for this Technical Guidance. Hence, the subscript
  ``flat'' is being included to indicate peak sound pressure should be flat weighted or unweighted within the
  generalized hearing range. The subscript associated with cumulative sound exposure level thresholds indicates
  the designated marine mammal auditory weighting function (LF, MF, and HF cetaceans, and PW and OW pinnipeds)
  and that the recommended accumulation period is 24 hours. The cumulative sound exposure level thresholds could
  be exceeded in a multitude of ways (i.e., varying exposure levels and durations, duty cycle). When possible,
  it is valuable for action proponents to indicate the conditions under which these acoustic thresholds will be
  exceeded.

Ensonified Area

    Here, we describe operational and environmental parameters of the 
activity that will feed into identifying the area ensonified above the 
acoustic thresholds, which include source levels and acoustic 
propagation modeling.
    The acoustic propagation modeling methodologies are described in 
greater detail in Appendix A of UAGI's IHA application. The proposed 
survey would primarily acquire data using the 2-airgun array with a 
total discharge volume of 1,040 in\3\ and an approximately 15-second 
shot interval. During approximately 12 percent of the planned survey 
tracklines, the 6-airgun, 3,120 in\3\ array would be used with a 60-
second shot interval. All tracklines would be surveyed with a maximum 
tow depth of 9 m. The modeling assumed an airgun firing pressure of 
2,540 psi. Propagation modeling for UAGI's application follows the 
approach used by the Lamont-Doherty Earth Observatory (L-DEO) for 
other, similar IHA applications. L-DEO uses ray tracing for the direct 
wave traveling from the array to the receiver and its associated source 
ghost (reflection at the air-water interface in the vicinity of the 
array), in a constant-velocity half-space (infinite homogeneous ocean 
layer, unbounded by a seafloor). To validate the model results, L-DEO 
measured propagation of pulses from a 36-airgun array at a tow depth of 
6 m in the Gulf of Mexico, for deep water (~1,600 m), intermediate 
water depth on the slope (~600-1,100 m), and shallow water (~50 m) 
(Tolstoy et al., 2009; Diebold et al., 2010).
    L-DEO collected a MCS data set from R/V Marcus G. Langseth (with 
the same 36-airgun array referenced above) on an 8 km streamer in 2012 
on the shelf of the Cascadia Margin off of Washington in water up to 
200 m deep that allowed Crone et al. (2014) to analyze the hydrophone 
streamer (>1,100 individual shots). These empirical data were then 
analyzed to determine in situ sound levels for shallow and upper 
intermediate water depths. These data suggest that modeled radii were 
2-3 times larger than the measured radii in shallow water. Similarly, 
data collected by Crone et al. (2017) during a survey off New Jersey in 
2014 and 2015 confirmed that in situ measurements collected by R/V 
Langseth hydrophone streamer were 2-3 times smaller than the predicted 
radii.
    L-DEO model results are used to determine the assumed radial 
distance to the 160-dB rms threshold for these arrays in deep water 
(>1,000 m) (down to a maximum water depth of 2,000 m) (see Table 4). 
Water depths in the project area may be up to 4,000 m, but marine 
mammals in the region are generally not anticipated to dive below 2,000 
m (Costa and Williams, 1999). The radii for intermediate water depths 
(100-1000 m) are derived from the deep-water ones by applying a 
correction factor (multiplication) of 1.5. No survey effort would occur 
in water depths <100 m.
    The area expected to be ensonified was determined by entering the 
planned survey lines into a GIS and then ``buffering'' the lines by the 
applicable 160-dB distance (see Appendix B in IHA application). The 
resulting ensonified areas were then increased by 25% to allow for any 
necessary additional operations, such as re-surveying segments where 
data quality was insufficient. This approach assumes that no marine 
mammals would move away or toward the trackline in response to 
increasing sound levels before the levels reach the threshold as R/V 
Sikuliaq approaches.

         Table 4--Predicted Radial Distances to Isopleths Corresponding to Level B Harassment Threshold
----------------------------------------------------------------------------------------------------------------
                                                                                                      Level B
               Source and volume                 Tow depth (m)           Water depth (m)            harassment
                                                                                                     zone (m)
----------------------------------------------------------------------------------------------------------------
6 airgun array; 3,120 in\3\...................               9  >1,000..........................       \1\ 4,640
                                                                100-1,000.......................       \3\ 6,960
2 airgun array; 1,040 in\3\...................               9  >1,000..........................       \1\ 1,604
                                                                100-1,000.......................       \2\ 2,406
----------------------------------------------------------------------------------------------------------------
\1\ Distance based on L-DEO model results.
\2\ Based on L-DEO model results with 1.5x correction factor applied.


[[Page 28798]]

    Predicted distances to Level A harassment isopleths, which vary 
based on marine mammal hearing groups, were calculated based on L-DEO 
modeling performed using the NUCLEUS source modeling software program 
and the NMFS User Spreadsheet, described below. The acoustic thresholds 
for impulsive sounds (e.g., airguns) contained in the Technical 
Guidance were presented as dual metric acoustic thresholds using both 
SELcum and peak sound pressure metrics (NMFS 2018). As dual 
metrics, NMFS considers onset of PTS (Level A harassment) to have 
occurred when either one of the two metrics is exceeded (i.e., metric 
resulting in the largest isopleth). The SELcum metric 
considers both level and duration of exposure, as well as auditory 
weighting functions by marine mammal hearing group. In recognition of 
the fact that the requirement to calculate Level A harassment 
ensonified areas could be more technically challenging to predict due 
to the duration component and the use of weighting functions in the new 
SELcum thresholds, NMFS developed an optional User 
Spreadsheet that includes tools to help predict a simple isopleth that 
can be used in conjunction with marine mammal density or occurrence to 
facilitate the estimation of take numbers.
    The values for SELcum and peak SPL were derived from 
calculating the modified far-field signature. The farfield signature is 
often used as a theoretical representation of the source level. To 
compute the farfield signature, the source level is estimated at a 
large distance below the array (e.g., 9 km), and this level is back 
projected mathematically to a notional distance of 1 m from the array's 
geometrical center. However, when the source is an array of multiple 
airguns separated in space, the source level from the theoretical 
farfield signature is not necessarily the best measurement of the 
source level that is physically achieved at the source (Tolstoy et al., 
2009). Near the source (at short ranges, distances <1 km), the pulses 
of sound pressure from each individual airgun in the source array do 
not stack constructively, as they do for the theoretical farfield 
signature. The pulses from the different airguns spread out in time 
such that the source levels observed or modeled are the result of the 
summation of pulses from a few airguns, not the full array (Tolstoy et 
al., 2009). At larger distances, away from the source array center, 
sound pressure of all the airguns in the array stack coherently, but 
not within one time sample, resulting in smaller source levels (a few 
dB) than the source level derived from the farfield signature. Because 
the farfield signature does not take into account the large array 
effect near the source and is calculated as a point source, the 
modified farfield signature is a more appropriate measure of the sound 
source level for distributed sound sources, such as airgun arrays. The 
acoustic modeling methodology as used for estimating Level B harassment 
distances with a small grid step of 1 m in both the inline and depth 
directions. The propagation modeling takes into account all airgun 
interactions at short distances from the source, including interactions 
between subarrays, which are modeled using the NUCLEUS software to 
estimate the notional signature and MATLAB software to calculate the 
pressure signal at each mesh point of a grid.
    In order to more realistically incorporate the Technical Guidance's 
weighting functions over the seismic array's full acoustic band, 
unweighted spectrum data (modeled in 1 Hz bands) were used to make 
adjustments (dB) to the unweighted spectrum levels, by frequency, 
according to the weighting functions for each relevant marine mammal 
hearing group. These adjusted/weighted spectrum levels were then 
converted to pressures ([mu]Pa) in order to integrate them over the 
entire broadband spectrum, resulting in broadband weighted source 
levels by hearing group that could be directly incorporated within the 
User Spreadsheet (i.e., to override the Spreadsheet's more simple 
weighting factor adjustment). Using the User Spreadsheet's ``safe 
distance'' methodology for mobile sources (described by Sivle et al., 
2014) with the hearing group-specific weighted source levels, and 
inputs assuming spherical spreading propagation and source velocities 
and shot intervals specific to the planned survey, potential radial 
distances to auditory injury zones were then calculated for 
SELcum thresholds. For full detail of the modeling 
methodology used for estimating distance to Level A harassment peak 
pressure and cumulative SEL criteria, please see Appendix A of UAGI's 
application.
    Inputs to the User Spreadsheets in the form of estimated source 
levels are shown in Appendix A of UAGI's application. User Spreadsheets 
used by UAGI to estimate distances to Level A harassment isopleths for 
the airgun arrays are also provided in Appendix A of the application. 
Outputs from the User Spreadsheets in the form of estimated distances 
to Level A harassment isopleths for the survey are shown in Table 5. As 
described above, NMFS considers onset of PTS (Level A harassment) to 
have occurred when either one of the dual metrics (SELcum 
and Peak SPLflat) is exceeded (i.e., metric resulting in the 
largest isopleth).

        Table 5--Modeled Radial Distances (m) to Isopleths Corresponding to Level A Harassment Thresholds
----------------------------------------------------------------------------------------------------------------
                                                                    Level A harassment zone (m)
        Source (volume)             Threshold    ---------------------------------------------------------------
                                                   LF cetaceans    MF cetaceans    HF cetaceans       Phocids
----------------------------------------------------------------------------------------------------------------
6-airgun array (3,120 in\3\)..  SELcum..........              51               0               0               0
                                Peak............              30               7             212              34
2-airgun array (1,040 in\3\)..  SELcum..........              17               0               0               0
                                Peak............              10               3              73               2
----------------------------------------------------------------------------------------------------------------

    Note that because of some of the assumptions included in the 
methods used (e.g., stationary receiver with no vertical or horizontal 
movement in response to the acoustic source), isopleths produced may be 
overestimates to some degree, which will ultimately result in some 
degree of overestimation of Level A harassment. However, these tools 
offer the best way to predict appropriate isopleths when more 
sophisticated modeling methods are not available. NMFS continues to 
develop ways to quantitatively refine these tools and will 
qualitatively address the output where appropriate. For mobile sources, 
such as the proposed seismic survey, the User

[[Page 28799]]

Spreadsheet predicts the closest distance at which a stationary animal 
would not incur PTS if the sound source traveled by the animal in a 
straight line at a constant speed.
    Auditory injury is unlikely to occur for mid-frequency and low-
frequency cetaceans given very small modeled zones of injury for those 
species (all estimated zones less than 10 m for mid-frequency 
cetaceans, up to a maximum of 51 m for low-frequency cetaceans and 34 m 
for phocid pinnipeds), in context of distributed source dynamics. 
Similarly, for high-frequency cetaceans, the maximum modeled injury 
zone for the low-energy array (88 percent of survey effort) is 73 m and 
auditory injury would be unlikely to occur during use of that array. 
The source level of the array is a theoretical definition assuming a 
point source and measurement in the far-field of the source 
(MacGillivray, 2006). As described by Caldwell and Dragoset (2000), an 
array is not a point source, but one that spans a small area. In the 
far-field, individual elements in arrays will effectively work as one 
source because individual pressure peaks will have coalesced into one 
relatively broad pulse. The array can then be considered a ``point 
source.'' For distances within the near-field, i.e., approximately 2-3 
times the array dimensions, pressure peaks from individual elements do 
not arrive simultaneously because the observation point is not 
equidistant from each element. The effect is destructive interference 
of the outputs of each element, so that peak pressures in the near-
field will be significantly lower than the output of the largest 
individual element. Here, the estimated Level A harassment isopleth 
distances would in all cases (other than for high-frequency cetaceans) 
be expected to be within the near-field of the array where the 
definition of source level breaks down. Therefore, actual locations 
within this distance of the array center where the sound level exceeds 
relevant harassment criteria would not necessarily exist.
    In consideration of the received sound levels in the near-field as 
described above, we expect the potential for Level A harassment of low- 
and mid-frequency cetaceans and phocid pinnipeds to be de minimis, even 
before the likely moderating effects of aversion and/or other 
compensatory behaviors (e.g., Nachtigall et al., 2018) are considered. 
A similar conclusion may be drawn for high-frequency cetaceans relative 
to use of the low-energy airgun array. We do not believe that Level A 
harassment is a likely outcome for any low- or mid-frequency cetacean 
or phocid pinniped and do not propose to authorize any Level A 
harassment for these species. For high-frequency cetaceans, the larger 
estimated Level A harassment zone associated with the high-energy array 
would be present for only 12 percent of total survey effort, and given 
the expected rarity of occurrence for harbor porpoise, no incidents of 
Level A harassment are expected.

Marine Mammal Occurrence

    In this section we provide the information about the presence, 
density, or group dynamics of marine mammals that will inform the take 
calculations. Density values are shown in Table 6.
    Cetacean densities in the U.S. Arctic were published by Schick et 
al. (2017). This study used line-transect aerial survey data from ASAMM 
collected in the U.S. Chukchi and Beaufort seas from 2000-2016 and 
associated habitat covariates to estimate abundance monthly within 10 
km x 10 km grid cells (equivalent to a density in units of individuals/
100km\2\). Estimates were produced for bowhead, gray, and beluga 
whales, as well as other baleen whales such as fin, humpback, and minke 
whales. The spatial extent of the model predictions differed by 
species, but for all species other than bowhead whale and beluga whale 
was further south than the planned location of the UAGI survey. In 
general, marine mammals are expected to be encountered more frequently 
to the south of the proposed survey location. Therefore, estimated take 
numbers produced through use of the density model products are expected 
to be a very conservative estimate. Previous monitoring reports from 
recent Arctic surveys using the same research vessel saw a total of 
three humpback whales, 1 spotted seal, 4 unknown seals (Please see the 
following link for more detailed information on this monitoring report: 
https://media.fisheries.noaa.gov/dam-migration/onr_arcticresearch_2018iha_monrep_opr1.pdf). Furthermore, based on 
tagged surveys from the summer and fall, bowhead whales migrate across 
the continental shelf of Alaska in the Beaufort Sea to the central 
Chukchi Sea in September and remain in this area for the fall 
(Quakenbush, Small & Citta, 2013). Only one whale was reported to 
travel north towards the proposed survey area. With this information in 
mind, NMFS believes that the proposed take numbers conservatively 
estimate the number of bowhead whales that will be encountered during 
the proposed activity.
    For all species, except for beluga whales, UAGI extended the Schick 
et al. (2017) density values to calculate predictions for areas farther 
north. The spatial coverage of density estimates for bowhead whales 
extends northward to ~74 [deg]N, which overlaps with the southern-most 
survey lines by ~25 km. However, the majority of the survey lines do 
not overlap with spatial coverage of the Schick et al. (2017) density 
estimates, so the following method was used to produce a conservative 
estimate of average bowhead density farther north. The two northern-
most rows of 10km x 10km grid cells (ie., northern 20 km of estimates) 
and the two additional cells overlapped by the southern-most survey 
lines were selected from the bowhead whale GIS raster files for August 
and September between 140[deg]W and 165[deg]W, the approximate east-
west extent of the survey lines. Density estimates within those cells 
were then evaluated and cells east of ~157[deg]W were excluded as they 
contained densities that were effectively zero which would reduce the 
calculated average. The mean of the remaining cells (west of 157[deg]W) 
was then calculated.
    The same process was used to calculate densities for gray whales, 
fin whales, humpback whales, and minke whales. However the northern 
survey coverage from Schick et al. (2017) for these species extends 
only to ~73[deg]N. This meant that there was no overlap with any of the 
survey lines and no additional cells beyond the two northernmost rows 
(20km) were used in the calculations. The resulting density estimates 
were extremely small.
    For beluga whales, the spatial coverage of the Schick et al. (2017) 
density estimates overlapped the full extent of the survey lines and 
associated ensonified areas. To calculate an average beluga whale 
density in areas that may be exposed above threshold levels, UAGI 
selected all grid cells from the August and September estimates that 
overlapped (wholly or partially) with estimated the 160 dB ensonified 
area around the planned tracklines and calculated the mean.
    During ASAMM, sightings of pinnipeds were recorded when possible 
and the resulting data were used by Schick et al. (2017) to produce 
habitat-based estimates in the same manner as cetaceans. However, given 
ASAMM was designed for large whales, including typically being flown at 
altitudes above 304.8 feet (ft) ASL, and small pinniped sightings may 
not have been recorded as consistently, the Schick et al (2017) 
pinniped densities were not used in this analysis. Instead, bearded and 
ringed seal densities from NMFS's Biological Opinion for the Navy's 
Arctic Research

[[Page 28800]]

Activities 2018-2021 were used (NMFS 2019b), which were based on 
habitat-based modeling by Kaschner et al. (2006) and Kaschner (2004).
    Spotted and ribbon seals were not included in NMFS (2019b). Thus, 
spotted seal densities were estimated by multiplying the ringed seal 
density by the ratio of the estimated Chukchi Sea populations of the 
two species. The best estimate of the Alaskan population of spotted 
seals is 461,625 (Muto et al., 2020), and ~8% of the population 
(~37,000) is estimated to be present in the Chukchi Sea during the 
summer and fall (Rugh et al., 1997). As the best estimate of the 
population of ringed seals in the Alaskan Chukchi Sea is ~208,000 
animals (Bengtson et al., 2005), this resulted in a ratio of 0.18. 
Based on Hartin et al., (2013), four ribbon seal sightings were 
reported during vessel operations in the Chukchi Sea from 2006 through 
2010, resulting in a density estimate of 0.0007/km\2\.
    Highly variable oceanographic and atmospheric conditions determine 
the distribution of sea ice in the Arctic, which heavily influences the 
species and number of marine mammals potentially present at these high 
latitudes. Thus, there is considerable year-to-year variation in the 
distribution and abundance of the marine mammal species in the survey 
area. For some species, the densities derived from past surveys may not 
be representative of the densities that would be encountered during the 
proposed seismic surveys. However, the approach used here is based on 
the best available data.

   Table 6--Density Values Used for Take Analysis, Calculated by UAGI
------------------------------------------------------------------------
               Species                    Density  (individuals/km\2\)
------------------------------------------------------------------------
Bowhead whale........................  0.0124.
Gray whale...........................  0.
Fin whale............................  0.
Humpback whale.......................  0.
Minke whale..........................  0.
Beluga whale.........................  0.0255.
Killer whale.........................  Unknown.
Narwhal..............................  Unknown.
Harbor porpoise......................  Unknown.
Bearded seal.........................  0.0332.
Ribbon seal..........................  0.0677.
Ringed seal..........................  0.376.
Spotted seal.........................  0.0007.
------------------------------------------------------------------------

Take Calculation and Estimation

    Here we describe how the information provided above is brought 
together to produce a quantitative take estimate. In order to estimate 
the number of marine mammals predicted to be exposed to sound levels 
that would result in Level A or Level B harassment, radial distances 
from the airgun array to predicted isopleths corresponding to the Level 
A harassment and Level B harassment thresholds are calculated, as 
described above. Those radial distances are then used to calculate the 
area(s) around the airgun array predicted to be ensonified to sound 
levels that exceed the Level A and Level B harassment thresholds. The 
distance for the 160-dB threshold (based on L-DEO model results) was 
used to draw a buffer around every transect line in GIS to determine 
the total ensonified area in each depth category. Estimated incidents 
of exposure above Level A and Level B harassment criteria are presented 
in Table 7. As noted previously, UAGI has added 25 percent in the form 
of operational days, which is equivalent to adding 25 percent to the 
proposed line-kilometers to be surveyed. This accounts for the 
possibility that additional operational days are required, and is 
included in the estimates of actual exposures.
    The number of individual marine mammals potentially exposed to 
airgun sounds with received levels >= 160 dB re 1 
[micro]Parms (Level B) was estimated following NSF's take 
calculation method by multiplying the estimated densities by the total 
area expected to be ensonified above the Level threshold. The total 
ensonified area was multiplied by 25 percent to account for any 
necessary additional operations, such as re-surveying segments where 
data quality was insufficient. This approach assumes that no marine 
mammals would move away or toward the trackline in response to 
increasing sound levels before the levels reach the threshold as R/V 
Sikuliaq approaches. This value was then multiplied by the estimated 
densities for each species to produce estimated Level B takes. Given 
the location of the survey being far north in the Arctic, we expect 
that the density values, and thus estimated take numbers, are 
conservative estimates of what is likely to be encountered during the 
survey.

                                Table 7--Estimated Taking by Level A and Level B Harassment, and Percentage of Population
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                             Estimated       Estimated
              Species                     Stock \1\           Level B         Level A     Proposed Level  Proposed Level    Total take      Percent of
                                                            harassment      harassment     B harassment    A harassment                      stock \1\
--------------------------------------------------------------------------------------------------------------------------------------------------------
Bowhead whale.....................  Western Arctic......             339               3             342               0             342            2.03
Humpback whale \2\................  WN Pacific..........               0               0               2               0               2            0.00
Fin whale \2\ \4\.................  NE Pacific..........               0               0               2               0               2            0.00
Gray whale \2\....................  EN Pacific..........               0               0               2               0               2            0.00
Minke whale \2\ \4\...............  Alaska..............               0               0               2               0               2            0.00
Beluga whale......................  Beaufort Sea........             696               7             703               0             703            1.34
                                    Eastern Chukchi.....
Killer whale \2\..................  Alaska Resident.....               0               0               6               0               6            0.00
Narwhal \3\ \4\...................  Unidentified........               0               0               2               0               2             n/a
Harbor porpoise \2\ \4\...........  Bering Sea..........               0               0               2               0               2            0.00
Bearded seal......................  Beringia............             907               9             916               0             916            0.73
Ringed seal.......................  Arctic..............          10,268             105          10,373               0          10,373            6.05
Spotted seal......................  Bering..............              19               0              19               0              19            0.00
Ribbon seal.......................  Unidentified........            1849              19            1868               0            1868            1.01
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ In most cases, where multiple stocks are being affected, for the purposes of calculating the percentage of the stock impacted, the take is being
  analyzed as if all proposed takes occurred within each stock. Where necessary, additional discussion is provided in the ``Small Numbers Analysis''
  section.
\2\ UAGI requests authorization of gray whale, humpback whale, fin whale, minke whale, killer whale, and harbor porpoise take equivalent to exposure of
  one group (Clarke et al., 2016; Clarke et al., 2017; Clarke et al., 2018; Clarke et al., 2019).
\3\ UAGI requests authorization of two takes of narwhals.
\4\ As noted in Table 1, there is no estimate of abundance available for these species. See ``Small Numbers Analysis'' section for further discussion.


[[Page 28801]]

    Although, gray whales, fin whales, humpback whales, minke whales, 
narwhals and harbor porpoises are not expected to occur this far north 
in the Arctic, we agree with NSF that there is possibility that the 
proposed activity might encounter these species and thus a conservative 
number of takes based on average group size from yearly Aerial Surveys 
of Arctic Marine Mammals (ASAMM) (Clark et al., 2016, 2017, 2018, 2019) 
has been proposed.

Proposed Mitigation

    In order to issue an IHA under section 101(a)(5)(D) of the MMPA, 
NMFS must set forth the permissible methods of taking pursuant to the 
activity, and other means of effecting the least practicable impact on 
the species or stock and its habitat, paying particular attention to 
rookeries, mating grounds, and areas of similar significance, and on 
the availability of the species or stock for taking for certain 
subsistence uses. NMFS regulations require applicants for incidental 
take authorizations to include information about the availability and 
feasibility (economic and technological) of equipment, methods, and 
manner of conducting the activity or other means of effecting the least 
practicable adverse impact upon the affected species or stocks and 
their habitat (50 CFR 216.104(a)(11)).
    In evaluating how mitigation may or may not be appropriate to 
ensure the least practicable adverse impact on species or stocks and 
their habitat, as well as subsistence uses where applicable, we 
carefully consider two primary factors:
    (1) The manner in which, and the degree to which, the successful 
implementation of the measure(s) is expected to reduce impacts to 
marine mammals, marine mammal species or stocks, and their habitat, as 
well as subsistence uses. This considers the nature of the potential 
adverse impact being mitigated (likelihood, scope, range). It further 
considers the likelihood that the measure will be effective if 
implemented (probability of accomplishing the mitigating result if 
implemented as planned), the likelihood of effective implementation 
(probability implemented as planned), and;
    (2) The practicability of the measures for applicant 
implementation, which may consider such things as cost and impact on 
operations.
    In order to satisfy the MMPA's least practicable adverse impact 
standard, NMFS has evaluated a suite of basic mitigation protocols for 
seismic surveys that are required regardless of the status of a stock. 
Additional or enhanced protections may be required for species whose 
stocks are in particularly poor health and/or are subject to some 
significant additional stressor that lessens that stock's ability to 
weather the effects of the specified activities without worsening its 
status. We reviewed seismic mitigation protocols required or 
recommended elsewhere (e.g., HESS, 1999; DOC, 2013; IBAMA, 2018; Kyhn 
et al., 2011; JNCC, 2017; DEWHA, 2008; BOEM, 2016; DFO, 2008; GHFS, 
2015; MMOA, 2016; Nowacek et al., 2013; Nowacek and Southall, 2016), 
recommendations received during public comment periods for previous 
actions, and the available scientific literature. We also considered 
recommendations given in a number of review articles (e.g., Weir and 
Dolman, 2007; Compton et al., 2008; Parsons et al., 2009; Wright and 
Cosentino, 2015; Stone, 2015b). This exhaustive review and 
consideration of public comments regarding previous, similar activities 
has led to development of the protocols included here.
    Due to the use of high- and low-energy airgun arrays used within 
this survey, two separate mitigation protocols are proposed for use 
throughout the activity depending on which array is in use (Table 8).

Vessel-Based Visual Mitigation Monitoring

    Visual monitoring requires the use of trained observers (herein 
referred to as visual Protected Species Observers (PSOs)) to scan the 
ocean surface for the presence of marine mammals. The area to be 
scanned visually includes primarily the EZ, within which observation of 
certain marine mammals requires shutdown of the acoustic source, but 
also a buffer zone. The buffer zone means an area beyond the EZ to be 
monitored for the presence of marine mammals that may enter the EZ. 
During pre-clearance monitoring (i.e., before ramp-up begins), the 
buffer zone also acts as an extension of the EZ in that observations of 
marine mammals within the buffer zone would also prevent airgun 
operations from beginning (i.e., ramp-up). The standard EZ is 500 m 
from the edges of the airgun array for high energy surveys and 100 m 
for low energy surveys. For high energy surveys, the buffer zone 
encompasses the area at and below the sea surface from the edge of the 
0-500 m EZ, out to a radius of 1,000 m from the edges of the airgun 
array (500-1,000 m). For low energy surveys, the buffer zone 
encompasses the area at and below the sea surface from the edge of the 
0-100 m EZ, out to a radius of 200 m from the edges of the airgun array 
(100-200 m).
    Visual monitoring of the EZ and buffer zones is intended to 
establish and, when visual conditions allow, maintain zones around the 
sound source that are clear of marine mammals, thereby reducing or 
eliminating the potential for injury and minimizing the potential for 
more severe behavioral reactions for animals occurring closer to the 
vessel. Visual monitoring of the buffer zone is intended to (1) provide 
additional protection to na[iuml]ve marine mammals that may be in the 
area during pre-clearance, and (2) during airgun use, aid in 
establishing and maintaining the EZ by alerting the visual observer and 
crew of marine mammals that are outside of, but may approach and enter, 
the EZ.
    UAGI must use dedicated, trained, NMFS-approved PSOs. The PSOs must 
have no tasks other than to conduct observational effort, record 
observational data, and communicate with and instruct relevant vessel 
crew with regard to the presence of marine mammals and mitigation 
requirements. PSO resumes shall be provided to NMFS for approval.
    At least one of the visual PSOs aboard the vessel must have a 
minimum of 90 days at-sea experience working in the roles, with no more 
than 18 months elapsed since the conclusion of the at-sea experience. 
One visual PSO with such experience shall be designated as the lead for 
the entire protected species observation team. The lead PSO shall serve 
as primary point of contact for the vessel operator and ensure all PSO 
requirements per the IHA are met. To the maximum extent practicable, 
the experienced PSOs should be scheduled to be on duty with those PSOs 
with appropriate training but who have not yet gained relevant 
experience.
    During survey operations (e.g., any day on which use of the 
acoustic source is planned to occur, and whenever the acoustic source 
is in the water, whether activated or not), a minimum of two visual 
PSOs must be on duty and conducting visual observations at all times 
during daylight hours (i.e., from 30 minutes prior to sunrise through 
30 minutes following sunset). Visual monitoring of the EZ and buffer 
zone must begin no less than 30 minutes prior to ramp-up and must 
continue until one hour after use of the acoustic source ceases or 
until 30 minutes past sunset. Visual PSOs shall coordinate to ensure 
360[deg] visual coverage around the vessel from the most appropriate 
observation posts, and shall conduct visual observations using 
binoculars and the naked eye while free from distractions and in a 
consistent, systematic, and diligent manner.

[[Page 28802]]

    PSOs shall establish and monitor the EZ and buffer zone. These 
zones shall be based upon the radial distance from the edges of the 
acoustic source (rather than being based on the center of the array or 
around the vessel itself). During use of the acoustic source (i.e., 
anytime airguns are active, including ramp-up), detections of marine 
mammals within the buffer zone (but outside the EZ) shall be 
communicated to the operator to prepare for the potential shutdown of 
the acoustic source.
    During use of the airgun (i.e., anytime the acoustic source is 
active, including ramp-up), detections of marine mammals within the 
buffer zone (but outside the EZ) should be communicated to the operator 
to prepare for the potential shutdown of the acoustic source. Visual 
PSOs will immediately communicate all observations to the on duty 
acoustic PSO(s), including any determination by the PSO regarding 
species identification, distance, and bearing and the degree of 
confidence in the determination. Any observations of marine mammals by 
crew members shall be relayed to the PSO team. During good conditions 
(e.g., daylight hours; Beaufort sea state (BSS) 3 or less), visual PSOs 
shall conduct observations when the acoustic source is not operating 
for comparison of sighting rates and behavior with and without use of 
the acoustic source and between acquisition periods, to the maximum 
extent practicable.
    Visual PSOs may be on watch for a maximum of four consecutive hours 
followed by a break of at least one hour between watches and may 
conduct a maximum of 12 hours of observation per 24-hour period. 
Combined observational duties (visual and acoustic but not at same 
time) may not exceed 12 hours per 24-hour period for any individual 
PSO.

Establishment of Exclusion and Buffer Zones

    An EZ is a defined area within which occurrence of a marine mammal 
triggers mitigation action intended to reduce the potential for certain 
outcomes, e.g., auditory injury, disruption of behavioral patterns. The 
PSOs would establish a minimum EZ with a 500- or 100-m radius, during 
use of the high energy and low energy arrays, respectively, for all 
species except bowhead whales. The EZ would be based on radial distance 
from the edge of the airgun array (rather than being based on the 
center of the array or around the vessel itself).
    The EZs are intended to be precautionary in the sense that they 
would be expected to contain sound exceeding the injury criteria for 
all cetacean hearing groups, (based on the dual criteria of 
SELcum and peak SPL), while also providing a consistent, 
reasonably observable zone within which PSOs would typically be able to 
conduct effective observational effort. Additionally, the EZs are 
expected to minimize the likelihood that marine mammals will be exposed 
to levels likely to result in more severe behavioral responses. 
Although significantly greater distances may be observed from an 
elevated platform under good conditions, we believe that these 
distances are likely regularly attainable for PSOs using the naked eye 
during typical conditions.
    An extended EZ of 1,500/500 m must be implemented for all bowhead 
whales during high energy and low energy survey effort, respectively, 
because of their importance to subsistence hunters and protected 
status. No buffer of this extended EZ is required.

Pre-Clearance and Ramp-Up

    Ramp-up (sometimes referred to as ``soft start'') means the gradual 
and systematic increase of emitted sound levels from an airgun array. 
Ramp-up begins by first activating a single airgun of the smallest 
volume, followed by doubling the number of active elements in stages 
until the full complement of an array's airguns are active. Each stage 
should be approximately the same duration, and the total duration 
should not be less than approximately 20 minutes for high energy airgun 
arrays. Ramp-up for the low energy array, which includes only two 
elements, may be shorter. The intent of pre-clearance observation (30 
minutes) is to ensure no protected species are observed within the 
buffer zone prior to the beginning of ramp-up. During pre-clearance is 
the only time observations of protected species in the buffer zone 
would prevent operations (i.e., the beginning of ramp-up). The intent 
of ramp-up is to warn protected species of pending seismic operations 
and to allow sufficient time for those animals to leave the immediate 
vicinity. A ramp-up procedure, involving a step-wise increase in the 
number of airguns firing and total array volume until all operational 
airguns are activated and the full volume is achieved, is required at 
all times as part of the activation of the acoustic source. All 
operators must adhere to the following pre-clearance and ramp-up 
requirements:
     The operator must notify a designated PSO of the planned 
start of ramp-up as agreed upon with the lead PSO; the notification 
time should not be less than 60 minutes prior to the planned ramp-up in 
order to allow the PSOs time to monitor the EZ and buffer zone for 30 
minutes prior to the initiation of ramp-up (pre-clearance);
     Ramp-ups shall be scheduled so as to minimize the time 
spent with the source activated prior to reaching the designated run-
in;
     One of the PSOs conducting pre-clearance observations must 
be notified again immediately prior to initiating ramp-up procedures 
and the operator must receive confirmation from the PSO to proceed;
     Ramp-up may not be initiated if any marine mammal is 
within the applicable EZ or buffer zone. If a marine mammal is observed 
within the applicable EZ or the buffer zone during the 30 minute pre-
clearance period, ramp-up may not begin until the animal(s) has been 
observed exiting the zones or until an additional time period has 
elapsed with no further sightings (15 minutes for small odontocetes and 
pinnipeds, and 30 minutes for all mysticetes and all other odontocetes, 
including large delphinids, such as beluga whales and killer whales);
     Ramp-up shall begin by activating a single airgun of the 
smallest volume in the array and shall continue in stages by doubling 
the number of active elements at the commencement of each stage, with 
each stage of approximately the same duration. Duration shall not be 
less than 20 minutes for high energy arrays. The operator must provide 
information to the PSO documenting that appropriate procedures were 
followed;
     PSOs must monitor the relevant EZ and buffer zone during 
ramp-up, and ramp-up must cease and the source must be shut down upon 
detection of a marine mammal within the applicable EZ. Once ramp-up has 
begun, detections of marine mammals within the buffer zone do not 
require shutdown, but such observation shall be communicated to the 
operator to prepare for the potential shutdown;
     Ramp-up may occur at times of poor visibility, including 
nighttime, if appropriate acoustic monitoring has occurred with no 
detections in the 30 minutes prior to beginning ramp-up. Acoustic 
source activation may only occur at times of poor visibility where 
operational planning cannot reasonably avoid such circumstances;
     If the acoustic source is shut down for brief periods 
(i.e., less than 30 minutes) for reasons other than that described for 
shutdown (e.g., mechanical difficulty), it may be activated again 
without ramp-up if PSOs have maintained constant visual and/or acoustic 
observation and no visual or acoustic detections of marine mammals

[[Page 28803]]

have occurred within the applicable EZ. For any longer shutdown, pre-
clearance observation and ramp-up are required. For any shutdown at 
night or in periods of poor visibility (e.g., BSS 4 or greater), ramp-
up is required, but if the shutdown period was brief and constant 
observation was maintained, pre-clearance watch of 30 minutes is not 
required; and
     Testing of the acoustic source involving all elements 
requires ramp-up. Testing limited to individual source elements or 
strings does not require ramp-up but does require pre-clearance of 30 
min.

Shutdown

    The shutdown of an airgun array requires the immediate de-
activation of all individual airgun elements of the array. Any PSO on 
duty will have the authority to delay the start of survey operations or 
to call for shutdown of the acoustic source if a marine mammal is 
detected within the applicable EZ. The operator must also establish and 
maintain clear lines of communication directly between PSOs on duty and 
crew controlling the acoustic source to ensure that shutdown commands 
are conveyed swiftly while allowing PSOs to maintain watch. When the 
airgun array is active (i.e., anytime one or more airguns is active, 
including during ramp-up) and a marine mammal appears within or enters 
the applicable EZ, the acoustic source will be shut down. When shutdown 
is called for by a PSO, the acoustic source will be immediately 
deactivated and any dispute resolved only following deactivation.
    Following a shutdown, airgun activity would not resume until the 
marine mammal has cleared the EZ. The animal would be considered to 
have cleared the EZ if it is visually observed to have departed the EZ, 
or it has not been seen within the EZ for 15 min in the case of small 
odontocetes and pinnipeds, or 30 min in the case of mysticetes and 
large odontocetes, including beluga whales and killer whales.
    Upon implementation of shutdown, the source may be reactivated 
after the marine mammal(s) has been observed exiting the applicable EZ 
(i.e., animal is not required to fully exit the buffer zone where 
applicable) or following 15 minutes for small odontocetes and 
pinnipeds, and 30 minutes for mysticetes and all other odontocetes, 
including beluga whales and killer whales, with no further observation 
of the marine mammal(s).
    UAGI must implement shutdown if a marine mammal species for which 
take was not authorized, or a species for which authorization was 
granted but the takes have been met, approaches the Level A or Level B 
harassment zones. L-DEO must also implement shutdown if any of the 
following are observed at any distance:
     Any large whale (defined as any mysticete species) with a 
calf (defined as an animal less than two-thirds the body size of an 
adult observed to be in close association with an adult); and/or
     An aggregation of six or more large whales.

Passive Acoustic Monitoring (PAM)

    NMFS does not propose to require use of PAM for this activity. NMFS 
typically recommends use of PAM as part of prescribed mitigation 
requirements for high energy surveys, but not for low energy surveys, 
which here comprise approximately 88 percent of the planned survey. 
Therefore, PAM would only be applicable to the small portion of the 
proposed survey (12 percent) using the high-energy array. In addition, 
use of towed PAM is not generally expected to be effective in detecting 
mysticetes, due to overlap in the frequencies of mysticete 
vocalizations with the noise from the airgun array as well as from the 
vessel itself and flow noise around the towed PAM receiver. Species of 
greatest interest in prescribing use of towed PAM (e.g., sperm whales, 
beaked whales) are not present in the planned survey area. Further, 
UAGI has indicated that it would not be practicable to carry the 
additional monitoring personnel required for implementation of towed 
PAM. The R/V Sikuliaq is a smaller research vessel with limited space.

 Table 8--Proposed Mitigation Protocols for High- and Low-Energy Arrays
------------------------------------------------------------------------
 
------------------------------------------------------------------------
                          Mitigation Protocols
------------------------------------------------------------------------
Sources.....................  High Energy (6-       Low Energy (2-airgun
                               airgun array with     array with 1040
                               3120 in\3\ total      in\3\ total
                               discharge volume).    discharge volume).
Visual PSOs.................  Minimum of 2 NMFS-    Minimum of 2 NMFS-
                               approved PSOs on      approved PSOs on
                               duty during           duty during
                               daylight hours (30    daylight hours (30
                               minutes before        minutes before
                               sunrise through 30    sunrise through 30
                               minutes after         minutes after
                               sunset); Limit of 2   sunset); Limit of 2
                               consecutive hours     consecutive hours
                               on watch followed     on watch followed
                               by a break of at      by a break of at
                               least 1 hour;         least 1 hour;
                               Maximum of 12 hours   Maximum of 12 hours
                               on watch per 24-      on watch per 24-
                               hour period.          hour period.
Passive acoustic monitoring.  Not Required........  Not required.
Exclusion zones.............   500 m (all    100 m (all
                               marine mammals).      marine mammals).
                               1,500 m       500 m
                               (Bowhead whales).     (Bowhead whales).
Pre-start clearance.........  Required; 30-minute   Required; 30-minute
                               clearance period of   clearance period of
                               the following         the following
                               zones:                zones:
                               1,000 m       200 m (all
                               (all marine           marine mammals).
                               mammals).
                               1,500 m       500 m
                               (Bowhead whales).     (Bowhead whales).
                              Following detection   Following detection
                               within zone, animal   within zone, animal
                               must be observed      must be observed
                               exiting or            exiting or
                               additional period     additional period
                               of 15 or 30 minutes.  of 15 or 30
                                                     minutes.
Ramp-up.....................  Required; duration    Required; duration
                               >=20 minutes.         not more than 20
                                                     minutes.
Shutdown....................  Shutdown required     Shutdown required
                               for marine mammal     for marine mammal
                               detected within       detected within
                               defined EZs; Re-      defined EZs; Re-
                               start allowed         start allowed
                               following clearance   following clearance
                               period of 15 or 30    period of 15 or 30
                               minutes.              minutes
------------------------------------------------------------------------

Vessel Strike Avoidance

    1. Vessel operators and crews must maintain a vigilant watch for 
all protected species and slow down, stop their vessel, or alter 
course, as appropriate and regardless of vessel size, to avoid striking 
any protected species. A visual observer aboard the vessel must monitor 
a vessel strike avoidance zone around the vessel (distances stated 
below). Visual observers monitoring the vessel strike avoidance zone 
may be third-party observers (i.e., PSOs) or crew members, but crew 
members responsible for these

[[Page 28804]]

duties must be provided sufficient training to 1) distinguish marine 
mammals from other phenomena, and 2) broadly identify a marine mammal 
as a bowhead whale, other whale (defined in this context as baleen 
whales other than bowhead whales), or other marine mammal.
    2. Vessel speeds must also be reduced to 10 knots or less when 
mother/calf pairs, pods, or large assemblages of cetaceans are observed 
near a vessel.
    3. All vessels must maintain a minimum separation distance of 500 m 
from bowhead whales. If a whale is observed but cannot be confirmed as 
a species other than a bowhead whale, the vessel operator must assume 
that it is a bowhead whale and take appropriate action.
    4. All vessels must maintain a minimum separation distance of 100 m 
from all other baleen whales.
    5. All vessels must, to the maximum extent practicable, attempt to 
maintain a minimum separation distance of 50 m from all other marine 
mammals, with an understanding that at times this may not be possible 
(e.g., for animals that approach the vessel).
    6. When marine mammals are sighted while a vessel is underway, the 
vessel shall take action as necessary to avoid violating the relevant 
separation distance (e.g., attempt to remain parallel to the animal's 
course, avoid excessive speed or abrupt changes in direction until the 
animal has left the area). If protected species are sighted within the 
relevant separation distance, the vessel must reduce speed and shift 
the engine to neutral, not engaging the engines until animals are clear 
of the area. This does not apply to any vessel towing gear or any 
vessel that is navigationally constrained.
    7. These requirements do not apply in any case where compliance 
would create an imminent and serious threat to a person or vessel or to 
the extent that a vessel is restricted in its ability to maneuver and, 
because of the restriction, cannot comply.
    We did not identify any mitigation specifically appropriate for 
habitat. Marine mammal habitat may be impacted by elevated sound 
levels, but these impacts would be temporary. Prey species are mobile 
and are broadly distributed throughout the project area; therefore, 
marine mammals that may be temporarily displaced during survey 
activities are expected to be able to resume foraging once they have 
moved away from areas with disturbing levels of underwater noise. The 
specified activity is if relatively short duration (30 days) and the 
disturbance will be temporary in nature, similar habitat and resources 
are available in the surrounding area, the impacts to marine mammals 
and the food sources that they utilize are not expected to cause 
significant or long-term consequences for individual marine mammals or 
their populations. No BIAs, designated critical habitat, or other 
habitat of known significance would be impacted by the planned 
activities.
    We have carefully evaluated the suite of mitigation measures 
described here and considered a range of other measures in the context 
of ensuring that we prescribe the means of effecting the least 
practicable adverse impact on the affected marine mammal species and 
stocks and their habitat. Based on our evaluation of the proposed 
measures, as well as other measures considered by NMFS described above, 
NMFS has preliminarily determined that the mitigation measures provide 
the means of effecting the least practicable impact on the affected 
species or stocks and their habitat, paying particular attention to 
rookeries, mating grounds, and areas of similar significance, and on 
the availability of such species or stock for subsistence uses (see 
Unmitigable Adverse Impact Analysis and Determination).

Proposed Monitoring and Reporting

    In order to issue an IHA for an activity, section 101(a)(5)(D) of 
the MMPA states that NMFS must set forth requirements pertaining to the 
monitoring and reporting of such taking. The MMPA implementing 
regulations at 50 CFR 216.104 (a)(13) indicate that requests for 
authorizations must include the suggested means of accomplishing the 
necessary monitoring and reporting that will result in increased 
knowledge of the species and of the level of taking or impacts on 
populations of marine mammals that are expected to be present in the 
proposed action area. Effective reporting is critical both to 
compliance as well as ensuring that the most value is obtained from the 
required monitoring.
    Monitoring and reporting requirements prescribed by NMFS should 
contribute to improved understanding of one or more of the following:
     Occurrence of marine mammal species or stocks in the area 
in which take is anticipated (e.g., presence, abundance, distribution, 
density).
     Nature, scope, or context of likely marine mammal exposure 
to potential stressors/impacts (individual or cumulative, acute or 
chronic), through better understanding of: (1) Action or environment 
(e.g., source characterization, propagation, ambient noise); (2) 
affected species (e.g., life history, dive patterns); (3) co-occurrence 
of marine mammal species with the action; or (4) biological or 
behavioral context of exposure (e.g., age, calving or feeding areas).
     Individual marine mammal responses (behavioral or 
physiological) to acoustic stressors (acute, chronic, or cumulative), 
other stressors, or cumulative impacts from multiple stressors.
     How anticipated responses to stressors impact either: (1) 
Long-term fitness and survival of individual marine mammals; or (2) 
populations, species, or stocks.
     Effects on marine mammal habitat (e.g., marine mammal prey 
species, acoustic habitat, or other important physical components of 
marine mammal habitat).
     Mitigation and monitoring effectiveness.

Vessel-Based Visual Monitoring

    As described above, PSO observations would take place during 
daytime airgun operations. During seismic operations, at least five 
visual PSOs would be based aboard the R/V Sikuliaq. Two visual PSOs 
would be on duty at all time during daytime hours. Monitoring shall be 
conducted in accordance with the following requirements:
     The operator shall provide PSOs with bigeye binoculars 
(e.g., 25 x 150; 2.7 view angle; individual ocular focus; height 
control) of appropriate quality (i.e., Fujinon or equivalent) solely 
for PSO use. These shall be pedestal-mounted on the deck at the most 
appropriate vantage point that provides for optimal sea surface 
observation, PSO safety, and safe operation of the vessel; and
     The operator will work with the selected third-party 
observer provider to ensure PSOs have all equipment (including backup 
equipment) needed to adequately perform necessary tasks, including 
accurate determination of distance and bearing to observed marine 
mammals.
    PSOs must have the following requirements and qualifications:
     PSOs shall be independent, dedicated, trained visual and 
acoustic PSOs and must be employed by a third-party observer provider;
     PSOs shall have no tasks other than to conduct 
observational effort, collect data, and communicate with and instruct 
relevant vessel crew with regard to the presence of protected species 
and mitigation requirements (including brief alerts regarding maritime 
hazards);

[[Page 28805]]

     PSOs shall have successfully completed an approved PSO 
training course;
     NMFS must review and approve PSO resumes accompanied by a 
relevant training course information packet that includes the name and 
qualifications (i.e., experience, training completed, or educational 
background) of the instructor(s), the course outline or syllabus, and 
course reference material as well as a document stating successful 
completion of the course;
     NMFS shall have one week to approve PSOs from the time 
that the necessary information is submitted, after which PSOs meeting 
the minimum requirements shall automatically be considered approved;
     PSOs must successfully complete relevant training, 
including completion of all required coursework and passing (80 percent 
or greater) a written and/or oral examination developed for the 
training program;
     PSOs must have successfully attained a bachelor's degree 
from an accredited college or university with a major in one of the 
natural sciences, a minimum of 30 semester hours or equivalent in the 
biological sciences, and at least one undergraduate course in math or 
statistics; and
     The educational requirements may be waived if the PSO has 
acquired the relevant skills through alternate experience. Requests for 
such a waiver shall be submitted to NMFS and must include written 
justification. Requests shall be granted or denied (with justification) 
by NMFS within one week of receipt of submitted information. Alternate 
experience that may be considered includes, but is not limited to (1) 
secondary education and/or experience comparable to PSO duties; (2) 
previous work experience conducting academic, commercial, or 
government-sponsored protected species surveys; or (3) previous work 
experience as a PSO; the PSO should demonstrate good standing and 
consistently good performance of PSO duties. Traditional ecological 
knowledge is also a relevant consideration.
    For data collection purposes, PSOs shall use standardized data 
collection forms, whether hard copy or electronic. PSOs shall record 
detailed information about any implementation of mitigation 
requirements, including the distance of animals to the acoustic source 
and description of specific actions that ensued, the behavior of the 
animal(s), any observed changes in behavior before and after 
implementation of mitigation, and if shutdown was implemented, the 
length of time before any subsequent ramp-up of the acoustic source. If 
required mitigation was not implemented, PSOs should record a 
description of the circumstances. At a minimum, the following 
information must be recorded:
     Vessel names (source vessel and other vessels associated 
with survey) and call signs;
     PSO names and affiliations;
     Dates of departures and returns to port with port name;
     Date and participants of PSO briefings;
     Dates and times (Greenwich Mean Time) of survey effort and 
times corresponding with PSO effort;
     Vessel location (latitude/longitude) when survey effort 
began and ended and vessel location at beginning and end of visual PSO 
duty shifts;
     Vessel heading and speed at beginning and end of visual 
PSO duty shifts and upon any line change;
     Environmental conditions while on visual survey (at 
beginning and end of PSO shift and whenever conditions changed 
significantly), including BSS and any other relevant weather conditions 
including cloud cover, fog, sun glare, and overall visibility to the 
horizon;
     Factors that may have contributed to impaired observations 
during each PSO shift change or as needed as environmental conditions 
changed (e.g., vessel traffic, equipment malfunctions); and
     Survey activity information, such as acoustic source power 
output while in operation, number and volume of airguns operating in 
the array, tow depth of the array, and any other notes of significance 
(i.e., pre-clearance, ramp-up, shutdown, testing, shooting, ramp-up 
completion, end of operations, streamers, etc.).
    The following information should be recorded upon visual 
observation of any protected species:
     Watch status (sighting made by PSO on/off effort, 
opportunistic, crew, alternate vessel/platform);
     PSO who sighted the animal;
     Time of sighting;
     Vessel location at time of sighting;
     Water depth;
     Direction of vessel's travel (compass direction);
     Direction of animal's travel relative to the vessel;
     Pace of the animal;
     Estimated distance to the animal and its heading relative 
to vessel at initial sighting;
     Identification of the animal (e.g., genus/species, lowest 
possible taxonomic level, or unidentified) and the composition of the 
group if there is a mix of species;
     Estimated number of animals (high/low/best);
     Estimated number of animals by cohort (adults, yearlings, 
juveniles, calves, group composition, etc.);
     Description (as many distinguishing features as possible 
of each individual seen, including length, shape, color, pattern, scars 
or markings, shape and size of dorsal fin, shape of head, and blow 
characteristics);
     Detailed behavior observations (e.g., number of blows/
breaths, number of surfaces, breaching, spyhopping, diving, feeding, 
traveling; as explicit and detailed as possible; note any observed 
changes in behavior);
     Animal's closest point of approach (CPA) and/or closest 
distance from any element of the acoustic source;
     Platform activity at time of sighting (e.g., deploying, 
recovering, testing, shooting, data acquisition, other); and
     Description of any actions implemented in response to the 
sighting (e.g., delays, shutdown, ramp-up) and time and location of the 
action.

Reporting

    A report would be submitted to NMFS within 90 days after the end of 
the cruise. The report would describe the operations that were 
conducted and sightings of marine mammals near the operations. The 
report would provide full documentation of methods, results, and 
interpretation pertaining to all monitoring. The 90-day report would 
summarize the dates and locations of seismic operations, and all marine 
mammal sightings (dates, times, locations, activities, associated 
seismic survey activities).
    The draft report shall also include geo-referenced time-stamped 
vessel tracklines for all time periods during which airguns were 
operating. Tracklines should include points recording any change in 
airgun status (e.g., when the airguns began operating, when they were 
turned off, or when they changed from full array to single gun or vice 
versa). GIS files shall be provided in ESRI shapefile format and 
include the UTC date and time, latitude in decimal degrees, and 
longitude in decimal degrees. All coordinates shall be referenced to 
the WGS84 geographic coordinate system. In addition to the report, all 
raw observational data shall be made available to NMFS. The report must 
summarize the data collected as described above and in the IHA. A final 
report must be submitted within 30 days following resolution of any 
comments on the draft report.

[[Page 28806]]

Reporting Injured or Dead Marine Mammals

    Discovery of injured or dead marine mammals--In the event that 
personnel involved in survey activities covered by the authorization 
discover an injured or dead marine mammal, the UAGI shall report the 
incident to the Office of Protected Resources (OPR), NMFS and to the 
NMFS Alaska Regional Stranding Coordinator as soon as feasible. The 
report must include the following information:
     Time, date, and location (latitude/longitude) of the first 
discovery (and updated location information if known and applicable);
     Species identification (if known) or description of the 
animal(s) involved;
     Condition of the animal(s) (including carcass condition if 
the animal is dead);
     Observed behaviors of the animal(s), if alive;
     If available, photographs or video footage of the 
animal(s); and
     General circumstances under which the animal was 
discovered.
    Vessel strike--In the event of a ship strike of a marine mammal by 
any vessel involved in the activities covered by the authorization, 
UAGI shall report the incident to OPR, NMFS and to the NMFS Alaska 
Regional Stranding Coordinator as soon as feasible. The report must 
include the following information:
     Time, date, and location (latitude/longitude) of the 
incident;
     Vessel's speed during and leading up to the incident;
     Vessel's course/heading and what operations were being 
conducted (if applicable);
     Status of all sound sources in use;
     Description of avoidance measures/requirements that were 
in place at the time of the strike and what additional measure were 
taken, if any, to avoid strike;
     Environmental conditions (e.g., wind speed and direction, 
Beaufort sea state, cloud cover, visibility) immediately preceding the 
strike;
     Species identification (if known) or description of the 
animal(s) involved;
     Estimated size and length of the animal that was struck;
     Description of the behavior of the animal immediately 
preceding and following the strike;
     If available, description of the presence and behavior of 
any other marine mammals present immediately preceding the strike;
     Estimated fate of the animal (e.g., dead, injured but 
alive, injured and moving, blood or tissue observed in the water, 
status unknown, disappeared); and
     To the extent practicable, photographs or video footage of 
the animal(s).

Negligible Impact Analysis and Determination

    NMFS has defined negligible impact as an impact resulting from the 
specified activity that cannot be reasonably expected to, and is not 
reasonably likely to, adversely affect the species or stock through 
effects on annual rates of recruitment or survival (50 CFR 216.103). A 
negligible impact finding is based on the lack of likely adverse 
effects on annual rates of recruitment or survival (i.e., population-
level effects). An estimate of the number of takes alone is not enough 
information on which to base an impact determination. In addition to 
considering estimates of the number of marine mammals that might be 
``taken'' through harassment, NMFS considers other factors, such as the 
likely nature of any responses (e.g., intensity, duration), the context 
of any responses (e.g., critical reproductive time or location, 
migration), as well as effects on habitat, and the likely effectiveness 
of the mitigation. We also assess the number, intensity, and context of 
estimated takes by evaluating this information relative to population 
status. Consistent with the 1989 preamble for NMFS's implementing 
regulations (54 FR 40338; September 29, 1989), the impacts from other 
past and ongoing anthropogenic activities are incorporated into this 
analysis via their impacts on the environmental baseline (e.g., as 
reflected in the regulatory status of the species, population size and 
growth rate where known, ongoing sources of human-caused mortality, or 
ambient noise levels).
    To avoid repetition, our analysis applies to all species listed in 
Table 1, given that NMFS expects the anticipated effects of the planned 
geophysical survey to be similar in nature. Where there are meaningful 
differences between species or stocks, or groups of species, in 
anticipated individual responses to activities, impact of expected take 
on the population due to differences in population status, or impacts 
on habitat, NMFS has identified species-specific factors to inform the 
analysis.
    NMFS does not anticipate that injury, serious injury or mortality 
would occur as a result of UAGI's planned survey, even in the absence 
of mitigation, and none would be authorized. Similarly, non-auditory 
physical effects, stranding, and vessel strike are not expected to 
occur. Although a few incidents of Level A harassment were predicted 
through the quantitative exposure estimation process (see Estimated 
Take), NMFS has determined that this is not a realistic result due to 
the small estimated Level A harassment zones for the species (no 
greater than approximately 50 m) and the proposed mitigation 
requirements, and no Level A harassment is proposed for authorization. 
These estimated zones are larger than what would realistically occur, 
as discussed in the Estimated Take section. Although no Level A 
harassment would be expected to occur even absent mitigation, the 
extended distance exclusion zones proposed for bowhead whales further 
strengthen this conclusion.
    We expect that takes would be in the form of short-term Level B 
behavioral harassment in the form of temporary avoidance of the area or 
decreased foraging (if such activity were occurring), reactions that 
are considered to be of low severity and with no lasting biological 
consequences (e.g., Southall et al., 2007, Ellison et al., 2012). The 
proposed number of takes for bowhead whales is 2 percent of the 
population. We expect this number to be even smaller as the likelihood 
of encountering these animals in deep waters in the Northern Arctic 
Ocean are slim based on recent telemetry data (Quakenbush, Small & 
Citta, 2013).
    Marine mammal habitat may be impacted by elevated sound levels, but 
these impacts would be temporary. Prey species are mobile and are 
broadly distributed throughout the project area; therefore, marine 
mammals that may be temporarily displaced during survey activities are 
expected to be able to resume foraging once they have moved away from 
areas with disturbing levels of underwater noise. Because of the 
relatively short duration (30 days) and temporary nature of the 
disturbance, the availability of similar habitat and resources in the 
surrounding area, the impacts to marine mammals and the food sources 
that they utilize are not expected to cause significant or long-term 
consequences for individual marine mammals or their populations. No 
BIAs, designated critical habitat, or other habitat of known 
significance would be impacted by the planned activities.

Negligible Impact Conclusions

    The proposed survey would be of short duration (30 days of seismic 
operations), and the acoustic ``footprint'' of the proposed survey 
would be small relative to the ranges of the marine mammals that would 
potentially be affected. Sound levels would increase in

[[Page 28807]]

the marine environment in a relatively small area surrounding the 
vessel compared to the range of the marine mammals within the proposed 
survey area. Short term exposures to survey operations are expected to 
only temporarily affect marine mammal behavior in the form of 
avoidance, and the potential for longer-term avoidance of important 
areas is limited. Short term exposures to survey operations are not 
likely to impact marine mammal behavior, and the potential for longer-
term avoidance of important areas is limited.
    The proposed mitigation measures are expected to reduce the number 
and/or severity of takes by allowing for detection of marine mammals in 
the vicinity of the vessel by visual observers, and by minimizing the 
severity of any potential exposures via shutdowns of the airgun array.
    NMFS concludes that exposures to marine mammal species and stocks 
due to UAGI's proposed survey would result in only short-term 
(temporary and short in duration) effects to individuals exposed, over 
relatively small areas of the affected animals' ranges. Animals may 
temporarily avoid the immediate area, but are not expected to 
permanently abandon the area. Major shifts in habitat use, 
distribution, or foraging success are not expected. NMFS does not 
anticipate the proposed take estimates to impact annual rates of 
recruitment or survival.
    In summary and as described above, the following factors primarily 
support our preliminary determination that the impacts resulting from 
this activity are not expected to adversely affect the species or stock 
through effects on annual rates of recruitment or survival:
     No Level A harassment, serious injury or mortality is 
anticipated or proposed to be authorized;
     The proposed activity is temporary and of relatively short 
duration (30 days);
     The anticipated impacts of the proposed activity on marine 
mammals would primarily be temporary behavioral changes in the form of 
avoidance of the area around the survey vessel;
     Location of the survey is further north in the Arctic 
Ocean and away from areas where most of the species listed in Table 1 
have been observed and is north of summer feeding areas and migratory 
routes.
     The availability of alternate areas of similar habitat 
value for marine mammals to temporarily vacate the survey area during 
the proposed survey to avoid exposure to sounds from the activity;
     The potential adverse effects on fish or invertebrate 
species that serve as prey species for marine mammals from the proposed 
survey would be temporary and spatially limited, and impacts to marine 
mammal foraging would be minimal; and
     The proposed mitigation measures, including visual 
monitoring, shutdowns, ramp-up, and prescribed measures based on energy 
size are expected to minimize potential impacts to marine mammals (both 
amount and severity).
    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.

Small Numbers

    As noted above, only small numbers of incidental take may be 
authorized under sections 101(a)(5)(A) and (D) of the MMPA for 
specified activities other than military readiness activities. The MMPA 
does not define small numbers and so, in practice, where estimated 
numbers are available, NMFS compares the number of individuals taken to 
the most appropriate estimation of abundance of the relevant species or 
stock in our determination of whether the take is limited to small 
numbers of marine mammals. When the predicted number of individuals to 
be taken is fewer than one third of the species or stock abundance, the 
take is considered to be of small numbers (see 86 Federal Register 
5322, 5439 (January 19, 2021). Additionally, other qualitative factors 
may be considered in the analysis, such as the temporal or spatial 
scale of the activities.
    There are several stocks for which there is no currently accepted 
stock abundance estimate. These include the fin whale, minke whale, 
narwhal, bearded seal, and ringed seal. In those cases, qualitative 
factors are used to inform an assessment of whether the likely number 
of individual marine mammals taken is appropriately considered small. 
We discuss these in further detail below.
    For all other stocks (aside from those without accepted abundance 
estimates), the proposed take is less than 7% of the best available 
stock abundance, well less than the one-third threshold for exceeding 
small numbers (and some of those takes may be repeats of the same 
individual, thus rendering the actual percentage even lower). We also 
acknowledge that, given the location of the planned survey activity 
high in the Arctic Ocean, the stock ranges referenced in the SARs do 
not always fully overlap the area of the planned survey activity. 
However, given the very small percentage of the best available stock 
abundance estimates for these species and the likelihood that the 
numbers of take proposed for authorization would be very small relative 
to any reasonable population abundance estimate, we conclude these 
numbers are small.
    The stock abundance estimates for fin whale, minke whale, narwhal, 
bearded seal and ringed seal stocks that occur in the surveys area are 
unknown, according to the latest SARs. Therefore, we reviewed other 
scientific information in making our small numbers determinations for 
these animals. The abundance estimate of 20,000 minke whales was taken 
from the Northwest Pacific and Okhotsk Sea (IWC 2021). In addition, as 
noted previously, partial abundance estimates of 1,233 and 2,020 minke 
whales are available for shelf and nearshore waters between the Kenai 
Peninsula and Amchitka Pass and for the eastern Bering Sea shelf, 
respectively. For the minke whale, these partial abundance estimates 
alone are sufficient to demonstrate that the proposed take number of 2 
is of small numbers. The same surveys produced partial abundance 
estimates of 1,652 and 1,061 fin whales, for the same areas, 
respectively, which are similarly sufficient to demonstrate that the 
proposed take number of 2 is small numbers. The bearded seal estimate 
of 125,000 was estimated for the U.S. portion of the Bering Sea (Boveng 
et al., 2017) and 155,000 bearded seals for the entire Alaska stock 
(Cameron et al., 2010). These partial abundance estimates near the 
proposed survey are sufficient to demonstrate that the proposed take 
number of 916 seals is small numbers. Similarly, the ringed seal 
abundance estimate of 171,418 ringed seals was based on a limited sub-
sample from the Bering Sea (Conn et al., 2014 in Muto et al., 2020). 
This minimal abundance estimate for the Alaska region is enough to 
demonstrate that a take of 10,373 will be small numbers at 6.05% of the 
Bering Sea population. There is no abundance information available for 
narwhals. However, the take number is sufficiently small (2) that we 
assume that it is small relative to any reasonable assumption of likely 
population abundance for the narwhal. Additionally, the proposed survey 
area

[[Page 28808]]

encompasses a very small portion of the hypothesized range of the 
species.
    Based on the analysis contained herein of the proposed activity 
(including the proposed mitigation and monitoring measures) and the 
anticipated take of marine mammals, NMFS preliminarily finds that small 
numbers of marine mammals will be taken relative to the population size 
of the affected species or stocks.

Unmitigable Adverse Impact Analysis and Determination

    In order to issue an IHA, NMFS must find that the specified 
activity will not have an ``unmitigable adverse impact'' on the 
subsistence uses of the affected marine mammal species or stocks by 
Alaskan Natives. NMFS has defined ``unmitigable adverse impact'' in 50 
CFR 216.103 as an impact resulting from the specified activity: (1) 
That is likely to reduce the availability of the species to a level 
insufficient for a harvest to meet subsistence needs by: (i) Causing 
the marine mammals to abandon or avoid hunting areas; (ii) Directly 
displacing subsistence users; or (iii) Placing physical barriers 
between the marine mammals and the subsistence hunters; and (2) That 
cannot be sufficiently mitigated by other measures to increase the 
availability of marine mammals to allow subsistence needs to be met.
    The coast and nearshore waters of Alaska are of cultural importance 
to indigenous peoples for fishing, hunting, gathering, and ceremonial 
purposes. Marine mammals are legally hunted in Alaskan waters by 
coastal Alaska Natives. There are seven communities in the North Slope 
Borough region of Alaska (northwestern and northern Alaska) that 
harvest seals, including from west to east Point Hope, Point Lay, 
Wainwright, Utqia[gdot]vik, Atqusak, Nuiqsut, and Kaktovik (Ice Seal 
Committee 2019). Bearded seals are the preferred species to harvest as 
food and for skin boat coverings, but ringed seals are also commonly 
taken for food and their blubber (Ice Seal Committee 2019). Ringed 
seals are typically harvested during the summer and can extend up to 64 
km from shore (Stephen R. Braund & Associates 2010). No ribbon seals 
have been harvested in any of the North Slope Borough communities since 
the 1960s (Ice Seal Committee 2019). However, the number of seals 
harvested each year varies considerably.
    A subsistence harvest of bowheads and belugas is also practiced by 
Alaskan Natives, providing nutritional and cultural needs. In 2019, 36 
bowhead whales were taken during the Alaskan subsistence hunt (Suydam 
et al., 2020). Whaling near Utqia[gdot]vik occurs during spring (April 
and May) and autumn, and can continue into November, depending on the 
quota and conditions. Communities that harvested bowheads during 2019 
include Utqia[gdot]vik, Gamgell, Kaktovik, Nuiqsut, Point Hope, Point 
Lay, and Wainwright. Bowhead whales and gray whales are also taken in 
the aboriginal subsistence hunt in the Russian Federation (Zharikov et 
al., 2020). During 2019, 135 gray whales and one bowhead whale were 
harvested at Chukotka.
    Beluga whales from the eastern Chukchi Sea stock are an important 
subsistence resource for residents of the village of Point Lay, 
adjacent to Kasegaluk Lagoon, and other villages in northwest Alaska. 
Each year, hunters from Point Lay drive belugas into the lagoon to a 
traditional hunting location. The belugas have been predictably sighted 
near the lagoon from late June through mid to late July (Suydam et al., 
2001). The mean annual number of Beaufort Sea belugas landed by Alaska 
Native subsistence hunters in 2011-2015 was 47, and an average of 92 
were taken in Canadian waters; the mean annual number of Eastern 
Chukchi Sea belugas landed by Alaska Native subsistence hunters in 
2011-2015 was 67 (Muto et al., 2020).
    The proposed survey by UAGI will occur within ~73.5-81.0 [deg]N, 
~139.5-168 [deg]W and over 300 km from the Alaska coastline. Due to the 
location of the survey being far north in the Arctic and over 200 
kilometers from any hunting area or buffer (http://www.north-slope.org/assets/images/uploads/bowhead%20migration%20map%2021mar03%20distribution.pdf), no impacts on 
the availability of marine mammals for subsistence uses are expected to 
occur. Specifically, based on the survey methods and location proposed, 
there is no reason to believe that there will be any behavioral 
disturbance of bowhead whales that would also impact their behavior in 
a manner that would interfere with subsistence use later. Although 
fishing/hunting would not be precluded in the survey area, a safe 
distance would need to be kept from R/V Sikuliaq and the towed seismic 
equipment. The principal investigator for the survey has presented the 
proposed action to the Alaska Eskimo Whaling Commission (AEWC) at the 
July 2020, October 2020, and February 2021 Triannual Meetings. As 
specifically noted, during the meetings, daily email communications 
with interested community members would be made from the vessel. 
Communication may include notice of any unusual marine mammal 
observations during the survey. Any potential space use conflicts would 
be further avoided through direct communication with subsistence 
fishers/hunters during the surveys. Considering the limited time that 
the planned seismic surveys would take place and the far offshore 
location of the surveys, no direct interaction with subsistence 
fishers/hunters would be anticipated. However, UAGI will still be 
required to remain in constant communication with subsistence fishers/
hunters during the surveys.
    Based on the description of the specified activity, the measures 
described to minimize adverse effects on the availability of marine 
mammals for subsistence purposes, and the proposed mitigation and 
monitoring measures, NMFS has preliminarily determined that there will 
not be an unmitigable adverse impact on subsistence uses from UAGI's 
proposed activities.

Endangered Species Act

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

Proposed Authorization

    As a result of these preliminary determinations, NMFS proposes to 
issue an IHA to UAGI for conducting geophysical surveys in the Arctic 
in August and September, 2021, provided the previously mentioned 
mitigation, monitoring, and reporting requirements are incorporated. A 
draft of the proposed IHA can be found at https://www.fisheries.noaa.gov/permit/incidental-take-authorizations-under-
marine-mammal-protection-act.

[[Page 28809]]

Request for Public Comments

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

    Dated: May 25, 2021.
Catherine Marzin,
Acting Director, Office of Protected Resources, National Marine 
Fisheries Service.
[FR Doc. 2021-11339 Filed 5-27-21; 8:45 am]
BILLING CODE 3510-22-P