[Federal Register Volume 86, Number 133 (Thursday, July 15, 2021)]
[Notices]
[Pages 37286-37309]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2021-15046]


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DEPARTMENT OF COMMERCE

National Oceanic and Atmospheric Administration

[RTID 0648-XB223]


Takes of Marine Mammals Incidental to Specified Activities; 
Taking Marine Mammals Incidental to a Geophysical Survey of the Queen 
Charlotte Fault

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

ACTION: Notice; issuance of incidental harassment authorization.

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SUMMARY: In accordance with the regulations implementing the Marine 
Mammal Protection Act (MMPA) as amended, notification is hereby given 
that NMFS has issued an incidental harassment authorization (IHA) to 
the Lamont-Doherty Earth Observatory of Columbia University (L-DEO) to 
incidentally harass marine mammals

[[Page 37287]]

during a marine geophysical survey of the Queen Charlotte Fault in the 
Northeast Pacific Ocean.

DATES: The authorization is effective for a period of one year, from 
July 9, 2021, through July 8, 2022.

FOR FURTHER INFORMATION CONTACT: Ben Laws, Office of Protected 
Resources, NMFS, (301) 427-8401.

SUPPLEMENTARY INFORMATION:

Availability

    Electronic copies of the application and supporting documents, as 
well as a list of the references cited in this document, may be 
obtained online at: www.fisheries.noaa.gov/action/incidental-take-authorization-lamont-doherty-earth-observatory-geophysical-survey-queen. In case of problems accessing these documents, please call the 
contact listed above.

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 mitigation, 
monitoring and reporting of the takings are set forth. The definitions 
of all applicable MMPA statutory terms cited above are included in the 
relevant sections below.

Summary of Request

    On December 3, 2019, NMFS received a request from L-DEO for an IHA 
to take marine mammals incidental to a geophysical survey of the Queen 
Charlotte Fault (QCF) off of Alaska and British Columbia, Canada. L-DEO 
submitted a revised version of the application on April 2, 2020. On 
April 10, 2020, L-DEO informed NMFS that the planned survey would be 
deferred to 2021 as a result of issues related to the COVID-19 
pandemic. L-DEO subsequently submitted revised versions of the 
application on October 22 and December 16, 2020, the latter of which 
was deemed adequate and complete. A final, revised version was 
submitted on January 11, 2021. L-DEO's request is for take of 21 
species of marine mammals by Level B harassment. In addition, NMFS 
proposes to authorize take by Level A harassment for seven of these 
species.

Description of Proposed Activity

Overview

    Researchers from L-DEO, the University of New Mexico, and Western 
Washington University, with funding from NSF, plan to conduct a high-
energy seismic survey from the Research Vessel (R/V) Marcus G. Langseth 
(Langseth) at the QCF in the northeast Pacific Ocean during late summer 
2021. Other research collaborators include Dalhousie University, the 
Geological Survey of Canada, and the U.S. Geological Survey. The two-
dimensional (2-D) seismic survey will occur within the Exclusive 
Economic Zones (EEZ) of the United States and Canada, including in 
Canadian territorial waters. The survey will use a 36-airgun towed 
array with a total discharge volume of ~6,600 cubic inches (in\3\) as 
an acoustic source, acquiring return signals using both a towed 
streamer as well as ocean bottom seismometers (OBSs).
    The study will use 2-D seismic surveying to characterize crustal 
and uppermost mantle velocity structure, fault zone architecture and 
rheology, and seismicity of the QCF. The QCF system is an approximately 
1,200 kilometer (km)-long onshore-offshore transform system connecting 
the Cascadia and Alaska-Aleutian subduction zones; the QCF is the 
approximately 900 km-long offshore component of the transform system. 
The purpose of the study is to characterize an approximately 450-km 
segment of the fault that encompasses systematic variations in key 
parameters in space and time: (1) changes in fault obliquity relative 
to Pacific-North American plate motion leading to increased convergence 
from north to south; (2) Pacific plate age and theoretical mechanical 
thickness decrease from north to south; and (3) a shift in Pacific 
plate motion at approximately 12-6 million years ago that may have 
increased convergence along the entire length of the fault, possibly 
initiating underthrusting in the southern portion of the study area. 
Current understanding of how these variations are expressed through 
seismicity, crustal-scale deformation, and lithospheric structure and 
dynamics is limited due to lack of instrumentation and modern seismic 
imaging.

Dates and Duration

    The survey is expected to last for approximately 36 days, including 
approximately 27 days of seismic operations, 3 days of equipment 
deployment/retrieval, 2 days of transits, and 4 contingency days 
(accounting for potential delays due to, e.g., weather). R/V Langseth 
will likely leave out of and return to port in Ketchikan, Alaska, 
during July-August 2021.

Specific Geographic Region

    The survey will occur within the area of approximately 52-57[deg] N 
and approximately 131-137[deg] W. Representative survey tracklines are 
shown in Figure 1. Some deviation in actual 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. The survey will occur 
within the EEZs of the United States and Canada, including Alaskan 
state waters and Canadian territorial waters, ranging in depth from 50-
2,800 meters (m). Approximately 4,250 km of transect lines will be 
surveyed, with 13 percent of the transect lines in Canadian territorial 
waters. Most of the survey (69 percent) will occur in deep water 
(>1,000 m), 30 percent will occur in intermediate water (100-1,000 m 
deep), and approximately 1 percent will take place in shallow water 
<100 m deep.
    Note that the MMPA does not apply in Canadian territorial waters. 
L-DEO is subject only to Canadian law in conducting that portion of the 
survey. However, NMFS has calculated the expected level of incidental 
take in the entire activity area (including Canadian territorial 
waters) as part of the analysis supporting our determination under the 
MMPA that the activity will have a negligible impact on the affected 
species (see Estimated Take and Negligible Impact Analysis and 
Determination).
BILLING CODE 3510-22-P

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[GRAPHIC] [TIFF OMITTED] TN15JY21.104


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BILLING CODE 3510-22-C

Detailed Description of Specific Activity

    The procedures to be used for the survey will be similar to those 
used during previous seismic surveys by L-DEO and will use conventional 
seismic methodology. The survey will involve one source vessel, the R/V 
Langseth. R/V Langseth will deploy an array of 36 airguns as an energy 
source with a total volume of 6,600 cubic inches (in\3\). The array 
consists of 36 elements, including 20 Bolt 1500LL airguns with volumes 
of 180 to 360 in\3\ and 16 Bolt 1900LLX airguns with volumes of 40 to 
120 in\3\. The airgun array configuration is illustrated in Figure 2-11 
of NSF and USGS's Programmatic Environmental Impact Statement (PEIS; 
NSF-USGS, 2011). (The PEIS is available online at: www.nsf.gov/geo/oce/envcomp/usgs-nsf-marine-seismic-research/nsf-usgs-final-eis-oeis-with-appendices.pdf). The vessel speed during seismic operations will be 
approximately 4.2 knots (kn) (~7.8 km/hour) during the survey and the 
airgun array will be towed at a depth of 12 m. The receiving system 
will consist of OBSs and a towed hydrophone streamer with a nominal 
length of 15 km (OBS and multi-channel seismic (MCS) shooting). As the 
airguns are towed along the survey lines, the hydrophone streamer will 
transfer the data to the on-board processing system, and the OBSs will 
receive and store the returning acoustic signals internally for later 
analysis.
    Approximately 60 short-period OBSs will be deployed and 
subsequently retrieved at a total of 123 sites in multiple phases from 
a second vessel, the Canadian Coast Guard ship John P. Tully (CCGS 
Tully). Along OBS refraction lines, OBSs will be deployed by CCGS Tully 
at 10 km intervals, with a spacing of 5 km over the central 40 km of 
the fault zone for fault-normal crossings. Twenty-eight broadband OBS 
instruments will also collect data during the survey and will be 
deployed prior to the active-source seismic survey, depending on 
logistical constraints. When an OBS is ready to be retrieved, an 
acoustic release transponder (pinger) interrogates the instrument at a 
frequency of 8-11 kilohertz (kHz); a response is received at 11.5-13 
kHz. The burn-wire release assembly is then activated, and the 
instrument is released from its 80-kg anchor to float to the surface. 
Take of marine mammals is not expected to occur incidental to L-DEO's 
use of OBSs.
    The airguns will fire at a shot interval of 50 m (approximately 23 
seconds (s)) during MCS shooting with the hydrophone streamer 
(approximately 42 percent of survey effort), at a 150-m interval 
(approximately 69 s) during refraction surveying to OBSs (approximately 
29 percent of survey effort), and at a shot interval of every minute 
(approximately 130 m) during turns (approximately 29 percent of survey 
effort).
    Short-period OBSs will be deployed first along five OBS refraction 
lines by CCGS Tully. Two OBS lines run parallel to the coast, and three 
are perpendicular to the coast; one perpendicular line is located off 
Southeast Alaska, one is off Haida Gwaii, British Columbia, and another 
is located in Dixon Entrance. Please see Figure 1 for all location 
references. Following refraction shooting of a single line, short-
period instruments on that line will be recovered, serviced, and 
redeployed on a subsequent refraction line while MCS data will be 
acquired by the Langseth. MCS lines will be acquired off Southeast 
Alaska, Haida Gwaii, and Dixon Entrance. The coast-parallel OBS 
refraction transect nearest to shore will only be surveyed once at OBS 
shot spacing. The other coast-parallel OBS refraction transect (on the 
ocean side) will be acquired twice, once during refraction and once 
during reflection surveys. In addition, portions of the three coast-
perpendicular OBS refraction lines will also be surveyed twice, once 
for OBS shot spacing and once for MCS shot spacing. The coincident 
reflection/refraction profiles that run parallel to the coast will be 
acquired in multiple segments to ensure straight-line geometry. 
Sawtooth transits during which seismic data will be acquired will take 
place between transect lines when possible; otherwise, boxcar turns 
will be performed to save time. Both reflection and refraction surveys 
will use the same airgun array with the same discharge volume. There 
could be additional seismic operations associated with turns, airgun 
testing, and repeat coverage of any areas where initial data quality is 
sub-standard, and 25 percent has been added to the assumed survey line-
kms to account for this potential.
    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) will be operated from R/V Langseth 
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 the other sources' characteristics (e.g., narrow 
downward-directed beam), marine mammals would experience no more than 
one or two brief ping exposures from them, if any exposure were to 
occur. No take of marine mammals is expected to occur incidental to the 
use of these sources, regardless of whether they are used in 
conjunction with the airgun array. Required mitigation, monitoring, and 
reporting measures are described in detail later in this document 
(please see Mitigation and Monitoring and Reporting).

Comments and Responses

    A notice of proposed IHA was published in the Federal Register on 
June 4, 2021 (86 FR 30006). During the 30-day public comment period, 
NMFS did not receive any substantive public comments.

Changes From the Proposed IHA

    The primary change from the proposed IHA is the addition of take 
authorization for the North Pacific right whale. In the notice of 
proposed IHA, we described available information regarding North 
Pacific right whale occurrence in the survey region and determined that 
encounter was unlikely and that authorization of take was not 
warranted. Following publication of the notice of proposed IHA, on 
approximately June 15, 2021, a North Pacific right whale was observed 
in Canadian waters off Haida Gwaii during survey effort by the 
Department of Fisheries and Oceans Canada (Kloster, 2021). As a result, 
NMFS has authorized North Pacific right whale take, as described in 
greater detail in Estimated Take, given the potential for a repeat 
encounter during L-DEO's survey.
    In addition, we rectify an error in the estimated take of Steller 
sea lions occurring within Canadian territorial waters. Estimates of 
take that may occur within foreign territorial waters are not 
authorized under the MMPA, but are considered in making a finding of 
negligible impact on the affected species or stocks. In this case, we 
incorrectly applied a density value to L-DEO survey effort in deep 
water, when in fact the density of Steller sea lions in the deep depth 
stratum is correctly assumed to be zero (DoN, 2021). Through correction 
of this error, the estimated take of Steller sea lions in Canadian

[[Page 37290]]

territorial waters is revised from 2,522 to 2,278. Please see Table 7.

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' Stock Assessment Reports (SARs; 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' website 
(www.fisheries.noaa.gov/find-species).
    Table 1 lists all species with expected potential for occurrence in 
the survey area 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 (2021). PBR is defined by 
the MMPA as the maximum number of animals, not including natural 
mortalities, that may be removed from a marine mammal stock while 
allowing that stock to reach or maintain its optimum sustainable 
population (as described in NMFS's SARs). While no 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' stock abundance estimates for most species represent the total 
estimate of individuals within the geographic area, if known, that 
comprises that stock. For some species, this geographic area may extend 
beyond U.S. waters. All managed stocks in this region are assessed in 
NMFS' U.S. Pacific and Alaska SARs. All MMPA stock information 
presented in Table 1 is the most recent available at the time of 
publication and is available in the 2019 SARs (Caretta et al., 2020; 
Muto et al., 2020) and draft 2020 SARs (available online at: 
www.fisheries.noaa.gov/national/marine-mammal-protection/draft-marine-mammal-stock-assessment-reports). Where available, abundance and status 
information is also presented for marine mammals in British Columbia 
waters. Twenty-two species (with 29 managed stocks) are considered to 
have the potential to occur in the survey area.

                                               Table 1--Marine Mammals That Could Occur in the Survey Area
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                                                                                  ESA/MMPA       Stock abundance
                                                                                   status;       (CV, Nmin, most        British                Annual M/
           Common name                Scientific name            Stock         strategic  (Y/    recent abundance      Columbia        PBR       SI \4\
                                                                                   N) \1\          survey) \2\       abundance \3\
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                          Order Cetartiodactyla--Cetacea--Superfamily Mysticeti (baleen whales)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Family Balaenidae:
    North Pacific right whale....  Eubalaena japonica..  Eastern North         E/D; Y          31 (0.226; 26;       ..............       0.05          0
                                                          Pacific (ENP).                        2008).
Family Eschrichtiidae:
    Gray whale...................  Eschrichtius          Eastern North         -; N            26,960 (0.05;        ..............        801        131
                                    robustus.             Pacific (ENP) *.                      25,849; 2016).
                                                         Western North         E/D; Y          290 (n/a; 271;       ..............       0.12        Unk
                                                          Pacific (WNP)*.                       2016).
Family Balaenopteridae
 (rorquals):
    Humpback whale...............  Megaptera             Central North         E/D; Y          10,103 (0.3; 7,891;           1,029         83         26
                                    novaeangliae kuzira.  Pacific (CNP) *.                      2006).
    Minke whale..................  Balaenoptera          Alaska *............  -; N            Unknown............             522     Undet.          0
                                    acutorostrata
                                    scammoni.
    Sei whale....................  B. borealis borealis  ENP.................  E/D; Y          519 (0.4; 374;       ..............       0.75      >=0.2
                                                                                                2014).
    Fin whale....................  B. physalus physalus  Northeast Pacific *.  E/D; Y          Unknown............             329     Undet.        0.6
    Blue whale...................  B. musculus musculus  ENP.................  E/D; Y          1,496 (0.44; 1,050;  ..............    \7\ 1.2     >=19.4
                                                                                                2014).
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                                            Superfamily Odontoceti (toothed whales, dolphins, and porpoises)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Family Physeteridae:
    Sperm whale..................  Physeter              North Pacific *.....  E/D; Y          Unknown............  ..............     Undet.        3.5
                                    macrocephalus.
Family Ziphiidae (beaked whales):
    Cuvier's beaked whale........  Ziphius cavirostris.  Alaska *............  -; N            Unknown............  ..............     Undet.          0
    Baird's beaked whale.........  Berardius bairdii...  Alaska *............  -; N            Unknown............  ..............     Undet.          0
    Stejneger's beaked whale.....  Mesoplodon            Alaska *............  -; N            Unknown............  ..............     Undet.          0
                                    stejnegeri.
Family Delphinidae:
    Pacific white-sided dolphin..  Lagenorhynchus        North Pacific \6\...  -; N            26,880 (n/a;                 22,160     Undet.          0
                                    obliquidens.                                                26,880; 1990).
    Northern right whale dolphin.  Lissodelphis          CA/OR/WA............  -; N            26,556 (0.44;        ..............        179        3.8
                                    borealis.                                                   18,608; 2014).
    Risso's dolphin..............  Grampus griseus.....  CA/OR/WA............  -; N            6,336 (0.32; 4,817;  ..............         46      >=3.7
                                                                                                2014).
    Killer whale.................  Orcinus orca \5\....  ENP Offshore........  -; N            300 (0.1; 276;                  371        2.8          0
                                                                                                2012).
                                                         ENP Gulf of Alaska,   -; N            587 (n/a; 2012)....                        5.9        0.8
                                                          Aleutian Islands,
                                                          and Bering Sea
                                                          Transient.
                                                         ENP West Coast        -; N            349 (n/a; 2018)....                        3.5        0.4
                                                          Transient.
                                                         ENP Alaska Resident.  -; N            2,347 (n/a; 2012)..                         24          1
                                                         Northern Resident...  -; N            302 (n/a; 2018)....                        2.2        0.2

[[Page 37291]]

 
Family Phocoenidae (porpoises):
    Harbor porpoise..............  Phocoena phocoena     Southeast Alaska *..  -; Y            Unknown............           8,091     Undet.         34
                                    vomerina.
    Dall's porpoise..............  Phocoenoides dalli    Alaska \6\..........  -; N            83,400 (0.097; n/a;           5,303     Undet.         38
                                    dalli.                                                      1991).
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                                                         Order Carnivora--Superfamily Pinnipedia
--------------------------------------------------------------------------------------------------------------------------------------------------------
Family Otariidae (eared seals and
 sea lions):
    Northern fur seal............  Callorhinus ursinus.  Pribilof Islands/     D; Y            608,143 (0.2;        ..............     11,067        387
                                                          Eastern Pacific.                      514,738; 2018).
    California sea lion..........  Zalophus              United States.......  -/-; N          257,606 (N/A,        ..............     14,011      >=321
                                    californianus.                                              233,515, 2014).
    Steller sea lion.............  Eumetopias jubatus    Western U.S. *......  E/D; Y          52,932 (n/a; 2019).          15,348        318        255
                                    jubatus.
                                   E. j. monteriensis..  Eastern U.S. *......  -/-; N          43,201 (n/a; 2017).  ..............      2,592        112
Family Phocidae (earless seals):
    Harbor seal..................  Phoca vitulina        Sitka/Chatham Strait  -; N            13,289 (n/a;                 24,916        356         77
                                    richardii.                                                  11,883; 2015).
                                                         Dixon/Cape Decision.  -; N            23,478 (n/a;                               644         69
                                                                                                21,453; 2015).
                                                         Clarence Strait.....  -; N            27,659 (n/a;                               746         40
                                                                                                24,854; 2015).
    Northern elephant seal.......  Mirounga              California Breeding.  -; N            179,000 (n/a;        ..............      4,882        8.8
                                    angustirostris.                                             81,368; 2010).
--------------------------------------------------------------------------------------------------------------------------------------------------------
 *Stocks marked with an asterisk were addressed in further detail in the notice of proposed IHA (86 FR 30006; June 4, 2021).
\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 at: www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessments. 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\ Total abundance estimates for animals in British Columbia based on surveys of the Strait of Georgia, Johnstone Strait, Queen Charlotte Sound, Hecate
  Strait, and Dixon Entrance. This column represents estimated abundance of animals in British Columbia, where available, but does not necessarily
  represent additional stocks. Please see Best et al. (2015) and Pitcher et al. (2007) for additional information.
\4\ 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, subsistence hunting, ship strike). Annual M/SI often cannot be determined precisely and is in some cases presented as a minimum
  value. All M/SI values are as presented in the draft 2020 SARs.
\5\ Transient and resident killer whales are considered unnamed subspecies (Committee on Taxonomy, 2020).
\6\ 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 represent the best available
  information for use in this document.
\7\ This stock is known to spend a portion of time outside the U.S. EEZ. Therefore, the PBR presented here is the allocation for U.S. waters only and is
  a portion of the total. The total PBR for blue whales is 2.1 (7/12 allocation for U.S. waters). Annual M/SI presented for these species is for U.S.
  waters only.

    Table 1 denotes the status of species and stocks under the U.S. 
MMPA and ESA. We note also that under Canada's Species at Risk Act, the 
sei whale and blue whale are listed as endangered; the fin whale and 
northern resident, offshore, and transient populations of killer whales 
are listed as threatened; and the humpback whale, harbor porpoise, and 
Steller sea lion are considered species of special concern.
    The North Pacific right whale historically occurred across the 
North Pacific Ocean in subpolar to temperate waters, including waters 
off the coast of British Columbia (Scarff, 1986; Clapham et al., 2004). 
Sightings of this endangered species are now extremely rare, occurring 
primarily in the Okhotsk Sea and the eastern Bering Sea (Brownell et 
al., 2001; Shelden et al., 2005; Wade et al., 2006; Zerbini et al., 
2010). The summer range of the eastern North Pacific stock includes the 
Gulf of Alaska (GOA) and the Bering Sea, while the winter calving 
grounds remain unknown. Sightings in GOA are extremely rare. During 
three separate marine mammal surveys in the northern GOA from 2013-
2019, including one dedicated to right whales, right whales were 
acoustically detected off Kodiak Island but were not visually observed 
(Muto et al., 2020).
    In 2013, two North Pacific right whale sightings were made off the 
coast of British Columbia (U.S. Department of the Navy, 2015), 
representing the first sightings in Canadian waters since the 1950s. 
Individual sightings in Canadian waters were subsequently recorded in 
2018 and 2020 (Muto et al., 2020). There have also been four sightings, 
each of a single North Pacific right whale, in California waters within 
approximately the last 30 years (most recently in 2017) (Carretta et 
al., 1994; Brownell et al., 2001; Price, 2017). This historical paucity 
of sightings in the region led NMFS to conclude that there would be a 
very low probability of encountering this species in the action area 
and, therefore, that take should not be proposed for authorization. 
However, following the June 2021 sighting of a single right whale in 
Canadian waters discussed above, we have determined that an encounter 
could occur and, therefore, that take should be authorized. This 
sighting, and the subsequent decision to authorize take, is not 
necessarily inconsistent with the analysis presented in the notice of

[[Page 37292]]

proposed authorization. Rather, this sighting is consistent with the 
recent historical record of infrequent, unpredictable occurrence in the 
region. The fact that this most recent sighting has occurred within the 
survey area and nearly contemporaneous with the planned survey means 
that there is some heightened potential for encounter that should be 
considered in authorizing take that may occur incidental to the survey 
activity. See Estimated Take for additional discussion.
    Two populations of gray whales are recognized, eastern and western 
North Pacific (ENP and WNP). WNP whales are known to feed in the 
Okhotsk Sea and off of Kamchatka before migrating south to poorly known 
wintering grounds, possibly in the South China Sea. The two populations 
have historically been considered geographically isolated from each 
other; however, data from satellite-tracked whales indicate that there 
is some overlap between the stocks. Two WNP whales were tracked from 
Russian foraging areas along the Pacific rim to Baja California (Mate 
et al., 2011), and, in one case where the satellite tag remained 
attached to the whale for a longer period, a WNP whale was tracked from 
Russia to Mexico and back again (IWC, 2012). A number of whales are 
known to have occurred in the eastern Pacific through comparisons of 
ENP and WNP photo-identification catalogs (IWC, 2012; Weller et al., 
2011; Burdin et al., 2011). Therefore, a portion of the WNP population 
is assumed to migrate, at least in some years, to the eastern Pacific 
during the winter breeding season. Based on guidance provided through 
interagency consultation under section 7 of the ESA, approximately 0.1 
percent of gray whales occurring in southeast Alaska and northern 
British Columbia are likely to be from the Western North Pacific stock; 
the rest would be from the Eastern North Pacific stock.
    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 and 
shown in Table 1.
    In the eastern North Pacific, three humpback whale DPSs may occur: 
the Hawaii DPS (not listed), Mexico DPS (threatened), and Central 
America DPS (endangered). Individuals encountered in the proposed 
survey area would likely be from the Hawaii DPS, followed by the Mexico 
DPS; individuals from the Central America DPS are unlikely to feed in 
northern British Columbia and Southeast Alaska (Ford et al., 2014). 
According to Wade (2017), in southeast Alaska and northern British 
Columbia, encountered whales are most likely to be from the Hawaii DPS 
(96.1 percent), but could be from the Mexico DPS (3.8 percent).
    Additional detailed information regarding the potentially affected 
stocks of marine mammals was provided in the notice of proposed IHA (86 
FR 30006; June 4, 2021). No new information is available, and we do not 
reprint that discussion here. Please see the notice of proposed IHA for 
additional information.

Important Habitat

    Several biologically important areas (BIA) for marine mammals are 
recognized in southeast Alaska, and critical habitat is designated in 
southeast Alaska for the Steller sea lion (58 FR 45269; August 27, 
1993) and the Mexico DPS of humpback whale (86 FR 21082; April 21, 
2021). Note that although the eastern DPS of Steller sea lion was 
delisted in 2013, the change in listing status does not affect the 
designated critical habitat. Critical habitat is defined by section 3 
of the ESA as (1) the specific areas within the geographical area 
occupied by the species, at the time it is listed, on which are found 
those physical or biological features (a) essential to the conservation 
of the species and (b) which may require special management 
considerations or protection; and (2) specific areas outside the 
geographical area occupied by the species at the time it is listed, 
upon a determination by the Secretary that such areas are essential for 
the conservation of the species.
    Mexico DPS humpback whale critical habitat includes marine waters 
in Washington, Oregon, California, and Alaska. Only the areas 
designated in southeast Alaska fall within the survey area. The 
relevant designated critical habitat (Unit 10) extends from 139[deg]24' 
W, southeastward to the U.S. border with Canada. The area also extends 
offshore to a boundary drawn along the 2,000-m isobath. The essential 
feature for Mexico DPS humpback whale critical habitat is prey species, 
primarily euphausiids and small pelagic schooling fishes of sufficient 
quality, abundance, and accessibility within humpback whale feeding 
areas to support feeding and population growth. This area was drawn to 
encompass well-established feeding grounds in southeast Alaska and an 
identified feeding BIA (86 FR 21082; April 21, 2021). Humpback whales 
occur year-round in this unit, with highest densities occurring in 
summer and fall (Baker et al., 1985, 1986).
    Critical habitat for humpback whales has been designated under 
Canadian law in four locations in British Columbia (DFO, 2013), 
including in the waters of the survey area off Haida Gwaii (Langara 
Island and Southeast Moresby Island). These areas show persistent 
aggregations of humpback whales and have features such as prey 
availability, suitable acoustic environment, water quality, and 
physical space that allow for feeding, foraging, socializing, and 
resting (DFO, 2013).
    Designated Steller sea lion critical habitat includes terrestrial, 
aquatic, and air zones that extend 3,000 ft (0.9 km) landward, seaward, 
and above each major rookery and major haul-out in Alaska. Within the 
survey area, critical habitat is located on islands off the coast of 
southeast Alaska (e.g., Sitka, Coronation Island, Noyes Island, and 
Forrester Island). The physical and biological features identified for 
the aquatic areas of Steller sea lion designated critical habitat that 
occur within the survey area are those that support foraging, such as 
adequate prey resources and available foraging habitat. The proposed 
survey tracklines do not directly overlap any areas of Steller sea lion 
critical habitat, though the extent of the estimated ensonified area 
associated with the survey would overlap with units of Steller sea lion 
critical habitat. However, the brief duration of ensonification for any 
critical habitat unit leads us to conclude that any impacts on Steller 
sea lion habitat would be insignificant and would not affect the 
conservation value of the critical habitat.
    For humpback whales, seasonal feeding BIAs for spring (March-May), 
summer (June-August), and fall (September-November) are recognized in 
southeast Alaska (Ferguson et al., 2015). It should be noted that the 
aforementioned designated critical habitat in the survey area was based 
in large part on the same information that informed an understanding of 
the BIAs. Though the BIAs are not synonymous with critical habitat 
designated under the ESA, they were regarded by the humpback whale 
critical habitat review team as an important source of information and 
informative to their review of areas that meet the definition of 
critical habitat for humpback whales (86 FR 21082; April 21, 2021). The 
aforementioned southeast Alaska unit of designated critical habitat 
encompasses the BIAs, with the offshore and

[[Page 37293]]

nearshore boundaries corresponding with the BIA boundary.
    A separate feeding BIA is recognized in southeast Alaska for gray 
whales. Once considered only a migratory pathway, the Gulf of Alaska is 
now known to provide foraging and overwintering habitat for ENP gray 
whales (Ferguson et al., 2015). Based on the regular occurrence of 
feeding gray whales (including repeat sightings of individuals across 
years) off southeast Alaska, an area off of Sitka is recognized. The 
greatest densities of gray whales on the feeding area in southeast 
Alaska occur from May to November. However, this area is located to the 
north of the proposed survey area and would not be expected to be 
meaningfully impacted by the survey activities. A separate migratory 
BIA is recognized as extending along the continental shelf throughout 
the Gulf of Alaska. During their annual migration, most gray whales 
pass through the Gulf of Alaska in the fall (November through January; 
southbound) and again in the spring (March through May; northbound) 
(Ferguson et al., 2015). Therefore, the planned survey would not be 
expected to impact gray whale migratory habitat due to the timing of 
the survey in late summer. No important behaviors of gray whales in 
either the feeding or migratory BIAs are expected to be affected. For 
more information on BIAs, please see Ferguson et al. (2015) or visit 
https://oceannoise.noaa.gov/biologically-important-areas.

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. There is a currently 
ongoing UME affecting gray whales throughout their migratory range.
    Since January 1, 2019, elevated gray whale strandings have occurred 
along the west coast of North America from Mexico through Alaska. As of 
July 1, 2021, there have been a total of 480 whales reported in the 
event, with approximately 225 dead whales in Mexico, 237 whales in the 
United States (70 in California; 11 in Oregon; 55 in Washington, 101 in 
Alaska), and 18 whales in British Columbia, Canada. For the United 
States, the historical 18-year 5-month average (Jan-May) is 14.8 whales 
for the four states 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.
    Another recent, notable UME involved large whales and occurred in 
the western Gulf of Alaska and off of British Columbia, Canada. 
Beginning in May 2015, elevated large whale mortalities (primarily fin 
and humpback whales) occurred in the areas around Kodiak Island, 
Afognak Island, Chirikof Island, the Semidi Islands, and the southern 
shoreline of the Alaska Peninsula. Although most carcasses have been 
non-retrievable as they were discovered floating and in a state of 
moderate to severe decomposition, the UME is likely attributable to 
ecological factors, i.e., the 2015 El Ni[ntilde]o, ``warm water blob,'' 
and the Pacific Coast domoic acid bloom. The UME was closed in 2016. 
More information is available online at www.fisheries.noaa.gov/national/marine-life-distress/2015-2016-large-whale-unusual-mortality-event-western-gulf-alaska.

Marine Mammal Hearing

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

           Table 2--Marine Mammal Hearing Groups (NMFS, 2018)
------------------------------------------------------------------------
            Hearing group                 Generalized hearing range *
------------------------------------------------------------------------
Low-frequency (LF) cetaceans (baleen  7 Hz to 35 kHz.
 whales).
Mid-frequency (MF) cetaceans          150 Hz to 160 kHz.
 (dolphins, toothed whales, beaked
 whales, bottlenose whales).
High-frequency (HF) cetaceans (true   275 Hz to 160 kHz.
 porpoises, Kogia, river dolphins,
 cephalorhynchid, Lagenorhynchus
 cruciger & 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,

[[Page 37294]]

especially in the higher frequency range (Hemil[auml] et al., 2006; 
Kastelein et al., 2009; Reichmuth and Holt, 2013).
    For more detail concerning these groups and associated frequency 
ranges, please see NMFS (2018) for a review of available information. 
Twenty-two marine mammal species (17 cetacean and 5 pinniped (3 otariid 
and 2 phocid) species) are considered herein. Of the cetacean species 
that may be present, seven are classified as low-frequency cetaceans 
(i.e., all mysticete species), eight are classified as mid-frequency 
cetaceans (i.e., all delphinid and ziphiid species and the sperm 
whale), and two are classified as high-frequency cetaceans (i.e., 
porpoises).

Potential Effects of Specified Activities on Marine Mammals and Their 
Habitat

    This section includes a summary of the ways that L-DEO'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 L-DEO's activity. The Negligible Impact 
Analysis and Determination section considers the potential effects of 
the specified activity, the Estimated Take section, and the 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. The notice of proposed IHA (86 FR 30006; June 4, 
2021) provided a discussion and background information regarding active 
acoustic sound sources and acoustic terminology, which is not repeated 
here. Please see that notice for additional information.

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).
    Due to the characteristics of airgun arrays as a distributed sound 
source, maximum estimated Level A harassment isopleths for species of 
certain hearing groups are assumed to fall within the near field of the 
array. For these species, i.e., mid-frequency cetaceans and all 
pinnipeds, animals in the vicinity of L-DEO's proposed seismic survey 
activity are unlikely to incur PTS. For low-frequency cetaceans and 
high-frequency cetaceans, potential exposures sufficient to cause low-
level PTS may occur on the basis of cumulative exposure level and 
instantaneous exposure to peak pressure levels, respectively. However, 
when considered in conjunction with the potential for aversive 
behavior, relative motion of the exposed animal and the sound source, 
and the anticipated efficacy of the proposed mitigation requirements, a 
reasonable conclusion may be drawn that PTS is not a likely outcome for 
any species. However, we propose to authorize take by Level A 
harassment, where indicated by the quantitative exposure analysis, for 
species from the low- and high-frequency cetacean hearing groups. 
Please see Estimated Take and 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 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).

[[Page 37295]]

    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 3 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 kn. 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 L-DEO's specified survey activity are 
expected to be limited to Level B harassment consisting of behavioral 
harassment and/or temporary auditory effects and, for certain species 
of low- and high-frequency cetaceans only, low-level permanent auditory 
effects. No permanent auditory effects for any species belonging to 
other hearing groups, or significant impacts to marine mammal habitat, 
including prey, are expected.

Estimated Take

    This section provides an estimate of the number of incidental takes 
authorized through the 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 are primarily by Level B harassment, as use of 
seismic airguns has the potential to result in disruption of behavioral 
patterns for individual marine mammals. There is also some potential 
for auditory injury (Level A harassment) for mysticetes and high-
frequency cetaceans (i.e., porpoises). The mitigation and monitoring 
measures are expected to minimize the severity of such taking to the 
extent practicable.
    As described previously, no serious injury or mortality is 
anticipated or 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 take numbers.

Acoustic Thresholds

    NMFS uses 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--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), and the receiving animals (hearing, motivation, 
experience, demography, behavioral context) 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 of 160 dB re 1 
microPascal (root mean square) ([mu]Pa (rms)) for the impulsive sources 
(i.e., seismic airguns) evaluated here.
    Level A Harassment--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). L-DEO's 
seismic survey includes the use of impulsive (seismic airguns) sources.
    These thresholds are provided in the table 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 
www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-acoustic-technical-guidance.

[[Page 37296]]



                     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]Pa2s. 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 and other relevant information that will feed into identifying 
the area ensonified above the acoustic thresholds.
    L-DEO's modeling methodologies are described in greater detail in 
Appendix A of L-DEO's IHA application. The 2D survey will acquire data 
using the 36-airgun array with a total discharge volume of 6,600 in\3\ 
at a maximum tow depth of 12 m. L-DEO's modeling approach 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 
the 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 Langseth (array towed at 9 
m depth) 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 data (>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 the 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). Water depths in 
the project area may be up to 2,800 m, but marine mammals in the region 
are generally not anticipated to dive below 2,000 m (e.g., Costa and 
Williams, 1999). L-DEO typically derives estimated distances for 
intermediate water depths by applying a correction factor of 1.5 to the 
model results for deep water. In this case, the estimated radial 
distance for intermediate (100-1,000 m) and shallow (<100 m) water 
depths is taken from Crone et al. (2014), as these empirical data were 
collected in the same region as this survey. A correction factor of 
1.15 was applied to account for differences in array tow depth.
    The estimated distances to the Level B harassment isopleths for the 
array are shown in Table 4.

         Table 4--Predicted Radial Distances to Isopleths Corresponding to Level B Harassment Threshold
----------------------------------------------------------------------------------------------------------------
                                                                                                      Level B
                        Source and volume                          Tow depth (m)    Water depth     harassment
                                                                                        (m)          zone (m)
----------------------------------------------------------------------------------------------------------------
36 airgun array; 6,600 in\3\....................................              12           >1000       \1\ 6,733
                                                                                        100-1000       \2\ 9,468
                                                                                            <100      \2\ 12,650
----------------------------------------------------------------------------------------------------------------
\1\ Distance based on L-DEO model results.
\2\ Based on empirical data from Crone et al. (2014) with scaling.

    Predicted distances to Level A harassment isopleths, which vary 
based on marine mammal hearing groups, were calculated based on 
modeling performed by L-DEO 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 cumulative sound exposure level (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

[[Page 37297]]

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 for the Langseth 
airgun arrays 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. L-DEO used 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 for the Langseth's airgun array (modeled in 1 
Hz bands) was 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 information specific to the planned survey (i.e., the 
2.2 m/s source velocity and (worst-case) 23-s shot interval), potential 
radial distances to auditory injury zones were then calculated for 
SELcum thresholds.
    Inputs to the User Spreadsheets in the form of estimated source 
levels are shown in Appendix A of L-DEO's application. User 
Spreadsheets used by L-DEO 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        Otariids
--------------------------------------------------------------------------------------------------------------------------------------------------------
36-airgun array (6,600 in\3\)............  SELcum.......................             320               0               1              10               0
                                           Peak.........................              39              14             268              44              11
--------------------------------------------------------------------------------------------------------------------------------------------------------

    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, and NMFS continues to 
develop ways to quantitatively refine these tools and will 
qualitatively address the output where appropriate. For mobile sources, 
such as this seismic survey, the User 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 cetaceans, 
otariid pinnipeds, and phocid pinnipeds given very small modeled zones 
of injury for those species (all estimated zones less than 15 m for 
mid-frequency cetaceans and otariid pinnipeds, up to a maximum of 44 m 
for phocid pinnipeds), in context of distributed source dynamics. 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

[[Page 37298]]

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 peak isopleth distances 
would in all cases 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 peak SPL isopleth distances would not necessarily exist. 
In general, Caldwell and Dragoset (2000) suggest that the near-field 
for airgun arrays is considered to extend out to approximately 250 m. 
We provided additional discussion and quantitative support for this 
theoretical argument in the notice of proposed IHA. Please see that 
notice (86 FR 30006; June 4, 2021) for additional information.
    In consideration of the received sound levels in the near-field as 
described above, we expect the potential for Level A harassment of mid-
frequency cetaceans, otariid pinnipeds, 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. We do not believe that Level A harassment is a likely 
outcome for any mid-frequency cetacean, otariid pinniped, or phocid 
pinniped and do not authorize any Level A harassment for these species.

Marine Mammal Occurrence

    Information about the presence, density, and group dynamics of 
marine mammals that informs the take calculations was provided in our 
notice of proposed IHA (86 FR 30006; June 4, 2021). That information is 
not re-printed here. For additional detail, please see the notice of 
proposed IHA. Density values were provided in Table 6 of that notice. 
No new density information is available since we published the notice 
of proposed IHA, and no changes have been made. We relied largely upon 
the Navy's Marine Species Density Database (DoN, 2019, 2021), which is 
currently the most comprehensive compendium for density data available 
for the GOA and the only source of density data available for southeast 
Alaska.
    As described above in Changes from the Proposed IHA, the estimated 
take of Steller sea lions in Canadian territorial waters was incorrect. 
The correct density values were provided in Table 6 of the notice of 
proposed IHA; however, an erroneous density value was applied in 
producing the incorrect estimate provided in Table 8 of the notice of 
proposed IHA. That error has been corrected herein (see Table 7).

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 6. For additional details regarding calculations of ensonified 
area, please see Appendix D of L-DEO's application. As noted 
previously, L-DEO has added 25 percent in the form of operational days, 
which is equivalent to adding 25 percent to the line-kms to be 
surveyed. This accounts for the possibility that additional operational 
days are required, but likely results in an overestimate of actual 
exposures.
    For North Pacific right whales, the recent observation of an 
individual whale in Canadian waters where the survey will occur means 
that the potential for an encounter, while still unpredictable, is 
heightened. While we here assume that a North Pacific right whale 
encounter may occur, we also assume that such an event is unlikely 
(during two weeks of survey effort, the DFO researchers had a single 
encounter) and would occur no more than once during the survey. In 
order to determine the appropriate take number for authorization, we 
reviewed available information for North Pacific right whales. While 
most observations outside of typical habitat near Kodiak Island in the 
northern GOA and in the eastern Bering Sea have been of single 
individuals, the average group size during observations in more typical 
habitat is of two whales (Shelden et al., 2005; Waite et al., 2003; 
Wade et al., 2011; Muto et al., 2020). The assumption that an encounter 
will occur once, in conjunction with a conservative assumption that the 
encounter could be with an average group, supports a determination that 
authorization of two takes is appropriate as a precautionary approach 
to ensuring that potential effects to North Pacific right whales are 
evaluated and that unauthorized take is avoided. We also note that 
application of density data from the Navy's northern GOA Temporary 
Marine Activities Area would produce an estimate of two exposures. 
Although it is likely that this density information is not an accurate 
representation of North Pacific right whale occurrence off of southeast 
Alaska and British Columbia, this approach provides additional support 
for the authorization of two takes.
    As previously noted, NMFS cannot authorize incidental take under 
the MMPA that may occur within the territorial seas of foreign nations 
(from 0-12 nmi (22.2 km) from shore), as the MMPA does not apply in 
those waters. However, NMFS has still calculated the estimated level of 
incidental take in the entire activity area (including Canadian 
territorial waters) as part of the analysis supporting our 
determination under the MMPA that the activity will have a negligible 
impact on the affected species. The total estimated take in U.S. and 
Canadian waters is presented in Table 7 (see Negligible Impact Analysis 
and Determination).
    The estimated marine mammal exposures above harassment thresholds 
are generally assumed here to equate to take, and the estimates form 
the basis for our take authorization numbers. For the species for which 
NMFS does not expect there to be a reasonable potential for take by 
Level A harassment to occur, i.e., mid-frequency cetaceans and all 
pinnipeds, the estimated exposures above Level A harassment thresholds 
have been added to the estimated exposures above the Level B harassment 
threshold to produce a total number of incidents of take by Level B 
harassment that is authorized. Estimated exposures and take numbers for 
authorization are shown in Table 6. Regarding humpback whale take 
numbers, we assume that whales encountered will follow Wade (2017), 
i.e., that 96.1 percent of takes would accrue to the Hawaii DPS and 3.8 
percent to the Mexico DPS. Of the estimated take of gray whales, and 
based on guidance provided through interagency consultation under 
section 7 of the ESA, we assume that 0.1 percent of encountered whales 
would be from the WNP stock and authorize take accordingly. For Steller 
sea lions, 2.2 percent are assumed to belong to the western DPS 
(Hastings et al., 2020).

[[Page 37299]]



                                Table 6--Estimated Taking by Level A and Level B Harassment, and Percentage of Population
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                             Estimated       Estimated      Authorized      Authorized
              Species                       Stock             Level B         Level A         Level B         Level A       Total take      Percent of
                                                            harassment      harassment      harassment      harassment                       stock \1\
--------------------------------------------------------------------------------------------------------------------------------------------------------
North Pacific right whale \2\.....  ....................               2               0               2               0               2             6.1
Gray whale........................  WNP.................           1,450              45               2               0               2             0.7
                                    ENP.................                                           1,448              45           1,493             5.5
Humpback whale....................  ....................             403              14             403              14             417             4.1
Blue whale........................  ....................              31               1              31               1              32             2.1
Fin whale \3\.....................  ....................             873              44             873              44             917             n/a
Sei whale.........................  ....................              34               1              34               1              35             6.7
Minke whale \3\...................  ....................              57               2              57               2              59             n/a
Sperm whale \3\...................  ....................             131               0             131               0             131             n/a
Baird's beaked whale \3\..........  ....................              29               0              29               0              29             n/a
Stejneger's beaked whale \3\......  ....................             120               0             120               0             120             n/a
Cuvier's beaked whale \3\.........  ....................             114               0             114               0             114             n/a
Pacific white-sided dolphin.......  ....................           1,371               3           1,374               0           1,374             5.1
Northern right whale dolphin......  ....................             922               5             927               0             927             3.5
Risso's dolphin \4\...............  ....................               1               0              22               0              22             0.3
Killer whale......................  Offshore............             290               0             290               0             290            96.7
                                    GOA/BSAI Transient..  ..............  ..............  ..............  ..............  ..............            49.4
                                    WC Transient........  ..............  ..............  ..............  ..............  ..............            83.1
                                    AK Resident.........  ..............  ..............  ..............  ..............  ..............            12.4
                                    Northern Resident...  ..............  ..............  ..............  ..............  ..............            96.0
Dall's porpoise...................  ....................           5,661             178           5,661             178           5,839             7.0
Harbor porpoise...................  ....................             990              26             990              26           1,016             n/a
Northern fur seal.................  ....................           5,804               8           5,812               0           5,812             1.0
California sea lion...............  ....................           1,256               1           1,258               0           1,258             0.5
Steller sea lion..................  WDPS................           2,433               2              54               0              54             0.1
                                    EDPS................  ..............  ..............           2,381               0           2,381             5.5
Northern elephant seal............  ....................           6,811              39           6,850               0           6,850             3.8
Harbor seal.......................  Sitka/Chatham Strait           5,992              21           6,012               0           6,012            45.2
                                    Dixon/Cape Decision.  ..............  ..............  ..............  ..............  ..............            25.6
                                    Clarence Strait.....  ..............  ..............  ..............  ..............  ..............            21.7
--------------------------------------------------------------------------------------------------------------------------------------------------------
\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 takes occurred within each stock. Where necessary, additional discussion is provided in the Small Numbers section.
\2\ Take number represents qualitative consideration of likelihood of encounter, average group size, and available density information.
\3\ As noted in Table 1, there is no estimate of abundance available for these species.
\4\ Estimated exposure of one Risso's dolphin increased to group size of 22 (Barlow, 2016).

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 (latter not applicable for this action). 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. 
This considers the nature of the potential adverse impact being 
mitigated (likelihood, scope, range). It further considers the 
likelihood that the measure will be effective if implemented 
(probability of accomplishing the mitigating result if implemented as 
planned), the likelihood of effective implementation (probability 
implemented as planned); and
    (2) The practicability of the measures for applicant 
implementation, which may consider such things as cost, impact on 
operations, and, in the case of a military readiness activity, 
personnel safety, practicality of implementation, and impact on the 
effectiveness of the military readiness activity.
    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.

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 exclusion zone (EZ),

[[Page 37300]]

within which observation of certain marine mammals requires shutdown of 
the acoustic source, but also a buffer zone and, to the extent possible 
depending on conditions, the surrounding waters. 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-start 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 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). This 1,000-m zone (EZ 
plus buffer) represents the pre-start clearance zone. Visual monitoring 
of the EZ and adjacent waters 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-start 
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.
    L-DEO 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 and two of the acoustic PSOs (discussed 
below) aboard the vessel must have a minimum of 90 days at-sea 
experience working in those roles, respectively, 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 pre-start 
clearance zone must begin no less than 30 minutes prior to ramp-up, and 
monitoring 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.
    PSOs shall establish and monitor the exclusion and buffer zones. 
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. 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 4 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.

Passive Acoustic Monitoring

    Acoustic monitoring means the use of trained personnel (sometimes 
referred to as passive acoustic monitoring (PAM) operators, herein 
referred to as acoustic PSOs) to operate PAM equipment to acoustically 
detect the presence of marine mammals. Acoustic monitoring involves 
acoustically detecting marine mammals regardless of distance from the 
source, as localization of animals may not always be possible. Acoustic 
monitoring is intended to further support visual monitoring (during 
daylight hours) in maintaining an EZ around the sound source that is 
clear of marine mammals. In cases where visual monitoring is not 
effective (e.g., due to weather, nighttime), acoustic monitoring may be 
used to allow certain activities to occur, as further detailed below.
    PAM will take place in addition to the visual monitoring program. 
Visual monitoring typically is not effective during periods of poor 
visibility or at night, and even with good visibility, is unable to 
detect marine mammals when they are below the surface or beyond visual 
range. Acoustic monitoring can be used in addition to visual 
observations to improve detection, identification, and localization of 
cetaceans. The acoustic monitoring serves to alert visual PSOs (if on 
duty) when vocalizing cetaceans are detected. It is only useful when 
marine mammals vocalize, but it can be effective either by day or by 
night, and does not depend on good visibility. It will be monitored in 
real time so that the visual observers can be advised when cetaceans 
are detected.
    The R/V Langseth will use a towed PAM system, which must be 
monitored by at a minimum one on duty acoustic PSO beginning at least 
30 minutes prior to ramp-up and at all times during use of the acoustic 
source. Acoustic PSOs may be on watch for a maximum of 4 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 (acoustic and visual but not at same 
time) may not exceed 12 hours per 24-hour period for any individual 
PSO.
    Survey activity may continue for 30 minutes when the PAM system 
malfunctions or is damaged, while the PAM operator diagnoses the issue. 
If the diagnosis indicates that the PAM system must be repaired to 
solve the problem, operations may continue for an additional 5 hours 
without acoustic monitoring during daylight hours only under the 
following conditions:
     Sea state is less than or equal to BSS 4;
     No marine mammals (excluding delphinids) detected solely 
by PAM in

[[Page 37301]]

the applicable EZ in the previous 2 hours;
     NMFS is notified via email as soon as practicable with the 
time and location in which operations began occurring without an active 
PAM system; and
     Operations with an active acoustic source, but without an 
operating PAM system, do not exceed a cumulative total of 5 hours in 
any 24-hour period.

Establishment of Exclusion and Pre-Start Clearance 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 critical behaviors. The 
PSOs will establish a minimum EZ with a 500-m radius. The 500-m EZ will 
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). With certain exceptions (described below), if a marine mammal 
appears within or enters this zone, the acoustic source will be shut 
down.
    The pre-start clearance zone is defined as the area that must be 
clear of marine mammals prior to beginning ramp-up of the acoustic 
source, and includes the EZ plus the buffer zone. Detections of marine 
mammals within the pre-start clearance zone will prevent airgun 
operations from beginning (i.e., ramp-up).
    The 500-m EZ is intended to be precautionary in the sense that it 
would be expected to contain sound exceeding the injury criteria for 
all cetacean hearing groups, (based on the dual criteria of 
SELcum and peak sound pressure level (SPL)), while also 
providing a consistent, reasonably observable zone within which PSOs 
will typically be able to conduct effective observational effort. 
Additionally, a 500-m EZ is 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 500 m is likely regularly attainable for PSOs using the 
naked eye during typical conditions. The pre-start clearance zone 
simply represents the addition of a buffer to the EZ, doubling the EZ 
size during pre-clearance.
    An extended EZ of 1,500 m must be enforced for all beaked whales. 
No buffer of this extended EZ is required.

Pre-Start 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. The intent of pre-
start clearance observation (30 minutes) is to ensure no protected 
species are observed within the pre-clearance zone (or extended EZ, for 
beaked whales) prior to the beginning of ramp-up. During pre-start 
clearance period is the only time observations of marine mammals in the 
buffer zone would prevent operations (i.e., the beginning of ramp-up). 
The intent of ramp-up is to warn marine mammals 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-start 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 pre-start clearance zone 
(and extended EZ) for 30 minutes prior to the initiation of ramp-up 
(pre-start 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-start 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 exclusion or buffer zone. If a marine mammal is 
observed within the pre-start clearance zone (or extended EZ, for 
beaked whales) during the 30 minute pre-start 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 sperm 
whales, beaked whales, and large delphinids, such as 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. The operator must provide information to the PSO 
documenting that appropriate procedures were followed;
     PSOs must monitor the pre-start clearance zone (and 
extended EZ) during ramp-up, and ramp-up must cease and the source must 
be shut down upon detection of a marine mammal within the applicable 
zone. 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 have 
occurred within the applicable EZ. For any longer shutdown, pre-start 
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-start 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-start 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

[[Page 37302]]

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 both 
visual and acoustic PSOs are on duty, all detections will be 
immediately communicated to the remainder of the on-duty PSO team for 
potential verification of visual observations by the acoustic PSO or of 
acoustic detections by visual PSOs. When the airgun array is active 
(i.e., anytime one or more airguns is active, including during ramp-up) 
and (1) a marine mammal appears within or enters the applicable EZ and/
or (2) a marine mammal (other than delphinids, see below) is detected 
acoustically and localized within 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. Additionally, shutdown will occur 
whenever PAM alone (without visual sighting), confirms presence of 
marine mammal(s) in the EZ. If the acoustic PSO cannot confirm presence 
within the EZ, visual PSOs will be notified but shutdown is not 
required.
    Following a shutdown, airgun activity will 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 
(i.e., animal is not required to fully exit the buffer zone where 
applicable), or it has not been seen within the EZ for 15 minutes for 
small odontocetes and pinnipeds, or 30 minutes for all mysticetes and 
all other odontocetes, including sperm whales, beaked whales, and large 
delphinids, such as killer whales.
    The shutdown requirement can be waived for small dolphins if an 
individual is detected within the EZ. As defined here, the small 
dolphin group is intended to encompass those members of the Family 
Delphinidae most likely to voluntarily approach the source vessel for 
purposes of interacting with the vessel and/or airgun array (e.g., bow 
riding). This exception to the shutdown requirement applies solely to 
specific genera of small dolphins (Lagenorhynchus and Lissodelphis).
    We include this small dolphin exception because shutdown 
requirements for small dolphins under all circumstances represent 
practicability concerns without likely commensurate benefits for the 
animals in question. Small dolphins are generally the most commonly 
observed marine mammals in the specific geographic region and would 
typically be the only marine mammals likely to intentionally approach 
the vessel. As described above, auditory injury is extremely unlikely 
to occur for mid-frequency cetaceans (e.g., delphinids), as this group 
is relatively insensitive to sound produced at the predominant 
frequencies in an airgun pulse while also having a relatively high 
threshold for the onset of auditory injury (i.e., permanent threshold 
shift).
    A large body of anecdotal evidence indicates that small dolphins 
commonly approach vessels and/or towed arrays during active sound 
production for purposes of bow riding, with no apparent effect observed 
in those delphinoids (e.g., Barkaszi et al., 2012, 2018). The potential 
for increased shutdowns resulting from such a measure would require the 
Langseth to revisit the missed track line to reacquire data, resulting 
in an overall increase in the total sound energy input to the marine 
environment and an increase in the total duration over which the survey 
is active in a given area. Although other mid-frequency hearing 
specialists (e.g., large delphinids) are no more likely to incur 
auditory injury than are small dolphins, they are much less likely to 
approach vessels. Therefore, retaining a shutdown requirement for large 
delphinids would not have similar impacts in terms of either 
practicability for the applicant or corollary increase in sound energy 
output and time on the water. We do anticipate some benefit for a 
shutdown requirement for large delphinids in that it simplifies 
somewhat the total range of decision-making for PSOs and may preclude 
any potential for physiological effects other than to the auditory 
system as well as some more severe behavioral reactions for any such 
animals in close proximity to the source vessel.
    Visual PSOs shall use best professional judgment in making the 
decision to call for a shutdown if there is uncertainty regarding 
identification (i.e., whether the observed marine mammal(s) belongs to 
one of the delphinid genera for which shutdown is waived or one of the 
species with a larger EZ).
    L-DEO 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 a sperm whale or 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);
     An aggregation of six or more large whales; and/or
     A North Pacific right whale.

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 marine mammal. 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 duties must be provided sufficient 
training to (1) distinguish marine mammals from other phenomena and (2) 
broadly to identify a marine mammal as a right whale, other whale 
(defined in this context as sperm whales or baleen whales other than 
right whales), or other marine mammal.
    2. Vessel speeds must also be reduced to 10 kn 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 right whales. If a whale is observed but cannot be confirmed as a 
species other than a right whale, the vessel operator must assume that 
it is a right whale and take appropriate action.
    4. All vessels must maintain a minimum separation distance of 100 m 
from sperm whales and 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 marine mammals 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.

[[Page 37303]]

    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 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 required 
measures, as well as other measures considered by NMFS described above, 
NMFS has 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.

Mitigation Measures in Canadian Waters

    As stated previously, NMFS cannot authorize the incidental take of 
marine mammals in the territorial seas of foreign nations, as the MMPA 
does not apply in those waters. L-DEO is required to adhere to the 
mitigation measures described above while operating within the U.S. EEZ 
and Canadian EEZ. The requirements do not apply within Canadian 
territorial waters. DFO may prescribe mitigation measures that would 
apply to L-DEO's survey operations within the Canadian EEZ and Canadian 
territorial waters but NMFS is currently unaware of the specifics of 
any potential measures. While operating within the Canadian EEZ but 
outside Canadian territorial waters, if mitigation requirements 
prescribed by NMFS differ from the requirements established under 
Canadian law, L-DEO would adhere to the most protective measure. For 
operations in Canadian territorial waters, L-DEO would implement 
measures required under Canadian law (if any).

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 
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); and
     Mitigation and monitoring effectiveness.

Vessel-Based Visual Monitoring

    As described above, PSO observations will take place during daytime 
airgun operations. During seismic operations, at least five visual PSOs 
will be based aboard the Langseth. Two visual PSOs will 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 (visual or acoustic), 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);
     PSOs shall have successfully completed an approved PSO 
training course appropriate for their designated task (visual or 
acoustic). Acoustic PSOs are required to complete specialized training 
for operating PAM systems and are encouraged to have familiarity with 
the vessel with which they will be working;
     PSOs can act as acoustic or visual observers (but not at 
the same time) as long as they demonstrate that their training and 
experience are sufficient to perform the task at hand;
     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

[[Page 37304]]

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.
    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-start 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.
    If a marine mammal is detected while using the PAM system, the 
following information should be recorded:
     An acoustic encounter identification number, and whether 
the detection was linked with a visual sighting;
     Date and time when first and last heard;
     Types and nature of sounds heard (e.g., clicks, whistles, 
creaks, burst pulses, continuous, sporadic, strength of signal); and
     Any additional information recorded such as water depth of 
the hydrophone array, bearing of the animal to the vessel (if 
determinable), species or taxonomic group (if determinable), 
spectrogram screenshot, and any other notable information.

Reporting

    A report will be submitted to NMFS within 90 days after the end of 
the cruise. The report will summarize the dates and locations of 
seismic operations, and all marine mammal sightings (dates, times, 
locations, activities, associated seismic survey activities), and 
provide full documentation of methods, results, and interpretation 
pertaining to all monitoring.
    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.

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 L-DEO 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);

[[Page 37305]]

     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, L-
DEO 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).

Actions To Minimize Additional Harm to Live-Stranded (or Milling) 
Marine Mammals

    In the event of a live stranding (or near-shore atypical milling) 
event within 50 km of the survey operations, where the NMFS stranding 
network is engaged in herding or other interventions to return animals 
to the water, the Director of OPR, NMFS (or designee) will advise L-DEO 
of the need to implement shutdown for all active acoustic sources 
operating within 50 km of the stranding. Procedures related to 
shutdowns for live stranding or milling marine mammals include the 
following:
     If at any time, the marine mammal(s) die or are 
euthanized, or if herding/intervention efforts are stopped, the 
Director of OPR, NMFS (or designee) will advise L-DEO that the shutdown 
around the animals' location is no longer needed.
     Otherwise, shutdown procedures will remain in effect until 
the Director of OPR, NMFS (or designee) determines and advises L-DEO 
that all live animals involved have left the area (either of their own 
volition or following an intervention).
     If further observations of the marine mammals indicate the 
potential for re-stranding, additional coordination with L-DEO will be 
required to determine what measures are necessary to minimize that 
likelihood (e.g., extending the shutdown or moving operations farther 
away) and to implement those measures as appropriate.
    Additional Information Requests--If NMFS determines that the 
circumstances of any marine mammal stranding found in the vicinity of 
the activity suggest investigation of the association with survey 
activities is warranted, and an investigation into the stranding is 
being pursued, NMFS will submit a written request to L-DEO indicating 
that the following initial available information must be provided as 
soon as possible, but no later than 7 business days after the request 
for information:
     Status of all sound source use in the 48 hours preceding 
the estimated time of stranding and within 50 km of the discovery/
notification of the stranding by NMFS; and
     If available, description of the behavior of any marine 
mammal(s) observed preceding (i.e., within 48 hours and 50 km) and 
immediately after the discovery of the stranding.
    In the event that the investigation is still inconclusive, the 
investigation of the association of the survey activities is still 
warranted, and the investigation is still being pursued, NMFS may 
provide additional information requests, in writing, regarding the 
nature and location of survey operations prior to the time period 
above.

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.
    As described above, we authorize only the takes estimated to occur 
outside of Canadian territorial waters (Table 6); however, for the 
purposes of our negligible impact analysis and determination, we 
consider the total number of takes that are anticipated to occur as a 
result of the entire survey (including the portion of the survey that 
would occur within the Canadian territorial waters (approximately 13 
percent of the survey) (Table 7).

[[Page 37306]]



                                           Table 7--Total Estimated Take Including Canadian Territorial Waters
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                              Level B         Level A
                                                            harassment      harassment        Level B         Level A
                                                            (excluding      (excluding      harassment      harassment     Total Level B   Total Level A
                         Species                             Canadian        Canadian        (Canadian       (Canadian      harassment      harassment
                                                            territorial     territorial     territorial     territorial
                                                              waters)         waters)         waters)         waters)
--------------------------------------------------------------------------------------------------------------------------------------------------------
North Pacific right whale...............................               2               0               0               0               2               0
Gray whale, WNP.........................................               2               0               1               0               3               0
Gray whale, ENP.........................................           1,448              45             666              16           2,114              61
Humpback whale..........................................             403              14             165               4             568              18
Blue whale..............................................              31               1               4               0              35               1
Fin whale...............................................             873              44              69               1             942              45
Sei whale...............................................              34               1               7               0              41               1
Minke whale.............................................              57               2              14               0              71               2
Sperm whale.............................................             131               0              22               0             153               0
Baird's beaked whale....................................              29               0               2               0              31               0
Stejneger's beaked whale................................             120               0               9               0             129               0
Cuvier's beaked whale...................................             114               0               9               0             123               0
Pacific white-sided dolphin.............................           1,374               0             191               0           1,565               0
Northern right whale dolphin............................             927               0             451               0           1,378               0
Risso's dolphin.........................................              22               0              22               0              44               0
Killer whale............................................             290               0              89               0             379               0
Dall's porpoise.........................................           5,661             178           1,825              36           7,486             214
Harbor porpoise.........................................             990              26             455               9           1,445              35
Northern fur seal.......................................           5,812               0           1,213               0           7,025               0
California sea lion.....................................           1,258               0             433               0           1,691               0
Steller sea lion, wDPS..................................              54               0              46               0             100               0
Steller sea lion, eDPS..................................           2,381               0           2,232               0           4,613               0
Northern elephant seal..................................           6,850               0           1,429               0           8,279               0
Harbor seal.............................................           6,012               0           6,228               0          12,240               0
--------------------------------------------------------------------------------------------------------------------------------------------------------

    NMFS does not anticipate that serious injury or mortality would 
occur as a result of L-DEO's planned survey, even in the absence of 
mitigation, and none is authorized. Similarly, non-auditory physical 
effects, stranding, and vessel strike are not expected to occur.
    We are authorizing a limited number of instances of Level A 
harassment of seven species (low- and high-frequency cetacean hearing 
groups only) and Level B harassment only of the remaining marine mammal 
species. However, we believe that any PTS incurred in marine mammals as 
a result of the planned activity would be in the form of only a small 
degree of PTS, not total deafness, because of the constant movement of 
both the R/V Langseth and of the marine mammals in the project areas, 
as well as the fact that the vessel is not expected to remain in any 
one area in which individual marine mammals would be expected to 
concentrate for an extended period of time. Since the duration of 
exposure to loud sounds will be relatively short it would be unlikely 
to affect the fitness of any individuals. Also, as described above, we 
expect that marine mammals would likely move away from a sound source 
that represents an aversive stimulus, especially at levels that would 
be expected to result in PTS, given sufficient notice of the R/V 
Langseth's approach due to the vessel's relatively low speed when 
conducting seismic surveys. We expect that the majority of takes will 
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).
    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 areas; 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 (27 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.
    The tracklines of this survey either traverse or are proximal to 
critical habitat for the Mexico DPS of humpback whales and for Steller 
sea lions, and to feeding BIAs for humpback whales in general 
(including both the Hawaii and Mexico DPSs/Central North Pacific stock 
whales that are anticipated to occur in the survey area). As described 
previously, the survey area is near a feeding BIA for gray whales and 
covers the gray whale migratory BIA. However, these BIAs would not be 
affected as they are spatially and temporally separated, respectively, 
from the survey.
    Yazvenko et al. (2007) reported no apparent changes in the 
frequency of feeding activity in Western gray whales exposed to airgun 
sounds in their feeding grounds near Sakhalin Island. Goldbogen et al. 
(2013) found blue whales feeding on highly concentrated prey in shallow 
depths (such as the conditions expected within humpback feeding BIAs) 
were less likely to respond and cease foraging than whales feeding on 
deep, dispersed prey when exposed to simulated sonar sources, 
suggesting that the benefits of feeding for humpbacks foraging on high-
density prey may outweigh perceived harm from the acoustic stimulus, 
such as the seismic survey (Southall et al., 2016). Additionally, L-DEO 
will shut down the airgun array upon observation of an aggregation of 
six or more large whales, which would reduce impacts to cooperatively 
foraging animals. For all habitats, no physical impacts to habitat are 
anticipated from seismic activities. While SPLs of sufficient strength 
have

[[Page 37307]]

been known to cause injury to fish and fish and invertebrate mortality, 
in feeding habitats, the most likely impact to prey species from survey 
activities would be temporary avoidance of the affected area and any 
injury or mortality of prey species would be localized around the 
survey and not of a degree that would adversely impact marine mammal 
foraging. The duration of fish avoidance of a given area after survey 
effort stops is unknown, but a rapid return to normal recruitment, 
distribution and behavior is expected. Given the short operational 
seismic time near or traversing important habitat areas, as well as the 
ability of cetaceans and prey species to move away from acoustic 
sources, NMFS expects that there would be, at worst, minimal impacts to 
animals and habitat within these areas.
    Critical habitat for Steller sea lions has been established at 
three rookeries in southeast Alaska (Hazy Island, White Sisters Island, 
and Forrester Island near Dixon Entrance), at several major haul-outs, 
and including aquatic zones that extend 0.9 km seaward and air zones 
extending 0.9 km above the rookeries. Steller sea lions occupy 
rookeries and pup from late-May through early-July (NMFS. 2008), 
indicating that L-DEO's survey is unlikely to impact important sea lion 
behaviors in critical habitat. Impacts to Steller sea lions within 
these areas, and throughout the survey area, as well as impacts to 
other pinniped species, are expected to be limited to short-term 
behavioral disturbance, with no lasting biological consequences.

Negligible Impact Conclusions

    The survey would be of short duration (27 days of seismic 
operations), and the acoustic ``footprint'' of the survey would be 
small relative to the ranges of the marine mammals that would 
potentially be affected. Sound levels would increase in the marine 
environment in a relatively small area surrounding the vessel compared 
to the range of the marine mammals within the survey area. Short term 
exposures to survey operations are not likely to significantly disrupt 
marine mammal behavior, and the potential for longer-term avoidance of 
important areas is limited.
    The 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 and acoustic observers, and by 
minimizing the severity of any potential exposures via shutdowns of the 
airgun array. Based on previous monitoring reports for substantially 
similar activities associated with NMFS-issued IHAs, we expect that the 
mitigation will be effective in preventing, at least to some extent, 
potential PTS in marine mammals that may otherwise occur in the absence 
of the mitigation (although all authorized PTS has been accounted for 
in this analysis).
    NMFS concludes that exposures to marine mammal species and stocks 
due to L-DEO's 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 authorized take 
to impact annual rates of recruitment or survival.
    In summary and as described above, the following factors primarily 
support our determination that the impacts resulting from this activity 
are not expected to adversely affect the species or stock through 
effects on annual rates of recruitment or survival:
     No serious injury or mortality is anticipated or 
authorized;
     The activity is temporary and of relatively short duration 
(27 days);
     The anticipated impacts of the activity on marine mammals 
would primarily be temporary behavioral changes due to avoidance of the 
area around the survey vessel;
     The number of instances of potential PTS that may occur 
are expected to be very small in number. Instances of potential PTS 
that are incurred in marine mammals are expected to be of a low level, 
due to constant movement of the vessel and of the marine mammals in the 
area, and the nature of the survey design (not concentrated in areas of 
high marine mammal concentration);
     The availability of alternate areas of similar habitat 
value for marine mammals to temporarily vacate the survey area during 
the 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 survey 
would be temporary and spatially limited, and impacts to marine mammal 
foraging would be minimal; and
     The required mitigation measures, including visual and 
acoustic monitoring and shutdowns 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 required mitigation and 
monitoring measures, NMFS finds that the total marine mammal take from 
the 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 an authorization 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. 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 the estimated instances of take 
appear high when compared to the stock abundance (Table 6), or for 
which there is no currently accepted stock abundance estimate. These 
include the fin whale, minke whale, sperm whale, three species of 
beaked whale, four stocks of killer whales, harbor porpoise, and one 
stock of harbor seal. However, when other qualitative factors are used 
to inform an assessment of the likely number of individual marine 
mammals taken, the resulting numbers are appropriately considered 
small. We discuss these in further detail below.
    For all other stocks (aside from those referenced above and 
discussed below), the proposed take is less than one-third of the best 
available stock abundance (recognizing that some of those takes may be 
repeats of the same individual, thus rendering the actual percentage 
even lower), and noting that we generally excluded consideration of 
abundance information for British Columbia in considering the amount of 
take relative to the best available stock abundance information.
    The stock abundance estimates for the fin, minke, beaked, and sperm 
whale stocks that occur in the survey area are unknown, according to 
the latest SARs. The same is true for the harbor porpoise. Therefore, 
we reviewed other scientific information in making our small numbers 
determinations for these species. As noted previously, partial

[[Page 37308]]

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 59 is of small numbers. 
The same surveys produced partial abundance estimates of 1,652 and 
1,061 fin whales, for the same areas, respectively. Considering these 
two partial abundance estimates in conjunction with the British 
Columbia abundance estimate of 329 whales produces a total partial 
estimate of 3,042 whales for shelf and nearshore waters between the 
Kenai Peninsula and Amchitka Pass, the eastern Bering Sea shelf, and 
British Columbia. Given that the Northeast Pacific stock of fin whale's 
range is described as covering the entire GOA and Bering Sea, we 
reasonably assume that a total abundance estimate for the stock would 
show that the take number proposed for authorization (917) is small. In 
addition, for these stocks as well as for other stocks discussed below 
whose range spans the GOA, given that the estimated take will take 
place in a relatively small portion of the stock's range, it is likely 
there would be repeat takes of a smaller number of individuals, and 
therefore, the number of individual animals taken will be lower.
    As noted previously, Kato and Miyashita (1998) produced an 
abundance estimate of 102,112 sperm whales in the western North 
Pacific. However, this estimate is believed to be positively biased. We 
therefore refer to Barlow and Taylor (2005)'s estimate of 26,300 sperm 
whales in the northeast temperate Pacific to demonstrate that the take 
number of 136 is a small number. There is no abundance information 
available for any Alaskan stock of beaked whale. However, the take 
numbers are sufficiently small (ranging from 29-120) that we can safely 
assume that they are small relative to any reasonable assumption of 
likely population abundance for these stocks. As an example, we review 
available abundance information for other stocks of Cuvier's beaked 
whales, which is widely distributed throughout deep waters of all 
oceans and is typically the most commonly encountered beaked whale in 
its range. Where some degree of bias correction, which is critical to 
an accurate abundance estimate for cryptic species like beaked whales, 
is incorporated to the estimate, we see typical estimates in the 
thousands of animals, demonstrating that the authorized take numbers 
are reasonably considered small. Current abundance estimates include 
the Western North Atlantic stock (5,744 animals; CV = 0.36), the Hawaii 
Pelagic stock (4,431 animals, CV = 0.41), and the California/Oregon/
Washington stock (3,274 animals; CV = 0.67).
    For the southeast Alaska stock of harbor porpoise, whose range is 
defined as from Dixon Entrance to Cape Suckling (including inland 
waters), the SAR describes a partial abundance estimate, covering 
inland waters but not coastal waters, totaling 1,354 porpoise. This 
most recent abundance estimate is based on survey effort in inland 
waters during 2010-12 (Dahlheim et al., 2015). An older abundance 
estimate, based on survey effort conducted in 1997, covering both 
coastal and inland waters of the stock's range, provides a more 
complete abundance estimate of 11,146 animals (Hobbs and Waite, 2010). 
This estimate is sufficient to demonstrate that the take number (1,016) 
is small.
    For the potentially affected stocks of killer whale, it would be 
unreasonable to assume that all takes would accrue to any one stock. 
Although the Gulf of Alaska, Aleutian Islands, and Bering Sea (GOA/
BSAI) transient stock could occur in southeast Alaska, it is unlikely 
that any significant proportion of encountered whales would belong to 
this stock, which is generally considered to occur mainly from Prince 
William Sound through the Aleutian Islands and Bering Sea. Transient 
killer whales in Canadian waters are considered part of the West Coast 
transient stock, further minimizing the potential for encounter with 
the GOA/BSAI transient stock. We assume that only nominal, if any, take 
would actually accrue to this stock. Similarly, the offshore stock is 
encountered only rarely compared with resident and transient stocks. 
Seasonal sighting data collected in southeast Alaska waters between 
1991 and 2007 shows a ratio of offshore and resident killer whale 
sightings of 0.05 (Dahlheim et al., 2009), and it is unlikely that any 
amount of take accruing to this stock would exceed small numbers. We 
anticipate that most killer whales encountered would be transient or 
resident whales. For the remaining stocks, we assume that take would 
accrue to each stock in a manner roughly approximate to the stocks' 
relative abundances, i.e., 78 percent Alaska resident, 12 percent West 
Coast transient, and 10 percent northern resident. This would equate to 
approximately 226 takes from the Alaska resident stock (9.6 percent of 
the stock abundance); 35 takes from the West Coast transient stock (10 
percent of the stock abundance), and 29 takes from the northern 
resident stock (9.6 percent of the stock abundance). Based on the 
assumptions described in this paragraph, we find that the authorized 
taking is of no greater than small numbers for any stock of killer 
whale.
    If all authorized takes are allotted to each individual harbor seal 
stock, the estimated instances of take would be greater than one-third 
of the best available abundance estimate for the Sitka/Chatham Strait 
stock of harbor seal. However, similar to the discussion provided above 
for killer whale, it would be unreasonable to assume that all takes 
would accrue to any one stock. Based on the location of the survey 
relative to the potentially affected stocks' ranges, it is unlikely 
that a significant proportion of the estimated takes would occur to the 
Sitka/Chatham Strait stock (whose range just overlaps with the northern 
extent of the survey area) (Muto et al., 2020). A majority of takes are 
likely to accrue to the Dixon/Cape Decision stock, which most directly 
overlaps with the survey area. In the unlikely event that all takes 
occurred to the Dixon/Cape Decision stock, the amount of take would be 
of small numbers.
    Based on the analysis contained herein of the planned activity 
(including the required mitigation and monitoring measures) and the 
anticipated take of marine mammals, NMFS 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

    Marine mammals are legally hunted in Alaskan waters by coastal 
Alaska Natives. In the GOA, the only marine mammals under NMFS' 
jurisdiction that are currently hunted are Steller sea lions and harbor 
seals. These species are an important subsistence resource for Alaska 
Natives from southeast Alaska to the Aleutian Islands. There are 
numerous communities along the shores of the GOA that participate in 
subsistence hunting, including Juneau, Ketchikan, Sitka, and Yakutat in 
southeast Alaska (Wolfe et al., 2013). According to Muto et al. (2019), 
the annual subsistence take of Steller sea lions from the eastern stock 
was 11, and 415 northern fur seals are taken annually. In addition, 340 
harbor seals are taken annually (Muto et al. 2019). The seal harvest 
throughout Southeast Alaska is generally highest during spring and 
fall, but can occur any time of the year (Wolfe et al., 2013).
    Given the temporary nature of the activities and the fact that most

[[Page 37309]]

operations would occur further from shore, the survey would not be 
expected to have any impact on the availability of the species or 
stocks for subsistence users. L-DEO conducted outreach to local 
stakeholders, including subsistence communities, to notify subsistence 
hunters of the planned survey, to identify the measures that would be 
taken to minimize any effects on the availability of marine mammals for 
subsistence uses, and to provide an opportunity for comment on these 
measures. During operations, radio communications and Notice to 
Mariners would keep interested parties apprised of vessel activities. 
NMFS is unaware of any other subsistence uses of the affected marine 
mammal stocks or species that could be implicated by this action. On 
this basis, NMFS preliminarily determined that the total taking of 
affected species or stocks would not have an unmitigable adverse impact 
on the availability of such species or stocks for taking for 
subsistence purposes, and requested comments or any information that 
may help to inform this determination. We did not receive any comments 
or additional information regarding potential impacts on the 
availability of marine mammals for subsistence uses. Therefore, NMFS 
has determined that the total taking of affected species or stocks 
would not have an unmitigable adverse impact on the availability of 
such species or stocks for taking for subsistence purposes.

National Environmental Policy Act

    In compliance with the National Environmental Policy Act of 1969 
(42 U.S.C. 4321 et seq.), as implemented by the regulations published 
by the Council on Environmental Quality (40 CFR parts 1500-1508), the 
National Science Foundation prepared an Environmental Analysis (EA) to 
consider the direct, indirect, and cumulative effects to the human 
environment from this geophysical survey of the Queen Charlotte Fault. 
NSF's EA was made available to the public for review and comment in 
relation to its suitability for adoption by NMFS in order to assess the 
impacts to the human environment of issuance of an IHA to L-DEO. In 
compliance with NEPA and the CEQ regulations, as well as NOAA 
Administrative Order 216-6A, NMFS has reviewed the NSF's EA, determined 
it to be sufficient, and adopted that EA and signed a Finding of No 
Significant Impact (FONSI). NSF's EA is available at www.nsf.gov/geo/oce/envcomp/, and NMFS' FONSI is available at www.fisheries.noaa.gov/action/incidental-take-authorization-lamont-doherty-earth-observatory-geophysical-survey-queen.

Endangered Species Act (ESA)

    Section 7(a)(2) of the Endangered Species Act of 1973 (ESA: 16 
U.S.C. 1531 et seq.) requires that each Federal agency insure that any 
action it authorizes, funds, or carries out is not likely to jeopardize 
the continued existence of any endangered or threatened species or 
result in the destruction or adverse modification of designated 
critical habitat. To ensure ESA compliance for the issuance of IHAs, 
NMFS consults internally whenever we propose to authorize take for 
endangered or threatened species.
    On July 7, 2021, the NMFS Office of Protected Resources (OPR) ESA 
Interagency Cooperation Division issued a Biological Opinion under 
section 7 of the ESA, on the issuance of an IHA to L-DEO under section 
101(a)(5)(D) of the MMPA by the NMFS OPR Permits and Conservation 
Division. The Biological Opinion concluded that the proposed action is 
not likely to jeopardize the continued existence of the sei whale, fin 
whale, blue whale, sperm whale, Mexico DPS of humpback whale, western 
North Pacific DPS of gray whale, North Pacific right whale, and western 
DPS of Steller sea lion.

Authorization

    As a result of these determinations, NMFS has issued an IHA to L-
DEO for conducting a marine geophysical survey of the Queen Charlotte 
Fault beginning in July 2021, provided the previously mentioned 
mitigation, monitoring, and reporting requirements are incorporated.

    Dated: July 12, 2021.
Catherine Marzin,
Acting Director, Office of Protected Resources, National Marine 
Fisheries Service.
[FR Doc. 2021-15046 Filed 7-14-21; 8:45 am]
BILLING CODE 3510-22-P