Takes of Marine Mammals Incidental to Specified Activities; Taking Marine Mammals Incidental to Marine Geophysical Surveys in the Northeast Pacific Ocean, 35073-35099 [2019-15516]

Agencies

• DEPARTMENT OF COMMERCE
• National Oceanic and Atmospheric Administration

[Federal Register Volume 84, Number 140 (Monday, July 22, 2019)]
[Notices]
[Pages 35073-35099]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2019-15516]


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DEPARTMENT OF COMMERCE

National Oceanic and Atmospheric Administration

RIN 0648-XG948


Takes of Marine Mammals Incidental to Specified Activities; 
Taking Marine Mammals Incidental to Marine Geophysical Surveys in the 
Northeast Pacific Ocean

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

ACTION: Notice; issuance of an 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 
Lamont-Doherty Earth Observatory (L-DEO) to incidentally harass, by 
Level A and Level B harassment, marine mammals during seismic 
activities associated with a marine geophysical survey in the Northeast 
Pacific Ocean.

DATES: This Authorization is effective from July 10, 2019 through July 
9, 2020.

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

SUPPLEMENTARY INFORMATION:

[[Page 35074]]

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 such 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 such takings are set forth.

Summary of Request

    On December 21, 2018, NMFS received a request from L-DEO for an IHA 
to take marine mammals incidental to a marine geophysical survey of the 
Axial Seamount in the Northeast Pacific Ocean. The application was 
deemed adequate and complete on May 3, 2019. L-DEO's request is for 
take of a small number of 26 species of marine mammals by Level B 
harassment and Level A harassment. Neither L-DEO nor NMFS expects 
serious injury or mortality to result from this activity and, 
therefore, an IHA is appropriate.

Description of Specified Activity

    Researchers from the University of Texas at Austin, University of 
Nevada Reno, University of California San Diego, with funding from the 
U.S. National Science Foundation (NSF), plan to conduct high-energy 
seismic surveys from Research Vessel (R/V) Marcus G. Langseth 
(Langseth) in the Northeast Pacific Ocean during summer 2019. The NSF-
owned Langseth is operated by Columbia University's L-DEO under an 
existing Cooperative Agreement. The planned two-dimensional (2-D) and 
three-dimensional (3-D) seismic surveys would occur in International 
Waters outside of the U.S. Exclusive Economic Zone (EEZ). The 2-D 
survey would use a 36-airgun towed array with a total discharge volume 
of ~6,600 cubic inches (in\3\); the 3-D survey would employ an 18-
airgun array with a discharge volume of ~3,300 in\3\. The total survey 
duration would be approximately 35 days. A total of ~3,760 kilometers 
(km) of transect lines would be surveyed in the Northeast Pacific 
Ocean: ~3,196 km during the 3-D survey and 564 km during the 2-D 
survey.
    A detailed description of the planned geophysical survey is 
provided in the Federal Register notice for the proposed IHA (84 FR 
26940; June 10, 2019). Since that time, no changes have been made to 
the planned survey activities. Therefore, a detailed description is not 
provided here. Please refer to that Federal Register notice for the 
description of the specific activity.

Comments and Responses

    A notice of NMFS's proposal to issue an IHA to L-DEO was published 
in the Federal Register on June 10, 2019 (84 FR 26940). That notice 
described, in detail, L-DEO's activity, the marine mammal species that 
may be affected by the activity, and the anticipated effects on marine 
mammals. During the 30-day public comment period, NMFS received 
comments from the Marine Mammal Commission (Commission).
    Comment: The Commission recommended that NMFS require L-DEO to re-
estimate the proposed Level A and Level B harassment zones and 
associated takes of marine mammals using (1) both operational 
(including number/type/spacing of airguns, tow depth, source level/
operating pressure, operational volume) and site-specific environmental 
(including sound speed profiles, bathymetry, and sediment 
characteristics at a minimum) parameters, (2) a comprehensive source 
model (i.e., Gundalf Optimizer or AASM) and (3) an appropriate sound 
propagation model for the proposed incidental harassment authorization. 
Specifically, the Commission reiterates that L-DEO should be using the 
ray-tracing propagation model BELLHOP--which is a free, standard 
propagation code that readily incorporates all environmental inputs 
listed herein, rather than the limited, in-house MATLAB code currently 
in use.
    Response: NMFS acknowledges the Commission's concerns about L-DEO's 
current modeling approach for estimating Level A and Level B harassment 
zones and takes. L-DEO's application and the Federal Register notice of 
the proposed IHA (84 FR 26940; June 10, 2019) describe the applicant's 
approach to modeling Level A and Level B harassment zones. The model L-
DEO currently uses does not allow for the consideration of 
environmental and site-specific parameters as requested by the 
Commission.
    L-DEO's application describes their approach to modeling Level A 
and Level B harassment zones. In summary, L-DEO acquired field 
measurements for several array configurations at shallow, intermediate, 
and deep-water depths during acoustic verification studies conducted in 
the northern Gulf of Mexico in 2007 and 2008 (Tolstoy et al., 2009). 
Based on the empirical data from those studies, L-DEO developed a sound 
propagation modeling approach that predicts received sound levels as a 
function of distance from a particular airgun array configuration in 
deep water. For this survey, L-DEO modeled Level A and Level B 
harassment zones based on the empirically-derived measurements from the 
Gulf of Mexico calibration survey (Appendix H of NSF-USGS 2011). L-DEO 
used the deep-water radii obtained from model results down to a maximum 
water depth of 2,000 meters (m) (Figures 2 and 3 in Appendix H of NSF-
USGS 2011).
    In 2015, LDEO explored the question of whether the Gulf of Mexico 
calibration data described above adequately informs the model to 
predict exclusion isopleths in other areas by conducting a 
retrospective sound power analysis of one of the lines acquired during 
L-DEO's seismic survey offshore New Jersey in 2014 (Crone, 2015). NMFS 
presented a comparison of the predicted radii (i.e., modeled exclusion 
zones) with radii based on in situ measurements (i.e., the upper bound 
[95th percentile] of the cross-line prediction) in a previous notice of 
issued Authorization for LDEO (see 80 FR 27635, May 14, 2015, Table 1). 
Briefly, the analysis presented in Crone (2015), specific to the survey 
site offshore New Jersey, confirmed that in-situ, site specific 
measurements and estimates of 160 decibel (dB) and 180 dB isopleths 
collected by the hydrophone streamer of the R/V Langseth in shallow 
water were smaller than the modeled (i.e., predicted) zones for two 
seismic surveys conducted offshore New Jersey in shallow water in 2014 
and 2015. In that particular case, Crone's (2015) results showed that 
L-DEO's modeled 180 decibel (dB) and

[[Page 35075]]

160 dB zones were approximately 28 percent and 33 percent larger, 
respectively, than the in-situ, site-specific measurements, thus 
confirming that L-DEO's model was conservative in that case.
    The following is a summary of two additional analyses of in-situ 
data that support L-DEO's use of the modeled Level A and Level B 
harassment zones in this particular case. In 2010, L-DEO assessed the 
accuracy of their modeling approach by comparing the sound levels of 
the field measurements acquired in the Gulf of Mexico study to their 
model predictions (Diebold et al., 2010). They reported that the 
observed sound levels from the field measurements fell almost entirely 
below the predicted mitigation radii curve for deep water (i.e., 
greater than 1,000 m; 3,280.8 ft) (Diebold et al., 2010). In 2012, L-
DEO used a similar process to model distances to isopleths 
corresponding to Level A and Level B harassment thresholds for a 
shallow-water seismic survey in the northeast Pacific Ocean offshore 
Washington State. LDEO conducted the shallow-water survey using a 6,600 
in\3\ airgun configuration aboard the R/V Langseth and recorded the 
received sound levels on both the shelf and slope using the Langseth's 
8 km hydrophone streamer. Crone et al. (2014) analyzed those received 
sound levels from the 2012 survey and confirmed that in-situ, site 
specific measurements and estimates of the 160 dB and 180 dB isopleths 
collected by the Langseth's hydrophone streamer in shallow water were 
two to three times smaller than L-DEO's modeling approach had 
predicted. While the results confirmed the role of bathymetry in sound 
propagation, Crone et al. (2014) were also able to confirm that the 
empirical measurements from the Gulf of Mexico calibration survey (the 
same measurements used to inform L-DEO's modeling approach for the 
planned surveys in the northwest Atlantic Ocean) overestimated the size 
of the exclusion and buffer zones for the shallow-water 2012 survey off 
Washington State and were thus precautionary, in that particular case.
    NMFS continues to work with L-DEO to address the issue of 
incorporating site-specific information for future authorizations for 
seismic surveys. However, L-DEO's current modeling approach (supported 
by the three data points discussed previously) represents the best 
available information for NMFS to reach determinations for this IHA. As 
described earlier, the comparisons of L-DEO's model results and the 
field data collected at multiple locations (i.e., the Gulf of Mexico, 
offshore Washington State, and offshore New Jersey) illustrate a degree 
of conservativeness built into L-DEO's model for deep water, which NMFS 
expects to offset some of the limitations of the model to capture the 
variability resulting from site-specific factors. Based upon the best 
available information (i.e., the three data points, two of which are 
peer-reviewed, discussed in this response), NMFS finds that the Level A 
and Level B harassment zone calculations are appropriate for use in 
this particular IHA.
    The use of models for calculating Level A and Level B harassment 
zones and for developing take estimates is not a requirement of the 
MMPA incidental take authorization process. Further, NMFS does not 
prescribe specific model parameters nor a specific model for applicants 
as part of the MMPA incidental take authorization process at this time, 
although we do review methods to ensure they adequately predict take. 
There is a level of variability not only with parameters in the models, 
but also the uncertainty associated with data used in models, and 
therefore, the quality of the model results submitted by applicants. 
NMFS considers this variability when evaluating applications and the 
take estimates and mitigation measures that the model informs. NMFS 
takes into consideration the model used, and its results, in 
determining the potential impacts to marine mammals; however, it is 
just one component of the analysis during the MMPA authorization 
process as NMFS also takes into consideration other factors associated 
with the activity (e.g., geographic location, duration of activities, 
context, sound source intensity, etc.).
    Comment: Given the shortcomings noted for L-DEO's source and sound 
propagation modeling and the requirements that other action proponents 
are obliged to fulfill, the Commission recommended that NMFS require L-
DEO to archive, analyze, and compare the in-situ data collected by the 
hydrophone streamer and ocean bottom seismometers (OBSs) to L-DEO's 
modeling results for the extents of the Level A and B harassment zones 
based on the various water depths to be surveyed and provide the data 
and results to NMFS.
    Response: Based on information presented by the applicant and 
supported by published analysis such as Diebold et al. 2010, Tolstoy et 
al. 2009, Crone et al. 2014, Crone et al. 2017, Barton et al. 2006, and 
Diebold et al. 2006, L-DEO modeling results and predicted distances to 
harassment zones are likely more conservative than actual distances 
measured from data collected in situ for depths from shallow to deep. 
The Commission stated one reason for recommending that NMFS require L-
DEO to conduct sound source verification efforts was due to the short-
comings of the L-DEO model. However, as previously noted, the L-DEO 
model is conservative and is viewed appropriate for R/V Langseth 
operations. Use of the L-DEO model is further supported by ten years of 
successful operations with no observed harm to marine life. For these 
reasons, additional sound source verification efforts are not warranted 
at this time.
    Comment: The Commission recommended that NMFS recalculate the 
densities (and thus, estimated take) of Guadalupe fur seals, northern 
fur seals, and northern elephant seals to include more recent data and 
population growth through 2019 rather than 2017.
    Response: Through discussions with the Commission, NMFS has 
recalculated the densities of these species. The density of Guadalupe 
fur seals increased to 0.00343 animals per square kilometer (km\2\), 
the density of northern fur seals increased to 0.01065 animals per 
km\2\, and the density of northern elephant seals increased to 0.03333 
animals per km\2\. Estimated take of these three species increased 
accordingly. Further detail regarding these changes is included in the 
Estimated Take section later in this document.
    Comment: The Commission recommended that NMFS use a consistent 
approach for requiring all geophysical and seismic survey operators to 
abide by the same general mitigation measures, including prohibiting L-
DEO from using power downs and the mitigation airgun during its 
geophysical surveys.
    Response: NMFS is in the process of developing protocols that could 
be applied to geophysical and seismic surveys. The protocols are being 
developed on the basis of detailed review of available literature, 
including peer-reviewed science, review articles, gray literature, and 
protocols required by other countries around the world. NMFS will share 
the protocols with the Commission when they are ready for external 
comment and review.
    Note that power downs to the single 40 in\3\ airgun are only 
allowed/required in lieu of shutdown when certain species of dolphins, 
specifically identified in the Mitigation section below, enter the 
shutdown zone. In all other cases, shutdown would be implemented under 
conditions as described in the IHA.
    Comment: The Commission noted that monitoring and reporting 
requirements adopted need to be

[[Page 35076]]

sufficient to provide a reasonably accurate assessment of the manner of 
taking and the numbers of animals taken incidental to the specified 
activity. Those assessments should account for all animals in the 
various survey areas, including those animals directly on the trackline 
that are not detected and how well animals are detected based on the 
distance from the observer which is achieved by incorporating g(0) and 
f(0) values. The Commission recommended that NMFS require L-DEO to use 
the Commission's method as described in the Commission's Addendum to 
better estimate the numbers of marine mammals taken by Level A and B 
harassment for the incidental harassment authorization. The Commission 
stated that all other NSF-affiliated entities and all seismic operators 
should use this method as well.
    Response: NMFS agrees that reporting of the manner of taking and 
the numbers of animals incidentally taken should account for all 
animals taken, including those animals that are not detected and how 
well animals are detected based on the distance from the observer, to 
the extent practicable. NMFS appreciates the Commission's 
recommendations and further requires that L-DEO provide an estimate of 
take, including marine mammals that were not detected in their 
reporting for this survey, as it has in previous actions. NMFS welcomes 
L-DEO's input on a method to generate this quantitative method, but in 
the absence of a new procedure, recommends that use of the Commission's 
method for marine geophysical surveys, which was attached to the 
Commission's comment letter. We look forward to engaging further with 
L-DEO, the Commission and other applicants to refine methods to 
incorporate consideration of g(0) and f(0) values into post-survey take 
estimates.
    Comment: The commission recommended that NMFS refrain from using 
the proposed renewal process for L-DEO's authorization based on the 
complexity of analysis and potential for impacts on marine mammals, and 
the potential burden on reviewers of reviewing key documents and 
developing comments quickly. Additionally, the Commission recommends 
that NMFS use the IHA renewal process sparingly and selectively for 
activities expected to have the lowest levels of impacts to marine 
mammals and that require less complex analysis.
    Response: We appreciate the Commission's input and direct the 
reader to our recent response to the identical comment, which can be 
found at 84 FR 31032 (June 28, 2019), pg. 31035-31036
    Comment: The Commission noted that the proposed surveys are 
scheduled to begin immediately after the public comment period closed 
and expressed concern that NMFS did not have adequate time to consider 
public comments before issuing the IHA. The Commission recommended NMFS 
more thoroughly review applications, draft Federal Register notices, 
and draft proposed authorizations prior to submitting any proposed 
authorizations to the Federal Register, as well as require earlier 
submission of applications and other documentation to ensure sufficient 
time to prepare the proposed authorization and consider comments 
received from the public.
    Response: NMFS thanks the Commission for its concerns regarding the 
IHA process. NMFS thoroughly reviewed the comments received and 
considered all comments in making appropriate revisions to the final 
IHA. NMFS encourages all applicants to submit applications for IHAs 
five to eight months in advance of the intended project start date and 
for rulemakings/LOAs at least nine months, and preferably 15 months, in 
advance of the intended project start date. More generally, NMFS 
publishes Federal Register notices for proposed IHAs as quickly as 
possible once the application is received and aims to allow more time 
on the back end of the comment period, but there are situations where 
the length of processing times are driven by the exigency of an 
applicant's activity start date or by the need to work with applicants 
to ensure we have the necessary information to deem an application 
adequate and complete. Here, NMFS provided the required 30-day notice 
for public comment, and has adequately considered the comments received 
in making the necessary findings for this IHA.

Description of Marine Mammals in the Area of Specified Activities

    Sections 3 and 4 of the application summarize available information 
regarding status and trends, distribution and habitat preferences, and 
behavior and life history, of the potentially affected species. 
Additional information regarding population trends and threats may be 
found in NMFS's Stock Assessment Reports (SARs; https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessments) and more general information about these species 
(e.g., physical and behavioral descriptions) may be found on NMFS's 
website (https://www.fisheries.noaa.gov/find-species).
    Table 1 lists all species 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 ESA and potential 
biological removal (PBR), where known. For taxonomy, we follow 
Committee on Taxonomy (2016). PBR is defined by the MMPA as the maximum 
number of animals, not including natural mortalities, that may be 
removed from a marine mammal stock while allowing that stock to reach 
or maintain its optimum sustainable population (as described in NMFS's 
SARs). While no mortality is anticipated or authorized here, PBR and 
annual serious injury and mortality from anthropogenic sources are 
included here as gross indicators of the status of the species and 
other threats.
    Marine mammal abundance estimates presented in this document 
represent the total number of individuals that make up a given stock or 
the total number estimated within a particular study or survey area. 
NMFS's stock abundance estimates for most species represent the total 
estimate of individuals within the geographic area, if known, that 
comprises that stock. For some species, this geographic area may extend 
beyond U.S. waters. All managed stocks in this region are assessed in 
NMFS's U.S. Pacific and Alaska SARs (Caretta et al., 2018; Muto et al., 
2018). All values presented in Table 1 are the most recent available at 
the time of publication and are available in the 2017 SARs (Caretta et 
al., 2018; Muto et al., 2018) and draft 2018 SARs (available online at: 
https://www.fisheries.noaa.gov/national/marine-mammal-protection/draft-marine-mammal-stock-assessment-reports).

[[Page 35077]]



                                               Table 1--Marine Mammals That Could Occur in the Survey Area
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                                                                                ESA/MMPA       Stock abundance
                                                                                 status;       (CV, Nmin, most
           Common name               Scientific name           Stock          strategic (Y/    recent abundance            PBR           Annual M/SI \3\
                                                                                 N) \1\          survey) \2\
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                                          Order Cetartiodactyla--Cetacea--Superfamily Mysticeti (baleen whales)
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Family Eschrichtiidae:...........
    Gray whale...................  Eschrichtius         Eastern North        -/-; N          26,960 (0.05,        801.................  138.
                                    robustus.            Pacific.                             25,849, 2016).
                                                        Western North        E/D; Y          175 (0.05, 167,      0.07................  Unknown.
                                                         Pacific.                             2016).
Family Balaenidae:
    North Pacific right whale....  Eubalaena japonica.  Eastern North        E/D; Y          31 (0.226, 26,       0.05................  0.
                                                         Pacific.                             2015).
Family Balaenopteridae
 (rorquals):
    Humpback whale...............  Megaptera            California/Oregon/   -/-; Y          1,918 (0.03, 1,876,  11..................  >9.2.
                                    novaeangliae.        Washington.                          2014).
    Minke whale..................  Balaenoptera         California/Oregon/   -/-; N          636 (0.72, 369,      3.5.................  >1.3.
                                    acutorostrata.       Washington.                          2014).
    Sei whale....................  Balaenoptera         Eastern North        E/D; Y          519 (0.4, 374,       0.75................  0.
                                    borealis.            Pacific.                             2014).
    Fin whale....................  Balaenoptera         California/Oregon/   E/D; Y          9,029 (0.12, 8,127,  81..................  >2.0.
                                    physalus.            Washington.                          2014).
    Blue whale...................  Balaenoptera         Eastern North        E/D; Y          1,647 (0.07, 1,551,  2.3.................  >0.2.
                                    musculus.            Pacific.                             2011).
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                                            Superfamily Odontoceti (toothed whales, dolphins, and porpoises)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Family Physeteridae:
    Sperm whale..................  Physeter             California/Oregon/   E/D; Y          1,967 (0.57, 1,270,  2.5.................  0.9.
                                    macrocephalus.       Washington.                          2014).
Family Kogiidae:
    Pygmy sperm whale............  Kogia breviceps....  California/Oregon/   -/-; N          4,111 (1.12, 1,924,  19..................  0.
                                                         Washington.                          2014).
    Dwarf sperm whale............  Kogia sima.........  California/Oregon/   -/-; N          Unknown (Unknown,    Undetermined........  0.
                                                         Washington.                          Unknown, 2014).
Family Ziphiidae (beaked whales):
    Cuvier's beaked whale........  Ziphius cavirostris  California/Oregon/   -/-; N          3,274 (0.67, 2,059,  21..................  <0.1.
                                                         Washington.                          2014).
    Baird's beaked whale.........  Berardius bairdii..  California/Oregon/   -/-; N          2,697 (0.6, 1,633,   16..................  0.
                                                         Washington.                          2014).
    Blainville's beaked whale....  Mesoplodon           California/Oregon/   -/-; N          3,044 (0.54, 1,967,  20..................  0.1.
                                    densirostris.        Washington.                          2014).
    Hubbs' beaked whale..........  Mesoplodon
                                    carlshubbi.
    Stejneger's beaked whale.....  Mesoplodon
                                    stejnegeri.
Family Delphinidae:
    Bottlenose dolphin...........  Tursiops truncatus.  California/Oregon/   -/-; N          1,924 (0.54, 1,255,  11..................  >1.6.
                                                         Washington                           2014).
                                                         offshore.
    Striped dolphin..............  Stenella             California/Oregon/   -/-; N          29,211 (0.2,         238.................  >0.8.
                                    coeruleoalba.        Washington.                          24,782, 2014).
    Short-beaked common dolphin..  Delphinus delphis..  California/Oregon/   -/-; N          969,861 (0.17,       8,393...............  >40.
                                                         Washington.                          839,325, 2014).
    Pacific white-sided dolphin..  Lagenorhynchus       California/Oregon/   -/-; N          26,814 (0.28,        191.................  7.5.
                                    obliquidens.         Washington.                          21,195, 2014).
    Northern right whale dolphin.  Lissodelphis         California/Oregon/   -/-; N          26,556 (0.44,        179.................  3.8.
                                    borealis.            Washington.                          18,608, 2014).
    Risso's dolphin..............  Grampus griseus....  California/Oregon/   -/-; N          6,336 (0.32, 4,817,  46..................  >3.7.
                                                         Washington.                          2014).
    False killer whale...........  Pseudorca            Hawaii Pelagic.....  -/-; N          1,540 (0.66, 928,    9.3.................  7.6.
                                    crassidens.                                               2010).
    Killer whale.................  Orcinus orca.......  Offshore...........  -/-; N          240 (0.49, 162,      1.6.................  0.
                                                                                              2014).
                                                        Southern Resident..  E/D; Y          83 (N/A, 83, 2016).  0.14................  0.
                                                        Northern Resident..  -/-; N          261 (N/A, 261,       1.96................  0.
                                                                                              2011).
                                                        West Coast           -/-; N          243 (N/A, 243,       2.4.................  0.
                                                         Transient.                           2009).
    Short-finned pilot whale.....  Globicephala         California/Oregon/   -/-; N          836 (0.79, 466,      4.5.................  1.2.
                                    macrorhynchus.       Washington.                          2014).
Family Phocoenidae (porpoises):
    Harbor porpoise..............  Phocoena phocoena..  Northern Oregon/     -/-; N          21,487 (0.44,        151.................  >3.0.
                                                         Washington Coast.                    15,123, 2011).
    Dall's porpoise..............  Phocoenoides dalli.  California/Oregon/   -/-; N          25,750 (0.45,        172.................  0.3.
                                                         Washington.                          17,954, 2014).
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                         Order Carnivora--Superfamily Pinnipedia
--------------------------------------------------------------------------------------------------------------------------------------------------------
Family Otariidae (eared seals
and sea lions):
    Northern fur seal............  Callorhinus ursinus  Eastern Pacific....  -/D; Y          620,660 (0.2,        11,295..............  457.
                                                                                              525,333, 2016).
                                                        California.........  -/D; N          14,050 (N/A, 7,524,  451.................  1.8.
                                                                                              2013).
    California sea lion..........  Zalophus             U.S................  -/-; N          257,606 (N/A,        14,011..............  >197.
                                    californianus.                                            233,515, 2014).
    Steller sea lion.............  Eumetopias jubatus.  Eastern U.S........  -/-; N          41,638 (see SAR,     2,498...............  108.
                                                                                              41,638, 2015).

[[Page 35078]]

 
    Guadalupe fur seal...........  Arctocephalus        Mexico.............  T/D; Y          20,000 (N/A,         542.................  >3.2.
                                    townsendi.                                                15,830, 2010).
Family Phocidae (earless seals):
    Harbor seal..................  Phoca vitulina.....  Oregon/Washington    -/-; N          Unknown (Unknown,    Undetermined........  10.6.
                                                         Coastal.                             Unknown, 1999).
    Northern elephant seal.......  Mirounga             California Breeding  -/-; N          179,000 (N/A,        4,882...............  8.8.
                                    angustirostris.                                           81,368, 2010).
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ Endangered Species Act (ESA) status: Endangered (E), Threatened (T)/MMPA status: Depleted (D). A dash (-) indicates that the species is not listed
  under the ESA or designated as depleted under the MMPA. Under the MMPA, a strategic stock is one for which the level of direct human-caused mortality
  exceeds PBR or which is determined to be declining and likely to be listed under the ESA within the foreseeable future. Any species or stock listed
  under the ESA is automatically designated under the MMPA as depleted and as a strategic stock.
\2\ NMFS marine mammal stock assessment reports online at: www.nmfs.noaa.gov/pr/sars/. CV is coefficient of variation; Nmin is the minimum estimate of
  stock abundance. In some cases, CV is not applicable.
\3\ These values, found in NMFS's SARs, represent annual levels of human-caused mortality plus serious injury from all sources combined (e.g.,
  commercial fisheries, ship strike). Annual M/SI often cannot be determined precisely and is in some cases presented as a minimum value or range. A CV
  associated with estimated mortality due to commercial fisheries is presented in some cases.
Note--Italicized species are not expected or authorized to be taken.

    All species that could potentially occur in the planned survey 
areas are included in Table 1. However, the temporal and/or spatial 
occurrence of gray whales, Southern Resident and Northern Resident 
killer whales, harbor porpoise, harbor seal, California sea lion, and 
Steller sea lion is such that take is not expected to occur, and they 
are not discussed further beyond the explanation provided here. These 
species are found in the eastern North Pacific, but are generally found 
in coastal waters and are not expected to occur offshore in the survey 
area.
    A detailed description of the species likely to be affected by L-
DEO's planned surveys, including brief introductions to the species and 
relevant stocks as well as available information regarding population 
trends and threats, and information regarding local occurrence, were 
provided in the Federal Register notice for the proposed IHA (84 FR 
26940; June 10, 2019). Since that time, we are not aware of any changes 
in the status of these species and stocks; therefore, detailed 
descriptions are not provided here. Please refer to that Federal 
Register notice for these descriptions. Please also refer to the NMFS 
website (https://www.fisheries.noaa.gov/find-species) for generalized 
species accounts.

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

    The pinniped functional hearing group was modified from Southall et 
al. (2007) on the basis of data indicating that phocid species have 
consistently demonstrated an extended frequency range of hearing 
compared to otariids, especially in the higher frequency range 
(Hemil[auml] et al., 2006; Kastelein et al., 2009; Reichmuth and Holt, 
2013).
    For more detail concerning these groups and associated frequency 
ranges, please see NMFS (2018) for a review of available information. 
26 marine mammal species (23 cetacean and three

[[Page 35079]]

pinniped (two otariid and one phocid) species) have the reasonable 
potential to co-occur with the planned survey activities. Please refer 
to Table 1. Of the cetacean species that may be present, five are 
classified as low-frequency cetaceans (i.e., all mysticete species), 15 
are classified as mid-frequency cetaceans (i.e., all delphinid and 
ziphiid species and the sperm whale), and three are classified as high-
frequency cetaceans (i.e., harbor porpoise and Kogia spp.).

Potential Effects of Specified Activities on Marine Mammals and Their 
Habitat

    The effects of underwater noise from seismic airguns and other 
associated activities for the Northeast Pacific geophysical surveys 
have the potential to result in behavioral harassment and a small 
degree of permanent threshold shift (PTS) in marine mammals in the 
vicinity of the action area associated direct effects on marine 
mammals. The project would not result in permanent impacts to habitats 
used directly by marine mammals, such as haulout sites, but may have 
potential short-term impacts to food sources such as forage fish or 
zooplankton during the geophysical survey. These potential effects are 
discussed in detail in the Federal Register notice for the proposed IHA 
(84 FR 26940; June 10, 2019), therefore that information is not 
repeated here. Please refer to that Federal Register notice for that 
information.
    The main impact associated with L-DEO's Northeast Pacific 
geophysical survey would be temporarily elevated sound levels and the 
associated direct effects on marine mammals. The project would not 
result in permanent impacts to habitats used directly by marine 
mammals, such as haulout sites, but may have potential short-term 
impacts to food sources such as forage fish or zooplankton during the 
geophysical survey. These potential effects are discussed in detail in 
the Federal Register notice for the proposed IHA (84 FR 26940; June 10, 
2019), therefore that information is not repeated here. Please refer to 
that Federal Register notice for that information.

Estimated Take

    This section provides an estimate of the number of incidental takes 
authorized through this IHA, which will inform both NMFS' consideration 
of ``small numbers'' and the negligible impact determination. Based on 
input received during the public comment period, minor changes were 
made to the densities of three species of marine mammals (northern fur 
seal, Guadalupe fur seal, and northern elephant seal) and the number of 
Level A takes for sei whales. Takes of these species have been adjusted 
accordingly, but these changes do not affect any of our findings.
    Harassment is the only type of take expected to result from these 
activities. Except with respect to certain activities not pertinent 
here, section 3(18) of the MMPA defines ``harassment'' as any act of 
pursuit, torment, or annoyance, which (i) has the potential to injure a 
marine mammal or marine mammal stock in the wild (Level A harassment); 
or (ii) has the potential to disturb a marine mammal or marine mammal 
stock in the wild by causing disruption of behavioral patterns, 
including, but not limited to, migration, breathing, nursing, breeding, 
feeding, or sheltering (Level B harassment).
    Authorized takes would primarily be 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., kogiidae spp.), due to larger predicted 
auditory injury zones for those functional hearing groups. The required 
mitigation and monitoring measures are expected to minimize the 
severity of such taking to the extent practicable.
    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 (up to 43.7 m). Moreover, the source level 
of the array is a theoretical definition assuming a point source and 
measurement in the far-field of the source (MacGillivray, 2006). As 
described by Caldwell and Dragoset (2000), an array is not a point 
source, but one that spans a small area. In the far-field, individual 
elements in arrays will effectively work as one source because 
individual pressure peaks will have coalesced into one relatively broad 
pulse. The array can then be considered a ``point source.'' For 
distances within the near-field, i.e., approximately 2-3 times the 
array dimensions, pressure peaks from individual elements do not arrive 
simultaneously because the observation point is not equidistant from 
each element. The effect is destructive interference of the outputs of 
each element, so that peak pressures in the near-field will be 
significantly lower than the output of the largest individual element. 
Here, the 230 dB 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 230 dB peak SPL 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.
    In order to provide quantitative support for this theoretical 
argument, we calculated expected maximum distances at which the near-
field would transition to the far-field (Table 5). For a specific array 
one can estimate the distance at which the near-field transitions to 
the far-field by:
[GRAPHIC] [TIFF OMITTED] TN22JY19.005

with the condition that D >> [lambda], and where D is the distance, L 
is the longest dimension of the array, and [lambda] is the wavelength 
of the signal (Lurton, 2002). Given that [lambda] can be defined by:
[GRAPHIC] [TIFF OMITTED] TN22JY19.006

where f is the frequency of the sound signal and v is the speed of the 
sound in the medium of interest, one can rewrite the equation for D as:
[GRAPHIC] [TIFF OMITTED] TN22JY19.007

and calculate D directly given a particular frequency and known speed 
of sound (here assumed to be 1,500 meters per second in water, although 
this varies with environmental conditions).
    To determine the closest distance to the arrays at which the source 
level predictions in Table 1 are valid (i.e., maximum extent of the 
near-field), we calculated D based on an assumed frequency of 1 kHz. A 
frequency of 1 kHz is commonly used in near-field/far-field 
calculations for airgun arrays (Zykov and Carr, 2014; MacGillivray, 
2006; NSF and USGS, 2011), and based on representative airgun spectrum 
data and field measurements of an airgun array used on the R/V Marcus 
G. Langseth, nearly all (greater than 95 percent) of the energy from 
airgun arrays is below 1 kHz (Tolstoy et al., 2009). Thus, using 1 kHz 
as the upper cut-off for calculating the maximum extent of the near-
field should reasonably represent the near-field extent in field 
conditions.
    If the largest distance to the peak sound pressure level threshold 
was equal to or less than the longest dimension of the array (i.e., 
under the array), or within the near-field, then received levels that 
meet or exceed the threshold in most cases are not expected

[[Page 35080]]

to occur. This is because within the near-field and within the 
dimensions of the array, the source levels specified in Table 1 are 
overestimated and not applicable. In fact, until one reaches a distance 
of approximately three or four times the near-field distance the 
average intensity of sound at any given distance from the array is 
still less than that based on calculations that assume a directional 
point source (Lurton, 2002). The 6,600 in\3\ airgun array used in the 
2D survey has an approximate diagonal of 28.8 m, resulting in a near-
field distance of 138.7 m at 1 kHz (NSF and USGS, 2011). Field 
measurements of this array indicate that the source behaves like 
multiple discrete sources, rather than a directional point source, 
beginning at approximately 400 m (deep site) to 1 km (shallow site) 
from the center of the array (Tolstoy et al., 2009), distances that are 
actually greater than four times the calculated 140-m near-field 
distance. Within these distances, the recorded received levels were 
always lower than would be predicted based on calculations that assume 
a directional point source, and increasingly so as one moves closer 
towards the array (Tolstoy et al., 2009). Similarly, the 3,300 in\3\ 
airgun array used in the 3D survey has an approximate diagonal of 17.9 
m, resulting in a near-field distance of 53.5 m at 1 kHz (NSF and USGS, 
2011). Given this, relying on the calculated distances (138.7 m for the 
2D survey and 53.5 m for the 3D survey) as the distances at which we 
expect to be in the near-field is a conservative approach since even 
beyond this distance the acoustic modeling still overestimates the 
actual received level. Within the near-field, in order to explicitly 
evaluate the likelihood of exceeding any particular acoustic threshold, 
one would need to consider the exact position of the animal, its 
relationship to individual array elements, and how the individual 
acoustic sources propagate and their acoustic fields interact. Given 
that within the near-field and dimensions of the array source levels 
would be below those in Table 5, we believe exceedance of the peak 
pressure threshold would only be possible under highly unlikely 
circumstances.
    Therefore, 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 propose to authorize any Level A harassment for 
these species.
    As described previously, no 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 authorized take.

Acoustic Thresholds

    Using the best available science, NMFS has developed acoustic 
thresholds that identify the received level of underwater sound above 
which exposed marine mammals would be reasonably expected to be 
behaviorally harassed (equated to Level B harassment) or to incur PTS 
of some degree (equated to Level A harassment).
    Level B Harassment for non-explosive sources--Though significantly 
driven by received level, the onset of behavioral disturbance from 
anthropogenic noise exposure is also informed to varying degrees by 
other factors related to the source (e.g., frequency, predictability, 
duty cycle), the environment (e.g., bathymetry), and the receiving 
animals (hearing, motivation, experience, demography, behavioral 
context) and can be difficult to predict (Southall et al., 2007, 
Ellison et al., 2012). Based on what the available science indicates 
and the practical need to use a threshold based on a factor that is 
both predictable and measurable for most activities, NMFS uses a 
generalized acoustic threshold based on received level to estimate the 
onset of behavioral harassment. NMFS predicts that marine mammals are 
likely to be behaviorally harassed in a manner we consider Level B 
harassment when exposed to underwater anthropogenic noise above 
received levels of 120 dB re 1 micropascal ([mu]Pa) (root mean square 
(rms)) for continuous (e.g., vibratory pile-driving, drilling) and 
above 160 dB re 1 [mu]Pa (rms) for non-explosive impulsive (e.g., 
seismic airguns) or intermittent (e.g., scientific sonar) sources. L-
DEO's planned activity includes the use of impulsive seismic sources. 
Therefore, the 160 dB re 1 [mu]Pa (rms) criteria is applicable for 
analysis of Level B harassment.
    Level A harassment for non-explosive sources--NMFS' Technical 
Guidance for Assessing the Effects of Anthropogenic Sound on Marine 
Mammal Hearing (Version 2.0) (Technical Guidance, 2018) identifies dual 
criteria to assess auditory injury (Level A harassment) to five 
different marine mammal groups (based on hearing sensitivity) as a 
result of exposure to noise from two different types of sources 
(impulsive or non-impulsive. L-DEO's planned 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 
https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-acoustic-technical-guidance.

                     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.

[[Page 35081]]

 
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 [mu]Pa, and cumulative sound exposure level (LE) has
  a reference value of 1[mu]Pa\2\s. In this Table, thresholds are abbreviated to reflect American National
  Standards Institute standards (ANSI 2013). However, peak sound pressure is defined by ANSI as incorporating
  frequency weighting, which is not the intent for this Technical Guidance. Hence, the subscript ``flat'' is
  being included to indicate peak sound pressure should be flat weighted or unweighted within the generalized
  hearing range. The subscript associated with cumulative sound exposure level thresholds indicates the
  designated marine mammal auditory weighting function (LF, MF, and HF cetaceans, and PW and OW pinnipeds) and
  that the recommended accumulation period is 24 hours. The cumulative sound exposure level thresholds could be
  exceeded in a multitude of ways (i.e., varying exposure levels and durations, duty cycle). When possible, it
  is valuable for action proponents to indicate the conditions under which these acoustic thresholds will be
  exceeded.

Ensonified Area

    Here, we describe operational and environmental parameters of the 
activity that will feed into identifying the area ensonified above the 
acoustic thresholds, which include source levels and transmission loss 
coefficient.
    The planned 3D survey would acquire data with the 18-airgun array 
with a total discharge of 3,300 in\3\ towed at a depth of 10 m. The 
planned 2D survey would acquire data using the 36-airgun array with a 
total discharge of 6,600 in\3\ at a maximum tow depth of 12 m. L-DEO 
model results are used to determine the 160-dBrms radius for the 18-
airgun array, 36-airgun array, and 40-in\3\ airgun in deep water 
(>1,000 m) down to a maximum water depth of 2,000 m. Received sound 
levels were predicted by L-DEO's model (Diebold et al., 2010) which 
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). In 
addition, propagation measurements of pulses from the 36-airgun array 
at a tow depth of 6 m have been reported in deep water (approximately 
1,600 m), intermediate water depth on the slope (approximately 600-
1,100 m), and shallow water (approximately 50 m) in the Gulf of Mexico 
in 2007-2008 (Tolstoy et al. 2009; Diebold et al. 2010).
    For deep and intermediate-water cases, the field measurements 
cannot be used readily to derive Level A and Level B isopleths, as at 
those sites the calibration hydrophone was located at a roughly 
constant depth of 350-500 m, which may not intersect all the sound 
pressure level (SPL) isopleths at their widest point from the sea 
surface down to the maximum relevant water depth for marine mammals of 
~2,000 m. At short ranges, where the direct arrivals dominate and the 
effects of seafloor interactions are minimal, the data recorded at the 
deep and slope sites are suitable for comparison with modeled levels at 
the depth of the calibration hydrophone. At longer ranges, the 
comparison with the model--constructed from the maximum SPL through the 
entire water column at varying distances from the airgun array--is the 
most relevant.
    In deep and intermediate-water depths, comparisons at short ranges 
between sound levels for direct arrivals recorded by the calibration 
hydrophone and model results for the same array tow depth are in good 
agreement (Fig. 12 and 14 in Appendix H of NSF-USGS, 2011). 
Consequently, isopleths falling within this domain can be predicted 
reliably by the L-DEO model, although they may be imperfectly sampled 
by measurements recorded at a single depth. At greater distances, the 
calibration data show that seafloor-reflected and sub-seafloor-
refracted arrivals dominate, whereas the direct arrivals become weak 
and/or incoherent. Aside from local topography effects, the region 
around the critical distance is where the observed levels rise closest 
to the model curve. However, the observed sound levels are found to 
fall almost entirely below the model curve. Thus, analysis of the Gulf 
of Mexico calibration measurements demonstrates that although simple, 
the L-DEO model is a robust tool for conservatively estimating 
isopleths.
    For deep water (>1,000 m), L-DEO used the deep-water radii obtained 
from model results down to a maximum water depth of 2000 m. The radii 
for intermediate water depths (100-1,000 m) were derived from the deep-
water ones by applying a correction factor (multiplication) of 1.5, 
such that observed levels at very near offsets fall below the corrected 
mitigation curve (See Fig. 16 in Appendix H of NSF-USGS, 2011).
    Measurements have not been reported for the single 40-in\3\ airgun. 
L-DEO model results are used to determine the 160-dB (rms) radius for 
the 40-in\3\ airgun at a 12 m tow depth in deep water (See LGL 2018, 
Figure A-2). For intermediate-water depths, a correction factor of 1.5 
was applied to the deep-water model results.
    L-DEO's modeling methodology is described in greater detail in the 
IHA application (LGL 2018). The estimated distances to the Level B 
harassment isopleth for the Langseth's 18-airgun array, 36-airgun 
array, and single 40-in\3\ airgun are shown in Table 4.

Table 4--Predicted Radial Distances From R/V Langseth Seismic Sources to
         Isopleths Corresponding to Level B Harassment Threshold
------------------------------------------------------------------------
                                                           Distance  (m)
            Source and volume             Tow depth  (m)        \a\
------------------------------------------------------------------------
Single Bolt airgun (40 in\3\)...........              12             431
2 strings, 18 airguns (3,300 in\3\).....              10           3,758

[[Page 35082]]

 
4 strings, 36 airguns (6,600 in\3\).....              12           6,733
------------------------------------------------------------------------
\a\ Distance based on L-DEO model results.

    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 software program and the 
NMFS User Spreadsheet, described below. The updated acoustic thresholds 
for impulsive sounds (e.g., airguns) contained in the Technical 
Guidance were presented as dual metric acoustic thresholds using both 
SELcum and peak sound pressure metrics (NMFS 2016). As dual 
metrics, NMFS considers onset of PTS (Level A harassment) to have 
occurred when either one of the two metrics is exceeded (i.e., metric 
resulting in the largest isopleth). The SELcum metric 
considers both level and duration of exposure, as well as auditory 
weighting functions by marine mammal hearing group. In recognition of 
the fact that the requirement to calculate Level A harassment 
ensonified areas could be more technically challenging to predict due 
to the duration component and the use of weighting functions in the new 
SELcum thresholds, NMFS developed an optional User 
Spreadsheet that includes tools to help predict a simple isopleth that 
can be used in conjunction with marine mammal density or occurrence to 
facilitate the estimation of take numbers.
    The values for SELcum and peak SPL for the Langseth 
airgun array were derived from calculating the modified far-field 
signature (Table 5). 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 Level B harassment 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.
    For a more complete explanation of this modeling approach, please 
see ``Appendix A: Determination of Mitigation Zones'' in the IHA 
application.

   Table 5--Modeled Source Levels Based on Modified Farfield Signature for the R/V Langseth 3,300 in\3\ Airgun
                           Array, 6,600 in\3\ Airgun Array, and Single 40 in\3\ Airgun
----------------------------------------------------------------------------------------------------------------
                                                                       High           Phocid          Otariid
                                  Low  frequency  Mid  frequency     frequency       pinnipeds       pinnipeds
                                     cetaceans       cetaceans       cetaceans     (underwater)    (underwater)
                                  (Lpk,flat: 219  (Lpk,flat: 230  (Lpk,flat: 202  (Lpk,flat: 218  (Lpk,flat: 232
                                  dB; LE,LF,24h:  dB; LE,MF,24h:  dB; LE,HF,24h:  dB; LE,HF,24h:  dB; LE,HF,24h:
                                      183 dB)         185 dB)         155 dB)         185 dB)         203 dB)
 
----------------------------------------------------------------------------------------------------------------
3,300 in\3\ airgun array (Peak            245.29          250.97          243.61          246.00          251.92
 SPLflat).......................
3.300 in\3\ airgun array                  226.38          226.33          226.66          226.33          227.07
 (SELcum).......................
6,600 in\3\ airgun array (Peak            252.06          252.65          253.24          252.25          252.52
 SPLflat).......................
6,600 in\3\ airgun array                  232.98          232.84          233.10          232.84          232.08
 (SELcum).......................
40 in\3\ airgun (Peak SPLflat)..          223.93          224.09          223.92          223.95          223.95
40 in\3\ airgun (SELcum)........          202.99          202.89          204.37          202.89          202.35
----------------------------------------------------------------------------------------------------------------

    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 
hertz (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 source

[[Page 35083]]

velocities and shot intervals specific to each of the three planned 
surveys provided in the IHA application, potential radial distances to 
auditory injury zones were then calculated for SELcum 
thresholds.
    Inputs to the User Spreadsheets in the form of estimated SLs are 
shown in Table 5. User Spreadsheets used by L-DEO to estimate distances 
to Level A harassment isopleths for the 18-airgun array, 36-airgun 
array, and single 40 in\3\ airgun for the surveys are shown in Tables 
A-3, A-6, and A-10 in Appendix A of the IHA application. Outputs from 
the User Spreadsheets in the form of estimated distances to Level A 
harassment isopleths for the surveys are shown in Table 6. 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 6--Modeled Radial Distances (m) to Isopleths Corresponding to Level A Harassment Thresholds
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                                                              Phocid          Otariid
             Source and volume                                             LF  cetaceans   MF  cetaceans   HF  cetaceans     pinnipeds       pinnipeds
--------------------------------------------------------------------------------------------------------------------------------------------------------
Single Bolt airgun (40 in\3\) \a\.........  PTS SELcum..................             0.5               0               0               0               0
                                            PTS Peak....................            1.76            0.51            12.5            1.98             0.4
2 strings, 18 airguns (3300 in\3\)........  PTS SELcum..................            75.6               0             0.3             2.9               0
                                            PTS Peak....................            23.2            11.8           118.7            25.1             9.9
4 strings, 36 airguns (6600 in\3\)........  PTS SELcum..................           426.9               0             1.3            13.9               0
                                            PTS Peak....................            38.9            13.6           268.3            43.7            10.6
--------------------------------------------------------------------------------------------------------------------------------------------------------

    Note that because of some of the assumptions included in the 
methods used, isopleths produced may be overestimates to some degree, 
which will ultimately result in some degree of overestimate 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 the planned 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.

Marine Mammal Occurrence

    In this section we provide the information about the presence, 
density, or group dynamics of marine mammals that will inform the take 
calculations.
    In developing their IHA application, L-DEO utilized estimates of 
cetacean densities in the survey area synthesized by Barlow (2016). 
Observations from NMFS Southwest Fisheries Science Center (SWFSC) ship 
surveys off of Oregon and Washington (up to 556 km from shore) between 
1991 and 2014 were pooled. Systematic, offshore, at-sea survey data for 
pinnipeds are more limited. To calculate pinniped densities in the 
survey area, L-DEO utilized methods described in U.S. Navy (2010) which 
calculated density estimates for pinnipeds off Washington at different 
times of the year using information on breeding and migration, 
population estimates from shore counts, and areas used by different 
species while at sea. The densities calculated by the Navy were updated 
by L-DEO using stock abundances presented in the latest SARs (e.g., 
Caretta et al., 2018).
    While the IHA application was in review by NMFS, the U.S. Navy 
published the Marine Species Density Database Phase III for the 
Northwest Training and Testing (NWTT) Study Area (Navy 2018). The 
planned geophysical survey area is located near the western boundary of 
the defined NWTT Offshore Study Area.
    For several cetacean species, the Navy updated densities estimated 
by line-transect surveys or mark-recapture studies (e.g., Barlow 2016). 
These methods usually produce a single value for density that is an 
averaged estimate across very large geographical areas, such as waters 
within the U.S. EEZ off California, Oregon, and Washington (referred to 
as a ``uniform'' density estimate). This is the general approach 
applied in estimating cetacean abundance in the NMFS stock assessment 
reports. The disadvantage of these methods is that they do not provide 
information on varied concentrations of species in sub-regions of very 
large areas, and do not estimate density for other seasons or 
timeframes that were not surveyed. More recently, a newer method called 
spatial habitat modeling has been used to estimate cetacean densities 
that address some of these shortcomings (e.g., Barlow et al., 2009; 
Becker et al., 2010; 2012a; 2014; Becker et al., 2016; Ferguson et al., 
2006; Forney et al., 2012; 2015; Redfern et al., 2006). (Note that 
spatial habitat models are also referred to as ``species distribution 
models'' or ``habitat-based density models.'') These models estimate 
density as a continuous function of habitat variables (e.g., sea 
surface temperature, seafloor depth) and thus, within the study area 
that was modeled, densities can be predicted at all locations where 
these habitat variables can be measured or estimated. Spatial habitat 
models therefore allow estimates of cetacean densities on finer scales 
than traditional line-transect or mark-recapture analyses.
    The methods used to estimate pinniped at-sea densities are 
typically different than those used for cetaceans, because pinnipeds 
are not limited to the water and spend a significant amount of time on 
land (e.g., at rookeries). Pinniped abundance is generally estimated 
via shore counts of animals on land at known haulout sites or by 
counting number of pups weaned at rookeries and applying a correction 
factor to estimate the abundance of the population (for example Harvey 
et al., 1990; Jeffries et al., 2003; Lowry, 2002; Sepulveda et al., 
2009). Estimating in-water densities from land-based counts is 
difficult given the variability in foraging ranges, migration, and 
haulout behavior between species and within each species, and is driven 
by factors such as age class, sex class, breeding cycles, and seasonal 
variation. Data such as age class, sex class, and seasonal variation 
are often used in conjunction with abundance estimates from known 
haulout sites to assign an in-water abundance estimate for a given 
area. The total abundance divided by the area of the region provides a 
representative in-water density estimate for each species in a 
different location, which enables analyses of in-water stressors 
resulting from at-sea Navy testing or training activities. In addition 
to using

[[Page 35084]]

shore counts to estimate pinniped density, traditional line-transect 
derived estimates are also used, particularly in open ocean areas.
    Because the Navy's density calculations for many species included 
spatial habitat modeling and demographic information, we utilized the 
Navy Marine Species Density Database (NMSDD) to estimate densities and 
resulting take of marine mammals from the planned geophysical survey. 
Where available, the appropriate seasonal density estimate from the 
NMSDD was used in the estimation here (i.e., summer). For species with 
a quantitative density range within or around the planned survey area, 
the maximum presented density was conservatively used. Background 
information on the density calculations for each species/guild as well 
as reported sightings in nearby waters are reported here. Density 
estimates for each species/guild are found in Table 7.
Humpback Whale
    NMFS SWFSC developed a CCE habitat-based density model for humpback 
whales which provides spatially explicit density estimates off the U.S. 
West Coast for summer and fall based on survey data collected between 
1991 and 2014 (Becker et al., in prep). Density data are not available 
for the NWTT Offshore area northwest of the SWFSC strata, so the 
habitat-based density values in the northernmost pixels adjoining this 
region were interpolated based on the nearest-neighbor approach to 
provide representative density estimates for this area.
    Six humpback whale sightings (8 animals) were made off Washington/
Oregon during the June-July 2012 L-DEO Juan de Fuca plate seismic 
survey; all were well inshore of the planned survey area (RPS 2012b). 
There were 98 humpback whale sightings (213 animals) made during the 
July 2012 L-DEO seismic survey off southern Washington, northeast of 
the planned survey area (RPS 2012a), and 11 sightings (23 animals) 
during the July 2012 L-DEO seismic survey off Oregon, southeast of the 
planned survey area (RPS 2012c). No sightings were made near the 
planned survey area in the 2014 NMFS Southwest Fisheries Science Center 
(SWFSC) California Current Ecosystem (CCE) vessel survey (Barlow 2016).
Minke Whale
    Density values for minke whales are available for the SWFSC Oregon/
Washington and Northern California offshore strata for summer/fall 
(Barlow, 2016). Density data are not available for the NWTT Offshore 
area northwest of the SWFSC strata, so data from the SWFSC Oregon/
Washington stratum were used as representative estimates.
    Sightings have been made off Oregon and Washington in shelf and 
deeper waters (Green et al. 1992; Adams et al. 2014; Carretta et al. 
2017). An estimated abundance of 211 minke whales was reported for the 
Oregon/Washington region based on sightings data from 1991-2005 (Barlow 
and Forney 2007), whereas a 2008 survey did not record any minke whales 
while on survey effort (Barlow 2010). The abundance for Oregon/
Washington for 2014 was estimated at 507 minke whales (Barlow 2016). 
There were no sightings of minke whales off Washington/Oregon during 
the June-July 2012 L-DEO Juan de Fuca plate seismic survey or during 
the July 2012 L-DEO seismic survey off Oregon, southeast of the planned 
survey area (RPS 2012b,c). One minke whale was seen during the July 
2012 L-DEO seismic survey off southern Washington, north of the planned 
survey area (RPS 2012a). No sightings of minke whales were made near 
the planned survey area during the 2014 SWFSC CCE vessel survey (Barlow 
2016).
Sei Whale
    Density values for sei whales are available for the SWFSC Oregon/
Washington and Northern California offshore strata for summer/fall 
(Barlow, 2016). Density data are not available for the NWTT Offshore 
area northwest of the SWFSC strata, so data from the SWFSC Oregon/
Washington stratum were used as representative estimates.
    Sei whales are rare in the waters off California, Oregon, and 
Washington (Brueggeman et al. 1990; Green et al. 1992; Barlow 1994, 
1997). Only 16 confirmed sightings were reported for California, 
Oregon, and Washington during extensive surveys from 1991-2014 (Green 
et al. 1992, 1993; Hill and Barlow 1992; Carretta and Forney 1993; 
Mangels and Gerrodette 1994; Von Saunder and Barlow 1999; Barlow 2003; 
Forney 2007; Barlow 2010; Carretta et al. 2017). Based on surveys 
conducted in 1991-2008, the estimated abundance of sei whales off the 
coasts of Oregon and Washington was 52 (Barlow 2010); for 2014, the 
abundance estimate was 468 (Barlow 2016). Two sightings of four 
individuals were made during the June-July 2012 L-DEO Juan de Fuca 
plate seismic survey off Washington/Oregon (RPS 2012b); these were well 
inshore of the planned survey area (~125[deg] W). No sei whales were 
sighted during the July 2012 L-DEO seismic surveys north and south of 
the planned survey area (RPS 2012a,c).
Fin Whale
    NMFS SWFSC developed a CCE habitat-based density model for fin 
whales which provides spatially explicit density estimates off the U.S. 
West Coast for summer and fall based on survey data collected between 
1991 and 2014 (Becker et al., in prep). Density data are not available 
for the NWTT Offshore area northwest of the SWFSC strata, so the 
habitat-based density values in the northernmost pixels adjoining this 
region were interpolated based on the nearest-neighbor approach to 
provide representative density estimates for this area.
    Fin whales are routinely sighted during surveys off Oregon and 
Washington (Barlow and Forney 2007; Barlow 2010; Adams et al. 2014; 
Calambokidis et al. 2015; Edwards et al. 2015; Carretta et al. 2017), 
including in coastal as well as offshore waters. They have also been 
detected acoustically near the planned study area during June-August 
(Edwards et al. 2015). There is one sighting of a fin whale in the 
Ocean Biogeographic Information System (OBIS) database within the 
planned survey area, which was made in August 2005 during the SWFSC 
Collaborative Survey of Cetacean Abundance and the Pelagic Ecosystem 
(CSCAPE) Marine Mammal Survey, and several other sightings in adjacent 
waters (OBIS 2018). Eight fin whale sightings (19 animals) were made 
off Washington/Oregon during the June-July 2012 L-DEO Juan de Fuca 
plate seismic survey, including two sightings (4 animals) in the 
vicinity of the planned survey area; sightings were made in waters 
2,369-3,940 m deep (RPS 2012b). Fourteen fin whale sightings (28 
animals) were made during the July 2012 L-DEO seismic surveys off 
southern Washington, northeast of the planned survey area (RPS 2012a). 
No fin whales were sighted during the July 2012 L-DEO seismic survey 
off Oregon, southeast of the planned survey area (RPS 2012c). Fin 
whales were also seen off southern Oregon during July 2012 in water 
>2,000 m deep during surveys by Adams et al. (2014).
Blue Whale
    NMFS SWFSC developed a CCE habitat-based density model for blue 
whales which provides spatially explicit density estimates off the U.S. 
West Coast for summer and fall based on survey data collected between 
1991 and 2014 (Becker et al., in prep). Density data are not available 
for the NWTT Offshore area northwest of the SWFSC

[[Page 35085]]

strata, so the habitat-based density values in the northernmost pixels 
adjoining this region were interpolated based on the nearest-neighbor 
approach to provide representative density estimates for this area.
    The nearest sighting of blue whales is ~55 km to the southwest 
(OBIS 2018), and there are several other sightings in adjacent waters 
(Carretta et al. 2018; OBIS 2018). Satellite telemetry suggests that 
blue whales are present in waters offshore of Oregon and Washington 
during fall and winter (Bailey et al. 2009; Hazen et al. 2017).
Sperm Whale
    NMFS SWFSC developed a CCE habitat-based density model for sperm 
whales which provides spatially explicit density estimates off the U.S. 
West Coast for summer and fall based on survey data collected between 
1991 and 2014 (Becker et al., in prep). Density data are not available 
for the NWTT Offshore area northwest of the SWFSC strata, so the 
habitat-based density values in the northernmost pixels adjoining this 
region were interpolated based on the nearest-neighbor approach to 
provide representative density estimates for this area.
    There is one sighting of a sperm whale in the vicinity of the 
survey area in the OBIS database that was made in July 1996 during the 
SWFSC ORCAWALE Marine Mammal Survey (OBIS 2018), and several other 
sightings in adjacent waters (Carretta et al. 2018; OBIS 2018). Sperm 
whale sightings were also made in the vicinity of the planned survey 
area during the 2014 SWFSC vessel survey (Barlow 2016). A single sperm 
whale was sighted during the 2009 ETOMO survey, north of the planned 
survey area (Holst 2017). Sperm whales were detected acoustically in 
waters near the planned survey area in August 2016 during the SWFSC 
Passive Acoustics Survey of Cetacean Abundance Levels (PASCAL) study 
using drifting acoustic recorders (Keating et al. 2018).
Pygmy and Dwarf Sperm Whales (Kogia Guild)
    Kogia species are treated as a guild off the U.S. West Coast 
(Barlow & Forney, 2007). Barlow (2016) provided stratified density 
estimates for Kogia spp. for waters off California, Oregon, and 
Washington; these were used for all seasons for both the Northern 
California and Oregon/Washington strata. In the absence of other data, 
the Barlow (2016) Oregon/Washington estimate was also used for the area 
northwest of the SWFSC strata for all seasons.
    Pygmy and dwarf sperm whales are rarely sighted off Oregon and 
Washington, with only one sighting of an unidentified Kogia sp. beyond 
the U.S. EEZ, during the 1991-2014 NOAA vessel surveys (Carretta et al. 
2017). This sighting was made in October 1993 during the SWFSC PODS 
Marine Mammal Survey ~150 km to the south of the planned survey area 
(OBIS 2018). Norman et al. (2004) reported eight confirmed stranding 
records of pygmy sperm whales for Oregon and Washington, five of which 
occurred during autumn and winter.
Baird's Beaked Whale
    NMFS SWFSC developed a CCE habitat-based density model for Baird's 
beaked whale which provides spatially explicit density estimates off 
the U.S. West Coast for summer and fall based on survey data collected 
between 1991 and 2014 (Becker et al., in prep). Density data are not 
available for the NWTT Offshore area northwest of the SWFSC strata, so 
the habitat-based density values in the northernmost pixels adjoining 
this region were interpolated based on the nearest-neighbor approach to 
provide representative density estimates for this area.
    Green et al. (1992) sighted five groups during 75,050 km of aerial 
survey effort in 1989-1990 off Washington/Oregon spanning coastal to 
offshore waters: Two in slope waters and three in offshore waters. Two 
groups were sighted during summer/fall 2008 surveys off Washington/
Oregon, in waters >2,000 m deep (Barlow 2010). Acoustic monitoring 
offshore Washington detected Baird's beaked whale pulses during January 
through November 2011, with peaks in February and July 
([Scirc]irovi[cacute] et al. 2012b in USN 2015). Baird's beaked whales 
were detected acoustically near the planned survey area in August 2016 
during the SWFSC PASCAL study using drifting acoustic recorders 
(Keating et al. 2018). There is one sighting of a Baird's beaked whale 
near the survey area in the OBIS database that was made in August 2005 
during the SWFSC CSCAPE Marine Mammal Survey (OBIS 2018).
Small Beaked Whale Guild
    NMFS has developed habitat-based density models for a small beaked 
whale guild in the CCE (Becker et al., 2012b; Forney et al., 2012). The 
small beaked whale guild includes Cuvier's beaked whale and beaked 
whales of the genus Mesoplodon, including Blainville's beaked whale, 
Hubbs' beaked whale, and Stejneger's beaked whale. NMFS SWFSC developed 
a CCE habitat-based density model for the small beaked whale guild 
which provides spatially explicit density estimates off the U.S. West 
Coast for summer and fall based on survey data collected between 1991 
and 2014 (Becker et al., in prep). Density data are not available for 
the NWTT Offshore area northwest of the SWFSC strata, so the habitat-
based density values in the northernmost pixels adjoining this region 
were interpolated based on the nearest-neighbor approach to provide 
representative density estimates for this area.
    Four beaked whale sightings were reported in water depths >2,000 m 
off Oregon/Washington during surveys in 2008 (Barlow 2010). None were 
seen in 1996 or 2001 (Barlow 2003), and several were recorded from 1991 
to 1995 (Barlow 1997). One Cuvier's beaked whale sighting was made east 
of the planned survey area during 2014 (Barlow 2016). Acoustic 
monitoring in Washington offshore waters detected Cuvier's beaked whale 
pulses between January and November 2011 ([Scirc]irovi[cacute] et al. 
2012b in USN 2015). There is one sighting of a Cuvier's beaked whale 
near the planned survey area in the OBIS database that was made in July 
1996 during the SWFSC ORCAWALE Marine Mammal Survey (OBIS 2018), and 
several other sightings were made in adjacent waters, primarily to the 
south and east of the planned survey area (Carretta et al. 2018; OBIS 
2018). Cuvier's beaked whales were detected acoustically in waters near 
the planned survey area in August 2016 during the SWFSC PASCAL study 
using drifting acoustic recorders (Keating et al. 2018).
    There are no sightings of Blainville's beaked whales near the 
planned survey area in the OBIS database (OBIS 2018). There is one 
sighting of an unidentified species of Mesoplodont whale near the 
survey area in the OBIS database that was made in July 1996 during the 
SWFSC ORCAWALE Marine Mammal Survey (OBIS 2018). There was one acoustic 
encounter with Blainville's beaked whales recorded in Quinault Canyon 
off Washington in waters 1,400 m deep during 2011 (Baumann-Pickering et 
al. 2014). Blainville's beaked whales were not detected acoustically in 
waters near the planned survey area in August 2016 during the SWFSC 
PASCAL study using drifting acoustic recorders (Keating et al. 2018). 
Although Blainville's beaked whales could be encountered during the 
planned survey, an encounter would be unlikely because the planned 
survey area is beyond the northern limits of this tropical species' 
usual distribution.

[[Page 35086]]

    Stejneger's beaked whale calls were detected during acoustic 
monitoring offshore Washington between January and June 2011, with an 
absence of calls from mid-July to November 2011 ([Scirc]irovi[cacute] 
et al. 2012b in USN 2015). Analysis of these data suggest that this 
species could be more than twice as prevalent in this area than Baird's 
beaked whale (Baumann-Pickering et al. 2014). Stejneger's beaked whales 
were also detected acoustically in waters near the planned survey area 
in August 2016 during the SWFSC PASCAL study using drifting acoustic 
recorders (Keating et al. 2018). There are no sightings of Stejneger's 
beaked whales near the planned survey area in the OBIS database (OBIS 
2018). There is one sighting of an unidentified species of Mesoplodont 
beaked whale near the survey area in the OBIS database that was made 
during July 1996 during the SWFSC ORCAWALE Marine Mammal Survey (OBIS 
2018).
    Baird's beaked whale is sometimes seen close to shore where deep 
water approaches the coast, but its primary habitat is over or near the 
continental slope and oceanic seamounts (Jefferson et al. 2015). Along 
the U.S. West Coast, Baird's beaked whales have been sighted primarily 
along the continental slope (Green et al. 1992; Becker et al. 2012; 
Carretta et al. 2018) from late spring to early fall (Green et al. 
1992). The whales move out from those areas in winter (Reyes 1991). In 
the eastern North Pacific Ocean, Baird's beaked whales apparently spend 
the winter and spring far offshore, and in June, they move onto the 
continental slope, where peak numbers occur during September and 
October. Green et al. (1992) noted that Baird's beaked whales on the 
U.S. West Coast were most abundant in the summer, and were not sighted 
in the fall or winter. MacLeod et al. (2006) reported numerous 
sightings and strandings of Berardius spp. off the U.S. West Coast.
Bottlenose Dolphin
    During surveys off the U.S. West Coast, offshore bottlenose 
dolphins were generally found at distances greater than 1.86 miles (3 
km) from the coast and were most abundant off southern California 
(Barlow, 2010, 2016). Based on sighting data collected by SWFSC during 
systematic surveys in the Northeast Pacific between 1986 and 2005, 
there were few sightings of offshore bottlenose dolphins north of about 
40[deg] N (Hamilton et al., 2009). NMFS SWFSC developed a CCE habitat-
based density model for bottlenose dolphins which provides spatially 
explicit density estimates off the U.S. West Coast for summer and fall 
based on survey data collected between 1991 and 2014 (Becker et al., in 
prep). Density data are not available for the NWTT Offshore area 
northwest of the SWFSC strata, so the habitat-based density values in 
the northernmost pixels adjoining this region were interpolated based 
on the nearest-neighbor approach to provide representative density 
estimates for this area.
    Bottlenose dolphins occur frequently off the coast of California, 
and sightings have been made as far north as 41[deg] N, but few records 
exist for Oregon/Washington (Carretta et al. 2017). Three sightings and 
one stranding of bottlenose dolphins have been documented in Puget 
Sound since 2004 (Cascadia Research 2011 in USN 2015). It is possible 
that offshore bottlenose dolphins may range as far north as the planned 
survey area during warm-water periods (Carretta et al. 2017). Adams et 
al. (2014) made one sighting off Washington during September 2012. 
There are no sightings of bottlenose dolphins near the planned survey 
area in the OBIS database (OBIS 2018).
Striped Dolphin
    Striped dolphin encounters increase in deep, relatively warmer 
waters off the U.S. West Coast, and their abundance decreases north of 
about 42[deg] N (Barlow et al., 2009; Becker et al., 2012b; Becker et 
al., 2016; Forney et al., 2012). Although striped dolphins typically do 
not occur north of California, there are a few sighting records off 
Oregon and Washington (Barlow, 2003, 2010; Von Saunder & Barlow, 1999), 
and multiple sightings in 2014 when water temperatures were anomalously 
warm (Barlow, 2016). NMFS SWFSC developed a CCE habitat-based density 
model for striped dolphins which provides spatially explicit density 
estimates off the U.S. West Coast for summer and fall based on survey 
data collected between 1991 and 2014 (Becker et al., in prep). Density 
data are not available for the NWTT Offshore area northwest of the 
SWFSC strata, so the habitat-based density values in the northernmost 
pixels adjoining this region were interpolated based on the nearest-
neighbor approach to provide representative density estimates for this 
area.
    Striped dolphins regularly occur off California (Becker et al. 
2012), where they have been seen as far as the ~300 n.mi. limit during 
the NOAA Fisheries vessel surveys (Carretta et al. 2017). Strandings 
have occurred along the coasts of Oregon and Washington (Carretta et 
al. 2016). During surveys off the U.S. West Coast in 2014, striped 
dolphins were seen as far north as 44[deg] N (Barlow 2016).
Short-Beaked Common Dolphin
    Short-beaked common dolphins are found off the U.S. West Coast 
throughout the year, distributed between the coast and at least 345 
miles (556 km) from shore (Barlow, 2010; Becker et al., 2017; Carretta 
et al., 2017b). The short-beaked common dolphin is the most abundant 
cetacean species off California (Barlow, 2016; Carretta et al., 2017b; 
Forney et al., 1995); however, their abundance decreases dramatically 
north of about 40[deg] N (Barlow et al., 2009; Becker et al., 2012c; 
Becker et al., 2016; Forney et al., 2012). Short-beaked common dolphins 
are occasionally sighted in waters off Oregon and Washington, and one 
group of approximately 40 short-beaked common dolphins was sighted off 
northern Washington in 2005 at about 48[deg] N (Forney, 2007), and 
multiple groups were sighted as far north as 44[deg] N during 
anomalously warm conditions in 2014 (Barlow, 2016). NMFS SWFSC 
developed a CCE habitat-based density model for short-beaked common 
dolphins which provides spatially explicit density estimates off the 
U.S. West Coast for summer and fall based on survey data collected 
between 1991 and 2014 (Becker et al., in prep). Density data are not 
available for the NWTT Offshore area northwest of the SWFSC strata, so 
the habitat-based density values in the northernmost pixels adjoining 
this region were interpolated based on the nearest-neighbor approach to 
provide representative density estimates for this area.
    There are no sightings of short-beaked dolphins near the planned 
survey area in the OBIS database (OBIS 2018).
Pacific White-Sided Dolphin
    Pacific white-sided dolphins occur year-round in the offshore 
region of the NWTT Study Area, with increased abundance in the summer/
fall (Barlow, 2010; Forney & Barlow, 1998; Oleson et al., 2009). NMFS 
SWFSC developed a CCE habitat-based density model for Pacific white-
sided dolphins which provides spatially explicit density estimates off 
the U.S. West Coast for summer and fall based on survey data collected 
between 1991 and 2014 (Becker et al., in prep). Density data are not 
available for the NWTT Offshore area northwest of the SWFSC strata, so 
the habitat-based density values in the northernmost pixels adjoining 
this region were interpolated based on the nearest-neighbor approach to 
provide

[[Page 35087]]

representative density estimates for this area.
    Fifteen Pacific white-sided dolphin sightings (231 animals) were 
made off Washington/Oregon during the June-July 2012 L-DEO Juan de Fuca 
plate seismic survey; none were near the planned survey area (RPS 
2012b). There were fifteen Pacific white-sided dolphin sightings (462 
animals) made during the July 2012 L-DEO seismic surveys off southern 
Washington, northeast of the planned survey area (RPS 2012a). This 
species was not sighted during the July 2012 L-DEO seismic survey off 
Oregon, southeast of the planned survey area (RPS 2012c). One group of 
10 Pacific white-sided dolphins was sighted during the 2009 ETOMO 
survey north of the planned survey area (Holst 2017).
Northern Right Whale Dolphin
    Survey data suggest that, at least in the eastern North Pacific, 
seasonal inshore-offshore and north-south movements are related to prey 
availability, with peak abundance in the Southern California Bight 
during winter and distribution shifting northward into Oregon and 
Washington as water temperatures increase during late spring and summer 
(Barlow, 1995; Becker et al., 2014; Forney et al., 1995; Forney & 
Barlow, 1998; Leatherwood & Walker, 1979). NMFS SWFSC developed a CCE 
habitat-based density model for northern right whale dolphins which 
provides spatially explicit density estimates off the U.S. West Coast 
for summer and fall based on survey data collected between 1991 and 
2014 (Becker et al., in prep). Density data are not available for the 
NWTT Offshore area northwest of the SWFSC strata, so the habitat-based 
density values in the northernmost pixels adjoining this region were 
interpolated based on the nearest-neighbor approach to provide 
representative density estimates for this area.
    Seven northern right whale dolphin sightings (231 animals) were 
made off Washington/Oregon during the June-July 2012 L-DEO Juan de Fuca 
plate seismic survey; none were seen near the planned survey area (RPS 
2012b). There were eight northern right whale dolphin sightings (278 
animals) made during the July 2012 L-DEO seismic surveys off southern 
Washington, northeast of the planned survey area (RPS 2012a). This 
species was not sighted during the July 2012 L-DEO seismic survey off 
Oregon, southeast of the planned survey area (RPS 2012c).
Risso's Dolphin
    NMFS SWFSC developed a CCE habitat-based density model for Risso's 
dolphins which provides spatially explicit density estimates off the 
U.S. West Coast for summer and fall based on survey data collected 
between 1991 and 2014 (Becker et al., in prep). Density data are not 
available for the NWTT Offshore area northwest of the SWFSC strata, so 
the habitat-based density values in the northernmost pixels adjoining 
this region were interpolated based on the nearest-neighbor approach to 
provide representative density estimates for this area.
    Two sightings of 38 individuals were recorded off Washington from 
August 2004 to September 2008 (Oleson et al. 2009). Risso's dolphins 
were sighted off Oregon, in June and October 2011 (Adams et al. 2014). 
There were three Risso's dolphin sightings (31 animals) made during the 
July 2012 L-DEO seismic surveys off southern Washington, northeast of 
the planned survey area (RPS 2012a). This species was not sighted 
during the July 2012 L-DEO seismic survey off Oregon, southeast of the 
planned survey area (RPS 2012c), or off Washington/Oregon during the 
June-July 2012 L-DEO Juan de Fuca plate seismic survey (RPS 2012b).
False Killer Whale
    False killer whales were not included in the NMSDD, as they are 
very rarely encountered in the northeast Pacific. Density estimates for 
false killer whales were also not presented in Barlow (2016), as no 
sightings occurred during surveys conducted between 1986 and 2008 
(Ferguson and Barlow 2001, 2003; Forney 2007; Barlow 2003, 2010). One 
sighting was made off of southern California during 2014 (Barlow 2016). 
There are no sightings of false killer whales near the survey area in 
the OBIS database (OBIS 2018).
Killer Whale
    Due to the difficulties associated with reliably distinguishing the 
different stocks of killer whales from at-sea sightings, density 
estimates for the Offshore region of the NWTT Study Area are presented 
for the species as a whole (i.e., includes the Offshore, West Coast 
Transient, Northern Resident, and Southern Resident stocks). Density 
values for killer whales are available for the SWFSC Oregon/Washington 
and Northern California offshore strata for summer/fall (Barlow, 2016). 
Density data are not available for the NWTT Offshore area northwest of 
the SWFSC strata, so data from the SWFSC Oregon/Washington stratum were 
used as representative estimates. These values were used to represent 
density year-round.
    Eleven sightings of ~536 individuals were reported off Oregon/
Washington during the 2008 SWFSC vessel survey (Barlow 2010). Killer 
whales were sighted offshore Washington during surveys from August 2004 
to September 2008 (Oleson et al. 2009). Keating et al. (2015) analyzed 
cetacean whistles from recordings made during 2000-2012; several killer 
whale acoustic detections were made offshore Washington.
Short-Finned Pilot Whale
    Along the U.S. West Coast, short-finned pilot whales were once 
common south of Point Conception, California (Carretta et al., 2017b; 
Reilly & Shane, 1986), but now sightings off the U.S. West Coast are 
infrequent and typically occur during warm water years (Carretta et 
al., 2017b). Stranding records for this species from Oregon and 
Washington waters are considered to be beyond the normal range of this 
species rather than an extension of its range (Norman et al., 2004). 
Density values for short-finned pilot whales are available for the 
SWFSC Oregon/Washington and Northern California strata for summer/fall 
(Barlow, 2016). Density data are not available for the NWTT Offshore 
area northwest of the SWFSC strata, so data from the SWFSC Oregon/
Washington stratum were used as representative estimates. These values 
were used to represent density year-round.
    Few sightings were made off California/Oregon/Washington in 1984-
1992 (Green et al. 1992; Carretta and Forney 1993; Barlow 1997), and 
sightings remain rare (Barlow 1997; Buchanan et al. 2001; Barlow 2010). 
No short-finned pilot whales were seen during surveys off Oregon and 
Washington in 1989-1990, 1992, 1996, and 2001 (Barlow 2003). A few 
sightings were made off California during surveys in 1991-2014 (Barlow 
2010). Carretta et al. (2017) reported one sighting off Oregon during 
1991-2008. Several stranding events in Oregon/southern Washington have 
been recorded over the past few decades, including in March 1996, June 
1998, and August 2002 (Norman et al. 2004).
Dall's Porpoise
    NMFS SWFSC developed a CCE habitat-based density model for Dall's 
porpoise which provides spatially explicit density estimates off the 
U.S. West Coast for summer and fall based on survey data collected 
between 1991 and 2014 (Becker et al., in prep). Density data are not 
available for the NWTT Offshore area northwest of the SWFSC strata, so 
the habitat-based

[[Page 35088]]

density values in the northernmost pixels adjoining this region were 
interpolated based on the nearest-neighbor approach to provide 
representative density estimates for this area.
    Oleson et al. (2009) reported 44 sightings of 206 individuals off 
Washington during surveys form August 2004 to September 2008. Dall's 
porpoise were seen in the waters off Oregon during summer, fall, and 
winter surveys in 2011 and 2012 (Adams et al. 2014). Nineteen Dall's 
porpoise sightings (144 animals) were made off Washington/Oregon during 
the June-July 2012 L-DEO Juan de Fuca plate seismic survey; none were 
in near the planned survey area (RPS 2012b). There were 16 Dall's 
porpoise sightings (54 animals) made during the July 2012 L-DEO seismic 
surveys off southern Washington, northeast of the planned survey area 
(RPS 2012a). This species was not sighted during the July 2012 L-DEO 
seismic survey off Oregon, southeast of the planned survey area (RPS 
2012c). Dall's porpoise was the most frequently sighted marine mammal 
species (5 sightings of 28 animals) during the 2009 ETOMO survey north 
of the planned survey area (Holst 2017).
Northern Fur Seal
    The Navy estimated the abundance of northern fur seals from the 
Eastern Pacific stock and the California breeding stock that could 
occur in the NWTT Offshore Study Area by determining the percentage of 
time tagged animals spent within the Study Area and applying that 
percentage to the population to calculate an abundance for adult 
females, juveniles, and pups independently on a monthly basis. Adult 
males are not expected to occur within the Offshore Study Area and the 
planned survey area during the planned geophysical survey as they spend 
the summer ashore at breeding areas in the Bering Sea and San Miguel 
Island (Caretta et al., 2017b). Using the monthly abundances of fur 
seals within the Offshore Study Area, the Navy created strata to 
estimate the density of fur seals within three strata: 22 km to 70 km 
from shore, 70 km to 130 km from shore, and 130 km to 463 km from shore 
(the western Study Area boundary). L-DEO's planned survey is 423 km 
from shore at the closest point. Based on satellite tag data and 
historic sealing records (Olesiuk 2012; Kajimura 1984), the Navy 
assumed 25 percent of the population present within the overall 
Offshore Study Area may be within the 130 km to 463 km stratum.
    During the public comment period, the Commission noted that the 
Navy's density estimates for northern fur seals did not include 
abundance data collected from Bogoslof Island in 2015. Incorporating 
the 2015 Bogoslof counts yielded an increased abundance estimate, and 
thus an increased density of northern fur seals. The density estimate 
increased from 0.0103 animals/km\2\ to 0.01065 animals/km\2\. As a 
result, the estimated take of northern fur seals increased from 194 
takes by Level B harassment to 201. No Level A take of northern fur 
seals is anticipated nor authorized.
    Thirty-one northern fur seal sightings (63 animals) were made off 
Washington/Oregon during the June-July 2012 L-DEO Juan de Fuca plate 
seismic survey north of the planned survey area (RPS 2012b). There were 
six sightings (6 animals) made during the July 2012 L-DEO seismic 
surveys off southern Washington, northeast of the planned survey area 
(RPS 2012a). This species was not sighted during the July 2012 L-DEO 
seismic survey off Oregon, southeast of the planned survey area (RPS 
2012c).
Guadalupe Fur Seal
    As with northern fur seals, adult male Guadalupe fur seals are 
expected to be ashore at breeding areas over the summer, and are not 
expected to be present during the planned geophysical survey (Caretta 
et al., 2017b; Norris 2017b). Additionally, breeding females are 
unlikely to be present within the Offshore Study Area as they remain 
ashore to nurse their pups through the fall and winter, making only 
short foraging trips from rookeries (Gallo-Reynoso et al., 2008; Norris 
2017b; Yochem et al., 1987). To estimate the total abundance of 
Guadalupe fur seals, the Navy adjusted the population reported in the 
2016 SAR (Caretta et al., 2017b) of 20,000 seals by applying the 
average annual growth rate of 7.64 percent over the seven years between 
2010 and 2017. The resulting 2017 projected abundance was 33,485 fur 
seals. Using the reported composition of the breeding population of 
Guadalupe fur seals (Gallo-Reynoso 1994) and satellite telemetry data 
(Norris 2017b), the Navy established seasonal and demographic 
abundances of fur seals expected to occur within the Offshore Study 
Area.
    The distribution of Guadalupe fur seals in the Offshore Study Area 
was stratified by distance from shore (or water depth) to reflect their 
preferred pelagic habitat (Norris, 2017a). Ten percent of fur seals in 
the Study Area are expected to use waters over the continental shelf 
(approximated as waters with depths between 10 and 200 m). A depth of 
10 m is used as the shoreward extent of the shelf (rather than 
extending to shore), because Guadalupe fur seals in the Offshore Study 
Area are not expected to haul out and would not be likely to come close 
to shore. All fur seals (i.e., 100 percent) would use waters off the 
shelf (beyond the 200-m isobath) out to 300 km from shore, and 25 of 
percent of fur seals would be expected to use waters between 300 and 
700 km from shore (including the planned geophysical survey area). The 
second stratum (200 m to 300 km from shore) is the preferred habitat 
where Guadalupe fur seals are most likely to occur most of the time. 
Individuals may spend a portion of their time over the continental 
shelf or farther than 300 km from shore, necessitating a density 
estimate for those areas, but all Guadalupe fur seals would be expected 
to be in the central stratum most of the time, which is the reason 100 
percent is used in the density estimate for the central stratum 
(Norris, 2017a). Spatial areas for the three strata were estimated in a 
GIS and used to calculate the densities.
    During the public comment period, the Commission noted that the 
Navy density estimate for Guadalupe fur seals projected the abundance 
through 2017, while L-DEO's survey will occur in 2019. The Commission 
recommended calculating the abundance estimate in 2019 using the annual 
growth rate above. This calculation yielded an increased density 
estimate of Guadalupe fur seals, from 0.0029 animals/km\2\ to 0.00343 
animals/km\2\. As such, the take estimate increased from 55 takes by 
Level B harassment to 65. No Level A take of Guadalupe fur seals is 
anticipated or authorized.
    Guadalupe fur seals have not previously been observed in the 
planned survey area, nor on previous L-DEO surveys off Washington and 
Oregon.
Northern Elephant Seal
    The most recent surveys supporting the abundance estimate for 
northern elephant seals were conducted in 2010 (Caretta et al., 2017b). 
By applying the average growth rate of 3.8 percent per year for the 
California breeding stock over the seven years from 2010 to 2017, the 
Navy calculated a projected 2017 abundance estimate of 232,399 elephant 
seals (Caretta et al., 2017b; Lowry et al., 2014). Male and female 
distributions at sea differ both seasonally and spatially. Pup counts 
reported by Lowry et al., (2014) and life tables compiled by Condit et 
al., (2014) were used to determine the proportion of males and females 
in the population, which was

[[Page 35089]]

estimated to be 56 percent female and 44 percent male. Females are 
assumed to be at sea 100 percent of the time within their seasonal 
distribution area in fall and summer (Robinson et al., 2012). Males are 
at sea approximately 90 percent of the time in fall and spring, remain 
ashore through the entire winter, and spend one month ashore to molt in 
the summer (i.e., are at sea 66 percent of the summer). Monthly 
distribution maps produced by Robinson et al. (2012) showing the extent 
of foraging areas used by satellite tagged female elephant seals were 
used to estimate the spatial areas to calculate densities. Although the 
distributions were based on tagged female seals, Le Boeuf et al. (2000) 
and Simmons et al. (2007) reported similar tracks by males over broad 
spatial scales. The spatial areas representing each monthly 
distribution were calculating using GIS and then averaged to produce 
seasonally variable areas and resulting densities.
    Similar to the Guadalupe fur seal above, the Commission suggested 
using the population growth rate above to calculate the abundance of 
northern elephant seals in 2019. The resulting density estimate of 
northern elephant seals increased from 0.0309 animals/km\2\ to 0.03333 
animals/km\2\. As such, the estimated take by Level B harassment 
increased from 583 to 629 animals. Take of northern elephant seals by 
Level A harassment is not anticipated or authorized.
    Off Washington, most elephant seal sightings at sea were made 
during June, July, and September; off Oregon, sightings were recorded 
from November through May (Bonnell et al. 1992). Several seals were 
seen off Oregon during summer, fall, and winter surveys in 2011 and 
2012 (Adams et al. 2014). Northern elephant seals were also taken as 
bycatch off Oregon in the west coast groundfish fishery during 2002-
2009 (Jannot et al. 2011). Northern elephant seals were sighted five 
times (5 animals) during the July 2012 L-DEO seismic surveys off 
southern Washington, northeast of the planned survey area (RPS 2012a). 
This species was not sighted during the July 2012 L-DEO seismic survey 
off Oregon, southeast of the planned survey area (RPS 2012c), or off 
Washington/Oregon during the June-July 2012 L-DEO Juan de Fuca plate 
seismic survey that included the planned survey area (RPS 2012b). One 
northern elephant seal was sighted during the 2009 ETOMO survey north 
of the planned survey area (Holst 2017).

        Table 7--Marine Mammal Density Values in the Survey Area
------------------------------------------------------------------------
                                                             Reported
                         Species                            density (#/
                                                            km\2\) \a\
------------------------------------------------------------------------
LF Cetaceans:
    Humpback whale......................................        0.001829
    Minke whale.........................................          0.0013
    Sei whale...........................................          0.0004
    Fin whale...........................................        0.004249
    Blue whale..........................................        0.001096
MF Cetaceans:
    Sperm whale.........................................        0.002561
    Cuvier's and Mesoplodont beaked whales..............        0.007304
    Baird's beaked whale................................         0.00082
    Bottlenose dolphin..................................        0.000003
    Striped dolphin.....................................        0.009329
    Short-beaked common dolphin.........................        0.124891
    Pacific white-sided dolphin.........................        0.017426
    Northern right-whale dolphin........................        0.039962
    Risso's dolphin.....................................        0.007008
    False killer whale..................................             N/A
    Killer whale........................................     \b\ 0.00092
    Short-finned pilot whale............................         0.00025
HF Cetaceans:
    Kogia spp...........................................         0.00163
    Dall's porpoise.....................................        0.043951
Otariids:
    Northern fur seal...................................     b c 0.01065
    Guadalupe fur seal..................................     \c\ 0.00343
Phocids:
    Northern elephant seal..............................     \c\ 0.03333
------------------------------------------------------------------------
\a\ Navy 2018.
\b\ No stock-specific densities are available so densities are presumed
  equal for all stocks present.
\c\ Density estimate increased from that presented in Federal Register
  notice of proposed IHA (84 FR 26940; June 10, 2019).

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 
area estimated to be ensonified in a single day of the survey is then 
calculated (Table 8), based on the areas predicted to be ensonified 
around the array and representative trackline distances traveled per 
day. This number is then multiplied by the number of survey days. The 
product is then multiplied by 1.25 to account for the additional 25 
percent contingency. This results in an estimate of the total areas 
(km\2\) expected to be ensonified to the Level A and Level B harassment 
thresholds.

                         Table 8--Areas (km\2\) Estimated To Be Ensonified to Level A and Level B Harassment Thresholds, Per Day
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                               Daily                                           Total
                  Survey                              Criteria               Relevant       ensonified     Total survey    25% increase     ensonified
                                                                           isopleth  (m)   area  (km\2\)       days                        area (km\2\)
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                            Level B Harassment
                                           -------------------------------------------------------------------------------------------------------------
2-D Survey................................  160-dB......................           6,733        1,346.90               3            1.25        5,050.86
                                           -------------------------------------------------------------------------------------------------------------
                                            Level A Harassment
                                           -------------------------------------------------------------------------------------------------------------
                                            LF Cetaceans................           426.9          158.67               3            1.25          595.01
                                            HF Cetaceans................           268.3           99.77               3            1.25          374.12
                                            Phocids.....................            43.7           16.26               3            1.25           60.96
                                            MF Cetaceans................            13.6            5.06               3            1.25           18.97
                                            Otariids....................            10.6            3.94               3            1.25           14.79
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                            Level B Harassment
                                           -------------------------------------------------------------------------------------------------------------

[[Page 35090]]

 
3-D Survey................................  160-dB......................           3,758          690.52              16            1.25       13,810.40
                                           -------------------------------------------------------------------------------------------------------------
                                            Level A Harassment
                                           -------------------------------------------------------------------------------------------------------------
                                            LF Cetaceans................           118.7           47.39              16            1.25          947.74
                                            HF Cetaceans................            75.6           30.13              16            1.25          602.59
                                            Phocids.....................            25.1            9.98              16            1.25          199.59
                                            MF Cetaceans................            11.2            4.45              16            1.25           89.01
                                            Otariids....................             9.9            3.93              16            1.25           78.67
--------------------------------------------------------------------------------------------------------------------------------------------------------

    The marine mammals predicted to occur within these respective 
areas, based on estimated densities, are assumed to be incidentally 
taken. For species where take by Level A harassment has been requested, 
the calculated Level A takes have been subtracted from the total 
exposures within the Level B harassment zone. During the public comment 
period, the Commission noted that the typical group size for sei whales 
is two animals (Barlow 2016) and recommended increasing the Level A 
take to two animals and reducing the Level B takes to six animals. NMFS 
agreed and has made that change. Authorized takes for the planned 
survey are shown in Table 9.

                Table 9--Estimated Level A and Level B Exposures, and Percentage of Stock Exposed
----------------------------------------------------------------------------------------------------------------
                                                                                                    Percent  of
            Species                   Stock           Level B         Level A       Total take         stock
----------------------------------------------------------------------------------------------------------------
LF Cetaceans:
    Humpback whale............  California/                   32               3              35            1.21
                                 Oregon/
                                 Washington.
    Minke whale...............  California/                   23               2              25            3.93
                                 Oregon/
                                 Washington.
    Sei whale.................  Eastern North                  6               2               8            1.54
                                 Pacific.
    Fin whale.................  California/                   74               7              81            0.90
                                 Oregon/
                                 Washington.
    Blue whale................  Eastern North                 19               2              21            1.28
                                 Pacific.
MF Cetaceans:
    Sperm whale...............  California/                   48               0              48            2.40
                                 Oregon/
                                 Washington.
    Cuvier's and Mesoplodont    California/                  138               0             138        \a\ 2.18
     beaked whales.              Oregon/
                                 Washington.
    Baird's beaked whale......  California/                   15               0              15            0.56
                                 Oregon/
                                 Washington.
    Bottlenose dolphin........  California/               \b\ 13               0          \b\ 13            0.68
                                 Oregon/
                                 Washington.
    Striped dolphin...........  California/                  176               0             176            0.60
                                 Oregon/
                                 Washington.
    Short-beaked common         California/                 2356               0            2356            0.24
     dolphin.                    Oregon/
                                 Washington.
    Pacific white-sided         California/                  329               0             329            1.23
     dolphin.                    Oregon/
                                 Washington.
    Northern right-whale        California/                  754               0             754            2.82
     dolphin.                    Oregon/
                                 Washington.
    Risso's dolphin...........  California/                  132               0             132            2.08
                                 Oregon/
                                 Washington.
    False killer whale........  Hawaii Pelagic..           \b\ 5               0           \b\ 5            0.32
    Killer whale..............  Offshore........              17               0              17        \c\ 5.67
                                West Coast        ..............  ..............  ..............        \c\ 7.00
                                 Transient.
    Short-finned pilot whale..  California/               \b\ 18               0          \b\ 18            2.15
                                 Oregon/
                                 Washington.
HF Cetaceans:
    Kogia spp.................  California/                   29               2              31            0.71
                                 Oregon/
                                 Washington.
    Dall's porpoise...........  California/                  786              43             829            3.05
                                 Oregon/
                                 Washington.
Otariids:
    Northern fur seal.........  Eastern Pacific.             201               0             201        \c\ 0.03
                                California......  ..............  ..............  ..............        \c\ 1.43
    Guadalupe fur seal........  Mexico..........              65               0              65            0.33
Phocids:
    Northern elephant seal....  California                   629               0             629            0.35
                                 Breeding.
----------------------------------------------------------------------------------------------------------------
\a\ Combined stock abundances for Cuvier's beaked whales and Mesoplodont guild.
\b\ Calculated take increased to mean group size (Barlow 2016).
\c\ Where multiple stocks are affected, for the purposes of calculating the percentage of stock affected, takes
  are analyzed as if all takes occurred within each stock.

    It should be noted that the authorized take numbers shown in Table 
9 are expected to be conservative for several reasons. First, in the 
calculations of estimated take, 25 percent has been added in the form 
of operational survey days to account for the possibility of additional 
seismic operations associated with airgun testing and repeat coverage 
of any areas where initial data quality is sub-standard, and in 
recognition of the uncertainties in the density estimates used to 
estimate take as described above. Additionally, marine mammals would be 
expected to move away from

[[Page 35091]]

a loud sound source that represents an aversive stimulus, such as an 
airgun array, potentially reducing the number of takes by Level A 
harassment. However, the extent to which marine mammals would move away 
from the sound source is difficult to quantify and is, therefore, not 
accounted for in the take estimates.
    Note that due to the different density estimates used, and in 
consideration of the near-field soundscape of the airgun array, we have 
authorized a different number of incidental takes than the number of 
incidental takes requested by L-DEO (see Table 6 in the IHA 
application).

Mitigation

    In order to issue an IHA under Section 101(a)(5)(D) of the MMPA, 
NMFS must set forth the permissible methods of taking pursuant to such 
activity, and other means of effecting the least practicable impact on 
such species or stock and its habitat, paying particular attention to 
rookeries, mating grounds, and areas of similar significance, and on 
the availability of such species or stock for taking for certain 
subsistence uses (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 such 
activity or other means of effecting the least practicable adverse 
impact upon the affected species or stocks and their habitat (50 CFR 
216.104(a)(11)).
    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.
    L-DEO has reviewed mitigation measures employed during seismic 
research surveys authorized by NMFS under previous incidental 
harassment authorizations, as well as recommended best practices in 
Richardson et al. (1995), Pierson et al. (1998), Weir and Dolman 
(2007), Nowacek et al. (2013), Wright (2014), and Wright and Cosentino 
(2015), and has incorporated a suite of required mitigation measures 
into their project description based on the above sources.
    To reduce the potential for disturbance from acoustic stimuli 
associated with the activities, L-DEO is required to implement 
mitigation measures for marine mammals. Mitigation measures that would 
be adopted during the planned surveys include (1) Vessel-based visual 
mitigation monitoring; (2) Vessel-based passive acoustic monitoring; 
(3) Establishment of an exclusion zone; (4) Power down procedures; (5) 
Shutdown procedures; (6) Ramp-up procedures; and (7) Vessel strike 
avoidance measures.

Vessel-Based Visual Mitigation Monitoring

    Visual monitoring requires the use of trained observers (herein 
referred to as visual PSOs) to scan the ocean surface visually for the 
presence of marine mammals. The area to be scanned visually includes 
primarily the exclusion zone, but also the buffer zone. The buffer zone 
means an area beyond the exclusion zone to be monitored for the 
presence of marine mammals that may enter the exclusion zone. During 
pre-clearance monitoring (i.e., before ramp-up begins), the buffer zone 
also acts as an extension of the exclusion zone 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 
exclusion zone, out to a radius of 1,000 m from the edges of the airgun 
array (500-1,000 m). Visual monitoring of the exclusion zones 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 close to the vessel. Visual monitoring of the buffer 
zone is intended to (1) provide additional protection to na[iuml]ve 
marine mammals that may be in the area during pre-clearance, and (2) 
during airgun use, aid in establishing and maintaining the exclusion 
zone by alerting the visual observer and crew of marine mammals that 
are outside of, but may approach and enter, the exclusion zone.
    L-DEO must use at least five dedicated, trained, NMFS-approved 
Protected Species Observers (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 aboard the 
vessel must have a minimum of 90 days at-sea experience working in 
those roles, respectively, during a deep penetration (i.e., ``high 
energy'') seismic survey, 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) and 30 minutes prior to and during 
nighttime ramp-ups of the airgun array. Visual monitoring of the 
exclusion and buffer zones must begin no less than 30 minutes prior to 
ramp-up and must continue until one hour after use of the acoustic 
source ceases or until 30 minutes past sunset. Visual PSOs shall 
coordinate to ensure 360[deg] visual coverage around the vessel from 
the most appropriate observation posts, and shall conduct visual 
observations using binoculars and the naked eye while free from 
distractions and in a consistent, systematic, and diligent manner.
    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

[[Page 35092]]

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

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 exclusion zone 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.
    Passive acoustic monitoring (PAM) would 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. Acoustical monitoring can be used 
in addition to visual observations to improve detection, 
identification, and localization of cetaceans. The acoustic monitoring 
would serve to alert visual PSOs (if on duty) when vocalizing cetaceans 
are detected. It is only useful when marine mammals call, but it can be 
effective either by day or by night, and does not depend on good 
visibility. It would 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 four consecutive 
hours followed by a break of at least one hour between watches and may 
conduct a maximum of 12 hours of observation per 24-hour period. 
Combined observational duties (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 two 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 the applicable exclusion zone in the previous two 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 four hours in 
any 24-hour period.

Establishment of Exclusion and Buffer Zones

    An exclusion zone (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 would establish a minimum EZ with a 500-m 
radius. The 500-m EZ would be based on radial distance from any element 
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 would be shut down.
    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 SPL), while also providing a consistent, 
reasonably observable zone within which PSOs would 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.
    An extended EZ of 1,500 m must be enforced for all beaked whales, 
and dwarf and pygmy sperm whales.

Pre-Clearance and Ramp-Up

    Ramp-up (sometimes referred to as ``soft start'') means the gradual 
and systematic increase of emitted sound levels from an airgun array. 
Ramp-up begins by first activating a single airgun of the smallest 
volume, followed by doubling the number of active elements in stages 
until the full complement of an array's airguns are active. Each stage 
should be approximately the same duration, and the total duration 
should not be less than approximately 20 minutes. The intent of pre-
clearance observation (30 minutes) is to ensure no protected species 
are observed within the buffer zone prior to the beginning of ramp-up. 
During pre-clearance is the only time observations of protected species 
in the buffer zone would prevent operations (i.e., the beginning of 
ramp-up). The intent of ramp-up is to warn protected species of pending 
seismic operations and to allow sufficient time for those animals to 
leave the immediate vicinity. A ramp-up procedure, involving a step-
wise increase in the number of airguns firing and total array volume 
until all operational airguns are activated and the full volume is 
achieved, is required at all times as part of the activation of

[[Page 35093]]

the acoustic source. All operators must adhere to the following pre-
clearance and ramp-up requirements:
     The operator must notify a designated PSO of the planned 
start of ramp-up as agreed upon with the lead PSO; the notification 
time should not be less than 60 minutes prior to the planned ramp-up in 
order to allow the PSOs time to monitor the exclusion and buffer zones 
for 30 minutes prior to the initiation of ramp-up (pre-clearance);
     Ramp-ups shall be scheduled so as to minimize the time 
spent with the source activated prior to reaching the designated run-
in;
     One of the PSOs conducting pre-clearance observations must 
be notified again immediately prior to initiating ramp-up procedures 
and the operator must receive confirmation from the PSO to proceed;
     Ramp-up may not be initiated if any marine mammal is 
within the applicable exclusion or buffer zone. If a marine mammal is 
observed within the applicable exclusion zone or the buffer zone during 
the 30 minute pre-clearance period, ramp-up may not begin until the 
animal(s) has been observed exiting the zones or until an additional 
time period has elapsed with no further sightings (15 minutes for small 
odontocetes and pinnipeds, and 30 minutes for all mysticetes and all 
other odontocetes, including sperm whales, pygmy sperm whales, dwarf 
sperm whales, beaked whales, pilot whales, and Risso's dolphins);
     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 exclusion and buffer zones during 
ramp-up, and ramp-up must cease and the source must be shut down upon 
observation of a marine mammal within the applicable exclusion zone. 
Once ramp-up has begun, observations of marine mammals within the 
buffer zone do not require shutdown or powerdown, but such observation 
shall be communicated to the operator to prepare for the potential 
shutdown or powerdown;
     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 and powerdown (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 exclusion zone. For 
any longer shutdown, pre-clearance observation and ramp-up are 
required. For any shutdown at night or in periods of poor visibility 
(e.g., BSS 4 or greater), ramp-up is required, but if the shutdown 
period was brief and constant observation was maintained, pre-clearance 
watch of 30 min is not required; and
     Testing of the acoustic source involving all elements 
requires ramp-up. Testing limited to individual source elements or 
strings does not require ramp-up but does require pre-clearance of 30 
min.

Shutdown and Powerdown

    The shutdown of an airgun array requires the immediate de-
activation of all individual airgun elements of the array while a 
powerdown requires immediate de-activation of all individual airgun 
elements of the array except the single 40-in\3\ airgun. Any PSO on 
duty will have the authority to delay the start of survey operations or 
to call for shutdown or powerdown of the acoustic source if a marine 
mammal is detected within the applicable exclusion zone. The operator 
must also establish and maintain clear lines of communication directly 
between PSOs on duty and crew controlling the acoustic source to ensure 
that shutdown and powerdown 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 powerdown) and (1) a 
marine mammal appears within or enters the applicable exclusion zone 
and/or (2) a marine mammal (other than delphinids, see below) is 
detected acoustically and localized within the applicable exclusion 
zone, 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 would not resume until the 
marine mammal has cleared the 500-m EZ. The animal would be considered 
to have cleared the 500-m EZ if it is visually observed to have 
departed the 500-m EZ, or it has not been seen within the 500-m EZ for 
15 min in the case of small odontocetes and pinnipeds, or 30 min in the 
case of mysticetes and large odontocetes, including sperm whales, pygmy 
sperm whales, dwarf sperm whales, pilot whales, beaked whales, and 
Risso's dolphins.
    The shutdown requirement can be waived for small dolphins in which 
case the acoustic source shall be powered down to the single 40-in\3\ 
airgun if an individual is visually detected within the exclusion zone. 
As defined here, the small delphinoid 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--
Tursiops, Delphinus, Stenella, Lagenorhynchus, and Lissodelphis. The 
acoustic source must be powered down to 40-in\3\ airgun if an 
individual belonging to these genera is visually detected within the 
500-m exclusion zone.
    Powerdown conditions shall be maintained until delphinids for which 
shutdown is waived are no longer observed within the 500-m exclusion 
zone, following which full-power operations may be resumed without 
ramp-up. Visual PSOs may elect to waive the powerdown requirement if 
delphinids for which shutdown is waived to be voluntarily approaching 
the vessel for the purpose of interacting with the vessel or towed 
gear, and may use best professional judgment in making this decision.
    We include this small delphinoid exception because power-down/
shutdown requirements for small delphinoids under all circumstances 
represent practicability concerns without likely commensurate benefits 
for the animals in question. Small delphinoids are generally the most 
commonly observed marine mammals in the specific geographic region and 
would typically be the only marine

[[Page 35094]]

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 delphinoids 
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). 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 delphinoids) are no more likely to incur 
auditory injury than are small delphinoids, they are much less likely 
to approach vessels. Therefore, retaining a power-down/shutdown 
requirement for large delphinoids 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 power-down/shutdown requirement for large delphinoids 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.
    Powerdown conditions shall be maintained until the marine mammal(s) 
of the above listed genera are no longer observed within the exclusion 
zone, following which full-power operations may be resumed without 
ramp-up. Additionally, visual PSOs may elect to waive the powerdown 
requirement if the small dolphin(s) appear to be voluntarily 
approaching the vessel for the purpose of interacting with the vessel 
or towed gear, and may use best professional judgment in making this 
decision. 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 exclusion zone). If PSOs observe any behaviors in 
a small delphinid for which shutdown is waived that indicate an adverse 
reaction, then powerdown will be initiated immediately.
    Upon implementation of shutdown, the source may be reactivated 
after the marine mammal(s) has been observed exiting the applicable 
exclusion zone (i.e., animal is not required to fully exit the buffer 
zone where applicable) or following 15 minutes for small odontocetes 
and pinnipeds, and 30 minutes for mysticetes and all other odontocetes, 
including sperm whales, pygmy sperm whales, dwarf sperm whales, beaked 
whales, pilot whales, and Risso's dolphins, with no further observation 
of the marine mammal(s).
    The following shutdown requirements have been added to the final 
IHA as they were not included in the proposed IHA:
     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 implement shutdown if 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) or an aggregation of six or more large 
whales is observed at any distance; and
     L-DEO must implement shutdown if a North Pacific right 
whale is observed at any distance.

Vessel Strike Avoidance

    These measures apply to all vessels associated with the planned 
survey activity; however, we note that 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. These measures include the following:
    1. Vessel operators and crews must maintain a vigilant watch for 
all marine mammals and slow down, stop their vessel, or alter course, 
as appropriate and regardless of vessel size, to avoid striking any 
marine mammal. A single marine mammal at the surface may indicate the 
presence of submerged animals in the vicinity of the vessel; therefore, 
precautionary measures should be exercised when an animal is observed. 
A visual observer aboard the vessel must monitor a vessel strike 
avoidance zone around the vessel (specific distances detailed below), 
to ensure the potential for strike is minimized. Visual observers 
monitoring the vessel strike avoidance zone can be either third-party 
observers or crew members, but crew members responsible for these 
duties must be provided sufficient training to distinguish marine 
mammals from other phenomena and broadly to identify a marine mammal to 
broad taxonomic group (i.e., as a large whale or other marine mammal);
    2. Vessel speeds must be reduced to 10 kn or less when mother/calf 
pairs, pods, or large assemblages of any marine mammal are observed 
near a vessel;
    3. All vessels must maintain a minimum separation distance of 100 m 
from large whales (i.e., sperm whales and all baleen whales);
    4. All vessels must attempt to maintain a minimum separation 
distance of 50 m from all other marine mammals, with an exception made 
for those animals that approach the vessel; and
    5. When marine mammals are sighted while a vessel is underway, the 
vessel should 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 should reduce speed and shift 
the engine to neutral, not engaging the engines until animals are clear 
of the area. This recommendation does not apply to any vessel towing 
gear.
    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, NMFS has determined that the mitigation measures provide the 
means effecting the least practicable impact on the affected species or 
stocks and their habitat, paying particular attention to rookeries, 
mating grounds, and areas of similar significance.

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

[[Page 35095]]

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 would take place during 
daytime airgun operations and nighttime start ups (if applicable) of 
the airguns. During seismic operations, at least five visual PSOs would 
be based aboard the Langseth. 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;
     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 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

[[Page 35096]]

     Survey activity information, such as acoustic source power 
output while in operation, number and volume of airguns operating in 
the array, tow depth of the array, and any other notes of significance 
(i.e., pre-clearance, ramp-up, shutdown, testing, shooting, ramp-up 
completion, end of operations, streamers, etc.).
    The following information should be recorded upon visual 
observation of any protected species:
     Watch status (sighting made by PSO on/off effort, 
opportunistic, crew, alternate vessel/platform);
     PSO who sighted the animal;
     Time of sighting;
     Vessel location at time of sighting;
     Water depth;
     Direction of vessel's travel (compass direction);
     Direction of animal's travel relative to the vessel;
     Pace of the animal;
     Estimated distance to the animal and its heading relative 
to vessel at initial sighting;
     Identification of the animal (e.g., genus/species, lowest 
possible taxonomic level, or unidentified) and the composition of the 
group if there is a mix of species;
     Estimated number of animals (high/low/best);
     Estimated number of animals by cohort (adults, yearlings, 
juveniles, calves, group composition, etc.);
     Description (as many distinguishing features as possible 
of each individual seen, including length, shape, color, pattern, scars 
or markings, shape and size of dorsal fin, shape of head, and blow 
characteristics);
     Detailed behavior observations (e.g., number of blows/
breaths, number of surfaces, breaching, spyhopping, diving, feeding, 
traveling; as explicit and detailed as possible; note any observed 
changes in behavior);
     Animal's closest point of approach (CPA) and/or closest 
distance from any element of the acoustic source;
     Platform activity at time of sighting (e.g., deploying, 
recovering, testing, shooting, data acquisition, other); and
     Description of any actions implemented in response to the 
sighting (e.g., delays, shutdown, ramp-up) and time and location of the 
action.
    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 would be submitted to NMFS within 90 days after the end of 
the cruise. The report would describe the operations that were 
conducted and sightings of marine mammals near the operations. The 
report would provide full documentation of methods, results, and 
interpretation pertaining to all monitoring. The 90-day report would 
summarize the dates and locations of seismic operations, and all marine 
mammal sightings (dates, times, locations, activities, associated 
seismic survey activities). The report would also include estimates of 
the number and nature of exposures that occurred above the harassment 
threshold based on PSO observations and including an estimate of those 
that were not detected, in consideration of both the characteristics 
and behaviors of the species of marine mammals that affect 
detectability, as well as the environmental factors that affect 
detectability.
    L-DEO is required to submit a draft comprehensive report to NMFS on 
all activities and monitoring results within 90 days of the completion 
of the survey or expiration of the IHA, whichever comes sooner. The 
report must describe all activities conducted and sightings of 
protected species near the activities, must provide full documentation 
of methods, results, and interpretation pertaining to all monitoring, 
and must summarize the dates and locations of survey operations and all 
protected species sightings (dates, times, locations, activities, 
associated survey activities). The draft report shall also include geo-
referenced time-stamped vessel tracklines for all time periods during 
which airguns were operating. Tracklines should include points 
recording any change in airgun status (e.g., when the airguns began 
operating, when they were turned off, or when they changed from full 
array to single gun or vice versa). GIS files shall be provided in ESRI 
shapefile format and include the UTC date and time, latitude in decimal 
degrees, and longitude in decimal degrees. All coordinates shall be 
referenced to the WGS84 geographic coordinate system. In addition to 
the report, all raw observational data shall be made available to NMFS. 
The report must summarize the information submitted in interim monthly 
reports as well as additional data collected as described above and the 
IHA. The draft report must be accompanied by a certification from the 
lead PSO as to the accuracy of the report, and the lead PSO may submit 
directly NMFS a statement concerning implementation and effectiveness 
of the required mitigation and monitoring. A final report must be 
submitted within 30 days following resolution of any comments on the 
draft report.

Reporting 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 West Coast Regional Stranding Coordinator 
as soon as feasible. The report must include the following information:
     Time, date, and location (latitude/longitude) of the first 
discovery (and updated location information if known and applicable);
     Species identification (if known) or description of the 
animal(s) involved;
     Condition of the animal(s) (including carcass condition if 
the animal is dead);
     Observed behaviors of the animal(s), if alive;
     If available, photographs or video footage of the 
animal(s); and
     General circumstances under which the animal was 
discovered.
    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 (example circumstances noted below), and an 
investigation into the stranding is being pursued, NMFS will submit a 
written request to the IHA-holder 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.
    Examples of circumstances that could trigger the additional 
information

[[Page 35097]]

request include, but are not limited to, the following:
     Atypical nearshore milling events of live cetaceans;
     Mass strandings of cetaceans (two or more individuals, not 
including cow/calf pairs);
     Beaked whale strandings;
     Necropsies with findings of pathologies that are unusual 
for the species or area; or
     Stranded animals with findings consistent with blast 
trauma.
    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.
    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 must shall report the incident to OPR, NMFS and to regional 
stranding coordinators as soon as feasible. The report must include the 
following information:
     Time, date, and location (latitude/longitude) of the 
incident;
     Species identification (if known) or description of the 
animal(s) involved;
     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 measures 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;
     Estimated size and length of animal that was struck;
     Description of the behavior of the marine mammal 
immediately preceding and following the strike;
     If available, description of the presence and behavior of 
any other marine mammals immediately preceding the strike;
     Estimated fate of the animal (e.g., dead, injured but 
alive, injured and moving, blood or tissue observed in the water, 
status unknown, disappeared); and
     To the extent practicable, photographs or video footage of 
the animal(s).

Negligible Impact Analysis and Determination

    NMFS has defined negligible impact as an impact resulting from the 
specified activity that cannot be reasonably expected to, and is not 
reasonably likely to, adversely affect the species or stock through 
effects on annual rates of recruitment or survival (50 CFR 216.103). A 
negligible impact finding is based on the lack of likely adverse 
effects on annual rates of recruitment or survival (i.e., population-
level effects). An estimate of the number of takes alone is not enough 
information on which to base an impact determination. In addition to 
considering estimates of the number of marine mammals that might be 
``taken'' through harassment, NMFS considers other factors, such as the 
likely nature of any responses (e.g., intensity, duration), the context 
of any responses (e.g., critical reproductive time or location, 
migration), as well as effects on habitat, and the likely effectiveness 
of the mitigation. We also assess the number, intensity, and context of 
estimated takes by evaluating this information relative to population 
status. Consistent with the 1989 preamble for NMFS's implementing 
regulations (54 FR 40338; September 29, 1989), the impacts from other 
past and ongoing anthropogenic activities are incorporated into this 
analysis via their impacts on the environmental baseline (e.g., as 
reflected in the regulatory status of the species, population size and 
growth rate where known, ongoing sources of human-caused mortality, or 
ambient noise levels).
    To avoid repetition, our analysis applies to all species listed in 
Tables 7 and 9, given that NMFS expects the anticipated effects of the 
planned geophysical survey to be similar in nature. Where there are 
meaningful differences between species or stocks, or groups of species, 
in anticipated individual responses to activities, impact of expected 
take on the population due to differences in population status, or 
impacts on habitat, NMFS has identified species-specific factors to 
inform the analysis.
    NMFS does not anticipate that serious injury or mortality would 
occur as a result of L-DEO's planned survey, even in the absence of 
mitigation. Thus the authorization does not authorize any mortality. As 
discussed in the Potential Effects section, non-auditory physical 
effects, stranding, and vessel strike are not expected to occur.
    We have authorized a limited number of instances of Level A 
harassment of seven species and Level B harassment of 26 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, and would be unlikely to affect the 
fitness of any individuals, because of the constant movement of both 
the 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 (i.e., since the duration of exposure to loud 
sounds will be relatively short). Also, as described above, we expect 
that marine mammals would be likely to 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 Langseth's 
approach due to the vessel's relatively low speed when conducting 
seismic surveys. We expect that the majority of takes would be in the 
form of short-term Level B behavioral harassment in the form of 
temporary avoidance of the area or decreased foraging (if such activity 
were occurring), reactions that are considered to be of low severity 
and with no lasting biological consequences (e.g., Southall et al., 
2007).
    Potential impacts to marine mammal habitat were discussed 
previously in this document (see Potential Effects of the Specified 
Activity on Marine Mammals and their Habitat). Marine mammal habitat 
may be impacted by elevated sound levels, but these impacts would be 
temporary. Prey species are mobile and are broadly distributed 
throughout the project 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 
(~19 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 activity is expected to impact a small percentage of all marine 
mammal stocks that would be affected by L-DEO's planned survey (less 
than seven percent of all species). Additionally, the acoustic 
``footprint'' of the planned survey would be small relative to the 
ranges of the marine mammals that would potentially be affected. Sound 
levels would increase in the marine

[[Page 35098]]

environment in a relatively small area surrounding the vessel compared 
to the range of the marine mammals within the planned survey area. The 
planned geophysical survey occurs outside of the U.S. EEZ and outside 
of any established Biologically Important Areas or critical habitat.
    The required 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 power downs and/
or shutdowns of the airgun array. Based on previous monitoring reports 
for substantially similar activities that have been previously 
authorized by NMFS, we expect that the required mitigation will be 
effective in preventing at least some extent of potential PTS in marine 
mammals that may otherwise occur in the absence of the required 
mitigation.
    The ESA-listed marine mammal species under our jurisdiction that 
are likely to be taken by the planned surveys include the endangered 
sei, fin, blue, sperm, and Central America DPS humpback whales, and the 
threatened Mexico DPS humpback whale and Guadalupe fur seal. We have 
authorized very small numbers of takes for these species relative to 
their population sizes. Given the low probability of fitness impacts to 
any individual, combined with the small portion of any of these stocks 
impacted, we do not expect population-level impacts to any of these 
species. The other marine mammal species that may be taken by 
harassment during the planned surveys are not listed as threatened or 
endangered under the ESA. With the exception of the northern fur seal, 
none of the non-listed marine mammals for which we propose to authorize 
take are considered ``depleted'' or ``strategic'' by NMFS under the 
MMPA.
    NMFS concludes that exposures to marine mammal species and stocks 
due to L-DEO's planned survey would result in only short-term 
(temporary and short in duration) effects to individuals exposed. 
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 mortality is anticipated or authorized;
     The planned activity is temporary and of relatively short 
duration (19 days);
     The anticipated impacts of the planned 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 PTS that may occur are expected 
to be very small in number. Instances of PTS that are incurred in 
marine mammals would 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 planned 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 planned 
survey would be temporary and spatially limited; and
     The required mitigation measures, including visual and 
acoustic monitoring, power-downs, and shutdowns, are expected to 
minimize potential impacts to marine mammals.
    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 monitoring and 
mitigation measures, NMFS finds that the total marine mammal take from 
the planned 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. Additionally, other qualitative 
factors may be considered in the analysis, such as the temporal or 
spatial scale of the activities.
    Table 9 provides the authorized numbers of take by Level A and 
Level B harassment, which are used here for purposes of the small 
numbers analysis. The numbers of marine mammals that we have authorized 
to be taken by Level A and Level B harassment would be considered small 
relative to the relevant populations (less than seven percent for all 
species and stocks) for the species for which abundance estimates are 
available.
    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

    There are no relevant subsistence uses of the affected marine 
mammal stocks or species implicated by this action. 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 
NSF prepared an Environmental Analysis (EA) to consider the direct, 
indirect, and cumulative effects to the human environment from this 
marine geophysical survey in the Northeast Pacific. 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-
6, NMFS has review the NSF's EA, determined it to be sufficient, and 
adopted that EA and signed a Finding of No Significant Impact (FONSI) 
on July 10, 2019.

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

[[Page 35099]]

designated critical habitat. To ensure ESA compliance for the issuance 
of IHAs, NMFS consults internally, in this case with the ESA 
Interagency Cooperation Division whenever we propose to authorize take 
for endangered or threatened species.
    The NMFS Office of Protected Resources Interagency Cooperation 
Division issued a Biological Opinion on July 10, 2019, 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 Permits and Conservation Division. 
The Biological Opinion concluded that the proposed action is not likely 
to jeopardize the continued existence of sei whale, fin whale, blue 
whale, sperm whale, humpback whale (Central America DPS and Mexico 
DPS), and Guadalupe fur seal, and is not likely to destroy or modify 
critical habitat of listed species because no critical habitat exists 
for these species in the action area.

Authorization

    NMFS has issued an IHA to L-DEO for the potential harassment of 
small numbers of 26 marine mammal species incidental to a marine 
geophysical survey in the Northeast Pacific, provided the previously 
mentioned mitigation, monitoring, and reporting are incorporated.

    Dated: July 17, 2019.
Donna S. Wieting,
Director, Office of Protected Resources, National Marine Fisheries 
Service.
[FR Doc. 2019-15516 Filed 7-19-19; 8:45 am]
BILLING CODE 3510-22-P