Takes of Marine Mammals Incidental to Specified Activities; Taking Marine Mammals Incidental to a Marine Geophysical Survey in the Gulf of Alaska, 27246-27270 [2019-12319]

Agencies

• DEPARTMENT OF COMMERCE
• National Oceanic and Atmospheric Administration

[Federal Register Volume 84, Number 113 (Wednesday, June 12, 2019)]
[Notices]
[Pages 27246-27270]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2019-12319]


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DEPARTMENT OF COMMERCE

National Oceanic and Atmospheric Administration

RIN 0648-XG736


Takes of Marine Mammals Incidental to Specified Activities; 
Taking Marine Mammals Incidental to a Marine Geophysical Survey in the 
Gulf of Alaska

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 of Columbia University (L-DEO) to 
incidentally harass, by Level A and Level B harassment, marine mammals 
during seismic airgun activities associated with a marine geophysical 
survey in the Gulf of Alaska.

DATES: This Authorization is effective from June 1, 2019 through May 
31, 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/national/marine-mammal-protection/incidental-take-authorizations-research-and-other-activities. In case of problems 
accessing these documents, please call the contact listed above.

SUPPLEMENTARY INFORMATION:

Background

    The MMPA prohibits the ``take'' of marine mammals, with certain 
exceptions. Sections 101(a)(5)(A) and (D) of the MMPA (16 U.S.C. 1361 
et seq.) direct the Secretary of Commerce (as delegated to NMFS) to 
allow, upon request, the incidental, but not intentional, taking of 
small numbers of marine mammals by U.S. citizens who engage in a 
specified activity (other than commercial fishing) within a specified 
geographical region if certain findings are made and either regulations 
are issued or, if the taking is limited to harassment, a notice of a 
proposed incidental take authorization may be provided to the public 
for review.
    Authorization for incidental takings shall be granted if NMFS finds 
that the 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.
    The definitions of all applicable MMPA statutory terms cited above 
are included in the relevant sections below.

Summary of Request

    On November 20, 2018, NMFS received a request from L-DEO for an IHA 
to take marine mammals incidental to conducting seismic geophysical 
surveys in the Gulf of Alaska along the Alaska Peninsula subduction 
zone. On December 19, 2018, NMFS received a revised copy of the 
application, and that application was deemed adequate and complete on 
February 11, 2019. L-DEO's request is for take of a small number of 21 
marine mammal species by Level B harassment and Level A harassment. 
Underwater sound associated with airgun use may result in the 
behavioral harassment or auditory injury of marine mammals in the 
ensonified areas. Neither L-DEO nor NMFS expects serious injury or 
mortality to result from this activity and, therefore, an IHA is 
appropriate.
    NMFS previously issued an IHA to L-DEO for similar work (76 FR 
38621; July 1, 2011). L-DEO complied with all the requirements (e.g., 
mitigation, monitoring, and reporting) of the previous IHA and 
information regarding their monitoring results may be found in the 
``Description of Marine Mammals in the Area of Specified Activities.''

Description of the Specified Activity

Overview

    The specified activity consists of a high energy geophysical 
seismic survey conducted in a portion of the Gulf of Alaska. 
Researchers from Lamont-Doherty Earth Observatory (L-DEO and other 
institutions, with funding from NSF, plan to conduct the seismic survey 
from the Research Vessel (R/V) Marcus G. Langseth (Langseth) in the 
Gulf of Alaska during 2019. The NSF-owned Langseth is operated by 
Columbia University's L-DEO under an existing Cooperative Agreement. 
The planned seismic survey would likely occur in the Gulf of Alaska off 
the Alaska Peninsula and the eastern Aleutian islands during late 
spring 2019 and would use a 36-airgun towed array with a total 
discharge volume of ~6600 in \3\. The survey would take place within 
the U.S. Exclusive Economic Zone (EEZ), in water ~15 to ~6184 m deep 
and would take advantage of a network of ocean bottom seismometers 
(OBSs) and onshore seismometers currently installed in the area. During 
the survey, approximately 13 percent of the survey kilometers would 
take place in shallow water (<100 meter (m)), 27 percent would occur in 
intermediate water

[[Page 27247]]

depths (100-1000 m), and the rest (60 percent) would occur in deep 
water (>1000 m).
    The survey is expected to consist of up to 18 days of seismic 
operations and ~1 day of transit and survey approximate 4400 km of 
transect lines. The Langseth would leave from and return to port in 
Kodiak, likely during late spring (end of May/early June) 2019. 
Tentative sail dates are 1-19 June 2019.
    The main goal of L-DEO's planned seismic program is to conduct a 2D 
survey along the Alaska Peninsula subduction zone using airguns. The 
addition of active sources (airguns) to the existing seismic monitoring 
equipment in place would directly contribute to the overall project 
goals of imaging the architecture for the subduction zone and 
understanding the structures controlling how and where the planet's 
largest earthquakes occur.
    A detailed description of the planned geophysical survey is 
provided in the Federal Register notice for the proposed IHA (84 FR 
14200; April 9, 2019). Since that time, no changes have been made to 
the planned geophysical 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 April 9, 2019 (84 FR 14200). 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) and the public.
    Comment: The Commission recommended that NMFS refrain from issuing 
this authorization until L-DEO provides information on its efforts to 
contact Native Alaska communities and entities, and addresses any 
concerns that these groups raise.
    Response: NMFS provides a full description of these outreach 
efforts in this document (in the ``Effects of Specified Activities on 
Subsistence Uses of Marine Mammals'' section), as they are described by 
L-DEO in its final EA.
    Comment: The Commission recommended that NMFS adjust the density 
estimates used to estimate the numbers of potential takes by 
incorporating some measure of uncertainty. Since many of the references 
from which the density data originated include coefficients of 
variation (CVs), standard errors (SEs), or confidence intervals (CI), 
which provide information on uncertainty relative to the underlying 
data, the Commission recommended that NMFS adjust the density estimates 
using some measure of uncertainty (i.e., CV, SD, SE, upper CI) for the 
Gulf of Alaska survey area. The Commission believes that the 25 percent 
contingency increase, routinely included by L-DEO does not account for 
uncertainty in density, because it has been included prior to the 
raising of these concerns. The Commission also recommended that NMFS 
convene a working group of scientists to determine how best to 
incorporate uncertainty in density data that are extrapolated.
    Response: The Commission recommended that NMFS adjust density 
estimates using some measure of uncertainty. While we acknowledge the 
uncertainty in these (or any) density estimates, the take estimate 
methodology used here produces the most appropriate estimate of likely 
takes. Uniformly adjusting the density upward based on uncertainty in 
every situation will result in over-estimates of take (and an 
unrealistic associated analysis) and, in fact, marine mammal 
observations both during the activities conducted under the previous 
GOA IHA as well as other NSF surveys in no way suggest that the surveys 
are resulting in unauthorized numbers of take. Further, the 25 percent 
correction factor does help to conservatively account for uncertainties 
in the density data that were available for use in the take estimates. 
NMFS is open to consideration of specific correction factors for use 
for specific circumstances or species in future IHAs and looks forward 
to further discussion with the Commission on how best to incorporate 
uncertainty in density estimates in instances where density data is 
limited.
    Regarding the Commission's recommendation that NMFS convene an 
internal working group to determine what data sources are considered 
best available for the various species and in the various areas, NMFS 
may consider future action to address these issues, but currently 
intends to address these questions through ongoing interactions with 
the U.S. Navy, academic institutions, and other research organizations.
    Comment: The Commission recommended that NMFS increase its proposed 
Steller sea lion density based on the Department of the Navy's (2018) 
recently reported higher density estimates for Southeast Alaska and the 
Pacific Northwest.
    Response: Through discussions with the Commission, NMFS has 
increased the expected density of Steller sea lions to 0.0392 
individuals/km\2\ for inshore environments. This value is the higher, 
uncorrected, value determined by the Department of the Navy for the 
Gulf of Alaska. Further detail regarding this density change is 
included later in this document. NMFS believes, that while this density 
value may be older than those recommended by the Commission, it is the 
most spatially appropriate estimate available, and conservative.
    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 41 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 sound 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 14200; April 9, 2019) describe the applicant's 
approach to modeling Level A and Level B harassment zones. The model 
LDEO 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, LDEO 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, LDEO 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, LDEO modeled

[[Page 27248]]

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). LDEO used the deep-water radii obtained from model 
results down to a maximum water depth of 2,000 m (Figure 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 Marcus 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 LDEO's modeled 180 dB and 160 dB zones were approximately 28 
percent and 33 percent larger, respectively, than the in-situ, site-
specific measurements, thus confirming that LDEO's model was 
conservative in that case.
    The following is a summary of two additional analyses of in-situ 
data that support LDEO's use of the modeled Level A and Level B 
harassment zones in this particular case. In 2010, LDEO 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, LDEO 
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 Marcus 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 LDEO'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 LDEO'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 LDEO to address the issue of 
incorporating site-specific information for future authorizations for 
seismic surveys. However, LDEO'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 LDEO'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 LDEO'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 
provide specific guidance on model parameters nor prescribe 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 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 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 geophyscical and seismic surveys. The protocols are being 
developed on the basis of detailed review of available literature, 
including

[[Page 27249]]

peer-review 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 powerdowns are only allowed/required in lieu of shutdown 
when certain species of dolphins, specifically identified in the 
Mitigation section, 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 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 recommend 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. 
Additionally, the Commission recommends that if NMFS plans to use the 
renewal process frequently or for projects involving complex review, 
such as geophysical surveys, the comment period should be 30-days.
    Response: We believe our proposed method for issuing renewals meets 
statutory requirements and maximizes efficiency. Importantly, such 
renewals would be limited to circumstances where: The activities are 
identical or nearly identical to those analyzed in the proposed IHA; 
monitoring does not indicate impacts were incurred that were not 
previously analyzed and authorized; and, the mitigation and monitoring 
requirements remain the same, all of which allow the public to comment 
on the appropriateness and effects of a renewal at the same time the 
public provides comments on the initial IHA. As stated, if new 
monitoring information were to be available at the time a renewal was 
being considered, and NMFS determined that this information may 
indicate impacts not previously analyzed, the action would not meet the 
circumstances set forth for a renewal. Regarding the potential 
application of the Renewal process to this action, the case-by-case 
determination of whether or not a Renewal is appropriate would be made 
at the time L-DEO submits a request. If L-DEO submits a Renewal 
request, the Commission's recommendations will be considered at that 
time.
    Comment: One private citizen requested that we deny issuance of the 
IHA because marine mammals would be killed as a result of the survey.
    Response: This activity is not expected to result in the death of 
any marine mammal species, and no such take is authorized. Extensive 
analysis of the planned 2D seismic survey was conducted in accordance 
with the MMPA, Endangered Species Act (ESA), and National Environmental 
Policy Act (NEPA). We analyzed the impacts to marine mammals (including 
those listed as threatened or endangered under the ESA), to their 
habitat (including critical habitat designated under the ESA), and to 
the availability of marine mammals for taking for subsistence uses. The 
MMPA analyses revealed that the activities would have a negligible 
impact on affected marine mammal species or stocks and would not have 
an unmitigable adverse impact on the availability of marine mammals for 
taking for subsistence uses. The ESA analysis concluded that the 
activities are not likely to jeopardize the continued existence of ESA-
listed species or destroy or adversely modify designated critical 
habitat. The NEPA analysis, conducted by NSF and adopted by NMFS, 
concluded that there would not be a significant impact on the human 
environment.

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 (SAR; 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 Gulf of Alaska 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 (2017). 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.
    Sixteen species of cetaceans and five species of pinnipeds could 
occur in the planned Gulf of Alaska survey area. Cetacean species 
include seven species of mysticetes (baleen whales) and nine species of 
odontocetes (dolphins and small and large toothed whales).
    Ferguson et al. (2015) described Biological Important Areas (BIAs) 
for cetaceans in the Gulf of Alaska. BIAs were delineated for four 
baleen whale species and one toothed whale species including fin, gray, 
North Pacific right, and humpback whales, and belugas in U.S. waters of 
the Gulf of Alaska. BIAs are described in the following sections for 
each marine mammal species, except for beluga whale BIAs, as these do 
not co-occur within L-DEO's planned

[[Page 27250]]

survey area and the species is not expected to be present there. BIAs 
are delineated for feeding, migratory corridors, and small and resident 
populations. Supporting evidence for these BIAs came from aerial-, 
land-, and vessel-based surveys; satellite tagging data; passive 
acoustic monitoring; traditional ecological knowledge; photo- and 
genetic-identification data; whaling data, including catch and sighting 
locations and stomach contents; prey studies; and observations from 
fishermen.
    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, stock abundance estimates are 
not available, and survey abundance estimates are used. This survey 
area may or may not align completely with a stock's geographic range as 
defined in the SARs. For some species, this geographic area may extend 
beyond U.S. waters. All managed stocks in this region are assessed in 
NMFS's U.S. Alaska and U.S. Pacific SARs (e.g., Muto et al. 2018, 
Carretta 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 (Muto et al. 2018, Carretta 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).

                               Table 1--Marine Mammals That Could Occur in the Project Area During the Specified Activity
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                    ESA/ MMPA        Stock abundance
                                                                                     status;         (CV, Nmin, most                       Annual  M/SI
            Common name                Scientific name             Stock          strategic  (Y/    recent  abundance         PBR              \3\
                                                                                      N) \1\           survey) \2\
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                          Order Cetartiodactyla--Cetacea--Superfamily Mysticeti (baleen whales)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Family Eschrichtiidae:
    Gray whale....................  Eschrichtius robustus  Eastern North         -, -, N          26,960 (0.05,         801............  138
                                                            Pacific.                               25,849, 2016).
                                                           Western North         E, D, Y          175 (0.05, 167,       0.07...........  UNK
                                                            Pacific.                               2016).
Family Balaenidae:
    North Pacific right whale.....  Eubalaena japonica...  Eastern North         E, D, Y          31 (0.226, 26, 2015)  0.05 b.........  0
                                                            Pacific.
Family Balaenopteridae (rorquals):
    Blue whale....................  Balaenoptera musculus  Eastern North         E, D, Y          1,647 (0.07, 1,551,   2.3............  0.2
                                                            Pacific.                               2011).
                                                           Central North         E, D, Y          133 (1.09, 63, 2010)  0.1............  0
                                                            Pacific.
    Fin whale *\4\................  Balaenoptera physalus  Northeast Pacific...  E, D, Y          \4\ 3,168...........  5.1............  0.6
    Sei whale.....................  Balaenoptera borealis  Eastern North         E, D, Y          519 (0.4, 374, 2014)  0.75...........  0
                                                            Pacific.
    Minke whale *\5\..............  Balaenoptera           Alaska..............  -, -, N          \5\ 1,233...........  UND............  0
                                     acutorostrata.
Humpback whale....................  Megaptera              Central North         -, -, Y          10,103 (0.3, 7,890,   83.............  25
                                     novaeangliae.          Pacific.                               2006).
                                                           Western North         E, D, Y          1,107 (0.3, 865,      3..............  3.2
                                                            Pacific.                               2006).
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                            Superfamily Odontoceti (toothed whales, dolphins, and porpoises)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Family Physeteridae:
    Sperm whale *.................  Physeter               North Pacific.......  E, D, Y          N/A (see SAR, N/A,    see SAR........  4.4
                                     macrocephalus.                                                2015).
Family Ziphiidae (beaked whales):
Cuvier's beaked whale.............  Ziphius cavirostris..  Alaska..............  -, -, N          N/A (see SAR, N/A,    UND............  0
                                                                                                   see SAR).
    Baird's beaked whale..........  Berardius bairdii....  Alaska..............  -, -, N          N/A (see SAR, N/A,    UND............  0
                                                                                                   see SAR).
Stejneger's beaked whale..........  Mesoplodon stejnegeri  Alaska..............  -, -, N          N/A (see SAR, N/A,    UND............  0
                                                                                                   see SAR).
Family Delphinidae:
                                                           Eastern North         -, -, N          2,347 c (N/A, 2347,   24.............  1
                                                            Pacific Alaska                         2012).
                                                            Resident.
    Killer whale..................  Orcinus orca.........  Gulf of Alaska,       -, -, N          587 c (N/A, 587,      5.87...........  1
                                                            Aleutian Islands,                      2012).
                                                            and Bering Sea
                                                            Transient.
                                                           AT1 Transient.......  -, D, Y          7 c (N/A, 7, 2017)..  0.01...........  0
                                                           Offshore............  -, -, N          240 (0.49, 162,       1.6............  0
                                                                                                   2014).
    Risso's dolphin...............  Grampus griseus......  CA/WA/OR............  -, -, N          6,336 (0.32, 4,817,   46.............  >=3.7
                                                                                                   2014).
    Pacific white[dash]sided        Lagenorhynchus         North Pacific.......  -, -, N          26,880 (N/A, N/A,     UND............  0
     dolphin.                        obliquidens.                                                  1990).
Family Phocoenidae (porpoises):
    Harbor porpoise...............  Phocoena phocoena....  GOA.................  -, -, Y          31,046 (0.214, N/A,   UND............  72
                                                                                                   1998).
                                                           Southeast Alaska....  -, -, Y          see SAR (see SAR,     8.9............  34
                                                                                                   see SAR, 2012).
    Dall's porpoise...............  Phocoenoides dalli...  Alaska..............  -, -, N          83,400 (0.097, N/A,   UND............  38
                                                                                                   1991).
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                         Order Carnivora--Superfamily Pinnipedia
--------------------------------------------------------------------------------------------------------------------------------------------------------
Family Otariidae (eared seals and
 sea lions):
    Steller sea lion..............  Eumetopias jubatus...  Eastern U.S.........  T, D, Y          41,638 a (see SAR,    2498...........  108
                                                                                                   41,638, 2015).
                                                           Western U.S.........  E, D, Y          54,267 a (see SAR,    326............  252
                                                                                                   54,267, 2017).
    California sea lion...........  Zalophus               U.S.................  -, -, N          296,750 (N/A,         9200...........  389
                                     californianus.                                                153,337, 2011).
    Northern fur seal.............  Callorhinus ursinus..  Eastern Pacific.....  -, D, Y          620,660 (0.2,         11295..........  457
                                                                                                   525,333, 2016).
Family Phocidae (earless seals):
    Northern elephant seal........  Mirounga               California Breeding.  -, -, N          179,000 (N/A,         4882...........  8.8
                                     angustirostris.                                               81,368, 2010).

[[Page 27251]]

 
                                                           South Kodiak........  -, -, N          19,199 (see SAR,      314............  128
                                                                                                   17,479, 2011).
    Harbor seal...................  Phoca vitulina.......  Cook Inlet/Shelikof   -, -, N          27,386 (see SAR,      770............  234
                                                            Strait.                                25,651, 2011).
                                                           Prince William        -, -, N          29,889 (see SAR,      838............  279
                                                            Sound?.                                27,936, 2011).
--------------------------------------------------------------------------------------------------------------------------------------------------------
* Stocks marked with an asterisk are addressed in further detail in text below.
\1\ 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: https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessments assessments. CV is coefficient of variation; Nmin is the minimum estimate of stock abundance. In some cases, CV is not applicable (N/A).
\3\ These values, found in NMFS's SARs, represent annual levels of human-caused mortality plus serious injury from all sources combined (e.g.,
  commercial fisheries, ship strike).
\4\ Uncorrected estimate from Rone et al. (2017) based on a series of line-transect surveys off of Kodiak Island. The maximum estimate from the three
  surveys was selected. Based on the limited footprint of the surveys that lead to this estimate, the true abundance of the stock is expected to be much
  higher.
\5\ Uncorrected estimate from Zerbini et al., (2006) based on a partial line-transect survey of the Gulf of Alaska.
NOTE--Italicized species or stocks are not expected to be taken and no take is authorized.

    All species that could potentially occur in the planned survey 
areas are included in Table 1. With the exception of AT1 transient 
killer whales, these species or stocks temporally and spatially co-
occur with the activity to the degree that take is reasonably likely to 
occur. However, the spatial occurrence of the AT1 transient is such 
that take is not expected to occur, and they are not discussed further 
beyond the explanation provided here.
    A detailed description of the of the species likely to be affected 
by the Gulf of Alaska geophysical survey, 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 14200; April 9, 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 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]
------------------------------------------------------------------------
               Hearing group                 Generalized hearing range *
------------------------------------------------------------------------
Low-frequency (LF) cetaceans (baleen        7 Hz to 35 kHz.
 whales).
Mid-frequency (MF) cetaceans (dolphins,     150 Hz to 160 kHz.
 toothed whales, beaked whales, bottlenose
 whales).
High-frequency (HF) cetaceans (true         275 Hz to 160 kHz.
 porpoises, Kogia, river dolphins,
 cephalorhynchid, Lagenorhynchus cruciger
 & L. australis).
Phocid pinnipeds (PW) (underwater) (true    50 Hz to 86 kHz.
 seals).
Otariid pinnipeds (OW) (underwater) (sea    60 Hz to 39 kHz.
 lions and fur seals).
------------------------------------------------------------------------
* Represents the generalized hearing range for the entire group as a
  composite (i.e., all species within the group), where individual
  species' hearing ranges are typically not as broad. Generalized
  hearing range chosen based on ~65 dB threshold from normalized
  composite audiogram, with the exception for lower limits for LF
  cetaceans (Southall et al. 2007) and PW pinniped (approximation).

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

[[Page 27252]]

please see NMFS (2018) for a review of available information. Twenty-
one marine mammal species (16 cetacean and 5 pinniped (3 otariid and 2 
phocid) species) have the reasonable potential to co-occur with the 
planned survey activities. Please refer to Table 1. Of the 16 cetacean 
species that may be present, 7 are classified as low-frequency 
cetaceans (i.e., all mysticete species), 7 are classified as mid-
frequency cetaceans (i.e., all delphinid and ziphiid species and the 
sperm whale), and 2 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 airgun and other 
associated activities for the Gulf of Alaska geophysical survey have 
the potential to result in behavioral harassment and a small degree of 
PTS in marine mammals in the vicinity of the action area. The Federal 
Register notice for the proposed IHA (84 FR 14200; April 9, 2019) 
included a discussion of the effects of anthropogenic noise on marine 
mammals, therefore that information is not repeated here; please refer 
to the Federal Register notice (84 FR 14200; April 9, 2019) for that 
information.
    The main impact associated with the Gulf of Alaska 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 Gulf of Alaska 
geophysical survey. These potential effects are discussed in detail in 
the Federal Register notice for the proposed IHA (84 FR 14200; April 9, 
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.
    Since the proposed IHA, NMFS was made aware of errors in the 
calculations used to estimate ensonified area and determined there was 
reason to use an increased Steller sea lion density estimate. These 
changes resulted in an increase in the estimated take by Level A 
harassment for some species, and an increase in take by both Level A 
and Level B harassment for Steller sea lions. Additionally, to account 
for group behavior of marine mammals, the authorized number of takes by 
Level A harassment for some species has been increased to that of an 
average group size if the calculated value was smaller. These changes 
are discussed in greater detail below in the appropriate sections.
    Harassment is the only type of take expected to result from these 
activities and the only type of take that is authorized. 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 the acoustic source (i.e., 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) to result, primarily for high frequency species because 
predicted auditory injury zones are larger than for low-frequency 
species, mid-frequency species, phocids, and otariids. As a precaution, 
small numbers of takes by Level A harassment are authorized for many 
species listed in Table 1. Please see Table 9 below for additional 
further information on what species have authorized takes by Level A 
harassment. This auditory injury is expected to be, at most, low level 
PTS and the mitigation and monitoring measures are expected to further 
minimize the severity of such taking to the extent practicable.
    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 take estimates.

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 [mu]Pa (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 specified 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

[[Page 27253]]

survey includes the use of impulsive (seismic airguns) sources.
    These thresholds are provided in the Table 3 below. The references, 
analysis, and methodology used in the development of the thresholds are 
described in NMFS 2018 Technical Guidance, which may be accessed at 
https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-acoustic-technical-guidance.

 Table 3--Thresholds Identifying the Onset of Permanent Threshold Shift
                            in Marine Mammals
------------------------------------------------------------------------
                                          PTS onset thresholds
        Hearing group         ------------------------------------------
                                  Impulsive*          Non-impulsive
------------------------------------------------------------------------
Low-Frequency (LF) Cetaceans.  Lpk,flat: 219     LE,LF,24h: 199 dB
                                dB; LE,LF,24h:
                                183 dB.
Mid-Frequency (MF) Cetaceans.  Lpk,flat: 230     LE,MF,24h: 198 dB
                                dB; LE,MF,24h:
                                185 dB.
High-Frequency (HF) Cetaceans  Lpk,flat: 202     LE,HF,24h: 173 dB
                                dB; LE,HF,24h:
                                155 dB.
Phocid Pinnipeds (PW)          Lpk,flat: 218     LE,PW,24h: 201 dB
 (Underwater).                  dB; LE,PW,24h:
                                185 dB.
Otariid Pinnipeds (OW)         Lpk,flat: 232     LE,OW,24h: 219 dB
 (Underwater).                  dB; LE,OW,24h:
                                203 dB.
------------------------------------------------------------------------
Note: * 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]Pa2s. In this Table, thresholds are abbreviated to reflect
  American National Standards Institute standards (ANSI 2013). However,
  peak sound pressure is defined by ANSI as incorporating frequency
  weighting, which is not the intent for this Technical Guidance. Hence,
  the subscript ``flat'' is being included to indicate peak sound
  pressure should be flat weighted or unweighted within the generalized
  hearing range. The subscript associated with cumulative sound exposure
  level thresholds indicates the designated marine mammal auditory
  weighting function (LF, MF, and HF cetaceans, and PW and OW pinnipeds)
  and that the recommended accumulation period is 24 hours. The
  cumulative sound exposure level thresholds could be exceeded in a
  multitude of ways (i.e., varying exposure levels and durations, duty
  cycle). When possible, it is valuable for action proponents to
  indicate the conditions under which these acoustic thresholds will be
  exceeded.

Ensonified Area

    Here, we describe operational and environmental parameters of the 
activity that will feed into identifying the area ensonified above the 
acoustic thresholds, which include source levels and transmission loss 
coefficient.
    The planned surveys would acquire data with 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 
36-airgun array and 40-in\3\ airgun at a 12-m tow depth in deep water 
(>1000 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 (~1600 m), 
intermediate water depth on the slope (~600-1100 m), and shallow water 
(~50 m) in the Gulf of Mexico (GoM) 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 
~2000 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 mitigation 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 the 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 mitigation model curve. However, the observed sound levels are 
found to fall almost entirely below the mitigation model. Thus, 
analysis of the GoM calibration measurements demonstrates that although 
simple, the L-DEO model is a robust tool for conservatively estimating 
isopleths.
    In shallow water (<100 m), the depth of the calibration hydrophone 
(18 m) used during the GoM calibration survey was appropriate to sample 
the maximum sound level in the water column, and the field measurements 
reported in Table 1 of Tolstoy et al. (2009) for the 36-airgun array at 
a tow depth of 6 m can be used to derive isopleths.
    For deep water (<1000 m), we use the deep-water radii obtained from 
L-DEO model results down to a maximum water depth of 2000 m. The radii 
for intermediate water depths (100-1000 m) are derived from the deep-
water ones by applying a correction factor (multiplication) of 1.5, 
such that observed levels at very near offsets fall below the corrected 
mitigation curve (Fig. 16 in Appendix H of the NSF-USGS, 2011).
    The shallow-water radii are obtained by scaling the empirically 
derived measurements from the GoM calibration survey to account for the 
differences in tow depth between the calibration survey (6 m) and the 
planned survey (12 m); whereas the shallow water in the GoM may not 
exactly replicate the shallow water environment at the specified survey 
site, it has been shown to serve as a good and very conservative proxy 
(Crone et al. 2014). A simple scaling factor is calculated from the 
ratios of the isopleths determined by the deep-water L-DEO model, which 
are essentially a measure of the energy radiated by the source array.
    Measurements have not been reported for the single 40-in\3\ airgun. 
L-DEO

[[Page 27254]]

model results are used to determine the 160 dBrms radius for 
the 40-in\3\ airgun at a 12-m tow depth in deep water (Fig. A-3 in the 
IHA application). For intermediate-water depths, a correction factor of 
1.5 was applied to the deep-water model results. For shallow water, a 
scaling of the field measurements obtained for the 36-airgun array was 
used.
    L-DEO's modeling methodology is described in greater detail in the 
IHA application. The estimated distances to the Level B harassment 
isopleth for the Langseth's 36-airgun array and single 40-in\3\ airgun 
are shown in Table 4.

   Table 4--Predicted Radius from R/V Langseth Seismic Source to Isopleths Corresponding to Level B Harassment
                                                    Threshold
----------------------------------------------------------------------------------------------------------------
                                                                                             Predicted distances
                                                                               Water depth    (in m) to the 160-
                     Source and volume                        Tow depth (m)        (m)        dB Received Sound
                                                                                                    Level
----------------------------------------------------------------------------------------------------------------
Single Bolt airgun, 40 in\3\...............................              12         >1000 m              \1\ 431
                                                                                 100-1000 m              \2\ 647
                                                                                     <100 m            \3\ 1,041
4 strings, 36 airguns, 6600 in\3\..........................              12         >1000 m            \1\ 6,733
                                                                                 100-1000 m           \2\ 10,100
                                                                                     <100 m           \3\ 25,494
----------------------------------------------------------------------------------------------------------------
\1\ Distance is based on L-DEO model results.
\2\ Distance is based on L-DEO model results with a 1.5 x correction factor between deep and intermediate water
  depths.
\3\ Distance is based on empirically derived measurements in the GoM with scaling applied to account for
  differences in tow depth.

    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 2016a). 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 farfield 
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.
    In order to more realistically incorporate the Technical Guidance's 
weighting functions over the seismic array's full acoustic band, 
unweighted spectrum data for the Langseth's airgun array (modeled in 1 
Hz bands) was used to make adjustments (dB) to the unweighted spectrum 
levels, by frequency, according to the weighting functions for each 
relevant marine mammal hearing group. These adjusted/weighted spectrum 
levels were then converted to pressures ([mu]Pa) in order to integrate 
them over the entire broadband spectrum, resulting in broadband 
weighted source levels by hearing group that could be directly 
incorporated within the User Spreadsheet (i.e., to override the 
Spreadsheet's more simple weighting factor adjustment). These hearing 
group specific weighted source levels are presented in Table 5 below.

[[Page 27255]]



      Table 5--Modeled Source Levels Based on Modified Farfield Signature for the R/V Langseth 6,600 in\3\ Airgun Array, and Single 40 in\3\ Airgun
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                             Low frequency      Mid frequency      High frequency    Phocid Pinnipeds  Otariid 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)
 
--------------------------------------------------------------------------------------------------------------------------------------------------------
6,600 in\3\ airgun array (Peak SPLflat)..................             252.06             252.65             253.24             252.25             252.52
6,600 in\3\ airgun array (SELcum)........................             232.98             232.84             233.10             232.84             232.08
40 in\3\ airgun (Peak SPLflat)...........................             223.93               N.A.             223.92             223.95               N.A.
40 in\3\ airgun (SELcum).................................             202.99             202.89             204.37             202.89             202.35
--------------------------------------------------------------------------------------------------------------------------------------------------------

    Using the User Spreadsheet's ``safe distance'' methodology for 
mobile sources (described by Sivle et al., 2014) with the hearing 
group-specific weighted source levels, and inputs assuming spherical 
spreading propagation and source velocities and shot intervals provided 
in the IHA application, potential radial distances to auditory injury 
zones were then calculated for SELcum thresholds (Table 6).
    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 36-airgun array and single 40 
in\3\ airgun for the surveys are shown is Tables A-2, A-3, A-5, and A-8 
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 Radius (m) to Isopleths Corresponding to Level A Harassment Thresholds
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                             Low frequency      Mid frequency      High frequency    Phocid Pinnipeds  Otariid 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)
 
--------------------------------------------------------------------------------------------------------------------------------------------------------
6,600 in\3\ airgun array (Peak SPLflat)..................               38.9               13.6              268.3               43.7               10.6
6,600 in\3\ airgun array (SELcum)........................               40.1               N.A.                0.1                1.3               N.A.
40 in\3\ airgun (Peak SPLflat)...........................               1.76               N.A.               12.5               1.98               N.A.
40 in\3\ airgun (SELcum).................................               2.38               N.A.               N.A.               N.A.               N.A.
--------------------------------------------------------------------------------------------------------------------------------------------------------

    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.
    Since the proposed IHA, NMFS identified a more appropriate inshore 
density estimate for Steller sea lions, as reported in Table 7, 
changing it from 0.0098 individuals/km\2\ to 0.0392 individuals/km\2\. 
This change was made after discussion with the Commission and 
determining that the density value used by the Navy, which was 
corrected to account for the proportion of Steller sea lions expected 
to be at sea, may not be the best proxy for L-DEO's survey area. 
Because the Navy's action area was located in a more offshore portion 
of the Gulf of Alaska and only a portion (25 percent) of Steller sea 
lions were expected to be feeding at-sea, the Navy applied a 0.25 
correction factor to the calculated density of Steller sea lions for 
the Gulf of Alaska Large Marine Ecosystem. L-DEO's survey does include 
areas closer to shore, so the use of this corrected density estimate 
may have resulted in underestimating Steller sea lion take. In this 
final IHA, we account for the difference in action areas by removing 
the Navy's correction factor and the updating the inshore density used 
to generate final take estimates to 0.0392 individuals/km\2\ (0.0098 * 
4). The density for deeper strata remains at 0.0098 individuals/km\2\ 
for L-DEO's planned survey. The resulting increases in take by Level A 
and Level B harassment are displayed in Table 9.
    Additionally, the estimates of take by Level A harassment in the 
proposed IHA did not accurately account for the 18 day duration of the 
survey. To correct this, Table 8 explaining the derivation of 
ensonified areas has been adjusted and the resulting take by Level A 
harassment for all species has been increased as needed (Table 9). As 
in the proposed IHA, the estimated number of takes by Level B 
harassment has been reduced by the numbers of take by Level A 
harassment to avoid double counting of an individual animal exposed to 
both levels of harassment.
    Additionally, all proposed takes by Level A harassment for mid-
frequency cetaceans were removed, and there is no take by Level A 
harassment authorized for species in this hearing group. This removal 
was based on consideration of the small calculated Level A harassment 
zone and the properties of sound fields produced by arrays in the near 
field versus far field which logically lead to the conclusion that 
Level A harassment is so unlikely for this hearing group as to be 
discountable. Estimated takes by Level A harassment which were 
presented in the proposed IHA have been added as takes by Level B 
harassment to ensure all marine mammals estimated to be in the 
ensonified area are accounted for.

[[Page 27256]]

    Finally, for some species, including blue whale, sei whale, and 
minke whale, the number of proposed takes by Level A harassment was 
increased to the average group size to conservatively account for how 
these species may be encountered during the survey. These changes are 
explained in Table 9.
    In the planned survey area in the Gulf of Alaska, L-DEO determined 
the best marine mammal density data to be habitat-based stratified 
marine mammal densities developed by the U.S. Navy for assessing 
potential impacts of training activities in the GOA (DoN 2014). 
Alternative density estimates available for species in this region are 
not stratified by water depth and therefore do not reflect the known 
variability in species distribution relative to habitat features. 
Consistent with Rone et al. (2014), four strata were defined: Inshore: 
All waters <1000 m deep; Slope: From 1000 m water depth to the Aleutian 
trench/subduction zone; Offshore: Waters offshore of the Aleutian 
trench/subduction zone; Seamount: Waters within defined seamount areas. 
Densities corresponding to these strata were based on data from several 
different sources, including Navy funded line-transect surveys in the 
GOA as described below and in Appendix B.
    To develop densities specific to the GOA, the Navy conducted two 
comprehensive marine mammal surveys in the Temporary Marine Activities 
Area (TMAA) in the GOA prior to 2014. The first survey was conducted 
from 10 to 20 April 2009 and the second was from 23 June to 18 July 
2013. Both surveys used systematic line-transect survey protocols 
including visual and acoustic detection methods (Rone et al. 2010; Rone 
et al. 2014). The data were collected in four strata that were designed 
to encompass the four distinct habitats within the TMAA and greater 
GOA. Rone et al. (2014) provided stratified line-transect density 
estimates used in this analysis for fin, humpback, blue, sperm, and 
killer whales, as well as northern fur seals (Table 7). Data from a 
subsequent survey in 2015 were used to calculate alternative density 
estimates for several species (Rone et al. 2017) and the density 
estimates for Dall's porpoise used here were taken from that source.
    DoN (2014) derived gray whale densities in two zones, nearshore (0-
2.25 n.mi from shore) and offshore (from 2.25-20 nmi from shore). In 
our calculations, the nearshore density was used to represent the 
inshore zone and the offshore density was used to represent the slope 
zone.
    Harbor porpoise densities in DoN (2014) were derived from Hobbs and 
Waite (2010) which included additional shallow water depth strata. The 
density estimate from the 100 m to 200 m depth strata was 
conservatively used to represent the entire inshore zone (<1000 m) in 
this analysis.
    Harbor seals typically remain close to shore so minimal estimates 
were used for the three deep water zones. To account for increased 
inshore density, a one thousand fold increase of the minimal density 
was assumed to represent the entire inshore zone (DoN 2014).
    Densities for Minke whale, Pacific white-sided dolpin, and Cuvier's 
and Baird's beaked whales were based on Waite (2003 in DoN 2009). 
Although sei whale sightings and Stejneger's beaked whale acoustic 
detections were recorded during the Navy funded GOA surveys, data were 
insufficient to calculate densities for these species, so predictions 
from a global model of marine mammals densities were used (DoN 2014).
    Steller sea lion and northern elephant seal densities were 
calculated using shore-based population estimates divided by the area 
of the GOA Large Marine Ecosystem (DoN 2014). As mentioned above, in 
the proposed IHA, the values for Steller sea lion were corrected to 
account for the proportion of the population that would be encountered 
at sea. For the final IHA, Steller sea lion inshore density was 
increased to 0.0392 individuals/km\2\, by eliminating the Navy's 
correction factor, to account for L-DEO's more inshore activity when 
compared to the Navy's.
    The North Pacific right whale, Risso's dolphin, and California sea 
lion are only rarely observed in or near the survey area, so minimal 
densities were used to represent their potential presence. However, in 
the North Pacific right whale critical habitat off of Kodiak Island, it 
is reasonable to expect a higher density. In this critical habitat 
area, the Alaska Fisheries Science Center (LOA application available 
here: https://www.fisheries.noaa.gov/national/marine-mammal-protection/incidental-take-authorizations-research-and-other-activities) used a 
conservative density estimate based on acoustic detections (Rone et al. 
2014) and photo identifications throughout the entirety of the Gulf of 
Alaska. For the portion of L-DEO's activities that occur in North 
Pacific right whale critical habitat, NMFS will use this more 
conservative density estimate (Table 7).
    All densities were corrected for perception bias [f(0)] but only 
harbor porpoise densities were corrected for availability bias [g(0)], 
as described by the respective authors. There is some uncertainty 
related to the estimated density data and the assumptions used in their 
calculations, as with all density data estimates. However, the approach 
used here is based on the best available data and are stratified by the 
water depth (habitat) zones present within the survey area. These depth 
stratified densities allow L-DEO to better capture known variability in 
species distribution in the Gulf of Alaska, and accurately assess 
impacts. Alternative density estimates were available for species in 
this region, such as those used by the Alaska Fisheries Science Center 
(AFSC) (AFSC LOA application available here: https://www.fisheries.noaa.gov/national/marine-mammal-protection/incidental-take-authorizations-research-and-other-activities). AFSC density values 
were not stratified by water depth and represented marine mammal 
density throughout the entire Gulf of Alaska. While some density 
estimates provided in the AFSC application are more conservative, the 
relative proximity of surveys that generated DoN estimates and L-DEO's 
consideration and inclusion of publically available newer values from 
Rone et al. (2017) mean the calculated exposures that are based on 
these densities are best estimates for L-DEO's planned survey.

                   Table 7--Marine Mammal Density Values in the Planned Survey Area and Source
----------------------------------------------------------------------------------------------------------------
                                                  Estimated density (#/km\2\)
                               ----------------------------------------------------------------
                                                                   Offshore      Seamount (in
          Species \1\           Inshore (<1000   Slope (1000 m   (offshore of       defined          Source
                                      m)          to Aleutian      Aleutian        seamount
                                                    Trench)         Trench)         areas)
----------------------------------------------------------------------------------------------------------------
LF Cetaceans:
    North Pacific Right Whale.     \2\ 0.00001     \2\ 0.00001     \2\ 0.00001     \2\ 0.00001  DoN (2014).

[[Page 27257]]

 
    Humpback Whale............           0.129          0.0002           0.001           0.001  Rone et al.
                                                                                                 (2014) (Table
                                                                                                 16).
    Blue whale................          0.0005          0.0005          0.0005           0.002  Rone et al.
                                                                                                 (2014) (Table
                                                                                                 16).
    Fin Whale.................           0.071           0.014           0.021           0.005  Rone et al.
                                                                                                 (2014) (Table
                                                                                                 16).
    Sei Whale.................          0.0001          0.0001          0.0001          0.0001  DoN (2014),
                                                                                                 adapted from
                                                                                                 Figure 5-24.
    Minke Whale...............          0.0006          0.0006          0.0006          0.0006  DoN (2014).
    Gray Whale................     \3\ 0.04857     \3\ 0.00243           \3\ 0           \3\ 0  DoN (2014).
MF Cetaceans:
    Sperm Whale...............               0          0.0033          0.0013         0.00036  DoN (2014).
    Killer Whale..............           0.005            0.02           0.002           0.002  Rone et al.
                                                                                                 (2014) (Table
                                                                                                 14).
    Pacific White-Sided                 0.0208          0.0208          0.0208          0.0208  DoN (2014).
     Dolphin.
    Cuvier's Beaked Whale.....          0.0022          0.0022          0.0022          0.0022  Waite (2003) in
                                                                                                 DoN (2014).
    Baird's Beaked Whale......          0.0005          0.0005          0.0005          0.0005  DoN (2014).
    Stejneger's Beaked Whale..     \4\ 0.00001         0.00142         0.00142         0.00142  DoN (2014),
                                                                                                 adapted from
                                                                                                 Figure 9-12.
    Risso's Dolphin...........         0.00001         0.00001         0.00001         0.00001  DoN (2014).
HF Cetaceans:
    Harbor Porpoise...........          0.0473               0               0               0  Hobbes and Waite
                                                                                                 (2010) in DoN
                                                                                                 (2014).
    Dall's Porpoise...........           0.218           0.196           0.037           0.024  Rone et al.
                                                                                                 (2017).
Otarrid Seals:
    Steller Sea Lion..........          0.0392          0.0098          0.0098          0.0098  DoN (2014).
    California Sea Lion.......         0.00001         0.00001         0.00001         0.00001  DoN (2014).
    Northern Fur Seal.........           0.015           0.004           0.017           0.006  Rone et al.
                                                                                                 (2014) (Table
                                                                                                 14).
Phocid Seals:
    Northern Elephant Seal....          0.0022          0.0022          0.0022           0.022  DoN (2014).
    Harbor Seal...............            0.01         0.00001         0.00001         0.00001  DoN (2014).
----------------------------------------------------------------------------------------------------------------
\1\ No stock specific densities are available so densities are assumed equal for all stocks present.
\2\ For North Pacific right whales, estimated density within the Kodiak Island critical habitat is 0.0053
  animals/km\2\, based on detections from the GOALSII survey (Rone et al. 2014), the assumed use of the critical
  habitat by all right whales in the Gulf of Alaska (Wade et al. 2011a), and a conservative correction factor.
\3\ Gray whale density was defined in two zones, nearshore (0-2.25 n.mi from shore) and offshore (from 2.25-20
  nmi from shore). In our calculations, the nearshore density was used to represent the inshore zone and the
  offshore density was used to represent the slope zone. In areas further offshore than the slope, density was
  assumed to be 0.
\4\ Stejneger's whale are generally found in slope waters, therefore, assuming minimal inshore density.

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 harassment or Level B harassment, the 
radius 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 harassment 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 the estimated 
trackline distance traveled per day. This number is then multiplied by 
the number of survey days. Active seismic operations are planned for 18 
days during this Gulf of Alaska survey.

            Table 8--Areas (km\2\) Estimated To Be Ensonified to Level A and Level B Harassment Thresholds, per Day for Gulf of Alaska Survey
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                             Increased
                                                               Daily        25 Percent         daily       Total survey        Total         Relevant
                                             Criteria       ensonified       increase       ensonified         days         ensonified     isopleth (m)
                                                           area (km\2\)                    area (km\2\)                    area (km\2\)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Level B:
    Inshore \1\.........................          160 dB          1963.1            1.25          2453.9              18        44,170.2         10,100,
                                                                                                                                              \1\ 25,493
    Slope...............................          160 dB           684.1            1.25           855.2              18        15,393.6           6,733
    Offshore............................          160 dB          1159.5            1.25          1449.3              18        26,087.4           6,733
    Seamount............................          160 dB           119.8            1.25           149.7              18         2,694.6           6,733
--------------------------------------------------------------------------------------------------------------------------------------------------------
Level A:
    LF Cetacean.........................  ..............            19.6            1.25            24.5              18           441.0            40.1
    MF Cetacean.........................  ..............             6.6            1.25             8.3              18           149.4            13.6
    HF Cetacean.........................  ..............           131.1            1.25           163.5              18          2950.2           268.3
    Otarid..............................  ..............             5.2            1.25             6.5              18           117.0            10.6
    Phocid..............................  ..............            21.4            1.25            26.7              18           480.6            43.7
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ Includes area ensonified above 160 dB in waters <100 m deep using an isopleth distance of 25,493 m. See application for further explanation.


[[Page 27258]]

    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 harassment 
and Level B harassment thresholds. The marine mammals predicted to 
occur within these respective areas, based on estimated densities, are 
assumed to be incidentally taken. Estimated exposures for the Gulf of 
Alaska seismic survey are shown in Table 9.

 Table 9--Estimated Level A and Level B Exposures, and Percentage of Stock or Population Exposed During Gulf of
                                                  Alaska Survey
----------------------------------------------------------------------------------------------------------------
                                                                                                   Percentage of
                                      Stock         Level B \1\     Level A \1\     Stock size         stock
----------------------------------------------------------------------------------------------------------------
LF Cetaceans:
    North Pacific Right Whale.  Eastern North             \2\ 11               0              31         \3\ <33
                                 Pacific.
    Humpback Whale............  Central North          \4\ 5,079              21          11,398         \3\ <33
                                 Pacific (Hawaii
                                 DPS) \3\.
                                Central North            \4\ 599               3           3,264           18.44
                                 Pacific (Mexico
                                 DPS) \3\.
                                Western North             \4\ 28               1           1,107            2.62
                                 Pacific \3\.
    Blue whale................  Eastern North                 47           5 6 2           1,647            2.98
                                 Pacific.
                                Central North                                                133         \3\ <33
                                 Pacific.
    Fin Whale.................  Northeast                  3,897              16       \7\ 3,168         \3\ <33
                                 Pacific.
    Sei Whale.................  Eastern North                  7           \6\ 2             519            1.73
                                 Pacific.
    Minke Whale...............  Alaska..........              52           \6\ 2       \8\ 1,233            4.38
    Gray Whale................  Eastern North              2,174           \5\ 9          26,960            8.10
                                 Pacific.
                                Western North                                                175         \3\ <33
                                 Pacific.
----------------------------------------------------------------------------------------------------------------
MF Cetaceans:
    Sperm Whale...............  North Pacific...              86           \9\ 0        \10\ 345           24.93
    Killer Whale..............  Alaska Resident.             587           \9\ 0           2,347           25.01
                                Gulf of Alaska,                                              587         \3\ <33
                                 Aleutian
                                 Islands, and
                                 Bering Sea
                                 Transient.
                                Offshore.                                                    240         \3\ <33
    Pacific White-Sided         North Pacific...           1,838           \9\ 0          26,880            6.84
     Dolphin.
    Cuvier's Beaked Whale.....  Alaska..........             195           \9\ 0         \11\ NA              NA
    Baird's Beaked Whale......  Alaska..........              45           \9\ 0         \11\ NA              NA
    Stejneger's Beaked Whale..  Alaska..........              64           \9\ 0         \11\ NA              NA
    Risso's Dolphin...........  CA/OR/WA........         \12\ 16           \9\ 0           6,336            0.25
----------------------------------------------------------------------------------------------------------------
HF Cetaceans:
    Harbor Porpoise...........  Gulf of Alaska..      \13\ 1,830         \13\ 51          31,046       \13\ 6.06
                                Southeast Alaska        \13\ 203          \13\ 6             975      \13\ 21.74
    Dall's Porpoise...........  Alaska..........          13,196             481          83,400           16.44
----------------------------------------------------------------------------------------------------------------
Otariid Seals:
    Steller Sea Lion..........  Eastern U.S.....           2,165           \5\ 3          41,638            5.21
                                Western U.S.                                              54,267            4.00
    California Sea Lion.......  U.S.............          \14\ 1               1         296,750         0.00067
    Northern Fur Seal.........  Eastern Pacific.           1,182               2         620,660            0.19
----------------------------------------------------------------------------------------------------------------
Phocid Seals:
    Northern Elephant Seal....  California                   193               2         179,000            0.11
                                 Breeding.
    Harbor Seal...............  South Kodiak....             441           \5\ 2          19,199            2.31
                                Cook Inlet/                                               27,386            1.62
                                 Shelikof
                                 Strait.
                                Prince William                                            29,889            1.48
                                 Sound.
----------------------------------------------------------------------------------------------------------------
\1\ Unless otherwise noted, all calculated takes by Level B harassment have been reduced by the number of
  authorized takes by Level A harassment. This prevents double counting of takes across the two levels of
  harassment.
\2\ NMFS feels that take by Level A harassment of North Pacific right whale can be effectively avoided based on
  mitigation and monitoring measures, and therefore has not authorized take by Level A harassment for the
  species.
\3\ The percentage of these stocks expected to experience take is discussed further in the Small Numbers section
  later in the document.
\4\ Takes are allocated amongst the three DPSs in the area based on Wade et al. 2016 (0.5% WNP, 89.0% Hawaii
  DPS, 10.5% Mexico DPS). Because of rounding, the total take is higher than calculated. Population sizes for
  the Hawaii and Mexican DPSs are provided in 81 FR 62259 (effective October 11, 2016).
\5\ Where multiple stocks are being affected and there is no clear method to allocate takes between stocks, for
  the purposes of calculating the percentage of the stock impacted, takes by Level A harassment are being
  analyzed as if it occurred within each stock.
\6\ Authorized take by Level A harassment was raised to the approximate group size for these species. Group
  estimates were based on Rone et al. (2017) (Blue whale), NOAA Fisheries Species page (https://www.fisheries.noaa.gov/species/sei-whale) (Sei whale), and Zerbini et al. (2006) (Minke whale).
\7\ Fin whale abundance estimate is the highest of Rone et al. (2017) estimates. Based on the limited footprint
  of the surveys that lead to this estimate, the true abundance of the stock is expected to be much higher.
\8\ Minke whale abundance estimates is from Zerbini et al. (2006).
\9\ In the proposed Federal Register notice, NMFS proposed to authorize 1 take by Level A harassment for each
  species in the MF Cetacean hearing group. Based on the small Level A harassment zone, NMFS believes these
  takes by Level A harassment are not necessary for this action.
\10\ Sperm whale abundance estimates is the maximum value from Rone et al. (2017).
\11\ For beaked whales, there is no accepted estimates of abundance for the Alaska stocks.
\12\ The requested number of takes by Level B harassment for Risso's dolphin has been increased to 16, the
  average group size.
\13\ Based on the range of the Southeast Alaska stock of harbor porpoises, they are expected to be very rare in
  the area (See ``Description of Marine Mammals in the Area of Specified Activities''). We therefore
  conservatively assume that at most, 10 percent of takes will occur from the Southeast Alaska population. The
  numbers for both Gulf of Alaska and Southeast Alaska stocks reflect this assumption. Because of rounding, the
  total take between the two stocks is higher than the original calculation.
\14\ Only 1 take by Level B harassment was requested for California sea lion, but a take by Level A harassment
  was also requested. Therefore, the amount of take by Level B harassment has not be reduced by the number of
  takes by Level A harassment.

    It should be noted that the 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

[[Page 27259]]

used to estimate take as described above. Additionally, marine mammals 
would be expected to move away from 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.
    For North Pacific right whale, there is evidence of a much higher 
density in the critical habitat south of Kodiak Island (Table 7). This 
density value of 0.0053 animals/km\2\ is based on detections from the 
GOALSII survey (4 individuals) (Rone et al., 2014), the assumed use of 
the critical habitat by all right whales in the Gulf of Alaska (Wade et 
al., 2011a), and a conservative correction factor (4), all divided by 
the area of the critical habitat (3,042.2 km\2\). To account for this 
habitat, NMFS used the Alaska Protected Resources Division Species 
Distribution Mapper (https://www.fisheries.noaa.gov/resource/data/alaska-endangered-species-and-critical-habitat-mapper-web-application) 
to determine a conservative approximation of L-DEO's survey path 
through the critical habitat based on the representative tracks in 
Figure 1 of the IHA Application. This measured distance was 35 km. 
Because the majority of this habitat is inside of the 100 m isopleth, 
the predicted distance to the 160-dB received sound level would be 
~25.5 km. This resulted in a portion of the critical habitat 35 km long 
by 51 km wide (25.5 km on each side of the survey track), or 1,785 
km\2\ being ensonified. Applying the higher density of 0.0053 animals/
km\2\ to this area, results in an estimate of 9.46 North Pacific right 
whales exposed to Level B harassment in the critical habitat. No 
further correction, such as the 25 percent operation day increase, is 
needed for the estimate in the critical habitat, because the density of 
0.0053 animals/km\2\ has already been corrected to be highly 
conservative (AFSC Application, Table 6-10d). To account for the rest 
of the survey occurring outside of the critical habitat, the minimal 
density presented in DoN (2014), 0.00001 individuals/km\2\, was used 
for the remainder of the survey. The expected take in the rest of the 
survey is 1.10 individuals. Summing these two estimates for take, in 
both the critical habitat and remainder of survey, results in an 
expected take of 10.56 individuals (rounded to 11 individuals). No 
takes by Level A harassment are authorized for North Pacific right 
whale given the low density of the species and NMFS evaluation of the 
effectiveness of mitigation and monitoring measures.

Effects of Specified Activities on Subsistence Uses of Marine Mammals

    The availability of the affected marine mammal stocks or species 
for subsistence uses may be impacted by this activity. The subsistence 
uses that may be affected and the potential impacts of the activity on 
those uses are described below. Measures included in this IHA to reduce 
the impacts of the activity on subsistence uses are described in the 
Mitigation section. Last, the information from this section and the 
Mitigation section is analyzed to determine whether the necessary 
findings may be made in the Unmitigable Adverse Impact Analysis and 
Determination section.
    In the GOA, the marine mammals that are hunted are Steller sea 
lions and harbor seals. In 2011-2012, 37 harbor seals were taken from 
the North Kodiak Stock and 126 harbor seals were taken from the South 
Kodiak Stock by communities on Kodiak Island (Muto et al. 2016). The 
number taken from the Cook Inlet/Shelikof Strait Stock for 2011-2012 is 
unknown, but an average of 233 were taken from this stock annually 
during 2004-2008 (Muto et al. 2016). The seasonal distribution of 
harbor seal takes by Alaska Natives typically shows two distinct 
hunting peaks--one during spring and one during fall and early winter; 
however, seals are taken in all months (Wolfe et al. 2012). In general, 
the months of highest harvest are September through December, with a 
smaller peak in February/March (Wolfe et al. 2012). Harvests are 
traditionally low from May through August, when harbor seals are 
raising pups and molting.
    In 2008, 19 Steller sea lions were taken in the Kodiak Island 
region and 9 were taken along the South Alaska Peninsula (Wolfe et al. 
2009). As of 2009, data on community subsistence harvests are no longer 
being collected consistently so few data are available. Wolfe et al. 
(2012) reported an estimated 20 sea lions taken by hunters on Kodiak 
Island in 2011. The most recent 5-year period with data available 
(2004-2008) shows an annual average catch of 172 steller sea lions for 
all areas in Alaska combined except the Pribilof Islands in the Bering 
Sea (Muto et al. 2018). Sea lions are taken from Kodiak Island in low 
numbers year round (Wolfe et al. 2012).
    During the process of planning their survey, L-DEO and its 
representatives contacted organizations associated with subsistence 
harvest of marine mammals the Gulf of Alaska and requested their 
comment on the Draft EA, which included information on marine mammal 
impacts. The groups contacted included the Alaska Native Harbor Seal 
Commission, the Alaska Sea Otter and Steller Sea Lion Commission, and 
the Aleut Marine Mammal Commission. L-DEO and its representatives 
received no comment from these groups.
    The planned project could potentially impact the availability of 
marine mammals for harvest in a small area immediately around the 
Langseth, and for a very short time period during seismic operations. 
Considering the limited time that the planned seismic surveys would 
take place close to shore, where most subsistence harvest of marine 
mammals occurs in the Gulf of Alaska, the planned project is not 
expected to have any significant impacts to the availability of Steller 
sea lions or harbor seals for subsistence harvest. Additionally, to 
mitigate any possible conflict, community outreach is planned and 
described further in Mitigation below.

Mitigation

    In order to issue an IHA under Section 101(a)(5)(D) of the MMPA, 
NMFS must set forth the permissible methods of taking pursuant to such 
activity, and other means of effecting the least practicable impact on 
such species or stock and its habitat, paying particular attention to 
rookeries, mating grounds, and areas of similar significance, and on 
the availability of such species or stock for taking for certain 
subsistence uses. NMFS regulations require applicants for incidental 
take authorizations to include information about the availability and 
feasibility (economic and technological) of equipment, methods, and 
manner of conducting such activity or other means of effecting the 
least practicable adverse impact upon the affected species or stocks 
and their habitat (50 CFR 216.104(a)(11)).
    In evaluating how mitigation may or may not be appropriate to 
ensure the least practicable adverse impact on species or stocks and 
their habitat, as well as subsistence uses where applicable, we 
carefully consider two primary factors:
    (1) The manner in which, and the degree to which, the successful 
implementation of the measure(s) is expected to reduce impacts to 
marine mammals, marine mammal species or stocks, and their habitat, as 
well as subsistence uses. This considers the nature of the potential 
adverse impact being mitigated (likelihood, scope, range). It further 
considers the

[[Page 27260]]

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 mitigation measures into their 
project description based on the above sources. Since the proposed IHA, 
NMFS has clarified that the seismic array must be immediately shutdown 
if a marine mammal species not authorized for take, or a species which 
has reached its authorized number of takes, is observed entering or 
approaching the Level B harassment zone. This measure will prevent the 
unauthorized harassment of any marine mammal species.
    To reduce the potential for disturbance from acoustic stimuli 
associated with the activities, L-DEO will implement mitigation 
measures for marine mammals. Mitigation measures that would be adopted 
during the planned survey 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; (7) Vessel strike 
avoidance measures; and (8) Sensitive Habitat 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 six 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 (rather than being based on the center of the array 
or around the vessel itself).
    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) shall 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

[[Page 27261]]

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 an Exclusion Zone and Buffer Zone

    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 for the 36 airgun array. 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.
    Because the North Pacific right whale is a stock of high concern, 
L-DEO will implement a shutdown if the species is observed at any 
distance. In addition, when transiting through North Pacific right 
whale critical habitat, L-DEO must conduct any survey operations during 
daylight hours, to facilitate the ability of PSOs to observe any right 
whales that may be present. If transit through the North Pacific right 
whale critical habitat is required during darkness, or conditions of 
similar limited visibility, L-DEO must reduce vessel speed to at most 5 
kn (knots) while in this critical habitat. Additionally, for high risk 
circumstances, such as observation of a calf or aggregation of large 
whales (defined as 6 or more mysticetes or sperm whales), L-DEO will 
shutdown if these circumstances are observed at any distance.
    Finally, to minimize impact on fin whales in their feeding BIA near 
Kodiak Island, L-DEO must observe a larger EZ for this species while in 
the BIA. If a fin whale or group of fin whales is observed with 1,500 m 
of the acoustic source within the fin whale BIA, L-DEO must implement a 
shutdown.

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 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

[[Page 27262]]

pinnipeds and 30 minutes for all other species);
     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. The array must also be 
immediately shutdown whenever a marine mammal species not authorized 
for take, or a species which has reached its authorized number of 
takes, is observed entering or approaching the Level B harassment zone. 
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 Cuvier's 
beaked, Baird's beaked, Stejneger's beaked, and killer whales.
    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 would apply solely to specific genera of small dolphins --
Lagenorhynchus and Grampus--The acoustic source shall 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 delphinid exception because power-down/
shutdown requirements for small delphinids under all circumstances 
represent practicability concerns without likely commensurate benefits 
for the animals in question. Small delphinids are generally the most 
commonly observed marine mammals in the specific geographic region and 
would typically be the only marine mammals likely to intentionally 
approach the vessel. As described above, auditory injury is extremely 
unlikely to occur for mid-frequency cetaceans (e.g., delphinids), as 
this group is relatively insensitive to sound produced at the 
predominant frequencies in an airgun pulse while also having a 
relatively high threshold for the onset of auditory injury (i.e., 
permanent threshold shift).
    A large body of anecdotal evidence indicates that small delphinids 
commonly approach vessels and/or towed arrays during active sound 
production for purposes of bow riding, with no apparent effect observed 
in those delphinids (e.g., Barkaszi et al., 2012). The potential for 
increased shutdowns resulting from such a measure would require the R/V 
Langseth to revisit the missed track line to reacquire data, resulting 
in an overall increase in the total sound energy input to the marine 
environment and an increase in the total duration over which the survey 
is active in a given area. Although other mid-frequency hearing 
specialists (e.g., large delphinids) are no more likely to incur 
auditory injury than are small delphinids, they are much less likely to

[[Page 27263]]

approach vessels. Therefore, retaining a power-down/shutdown 
requirement for large delphinids would not have similar impacts in 
terms of either practicability for the applicant or corollary increase 
in sound energy output and time on the water. We do anticipate some 
benefit for a power-down/shutdown requirement for large delphinids in 
that it simplifies somewhat the total range of decision-making for PSOs 
and may preclude any potential for physiological effects other than to 
the auditory system as well as some more severe behavioral reactions 
for any such animals in close proximity to the source vessel.
    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 all other species with no further 
observation of the marine mammal(s).

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.

Sensitive Habitat Measures

    Because the propose survey overlaps with BIAs and critical habitat 
for some species (see MM Occurance), L-DEO will implement additional 
measures related to these areas including area avoidance and the 
implementation of special shutdown zones. For Steller sea lion 
rookeries and major haulouts, classified as critical habitat (58 FR 
45269, August 27, 1993). Steller sea lions maintain rookeries and major 
haulouts in the area of L-DEO's survey (Figure 1 in the IHA 
Application). Additionally the timing of the survey overlaps with the 
breeding season of Steller sea lions. As such, L-DEO must observe a 
three nautical mile exclusion zone around these critical habitats. This 
means that L-DEO avoid transiting through and operating seismic airguns 
in these areas.
    A portion of L-DEO's planned survey will also occur in the fin 
whale BIA (Ferguson et al. 2015). Because of the temporal and spatial 
overlap in the planned survey and peak use of the fin whale BIA, L-DEO 
will implement a shutdown if a fin whale or group of fin whales is 
observed at within a 1,500 m radius from the acoustic source, within 
their BIA. L-DEO will refer to Ferguson et al. (2015) for the location 
of the BIA, but waters around the Semidi Islands, Kodiak Island, and 
Chirikof Island generally define the portion of the BIA L-DEO is 
expected to transit through.
    The expected elevated density of North Pacific right whales in 
their critical habitat means that additional measures are prudent for 
this area. When transiting through North Pacific right whale critical 
habitat, any survey operations conducted by L-DEO must be done during 
daylight hours, to facilitate the ability of PSOs to observe any right 
whales that may be present. Additionally, if transit through the North 
Pacific right whale critical habitat is required during darkness or 
conditions of similar limited visibility, L-DEO must reduce vessel 
speed to at most 5 kn (knots) while in the critical habitat. These 
measures are in addition to the requirement that L-DEO must implement a 
shutdown if a North Pacific right whale is observed at any distance.

Mitigation for Subsistence Uses of Marine Mammals--Community Outreach

    Although impacts on subsistence uses are not expected due to the 
strong separation in time and space between marine mammal subsistence 
harvest and L-DEO's specified activities, project principle 
investigators will conduct outreach with communities near the planned 
project area to identify and avoid areas of potential conflict, 
including for marine subsistence activities. This measure will mitigate 
any potential negative impact on subsistence hunting activities, 
despite there being no expected significant impact.
    NMFS has determined that these mitigation measures provide the 
means of effecting the least practicable impact on the affected species 
or stocks and their habitat, paying particular attention to rookeries, 
mating grounds, and areas

[[Page 27264]]

of similar significance, and on the availability of such species or 
stock for subsistence uses.

Monitoring and Reporting

    In order to issue an IHA for an activity, Section 101(a)(5)(D) of 
the MMPA states that NMFS must set forth, requirements pertaining to 
the monitoring and reporting of such taking. The MMPA implementing 
regulations at 50 CFR 216.104 (a)(13) indicate that requests for 
authorizations must include the suggested means of accomplishing the 
necessary monitoring and reporting that will result in increased 
knowledge of the species and of the level of taking or impacts on 
populations of marine mammals that are expected to be present in the 
planned 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 six 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;

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     Vessel heading and speed at beginning and end of visual 
PSO duty shifts and upon any line change;
     Environmental conditions while on visual survey (at 
beginning and end of PSO shift and whenever conditions changed 
significantly), including BSS and any other relevant weather conditions 
including cloud cover, fog, sun glare, and overall visibility to the 
horizon;
     Factors that may have contributed to impaired observations 
during each PSO shift change or as needed as environmental conditions 
changed (e.g., vessel traffic, equipment malfunctions); and
     Survey activity information, such as acoustic source power 
output while in operation, number and volume of airguns operating in 
the array, tow depth of the array, and any other notes of significance 
(i.e., pre-clearance, ramp-up, shutdown, testing, shooting, ramp-up 
completion, end of operations, streamers, etc.).
    The following information should be recorded upon visual 
observation of any protected species:
     Watch status (sighting made by PSO on/off effort, 
opportunistic, crew, alternate vessel/platform);
     PSO who sighted the animal;
     Time of sighting;
     Vessel location at time of sighting;
     Water depth;
     Direction of vessel's travel (compass direction);
     Direction of animal's travel relative to the vessel;
     Pace of the animal;
     Estimated distance to the animal and its heading relative 
to vessel at initial sighting;
     Identification of the animal (e.g., genus/species, lowest 
possible taxonomic level, or unidentified) and the composition of the 
group if there is a mix of species;
     Estimated number of animals (high/low/best);
     Estimated number of animals by cohort (adults, yearlings, 
juveniles, calves, group composition, etc.);
     Description (as many distinguishing features as possible 
of each individual seen, including length, shape, color, pattern, scars 
or markings, shape and size of dorsal fin, shape of head, and blow 
characteristics);
     Detailed behavior observations (e.g., number of blows/
breaths, number of surfaces, breaching, spyhopping, diving, feeding, 
traveling; as explicit and detailed as possible; note any observed 
changes in behavior);
     Animal's closest point of approach (CPA) and/or closest 
distance from any element of the acoustic source;
     Platform activity at time of sighting (e.g., deploying, 
recovering, testing, shooting, data acquisition, other); and
     Description of any actions implemented in response to the 
sighting (e.g., delays, shutdown, ramp-up) and time and location of the 
action.
    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.
    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.

Reporting

    L-DEO will be required to shall 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 report will 
also include estimates of the number and nature of exposures that 
occurred above the harassment threshold based on PSO observations, 
including an estimate of those on the trackline but not detected. 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.

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

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preamble for NMFS's implementing regulations (54 FR 40338; September 
29, 1989), the impacts from other past and ongoing anthropogenic 
activities are incorporated into this analysis via their impacts on the 
environmental baseline (e.g., as reflected in the regulatory status of 
the species, population size and growth rate where known, ongoing 
sources of human-caused mortality, or ambient noise levels).
    To avoid repetition, our analysis applies to all species listed in 
Table 1, given that NMFS expects the anticipated effects of the planned 
seismic 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 measures. 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.
    The final IHA authorizes a limited number of instances of Level B 
harassment of 21 species of marine mammal, and a limited number of 
instances of take by Level A harassment for 13 of those 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 which, because of their comparatively short 
duration, are considered to be of lower severity and with no lasting 
biological consequences (e.g., Southall et al., 2007).
    Potential impacts to marine mammal habitat were discussed briefly 
in this document and more extensively in the proposed IHA (84 FR 14200, 
April 9, 2019) (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 
(~18 days) and temporary nature of the disturbance, the availability of 
similar habitat and resources in the surrounding area, the impacts to 
marine mammals and the food sources that they utilize are not expected 
to cause significant or long-term consequences for individual marine 
mammals or their populations.
    The tracklines of this survey either traverse or are proximal to 
the BIAs for four baleen whale species including fin, gray, North 
Pacific right, and humpback whales in U.S. waters of the Gulf of Alaska 
(Ferguson et al. 2015). Additionally, there is a BIA for beluga whales 
in nearby Cook Inlet, but the location of the BIA means the habitat 
will not co-occur with the effects of L-DEO's survey (Ferguson et al. 
2015). The North Pacific Right whale feeding BIA east of the Kodiak 
Archipelago is primarily used between June and September. The fin whale 
feeding BIA that stretches from Kenai Peninsula through the Alaska 
Peninsula is primarily used between June and August. The gray whale 
feeding BIA east of the Kodiak Archipelago is primarily used between 
June and August. For the North Pacific Right whale, gray whale, and fin 
whale feeding BIAs, L-DEO's survey planned for June 1 through June 19, 
2019 could overlap with a period where BIAs represent an important 
habitat. However, only of a portion of seismic survey days would 
actually occur in or near these BIAs, and all survey efforts should be 
completed by mid-June, still in the early window of primary use for all 
these BIAs. Additionally, there are mitigation measures in place that 
should further reduce take number and severity for fin whales and North 
Pacific right whales. These include the requirement to shutdown the 
acoustic source if a fin whale, within the fin whale BIA, is observed 
within 1,500 meters of the source and the requirement to shutdown if a 
North Pacific right whale is observed at any distance from the source. 
The gray whale migratory corridor BIA and humpback whale feeding BIAs 
overlap spatially with L-DEO's survey, but the timing of primary use of 
these BIAs does not overlap temporally with the survey. Gray whales are 
most commonly seen migratory northward between March and May and 
southward between November and January. As planned, there is no 
possibility that L-DEO's survey impacts the southern migration, and 
presence of northern migrating individuals should be below peak during 
survey operations beginning in June 2019. Additionally, humpback whale 
feeding BIAs in the region are primarily used between July and August 
or September. L-DEO's survey efforts should be completed before peak 
use of these feeding habitats. For all habitats, no physical impacts to 
BIA habitat are anticipated from seismic activities. While SPLs of 
sufficient strength have been known to cause injury to fish and fish 
and invertebrate mortality, in feeding habitats, the most likely impact 
to prey species from survey activities would be temporary avoidance of 
the affected area and any injury or mortality of prey species would be 
localized around the survey and not of a degree that would adversely 
impact marine mammal foraging. The duration of fish avoidance of a 
given area after survey effort stops is unknown, but a rapid return to 
normal recruitment, distribution and behavior is expected. Given the 
short operational seismic time near or traversing BIAs, as well as the 
ability of cetaceans and prey species to move away from acoustic 
sources, NMFS expects that there would be, at worst, minimal impacts to 
animals and habitat within the designated BIAs.
    Critical habitat has been designated for the ESA listed North 
Pacific right whale and western DPS of Steller sea lions. Only a 
portion of L-DEO's planned seismic survey will occur in these critical 
habitats. Steller sea lion critical habitat also includes a ``no 
approach'' zone within 3 nmi of rookeries for vessels. Steller sea 
lions both occupy rookeries and pup from late-May through early-July 
(NMFS 2008), which coincides with L-DEO's planned survey. Thus, we are 
requiring that the planned survey avoid transiting or surveying within 
3 nmi of any rookeries. For North Pacific right whale critical habitat, 
L-DEO would only need

[[Page 27267]]

to traverse approximately 35 km of the designated critical habitat. At 
a speed of approximately 9.3 km per hour (5 kn), L-DEO would only be in 
the critical habitat for less than 4 hours. L-DEO would only conduct 
survey activities in this critical habitat during daylight hours to 
facilitate the ability of PSOs to observe any right whales that may be 
present, so as to reduce the potential for their exposure to airgun 
noise. If they were in the critical habitat outside of daylight, vessel 
speed would be restricted to at most 5 kn. Additionally, L-DEO would be 
required to shutdown seismic airguns if a North Pacific right whale is 
observed at any distance, further minimizing the impacts on North 
Pacific right whales in their critical habitat and elsewhere. The 
characteristics that make this habitat an important feeding area for 
North Pacific right whales are abundant planktonic food sources. While 
there are possible impacts of seismic activity on plankton (McCauley et 
al., 2017), the currents that flow through the Gulf of Alaska will 
readily refresh plankton resources in the area. As such, this seismic 
activity is not expected to have a lasting physical impact on habitat 
or prey within it. Any impact would be a temporary increase in sound 
levels when the survey is occurring in or near the critical habitat and 
resulting temporary avoidance of prey or marine mammals themselves due 
to these elevated sound levels.
    After accounting for qualitative factors, the activity is expected 
to impact a small percentage of all marine mammal stocks that would be 
affected by L-DEO's planned survey (see ``Small Numbers'' below). 
Additionally, the acoustic ``footprint'' of the planned survey would be 
small relative to the ranges of the marine mammals that would 
potentially be affected. At any given time, sound levels would increase 
in the marine environment in a relatively small area surrounding the 
vessel compared to the range of the marine mammals within the planned 
survey area. The seismic array would be active 24 hours per day 
throughout the duration of the planned survey. However, the very brief 
overall duration of the planned survey (18 days) would further limit 
potential impacts that may occur as a result of the specified activity.
    The mitigation measures are expected to reduce the number and/or 
severity of takes by allowing for detection of marine mammals in the 
vicinity of the vessel by visual and acoustic observers, and by 
minimizing the severity of any potential exposures via 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 planned mitigation will be 
effective in preventing, at least to some extent, potential PTS in 
marine mammals that may otherwise occur in the absence of mitigation 
(although all authorized PTS has been accounted for in this analysis).
    NMFS concludes that exposures to marine mammal species and stocks 
due to L-DEO's 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 estimated and authorized take of marine mammals 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 specified activity is temporary and of relatively 
short duration (~18 days);
     The anticipated impacts of the specified activity on 
marine mammals would primarily be temporary behavioral changes due to 
avoidance of the area around the survey vessel;
     The number of instances of potential PTS that may occur 
are expected to be minimal. Instances of potential 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 mitigation measures, including visual and acoustic 
monitoring, power-downs, shutdowns, and enhanced measures for areas of 
biological importance are expected to minimize potential impacts to 
marine mammals (both amount and severity) in these important areas and 
times.
    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 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 Section 101(a)(5)(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.
    There are seven stocks for which the estimated instances of take 
appear high when compared to the stock abundance (Table 9), including 
the Northeast Pacific fin whale stock, the North Pacific right whale 
stock, the Western North Pacific gray whale stock, the Central North 
Pacific blue whale stock, the Central North Pacific humpback whale 
stock (Hawaii DPS), the Offshore killer whale stock, and the Gulf of 
Alaska, Aleutian Islands, and Bering Sea transient killer whale stock. 
However, when other qualitative factors are used to inform an 
assessment of the likely number of individual marine mammals taken, the 
resulting numbers are appropriately considered small. We discuss these 
in further detail below.
    For an additional three stocks (Alaska stocks of the three beaked 
whale species), there are no abundance estimates upon which to base a 
comparison. However, we note that the anticipated number of incidents 
of take by Level B and Level A harassment are low (46 to 196 for these 
three stocks) and represent a small number of animals within these 
stocks, which have extensive ranges across large parts of the North 
Pacific Ocean compared to L-DEO's planned survey area (Muto et al., 
2018). Based on the broad spatial distributions of these species 
relative to the planned survey area, NMFS concludes that the authorized 
take of these species represent small numbers relative to the affected 
species' overall

[[Page 27268]]

population sizes, though we are unable to quantify the authorized take 
numbers as a percentage of population.
    For all other stocks (aside from the seven referenced above and 
described below and the three beaked whales), the authorized take is 
less than 25 percent as compared to the stock abundance (recognizing 
that some of those takes may be repeats of the same individual, thus 
rendering the percentage even lower).
    The expected take of the Northeast Pacific stock of fin whales 
appears high when presented as a percentage of the available population 
estimate (123.5 percent), but this percentage is based on an occurrence 
estimate which surveyed only a small portion of the range (Rone et al. 
2017), and no representative estimate of the full stock abundance is 
available (Muto et al. 2018). The range of the Northeast Pacific fin 
whale stock extends through much of the north Pacific (Muto et al. 
2018). Based on the small portion of the stock's range that Rone et al. 
(2017) observed, the full stock abundance would be much higher than 
3,168 individuals, significantly reducing the percentage of the 
population that would be impacted by take from L-DEO's activities. 
Additionally, L-DEO's actions are located in a small portion of the 
total range and will occur within a short period of less than a month. 
L-DEO's previous marine mammal monitoring in the Gulf of Alaska 
reported 79 fin whales (RPS 2011) and Zerbini et al. (2006) observed 
530 fin whales across 3 years of summer surveys in the Northern Gulf of 
Alaska. Given these previous observations, it is not realistic that L-
DEO will encounter 3,914 individual fin whales. Instead, given the 
range of the species, the known underestimate of stock abundance, and 
the comparatively small action area, combined with the short duration 
of the survey, it is more likely that there will be multiple instances 
of take to a smaller number of individuals that are in the action area 
during the planned survey and entirely unlikely that more than a third 
of the stock would be exposed to the seismic survey.
    The estimated instances of take for North Pacific right whales 
appears high compared to stock abundance (35.5 percent), but 
realistically 11 right whales are not likely to experience harassment. 
Given the higher assumed density of whales in the critical habitat area 
off of Kodiak Island, the vast majority of estimated takes would occur 
in that area (see ``Take Calculation and Estimation''). Overall, right 
whales are very rarely detected in the Gulf of Alaska, and most 
evidence of the region's importance for the species is based on 
historic whaling records (Muto et al., 2018). Either visual or acoustic 
detections of a single right whale are rare in the Gulf of Alaska. 
North Pacific right whales are much more commonly detected in their 
Bering Sea critical habitat (73 FR 19000, April 8, 2008; Muto et al., 
2018). Given this evidence, only a small portion of the population is 
expected to be present in the Gulf of Alaska and the Kodiak Island 
critical habitat. As such, it is more realistic to believe there will 
be multiple takes of the few individuals present, comprising less than 
a third of the stock. Additionally, L-DEO planned survey will only 
impact the North Pacific right whale critical habitat for a very short 
portion of their survey and there are additional mitigation measures in 
place to further minimize any acoustic impacts on North Pacific right 
whales.
    The number of instances of take expected for the Western North 
Pacific stock (WNP) of gray whales appears high when compared to the 
stock abundance (1,247.43 percent). In reality, 2,183 individuals will 
be not experience take from this stock. There are two stocks of gray 
whales in this area, the WNP and the Eastern North Pacific stock (ENP). 
It is more realistic to apportion expected takes between these stocks. 
NMFS has no commonly used method to estimate the relative occurrence of 
these stocks, but here we apportion the takes between the two stocks 
using their relative abundances and a correction factor to ensure this 
number is conservative. The total abundance of the two stocks is 27,135 
gray whales. Based on estimates of stock size (Table 1), 0.65 percent 
of encountered gray whales would be expected to come from the WNP 
stock, and 99.35 percent would be expected to come from the ENP stock, 
which results in an apportioned take estimate for each stock of 14 
(WNP) and 2,169 (ENP). To represent uncertainty in this method and 
produce a conservative estimate, we then double the apportioned take 
for the smaller stocks, resulting in an estimated 28 takes for the WNP 
stock. This estimated level of take could impact an estimated 16 
percent of the WNP stock if each take occurred to a different 
individual. Further supporting this conclusion, the summer feeding 
grounds of WNP gray whales are believed to be off the Sakhalin Islands 
and other parts of coastal eastern Russia. In total, 27 to 30 whales 
have been observed in both the WNP and ENP, meaning that while some 
whales identified on these summer grounds have been observed 
overwintering in the eastern Pacific around North America, some also 
migrate to Japanese and Chinese waters (Caretta et al., 2014; Caretta 
et al., 2019 DRAFT). Based on relative abundance of gray whale stocks 
and knowledge of behavior, the WNP stock is expected to make up a small 
portion of the gray whales that will experience take from L-DEO's 
activity. Therefore, it is entirely unlikely that more than a third of 
the stock would be exposed to the seismic survey.
    The expected instances of take of the Central North Pacific (CNP) 
stock of blue whales appears high when compared to the abundance (37 
percent), however, in reality 50 CNP blue whales are not likely to be 
harassed. Blue whales belonging to the CNP stock appear to feed in 
summer in waters southwest of Kamchatka, south of the Aleutians, and in 
the Gulf of Alaska (Stafford 2003; Watkins et al. 2000). Because of 
this large summer range of CNP blue whales compared to the size of L-
DEO's action area, it is more likely that there will be multiple takes 
of a smaller number of individuals that would occur within the action 
area, and the percentage of the stock taken will be less than a third 
of the individuals.
    For humpback whales, takes are apportioned between the different 
stocks or DPSs present based on Wade et al. (2016). With this 
apportionment, the expected instances of take of the Central North 
Pacific stock's Hawaii DPS appears high (44.8 percent of the estimated 
DPS abundance). In reality, 5,101 Hawaii DPS humpback whales are not 
likely to be harassed, as it is more likely that a smaller number of 
individuals will experience multiple takes. The Gulf of Alaska is an 
important center of humpback whale abundance, and L-DEO's survey 
affects a portion of the Gulf of Alaska. The highest densities of 
humpback whales in the Gulf of Alaska are observed between July and 
August (Ferguson et al., 2015), while L-DEO's survey is planned for 
June, so the survey should not overlap with peak abundance. 
Additionally, there are other areas of high humpback whale density in 
the Aleutian Islands and Bering Sea (Muto et al. 2018). This evidence, 
plus the CNP stock's large range relative to L-DEO's action area, along 
with the short duration of the survey, mean that it is more likely that 
there will be multiple takes of a smaller portion of the individuals 
that occur in L-DEO's action area, and fewer than a third of the 
individuals in the stock will be taken.
    The expected instances of take from both the Offshore and Gulf of 
Alaska, Aleutian Islands, and Bering Sea

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transient stocks of killer whales appears high when compared against 
the stock abundance (245 percent and 100.2 percent respectively). In 
reality, 588 individuals will not experience take from each of these 
stocks. There are three stocks of killer whales in this area, including 
the Eastern North Pacific Alaska Resident stock, and it is more 
realistic to apportion expected takes between these stocks. NMFS has no 
commonly used method to estimate the relative occurrence of these 
stocks, but here we apportion the takes between the three stocks using 
their relative abundances and a correction factor to ensure this number 
is conservative. The total abundance of the three stocks in the area is 
3,174 killer whales. Based on estimates of stock size, 73.9 percent of 
encountered killer whales would be expected to come from the Alaska 
resident stock, 18.5 percent would be expected to come from the Gulf of 
Alaska, Aleutian Islands, and Bering Sea stock, and 7.6 percent would 
be expected to come from the offshore stock, which come to a take 
estimate for each stock of 434.8, 108.7 and 44.5 respectively. To 
represent uncertainty in this method and produce a conservative 
estimate, we then double the apportioned take for each of the smaller 
stocks, resulting in an estimated 218 takes for the Gulf of Alaska, 
Aleutian Islands, and Bering Sea stock and 90 takes for the Offshore 
stock. Comparing these estimates to their associated stock abundance 
estimates results in 37.1 percent of the Gulf of Alaska, Aleutian 
Islands, and Bering Sea stock experiencing take and 37.5 of the 
Offshore stock experiencing take. While these numbers still appear 
high, the extensive ranges of both stocks compared to L-DEO's action 
area, as well as the short duration of the survey, mean that 
realistically there will be multiple takes of a smaller portion of both 
killer whale stocks, resulting in no more than a third of the 
individuals of any of these stocks being taken. Individuals from the 
offshore stock are known to undertake large movements across their 
entire range, from the Aleutian Islands to the California coast and use 
numerous portions of this habitat in the spring and summer (Dahlheim et 
al. 2008). The Gulf of Alaska, Aleutian Islands, and Bering Sea 
transient stock occupies a range that includes all of the U.S. EEZ in 
Alaska (Muto et al. 2018), with L-DEO only impacting a portion of this 
range for a limited time period.
    Based on the analysis contained herein of the specified activity 
(including the 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

    In order to issue an IHA, NMFS must find that the specified 
activity will not have an ``unmitigable adverse impact'' on the 
subsistence uses of the affected marine mammal species or stocks by 
Alaskan Natives. NMFS has defined ``unmitigable adverse impact'' in 50 
CFR 216.103 as an impact resulting from the specified activity: (1) 
That is likely to reduce the availability of the species to a level 
insufficient for a harvest to meet subsistence needs by: (i) Causing 
the marine mammals to abandon or avoid hunting areas; (ii) Directly 
displacing subsistence users; or (iii) Placing physical barriers 
between the marine mammals and the subsistence hunters; and (2) That 
cannot be sufficiently mitigated by other measures to increase the 
availability of marine mammals to allow subsistence needs to be met.
    In the GOA, the marine mammals that are hunted are Steller sea 
lions and harbor seals. For seals, these harvests are traditionally low 
from May through August, when harbor seals are raising pups and 
molting. Sea lions are taken from Kodiak Island and other locations in 
the action area in low numbers year round, but harvests are minimal 
during late spring and summer (Wolfe et al. 2012).
    L-DEO's planned seismic survey would occur during a period of low 
harbor seal and Stellar sea lion harvest, so any impact on subsistence 
activities will be minimal. Additionally, the survey will occur for 
approximately 18 days, and the portion of the survey that would occur 
in nearshore waters, where pinniped harvest is most likely, would be 
even shorter. L-DEO has also conducted outreach related to subsistence 
users in the area, in order to determine if potential use conflicts 
existed and avoid these conflicts if possible. As described in the 
``Effects of Specified Activities on Subsistence Uses of Marine 
Mammals'' section above, L-DEO received no comment from the relevant 
organizations contacted, meaning no concerns were raised about the 
project. This outreach, in combination with mitigation measures to 
avoid Steller sea lion rookeries and haulouts, marine mammal 
monitoring, and establishing exclusion zones, will effectively minimize 
impacts on these marine mammals, as well as impacts on subsistence 
users.
    Based on the description of the specified activity, the measures 
described to minimize adverse effects on the availability of marine 
mammals for subsistence purposes, and the mitigation and monitoring 
measures, NMFS has determined that there will not be an unmitigable 
adverse impact on subsistence uses from L-DEO's specified activities.

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), NSF 
prepared an Environmental Assessment (EA) to consider the direct, 
indirect and cumulative effects to the human environment resulting from 
this marine geophysical survey in the Gulf of Alaska. NSF made its EA 
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. The comment ran 
concurrently with the publication of the proposed IHA, and was 
available on NSF's website (at https://www.nsf.gov/geo/oce/envcomp/) 
and was linked to within the proposed Federal Register Notice. Also in 
compliance with NEPA and the CEQ regulations, as well as NOAA 
Administrative Order 216-6, NMFS has reviewed the NSF's EA, determined 
it to be sufficient, and adopted that EA and signed a Finding of No 
Significant Impact (FONSI) on May 31, 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 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 Protected Resources Interagency Cooperation 
Division issued a Biological Opinion on May 31, 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

[[Page 27270]]

not likely to jeopardize the continued existence of blue whale, fin 
whale, gray whale (WNP DPS), humpback whale (Mexico DPS and Western 
North Pacific DPS), North Pacific right whale, sei whale, sperm whale, 
and Steller sea lion (Western DPS), and is not likely to destroy or 
adversely modify North Pacific right whale or western DPS Steller sea 
lion critical habitat or the critical habitat of other 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 21 marine mammal species incidental to a marine 
geophysical survey in the Gulf of Alaska, provided the previously 
mentioned mitigation, monitoring and reporting are incorporated.

    Dated: June 4, 2019.
Donna S. Wieting,
Director, Office of Protected Resources, National Marine Fisheries 
Service.
[FR Doc. 2019-12319 Filed 6-11-19; 8:45 am]
 BILLING CODE 3510-22-P