Takes of Marine Mammals Incidental to Specified Activities; Taking Marine Mammals Incidental to a Marine Geophysical Survey in the North Pacific Ocean, 44578-44603 [2018-19008]

Agencies

• DEPARTMENT OF COMMERCE
• National Oceanic and Atmospheric Administration

[Federal Register Volume 83, Number 170 (Friday, August 31, 2018)]
[Notices]
[Pages 44578-44603]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2018-19008]


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DEPARTMENT OF COMMERCE

National Oceanic and Atmospheric Administration

RIN 0648-XG144


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

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

[[Page 44579]]


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 take, by Level A and/or Level B harassment, marine mammals 
during a Marine Geophysical Survey in the North Pacific Ocean.

DATES: This Authorization is effective from September 1, 2018, through 
August 31, 2019.

FOR FURTHER INFORMATION CONTACT: Rob Pauline, 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.

Summary of Request

    On March 16, 2018, NMFS received a request from the L-DEO for an 
IHA to take marine mammals incidental to conducting a marine 
geophysical survey in the North Pacific Ocean. L-DEO submitted a 
revised application on June 11, 2018. On June 13, 2018, we deemed L-
DEO's application for authorization to be adequate and complete. L-
DEO's request is for take of small numbers of 39 species of marine 
mammals by Level A and Level B harassment. Underwater sound associated 
with airgun use may result in the behavioral harassment or auditory 
injury of marine mammals in the ensonified areas. Mortality is not an 
anticipated outcome of airgun surveys such as this, and, therefore, an 
IHA is appropriate.
    NMFS has issued an IHA to L-DEO authorizing the take of 39 species 
by Level A and Level B harassment. The IHA is effective from September 
1, 2018 through August 31, 2019.

Description of Planned Activity

    The planned activity consists of two high-energy seismic surveys 
conducted at different locations in the North Pacific Ocean. 
Researchers from L-DEO and University of Hawaii, with funding from the 
U.S. National Science Foundation (NSF), in collaboration with 
researchers from United States Geological Survey (USGS), Oxford 
University, and GEOMAR Helmholtz Centre for Ocean Research Kiel 
(GEOMAR), plan to conduct the surveys from the Research Vessel (R/V) 
Marcus G. Langseth (Langseth) in the North Pacific Ocean. The first 
planned seismic survey would occur in the vicinity of the Main Hawaiian 
Islands in 2018 and a subsequent survey would take place at the Emperor 
Seamounts in 2019. The planned timing for the Hawaii survey is late 
summer/early fall 2018; the timing for the Emperor Seamounts survey 
would likely be late spring/early summer 2019. Both surveys would use a 
36-airgun towed array with a total discharge volume of ~6,600 in\3\. 
The main goal of the surveys planned by L-DEO and the University of 
Hawaii is to gain fundamental insight into the formation and evaluation 
of Hawaiian-Emperor Seamount chain, and inform a more comprehensive 
assessment of geohazards for the Hawaiian Islands region.
    The Hawaii survey would be expected to last for 38 days, including 
~19 days of seismic operations, 11 days of equipment deployment/
retrieval, ~5 days of operational contingency time (e.g., weather 
delays, etc.), and ~3 days of transit. The Emperor Seamounts survey 
would be expected to last 40 days, including ~13 days of seismic 
operations, ~11 days of equipment deployment/retrieval, ~3 days of 
operational contingency time, and 13 days of transit.
    Representative survey tracklines are shown in Figures 1 and 2 in 
the application. Water depths in the Hawaii survey area range from ~700 
m to more than 5,000 m. The water depths in the Emperor Seamounts 
survey area range from 1,500-6,000 m. The Hawaii seismic survey will be 
conducted within the U.S. exclusive economic zone (EEZ); the Emperor 
Seamounts survey will take place in International Waters.
    The procedures to be used for the planned surveys would be similar 
to those used during previous seismic surveys by L-DEO and would use 
conventional seismic methodology. The surveys would involve one source 
vessel, the Langseth, which is owned by NSF and operated on its behalf 
by Columbia University's L-DEO. The Langseth would deploy an array of 
36 airguns as an energy source with a total volume of ~6,600 in\3\. The 
receiving system would consist of ocean bottom seismometers (OBSs) and 
a single hydrophone streamer 15 km in length. As the airgun arrays are 
towed along the survey lines, the hydrophone streamer would transfer 
the data to the on-board processing system, and the OBSs would receive 
and store the returning acoustic signals internally for later analysis.
    A detailed description of the planned project is provided in the 
Federal Register notice for the proposed IHA (83 FR 30480; June 28, 
2018). Since that time, no changes have been made to the planned 
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

    NMFS published a notice of proposed IHA in the Federal Register on 
June 28, 2018 (83 FR 30480). During the 30-day public comment period, 
NMFS received comments from the Marine Mammal Commission (Commission), 
the Marine Seismic Research Oversight Committee (MSROC), the Cascadia 
Research Consortium (CRC), the Natural Resources Defense Council (NRDC) 
and from members of the general public. NMFS has posted the comments 
online at: https://www.fisheries.noaa.gov/national/marine-mammal-
protection/incidental-take-authorizations-research-

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and-other-activities. The following is a summary of the public comments 
and NMFS' responses.
    Comment: The Commission noted that several of the density estimates 
used by NMFS were outdated or incorrect.
    Response: NMFS used several density sources to estimate take 
including Bradford et al. (2015, 2017) and methods described in 
Department of the Navy (2017). As the Commission recommended, for the 
final IHA notice, NMFS has revised the densities for striped dolphins 
to 25 from 5.36 animals/1,000 km\2\ and for Fraser's dolphins to 21 
from 4.17 animals/1,000 km\2\ based on Bradford (2017). In the proposed 
notice, NMFS divided by three the unidentified Mesoplodon spp. density 
of 1.89 animals/1,000 km\2\ from Bradford et al. (2017) (resulting in 
0.63 animals/1,000 km\2\) for gingko-toothed, Deraniyagala's, and 
Hubb's beaked whale densities. NMFS revised the density for each 
species in the notice to 1.89 animals/1,000 km\2\, since there was no 
data available identifying separate densities for these species. NMFS 
updated the false killer whale densities to animals/100 km\2\ as take 
had been incorrectly estimated using a density of animals/1,000 km\2\ 
in the notice of proposed IHA (Bradford et al. 2015). NMFS further 
indicated it would amend all takes accordingly. NMFS utilized an 
average group size from Bradford et al. (2017) to increase the number 
of recalculated Level B harassment takes of killer whales to five. NMFS 
also increased Level A harassment takes for humpback and sei whales to 
average group size.
    Comment: The Commission recommended that NMFS re-calculate the monk 
seal density based on an abundance of 1,324 from Baker et al. (2016) as 
this is thought to be the best available density information. The 
Commission also recommended that NMFS re-estimate the number of Level B 
harassment takes of monk seals based on this data.
    Response: NMFS has recalculated authorized Level B harassment takes 
based on the Commission's recommendation. A complete description may be 
found in the Estimated Take section.
    Comment: The Commission and NRDC expressed concerns about potential 
impacts to small and resident populations of marine mammals located in 
Main Hawaiian Islands. The Commission recommended that NMFS require L-
DEO to implement shut-down procedures if a melon-headed whale or group 
of melon-headed whales is observed in the habitat of the Kohala 
resident stock and ensure that the estimated number of Level B 
harassment takes is sufficient based on group size of melon-headed 
whales for the Hawaiian Islands stock. The Commission noted that 
similar issues exist for the various MHI insular stocks of spinner and 
common bottlenose dolphins. However, the group sizes for those species 
are much less than for melon- headed whales. The Commission recommended 
that NMFS (1) authorize only those numbers of Level B harassment takes 
of the various MHI insular stocks of spinner and bottlenose dolphins 
for which NMFS can make a small numbers determination and (2) if the 
authorized takes are met for any of those stocks, require L-DEO to 
implement shut-down procedures if a spinner or bottlenose dolphin or 
group of dolphins is observed approaching or within the Level B 
harassment zone in the habitat of the specific MHI insular stock.
    Response: L-DEO will be required to implement shut-down procedures 
if a melon-headed whale or group of melon-headed whales is observed in 
Kohala resident stock habitat. NMFS has also revised authorized take 
numbers to ensure that the number of estimated takes is sufficient 
based on group size of melon-headed whales for the Hawaiian Islands 
stock (see Take Calculation and Estimation section for detail). NMFS 
also has made small numbers determinations for the stocks described in 
the comment above and will require L-DEO to implement shut-down 
procedures if a spinner or bottlenose dolphin or group of dolphins is 
observed approaching or within the Level B harassment zone in the 
habitat of the specific MHI insular stock if the authorized takes are 
met for any of these stocks.
    Comment: The Commission noted that various datasets used for 
estimating densities in the area of the Emperor survey were compiled 30 
to 35 years ago while others originated from other geographic regions 
with presumed assumptions. The Commission had previously recommended 
that NMFS should adjust the density estimates used to estimate the 
numbers of potential takes by incorporating some measure of uncertainty 
when available density data originate from other geographical areas, 
temporal scales, and species. 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 
Emperor survey area. 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 when available density data 
originate from different geographic areas, temporal scales, and 
species, especially for actions which will occur outside the U.S. EEZ 
where site- and species-specific density estimates tend to be scant, 
such as L-DEO's planned survey in the Emperor Seamounts area. We have 
attempted to do so in this IHA, and feel the 25 percent correction 
factor is an appropriate method in this case to account for 
uncertainties in the density data that were available for use in the 
take estimates. NMFS is open to consideration of other correction 
factors for use 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 require L-DEO to 
specify why it is using radial distances for SELcum and SPLrms metrics 
and radii for SPLpeak metrics.
    Response: The radius is commonly used to determine Level A 
harassment isopleths, as well as those for Level B. In order for L-DEO 
to be able to account for accumulation associated with NMFS Revised 
Technical Guidance's SELcum thresholds, including the use of the NMFS 
optional User Spreadsheet tool, they needed to determine far-field 
source level. In order to do, L-DEO relied upon the more conservative 
radial distance, since the radial distance is larger than the radius. 
They used the radial distance to determine modified far-field source 
levels, which were directly incorporated in the NMFS optional User 
Spreadsheet to determine Level A isopleths using the SELcum metric. L-
DEO also used the more conservative radial distance to back calculate 
their modified far-field source levels for SPLpeak. The radius was then 
determined by plugging the radial

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distance into the Pythagorean theorem (as the hypotenuse). This radius 
value was then used to calculate the peak sound pressure level 
isopleth.
    In summary, use of the radius is not inconsistent with how 
isopleths have been calculated for other sources, including seismic 
activities. Use of the radius will also account for animals at depth 
that are at the longest radial distance. Note that the use of radial 
distance was used only to establish modified far-field source levels.
    Comment: The Commission recommended that NMFS provide justification 
for why it believes that L-DEO's use of the Nucleus source model, which 
does not provide data above 2.5 kHz, is appropriate for determining the 
extents of the Level A harassment zones for MF and HF cetaceans.
    Response: Experience and amplitude spectral density showed in the 
L-DEO application indicate that most of the energy output for Langseth-
type source is below 1 kHz, and so the error done by omitting higher 
frequencies will be fairly small. To evaluate the impact of the high 
frequencies (>1 KHz), L-DEO calculated amplitude spectral densities 
using information from the Langseth Gulf of Mexico calibration 
experiment (Tolstoy et al., 2009) and compared them to the results used 
in the L-DEO application (up to 3KHz). Scenario A is the one used in 
the L-DEO application (spectrum up to 3 KHz). Scenario B considers the 
same spectrum up to 10 KHz. The spectrum was obtained by upsampling the 
farfield signature obtained from the Nucleus modeling package. Scenario 
C considers the spectrum derived from the farfield signature obtained 
using the Nucleus modeling package from 1 Hz to ~200 Hz and L-DEO 
extended the spectrum with a realistic decay curve (-35dB/decade) from 
~200 Hz up to 10 kHz. The -35dB/decade decay curve is derived from the 
slope hydrophone data from the Gulf of Mexico study (Fig. 14 of Tolstoy 
et al., 2009). Because this decay curve boosts/increases the amplitudes 
between 200 Hz and 1 KHz much more than the predicted spectrum derived 
from the Nucleus modeling package and that is valid in that frequency 
range, for scenario D, L-DEO took a -30dB/decade decay curve around 
~600 Hz.
    Results show that the adjustment factors slightly decrease for 
scenarios C and D and the corresponding PTS SELcum Isopleths to 
thresholds are a little higher for those two scenarios (<20m) but are 
always smaller than the PTS SELcum Isopleths to thresholds derived from 
the Peak SPL that was used here.
    Comment: The Commission recommended that NMFS require L-DEO to re-
estimate the proposed Level A and 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 (83 FR 30480; June 28, 2018) 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 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 smaller, 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; 3280.8 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

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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.
    LDEO has conveyed to NMFS that additional modeling efforts to 
refine the process and conduct comparative analysis may be possible 
with the availability of research funds and other resources. Obtaining 
research funds is typically accomplished through a competitive process, 
including those submitted to U.S. Federal agencies. 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 adequate for prediction of 
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. 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.
    L-DEO has met with the Commission and NMFS on several occasions to 
explain the model and why it is, although conservative, the most 
appropriate approach to use for R/V Langseth operations. The planned 
survey will mainly occur in deep water (98.5%) and as demonstrated in 
Diebold et al. 2010 and Tolstoy et al. 2009 for deep water, the results 
show that the predicted distances were conservative relative to 
measured values. Even allowing for scaling of actual measurements 
between different tow depths of Tolstoy (2009) from 6 m to 12 m in the 
IHA, this yields a radius of 4,940 which is much less than model 
predictions of 6,733 m included in the IHA application.
    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 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 directly on the trackline 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 but we believe that the Commission's 
described method needs further consideration in

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relation to the observations conducted during marine geophysical 
surveys. Therefore, at this time we do not prescribe a particular 
method for accomplishing this task. We look forward to engaging further 
both L-DEO, the Commission and other applicants to reach a 
determination on the most suitable method to for estimating g(0) and 
f(0) values.
    Comment: The Commission and NRDC recommended that NMFS refrain from 
implementing its proposed one-year renewal process and instead use 
abbreviated Federal Register notices and reference existing documents 
to streamline the incidental harassment authorization process. The 
Commission further recommends that NMFS provide the Commission and the 
public with a legal analysis supporting its conclusion that the process 
is consistent with the requirements under section 101(a)(5)(D) of the 
MMPA. Furthermore, if NMFS decides to bypass the notice and comment 
process in advance of issuing a renewal, it should nevertheless publish 
notice in the Federal Register whenever such a renewal has been issued.
    Response: NMFS appreciates the streamlining achieved by the use of 
abbreviated FR notices and intends to continue using them for proposed 
IHAs that include minor changes from previously issued IHAs, but which 
do not satisfy the renewal requirements. 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 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. NMFS has, however, modified the language for future proposed IHAs 
to clarify that all IHAs, including renewal IHAs, are valid for no more 
than one year and that the agency would consider only one renewal for a 
project at this time. In addition, notice of issuance or denial of a 
renewal IHA would be published in the Federal Register, as they are for 
all IHAs. Last, NMFS will publish on our website a description of the 
renewal process before any renewal is issued utilizing the new process.
    Comment: The Commission recommends that NMFS require earlier 
submission of applications and other documentation so that it has 
adequate time to review and provide comments on the adequacy and 
accuracy of the application, allow applicants to make necessary 
revisions or additions to the application, draft its proposed 
authorization, and consider the comments received from the public.
    Response: There are no regulations stipulating a required time 
frame for submission of an IHA applications in advance of the requested 
date of issuance. However, NMFS has provided to the public recommended 
time frames for submission of applications for IHAs and rulemakings/
letter of authorization (LOAs) which are posted at https://www.fisheries.noaa.gov/node/23111. NMFS will continue to strongly 
encourage applicants to submit applications well in advance of the 
anticipated issuance dates such that applications can undergo thorough 
review and revisions can be made as appropriate.
    Comment: The planned survey will pass through the ranges of a 
number of small island-associated populations around the main Hawaiian 
Islands. These include the range of the endangered Kohala resident 
stock of melon-headed whales and the newly designated critical habitat 
area for the Main Hawaiian Islands insular false killer whale Distinct 
Population Segment (83 FR 35062; July 24, 2018). Given that visual 
observation at night will be ineffective at detecting animals of either 
species, CRC recommended that seismic surveys through ranges of these 
species should only be allowed during daylight hours.
    Response: L-DEO has agreed to attempt to time their surveys such 
that most of the seismic activity would occur within the ranges of the 
two species of concern only during daylight hours. However, unforeseen 
circumstances (e.g. weather, equipment breakdown) may preclude L-DEO 
from conducting all seismic operations during daylight within these 
species' ranges. Various operational requirements and protocols 
associated with marine seismic surveys do not generally allow for the 
prolonged stoppage or delay of seismic activities when a trackline is 
being surveyed. Additionally, it will take the Langseth approximately 
10.6 hours per pass along Trackline 1 to traverse the stock boundaries 
of the Kohala resident stock. There will be two passes along both 
Tracklines 1 and 2 with each pass separated by several days. It will 
take the Langseth about 18.6 hours per pass on Trackline 1 and 12.5 
hours per pass onTrackline 2 to traverse the larger insular false 
killer whale critical habitat area. The amount of time spent within the 
identified boundary areas will be limited and the majority of 
monitoring will occur during daylight hours.
    Comment: CRC and a single individual both recommended that NMFS 
require additional monitoring of the melon-headed whale population 
during Trackline 1 of the seismic survey. This could be achieved by 
deploying satellite tags on individual melon-headed whales immediately 
(i.e., within a few days) prior to the survey vessel undertaking 
Trackline 1. The proximity of one or more groups of melon-headed whales 
to survey activities could be monitored. CRC recommended that NMFS 
should either require L-DEO to implement this type of monitoring 
program themselves or notify independent researchers who are permitted 
to work in the area during the timing of the survey with enough advance 
notice to allow for satellite tag monitoring.
    Response: NMFS generally does not require applicants to implement 
highly technical monitoring regimes, especially when the applicant 
would need to secure additional research permits. Furthermore, NMFS 
cannot direct an applicant to divulge what they deem to be highly 
sensitive information (i.e., ship location and/or route). Instead, NMFS 
encouraged CRC to contact L-DEO directly. Also, as noted above, the 
time spent in the vicinity of the small resident population of melon-
headed whale will be minimal.
    Comment: MSROC noted the scientific and societal importance of the 
planned Langseth seismic surveys, endorsed these collaborative research 
programs, and strongly encouraged NMFS to approve and issue an IHA. 
They urged NMFS to issue the IHA as soon as possible following the 
close of the public comment period.
    Response: NMFS appreciates the importance of this research and has 
issued the IHA to L-DEO in a timely manner.
    Comment: An individual referred to recent research findings 
(McCauley et al. 2017) indicating that use of airgun arrays may damage 
a range of invertebrates. The individual also felt that NOAA has the 
capacity & obligation to substantiate these claims prior to issuing any 
further permits.
    Response: Relatively little research has been focused on assessing 
the impacts of airguns on invertebrates. The study by McCauley et al. 
(2017) found that exposure to airgun sound decreased zooplankton 
abundance compared to control samples, and caused a two- to three-fold 
increase in adult and larval zooplankton mortality. They observed 
impacts on the zooplankton as far as 1.2

[[Page 44584]]

km from the exposure location--a much greater impact range than 
previously thought; however, there was no consistent decline in the 
proportion of dead zooplankton as distance increased and received 
levels decreased. The authors also stated that in order to have 
significant impacts on r-selected species such as plankton, the spatial 
or temporal scale of impact must be large in comparison with the 
ecosystem concerned, and it is possible that the findings reflect 
avoidance by zooplankton rather than mortality (McCauley et al., 2017). 
In addition, the results of this study are inconsistent with a large 
body of research that generally finds limited spatial and temporal 
impacts to zooplankton as a result of exposure to airgun noise (e.g., 
Dalen and Knutsen, 1987; Payne, 2004; Stanley et al., 2011).
    A modeling exercise was conducted as a follow-up to the McCauley et 
al. (2017) study (as recommended by McCauley et al. (2017)), in order 
to assess the potential for impacts on ocean ecosystem dynamics and 
zooplankton population dynamics (Richardson et al., 2017). Richardson 
et al. (2017) found that for copepods with a short life cycle in a 
high-energy environment, a full-scale airgun survey would impact 
copepod abundance up to three days following the end of the survey, 
suggesting that effects such as those found by McCauley et al. (2017) 
would not be expected to be detectable downstream of the survey areas, 
either spatially or temporally. However, these findings are relevant 
for zooplankton with rapid reproductive cycles in areas where there is 
a high natural replenishment rate resulting from new water masses 
moving in, and the findings may not apply in lower-energy environments 
or for zooplankton with longer life-cycles. In fact, the study found 
that by turning off the current, as may reflect lower-energy 
environments, the time to recovery for the modelled population extended 
from several days to several weeks.
    In the absence of further validation of the McCauley et al. (2017) 
findings, if we assume a worst-case likelihood of severe impacts to 
zooplankton within approximately 1 km of the acoustic source, the large 
spatial scale and wide dispersal of tracklines does not lead us to 
expect any meaningful follow-on effects to the prey base for marine 
mammals predators. While the large scale of effect observed by McCauley 
et al. (2017) may be of concern, especially in a more temperate 
environment, NMFS concludes that these findings indicate a need for 
more study, particularly where repeated noise exposure is expected--a 
condition unlikely to occur in relation to these planned surveys

Description of Marine Mammals in the Area of the Specified Activity

    Section 4 of the IHA application summarizes available information 
regarding status and trends, distribution and habitat preferences, and 
behavior and life history of the potentially affected species. More 
general information about these species (e.g., physical and behavioral 
descriptions) may be found on NMFS' website (https://www.fisheries.noaa.gov/find-species). Table 1 lists all species with 
expected potential for occurrence in the North Pacific Ocean and 
summarizes information related to the population, including regulatory 
status under the MMPA and ESA. Some of the populations of marine 
mammals considered in this document occur within the U.S. EEZ and are 
therefore assigned to stocks and are assessed in NMFS' Stock Assessment 
Reports (https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessments). As such, information on 
potential biological removal (PBR; 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) and on annual levels of 
serious injury and mortality from anthropogenic sources are not 
available for these marine mammal populations.
    Twenty-eight cetacean species, including 21 odontocetes (dolphins 
and small- and large-toothed whales) and seven mysticetes (baleen 
whales), and one pinniped species, could occur in the planned Hawaii 
survey area (Table 4). In the Emperor Seamounts survey area, 27 marine 
mammal species could occur, including 15 odontocetes (dolphins and 
small- and large-toothed whales), eight mysticetes (baleen whales), and 
four pinniped species. Some species occur in both locations. In total, 
39 species are expected to occur in the vicinity of the specified 
activity.
    Marine mammal abundance estimates presented in this document 
represent the total number of individuals estimated within a particular 
study or survey area. All values presented in Table 1 are the most 
recent available at the time of publication.

                                              Table 1--Marine Mammals That Could Occur in the Survey Areas
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                        Stock abundance                            Present at time of
                                                                           ESA/MMPA     (CV, Nmin, most                               survey (Y/N)
          Common name              Scientific name          Stock           status;     recent abundance     PBR     Annual M/ -------------------------
                                                                         strategic (Y/    survey) \2\                   SI3                    Emperor
                                                                            N) \1\                                                   HI       seamounts
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                           Order Cetartiodactyla-Cetacea-Superfamily Mysticeti (baleen whales)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Family Eschrichtiidae:
    Gray whale.................  Eschrichtius        Western North       E/D; Y        140 (0.04, 135,         0.06        unk           N            Y
                                  robustus.           Pacific.                          2011) \4\.
Family Balaenidae:
    North Pacific right whale..  Eubalaena japonica  Eastern North       E/D; Y        31 (0.226, 26,           N/A          0           N            Y
                                                      Pacific.                          2013) \6\.
                                                     N/A...............  ............  450 \5\..........  .........  .........  ...........  ...........
Family Balaenopteridae
 (rorquals):
    Humpback whale.............  Megaptera           Central North       -/-; N        10,103 (0.03,             83         25           Y            Y
                                  novaeangliae.       Pacific.                          7,890, 2006) \6\.
                                                     Western North       E/D; Y        1,107 (0.30, 865,          3        3.2  ...........  ...........
                                                      Pacific.                          2006) \6\.
    Minke whale................  Balaenoptera        Hawaii............  ............  UNK..............  .........  .........           N            Y
                                  acutorostrata.
                                                     N/A...............  ............  22,000 \7\.......  .........  .........  ...........  ...........
    Bryde's whale..............  Balaenoptera edeni/ Hawaii............  -/-; N        1,751 (0.29,            13.8          0           Y            Y
                                  brydei.                                               1,378, 2010)
                                                                                        \17\.
                                                     Eastern Tropical    -/-; N        UNK..............        UND        UNK  ...........  ...........
                                                      Pacific.
    Sei whale..................  Balaenoptera        Hawaii............  E/D; Y        178 (0.9, 93,            0.2        0.2           Y            Y
                                  borealis.                                             2010) \4\.
    Fin whale..................  Balaenoptera        Hawaii............  E/D; Y        154 (1.05, 75,           0.1          0           Y            Y
                                  physalus physalus.                                    2010) \17\.
                                                     N/A...............  ............  13,620-18,680 \9\  .........  .........  ...........  ...........
    Blue whale.................  Balaenoptera        Central North       E/D; Y        133 (1.09, 63,           0.1          0           Y            Y
                                  musculus musculus.  Pacific.                          2010) \17\.
--------------------------------------------------------------------------------------------------------------------------------------------------------

[[Page 44585]]

 
                                              Superfamily Odontoceti (toothed whales, dolphins, porpoises)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Family Physeteridae:
    Sperm whale................  Physeter            Hawaii............  E/D; Y        4,559 (0.33,            13.9        0.7           Y            Y
                                  macrocephalus.                                        3,478, 2010)
                                                                                        \17\.
                                                     N/A...............  N/A           29,674 \10\-       .........  .........  ...........  ...........
                                                                                        26,300 \11\.
Family Kogiidae:
    Pygmy sperm whale..........  Kogia breviceps...  Hawaii............  -/-; N        7,138 \4\........        UND          0           Y            Y
    Dwarf sperm whale..........  Kogia sima........  Hawaii............  -/-; N        17,519 \4\.......        UND          0           Y            Y
Family Ziphiidae (beaked
 whales):
    Cuvier's beaked whale......  Ziphius             Hawaii............  -/-; N        723 (0.69, 428,          4.3          0           Y            Y
                                  cavirostris.                                          2010) \17\.
                                                     N/A...............  ............  20,000 \12\......  .........  .........  ...........  ...........
    Longman's beaked whale.....  Indopacetus         Hawaii............  -/-; N        7,619 (0.66,              46          0           y            N
                                  pacificus.                                            4,592, 2010)
                                                                                        \17\.
    Blainville's beaked whale..  Mesoplodon          Hawaii............  -/-; N        2,105 (1.13,1,            10          0           Y            N
                                  densirostris.                                         980, 2010) \17\.
    Stejneger's beaked whale...  Mesoplodon          Alaska............  N             UNK..............        UND          0           N            Y
                                  stejnegeri.
    Ginkgo-toothed beaked whale  Mesoplodon          N/A...............  ............  25,300 \12\......  .........  .........        Rare       Absent
                                  ginkgodens.
    Deraniyagala's beaked whale  Mesoplodon hotaula  N/A...............  ............  25,300 \12\......  .........  .........           Y            N
    Hubb's beaked whale........  Mesoplodon          N/A...............  ............  25,300 \12\......  .........  .........           Y            N
                                  carlhubbsi.
    Baird's beaked whale.......  Berardius bairdii.  N/A...............  ............  10,190 \13\......  .........  .........           N            Y
Family Delphinidae:
    Rough-toothed dolphin......  Steno bredanensis.  Hawaii............  -/-; N        72,528 (0.39,             46        UNK            Common      N
                                                                                        52,033, 2010)
                                                                                        \17\.
    Common bottlenose dolphin..  Tursiops truncatus  Hawaii Pelagic....  -/-; N        21,815 (0.57,            140        0.2            Common      N
                                                                                        13,957, 2010)
                                                                                        \17\.
                                                     Kaua'i and Ni'ihau  -/-; N        184 (0.11, 168,          1.7        unk            Common      N
                                                                                        2005) \4\.
                                                     O'ahu.............  -/-; N        743 (0.54, 485,          4.9        unk            Common      N
                                                                                        2006) \4\.
                                                     4 Islands Region..  -/-; N        191 (0.24, 156,          unk        unk            Common      N
                                                                                        2006).
                                                     Hawaii Island.....  -/-; N        128 (0.13, 115,          1.6        unk            Common      N
                                                                                        2006) \4\.
    Common dolphin.............  Delphinus delphis.  N/A...............  ............  2,963,000 \14\...  .........  .........           N            Y
    Pantropical spotted dolphin  Stenella attenuata  Hawaii Pelagic....  -/-; N        55,795 (0.40,            403          0           Y            N
                                                                                        40,338, 2010)
                                                                                        \17\.
                                                     O'ahu.............  -/-; N        unk..............        unk        unk  ...........  ...........
                                                     4 Island Region...  -/-; N        unk..............        unk        unk  ...........  ...........
                                                     Hawaii Island.....  -/-; N        unk..............        unk      >=0.2  ...........  ...........
    Spinner dolphin............  Stenella            Hawaii Pelagic....  -/-; N        unk..............        unk        unk           Y            N
                                  longirostris.
                                                     Hawaii Island.....  -/-; N        631 (0.04, 585,          5.9        unk            Common      N
                                                                                        2013) \4\.
                                                     Oahu/4-Islands....  -/-; N        355 (0.09, 329,          3.3        unk           Y            N
                                                                                        2013) \4\.
    Striped dolphin............  Stenella            Hawaii............  -/-; N        61,021 (0.38,            449        unk           Y            Y
                                  coeruleoalba.                                         44,922, 2010)
                                                                                        \17\.
                                                     N/A...............  ............  964,362 \15\.....  .........  .........  ...........  ...........
    Fraser's dolphin...........  Lagenodelphis       Hawaii............  -/-; N        51,491 (0.66,            310          0           Y            N
                                  hosei.                                                31,034, 2010)
                                                                                        \17\.
    Pacific white-sided dolphin  Lagenorhynchus      Central North       ............  988,333 \16\.....  .........  .........           N            Y
                                  obliquidens.        Pacific.
    Northern right whale         Lissodelphis        N/A...............  ............  307,784 \16\.....  .........  .........           N            Y
     dolphin.                     borealis.
    Risso's dolphin............  Grampus griseus...  Hawaii............  -/-; N        11,613 (0.39,             82          0           Y            Y
                                                                                        8,210, 2010)
                                                                                        \17\.
                                                     N/A/..............  ............  110,457 \15\.....  .........  .........  ...........  ...........
    Melon-headed whale.........  Peponocephala       Hawaii............  -/-; N        8,666 (1.00,              43          0           Y            N
                                  electra.                                              4,299, 2010)
                                                                                        \17\.
                                                     Kohala Resident...  -/-; N        447 (0.12, 404,            4          0  ...........  ...........
                                                                                        2009) \4\.
    Pygmy killer whale.........  Feresa attenuata..  Hawaii............  -/-; N        10,640 (0.53,             56        1.1           Y            N
                                                                                        6,998, 2010)
                                                                                        \17\.
    False killer whale.........  Pseudorca           Hawaii Insular....  E/D;Y         167 (0.14, 149,          0.3          0           Y            Y
                                  crassidens.                                           2015) \17\.
                                                     Northwest Hawaiian  -/-; N        617 (1.11, 290,          2.3        0.4  ...........  ...........
                                                      Islands.                          2010) \17\.
                                                     Hawaii Pelagic....  -/-; N        1,540 (0.66, 928,        9.3        7.6  ...........  ...........
                                                                                        2010) \17\.
                                                     N/A...............  ............  16,668 \18\......  .........  .........  ...........  ...........
    Killer whale...............  Orcinus orca......  Hawaii............  -/-; N        146 (0.96, 74,           0.7          0           Y            Y
                                                                                        2010).
                                                     N/A...............  ............  8,500 \19\.......  .........  .........  ...........  ...........
    Short-finned pilot whale...  Globicephala        Hawaii............  -/-; N        19,503 (0.49,            106        0.9           Y            Y
                                  macrorhynchus.                                        13,197, 2010).
                                                     N/A...............  ............  53,608 \16\......  .........  .........  ...........  ...........
Family Phoenidae (porpoises):
    Dall's porpoise............  Phocoenoides dalli  N/A...............  ............  1,186,000 \20\...  .........  .........           N            Y
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                         Order Carnivora--Superfamily Pinnipedia
--------------------------------------------------------------------------------------------------------------------------------------------------------
Family Otariidae (eared seals
 and sea lions):
    Steller sea lion...........  Eumetopias jubatus  Western DPS.......  E/D; Y        50,983 (-,50,983,  .........  .........           N            Y
                                                                                        2015).
    Northern fur seal..........  Callorhinus         Eastern Pacific...  -/D; Y        626,734 (0.2,         11,405        437           N            Y
                                  ursinus.                                              530,474, 2014).
                                                     N/A...............  ............  1,100,000 \5\....  .........  .........  ...........  ...........
Family Phocidae (earless
 seals):
    Hawaiian monk seal.........  Neomonachus         Hawaii............  E/D; Y        1,324 (0.03,             4.4      >=1.6           Y            N
                                  schauinslandi.                                        1,261, 2015)
                                                                                        \17\.
    Northern elephant seal.....  Mirounga            ..................  ............  210,000-239,000    .........  .........           N            Y
                                  angustirostris.                                       \21\.
    Ribbon seal................  Histriophoca        Alaska............  -/-; N        184,000 (0.12,         9,785        3.8           N            Y
                                  fasciata.                                             163,000, 2013).
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ Endangered Species Act (ESA) status: Endangered (E), Threatened (T)/MMPA status: Depleted (D). A dash (-) indicates that the species is not listed
  under the ESA or designated as depleted under the MMPA. Under the MMPA, a strategic stock is one for which the level of direct human-caused mortality
  exceeds PBR or which is determined to be declining and likely to be listed under the ESA within the foreseeable future. Any species or stock listed
  under the ESA is automatically designated under the MMPA as depleted and as a strategic stock.

[[Page 44586]]

 
\2\ NMFS marine mammal stock assessment reports online at: www.nmfs.noaa.gov/pr/sars/. CV is coefficient of variation; Nmin is the minimum estimate of
  stock abundance.
\3\ These values, found in NMFS's SARs, represent annual levels of human-caused mortality plus serious injury from all sources combined (e.g.,
  commercial fisheries, ship strike). Annual M/SI often cannot be determined precisely and is in some cases presented as a minimum value or range. A CV
  associated with estimated mortality due to commercial fisheries is presented in some cases.
\4\ Carretta et al. 2017.
\5\ Jefferson et al. 2015.
\6\ Muto et al. 2017.
\7\ IWC 2018.
\8\ Central and Eastern North Pacific (Hakamada and Matsuoka 2015a).
\9\ Ohsumi and Wada, 1974.
\10\ Whitehead 2002.
\11\ Barlow and Taylor 2005.
\12\ Wade and Gerrodette 1993.
\13\ Western Pacific Ocean (Okamura et al. 2012).
\14\ ETP (Gerrodette and Forcada 2002 in Hammond et al. 2008b).
\15\ Gerrodette et al. 2008.
\16\ North Pacific (Miyashita 1993b).
\17\ Carretta et al. 2018.
\18\ Western North Pacific (Miyashita 1993a).
\19\ Ford 2009.
\20\ Buckland et al. 1993.
\21\ Lowry et al. 2014.
Note:--Italicized species are not expected to be taken or authorized for take.

    All species that could potentially occur in the planned survey area 
are included in Table 1. With the exception of Steller sea lions, these 
species or stocks temporally and spatially co-occur with the activity 
to the degree that take is reasonably likely to occur. However, the 
temporal and/or spatial occurrence of Steller sea lions is such that 
take is not expected to occur, and they are not discussed further 
beyond the explanation provided here. The Steller sea lion occurs along 
the North Pacific Rim from northern Japan to California (Loughlin et 
al. 1984). They are distributed around the coasts to the outer shelf 
from northern Japan through the Kuril Islands and Okhotsk Sea, through 
the Aleutian Islands, central Bering Sea, southern Alaska, and south to 
California (NMFS 2016c). There is little information available on at-
sea occurrence of Steller sea lions in the northwestern Pacific Ocean. 
The Emperor Seamounts survey area is roughly 1,200 kilometers away from 
the Aleutian Islands in waters 2,000 to more than 5,000 meters deep. 
Steller sea lions are unlikely to occur in the offshore survey area 
based on their known distributional range and habitat preference. 
Therefore, it is extremely unlikely that Steller sea lions would be 
exposed to the stressors associated with seismic activities and will 
not be discussed further.
    A detailed description of the of the species likely to be affected 
by the planned project, 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 (83 FR 30480; June 28, 2018); 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 (www.nmfs.noaa.gov/pr/species/mammals/) for 
generalized species accounts.

Potential Effects of Specified Activities on Marine Mammals and Their 
Habitat

    The effects of underwater noise from marine geophysical survey 
activities have the potential to result in behavioral harassment and, 
in a limited number of instances, auditory injury (PTS) of marine 
mammals in the vicinity of the action area. The Federal Register notice 
of proposed IHA (83 FR 30480; June 28, 2018) included a discussion of 
the effects of anthropogenic noise on marine mammals and their habitat, 
therefore that information is not repeated here; please refer to that 
Federal Register notice for that information. No instances of serious 
injury or mortality are expected as a result of L-DEO's survey 
activities.

Estimated Take

    This section provides an estimate of the number of incidental takes 
authorized through this IHA, which will inform both NMFS' consideration 
of whether the number of takes is ``small'' and the negligible impact 
determination. As described in detail below, modifications have been 
made to several take estimates based on recommendations from the public 
regarding density or occurrence of certain marine mammal species or 
stocks.
    Harassment is the only type of take expected to result from these 
activities. Except with respect to certain activities not pertinent 
here, section 3(18) of the MMPA defines ``harassment'' as: any act of 
pursuit, torment, or annoyance which (i) has the potential to injure a 
marine mammal or marine mammal stock in the wild (Level A harassment); 
or (ii) has the potential to disturb a marine mammal or marine mammal 
stock in the wild by causing disruption of behavioral patterns, 
including, but not limited to, migration, breathing, nursing, breeding, 
feeding, or sheltering (Level B harassment).
    Authorized takes would primarily be by Level B harassment, as use 
of seismic airguns has the potential to result in disruption of 
behavioral patterns for individual marine mammals. There is also some 
potential for auditory injury (Level A harassment) for mysticetes and 
high frequency cetaceans (i.e., kogiidae spp.), due to larger predicted 
auditory injury zones for those functional hearing groups. The required 
mitigation and monitoring measures are expected to minimize the 
severity of such taking to the extent practicable.
    Auditory injury is unlikely to occur for mid-frequency species 
given very small modeled zones of injury for those species (13.6 m). 
Moreover, the source level of the array is a theoretical definition 
assuming a point source and measurement in the far-field of the source 
(MacGillivray, 2006). As described by Caldwell and Dragoset (2000), an 
array is not a point source, but one that spans a small area. In the 
far-field, individual elements in arrays will effectively work as one 
source because individual pressure peaks will have coalesced into one 
relatively broad pulse. The array can then be considered a ``point 
source.'' For distances within the near-field, i.e., approximately 2-3 
times the array dimensions, pressure peaks from individual elements do 
not arrive simultaneously because the observation point is not 
equidistant from each element. The effect is destructive interference 
of the outputs of each element, so that peak pressures in the near-
field will be significantly lower than the output of the largest 
individual element. Here, the 230 dB peak isopleth distances would in 
all cases be expected to be within the near-field of the array where 
the definition of source level breaks down. Therefore, actual locations 
within this distance of the array center where the sound level exceeds 
230 dB peak SPL would not necessarily exist. In general, Caldwell and 
Dragoset (2000) suggest that the

[[Page 44587]]

near-field for airgun arrays is considered to extend out to 
approximately 250 m.
    As described previously, no mortality is anticipated or authorized 
for this activity. Below we describe how the take is estimated.
    Described in the most basic way, we estimate take by considering: 
(1) Acoustic thresholds above which NMFS believes the best available 
science indicates marine mammals will be 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. Below, we describe these 
components in more detail and present the exposure estimate and 
associated numbers of authorized takes.

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 the best available science 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 to fall under Level B 
harassment when exposed to underwater anthropogenic noise above 
received levels of 160 dB re 1 [mu]Pa (rms) for non-explosive impulsive 
(e.g., seismic airguns) sources. L-DEO's 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 (NMFS, 2016) identifies dual criteria to assess auditory 
injury (Level A harassment) to five different marine mammal groups 
(based on hearing sensitivity) as a result of exposure to noise from 
two different types of sources (impulsive or non-impulsive). The 
Technical Guidance identifies the received levels, or thresholds, above 
which individual marine mammals are predicted to experience changes in 
their hearing sensitivity for all underwater anthropogenic sound 
sources, reflects the best available science, and better predicts the 
potential for auditory injury than does NMFS' historical criteria.
    These thresholds were developed by compiling and synthesizing the 
best available science and soliciting input multiple times from both 
the public and peer reviewers to inform the final product, and are 
provided in Table 2 below. The references, analysis, and methodology 
used in the development of the thresholds are described in NMFS 2016 
Technical Guidance. As described above, L-DEO's activity includes the 
use of intermittent and impulsive seismic sources.

 Table 2--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 estimating the area ensonified above the 
relevant acoustic thresholds.
    The surveys will 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 (approximately 
1,600 m), intermediate water depth on the slope (approximately 600-
1,100 m), and shallow water (approximately 50 m) in the Gulf of Mexico 
in 2007-2008 (Tolstoy et al. 2009; Diebold et al. 2010).
    For deep and intermediate-water cases, the field measurements 
cannot be used readily to derive Level A and Level

[[Page 44588]]

B isopleths, as at those sites the calibration hydrophone was located 
at a roughly constant depth of 350-500 m, which may not intersect all 
the sound pressure level (SPL) isopleths at their widest point from the 
sea surface down to the maximum relevant water depth for marine mammals 
of ~2,000 m. At short ranges, where the direct arrivals dominate and 
the effects of seafloor interactions are minimal, the data recorded at 
the deep and slope sites are suitable for comparison with modeled 
levels at the depth of the calibration hydrophone. At longer ranges, 
the comparison with the model--constructed from the maximum SPL through 
the entire water column at varying distances from the airgun array--is 
the most relevant.
    In deep and intermediate-water depths, comparisons at short ranges 
between sound levels for direct arrivals recorded by the calibration 
hydrophone and model results for the same array tow depth are in good 
agreement (Fig. 12 and 14 in Appendix H of NSF-USGS, 2011). 
Consequently, isopleths falling within this domain can be predicted 
reliably by the L-DEO model, although they may be imperfectly sampled 
by measurements recorded at a single depth. At greater distances, the 
calibration data show that seafloor-reflected and sub-seafloor-
refracted arrivals dominate, whereas the direct arrivals become weak 
and/or incoherent. Aside from local topography effects, the region 
around the critical distance is where the observed levels rise closest 
to the model curve. However, the observed sound levels are found to 
fall almost entirely below the model curve. Thus, analysis of the GoM 
calibration measurements demonstrates that although simple, the L-DEO 
model is a robust tool for conservatively estimating isopleths.
    For deep water (>1,000 m), L-DEO used the deep-water radii obtained 
from model results down to a maximum water depth of 2000 m. The radii 
for intermediate water depths (100-1,000 m) were derived from the deep-
water ones by applying a correction factor (multiplication) of 1.5, 
such that observed levels at very near offsets fall below the corrected 
mitigation curve (See Fig. 16 in Appendix H of NSF-USGS, 2011).
    Measurements have not been reported for the single 40-in\3\ airgun. 
L-DEO model results are used to determine the 160-dB (rms) radius for 
the 40-in\3\ airgun at a 12 m tow depth in deep water (See LGL 2018, 
Figure A-2). For intermediate-water depths, a correction factor of 1.5 
was applied to the deep-water model results.
    L-DEO's modeling methodology is described in greater detail in the 
IHA application (LGL 2018). The estimated distances to the Level B 
harassment isopleth for the Langseth's 36-airgun array and single 40-
in\3\ airgun are shown in Table 3.

   Table 3--Predicted Radial Distances From R/V Langseth Seismic Source to Isopleths Corresponding to Level B
                                              Harassment Threshold
----------------------------------------------------------------------------------------------------------------
                                                                                                   Predicted
                                                                                               distances (in m)
                      Source and volume                        Tow depth (m)    Water depth      to the 160-dB
                                                                                    (m)         received sound
                                                                                                     level
----------------------------------------------------------------------------------------------------------------
Single Bolt airgun, 40 in \3\...............................              12          >1,000             \1\ 431
                                                                                   100-1,000             \2\ 647
4 strings, 36 airguns, 6,600 in \3\.........................              12          >1,000           \1\ 6,733
                                                                                   100-1,000          \2\ 10,100
----------------------------------------------------------------------------------------------------------------
\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.

    Predicted distances to Level A harassment isopleths, which vary 
based on marine mammal hearing groups, were calculated based on 
modeling performed by L-DEO using the NUCLEUS software program and the 
NMFS User Spreadsheet, described below. The updated acoustic thresholds 
for impulsive sounds (e.g., airguns) contained in the Technical 
Guidance were presented as dual metric acoustic thresholds using both 
SELcum and peak sound pressure metrics (NMFS 2016). As dual 
metrics, NMFS considers onset of PTS (Level A harassment) to have 
occurred when either one of the two metrics is exceeded (i.e., metric 
resulting in the largest isopleth). The SELcum metric 
considers both level and duration of exposure, as well as auditory 
weighting functions by marine mammal hearing group. In recognition of 
the fact that the requirement to calculate Level A harassment 
ensonified areas could be more technically challenging to predict due 
to the duration component and the use of weighting functions in the new 
SELcum thresholds, NMFS developed an optional User 
Spreadsheet that includes tools to help predict a simple isopleth that 
can be used in conjunction with marine mammal density or occurrence to 
facilitate the estimation of take numbers.
    The values for SELcum and peak SPL for the Langseth 
airgun array were derived from calculating the modified farfield 
signature (Table 4). 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

[[Page 44589]]

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.

      Table 4--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 dB;  (Lpk,flat: 230 dB;  (Lpk,flat: 202 dB;  (Lpk,flat: 218 dB;  (Lpk,flat: 232 dB;
                                                         LE,LF,24h: 183      LE,MF,24h: 185      LE,HF,24h: 155      LE,HF,24h: 185      LE,HF,24h: 203
                                                              dB)                 dB)                 dB)                 dB)                 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              232.83              233.08              232.83              232.07
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
--------------------------------------------------------------------------------------------------------------------------------------------------------

    In order to more realistically incorporate the Technical Guidance's 
weighting functions over the seismic array's full acoustic band, 
unweighted spectrum data for the Langseth's airgun array (modeled in 1 
hertz (Hz) bands) was used to make adjustments (dB) to the unweighted 
spectrum levels, by frequency, according to the weighting functions for 
each relevant marine mammal hearing group. These adjusted/weighted 
spectrum levels were then converted to pressures ([mu]Pa) in order to 
integrate them over the entire broadband spectrum, resulting in 
broadband weighted source levels by hearing group that could be 
directly incorporated within the User Spreadsheet (i.e., to override 
the Spreadsheet's more simple weighting factor adjustment). Using the 
User Spreadsheet's ``safe distance'' methodology for mobile sources 
(described by Sivle et al., 2014) with the hearing group-specific 
weighted source levels, and inputs assuming spherical spreading 
propagation and source velocities and shot intervals specific to each 
of the three planned surveys (Table 1), potential radial distances to 
auditory injury zones were then calculated for SELcum 
thresholds.
    Inputs to the User Spreadsheets in the form of estimated SLs are 
shown in Table 5. User Spreadsheets used by L-DEO to estimate distances 
to Level A harassment isopleths for the 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 (LGL 2018). Outputs from the User 
Spreadsheets in the form of estimated distances to Level A harassment 
isopleths for the surveys are shown in Table 5. As described above, 
NMFS considers onset of PTS (Level A harassment) to have occurred when 
either one of the dual metrics (SELcum and Peak 
SPLflat) is exceeded (i.e., metric resulting in the largest 
isopleth).

                            Table 5--Modeled Radial Distances (m) to Isopleths Corresponding to Level A Harassment Thresholds
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                         Low frequency       Mid frequency      High frequency     Phocid pinnipeds    Otariid pinnipeds
                                                           cetaceans           cetaceans           cetaceans         (underwater)        (underwater)
                                                      (Lpk,flat: 219 dB;  (Lpk,flat: 230 dB;  (Lpk,flat: 202 dB;  (Lpk,flat: 218 dB;  (Lpk,flat: 232 dB;
                                                      LE,LF,24h: 183 dB)  LE,MF,24h: 185 dB)  LE,HF,24h: 155 dB)  LE,HF,24h: 185 dB)  LE,HF,24h: 203 dB)
 
--------------------------------------------------------------------------------------------------------------------------------------------------------
6,600 in \3\ airgun array (Peak SPLflat)............                45.0                13.6              364.75                51.6                10.6
6,600 in \3\ airgun array (SELcum)..................               320.2                N.A.                   1                10.4                N.A.
40 in \3\ airgun (Peak SPLflat).....................                1.76                N.A.                12.5                1.98                N.A.
40 in \3\ airgun (SELcum)...........................                 0.5                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. The best available scientific information was considered 
in conducting marine mammal exposure estimates (the basis for 
estimating take).
    In the planned survey area in the Hawaiian EEZ, densities from 
Bradford et al. (2017) were used, when available. For the pygmy sperm 
whale, dwarf sperm whale, and spinner dolphin, densities from Barlow et 
al. (2009) were used because densities were not provided by Bradford et 
al. (2017). Densities for striped dolphin and Fraser's dolphins were 
revised based on input from the Commission. As noted previously, NMFS 
had divided the unidentified Mesoplodon species' density of 1.89 
animals/1,000 km\2\ from Bradford et al. (2017) by three. For this 
notice, NMFS NMFS assumed that each species of those species could have 
a density of 1.89 animals/1,000 km\2\. For the humpback, sei, minke, 
and killer whales, the calculated take was increased to mean group 
size.

[[Page 44590]]

    For Hawaiian monk seals, NMFS followed the methods used by the U.S. 
Navy (Navy 2017a) to determine densities. The U.S. Navy calculated 
density of Hawaiian monk seal for three areas: The Main Hawaiian 
Islands in waters less than 200 meters, the Northwest Hawaiian Islands 
in waters less than 200 meters, and waters 200 meters deep to the 
Hawaiian EEZ boundary.
    The 200 meter isobath was selected as a boundary because of 
information related to Hawaiian monk seal foraging behavior that came 
out of the final rule for designated critical habitat. Ninety-eight 
percent of recorded dives were within the 200-meter isobath in the Main 
Hawaiian Islands this depth boundary was considered sufficient for 
foraging habitat for adults and juveniles. The area around the Main 
Hawaiian Islands to the 200-meter isobath was estimated to be 6,630 
km\2\ (6,142 km\2\ in the Northwest Hawaiian Islands). The area from 
the 200-meter isobath to the Hawaiian EEZ is estimated to be 2,461,994 
km\2\. The U.S. Navy also assumed that 90 percent of the population 
would occur inside the 200-meter isobath.
    The U.S. Navy used the following calculation to estimate density:

[(number of seals * percent of the population in or out of the 200-m)/
200-m area] * In-water factor

    By applying the U.S. Navy's methodology using updated population 
estimates for the 2017 stock assessment report for the U.S. Pacific 
(Carretta et al. 2018) and haul-out factors, we can estimate Hawaiian 
monk seal density. NMFS had used older abundance data in the proposed 
notice.

Main Hawaiian Islands inside 200 m isobath
[(145 seals * 0.90)/6,630 km\2\] * 0.68 = 0.0134 seals/km\2\
Northwest Hawaiian Islands inside 200 m isobath
[(1,179 seals * 0.90)/6,142 km\2\] * 0.68 = 0. 1175 seals/km\2\
Hawaiian EEZ
[(1,324 * 0.10)/2,461,994 km2] * 0.68 = 0.000037 seals/km\2\

    Based on where the action will occur, it NMFS utilized the density 
estimate for the Hawaiian EEZ.
    There are very few published data on the densities of cetaceans or 
pinnipeds in the Emperor Seamounts area, so NMFS relied on a range of 
sources to establish marine mammal densities. As part of the Navy's 
Final Supplemental Environmental Impact Statement/Supplemental Overseas 
Environmental Impact Statement for SURTASS LFA Sonar Routine Training, 
Testing, and Military Operations, the Navy modelled densities for a 
designated mission area northeast of Japan during the summer season. 
These values were used for the North Pacific right whale, sei whale, 
fin whale, sperm whale, Cuvier's beaked whale, Stejneger's beaked 
whale, and Baird's beaked whale.
    For northern right whale dolphin, Dall's porpoise, and northern fur 
seal, L-DEO used densities from Buckland et al. (1993). Forney and Wade 
(2006) reported a density of 0.3/100 km\2\ for killer whales at 
latitudes 43-48 [deg]N where the planned survey would be conducted. 
Although Miyashita (1993) published data on the abundance of striped, 
Pantropical spotted, bottlenose, and Risso's dolphins, and false killer 
and short-finned pilot whales in the Northwest Pacific Ocean as far 
north as 41[deg]N, the distributional range of the Pantropical spotted 
and bottlenose dolphins does not extend as far north as the planned 
survey area. For the other species, we used data from 40-41[deg]N, 160-
180[deg]E to calculate densities and estimate the numbers of 
individuals that could be exposed to seismic sounds during the survey. 
Risso's dolphin, false killer whale, and short-finned pilot whale are 
expected to be rare in the survey area, and the calculated densities 
were zero. Thus, we used the mean group size from Bradford et al. 
(2017) for Risso's dolphin and short-finned pilot whale, and the mean 
group size of false killer whales from Barlow (2006).
    The short-beaked common dolphin is expected to be rare in the 
Emperor Seamounts survey area; thus, there are no density estimates 
available. L-DEO used the mean group size (rounded up) for the 
California Current from Barlow (2016). The density of Bryde's whale in 
the planned survey area was assumed to be zero, based on information 
from Hakamada et al. (2009, 2017) and Forney et al. (2015); its known 
distribution range does not appear to extend that far north. For this 
species, L-DEO rounded up the mean group size from Bradford et al. 
(2017). For pygmy and dwarf sperm whales, NMFS assumed densities in the 
Emperor Seamounts would be equivalent to those in the Hawaii survey are 
and used densities from Bradford et al. 2017.
    The densities for the remaining species were obtained from 
calculations using data from the papers presented to the IWC. For blue 
and humpback whales, L-DEO used a weighted mean density from Matsuoka 
et al. (2009) for the years 1994-2007 and Hakamada and Matsuoka (2015) 
for the years 2008-2014. L-DEO used Matsuoka et al. (2009) instead of 
Matsuoka et al. (2015), as the later document did not contain all of 
the necessary information to calculate densities. L-DEO used densities 
for their Block 9N which coincides with the planned Emperor Seamounts 
survey area. The density for each survey period was weighted by the 
number of years in the survey period; that is, 14 years for Matsuoka et 
al. (2009) and 7 years for Hakamada and Matsuoka (2015), to obtain a 
final density for the 21-year period. For minke whales L-DEO used the 
estimates of numbers of whales in survey blocks overlapping the Emperor 
Seamounts survey area from Hakamada et al. (2009); densities were 
estimated by dividing the number of whales in Block 9N by the area of 
Block 9N. For gray whales, NMFS used a paper by Rugh et al. (2005) that 
looked at abundance of eastern DPS gray whales. The paper provides mean 
group sizes for their surveys, which ranged from 1 to 2 individuals. 
For purposes of estimating exposures we will assume that the western 
DPS group sizes would not vary greatly from the eastern DPS. As such, 
NMFS assumes that there will be two western DPS gray whales Level B 
takes, based on mean group size.
    Finally, no northern elephant seals have been reported during any 
of the above surveys although Buckland et al. (1993) estimated fur seal 
abundance during their surveys. Telemetry studies, however, indicate 
that elephant seals do forage as far west as the Emperor Seamounts 
survey area. Here, L-DEO assumed a density of 0.00831/1000 km\2\, which 
is 10% of that used by LGL Limited (2017) for an area off the west 
coast of the U.S. However, densities of northern elephant seals in the 
region are expected to be much less than densities of northern fur 
seals. For species that are unlikely to occur in the survey area, such 
as ribbon seals, exposures are set at 5 individuals. Densities for 
animals in Emperor Seamounts are shown in Table 8.

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, radial 
distances from the airgun array to predicted isopleths corresponding to 
the Level A harassment and Level B harassment thresholds are 
calculated, as described above. Those radial distances are then used to 
calculate the area(s) around the airgun array predicted to be 
ensonified to sound levels that exceed the Level A harassment and Level 
B harassment thresholds. The area estimated to be ensonified in a 
single

[[Page 44591]]

day of active seismic operations is then calculated (Table 6) based on 
the areas predicted to be ensonified around the array and the estimated 
trackline distance traveled per day. For purposes of Level B take 
calculations, areas estimated to be ensonified to Level A harassment 
thresholds are subtracted from areas estimated to be ensonified to 
Level B harassment thresholds in order to avoid double counting the 
animals taken (i.e., if an animal is taken by Level A harassment, it is 
not also counted as taken by Level B harassment). The daily ensonified 
areas are multiplied by density estimates for each species to arrive at 
a daily exposure rate. The daily exposure rate is subsequently 
multiplied by the number of planned survey days plus a 25 percent 
contingency factor. Active seismic operations are planned for 13 days 
at Emperor Seamounts and 19 days at Hawaii. Therefore, the number of 
survey days is increased to 16 in the Emperor Seamounts and 24 in 
Hawaii area. Estimated exposures for the Hawaii survey and the Emperor 
Seamounts survey are shown respectively in Table 7 and Table 8.

    Table 6--Areas (km\2\) Estimated To Be Ensonified to Level A and Level B Harassment Thresholds, per Day for Hawaii and Emperor Seamounts Surveys
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                               Daily                       Total survey
                  Survey                                      Criteria                      ensonified    Planned survey     days (25%       Relevant
                                                                                           area (km\2\)        days          increase)     isopleth (m)
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                     Hawaii Level B
--------------------------------------------------------------------------------------------------------------------------------------------------------
Multi-depth line (intermediate water)....  160 dB.......................................           538.5              12              15          10,100
Multi-depth line (deep water)............  160 dB.......................................          2349.8              12              15           6,733
Multi-depth line (total).................  160 dB.......................................          2888.2              12              15           6,733
Deep-water line..........................  160 dB.......................................          2566.3               7               9           6,733
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                   Hawaii Level A \1\
--------------------------------------------------------------------------------------------------------------------------------------------------------
Hawaii...................................  LF Cetacean..................................           115.6              19              24           320.2
                                           MF Cetacean..................................             4.9              19              24            13.6
                                           HF Cetacean..................................            96.8              19              24           268.3
                                           Phocid.......................................            15.7              19              24            43.7
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                Emperor Seamounts Level B
--------------------------------------------------------------------------------------------------------------------------------------------------------
Emperor Seamounts........................  160 dB.......................................          2566.3              13              16           6,733
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                              Emperor Seamounts Level A \1\
--------------------------------------------------------------------------------------------------------------------------------------------------------
Emperor Seamounts........................  LF Cetacean..................................           115.6              13              16           320.2
                                           MF Cetacean..................................             4.9              13              16            13.6
                                           HF Cetacean..................................            96.8              13              16           268.3
                                           Phocid.......................................            15.7              13              16            43.7
                                           Otariid......................................             3.8              13              16            10.6
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ Level A ensonified areas are estimated based on the greater of the distances calculated to Level A isopleths using dual criteria (SELcum and
  peakSPL).


              Table 7--Densities, Exposures, Percentage of Stock or Population Exposed, and Number of Authorized Takes During Hawaii Survey
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                                           Percentage of         Authorized takes
                  Species                               Stock               Density (#/        Total          stock/     -------------------------------
                                                                           1,000 km\2\)      exposures      population        Level A         Level B
--------------------------------------------------------------------------------------------------------------------------------------------------------
Humpback whale............................  Central North Pacific.......  ..............           \4\ 2           <0.01               0               2
                                            Western North Pacific.......  ..............             0.2  ..............  ..............  ..............
Minke whale...............................  Hawaii......................           \3\ 0           \4\ 1           <0.01               0               1
Bryde's whale.............................  Hawaii......................        \1\ 0.72              47             2.8               2              45
Sei whale.................................  Hawaii......................        \1\ 0.16              11             6.2               0              11
Fin whale.................................  Hawaii......................        \1\ 0.06               4             2.7               0               4
Blue whale................................  Central North Pacific.......        \1\ 0.05               5             3.9               0               5
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                       Odontocetes
--------------------------------------------------------------------------------------------------------------------------------------------------------
Sperm whale...............................  Hawaii......................        \1\ 1.86             123             2.7               0             123
Pygmy sperm whale.........................  Hawaii......................        \2\ 2.91             191             2.8               7             184
Dwarf sperm whale.........................  Hawaii......................        \2\ 7.14             470             2.8              16             454
Cuvier's beaked whale.....................  Hawaii pelagic..............        \1\ 0.30              20             2.8               0              20
Longman's beaked whale....................  Hawaii......................        \1\ 3.11             205             2.7               0             205
Blainville's beaked whale.................  Hawaii pelagic..............        \1\ 0.86              57             2.7               0              57
Ginkgo-toothed beaked whale...............  N/A.........................        \6\ 1.89             124             0.5               0             124
Deraniygala's beaked whale................  N/A.........................        \6\ 1.89             124             0.5               0             124
Hubb's beaked whale.......................  N/A.........................        \6\ 1.89             124             0.5               0             124
Rough-toothed dolphin.....................  Hawaii......................       \1\ 29.63           1,949             2.7               0           1,949
Common bottlenose dolphin.................  HI Pelagic..................        \1\ 8.99             592         \7\ 2.7               0             592
                                            Oahu........................  ..............  ..............             1.2  ..............  ..............
                                            HI Islands..................  ..............  ..............             7.0  ..............  ..............
Pantropical spotted dolphin...............  HI Pelagic..................       \1\ 23.32           1,534         \8\ 2.6               0           1,534

[[Page 44592]]

 
                                            Oahu........................  ..............  ..............            N.A.  ..............  ..............
                                            HI Islands..................  ..............  ..............            N.A.  ..............  ..............
Spinner dolphin...........................  HI Pelagic..................        \2\ 6.99             460            N.A.               0             460
                                            HI Island...................  ..............  ..............         \9\ 3.8  ..............  ..............
                                            Oahu/4 island...............  ..............  ..............             6.7  ..............  ..............
Striped dolphin...........................  HI Pelagic..................          \1\ 25           1,644             0.6               0           1,644
Fraser's dolphin..........................  Hawaii......................        \1\ 21.0           1,381             2.7               0           1,381
Risso's dolphin...........................  Hawaii......................        \1\ 4.74             312             2.7               0             312
Melon-headed whale........................  HI Islands..................        \1\ 3.54             810             8.6               0        \10\ 810
                                            Kohala resident.............  ..............  ..............            13.4  ..............  ..............
Pygmy killer whale........................  Hawaii......................        \1\ 4.35             286             2.7               0             286
False killer whale........................  MHI Insular.................        \5\ 0.09               5            11.9               0         \11\ 20
                                            HI Pelagic..................        \5\ 0.06              40             2.6               0              40
Killer whale..............................  Hawaiian Islands............        \1\ 0.06           \4\ 5            2.42               0               5
Short-finned pilot whale..................  Hawaii......................        \1\ 7.97             524             2.7               0             524
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                        Pinnipeds
--------------------------------------------------------------------------------------------------------------------------------------------------------
Hawaiian monk seal........................  Hawaii......................    \3\ 0.000037               3            0.22               0               3
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\-- Bradford et al. 2017.
\2\--Barlow et al. 2009.
\3\--Baker et al. 2016.
\4\--Requested take authorization (Level B only) increased to mean group size from Mobley et al. 2001.
\5\--Bradford et al. 2015.
\6\--From Bradford et al. (2017) for `Unidentified Mesoplodon'.
\7\--Assumes 98.5 percent of takes are from Hawaii pelagic stock (588) with remaining 1 percent from Oahu stock (6) and 0.5 percent from Hawaiian
  Islands (3) stock. Assumed average group size of 9 for Oahu and Hawaii Island stocks.
\8\--Assumes 94.16 percent of takes are from Hawaii pelagic stock (1,461), 5.25 percent are from Hawaiia Island stock (82), and 0.59 are from Oahu
  stock. Populations of insular stocks are unknown.
\9\--Assumes 0.36 percent for Oahu/4-Islands stock (1), 0.95 percent for Hawaii Island stock (4) and remaining from Pelagic stock (459) stocks. NMFS
  will assume average group size of 24 for the Oahu/4-Island and Hawaii Island stock exposures (NMFS 2016).
\10\--Assumes Level B harassment of 3 groups of 20 Kohala resident stock whales and 3 groups of 250 Hawaiian Island stock animals.
\11\--Increased to average group size of 20 (Oleson et al. 2010).

    Changes to Main Hawaiian Islands insular false killer whale take 
estiamtes--NMFS has recalculated exposures of Main Hawaiian Islands 
insular false killer whale DPS due to recently designated critical 
habitat for this species (83 FR 35062; July 24, 2018). A total of 
3,455-kilometers of tracklines will be surveyed around the Main 
Hawaiian Islands where insular false killer whales show a preference 
for deeper waters just offshore (45-meters) to the 3,200-meter depth 
boundary. The majority of the planned tracklines are outside this area 
in waters deeper than 3,200-meters. NMFS used critical habitat to serve 
as the range boundary for this DPS. In order to calculate the amount of 
exposure for Main Hawaiian Islands Insular false killer whales during 
the planned action, NMFS determined the amount of tracklines within the 
DPS's range. There are 236.6 km of planned tracklines in Main Hawaiian 
Islands insular false killer whale range (or about 6.8 percent of the 
tracklines for the entire Hawaii seismic survey). Only portions of 
Tracklines 1 and 2 are within the DPS's range. Because the size of the 
ensonified areas changes with water depth, NMFS determined the amount 
of tracklines in each depth range. All of Trackline 1 takes place in 
deep water (>1,000 meters/141.6 km), and most of Trackline 2 takes 
place in deep water (76.6 km) with 18.4 km in intermediate depth water 
(100 to 1,000 m). Tracklines 1 and 2 would be surveyed twice, once for 
reflection data, and once for refraction data. At a speed of 7.6 km/hr, 
it would take the Langseth about 37.3 hours to survey Trackline 1, and 
25 hours to survey Trackline 2 (both passes), for about 2.6 days in 
total.
    NMFS calculated ensonified area along the tracklines to arrive at a 
total of 3,940-km\2\ within the species' range. As noted previously, a 
contingency of 25 percent was added to the number of survey days, which 
is the equivalent of adding 25 percent to the planned line tracklines. 
The total amount of ensonified area with the 25 percent contingency is 
4,92 5km\2\. Bradford et al. (2015) calculated the density of Main 
Hawaiian Islands Insular false killer whales at 0.09 individuals per 
100 km\2\, which was multiplied by the total ensonified area plus 
contingency, resulting in five Main Hawaiian Island insular false 
killer whale exposures. False killer whales are commonly sighted in 
groups of 10 to 20 (Baird 2009; Baird et al. 2010; Wade and Gerrodette 
1993) with 20 individuals being regarded as about the average group 
size (Oleson et al. 2010). Therefore, authorized Level B harassment 
takes was increased from 5 individuals to 20.
    Changes to melon-headed whale take estimates--NMFS had estimated in 
the proposed notice that there would be 235 Level B harassment takes of 
melon-headed whales from the combined Kohala resident stock and the 
Hawaiian Islands stock. Kohala resident stock members could only be 
affected during Trackline 1 operations off of the Kohala Peninsula and 
the west coast of Hawaii Island in waters of less than 2,500 m of 
water. This segment of the survey represents a small portion of the 
total Hawaiian Island tracklines. The Hawaiian Islands stock of melon-
headed whales may be found along any of the planned tracklines, 
including within the range of the Kohala resident stock. Kohala 
resident whales can be found in large groups of up to several hundred 
with a median group size of 210 (Forney et al. 2017). However, they 
have also been observed in smaller groups of 4 and 17 individuals 
(Aschettino et al. 2011). Additionally, these smaller groups were often 
followed by much larger groups, which suggests that the small groups 
may have branched off from larger groups.
    L-DEO is required to shutdown whenever a melon-headed whale is 
detected while passing through the Kohala resident stock's range. L-DEO

[[Page 44593]]

also intends to pass through this range during daylight hours to 
maximize the potential for detection. PSOs should be able to observe 
the larger groups containing hundreds of animals at a significant 
distance and implement shutdown accordingly. When a small group of 
whales is observed, shutdown will also be implemented and PSOs will 
shift to state of heightened alert since a larger main group may be in 
close proximity. Given this information, NMFS will assume that up to 3 
groups of 20 Kohala resident whales may be taken by Level B harassment 
if they enter the zone undetected by PSOs. This would result in up to 
60 Level B harassment takes. Given the species' large group sizes, NMFS 
will also assume that up to 3 groups of 250 Hawaiian Island animals may 
be taken during the remainder of the cruise outside of the range of 
Kohala resident stock. Therefore, NMFS authorizes the take of up to 810 
melon headed whales.
    Changes to common bottlenose dolphin take estimates--There are four 
individual common bottlenose dolphin stocks within the Hawaiian Islands 
complex. None of the planned survey tracklines will traverse the ranges 
of the Kauai/Niihau or 4-Islands stocks so animals from these stocks 
will not be impacted by seismic activities. In the proposed notice NMFS 
had estimated that a small number of takes would be accrued to the 4 
Islands stock. Therefore, takes of this stock are not authorized in the 
final IHA and NMFS revised the number of authorized takes estimated to 
accrue to the remaining Hawaii pelagic, Oahu, and Hawaiian Islands 
stocks as described below.
    During the survey along Trackline 1 a short time will be spent 
traversing the northern boundary of the Hawaiian Island stock while 
along Trackline 2 the survey will run through the northwest boundary of 
the Oahu stock. The vast majority of planned survey tracklines occur in 
waters that are greater than 1,000 m which marks the boundary between 
the Hawaiian pelagic and Hawaiian insular stocks. According to a GIS 
analysis, an estimated 0.47 percent of all Hawaii tracklines will take 
place in waters less than 1,000 m deep northwest of Oahu along 
Trackline 2 and 1.00 percent will occur in depths less than 1,000 m 
north of Hawaii along Trackline 1. Therefore, NMFS will assume that the 
remaining 98.5% percent (588) of total takes will be accrued by the 
pelagic stock, 0.5 percent (3) will accrue to the Oahu stock and 1 
percent (6) will accrue to the Hawaiian Island stock. Insular stocks 
have an average group size of group size of 8.5 rounded up to 9, so 9 
takes will accrue to the Oahu stock and 9 takes to the Hawaiian Island 
stock (Baird et al. 2002). Note that the ranges of these two insular 
stocks completely encompass the islands for which they are named out to 
the 1,000 m bathymetric contour line. Given such expansive ranges, it 
is unlikely that large numbers of either stock would be concentrated 
near a trackline during the short time the vessel is within the 
delineated stock boundaries.
    Changes to spinner dolphin take estimates--For the final IHA, NMFS 
conducted a comprehensive GIS analysis to determine how spinner dolphin 
takes should be accrued among the various stocks in the region. This 
had not been done for the proposed IHA. There are four stocks of 
spinner dolphins within the U.S. EEZ of the Hawaiian Islands. Planned 
seismic survey tracklines would traverse the ranges of the Hawaii 
Island, Oahu/4-Islands, and Hawaii Pelagic stocks. Stock boundaries for 
the Hawaii Island and Oahu/4-Islands stocks extend out 10 nautical 
miles (nmi) from the coasts of these islands. An estimated 0.36 percent 
of all tracklines will take place in the range of the Oahu/4-Island 
stock northwest of Oahu along Trackline 2, and 0.95 percent will occur 
in the range of the Hawaii Island stock north of Hawaii along Trackline 
1, with remaining takes being accrued by the Hawaii Pelagic stock. This 
results in 1 estimated Oahu/4-Island stock exposure, 4 Hawaii Island 
stock exposures, and 459 Pelagic stock exposures. NMFS will assume 
average group size of 24 individuals for the Oahu/4-Island and Hawaii 
Island stock exposures (NMFS 2016).
    Changes to pantropical spotted dolphin take estimates--A 
comprehensive GIS analysis was also conducted for the pantropical 
spotted dolphin stock takes estimates, which had not been included in 
the proposed IHA. There are four management stocks of pantropical 
spotted dolphins within the Hawaiian Islands EEZ (Oleson et al. 2013) 
including: (1) The Oahu stock, which includes spotted dolphins within 
20 km of Oahu, (2) the 4-Island stock, which includes spotted dolphins 
within 20 km of Maui, Molokai, Lanai, and Kahoolawe collectively, (3) 
the Hawaii Island stock, which includes spotted dolphins found within 
65 km of Hawaii Island, and (4) the Hawaii pelagic stock, which 
includes spotted dolphins inhabiting the waters throughout the Hawaiian 
Islands EEZ, outside of the insular stock areas, but including adjacent 
high seas. Planned seismic survey lines would traverse the Hawaii 
Island, Oahu, and Hawaii Pelagic stocks. An estimated 0.59 percent of 
all tracklines will take place in the range of the Oahu stock northwest 
of Oahu along Trackline 2, and 5.25 percent will occur in the range of 
the Hawaii Island stock north and west of Hawaii along Trackline 1 with 
the remaining accrued by the Hawaii Pelagic stock. This results in an 
estimated 9 Oahu stock exposures, 82 Hawaii Island stock exposures, and 
1,461 Pelagic stock exposures.
    For Hawaiian monk seals, NMFS used an updated abundance estimate 
(Baker et al. 2016) recommended by the Commission to estimate density. 
NMFS multiplied the updated estimated density by the daily ensonified 
area (160 dB zone) on one day, times the 1.25 percent operational 
contingency. Since the planned action will take place in different 
water depths, there are two different daily ensonified areas. For deep 
water (>1,000 meters), the daily ensonified area is 2,349.8 km\2\. For 
intermediate depths (100-1,000 meters), the daily ensonified area is 
538.5 km\2\. The vast majority of the survey (3,403 kilometers) will 
take place in deep water. Only 52 km will take place in intermediate 
depths. However, use of the updated abundance and density estimates 
resulted in the same number of authorized Level B harassment takes (3) 
that was included in the proposed IHA.

        Table 8--Densities, Expsoures, Percentage of Stock or Population Exposed, and Number of Authorized Takes During Emperor Seamounts Survey
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                             Estimated                     Percentage of         Authorized takes
             Species                               Stock                    density (#/        Total        population   -------------------------------
                                                                            1000 km\2\)      exposures     (total takes)      Level A         Level B
--------------------------------------------------------------------------------------------------------------------------------------------------------
Gray whale.......................  N/A..................................            N.A.           \2\ 2            1.43               0               2
North Pacific right whale........  N/A..................................        \1\ 0.01          \10\ 2            0.45               0               2
Humpback whale...................  Central North Pacific................        \1\ 0.41              18       \11\ 0.17          \13\ 2         \11\ 16
                                   Western North Pacific DPS............  ..............  ..............       \11\ 0.18  ..............  ..............
Minke whale......................  N/A..................................            2.48             103            0.47               5              98

[[Page 44594]]

 
Bryde's whale....................  N/A..................................            N.A.           \3\ 2           <0.01               0               2
Sei whale........................  N/A..................................        \1\ 0.29              14            0.05           \3\ 3              11
Fin whale........................  N/A..................................        \1\ 0.20               8            0.06               0               8
Blue whale.......................  Central North Pacific................            0.13               5             3.7               0               5
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                       Odontocetes
--------------------------------------------------------------------------------------------------------------------------------------------------------
Sperm whale......................  N/A..................................        \1\ 2.20              90            0.30               0              90
Pygmy sperm whale................  N/A..................................        \4\ 2.91             121             1.7               0             121
Dwarf sperm whale................  N/A..................................        \4\ 7.14             298             1.7               0             298
Cuvier's beaked whale............  N/A..................................        \1\ 5.40             225            1.11               0             225
Stejner's beaked whale...........  Alaska...............................         \1\ 0.5              21            0.08               0              21
Baird's beaked whale.............  N/A..................................         \1\ 2.9             121            1.19               0             121
Short-beaked common dolphin......  N/A..................................         \5\ 180            N.A.           <0.01               0             180
Striped dolphin..................  N/A..................................        \6\ 9.21             384            0.04               0             384
Pacific white-sided dolphin......  N/A..................................       \7\ 68.81           2,870            0.29               0           2,870
Northern right whale dolphin.....  N/A..................................        \7\ 3.37             141            0.04               0             141
Risso's dolphin..................  N/A..................................          \3\ 27           1,126            1.02               0           1,126
False killer whale...............  N/A..................................          \5\ 10             417             2.5               0             417
Killer whale.....................  N/A..................................   \8\ \12\ 3.00           1,253            14.7               0           1,253
Short-finned pilot whale.........  N/A..................................          \3\ 41           1,713             3.2               0           1,713
Dall's porpoise..................  N/A..................................           35.46           1,479            0.13              56           1,423
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                        Pinnipeds
--------------------------------------------------------------------------------------------------------------------------------------------------------
Northern fur seal................  N/A..................................        \7\ 3.56             149            0.01               0             149
Northern elephant seal...........  N/A..................................            8.31             343            0.15               0             343
Ribbon seal......................  Alaska...............................            N.A.           \9\ 5           <0.01               0               5
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\--Navy 2017b. Final Supplemental Environmental Impact Statement/Supplemental Overseas Environmental Impact Statement.--SURTASS.
\2\--Mean group size based on Rugh et al. (2005).
\3\--Mean group size from Bradford et al. (2017).
\4\--Bradford et al. (2017).
\5\--Mean group size from Barlow (2016).
\6\--Miyashita (1993).
\7\--Buckland et al. (1993).
\8\--Forney and Wade (2006).
\9\--Estimated exposures increased to 5 for pinnipeds.
\10\--Mean group size from Matsuoka et al. (2009).
\11\--Based on population size, take is split proportionally between central north Pacific (91.2 percent of total take) and western north Pacific DPS
  stocks (9.8 percent of total take). Assumes 2 Level B harassment takes of western north Pacific DPS.
\12\--Density is based on number of animals/100 km\2\.
\13\--Mean group size from Mobley et al. (2001).

    The only stocks that occur in both the Emperor Seamounts and the 
Hawaiian Islands are the Central North Pacific (CNP) humpback whale, 
Western North Pacific (WNP) humpback whale, and Central North Pacific 
(CNP) blue whale stocks. NMFS combined take estimates from both surveys 
and calculated the percentage of each stock taken. The results were 
0.18 percent for the CNP humpback stock, 0.36 percent for the WNP 
humpback stock, and 7.5 percent for the CNP blue whale stock.
    It should be noted that authorized take numbers shown in Tables 7 
and 8 are expected to be conservative for several reasons. First, in 
the calculations of estimated take, 25 percent has been added in the 
form of operational survey days to account for the possibility of 
additional seismic operations associated with airgun testing and repeat 
coverage of any areas where initial data quality is sub-standard, and 
in recognition of the uncertainties in the density estimates used to 
estimate take as described above. Additionally, marine mammals would be 
expected to move away from a loud sound source that represents an 
aversive stimulus, such as an airgun array, potentially reducing the 
number of Level A takes. 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.

Mitigation

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

[[Page 44595]]

    (2) the practicability of the measures for applicant 
implementation, which may consider such things as cost, impact on 
operations.
    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 planned mitigation measures 
into their project description based on the above sources.
    To reduce the potential for disturbance from acoustic stimuli 
associated with the activities, L-DEO will implement mitigation 
measures for marine mammals. Mitigation measures that will be adopted 
during the planned surveys include (1) Vessel-based visual mitigation 
monitoring; (2) Vessel-based passive acoustic monitoring; (3) 
Establishment of an exclusion zone; (4) Power down procedures; (5) 
Shutdown procedures; (6) Ramp-up procedures; and (7) Vessel strike 
avoidance measures. Note that additional measures have been included in 
the final IHA that were not contained in the proposed IHA. These 
measures are described in the following sections.

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 meter 
exclusion zone, out to a radius of 1,000 meters from the edges of the 
airgun array (500-1,000 meters). 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. Note that L-DEO must monitor the Level B harassment zone beyond 
1,000 meters and enumerate any takes beyond this buffer zone.
    L-DEO must use at least five dedicated, trained, NMFS-approved 
Protected Species Observers (PSOs). The PSOs must have no tasks other 
than to conduct observational effort, record observational data, and 
communicate with and instruct relevant vessel crew with regard to the 
presence of marine mammals and mitigation requirements. PSO resumes 
shall be provided to NMFS for approval.
    At least one of the visual and two of the acoustic PSOs aboard the 
vessel must have a minimum of 90 days at-sea experience working in 
those roles, respectively, during a deep penetration (i.e., ``high 
energy'') seismic survey, with no more than 18 months elapsed since the 
conclusion of the at-sea experience. One visual PSO with such 
experience shall be designated as the lead for the entire protected 
species observation team. The lead PSO shall serve as primary point of 
contact for the vessel operator and ensure all PSO requirements per the 
IHA are met. To the maximum extent practicable, the experienced PSOs 
should be scheduled to be on duty with those PSOs with appropriate 
training but who have not yet gained relevant experience.
    During survey operations (e.g., any day on which use of the 
acoustic source is planned to occur, and whenever the acoustic source 
is in the water, whether activated or not), a minimum of two visual 
PSOs must be on duty and conducting visual observations at all times 
during daylight hours (i.e., from 30 minutes prior to sunrise through 
30 minutes following sunset) and 30 minutes prior to and during 
nighttime ramp-ups of the airgun array. Visual monitoring of the 
exclusion and buffer zones must begin no less than 30 minutes prior to 
ramp-up and must continue until one hour after use of the acoustic 
source ceases or until 30 minutes past sunset. Visual PSOs shall 
coordinate to ensure 360[deg] visual coverage around the vessel from 
the most appropriate observation posts, and shall conduct visual 
observations using binoculars and the naked eye while free from 
distractions and in a consistent, systematic, and diligent manner. PSOs 
shall establish and monitor the exclusion and buffer zones. These zones 
shall be based upon the radial distance from the edges of the acoustic 
source (rather than being based on the center of the array or around 
the vessel itself). During use of the acoustic source (i.e., anytime 
airguns are active, including ramp-up), occurrences of marine mammals 
within the buffer zone (but outside the exclusion zone) shall be 
communicated to the operator to prepare for the potential shutdown or 
powerdown of the acoustic source.
    During use of the airgun (i.e., anytime the acoustic source is 
active, including ramp-up), occurrences of marine mammals within the 
buffer zone (but outside the exclusion zone) should be communicated to 
the operator to prepare for the potential shutdown or powerdown of the 
acoustic source. Visual PSOs will immediately communicate all 
observations to the on duty acoustic PSO(s), including any 
determination by the PSO regarding species identification, distance, 
and bearing and the degree of confidence in the determination. Any 
observations of marine mammals by crew members shall be relayed to the 
PSO team. During good conditions (e.g., daylight hours; Beaufort sea 
state (BSS) 3 or less), visual PSOs shall conduct observations when the 
acoustic source is not operating for comparison of sighting rates and 
behavior with and without use of the acoustic source and between 
acquisition periods, to the maximum extent practicable. Visual PSOs may 
be on watch for a maximum of two 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.
    For the final IHA, NMFS had added the requirement L-DEO must make a 
good faith effort to schedule their surveys to maximize the amount of 
seismic activity that takes place during daylight hours within the 
defined ranges of the Kohala resident stock of melon-headed whale and 
the Main Hawaiian Islands insular stock of fales killer whales. This 
will greatly assist PSOs in their efforts to effectively monitor these 
species. Furthermore, L-DEO must implement shutdown procedures if a 
melon-headed whale or group of melon-headed whales is observed in the 
Kohala resident stock's range.

[[Page 44596]]

Passive Acoustic Monitoring

    Acoustic monitoring means the use of trained personnel (sometimes 
referred to as passive acoustic monitoring (PAM) operators, herein 
referred to as acoustic PSOs) to operate PAM equipment to acoustically 
detect the presence of marine mammals. Acoustic monitoring involves 
acoustically detecting marine mammals regardless of distance from the 
source, as localization of animals may not always be possible. Acoustic 
monitoring is intended to further support visual monitoring (during 
daylight hours) in maintaining an exclusion zone around the sound 
source that is clear of marine mammals. In cases where visual 
monitoring is not effective (e.g., due to weather, nighttime), acoustic 
monitoring may be used to allow certain activities to occur, as further 
detailed below.
    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, if PSOs are 
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 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 five hours 
without acoustic monitoring during daylight hours. In the proposed IHA, 
NMFS stated that only two hours of operations would be allowed without 
acoustic monitoring. However, L-DEO reported that approximately five 
hours are required to redeploy the spare PAM system if the primary PAM 
system fails. Note that operations may continue 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 five 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.

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 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

[[Page 44597]]

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.
     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) shutdown 
must occur under the following conditions:
     A marine mammal appears within or enters the applicable 
exclusion zone; and
     A marine mammal (other than delphinids, see below) is 
detected acoustically and localized within the applicable exclusion 
zone.
    The shutdown requirements described below have been added to the 
final IHA as they were not included in the proposed IHA. Under the 
following conditions L-DEO must implement shutdown:
     A marine mammal species, for which authorization was 
granted but the takes have been met, approaches the Level A or B 
harassment zones;
     A large whale with a calf or an aggregation of large 
whales is observed regardless of the distance from the Langseth;
     A melon-headed whale or group of melon-headed whales is 
observed in the range of the Kohala resident stock. This stock is found 
off the the Kohala Peninsula and west coast of Hawaii Island and at a 
depth of less than 2,500 m (Carretta et al. 2018). L-DEO will attempt 
to time their seismic operations along Trackline 1 so they will 
traverse the Kohala resident stock's range during daytime.
     A spinner or bottlenose dolphin or group of dolphins is 
observed approaching or is within the Level B harassment zone in the 
habitat of the specific MHI insular stock if the authorized takes have 
been met for any of these stocks.
    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, pygmy sperm, 
dwarf sperm, and beaked 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 
including Tursiops, Delphinus, Lagenodelphis, Lagenorhynchus, 
Lissodelphis, Stenella and Steno. 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. Note that when the 
acoustic source is powered down to the 40-in\3\ airgun due to the 
presence of specified dolphins, a shutdown zone of 100 m and Level B 
harassment zone of 430 m will be in effect for species other than 
specified dolphin genera that may approach the survey vessel. This 
mitigation measure had not been included in the notice of proposed IHA.
    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 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.
    We include this small delphinoid exception because power-down/
shutdown requirements for small delphinoids under all circumstances 
represent practicability concerns without likely commensurate benefits 
for the animals in question. Small delphinoids are generally the most 
commonly observed marine mammals in the specific geographic region and 
would typically be the only marine mammals likely to intentionally 
approach the vessel. As described above, auditory injury is extremely

[[Page 44598]]

unlikely to occur for mid-frequency cetaceans (e.g., delphinids), as 
this group is relatively insensitive to sound produced at the 
predominant frequencies in an airgun pulse while also having a 
relatively high threshold for the onset of auditory injury (i.e., 
permanent threshold shift).
    A large body of anecdotal evidence indicates that small delphinoids 
commonly approach vessels and/or towed arrays during active sound 
production for purposes of bow riding, with no apparent effect observed 
in those delphinoids (e.g., Barkaszi et al., 2012). The potential for 
increased shutdowns resulting from such a measure would require the 
Langseth to revisit the missed track line to reacquire data, resulting 
in an overall increase in the total sound energy input to the marine 
environment and an increase in the total duration over which the survey 
is active in a given area. Although other mid-frequency hearing 
specialists (e.g., large delphinoids) are no more likely to incur 
auditory injury than are small delphinoids, they are much less likely 
to approach vessels. Therefore, retaining a power-down/shutdown 
requirement for large delphinoids would not have similar impacts in 
terms of either practicability for the applicant or corollary increase 
in sound energy output and time on the water. We do anticipate some 
benefit for a power-down/shutdown requirement for large delphinoids in 
that it simplifies somewhat the total range of decision-making for PSOs 
and may preclude any potential for physiological effects other than to 
the auditory system as well as some more severe behavioral reactions 
for any such animals in close proximity to the source vessel.
    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 30 minutes for all other species with no further observation of the 
marine mammal(s).
    In the event of a live stranding (or near-shore atypical milling) 
event, L-DEO must adhere to recently established protocols, which were 
not contained in the proposed IHA. If the stranding event occurs within 
50 km of the survey operations, where the NMFS stranding network is 
engaged in herding or other interventions to return animals to the 
water, the Director of OPR, NMFS (or designee) will advise the IHA-
holder of the need to implement shutdown procedures for all active 
acoustic sources operating within 50 km of the stranding. Shutdown 
procedures for live stranding or milling marine mammals include the 
following:
     If at any time, the marine mammal(s) die or are 
euthanized, or if herding/intervention efforts are stopped, the 
Director of OPR, NMFS (or designee) will advise the IHA-holder that the 
shutdown around the animals' location is no longer needed.
     Otherwise, shutdown procedures will remain in effect until 
the Director of OPR, NMFS (or designee) determines and advises the IHA-
holder that all live animals involved have left the area (either of 
their own volition or following an intervention).
     If further observations of the marine mammals indicate the 
potential for re-stranding, additional coordination with the IHA-holder 
will be required to determine what measures are necessary to minimize 
that likelihood (e.g., extending the shutdown or moving operations 
farther away) and to implement those measures as appropriate.
    Shutdown procedures are not related to the investigation of the 
cause of the stranding and their implementation is not intended to 
imply that the specified activity is the cause of the stranding. 
Rather, shutdown procedures are intended to protect marine mammals 
exhibiting indicators of distress by minimizing their exposure to 
possible additional stressors, regardless of the factors that 
contributed to the stranding.

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.
    5. When marine mammals are sighted while a vessel is underway, the 
vessel should take action as necessary to avoid violating the relevant 
separation distance (e.g., attempt to remain parallel to the animal's 
course, avoid excessive speed or abrupt changes in direction until the 
animal has left the area). If marine mammals are sighted within the 
relevant separation distance, the vessel should reduce speed and shift 
the engine to neutral, not engaging the engines until animals are clear 
of the area. This recommendation does not apply to any vessel towing 
gear.
    We have carefully evaluated the suite of mitigation measures 
described here and considered a range of other measures in the context 
of ensuring that we prescribe the means of effecting the least 
practicable adverse impact on the affected marine mammal species and 
stocks and their habitat. Based on our evaluation of the planned 
measures, NMFS has determined that the mitigation measures provide the 
means effecting the least practicable impact on the affected species or 
stocks and their habitat, paying particular attention to rookeries, 
mating grounds, and areas of similar significance.

[[Page 44599]]

Monitoring and Reporting

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

Vessel-Based Visual Monitoring

    As described above, PSO observations would take place during 
daytime airgun operations and nighttime start ups (if applicable) of 
the airguns. During seismic operations, at least five visual PSOs would 
be based aboard the Langseth. Monitoring shall be conducted in 
accordance with the following requirements:
     The operator shall provide PSOs with bigeye binoculars 
(e.g., 25 x 150; 2.7 view angle; individual ocular focus; height 
control) of appropriate quality (i.e., Fujinon or equivalent) solely 
for PSO use. These shall be pedestal-mounted on the deck at the most 
appropriate vantage point that provides for optimal sea surface 
observation, PSO safety, and safe operation of the vessel.
     The operator will work with the selected third-party 
observer provider to ensure PSOs have all equipment (including backup 
equipment) needed to adequately perform necessary tasks, including 
accurate determination of distance and bearing to observed marine 
mammals. (c) 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.
     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;
     Dates and times (Greenwich Mean Time) of survey effort and 
times corresponding with PSO effort;
     Vessel location (latitude/longitude) when survey effort 
began and ended and vessel location at beginning and end of visual PSO 
duty shifts;
     Vessel heading and speed at beginning and end of visual 
PSO duty shifts and upon any line change;
     Environmental conditions while on visual survey (at 
beginning and end of PSO shift and whenever conditions

[[Page 44600]]

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);
     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.
    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 must 
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 report must 
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 must 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 must be made 
available to NMFS. The report must summarize the information submitted 
in interim monthly reports as well as additional data collected as 
described above and the IHA. The draft report must be accompanied by a 
certification from the lead PSO as to the accuracy of the report, and 
the lead PSO may submit directly NMFS a statement concerning 
implementation and effectiveness of the required mitigation and 
monitoring. A final report must be submitted within 30 days following 
resolution of any comments on the draft report.

Reporting Injured or Dead Marine Mammals

    NMFS has revised the standard protcols that apply when an injured 
or dead marine mammal is discovered and has included them here. These 
updated protocols were not described in the proposed IHA. In the event 
that personnel involved in survey activities covered by the 
authorization discover an injured or dead marine mammal, the IHA-holder 
shall report the incident to the Office of Protected Resources (OPR), 
NMFS and to the NMFS Pacific Islands Regional Stranding Coordinator as 
soon as feasible. The report must include the following information:
     Time, date, and location (latitude/longitude) of the first 
discovery (and updated location information if known and applicable);
     Species identification (if known) or description of the 
animal(s) involved;
     Condition of the animal(s) (including carcass condition if 
the animal is dead);
     Observed behaviors of the animal(s), if alive;
     If available, photographs or video footage of the 
animal(s); and
     General circumstances under which the animal was 
discovered.
    Additional Information Requests--If NMFS determines that the 
circumstances of any marine mammal stranding found in the vicinity of 
the activity suggest investigation of the association with survey 
activities is warranted (example circumstances noted below), and an 
investigation into the stranding is being pursued, NMFS will submit a 
written request to the IHA-holder indicating that the following initial 
available information must be provided as soon as possible, but no 
later than 7 business days after the request for information.
     Status of all sound source use in the 48 hours preceding 
the estimated time of stranding and within 50 km of the discovery/
notification of the stranding by NMFS; and
     If available, description of the behavior of any marine 
mammal(s) observed preceding (i.e., within 48 hours and 50 km) and 
immediately after the discovery of the stranding.
    Examples of circumstances that could trigger the additional 
information request include, but are not limited to, the following:
     Atypical nearshore milling events of live cetaceans;

[[Page 44601]]

     Mass strandings of cetaceans (two or more individuals, not 
including cow/calf pairs);
     Beaked whale strandings;
     Necropsies with findings of pathologies that are unusual 
for the species or area; or
     Stranded animals with findings consistent with blast 
trauma.
    In the event that the investigation is still inconclusive, the 
investigation of the association of the survey activities is still 
warranted, and the investigation is still being pursued, NMFS may 
provide additional information requests, in writing, regarding the 
nature and location of survey operations prior to the time period 
above.
    Vessel Strike--In the event of a ship strike of a marine mammal by 
any vessel involved in the activities covered by the authorization, L-
DEO must shall report the incident to OPR, NMFS and to regional 
stranding coordinators as soon as feasible. The report must include the 
following information:
     Time, date, and location (latitude/longitude) of the 
incident;
     Species identification (if known) or description of the 
animal(s) involved;
     Vessel's speed during and leading up to the incident;
     Vessel's course/heading and what operations were being 
conducted (if applicable);
     Status of all sound sources in use;
     Description of avoidance measures/requirements that were 
in place at the time of the strike and what additional measures were 
taken, if any, to avoid strike;
     Environmental conditions (e.g., wind speed and direction, 
Beaufort sea state, cloud cover, visibility) immediately preceding the 
strike;
     Estimated size and length of animal that was struck;
     Description of the behavior of the marine mammal 
immediately preceding and following the strike;
     If available, description of the presence and behavior of 
any other marine mammals immediately preceding the strike;
     Estimated fate of the animal (e.g., dead, injured but 
alive, injured and moving, blood or tissue observed in the water, 
status unknown, disappeared); and
     To the extent practicable, photographs or video footage of 
the animal(s).

Negligible Impact Analysis and Determination

    NMFS has defined negligible impact as ``an impact resulting from 
the specified activity that cannot be reasonably expected to, and is 
not reasonably likely to, adversely affect the species or stock through 
effects on annual rates of recruitment or survival'' (50 CFR 216.103). 
A negligible impact finding is based on the lack of likely adverse 
effects on annual rates of recruitment or survival (i.e., population-
level effects). An estimate of the number of takes alone is not enough 
information on which to base an impact determination. In addition to 
considering estimates of the number of marine mammals that might be 
``taken'' through harassment, NMFS considers other factors, such as the 
likely nature of any responses (e.g., intensity, duration), the context 
of any responses (e.g., critical reproductive time or location, 
migration), as well as effects on habitat, and the likely effectiveness 
of the mitigation. We also assess the number, intensity, and context of 
estimated takes by evaluating this information relative to population 
status. Consistent with the 1989 preamble for NMFS' 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 7 and 8, 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 surveys, even in the absence of 
planned mitigation. As discussed in the Potential Effects section, non-
auditory physical effects, stranding, and vessel strike are not 
expected to occur.
    NMFS has authorized a limited number of instances of Level A 
harassment of 6 species and Level B harassment of 39 marine mammal 
species. However, we believe that any PTS incurred in marine mammals as 
a result of the 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). We expect that the majority of takes 
would be in the form of short-term Level B behavioral harassment in the 
form of temporary avoidance of the area or decreased foraging (if such 
activity were occurring), reactions that are considered to be of low 
severity and with no lasting biological consequences (e.g., Southall et 
al., 2007).
    Potential impacts to marine mammal habitat were discussed 
previously in this document (see Potential Effects of the Specified 
Activity on Marine Mammals and their Habitat). Marine mammal habitat 
may be impacted by elevated sound levels, but these impacts would be 
temporary. Feeding behavior is not likely to be significantly impacted, 
as marine mammals appear to be less likely to exhibit behavioral 
reactions or avoidance responses while engaged in feeding activities 
(Richardson et al., 1995). 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 (up to 24 days for Hawaii survey) and temporary nature of the 
disturbance as well as the availability of similar habitat and 
resources in the surrounding area, the impacts to marine mammals and 
the food sources that they utilize are not expected to cause 
significant or long-term consequences for individual marine mammals or 
their populations.
    The activity is expected to impact a small percentage of all marine 
mammal stocks that would be affected by L-DEO's planned survey (less 
than 15 percent percent of all species, including those taken by both 
surveys). Additionally, the acoustic ``footprint'' of the planned 
surveys would be small relative to the ranges of the marine mammals 
that would potentially be affected. Sound levels would increase in the 
marine environment in a relatively small area surrounding the vessel 
compared to the range of the marine mammals within the planned survey 
area.
    The required mitigation measures are expected to reduce the 
severity of takes by allowing for detection of marine

[[Page 44602]]

mammals in the vicinity of the vessel by visual and acoustic observers, 
and by minimizing the severity of any potential exposures via power 
downs and/or shutdowns of the airgun array. Based on previous 
monitoring reports for substantially similar activities that have been 
previously authorized by NMFS, we expect that the required mitigation 
will be effective in preventing at least some extent of potential PTS 
in marine mammals that may otherwise occur in the absence of the 
mitigation.
    The ESA-listed marine mammal species under our jurisdiction that 
are likely to be taken by the planned surveys include the endangered 
sei, fin, blue, sperm, gray, North Pacific Right, Western North Pacific 
DPS humpback, and Main Hawaiian Islands Insular DPS false killer whale 
as well as the Hawaiian monk seal. We have authorized very small 
numbers of takes for these species relative to their population sizes. 
Therefore, we do not expect population-level impacts to any of these 
species. The other marine mammal species that may be taken by 
harassment during the survey are not listed as threatened or endangered 
under the ESA. With the exception of the northern fur seal, none of the 
non-listed marine mammals for which we have authorized take are 
considered ``depleted'' or ``strategic'' by NMFS under the MMPA.
    The tracklines of the Hawaii survey either traverse or are proximal 
to BIAs for 11 species that NMFS has authorized for take. Ten of the 
BIAs pertain to small and resident cetacean populations while a 
breeding BIA has been delineated for humpback whales. However, this 
designation is only applicable to humpback whales in the December 
through March timeframe (Baird et al., 2015). Since the Hawaii survey 
is in September, there will be no effects on humpback whales. For 
cetacean species with small and resident BIAs in the Hawaii survey 
area, that designation is applicable year-round. There are up to 24 
days of seismic operations planned for the Hawaii survey. Only a 
portion of those days would involve seismic operations within BIA 
boundaries along Tracklines 1 and 2. Time spent in any single BIA 
during a trackline pass would be less than a day. 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 
mortality, the most likely impact to prey species from survey 
activities would be temporary avoidance of the affected area. 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.
    NMFS has included a number of mitigation and monitoring measures to 
reduce potential impacts to small and resident populations in the Main 
Hawaiian Islands. Given the small population and large recorded group 
sizes of Kohala resident melon-headed whales, L-DEO must shut down when 
a melon-headed whale or group of melon-headed whales is observed in the 
range of the Kohala resident stock. Furthermore, L-DEO will plan to 
time their seismic operations along Trackline 1 so they will traverse 
the Kohala resident stock's range during daytime. L-DEO will similarly 
plan to conduct daylight crossings of designated critical habitat for 
the Main Hawaiian Island insular false killer whale. Spinner and 
bottlenose dolphin stocks also have small and resident populations. 
Therefore, when a group of dolphins is observed approaching or is 
within the Level B harassment zone in the habitat of the specific MHI 
insular stock L-DEO must shut down if the authorized takes have been 
met for any of these stocks. Additional protective measures include 
mandatory shutdown when a large whale with a calf or an aggregation of 
large whales is observed regardless of the distance from the Langseth;
    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 that authorized take numbers will 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 marine mammal species or 
stocks through effects on annual rates of recruitment or survival:
     No mortality is anticipated or authorized;
     The planned activity is temporary and of relatively short 
duration;
     The anticipated impacts of the activity on marine mammals 
would primarily be temporary behavioral changes due to avoidance of the 
area around the survey vessel;
     The number of instances of PTS that may occur are expected 
to be limited. Instances of PTS that are incurred in marine mammals 
would be of a low level, due to constant movement of the vessel and of 
the marine mammals in the area, and the nature of the survey design 
(not concentrated in areas of high marine mammal concentration);
     The availability of alternate areas of similar habitat 
value for marine mammals to temporarily vacate the survey area during 
the survey to avoid exposure to sounds from the activity;
     The potential adverse effects on fish or invertebrate 
species that serve as prey species for marine mammals from the survey 
will be temporary and spatially limited;
     The required mitigation measures, including visual and 
acoustic monitoring, power-downs, and shutdowns, are expected to 
minimize potential impacts to marine mammals. Specific mitigation 
measures added to this final IHA include shutting down when a large 
whale with a calf or an aggregation of large whales is observed; 
shutting down when a melon-headed whale or group of melon-headed whales 
is observed in the range of the Kohala resident stock; shutting down 
when a spinner or bottlenose dolphin or group of dolphins approach the 
Level B harassment zone in the habitat of the specific MHI insular 
stock if the authorized takes have been met for any of these stocks; 
and timing surveys to traverse ranges of the Kohala resident stock of 
melon-headed whale and the Main Hawaiian Islands insular stock of false 
killer whales during daylight hours.
    Based on the analysis contained herein of the likely effects of the 
specified activity on marine mammals and their habitat, and taking into 
consideration the implementation of the required monitoring and 
mitigation measures, NMFS finds that the total marine mammal take from 
the planned activity will have a negligible impact on all affected 
marine mammal species or stocks.

Small Numbers

    As noted above, only small numbers of incidental take may be 
authorized under section 101(a)(5)(D) of the MMPA for specified 
activities other than military readiness activities. The MMPA does not 
define small numbers; so, in practice, where estimated numbers are 
available, NMFS compares the number of individuals taken to the most 
appropriate estimation of abundance of

[[Page 44603]]

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. 
Tables 7 and 8 provide numbers of authorized take by Level A harassment 
and Level B harassment. These are the numbers we use for purposes of 
the small numbers analysis.
    The numbers of marine mammals for which we have authorized take 
across the two surveys would be considered small relative to the 
relevant populations (a maximum of 14.7 percent) for the species for 
which abundance estimates are available. Several small resident or 
insular populations that could experience Level B harassment during the 
Hawaii survey were discussed in the Estimated Take section. For the 
Kohala resident stock of melo-headed whales (pop. 447), NMFS assumed 
that up to 3 groups of 20 Kohala residents could be taken by Level B 
harassment, representing 13.4 percent of the Kohala stock, if they 
enter the zone undetected by PSOs. Additionally, the range of the 
Hawaiian Island stock overlaps the range of the Kohala resident stock. 
Therefore, any melon-headed whale takes within the Kohala resident 
stock's range could also be from either stock. Sesimic operations will 
occur in the ranges of the Hawaiian Island stock (pop. 128) and Oahu 
stock (pop. 743) of common bottlenose dolphins. Based on GIS analysis 
of the tracklines and the ranges of the stocks, NMFS determined that 7 
percent of the Hawaii Island stock and 1.2 percent of the Oahu stock 
could be exposed to Level B harassment. Similar GIS analysis of the 
Hawaii Island (pop. 631) and Oahu/4-Island (pop. 355) stocks of spinner 
dolphins resulted in estimated Level B harassment of 3.8 percent of the 
Hawaii Islands stock population and 6.7 percent of the Oahu/4-Island 
stock population. Analysis of pantropical spotted dolphins determined 
that there would be 9 Oahu stock exposures and 82 Hawaii Island stock 
exposures. The populations of these stocks are unknown, so the 
percentage of stocks affected cannot be determined. However, the large 
ranges of these species (up to 20 km from Oahu and 65 km from Hawaii) 
make it likely that the survey would only impact limited numbers of 
these stocks.
    Based on the analysis contained herein of the planned activity 
(including the required mitigation and monitoring measures) and the 
anticipated take of marine mammals, NMFS finds that small numbers of 
marine mammals will be taken relative to the population size of the 
affected species.

Unmitigable Adverse Impact Analysis and Determination

    There are no relevant subsistence uses of the affected marine 
mammal stocks or species implicated by this action. Therefore, NMFS has 
determined that the total taking of affected species or stocks would 
not have an unmitigable adverse impact on the availability of such 
species or stocks for taking for subsistence purposes.

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 Permits and Conservation Division issued a Biological 
Opinion on August 24, 2018 to NMFS's Office of Protected Resources 
which concluded that the specified activities are not likely to 
jeopardize the continued existence of the North Pacific right whale, 
sei whale, fin whale, blue whale, sperm whale, Western North Pacific 
DPS humpback whale, gray whale, Hawaiian Islands Insular DPS false 
killer whale, and the Hawaiian monk seal or adversely modify critical 
habitat because none exists within the action area.

National Environmental Policy Act

    To comply with the National Environmental Policy Act of 1969 (NEPA; 
42 U.S.C. 4321 et seq.) and NOAA Administrative Order (NAO) 216-6A, 
NMFS must review the proposed action (i.e., the issuance of regulations 
and an LOA) with respect to potential impacts on the human environment.
    Accordingly, NMFS has adopted the L-DEO Final Environmental 
Assessment (EA), Environmental Assessment/Analysis of Marine 
Geophysical Surveys by the R/V Marcus G. Langseth in the North Pacific 
Ocean, 2018/2019 and after an independent evaluation of the document 
found that it included adequate information analyzing the effects on 
the human environment of issuing incidental take authorizations. In 
August 2018, NMFS issued a Finding of No Significant Impact (FONSI).

Authorization

    As a result of these determinations, we have issued an IHA to L-DEO 
for conducting seismic surveys in the Pacific Ocean near the main 
Hawaiian Islands and the Emperor Seamounts area from September 1, 2018 
through August 31, 2019, provided the previously mentioned mitigation, 
monitoring, and reporting requirements are incorporated.

    Dated: August 27, 2018.
Cathy E. Tortorici,
Acting Director, Office of Protected Resources, National Marine 
Fisheries Service.
[FR Doc. 2018-19008 Filed 8-30-18; 8:45 am]
 BILLING CODE 3510-22-P