[Federal Register Volume 88, Number 118 (Wednesday, June 21, 2023)]
[Notices]
[Pages 40209-40212]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2023-13195]


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DEPARTMENT OF COMMERCE

National Oceanic and Atmospheric Administration

[RTID 0648-XD091]


Taking and Importing Marine Mammals; Taking Marine Mammals 
Incidental to Geophysical Surveys Related to Oil and Gas Activities in 
the Gulf of Mexico

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

ACTION: Notice of issuance of Letter of Authorization.

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SUMMARY: In accordance with the Marine Mammal Protection Act (MMPA), as 
amended, its implementing regulations, and NMFS' MMPA Regulations for 
Taking Marine Mammals Incidental to Geophysical Surveys Related to Oil 
and Gas Activities in the Gulf of Mexico, notification is hereby given 
that a Letter of Authorization (LOA) has been issued to Chevron U.S.A. 
Inc. (Chevron) for the take of marine mammals incidental to geophysical 
survey activity in the Gulf of Mexico.

DATES: The LOA is effective from August 10, 2023, through January 2, 
2024.

ADDRESSES: The LOA, LOA request, and supporting documentation are 
available online at: https://www.fisheries.noaa.gov/action/incidental-take-authorization-oil-and-gas-industry-geophysical-survey-activity-gulf-mexico. In case of problems accessing these documents, please call 
the contact listed below (see FOR FURTHER INFORMATION CONTACT).

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

SUPPLEMENTARY INFORMATION: 

Background

    Sections 101(a)(5)(A) and (D) of the MMPA (16 U.S.C. 1361 et seq.) 
direct the Secretary of Commerce 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

[[Page 40210]]

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 authorization is 
provided to the public for review.
    An authorization for incidental takings shall be granted if NMFS 
finds that the taking will have a negligible impact on the species or 
stock(s), will not have an unmitigable adverse impact on the 
availability of the species or stock(s) for subsistence uses (where 
relevant), and if the permissible methods of taking and requirements 
pertaining to the mitigation, monitoring and reporting of such takings 
are set forth. NMFS has defined ``negligible impact'' in 50 CFR 216.103 
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.
    Except with respect to certain activities not pertinent here, 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).
    On January 19, 2021, we issued a final rule with regulations to 
govern the unintentional taking of marine mammals incidental to 
geophysical survey activities conducted by oil and gas industry 
operators, and those persons authorized to conduct activities on their 
behalf (collectively ``industry operators''), in Federal waters of the 
U.S. Gulf of Mexico (GOM) over the course of 5 years (86 FR 5322, 
January 19, 2021). The rule was based on our findings that the total 
taking from the specified activities over the 5-year period will have a 
negligible impact on the affected species or stock(s) of marine mammals 
and will not have an unmitigable adverse impact on the availability of 
those species or stocks for subsistence uses. The rule became effective 
on April 19, 2021.
    Our regulations at 50 CFR 217.180 et seq. allow for the issuance of 
LOAs to industry operators for the incidental take of marine mammals 
during geophysical survey activities and prescribe the permissible 
methods of taking and other means of effecting the least practicable 
adverse impact on marine mammal species or stocks and their habitat 
(often referred to as mitigation), as well as requirements pertaining 
to the monitoring and reporting of such taking. Under 50 CFR 
217.186(e), issuance of an LOA shall be based on a determination that 
the level of taking will be consistent with the findings made for the 
total taking allowable under these regulations and a determination that 
the amount of take authorized under the LOA is of no more than small 
numbers.

Summary of Request and Analysis

    Chevron plans to conduct a 3D ocean bottom node (OBN) survey over 
Walker Ridge Lease Blocks 758, 759, and 802, and the surrounding 
approximately 90 lease blocks, with approximate water depths ranging 
from approximately 2,000 to 2,400 meters (m). See Chevron's LOA 
application for a map of the area. Chevron anticipates using a single 
dual source vessel, towing airgun array sources consisting of 42 
elements, with a total volume of 5,380 cubic inches (in\3\). Please see 
Chevron's application for additional detail.
    Consistent with the preamble to the final rule, the survey effort 
proposed by Chevron in its LOA request was used to develop LOA-specific 
take estimates based on the acoustic exposure modeling results 
described in the preamble (86 FR 5398, January 19, 2021). In order to 
generate the appropriate take number for authorization, the following 
information was considered: (1) survey type; (2) location (by modeling 
zone); \1\ (3) number of days; and (4) season.\2\ The acoustic exposure 
modeling performed in support of the rule provides 24-hour exposure 
estimates for each species, specific to each modeled survey type in 
each zone and season.
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    \1\ For purposes of acoustic exposure modeling, the GOM was 
divided into seven zones. Zone 1 is not included in the geographic 
scope of the rule.
    \2\ For purposes of acoustic exposure modeling, seasons include 
Winter (December-March) and Summer (April-November).
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    No 3D OBN surveys were included in the modeled survey types, and 
use of existing proxies (i.e., 2D, 3D NAZ, 3D WAZ, Coil) is generally 
conservative for use in evaluation of 3D OBN survey effort, largely due 
to the greater area covered by the modeled proxies. Summary 
descriptions of these modeled survey geometries are available in the 
preamble to the proposed rule (83 FR 29212, 29220, June 22, 2018). Coil 
was selected as the best available proxy survey type in this case 
because the spatial coverage of the planned survey is most similar to 
the coil survey pattern. The planned 3D OBN survey will involve a 
single source vessel sailing along closely spaced survey lines that are 
approximately 100-150 m apart and approximately 40 kilometers (km) in 
length. The coil survey pattern was assumed to cover approximately 144 
kilometers squared (km\2\) per day (compared with approximately 795 
km\2\, 199 km\2\, and 845 km\2\ per day for the 2D, 3D NAZ, and 3D WAZ 
survey patterns, respectively). Among the different parameters of the 
modeled survey patterns (e.g., area covered, line spacing, number of 
sources, shot interval, total simulated pulses), NMFS considers area 
covered per day to be most influential on daily modeled exposures 
exceeding Level B harassment criteria. Although Chevron is not 
proposing to perform a survey using the coil geometry, its planned 3D 
OBN survey is expected to cover approximately 10 km\2\ per day, meaning 
that the coil proxy is most representative of the effort planned by 
Chevron in terms of predicted Level B harassment exposures.
    All available acoustic exposure modeling results assume use of a 
72-element, 8,000 in\3\ array. Thus, take numbers authorized through 
the LOA are considered conservative due to differences in the airgun 
array (43 elements, 5,380 in\3\), as compared to the source modeled for 
the rule.
    The survey will take place over approximately 90 days, including 75 
days of sound source operation. The entire survey would occur within 
Zone 7. Chevron plans to conduct 25 survey days in the ``Summer'' 
season and 50 days in the ``Winter'' season.
    For some species, take estimates based solely on the modeling 
yielded results that are not realistically likely to occur when 
considered in light of other relevant information available during the 
rulemaking process regarding marine mammal occurrence in the GOM. The 
approach used in the acoustic exposure modeling, in which seven 
modeling zones were defined over the U.S. GOM, necessarily averages 
fine-scale information about marine mammal distribution over the large 
area of each modeling zone. Thus, although the modeling conducted for 
the rule is a natural starting point for estimating take, the rule 
acknowledged that other information could be considered (see, e.g., 86 
FR 5442, January 19, 2021), discussing the need to provide flexibility 
and make efficient use of previous public and agency review of other 
information and identifying that additional public review is not 
necessary unless the model or inputs used differ substantively from 
those that were previously reviewed by NMFS and the public. For this 
survey, NMFS has

[[Page 40211]]

other relevant information reviewed during the rulemaking that 
indicates use of the acoustic exposure modeling to generate a take 
estimate for one marine mammal species produces results inconsistent 
with what is known regarding its occurrence in the GOM. Accordingly, we 
have adjusted the calculated take estimates for the species as 
described below.
    Killer whales are the most rarely encountered species in the GOM, 
typically in deep waters of the central GOM (Roberts et al., 2015; 
Maze-Foley and Mullin, 2006). The approach used in the acoustic 
exposure modeling, in which seven modeling zones were defined over the 
U.S. GOM, necessarily averages fine-scale information about marine 
mammal distribution over the large area of each modeling zone. NMFS has 
determined that the approach results in unrealistic projections 
regarding the likelihood of encountering killer whales.
    As discussed in the final rule, the density models produced by 
Roberts et al. (2016) provide the best available scientific information 
regarding predicted density patterns of cetaceans in the U.S. GOM. The 
predictions represent the output of models derived from multi-year 
observations and associated environmental parameters that incorporate 
corrections for detection bias. However, in the case of killer whales, 
the model is informed by few data, as indicated by the coefficient of 
variation associated with the abundance predicted by the model (0.41, 
the second-highest of any GOM species model; Roberts et al., 2016). The 
model's authors noted the expected non-uniform distribution of this 
rarely-encountered species (as discussed above) and expressed that, due 
to the limited data available to inform the model, it ``should be 
viewed cautiously'' (Roberts et al., 2015).
    NOAA surveys in the GOM from 1992-2009 reported only 16 sightings 
of killer whales, with an additional 3 encounters during more recent 
survey effort from 2017-18 (Waring et al., 2013; https://www.boem.gov/gommapps). Two other species were also observed on fewer than 20 
occasions during the 1992-2009 NOAA surveys (Fraser's dolphin and false 
killer whale).\3\ However, observational data collected by protected 
species observers (PSOs) on industry geophysical survey vessels from 
2002-2015 distinguish the killer whale in terms of rarity. During this 
period, killer whales were encountered on only 10 occasions, whereas 
the next most rarely encountered species (Fraser's dolphin) was 
recorded on 69 occasions (Barkaszi and Kelly, 2019). The false killer 
whale and pygmy killer whale were the next most rarely encountered 
species, with 110 records each. The killer whale was the species with 
the lowest detection frequency during each period over which PSO data 
were synthesized (2002-2008 and 2009-2015). This information 
qualitatively informed our rulemaking process, as discussed at 86 FR 
5334 (January 19, 2021), and similarly informs our analysis here.
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    \3\ However, note that these species have been observed over a 
greater range of water depths in the GOM than have killer whales.
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    The rarity of encounters during seismic surveys is not likely to be 
the product of high bias on the probability of detection. Unlike 
certain cryptic species with high detection bias, such as Kogia spp. or 
beaked whales, or deep-diving species with high availability bias, such 
as beaked whales or sperm whales, killer whales are typically available 
for detection when present and are easily observed. Roberts et al. 
(2015) stated that availability is not a major factor affecting 
detectability of killer whales from shipboard surveys, as they are not 
a particularly long-diving species. Baird et al. (2005) reported that 
mean dive durations for 41 fish-eating killer whales for dives greater 
than or equal to 1 minute in duration was 2.3-2.4 minutes, and Hooker 
et al. (2012) reported that killer whales spent 78 percent of their 
time at depths between 0-10 m. Similarly, Kvadsheim et al. (2012) 
reported data from a study of 4 killer whales, noting that the whales 
performed 20 times as many dives 1-30 m in depth than to deeper waters, 
with an average depth during those most common dives of approximately 3 
m.
    In summary, killer whales are the most rarely encountered species 
in the GOM and typically occur only in particularly deep water (>700 
m). This survey would take place in deep waters that would overlap with 
depths in which killer whales typically occur. While this information 
is reflected through the density model informing the acoustic exposure 
modeling results, there is relatively high uncertainty associated with 
the model for this species, and the acoustic exposure modeling applies 
mean distribution data over areas where the species is in fact less 
likely to occur. NMFS' determination in reflection of the data 
discussed above, which informed the final rule, is that use of the 
generic acoustic exposure modeling results for killer whales will 
generally result in estimated take numbers that are inconsistent with 
the assumptions made in the rule regarding expected killer whale take 
(86 FR 5403, January 19, 2021).
    In past authorizations, NMFS has often addressed situations 
involving the low likelihood of encountering a rare species, such as 
killer whales in the GOM, through authorization of take of a single 
group of average size (i.e., representing a single potential 
encounter). See 83 FR 63268, December 7, 2018. See also 86 FR 29090, 
May 28, 2021 and 85 FR 55645, September 9, 2020. For the reasons 
expressed above, NMFS determined that a single encounter of killer 
whales is more likely than the model-generated estimates and has 
authorized take associated with a single group encounter (i.e., up to 
seven animals).
    Based on the results of our analysis, NMFS has determined that the 
level of taking expected for this survey and authorized through the LOA 
is consistent with the findings made for the total taking allowable 
under the regulations. See Table 1 in this notice and Table 9 of the 
rule (86 FR 5322, January 19, 2021).

Small Numbers Determination

    Under the GOM rule, NMFS may not authorize incidental take of 
marine mammals in an LOA if it will exceed ``small numbers.'' In short, 
when an acceptable estimate of the individual marine mammals taken is 
available, if the estimated number of individual animals taken is up 
to, but not greater than, one-third of the best available abundance 
estimate, NMFS will determine that the numbers of marine mammals taken 
of a species or stock are small. For more information please see NMFS' 
discussion of the MMPA's small numbers requirement provided in the 
final rule (86 FR 5438, January 19, 2021).
    The take numbers for authorization are determined as described 
above in the Summary of Request and Analysis section. Subsequently, the 
total incidents of harassment for each species are multiplied by scalar 
ratios to produce a derived product that better reflects the number of 
individuals likely to be taken within a survey (as compared to the 
total number of instances of take), accounting for the likelihood that 
some individual marine mammals may be taken on more than 1 day (see 86 
FR 5404, January 19, 2021). The output of this scaling, where 
appropriate, is incorporated into adjusted total take estimates that 
are the basis for NMFS' small numbers determinations, as depicted in 
Table 1.
    This product is used by NMFS in making the necessary small numbers 
determinations through comparison

[[Page 40212]]

with the best available abundance estimates (see discussion at 86 FR 
5391, January 19, 2021). For this comparison, NMFS' approach is to use 
the maximum theoretical population, determined through review of 
current stock assessment reports (SAR; https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessments) and 
model-predicted abundance information (https://seamap.env.duke.edu/models/Duke/GOM/). For the latter, for taxa where a density surface 
model could be produced, we use the maximum mean seasonal (i.e., 3-
month) abundance prediction for purposes of comparison as a 
precautionary smoothing of month-to-month fluctuations and in 
consideration of a corresponding lack of data in the literature 
regarding seasonal distribution of marine mammals in the GOM. 
Information supporting the small numbers determinations is provided in 
Table 1.

                                             Table 1--Take Analysis
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                                                    Authorized      Scaled take                       Percent
                     Species                           take             \1\        Abundance \2\     abundance
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Rice's whale \3\................................               0             n/a              51             n/a
Sperm whale.....................................             371           156.9           2,207             7.1
Kogia spp.......................................         \4\ 206            60.0           4,373             1.8
Beaked whales...................................           3,338           337.2           3,768             8.9
Rough-toothed dolphin...........................             590           169.3           4,853             3.5
Bottlenose dolphin..............................          \5\ 21             6.0         176,108             0.0
Clymene dolphin.................................           1,533           439.9          11,895             3.7
Atlantic spotted dolphin........................               0             n/a          74,785             n/a
Pantropical spotted dolphin.....................          15,216         4,366.9         102,361             4.3
Spinner dolphin.................................             357           102.5          25,114             0.4
Striped dolphin.................................             796           228.5           5,229             4.4
Fraser's dolphin................................             257            73.8           1,665             4.4
Risso's dolphin.................................             252            74.3           3,764             2.0
Melon-headed whale..............................           1,014           299.3           7,003             4.3
Pygmy killer whale..............................             488           144.0           2,126             6.8
False killer whale..............................             553           163.0           3,204             5.1
Killer whale....................................               7             n/a             267             2.6
Short-finned pilot whale........................              80            23.7           1,981             1.2
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\1\ Scalar ratios were applied to ``Authorized Take'' values as described at 86 FR 5322, 5404 (January 19, 2021)
  to derive scaled take numbers shown here.
\2\ Best abundance estimate. For most taxa, the best abundance estimate for purposes of comparison with take
  estimates is considered here to be the model-predicted abundance (Roberts et al., 2016). For those taxa where
  a density surface model predicting abundance by month was produced, the maximum mean seasonal abundance was
  used. For those taxa where abundance is not predicted by month, only mean annual abundance is available. For
  Rice's whale and killer whale, the larger estimated SAR abundance estimate is used.
\3\ The final rule refers to the GOM Bryde's whale (Balaenoptera edeni). These whales were subsequently
  described as a new species, Rice's whale (Balaenoptera ricei) (Rosel et al., 2021).
\4\ Includes 19 takes by Level A harassment and 187 takes by Level B harassment. Scalar ratio is applied to
  takes by Level B harassment only; small numbers determination made on basis of scaled Level B harassment take
  plus authorized Level A harassment take.
\5\ Modeled take of 16 increased to account for potential encounter with group of average size (Maze-Foley and
  Mullin, 2006).

    Based on the analysis contained herein of Chevron's proposed survey 
activity described in its LOA application and the anticipated take of 
marine mammals, NMFS finds that small numbers of marine mammals will be 
taken relative to the affected species or stock sizes (i.e., less than 
one-third of the best available abundance estimate) and therefore the 
taking is of no more than small numbers.

Authorization

    NMFS has determined that the level of taking for this LOA request 
is consistent with the findings made for the total taking allowable 
under the incidental take regulations and that the amount of take 
authorized under the LOA is of no more than small numbers. Accordingly, 
we have issued an LOA to Chevron authorizing the take of marine mammals 
incidental to its geophysical survey activity, as described above.

    Dated: June 15, 2023.
Kimberly Damon-Randall,
Director, Office of Protected Resources, National Marine Fisheries 
Service.
[FR Doc. 2023-13195 Filed 6-20-23; 8:45 am]
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