[Federal Register Volume 88, Number 73 (Monday, April 17, 2023)]
[Notices]
[Pages 23403-23407]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2023-08019]


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DEPARTMENT OF COMMERCE

National Oceanic and Atmospheric Administration

[RTID 0648-XC915]


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 WesternGeco for 
the take of marine mammals incidental to geophysical survey activity in 
the Gulf of Mexico.

DATES: The LOA is effective from April 12, 2023 through April 1, 2024.

ADDRESSES: The LOA, LOA request, and supporting documentation are 
available online at: 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 
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

[[Page 23404]]

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

    WesternGeco plans to conduct a 3D ocean bottom node (OBN) survey in 
the Green Canyon, Garden Banks, and Walker Ridge protraction areas, 
including approximately 616 lease blocks. Approximate water depths of 
the survey area range from 55 to 2,000 meters (m). See section F of the 
LOA application for a map of the area.
    WesternGeco anticipates using two triple source vessels, towing 
airgun array sources consisting of 28 elements, with a total volume of 
5,240 cubic inches (in\3\). Please see WesternGeco's application for 
additional detail.
    Consistent with the preamble to the final rule, the survey effort 
proposed by WesternGeco 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 numbers 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 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 two source 
vessels sailing along survey lines approximately 70-80 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 WesternGeco is not 
proposing to perform a survey using the coil geometry, its planned 3D 
OBN survey is expected to cover approximately 130 km\2\ per day, 
meaning that the coil proxy is most representative of the effort 
planned by WesternGeco in terms of predicted Level B harassment 
exposures.
    In addition, all available acoustic exposure modeling results 
assume use of a 72-element, 8,000 in\3\ array. Thus, estimated take 
numbers for this LOA are considered conservative due to differences 
between the airgun array planned for use (28 elements, 5,240 in\3\) and 
the proxy array modeled for the rule.
    The survey will take place over approximately 85 days, including 65 
days of sound source operation. The survey plan includes approximately 
57 days within Zone 5 and approximately 8 days within Zone 2. The 
seasonal distribution of survey days is not known in advance. 
Therefore, the take estimates for each species are based on the season 
that produces the greater value.
    Additionally, 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. This can result in unrealistic projections 
regarding the likelihood of encountering particularly rare species and/
or species not expected to occur outside particular habitats. Thus, 
although the modeling conducted for the rule is a natural starting 
point for estimating take, our 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 other 
relevant information reviewed during the rulemaking that indicates use 
of the acoustic exposure modeling to

[[Page 23405]]

generate a take estimate for certain marine mammal species produces 
results that are inconsistent with what is known regarding their 
occurrence in the GOM. Accordingly, we have adjusted the calculated 
take estimates for those species as described below.
    Rice's whales (formerly known as GOM Bryde's whales) \3\ are mostly 
found in a ``core habitat area'' located in the northeastern GOM in 
waters between 100-400 m depth along the continental shelf break (Rosel 
et al., 2016). (Note that this core habitat area is outside the scope 
of the rule.) However, whaling records suggest that Rice's whales 
historically had a broader distribution within similar habitat 
parameters throughout the GOM (Reeves et al., 2011; Rosel and Wilcox, 
2014). In addition, habitat-based density modeling identified similar 
habitat (i.e., approximately 100-400 m water depths along the 
continental shelf break) as being potential Rice's whale habitat 
(Roberts et al., 2016), although the core habitat area contained 
approximately 92 percent of the predicted abundance of Rice's whales. 
See discussion provided at, e.g., 83 FR 29228, 83 FR 29280 (June 22, 
2018); 86 FR 5418 (January 19, 2021).
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    \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).
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    There are few data on Rice's whale occurrence outside of the 
northeastern GOM core habitat area. There were two sightings of 
unidentified large baleen whales (recorded as Balaenoptera sp. or 
Bryde's/sei whale) in 1992 in the western GOM during systematic survey 
effort and, more recently, a NOAA survey reported observation of a 
Rice's whale in the western GOM in 2017 (NMFS, 2018). There were five 
potential sightings of Rice's whales by protected species observers 
(PSOs) aboard industry geophysical survey vessels west of New Orleans 
from 2010-2014, all within the 200-400 m isobaths (Rosel et al., 2021). 
In addition, sporadic, year-round recordings of Rice's whale calls were 
made south of Louisiana within approximately the same depth range 
between 2016 and 2017 (Soldevilla et al., 2022).
    Although Rice's whales may occur outside of the core habitat area, 
we expect that any such occurrence would be limited to the narrow band 
of suitable habitat described above (i.e., 100-400 m) and that, based 
on the few available records, these occurrences would be rare. 
WesternGeco's planned activities will overlap this depth range, with 
approximately 19 percent of the area expected to be ensonified by the 
survey above root-mean-squared pressure received levels (RMS SPL) of 
160 dB (referenced to 1 micropascal (re 1 [mu]Pa)) overlapping the 100-
400 m isobaths. Therefore, while we expect take of Rice's whale to be 
unlikely, there is some reasonable potential for take of Rice's whale 
to occur in association with this survey. However, 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 
Rice's whales would result in estimated take numbers that are 
inconsistent with the assumptions made in the rule regarding expected 
Rice's whale take (86 FR 5322, 5403, January 19, 2021).
    Killer whales are the most rarely encountered species in the GOM, 
typically in deep waters (>700 m) of the central GOM (Roberts et al., 
2015; Maze-Foley and Mullin, 2006). 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 
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; www.boem.gov/gommapps). Two other species were also observed on less than 20 
occasions during the 1992-2009 NOAA surveys (Fraser's dolphin and false 
killer whale \4\). 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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    \4\ 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 encounter 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 four killer whales, noting that the 
whales performed 20 times as many dives to 1-30 m 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 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. In addition, as noted above in relation to the general 
take estimation methodology, the assumed proxy source (72-element, 
8,000-in\3\ array) results in a significant overestimate of the actual 
potential for take to occur. NMFS' determination in reflection of the 
information discussed above, which informed the final rule, is that use 
of the generic acoustic exposure modeling results for killer whales for 
this survey

[[Page 23406]]

would 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 
Rice's or 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; 86 FR 29090, May 28, 
2021; 85 FR 55645, September 9, 2020. For the reasons expressed above, 
NMFS determined that a single encounter of Rice's whales or killer 
whales is more likely than the model-generated estimates and has 
authorized take associated with a single group encounter (i.e., up to 2 
animals for Rice's whale and up to 7 animals for killer whales).
    Based on the results of our analysis, NMFS has determined that the 
level of taking authorized through the LOA is consistent with the 
findings made for the total taking allowable under the regulations for 
the affected species or stocks of marine mammals. 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 one 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 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; 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....................................               2             n/a              51             3.9
Sperm whale.....................................           1,499           634.4           2,207            28.7
Kogia spp.......................................         \3\ 567           181.9           4,373             4.8
Beaked whales...................................           6,617           668.3           3,768            17.7
Rough-toothed dolphin...........................           1,261           361.9           4,853             7.5
Bottlenose dolphin..............................          18,214         5,227.5         176,108             3.0
Clymene dolphin.................................           3,202           918.9          11,895             7.7
Atlantic spotted dolphin........................           4,125         1,183.8          74,785             1.6
Pantropical spotted dolphin.....................          14,529         4,170.0         102,361             4.1
Spinner dolphin.................................           3,893         1,117.3          25,114             4.4
Striped dolphin.................................           1,250           358.9           5,229             6.9
Fraser's dolphin................................             363           104.1           1,665             6.3
Risso's dolphin.................................             941           277.6           3,764             7.4
Melon-headed whale..............................           2,104           620.6           7,003             8.9
Pygmy killer whale..............................             495           146.0           2,126             6.9
False killer whale..............................             797           235.0           3,204             7.3
Killer whale....................................               7             n/a             267             2.6
Short-finned pilot whale........................             608           179.5           1,981             9.1
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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 the killer whale, the larger estimated SAR abundance estimate is used.
\3\ Includes 30 takes by Level A harassment and 537 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.

    Based on the analysis contained herein of WesternGeco'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 and 
therefore is of no more than small numbers.

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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 WesternGeco authorizing the take of marine 
mammals incidental to its geophysical survey activity, as described 
above.

    Dated: April 11, 2023.
Kimberly Damon-Randall,
Director, Office of Protected Resources, National Marine Fisheries 
Service.
[FR Doc. 2023-08019 Filed 4-14-23; 8:45 am]
BILLING CODE 3510-22-P