[Federal Register Volume 88, Number 204 (Tuesday, October 24, 2023)]
[Notices]
[Pages 72996-73000]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2023-23455]


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DEPARTMENT OF COMMERCE

National Oceanic and Atmospheric Administration

[RTID 0648-XD470]


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 (GOM), notification is hereby 
given that a Letter of Authorization (LOA) has been issued to Murphy 
Exploration & Production Company (Murphy) for the take of marine 
mammals incidental to geophysical survey activity in the GOM.

DATES: The LOA is effective from November 1, 2023, through October 30, 
2024.

ADDRESSES: The LOA, LOA request, and supporting documentation are 
available online at: https://www.fisheries.noaa.gov/action/incidental-
take-authorization-oil-and-

[[Page 72997]]

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: Rachel Wachtendonk, 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 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 U.S. waters of the 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

    Murphy plans to conduct a vertical seismic profile (VSP) within 
Atwater Valley Block 138. The survey will occur at a water depth of 
1,050 meters (m). Murphy plans to use a 12-element, 2,400 cubic inch 
(in\3\) airgun array. The survey is planned to occur for 2 days during 
the period from November 1, 2023 to October 30, 2024. Please see 
Murphy's application for additional detail.
    Consistent with the preamble to the final rule, the survey effort 
proposed by Murphy 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 5322, 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 VSP surveys were included in the modeled survey types, and use 
of existing proxies (i.e., two-dimensional (2D), three-dimensional 
narrow azimuth (3D NAZ), 3D wide-azimuth (WAZ), Coil) is generally 
conservative for use in evaluation of VSP survey effort. Summary 
descriptions of these modeled survey geometries are available in the 
preamble to the proposed rule (83 FR 29212, June 22, 2018). Coil was 
selected as the best available proxy survey type because the spatial 
coverage of the planned survey is most similar to that associated with 
the coil survey pattern.
    For the planned survey, the seismic source array will be deployed 
from a stationary drilling rig at or near the borehole, with the 
seismic receivers (i.e., geophones) deployed in the borehole on 
wireline at specified depth intervals. The coil survey pattern in the 
model 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. Because Murphy's planned survey would not cover 
any additional area beyond that ensonified by the stationary source, 
the coil proxy is most representative of the effort planned by Murphy 
in terms of predicted Level B harassment.
    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 the differences 
in both the airgun array (12 elements and 2,400 in\3\), and in daily 
survey area planned by Murphy, as compared to those modeled for the 
rule.
    The survey is planned to occur in Zone 5. The survey could take 
place in any season. Therefore, the take estimates for each species are 
based on the season that has the greater value for the species (i.e., 
winter or summer).
    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

[[Page 72998]]

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 5322, 
(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 generate a take 
estimate for Rice's whales and killer whales produces results 
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.
    NMFS' final rule described a ``core habitat area'' for Rice's 
whales (formerly known as GOM Bryde's whales) \3\ located in the 
northeastern GOM in waters between 100-400 m depth along the 
continental shelf break (Rosel et al., 2016). 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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    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. Murphy's 
planned activities will occur in water depths of approximately 1,050 m 
in the central GOM. Thus, NMFS does not expect there to be the 
reasonable potential for take of Rice's whale in association with this 
survey and, accordingly, does not authorize take of Rice's whale 
through the LOA.
    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). 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 2017-2018 (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 \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 5322, 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 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. 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 
will generally result in estimated take numbers that are inconsistent 
with the assumptions made in the rule regarding expected killer whale 
take (86 FR 5322, 86 FR 5403, January 19, 2021). In this case, use of 
the acoustic exposure modeling produces an estimate of one killer whale 
exposure. Given the foregoing, it is unlikely that any killer whales 
would be encountered during this at most 2-day

[[Page 72999]]

survey, and accordingly no take of killer whales is authorized through 
this LOA.
    In addition, in this case, use of the exposure modeling produces 
results that are smaller than average GOM group sizes for one species 
(Maze-Foley and Mullin, 2006). NMFS' typical practice in such a 
situation is to increase exposure estimates to the assumed average 
group size for a species in order to ensure that, if the species is 
encountered, exposures will not exceed the authorized take number. 
However, other relevant considerations here lead to a determination 
that increasing the estimated exposures to the average group size would 
likely lead to an overestimate of actual potential take. In this 
circumstance, the very short survey duration (maximum of 2 days) and 
relatively small Level B harassment isopleths produced through use of 
the 12-element, 2,400-in\3\ airgun array (compared with the modeled 72-
element, 8,000 in\3\ array) mean that it is unlikely that certain 
species would be encountered at all, much less that the encounter would 
result in exposure of a greater number of individuals than is estimated 
through use of the exposure modeling results. As a result, in this case 
NMFS has not increased the estimated exposure values to assumed average 
group sizes in authorizing take.
    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 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 5322, 86 FR 5438, January 19, 2021).
    The take numbers for authorization, which are determined as 
described above, are used by NMFS in making the necessary small numbers 
determinations through comparison with the best available abundance 
estimates (see discussion at 86 FR 5322, 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                        Percent
                             Species                                 take \1\      Abundance \2\     abundance
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Rice's whale....................................................               0              51             n/a
Sperm whale.....................................................              53           2,207             2.4
Kogia spp.......................................................          \3\ 20           4,373             0.4
Beaked whales...................................................             232           3,768             6.2
Rough-toothed dolphin...........................................              40           4,853             0.8
Bottlenose dolphin..............................................             189         176,108             0.1
Clymene dolphin.................................................             112          11,895             0.9
Atlantic spotted dolphin........................................              76          74,785             0.1
Pantropical spotted dolphin.....................................             510         102,361             0.5
Spinner dolphin.................................................         \4\ 137          25,114             0.5
Striped dolphin.................................................          \4\ 44           5,229             0.8
Fraser's dolphin................................................          \4\ 13           1,665             0.8
Risso's dolphin.................................................              33           3,764             0.9
Melon-headed whale..............................................          \4\ 74           7,003             1.1
Pygmy killer whale..............................................          \4\ 17           2,126             0.8
False killer whale..............................................              28           3,204             0.9
Killer whale....................................................               0             267             n/a
Short-finned pilot whale........................................          \4\ 21           1,981             1.1
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\1\ Scalar ratios were not applied in this case due to brief survey duration.
\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\ Includes 1 take by Level A harassment and 19 takes by Level B harassment.
\4\ Modeled exposure estimate less than assumed average group size (Maze-Foley and Mullin, 2006).

    Based on the analysis contained herein of Murphy'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

[[Page 73000]]

amount of take authorized under the LOA is of no more than small 
numbers. Accordingly, we have issued an LOA to Murphy authorizing the 
take of marine mammals incidental to its geophysical survey activity, 
as described above.

    Dated: October 19, 2023.
Kimberly Damon-Randall,
Director, Office of Protected Resources, National Marine Fisheries 
Service.
[FR Doc. 2023-23455 Filed 10-23-23; 8:45 am]
BILLING CODE 3510-22-P