[Federal Register Volume 89, Number 59 (Tuesday, March 26, 2024)]
[Notices]
[Pages 20946-20949]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2024-06307]


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DEPARTMENT OF COMMERCE

National Oceanic and Atmospheric Administration

[RTID 0648-XD615]


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 Murphy 
Exploration and Production Company (Murphy) for the take of marine 
mammals incidental to geophysical survey activity in the Gulf of 
Mexico.

DATES: The LOA is effective from April 1, 2024 through October 31, 
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: Jenna Harlacher, 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

[[Page 20947]]

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 
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 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 three-dimensional (3D) ocean bottom node 
(OBN) survey in the Green Canyon protraction area, including 
approximately 44 lease blocks. Approximate water depths of the survey 
area range from 914 to 3,372 meters (m). See section F of the LOA 
application for a map of the area.
    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 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 to March) and summer (April to November).
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    No 3D OBN surveys were included in the modeled survey types, and 
use of existing proxies (i.e., two-dimensional (2D), 3D narrow-azimuth 
(NAZ), 3D wide-azimuth (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 one source vessel. 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 Murphy is not proposing to perform a 
survey using the coil geometry, its planned 3D OBN survey is expected 
to cover approximately 25.6 km\2\ per day, meaning that the coil proxy 
is most representative of the effort planned by Murphy in terms of 
predicted Level B harassment exposures. In addition, all available 
acoustic exposure modeling results assume use of a 72-element, 8,000 
cubic inch (in\3\) array. Thus, as discussed above, estimated take 
numbers for this LOA are considered conservative due to differences in 
both the airgun array (28-element, 5,230 in\3\) and daily survey area 
planned by Murphy, as compared to those modeled for the rule.
    The survey will take place over approximately 44 days, including 40 
days of sound source operation, with all 40 days within Zone 5. 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.
    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 (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

[[Page 20948]]

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 and 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 has identified similar habitat (i.e., approximately 100 to 400 
m water depths along the continental shelf break) as being potential 
Rice's whale habitat (Roberts et al., 2016; Garrison et al., 2023), and 
Rice's whales have been detected within this depth band throughout the 
GOM (Soldevilla et al., 2022, 2024). See discussion provided at, e.g., 
83 FR 29228, June 22, 2018; 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 to 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 
914 to 3,372 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 this 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) 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 to 2009 reported only 16 
sightings of killer whales, with an additional 3 encounters during more 
recent survey effort from 2017 to 2018 (Waring et al., 2013; https://www.boem.gov/gommapps). Two other species were also observed on fewer 
than 20 occasions during the 1992 to 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 to 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 (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 to 2008 and 2009 to 2015). This 
information qualitatively informed our rulemaking process, as discussed 
at 86 FR 5322 and 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 to 2.4 minutes, and 
Hooker et al. (2012) reported that killer whales spent 78 percent of 
their time at depths between 0 and 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 to 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, January 19, 2021; 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; 86 FR 29090, May 28, 
2021; 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 7 animals).
    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

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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 with the best available abundance 
estimates (see discussion at 86 FR 5322, January 19, 2021; 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-assessment-reports-species-stock) 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....................................               0             n/a              51               0
Sperm whale.....................................           1,052             445           2,207            20.2
Kogia spp.......................................         \3\ 398             121           4,373             3.2
Beaked whales...................................           4,644             469           3,768            12.4
Rough-toothed dolphin...........................             798             229           4,853             4.7
Bottlenose dolphin..............................           3,783           1,086         176,108             0.6
Clymene dolphin.................................           2,247             645          11,895             5.4
Atlantic spotted dolphin........................           1,511             434          74,785             0.6
Pantropical spotted dolphin.....................          10,196           2,926         102,361             2.9
Spinner dolphin.................................           2,732             784          25,114             3.1
Striped dolphin.................................             878             252           5,229             4.8
Fraser's dolphin................................             252              72           1,665             4.3
Risso's dolphin.................................             660             195           3,764             5.2
Melon-headed whale..............................           1,476             435           7,003             6.2
Pygmy killer whale..............................             347             102           2,126             4.8
False killer whale..............................             553             163           3,204             5.1
Killer whale....................................               7             n/a             267             2.6
Short-finned pilot whale........................             427             126           1,981             6.4
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\1\ Scalar ratios were applied to ``Authorized Take'' values as described at 86 FR 5322 and 86 FR 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 21 takes by Level A harassment and 377 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 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 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: March 20, 2024.
Kimberly Damon-Randall,
Director, Office of Protected Resources, National Marine Fisheries 
Service.
[FR Doc. 2024-06307 Filed 3-25-24; 8:45 am]
BILLING CODE 3510-22-P