[Federal Register Volume 86, Number 192 (Thursday, October 7, 2021)]
[Notices]
[Pages 55821-55825]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2021-21935]


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DEPARTMENT OF COMMERCE

National Oceanic and Atmospheric Administration

[RTID 0648-XB404]


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 Letters 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 three Letters of Authorization (LOA) have been issued to bp 
Exploration & Production Inc. (bp) for the take of marine mammals 
incidental to geophysical survey activity in the Gulf of Mexico.

DATES: The LOAs are effective from January 1, 2022, through December 
31, 2022.

ADDRESSES: The LOAs, LOA requests, 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

[[Page 55822]]

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

    Bp plans to conduct three separate geophysical surveys, and 
submitted an LOA request for each survey. Each survey is a 3D ocean 
bottom node (OBN) survey within a distinct bp prospect area. The 
surveys will occur within bp's Atlantis, Mad Dog, and Puma prospect 
areas, respectively. See Table 1 and Figure 1 of the respective LOA 
applications for more information regarding the location of these 
areas.
    For each survey, bp anticipates using an airgun array consisting of 
32 elements, with a total volume of 5,110 cubic inches (in\3\). Please 
see bp's applications for additional detail.
    In addition to the previously described conventional airgun source 
arrays, bp would also use a proprietary low-frequency source 
(``Wolfspar'') to supplement the quantity and quality of data collected 
during each survey. The Wolfspar source was not evaluated through the 
rule. However, our rule anticipated the possibility of new and unusual 
technologies (NUT) and determined they would be evaluated on a case-by 
case basis (86 FR 5322, 5442; January 19, 2021). In this case, as 
described below, our evaluation of the source leads to a conclusion 
that no take of marine mammals is likely to occur as a result of the 
source's use and, therefore, no additional review is necessary.
    Wolfspar is a variable-frequency marine resonator that was 
developed to image subsurface features that are challenging to 
penetrate with other seismic sound sources. This source is designed to 
produce ultra-low frequency (from 1.4-16 Hz, but typically used to 
produce signals at 2-4 Hz) swept (non-impulsive) signals, and is used 
in tandem with conventional airgun acoustic sources. The Wolfspar 
source is towed at greater depth than conventional airgun sources (30-
60 m compared with approximately 8-12 m). The system was tested in 
controlled environments in 2013-14, and an open-water system 
integration test was conducted in the GOM in 2014. Field trials were 
conducted in 2017-18. The Wolfspar source has since been used 
consistently in association with bp's survey operations.
    Wolfspar signal duration is tens of seconds, however, the total 
output of the Wolfspar source is less compared to the output of a 
typical large airgun array (1/1000th peak SPL; Dellinger et al., 2016). 
Results of a sound source verification study conducted during the 2017-
18 at-sea trials showed that (1) Wolfspar signals were consistently 
lower in amplitude than signals from the airgun array used in 
conjunction with Wolfspar, with frequency content mostly outside marine 
mammal hearing range, including their most susceptible hearing range 
for noise-induced hearing loss, and (2) signal amplitude was low enough 
that the Wolfspar source was often not detectable above background 
sound levels. Measured 12-second sound exposure level weighted for low-
frequency cetaceans did not exceed 95 dB SEL (source level back-
calculated assuming spherical spreading). The source produces harmonics 
(beyond the fundamental frequency of less than 17 Hz) of decreasing 
spectral amplitude up to 100 Hz. However, harmonics are at lower 
energy, and at higher frequencies (above the fundamental frequency) the 
dominant noise source is not the device itself, but the hydraulic power 
unit and the ship towing the device (absent concurrent use of 
conventional airgun sources). For reference, the hypothesized 
generalized hearing range of low-frequency cetaceans starts at 7 Hz, 
while those of mid- and high-frequency cetaceans are much higher (150 
and 275 Hz, respectively), and the point of greatest sensitivity (i.e., 
greatest susceptibility to noise-induced hearing loss) for these three 
groups is 1.7, 24, and 42 kHz, respectively. Therefore, marine mammals 
may not even detect the Wolfspar signals, much less suffer any 
consequences from exposure.
    Because the source levels are lower than those of concurrently used 
airgun sources, and the frequency content of the signals is 
predominantly outside the hearing range of any marine mammal, NMFS 
concludes that use of the Wolfspar source presents no potential for 
impacts to marine mammals additional to those caused through use of the 
airgun array. Even absent concurrent airgun use, effects to marine 
mammals from the Wolfspar source are unlikely. Due to the signal 
characteristics of the sound source, i.e., slow rise time and 
relatively low source levels, there is no potential for injury of 
marine mammals unless they occur at very close distances to the source 
(<10 m) for a prolonged continuous time period (i.e., implausible 
circumstances). Broadband sounds produced by the vessel towing the 
Wolfspar source are expected to dominate the perceived soundscape 
(absent concurrent airgun use), masking sounds from Wolfspar at 
frequencies audible to marine mammals. NMFS considers impacts to marine 
mammals in association with use of the Wolfspar source to be 
discountable.

[[Page 55823]]

    We also note that Wolfspar was assessed in 2017 as a NUT as part of 
BOEM Permit L17-011 Mod 2, and accordingly underwent Endangered Species 
Act (ESA) section 7 step-down review at that time. Subsequently, 
Wolfspar was again evaluated as a NUT and evaluated through step-down 
review under NMFS' 2020 Biological Opinion on the Federally Regulated 
Oil and Gas Program Activities in the Gulf of Mexico in association 
with BOEM Permit L20-026. As a result of this review, NMFS determined 
that use of the source is unlikely to result in additional effects 
beyond those previously considered in the 2020 Biological Opinion.
    Consistent with the preamble to the final rule, the survey effort 
proposed by bp in its LOA requests was used to develop LOA-specific 
take estimates based on the acoustic exposure modeling results 
described in the preamble (86 FR 5322, 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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    Summary descriptions of the modeled survey geometries (i.e., 2D, 3D 
NAZ, 3D WAZ, Coil) are available in the preamble to the proposed rule 
(83 FR 29212, 29220; June 22, 2018). 3D NAZ was selected as the best 
available proxy survey type. The OBN surveys will employ bottom-mounted 
receivers, or ``nodes,'' used in conjunction with a vessel-towed 
seismic source array. For each survey, bp will deploy up to 4,000 nodes 
which, when fully deployed, will cover approximately 400 km\2\ of 
seafloor for a survey that covers an approximate sea surface area of 
1,200 km\2\. Two dual- or triple-source vessels will be used to produce 
acoustic pulses at regular spatial intervals across the node grid. The 
source vessels will survey along transect lines that extend through, 
and 10 km beyond, the node grid on each site. Note that all available 
acoustic exposure modeling results assume use of a 72-element, 8,000 
in\3\ array. In this case, take numbers authorized through the LOAs are 
considered conservative (i.e., they likely overestimate take) primarily 
due to differences in the airgun arrays planned for use by bp as 
compared to the array modeled for the rule.
    Each survey will take place for up to 50 days. Each of the prospect 
areas is located in the central GOM, roughly on the boundary of Zones 5 
and 7. For each survey, it is assumed that 75 percent would occur in 
Zone 5 and 25 percent in Zone 7. The described distribution was 
selected based on the location of the prospect areas (the majority of 
total prospect area coverage is in Zone 5, with some overlap into Zone 
7). The season is not known in advance. 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). Because all three surveys are the 
same in terms of location (i.e., within the same zones), duration, and 
survey type, the following discussion and resulting take analysis in 
Table 1 below apply to each survey.
    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. 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, 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 these surveys, NMFS has other 
relevant information reviewed during the rulemaking that indicates use 
of the acoustic exposure modeling to generate a take estimate for 
certain marine mammal species produces results inconsistent with what 
is known regarding their occurrence in the GOM. Accordingly, we have 
adjusted the calculated take estimates as described below.
    Rice's whales (formerly known as GOM Bryde's whales) \3\ are 
generally found within a small area in the northeastern GOM in waters 
between 100-400 meters (m) depth along the continental shelf break 
(Rosel et al., 2016). 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), and a NOAA survey reported observation of a Rice's whale in the 
western GOM in 2017 (NMFS, 2018). 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 a ``core habitat area'' 
defined in the northeastern GOM (outside the scope of the rule) 
contained approximately 92 percent of the predicted abundance of Rice's 
whales. See discussion provided at, e.g., 83 FR 29212, 29228, 29280 
(June 22, 2018); 86 FR 5322, 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 it is possible that Rice's whales may occur outside of 
their core habitat, NMFS expects that any such occurrence would be 
limited to the narrow band of suitable habitat described above (i.e., 
100-400 m). Bp's planned activity will occur in water depths of 
approximately 1,200-2,300 m in the central GOM. Based on that 
information, NMFS does not expect there to be the reasonable potential 
for take of Rice's whale in association with these surveys and, 
accordingly, does not authorize take of Rice's whale through these 
LOAs.
    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

[[Page 55824]]

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; 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, 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 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. 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 5322, 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; 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 killer whale group encounter (i.e., up to 7 
animals) for each LOA.
    Based on the results of our analysis, NMFS has determined that the 
level of taking expected for each of these surveys and authorized 
through the LOAs is consistent with the findings made for the total 
taking allowable under the regulations. See Table 1 in this document 
and Table 9 of the final rule (86 FR 5322; January 19, 2021).

Small Numbers Determinations

    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, 5438; January 19, 2021).
    The take numbers for each authorization are determined as described 
above. Subsequently, the total incidents of harassment for each species 
may be 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 5322, 5404; January 19, 2021). 
The output of this scaling, where appropriate, is incorporated into an 
adjusted total take estimate that is 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, 5391; January 19, 2021). For 
this comparison, NMFS' approach is to use the maximum theoretical 
population, determined through review of current stock abundance 
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., three-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. (Note that, because take numbers for each of the 
three surveys are the same, the small numbers analysis applies to each 
survey).

[[Page 55825]]



                                      Table 1--Take Analysis per Survey/LOA
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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             n/a
Sperm whale.....................................           1,712           724.1           2,207            32.8
Kogia spp.......................................         \3\ 635           215.4           4,373             4.9
Beaked whales...................................           8,404           848.8           3,768            22.5
Rough-toothed dolphin...........................           1,208           346.8           4,853             7.1
Bottlenose dolphin..............................           5,689         1,632.9         176,108             0.9
Clymene dolphin.................................           3,823         1,097.3          11,895             9.2
Atlantic spotted dolphin........................           2,205           632.8          74,785             0.8
Pantropical spotted dolphin.....................          19,751         5,668.4         102,361             5.5
Spinner dolphin.................................           4,211         1,208.6          25,114             4.8
Striped dolphin.................................           1,551           445.0           5,229             8.5
Fraser's dolphin................................             448           128.5           1,665             7.7
Risso's dolphin.................................           1,089           321.3           3,764             8.5
Melon-headed whale..............................           2,467           727.8           7,003            10.4
Pygmy killer whale..............................             582           171.6           2,126             8.1
False killer whale..............................             871           257.0           3,204               8
Killer whale....................................               7             n/a             267             2.6
Short-finned pilot whale........................             648           191.1           1,981             9.6
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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 17 takes by Level A harassment and 618 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 Level A harassment take.

    Based on the analysis contained herein of bp's proposed survey 
activity described in its LOA applications and the anticipated take of 
marine mammals, NMFS finds that for each issued LOA 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 these LOA requests 
is consistent with the findings made for the total taking allowable 
under the incidental take regulations and that the amount of take 
authorized under each of the LOAs is of no more than small numbers. 
Accordingly, we have issued three LOAs to bp authorizing the take of 
marine mammals incidental to its geophysical survey activity, as 
described above.

Kimberly Damon-Randall,
Director, Office of Protected Resources, National Marine Fisheries 
Service.
[FR Doc. 2021-21935 Filed 10-6-21; 8:45 am]
BILLING CODE 3510-22-P