[Federal Register Volume 86, Number 133 (Thursday, July 15, 2021)]
[Notices]
[Pages 37309-37313]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2021-15047]


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DEPARTMENT OF COMMERCE

National Oceanic and Atmospheric Administration

[RTID 0648-XB222]


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 Shell Offshore 
Inc. (Shell) for the take of marine mammals incidental to geophysical 
survey activity in the Gulf of Mexico.

DATES: The LOA is effective from July 15, 2021, through August 15, 
2021.

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 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

[[Page 37310]]

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

    Shell plans to conduct sea trials of an alternative sound source 
known as the Low Impact Seismic Source-Tuned Pulse Source (LISS-TPS). 
These trials will be conducted using only the LISS-TPS sound source, 
covering portions of approximately 45 lease blocks centered around 
Lease Block AC 690 in Shell's Leopard development area. Please see 
Shell's application for additional detail.
    The LISS-TPS source was not included in the acoustic exposure 
modeling developed in support of 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).
    The LISS-TPS source operates on the same basic principles as a 
traditional airgun source in that it uses compressed air to create a 
bubble in the water column which then goes through a series of 
collapses and expansions creating primarily low-frequency sounds. The 
difference between the two sources is that the LISS-TPS source releases 
a larger volume of air (the LISS-TPS source has a volume of 26,500 
in\3\, whereas the standard airgun array used in the acoustic exposure 
modeling supporting the rule has a total volume of 8,000 in\3\), but at 
lower pressure (the LISS-TPS source operates at 1,000 pounds per square 
inch (psi), whereas traditional airguns are typically operated at 2,000 
psi). This creates a larger bubble resulting in more of the energy 
being concentrated in low-frequencies. The release of the air is also 
``tuned'' so that the primary signal has an extended rise time and 
lower peak pressure level than that of a traditional airgun array 
source.
    The LISS-TPS source produces more sound at lower frequencies 
(approximately 3-7 Hz) compared to an airgun source, while producing 
much less sound (lower decibel levels) at frequencies above 7 Hz, 
meaning that the source produces significantly reduced energy at 
frequencies used by marine mammals for hearing and communication. This 
means that even for species in the low-frequency hearing group 
(mysticete whales) most affected by seismic survey sounds, the LISS-TPS 
source is expected to have less impact than a traditional airgun array 
in terms of overlap with frequencies the species use. Potential impacts 
on mid- and high-frequency hearing groups will be reduced even more.
    Besides producing less energy in frequencies used by marine 
mammals, the LISS-TPS source produces sounds with overall lower energy 
at the source. Test data for the actual source planned for use in these 
trials were obtained at a quarry, showing that the LISS-TPS source 
produces significantly less output than a traditional airgun array at 
all frequencies above 5 Hz. For example, the LISS-TPS source level (at 
the typical reference distance of 1 m) has a peak sound pressure level 
(SPL<INF>peak</INF>) of 236 dB and a single-shot sound exposure level 
(SEL) of 220 dB. These measured levels are 19 dB and 12 dB less than 
the modeled SPL<INF>peak</INF> and SEL source levels, respectively, for 
the 8,000-in\3\ airgun array used in the acoustic exposure modeling 
(source level = 255 dB SPL<INF>peak</INF>; 232 dB SEL). For every 6-dB 
reduction in source level, the approximate distance to the same 
threshold level would be cut in half, meaning that there would be more 
than an 8-fold reduction in distance to SPL<INF>peak</INF> thresholds. 
There would also be a significant reduction in the likelihood that 
auditory injury could result from the accumulation of energy (which is 
expected to dictate occurrence of injury for low-frequency cetaceans, 
though they are not expected to occur in the area of this planned 
survey). The much lower peak sound pressure levels near the source and 
extended rise time reduce the potential for auditory injury (Level A 
harassment) for all marine mammal species, since these are the two main 
physical characteristics of impulsive sounds that are considered most 
injurious.
    The LISS-TPS source produces a 33 dB lower root-mean-square SPL 
(SPL<INF>rms</INF>), compared with estimates for a commonly used 5,110-
in \3\ airgun array. Thus, a reduction in the source level of 33 dB 
would result in distances to SPL<INF>rms</INF> Level B harassment 
thresholds being less than 1/32 of the airgun array. These factors lead 
to a conclusion that take by Level B harassment associated with use of 
the LISS-TPS source would be less than would occur for a similar survey 
instead using the modeled airgun array as a sound source, and that use 
of the LISS-TPS source results in lower potential for the occurrence of 
Level A harassment than does use of the modeled airgun array. Based on 
the foregoing, we have determined there will be no effects of a 
magnitude or intensity different from those evaluated in support of the 
rule. Moreover, use of modeling results relating to use of the 72 
element, 8,000 in \3\ airgun array are expected to be significantly 
conservative as a proxy for use in evaluating potential impacts of use 
of the LISS-TPS source.
    (We also note that for this LISS-TPS source, BOEM determined that 
Endangered Species Act (ESA) section 7 step-down review of the LISS-TPS 
source was required under NMFS' 2020 Biological Opinion on the 
Federally Regulated Oil and Gas Program Activities in the Gulf of 
Mexico. This step-down review was conducted in association with 
modification of BOEM's Permit L20-012. NMFS' ESA Interagency 
Consultation Division requested and received an analysis from BOEM that 
considered the effects associated with the LISS-TPS source. As a result 
of this review, NMFS determined that use of the source is

[[Page 37311]]

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 Shell 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, 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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    3D NAZ was used as the most suitable proxy for survey type based on 
the survey design and similarities to the general 3D NAZ survey 
geometry. Although this planned survey would only use a single source 
vessel, compared with the two source vessels assumed in modeling 3D NAZ 
surveys, the planned line spacing is most comparable to 3D NAZ. Please 
see summary descriptions of modeled survey geometries in the preamble 
to the proposed rule (83 FR 29212, 29220; June 22, 2018). Take numbers 
authorized through the LOA are considered very conservative due to 
differences in both the sound source and the survey geometry planned by 
Shell, as compared to those modeled for the rule.
    The survey is planned to occur for 20 days, with 8 days occurring 
in Zone 6 and 12 days in Zone 7. The season is defined as summer. Note 
that Rice's (formerly Bryde's) whales \3\ are assumed to not be present 
in Zone 6 (see 83 FR 29212, 29253; June 22, 2018), and no take of 
Rice's whale is authorized through this LOA. Note that use of the 
modeling results indicates that no take of Rice's whale would occur in 
Zone 7.
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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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    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 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 
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.
    Killer whales are the most rarely encountered species in the GOM, 
typically in deep waters of the central GOM (Roberts et al., 2015; 
Maze-Foley and Mullin, 2006). The approach used in the acoustic 
exposure modeling, in which seven modeling zones were defined over the 
U.S. GOM, necessarily averages fine-scale information about marine 
mammal distribution over the large area of each modeling zone. NMFS has 
determined that the approach results in unrealistic projections 
regarding the likelihood of encountering killer whales.
    As discussed in the final rule, the density models produced by 
Roberts et al. (2016) provide the best available scientific information 
regarding predicted density patterns of cetaceans in the U.S. GOM. The 
predictions represent the output of models derived from multi-year 
observations and associated environmental parameters that incorporate 
corrections for detection bias. However, in the case of killer whales, 
the model is informed by few data, as indicated by the coefficient of 
variation associated with the abundance predicted by the model (0.41, 
the second-highest of any GOM species model; Roberts et al., 2016). The 
model's authors noted the expected non-uniform distribution of this 
rarely-encountered species (as discussed above) and expressed that, due 
to the limited data available to inform the model, it ``should be 
viewed cautiously'' (Roberts et al., 2015).
    NOAA surveys in the GOM from 1992-2009 reported only 16 sightings 
of killer whales, with an additional three 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 
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 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 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

[[Page 37312]]

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 would 
result in high 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).
    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. 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, 5438; January 19, 2021).
    The take numbers for authorization are determined as described 
above. 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 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 
determination, as depicted in Table 1 for Shell's 20-day survey.
    This product is used by NMFS in making the necessary small numbers 
determination, 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.

                                             Table 1--Take Analysis
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                                                    Authorized      Scaled take                       Percent
                     Species                           take             \1\        Abundance \2\     abundance
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Sperm whale.....................................             347           146.8           2,207             6.7
Kogia spp.......................................         \3\ 107            33.1           4,373             0.8
Beaked whales...................................           1,990           201.0           3,768             5.3
Rough-toothed dolphin...........................             270            77.5           4,853             1.6
Bottlenose dolphin..............................             511           146.7         176,108             0.1
Clymene dolphin.................................           1,001           287.3          11,895             2.4
Atlantic spotted dolphin........................             213            61.1          74,785             0.1
Pantropical spotted dolphin.....................           4,946         1,419.5         102,361             1.4
Spinner dolphin.................................         \4\ 152            43.6          25,114             0.2
Striped dolphin.................................             347            99.6           5,229             1.9
Fraser's dolphin................................             125            35.9           1,665             2.2
Risso's dolphin.................................             180            53.1           3,764             1.4
Melon-headed whale..............................             552           162.8           7,003             2.3
Pygmy killer whale..............................             169            49.9           2,126             2.3
False killer whale..............................             222            65.5           3,204             2.0
Killer whale....................................               7             n/a             267             2.6
Short-finned pilot whale........................             216            63.7           1,981             3.2
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\1\ Scalar ratios were applied to ``Authorized Take'' values as described at 86 FR 5322, 5404 (January 19, 2021)
  to derive scaled take numbers shown here.
\2\ Best abundance estimate. For most taxa, the best abundance estimate for purposes of comparison with take
  estimates is considered here to be the model-predicted abundance (Roberts et al., 2016). For those taxa where
  a density surface model predicting abundance by month was produced, the maximum mean seasonal abundance was
  used. For those taxa where abundance is not predicted by month, only mean annual abundance is available. For
  the killer whale, the larger estimated SAR abundance estimate is used.
\3\ Includes 4 takes by Level A harassment and 103 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.
\4\ Estimated take of 117 increased based on assumed average group size of 152 (Maze-Foley and Mullin, 2006).

    Based on the analysis contained herein of Shell'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.

[[Page 37313]]

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

    Dated: July 12, 2021.
Catherine Marzin,
Acting Director, Office of Protected Resources, National Marine 
Fisheries Service.
[FR Doc. 2021-15047 Filed 7-14-21; 8:45 am]
BILLING CODE 3510-22-P