[Federal Register Volume 88, Number 3 (Thursday, January 5, 2023)]
[Proposed Rules]
[Pages 916-948]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2022-28208]



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Vol. 88

Thursday,

No. 3

January 5, 2023

Part II





 Department of Commerce





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 National Oceanic and Atmospheric Administration





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50 CFR Part 217





Taking and Importing Marine Mammals; Taking Marine Mammals Incidental 
to Geophysical Surveys in the Gulf of Mexico; Proposed Rule

  Federal Register / Vol. 88 , No. 3 / Thursday, January 5, 2023 / 
Proposed Rules  

[[Page 916]]


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DEPARTMENT OF COMMERCE

National Oceanic and Atmospheric Administration

50 CFR Part 217

[Docket No. 221221-0280]
RIN 0648-BL68


Taking and Importing Marine Mammals; Taking Marine Mammals 
Incidental to Geophysical Surveys in the Gulf of Mexico

AGENCY: National Marine Fisheries Service (NMFS), National Oceanic and 
Atmospheric Administration (NOAA), Commerce.

ACTION: Proposed rule; request for comments.

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SUMMARY: NMFS is reassessing the statutorily mandated findings 
supporting its January 19, 2021, final rule and Regulations Governing 
Taking Marine Mammals Incidental to Geophysical Survey Activities in 
the Gulf of Mexico issued pursuant to the Marine Mammal Protection Act 
(MMPA), in light of updated information following the discovery that 
the estimates of incidental take of marine mammals anticipated from the 
activities analyzed for the 2021 regulations were erroneous. The 
correction of this error, as well as other newly available and 
pertinent information, has bearing on the analyses supporting some of 
the prior findings in the 2021 final rule and the taking allowable 
under the regulations. There are no changes to the specified activities 
or the specified geographical region in which those activities would be 
conducted, nor to the original 5-year period of effectiveness. Here, in 
light of the new information, NMFS presents new ``negligible impact'' 
analyses supporting our preliminary affirmance of the negligible impact 
determinations for all species, and proposes to affirm that the 
existing regulations, which contain mitigation, monitoring, and 
reporting requirements, are consistent with the ``least practicable 
adverse impact standard'' of the MMPA. Pursuant to the MMPA, NMFS is 
requesting comments on its revised negligible impact analyses and 
proposed findings and proposed retention of the existing regulations as 
consistent with the MMPA's least practicable adverse impact standard 
and will consider public comments relevant to this proposed rule prior 
to issuing any final rule. Agency responses will be included in the 
notice of the final decision.

DATES: Comments and information must be received no later than February 
6, 2023.

ADDRESSES: Submit all electronic public comments via the Federal e-
Rulemaking Portal. Go to www.regulations.gov and enter NOAA-NMFS-2022-
0090 in the Search box. Click on the ``Comment'' icon, complete the 
required fields, and enter or attach your comments.
    Instructions: Comments sent by any other method, to any other 
address or individual, or received after the end of the comment period, 
may not be considered by NMFS. All comments received are a part of the 
public record and will generally be posted for public viewing on 
www.regulations.gov without change. All personal identifying 
information (e.g., name, address), confidential business information, 
or otherwise sensitive information submitted voluntarily by the sender 
will be publicly accessible. NMFS will accept anonymous comments (enter 
``N/A'' in the required fields if you wish to remain anonymous). 
Attachments to electronic comments will be accepted in Microsoft Word, 
Excel, or Adobe PDF file formats only.

FOR FURTHER INFORMATION CONTACT: Ben Laws, Office of Protected 
Resources, NMFS, (301) 427-8401.

SUPPLEMENTARY INFORMATION:

Purpose and Need for Regulatory Action

    On January 19, 2021 (86 FR 5322), in response to a petition request 
from the Bureau of Ocean Energy Management (BOEM), NMFS issued a final 
rule under the MMPA, 16 U.S.C. 1361 et seq., for regulations governing 
the take of marine mammals incidental to the conduct of geophysical 
survey activities in the Gulf of Mexico (GOM). This incidental take 
regulation (ITR), which became effective on April 19, 2021, established 
a framework to allow for the issuance of Letters of Authorization 
(LOAs) to authorize take by individual survey operators (50 CFR 
216.106; 86 FR 5322 (January 19, 2021)). Take is expected to occur by 
Level A and/or Level B harassment incidental to use of active sound 
sources as described below.
    Errors discovered in the maximum annual and 5-year take numbers 
during implementation of the ITR preclude NMFS from issuing LOAs for 
the full amount of activity described by BOEM in the petition (as 
revised) and intended to be covered under the ITR. As a result, the 
utility of the rule has been limited. NMFS has produced corrected take 
estimates, including updates to the best available science incorporated 
to the take estimation process (i.e., new marine mammal density 
information), with the result that allowable take numbers are changed 
through this rule. Changes to the take numbers require additional 
analysis to ensure that the necessary statutory findings can still be 
made. This proposed rule revises NMFS' analysis and affirms the 
statutory findings that underlie its January 19, 2021, final rule (86 
FR 5322), based on consideration of information that corrects errors in 
the take estimates that were considered for the final rule. NMFS 
solicits public comment on this proposed rule, including but not 
limited to NMFS' proposed or preliminary findings, determinations or 
conclusions regarding the MMPA standards, and the information NMFS 
relies on in support of those findings, determinations, or conclusions; 
and NMFS' preliminary decisions to reaffirm or not make changes to the 
2021 final rule, and the information NMFS relies on in support of those 
preliminary decisions.

Legal Authority for the Action

    Section 101(a)(5)(A) of the MMPA (16 U.S.C. 1371(a)(5)(A)) directs 
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 for up to 5 years if, 
after notice and public comment, the agency makes certain findings and 
issues regulations that set forth permissible methods of taking 
pursuant to that activity and other means of effecting the ``least 
practicable adverse impact'' on the affected species or stocks and 
their habitat (see the discussion below in the Proposed Mitigation 
section), as well as monitoring and reporting requirements. Under NMFS' 
implementing regulations for section 101(a)(5)(A), NMFS issues LOAs to 
individuals (including entities) seeking authorization for take under 
the activity-specific incidental take regulations (50 CFR 216.106).

Summary of Major Provisions Within the Regulations

    Following is a summary of the major provisions of the current 
regulations regarding geophysical survey activities, which NMFS 
proposes to reaffirm. The regulations contain requirements for 
mitigation, monitoring, and reporting, including:
     Standard detection-based mitigation measures, including 
use of visual and acoustic observation to detect marine mammals and 
shut down acoustic sources in certain circumstances;

[[Page 917]]

     A time-area restriction designed to avoid effects to 
bottlenose dolphins in times and places believed to be of particular 
importance;
     Vessel strike avoidance measures; and
     Monitoring and reporting requirements.
    The ITR would continue to govern and allow for the issuance of LOAs 
for the take of marine mammals incidental to the specified activity 
(which is unchanged from what was described in the 2021 final rule), 
within the upper bounds of take evaluated herein.

Background

    The MMPA prohibits the ``take'' of marine mammals, with certain 
exceptions. Sections 101(a)(5)(A) and (D) of the MMPA (16 U.S.C. 1361 
et seq.) direct the Secretary of Commerce (as delegated to NMFS) 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 incidental take authorization may be provided to the public 
for review.
    Authorization for incidental takings shall be granted if NMFS finds 
that the taking will have a negligible impact on the species or 
stock(s) and will not have an unmitigable adverse impact on the 
availability of the species or stock(s) for taking for subsistence uses 
(where relevant). Further, NMFS must prescribe the permissible methods 
of taking and other ``means of effecting the least practicable adverse 
impact'' on the affected species or stocks and their habitat, paying 
particular attention to rookeries, mating grounds, and areas of similar 
significance, and on the availability of the species or stocks for 
taking for certain subsistence uses (referred to as ``mitigation''); 
and set forth requirements pertaining to the monitoring and reporting 
of the takings. The definitions of all applicable MMPA statutory terms 
cited above are included in the relevant sections below.
    On October 17, 2016, BOEM submitted a revised petition \1\ to NMFS 
for rulemaking under section 101(a)(5)(A) of the MMPA to authorize take 
of marine mammals incidental to conducting geophysical surveys during 
oil and gas industry exploration and development activities in the GOM. 
This revised petition was deemed adequate and complete based on NMFS' 
implementing regulations at 50 CFR 216.104.
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    \1\ In the 2018 notice of proposed rulemaking (83 FR 29212, June 
22, 2018), NMFS provided a brief history of prior petitions received 
from BOEM's predecessor agencies.
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    NMFS published a notice of proposed rulemaking in the Federal 
Register for a 60-day public review on June 22, 2018 (83 FR 29212) 
(``2018 proposed rule''). All comments received are available online at 
www.fisheries.noaa.gov/action/incidental-take-authorization-oil-and-gas-industry-geophysical-survey-activity-gulf-mexico.
    On February 24, 2020, BOEM submitted a notice to NMFS of its 
``updated proposed action and action area for the ongoing [ITR] 
process[.]'' This update consisted of removal of the area then under a 
Congressional leasing moratorium under the Gulf of Mexico Energy 
Security Act (GOMESA) (Sec. 104, Pub. L. 109-432) \2\ from 
consideration in the ITR. BOEM stated in its notice that survey 
activities are not likely to be proposed within the area subject to the 
leasing moratorium during the 5-year period of effectiveness for the 
ITR and, therefore, that the ``number, type, and effects of any such 
proposed [survey] activities are simply too speculative and uncertain 
for BOEM to predict or meaningfully analyze.'' Based on this updated 
scope, BOEM on March 26, 2020, submitted revised projections of 
expected activity levels and corresponding changes to modeled acoustic 
exposure numbers (i.e., take estimates). BOEM's notice and updated 
information are available online at: www.fisheries.noaa.gov/action/incidental-take-authorization-oil-and-gas-industry-geophysical-survey-activity-gulf-mexico. NMFS incorporated this change in scope and issued 
a final rule and ITR on January 19, 2021 (86 FR 5322) (``2021 final 
rule'' or ``2021 ITR''), which became effective on April 19, 2021. 
Consistent with section 101(a)(5)(A), NMFS may issue LOAs under the 
2021 ITR for a period of 5 years.
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    \2\ The Congressional moratorium in GOMESA was in place until 
June 30, 2022. On September 8, 2020, the President withdrew, under 
section 12 of the Outer Continental Shelf Lands Act, the same area 
covered by the prior GOMESA moratorium from disposition by leasing 
for 10 years, beginning on July 1, 2022, and ending on June 30, 
2032.
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    While processing requests for individual LOAs under the ITR using 
the methodology for developing LOA-specific take numbers presented in 
the rule, NMFS discovered that the estimated maximum annual incidental 
take and estimated total 5-year take from all survey activities that 
BOEM projected for its revised scope appeared to be in error, in that 
maximum annual incidental take was likely to be reached much sooner 
than was anticipated for some species based on the level of activity 
described in BOEM's petition (as revised in 2020). NMFS contacted BOEM 
regarding this, and BOEM determined that, when it reduced its scope of 
specified activity in March 2020 by removing the GOMESA moratorium area 
from its proposed action, it underestimated the level of take by 
inadvertently factoring species density estimates into its revised 
exposure estimates twice. Generally, this miscalculation caused BOEM to 
underestimate the total predicted exposures of species from all survey 
activities in its revision to the petition, most pronouncedly for those 
species with the lowest densities (e.g., killer whales).
    BOEM provided NMFS with an explanation of the miscalculation with 
regard to its incidental take estimate and revised take estimates. See 
the Estimated Take section for additional discussion. NMFS then 
determined it would conduct a rulemaking to analyze the revised take 
estimates and, if appropriate, to revise its incidental take rule 
accordingly.
    Since issuance of the 2021 final rule (at time this proposed rule 
was submitted to the Federal Register), NMFS has issued 34 LOAs 
(www.fisheries.noaa.gov/issued-letters-authorization-oil-and-gas-industry-geophysical-survey-activity-gulf-mexico). Of these 34 LOAs, 17 
have included authorization of take for killer whales. An additional 7 
requests for authorization remain pending as a result of limitations on 
NMFS' ability to authorize additional take of killer whales under the 
rule.

National Environmental Policy Act (NEPA)

    In 2017, BOEM produced a final Programmatic Environmental Impact 
Statement (PEIS) to evaluate the direct, indirect, and cumulative 
impacts of geological and geophysical survey activities in the GOM, 
pursuant to requirements of NEPA. These activities include geophysical 
surveys, as are described in the MMPA petition submitted by BOEM to 
NMFS. The PEIS is available online at: www.boem.gov/Gulf-of-Mexico-Geological-and-Geophysical-Activities-Programmatic-EIS/. NOAA, through 
NMFS, participated in preparation of the PEIS as a cooperating agency 
due to its legal jurisdiction and special expertise in conservation and 
management of marine mammals, including its responsibility to authorize 
incidental take of marine mammals under the MMPA.

[[Page 918]]

    In 2020, NMFS prepared a Record of Decision (ROD) for the following 
purposes: (1) to adopt BOEM's Final PEIS to support NMFS' analysis 
associated with issuance of incidental take authorizations pursuant to 
section 101(a)(5)(A) or (D) of the MMPA and the regulations governing 
the taking and importing of marine mammals (50 CFR part 216); and (2) 
in accordance with 40 CFR 1505.2, to announce and explain the basis for 
NMFS' decision to review and potentially issue incidental take 
authorizations under the MMPA on a case-by-case basis, if appropriate.
    The Council on Environmental Quality (CEQ) regulations state that 
``[a]gencies shall prepare supplements to either draft or final 
environmental impact statements if: (i) the agency makes substantial 
changes in the proposed action that are relevant to environmental 
concerns; or (ii) there are significant new circumstances or 
information relevant to environmental concerns and bearing on the 
proposed action or its impacts.'' (40 CFR 1502.09(c)). In addition, 
NMFS has considered CEQ's ``significance'' criteria at 40 CFR 1508.27 
and the criteria relied upon for the 2020 ROD to determine whether any 
new circumstances or information are ``significant,'' thereby requiring 
supplementation of the 2017 PEIS.
    For this proposed action, NMFS has reevaluated its findings related 
to the MMPA negligible impact standard and the least practicable 
adverse impact standard governing its regulations in light of the 
corrected take estimates and other relevant new information. Based on 
that evaluation, NMFS preliminarily reaffirms its negligible impact 
determinations and preliminarily finds that the corrected and 
additional data do not result in the need for revised mitigation and 
monitoring measures under the least practicable adverse impact 
standard.
    NMFS also considered whether there are any significant new 
circumstances or information that are relevant to environmental 
concerns and have a bearing on this proposed action or its impacts. For 
our consideration of new circumstances and information, we consulted 
scientific publications from 2021-22, data that were collected by the 
agency and other entities after the PEIS was completed, field reports, 
and other sources (e.g., updated NMFS Stock Assessment Reports (SAR), 
reports produced under the BOEM-funded Gulf of Mexico Marine Assessment 
Program for Protected Species (GoMMAPPS) project (see www.boem.gov/gommapps)). The new circumstances and information are related to 
updated information on Rice's whales in the action area (population 
abundance, mortality and sources of mortality, distribution and 
occurrence) and any new data, analysis, or information on the effects 
of geophysical survey activity on marine mammals and relating to the 
effectiveness and practicability of measures to reduce the risk 
associated with impacts of such survey activity. Based on this review, 
NMFS has preliminarily determined that supplementation of the 2017 PEIS 
is not warranted.

Summary of the Proposed Action

    This proposed rule provides analysis of the same activities and 
activity levels considered for the 2021 final rule for the same 
original five-year period of time and utilizes the same modeling 
methodology described in the 2021 final rule. We incorporate the best 
available information, including consideration of specific new 
information that has become available since the 2021 rule was published 
and updates to currently available marine mammal density information. 
This proposed rule also incorporates expanded modeling results that 
estimate take utilizing the existing methodology but also consider the 
effects of using smaller (relative to the proxy source originally 
defined by BOEM) airgun arrays currently prevalent, as evidenced by LOA 
applications received by NMFS to date (see www.fisheries.noaa.gov/issued-letters-authorization-oil-and-gas-industry-geophysical-survey-activity-gulf-mexico).
    There are no changes to the nature or level of the specified 
activities within or across years or to the geographic scope of the 
activity. Based on our preliminary assessment of the specified activity 
in light of the revised take estimates and other new information, we 
have determined that the 2021 regulations at 50 CFR 217.180, including 
the required mitigation and associated monitoring measures, satisfy the 
MMPA requirement to prescribe the means of effecting the least 
practicable adverse impact on the affected species or stocks and their 
habitat, and therefore, do not propose to change those regulations, nor 
do we propose to change the requirements pertaining to monitoring and 
reporting. This rulemaking supplements the information supporting the 
2021 incidental take rule. This proposed rule would not change the 
existing expiration date of the 2021 regulations (April 19, 2026). In 
addition, NMFS' demarcation of ``years'' under the 2021 final rule for 
purposes of accounting for authorized take (e.g., Year 1 under the rule 
extended from April 19, 2021, through April 18, 2022) would remain 
unchanged under this proposed rule.
    As to the negligible impact findings, the revised take numbers 
remain within those previously analyzed for most species. (Take numbers 
increased compared with the 2021 final rule for four species: Rice's 
whale, Fraser's dolphin, rough-toothed dolphin, and striped dolphin. 
See Tables 5 and 6. Because of the new category of blackfish, there is 
uncertainty on any change in the take numbers for the individual 
species that comprise that category, though collectively the take 
numbers for all species in the blackfish category remain within the 
levels previously analyzed.) However, we revisited the risk assessment 
framework used in the 2021 analyses for all species, as elements of the 
framework are dependent on information related to stock abundance, 
which has been updated. For most species, we provide updated negligible 
impact analyses and determinations. For those species for which take 
numbers decreased and associated evaluated risk remained static or 
declined, we incorporate (by either repeating, summarizing, or 
referencing) applicable information and analyses in the prior 
rulemaking and supporting documents. For those species, there is no 
other new information suggesting that the effect of the anticipated 
take might exceed what was considered in the 2021 final rule. 
Therefore, the analyses and findings included in the documents provided 
and produced in support of the 2021 final rule remain current and 
applicable. Please see the Negligible Impact Analysis and 
Determinations section for further information. As to the small numbers 
standard, we do not propose to change the interpretation and 
implementation as laid out in the 2021 final rule.

Description of the Specified Activity

Overview

    The specified activity for this proposed action is unchanged from 
the specified activity considered for the 2021 ITR, consisting of 
geophysical surveys conducted for a variety of reasons. BOEM's 2016 
petition described a 10-year period of geophysical survey activity and 
provided estimates of the amount of effort by survey type and location. 
BOEM's 2020 update to the scope of activity included revisions to these 
level-of-effort projections, including limiting the projections to 5 
years and removing activity assumed to occur within the areas removed 
from the

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scope of activity. Actual total amounts of effort (including by survey 
type and location) are not known in advance of receiving LOA requests, 
but take in excess of what is analyzed in this rule would not be 
authorized. Applicants seeking authorization for take of marine mammals 
incidental to survey activities outside the geographic scope of the 
rule (i.e., within the former GOMESA moratorium area) would need to 
pursue a separate MMPA incidental take authorization. See Figures 1 and 
2.
    Geophysical surveys in the GOM are typically conducted in support 
of hydrocarbon exploration, development, and production by companies 
that provide such services to the oil and gas industry. Broadly, these 
surveys include deep penetration surveys using large airgun arrays as 
the acoustic source; shallow penetration surveys using a small airgun 
array, single airgun, or other systems that may achieve similar 
objectives (here considered broadly as including boomers and sparkers) 
as the acoustic source; or high-resolution surveys, which may use a 
variety of acoustic sources. Geophysical surveys and associated 
acoustic sources were described in detail in NMFS' 2018 notice of 
proposed rulemaking and in the notice of issuance for the 2021 final 
rule. Please see those notices for detailed discussion of geophysical 
survey operations, associated acoustic sources, and the specific 
sources and survey types that were the subject of acoustic exposure 
modeling. Information provided therein remains accurate and relevant 
and is not repeated here. The use of these acoustic sources produces 
underwater sound at levels that have the potential to result in 
harassment of marine mammals. Marine mammal species with the potential 
to be present in the GOM are described below (see Table 2).
    Generally speaking, survey activity projected by BOEM may occur 
within Federal territorial waters and waters of the U.S. Exclusive 
Economic Zone (EEZ) (i.e., to 200 nautical miles (nmi)) within the GOM, 
and/or corresponding with BOEM's GOM Outer Continental Shelf planning 
areas (i.e., Western Planning Area (WPA), Central Planning Area (CPA), 
Eastern Planning Area (EPA)).

Dates and Duration

    The dates and duration of the specified activities considered for 
this proposed rule are unchanged from the dates and duration for the 
2021 final rule, which may occur at any time during the period of 
validity of the regulations (April 19, 2021, through April 18, 2026).

Specified Geographical Region

    The specified geographical region for this proposed action is 
unchanged from the one considered for the 2021 final rule. The OCS 
planning areas are depicted in Figure 1, and the overlap of the former 
GOMESA moratorium area, which is now withdrawn from leasing 
consideration, with the geographical region (as well as with the 
modeling zones) is depicted in Figure 2. NMFS provided a detailed 
discussion of the specified geographical region in the 2018 notice of 
proposed rulemaking.
BILLING CODE 3510-22-P
[GRAPHIC] [TIFF OMITTED] TP05JA23.000


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[GRAPHIC] [TIFF OMITTED] TP05JA23.001

BILLING CODE 3510-22-C

Summary of Representative Sound Sources

    The 2021 final rule allows for the authorization of take, through 
LOAs, incidental to airguns of different sizes and configurations. The 
supporting modeling considered two specific airgun array sizes/
configurations (as well as a single airgun). For this proposed rule, 
modeling of a third representative airgun size is also specifically 
considered. Acoustic exposure modeling performed in support of the 2021 
rule was described in detail in ``Acoustic Propagation and Marine 
Mammal Exposure Modeling of Geological and Geophysical Sources in the 
Gulf of Mexico'' and ``Addendum to Acoustic Propagation and Marine 
Mammal Exposure Modeling of Geological and Geophysical Sources in the 
Gulf of Mexico'' (Zeddies et al., 2015, 2017a), as well as in ``Gulf of 
Mexico Acoustic Exposure Model Variable Analysis'' (Zeddies et al., 
2017b), which evaluated a smaller, alternative airgun array. Modeling 
of a smaller, more representative, airgun array considered in this 
proposed rule is described in a 2022 memorandum (Weirathmueller et al., 
2022). These reports provide full detail regarding the modeled acoustic 
sources and survey types and are available online at: 
www.fisheries.noaa.gov/action/incidental-take-authorization-oil-and-gas-industry-geophysical-survey-activity-gulf-mexico.
    Representative sources for the modeling include three different 
airgun arrays, a single airgun, and an acoustic source package 
including a CHIRP sub-bottom profiler in combination with multibeam 
echosounder and side-scan sonar. Two major survey types were 
considered: large-area (including 2D, 3D narrow azimuth (NAZ), 3D wide 
azimuth (WAZ), and coil surveys) and small-area (including single 
airgun surveys and high-resolution surveys; the single airgun was used 
as a conservative proxy for surveys using a boomer or sparker). The 
nominal airgun sources used for analysis of the specified activity 
include a single airgun (90-in\3\ airgun) and a large airgun array 
(8,000 in\3\). In addition, the Model Variable Analysis (Zeddies et 
al., 2017b) provides analysis of an alternative 4,130-in\3\ array, and 
the most recent modeling effort using the same methodology provides 
analysis of a 5,110-in\3\ array (Weirathmueller et al., 2022), with 
specifications defined by NMFS in consultation with industry operators 
to provide exposure modeling results more relevant to arrays commonly 
in use (see Letters of Authorization section). Additional discussion is 
provided in the Estimated Take section.
    While it was necessary to identify representative sources for the 
purposes of modeling take estimates for the analysis for the 2021 rule, 
the analysis is intended to be, and is appropriately, applicable to 
takes resulting from the use of other sizes or configurations of 
airguns (e.g., the smaller, 5,110-in\3\ airgun array currently 
prevalent in GOM survey effort and described in Weirathmueller et al. 
(2022), and the alternative 4,130-in\3\ array initially modeled by 
Zeddies et al. (2017b)). Although the analysis herein is based on the 
worst-case modeling results (for most species, those resulting from use 
of the 8,000-in\3\ array), actual take numbers for authorization 
through LOAs are generated based on the results most applicable to the 
array planned for use.
    While these descriptions reflect existing technologies and current 
practice, new technologies and/or uses of existing technologies may 
come into practice during the remaining period of validity of these 
regulations. As stated in the 2021 final rule, NMFS will evaluate any 
such developments on a case-specific basis to determine whether

[[Page 921]]

expected impacts on marine mammals are consistent with those described 
or referenced in this document and, therefore, whether any anticipated 
take incidental to use of those new technologies or practices may 
appropriately be authorized under the existing regulatory framework. 
See Letters of Authorization for additional information.

Estimated Levels of Effort

    As noted above, estimated levels of effort are unchanged from those 
considered in the 2021 final rule. Please see the 2021 final rule 
notice for additional detailed discussion of those estimates and of the 
approach to delineating modeling zones (shown in Figure 2).
    In support of its 2020 revision of the scope of the rule, BOEM 
provided NMFS with revised 5-year level of effort predictions and 
associated acoustic exposure estimates. Table 1 provides those effort 
projections for the 5-year period, which are unchanged.

                                              Table 1--Projected Levels of Effort in 24-Hr Survey Days for Five Years, by Zone and Survey Type \1\
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                                                                                                                                                    Shallow                              Total
                            Year                               Zone \2\     2D \3\    3D NAZ \3\  3D WAZ \3\   Coil \3\     VSP \3\      Total      hazards   Boomer \4\    HRG \4\    (shallow)
                                                                                                                                      (deep) \3\      \4\                                 \4\
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1...........................................................           1           0           0           0           0           0           0           0           0           0           0
                                                                       2           0         236           0           0           0         236           2           0          18          20
                                                                       3           0          30           0           0           0          30           0           0           4           4
                                                                       4           0           0           0           0           0           0           0           0           0           0
                                                                       5          54         373         184          79           2         692           0           0          25          25
                                                                       6           0         186          49          21           0         256           0           0          10          10
                                                                       7          46         346         166          71           1         630           0           0          23          23
                                                             -----------------------------------------------------------------------------------------------------------------------------------
    Total...................................................  ..........         100       1,171         399         171           3       1,844           2           0          80          82
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2...........................................................           1           0           0           0           0           0           0           0           0           0           0
                                                                       2           0         354          42          19           0         415           2           0          18          20
                                                                       3           0           0           0           0           0           0           0           0           4           4
                                                                       4           6           0           0           0           0           6           0           0           0           0
                                                                       5           0         373         184          79           2         638           0           0          25          25
                                                                       6           0          99           0           0           0          99           0           0          11          11
                                                                       7          20         336         162          69           1         588           0           0          23          23
                                                             -----------------------------------------------------------------------------------------------------------------------------------
    Total...................................................  ..........          26       1,162         388         167           3       1,746           2           0          81          83
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3...........................................................           1           0           0           0           0           0           0           0           0           0           0
                                                                       2           0         236           0           0           0         236           2           0          18          20
                                                                       3           0           0           0           0           0           0           0           0           4           4
                                                                       4           0           0           0           0           0           0           0           0           0           0
                                                                       5           0         328         154          66           2         550           0           0          26          26
                                                                       6           0         186          49          21           0         256           0           0          12          12
                                                                       7           0         306         139          60           1         506           0           0          24          24
                                                             -----------------------------------------------------------------------------------------------------------------------------------
    Total...................................................  ..........           0       1,056         342         147           3       1,548           2           0          84          86
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4...........................................................           1           0           0           0           0           0           0           0           0           0           0
                                                                       2           0         354          42          19           0         415           2           1          16          19
                                                                       3           0          30           0           0           0          30           0           0           3           3
                                                                       4          12          11           0           0           0          23           0           0           0           0
                                                                       5          27         237          92          40           2         398           0           0          26          26
                                                                       6           0          99           0           0           0          99           0           0          12          12
                                                                       7          63         255          94          40           1         453           0           0          24          24
                                                             -----------------------------------------------------------------------------------------------------------------------------------
    Total...................................................  ..........         102         986         228          99           3       1,418           2           1          81          84
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
5...........................................................           1           0           0           0           0           0           0           0           0           0           0
                                                                       2           0         236           0           0           0         236           0           0          19          19
                                                                       3           0           0           0           0           0           0           0           0           3           3
                                                                       4           0          17           0           0           0          17           0           0           0           0
                                                                       5           0         283         184          79           2         548           2           1          24          27
                                                                       6           0          99           0           0           0          99           0           0          13          13
                                                                       7           0         313         162          69           2         546           2           1          23          26
                                                             -----------------------------------------------------------------------------------------------------------------------------------
    Total...................................................  ..........           0         948         346         148           4       1,446           4           2          82          88
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ Projected levels of effort in 24-hr survey days. This table corrects Table 2 in NMFS' notice of issuance of the 2021 ITR, which erroneously presented the difference in activity levels
  between the 2018 proposed ITR and the revised levels after GOMESA removal. The correct information was concurrently made available to the public via BOEM's 2020 notice to NMFS of its updated
  scope.
\2\ Zones follow the zones depicted in Figure 2.
\3\ Deep penetration survey types include 2D, which uses one source vessel with one source array; 3D NAZ, which uses two source vessels using one source array each; 3D WAZ and coil, each of
  which uses four source vessels using one source array each (but with differing survey design); and VSP, which uses one source vessel with one source array. ``Deep'' refers to survey type,
  not to water depth. Assumptions related to modeled source and survey types were made by BOEM in its petition for rulemaking.
\4\ Shallow penetration/HRG survey types include shallow hazards surveys, assumed to use a single 90-in\3\ airgun or boomer, and high-resolution surveys using the multibeam echosounder, side-
  scan sonar, and CHIRP sub-bottom profiler systems concurrently. ``Shallow'' refers to survey type, not to water depth.

    The preceding description of the specified activity is a summary of 
critical information. The interested reader should refer to the 2018 
notice of proposed rulemaking (83 FR 29212, June 22, 2018), as well as 
BOEM's petition (with recent addenda) and PEIS, for additional detail 
regarding these activities and the region. Required mitigation, 
monitoring, and reporting measures are described later in this document 
(see Proposed Mitigation and Proposed Monitoring and Reporting).

[[Page 922]]

Description of Marine Mammals in the Area of the Specified Activities

    Table 2 lists all species with expected potential for occurrence in 
the GOM and summarizes information related to the population or stock, 
including potential biological removal (PBR). PBR, defined by the MMPA 
as the maximum number of animals, not including natural mortalities, 
that may be removed from a marine mammal stock while allowing that 
stock to reach or maintain its optimum sustainable population, is 
considered in concert with known sources of ongoing anthropogenic 
mortality (as described in NMFS' SARs). For status of species, we 
provide information regarding U.S. regulatory status under the MMPA and 
Endangered Species Act (ESA). The affected species and stocks have not 
changed from those described in the notice of issuance of the 2021 
rule. We incorporate information newly available since that rule, 
including updated information from NMFS' SARs, but do not otherwise 
repeat discussion provided in either the 2018 notice of proposed 
rulemaking or 2021 notice of issuance of the final rule.
    In some cases, species are treated as guilds (as was the case for 
the analysis conducted in support of the 2021 ITR). In general 
ecological terms, a guild is a group of species that have similar 
requirements and play a similar role within a community. However, for 
purposes of stock assessment or abundance prediction, certain species 
may be treated together as a guild because they are difficult to 
distinguish visually and many observations are ambiguous. For example, 
NMFS' GOM SARs assess stocks of Mesoplodon spp. and Kogia spp. as 
guilds. As was the case for the 2021 rule, we consider beaked whales 
and Kogia spp. as guilds. In this proposed rule, reference to ``beaked 
whales'' includes the Cuvier's, Blainville's, and Gervais beaked 
whales, and reference to ``Kogia spp.'' includes both the dwarf and 
pygmy sperm whale.
    The use of guilds in the 2021 final rule followed the best 
available density information at the time (i.e., Roberts et al., 2016). 
Subsequently, updated density information became available for all 
species except for Fraser's dolphin and rough-toothed dolphin (Garrison 
et al., 2022). The updated density models retain the treatment of 
beaked whales and Kogia spp. as guilds and have additionally 
consolidated four species into an undifferentiated ``blackfish'' guild. 
These species include the melon-headed whale, false killer whale, pygmy 
killer whale, and killer whale. The model authors determined that, for 
this group of species, there were insufficient sightings of any 
individual species to generate a species-specific model. Therefore, 
reference to ``blackfish'' hereafter includes the melon-headed whale, 
false killer whale, pygmy killer whale, and killer whale.\3\ NMFS 
requests comment regarding whether there is additional data that it 
should consider in this rulemaking related to the aforementioned 
species, in light of NMFS' preliminary determination that Garrison et 
al. (2022) reflects the best available scientific information.
---------------------------------------------------------------------------

    \3\ NMFS' 2021 final rule provided take estimates separately for 
the melon-headed whale, false killer whale, pygmy killer whale, and 
killer whale. This proposed rule provides a single take estimate for 
those four species grouped together as the ``blackfish.'' This 
change in approach reflects the best available scientific 
information, i.e., updated density information (Garrison et al., 
2022). These species are encountered only occasionally during any 
given vessel survey, and these relatively infrequent encounters make 
it difficult to fit species-specific detection and habitat models. 
Roberts et al. (2016) fit species-specific models based on survey 
data from 1992-2009, including 29, 19, 27, and 16 sightings, 
respectively, of these species. For each of these models, the 
authors detail analyses and decisions relevant to model development, 
as well as notes of caution regarding use of the models given the 
associated uncertainty resulting from development of a model based 
on few sightings. The Garrison et al. (2022) models are based on 
survey data from 2003-2018. Notably, surveys conducted after 2009 
were conducted in ``passing'' mode, where the ship did not deviate 
from the trackline to approach and verify species identifications 
for detected marine mammal groups, resulting in an increase in 
observed marine mammal groups that could not be identified to 
species. As a result of these factors, the model authors determined 
it appropriate to develop a single spatial model based on sightings 
of unidentified blackfish, in addition to the relatively few 
sightings where species identification could be confirmed.
---------------------------------------------------------------------------

    Twenty-one species (with 24 managed stocks) have the potential to 
co-occur with the prospective survey activities. For detailed 
discussion of these species, please see the 2018 notice of proposed 
rulemaking. In addition, the West Indian manatee (Trichechus manatus 
latirostris) may be found in coastal waters of the GOM. However, 
manatees are managed by the U.S. Fish and Wildlife Service and are not 
considered further in this document. All managed stocks in this region 
are assessed in NMFS' U.S. Atlantic SARs.
    All values presented in Table 2 are the most recent available at 
the time the analyses for this notice were completed, including 
information presented in NMFS' 2021 SARs (the most recent SARs 
available at the time of publication) (Hayes et al., 2022).

                                    Table 2--Marine Mammals Potentially Present in the Specified Geographical Region
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                                   NMFS stock
                                                                                 ESA/MMPA        abundance (CV,    Predicted mean (CV)/           Annual
           Common name                Scientific name           Stock             status;      Nmin, most recent    maximum abundance     PBR      M/SI
                                                                               strategic (Y/   abundance survey)           \3\                     \4\
                                                                                  N) \1\              \2\
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                          Order Cetartiodactyla--Cetacea--Superfamily Mysticeti (baleen whales)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Family Balaenopteridae
 (rorquals):
    Rice's whale \5\.............  Balaenoptera ricei..  Gulf of Mexico.....  E/D; Y          51 (0.50; 34; 2017-  37 (0.52)..........      0.1      0.5
                                                                                               18).
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                            Superfamily Odontoceti (toothed whales, dolphins, and porpoises)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Family Physeteridae:
    Sperm whale..................  Physeter              GOM................  E/D; Y          1,180 (0.22; 983;    3,007 (0.15).......      2.0      9.6
                                    macrocephalus.                                             2017-18).
Family Kogiidae:
    Pygmy sperm whale............  Kogia breviceps.....  GOM................  -; N            336 (0.35; 253;      980 (0.16).........      2.5       31
                                                                                               2017-18) \6\ \7\.
    Dwarf sperm whale............  K. sima.............  GOM................  -; N
Family Ziphiidae (beaked whales):
    Cuvier's beaked whale........  Ziphius cavirostris.  GOM................  -; N            See Footnotes 7-8..  803 (0.18).........      0.1      5.2
    Gervais beaked whale.........  Mesoplodon europaeus  GOM................  -; N

[[Page 923]]

 
    Blainville's beaked whale....  M. densirostris.....  GOM................  -; N                                                          0.7
Family Delphinidae:
    Rough-toothed dolphin........  Steno bredanensis...  GOM................  -; N            3,509 (0.67; Unk.;   4,853 (0.19).......   Undet.       39
                                                                                               2009).
    Common bottlenose dolphin \7\  Tursiops truncatus    GOM Oceanic........  -; N            7,462 (0.31; 5,769;  155,453 (0.13)            58       32
                                    truncatus.                                                 2017-18).            (Shelf) 9,672
                                                                                                                    (0.15) (Oceanic).
                                                         GOM Continental      -; N            63,280 (0.11;                                 556       65
                                                          Shelf.                               57,917; 2017-18).
                                                         GOM Coastal,         -; N            11,543 (0.19;                                  89       28
                                                          Northern.                            9,881; 2017-18).
                                                         GOM Coastal,         -; N            20,759 (0.13;                                 167       36
                                                          Western.                             18,585; 2017-18).
    Clymene dolphin..............  Stenella clymene....  GOM................  -; N            513 (1.03; 250;      4,619 (0.35).......      2.5      8.4
                                                                                               2017-18).
    Atlantic spotted dolphin.....  S. frontalis........  GOM................  -; N            21,506 (0.26;        6,187 (0.33)             166       36
                                                                                               17,339; 2017-18).    (Shelf) 1,782
                                                                                                                    (0.19) (Oceanic).
    Pantropical spotted dolphin..  S. attenuata          GOM................  -; N            37,195 (0.24;        67,225 (0.27)......      304      241
                                    attenuata.                                                 30,377; 2017-18).
    Spinner dolphin..............  S. longirostris       GOM................  -; N            2,991 (0.54; 1,954;  5,548 (0.40).......       20      113
                                    longirostris.                                              2017-18).
    Striped dolphin..............  S. coeruleoalba.....  GOM................  -; N            1,817 (0.56; 1,172;  5,634 (0.18).......       12       13
                                                                                               2017-18).
    Fraser's dolphin.............  Lagenodelphis hosei.  GOM................  -; N            213 (1.03; 104;      1,665 (0.73).......        1     Unk.
                                                                                               2017-18).
    Risso's dolphin..............  Grampus griseus.....  GOM................  -; N            1,974 (0.46; 1,368;  1,501 (0.27).......       14      5.3
                                                                                               2017-18).
    Melon-headed whale...........  Peponocephala         GOM................  -; N            1,749 (0.68; 1,039;  6,113 (0.20).......       10      9.5
                                    electra.                                                   2017-18).
    Pygmy killer whale...........  Feresa attenuata....  GOM................  -; N            613 (1.15; 283;                               2.8      1.6
                                                                                               2017-18).
    False killer whale...........  Pseudorca crassidens  GOM................  -; N            494 (0.79; 276;                               2.8      2.2
                                                                                               2017-18).
    Killer whale.................  Orcinus orca........  GOM................  -; N            267 (0.75; 152;                               1.5     Unk.
                                                                                               2017-18).
    Short-finned pilot whale.....  Globicephala          GOM................  -; N            1,321 (0.43; 934;    2,741 (0.18).......      7.5      3.9
                                    macrorhynchus.                                             2017-18).
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ ESA status: Endangered (E)/MMPA status: Depleted (D). A dash (-) indicates that the species is not listed under the ESA or designated as depleted
  under the MMPA. Under the MMPA, a strategic stock is one for which the level of direct human-caused mortality exceeds PBR or which is determined to be
  declining and likely to be listed under the ESA within the foreseeable future. Any species or stock listed under the ESA is automatically designated
  under the MMPA as depleted and as a strategic stock.
\2\ NMFS marine mammal stock assessment reports online at: www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessments. CV
  is coefficient of variation; Nmin is the minimum estimate of stock abundance.
\3\ This information represents species- or guild-specific abundance predicted by habitat-based cetacean density models (Roberts et al., 2016; Garrison
  et al., 2022). These models provide the best available scientific information regarding predicted density patterns of cetaceans in the U.S. Gulf of
  Mexico, and we provide the corresponding abundance predictions as a point of reference. Total abundance estimates were produced by computing the mean
  density of all pixels in the modeled area and multiplying by its area. Abundance predictions for Fraser's dolphin and rough-toothed dolphin from
  Roberts et al. (2016); abundance predictions for other taxa represent the maximum predicted abundance from Garrison et al. (2022).
\4\ These values, found in NMFS' SARs, represent annual levels of human-caused mortality plus serious injury from all sources combined (e.g., commercial
  fisheries, ship strike). These values are generally considered minimums because, among other reasons, not all fisheries that could interact with a
  particular stock are observed and/or observer coverage is very low, and, for some stocks (such as the Atlantic spotted dolphin and continental shelf
  stock of bottlenose dolphin), no estimate for injury due to the Deepwater Horizon oil spill has been included. See SARs for further discussion.
\5\ The 2021 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).
\6\ NMFS' 2020 SARs state that the abundance estimate provided for Kogia spp. is likely a severe underestimate because it was not corrected for the
  probability of detection on the trackline, and because Kogia spp. are often difficult to see, present little of themselves at the surface, do not
  fluke when they dive, and have long dive times. In addition, they exhibit avoidance behavior towards ships and changes in behavior towards approaching
  survey aircraft. See Hayes et al. (2021).
\7\ Abundance estimates are in some cases reported for a guild or group of species when those species are difficult to differentiate at sea. Similarly,
  habitat-based cetacean density models are based in part on available observational data which, in some cases, is limited to genus or guild in terms of
  taxonomic definition. NMFS' SARs present pooled abundance estimates for Kogia spp. and Mesoplodon spp., while Garrison et al. (2022) produced density
  models to genus level for Kogia spp. and as a guild for beaked whales (Ziphius cavirostris and Mesoplodon spp.) and ``blackfish'' (pygmy killer whale,
  false killer whale, melon-headed whale, and killer whale). Finally, Garrison et al. (2022) produced density models for bottlenose dolphins that do not
  differentiate between stocks, but between oceanic and shelf dolphins.
\8\ NMFS' 2020 SARs provide various abundance estimates for beaked whales: Cuvier's beaked whale, 18 (CV = 0.75); Gervais' beaked whale, 20 (CV=0.98);
  unidentified Mesoplodont species, 98 (CV = 0.46); and unidentified Ziphiids, 181 (CV = 0.31). The SARs state that these estimates likely represent
  severe underestimates, as they were not corrected for the probability of detection on the trackline, and due to the long dive times of these species.
  See Hayes et al. (2021).

    In Table 2 above, we report two sets of abundance estimates: those 
from NMFS' SARs and those predicted by habitat-based cetacean density 
models. Please see footnote 3 of Table 2 for more detail. NMFS' SAR 
estimates are typically generated from the most recent shipboard and/or 
aerial surveys conducted. GOM oceanography is dynamic, and the spatial 
scale of the GOM is small relative to the ability of most cetacean 
species to travel. U.S. waters only comprise about 40 percent of the 
entire GOM, and 65 percent of GOM oceanic waters are south of the U.S. 
EEZ. Studies based on abundance and distribution surveys restricted to 
U.S. waters are unable to detect temporal shifts in distribution beyond 
U.S. waters that might account for any changes in abundance within U.S. 
waters. NMFS' SAR estimates also in some cases do not incorporate 
correction for detection bias. Therefore,

[[Page 924]]

for cryptic or long-diving species (e.g., beaked whales, Kogia spp., 
sperm whales), they should generally be considered underestimates (see 
footnotes 6 and 8 of Table 2).
    The model-based abundance estimates represent the output of 
predictive models derived from multi-year observations and associated 
environmental parameters and which incorporate corrections for 
detection bias (the same models and data from which the density 
estimates are derived). Incorporating more data over multiple years of 
observation can yield different results in either direction, as the 
result is not as readily influenced by fine-scale shifts in species 
habitat preferences or by the absence of a species in the study area 
during a given year. NMFS' SAR abundance estimates show substantial 
year-to-year variability in some cases. Incorporation of correction for 
detection bias should systematically result in greater abundance 
predictions. For these reasons, the model-based estimates are generally 
more realistic and, for these purposes, represent the best available 
information. Specifically, for assessing estimated exposures relative 
to abundance--used in this case to understand the scale of the 
predicted takes compared to the population--NMFS generally believes 
that the model-based abundance predictions are most appropriate because 
they were used to generate the exposure estimates and therefore, 
provide the most relevant comparison.
    As discussed in footnote 3 of Table 2, NMFS' 2021 final rule 
provided take estimates separately for the melon-headed whale, false 
killer whale, pygmy killer whale, and killer whale. This proposed rule 
provides a single take estimate for those four species grouped together 
as the ``blackfish.'' This approach was dictated by the best available 
science. The model authors determined it necessary to aggregate the few 
sightings data available for each of the four species with sightings 
data that could not be resolved to the species level in order to 
develop a density model, as there were not sufficient confirmed 
sightings of individual species to create individual spatial models. 
Further, the model authors advised that any attempt to parse the 
results to species would be fraught with complicated assumptions and 
limited data, and that there is no readily available way to do so in a 
scientifically defensible manner. Previous estimates (Roberts et al., 
2016) were based on older data (data range 1992-2009 versus 2003-2018), 
and the updated models notably include post-Deepwater Horizon (DWH) oil 
spill survey data and, for the first time, winter survey data. 
Nonetheless, interested members of the public may review the 2018 
proposed rule and supporting documentation, which assumed slightly 
greater activity levels and larger take numbers, and still found a 
negligible impact on all four blackfish species.
    NMFS does not have sufficient information to support apportioning 
those blackfish takes to species, but we note that the sum of annual 
average evaluated take for the four species in the 2021 final rule is 
64,742, while the new annual average take estimate for blackfish (using 
the updated density information) is 55,441. While some may speculate 
that estimated take of killer whales (as part of the blackfish group) 
has increased relative to that evaluated in the 2021 final rule (annual 
average take of 52), NMFS has no specific information to support such 
an assumption.
    NMFS' ability to issue LOAs under the 2021 rule to date has been 
limited specifically with regard to killer whales, because BOEM's error 
most severely affected killer whale take numbers. (Evaluated Rice's 
whale takes were similarly affected, but were generally not implicated 
in LOA requests based on the location of planned surveys.) Effects to 
killer whales from the specified activity have not presented serious 
concern in a negligible impact context, even considering the original 
take numbers evaluated in NMFS' 2018 proposed rule (annual average take 
of 1,160) which produced overall scenario-specific risk ratings of low 
to moderate. Evaluated risk is similar across the 2018 proposed rule 
and this proposed rule.
    Further, we note that we make a conservative assumption in this 
rule in the application of the risk assessment framework to blackfish. 
Risk is a product of severity and vulnerability. While severity is 
based on density and abundance and is, therefore, reflective of the new 
density information, vulnerability is based on species-specific factors 
and is different for the four species. We applied the highest 
vulnerability score of the four to combine with the severity to get the 
overall risk rating for the group. Please see Negligible Impact 
Analysis and Determinations for additional discussion.
    As part of our evaluation of the environmental baseline, which is 
considered as part of the negligible impact analysis, we consider any 
known areas of importance as marine mammal habitat (e.g., recognized 
Biologically Important Areas (BIA)). We also consider other relevant 
events, such as unusual mortality events (UME) and the 2010 DWH oil 
spill. The 2018 notice of proposed rulemaking provided detailed 
discussion of important marine mammal habitat, relevant UMEs, and of 
the DWH oil spill. The 2021 notice of issuance of the final rule 
updated those discussions as necessary. That information is 
incorporated by reference here and updated where necessary. There have 
been no new UMEs, or new information regarding the UMEs discussed in 
the prior notices. Similarly, there is no new information regarding the 
DWH oil spill that impacts our consideration of that event as part of 
the environmental baseline. We do note that estimates of annual 
mortality for many stocks over the period 2014-2018 now include 
mortality attributed to the effects of the DWH oil spill (see Table 2).
    Areas of important marine mammal habitat may include designated 
critical habitat for ESA-listed species (as defined by section 3 of the 
ESA) or other known areas not formally designated pursuant to any 
statute or other law. Important areas may include areas of known 
importance for reproduction, feeding, or migration, or areas where 
small and resident populations are known to occur.
    As noted above in Table 2, the former GOM Bryde's whale has been 
described as a new species, Rice's whale (Rosel et al., 2021). No 
critical habitat has yet been designated for the species. However, a 
Rice's whale BIA is recognized (LaBrecque et al., 2015). This year-
round BIA was discussed in the aforementioned notices, and we do not 
repeat the description of the 2015 BIA.
    NOAA conducted a status review of the former GOM Bryde's whale 
(Rosel et al., 2016). The review expanded the BIA description by 
stating that, due to the depth of some sightings, the area is more 
appropriately defined to the 400-m isobath and westward to Mobile Bay, 
Alabama, in order to provide some buffer around the deeper sightings 
and to include all sightings in the northeastern GOM. Following the 
description provided by Rosel et al. (2016), the 2018 proposed 
rulemaking considered a Rice's whale ``core habitat area'' that was 
designated as between the 100- and 400-m isobaths, from 87.5[deg] W to 
27.5[deg] N (83 FR 29212, August 21, 2018), in order to appropriately 
encompass Rice's whale sightings at the time. In addition, the area 
largely covered the home range (i.e., 95 percent of predicted 
abundance) predicted by Roberts et al. (2016).
    NMFS subsequently developed an updated description of a ``core 
distribution area''

[[Page 925]]

(www.fisheries.noaa.gov/resource/map/rices-whale-core-distribution-area-map-gis-data), which we refer to herein (Figure 3) while retaining 
the previous terminology for continuity with the 2021 rule (``core 
habitat area''). The updated description is based on visual sightings 
and tag data, and does not imply knowledge of habitat preferences. The 
map was created by first drawing a convex hull polygon around all 
recorded Rice's whale sighting locations (including those recorded as 
Bryde's whale, Bryde's/sei, and Bryde's/sei/fin) from NMFS surveys in 
the northeast GOM, telemetry tag locations from a single whale tagged 
in 2010 (Soldevilla et al., 2017), and acousonde tag locations for one 
whale tagged in 2015 (Soldevilla et al., 2017), comprising a total of 
212 data points collected between 1989 and 2018. It should be noted 
that, other than the positions obtained from the two individually 
tagged whales, it is unknown how many individual whales these sightings 
represent as individuals may have been sighted more than once during a 
cruise or across years. The polygon was trimmed on the western side to 
the 410 m isobath, based on the deepest known sighting (408 m).
    In context of the sparse data from which to accurately define the 
distribution and because many of the sightings fall on the boundary of 
the convex hull polygon, a buffer was added to avoid underestimating 
the potential range of the species. A 10-km buffer was applied to the 
polygon to capture the uncertainty in position and the strip width of 
the visual surveys. This buffer ensures that no sightings are on a 
boundary of the area. An additional 20-km buffer was added to account 
for the possible movement whales could make in any one direction from 
an observed sighting. This buffer was identified by examining the daily 
movement data from a whale tagged for 33 days in 2010 with a satellite-
linked telemetry tag. Two alternative methods were used to identify the 
best indicator of possible daily distance traveled by a whale. First, a 
``daily range'' of movement was estimated by calculating swim speeds 
(km/hr) based upon the distances (and times) between successive 
satellite-tag returns and multiplying that by 24 hr. These daily ranges 
were highly skewed, with most in the 10-30 km range when the whale 
remained in a relatively small area and a few large ranges when the 
whale was traveling northeast to southeast through the habitat. The 
mean of this daily range was 46 km and the median was 21 km. To reduce 
the influence of differences in the number of satellite positions 
returned on any given day, the total distance moved within each 24-hr 
period was summed using all satellite positions in that day. The median 
of this daily range was 17 km and the mean was 30 km. As the median is 
a better measure of central tendency than the mean of highly skewed 
distributions such as those seen here, 20 km was chosen as the most 
likely distance a given observed whale could move within a day of the 
detection. In combination with the 10-km buffer to account for 
uncertainty in whale location during the sighting, this results in the 
placement of a total of a 30-km buffer around the convex hull polygon 
based on sighting locations, producing the area depicted in Figure 3 
(see Proposed Mitigation).

Potential Effects of the Specified Activities on Marine Mammals and 
Their Habitat

    In NMFS' 2018 notice of proposed rulemaking (83 FR 29212, June 22, 
2018), this section included a comprehensive summary and discussion of 
the ways that components of the specified activity may impact marine 
mammals and their habitat, including general background information on 
sound and specific discussion of potential effects to marine mammals 
from noise produced through use of airgun arrays. NMFS provided a 
description of the ways marine mammals may be affected by the same 
activities considered herein, including sensory impairment (permanent 
and temporary threshold shifts and acoustic masking), physiological 
responses (particularly stress responses), behavioral disturbance, or 
habitat effects, as well as of the potential for serious injury or 
mortality. The notice of issuance for the final rule (86 FR 5322, 
January 19, 2021) provided updates to the discussion of potential 
impacts, as well as significantly expanded discussion of certain issues 
(e.g., potential effects to habitat, including prey, and the potential 
for stranding events to occur) in the ``Comments and Responses'' 
section of that notice. These prior notices also provided discussion of 
marine mammal hearing and detailed background discussion of active 
acoustic sources and related acoustic terminology used herein. We have 
reviewed new information available since the 2021 rule was issued. 
Having considered this information, we have determined that there is no 
new information that substantively affects our analysis of potential 
impacts on marine mammals and their habitat that appeared in the 2018 
proposed and 2021 final rules, all of which remains applicable and 
valid for our assessment of the effects of the specified activities 
during the original 5-year period that is the subject of this rule. We 
incorporate by reference that information and do not repeat the 
information here, instead referring the reader to the 2018 notice of 
proposed rulemaking and 2021 notice of issuance of the final rule.
    The Estimated Take section later in this document includes a 
quantitative analysis of the number of individuals that are expected to 
be taken by the specified activity. The Negligible Impact Analysis and 
Determinations section includes an analysis of how these activities 
will impact marine mammals and considers the content of this section, 
the Estimated Take section, and the Proposed Mitigation section, to 
draw conclusions regarding the likely impacts of these activities on 
the reproductive success or survivorship of individuals and from that 
on the affected marine mammal populations.

Estimated Take

    This section provides an estimate of the numbers and type of 
incidental takes that may be expected to occur under the specified 
activity, which informs NMFS' preliminary negligible impact 
determinations. Realized incidental takes would be determined by the 
actual levels of activity at specific times and places that occur under 
any issued LOAs and by the actual acoustic source used. While the 
methodology and modeling for estimating take remains identical to that 
originally described in the 2018 proposed and 2021 final rules, updated 
species density values have been used, and take estimates are available 
for three different airgun array configurations. The highest modeled 
value for each species is analyzed for the negligible impact analysis.
    Except with respect to certain activities not pertinent here, 
section 3(18) of 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). As with the 2021 final 
rule, harassment is the only type of take expected to result from these 
activities. It is unlikely that lethal takes would occur even in the 
absence of the mitigation and monitoring measures, and no such takes 
are anticipated or will be authorized.

[[Page 926]]

    Anticipated takes would primarily be by Level B harassment, as use 
of the described acoustic sources, particularly airgun arrays, is 
likely to disrupt behavioral patterns of marine mammals upon exposure 
to sound at certain levels. There is also some potential for auditory 
injury (Level A harassment) to result for low- and high-frequency 
species due to the size of the predicted auditory injury zones for 
those species, though none is predicted to occur for Rice's whales (the 
only low-frequency cetacean in the GOM). NMFS does not expect auditory 
injury to occur for mid-frequency species. See discussion provided in 
the 2018 notice of proposed rulemaking (83 FR 29212, June 22, 2018) and 
in responses to public comments provided in the notice of issuance for 
the 2021 final rule (86 FR 5322, January 19, 2021).
    Below, we summarize how the take that may be authorized was 
estimated using acoustic thresholds, sound field modeling, and marine 
mammal density data. Detailed discussion of all facets of the take 
estimation process was provided in the 2018 notice of proposed 
rulemaking (83 FR 29212, June 22, 2018), which is incorporated by 
reference here, as it was into the 2021 final rule, as most aspects of 
the modeling have not changed; any aspects of the modeling that have 
changed are noted below and in Weirathmueller et al. (2022). Please see 
that notice, and associated companion documents available online, for 
additional detail. A summary overview of the take estimation process, 
as well as full discussion of new information related to the 
development of estimated take numbers, is provided below.

Acoustic Thresholds

    NMFS uses acoustic thresholds that identify the received level of 
underwater sound above which exposed marine mammals generally would be 
reasonably expected to exhibit disruption of behavioral patterns (Level 
B harassment) or to incur permanent threshold shift (PTS) of some 
degree (Level A harassment). Acoustic criteria used herein were 
described in detail in the preceding notices associated with this ITR; 
that discussion is not repeated as no changes have been made to the 
relevant acoustic criteria. See Tables 3 and 4.

                                      Table 3--Behavioral Exposure Criteria
----------------------------------------------------------------------------------------------------------------
                                                       Probability of response to frequency-weighted rms SPL
                      Group                      ---------------------------------------------------------------
                                                      120 (%)         140 (%)         160 (%)         180 (%)
----------------------------------------------------------------------------------------------------------------
Beaked whales...................................              50              90             n/a             n/a
All other species...............................             n/a              10              50              90
----------------------------------------------------------------------------------------------------------------


                                 Table 4--Exposure Criteria for Auditory Injury
----------------------------------------------------------------------------------------------------------------
                                                                                     Cumulative sound exposure
                                                                                             level \2\
                          Hearing group                           Peak  pressure -------------------------------
                                                                     \1\  (dB)       Impulsive     Non-impulsive
                                                                                       (dB)            (dB)
----------------------------------------------------------------------------------------------------------------
Low-frequency cetaceans.........................................             219             183             199
Mid-frequency cetaceans.........................................             230             185             198
High-frequency cetaceans........................................             202             155            173
----------------------------------------------------------------------------------------------------------------
\1\ Referenced to 1 [mu]Pa; unweighted within generalized hearing range.
\2\ Referenced to 1 [mu]Pa\2\-s; weighted according to appropriate auditory weighting function. Airguns and the
  boomer are treated as impulsive sources; other HRG sources are treated as non-impulsive.

Acoustic Exposure Modeling

    Zeddies et al. (2015, 2017a) provided estimates of the annual 
marine mammal acoustic exposure caused by sounds from geophysical 
survey activity in the GOM for 10 years of notional activity levels, as 
well as full detail regarding the original acoustic exposure modeling 
conducted in support of BOEM's 2016 petition and NMFS' subsequent 
analysis in support of the 2021 final ITR. Zeddies et al. (2017b) 
provided information regarding source and propagation modeling related 
to the 4,130-in\3\ airgun array, and Weirathmueller et al. (2022) 
provide detail regarding the new modeling performed for the 5,110-in\3\ 
airgun array. Detailed discussion of the original modeling effort was 
provided in the notice of proposed rulemaking (83 FR 29212, June 22, 
2018), and through responses to public comments provided in the notice 
of issuance for the final rule (86 FR 5322, January 19, 2021). For full 
details of the modeling effort, the interested reader should see the 
reports (available online at: www.fisheries.noaa.gov/action/incidental-take-authorization-oil-and-gas-industry-geophysical-survey-activity-gulf-mexico) and review discussion provided in prior Federal Register 
notices.
    All acoustic exposure modeling, including source and propagation 
modeling, was redone in support of the action described herein for the 
reasons described below. However, all aspects of the modeling 
(including source, propagation, and animal movement modeling) are the 
same as described in Zeddies et al. (2015, 2017a, 2017b) and discussed 
in previous Federal Register notices associated with the ITR. We do not 
repeat discussion of those aspects of the modeling, but refer the 
reader to those documents.
    Differences from the modeling and modeling products described in 
previous notices associated with this ITR are limited to source and 
propagation modeling of the new 5,110-in\3\ array configuration, which 
was performed using the same procedures as were used for the previous 
8,000- and 4,130-in \3\ array configurations, and two new data inputs: 
(1) updated marine mammal density information (Garrison et al., 2022) 
and (2) revised species definition files. The latter information 
consists of behavioral parameters (e.g., depth, travel rate, dive 
profile) for each species that govern simulated animal (animat) 
movement within the movement model (Weirathmueller et al.,

[[Page 927]]

2022). These files are reviewed at the start of all new and reopened 
modeling efforts, and are updated as necessary according to the most 
recent literature. NMFS previously evaluated full acoustic exposure 
modeling results only for the 8,000-in \3\ airgun array (only 
demonstration results for six species were provided in Zeddies et al. 
(2017b) for the 4,130-in \3\ array configuration), but is now able to 
evaluate full results for all three array configurations; thereby, 
providing for greater flexibility and utility in representing actual 
acoustic sources planned for use during consideration of LOA requests.
    Marine Mammal Density Information--Since the 2021 final rule went 
into effect, new habitat-based cetacean density models have been 
produced by NMFS' Southeast Fisheries Science Center (Garrison et al., 
2022). These models incorporate newer survey data from 2017-18 
including, notably, data from survey effort conducted during winter. 
Inclusion of winter data allows for increased temporal resolution of 
model predictions. These are the first density models that incorporate 
survey data collected after the DWH oil spill. New models were produced 
for all taxa other than Fraser's dolphin and rough-toothed dolphin, as 
the model authors determined that there were too few detections of 
these species to support model development. Therefore, we continue to 
rely on the Roberts et al. (2016) models for these two species.
    For species occurring in oceanic waters, the updated density models 
are based upon data collected during vessel surveys conducted in 2003-
04, 2009, and 2017-18. Survey effort was generally conducted in a 
survey region bounded by the shelf break (approximately the 200-m 
isobath) to the north and the boundary of the U.S. EEZ to the south. 
Separate models were created for species occurring in shelf waters 
(Atlantic spotted dolphin and bottlenose dolphin) based on seasonal 
aerial surveys conducted in 2011-12 and 2017-18. Based on water depth, 
the shelf models were used to predict acoustic exposures for these two 
species in Zones 2 and 3, and the oceanic models were used to predict 
exposures in Zones 4-7.
    As discussed above, the updated density modeling effort retains the 
previous approach of treating beaked whales and Kogia spp. as guilds, 
as sightings of these species are typically difficult to resolve to the 
species level. In addition, the model authors determined there to be 
too few sightings and/or too few sightings resolved to species level 
for the melon-headed whale, false killer whale, pygmy killer whale, and 
killer whale to produce individual species models. Instead, a single 
``blackfish'' model was developed to produce guild-level predictions 
for these species (Garrison et al., 2022).

Take Estimates

    Exposure estimates above Level A and Level B harassment criteria, 
originally developed by Zeddies et al. (2015, 2017a, 2017b) and updated 
by Weirathmueller et al. (2022) in association with the activity 
projections for the various annual effort scenarios, were generated 
based on the specific modeling scenarios (including source and survey 
geometry), i.e., 2D survey (1 x source array), 3D NAZ survey (2 x 
source array), 3D WAZ survey (4 x source array), coil survey (4 x 
source array).
    Level A Harassment--Here, we summarize acoustic exposure modeling 
results related to Level A harassment. For more detailed discussion, 
please see the 2018 Federal Register notice for the proposed rule and 
responses to public comment provided in the 2021 Federal Register 
notice for the final rule. Overall, there is a low likelihood of take 
by Level A harassment for any species, though the degree of this low 
likelihood is primarily influenced by the specific hearing group. For 
mid- and high-frequency cetaceans, potential auditory injury would be 
expected to occur on the basis of instantaneous exposure to peak 
pressure output from an airgun array while for low-frequency cetaceans, 
potential auditory injury would occur on the basis of the accumulation 
of energy output over time by an airgun array. For additional 
discussion, please see NMFS (2018) and discussion provided in the 2018 
notice of proposed rulemaking (83 FR 29212, June 22, 2018) and in the 
notice of issuance for the 2021 final rule (86 FR 5322; January 19, 
2021), e.g., 83 FR 29262; 86 FR 5354; 86 FR 5397. Importantly, the 
modeled exposure estimates do not account for either aversion or the 
beneficial impacts of the required mitigation measures.
    Of even greater import for mid-frequency cetaceans is that the 
small calculated Level A harassment zone size in conjunction with the 
properties of sound fields produced by arrays in the near field versus 
far field leads to a logical conclusion that Level A harassment is so 
unlikely for species in this hearing group as to be discountable. For 
all mid-frequency cetaceans, following evaluation of the available 
scientific literature regarding the auditory sensitivity of mid-
frequency cetaceans and the properties of airgun array sound fields, 
NMFS does not expect any reasonable potential for Level A harassment to 
occur. This issue was addressed in detail in the response to public 
comments provided in NMFS' notice of issuance for the rule (86 FR 5322, 
January 19, 2021; see 86 FR 5354). NMFS expects the potential for Level 
A harassment of mid-frequency cetaceans to be discountable, even before 
the likely moderating effects of aversion and mitigation are 
considered, and NMFS does not believe that Level A harassment is a 
likely outcome for any mid-frequency cetacean. Therefore, the updated 
modeling results provided by Weirathmueller et al. (2022) account for 
this by assuming that any estimated exposures above Level A harassment 
thresholds for mid-frequency cetaceans resulted instead in Level B 
harassment (as reflected in Table 6).
    As discussed in greater detail in the 2018 notice of proposed 
rulemaking (83 FR 29212, June 22, 2018), NMFS considered the 
possibility of incorporating quantitative adjustments within the 
modeling process to account for the effects of mitigation and/or 
aversion, as these factors would lead to a reduction in likely 
injurious exposure. However, these factors were ultimately not 
quantified in the modeling. In summary, there is too much inherent 
uncertainty regarding the effectiveness of detection-based mitigation 
to support any reasonable quantification of its effect in reducing 
injurious exposure, and there is too little information regarding the 
likely level of onset and degree of aversion to quantify this behavior 
in the modeling process. This does not mean that mitigation is not 
effective (to some degree) in avoiding incidents of Level A harassment, 
nor does it mean that aversion is not a meaningful real-world effect of 
noise exposure that should be expected to reduce the number of 
incidents of Level A harassment. As discussed in greater detail in 
responses to public comments provided in the 2021 notice of issuance 
for the final rule (86 FR 5322, January 19, 2021; see 86 FR 5353), 
there is ample evidence in the literature that aversion is one of the 
most common responses to noise exposure across varied species, though 
the onset and degree may be expected to vary across individuals and in 
different contexts. Therefore, NMFS incorporated a reasonable 
adjustment to modeled Level A harassment exposure estimates to account 
for aversion for low- and high-frequency species. That approach, which 
is retained here, assumes that an 80 percent reduction in modeled 
exposure estimates for Level A harassment for low- and high-frequency 
cetaceans is reasonable (Ellison et al.,

[[Page 928]]

2016) and likely conservative in terms of the overall numbers of actual 
incidents of Level A harassment for these species, as the adjustment 
does not explicitly account for the effects of mitigation. This 
adjustment was incorporated into the updated modeling results provided 
by Weirathmueller et al. (2022) and reflected in Table 6.
    Take Estimation Error--As discussed previously, in 2020 BOEM 
provided an update to the scope of their proposed action through 
removal of the area subject to leasing moratorium under GOMESA from 
consideration in the rule. In support of this revision, BOEM provided 
revised 5-year level of effort predictions and associated acoustic 
exposure estimates. BOEM's process for developing this information, 
described in detail in ``Revised Modeled Exposure Estimates,'' 
available online, was straightforward. Rather than using the PEIS's 10-
year period, BOEM provided revised levels of effort for a 5-year 
period, using Years 1-5 of the original level of effort projections. 
BOEM stated that the first 5 years were selected to be carried forward 
``because they were contiguous, they included the three years with the 
most activity, and they were the best understood in relation to the 
historical data upon which they are based.'' Levels of effort, shown in 
Table 1, were revised based on the basic assumption that if portions of 
areas are removed from consideration, then the corresponding effort 
previously presumed to occur in those areas also is removed from 
consideration. Projected levels of effort were reduced in each zone by 
the same proportion as was removed from each zone when BOEM reduced the 
scope of its proposed action, i.e., the levels of effort were reduced 
by the same zone-specific proportions shown in Table 1 in the notice of 
issuance for the final rule (86 FR 5322, January 19, 2021). Associated 
revised take estimates were provided by BOEM and evaluated in the final 
rule.
    While processing requests for individual LOAs under the rule using 
the methodology for developing LOA-specific take numbers presented in 
the rule, NMFS discovered discrepancies between the revised total take 
numbers provided by BOEM when addressing its revision to the scope of 
activity through removal of the GOMESA area and the underlying modeling 
results. (Note that the underlying modeling results are in the form of 
24-hr exposure estimates, specific to each species, zone, survey type, 
and season. These 24-hr exposure estimates can then be scaled to 
generate take numbers appropriate to the specific activity or, in the 
case of BOEM's petition for rulemaking, to the total levels of activity 
projected to occur across a number of years.)
    NMFS contacted BOEM regarding the issue in June 2021. Following an 
initial discussion, BOEM determined that when it reduced its scope of 
specified activity by removing the GOMESA moratorium area from the 
proposed action, it underestimated the level of take by inadvertently 
factoring species density estimates into its revised exposure estimates 
twice. Generally, this miscalculation caused BOEM to underestimate the 
total predicted exposures of species from all survey activities in its 
revision to the incidental take rule application, most pronouncedly for 
those species with the lowest densities. The practical effect of this 
miscalculation is that the full amount of activity for which BOEM 
sought incidental take coverage in its application cannot be authorized 
under the existing incidental take rule.
    In September 2021, BOEM provided corrected exposure estimates. 
These are available in BOEM's September 2021 ``Corrected Exposure 
Estimates'' letter, available online at: www.fisheries.noaa.gov/action/incidental-take-authorization-oil-and-gas-industry-geophysical-survey-activity-gulf-mexico. Following receipt of BOEM's letter containing 
corrected exposure estimates, NMFS requested additional information 
from BOEM, including a detailed written description of the process 
involved in producing the revised take numbers submitted in 2020, the 
error(s) in that process, and the process involved in correcting those 
numbers. BOEM provided the requested information in October 2021, 
including the following explanation.
    When calculating estimated takes for the 2020 revision to the scope 
of activity, BOEM multiplied the modeled number of animals above 
threshold per day of survey (Nz,s,t),\4\ for each type of survey in 
each zone, by the habitat-based density of the species in each zone 
(rz,t) \5\ and the number of days of effort for each survey and zone by 
year (LoEz,s,y) \6\. However, the species' habitat-based density had 
already been included in the modeled number of animals above threshold 
(Nz,s,t). The species' habitat-based density had therefore been 
factored in twice.
---------------------------------------------------------------------------

    \4\ Nz,s,t is the number of individuals of a species, t, 
expected above threshold for a given survey, s, in each zone, z. The 
number of individuals already includes the species' habitat-based 
density (z,t) for each species and zone.
    \5\ z,t is the habitat-based density for each species or 
taxonomic group, t, in each zone, z.
    \6\ LoEz,s,y is the level of effort in days per year, y, for 
each survey type, s, in each zone, z.
---------------------------------------------------------------------------


    [GRAPHIC] [TIFF OMITTED] TP05JA23.002
    
    Observing that the resultant numbers did not make sense, BOEM 
attempted to rectify the issue, by applying approximated species-
specific scaling factors (Ct).
[GRAPHIC] [TIFF OMITTED] TP05JA23.003

    The result of this approach was that errors of varying degrees were 
introduced to the BOEM-derived take numbers evaluated in the final 
rule. Although NMFS was unable to replicate the derivation of the 
species-specific scaling factors, or to adequately compare the 
erroneous BOEM-derived values to the values evaluated in NMFS' 2018 
proposed rule or to other published values, it remained clear that the 
take estimates were significantly underestimated for multiple species. 
Because of this, recalculation of appropriate take numbers was 
necessary.
    New Modeling--Once it became clear that NMFS would need to 
recalculate the take numbers in order to support the necessary 
correction and reanalysis under the rule, we recognized that two other 
primary pieces of new information should be considered.

[[Page 929]]

    As discussed previously, through NMFS' experience in implementing 
the 2021 final rule, it has become evident that operators are not 
currently using airgun arrays as large as the proxy array specified by 
BOEM for the original exposure modeling effort, and that the use of 
that 72-element, 8,000-in\3\ array as the proxy for generating LOA-
specific take estimates is unnecessarily conservative. As a result, 
operators applying 8,000-in\3\ modeled results to operations conducted 
with smaller airgun arrays have been inappropriately limited in the 
number of planned days of data acquisition when NMFS' small numbers 
limit has been reached. Therefore, independently of and prior to the 
above-described discovery and evaluation of BOEM's error, NMFS had 
already determined that it would be useful and appropriate to produce 
new modeling results associated with a more representative airgun 
array. In consultation with industry operators, NMFS identified 
specifications associated with a 32-element, 5,110 in\3\ array and 
contracted with the same modelers that produced the original acoustic 
exposure modeling (JASCO Applied Sciences) to conduct new modeling 
following the same approach and methodologies described in detail in 
Zeddies et al. (2015, 2017a) and provided for public review through 
NMFS' proposed rule (83 FR 29212, June 22, 2018). Specifically, JASCO 
has now produced new comprehensive modeling results for all evaluated 
survey types for the three different arrays described previously: (1) 
4,130-in\3\ array, described in detail in Zeddies et al. (2017b) 
(acoustic exposure results were provided for only six species in 
Zeddies et al. (2017b); full results are now available); (2) 5,110-
in\3\ array specified by NMFS and described in Weirathmueller et al. 
(2022); and (3) 8,000-in\3\ array described in detail by Zeddies et al. 
(2015, 2017a).
    Since the time of the original acoustic exposure modeling, JASCO 
has reviewed all species definition files and applied extensive updates 
for many species. These files define the species-specific parameters 
that control animat behavior during animal movement modeling. In 
particular, changes in the minimum and maximum depth preferences 
affected the coverage area for several species, which resulted in 
significant changes to some estimated exposures for some species.
    In addition, at the time NMFS determined it would conduct a 
rulemaking to address the corrected take estimates, NMFS was aware that 
new cetacean density modeling (including incorporation of new Rice's 
whale data) was nearing completion, in association with the BOEM-funded 
GoMMAPPS effort (see: www.boem.gov/gommapps). As a result, NMFS 
determined that this new information (updated acoustic exposure 
modeling and new cetacean density models) should be used in revising 
the 2021 final rule and is the basis for the analysis conducted herein. 
For purposes of the negligible impact analyses, NMFS uses the ``worst-
case'' (i.e., the maximum of the estimates from the three airgun array 
configurations/sizes) species-specific exposure modeling results. 
Specifically, for all species other than Rice's whale, these results 
are associated with the 8,000-in\3\ array. For the Rice's whale, 
modeling associated with the 5,110-in\3\ array produced larger exposure 
estimates (discussed below).
    Estimated instances of take, i.e., scenario-specific acoustic 
exposure estimates incorporating the adjustments to Level A harassment 
exposure estimates discussed here, are shown in Table 6. For 
comparison, Table 5 shows the estimated instances of take evaluated in 
the 2021 final rule. This information regarding total number of takes 
(with Level A harassment takes based on assumptions relating to mid-
frequency cetaceans in general as well as aversion), on an annual basis 
for 5 years, provides the bounds within which incidental take 
authorizations--LOAs--may be issued in association with this regulatory 
framework. Importantly, modeled results showed increases in total take 
estimates for four species, while the others decreased from those 
analyzed in the final rule.\7\
---------------------------------------------------------------------------

    \7\ Note that because of the new category of blackfish, there is 
uncertainty on any change in the take numbers for the individual 
species that comprise that category, though collectively the take 
numbers for all the blackfish remain within the levels previously 
analyzed.
---------------------------------------------------------------------------

    Typically, and especially in cases where PTS is predicted, NMFS 
anticipates that some number of individuals may incur temporary 
threshold shift (TTS). However, it is not necessary to separately 
quantify those takes, as it is unlikely that an individual marine 
mammal would be exposed at the levels and duration necessary to incur 
TTS without also being exposed to the levels associated with behavioral 
disruption. As such, NMFS expects any potential TTS takes to be 
captured by the estimated takes by behavioral disruption (discussed 
below).

    Table 5--Scenario-Specific Instances of Take (by Level A and Level B Harassment) and Mean Annual Take Levels Evaluated in the 2021 Final Rule \1\
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                            Year 1             Year 2             Year 3              Year 4              Year 5        Mean annual take
               Species               -------------------------------------------------------------------------------------------------------------------
                                         A        B         A        B         A        B         A         B          A        B         A        B
--------------------------------------------------------------------------------------------------------------------------------------------------------
Rice's whale........................       0         10       0          8       0          8       0            6       0          7       0          8
Sperm whale.........................       0     16,405       0     14,205       0     13,603       0        9,496       0     12,388       0     13,219
Kogia spp \2\.......................     371     10,383     337      9,313     310      8,542     209        6,238     314      8,318     308      8,559
Beaked whale \2\....................       0    191,566       0    162,301       0    158,328       0      111,415       0    142,929       0    153,308
Rough-toothed dolphin...............       0     30,640       0     27,024       0     25,880       0       19,620       0     23,219       0     25,277
Bottlenose dolphin..................       0    603,649       0    973,371       0    567,962       0    1,001,256       0    567,446       0    742,737
Clymene dolphin.....................       0     85,828       0     67,915       0     73,522       0       47,332       0     60,379       0     66,995
Atlantic spotted dolphin............       0    128,299       0    183,717       0    112,120       0      191,495       0    111,305       0    145,387
Pantropical spotted dolphin.........       0    478,490       0    436,047       0    391,363       0      311,316       0    395,987       0    402,641
Spinner dolphin.....................       0     75,953       0     71,873       0     61,098       0       48,775       0     64,357       0     64,411
Striped dolphin.....................       0     33,573       0     29,275       0     27,837       0       20,136       0     26,056       0     27,375
Fraser's dolphin....................       0      4,522       0      3,843       0      3,792       0        2,726       0      3,455       0      3,668
Risso's dolphin.....................       0     21,859       0     18,767       0     18,218       0       12,738       0     16,634       0     17,643
Melon-headed whale (Blackfish)......       0     55,813       0     47,784       0     46,584       0       32,581       0     42,224       0     44,997
Pygmy killer whale (Blackfish)......       0      8,079       0      6,964       0      6,764       0        4,970       0      6,277       0      6,611
False killer whale (Blackfish)......       0     16,165       0     13,710       0     13,604       0        9,664       0     12,269       0     13,082
Killer whale (Blackfish)............       0         60       0         56       0         50       0           42       0         52       0         52
Blackfish totals....................       0     80,117       0     68,514       0     67,002       0       47,257       0     60,822       0     64,742

[[Page 930]]

 
Short-finned pilot whale............       0     15,045       0      9,824       0     13,645       0        7,459       0      8,959       0     10,986
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ A and B refer to expected instances of take by Level A and Level B harassment, respectively, for Years 1-5. For Kogia spp., expected takes by Level
  A harassment represent modeled exposures adjusted to account for aversion. For the Rice's whale, no takes by Level A harassment are predicted to
  occur. Therefore, no adjustment to modeled exposures to account for aversion was necessary. For Kogia spp., exposures above Level A harassment
  criteria were predicted by the peak sound pressure level (SPL) metric. For the Rice's whale, the cumulative sound exposure level (SEL) metric is used
  to evaluate the potential for Level A harassment.
\2\ Kogia spp. includes dwarf and pygmy sperm whales. Beaked whales include Blainville's, Gervais', and Cuvier's beaked whales.


                Table 6--Updated Scenario-Specific Instances of Take (by Level A and Level B Harassment) and Mean Annual Take Levels \1\
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                            Year 1             Year 2             Year 3              Year 4              Year 5        Mean annual take
               Species               -------------------------------------------------------------------------------------------------------------------
                                         A        B         A        B         A        B         A         B          A        B         A        B
--------------------------------------------------------------------------------------------------------------------------------------------------------
Rice's whale........................       0         27       0         26       0         23       0           25       0         30       0         26
Sperm whale.........................       0     13,198       0     11,208       0     11,063       0        8,126       0     10,127       0     10,744
Kogia spp \2\.......................     192      7,272     172      6,301     165      6,104     118        4,581     164      5,776     162      6,007
Beaked whale \2\....................       0     29,415       0     26,955       0     23,551       0       17,307       0     23,060       0     24,058
Rough-toothed dolphin...............       0     38,535       0     33,878       0     32,241       0       25,290       0     29,373       0     31,863
Bottlenose dolphin..................       0    284,366       0    418,676       0    251,807       0      439,366       0    248,863       0    328,616
Clymene dolphin.....................       0     29,919       0     23,248       0     25,893       0       17,378       0     21,209       0     23,529
Atlantic spotted dolphin............       0     37,080       0     34,140       0     33,126       0       34,343       0     23,906       0     32,519
Pantropical spotted dolphin.........       0    293,390       0    259,831       0    243,888       0      189,147       0    236,651       0    244,581
Spinner dolphin.....................       0      4,618       0      4,456       0      3,704       0        3,147       0      4,101       0      4,006
Striped dolphin.....................       0     56,797       0     51,623       0     46,820       0       37,449       0     47,084       0     47,955
Fraser's dolphin....................       0     14,499       0     12,343       0     12,181       0        8,833       0     11,118       0     11,795
Risso's dolphin.....................       0      8,146       0      6,939       0      6,787       0        4,834       0      6,176       0      6,576
Blackfish \2\.......................       0     67,509       0     57,010       0     56,860       0       40,787       0     51,138       0     54,661
Short-finned pilot whale............       0     14,330       0      9,694       0     12,836       0        7,232       0      8,734       0     10,565
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ A and B refer to expected instances of take by Level A and Level B harassment, respectively, for Years 1-5. Expected takes by Level A harassment
  represent modeled exposures adjusted to account for aversion. For the Rice's whale, this adjustment means that no takes by Level A harassment are
  predicted to occur. For Kogia spp., exposures above Level A harassment criteria were predicted by the peak SPL metric. For the Rice's whale, the
  cumulative SEL metric is used to evaluate the potential for Level A harassment.
\2\ Kogia spp. includes dwarf and pygmy sperm whales. Beaked whales include Blainville's, Gervais', and Cuvier's beaked whales. Blackfish includes melon-
  headed whale, false killer whale, pygmy killer whale, and killer whale.

Discussion of Estimated Take

    Differences between the estimated instances of take evaluated in 
the 2021 final rule (Table 5) and those evaluated herein (Table 6) may 
be attributed to multiple factors. Due to the confounding nature of 
these factors, it is challenging to attribute species-specific 
differences by degree to any particular factor. These factors include: 
(1) BOEM errors in calculating estimated take in support of its 
revision of scope for the 2021 final rule, which are related to 
species-specific density values by zone, as well as to species-specific 
``correction factors'' developed by BOEM; (2) JASCO revisions to 
species definition files governing animat behavior during animal 
movement modeling; and (3) new density information for all species 
other than Fraser's dolphin and rough-toothed dolphin. In addition, for 
the Rice's whale, propagation modeling of a new array specification 
produced the greatest values for estimated instances of take. While it 
is difficult to attribute species-specific changes to specific factors, 
we do know that the correction of the BOEM error could only result in 
take number increases from the 2021 final rule, while density changes 
and species definition file changes could result in either increases or 
decreases in take estimates. NMFS has addressed BOEM's error to the 
extent possible in the discussion provided previously (see Take 
Estimation Error, wherein we relate BOEM's explanation of that error).
    Regarding the species characteristics used in the new modeling, as 
discussed above, all species behavior files were reviewed by JASCO 
prior to the new modeling, and many had extensive updates. In 
particular, changes in the minimum and maximum depth preferences 
affected the coverage area for several species, which resulted in 
changes to some species exposures.
    New modeling for the smaller, 5,110-in\3\ array illustrated that 
the larger array is not necessarily always more impactful. Free-field 
beam patterns are different for the arrays as are the tow depths. The 
5,110-in\3\ array was specified as being towed at 12 m depth (following 
typical usage observed by NMFS through review of LOA applications), 
while the other arrays are assumed to use an 8-m tow depth (assumptions 
regarding source specifications were made by BOEM as part of its 
original petition for rulemaking). The depth at which a source is 
placed influences the interference pattern caused by the direct and 
sea-surface reflected paths (the ``Lloyd's mirror'' effect). The 
destructive interference from the sea-surface reflection is generally 
greater for shallow tow depths compared to deeper tow depths. In 
addition, interactions between source depth, beam pattern geometry, 
source frequency content, the environment (e.g., bathymetry and sound 
velocity profile), and different seeding depths and behaviors can give 
unexpected results. For example, while the larger array may have the 
longest range for a particular isopleth (sound contour), the overall 
sound field coverage area was found to have greater asymmetry as a 
result of the above-mentioned interactions.
    While the larger array did produce greater predicted exposures for 
all species, with the exception of Rice's whales, the differences 
between predicted exposure estimates for the two larger arrays was not 
as great as may have been expected on the basis of total

[[Page 931]]

array volume alone. The 5,110- and 8,000-in\3\ arrays were often 
similar in terms of predicted exposures, although the beam patterns 
were quite different. For arrays of airgun sources, the chamber volume 
or the total array volume is not the only meaningful variable. Although 
it is true that a source with a larger volume is generally louder, in 
practice this only applies largely to single sources or small arrays of 
sources and was not the case for the considered arrays. As discussed 
above, array configuration, tow depth, and bathymetry were significant 
factors. For example, the 8,000-in\3\ array generally had a more 
directional beam pattern than the 4,130- or 5,110-in\3\ arrays. The 
vertical structure of the sound field combined with different species' 
dive depth and surface intervals was important as well. Differences in 
estimated take numbers for the 2021 final rule and this proposed rule, 
i.e., differences between Tables 5 and 6, are shown in Table 7.

                                Table 7--Differences in Estimated Take Numbers, 2021 Final Rule to 2022 Proposed Rule \1\
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                                                                            Mean annual
                         Species                              Year 1          Year 2          Year 3          Year 4          Year 5           take
--------------------------------------------------------------------------------------------------------------------------------------------------------
Rice's whale............................................              17              18              15              19              23              18
Sperm whale.............................................         (3,207)         (2,997)         (2,540)         (1,370)         (2,261)         (2,475)
Kogia spp.\2\ (Level A).................................           (179)           (165)           (145)            (91)           (150)           (146)
Kogia spp. (Level B)....................................         (3,111)         (3,012)         (2,438)         (1,657)         (2,542)         (2,552)
Beaked whale............................................       (162,151)       (135,346)       (134,777)        (94,108)       (119,869)       (129,250)
Rough-toothed dolphin...................................           7,895           6,854           6,361           5,670           6,154           6,586
Bottlenose dolphin......................................       (319,283)       (554,695)       (316,155)       (561,890)       (318,583)       (414,121)
Clymene dolphin.........................................        (55,909)        (44,667)        (47,629)        (29,954)        (39,170)        (43,466)
Atlantic spotted dolphin................................        (91,219)       (149,577)        (78,994)       (157,152)        (87,399)       (112,868)
Pantropical spotted dolphin.............................       (185,100)       (176,216)       (147,475)       (122,169)       (159,336)       (158,060)
Spinner dolphin.........................................        (71,335)        (67,417)        (57,394)        (45,628)        (60,256)        (60,405)
Striped dolphin.........................................          23,224          22,348          18,983          17,313          21,028          20,580
Fraser's dolphin........................................           9,977           8,500           8,389           6,107           7,663           8,127
Risso's dolphin.........................................        (13,713)        (11,828)        (11,431)         (7,904)        (10,458)        (11,067)
Blackfish \3\...........................................        (12,608)        (11,504)        (10,142)         (6,470)         (9,684)        (10,081)
Short-finned pilot whale................................           (715)           (130)           (809)           (227)           (225)            (421
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ Parentheses indicate negative values.
\2\ Level A harassment is not predicted to occur for any species other than the Kogia spp.
\3\ Values presented for blackfish represent the difference between the estimated take number presented in this rule for this group generically and the
  sum of the species-specific values evaluated in the 2021 final rule.

    NMFS cautions against interpretation of the changes presented in 
Table 7 at face value for a variety of reasons. First, reasons for the 
differences are difficult to interpret, as discussed in detail in the 
foregoing. Second, the meaning of the differences in terms of impacts 
to the affected species or stocks is similarly not as straightforward 
as may be indicated by the magnitude and direction of the differences. 
Differences in estimated take are, in part, the result of the 
introduction of new density data, which also provides new model-
predicted abundance estimates. Our evaluation under the MMPA of the 
expected impacts of the predicted take events is substantially reliant 
on comparisons of the expected take to the predicted abundance. See 
discussion of our evaluation of severity of impact (one prong of 
analysis) in Negligible Impact Analysis and Determinations. The 
severity of the predicted taking is understood through the estimates' 
relationship to predicted zone-specific abundance values, and so the 
absolute differences presented in Table 7 are not alone informative in 
that regard.
    Overall, NMFS has determined, to the extent possible, that aside 
from the confounding effect of BOEM's calculation errors, differences 
between the current and prior results for the 8,000-in\3\ array are 
primarily attributable to differences in species density along with 
changes in the species behavior files, in particular minimum and 
maximum animat seeding depths.

Level B Harassment

    NMFS has determined the values shown in Table 6 are a reasonable 
estimate of the maximum potential instances of take that may occur in 
each year of the regulations (more specifically, each of these 
``takes'' representing a day in which one individual is exposed above 
the Level B harassment criteria, even if only for minutes). However, 
these take numbers do not represent the number of individuals expected 
to be taken, as they do not consider the fact that certain individuals 
may be exposed above harassment thresholds on multiple days. 
Accordingly, as described in the 2018 notice of proposed rulemaking, 
NMFS developed an approach to inform two important parts of the 
analyses, both better understanding a closer approximation of the 
number of individuals of each species or stock that may be taken within 
a survey, and understanding the degree to which individuals of each 
species or stock may be more likely to be repeatedly taken across 
multiple days within a year.
    In summary, comparing the results of modeling simulations that more 
closely match longer survey durations (30 days) to the results of 24-
hour take estimates scaled up to 30 days (as the instances of take in 
Table 6 were calculated) provides the comparative ratios of the numbers 
of individuals taken/calculated (within a 30-day survey) to instances 
of take, in order to better understand the comparative distribution of 
exposures across individuals of different species. These products are 
used to inform a better understanding of the nature in which 
individuals are taken across the multiple days of a longer duration 
survey given the different behaviors that are represented in the animat 
modeling and may appropriately be used in combination with the 
calculated instances of take to predict the number of individuals taken 
for surveys of similar duration, in order to support evaluation of take 
estimates in requests for Letters of Authorization under the ``small 
numbers'' standard, which is based on the number of individuals taken. 
A detailed discussion of this approach was provided in the 2018 notice 
of proposed rulemaking. As NMFS retains without change this ``scalar 
ratio'' approach to approximating the number of individuals taken, both 
here (see

[[Page 932]]

Negligible Impact Analysis and Determinations) and in support of the 
necessary small numbers determination on an LOA-specific basis, we do 
not repeat the discussion but refer the reader to previous Federal 
Register notices. Application of the re-scaling method reduced the 
overall magnitude of modeled takes for all species by a range of 
slightly more than double up to ten-fold (Table 8).
    These adjusted take numbers, representing a closer approximation of 
the number of individuals taken (shown in Table 8), provide a more 
realistic basis upon which to evaluate severity of the expected taking. 
Please see the Negligible Impact Analysis and Determinations section, 
later in this document, for additional detail. It is important to 
recognize that while these scaled numbers better reflect the number of 
individuals likely to be taken within a single 30-day survey than the 
number of instances in Table 6, they will still overestimate the number 
of individuals taken across the aggregated GOM activities, because they 
do not correct for (i.e., further reduce take to account for) 
individuals exposed to multiple surveys or fully correct for 
individuals exposed to surveys significantly longer than 30 days.
    As noted in the beginning of this section and in the Small Numbers 
section, using modeled instances of take (Table 6) and the method used 
here to scale those numbers allows one to more accurately predict the 
number of individuals that will be taken as a result of exposure to one 
survey and, therefore, these scaled predictions should be considered in 
requests for LOAs to assess whether a resulting LOA would meet the 
small numbers standard. However, for the purposes of ensuring that the 
take authorized pursuant to all issued LOAs is within the scope of the 
analysis conducted to support the negligible impact finding in this 
rule, authorized instances of take (which are the building blocks of 
the analysis) also must be assessed. Specifically, reflecting Table 6 
and what has been analyzed, the total take authorized for any given 
species or stock over the course of the five years covered under these 
regulations should not exceed the sum of the five years of take 
indicated for the five years in that table. Additionally, in any given 
year, the take of any species should not exceed the highest annual take 
listed for any of the five years.

                                Table 8--Expected Total Take Numbers, Scaled \1\
----------------------------------------------------------------------------------------------------------------
             Species                  Year 1          Year 2          Year 3          Year 4          Year 5
----------------------------------------------------------------------------------------------------------------
Rice's whale....................               5               5               4               5               6
Sperm whale.....................           5,583           4,741           4,679           3,437           4,284
Kogia spp.......................           2,334           2,022           1,959           1,470           1,854
Beaked whale....................           2,971           2,722           2,379           1,748           2,329
Rough-toothed dolphin...........          11,060           9,723           9,253           7,258           8,430
Bottlenose dolphin..............          81,613         120,160          72,269         126,098          71,424
Clymene dolphin.................           8,587           6,672           7,431           4,987           6,087
Atlantic spotted dolphin........          10,642           9,798           9,507           9,856           6,861
Pantropical spotted dolphin.....          84,203          74,571          69,996          54,285          67,919
Spinner dolphin.................           1,325           1,279           1,063             903           1,177
Striped dolphin.................          16,301          14,816          13,437          10,748          13,513
Fraser's dolphin................           4,161           3,543           3,496           2,535           3,191
Risso's dolphin.................           2,403           2,047           2,002           1,426           1,822
Blackfish.......................          19,915          16,818          16,774          12,032          15,086
Short-finned pilot whale........           4,227           2,860           3,787           2,134           2,576
----------------------------------------------------------------------------------------------------------------
\1\ Scalar ratios were applied to values in Table 6 as described in the 2018 notice of proposed rulemaking to
  derive scaled take numbers shown here.

Proposed Mitigation

``Least Practicable Adverse Impact'' Standard

    Under section 101(a)(5)(A) of the MMPA, NMFS must set forth the 
permissible methods of taking pursuant to such activity, and other 
means of effecting the least practicable adverse impact on such species 
or stock and its habitat, paying particular attention to rookeries, 
mating grounds, and areas of similar significance, and on the 
availability of such species or stock for subsistence uses (hereinafter 
referred to as ``LPAI'' or ``least practicable adverse impact''). NMFS 
does not have a regulatory definition for least practicable adverse 
impact. However, NMFS' implementing regulations require applicants for 
incidental take authorizations to include information about the 
availability and feasibility (economic and technological) of equipment, 
methods, and manner of conducting such activity or other means of 
effecting the least practicable adverse impact upon the affected 
species or stocks and their habitat (50 CFR 216.104(a)(11)). We note 
that in some cases, certain mitigation may be necessary in order to 
make a ``negligible impact'' finding for an affected species or stock, 
which is a fundamental requirement of issuing an authorization--in 
these cases, consideration of practicability may be a lower priority 
for decision-making if impacts to marine mammal species or stocks would 
not be negligible in the measure's absence. In the Mitigation section 
of the 2021 final rule, NMFS included a detailed description of our 
interpretation of the LPAI standard and how it should be applied, and 
we refer readers to that discussion.
    In summary, in evaluating how mitigation may or may not be 
appropriate to ensure the least practicable adverse impact on species 
or stocks and their habitat, as well as subsistence uses where 
applicable, NMFS considers two primary factors:
    (1) The manner in which, and the degree to which, implementation of 
the potential measure(s) is expected to reduce adverse impacts to 
marine mammal species or stocks, their habitat, and their availability 
for subsistence uses (where relevant). This analysis considers such 
things as the nature of the potential adverse impact (such as 
likelihood, scope, and range), the likelihood that the measure will be 
effective if implemented, and the likelihood of successful 
implementation.
    (2) The practicability of the measures for applicant 
implementation. Practicability of implementation may consider such 
things as cost, impact on

[[Page 933]]

activities, personnel safety, and practicality of implementation.

Application of the Least Practicable Adverse Impact Standard in This 
Action

    In carrying out the MMPA's mandate for this action, NMFS applies 
the previously described context-specific balance between the manner in 
which and the degree to which measures are expected to reduce impacts 
to the affected species or stocks and their habitat and practicability 
for operators. The effects of concern (i.e., those with the potential 
to adversely impact species or stocks and their habitat), addressed 
previously in the Potential Effects of the Specified Activity on Marine 
Mammals and Their Habitat section of the 2018 notice of proposed 
rulemaking, include auditory injury, severe behavioral reactions, 
disruptions of critical behaviors, and to a lesser degree, masking and 
impacts on acoustic habitat (see discussion of this concept in the 
``Anticipated Effects on Marine Mammal Habitat'' section in the 2018 
notice of proposed rulemaking).
    Our prior rulemaking for the 2021 final rule focused on measures 
with proven or reasonably presumed ability to avoid or reduce the 
intensity of acute exposures that have potential to result in these 
anticipated effects with an understanding of the drawbacks or costs of 
these requirements. In addition, we evaluated time-area restrictions 
that would avoid or reduce both acute and chronic impacts, including 
potential restrictions that were removed from consideration in the 
final rule as a result of BOEM's change to the scope of the action. To 
the extent of the information available to NMFS, we considered 
practicability concerns, as well as potential undesired consequences of 
the measures, e.g., extended periods using the acoustic source due to 
the need to reshoot lines. NMFS also recognized that instantaneous 
protocols, such as shutdown requirements, are not capable of avoiding 
all acute effects, are not suitable for avoiding many cumulative or 
chronic effects, and do not provide targeted protection in areas of 
greatest importance for marine mammals. Therefore, in addition to a 
basic suite of seismic mitigation protocols, we also considered 
measures that may or may not be appropriate for other activities (e.g., 
time-area restrictions specific to the surveys discussed herein).
    In order to satisfy the MMPA's least practicable adverse impact 
standard, NMFS' 2021 rule evaluated a suite of basic mitigation 
protocols that are required regardless of the status of a stock. 
Additional or enhanced protections were required for species whose 
stocks are in particularly poor health and/or are subject to some 
significant additional stressor that lessens that stock's ability to 
weather the effects of the specified activities without worsening its 
status. NMFS' evaluation process was described in detail in the 
original proposed rule (83 FR 29212, June 22, 2018), and mitigation 
requirements included in the incidental take regulations were fully 
described in the notice of issuance for the final rule (86 FR 5322, 
January 19, 2021).
    For this proposed rule, NMFS considered additional mitigation for 
this action in light of the updated take estimates. Based on that 
evaluation, we have preliminarily determined that the current 
regulations promulgated under the 2021 final rule satisfy the least 
practicable adverse impact standard, and therefore, we do not propose 
changes to those regulations. Because the proposed mitigation 
requirements for this action are the same as those described in the 
notice of issuance for the final rule (86 FR 5322, January 19, 2021), 
we do not repeat the description of the required mitigation.
    Below, we include additional discussion supporting the least 
practical adverse impact finding as it relates to Rice's whales, given 
the increase in estimated take relative to the 2021 final rule and 
other new information. For other species, despite slight increases in 
estimated take (for three species) and increases in evaluated risk (for 
other species) since the 2021 final rule (see Negligible Impact 
Analysis and Determinations), there are no known specific areas of 
particular importance to consider for time-area restrictions, and no 
changes to our prior analysis for the sufficiency of the existing 
standard operational mitigation requirements to effect the least 
practicable adverse impact on the affected species or stocks and their 
habitat. (We also note that NMFS' 2018 proposed rule made this 
determination even in the context of significantly higher takes, as 
well as evaluated risk.)
    Rice's Whale--As discussed previously in this document, the Rice's 
whale ``core habitat area'' considered in the 2018 notice of proposed 
rulemaking was designated as between the 100- and 400-m isobaths, from 
87.5[deg] W to 27.5[deg] N (Figure 3). That core habitat area was 
considered in the 2018 notice of proposed rulemaking as a potential 
restriction area, but because the area was entirely located in the 
GOMESA moratorium area removed from consideration for the rule, the 
core habitat area was no longer relevant for consideration as 
mitigation in the 2021 final rule.
    As described previously, NMFS has developed an updated description 
of Rice's whale core habitat area (Figure 3). The updated process for 
describing ``core habitat'' incorporated a more precautionary approach 
to addressing uncertainty associated with both the location of observed 
whales as well as to account for the possible movement whales could 
make in any one direction from an observed sighting, i.e., inclusion of 
the 30-km total buffer discussed previously. As a result of the 
addition of this buffer to the newly defined polygon encompassing all 
whale observations and tag locations in the core habitat region, the 
updated core habitat area now overlaps slightly within the area covered 
through the scope of the rule. Approximately 5 percent of the updated 
core habitat area now overlaps the geographic scope of the rule (as 
defined by the petitioner, BOEM). In addition, new information 
regarding potential Rice's whale occurrence outside of the core habitat 
area, based on passive acoustic detections (Soldevilla et al., 2022), 
is now available. Information supporting the importance of a core 
habitat area for Rice's whales has not changed from the 2021 final 
rule. We provide discussion of this information in the following 
paragraphs.
BILLING CODE 3510-22-P

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[GRAPHIC] [TIFF OMITTED] TP05JA23.004

BILLING CODE 3510-22-C
    Rice's whales form a small and resident population in the 
northeastern GOM, with a highly restricted geographic range and a very 
small population abundance--determined by the status review team to be 
``at or below the near-extinction population level'' (Rosel et al., 
2016). Aside from the restricted distribution and small population, the 
whales face a significant suite of anthropogenic threats, one of which 
is noise produced by airgun surveys.
    While various population abundance estimates are available (e.g., 
Garrison et al., 2022; Hayes et al., 2020; Roberts et al., 2016; Dias 
and Garrison, 2016), the population abundance was almost certainly less 
than 100 prior to the DWH oil spill. NOAA estimated that, as a result 
of that event, 48 percent of the population may have been exposed to 
DWH oil, with 17 percent killed and 22 percent of females experiencing 
reproductive failure. The best estimate for maximum population 
reduction was 22 percent, with an estimated 69 years to recovery (to 
the precarious status prior to the DWH oil spill) (DWH MMIQT, 2015). It 
is considered likely that Rice's whale habitat previously extended to 
shelf and slope areas of the western and central GOM similar to where 
they are found now in the eastern GOM, and that anthropogenic 
activity--largely energy exploration and production--concentrated in 
those areas could have resulted in habitat abandonment (Reeves et al., 
2011; Rosel and Wilcox, 2014). Further, the population exhibits very 
low levels of genetic diversity, and based on significant genetic 
mitochondrial DNA divergence from Bryde's whales worldwide, the former 
GOM Bryde's whale was recognized as a separate species (Rosel and 
Wilcox, 2014; Rosel et al., 2021).
    The small population size, restricted range, and low genetic 
diversity alone place these whales at significant risk of extinction 
(IWC, 2017), which has been exacerbated by the effects of the DWH oil 
spill. Additionally, Rice's whale dive and foraging behavior places 
them at heightened risk of being struck by vessels and/or entangled in 
fishing gear (Soldevilla et al., 2017). NMFS considered a restriction 
within core habitat (as previously defined) to protect Rice's whales 
because of their hearing sensitivity in the lower frequency range 
(which makes them generally more susceptible to incurring effects from 
airgun noise than other taxa in the GOM); the potential impacts to 
important behavioral functions such as feeding, breeding, and raising 
young; their dangerously low population size; and other issues 
discussed previously.
    NMFS' 2018 proposed rule proposed a seasonal restriction on survey 
activity in the core habitat area considered therein, but also 
requested comment on a range of alternatives (including a year-round 
restriction). That proposal, and associated alternatives, were offered 
for public comment in context of the significantly greater predicted 
take numbers evaluated in the 2018 proposed rule and the complete 
overlap of the original project area with the core habitat area prior 
to the removal of the

[[Page 935]]

GOMESA area. While the take numbers presented here are greater than 
those evaluated in the 2021 final rule, they are significantly lower in 
relation to those in the 2018 proposed rule. Predicted take numbers 
across the three analyses are shown in Table 9. In addition, the 2018 
proposed rule analysis included up to several instances of Level A 
harassment per year, in the form of permanent threshold shift. In 
contrast, neither the 2021 final rule nor this proposed rule include 
predicted instances of Level A harassment.

                                Table 9--Comparison of Analyzed Rice's Whale Take
----------------------------------------------------------------------------------------------------------------
                                                                   2018 proposed    2021 final     2022 proposed
                                                                       rule            rule            rule
----------------------------------------------------------------------------------------------------------------
5-year total....................................................           2,310              39             132
Annual maximum..................................................             572              10              30
----------------------------------------------------------------------------------------------------------------

    As noted above, the proposed restriction, and alternatives thereto, 
were no longer relevant due to the changed geographic scope of the 2021 
final rule. We now consider the effectiveness and practicability of a 
potential restriction covering the approximately 5 percent of core 
habitat (updated) that overlaps with the geographic scope of this rule, 
as well as of other areas that could be considered important habitat 
for Rice's whales.
    As discussed in the 2018 proposed rule, a restriction on (or 
absence of) survey activity in core habitat would be expected to 
protect Rice's whales and their habitat through the alleviation or 
minimization of a range of airgun effects, both acute and chronic, that 
could otherwise accrue to impact the reproduction or survival of 
individuals in the core habitat area. The absence of survey activity in 
the area would not only largely avoid Level B harassment of Rice's 
whales, but also very importantly minimize other acoustic effects such 
as masking and loss of communication space.
    However, the significant concern that led NMFS to consider such a 
restriction through the 2018 proposed rule has largely been alleviated 
through the reduction in predicted take numbers. Although predicted 
take numbers have increased relative to the 2021 final rule (annual 
average Level B harassment events of 26 versus 8), expected takes 
remain significantly less than those considered in that 2018 analysis 
(annual average of 462, plus some expected potential for Level A 
harassment to occur)--an almost 18-fold reduction. Moreover, the 
functional absence of survey activity in the eastern GOM, and within 
Rice's whale core habitat, means that the anticipated protection 
afforded by the previously proposed restriction has been substantively 
achieved by virtue of the change in scope for the 2021 final rule 
(which is unchanged for this proposed action). Although the updated 
core habitat area now slightly overlaps with the geographic scope of 
the rule (5 percent of defined core habitat overlaps the area 
considered as part of this rule), we note that the update to the core 
habitat description is not the result of additional Rice's whale 
sightings necessitating the expanded description, but rather through 
the incorporation of additional precaution in defining the area within 
which existing Rice's whale sightings and tag locations suggest that 
whales could occur (i.e., a 30-km buffer has been added, as discussed 
in the Description of Marine Mammals in the Area of the Specified 
Activities section). As a result of these considerations, NMFS has 
determined that a restriction on survey activity within the portion of 
the updated core habitat area that occurs within scope of the rule is 
not warranted. NMFS requests comment on this determination.
    Although the core habitat area is largely no longer relevant under 
the updated geographic scope of the specified activity and this rule, 
the discussion above is still important to describe NMFS' work to 
identify appropriate mitigation in this rulemaking. In addition, we 
acknowledge that some whales are likely to be present at locations 
other than within the core habitat area, and we considered additional 
information in order to evaluate whether a different closure area may 
be warranted, including central and western GOM areas within the same 
general 100-400 m depth range known to be occupied by Rice's whales in 
the northeastern GOM.
    Outside of the core habitat area, a NOAA survey reported 
observation of a Rice's whale in the western GOM in 2017 (NMFS, 2018). 
There had not previously been a verified sighting of a Rice's whale in 
the western GOM, and given the importance of this observation, 
additional survey effort was conducted in an attempt to increase effort 
in the area. However, no additional sightings were recorded. (Note that 
there were two sightings of unidentified large baleen whales in 1992 in 
the western GOM, recorded as Balaenoptera sp. or Bryde's/sei whale. 
Prior to the 2017 sighting, which was confirmed as a Rice's whale, it 
was considered unlikely that the 1992 sightings were of Rice's whales.) 
In addition, there are occasional sightings by protected species 
observers (PSOs) of baleen whales in the GOM. These sightings are 
typically of other, vagrant species, are in habitat considered 
unsuitable for Rice's whale (e.g., deep water), and/or are unresolved 
taxonomically. Of 13 unconfirmed Bryde's-like whale PSO sightings that 
occurred along the northwestern GOM shelf-break from 2010-2014, Rosel 
et al. (2021) found that there were 4 potential Rice's whale 
observations (i.e., that could neither be verified nor ruled out as 
Rice's whale sightings), all within the 200-400 m isobaths.
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    In addition, Soldevilla et al. (2022) deployed autonomous passive 
acoustic recorders at five sites along the northwestern GOM shelf break 
in predicted Rice's whale habitat (Roberts et al., 2016) for 1 year 
(2016-2017) to (1) determine if Rice's whales occur in waters beyond 
the northeastern GOM and, if so, (2) evaluate their seasonal occurrence 
and site fidelity at the five northwestern GOM sites. Over the course 
of the 1-year study, sporadic, year-round recordings of calls assessed 
as belonging to Rice's whales were made south of Louisiana within 
approximately the same depth range (200-400 m), indicating that some 
Rice's whales occurred regularly in waters beyond their known core 
habitat in the northeastern GOM during the study period. Based on the 
detection range of the sonobuoys and acoustic monitors used in the 
study, actual occurrence could be in water depths up to 500 m (M. 
Soldevilla, pers. comm.) (though the deepest confirmed Rice's whale 
sighting was in 408 m water depth). Data were successfully collected at 
four of the five sites; of these four sites, Rice's whale calls were 
detected at three. Detection of calls ranged from 1 to 16 percent of 
total days at the three sites. Calls were present in all seasons at two 
sites, with no obvious seasonality, and it remains unknown whether 
animals are moving between the northwestern and northeastern sites or 
whether these represent different groups of animals (Soldevilla et al., 
2022). The rate of call detections throughout the year is considerably 
higher in the eastern GOM than at the western GOM site where calls were 
most commonly detected, with at least 8.3 calls/hour among four eastern 
GOM sites over 110 deployment days (Rice et al., 2014) compared to 0.27 
calls/hour over the 299-day deployment at the western GOM site where 
calls were detected most frequently. Approximately 2,000 total calls 
were detected at the site over 10 months, compared to more than 66,000 
total detections at the eastern GOM deployment site over 11 months 
(approximately 30 times more calls detected at the eastern GOM site) 
(Soldevilla et al., 2022). Although it should be noted that ambient 
noise conditions were higher at the western GOM site, influencing 
maximum detection range, this difference in conditions would be 
expected to result in only 4-8 times as many call detections if all 
other factors (including presence and number of whales) were consistent 
(versus 30 times as many detections). Overall, the study authors assess 
that there seem to be fewer whales or more sparsely spaced whales in 
the western GOM compared to the eastern GOM, with calls present on 
fewer days, lower call detection rates, and far fewer call detections 
in the western GOM.
    The passive acoustic data discussed above provide evidence for the 
persistent occurrence of at least some individual Rice's whales over a 
broader distribution in the GOM than previously understood. However, 
overall, Rice's whale observations remain consistently located within 
the eastern GOM core habitat area, with few whales sighted

[[Page 937]]

elsewhere despite a large amount of dedicated cetacean survey effort 
that covered both continental shelf and oceanic waters. Whales have 
been sighted in the core habitat area in all seasons, and all 
indications are that the whales inhabit this area year-round as a 
resident population. A tagged whale remained within the area for the 
entire time the tag was active (38 days). Therefore, while we expect 
that some individual Rice's whales occur outside the core habitat area 
and/or that whales from the eastern GOM occasionally travel outside the 
area, the currently available data support NMFS' determination that the 
area currently considered core habitat is an adequate representation.
    NMFS produced a regulatory impact analysis (RIA) in support of the 
2018 proposed rule, which evaluated potential costs associated with a 
range of area-based activity restrictions (available online at: 
www.fisheries.noaa.gov/action/incidental-take-authorization-oil-and-gas-industry-geophysical-survey-activity-gulf-mexico). Although that 
analysis did not directly evaluate a potential closure of the area that 
might be considered here as a Rice's whale protected area, i.e., 
potentially suitable habitat in the central and western GOM outside of 
known Rice's whale core habitat, it provided a useful framework for 
considering practicability in an assessment of potential restrictions 
in the northeastern GOM. That analysis concluded that the direct 
compliance costs of the rule would represent a small increase in oil 
and gas development costs overall and, therefore, would be unlikely to 
result in materially reduced oil and gas activities in the GOM. 
However, the analysis suggested that the analyzed seasonal and year-
round area closures would have the potential to generate reductions in 
leasing, exploration, and subsequent development activity. Although the 
report cautioned that its conclusions were subject to substantial 
uncertainty, it provided several factors that the likelihood of 
ultimate impacts to oil and gas production as a result of delays in 
data collection could be expected to depend upon: (1) oil and gas 
market conditions; (2) the relative importance of the closure area to 
oil and gas production; (3) the state of existing data covering the 
area; and (4) the duration of the closure. NMFS cannot predict factor 
(1) and does not have complete information regarding factor (3) (though 
the analysis provides that new surveys are expected to be required to 
facilitate efficient exploration and development decisions). We can, 
however, more adequately predict the effects of factors (2) and (4) on 
the impact of any closure.
    Historical Rice's whale habitat, which is also generally modeled as 
being suitable habitat (Roberts et al., 2016; Garrison et al. 2022), 
generally consists of the aforementioned strip of continental shelf 
waters within the 100-400 m isobaths. Salinity and surface water 
velocity are also likely predictive of potential Rice's whale 
occurrence (Garrison et al., 2022), but these more dynamic variables 
are less useful in delineating a potential area of importance than the 
static depth variable. Within this GOM-wide depth range, we focus on 
the area where Soldevilla et al. (2022) recorded Rice's whale calls as 
being of interest for a potential restriction. This area lies within 
the central GOM, where the vast majority of survey effort during NMFS' 
experience in implementing this rule has occurred. The 2018 proposed 
rule RIA considered the economic impacts of a prospective closure area 
in deeper waters of the central GOM. The evaluated area was designed to 
be of benefit to sperm whales and beaked whales, which are found in 
deep water, and more activity is projected to occur in deep water than 
in the shelf-break waters where Rice's whales are expected to be found. 
As such, the RIA analysis likely overestimates the potential impacts of 
a central GOM closure within a portion of the shelf waters favored by 
Rice's whales in their known habitat. However, the analysis of deep-
water closures in the central GOM suggested the possibility that the 
closure could affect the broader contribution of the GOM to U.S. oil 
and gas activity, with shifts in effort potentially reducing domestic 
oil and gas production, industry income, and employment, ultimately 
concluding that the economic impact on the regional economy could be 
significant. A key consideration in this finding relates to factor (4), 
as the analyzed closure was year-round. Similarly, there is no 
information to support a temporal component to design of a potential 
Rice's whale closure and, therefore, a closure would appropriately be 
year-round. As operators have no ability to plan around a year-round 
closure, this aspect exacerbates the potential for effects on oil and 
gas productivity in the GOM.
    In summary, the foregoing preliminarily supports (1) that there is 
no clearly defined important habitat with known occupation and usage 
patterns outside the existing core habitat area that would 
appropriately be subject to a restriction on survey activity; and (2) 
the potential that a central GOM closure would have significant 
economic impacts. During implementation of the existing rule, NMFS has 
issued three LOAs in association with surveys occurring roughly within 
this area of the central GOM (87 FR 55790, October 1, 2022; 87 FR 
43243, July 20, 2022; 87 FR 42999, July 19, 2022). Based on these 
surveys, there is a possibility that the closure could affect the 
broader contribution of the GOM to future U.S. oil and gas activity. 
Given the relatively low level of take predicted to occur for Rice's 
whales in context of the de facto protection afforded through the 
circumscribed scope of the rule (i.e., the rule does not cover the bulk 
of Rice's whale core habitat, where whales are generally anticipated to 
occur, and no survey activity is expected to occur in the eastern GOM), 
NMFS has preliminarily determined that no additional mitigation is 
necessary or appropriate in order to effect the least practicable 
adverse impact on the species.
    NMFS has reevaluated the suite of mitigation measures required 
through the 2021 final regulations and considered other measures in 
light of the new information considered in this proposed rule. Based on 
our evaluation of these measures, we have preliminarily affirmed that 
the required mitigation measures contained in the current regulations 
provide the means of effecting the least practicable adverse impact on 
marine mammal species or stocks and their habitat, paying particular 
attention to rookeries, mating grounds, and areas of similar 
significance.

Proposed Monitoring and Reporting

    In order to issue an LOA for an activity, section 101(a)(5)(A) of 
the MMPA states that NMFS must set forth requirements pertaining to the 
monitoring and reporting of the authorized taking. NMFS' MMPA 
implementing regulations further describe the information that an 
applicant should provide when requesting an authorization (50 CFR 
216.104(a)(13)), including the means of accomplishing the necessary 
monitoring and reporting that will result in increased knowledge of the 
species and the level of taking or impacts on populations of marine 
mammals. Effective reporting is critical both to compliance as well as 
ensuring that the most value is obtained from the required monitoring.
    We do not propose changes to the current LOA reporting 
requirements, which have been sufficient to date. Accordingly, the 
monitoring and

[[Page 938]]

reporting requirements for this proposed rule remain identical to the 
2021 final rule and ITR, and we refer readers back to that document (86 
FR 5322, January 19, 2021) for the discussion.

Negligible Impact Analysis and Determinations

    NMFS has defined negligible impact 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 (50 CFR 216.103). A 
negligible impact finding is based on the lack of likely adverse 
effects on annual rates of recruitment or survival (i.e., population-
level effects). An estimate of the number of takes alone is not enough 
information on which to base a negligible impact determination. In 
addition to considering estimates of the number of marine mammals that 
might be ``taken'' by mortality, serious injury, and Level A or Level B 
harassment, we consider other factors, such as the type of take, the 
likely nature of any behavioral responses (e.g., intensity, duration), 
the context of any such responses (e.g., critical reproductive time or 
location, migration), as well as effects on habitat, and the likely 
effectiveness of mitigation. We also assess the number, intensity, and 
context of estimated takes by evaluating this information relative to 
population status. Consistent with the 1989 preamble for NMFS' 
implementing regulations (54 FR 40338, September 29, 1989), the impacts 
from other past and ongoing anthropogenic activities are incorporated 
into these analyses via their impacts on the baseline (e.g., as 
reflected in the regulatory status of the species, population size and 
growth rate where known, ongoing sources of human-caused mortality).
    For each potential activity-related stressor, NMFS considers the 
potential effects to marine mammals and the likely significance of 
those effects to the species or stock as a whole. Potential risk due to 
vessel collision and related mitigation measures, as well as potential 
risk due to entanglement and contaminant spills, was addressed in the 
Proposed Mitigation and Potential Effects of the Specified Activity on 
Marine Mammals sections of the 2018 and 2021 notices of proposed and 
final rulemaking and are not discussed further, as there are minimal 
risks expected from these potential stressors.
    The ``specified activity'' for this proposed rule continues to be a 
broad program of geophysical survey activity that could occur at any 
time of year in U.S. waters of the GOM, within the same specified 
geographical region as the 2021 final rule (i.e., updated from the 2018 
proposed rule to exclude the former GOMESA leasing moratorium area) and 
for the same 5-year period. The acoustic exposure modeling used for the 
2021 rulemaking and for this proposed rule provides marine mammal noise 
exposure estimates based on BOEM-provided projections of future survey 
effort and best available modeling of sound propagation, animal 
distribution, and animal movement. This provides a conservative but 
reasonable best estimate of potential acute noise exposure events that 
may result from the described suite of activities.
    In recognition of the broad geographic and temporal scale of this 
activity, in support of the issuance of the 2021 rule, we applied an 
explicit, systematic risk assessment framework (discussed in detail in 
the 2018 notice of proposed rulemaking) to evaluate potential effects 
of aggregated discrete acoustic exposure events (i.e., proposed 
geophysical survey activities) on marine mammals. This risk assessment 
framework, which is one component of the overall negligible impact 
analysis, was described by Southall et al. (2017) (available online at: 
www.fisheries.noaa.gov/national/marine-mammal-protection/incidental-take-authorizations-oil-and-gas), and discussed in detail in the 2018 
notice of proposed rulemaking. That framework, which was subsequently 
refined in response to public comment and in consideration of the 
updated scope of the activity (as discussed in the notice of issuance 
of the 2021 final rule), has not changed and is not described in detail 
in this notice. Please review the 2018 proposed and 2021 final rule 
notices, as well as Southall et al. (2017), for further detail. This 
framework continues to represent the best available methodology for 
assessing relative risk, and we incorporate the framework and its 
results into this analysis.
    In summary, the systematic risk assessment framework uses the 
modeling results to put into biologically-relevant context the level of 
potential risk of injury and/or disturbance to marine mammals. The 
framework considers both the aggregation of acute effects and the broad 
temporal and spatial scales over which chronic effects may occur. 
Generally, this approach is a relativistic risk assessment that 
provides an interpretation of the exposure estimates within the context 
of key biological and population parameters (e.g., population size, 
life history factors, compensatory ability of the species, animal 
behavioral state, aversion), as well as other biological, 
environmental, and anthropogenic factors. This analysis was performed 
on a species-specific basis within each modeling zone (Figure 2), and 
the end result provides an indication of the biological significance of 
the evaluated exposure numbers for each affected marine mammal stock 
(i.e., yielding the severity of impact and vulnerability of stock/
population information), and forecasts the likelihood of any such 
impact. This result is expressed as relative impact ratings of overall 
risk that couple potential severity of effect on a stock and likely 
vulnerability of the population to the consequences of those effects, 
given biologically relevant information (e.g., compensatory ability).
    Spectral, temporal, and spatial overlaps between survey activities 
and animal distribution are the primary factors that drive the type, 
magnitude, and severity of potential effects on marine mammals, and 
these considerations are integrated into both the severity and 
vulnerability assessments. The framework utilizes a strategic approach 
to balance the weight of these considerations between the two 
assessments, specifying and clarifying where and how the interactions 
between potential disturbance and species within these dimensions are 
evaluated. Overall ratings are then considered in conjunction with the 
required mitigation (and any additional relevant contextual 
information) to ultimately inform our determinations. Elements of this 
approach are subjective and relative within the context of this program 
of projected actions and, overall, the analysis necessarily requires 
the application of professional judgment.
    As shown in Tables 5 and 6, estimated take numbers for most species 
have decreased relative to those evaluated in the notice of issuance 
for the 2021 final rule. We note that this includes the ``blackfish'' 
guild (consisting of the false killer whale, pygmy killer whale, melon-
headed whale, and killer whale), for which species-specific take 
information is not available. Both the annual maximum and 5-year total 
take numbers for the group have decreased relative to the sum of the 
previous species-specific values (annual maxima and 5-year totals) 
evaluated in the 2021 final rule.
    As elements of the risk assessment framework are dependent on 
information related to stock abundance, we have revisited the risk 
assessment methodology for all species, and present updated information 
below. Specifically, as discussed below, severity ratings are the 
product of

[[Page 939]]

comparison between estimated take numbers and modeled population 
abundance, on a zone-specific basis. As the zone-specific modeled 
population abundance values have been updated through new density 
modeling (Garrison et al., 2022), we revisit all severity ratings. The 
vulnerability assessment component is less directly dependent on 
population abundance information, but does incorporate certain species 
population information, including a trend rating and population size, 
as well as a factor related to species habitat use. With publication of 
new SARs information for all species, we revisit the former components 
of the vulnerability assessment, whereas the aforementioned updated 
density modeling effort provides new zone-specific abundance values 
that inform the assessment of habitat use in each zone (i.e., 
proportion of GOM-wide estimated population in each zone).
    Estimated take numbers increased (relative to the 2021 final rule) 
for only four species: Rice's whale, Fraser's dolphin, rough-toothed 
dolphin, and striped dolphin (though it should be noted that overall 
relative risk ratings remained static for Rice's whale and Fraser's 
dolphin). Whether estimated take numbers increased for each of the four 
species within the ``blackfish'' category is unknown under NMFS' 
proposed approach to estimating take numbers. However, overall relative 
risk ratings increased slightly for most species. Of the species for 
which evaluated take decreased, relative risk ratings remained static 
(or declined) for the sperm whale, beaked whales, bottlenose dolphin, 
and spinner dolphin. No new information is available for these four 
taxa that would suggest that the existing negligible impact analyses 
should be revisited. Therefore, we rely on the existing negligible 
impact analyses for the sperm whale, all beaked whale species, 
bottlenose dolphin, and spinner dolphin. Please see the notice of 
issuance for the current rule (86 FR 5322, January 19, 2021) for 
analysis related to these species, which we incorporate by reference to 
this proposed rule. We revisit here the negligible impact analyses for 
those species for which evaluated take numbers increased and/or for 
which the assessed relative risk rating increased.
    The risk assessment framework comprehensively considers the 
aggregate impacts to marine mammal populations from the specified 
activities in the context of both the severity of the impacts and the 
vulnerability of the affected species. However, it does not consider 
the effects of the mitigation required through these regulations in 
identifying risk ratings for the affected species. In addition, while 
the risk assessment framework comprehensively considers the spatial and 
temporal overlay of the activities and the marine mammals in the GOM, 
as well as the number of predicted takes, there are details about the 
nature of any ``take'' anticipated to result from these activities that 
were not considered directly in the framework analysis that warrant 
explicit consideration in the negligible impact determination. 
Accordingly, following the description of the framework analysis 
presented below, NMFS highlights a few factors regarding the nature of 
the predicted ``takes'' and then brings together the results of 
implementation of the framework, these additional factors, and the 
anticipated effects of the mitigation to summarize the negligible 
impact analysis for each of the species considered here. The risk 
assessment analysis below is performed for 2 representative years, with 
Year 1 representing a relatively high-effort scenario and Year 4 
representing a moderate-effort scenario. Please see Table 2 for details 
regarding BOEM's level of effort projections.

Severity of Effect

    As described above in Estimated Take, a significant model 
assumption was that populations of animals were reset for each 24-hr 
period. Exposure estimates for the 24-hr period were then aggregated 
across all assumed survey days as completely independent events, 
assuming populations turn over completely within each large zone on a 
daily basis. In order to evaluate modeled daily exposures and determine 
more realistic exposure probabilities for individuals across multiple 
days, we used information on species-typical movement behavior to 
determine a species-typical offset of modeled daily exposures, 
summarized under Estimated Take (and discussed in further detail in the 
2021 notice of issuance for the final rule). Given that many of the 
evaluated survey activities occur for 30-day or longer periods, 
particularly some of the larger surveys for which the majority of the 
modeled exposures occur, using such a scaling process is appropriate in 
order to evaluate the likely severity of the predicted exposures and to 
estimate take for the purposes of LOA applications and predicting the 
number of individual marine mammals taken during the course of a single 
survey (although, for surveys significantly longer than 30 days, the 
take numbers with this scaling applied would still be expected to 
overestimate the number of individuals, given the greater degree of 
repeat exposures that would be expected the longer the survey goes on). 
This output was used in a severity assessment. This approach is also 
discussed in more detail in the Southall et al. (2017) report.
    The scaled Level B harassment takes were then rated through a 
population-dependent binning system, used to evaluate risk associated 
with behavioral disruption across species--a simple, logical means of 
evaluating relative risk across species and areas. See the notice of 
issuance for the 2021 final rule for more detail regarding the 
definition of relative risk ratings. Results of the reassessed severity 
ratings are shown in Table 10.
    Level A harassment (including PTS) is not expected to occur for any 
of the species evaluated here, with the exception of Kogia spp. 
Estimated takes by Level A harassment for Kogia spp., which are 
discussed in further detail below, declined relative to what was 
evaluated in the 2021 final rule. See Tables 5 and 6.

                                          Table 10--Severity Assessment
----------------------------------------------------------------------------------------------------------------
                                Zone 1 \1\    Zone 2      Zone 3    Zone 4 \1\    Zone 5      Zone 6     Zone 7
            Species            ---------------------------------------------------------------------------------
                                  H     M     H     M     H     M     H     M     H     M     H     M    H    M
----------------------------------------------------------------------------------------------------------------
Rice's whale..................  VL    VL    VL    VL    VL    VL    VL    VL    VL    VL    VL    VL    n/a  n/a
Sperm whale...................  n/a   n/a   n/a   n/a   n/a   n/a   VL    VL    H     H     M     L     L    L
Kogia spp.....................  n/a   n/a   n/a   n/a   n/a   n/a   VL    VL    H     M     M     L     L    VL
Beaked whales.................  n/a   n/a   n/a   n/a   n/a   n/a   VL    VL    VH    VH    VL    VL    VL   VL
Rough-toothed dolphin.........  VL    VL    L     M     VL    VL    VL    VL    H     H     M     L     L    L
Bottlenose dolphin............  VL    VL    L     M     VL    VL    VL    VL    M     M     L     VL    n/a  n/a
Clymene dolphin...............  n/a   n/a   n/a   n/a   n/a   n/a   VL    VL    H     H     M     L     L    VL
Atlantic spotted dolphin......  VL    VL    M     H     VL    VL    VL    VL    H     M     M     L     n/a  n/a

[[Page 940]]

 
Pantropical spotted dolphin...  n/a   n/a   n/a   n/a   n/a   n/a   VL    VL    H     H     M     L     L    VL
Spinner dolphin...............  n/a   n/a   n/a   n/a   n/a   n/a   VL    VL    H     H     n/a   n/a   VL   VL
Striped dolphin...............  n/a   n/a   n/a   n/a   n/a   n/a   VL    VL    H     H     M     L     L    VL
Fraser's dolphin..............  VL    VL    VL    VL    VL    VL    VL    VL    H     H     M     L     L    L
Risso's dolphin...............  n/a   n/a   VL    VL    n/a   n/a   VL    VL    H     M     M     L     L    VL
Short-finned pilot whale......  n/a   n/a   VL    VL    VL    VL    VL    VL    H     M     M     L     VL   VL
Blackfish.....................  n/a   n/a   n/a   n/a   n/a   n/a   VL    VL    H     H     M     L     L    L
----------------------------------------------------------------------------------------------------------------
H = Year 1 (representative high effort scenario); M = Year 4 (representative moderate effort scenario).
n/a = less than 0.05 percent of GOM-wide population predicted in zone.
VL = very low; L = low; M = moderate; H = high; VH = very high.
\1\ No activity would occur in Zone 1, and no activity is projected in Zone 4 under the high effort scenario.
  With no activity in a zone, severity is assumed to be very low.

Vulnerability of Affected Population

    Vulnerability rating seeks to evaluate the relative risk of a 
predicted effect given species-typical and population-specific 
parameters (e.g., species-specific life history, population factors) 
and other relevant interacting factors (e.g., human or other 
environmental stressors). The assessment includes consideration of four 
categories within two overarching risk factors (species-specific 
biological and environmental risk factors). These values were selected 
to capture key aspects of the importance of spatial (geographic), 
spectral (frequency content of noise in relation to species-typical 
hearing and sound communications), and temporal relationships between 
sound and receivers. Explicit numerical criteria for identifying scores 
were specified where possible, but in some cases qualitative judgments 
based on a reasonable interpretation of given aspects of the proposed 
activity and how it relates to the species in question and the 
environment within the specified area were required. Factors considered 
in the vulnerability assessment were detailed in Southall et al. (2017) 
and discussed in further detail in the notice of issuance for the 2021 
final rule. Please see that notice for further detail regarding these 
aspects of the framework and for definitions of vulnerability ratings. 
Note that the effects of the DWH oil spill are accounted for through a 
non-noise chronic anthropogenic risk factor, while the effects to 
acoustic habitat and on individual animal behavior via masking are 
accounted for through the masking and chronic anthropogenic noise risk 
factors. The results of reassessed species-specific vulnerability 
scoring are shown in Table 11. Note that, as there are certain species-
specific elements of the vulnerability assessment, we evaluated and 
present results for each of the four species contained within the 
``blackfish'' group. For purposes of evaluating relative risk, we 
assume that the greatest vulnerability (assessed for melon-headed 
whale) applies to the blackfish group as a whole.

                   Table 11--Vulnerability Assessment
------------------------------------------------------------------------
                                                  Zone
            Species            -----------------------------------------
                                  1     2     3     4     5     6     7
------------------------------------------------------------------------
Rice's whale..................  H     H     M     H     H     H     n/a
Sperm whale...................  n/a   n/a   n/a   M     H     M     M
Kogia spp.....................  n/a   n/a   n/a   L     L     L     L
Beaked whale..................  n/a   n/a   n/a   L     L     L     L
Rough-toothed dolphin.........  L     L     L     L     L     L     L
Bottlenose dolphin............  L     L     L     VL    L     VL    n/a
Clymene dolphin...............  n/a   n/a   n/a   L     L     L     L
Atlantic spotted dolphin......  M     M     L     L     L     L     n/a
Pantropical spotted dolphin...  n/a   n/a   n/a   L     L     L     L
Spinner dolphin...............  n/a   n/a   n/a   L     L     n/a   L
Striped dolphin...............  n/a   n/a   n/a   L     L     L     L
Fraser's dolphin..............  L     L     VL    L     L     L     L
Risso's dolphin...............  n/a   L     n/a   M     M     M     L
Melon-headed whale............  n/a   n/a   n/a   L     M     L     L
Pygmy killer whale............  n/a   n/a   n/a   L     L     L     L
False killer whale............  n/a   n/a   n/a   L     L     L     L
Killer whale..................  n/a   n/a   n/a   L     L     L     L
Short-finned pilot whale......  n/a   M     L     M     M     M     L
------------------------------------------------------------------------
n/a = less than 0.05% of GOM-wide population predicted in zone.
VL = very low; L = low; M = moderate; H = high; VH = very high.

Risk

    In the final step of the framework, severity and vulnerability 
ratings are integrated to provide relative impact ratings of overall 
risk. Severity and vulnerability assessments each produce a numerical 
rating (1-5) corresponding with the qualitative rating (i.e., very low, 
low, moderate, high, very high). A matrix is then used to integrate 
these two scores to provide an overall risk assessment. The matrix is 
shown in Table 2 of Southall et al. (2017).
    Table 12 provides relative impact ratings by zone, and Table 13 
provides GOM-wide relative impact ratings, for overall risk associated 
with predicted takes, for representative high and moderate effort 
scenarios.

[[Page 941]]



                         Table 12--Overall Evaluated Risk by Zone and Activity Scenario
----------------------------------------------------------------------------------------------------------------
                                Zone 1 \1\    Zone 2      Zone 3    Zone 4 \1\    Zone 5      Zone 6     Zone 7
            Species            ---------------------------------------------------------------------------------
                                  H     M     H     M     H     M     H     M     H     M     H     M    H    M
----------------------------------------------------------------------------------------------------------------
Rice's whale..................  L     L     L     L     L     L     L     L     L     L     L     L     n/a  n/a
Sperm whale...................  n/a   n/a   n/a   n/a   n/a   n/a   L     L     VH    VH    M     L     L    L
Kogia spp.....................  n/a   n/a   n/a   n/a   n/a   n/a   VL    VL    H     M     M     L     L    VL
Beaked whale..................  n/a   n/a   n/a   n/a   n/a   n/a   VL    VL    VH    VH    VL    VL    VL   VL
Rough-toothed dolphin.........  VL    VL    L     M     VL    VL    VL    VL    H     H     M     L     L    L
Bottlenose dolphin............  VL    VL    L     M     VL    VL    VL    VL    H     M     M     VL    n/a  n/a
Clymene dolphin...............  n/a   n/a   n/a   n/a   n/a   n/a   VL    VL    H     H     M     L     L    VL
Atlantic spotted dolphin......  L     L     M     H     VL    VL    VL    VL    H     M     M     L     n/a  n/a
Pantropical spotted dolphin...  n/a   n/a   n/a   n/a   n/a   n/a   VL    VL    H     H     M     L     L    VL
Spinner dolphin...............  n/a   n/a   n/a   n/a   n/a   n/a   VL    VL    H     H     n/a   n/a   VL   VL
Striped dolphin...............  n/a   n/a   n/a   n/a   n/a   n/a   VL    VL    H     H     M     L     L    L
Fraser's dolphin..............  VL    VL    VL    VL    VL    VL    VL    VL    H     H     M     L     L    L
Risso's dolphin...............  n/a   n/a   VL    VL    n/a   n/a   L     L     H     H     M     L     L    VL
Short-finned pilot whale......  n/a   n/a   L     L     VL    VL    L     L     H     M     M     L     VL   VL
Blackfish.....................  n/a   n/a   n/a   n/a   n/a   n/a   VL    VL    H     H     M     L     L    L
----------------------------------------------------------------------------------------------------------------
H = Year 1 (representative high effort scenario); M = Year 4 (representative moderate effort scenario).
n/a = less than 0.05 percent of GOM-wide population predicted in zone.
VL = very low; L = low; M = moderate; H = high; VH = very high.
\1\ No activity would occur in Zone 1, and no activity is projected in Zone 4 under the high effort scenario.
  With no activity in a zone, severity is assumed to be very low.


  Table 13--Overall Evaluated Risk by Projected Activity Scenario, GOM-
                                  Wide
------------------------------------------------------------------------
                                      High effort       Moderate effort
             Species               scenario (year 1)   scenario (year 4)
------------------------------------------------------------------------
Rice's whale....................  Low (0)...........  Low (0).
Sperm whale.....................  Low/Moderate \1\    Low (0).
                                   (0).
Kogia spp.......................  Low/Moderate \1\    Very Low/Low \1\
                                   (+0.5).             (+0.5).
Beaked whales...................  Very Low (-2.5)...  Very Low (-1.5).
Rough-toothed dolphin...........  Low (+1)..........  Low (+1).
Bottlenose dolphin (shelf/        Very low (0)......  Very low (0).
 coastal).
Bottlenose dolphin (oceanic)....  Very low (0)......  Very low (0).
Clymene dolphin.................  Low/Moderate \1\    Very Low/Low \1\
                                   (+0.5).             (0).
Atlantic spotted dolphin........  Low/Moderate \1\    Low (0).
                                   (+0.5).
Pantropical spotted dolphin.....  Low/Moderate \1\    Very Low/Low \1\
                                   (+0.5).             (+0.5).
Spinner dolphin.................  Very low (0)......  Very low (0).
Striped dolphin.................  Low/Moderate \1\    Low (+1).
                                   (+0.5).
Fraser's dolphin................  Very low (0)......  Very low (0).
Risso's dolphin.................  Low (+1)..........  Low (+1).
Short-finned pilot whale........  Low (0)...........  Low (+0.5).
Blackfish.......................  Low/Moderate        Low (+1).
                                   (+1.5).
------------------------------------------------------------------------
\1\ For these ratings, the median value across zones for the scenario
  fell between two ratings.
\2\ In the 2021 final rule, the four ``blackfish'' species were each
  independently evaluated as having ``very low'' relative risk.

    In order to characterize the relative risk for each species across 
their entire range in the GOM, we used the median of the seven zone-
specific risk ratings for each activity scenario (high and moderate 
effort), not counting those in which less than 0.05 percent of the GOM-
wide abundance occurred (``n/a'' in Table 12), to describe a GOM-wide 
risk rating for each of the representative activity scenarios (Table 
13).
    As noted above, for sperm whale, beaked whales, bottlenose dolphin, 
and spinner dolphin, estimated take numbers decreased and relative risk 
ratings remained static (or decreased) compared with the 2021 final 
rule. Therefore, we rely on the analysis provided in the notice of 
issuance for the 2021 final rule for those species, which are not 
discussed further here.
    Overall, the results of the risk assessment show that (as 
expected), risk is highly correlated with effort and density. Areas 
where little or no survey activity is predicted to occur or areas 
within which few or no animals of a particular species are believed to 
occur generally have very low or no potential risk of negatively 
affecting marine mammals, as seen across activity scenarios in Zones 1-
4 (no activity will occur in Zone 1, which was entirely removed from 
scope of the rule, and less than 2 percent of Zone 4 remains within 
scope of the rule). Fewer species are expected to be present in Zones 
1-3, where only bottlenose and Atlantic spotted dolphins occur in 
meaningful numbers. (Rice's whale core habitat largely overlaps Zone 1, 
which is not within scope of this rule.) Areas with consistently high 
levels of effort (Zones 5-7) are generally predicted to have higher 
overall evaluated risk across all species. In Zone 7, animals are 
expected to be subject to less other chronic noise and non-noise 
stressors, which is reflected in the vulnerability scoring for that 
zone. Therefore, despite consistently high levels of projected effort, 
overall rankings for that zone are lower than for Zones 5 and 6.
    A ``high'' level of relative risk due to behavioral disturbance was 
identified in Zone 5 under both scenarios for most of the species 
evaluated further in the following (excepting Rice's whale (both 
scenarios) as well as Kogia spp., Atlantic spotted dolphin, and short-
finned pilot whale (moderate effort scenario only)). ``High'' relative 
risk was not identified under either scenario in any other zone for any 
species (and ``very high'' relative risk was not identified under 
either

[[Page 942]]

scenario in any zone for any of the species evaluated further in the 
following). Overall, the greatest relative risk across species is 
generally seen in Zone 5 (both scenarios) and in Zone 6 (under the high 
effort scenario).
    Changes to relative risk ratings may be seen by comparing Table 13 
above with Table 15 from the 2021 final rule, and changes (in numerical 
terms) are indicated in parentheses for each scenario. All increases to 
assessed relative risk represent minor changes, i.e., if considered as 
a numerical scale (with ``very low'' = 1 and ``very high'' = 5), with 
one exception, there was no risk rating increase greater than one 
point. As noted above, despite increases in estimated take numbers, 
relative risk ratings for Rice's whale and Fraser's dolphin remained 
static. In the 2021 final rule, all four species comprising the 
``blackfish'' group were individually assessed as having ``very low'' 
relative risk under both scenarios. In this analysis, the blackfish as 
a group are assessed as having relative risk between ``low'' and 
``moderate'' under the high effort scenario (representing the lone 
example of a 1.5 point increase) and ``low'' under the moderate effort 
scenario.
    Although the scores generated by the risk assessment framework and 
further aggregated across zones (as described above) are species-
specific, additional stock-specific information is also considered in 
our analysis, where appropriate, as indicated in the Description of 
Marine Mammals in the Area of the Specified Activity, Potential Effects 
of the Specified Activity on Marine Mammals and Their Habitat, and 
Proposed Mitigation sections of the 2018 notice of proposed rulemaking, 
2021 notice of issuance of the final rule, and this proposed action.

Duration of Level B Harassment Exposures

    In order to more fully place the predicted amount of take into 
meaningful context, it is useful to understand the duration of exposure 
at or above a given level of received sound, as well as the likely 
number of repeated exposures across days. While a momentary exposure 
above the criteria for Level B harassment counts as an instance of 
take, that accounting does not make any distinction between fleeting 
exposures and more severe encounters in which an animal may be exposed 
to that received level of sound for a longer period of time. Yet, this 
information is meaningful to an understanding of the likely severity of 
the exposure, which is relevant to the negligible impact evaluation and 
not directly incorporated into the risk assessment framework described 
above. Each animat modeled has a record or time history of received 
levels of sound over the course of the modeled 24-hr period. For 
example, for the four ``blackfish'' species exposed to noise from 3D 
WAZ surveys, the 50th percentile of the cumulative distribution 
function indicates that the time spent exposed to levels of sound above 
160 dB rms SPL (i.e., the 50 percent midpoint for Level B harassment) 
would range from only 1.4 to 3.3 minutes--a minimal amount of exposure 
carrying little potential for significant disruption of behavioral 
activity. We provide summary information for the species evaluated here 
regarding the total average time in a 24-hr period that an animal would 
spend with received levels above 160 dB and between 140 and 160 dB in 
Table 14. This information considered is unchanged from the 2021 notice 
of issuance for the final rule.
    Additionally, as we discussed in the Estimated Take section of the 
2018 notice of proposed rulemaking for Test Scenario 1 (and summarized 
above), by comparing exposure estimates generated by multiplying 24-hr 
exposure estimates by the total number of survey days versus modeling 
for a full 30-day survey duration for six representative species, we 
were able to refine the exposure estimates to better reflect the number 
of individuals exposed above threshold within a single survey. Using 
this same comparison and scalar ratios described above, we are able to 
predict an average number of days each of the representative species 
modeled in the test scenario were exposed above the Level B harassment 
thresholds within a single survey. As with the duration of exposures 
discussed above, the number of repeated exposures is important to an 
understanding of the severity of effects. For example, the ratio for 
dolphins indicates that the 30-day modeling showed that approximately 
29 percent as many individual dolphins (compared to the results 
produced by multiplying average 24-hr exposure results by the 30-day 
survey duration) could be expected to be exposed above harassment 
thresholds. However, the approach of scaling up the 24-hour exposure 
estimates appropriately reflects the instances of exposure above 
threshold (which cannot be more than 1 in 24 hours), so the inverse of 
the scalar ratio suggests the average number of days in the 30-day 
modeling period that dolphins are exposed above threshold is 
approximately 3.5. It is important to remember that this is an average 
and that it is more likely some individuals would be exposed on fewer 
days and some on more. Table 14 reflects the average days exposed above 
threshold for the indicated species having applied the scalar ratios 
described previously.

     Table 14--Time in Minutes (Per Day) Spent Above Thresholds (50th Percentile) and Average Number of Days Individuals Taken During 30-Day Survey
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                           Survey type and time (min/day) above    Survey type and time (min/day) above   Average number
                                                                   160 dB rms (50% take)                   140 dB rms (10% take)              of days
                         Species                         --------------------------------------------------------------------------------    ``taken''
                                                                                                                                           during 30-day
                                                             2D      3D NAZ    3D WAZ     Coil       2D      3D NAZ    3D WAZ     Coil        survey
--------------------------------------------------------------------------------------------------------------------------------------------------------
Rice's whale............................................       7.6      18.2       6.8      21.4      61.7     163.5      55.4     401.1             5.3
Sperm whale.............................................       5.2      10.3       4.0      20.7      12.0      31.8      10.7      25.2             2.4
Kogia spp...............................................       3.2       7.9       2.8      15.3       7.6      19.0       6.7      13.9             3.1
Beaked whale............................................       6.0      12.4       4.4      24.0      16.2      39.7      14.1      31.1             9.9
Rough-toothed dolphin...................................       3.0       6.3       2.5      11.4      11.2      27.6      10.2      20.9             3.5
Bottlenose dolphin......................................       4.5      11.7       4.0      16.8      22.0      54.6      19.7      53.2             3.5
Clymene dolphin.........................................       1.8       3.9       1.6       8.7       8.0      21.1       7.2      20.4             3.5
Atlantic spotted dolphin................................       7.0      16.0       6.5      25.7      23.4      58.1      20.9      49.3             3.5
Pantropical spotted dolphin.............................       1.8       4.1       1.6       8.7       8.1      21.0       7.1      22.2             3.5
Spinner dolphin.........................................       3.2       8.5       2.7      16.4      12.4      31.0      10.8      22.8             3.5
Striped dolphin.........................................       1.8       4.0       1.6       8.5       8.0      21.0       7.2      21.3             3.5
Fraser's dolphin........................................       2.8       6.4       2.4      13.8       9.4      24.2       8.4      24.0             3.5
Risso's dolphin.........................................       3.4       8.4       2.9      15.3      13.8      37.7      12.2      31.5             3.5
Melon-headed whale......................................       2.6       5.9       2.2      13.1       9.3      24.2       8.3      24.0             3.4

[[Page 943]]

 
Pygmy killer whale......................................       1.8       3.6       1.4       7.1       7.3      18.5       6.6      17.3             3.4
False killer whale......................................       2.4       4.9       1.9       9.3       8.8      22.0       8.0      17.8             3.4
Killer whale............................................       2.7       6.1       3.3      12.0      16.8      46.1      14.9      73.6             3.4
Short-finned pilot whale................................       3.3       8.1       2.9      17.5      10.9      27.4       9.8      20.8             3.4
--------------------------------------------------------------------------------------------------------------------------------------------------------

Loss of Hearing Sensitivity

    In general, NMFS expects that noise-induced hearing loss as a 
result of airgun survey activity, whether temporary (temporary 
threshold shift, equivalent to Level B harassment) or permanent (PTS, 
equivalent to Level A harassment), is only possible for low-frequency 
and high-frequency cetaceans. The best available scientific information 
indicates that low-frequency cetacean species (i.e., mysticete whales, 
including the Rice's whale) have heightened sensitivity to frequencies 
in the range output by airguns, as shown by their auditory weighting 
function, whereas high-frequency cetacean species (including Kogia 
spp.) have heightened sensitivity to noise in general (as shown by 
their lower threshold for the onset of PTS) (NMFS, 2018). However, no 
instances of Level A harassment are predicted to occur for Rice's 
whales, and none would be authorized under this rule.
    Level A harassment is predicted to occur for Kogia spp. (as 
indicated in Table 6). However, the degree of injury (hearing 
impairment) is expected to be mild. If permanent hearing impairment 
occurs, it is most likely that the affected animal would lose a few dB 
in its hearing sensitivity, which in most cases would not be expected 
to affect its ability to survive and reproduce. Hearing impairment that 
occurs for these individual animals would be limited to at or slightly 
above the dominant frequency of the noise sources. In particular, the 
predicted PTS resulting from airgun exposure is not likely to affect 
their echolocation performance or communication, as Kogia spp. likely 
produce acoustic signals at frequencies above 100 kHz (Merkens et al., 
2018), well above the frequency range of airgun noise. Further, modeled 
exceedance of Level A harassment criteria typically resulted from being 
near an individual source once, rather than accumulating energy from 
multiple sources. Overall, the modeling indicated that exceeding the 
SEL threshold is a rare event, and having four vessels close to each 
other (350 m between tracks) did not cause appreciable accumulation of 
energy at the ranges relevant for injury exposures. Accumulation of 
energy from independent surveys is expected to be negligible. This is 
relevant for Kogia spp. because based on their expected sensitivity, we 
expect that aversion may play a stronger role in avoiding exposures 
above the peak pressure PTS threshold than for which we have accounted.
    However, some subset of the individual marine mammals predicted to 
be taken by Level B harassment may incur some TTS. For Rice's whales, 
TTS may occur at frequencies important for communication. However, any 
TTS incurred would be expected to be of a relatively small degree and 
short duration. This is due to the low likelihood of sound source 
approaches of the proximity or duration necessary to cause more severe 
TTS, given the fact that both sound source and marine mammals are 
continuously moving, the anticipated effectiveness of shutdowns, and 
general avoidance by marine mammals of louder sources.
    For these reasons, and in conjunction with the required mitigation, 
NMFS does not believe that Level A harassment (here, PTS) or Level B 
harassment in the form of TTS will play a meaningful role in the 
overall degree of impact experienced by marine mammal populations as a 
result of the projected survey activity. Further, the impacts of any 
TTS incurred are addressed through the broader analysis of Level B 
harassment.

Impacts to Habitat

    Potential impacts to marine mammal habitat, including to marine 
mammal prey, were discussed in detail in the 2018 notice of proposed 
rulemaking as well as in the 2021 notice of issuance for the final 
rule, including in responses to comments concerning these issues. There 
is no new information that changes that assessment, and we rely on the 
assessment provided in those documents and reiterated below.
    Regarding impacts to prey species such as fish and invertebrates, 
NMFS' review of the available information leads to a conclusion that 
the most likely impact of survey activity would be temporary avoidance 
of an area, with a rapid return to pre-survey distribution and 
behavior, and minimal impacts to recruitment or survival anticipated. 
Therefore, the specified activities are not likely to have more than 
short-term adverse effects on any prey habitat or populations of prey 
species. Further, any impacts to prey species are not expected to 
result in significant or long-term consequences for individual marine 
mammals, or to contribute to adverse impacts on their populations.
    Regarding potential impacts to acoustic habitat, NMFS provided a 
detailed analysis of potential cumulative and chronic effects to marine 
mammals (found in the Cumulative and Chronic Effects report, available 
online at www.fisheries.noaa.gov/action/incidental-take-authorization-oil-and-gas-industry-geophysical-survey-activity-gulf-mexico). That 
analysis focused on potential effects to sperm whales and Rice's 
whales. The analysis performed for sperm whales (which provides a 
useful proxy for other mid- and high-frequency cetaceans evaluated 
here) shows that the survey activities do not significantly contribute 
to the soundscape in the frequency band relevant for their lower-
frequency slow-clicks and that there will be no significant change in 
communication space for sperm whales. Similar conclusions may be 
assumed for other mid- and high-frequency cetacean species.
    Implications for acoustic masking and reduced communication space 
resulting from noise produced by airgun surveys in the GOM are expected 
to be particularly heightened for animals that actively produce low-
frequency sounds or whose hearing is attuned to lower frequencies 
(i.e., Rice's whales). The strength of the communication space approach 
used here is that it evaluates potential contractions in the 
availability

[[Page 944]]

of a signal of documented importance to a population of animals of key 
management interest in the region. In this case, losses of 
communication space for Rice's whales were estimated to be higher in 
eastern and central GOM canyons and shelf break areas. In contrast, 
relative maintenance of listening area and communication space was seen 
within the Rice's whale core habitat area in the eastern GOM. The 
result was heavily influenced by the projected lack of survey activity 
in that region, which underscores the importance of maintaining this 
important habitat for the Rice's whale. Following BOEM's 2020 update to 
the scope of the specified activity, no survey activity will occur 
under this rule within the majority of Rice's whale core habitat (95 
percent of the updated core habitat area lies outside the geographic 
scope of this rule, including all confirmed Rice's whale sightings 
within the area) or within the broader eastern GOM. See Figures 3-4. In 
areas where larger amounts of survey activity were projected, 
significant loss of low-frequency listening area and communication 
space for Rice's whale calls was estimated. However, these are areas 
where Rice's whales are unlikely to occur (i.e., deeper waters of the 
central and western GOM).

Species-Specific Negligible Impact Analysis Summaries

    In this section, for the species evaluated herein (i.e., all but 
sperm whale, beaked whales, bottlenose dolphin, and spinner dolphin, 
for which, as described previously, we incorporate by reference the 
analysis conducted in the 2018 rule), we consider the relative impact 
ratings described above in conjunction with the required mitigation and 
other relevant contextual information in order to produce a final 
assessment of impact to the stock or species, i.e., the negligible 
impact determinations. The effects of the DWH oil spill are accounted 
for through the vulnerability scoring (Table 11).
    Although the Rice's whale core habitat area is not the subject of 
restrictions on survey activity, as the scope of the specified activity 
does not functionally include the area (95 percent of the updated core 
habitat area remains out of scope of the rule, with all confirmed 
sightings of Rice's whales within the core habitat area occurring in 
the portion outside the scope of this rule; see Figure 4), the 
beneficial effect for animals in the area described in the 2018 
proposed rule remains the same. The absence of survey activity in the 
eastern GOM (see Figure 2) benefits GOM marine mammals by reducing the 
portion of a stock likely exposed to survey noise and avoiding impacts 
to certain species in areas of importance for them. Habitat areas of 
importance in the eastern GOM are discussed in detail in the Proposed 
Mitigation section of the 2018 notice of proposed rulemaking.

Rice's Whale

    The risk assessment analysis, which evaluated the relative 
significance of the aggregated impacts of the survey activities across 
seven GOM zones in the context of the vulnerability of each species, 
concluded that the GOM-wide risk ratings for Rice's whales are low, 
regardless of activity scenario. We note that, although the evaluated 
severity of take for Rice's whales is very low in all zones where take 
could occur, vulnerability for the species is assessed as high in five 
of the six zones where the species occurs (vulnerability is assessed as 
moderate in Zone 3, where less than 1 percent of GOM-wide abundance is 
predicted to occur). When integrated through the risk framework 
described above, overall risk for the species is therefore assessed as 
low for both the high and moderate effort scenarios. The evaluated risk 
rating is the same as what was considered in the 2021 notice of 
issuance of the final rule, despite increased take numbers (see Tables 
5-6). In the context of what remain relatively low predicted take 
numbers, the relative risk ratings for the species remain driven by the 
assessed vulnerability.
    We further consider the likely severity of any predicted behavioral 
disruption of Rice's whales in the context of the likely duration of 
exposure above Level B harassment thresholds. Specifically, the average 
modeled time per day spent at received levels above 160 dB rms (where 
50 percent of the exposed population is considered taken) ranges from 
6.8-21.4 minutes for deep penetration survey types. The average time 
spent exposed to received levels between 140 and 160 dB rms (where 10 
percent of the exposed population is considered taken) ranges from 55-
164 minutes for 2D, 3D NAZ, and 3D WAZ surveys, and 401 minutes for 
coil surveys (which comprise approximately 10 percent of the total 
activity days).
    Importantly, no survey activity will occur within the eastern GOM 
pursuant to this rule. Although there is new evidence of Rice's whale 
occurrence outside the eastern GOM from passive acoustic detections 
(Soldevilla et al., 2022), all but one confirmed Rice's whale sighting 
are within the historically considered eastern GOM core area (see 
Figure 4). The nature of Rice's whale habitat use outside of the 
eastern GOM core area is poorly understood, including information about 
the number of individuals that may occur outside the eastern GOM. 
(Soldevilla et al. (2022) suggest that more than one individual was 
present on at least one occasion, as overlapping calls of different 
call subtypes were recorded in that instance, but also state that call 
production rates suggest that either multiple individuals are typically 
calling or that individual whales are producing calls at higher rates 
in the western GOM.)
    This new information does not affect the prior conclusion that the 
absence of survey activity in the eastern GOM is expected to benefit 
Rice's whales and their habitat by minimizing a range of potential 
effects of airgun noise, both acute and chronic, that could otherwise 
accrue to impact the reproduction or survival of individuals in this 
area, and that the absence of survey activity in the eastern GOM will 
minimize disturbance of the species in the place most important to them 
for critical behaviors such as foraging and socialization. The Roberts 
et al. (2016) density model indicated that the core habitat area 
evaluated in the 2018 proposed rule encompassed approximately 92 
percent of the predicted abundance of Rice's whales in the GOM. The 
updated Rice's whale density model (Garrison et al., 2022), which 
incorporates newer survey data, as well as winter survey data for the 
first time, indicates that the updated core habitat area contains 
approximately 57 percent of predicted Rice's whale abundance.\8\ As 
noted previously, intensive survey effort in the region has not 
resulted in any confirmed Rice's whale sightings outside the core 
habitat area (aside from a single anomalous sighting in the western 
GOM). Although it is possible that some surveys could occur within the 
small portion of the updated core habitat area within scope of the rule 
(approximately 5 percent; see Figures 3-4), or that some sound from 
airguns may still propagate into the Rice's whale core habitat area 
from surveys that may occur outside of the area, exposure of Rice's 
whales to sound

[[Page 945]]

levels that may be expected to result in Level B harassment will be 
eliminated or reduced for animals within the Rice's whale core area. 
(We note that, in NMFS' experience implementing the rule to date, no 
survey has occurred within the updated Rice's whale core habitat area, 
nor has any survey occurred at sufficiently close proximity to the core 
habitat area that sound reasonably expected to result in harassment 
would have entered.) The absence of survey activity in this area and 
significant reduction in associated exposure of Rice's whales to 
seismic airgun noise is expected to eliminate the likelihood of 
auditory injury of Rice's whales. Finally, the absence of survey 
activity in the eastern GOM will reduce chronic exposure of Rice's 
whales to higher levels of anthropogenic sound and the associated 
effects including masking, disruption of acoustic habitat, long-term 
changes in behavior such as vocalization, and stress.
---------------------------------------------------------------------------

    \8\ The percent of abundance predicted to occur in the eastern 
GOM has declined as a result of expanded density predictions into 
the western GOM. The Roberts et al. (2016) model included a 
bivariate smooth of XY, with the effect that predicted density was 
concentrated where sightings were reported (i.e., the eastern GOM; 
see Figure 4). The updated model does not include this and, 
importantly, is informed by the confirmed 2017 sighting of a Rice's 
whale in the western GOM. The result is an increase in predicted 
density within shelf break waters throughout the GOM that are within 
the depth ranges where Rice's whales have historically been observed 
within the eastern GOM.
---------------------------------------------------------------------------

    As described in the preceding Loss of Hearing Sensitivity section, 
we have analyzed the likely impacts of potential temporary hearing 
impairment and do not expect that they would result in impacts on 
reproduction or survival of any individuals. The extended shutdown zone 
for Rice's whales (1,500 m)--to be implemented in the unlikely event 
that a Rice's whale is encountered outside of the core habitat area--is 
expected to further minimize the severity of any hearing impairment 
incurred as well as reducing the likelihood of more severe behavioral 
responses. Similarly, application of this extended distance shutdown 
requirement when calves are present will minimize the potential for and 
degree of disturbance during this sensitive life stage.
    NMFS has corrected the take estimates in the 2021 final rule 
generated by BOEM's errors, which appear to have caused a particularly 
large reduction in estimated take for Rice's whale. As a result, and in 
consideration of updated density information and other factors, the 
estimated take numbers for Rice's whale are increased from those 
considered in the 2021 final rule (see Tables 5-6). Accordingly, NMFS 
has re-evaluated the relative risk rating for Rice's whale (Tables 12-
13), and considered other relevant information for the species. The 
risk ratings did not change from those assessed in the 2021 final rule, 
and new information considered herein does not affect the 
determinations previously made in that analysis.
    No mortality of Rice's whales is anticipated or authorized. It is 
possible that Rice's whale individuals, if encountered in areas not 
typically considered to be Rice's whale habitat, will be impacted 
briefly on one or more days during a year of activity by one type of 
survey or another and some subset of those exposures above thresholds 
may be of comparatively long duration within a day. However, the 
significant and critical protection afforded through the absence of 
survey activity in the core habitat area ensures that the impacts of 
the expected takes from these activities are not likely to adversely 
affect Rice's whales through impacts on annual rates of recruitment or 
survival. Kogia spp.
    The risk assessment analysis, which evaluated the relative 
significance of the aggregated impacts of the survey activities across 
seven GOM zones in the context of the vulnerability of each species, 
concluded that the GOM-wide risk ratings for Kogia spp. were between 
low and moderate (for the high effort scenario) and between very low 
and low (for the moderate effort scenario). Evaluated risk is slightly 
increased from the 2021 final rule, with modeled decreases in zone-
specific population abundance offsetting decreases in estimated take. 
We further consider the likely severity of any predicted behavioral 
disruption of Kogia spp. in the context of the likely duration of 
exposure above Level B harassment thresholds. Specifically, the average 
modeled time per day spent at received levels above 160 dB rms (where 
50 percent of the exposed population is considered taken) ranges from 
2.8-7.9 minutes for 2D, 3D NAZ, and 3D WAZ surveys and up to 15.3 
minutes for coil surveys (which comprise less than 10 percent of the 
total projected activity days), and the average time spent between 140 
and 160 dB rms (where 10 percent of the exposed population is 
considered taken) is 6.7-19 minutes.
    Odontocetes echolocate to find prey, and while there are many 
different strategies for hunting, one common pattern, especially for 
deeper diving species, is to conduct multiple repeated deep dives 
within a feeding bout, and multiple bouts within a day, to find and 
catch prey. While exposures of the short durations noted above could 
potentially interrupt a dive or cause an individual to relocate to 
feed, such a short-duration interruption would be unlikely to have 
significant impacts on an individual's energy budget and, further, for 
these species and this open-ocean area, there are no specific known 
reasons (i.e., these species range GOM-wide beyond the continental 
slope and there are no known biologically important areas) to expect 
that there would not be adequate alternate feeding areas relatively 
nearby, especially considering the anticipated absence of survey 
activity in the eastern GOM.
    As described above, no survey activity is expected within the 
eastern GOM. Importantly, the absence of survey activity in the area 
will reduce disturbance of Kogia spp. in places of importance to them 
for critical behaviors such as foraging and socialization and, overall, 
help to reduce impacts to the stocks as a whole.
    NMFS has analyzed the likely impacts of potential hearing 
impairment, including the estimated upper bounds of permanent threshold 
shift (Level A harassment) that could be authorized under the rule and 
do not expect that they would result in impacts on reproduction or 
survival of any individuals. As described in the previous section, the 
degree of injury for individuals would be expected to be mild, and the 
predicted PTS resulting from airgun exposure is not likely to affect 
echolocation performance or communication for Kogia spp. Additionally, 
the extended distance shutdown zone for Kogia spp. (1,500 m) is 
expected to further minimize the severity of any hearing impairment 
incurred and also to further reduce the likelihood of, and minimize the 
severity of, more severe behavioral responses.
    Of note, due to their pelagic distribution, small size, and cryptic 
behavior, pygmy sperm whales and dwarf sperm whales are rarely sighted 
during at-sea surveys and difficult to distinguish between when 
visually observed in the field. Accordingly, abundance estimates in 
NMFS SARs are recorded for Kogia spp. only, density and take estimates 
in this rule are similarly lumped for the two species, and there is no 
additional information by which NMFS could appropriately apportion 
impacts other than equally/proportionally across the two species.
    No mortality of Kogia spp. is anticipated or authorized. While it 
is likely that the majority of the individuals of these two species 
will be impacted briefly on one or more days during a year of activity 
by one type of survey or another, based on the nature of the individual 
exposures and takes, as well as the aggregated scale of the impacts 
across the GOM, and in consideration of the mitigation discussed here, 
the impacts of the expected takes from these activities are not likely 
to adversely impact the GOM stocks of dwarf or pygmy sperm whales 
through adverse impacts on annual rates of recruitment or survival.

[[Page 946]]

Other Stocks

    In consideration of the similarities in the nature and scale of 
impacts, we consider the GOM stocks of the following species together 
in this section: rough-toothed dolphin, Clymene dolphin, Atlantic 
spotted dolphin, pantropical spotted dolphin, striped dolphin, Fraser's 
dolphin, Risso's dolphin, melon-headed whale, pygmy killer whale, false 
killer whale, killer whale, and short-finned pilot whale. With the 
exception of Fraser's dolphin, rough-toothed dolphin, and striped 
dolphin, estimated (and allowable) take of these stocks (including both 
the maximum annual take and the total take over 5 years) has been 
reduced as compared to the 2021 final rule.
    The risk assessment analysis, which evaluated the relative 
significance of the aggregated impacts of the survey activities across 
seven GOM zones in the context of the vulnerability of each species, 
concluded that the GOM-wide risk ratings for high and moderate effort 
scenarios ranged from very low to between low and moderate for these 
species. For the Fraser's dolphin, evaluated risk is the same as what 
was considered in the 2021 notice of issuance of the final rule, 
despite increased take numbers (see Tables 5-6).
    We further considered the likely severity of any predicted 
behavioral disruption of the individuals of these species in the 
context of the likely duration of exposure above Level B harassment 
thresholds. Specifically, the average modeled time per day spent at 
received levels above 160 dB rms (where 50 percent of the exposed 
population is considered taken) ranges from 1.4-11.7 minutes for 2D, 3D 
NAZ, and 3D WAZ surveys and up to 25.7 minutes for coil surveys (which 
comprise less than 10 percent of the total projected activity days). 
The average time per day spent between 140 and 160 dB rms for 
individuals that are taken is from 8-58.1 minutes, with the one 
exception of killer whales exposed to noise from coil surveys, which 
average 73.6 minutes (though we note that the overall risk rating for 
the blackfish group, including killer whales, is low).
    Odontocetes echolocate to find prey, and there are many different 
strategies for hunting. One common pattern for deeper-diving species is 
to conduct multiple repeated deep dives within a feeding bout, and 
multiple bouts within a day, to find and catch prey. While exposures of 
the shorter durations noted above could potentially interrupt a dive or 
cause an individual to relocate to feed, such a short-duration 
interruption would be unlikely to have significant impacts on an 
individual's energy budget and, further, for these species and this 
open-ocean area, there are no specific known reasons (i.e., these 
species range GOM-wide beyond the continental slope and there are no 
known biologically important areas) to expect that there would not be 
adequate alternate feeding areas relatively nearby, especially 
considering the anticipated absence of survey activity in the eastern 
GOM. For those species that are more shallow feeding species, it is 
unlikely that the noise exposure considered herein would result in 
minimal significant disruption of foraging behavior and, therefore, the 
corresponding energetic effects would similarly be minimal.
    Of note, the Atlantic spotted dolphin can be expected to benefit 
(via lessening of both number and severity of takes) from the coastal 
waters time-area restriction developed to benefit bottlenose dolphins 
and several additional species can be expected to benefit from the 
absence of survey activity in important eastern GOM habitat.
    No mortality or Level A harassment of these species is anticipated 
or authorized. It is likely that the majority of the individuals of 
these species will be impacted briefly on one or more days during a 
year of activity by one type of survey or another. Based on the nature 
of the individual exposures and takes, as well as the very low to low 
aggregated scale of the impacts across the GOM and considering the 
mitigation discussed here, the impacts of the expected takes from these 
activities are not likely to adversely impact the GOM stocks of any of 
these 12 GOM stocks of these species through adverse impacts on annual 
rates of recruitment or survival.

Determination

    Based on the analysis contained herein, and the analysis 
incorporated by reference from the 2021 final rule for the other 
species and stocks for which take is authorized (Table 6), of the 
likely effects of the specified activities on marine mammals and their 
habitat, and taking into consideration the implementation of the 
monitoring and mitigation measures, NMFS preliminarily finds that the 
total marine mammal take from the specified activities for the 5-year 
period of the regulations will have a negligible impact on all affected 
marine mammal species and stocks.

Small Numbers

    Below for reference, we summarize how NMFS interprets and applies 
the small numbers standard, which is substantively unchanged from the 
full discussion provided in the 2018 notice of proposed rulemaking. 
Additional discussion was provided in the Comments and Responses 
section of the notice of issuance for the 2021 final rule to address 
specific comments, questions, or recommendations received from the 
public.
    In summary, when quantitative take estimates of individual marine 
mammals are available or inferable through consideration of additional 
factors, and the number of animals taken is one-third or less of the 
best available abundance estimate for the species or stock, NMFS 
considers it to be of small numbers. For additional discussion, please 
see NMFS' notice of issuance for the 2021 final rule (86 FR 5322, 
January 19, 2021; see 86 FR 5363, 86 FR 5438). NMFS may also 
appropriately find that one or two predicted group encounters will 
result in small numbers of take relative to the range and distribution 
of a species, regardless of the estimated proportion of the abundance.
    Further, our 2021 final rule also concluded that NMFS can 
appropriately elect to make a ``small numbers'' finding based on the 
estimated annual take in individual LOAs issued under the rule. This 
approach does not affect the negligible impact analysis for a rule, 
which is the biologically relevant inquiry and based on the total 
annual estimated taking for all activities the regulations will govern. 
NMFS determined this approach is a permissible interpretation of the 
relevant MMPA provisions. Making the small numbers finding based on the 
estimated annual take in individual LOAs allows NMFS to take advantage 
of the associated administrative and environmental benefits of 
utilizing section 101(a)(5)(A) that would be precluded in many cases if 
small numbers were required to be applied to the total annual taking 
under the regulations.
    Regarding how small numbers will be evaluated under this rule, as 
in the 2021 final rule, up-to-date species information is available, 
and sophisticated models have been used to estimate take in a manner 
that will allow for quantitative comparison of the take of individuals 
versus the best available abundance estimates for the species or 
guilds. Specifically, while the modeling effort utilized in the rule 
enumerates the estimated instances of

[[Page 947]]

takes that will occur across days as the result of the operation of 
certain survey types in certain areas, the modeling report also 
includes the evaluation of a test scenario that allows for a reasonable 
modification of those generalized take estimates to better estimate the 
number of individuals that will be taken within one survey (as 
discussed under Estimated Take). Use of modeling results from the rule 
allows one to reasonably estimate the number of marine mammal 
individuals taken in association with survey activities. The estimated 
take of marine mammals for each species or guild will then be compared 
against the best available abundance estimate as determined, and 
estimates that do not exceed one-third of that estimate will be 
considered small numbers.
    Our 2021 final rule contained a fuller explanation of this 
interpretation and application of ``small numbers'' and explained how 
small numbers would be evaluated under the rule. We do not propose any 
changes to our treatment of the small numbers standard in this proposed 
rule, as the new information considered herein has no bearing on those 
discussions. See the ``Small Numbers'' section of the 2021 final rule 
at 86 FR 5438-5440 and responses to comments on small numbers at 86 FR 
5363-5368 (January 19, 2021).

Adaptive Management

    The regulations governing the take of marine mammals incidental to 
geophysical survey activities contain an adaptive management component. 
We do not propose any changes here. The comprehensive reporting 
requirements (see the Proposed Monitoring and Reporting section) are 
designed to provide NMFS with monitoring data from the previous year to 
allow consideration of whether any changes are appropriate. The use of 
adaptive management allows NMFS to consider new information from 
different sources to determine (with input from the LOA-holders 
regarding practicability) on a regular (e.g., annual or biennial) basis 
if mitigation or monitoring measures should be modified (including 
additions or deletions). Mitigation measures could be modified if new 
data suggest that such modifications would have a reasonable likelihood 
of reducing adverse effects to marine mammal species or stocks or their 
habitat and if the measures are practicable. The adaptive management 
process and associated reporting requirements would serve as the basis 
for evaluating performance and compliance. As no changes to the 
existing adaptive management process are proposed, we do not repeat 
discussion provided in the notice of issuance of the final rule. Please 
see that document for further detail.
    Under this rule, NMFS plans to implement an annual adaptive 
management process including BOEM, the Bureau of Safety and 
Environmental Enforcement (BSEE), industry operators (including 
geophysical companies as well as exploration and production companies), 
and others as appropriate. Industry operators may elect to be 
represented in this process by their respective trade associations. 
NMFS, BOEM, and BSEE (i.e., the regulatory agencies) and industry 
operators who have conducted or contracted for survey operations in the 
GOM in the prior year (or their representatives) will provide an 
agreed-upon description of roles and responsibilities, as well as 
points of contact, in advance of each year's adaptive management 
process. The foundation of the adaptive management process will be the 
annual comprehensive reports produced by LOA-holders (or their 
representatives), as well as the results of any relevant research 
activities, including research supported voluntarily by the oil and gas 
industry and research supported by the Federal government.
    All reporting requirements have been complied with under the rule 
to date. NMFS has received a report compiled by industry trade 
associations in order to comply with the comprehensive reporting 
requirements. The report, which considers LOA-specific reports received 
during the first year of implementation of the rule, is available 
online at: www.fisheries.noaa.gov/action/incidental-take-authorization-oil-and-gas-industry-geophysical-survey-activity-gulf-mexico.

Monitoring Contribution Through Other Research

    NMFS' MMPA implementing regulations require that applicants for 
incidental take authorizations describe the suggested means of 
coordinating research opportunities, plans, and activities relating to 
reducing incidental taking and evaluating its effects (50 CFR 
216.104(a)(14)). Such coordination can serve as an effective supplement 
to the monitoring and reporting required pursuant to issued LOAs and/or 
incidental take regulations. NMFS expects that relevant research 
efforts will inform the annual adaptive management process described 
above, and that levels and types of research efforts will change from 
year to year in response to identified needs and evolutions in 
knowledge, emerging trends in the economy and available funding, and 
available scientific and technological resources. In the 2018 notice of 
proposed rulemaking, NMFS described examples of relevant research 
efforts (83 FR 29300-29301, June 22, 2018). We do not repeat that 
information here, but refer the reader to that notice for more 
information. The described efforts may not be predictive of any future 
levels and types of research efforts. Research occurring in locations 
other than the GOM may be relevant to understanding the effects of 
geophysical surveys on marine mammals or marine mammal populations or 
the effectiveness of mitigation. NMFS also refers the reader to the 
industry Joint Industry Program (JIP) website 
(www.soundandmarinelife.org), which hosts a database of available 
products funded partially or fully through the JIP, and to BOEM's 
Environmental Studies Program (ESP), which develops, funds, and manages 
scientific research to inform policy decisions regarding outer 
continental shelf resource development (www.boem.gov/studies).

Impact on Availability of Affected Species for Taking for Subsistence 
Uses

    There are no relevant subsistence uses of marine mammals implicated 
by these actions. Therefore, as with the 2021 final rule, NMFS has 
determined that the total taking of affected species or stocks will not 
have an unmitigable adverse impact on the availability of such species 
or stocks for taking for subsistence purposes.

Endangered Species Act (ESA)

    Section 7 of the ESA requires Federal agencies to insure that their 
actions are not likely to jeopardize the continued existence of 
endangered or threatened species or adversely modify or destroy their 
designated critical habitat. Federal agencies must consult with NMFS 
for actions that may affect such species under NMFS' jurisdiction or 
critical habitat designated for such species. At the conclusion of 
consultation, the consulting agency provides an opinion stating whether 
the Federal agency's action is likely to jeopardize the continued 
existence of ESA-listed species or destroy or adversely modify 
designated critical habitat.
    On March 13, 2020, NMFS' Office of Protected Resources, ESA 
Interagency Cooperation Division, issued a Biological Opinion (BiOp) on 
federally regulated oil and gas program activities in the Gulf of 
Mexico, including NMFS' issuance of the ITR and subsequent LOAs (as 
well as all BOEM and Bureau of Safety and Environmental Enforcement 
approvals of activities

[[Page 948]]

associated with the OCS oil and gas program in the GOM). The 2020 BiOp 
concluded that NMFS' proposed action was not likely to jeopardize the 
continued existence of sperm whales or Rice's whales. Of note, that 
BiOp evaluated the larger scope of survey activity originally 
contemplated for the rule, before BOEM revised the scope of its 
activity to remove the GOMESA area in the eastern GOM. The take 
estimates being considered for this proposed rule are, therefore, 
within the scope of take considered in the BiOp and do not reveal 
effects of the action that may affect listed species or critical 
habitat in a manner or to an extent not previously considered. Thus, 
for this proposed rule to consider corrected take estimates and other 
newly available information, NMFS has preliminarily determined that re-
initiation of consultation is not triggered under 50 CFR 402.16, 
although NMFS does anticipate amending the incidental take statement to 
reflect the corrected take estimates.

Letters of Authorization

    Under the incidental take regulations in effect for this specified 
activity, industry operators may apply for LOAs (50 CFR 217.186). We do 
not propose any changes to the regulations for obtaining an LOA. LOAs 
may be issued for any time period that does not exceed the effective 
period of the regulations, provided that NMFS is able to make the 
relevant determinations (50 CFR 217.183). Because the specified 
activity does not provide actual specifics of the timing, location, and 
survey design for activities that would be the subject of issued LOAs, 
such requests must include, at minimum, the information described at 50 
CFR 216.104(a)(1) and (2), and should include an affirmation of intent 
to adhere to the mitigation, monitoring, and reporting requirements 
described in the regulations. The level of effort proposed by an 
operator would be used to develop an LOA-specific take estimate based 
on the results of Weirathmueller et al. (2022). These results would be 
based on the appropriate source proxy (i.e., either 90-in\3\ single 
airgun or 4,130-, 5,110-, or 8,000-in\3\ airgun array).
    As is the case now under the 2021 ITR, if applicants do not use the 
modeling provided by the rule, NMFS may publish a notice in the Federal 
Register soliciting public comment, if the model or inputs differ 
substantively from those that have been reviewed by NMFS and the public 
previously. Additional public review is not needed unless the model or 
inputs differ substantively from those that have been reviewed by NMFS 
and the public previously.
    Technologies continue to evolve to meet the technical, 
environmental, and economic challenges of oil and gas development. The 
use of ``new and unusual technologies'' (NUT), i.e., technologies other 
than those described herein, will be evaluated on a case-by-case basis 
and may require public review. Some seemingly new technologies proposed 
for use by operators are often extended applications of existing 
technologies and interface with the environment in essentially the same 
way as well-known or conventional technologies. For such evaluations, 
NMFS will follow the existing NUT process described in the notice of 
issuance for the 2021 final rule. Please see that document for further 
detail.

Classification

    Pursuant to the procedures established to implement Executive Order 
12866, the Office of Management and Budget (OMB) determined that the 
2021 final rule was economically significant. Accordingly, a regulatory 
impact analysis (RIA) was prepared and made available for review by the 
public. Following review of public comments, a final RIA was prepared 
and made available online at: www.fisheries.noaa.gov/action/incidental-take-authorization-oil-and-gas-industry-geophysical-survey-activity-gulf-mexico. Appendix B of the RIA provided a final regulatory 
flexibility analysis (FRFA, discussed below), while Appendix C 
addressed other compliance requirements. The RIA demonstrated that the 
rule would not be economically significant and, in fact, that the rule 
would provide cost benefits to the regulated industry when evaluated 
against the settlement baseline. Please see the RIA for additional 
detail.
    OMB has determined that this proposed rule is significant under 
section 3(f)(1) of E.O. 12866.
    NMFS prepared a FRFA, as required by section 603 of the Regulatory 
Flexibility Act (RFA), for the regulations issued under the 2021 final 
rule, which we do not propose to change in this proposed rule. The FRFA 
described the economic effects on small entities. A copy of the full 
FRFA is available as Appendix B to the RIA. No changes are proposed 
here that would affect the findings of the FRFA, which were summarized 
in the notice of issuance for the 2021 final rule (86 FR 5443, January 
19, 2021).
    Pursuant to section 605(b) of the Regulatory Flexibility Act (RFA), 
the Chief Counsel for Regulation of the Department of Commerce has 
certified to the Chief Counsel for Advocacy of the Small Business 
Administration that this proposed rule, if adopted, would not have a 
significant economic impact on a substantial number of small entities. 
As discussed above, no changes are proposed through this rule that 
would result in additional economic effects to small entities. Because 
of this certification, a regulatory flexibility analysis is not 
required, and none has been prepared.
    This proposed rule does not contain a change to a collection of 
information requirement for purposes of the Paperwork Reduction Act of 
1995. The existing collection of information requirements would 
continue to apply under the following OMB Control Number(s): 0648-0151.
    Notwithstanding any other provision of the law, no person is 
required to respond to, nor shall any person be subject to a penalty 
for failure to comply with, a collection of information subject to the 
requirements of the PRA, unless that collection of information displays 
a currently valid OMB Control Number.

List of Subjects in 50 CFR Part 217

    Exports, Fish, Imports, Indians, Labeling, Marine mammals, 
Penalties, Reporting and recordkeeping requirements, Seafood, 
Transportation.

    As described above, because NMFS does not find that new mitigation 
measures are required, this proposed rule would not amend the current 
applicable regulations at 50 CFR part 217 subpart S (Sec. Sec.  217.180 
through 217.189). Thus, no amendatory instructions are necessary.

Samuel D. Rauch, III,
Deputy Assistant Administrator for Regulatory Programs, National Marine 
Fisheries Service.
[FR Doc. 2022-28208 Filed 1-4-23; 8:45 am]
BILLING CODE 3510-22-P