Takes of Marine Mammals Incidental to Specified Activities; Taking Marine Mammals Incidental to a Marine Geophysical Survey of the Blake Plateau in the Northwest Atlantic Ocean, 45172-45190 [2023-14946]

Agencies

• DEPARTMENT OF COMMERCE
• National Oceanic and Atmospheric Administration

[Federal Register Volume 88, Number 134 (Friday, July 14, 2023)]
[Notices]
[Pages 45172-45190]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2023-14946]


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DEPARTMENT OF COMMERCE

National Oceanic and Atmospheric Administration

[RTID 0648-XD119]


Takes of Marine Mammals Incidental to Specified Activities; 
Taking Marine Mammals Incidental to a Marine Geophysical Survey of the 
Blake Plateau in the Northwest Atlantic Ocean

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

ACTION: Notice; issuance of an incidental harassment authorization.

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SUMMARY: In accordance with the regulations implementing the Marine 
Mammal Protection Act (MMPA) as amended, notification is hereby given 
that NMFS has issued an incidental harassment authorization (IHA) to 
Lamont-Doherty Earth Observatory (L-DEO) to incidentally harass marine 
mammals during a marine geophysical survey of the Blake Plateau in the 
northwest Atlantic Ocean.

DATES: This authorization is effective from July 10, 2023 through July 
9, 2024.

ADDRESSES: Electronic copies of the application and supporting 
documents, as well as a list of the references cited in this document, 
may be obtained online at: https://www.fisheries.noaa.gov/action/incidental-take-authorization-lamont-doherty-earth-observatorys-marine-geophysical-surveys. In case of problems accessing these documents, 
please call the contact listed below.

FOR FURTHER INFORMATION CONTACT: Jenna Harlacher, Office of Protected 
Resources (OPR) NMFS, (301) 427-8401.

SUPPLEMENTARY INFORMATION:

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 proposed or, if the taking is limited to harassment, a notice of a 
proposed IHA is provided to the public for review.

[[Page 45173]]

    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 in shorthand as 
``mitigation''); and requirements pertaining to the mitigation, 
monitoring and reporting of the takings are set forth. The definitions 
of all applicable MMPA statutory terms cited above are included in the 
relevant sections below.

Summary of Request

    On November 22, 2022, NMFS received a request from L-DEO for an IHA 
to take marine mammals incidental to a marine geophysical survey of the 
Blake Plateau in the northwest Atlantic Ocean. The application was 
deemed adequate and complete on February 1, 2023. L-DEO's request is 
for take of 29 marine mammal species by Level B harassment, and for 4 
of these species, by Level A harassment. Neither L-DEO nor NMFS expect 
serious injury or mortality to result from this activity and, 
therefore, an IHA is appropriate.

Description of Activity

Overview

    Researchers from the University of Texas Institute of Geophysics 
(UTIG) and L-DEO, with funding from the National Science Foundation 
(NSF), plan to conduct research, including high-energy seismic surveys 
using airguns as the acoustic source, from the research vessel (R/V) 
Marcus G. Langseth (Langseth). The surveys would occur in the Blake 
Plateau in the northwest Atlantic Ocean during summer or fall 2023. The 
planned multi-channel seismic (MCS) reflection and Ocean Bottom 
Seismometers (OBS) seismic refraction surveys would occur within the 
Exclusive Economic Zone (EEZ) of the United States and Bahamas and in 
international waters, in depths ranging from >100 to 5,200 meters (m).
    To complete this survey, the R/V Langseth would tow a 36-airgun 
array consisting of a mixture of Bolt airguns ranging from 40 to 360 
cubic inches (in\3\) (1-9.1 m\3\) each on four strings spaced 16 m 
apart, with a total discharge volume of 6,600 in\3\ (167.6 m\3\). The 
airgun array would be towed at 10-12 m deep along the survey lines, 
while the receiving systems for the different survey segments would 
consist of a 15 kilometer (km) long solid-state hydrophone streamer and 
approximately 40 OBS, respectively. The airguns would fire at a shot 
interval of 50 m (~24 seconds (s)) during multi-channel seismic (MCS) 
reflection surveys with the hydrophone streamer and at a 200-m (~78 s) 
interval during Ocean Bottom Seismometer (OBS) seismic refraction 
surveys. Approximately 6682 kilometers (km) of seismic acquisition are 
planned: 5730 km of 2D MCS seismic reflection data and 952 km of OBS 
refraction data.
    The study would acquire two-dimensional (2-D) seismic reflection 
and seismic refraction data to examine the structure and evolution of 
the rifted margins of the southeastern United States, including the 
rift dynamics during the formation of the Carolina Trough and Blake 
Plateau. Additional data would be collected using a multibeam 
echosounder (MBES), a sub-bottom profiler (SBP), and an Acoustic 
Doppler Current Profiler (ADCP), which would be operated from R/V 
Langseth continuously during the seismic surveys, including during 
transit. No take of marine mammals is expected to result from use of 
this equipment.

Dates and Duration

    The survey is planned to last for approximately 61 days, spread 
between two operational legs, with 40 days of seismic operations. One 
leg would include 32 days of MCS seismic operations and 4 days of 
transit time, whereas the other leg would consist of 8 days of seismic 
operations with OBSs, 13 days of OBS deployment, and 4 days of transit. 
R/V Langseth would likely leave from and return to port in 
Jacksonville, Florida during summer or fall 2023.

Specific Geographic Region

    The survey would occur within approximately 27.5-33.5[deg] N, 74-
80[deg] W off the coasts of South Carolina to northern Florida in the 
northwest Atlantic Ocean. The distances to all state waters would be 
>80 km, and to the coast would be ~90 km off Georgia, ~98 km off 
Florida, and ~107 km off South Carolina. The region where the survey is 
planned to occur is depicted in Figure 1; the tracklines could occur 
anywhere within the polygon shown in Figure 1. Representative survey 
tracklines are shown, however, some deviation in actual tracklines, 
including the order of survey operations, could be necessary for 
reasons such as science drivers, poor data quality, inclement weather, 
or mechanical issues with the research vessel and/or equipment. The 
surveys are planned to occur within the EEZs of the United States and 
Bahamas and in international waters, in depths ranging from >100 to 
5,200 m deep.

[[Page 45174]]

[GRAPHIC] [TIFF OMITTED] TN14JY23.003

Figure 1--Location of the Blake Plateau Seismic Surveys in the 
Northwest Atlantic Ocean

Representative survey tracklines are included in the figure; however, 
the tracklines could occur anywhere within the survey area. MPA = 
marine protected area; NMS = National Marine Sanctuary. EBSA = 
Ecologically or Biologically Significant Marine Areas. CBD = Convention 
on Biological Diversity. N = North.

    A detailed description of the planned geophysical survey was 
provided in the Federal Register notice of the proposed IHA (88 FR 
37390; June 7, 2023). Since that time, no changes have been made to the 
planned survey activities. Therefore, a detailed description is not 
provided here. Please refer to that Federal Register notice for the 
description of the specified activity.

Comments and Responses

    A notice of NMFS' proposal to issue an IHA to L-DEO was published 
in the Federal Register on June 7, 2023 (88 FR 37390), beginning a 30-
day comment period. That notice described, in detail, L-DEO's 
activities, the marine mammal species that may be affected by the 
activities, and the anticipated effects on marine mammals. In that 
notice, we requested public input on the request for authorization 
described therein, our analyses, the proposed authorization, and any 
other aspect of the notice of proposed IHA, and requested that 
interested persons submit relevant information, suggestions, and 
comments. NMFS received no relevant or substantive public comments.

Changes From the Proposed IHA to Final IHA

    Changes were made between publication of the notice of proposed IHA 
and this notice of final IHA, including correction of typographical 
errors in the draft IHA and the Federal Register notice of proposed 
IHA. Additionally, language has been added to the reporting requirement 
clarifying that if no comments are received from NMFS within 30 days of 
receiving the draft that the report is considered final. Finally, the 
FRN was updated to note the correct period of time that airgun 
operations can continue while there is a PAM malfunction (10 hours), as 
was stated in the draft IHA provided for public review.

Description of Marine Mammals in the Area of Specified Activities

    Sections 3 and 4 of L-DEO's application summarize available 
information regarding status and trends, distribution and habitat 
preferences, and behavior and life history of the potentially affected 
species. NMFS fully considered all of this information, and we refer 
the reader to these descriptions, instead of reprinting the 
information. Additional information regarding population trends and 
threats may be found in NMFS' Stock Assessment Reports (SARs; 
www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessments) and more general information about these species 
(e.g., physical and behavioral descriptions) may be found on NMFS' 
website (https://www.fisheries.noaa.gov/find-species). NMFS refers the 
reader to the application and to the aforementioned sources for general 
information regarding the species listed in Table 1.
    Table 1 lists all species or stocks for which take is expected and 
authorized for this activity, and summarizes information related to the 
population or stock, including regulatory status under the MMPA and 
Endangered Species Act (ESA) and potential biological removal (PBR), 
where known. PBR is 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

[[Page 45175]]

that stock to reach or maintain its optimum sustainable population (as 
described in NMFS' SARs). While no serious injury or mortality is 
anticipated or authorized here, PBR and annual serious injury and 
mortality from anthropogenic sources are included here as gross 
indicators of the status of the species or stocks and other threats.
    Marine mammal abundance estimates presented in this document 
represent the total number of individuals that make up a given stock or 
the total number estimated within a particular study or survey area. 
NMFS' stock abundance estimates for most species represent the total 
estimate of individuals within the geographic area, if known, that 
comprises that stock. For some species, this geographic area may extend 
beyond U.S. waters. All stocks managed under the MMPA in this region 
are assessed in NMFS' U.S. Atlantic and Gulf of Mexico SARs (e.g., 
Hayes et al., 2019, 2020, 2022). All values presented in Table 1 are 
the most recent available (including the draft 2022 SARs) at the time 
of publication and are available online at: www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessments.

                                              Table 1--Species Likely Impacted by the Specified Activities
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                                                                                  ESA/MMPA status;  Stock abundance  (CV,    Modeled              Annual
            Common name                Scientific name             Stock           Strategic (Y/N)    Nmin, most recent     abundance     PBR      M/SI
                                                                                         \1\        abundance survey) \2\      \5\                 \3\
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                          Order Cetartiodactyla--Cetacea--Superfamily Mysticeti (baleen whales)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Family Balaenopteridae (rorquals):
    Humpback whale................  Megaptera              Gulf of Maine........  -/-; N            1,396 (0; 1,380;         \7\ 2,259       22    12.15
                                     novaeangliae.                                                   2016).
    Fin whale.....................  Balaenoptera physalus  Western North          E/D; Y            6,802 (0.24; 5,573;      \6\ 3,587       11      1.8
                                                            Atlantic.                                2016).
    Sei whale.....................  Balaenoptera borealis  Nova Scotia..........  E/D; Y            6,292 (1.02; 3,098;      \6\ 1,043      6.2      0.8
                                                                                                     2016).
    Minke whale...................  Balaenoptera           Canadian East Coast..  -/-; N            21,968 (0.31; 17,002;    \6\ 4,044      170     10.6
                                     acutorostrata.                                                  2016).
    Blue whale....................  Balaenoptera musculus  Western North          E/D; Y            unk (unk; 402; 1980-        \7\ 33      0.8        0
                                                            Atlantic.                                2008).
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                            Superfamily Odontoceti (toothed whales, dolphins, and porpoises)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Family Physeteridae:
    Sperm whale...................  Physeter               North Atlantic.......  E/D; Y            4,349 (0.28; 3,451;      \6\ 6,576      3.9        0
                                     macrocephalus.                                                  2016).
Family Kogiidae:
    Pygmy sperm whale.............  Kogia breviceps......  Western North          -/-; N            7,750 (0.38; 5,689;      \7\ 7,980       46        0
                                                            Atlantic.                                2016).
    Dwarf sperm whale.............  Kogia sima...........  Western North          -/-; N
                                                            Atlantic.
Family Ziphiidae (beaked whales):
    Cuvier's beaked Whale.........  Ziphius cavirostris..  Western North          -/-; N            5,744 (0.36, 4,282,      \7\ 5,588       43      0.2
                                                            Atlantic.                                2016).
    Blainville's beaked Whale.....  Mesoplodon             Western North          -/-; N            10,107 (0.27; 8,085;     \7\ 6,526   \4\ 81    \4\ 0
                                     densirostris.          Atlantic.                                2016) \4\.
    True's beaked whale...........  Mesoplodon mirus.....  Western North          -/-; N
                                                            Atlantic.
    Gervais' beaked whale.........  Mesoplodon europaeus.  Western North          -/-; N
                                                            Atlantic.
Family Delphinidae:
    Long-finned pilot whale.......  Globicephala melas...  Western North          -/-; N            39,215 (0.30; 30,627;      \7\ \8\      306        9
                                                            Atlantic.                                2016).                     23,905
    Short finned pilot whale......  Globicephala           Western North          -/-; Y            28,924 (0.24; 23,637;                   236      136
                                     macrorhynchus.         Atlantic.                                2016).
    Rough-toothed dolphin.........  Steno bredanensis....  Western North          -/-; N            136 (1.0; 67; 2016)..    \7\ 1,011      0.7        0
                                                            Atlantic.
    Bottlenose dolphin............  Tursiops truncatus...  Western North          -/-; N            62,851 (0.23; 51,914,   \6\ 68,739      519       28
                                                            Atlantic Offshore.                       2016).
    Pantropical spotted dolphin...  Stenella attenuata...  Western North          -/-; N            6,593 (0.52; 4,367;      \7\ 1,403       44        0
                                                            Atlantic.                                2016).
    Atlantic spotted dolphin......  Stenella frontalis...  Western North          -/-; N            39,921 (0.27; 32,032;   \6\ 39,352      320        0
                                                            Atlantic.                                2016).
    Spinner dolphin...............  Stenella longirostris  Western North          -/-; N            4,102 (0.99; 2,045;        \7\ 885       21        0
                                                            Atlantic.                                2016).
    Clymene dolphin...............  Stenella clymene.....  Western North          -/-; N            4,237 (1.03; 2,071;      \7\ 8,576       21        0
                                                            Atlantic.                                2016).
    Striped dolphin...............  Stenella coeruleoalba  Western North          -/-; N            67,036 (0.29; 52,939;   \7\ 54,707      529        0
                                                            Atlantic.                                2016).
    Fraser's dolphin..............  Lagenodelphis hosei..  Western North          -/-; N            unk..................      \7\ 658      unk        0
                                                            Atlantic.
    Risso's dolphin...............  Grampus griseus......  Western North          -/-; N            35,215(0.19; 30,051;    \6\ 24,260      301       34
                                                            Atlantic.                                2016).
    Common dolphin................  Delphinus delphis....  Western North          -/-; N            172,947 (0.21;         \6\ 144,036    1,452      390
                                                            Atlantic.                                145,216; 2016).
    Melon-headed whale............  Peponocephala electra  Western North          -/-; N            unk..................      \7\ 618      unk        0
                                                            Atlantic.
    Pygmy killer whale............  Feresa attenuate.....  Western North          -/-; N            unk..................       \7\ 68      unk        0
                                                            Atlantic.
    False killer whale............  Pseudorca crassidens.  Western North          -/-; N            1,791 (0.56; 1,154;        \7\ 139       12        0
                                                            Atlantic.                                2016).
    Killer whale..................  Orcinus orca.........  Western North          -/-; N            unk..................       \7\ 73      unk        0
                                                            Atlantic.
Family Phocoenidae (porpoises):

[[Page 45176]]

 
    Harbor porpoise...............  Phocoena phocoena....  Gulf of Maine/Bay of   -/-; N            95,543 (0.31; 74,034;   \6\ 55,049      851      164
                                                            Fundy.                                   2016).
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\1\ ESA status: Endangered (E), Threatened (T)/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: https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessment-reports-region/. CV is coefficient of variation; Nmin is the minimum estimate of stock abundance; unknown (unk).
\3\ 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). Annual mortality or serious injury (M/SI) often cannot be determined precisely and is in some cases presented as a minimum
  value or range.
\4\ The values for Mesoplodont beaked whales would also represent Sowerby's beaked whales, which are not expected to occur in the survey area.
\5\ Modeled abundance from Roberts et al. (2023).
\6\ Averaged monthly (May-Oct) abundance.
\7\ Only single annual abundance given.
\8\ Modeled abundance for pilot whale is grouped together for both short-finned and long-finned pilot whales.

    As indicated above, all 29 species in Table 1 temporally and 
spatially co-occur with the activity to the degree that take is 
reasonably likely to occur. Species that could potentially occur in the 
research area but are not likely to be harassed due to the rarity of 
their occurrence (i.e., are considered extralimital or rare visitors to 
the waters of the northwest Atlantic Ocean), or because their known 
migration through the area does not align with the survey dates, were 
omitted.
    A detailed description of the of the species likely to be affected 
by the geophysical survey, including brief introductions to the species 
and relevant stocks as well as available information regarding 
population trends and threats, and information regarding local 
occurrence, were provided in the Federal Register notice for the 
proposed IHA (88 FR 37390, June 7, 2023). Since that time, we are not 
aware of any changes in the status of these species and stocks; 
therefore, detailed descriptions are not provided here. Please refer to 
that Federal Register notice for these descriptions. Please also refer 
to NMFS' website (https://www.fisheries.noaa.gov/find-species) for 
generalized species accounts.

Marine Mammal Hearing

    Hearing is the most important sensory modality for marine mammals 
underwater, and exposure to anthropogenic sound can have deleterious 
effects. To appropriately assess the potential effects of exposure to 
sound, it is necessary to understand the frequency ranges marine 
mammals are able to hear. Not all marine mammal species have equal 
hearing capabilities (e.g., Richardson et al., 1995; Wartzok and 
Ketten, 1999; Au and Hastings, 2008). To reflect this, Southall et al. 
(2007, 2019) recommended that marine mammals be divided into hearing 
groups based on directly measured (behavioral or auditory evoked 
potential techniques) or estimated hearing ranges (behavioral response 
data, anatomical modeling, etc.). Note that no direct measurements of 
hearing ability have been successfully completed for mysticetes (i.e., 
low-frequency (LF) cetaceans). Subsequently, NMFS (2018) described 
generalized hearing ranges for these marine mammal hearing groups. 
Generalized hearing ranges were chosen based on the approximately 65 
decibel (dB) threshold from the normalized composite audiograms, with 
the exception for lower limits for LF cetaceans where the lower bound 
was deemed to be biologically implausible and the lower bound from 
Southall et al. (2007) retained. Marine mammal hearing groups and their 
associated hearing ranges are provided in Table 2.

                  Table 2--Marine Mammal Hearing Groups
                              [NMFS, 2018]
------------------------------------------------------------------------
               Hearing group                 Generalized hearing range *
------------------------------------------------------------------------
Low-frequency (LF) cetaceans (baleen         7 Hz to 35 kHz.
 whales).
Mid-frequency (MF) cetaceans (dolphins,      150 Hz to 160 kHz.
 toothed whales, beaked whales, bottlenose
 whales).
High-frequency (HF) cetaceans (true          275 Hz to 160 kHz.
 porpoises, Kogia, river dolphins,
 Cephalorhynchid, Lagenorhynchus cruciger &
 L. australis).
Phocid pinnipeds (PW) (underwater) (true     50 Hz to 86 kHz.
 seals).
Otariid pinnipeds (OW) (underwater) (sea     60 Hz to 39 kHz.
 lions and fur seals).
------------------------------------------------------------------------
* Represents the generalized hearing range for the entire group as a
  composite (i.e., all species within the group), where individual
  species' hearing ranges are typically not as broad. Generalized
  hearing range chosen based on ~65 dB threshold from normalized
  composite audiogram, with the exception for lower limits for LF
  cetaceans (Southall et al., 2007) and PW pinniped (approximation).

    For more detail concerning these groups and associated frequency 
ranges, please see NMFS (2018) for a review of available information.

Potential Effects of Specified Activities on Marine Mammals and Their 
Habitat

    The effects of underwater noise from L-DEO's survey activities have 
the potential to result in harassment of marine mammals in the vicinity 
of the survey area. The notice of proposed IHA (88 FR 37390, June 7, 
2023) included a discussion of the effects of anthropogenic noise on 
marine mammals and the potential effects of underwater noise from L-DEO 
on marine mammals and their habitat. That information and analysis is 
not repeated here; please refer to the notice of

[[Page 45177]]

proposed IHA (88 FR 37390, June 7, 2023).

Estimated Take of Marine Mammals

    This section provides an estimate of the number of incidental takes 
authorized through the IHA, which will inform both NMFS' consideration 
of ``small numbers,'' and the negligible impact determinations.
    Harassment is the only type of take expected to result from these 
activities. 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).
    Anticipated takes would primarily be Level B harassment, as use of 
the airgun arrays have the potential to result in disruption of 
behavioral patterns of marine mammals. There is also some potential for 
auditory injury (Level A harassment) to result for species of certain 
hearing groups due to the size of the predicted auditory injury zones 
for those groups. Auditory injury is less likely to occur for MF 
species, due to their relative lack of sensitivity to the frequencies 
at which the primary energy of an airgun signal is found, as well as 
such species' general lower sensitivity to auditory injury as compared 
to HF cetaceans. As discussed in further detail below, we do not expect 
auditory injury for MF cetaceans. The mitigation and monitoring 
measures are expected to minimize the severity of such taking to the 
extent practicable. No mortality is anticipated as a result of these 
activities. Below we describe how the take numbers are estimated.
    For acoustic impacts, generally speaking, we estimate take by 
considering: (1) acoustic thresholds above which NMFS believes the best 
available science indicates marine mammals will be behaviorally 
harassed or incur some degree of permanent hearing impairment; (2) the 
area or volume of water that will be ensonified above these levels in a 
day; (3) the density or occurrence of marine mammals within these 
ensonified areas; and, (4) the number of days of activities. We note 
that while these factors can contribute to a basic calculation to 
provide an initial prediction of potential takes, additional 
information that can qualitatively inform take estimates is also 
sometimes available (e.g., previous monitoring results or average group 
size). Below, we describe the factors considered here in more detail 
and present the take estimates.

Acoustic Thresholds

    NMFS recommends the use of acoustic thresholds that identify the 
received level of underwater sound above which exposed marine mammals 
would be reasonably expected to be behaviorally harassed (equated to 
Level B harassment) or to incur Permanent Threshold Shift (PTS) of some 
degree (equated to Level A harassment).

Level B Harassment

    Though significantly driven by received level, the onset of 
behavioral disturbance from anthropogenic noise exposure is also 
informed to varying degrees by other factors related to the source or 
exposure context (e.g., frequency, predictability, duty cycle, duration 
of the exposure, signal-to-noise ratio, distance to the source), the 
environment (e.g., bathymetry, other noises in the area, predators in 
the area), and the receiving animals (hearing, motivation, experience, 
demography, life stage, depth) and can be difficult to predict (e.g., 
Southall et al., 2007, 2021; Ellison et al., 2012). Based on what the 
available science indicates and the practical need to use a threshold 
based on a metric that is both predictable and measurable for most 
activities, NMFS typically uses a generalized acoustic threshold based 
on received level to estimate the onset of behavioral harassment. NMFS 
generally predicts that marine mammals are likely to be behaviorally 
harassed in a manner considered to be Level B harassment when exposed 
to underwater anthropogenic noise above root-mean-squared pressure 
received levels (RMS SPL) of 120 dB (referenced to 1 micropascal (re 1 
[mu]Pa)) for continuous (e.g., vibratory pile driving, drilling) and 
above RMS SPL 160 dB re 1 [mu]Pa for non-explosive impulsive (e.g., 
seismic airguns) or intermittent (e.g., scientific sonar) sources. 
Generally speaking, Level B harassment take estimates based on these 
behavioral harassment thresholds are expected to include any likely 
takes by Temporary Threshold Shift (TTS) as, in most cases, the 
likelihood of TTS occurs at distances from the source less than those 
at which behavioral harassment is likely. TTS of a sufficient degree 
can manifest as behavioral harassment, as reduced hearing sensitivity 
and the potential reduced opportunities to detect important signals 
(conspecific communication, predators, prey) may result in changes in 
behavior patterns that would not otherwise occur.
    L-DEO's planned survey includes the use of impulsive seismic 
sources (e.g., Bolt airguns), and therefore the 160 dB re 1 [mu]Pa is 
applicable for analysis of Level B harassment.

Level A Harassment

    NMFS' Technical Guidance for Assessing the Effects of Anthropogenic 
Sound on Marine Mammal Hearing (Version 2.0) (Technical Guidance, 2018) 
identifies dual criteria to assess auditory injury (Level A harassment) 
to five different marine mammal groups (based on hearing sensitivity) 
as a result of exposure to noise from two different types of sources 
(impulsive or non-impulsive). L-DEO's planned survey includes the use 
of impulsive seismic sources (e.g., airguns).
    These thresholds are provided in the table below. The references, 
analysis, and methodology used in the development of the thresholds are 
described in NMFS' 2018 Technical Guidance, which may be accessed at: 
www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-acoustic-technical-guidance.

                     Table 3--Thresholds Identifying the Onset of Permanent Threshold Shift
----------------------------------------------------------------------------------------------------------------
                                                     PTS onset acoustic thresholds * (received level)
             Hearing group              ------------------------------------------------------------------------
                                                  Impulsive                         Non-impulsive
----------------------------------------------------------------------------------------------------------------
Low-Frequency (LF) Cetaceans...........  Cell 1: Lpk,flat: 219 dB;   Cell 2: LE,LF,24h: 199 dB
                                          LE,LF,24h: 183 dB.
Mid-Frequency (MF) Cetaceans...........  Cell 3: Lpk,flat: 230 dB;   Cell 4: LE,MF,24h: 198 dB
                                          LE,MF,24h: 185 dB.
High-Frequency (HF) Cetaceans..........  Cell 5: Lpk,flat: 202 dB;   Cell 6: LE,HF,24h: 173 dB
                                          LE,HF,24h: 155 dB.
Phocid Pinnipeds (PW) (Underwater).....  Cell 7: Lpk,flat: 218 dB;   Cell 8: LE,PW,24h: 201 dB
                                          LE,PW,24h: 185 dB.

[[Page 45178]]

 
Otariid Pinnipeds (OW) (Underwater)....  Cell 9: Lpk,flat: 232 dB;   Cell 10: LE,OW,24h: 219 dB
                                          LE,OW,24h: 203 dB.
----------------------------------------------------------------------------------------------------------------
* Dual metric acoustic thresholds for impulsive sounds: Use whichever results in the largest isopleth for
  calculating PTS onset. If a non-impulsive sound has the potential of exceeding the peak sound pressure level
  thresholds associated with impulsive sounds, these thresholds should also be considered.
Note: Peak sound pressure (Lpk) has a reference value of 1 [micro]Pa, and cumulative sound exposure level (LE)
  has a reference value of 1[micro]Pa\2\s. In this Table, thresholds are abbreviated to reflect American
  National Standards Institute standards (ANSI 2013). However, peak sound pressure is defined by ANSI as
  incorporating frequency weighting, which is not the intent for this Technical Guidance. Hence, the subscript
  ``flat'' is being included to indicate peak sound pressure should be flat weighted or unweighted within the
  generalized hearing range. The subscript associated with cumulative sound exposure level thresholds indicates
  the designated marine mammal auditory weighting function (LF, MF, and HF cetaceans, and PW and OW pinnipeds)
  and that the recommended accumulation period is 24 hours. The cumulative sound exposure level thresholds could
  be exceeded in a multitude of ways (i.e., varying exposure levels and durations, duty cycle). When possible,
  it is valuable for action proponents to indicate the conditions under which these acoustic thresholds will be
  exceeded.

Ensonified Area

    Here, we describe operational and environmental parameters of the 
activity that are used in estimating the area ensonified above the 
acoustic thresholds, including source levels and transmission loss 
coefficient.
    When the NMFS Technical Guidance (2016a) was published, in 
recognition of the fact that ensonified area/volume could be more 
technically challenging to predict because of the duration component in 
the new thresholds, we developed a user spreadsheet that includes tools 
to help predict a simple isopleth that can be used in conjunction with 
marine mammal density or occurrence to help predict takes. We note that 
because of some of the assumptions included in the methods used for 
these tools, we anticipate that isopleths produced are typically going 
to be overestimates of some degree, which may result in some degree of 
overestimate of Level A harassment take. However, these tools offer the 
best way to predict appropriate isopleths when more sophisticated 3D 
modeling methods are not available, and NMFS continues to develop ways 
to quantitatively refine these tools, and will qualitatively address 
the output where appropriate.
    The planned survey would entail the use of a 36-airgun array with a 
total discharge volume of 6,600 in\3\ at a tow depth of 10-12 m. L-
DEO's model results are used to determine the 160 dBrms radius for the 
36-airgun array in water depth ranging from >100 to 5,200 m. Received 
sound levels have been predicted by L-DEO's model (Diebold et al., 
2010) as a function of distance from the 36-airgun array. Models for 
the 36-airgun array used a 12-m tow depth. This modeling approach uses 
ray tracing for the direct wave traveling from the array to the 
receiver and its associated source ghost (reflection at the air-water 
interface in the vicinity of the array), in a constant-velocity half-
space (infinite homogeneous ocean layer, unbounded by a seafloor). In 
addition, propagation measurements of pulses from the 36-airgun array 
at a tow depth of 6 m have been reported in deep water (~1600 m), 
intermediate water depth on the slope (~600-1,100 m), and shallow water 
(~50 m) in the Gulf of Mexico (Tolstoy et al., 2009; Diebold et al., 
2010).
    For deep and intermediate water cases, the field measurements 
cannot be used readily to derive the harassment isopleths, as at those 
sites the calibration hydrophone was located at a roughly constant 
depth of 350-550 m, which may not intersect all the SPL isopleths at 
their widest point from the sea surface down to the assumed maximum 
relevant water depth (~2,000 m) for marine mammals. At short ranges, 
where the direct arrivals dominate and the effects of seafloor 
interactions are minimal, the data at the deep sites are suitable for 
comparison with modeled levels at the depth of the calibration 
hydrophone. At longer ranges, the comparison with the model--
constructed from the maximum SPL through the entire water column at 
varying distances from the airgun array--is the most relevant.
    In deep and intermediate water depths at short ranges, sound levels 
for direct arrivals recorded by the calibration hydrophone and L-DEO 
model results for the same array tow depth are in good alignment (see 
Figures 12 and 14 in Diebold et al., 2010). Consequently, isopleths 
falling within this domain can be predicted reliably by the L-DEO 
model, although they may be imperfectly sampled by measurements 
recorded at a single depth. At greater distances, the calibration data 
show that seafloor-reflected and sub-seafloor-refracted arrivals 
dominate, whereas the direct arrivals become weak and/or incoherent 
(see Figures 11, 12, and 16 in Diebold et al., 2010). Aside from local 
topography effects, the region around the critical distance is where 
the observed levels rise closest to the model curve. However, the 
observed sound levels are found to fall almost entirely below the model 
curve. Thus, analysis of the Gulf of Mexico calibration measurements 
demonstrates that although simple, the L-DEO model is a robust tool for 
conservatively estimating isopleths.
    The survey would acquire data with the 36-airgun array at a tow 
depth of 10-12 m. For deep water (gt;1000 m), we use the deep-water 
radii obtained from L-DEO model results down to a maximum water depth 
of 2,000 m for the 36-airgun array. The radii for intermediate water 
depths (100-1,000 m) are derived from the deep-water ones by applying a 
correction factor (multiplication) of 1.5, such that observed levels at 
very near offsets fall below the corrected mitigation curve (see Figure 
16 in Diebold et al., 2010).
    L-DEO's modeling methodology is described in greater detail in L-
DEO's application. The estimated distances to the Level B harassment 
isopleth for the airgun configuration are shown in Table 4.

[[Page 45179]]



  Table 4--Predicted Radial Distances From the R/V Langseth Seismic Source to Isopleth Corresponding to Level B
                                              Harassment Threshold
----------------------------------------------------------------------------------------------------------------
                                                                                                   Predicted
                                                                                                distances (in m)
                   Airgun configuration                      Tow depth (m)   Water depth (m)     to the Level B
                                                                                                   harassment
                                                                                                   threshold
----------------------------------------------------------------------------------------------------------------
4 strings, 36 airguns, 6,600 in\3\........................              12             >1,000          \1\ 6,733
                                                                                    100-1,000         \2\ 10,100
----------------------------------------------------------------------------------------------------------------
\1\ Distance is based on L-DEO model results.
\2\ Distance is based on L-DEO model results with a 1.5 x correction factor between deep and intermediate water
  depths.

    Table 5 presents the modeled PTS isopleths for each cetacean 
hearing group based on L-DEO modeling incorporated in the companion 
user spreadsheet (NMFS 2018).

          Table 5--Modeled Radial Distance to Isopleths Corresponding to Level A Harassment Thresholds
----------------------------------------------------------------------------------------------------------------
                                                           Low frequency      Mid frequency      High frequency
----------------------------------------------------------------------------------------------------------------
                                                   MCS Surveys
----------------------------------------------------------------------------------------------------------------
PTS SELcum.............................................              320.2                  0                  1
PTS Peak...............................................               38.9               13.6              268.3
----------------------------------------------------------------------------------------------------------------
                                                   OBS Surveys
----------------------------------------------------------------------------------------------------------------
PTS SELcum.............................................                 80                  0                0.3
PTS Peak...............................................               38.9               13.6              268.3
----------------------------------------------------------------------------------------------------------------
The largest distance (in bold) of the dual criteria (SELcum or Peak) was used to estimate threshold distances
  and potential takes by Level A harassment.

    Predicted distances to Level A harassment isopleths, which vary 
based on marine mammal hearing groups, were calculated based on 
modeling performed by L-DEO using the Nucleus software program and the 
NMFS user spreadsheet, described below. The acoustic thresholds for 
impulsive sounds (e.g., airguns) contained in the NMFS Technical 
Guidance were presented as dual metric acoustic thresholds using both 
SELcum and peak sound pressure metrics (NMFS 2016a). As dual 
metrics, NMFS considers onset of PTS (Level A harassment) to have 
occurred when either one of the two metrics is exceeded (i.e., metric 
resulting in the largest isopleth). The SELcum metric 
considers both level and duration of exposure, as well as auditory 
weighting functions by marine mammal hearing group. In recognition of 
the fact that the requirement to calculate Level A harassment 
ensonified areas could be more technically challenging to predict due 
to the duration component and the use of weighting functions in the new 
SELcum thresholds, NMFS developed an optional user 
spreadsheet that includes tools to help predict a simple isopleth that 
can be used in conjunction with marine mammal density or occurrence to 
facilitate the estimation of take numbers.
    The SELcum for the 36-airgun array is derived from 
calculating the modified farfield signature. The farfield signature is 
often used as a theoretical representation of the source level. To 
compute the farfield signature, the source level is estimated at a 
large distance (right) below the array (e.g., 9 km), and this level is 
back projected mathematically to a notional distance of 1 m from the 
array's geometrical center. However, it has been recognized that the 
source level from the theoretical farfield signature is never 
physically achieved at the source when the source is an array of 
multiple airguns separated in space (Tolstoy et al., 2009). Near the 
source (at short ranges, distances <1 km), the pulses of sound pressure 
from each individual airgun in the source array do not stack 
constructively as they do for the theoretical farfield signature. The 
pulses from the different airguns spread out in time such that the 
source levels observed or modeled are the result of the summation of 
pulses from a few airguns, not the full array (Tolstoy et al., 2009). 
At larger distances, away from the source array center, sound pressure 
of all the airguns in the array stack coherently, but not within one 
time sample, resulting in smaller source levels (a few dB) than the 
source level derived from the far-field signature. Because the far-
field signature does not take into account the large array effect near 
the source and is calculated as a point source, the far-field signature 
is not an appropriate measure of the sound source level for large 
arrays. See L-DEO's application for further detail on acoustic 
modeling.
    Auditory injury is unlikely to occur for MF cetaceans, given very 
small modeled zones of injury for those species (all estimated zones 
less than 15 m for MF cetaceans), in context of distributed source 
dynamics. The source level of the array is a theoretical definition 
assuming a point source and measurement in the far-field of the source 
(MacGillivray, 2006). As described by Caldwell and Dragoset (2000), an 
array is not a point source, but one that spans a small area. In the 
far-field, individual elements in arrays will effectively work as one 
source because individual pressure peaks will have coalesced into one 
relatively broad pulse. The array can then be considered a ``point 
source.'' For distances within the near-field, i.e., approximately two 
to three times the array dimensions, pressure peaks from individual 
elements do not arrive simultaneously because the observation point is 
not

[[Page 45180]]

equidistant from each element. The effect is destructive interference 
of the outputs of each element, so that peak pressures in the near-
field will be significantly lower than the output of the largest 
individual element. Here, the relevant peak isopleth distances would in 
all cases be expected to be within the near-field of the array where 
the definition of source level breaks down. Therefore, actual locations 
within this distance of the array center where the sound level exceeds 
the relevant peak SPL thresholds would not necessarily exist. In 
general, Caldwell and Dragoset (2000) suggest that the near-field for 
airgun arrays is considered to extend out to approximately 250 m.
    In order to provide quantitative support for this theoretical 
argument, we calculated expected maximum distances at which the near-
field would transition to the far-field (Table 5). For a specific array 
one can estimate the distance at which the near-field transitions to 
the far-field by:
[GRAPHIC] [TIFF OMITTED] TN14JY23.004

    With the condition that D >< [lambda], and where D is the distance, 
L is the longest dimension of the array, and [lambda] is the wavelength 
of the signal (Lurton, 2002). Given that [lambda] can be defined by:
[GRAPHIC] [TIFF OMITTED] TN14JY23.005

where f is the frequency of the sound signal and v is the speed of the 
sound in the medium of interest, one can rewrite the equation for D as:
[GRAPHIC] [TIFF OMITTED] TN14JY23.006

and calculate D directly given a particular frequency and known speed 
of sound (here assumed to be 1,500 m per second in water, although this 
varies with environmental conditions).
    To determine the closest distance to the arrays at which the source 
level predictions in Table 5 are valid (i.e., maximum extent of the 
near-field), we calculated D based on an assumed frequency of 1 kHz. A 
frequency of 1 kHz is commonly used in near-field/far-field 
calculations for airgun arrays (Zykov and Carr, 2014; MacGillivray, 
2006; NSF and USGS, 2011), and based on representative airgun spectrum 
data and field measurements of an airgun array used on the Langseth, 
nearly all (greater than 95 percent) of the energy from airgun arrays 
is below 1 kHz (Tolstoy et al., 2009). Thus, using 1 kHz as the upper 
cut-off for calculating the maximum extent of the near-field should 
reasonably represent the near-field extent in field conditions.
    If the largest distance to the peak sound pressure level threshold 
was equal to or less than the longest dimension of the array (i.e., 
under the array), or within the near-field, then received levels that 
meet or exceed the threshold in most cases are not expected to occur. 
This is because within the near-field and within the dimensions of the 
array, the source levels specified in Appendix A of L-DEO's application 
are overestimated and not applicable. In fact, until one reaches a 
distance of approximately three or four times the near-field distance 
the average intensity of sound at any given distance from the array is 
still less than that based on calculations that assume a directional 
point source (Lurton, 2002). The 6,600-in\3\ airgun array planned for 
use during the survey has an approximate diagonal of 28.8 m, resulting 
in a near-field distance of approximately 138.7 m at 1 kHz (NSF and 
USGS, 2011). Field measurements of this array indicate that the source 
behaves like multiple discrete sources, rather than a directional point 
source, beginning at approximately 400 m (deep site) to 1 km (shallow 
site) from the center of the array (Tolstoy et al., 2009), distances 
that are actually greater than four times the calculated 138.7-m near-
field distance. Within these distances, the recorded received levels 
were always lower than would be predicted based on calculations that 
assume a directional point source, and increasingly so as one moves 
closer towards the array (Tolstoy et al., 2009). Given this, relying on 
the calculated distance (138.7 m) as the distance at which we expect to 
be in the near-field is a conservative approach since even beyond this 
distance the acoustic modeling still overestimates the actual received 
level. Within the near-field, in order to explicitly evaluate the 
likelihood of exceeding any particular acoustic threshold, one would 
need to consider the exact position of the animal, its relationship to 
individual array elements, and how the individual acoustic sources 
propagate and their acoustic fields interact. Given that within the 
near-field and dimensions of the array source levels would be below 
those assumed here, we believe exceedance of the peak pressure 
threshold would only be possible under highly unlikely circumstances.
    In consideration of the received sound levels in the near-field as 
described above, we expect the potential for Level A harassment of MF 
cetaceans to be de minimis, even before the likely moderating effects 
of aversion and/or other compensatory behaviors (e.g., Nachtigall et 
al., 2018) are considered. We do not believe that Level A harassment is 
a likely outcome for any MF cetacean and are not authorizing any take 
by Level A harassment for these species.
    The Level A and Level B harassment estimates are based on a 
consideration of the number of marine mammals that could be within the 
area around the operating airgun array where received levels of sound 
>=160 dB re 1 [micro]Pa RMS are predicted to occur (see Table 1). The 
estimated numbers are based on the densities (numbers per unit area) of 
marine mammals expected to occur in the area in the absence of seismic 
surveys. To the extent that marine mammals tend to move away from 
seismic sources before the sound level reaches the criterion level and 
tend not to approach an operating airgun array, these estimates likely 
overestimate the numbers actually exposed to the specified level of 
sound.

Marine Mammal Occurrence

    In this section we provide information about the occurrence of 
marine mammals, including density or other relevant information which 
will inform the take calculations.
    Habitat-based density models produced by the Duke University Marine 
Geospatial Ecology Laboratory (Roberts et al., 2016; Roberts et al., 
2023) represent the best available information regarding marine mammal 
densities in the survey area. This density information incorporates 
aerial and shipboard line-transect survey data from NMFS and other 
organizations and incorporates data from 8 physiographic and 16 dynamic 
oceanographic and biological covariates, and controls for the influence 
of sea state, group size, availability bias, and perception bias on the 
probability of making a sighting. These density models were originally 
developed for all cetacean taxa in the U.S. Atlantic (Roberts et al., 
2016). In subsequent years, certain models have been updated based on 
additional data as well as certain methodological improvements. More 
information is available online at https://seamap.env.duke.edu/models/Duke/EC/. Marine mammal density estimates in the survey area (animals/
km\2\) were obtained using the most recent model results for all taxa.
    Monthly density grids (e.g., rasters) for each species were 
overlaid with the Survey Area and values from all grid cells that 
overlapped the Survey Area (plus a 40-km buffer) were averaged to 
determine monthly mean density values for each species. Monthly mean 
density values within the survey area were

[[Page 45181]]

averaged for each of the two water depth categories (intermediate and 
deep) for the months May to October. The highest mean monthly density 
estimates for each species were used to estimate take.

Take Estimation

    Here we describe how the information provided above is synthesized 
to produce a quantitative estimate of the take that is reasonably 
likely to occur and authorized. In order to estimate the number of 
marine mammals predicted to be exposed to sound levels that would 
result in Level A or Level B harassment, radial distances from the 
airgun array to the predicted isopleth corresponding to the Level A 
harassment and Level B harassment thresholds are calculated, as 
described above. Those radial distances are then used to calculate the 
area(s) around the airgun array predicted to be ensonified to sound 
levels that exceed the harassment thresholds. The distance for the 160-
dB Level B harassment threshold and PTS (Level A harassment) thresholds 
(based on L-DEO model results) was used to draw a buffer around the 
area expected to be ensonified (i.e., the survey area). The ensonified 
areas were then increased by 25 percent to account for potential 
delays, which is the equivalent to adding 25 percent to the planned 
line km to be surveyed. The highest mean monthly density for each 
species was then multiplied by the daily ensonified areas (increased as 
described above), and then multiplied by the number of survey days (40) 
to estimate potential takes (see Appendix B of L-DEO's application for 
more information).
    L-DEO generally assumed that their estimates of marine mammal 
exposures above harassment thresholds equate to take and requested 
authorization of those takes. Those estimates in turn form the basis 
for our take authorization numbers. For the species for which NMFS does 
not expect there to be a reasonable potential for take by Level A 
harassment to occur, i.e., MF cetaceans, we have added L-DEO's 
estimated exposures above Level A harassment thresholds to their 
estimated exposures above the Level B harassment threshold to produce a 
total number of incidents of take by Level B harassment that is 
authorized. Estimated exposures and take numbers for authorization are 
shown in Table 6. As requested by L-DEO with NMFS concurrence, when 
zero take was calculated we have authorized one group size of take as a 
precaution since the species could potentially occur in the survey 
area.

                                                        Table 6--Estimated Take for Authorization
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                           Estimated take            Authorized take
                 Species                             Stock           ----------------------------------------------------  Abundance \3\    Percent of
                                                                        Level B      Level A      Level B      Level A                         Stock
--------------------------------------------------------------------------------------------------------------------------------------------------------
North Atlantic right whale..............  Western North Atlantic....            0            0            0            0         \4\ 338             n/a
Humpback whale..........................  Gulf of Maine.............            0            0        \1\ 2            0       \6\ 2,259            <0.1
Fin whale...............................  Western North Atlantic....            5            0            5            0       \5\ 3,587             0.1
Sei whale...............................  Nova Scotia...............           28            2           28            2       \5\ 1,043             2.9
Minke whale.............................  Canadian East Coast.......           20            1           20            1       \5\ 4,044             0.5
Blue whale..............................  Western North Atlantic....            2            0            2            0          \6\ 33             6.1
Sperm whale.............................  North Atlantic............          706            3          709            0       \5\ 6,576             9.3
Kogia spp...............................  ..........................          601           50          601           50       \6\ 7,980             8.2
Cuvier's beaked whale...................  Western North Atlantic....          365            1          366            0       \6\ 5,588             6.5
Mesoplodont beaked whales...............  ..........................          154            1          155            0       \6\ 6,526             2.4
Pilot whales............................  ..........................        1,424            4        1,428            0      \6\ 23,905               6
Rough-toothed dolphin...................  Western North Atlantic....          301            1          302            0       \6\ 1,011              30
Bottlenose dolphin......................  Western North Atlantic            4,445           12        4,457            0      \5\ 68,739             6.5
                                           Offshore.
Pantropical spotted dolphin.............  Western North Atlantic....          419            1          420            0       \6\ 1,403              30
Atlantic spotted dolphin................  Western North Atlantic....        1,768            6        1,774            0      \5\ 39,352             4.5
Spinner dolphin.........................  Western North Atlantic....          149            0          149            0         \6\ 885            16.8
Clymene dolphin.........................  Western North Atlantic....            0            0      \2\ 182            0       \6\ 8,576             2.1
Striped dolphin.........................  Western North Atlantic....            0            0       \1\ 46            0      \6\ 54,707            <0.1
Fraser's dolphin........................  Western North Atlantic....          226            1          227            0         \6\ 658            34.5
Risso's dolphin.........................  Western North Atlantic....        1,277            3        1,280            0      \5\ 24,260             5.3
Common dolphin..........................  Western North Atlantic....          181            1          182            0     \5\ 144,036             0.1
Melon-headed whale......................  Western North Atlantic....          212            1          213            0         \6\ 618            34.5
Pygmy killer whale......................  Western North Atlantic....           20            0           20            0          \6\ 68            29.4
False killer whale......................  Western North Atlantic....            4            0        \2\ 6            0         \6\ 139             4.3
Killer whale............................  Western North Atlantic....            6            0            6            0          \6\ 73             8.2
Harbor porpoise.........................  Gulf of Maine/Bay of Fundy            0            0        \1\ 3            0      \5\ 55,049            <0.1
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ Take increased to mean group size from AMAPPS (Palka et al., 2017 and 2021).
\2\ Take increased to mean group size from Ocean Biogeographic Information System (OBIS) (2023).
\3\ Modeled abundance (Roberts et al., 2023) used unless noted.
\4\ Abundance from draft 2022 U.S, Atlantic and Gulf of Mexico Marine Mammal SARs.
\5\ Averaged monthly (May-Oct) abundance.
\6\ Only single annual abundance given.

Mitigation

    In order to issue an IHA under section 101(a)(5)(D) of the MMPA, 
NMFS must set forth the permissible methods of taking pursuant to the 
activity, and other means of effecting the least practicable impact on 
the species or stock and its habitat, paying particular attention to 
rookeries, mating grounds, and areas of similar significance, and on 
the availability of the species or stock for taking for certain 
subsistence uses (latter not applicable for this action). NMFS 
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 the 
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)).
    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, the successful 
implementation of the measure(s) is expected to reduce impacts to 
marine mammals, marine mammal species or

[[Page 45182]]

stocks, and their habitat. This considers the nature of the potential 
adverse impact being mitigated (likelihood, scope, range). It further 
considers the likelihood that the measure will be effective if 
implemented (probability of accomplishing the mitigating result if 
implemented as planned), the likelihood of effective implementation 
(probability implemented as planned), and;
    (2) The practicability of the measures for applicant 
implementation, which may consider such things as cost, and impact on 
operations.

Vessel-Based Visual Mitigation Monitoring

    Visual monitoring requires the use of trained observers (herein 
referred to as visual protected species observers (PSO)) to scan the 
ocean surface for the presence of marine mammals. The area to be 
scanned visually includes primarily the shutdown zone (SZ), within 
which observation of certain marine mammals requires shutdown of the 
acoustic source, but also a buffer zone and, to the extent possible 
depending on conditions, the surrounding waters. The buffer zone means 
an area beyond the SZ to be monitored for the presence of marine 
mammals that may enter the SZ. During pre-start clearance monitoring 
(i.e., before ramp-up begins), the buffer zone also acts as an 
extension of the SZ in that observations of marine mammals within the 
buffer zone would also prevent airgun operations from beginning (i.e., 
ramp-up). The buffer zone encompasses the area at and below the sea 
surface from the edge of the 0-500 m SZ, out to a radius of 1,000 m 
from the edges of the airgun array (500-1,000 m). This 1,000-m zone (SZ 
plus buffer) represents the pre-start clearance zone. Visual monitoring 
of the SZ and adjacent waters is intended to establish and, when visual 
conditions allow, maintain zones around the sound source that are clear 
of marine mammals, thereby reducing or eliminating the potential for 
injury and minimizing the potential for more severe behavioral 
reactions for animals occurring closer to the vessel. Visual monitoring 
of the buffer zone is intended to (1) provide additional protection to 
marine mammals that may be in the vicinity of the vessel during pre-
start clearance, and (2) during airgun use, aid in establishing and 
maintaining the SZ by alerting the visual observer and crew of marine 
mammals that are outside of, but may approach and enter, the SZ.
    L-DEO must use dedicated, trained, and NMFS-approved PSOs. The PSOs 
must have no tasks other than to conduct observational effort, record 
observational data, and communicate with and instruct relevant vessel 
crew with regard to the presence of marine mammals and mitigation 
requirements. PSO resumes shall be provided to NMFS for approval.
    At least one of the visual and two of the acoustic PSOs (discussed 
below) aboard the vessel must have a minimum of 90 days at-sea 
experience working in those roles, respectively, with no more than 18 
months elapsed since the conclusion of the at-sea experience. One 
visual PSO with such experience shall be designated as the lead for the 
entire protected species observation team. The lead PSO shall serve as 
primary point of contact for the vessel operator and ensure all PSO 
requirements per the IHA are met. To the maximum extent practicable, 
the experienced PSOs should be scheduled to be on duty with those PSOs 
with appropriate training but who have not yet gained relevant 
experience.
    During survey operations (e.g., any day on which use of the airgun 
array is planned to occur, and whenever the airgun array is in the 
water, whether activated or not), a minimum of two visual PSOs must be 
on duty and conducting visual observations at all times during daylight 
hours (i.e., from 30 minutes prior to sunrise through 30 minutes 
following sunset). Visual monitoring of the pre-start clearance zone 
must begin no less than 30 minutes prior to ramp-up, and monitoring 
must continue until 1 hour after use of the airgun array ceases or 
until 30 minutes past sunset. Visual PSOs shall coordinate to ensure 
360[deg] visual coverage around the vessel from the most appropriate 
observation posts, and shall conduct visual observations using 
binoculars and the naked eye while free from distractions and in a 
consistent, systematic, and diligent manner.
    PSOs shall establish and monitor the shutdown and buffer zones. 
These zones shall be based upon the radial distance from the edges of 
the airgun array (rather than being based on the center of the array or 
around the vessel itself). During use of the airgun array (i.e., 
anytime airguns are active, including ramp-up), detections of marine 
mammals within the buffer zone (but outside the SZ) shall be 
communicated to the operator to prepare for the potential shutdown of 
the airgun array. Visual PSOs will immediately communicate all 
observations to the on duty acoustic PSO(s), including any 
determination by the PSO regarding species identification, distance, 
and bearing and the degree of confidence in the determination. Any 
observations of marine mammals by crew members shall be relayed to the 
PSO team. During good conditions (e.g., daylight hours; Beaufort sea 
state (BSS) 3 or less), visual PSOs shall conduct observations when the 
airgun array is not operating for comparison of sighting rates and 
behavior with and without use of the airgun array and between 
acquisition periods, to the maximum extent practicable.
    Visual PSOs may be on watch for a maximum of 4 consecutive hours 
followed by a break of at least 1 hour between watches and may conduct 
a maximum of 12 hours of observation per 24-hour period. Combined 
observational duties (visual and acoustic but not at same time) may not 
exceed 12 hours per 24-hour period for any individual PSO.

Passive Acoustic Monitoring

    Passive acoustic monitoring (PAM) means the use of trained 
personnel (sometimes referred to as PAM operators, herein referred to 
as acoustic PSOs) to operate PAM equipment to acoustically detect the 
presence of marine mammals. Acoustic monitoring involves acoustically 
detecting marine mammals regardless of distance from the source, as 
localization of animals may not always be possible. Acoustic monitoring 
is intended to further support visual monitoring (during daylight 
hours) in maintaining an SZ around the sound source that is clear of 
marine mammals. In cases where visual monitoring is not effective 
(e.g., due to weather, nighttime), acoustic monitoring may be used to 
allow certain activities to occur, as further detailed below.
    PAM would take place in addition to the visual monitoring program. 
Visual monitoring typically is not effective during periods of poor 
visibility or at night, and even with good visibility, is unable to 
detect marine mammals when they are below the surface or beyond visual 
range. Acoustic monitoring can be used in addition to visual 
observations to improve detection, identification, and localization of 
cetaceans. The acoustic monitoring would serve to alert visual PSOs (if 
on duty) when vocalizing cetaceans are detected. It is only useful when 
marine mammals vocalize, but it can be effective either by day or by 
night, and does not depend on good visibility. It would be monitored in 
real time so that the visual observers can be advised when cetaceans 
are detected.
    The R/V Langseth will use a towed PAM system, which must be 
monitored by at a minimum one on duty acoustic PSO beginning at least 
30 minutes prior to ramp-up and at all times during use

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of the airgun array. Acoustic PSOs may be on watch for a maximum of 4 
consecutive hours followed by a break of at least 1 hour between 
watches and may conduct a maximum of 12 hours of observation per 24-
hour period. Combined observational duties (acoustic and visual but not 
at same time) may not exceed 12 hours per 24-hour period for any 
individual PSO.
    Survey activity may continue for 30 minutes when the PAM system 
malfunctions or is damaged, while the acoustic PSO diagnoses the issue. 
If the diagnosis indicates that the PAM system must be repaired to 
solve the problem, operations may continue for an additional 10 hours 
without acoustic monitoring during daylight hours only under the 
following conditions:
     Sea state is less than or equal to BSS 4;
     No marine mammals (excluding delphinids) detected solely 
by PAM in the applicable SZ in the previous 2 hours;
     NMFS is notified via email as soon as practicable with the 
time and location in which operations began occurring without an active 
PAM system; and
     Operations with an active airgun array, but without an 
operating PAM system, do not exceed a cumulative total of 10 hours in 
any 24-hour period.

Establishment of Shutdown and Pre-Start Clearance Zones

    An SZ is a defined area within which occurrence of a marine mammal 
triggers mitigation action intended to reduce the potential for certain 
outcomes, e.g., auditory injury, disruption of critical behaviors. The 
PSOs would establish a minimum SZ with a 500-m radius. The 500-m SZ 
would be based on radial distance from the edge of the airgun array 
(rather than being based on the center of the array or around the 
vessel itself). With certain exceptions (described below), if a marine 
mammal appears within or enters this zone, the airgun array would be 
shut down.
    The pre-start clearance zone is defined as the area that must be 
clear of marine mammals prior to beginning ramp-up of the airgun array, 
and includes the SZ plus the buffer zone. Detections of marine mammals 
within the pre-start clearance zone would prevent airgun operations 
from beginning (i.e., ramp-up).
    The 500-m SZ is intended to be precautionary in the sense that it 
would be expected to contain sound exceeding the injury criteria for 
all cetacean hearing groups, (based on the dual criteria of 
SELcum and peak SPL), while also providing a consistent, 
reasonably observable zone within which PSOs would typically be able to 
conduct effective observational effort. Additionally, a 500-m SZ is 
expected to minimize the likelihood that marine mammals will be exposed 
to levels likely to result in more severe behavioral responses. 
Although significantly greater distances may be observed from an 
elevated platform under good conditions, we believe that 500 m is 
likely regularly attainable for PSOs using the naked eye during typical 
conditions. The pre-start clearance zone simply represents the addition 
of a buffer to the SZ, doubling the SZ size during pre-clearance.
    An extended SZ of 1,500 m must be enforced for all beaked whales 
and Kogia species. No buffer of this extended SZ is required, as NMFS 
concludes that this extended SZ is sufficiently protective to mitigate 
harassment to beaked whales and Kogia species.

Pre-Start Clearance and Ramp-Up

    Ramp-up (sometimes referred to as ``soft start'') means the gradual 
and systematic increase of emitted sound levels from an airgun array. 
Ramp-up begins by first activating a single airgun of the smallest 
volume, followed by doubling the number of active elements in stages 
until the full complement of an array's airguns are active. Each stage 
should be approximately the same duration, and the total duration 
should not be less than approximately 20 minutes. The intent of pre-
start clearance observation (30 minutes) is to ensure no marine mammals 
are observed within the pre-start clearance zone (or extended SZ, for 
beaked whales and Kogia spp.) prior to the beginning of ramp-up. During 
the pre-start clearance period is the only time observations of marine 
mammals in the buffer zone would prevent operations (i.e., the 
beginning of ramp-up). The intent of ramp-up is to warn marine mammals 
of pending seismic survey operations and to allow sufficient time for 
those animals to leave the immediate vicinity prior to the sound source 
reaching full intensity. A ramp-up procedure, involving a step-wise 
increase in the number of airguns firing and total array volume until 
all operational airguns are activated and the full volume is achieved, 
is required at all times as part of the activation of the airgun array. 
All operators must adhere to the following pre-start clearance and 
ramp-up requirements:
     The operator must notify a designated PSO of the planned 
start of ramp-up as agreed upon with the lead PSO; the notification 
time should not be less than 60 minutes prior to the planned ramp-up in 
order to allow the PSOs time to monitor the pre-start clearance zone 
(and extended SZ) for 30 minutes prior to the initiation of ramp-up 
(pre-start clearance);
     Ramp-ups shall be scheduled so as to minimize the time 
spent with the source activated prior to reaching the designated run-
in;
     One of the PSOs conducting pre-start clearance 
observations must be notified again immediately prior to initiating 
ramp-up procedures and the operator must receive confirmation from the 
PSO to proceed;
     Ramp-up may not be initiated if any marine mammal is 
within the applicable shutdown or buffer zone. If a marine mammal is 
observed within the pre-start clearance zone (or extended SZ, for 
beaked whales and Kogia species) during the 30 minute pre-start 
clearance period, ramp-up may not begin until the animal(s) has been 
observed exiting the zones or until an additional time period has 
elapsed with no further sightings (15 minutes for small odontocetes, 
and 30 minutes for all mysticetes and all other odontocetes, including 
sperm whales, beaked whales, and large delphinids, such as pilot 
whales);
     Ramp-up shall begin by activating a single airgun of the 
smallest volume in the array and shall continue in stages by doubling 
the number of active elements at the commencement of each stage, with 
each stage of approximately the same duration. Duration shall not be 
less than 20 minutes. The operator must provide information to the PSO 
documenting that appropriate procedures were followed;
     PSOs must monitor the pre-start clearance zone (and 
extended SZ) during ramp-up, and ramp-up must cease and the source must 
be shut down upon detection of a marine mammal within the applicable 
zone. Once ramp-up has begun, detections of marine mammals within the 
buffer zone do not require shutdown, but such observation shall be 
communicated to the operator to prepare for the potential shutdown;
     Ramp-up may occur at times of poor visibility, including 
nighttime, if appropriate acoustic monitoring has occurred with no 
detections in the 30 minutes prior to beginning ramp-up. Airgun array 
activation may only occur at times of poor visibility where operational 
planning cannot reasonably avoid such circumstances;
     If the airgun array is shut down for brief periods (i.e., 
less than 30 minutes) for reasons other than implementation of 
prescribed mitigation (e.g., mechanical difficulty), it may be 
activated again without ramp-up if PSOs

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have maintained constant visual and/or acoustic observation and no 
visual or acoustic detections of marine mammals have occurred within 
the pre-start clearance zone (or extended SZ, where applicable). For 
any longer shutdown, pre-start clearance observation and ramp-up are 
required.; and
     Testing of the airgun array involving all elements 
requires ramp-up. Testing limited to individual source elements or 
strings does not require ramp-up but does require pre-start clearance 
of 30 minutes.

Shutdown

    The shutdown of an airgun array requires the immediate de-
activation of all individual airgun elements of the array. Any PSO on 
duty will have the authority to delay the start of survey operations or 
to call for shutdown of the airgun array if a marine mammal is detected 
within the applicable SZ. The operator must also establish and maintain 
clear lines of communication directly between PSOs on duty and crew 
controlling the airgun array to ensure that shutdown commands are 
conveyed swiftly while allowing PSOs to maintain watch. When both 
visual and acoustic PSOs are on duty, all detections will be 
immediately communicated to the remainder of the on-duty PSO team for 
potential verification of visual observations by the acoustic PSO or of 
acoustic detections by visual PSOs. When the airgun array is active 
(i.e., anytime one or more airguns is active, including during ramp-up) 
and (1) a marine mammal appears within or enters the applicable SZ and/
or (2) a marine mammal (other than delphinids, see below) is detected 
acoustically and localized within the applicable SZ, the airgun array 
will be shut down. When shutdown is called for by a PSO, the airgun 
array will be immediately deactivated and any dispute resolved only 
following deactivation. Additionally, shutdown will occur whenever PAM 
alone (without visual sighting), confirms presence of marine mammal(s) 
in the SZ. If the acoustic PSO cannot confirm presence within the SZ, 
visual PSOs will be notified but shutdown is not required.
    Following a shutdown, airgun activity would not resume until the 
marine mammal has cleared the SZ. The animal would be considered to 
have cleared the SZ if it is visually observed to have departed the SZ 
(i.e., animal is not required to fully exit the buffer zone where 
applicable), or it has not been seen within the SZ for 15 minutes for 
small odontocetes, or 30 minutes for all mysticetes and all other 
odontocetes, including sperm whales, beaked whales, Kogia species, and 
large delphinids, such as pilot whales.
    The shutdown requirement is waived for small dolphins if an 
individual is detected within the SZ. As defined here, the small 
dolphin group is intended to encompass those members of the Family 
Delphinidae most likely to voluntarily approach the source vessel for 
purposes of interacting with the vessel and/or airgun array (e.g., bow 
riding). This exception to the shutdown requirement applies solely to 
specific genera of small dolphins (Delphinus, Lagenodelphis, Stenella, 
Steno, and Tursiops).
    We include this small dolphin exception because shutdown 
requirements for small dolphins under all circumstances represent 
practicability concerns without likely commensurate benefits for the 
animals in question. Small dolphins are generally the most commonly 
observed marine mammals in the specific geographic region and would 
typically be the only marine mammals likely to intentionally approach 
the vessel. As described above, auditory injury is extremely unlikely 
to occur for MF cetaceans (e.g., delphinids), as this group is 
relatively insensitive to sound produced at the predominant frequencies 
in an airgun pulse while also having a relatively high threshold for 
the onset of auditory injury (i.e., permanent threshold shift).
    A large body of anecdotal evidence indicates that small dolphins 
commonly approach vessels and/or towed arrays during active sound 
production for purposes of bow riding, with no apparent effect observed 
(e.g., Barkaszi et al., 2012; Barkaszi and Kelly, 2018). The potential 
for increased shutdowns resulting from such a measure would require the 
Langseth to revisit the missed track line to reacquire data, resulting 
in an overall increase in the total sound energy input to the marine 
environment and an increase in the total duration over which the survey 
is active in a given area. Although other MF hearing specialists (e.g., 
large delphinids) are no more likely to incur auditory injury than are 
small dolphins, they are much less likely to approach vessels. 
Therefore, retaining a shutdown requirement for large delphinids would 
not have similar impacts in terms of either practicability for the 
applicant or corollary increase in sound energy output and time on the 
water. We do anticipate some benefit for a shutdown requirement for 
large delphinids in that it simplifies somewhat the total range of 
decision-making for PSOs and may preclude any potential for 
physiological effects other than to the auditory system as well as some 
more severe behavioral reactions for any such animals in close 
proximity to the Langseth.
    Visual PSOs shall use best professional judgment in making the 
decision to call for a shutdown if there is uncertainty regarding 
identification (i.e., whether the observed marine mammal(s) belongs to 
one of the delphinid genera for which shutdown is waived or one of the 
species with a larger SZ).
    L-DEO must implement shutdown if a marine mammal species for which 
take was not authorized, or a species for which authorization was 
granted but the authorized takes have been met, approaches the Level A 
or Level B harassment zones. L-DEO must also implement shutdown if any 
large whale (defined as a sperm whale or any mysticete species) with a 
calf (defined as an animal less than two-thirds the body size of an 
adult observed to be in close association with an adult) and/or an 
aggregation of six or more large whales are observed at any distance. 
Finally, L-DEO must implement shutdown upon detection (visual or 
acoustic) of a North Atlantic right whale at any distance.

Vessel Strike Avoidance

    Vessel personnel should use an appropriate reference guide that 
includes identifying information on all marine mammals that may be 
encountered. Vessel operators must comply with the below measures 
except under extraordinary circumstances when the safety of the vessel 
or crew is in doubt or the safety of life at sea is in question. These 
requirements do not apply in any case where compliance would create an 
imminent and serious threat to a person or vessel or to the extent that 
a vessel is restricted in its ability to maneuver and, because of the 
restriction, cannot comply.
    Vessel operators and crews must maintain a vigilant watch for all 
marine mammals and slow down, stop their vessel, or alter course, as 
appropriate and regardless of vessel size, to avoid striking any marine 
mammal. A single marine mammal at the surface may indicate the presence 
of submerged animals in the vicinity of the vessel; therefore, 
precautionary measures should always be exercised. A visual observer 
aboard the vessel must monitor a vessel strike avoidance zone around 
the vessel (distances stated below). Visual observers monitoring the 
vessel strike avoidance zone may be third-party observers (i.e., PSOs) 
or crew members, but crew members responsible for these duties must be 
provided sufficient training to (1)

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distinguish marine mammals from other phenomena and (2) broadly to 
identify a marine mammal as a right whale, other whale (defined in this 
context as sperm whales or baleen whales other than right whales), or 
other marine mammals.
    All vessels, regardless of size, must observe a 10-knot speed 
restriction in specific areas designated by NMFS for the protection of 
North Atlantic right whales from vessel strikes. These include all 
Seasonal Management Areas (SMA) (when in effect) and any dynamic 
management areas (DMA) (when in effect). See www.fisheries.noaa.gov/national/endangered-species-conservation/reducing-ship-strikes-north-atlantic-right-whales for specific detail regarding these areas.
    Vessel speeds must be reduced to 10 kn or less when mother/calf 
pairs, pods, or large assemblages of cetaceans are observed near a 
vessel.
    All vessels must maintain a minimum separation distance of 500 m 
from right whales. If a right whale is sighted within the relevant 
separation distance, the vessel must steer a course away at 10 knots or 
less until the 500-m separation distance has been established. If a 
whale is observed but cannot be confirmed as a species other than a 
right whale, the vessel operator must assume that it is a right whale 
and take appropriate action.
    All vessels must maintain a minimum separation distance of 100 m 
from sperm whales and all other baleen whales.
    All vessels must, to the maximum extent practicable, attempt to 
maintain a minimum separation distance of 50 m from all other marine 
mammals, with an understanding that at times this may not be possible 
(e.g., for animals that approach the vessel).
    When marine mammals are sighted while a vessel is underway, the 
vessel shall take action as necessary to avoid violating the relevant 
separation distance (e.g., attempt to remain parallel to the animal's 
course, avoid excessive speed or abrupt changes in direction until the 
animal has left the area). If marine mammals are sighted within the 
relevant separation distance, the vessel must reduce speed and shift 
the engine to neutral, not engaging the engines until animals are clear 
of the area. This does not apply to any vessel towing gear or any 
vessel that is navigationally constrained.

Operational Restrictions

    L-DEO must limit airgun use to between May 1 and October 31. Vessel 
movement and other activities that do not require use of airguns may 
occur outside of these dates. If any activities (non-seismic) are 
conducted between November 1 and April 30, L-DEO must submit daily 
observations to the NMFS Southeast Regional Office (SERO). L-DEO must 
also notify SERO on the start and end date of seismic operations in the 
survey area via email at [email protected].
    To further prevent exposure of North Atlantic right whales during a 
time when they may start to migrate to calving and nursing grounds in 
coastal and shelf waters adjacent to the survey area, the L-DEO must 
not conduct seismic survey activities in the nearshore portions (i.e., 
survey tracklines) of the action area on or after October 1 through 
April 30. We define ``nearshore lines'' as those within 100 km of the 
U.S. shore in areas north of 31[deg] N and within 80 km from the U.S. 
shore in areas south of 31[deg] N. Relative to the survey area, these 
nearshore portions of the survey area overlap with higher density areas 
for North Atlantic right whale during the month of October as shown in 
Roberts et al. (2023).
    Based on our evaluation of the applicant's measures, as well as 
other measures considered by NMFS, NMFS has determined that the 
mitigation measures provide the means of effecting the least 
practicable impact on the affected species or stocks and their habitat, 
paying particular attention to rookeries, mating grounds, and areas of 
similar significance.

Monitoring and Reporting

    In order to issue an IHA for an activity, section 101(a)(5)(D) of 
the MMPA states that NMFS must set forth requirements pertaining to the 
monitoring and reporting of such taking. The MMPA implementing 
regulations at 50 CFR 216.104(a)(13) indicate that requests for 
authorizations must include the suggested means of accomplishing the 
necessary monitoring and reporting that will result in increased 
knowledge of the species and of the level of taking or impacts on 
populations of marine mammals that are expected to be present while 
conducting the activities. Effective reporting is critical both to 
compliance as well as ensuring that the most value is obtained from the 
required monitoring.
    Monitoring and reporting requirements prescribed by NMFS should 
contribute to improved understanding of one or more of the following:
     Occurrence of marine mammal species or stocks in the area 
in which take is anticipated (e.g., presence, abundance, distribution, 
density);
     Nature, scope, or context of likely marine mammal exposure 
to potential stressors/impacts (individual or cumulative, acute or 
chronic), through better understanding of: (1) action or environment 
(e.g., source characterization, propagation, ambient noise); (2) 
affected species (e.g., life history, dive patterns); (3) co-occurrence 
of marine mammal species with the activity; or (4) biological or 
behavioral context of exposure (e.g., age, calving or feeding areas);
     Individual marine mammal responses (behavioral or 
physiological) to acoustic stressors (acute, chronic, or cumulative), 
other stressors, or cumulative impacts from multiple stressors;
     How anticipated responses to stressors impact either: (1) 
long-term fitness and survival of individual marine mammals; or (2) 
populations, species, or stocks;
     Effects on marine mammal habitat (e.g., marine mammal prey 
species, acoustic habitat, or other important physical components of 
marine mammal habitat); and
     Mitigation and monitoring effectiveness.

Vessel-Based Visual Monitoring

    As described above, PSO observations would take place during 
daytime airgun operations. During seismic survey operations, at least 
five visual PSOs would be based aboard the Langseth. Two visual PSOs 
would be on duty at all times during daytime hours. Monitoring shall be 
conducted in accordance with the following requirements:
     The operator shall provide PSOs with bigeye binoculars 
(e.g., 25 x 150; 2.7 view angle; individual ocular focus; height 
control) of appropriate quality solely for PSO use. These shall be 
pedestal-mounted on the deck at the most appropriate vantage point that 
provides for optimal sea surface observation, PSO safety, and safe 
operation of the vessel; and
     The operator will work with the selected third-party 
observer provider to ensure PSOs have all equipment (including backup 
equipment) needed to adequately perform necessary tasks, including 
accurate determination of distance and bearing to observed marine 
mammals.
    PSOs must have the following requirements and qualifications:
     PSOs shall be independent, dedicated, trained visual and 
acoustic PSOs and must be employed by a third-party observer provider;

[[Page 45186]]

     PSOs shall have no tasks other than to conduct 
observational effort (visual or acoustic), collect data, and 
communicate with and instruct relevant vessel crew with regard to the 
presence of protected species and mitigation requirements (including 
brief alerts regarding maritime hazards);
     PSOs shall have successfully completed an approved PSO 
training course appropriate for their designated task (visual or 
acoustic). Acoustic PSOs are required to complete specialized training 
for operating PAM systems and are encouraged to have familiarity with 
the vessel with which they will be working;
     PSOs can act as acoustic or visual observers (but not at 
the same time) as long as they demonstrate that their training and 
experience are sufficient to perform the task at hand;
     NMFS must review and approve PSO resumes accompanied by a 
relevant training course information packet that includes the name and 
qualifications (i.e., experience, training completed, or educational 
background) of the instructor(s), the course outline or syllabus, and 
course reference material as well as a document stating successful 
completion of the course;
     PSOs must successfully complete relevant training, 
including completion of all required coursework and passing (80 percent 
or greater) a written and/or oral examination developed for the 
training program;
     PSOs must have successfully attained a bachelor's degree 
from an accredited college or university with a major in one of the 
natural sciences, a minimum of 30 semester hours or equivalent in the 
biological sciences, and at least one undergraduate course in math or 
statistics; and
     The educational requirements may be waived if the PSO has 
acquired the relevant skills through alternate experience. Requests for 
such a waiver shall be submitted to NMFS and must include written 
justification. Requests shall be granted or denied (with justification) 
by NMFS within 1 week of receipt of submitted information. Alternate 
experience that may be considered includes, but is not limited to: (1) 
secondary education and/or experience comparable to PSO duties; (2) 
previous work experience conducting academic, commercial, or 
government-sponsored protected species surveys; or (3) previous work 
experience as a PSO; the PSO should demonstrate good standing and 
consistently good performance of PSO duties.
     For data collection purposes, PSOs shall use standardized 
electronic data collection forms. PSOs shall record detailed 
information about any implementation of mitigation requirements, 
including the distance of animals to the airgun array and description 
of specific actions that ensued, the behavior of the animal(s), any 
observed changes in behavior before and after implementation of 
mitigation, and if shutdown was implemented, the length of time before 
any subsequent ramp-up of the airgun array. If required mitigation was 
not implemented, PSOs should record a description of the circumstances. 
At a minimum, the following information must be recorded:
     Vessel name, vessel size and type, maximum speed 
capability of vessel;
     Dates (MM/DD/YYYY) of departures and returns to port with 
port name;
     PSO names and affiliations, PSO ID (initials or other 
identifier);
     Date (MM/DD/YYYY) and participants of PSO briefings;
     Visual monitoring equipment used (description);
     PSO location on vessel and height (meters) of observation 
location above water surface;
     Watch status (description);
     Dates (MM/DD/YYYY) and times (Greenwich Mean Time/UTC) of 
survey on/off effort and times (GMC/UTC) corresponding with PSO on/off 
effort;
     Vessel location (decimal degrees) when survey effort began 
and ended and vessel location at beginning and end of visual PSO duty 
shifts;
     Vessel location (decimal degrees) at 30-second intervals 
if obtainable from data collection software, otherwise at practical 
regular interval;
     Vessel heading (compass heading) and speed (knots) at 
beginning and end of visual PSO duty shifts and upon any change;
     Water depth (meters) (if obtainable from data collection 
software);
     Environmental conditions while on visual survey (at 
beginning and end of PSO shift and whenever conditions changed 
significantly), including BSS and any other relevant weather conditions 
including cloud cover, fog, sun glare, and overall visibility to the 
horizon;
     Factors that may have contributed to impaired observations 
during each PSO shift change or as needed as environmental conditions 
changed (description) (e.g., vessel traffic, equipment malfunctions); 
and
     Vessel/Survey activity information (and changes thereof) 
(description), such as airgun power output while in operation, number 
and volume of airguns operating in the array, tow depth of the array, 
and any other notes of significance (i.e., pre-start clearance, ramp-
up, shutdown, testing, shooting, ramp-up completion, end of operations, 
streamers, etc.).
     Upon visual observation of any marine mammals, the 
following information must be recorded:
     Sighting ID (numeric);
     Watch status (sighting made by PSO on/off effort, 
opportunistic, crew, alternate vessel/platform);
     Location of PSO/observer (description);
     Vessel activity at the time of the sighting (e.g., 
deploying, recovering, testing, shooting, data acquisition, other);
     PSO who sighted the animal/ID;
     Time/date of sighting (GMT/UTC, MM/DD/YYYY);
     Initial detection method (description);
     Sighting cue (description);
     Vessel location at time of sighting (decimal degrees);
     Water depth (meters);
     Direction of vessel's travel (compass direction);
     Speed (knots) of the vessel from which the observation was 
made;
     Direction of animal's travel relative to the vessel 
(description, compass heading);
     Bearing to sighting (degrees);
     Identification of the animal (e.g., genus/species, lowest 
possible taxonomic level, or unidentified) and the composition of the 
group if there is a mix of species;
     Species reliability (an indicator of confidence in 
identification) (1 = unsure/possible, 2 = probable, 3 = definite/sure, 
9 = unknown/not recorded);
     Estimated distance to the animal (meters) and method of 
estimating distance;
     Estimated number of animals (high/low/best) (numeric);
     Estimated number of animals by cohort (adults, yearlings, 
juveniles, calves, group composition, etc.);
     Description (as many distinguishing features as possible 
of each individual seen, including length, shape, color, pattern, scars 
or markings, shape and size of dorsal fin, shape of head, and blow 
characteristics);
     Detailed behavior observations (e.g., number of blows/
breaths, number of surfaces, breaching, spyhopping, diving, feeding, 
traveling; as explicit and detailed as possible; note any observed 
changes in behavior);
     Animal's closest point of approach (meters) and/or closest 
distance from any element of the airgun array;
     Description of any actions implemented in response to the 
sighting

[[Page 45187]]

(e.g., delays, shutdown, ramp-up) and time and location of the action.
     Photos (Yes/No);
     Photo Frame Numbers (List of numbers); and
     Conditions at time of sighting (Visibility; Beaufort Sea 
State);
    If a marine mammal is detected while using the PAM system, the 
following information should be recorded:
     An acoustic encounter identification number, and whether 
the detection was linked with a visual sighting;
     Date and time when first and last heard;
     Types and nature of sounds heard (e.g., clicks, whistles, 
creaks, burst pulses, continuous, sporadic, strength of signal); and
     Any additional information recorded such as water depth of 
the hydrophone array, bearing of the animal to the vessel (if 
determinable), species or taxonomic group (if determinable), 
spectrogram screenshot, and any other notable information.

Reporting

    The Holder shall submit a draft comprehensive report on all 
activities and monitoring results within 90 days of the completion of 
the survey or expiration of the IHA, whichever comes sooner. The report 
must describe all activities conducted and sightings of marine mammals, 
must provide full documentation of methods, results, and interpretation 
pertaining to all monitoring, and must summarize the dates and 
locations of survey operations and all marine mammal sightings (dates, 
times, locations, activities, associated survey activities). The draft 
report shall also include geo-referenced time-stamped vessel tracklines 
for all time periods during which airgun arrays were operating. 
Tracklines should include points recording any change in airgun array 
status (e.g., when the sources began operating, when they were turned 
off, or when they changed operational status such as from full array to 
single gun or vice versa). GIS files shall be provided in ESRI 
shapefile format and include the UTC date and time, latitude in decimal 
degrees, and longitude in decimal degrees. All coordinates shall be 
referenced to the WGS84 geographic coordinate system. In addition to 
the report, all raw observational data shall be made available. The 
report must summarize data collected as described above in ``Data 
Collection.'' A final report must be submitted within 30 days following 
resolution of any comments on the draft report.
    The report must include a validation document concerning the use of 
PAM, which should include necessary noise validation diagrams and 
demonstrate whether background noise levels on the PAM deployment 
limited achievement of the planned detection goals. Copies of any 
vessel self-noise assessment reports must be included with the report.

Reporting NARW

    Although not anticipated, if a North Atlantic right whale is 
observed at any time by PSOs or personnel on any project vessels, 
during surveys or during vessel transit, L-DEO must immediately report 
sighting information to the NMFS North Atlantic Right Whale Sighting 
Advisory System: 877-WHALE-HELP (877-942-5343). North Atlantic right 
whale sightings in any location must also be reported to the U.S. Coast 
Guard via channel 16.

Reporting Injured or Dead Marine Mammals

    Discovery of injured or dead marine mammals--In the event that 
personnel involved in the survey activities discover an injured or dead 
marine mammal, the L-DEO shall report the incident to the OPR, NMFS, 
and to the NMFS Southeast Regional Stranding Coordinator as soon as 
feasible. The report must include the following information:
     Time, date, and location (latitude/longitude) of the first 
discovery (and updated location information if known and applicable);
     Species identification (if known) or description of the 
animal(s) involved;
     Condition of the animal(s) (including carcass condition if 
the animal is dead);
     Observed behaviors of the animal(s), if alive;
     If available, photographs or video footage of the 
animal(s); and
     General circumstances under which the animal was 
discovered.
    Vessel strike--In the event of a strike of a marine mammal by any 
vessel involved in the activities covered by the authorization, L-DEO 
shall report the incident to OPR, NMFS, and to the NMFS Southeast 
Regional Stranding Coordinator as soon as feasible. The report must 
include the following information:
     Time, date, and location (latitude/longitude) of the 
incident;
     Vessel's speed during and leading up to the incident;
     Vessel's course/heading and what operations were being 
conducted (if applicable);
     Status of all sound sources in use;
     Description of avoidance measures/requirements that were 
in place at the time of the strike and what additional measure were 
taken, if any, to avoid strike;
     Environmental conditions (e.g., wind speed and direction, 
BSS, cloud cover, visibility) immediately preceding the strike;
     Species identification (if known) or description of the 
animal(s) involved;
     Estimated size and length of the animal that was struck;
     Description of the behavior of the marine mammal 
immediately preceding and following the strike;
     If available, description of the presence and behavior of 
any other marine mammals present immediately preceding the strike;
     Estimated fate of the animal (e.g., dead, injured but 
alive, injured and moving, blood or tissue observed in the water, 
status unknown, disappeared); and
     To the extent practicable, photographs or video footage of 
the animal(s).

Actions To Minimize Additional Harm to Live-Stranded (or Milling) 
Marine Mammals

    In the event of a live stranding (or near-shore atypical milling) 
event within 50 km of the survey operations, where the NMFS stranding 
network is engaged in herding or other interventions to return animals 
to the water, the Director of OPR, NMFS (or designee), will advise L-
DEO of the need to implement shutdown procedures for all active airgun 
arrays operating within 50 km of the stranding. Shutdown procedures for 
live stranding or milling marine mammals include the following: if at 
any time, the marine mammal(s) die or are euthanized, or if herding/
intervention efforts are stopped, the Director of OPR, NMFS (or 
designee), will advise the IHA-holder that the shutdown around the 
animals' location is no longer needed. Otherwise, shutdown procedures 
will remain in effect until the Director of OPR, NMFS (or designee), 
determines and advises L-DEO that all live animals involved have left 
the area (either of their own volition or following an intervention).
    If further observations of the marine mammals indicate the 
potential for re-stranding, additional coordination with the IHA-holder 
will be required to determine what measures are necessary to minimize 
that likelihood (e.g., extending the shutdown or moving operations 
farther away) and to implement those measures as appropriate.
    Additional Information Requests--if NMFS determines that the 
circumstances of any marine mammal

[[Page 45188]]

stranding found in the vicinity of the activity suggest investigation 
of the association with survey activities is warranted, and an 
investigation into the stranding is being pursued, NMFS will submit a 
written request to L-DEO indicating that the following initial 
available information must be provided as soon as possible, but no 
later than 7 business days after the request for information:
     Status of all sound source use in the 48 hours preceding 
the estimated time of stranding and within 50 km of the discovery/
notification of the stranding by NMFS; and
     If available, description of the behavior of any marine 
mammal(s) observed preceding (i.e., within 48 hours and 50 km) and 
immediately after the discovery of the stranding.
    In the event that the investigation is still inconclusive, the 
investigation of the association of the survey activities is still 
warranted, and the investigation is still being pursued, NMFS may 
provide additional information requests, in writing, regarding the 
nature and location of survey operations prior to the time period 
above.

Negligible Impact Analysis and Determination

    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 an impact determination. In addition to 
considering estimates of the number of marine mammals that might be 
``taken'' through harassment, NMFS considers other factors, such as the 
likely nature of any impacts or responses (e.g., intensity, duration), 
the context of any impacts or responses (e.g., critical reproductive 
time or location, foraging impacts affecting energetics), as well as 
effects on habitat, and the likely effectiveness of the 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 this analysis 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, or ambient noise levels).
    To avoid repetition, the discussion of our analysis applies to all 
the species listed in Table 1, given that the anticipated effects of 
this activity on these different marine mammal stocks are expected to 
be similar. Where there are meaningful differences between species or 
stocks they are included as separate subsections below. NMFS does not 
anticipate that serious injury or mortality would occur as a result of 
L-DEO's planned survey, even in the absence of mitigation, and no 
serious injury or mortality is authorized. As discussed in the 
``Potential Effects of Specified Activities on Marine Mammals and Their 
Habitat'' section above, non-auditory physical effects and vessel 
strike are not expected to occur. NMFS expects that the majority of 
potential takes would be in the form of short-term Level B behavioral 
harassment in the form of temporary avoidance of the area or decreased 
foraging (if such activity was occurring), reactions that are 
considered to be of low severity and with no lasting biological 
consequences (e.g., Southall et al., 2007).
    We are authorizing a limited number of Level A harassment of 4 
species in the form of PTS, and Level B harassment only of the 
remaining marine mammal species. If any PTS is incurred in marine 
mammals as a result of the planned activity, we expect only a small 
degree of PTS that would not result in severe hearing impairment 
because of the constant movement of both the Langseth and of the marine 
mammals in the project areas, as well as the fact that the vessel is 
not expected to remain in any one area in which individual marine 
mammals would be expected to concentrate for an extended period of 
time. Additionally, L-DEO would shut down the airgun array if marine 
mammals approach within 500 m (with the exception of specific genera of 
dolphins, see ``Mitigation'' section), further reducing the expected 
duration and intensity of sound, and therefore the likelihood of marine 
mammals incurring PTS. Since the duration of exposure to loud sounds 
will be relatively short it would be unlikely to affect the fitness of 
any individuals. Also, as described above, we expect that marine 
mammals would likely move away from a sound source that represents an 
aversive stimulus, especially at levels that would be expected to 
result in PTS, given sufficient notice of the Langseth's approach due 
to the vessel's relatively low speed when conducting seismic surveys. 
Accordingly, we expect that the majority of takes would be in the form 
of short-term Level B behavioral harassment in the form of temporary 
avoidance of the area or decreased foraging (if such activity were 
occurring), reactions that are considered to be of low severity and 
with no lasting biological consequences (e.g., Southall et al., 2007; 
Ellison et al., 2012).
    In addition to being temporary, the maximum expected Level B 
harassment zone around the survey vessel is 6,733 m for water depths 
greater than 1,000 m (and up to 10,100 m in water depths of 100 to 
1,000 m). Therefore, the ensonified area surrounding the vessel is 
relatively small compared to the overall distribution of animals in the 
area and their use of the habitat. Feeding behavior is not likely to be 
significantly impacted as prey species are mobile and are broadly 
distributed throughout the survey area; therefore, marine mammals that 
may be temporarily displaced during survey activities are expected to 
be able to resume foraging once they have moved away from areas with 
disturbing levels of underwater noise. Because of the short duration 
(40 days) and temporary nature of the disturbance and the availability 
of similar habitat and resources in the surrounding area, the impacts 
to marine mammals and the food sources that they utilize are not 
expected to cause significant or long-term consequences for individual 
marine mammals or their populations.
    There are no rookeries, mating, or calving grounds known to be 
biologically important to marine mammals within the survey area and 
there are no feeding areas known to be biologically important to marine 
mammals within the survey area. There is no designated critical habitat 
for any ESA-listed marine mammals in the survey area.

Marine Mammal Species With Active Unusual Mortality Events (UMEs)

    There are several active UMEs occurring in the vicinity of L-DEO's 
survey area. Elevated humpback whale mortalities have occurred along 
the Atlantic coast from Maine through Florida since January 2016. Of 
the cases examined, approximately half had evidence of human 
interaction (ship strike or entanglement). The UME does not yet provide 
cause for concern regarding population-level impacts. Despite the UME, 
the relevant population of humpback whales (the West Indies breeding 
population, or

[[Page 45189]]

DPS) remains stable at approximately 12,000 individuals.
    Beginning in January 2017, elevated minke whale strandings have 
occurred along the Atlantic coast from Maine through South Carolina, 
with highest numbers in Massachusetts, Maine, and New York. This event 
does not provide cause for concern regarding population level impacts, 
as the likely population abundance is greater than 20,000 whales, and 
the UME is pending closure.
    The mitigation measures are expected to reduce the number and/or 
severity of takes for all species listed in Table 1, including those 
with active UMEs, to the level of least practicable adverse impact. In 
particular they would provide animals the opportunity to move away from 
the sound source throughout the survey area before seismic survey 
equipment reaches full energy, thus preventing them from being exposed 
to sound levels that have the potential to cause injury (Level A 
harassment) or more severe Level B harassment.
    In summary and as described above, the following factors primarily 
support our determination that the impacts resulting from this activity 
are not expected to adversely affect any of the species or stocks 
through effects on annual rates of recruitment or survival:
     No serious injury or mortality is anticipated or 
authorized;
     The activity is temporary and of relatively short duration 
(40 days);
     The vast majority of anticipated impacts of the activity 
on marine mammals would be temporary behavioral changes due to 
avoidance of the area around the vessel;
     The availability of alternative areas of similar habitat 
value for marine mammals to temporarily vacate the survey area during 
the survey to avoid exposure to sounds from the activity is readily 
abundant;
     The potential adverse effects on fish or invertebrate 
species that serve as prey species for marine mammals from the survey 
would be temporary and spatially limited, and impacts to marine mammal 
foraging would be minimal;
     The mitigation measures are expected to reduce the number 
of takes by Level A harassment (in the form of PTS) by allowing for 
detection of marine mammals in the vicinity of the vessel by visual and 
acoustic observers; and
     The mitigation measures, including visual and acoustic 
shutdowns are expected to minimize potential impacts to marine mammals 
(both amount and severity).
    Based on the analysis contained herein of the likely effects of the 
specified activity on marine mammals and their habitat, and taking into 
consideration the implementation of the monitoring and mitigation 
measures, NMFS finds that the total marine mammal take from the 
activity will have a negligible impact on all affected marine mammal 
species or stocks.

Small Numbers

    As noted previously, only take of small numbers of marine mammals 
may be authorized under sections 101(a)(5)(A) and (D) of the MMPA for 
specified activities other than military readiness activities. The MMPA 
does not define small numbers and so, in practice, where estimated 
numbers are available, NMFS compares the number of individuals taken to 
the most appropriate estimation of abundance of the relevant species or 
stock in our determination of whether an authorization is limited to 
small numbers of marine mammals. When the predicted number of 
individuals to be taken is fewer than one-third of the species or stock 
abundance, the take is considered to be of small numbers. Additionally, 
other qualitative factors may be considered in the analysis, such as 
the temporal or spatial scale of the activities.
    The amount of take NMFS is authorizing is below one-third of the 
estimated stock abundance for all species with available abundance 
estimates except for melon headed whale and Fraser's dolphin; for these 
species, the amount of take authorized by NMFS could amount to 34.5 
percent of the modeled population abundance. Applying qualitative 
factors into our analysis, however, NMFS anticipates that actual take 
will be well below the one-third threshold. First, spatial factors lead 
us to believe only small numbers of the species will be taken given 
that the survey area is a very small fraction of these species' range. 
The melon headed whale occurs in deep waters offshore of the 
southeastern U.S. and in the Gulf of Mexico extending as far south as 
southern Brazil, while Fraser's dolphin also occurs off the Western 
Atlantic in deep waters (1,000 m) from the Gulf of Mexico extending as 
far south as Uruguay. The Blake Plateau is a tiny fraction of these 
wide ranges, and NMFS does not anticipate, based on the species' 
behavior and life histories, a substantial percentage of either stock 
to concentrate in the Blake Plateau. This prediction is additionally 
informed by the fact that there have been zero OBIS database sightings 
of either species within the survey area. Second, temporal factors 
suggest only small numbers of take given that the activity would occur 
only over 40 days and during this brief period it is extremely unlikely 
that significant numbers of individual members of these species will be 
present near the survey area. Last, our calculation of 34.5 percent 
take is conservative in that it assumes that each anticipated take 
affects a different individual from the population. In fact, certain 
individuals may experience more than a single take, and given that 
fact, we would expect actual take to affect well below one-third of the 
relevant populations.
    Based on the analysis contained herein of the planned activity 
(including the mitigation and monitoring measures) and the anticipated 
take of marine mammals, NMFS finds that small numbers of marine mammals 
would be taken relative to the population size of the affected species 
or stocks.

Unmitigable Adverse Impact Analysis and Determination

    There are no relevant subsistence uses of the affected marine 
mammal stocks or species implicated by this action. Therefore, NMFS has 
determined that the total taking of affected species or stocks would 
not have an unmitigable adverse impact on the availability of such 
species or stocks for taking for subsistence purposes.

Endangered Species Act

    Section 7(a)(2) of the Endangered Species Act of 1973 (ESA; 16 
U.S.C. 1531 et seq.) requires that each Federal agency insure that any 
action it authorizes, funds, or carries out is not likely to jeopardize 
the continued existence of any endangered or threatened species or 
result in the destruction or adverse modification of designated 
critical habitat. To ensure ESA compliance for the issuance of IHAs, 
NMFS consults internally whenever we authorize take for endangered or 
threatened species, in this case with the ESA Interagency Cooperation 
Division within NMFS' OPR.
    The NMFS OPR ESA Interagency Cooperation Division issued a 
Biological Opinion under section 7 of the ESA, on the issuance of an 
IHA to L-DEO under section 101(a)(5)(D) of the MMPA by the NMFS OPR 
Permits and Conservation Division. The Biological Opinion concluded 
that the action is not likely to jeopardize the continued existence of 
ESA-listed North Atlantic right whales, blue whales, fin whales, sei 
whales, and sperm whales.

[[Page 45190]]

National Environmental Policy Act (NEPA)

    In compliance with the National Environmental Policy Act of 1969 
(42 U.S.C. 4321 et seq.), as implemented by the regulations published 
by the Council on Environmental Quality (40 CFR parts 1500-1508), the 
NSF prepared an Environmental Analysis (EA) to consider the direct, 
indirect, and cumulative effects to the human environment from the 
planned marine geophysical survey off of North Carolina. NSF's EA was 
made available to the public for review and comment in relation to its 
suitability for adoption by NMFS in order to assess the impacts to the 
human environment of issuance of an IHA to L-DEO. In compliance with 
NEPA and the Council on Environmental Quality regulations, as well as 
NOAA Administrative Order 216-6, NMFS has reviewed the NSF's EA, 
determined it to be sufficient, and adopted that EA and signed a 
Finding of No Significant Impact (FONSI) available on our website at 
https://www.fisheries.noaa.gov/action/incidental-take-authorization-lamont-doherty-earth-observatorys-marine-geophysical-surveys. NSF's EA 
is available at https://www.nsf.gov/geo/oce/envcomp/.

Authorization

    NMFS has issued an IHA to L-DEO for the incidentalharassment of 
small numbers of 29 marine mammal species incidental to a marine 
geophysical survey of Blake Plateau in the northwest Atlantic Ocean 
that includes the previously explained mitigation, monitoring and 
reporting requirements.

    Dated: July 10, 2023.
Kimberly Damon-Randall,
Director, Office of Protected Resources, National Marine Fisheries 
Service.
[FR Doc. 2023-14946 Filed 7-13-23; 8:45 am]
BILLING CODE 3510-22-P