Notice2023-10024
Takes of Marine Mammals Incidental to Specified Activities; Taking Marine Mammals Incidental to a Marine Geophysical Survey Off North Carolina in the Northwest Atlantic Ocean
Primary source
Metadata and text below are from the Federal Register, a public-domain U.S. government work. Always verify the official published version before relying on it for any legal matter.
Published
May 11, 2023
Effective
May 5, 2023
Issuing agencies
Commerce DepartmentNational Oceanic and Atmospheric Administration
Abstract
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 survey activities associated with a marine geophysical survey off North Carolina in the Northwest Atlantic Ocean.
Full Text
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<title>Federal Register, Volume 88 Issue 91 (Thursday, May 11, 2023)</title>
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[Federal Register Volume 88, Number 91 (Thursday, May 11, 2023)]
[Notices]
[Pages 30282-30299]
From the Federal Register Online via the Government Publishing Office [<a href="http://www.gpo.gov">www.gpo.gov</a>]
[FR Doc No: 2023-10024]
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DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
[RTID 0648-XC977]
Takes of Marine Mammals Incidental to Specified Activities;
Taking Marine Mammals Incidental to a Marine Geophysical Survey Off
North Carolina 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 survey activities associated with a marine geophysical
survey off North Carolina in the Northwest Atlantic Ocean.
DATES: This Authorization is effective from May 5, 2023 through May 4,
2024.
FOR FURTHER INFORMATION CONTACT: Rachel Wachtendonk, Office of
Protected Resources, NMFS, (301) 427-8401. 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:
<a href="http://www.fisheries.noaa.gov/national/marine-mammal-protection/incidental-take-authorizations-research-and-other-activities">www.fisheries.noaa.gov/national/marine-mammal-protection/incidental-take-authorizations-research-and-other-activities</a>. In case of problems
accessing these documents, please call the contact listed above.
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.
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 October 12, 2022, NMFS received a request from L-DEO for an IHA
to take marine mammals incidental to a marine geophysical survey off
the coast of North Carolina in the northwest Atlantic Ocean. The
application was deemed adequate and complete on January 13, 2023. L-DEO
requested authorization for the take of 30 species of marine mammals by
Level B harassment and, for 2 of these species, by Level A harassment.
The proposed IHA was published on March 23, 2023 (88 FR 17646). Neither
L-DEO, nor NMFS expect serious injury or mortality to result from this
activity and, therefore, an IHA is appropriate.
[[Page 30283]]
Description of Activity
Overview
Researchers from the University of Texas at Austin (UT) and L-DEO,
with funding from the NSF, and in collaboration with international and
domestic researchers including the United States Geological Survey
(USGS), propose 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 survey will occur off North
Carolina in the northwestern Atlantic Ocean during spring/summer 2023.
The multi-channel seismic (MCS) reflection survey will occur within the
Exclusive Economic Zone (EEZ) of the United States and in international
waters, in depths ranging from 200 to 5,500 meters (m). To complete
this survey, the R/V Langseth will tow an 18-airgun array consisting of
Bolt airguns ranging from 40-360 cubic inch (in\3\) each on two strings
spaced 6 m apart, with a total discharge volume of 3,300 in\3\. The
acoustic source will be towed at 6 m deep along the survey lines, while
the receiving system will consist of a 5 kilometer (km) solid-state
hydrophone streamer towed at a depth of 6 m and a 600 m long solid-
state hydrophone streamer towed at a depth of 2 to 3 m.
Dates and Duration
The survey is expected to last for 33 days, with approximately 28
days of seismic operations, 3 days of piston coring and heat flow
measurements, and 2 days of transit. R/V Langseth will likely leave
from and return to port in Norfolk, VA, during spring/summer 2023.
Specific Geographic Region
The survey will occur within ~31-35[deg] N lat., ~72-75[deg] W
long. off the coast of North Carolina in the Northwest Atlantic Ocean.
The closest point of approach of the survey area to the coast will be
approximately 40 km (from Cape Hatteras, North 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 EEZ of the U.S.
and in international waters, in depths ranging from 200-5,500 m deep.
[[Page 30284]]
[GRAPHIC] [TIFF OMITTED] TN11MY23.008
A detailed description of the planned geophysical survey is
provided in the Federal Register notice for the proposed IHA (88 FR
17646, March 23, 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 specific activity.
Comments and Responses
A notice of proposed IHA was published to the Federal Register on
March 23, 2023 (88 FR 17646). That notice described, in detail, L-DEO's
activity, the marine mammal species that may be affected by the
activity, and the anticipated effects on marine mammals. During the 30-
day public comment period, NMFS did not receive any 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. Additional reporting has been required to
notify NOAA's Southeast Regional Office (SERO) on the start and end
date of seismic operations, as well as providing daily observations if
any non-seismic activities are conducted between November and April
(note that use of airguns is prohibited during this period). Specific
language regarding the 10-knot (kn) speed restrictions in Seasonal and
Dynamic Management Areas (SMA and DMA) for North Atlantic right whale
protection was added under the vessel strike avoidance regulations.
Lastly, the contact information for the NMFS North Atlantic Right Whale
Sighting Advisory System was corrected.
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. Additional information regarding population trends and threats
may be found in NMFS' Stock Assessment Reports (SARs;
<a href="http://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessments">www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessments</a>) and more general information about these species
(e.g., physical and behavioral descriptions) may be found on NMFS'
website (<a href="http://www.fisheries.noaa.gov/find-species">www.fisheries.noaa.gov/find-species</a>). NMFS refers the reader
to the application and to the aforementioned
[[Page 30285]]
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 that stock to reach or maintain its
optimum sustainable population (as described in NMFS' SARs). While no
serious injury or mortality is expected to occur, 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: <a href="http://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessments">www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessments</a>.
Table 1--Species Likely Impacted by the Specified Activities
--------------------------------------------------------------------------------------------------------------------------------------------------------
ESA/MMPA status; Stock abundance (CV,
Common name Scientific name Stock strategic (Y/N) Nmin, most recent PBR Annual M/SI
\1\ abundance survey) \2\ \3\
--------------------------------------------------------------------------------------------------------------------------------------------------------
Order Cetartiodactyla--Cetacea--Superfamily Mysticeti (baleen whales)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Family Balaenopteridae (rorquals):
Humpback whale.................. Megaptera novaeangliae. Gulf of Maine......... -/-; N 1,396 (0; 1,380; 2016) 22 12.15
Fin whale....................... Balaenoptera physalus.. Western North Atlantic E/D; Y 6,802 (0.24; 5,573; 11 1.8
2016).
Sei whale....................... Balaenoptera borealis.. Nova Scotia........... E/D; Y 6,292 (1.02; 3,098; 6.2 0.8
2016).
Minke whale..................... Balaenoptera Canadian East Coast... -/-; N 21,968 (0.31; 17,002; 170 10.6
acutorostrata. 2016).
Blue whale...................... Balaenoptera musculus.. Western North Atlantic E/D;Y unk (unk; 402; 1980- 0.8 0
2008).
--------------------------------------------------------------------------------------------------------------------------------------------------------
Superfamily Odontoceti (toothed whales, dolphins, and porpoises)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Family Physeteridae:
Sperm whale..................... Physeter macrocephalus. North Atlantic........ E/D;Y 4,349 (0.28; 3,451; 3.9 0
2016).
Family Kogiidae:
Pygmy sperm whale............... Kogia breviceps........ Western North Atlantic -/-; N 7,750 (0.38; 5,689; 46 0
2016).
Dwarf sperm whale............... Kogia sima............. Western North Atlantic -/-; N 7,750 (0.38; 5,689; 46 0
2016).
Family Ziphiidae (beaked whales):
Cuvier's beaked Whale........... Ziphius cavirostris.... Western North Atlantic -/-; N 5,744 (0.36; 4,282; 43 0.2
2016).
Blainville's beaked Whale....... Mesoplodon densirostris Western North Atlantic -/-; N 10,107 (0.27; 8,085; 81 0
2016).
True's beaked whale............. Mesoplodon mirus....... Western North Atlantic -/-; N 10,107 (0.27; 8,085; 81 0
2016).
Gervais' beaked whale........... Mesoplodon europaeus... Western North Atlantic -/-; N 10,107 (0.27; 8,085; 81 0
2016).
Family Delphinidae:
Long-finned pilot whale......... Globicephala melas..... Western North Atlantic -/-; N 39,215 (0.30; 30,627; 306 9
2016).
Short finned pilot whale........ Globicephala Western North Atlantic -/-;Y 28,924 (0.24; 23,637; 236 136
macrorhynchus. 2016).
Rough-toothed dolphin........... Steno bredanensis...... Western North Atlantic -/-; N 136 (1.0; 67; 2016)... 0.7 0
Bottlenose dolphin.............. Tursiops truncates..... Western North Atlantic -/-; N 62,851 (0.23; 51,914; 519 28
Offshore. 2016).
Atlantic white-sided dolphin.... Lagenorhynchus acutus.. Western North Atlantic -/-; N 93,233 (0.71; 54,443; 544 27
2016).
Pantropical spotted dolphin..... Stenella attenuate..... Western North Atlantic -/-; N 6,593 (0.52; 4,367; 44 0
2016).
Atlantic spotted dolphin........ Stenella frontalis..... Western North Atlantic -/-; N 39,921 (0.27; 32,032; 320 0
2016).
Spinner dolphin................. Stenella longirostris.. Western North Atlantic -/-; N 4,102 (0.99; 2,045; 21 0
2016).
Clymene dolphin................. Stenella clymene....... Western North Atlantic -/-; N 4,237 (1.03; 2,071; 21 0
2016).
Striped dolphin................. Stenella coeruleoalba.. Western North Atlantic -/-; N 67,036 (0.29; 52,939; 529 0
2016).
Fraser's dolphin................ Lagenodelphis hosei.... Western North Atlantic -/-; N unk................... unk 0
Risso's dolphin................. Grampus griseus........ Western North Atlantic -/-; N 35,215(0.19; 30,051; 301 34
2016).
Common dolphin.................. Delphinus delphis...... Western North Atlantic -/-; N 172,947 (0.21; 1,452 390
145,216; 2016).
Melon-headed whale.............. Peponocephala electra.. Western North Atlantic -/-; N unk................... unk 0
Pygmy killer whale.............. Feresa attenuate....... Western North Atlantic -/-; N unk................... unk 0
False killer whale.............. Pseudorca crassidens... Western North Atlantic -/-; N 1,791 (0.56; 1,154; 12 0
2016).
Killer whale.................... Orcinus orca........... Western North Atlantic -/-; N unk................... unk 0
Family Phocoenidae (porpoises):
Harbor porpoise................. Phocoena phocoena...... Gulf of Maine/Bay of -/-; N 95,543 (0.31; 74,034; 851 164
Fundy. 2016).
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ Endangered Species Act (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: <a href="https://www.nmfs.noaa.gov/pr/sars/">https://www.nmfs.noaa.gov/pr/sars/</a>. CV is coefficient of variation; Nmin is the minimum
estimate of stock abundance.
\3\ These values, found in NMFS's SARs, represent annual levels of human-caused mortality plus serious injury from all sources combined (e.g.,
commercial fisheries, ship strike). Annual M/SI often cannot be determined precisely and is in some cases presented as a minimum value or range. A CV
associated with estimated mortality due to commercial fisheries is presented in some cases.
[[Page 30286]]
As indicated above, all 30 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 off North Carolina), 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 17646, March 23, 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 (<a href="https://www.fisheries.noaa.gov/find-species">https://www.fisheries.noaa.gov/find-species</a>) 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 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 low-frequency 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 150 Hz to 160 kHz.
(dolphins, 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) 50 Hz to 86 kHz.
(true seals).
Otariid pinnipeds (OW) (underwater) 60 Hz to 39 kHz.
(sea 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 17646, March 23,
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 proposed IHA (88 FR
17646, March 23, 2023).
Estimated Take
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).
Authorized takes will primarily be Level B harassment, as use of
the described acoustic sources, particularly airgun arrays, is likely
to disrupt behavioral patterns of marine mammals. There is also some
potential for auditory injury (Level A harassment) to result for low-
and high-frequency species due to the size of the predicted auditory
injury zones for those species. Auditory injury is less likely to occur
for mid-frequency 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 high-frequency cetaceans. As discussed in further
detail below, we do not expect auditory injury for low- or mid-
frequency 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
[[Page 30287]]
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 survey includes the use of impulsive seismic sources (e.g.,
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
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:
<a href="http://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-acoustic-technical-guidance">www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-acoustic-technical-guidance</a>.
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: Cell 2: LE,LF,24h:
219 dB; 199 dB.
LE,LF,24h: 183 dB.
Mid-Frequency (MF) Cetaceans.... Cell 3: Lpk,flat: Cell 4: LE,MF,24h:
230 dB; 198 dB.
LE,MF,24h: 185 dB.
High-Frequency (HF) Cetaceans... Cell 5: Lpk,flat: Cell 6: LE,HF,24h:
202 dB; 173 dB.
LE,HF,24h: 155 dB.
Phocid Pinnipeds (PW) Cell 7: Lpk,flat: Cell 8: LE,PW,24h:
(Underwater). 218 dB; 201 dB.
LE,PW,24h: 185 dB.
Otariid Pinnipeds (OW) Cell 9: Lpk,flat: Cell 10:
(Underwater). 232 dB; LE,OW,24h: 219
LE,OW,24h: 203 dB. 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 [mu]Pa, and
cumulative sound exposure level (LE) has a reference value of
1[mu]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 (2016) 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
[[Page 30288]]
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 survey will entail the use of a 18-airgun array with a total
discharge of 3300 in\3\ at a tow depth of 6 m. L-DEO model results are
used to determine the 160 dB<INF>rms</INF> radius for the 18-airgun
array in water depth ranging from 200-5500 m. Received sound levels
were predicted by L-DEO's model (Diebold et al., 2010) as a function of
distance from L-DEO's full 36 airgun array (versus the smaller array
planned for use here). Models for the 36-airgun array used a 12-m tow
depth, versus the 6-m tow depth planned for this survey. 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 (~600-1100 m), and shallow water
(~50 m) in the Gulf of Mexico in 2007-2008 (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 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 Appendix H of the NSF-USGS PEIS). 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 Appendix H of the NSF-USGS PEIS). 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 will acquire data with the 18-airgun array at a tow
depth of 6 m. For deep water (>1,000 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 18-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 Appendix H of PEIS).
L-DEO's modeling methodology is described in greater detail in the
IHA application. The estimated distances to the Level B harassment
isopleth for the airgun configuration are shown in Table 4.
Table 4--Predicted Radial Distances From the R/V Langseth Seismic Source to Isopleth Corresponding to Level B
Harassment Threshold
----------------------------------------------------------------------------------------------------------------
Predicted
distances (in
m) to the
Airgun configuration Tow depth (m) Water depth (m) level B
harassment
threshold
----------------------------------------------------------------------------------------------------------------
18 airguns, 3300 in \3\.................... 6 >1000 m............................ \a\ 2,886
100-1000 m......................... \b\ 4,329
----------------------------------------------------------------------------------------------------------------
\a\ Distance is based on L-DEO model results.
\b\ 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 marine mammal
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
----------------------------------------------------------------------------------------------------------------
LF MF HF
----------------------------------------------------------------------------------------------------------------
PTS SELcum...................................................... 101.9 0 0.5
PTS Peak........................................................ 23.3 11.2 116.9
----------------------------------------------------------------------------------------------------------------
Note: The largest distance (in bold) of the dual criteria (Sound Exposure Level (SEL) cum 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 Technical Guidance
were presented as dual metric acoustic thresholds using both
SEL<INF>cum</INF> and peak sound pressure
[[Page 30289]]
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 SEL<INF>cum</INF> 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 SEL<INF>cum</INF> 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 SEL<INF>cum</INF> for the 18-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 farfield signature. Because the farfield
signature does not take into account the large array effect near the
source and is calculated as a point source, the farfield signature is
not an appropriate measure of the sound source level for large arrays.
See the application for further detail on acoustic modeling.
Auditory injury is unlikely to occur for mid-frequency cetaceans
given very small modeled zones of injury for those species, 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 2-3 times the array dimensions, pressure peaks from
individual elements do not arrive simultaneously because the
observation point is not 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 will 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 farfield (Table 5). For a specific array,
one can estimate the distance at which the near-field transitions to
the farfield by:
[GRAPHIC] [TIFF OMITTED] TN11MY23.009
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] TN11MY23.010
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] TN11MY23.011
and calculate D directly given a particular frequency and known speed
of sound (here assumed to be 1,500 meters 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/farfield 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 3,300-in\3\ airgun array planned for
use during the survey has an approximate diagonal of 18.6 m, resulting
in a near-field distance of approximately 58 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 58-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 (58 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
[[Page 30290]]
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
will be below those assumed here, we believe exceedance of the peak
pressure threshold will 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 mid-
frequency cetaceans to be minimal, 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 low- or mid-frequency cetacean
and do not propose to authorize any 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]Parms 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 that
will inform the take calculations.
Habitat-based density models produced by the Duke University Marine
Geospatial Ecology Laboratory (Roberts et al., 2016; Roberts and
Halpin, 2022) represent the best available information regarding marine
mammal densities in the survey area. The density data presented by
Roberts et al. (2016 and 2022) 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 <a href="https://seamap.env.duke.edu/models/Duke/EC">https://seamap.env.duke.edu/models/Duke/EC</a>/.
Marine mammal density estimates in the survey area (animals/km\2\) were
obtained using the most recent model results for all taxa (Roberts et
al., 2016 and 2022).
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 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 is 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 by
25 percent, and then multiplied by the number of survey days (28) 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 authorized take 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., mid-frequency 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 planned
for authorization. Estimated exposures and take numbers for
authorization are shown in Table 6.
Table 6--Estimated Take for Authorization
--------------------------------------------------------------------------------------------------------------------------------------------------------
Estimated take Authorized take
Species Stock ---------------------------------------------------------------- Stock abundance Percent of stock
Level B Level A Level B Level A
--------------------------------------------------------------------------------------------------------------------------------------------------------
North Atlantic right whale..... Western North 0.03 0 0 0 368.............. n/a
Atlantic.
Humpback whale................. Gulf of Maine.... 0.06 0 \1\ 2 0 1,396............ 0.14
Fin whale...................... Western North 4 0 4 0 6,802............ 0.06
Atlantic.
Sei whale...................... Nova Scotia...... 8 0 8 0 6,292............ 0.13
Minke whale.................... Canadian East 10 0 10 0 21,968........... 0.05
Coast.
Blue whale..................... Western North 1 0 1 0 402.............. 0.17
Atlantic.
Sperm whale.................... North Atlantic... 405 1 406 0 4,349............ 9.34
Kogia spp...................... ................. 678 31 678 31 15,500........... 0.04
[[Page 30291]]
Cuvier's beaked whale.......... Western North 394 2 396 0 5,744............ 6.89
Atlantic.
Mesoplodont Beaked whales...... ................. 418 2 420 0 30,321........... 1.38
Pilot whales................... ................. 384 1 385 0 15,500........... 2.48
Rough-toothed dolphin.......... Western North 82 0 82 0 136.............. 10.79
Atlantic.
Bottlenose dolphin............. Western North 1,473 4 1,477 0 62,851........... 2.35
Atlantic
Offshore.
Atlantic white-sided dolphin... Western North 0 0 \1\ 14 0 93,233........... 0.02
Atlantic.
Pantropical spotted dolphin.... Western North 114 0 114 0 6,593............ 1.73
Atlantic.
Atlantic spotted dolphin....... Western North 1,232 5 1,237 0 39,921........... 3.1
Atlantic.
Spinner dolphin................ Western North 41 0 41 0 4,102............ 1.00
Atlantic.
Clymene dolphin................ Western North 79 0 79 0 4,237............ 1.87
Atlantic.
Striped dolphin................ Western North 19 0 \1\ 45 0 67,036........... 0.07
Atlantic.
Fraser's dolphin............... Western North 62 0 \2\ 163 0 unk.............. .................
Atlantic.
Risso's dolphin................ Western North 189 0 189 0 35,215........... 0.54
Atlantic.
Common dolphin................. Western North 56 0 56 0 172,947.......... 11.99
Atlantic.
Melon-headed whale............. Western North 58 0 \2\ 83 0 3,965............ 2.15
Atlantic.
Pygmy killer whale............. Western North 6 0 6 0 unk.............. .................
Atlantic.
False killer whale............. Western North 1 0 \2\ 6 0 1,791............ 0.34
Atlantic.
Killer whale................... Western North 2 0 \1\ 4 0 unk.............. .................
Atlantic.
Harbor porpoise................ Gulf of Maine/Bay 0.01 0 \1\ 3 0 95,543........... 0.00
of Fundy.
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ Take increased to mean group size from the Atlantic Marine Assessment Program for Protected Species (AMAPPS; Palka et al., 2017 and 2021).
\2\ Take increased to mean group size from the Ocean Biodiversity Information System (OBIS 2023).
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 stocks, and their habitat, as
well as subsistence uses. 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
[[Page 30292]]
also acts as an extension of the SZ in that observations of marine
mammals within the buffer zone will 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, 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
acoustic source is planned to occur, and whenever the acoustic source
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 acoustic source
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 acoustic source (rather than being based on the center of the array
or around the vessel itself). During use of the acoustic source (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 acoustic source. 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
acoustic source is not operating for comparison of sighting rates and
behavior with and without use of the acoustic source 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 (PAM)
Acoustic monitoring 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 will 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 will 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 will 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 of the acoustic
source. 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 PAM operator diagnoses the issue.
If the diagnosis indicates that the PAM system must be repaired to
solve the problem, operations may continue for an additional 5 hours
without acoustic monitoring during daylight hours only under the
following conditions:
<bullet> Sea state is less than or equal to BSS 4;
<bullet> No marine mammals (excluding delphinids) detected solely
by PAM in the applicable EZ in the previous 2 hours;
<bullet> 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
<bullet> Operations with an active acoustic source, but without an
operating PAM system, do not exceed a cumulative total of 5 hours in
any 24-hour period.
[[Page 30293]]
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 will establish a minimum SZ with a 500-m radius. The 500-m SZ will
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 acoustic source will 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 acoustic
source, and includes the SZ plus the buffer zone. Detections of marine
mammals within the pre-start clearance zone will prevent airgun
operations from beginning (i.e., ramp-up).
The 500-m SZ is intended to be precautionary in the sense that it
will be expected to contain sound exceeding the injury criteria for all
cetacean hearing groups, (based on the dual criteria of
SEL<INF>cum</INF> and peak SPL), while also providing a consistent,
reasonably observable zone within which PSOs will 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.
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 protected
species are observed within the pre-clearance zone (or extended SZ, for
beaked whales and Kogia spp.) prior to the beginning of ramp-up. During
pre-start clearance period is the only time observations of marine
mammals in the buffer zone will 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 acoustic
source. All operators must adhere to the following pre-start clearance
and ramp-up requirements:
<bullet> 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);
<bullet> Ramp-ups shall be scheduled so as to minimize the time
spent with the source activated prior to reaching the designated run-
in;
<bullet> 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;
<bullet> 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);
<bullet> 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;
<bullet> 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;
<bullet> 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. Acoustic
source activation may only occur at times of poor visibility where
operational planning cannot reasonably avoid such circumstances;
<bullet> If the acoustic source is shut down for brief periods
(i.e., less than 30 minutes) for reasons other than that described for
shutdown (e.g., mechanical difficulty), it may be activated again
without ramp-up if PSOs have maintained constant visual and/or acoustic
observation and no visual or acoustic detections of marine mammals have
occurred within the applicable SZ. For any longer shutdown, pre-start
clearance observation and ramp-up are required. For any shutdown at
night or in periods of poor visibility (e.g., BSS 4 or greater), ramp-
up is required, but if the shutdown period was brief and constant
observation was maintained, pre-start clearance watch of 30 minutes is
not required; and
<bullet> Testing of the acoustic source 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 min.
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 acoustic source 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 acoustic source 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
[[Page 30294]]
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 acoustic source will be shut down. When shutdown is called for by a
PSO, the acoustic source 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 will not resume until the
marine mammal has cleared the SZ. The animal will 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 will
typically be the only marine mammals likely to intentionally approach
the vessel. As described above, auditory injury is extremely unlikely
to occur for mid-frequency 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
in those delphinoids (e.g., Barkaszi et al., 2012, Barkaszi and Kelly,
2018). The potential for increased shutdowns resulting from such a
measure will 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 mid-frequency 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 will 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 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 operators and crews must maintain a vigilant watch for all
protected species and slow down, stop their vessel, or alter course, as
appropriate and regardless of vessel size, to avoid striking any marine
mammal. 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) distinguish marine mammals from other phenomena, and (2) broadly
identify a marine mammal as a whale or other marine mammal.
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 North Atlantic right whales and 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.
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.
All survey vessels, regardless of size, must observe a 10-kn 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) established under 50 CFR 224.105 (when
in effect), any dynamic management areas (DMA) (when in effect), and
Slow Zones. See www.fisheries.noaa.gov/national/endangered-species-
conservation/reducing-ship-strikes-north-atlantic-
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right-whales for specific detail regarding these areas.
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, daily PSO logs must be sent
to the NOAA 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 (<a href="/cdn-cgi/l/email-protection#2e4043485d005d4b5c005c4b5d4b4f5c4d460040415a4748474d4f5a4741406e40414f4f00494158"><span class="__cf_email__" data-cfemail="f896959e8bd68b9d8ad68a9d8b9d998a9b90d696978c919e919b998c919796b896979999d69f978e">[email protected]</span></a>).
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:
<bullet> Occurrence of marine mammal species or stocks in the area
in which take is anticipated (e.g., presence, abundance, distribution,
density);
<bullet> 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);
<bullet> Individual marine mammal responses (behavioral or
physiological) to acoustic stressors (acute, chronic, or cumulative),
other stressors, or cumulative impacts from multiple stressors;
<bullet> How anticipated responses to stressors impact either: (1)
long-term fitness and survival of individual marine mammals; or (2)
populations, species, or stocks;
<bullet> Effects on marine mammal habitat (e.g., marine mammal prey
species, acoustic habitat, or other important physical components of
marine mammal habitat); and,
<bullet> Mitigation and monitoring effectiveness.
Vessel-Based Visual Monitoring
As described above, PSO observations will take place during daytime
airgun operations. During seismic survey operations, at least five
visual PSOs will be based aboard the Langseth. Two visual PSOs will be
on duty at all times during daytime hours. Monitoring shall be
conducted in accordance with the following requirements:
<bullet> 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 (i.e., Fujinon or equivalent) 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
<bullet> 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:
<bullet> PSOs shall be independent, dedicated, trained visual and
acoustic PSOs and must be employed by a third-party observer provider;
<bullet> 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);
<bullet> 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;
<bullet> 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;
<bullet> 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;
<bullet> 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;
<bullet> 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
<bullet> 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 data
collection forms, whether hard copy or electronic. PSOs shall record
detailed information about any implementation of mitigation
requirements, including the distance of animals to the acoustic source
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 acoustic source. If
required mitigation was not
[[Page 30296]]
implemented, PSOs should record a description of the circumstances. At
a minimum, the following information must be recorded:
<bullet> Vessel names (source vessel and other vessels associated
with survey) and call signs;
<bullet> PSO names and affiliations;
<bullet> Dates of departures and returns to port with port name;
<bullet> Date and participants of PSO briefings;
<bullet> Dates and times (Greenwich Mean Time) of survey effort and
times corresponding with PSO effort;
<bullet> Vessel location (latitude/longitude) when survey effort
began and ended and vessel location at beginning and end of visual PSO
duty shifts;
<bullet> Vessel heading and speed at beginning and end of visual
PSO duty shifts and upon any line change;
<bullet> 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;
<bullet> Factors that may have contributed to impaired observations
during each PSO shift change or as needed as environmental conditions
changed (e.g., vessel traffic, equipment malfunctions); and
<bullet> Survey activity information, such as acoustic source 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.).
The following information should be recorded upon visual
observation of any protected species:
<bullet> Watch status (sighting made by PSO on/off effort,
opportunistic, crew, alternate vessel/platform);
<bullet> PSO who sighted the animal;
<bullet> Time of sighting;
<bullet> Vessel location at time of sighting;
<bullet> Water depth;
<bullet> Direction of vessel's travel (compass direction);
<bullet> Direction of animal's travel relative to the vessel;
<bullet> Pace of the animal;
<bullet> Estimated distance to the animal and its heading relative
to vessel at initial sighting;
<bullet> 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;
<bullet> Estimated number of animals (high/low/best);
<bullet> Estimated number of animals by cohort (adults, yearlings,
juveniles, calves, group composition, etc.);
<bullet> 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);
<bullet> 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);
<bullet> Animal's closest point of approach (CPA) and/or closest
distance from any element of the acoustic source;
<bullet> Platform activity at time of sighting (e.g., deploying,
recovering, testing, shooting, data acquisition, other); and
<bullet> Description of any actions implemented in response to the
sighting (e.g., delays, shutdown, ramp-up) and time and location of the
action.
If a marine mammal is detected while using the PAM system, the
following information should be recorded:
<bullet> An acoustic encounter identification number, and whether
the detection was linked with a visual sighting;
<bullet> Date and time when first and last heard;
<bullet> Types and nature of sounds heard (e.g., clicks, whistles,
creaks, burst pulses, continuous, sporadic, strength of signal); and
<bullet> 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
L-DEO must submit a draft comprehensive report to NMFS on all
activities and monitoring results within 90 days of the completion of
the survey or expiration of the IHA, whichever comes sooner. A final
report must be submitted within 30 days following resolution of any
comments on the draft report. The report will describe the operations
that were conducted and sightings of marine mammals near the
operations. The report will provide full documentation of methods,
results, and interpretation pertaining to all monitoring. The 90-day
report will summarize the dates and locations of seismic operations,
and all marine mammal sightings (dates, times, locations, activities,
associated seismic survey activities). The report will also include
estimates of the number and nature of exposures that occurred above the
harassment threshold based on PSO observations and including an
estimate of those that were not detected, in consideration of both the
characteristics and behaviors of the species of marine mammals that
affect detectability, as well as the environmental factors that affect
detectability.
The draft report shall also include geo-referenced time-stamped
vessel tracklines for all time periods during which airguns were
operating. Tracklines should include points recording any change in
airgun status (e.g., when the airguns began operating, when they were
turned off, or when they changed from full array to single gun or vice
versa). Geographic Information Systems (GIS) files shall be provided in
Environmental Systems Research Institute (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 to NMFS. A final report
must be submitted within 30 days following resolution of any comments
on the draft report.
Reporting Species of Concern
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 survey activities covered by the authorization
discover an injured or dead marine mammal, the L-DEO shall report the
incident to the Office of Protected Resources (OPR), NMFS and to the
NMFS South East Regional Stranding Coordinator as soon as feasible. The
report must include the following information:
<bullet> Time, date, and location (latitude/longitude) of the first
discovery (and updated location information if known and applicable);
<bullet> Species identification (if known) or description of the
animal(s) involved;
<bullet> Condition of the animal(s) (including carcass condition if
the animal is dead);
[[Page 30297]]
<bullet> Observed behaviors of the animal(s), if alive;
<bullet> If available, photographs or video footage of the
animal(s); and
<bullet> General circumstances under which the animal was
discovered.
Vessel strike--In the event of a ship 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 South East
Regional Stranding Coordinator as soon as feasible. The report must
include the following information:
<bullet> Time, date, and location (latitude/longitude) of the
incident;
<bullet> Vessel's speed during and leading up to the incident;
<bullet> Vessel's course/heading and what operations were being
conducted (if applicable);
<bullet> Status of all sound sources in use;
<bullet> 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;
<bullet> Environmental conditions (e.g., wind speed and direction,
Beaufort sea state, cloud cover, visibility) immediately preceding the
strike;
<bullet> Species identification (if known) or description of the
animal(s) involved;
<bullet> Estimated size and length of the animal that was struck;
<bullet> Description of the behavior of the animal immediately
preceding and following the strike;
<bullet> If available, description of the presence and behavior of
any other marine mammals present immediately preceding the strike;
<bullet> 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
<bullet> 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 acoustic
sources 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 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 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:
<bullet> 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
<bullet> 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 will 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 potential
takes will 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). Even repeated Level B harassment of some small
subset of an overall stock is unlikely to result in any significant
realized decrease in viability for the affected individuals, and thus
will not result in any adverse impact to the stock as a whole.
We authorized a limited number of instances of Level A harassment
of two species (pygmy and dwarf sperm
[[Page 30298]]
whales, which are members of the high-frequency cetacean hearing group)
in the form of PTS, and Level B harassment only of the remaining marine
mammal species. Any PTS incurred in marine mammals as a result of the
activity is expected to be in the form of a small degree of PTS, and
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 will be expected to
concentrate for an extended period of time. Additionally, L-DEO will
shut down the airgun array if marine mammals approach within 500 m
(with the exception of specific genera of dolphins, see Mitigation),
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 will 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 will 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 2,886 m for water depths
greater than 1,000 m (and up to 4,329 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
(28 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
As discussed above, 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 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.
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 will 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. No Level A harassment is
anticipated, even in the absence of mitigation measures, or authorized
for species with active UMEs.
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:
<bullet> No serious injury or mortality is anticipated or
authorized;
<bullet> The activity is temporary and of relatively short duration
(28 days);
<bullet> The anticipated impacts of the activity on marine mammals
will be temporary behavioral changes due to avoidance of the area
around the vessel;
<bullet> 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;
<bullet> The potential adverse effects on fish or invertebrate
species that serve as prey species for marine mammals from the survey
will be temporary and spatially limited, and impacts to marine mammal
foraging will be minimal;
<bullet> 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
<bullet> 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 small numbers of incidental take 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
[[Page 30299]]
as the temporal or spatial scale of the activities.
The amount of take NMFS authorized is below one third of the
estimated stock abundance for all species with available abundance
estimates (in fact, take of individuals is less than fifteen percent of
the abundance of the affected stocks, see Table 6). This is likely a
conservative estimate because we assume all takes are of different
individual animals, which is likely not the case. Some individuals may
be encountered multiple times in a day, but PSOs will count them as
separate individuals if they cannot be identified.
NMFS considers it appropriate to make a small numbers finding in
the case of a species or stock that may potentially be taken but is
either rarely encountered or only expected to be taken on rare
occasions. In that circumstance, one or two assumed encounters with a
group of animals (meaning a group that is traveling together or
aggregated, and thus exposed to a stressor at the same approximate
time) should reasonably be considered small numbers, regardless of
consideration of the proportion of the stock (if known), as rare
encounters resulting in take of one or two groups should be considered
small relative to the range and distribution of any stock. In this
case, NMFS authorized take resulting from a single exposure of one
group each for Fraser's dolphin and killer whale (using average group
size), and find that a single incident of take of one group of either
of these species represents take of small numbers for that species.
For pygmy killer whale, we authorized six incidents of take by
Level B harassment. No abundance information is available for this
species in the survey area. Therefore, we refer to other SAR abundance
estimates for the species. NMFS estimates that the Hawaii stock of
pygmy killer whales has a minimum abundance estimate of 5,885 whales
(Carretta et al., 2020). In the Gulf of Mexico, NMFS estimates a
minimum abundance of 613 whales for that stock (Hayes et al., 2020).
Therefore, NMFS assumes that the estimated take number of six would be
small relative to any reasonable estimate of population abundance for
the species in the Atlantic.
Based on the analysis contained herein of the 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 will 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 propose to authorize take for
endangered or threatened species, in this case with the ESA Interagency
Cooperation Division within NMFS' Office of Protected Resources (OPR).
The NMFS Office of Protected Resources 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.
National Environmental Policy Act
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
National Science Foundation 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 CEQ 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). NSF's EA is available at <a href="https://www.nsf.gov/geo/oce/envcomp/north-carolina-2023/LDEO-NC-EA-7-Oct2022.pdf">https://www.nsf.gov/geo/oce/envcomp/north-carolina-2023/LDEO-NC-EA-7-Oct2022.pdf</a>.
Authorization
NMFS has issued an IHA to L-DEO for the potential harassment of
small numbers of 30 marine mammal species incidental to a marine
geophysical survey off North Carolina in the Northwest Atlantic Ocean
that includes the previously explained mitigation, monitoring and
reporting requirements.
Dated: May 5, 2023.
Kimberly Damon-Randall,
Director, Office of Protected Resources, National Marine Fisheries
Service.
[FR Doc. 2023-10024 Filed 5-10-23; 8:45 am]
BILLING CODE 3510-22-P
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