Notice2022-09792
Takes of Marine Mammals Incidental to Specified Activities; Taking Marine Mammals Incidental to Geophysical Surveys of the Guerrero Gap in the Eastern Tropical Pacific
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 6, 2022
Effective
May 2, 2022
Issuing agencies
Commerce DepartmentNational Oceanic and Atmospheric Administration
Abstract
In accordance with the regulations implementing the Marine Mammal Protection Act (MMPA) as amended, NMFS has issued an IHA to the Lamont-Doherty Earth Observatory (L-DEO) to incidentally harass marine mammals during geophysical surveys of the Guerrero Gap off the coast of Mexico in the Eastern Tropical Pacific.
Full Text
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<title>Federal Register, Volume 87 Issue 88 (Friday, May 6, 2022)</title>
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[Federal Register Volume 87, Number 88 (Friday, May 6, 2022)]
[Notices]
[Pages 27111-27131]
From the Federal Register Online via the Government Publishing Office [<a href="http://www.gpo.gov">www.gpo.gov</a>]
[FR Doc No: 2022-09792]
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DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
[RTID 0648-XB866]
Takes of Marine Mammals Incidental to Specified Activities;
Taking Marine Mammals Incidental to Geophysical Surveys of the Guerrero
Gap in the Eastern Tropical Pacific
AGENCY: National Marine Fisheries Service (NMFS), National Oceanic and
Atmospheric Administration (NOAA), Commerce.
ACTION: Notice; issuance of an incidental harassment authorization
(IHA).
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SUMMARY: In accordance with the regulations implementing the Marine
Mammal Protection Act (MMPA) as amended, NMFS has issued an IHA to the
Lamont-Doherty Earth Observatory (L-DEO) to incidentally harass marine
mammals during geophysical surveys of the Guerrero Gap off the coast of
Mexico in the Eastern Tropical Pacific.
DATES: This authorization is effective from May 2, 2022 through May 1,
2023.
FOR FURTHER INFORMATION CONTACT: Amy Fowler, 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="https://www.fisheries.noaa.gov/permit/incidental-take-authorizations-under-marine-mammal-protection-act">https://www.fisheries.noaa.gov/permit/incidental-take-authorizations-under-marine-mammal-protection-act</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 incidental harassment authorization 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 August 21, 2021, NMFS received a request from L-DEO for an IHA
to take marine mammals incidental to geophysical surveys of the
Guerrero Gap off the coast of Mexico in the Eastern Tropical Pacific
(ETP). The application was deemed adequate and complete on December 14,
2021. L-DEO's request is for take of a small number of 30 species of
marine mammals by Level B harassment and, for two of those species, by
Level A harassment. NMFS published a notice of proposed IHA for public
review and comment on January 12, 2022 (87 FR 1992). Neither L-DEO nor
NMFS expects serious injury or mortality to result from this activity
and, therefore, an IHA is appropriate.
Description of Planned Activity
Researchers from L-DEO, University of Texas Institute of Geophysics
(UTIG), and Northern Arizona University (NAU), with funding from the
National Science Foundation (NSF), and in collaboration with
researchers from the National Autonomous University of Mexico
(Universidad Nacional Autonoma de Mexico or UNAM) and Kyoto University,
plan to conduct high-energy seismic surveys from the research vessel
(R/V) Marcus G. Langseth (Langseth) in and around the Guerrero Gap off
western Mexico, in the ETP in the mid- to late-spring of 2022. The
study uses two-dimensional (2-D) seismic surveying to quantify incoming
plate hydration and examine the role of fluids on megathrust slip
behavior in and around the Guerrero Gap of the Middle America Trench.
L-DEO plans to conduct two different methods of seismic acquisition,
multi-channel seismic (MCS) using a hydrophone streamer and refraction
surveys using ocean bottom seismometers (OBSs). A total of 3,600
kilometers (km) of transect lines would be surveyed (2,230 km of 2-D
MCS reflection data and 1,370 km of OBS refraction data). Approximately
62 percent of the total survey effort would be MCS surveys, with the
remaining 38 percent using OBSs. The planned surveys use a 36-airgun
towed array with a total discharge volume of ~6600 cubic inches (in\3\)
as an acoustic source, acquiring return signals using both a towed
streamer as well as OBSs. The total survey duration will be
approximately 48 days, including approximately 20 days of seismic
survey operations, 3 days of transit to and from the survey area, 19
days for equipment deployment/recovery, and 6 days of contingency time
for poor weather, etc.
The majority of the 2-D seismic surveys would occur within the
Exclusive Economic Zone (EEZ) of Mexico, including territorial seas,
and a small portion would occur in International Waters. Approximately
6 percent of the total survey effort would occur in Mexican territorial
waters. Note that the MMPA does not apply in Mexican territorial
waters. L-DEO is subject only to Mexican law in conducting that portion
of the survey. However, NMFS has calculated the expected level of
incidental take in the entire activity area (including Mexican
territorial waters) as part of the analysis supporting our
determination under the MMPA that the activity will have a negligible
impact on the affected species or stocks (see Estimated Take and
[[Page 27112]]
Negligible Impact Analysis and Determination).
A detailed description of the planned geophysical surveys is
provided in the Federal Register notice for the proposed IHA (87 FR
1992; January 12, 2022). 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 NMFS's proposal to issue an IHA to L-DEO was published
in the Federal Register on January 12, 2022 (87 FR 1992). 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 received comment
letters from the Center for Biological Diversity (CBD), Whales of
Guerrero, and the Sociedad Mexicana de Mastozoolog[iacute]a Marina,
A.C. (SOMEMMA). The Sociedad Mexicana de Mastozoolog[iacute]a Marina's
comment letter was written in support of and reiterated the
recommendations in the Whales of Guerrero letter, and we therefore
address their comments together.
Comment 1: Whales of Guerrero and SOMEMMA highlighted the status of
the endangered Central America Distinct Population Segment (DPS) of
humpback whales. Whales of Guerrero noted that in addition to
transiting through the survey area along their migratory route,
humpback whales from the Central America DPS have been observed
calving, nursing, resting, and breeding in the planned survey area
between November and May. Citing their own research surveys, Whales of
Guerrero recommended that seismic surveys not occur in the region
between November 1 and May 1 to ensure minimal impact on the Central
America DPS humpback whales.
Response: As required under the MMPA, NMFS preliminarily determined
that the mitigation measures in the proposed IHA set forth the means of
effecting the least practicable impact on the species and its habitat.
``Minimal impact''--which was not defined by the commenter--is not the
standard that must be met through the prescription of mitigation
requirements. However, in consideration of the data and maps provided
by Whales of Guerrero in their comment letter, showing humpback whale
presence concentrated in nearshore waters, and on review of its survey
plans, L-DEO agreed that limiting surveys of nearshore tracklines to
between May 1 and October 31 would be practicable. NMFS here defines
``nearshore'' tracklines as those tracklines planned to occur in areas
where humpback whale sightings (as provided by Whales of Guerrero in
their comment letter) have been recorded during the migratory period
(i.e., until May 1), or where the associated estimated Level B
harassment area would overlap areas where humpback whale sightings have
been recorded. This definition includes tracklines within approximately
33.4 km of shore (i.e., the maximum reported distance from shore of
humpback sightings in the area). For example, this definition includes
the 264-km MCS and OBS trackline running parallel to shore off
Guerrero, as well as all connector lines and portions of tracklines
landward of that trackline (see Figure 1 of L-DEO's IHA application).
NMFS has included this requirement in the final IHA.
Comment 2: Whales of Guerrero and SOMEMMA noted that at least 16
additional species of marine mammals occur in the survey area,
including endangered species and species with limited data on abundance
and status. Whales of Guerrero included a table of sightings of these
species over the course of their research activities between 2014 and
2021. Whales of Guerrero states that they have launched a 3-year, 6-
site land-based field survey to identify important and vulnerable
nursing and resting sites for humpback whales in Guerrero and are
seeking funds to undertake year-round environmental DNA (eDNA)
collections to determine cetacean usage of Guerrero's waters, coupled
with concurrent boat-based year-round surveys to refine current
understanding of marine mammal species present in Guerrero. Until these
studies have been completed, Whales of Guerrero states that it would be
``irresponsible'' to approve seismic surveys in the region and that in-
depth, year-round research is required to determine species presence
and habitat usage before seismic surveys can safely occur in the
region.
Response: All species referenced by Whales of Guerrero were
included in the table of marine mammals that could occur in the region
(Table 1) in the notice of proposed IHA (87 FR 1992; January 12, 2022)
and in Table 1 of this notice. The abundance and status of all species
in Table 1, as well as the potential effects of L-DEO's activities on
these species, have been considered in our determinations. Whales of
Guerrero did not provide any additional information on these species
that would change our determinations. Additionally, we note that NMFS
does not have the authority to approve the seismic surveys, only the
take of marine mammals incidental to the seismic surveys. NMFS must
grant incidental take authorizations if it can find, based on the best
scientific information available, 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). While Whales
of Guerrero referenced ongoing studies, these studies have not yet been
completed and are not available for NMFS's consideration. The available
information for all species referenced by Whales of Guerrero thus
supports our required findings for authorizing the taking of marine
mammals incidental to L-DEO's planned surveys.
Comment 3: Whales of Guerrero and SOMEMMA stated that Guerrero
lacks the infrastructure to support response to potential marine mammal
strandings and mortality events. Whales of Guerrero further states that
there is no year-round monitoring or stranding response team in place
and the remote locations and difficulty in accessing much of the
coastline would make it unlikely that live stranding events could be
documented and responded to appropriately. Both organizations noted
that scientists and stranding experts from SOMEMMA are planning a
stranding network capacity-building workshop for Guerrero-based
officials, scientists, and local stakeholders in summer of 2022. Whales
of Guerrero recommended seismic surveys in the region not be approved
until a region-wide stranding and monitoring support network is
established.
Response: As stated above, NMFS does not have the authority to
approve the seismic surveys, only the take of marine mammals incidental
to the surveys. We note that L-DEO has conducted seismic surveys around
the world for decades, including in areas without dedicated stranding
networks, and no mass strandings have been reported. As discussed in
the notice of proposed IHA (87 FR 1992; January 12, 2022), stranding is
not expected to result from L-DEO's surveys. In a review of possible
stranding associations with seismic surveys, Castellote and Llorens
(2016) noted one stranding event, involving two Cuvier's beaked whales,
that was contemporaneous with and reasonably associated spatially with
a seismic survey conducted by L-DEO. However, the event was not
considered a ``true atypical mass stranding'' and the L-DEO
[[Page 27113]]
survey was not determined to be a cause of the stranding event. While
we agree with the authors of that review in that lack of evidence
should not be considered conclusive, it is clear that there is very
little evidence that seismic surveys should be considered as posing a
significant risk of acute harm to beaked whales or other mid-frequency
cetaceans. Using the best available information, which does not suggest
that stranding is a likely outcome of the planned surveys, NMFS has
made the necessary findings and is authorizing the incidental take
requested by L-DEO.
Comment 4: Whales of Guerrero and SOMEMMA noted that Guerrero is an
authorized whale watch state in Mexico, with 56 boats and 200 crew
members participating in the whale watch industry. Whales of Guerrero
stated that the whale watch industry and larger community depend on
marine mammal ecotourism, and would be impacted, should the population
of humpback whales, which calve, breed, and nurse in the region be
harmed. The whale watch guide network requested that seismic surveys do
not occur during whale migration season, as threats to whales and
dolphins are a threat to their livelihood.
Response: Again, NMFS does not have the authority to authorize
seismic surveys and will not require L-DEO to change their planned
survey timing to accommodate the whale watch industry. However, since
L-DEO is required to limit its surveys of the ``nearshore'' tracklines
(see definition above) between May 1 and October 31, when migrating
humpbacks are expected to have transited through the area. NMFS has
determined that L-DEO's planned surveys would have a negligible impact
on all species, including the humpback whales that are of particular
interest to the whale watch companies.
Comment 5: Whales of Guerrero and SOMEMMA expressed concern that
the surveys would harm the reputation of the region as environmentally
protective, which would be financially damaging to the area. Both
organizations requested L-DEO discuss the ``potentially harmful''
surveys with regional governmental officials and scientific
organizations which are invested in a healthy marine ecology prior to
conducting survey work in Guerrero.
Response: This comment is outside the scope of our action. L-DEO
conducted all necessary consultations with the Mexican government to
obtain approval to operate in the area.
Comment 6: The CBD stated that the proposed IHA does not include
the best available science regarding humpback whales. The CBD stated
that the proposed IHA says that both the threatened Mexico DPS and
endangered Central America DPS may occur in the proposed survey area,
while the CBD said that humpback whales that winter along the Pacific
coast of southern Mexico off the states of Oaxaca and Guerrero are
likely to be part of the Central America DPS, not the Mexico DPS.
Response: The CBD is correct that the notice of proposed IHA (87 FR
1992; January 12, 2022) stated that humpback whales from both the
Central America DPS and Mexico DPS may occur in the survey area. The
notice further states that due to the expected timing of the surveys
(spring), most humpbacks from the Mexico DPS will have begun their
migration north toward the feeding grounds off of the U.S. west coast
and are likely to be outside of the survey area. Humpbacks from the
Central America DPS will likely be migrating northward through the
survey area at the time of the proposed survey. The notice stated that
we assume that most humpback whales taken by the proposed survey
activities will be from the Central America DPS. NMFS has used the best
available science in assessing the likelihood of each DPS occurring in
the survey area during the planned surveys, and CBD does not offer new
or contradictory information.
Comment 7: The CBD stated that NMFS overestimated the abundance of
the humpback whale population that may be exposed to the surveys. The
CBD referenced Wade (2021) which estimated the abundance of the Central
America DPS of humpback whales to be 755 individuals, while Table 1 in
the notice of proposed IHA gives an abundance estimate of the Central
North Pacific stock of humpback whales as 10,103 individuals. The CBD
asserts that the Central North Pacific stock of humpback whales is the
wrong stock for the area.
Response: As noted by the CBD in previous comment letters (e.g., 86
FR 29090; May 28, 2021), the designated stocks of humpback whales under
the MMPA do not neatly align with the ESA-designated DPSs. Some
humpback whales from the Mexico and Central America DPSs may be part of
the Central North Pacific stock, and some may be part of the
California/Oregon/Washington stock, which has an estimated abundance of
4,973 individuals (Carretta et al., 2021). The abundance of humpback
whales used to assess the relative proportion of the population taken,
which informs our small numbers determination, is the estimated
population of humpbacks in the Pacific waters of Mexico (2,566
individuals; Gerrodette and Palacios, 1996). NMFS has authorized a
total of only 8 takes of humpback whales, which is considered small
numbers relative to any of the aforementioned abundance estimates for
each population.
Comment 8: The CBD asserts that NMFS failed to adequately assess
the impacts of the surveys on the Central America DPS of humpback
whales. The CBD states that the surveys may disrupt breeding activity,
which would have a potential individual effect (i.e., lowering the
individual's reproductive fitness), and a population-level impact by
decreasing the population's ability to grow and recover, referring to a
paper cited by NMFS in the notice of proposed IHA (Cerchio et al.,
2014). The CBD recommended NMFS restrict the authorization to the
summer months to minimize harm to humpback whales.
Response: The paper referenced by the CBD (Cerchio et al., 2014)
describes observations of humpback whales off the coast of Angola
reducing their singing activity when exposed to noise from seismic
surveys. However, the authors of that paper state that it is impossible
to determine from the study whether the decrease in humpback whale
singing would translate into detrimental effects on individuals or the
population. The CBD does not provide any additional evidence to support
its assertion that the effects of L-DEO's proposed activity would have
population-level impacts, or to justify its assertion that the
recommended temporal restriction is warranted under the MMPA. NMFS does
not expect any impacts to the fitness of individual breeding humpback
whales or the population as a whole, regardless of the prescribed
mitigation. However, as described above, Whales of Guerrero informed
NMFS that humpback whales have been observed breeding, calving, and
nursing in the region throughout the spring. Based on the information
provided by Whales of Guerrero, which showed that humpback whale
occurrence in the survey area is generally concentrated in the
nearshore waters, and confirmation on the measure's practicability,
NMFS is adding a requirement to the IHA to limit L-DEO's survey of the
``nearshore'' tracklines until after May 1, at which point all breeding
humpback whales are expected to have left the area, through October 31,
before breeding humpback whales are expected to return to the area.
Therefore, any potential for impacts to the fitness of individual
breeding humpback whales or the
[[Page 27114]]
population as a whole is further reduced.
Comment 9: The CBD urged NMFS to use density estimates for waters
in the area of the survey specifically, rather than in the greater
Eastern Tropical Pacific.
Response: The CBD did not provide any sources for site-specific
density estimates of any species. Therefore, NMFS' utilization of the
density estimates for the greater Eastern Tropical Pacific to estimate
take as the best available science remains valid.
Comment 10: The CBD stated that no one-time, one-year IHA renewal
should be issued without an opportunity for public comment published in
the Federal Register prior to issuance because the timing of the survey
could result in much more severe impacts to Central America humpback
whales if it interrupts more of their breeding season.
Response: As described in the notice of proposed IHA (87 FR 1992;
January 12, 2022), on a case-by-case basis, NMFS may issue a Renewal
IHA following notice to the public providing an additional 15 days for
public comments when (1) up to another year of identical or nearly
identical activities as described in the Description of Proposed
Activity section of the notice of proposed IHA is planned or (2) the
activities as described in the Description of Proposed Activity section
of the notice of proposed IHA would not be completed by the time the
IHA expires and a Renewal would allow for completion of the activities
beyond that described in the Dates section of this notice, provided
specific conditions are met. All proposed Renewal IHAs are posted for
public comment in the Federal Register. Additionally, all parties that
commented on the initial proposed IHA are directly contacted to provide
opportunity to submit additional comments. If L-DEO requests an IHA
Renewal, NMFS will comply with all procedural requirements, including
the 15-day public comment period and notification to the CBD. Any
Renewal IHA issued to L-DEO would include the same mitigation
requirements as the initial IHA, including the timing restrictions
described in the Mitigation section of this notice.
Changes From the Proposed IHA to Final IHA
No changes have been made to the survey equipment, tracklines, or
objectives. The only change from the proposed to final IHA is the
addition of a requirement to limit surveys of ``nearshore'' tracklines
(see definition in the Comments and Responses section and in the
Mitigation section of this notice) between May 1 and October 31.
Description of Marine Mammals in the Area of Specified Activities
Sections 3 and 4 of the 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's Stock Assessment Reports (SARs; <a href="https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessments">https://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's
website (<a href="https://www.fisheries.noaa.gov/find-species">https://www.fisheries.noaa.gov/find-species</a>).
Table 1 lists all species or stocks for which take is expected and
authorized for this action, 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. For taxonomy, we follow Committee on Taxonomy (2021). 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's SARs). While no mortality is
anticipated or authorized here, PBR and annual serious injury and
mortality from anthropogenic sources are included here as gross
indicators of the status of the species 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's 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 managed stocks in this region are assessed in
NMFS's U.S. Pacific SARs. All values presented in Table 1 are the most
recent available at the time of publication and are available in the
2020 SARs (Carretta et al., 2021) and draft 2021 SARs (available online
at: <a href="https://www.fisheries.noaa.gov/national/marine-mammal-protection/draft-marine-mammal-stock-assessment-reports">https://www.fisheries.noaa.gov/national/marine-mammal-protection/draft-marine-mammal-stock-assessment-reports</a>). Where available,
abundance and status information is also presented for marine mammals
in the Pacific waters of Mexico and/or the greater ETP region. Table 1
denotes the status of species and stocks under the U.S. MMPA and ESA.
We note also that the Guadalupe fur seal is classified as ``En peligro
de extinci[oacute]n'' (in danger of extinction) under the Norma Oficial
Mexicana NOM-059-SEMARNAT-2010 and all other marine mammal species
listed in Table 1, with the exception of Longman's beaked whales and
Deraniyagala's beaked whales, are listed as ``Sujetas a
protecci[oacute]n especial'' (subject to special protection).
Table 1--Marine Mammals That Could Occur in the Survey Area
--------------------------------------------------------------------------------------------------------------------------------------------------------
Stock abundance
ESA/MMPA (CV, Nmin, most ETP Mexico
Common name Scientific name Stock status; recent abundance PBR Annual M/ abundance Pacific
strategic survey) \2\ SI \3\ \4\ abundance
(Y/N) \1\ \5\
--------------------------------------------------------------------------------------------------------------------------------------------------------
Order Cetartiodactyla--Cetacea--Superfamily Mysticeti (baleen whales)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Family Balaenopteridae
(rorquals):
Humpback Whale........... Megaptera Central N -, -, Y 10,103 (0.3, 83............... 26 2,566 ...........
novaeangliae. Pacific. 7,890, 2006).
Minke whale.............. Balaenoptera N/A............. -, -, N N/A............. N/A.............. N/A 115 ...........
acutorostrata.
Bryde's whale............ Balaenoptera Eastern Tropical -, -, N Unknown Undetermined..... Unknown 10,411 649
edeni. Pacific. (Unknown,
Unknown, N/A).
Sei whale................ Balaenoptera Eastern N E, D, Y 519 (0.4, 374, 0.75............. >=0.2 0 ...........
borealis. Pacific. 2014).
[[Page 27115]]
Fin whale................ Balaenoptera N/A............. E, D, Y N/A............. N/A.............. N/A 574 145
physalus.
Blue whale............... Balaenoptera Eastern N E, D, Y 1,898 (0.085, 4.1.............. >=19.4 1,415 773
musculus. Pacific. 1,767, 2018).
--------------------------------------------------------------------------------------------------------------------------------------------------------
Superfamily Odontoceti (toothed whales, dolphins, and porpoises)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Family Physeteridae:
Sperm whale.............. Physeter N/A............. E, D, Y N/A............. N/A.............. N/A 4,145 2,810
macrocephalus.
Family Kogiidae:
Dwarf Sperm Whale........ Kogia sima...... N/A............. N/A N/A............. N/A.............. N/A \6\ 11,200 ...........
Family Ziphiidae (beaked
whales):
Cuvier's Beaked Whale.... Ziphius N/A............. -, -, N N/A............. N/A.............. N/A \7\ 20,000 \8\ 68,828
cavirostris.
Longman's beaked whale... Indopacetus N/A............. -, -, N N/A............. N/A.............. N/A 1,007 ...........
pacificus.
Blainville's beaked whale Mesoplodon N/A............. -, -, N N/A............. N/A.............. N/A \9\ 25,300 \8\ 68,828
densirostris.
Ginkgo-toothed beaked M. ginkgodens... N/A............. -, -, N N/A............. N/A.............. N/A \9\ 25,300 \8\ 68,828
whale.
Deraniyagala's beaked M. hotaula...... N/A............. -, -, N N/A............. N/A.............. N/A \9\ 25,300 \8\ 68,828
whale.
Pygmy beaked whale....... M. peruvianus... N/A............. -, -, N N/A............. N/A.............. N/A \9\ 25,300 \8\ 68,828
Family Delphinidae:
Risso's dolphin.......... Grampus griseus. N/A............. -, -, N N/A............. N/A.............. N/A 110,457 24,084
Rough-toothed dolphin.... Steno N/A............. -, -, N N/A............. N/A.............. N/A 107,663 37,511
bredanensis.
Common bottlenose dolphin Tursiops N/A............. -, -, N N/A............. N/A.............. N/A 335,834 61,536
truncatus.
Pantropical spotted Stenella N/A \10\........ -, D, N N/A............. N/A.............. N/A \11\ 146,296
dolphin. attenuata. 1,297,091
Spinner dolphin.......... Stenella N/A \10\........ -, D, N N/A............. N/A.............. N/A \11\ 186,906
longirostris. 2,075,871
Striped dolphin.......... Stenella N/A............. -, -, N N/A............. N/A.............. N/A 964,362 128,867
coeruleoalba.
Short-beaked common Delphinus N/A............. -, -, N N/A............. N/A.............. N/A 3,127,203 283,196
dolphin. delphis.
Fraser's dolphin......... Lagenodelphis N/A............. -, -, N N/A............. N/A.............. N/A \7\ 289,300 ...........
hosei.
Short-finned pilot whale. Globicephala N/A............. -, -, N N/A............. N/A.............. N/A \12\ 3,348
macrorhynchus. 589,315
Killer whale............. Orcinus orca.... N/A............. -, -, N N/A............. N/A.............. N/A \7\ 8,500 852
False killer whale....... Pseudorca N/A............. -, -, N N/A............. N/A.............. N/A \7\ 39,800 ...........
crassidens.
Pygmy killer whale....... Feresa attenuata N/A............. -, -, N N/A............. N/A.............. N/A \7\ 38,900 ...........
Melon-headed whale....... Peponocephala N/A............. -, -, N N/A............. N/A.............. N/A \7\ 45,400 ...........
electra.
--------------------------------------------------------------------------------------------------------------------------------------------------------
Order Carnivora--Superfamily Pinnipedia
--------------------------------------------------------------------------------------------------------------------------------------------------------
Family Otariidae (eared seals
and sea lions):
Guadalupe fur seal....... Arctocephalus Mexico.......... T, D, Y 34,187 (N/A, 1,062............ >=3.8 ........... ...........
townsendi. 31,019, 2013).
California sea lion...... Zalophus U.S............. -, -, N 257,606 (N/ 14,011........... >320 105,000 ...........
californianus. A,233,515,
2014).
--------------------------------------------------------------------------------------------------------------------------------------------------------
\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.fisheries.noaa.gov/national/marine-mammal-protection/draft-marine-mammal-stock-assessment-reports">https://www.fisheries.noaa.gov/national/marine-mammal-protection/draft-marine-mammal-stock-assessment-reports</a>. CV is coefficient of variation; Nmin is the minimum estimate of stock abundance. In some cases, CV is not applicable.
\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.
\4\ From NMFS (2015b) unless otherwise noted.
\5\ Pacific Mexico excluding the Gulf of California (from Gerrodette and Palacios (1996) unless otherwise noted).
\6\ Estimate for ETP is mostly for K. sima but may also include some K. breviceps (Wade and Gerrodette 1993).
\7\ Wade and Gerrodette 1993.
\8\ Abundance for all ziphiids.
\9\ This estimate for the ETP includes all species of the genus Mesoplodon.
\10\ Several stocks of these species, while not classified as such in the U.S. SARs, are considered depleted due to historical interactions with tuna
fisheries in the area. Please see the notice of proposed IHA (87 FR 1992; January 12, 2022) for a discussion of these stocks.
[[Page 27116]]
As indicated above, all 30 species (with six managed stocks) in
Table 1 temporally and spatially co-occur with the activity to the
degree that take is reasonably likely to occur, and we have authorized
it. As the planned survey lines are outside of the U.S. EEZ, they do
not directly overlap with the defined ranges for most U.S. managed
stocks (Carretta et al., 2021). For some species (e.g., Bryde's whale,
Guadalupe fur seal; see Table 1), animals encountered during the
surveys could be from a defined stock under the MMPA but most marine
mammals in the survey area do not belong to any defined stock.
A detailed description of the species likely to be affected by the
geophysical surveys, 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 L-DEO's IHA application and summarized in the Federal
Register notice for the proposed IHA (87 FR 1992; January 12, 2022).
Additional information provided by Whales of Guerrero regarding
seasonal presence of humpback whales is summarized in the Comments and
Responses section above, and their full comment letter is available at
<a href="https://www.fisheries.noaa.gov/national/marine-mammal-protection/incidental-take-authorizations-research-and-other-activities">https://www.fisheries.noaa.gov/national/marine-mammal-protection/incidental-take-authorizations-research-and-other-activities</a>. Since
publication of the notice of proposed IHA, we are not aware of any
changes in ESA or MMPA status of these species or stocks; therefore,
detailed descriptions are not provided here. Please refer to that
Federal Register notice and the IHA application for these descriptions.
Please also refer to NMFS' website (<a href="http://www.nmfs.noaa.gov/pr/species/mammals/">www.nmfs.noaa.gov/pr/species/mammals/</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. Current data indicate that 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) recommended that marine mammals be divided
into functional hearing groups based on directly measured or estimated
hearing ranges on the basis of available behavioral response data,
audiograms derived using auditory evoked potential techniques,
anatomical modeling, and other data. 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).
The pinniped functional hearing group was modified from Southall et
al. (2007) on the basis of data indicating that phocid species have
consistently demonstrated an extended frequency range of hearing
compared to otariids, especially in the higher frequency range
(Hemil[auml] et al., 2006; Kastelein et al., 2009; Reichmuth and Holt,
2013).
For more detail concerning these groups and associated frequency
ranges, please see NMFS (2018) for a review of available information.
30 marine mammal species (28 cetacean and two pinniped (both otariid)
species) have the reasonable potential to co-occur with the planned
survey activities. Please refer to Table 1. Of the cetacean species
that may be present, six are classified as low-frequency cetaceans
(i.e., all mysticete species), 20 are classified as mid-frequency
cetaceans (i.e., all delphinid and ziphiid species and the sperm
whale), and two are classified as high-frequency cetaceans (i.e., Kogia
spp.).
Potential Effects of Specified Activities on Marine Mammals and Their
Habitat
The effects of underwater noise from L-DEO's geophysical survey
activities have the potential to result in behavioral harassment of
marine mammals in the vicinity of the survey area. The notice of
proposed IHA (87 FR 1992; January 12, 2022) included a discussion of
the effects of anthropogenic noise on marine mammals and the potential
effects of underwater noise from L-DEO's geophysical survey activities
on marine mammals and their habitat. That information and analysis is
incorporated by reference into this final IHA determination and is not
repeated here; please refer to the notice of proposed IHA (87 FR 1992;
January 12, 2022). The referenced information includes a summary and
discussion of the ways that the specified activity may impact marine
mammals and their habitat. Consistent with the analysis in our prior
Federal Register notices for similar L-DEO surveys and after
independently evaluating the analysis in L-DEO's application, we
determine that the survey is likely to result in the takes described in
the Estimated Take section of this document and that other forms of
take are not expected to occur.
The Estimated Take section later in this document includes a
quantitative analysis of the number of individuals that are expected to
be taken by this
[[Page 27117]]
activity. The Negligible Impact Analysis and Determination section
considers the content of this section, the Estimated Take section, and
the Mitigation section, to draw conclusions regarding the likely
impacts of these activities on the reproductive success or survivorship
of individuals and how those impacts on individuals are likely to
impact marine mammal species or stocks.
Estimated Take
This section provides an estimate of the number of incidental takes
authorized through this IHA, which will inform both NMFS' consideration
of ``small numbers'' and the negligible impact determination.
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 are primarily by Level B harassment, as use of
seismic airguns has the potential to result in disruption of behavioral
patterns for individual marine mammals. There is also some potential
for auditory injury (Level A harassment) for mysticetes and high
frequency cetaceans (i.e., Kogia spp.). The required mitigation and
monitoring measures are expected to minimize the severity of such
taking to the extent practicable. As described previously, no serious
injury or mortality is anticipated or authorized for this activity.
Below we describe how the take is estimated.
Generally speaking, we estimate take by considering: (1) Acoustic
thresholds above which NMFS believes the best available science
indicates marine mammals will be behaviorally harassed or incur some
degree of permanent hearing impairment; (2) the area or volume of water
that will be ensonified above these levels in a day; (3) the density or
occurrence of marine mammals within these ensonified areas; and, (4)
the number of days of activities. We note that while these basic
factors can contribute to a basic calculation to provide an initial
prediction of 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 estimate.
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 for non-explosive sources--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 (e.g., frequency, predictability,
duty cycle), the environment (e.g., bathymetry), and the receiving
animals (hearing, motivation, experience, demography, behavioral
context) and can be difficult to predict (Southall et al., 2007,
Ellison et al., 2012). Based on what the available science indicates
and the practical need to use a threshold based on a factor that is
both predictable and measurable for most activities, NMFS uses a
generalized acoustic threshold based on received level to estimate the
onset of behavioral harassment. NMFS predicts that marine mammals are
likely to be behaviorally harassed in a manner we consider Level B
harassment when exposed to underwater anthropogenic noise above
received levels of 120 dB re 1 microPascal ([mu]Pa) root mean square
(rms) for continuous (e.g., vibratory pile-driving, drilling) and above
160 dB re 1 [mu]Pa (rms) for non-explosive impulsive (e.g., seismic
airguns) or intermittent (e.g., scientific sonar) sources.
L-DEO's activity includes the use of impulsive seismic sources, and
therefore the 160 dB re 1 [mu]Pa (rms) threshold is applicable.
Level A harassment for non-explosive sources--NMFS' Technical
Guidance for Assessing the Effects of Anthropogenic Sound on Marine
Mammal Hearing (Version 2.0) (Technical Guidance, 2018) identifies dual
criteria to assess auditory injury (Level A harassment) to five
different marine mammal groups (based on hearing sensitivity) as a
result of exposure to noise from two different types of sources
(impulsive or non-impulsive). L-DEO's planned seismic survey includes
the use of impulsive (seismic airguns) sources.
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="https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-acoustic-technical-guidance">https://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: 219 dB; Cell 2: LE,LF,24h: 199 dB.
LE,LF,24h: 183 dB.
Mid-Frequency (MF) Cetaceans........... Cell 3: Lpk,flat: 230 dB; Cell 4: LE,MF,24h: 198 dB.
LE,MF,24h: 185 dB.
High-Frequency (HF) Cetaceans.......... Cell 5: Lpk,flat: 202 dB; Cell 6: LE,HF,24h: 173 dB.
LE,HF,24h: 155 dB.
Phocid Pinnipeds (PW).................. Cell 7: Lpk,flat: 218 dB; Cell 8: LE,PW,24h: 201 dB.
(Underwater)........................... LE,PW,24h: 185 dB.
Otariid Pinnipeds (OW)................. Cell 9: Lpk,flat: 232 dB; Cell 10: LE,OW,24h: 219 dB.
(Underwater)........................... LE,OW,24h: 203 dB.
----------------------------------------------------------------------------------------------------------------
* Dual metric acoustic thresholds for impulsive sounds: Use whichever results in the largest isopleth for
calculating PTS onset. If a non-impulsive sound has the potential of exceeding the peak sound pressure level
thresholds associated with impulsive sounds, these thresholds should also be considered.
[[Page 27118]]
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 will feed into identifying the area ensonified above the
acoustic thresholds, which include source levels and transmission loss
coefficient.
The planned 2-D survey would acquire data using the 36-airgun array
with a total discharge of 6,600 in\3\ at a maximum tow depth of 12 m.
L-DEO model results are used to determine the 160-dBrms radius for the
36-airgun array in deep water (>1,000 m) down to a maximum water depth
of 2,000 m. Received sound levels were predicted by L-DEO's model
(Diebold et al., 2010) which 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 (approximately 1600 m), intermediate water depth
on the slope (approximately 600-1100 m), and shallow water
(approximately 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 Level A and Level B harassment
isopleths, as at those sites the calibration hydrophone was located at
a roughly constant depth of 350-500 m, which may not intersect all the
SPL isopleths at their widest point from the sea surface down to the
maximum relevant water depth for marine mammals of ~2,000 m. At short
ranges, where the direct arrivals dominate and the effects of seafloor
interactions are minimal, the data recorded at the deep and slope 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, comparisons at short ranges
between sound levels for direct arrivals recorded by the calibration
hydrophone and model results for the same array tow depth are in good
agreement (Fig. 12 and 14 in Appendix H of NSF-USGS, 2011).
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. 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.
For deep water (>1,000 m), L-DEO used the deep-water radii obtained
from model results down to a maximum water depth of 2000 m. The radii
for intermediate water depths (100-1,000 m) were 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 Fig. 16 in Appendix H of NSF-USGS, 2011).
L-DEO's modeling methodology is described in greater detail in
their IHA application. The estimated distances to the Level B
harassment isopleths for the array are shown in Table 4. Please note
that no survey effort will occur in waters <100 m deep. The estimated
isopleth distance specific to shallow water depths are provided for
reference only.
Table 4--Predicted Radial Distances to Isopleths Corresponding to Level B Harassment Threshold
----------------------------------------------------------------------------------------------------------------
Level B
Source and volume Tow depth (m) Water depth harassment
(m) zone (m)
----------------------------------------------------------------------------------------------------------------
36 airgun array; 6,600 in \3\................................... 12 >1,000 \1\ 6,733
100-1,000 \2\ 10,100
<100 \3\ \4\ 25,494
----------------------------------------------------------------------------------------------------------------
\1\ Distance based on L-DEO model results.
\2\ Distance is based on L-DEO model results with a 1.5 x correction factor between deep and intermediate water
depths.
\3\ No survey effort will occur in waters <100 m deep.
\4\ Distance is based on empirically derived measurements in the Gulf of Mexico with scaling applied to account
for differences in tow depth.
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 source modeling 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 metrics (NMFS
2018). 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
[[Page 27119]]
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 values for SEL<INF>cum</INF> and peak SPL for the Langseth
airgun arrays were derived from calculating the modified far-field
signature. The far-field signature is often used as a theoretical
representation of the source level. To compute the far-field signature,
the source level is estimated at a large distance 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,
when the source is an array of multiple airguns separated in space, the
source level from the theoretical far-field signature is not
necessarily the best measurement of the source level that is physically
achieved at the source (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 far-field signature. The pulses from the
different airguns spread out in time such that the source levels
observed or modeled are the result of the summation of pulses from a
few airguns, not the full array (Tolstoy et al., 2009). At larger
distances, away from the source array center, sound pressure of all the
airguns in the array stack coherently, but not within one time sample,
resulting in smaller source levels (a few dB) than the source level
derived from the far-field signature. Because the far-field signature
does not take into account the large array effect near the source and
is calculated as a point source, the modified far-field signature is a
more appropriate measure of the sound source level for distributed
sound sources, such as airgun arrays. L-DEO used the acoustic modeling
methodology as used for estimating Level B harassment distances with a
small grid step of 1 m in both the inline and depth directions. The
propagation modeling takes into account all airgun interactions at
short distances from the source, including interactions between
subarrays, which are modeled using the NUCLEUS software to estimate the
notional signature and MATLAB software to calculate the pressure signal
at each mesh point of a grid.
In order to more realistically incorporate the Technical Guidance's
weighting functions over the seismic array's full acoustic band,
unweighted spectrum data for the Langseth's airgun array (modeled in 1
Hz bands) was used to make adjustments (dB) to the unweighted spectrum
levels, by frequency, according to the weighting functions for each
relevant marine mammal hearing group. These adjusted/weighted spectrum
levels were then converted to pressures ([mu]Pa) in order to integrate
them over the entire broadband spectrum, resulting in broadband
weighted source levels by hearing group that could be directly
incorporated within the User Spreadsheet (i.e., to override the
Spreadsheet's more simple weighting factor adjustment). Using the User
Spreadsheet's ``safe distance'' methodology for mobile sources
(described by Sivle et al., 2014) with the hearing group-specific
weighted source levels, and inputs assuming spherical spreading
propagation and information specific to the planned survey (i.e., the
2.2 m/s source velocity and (worst-case) 50-m shot interval, equivalent
to a repetition rate of 23.1 seconds), potential radial distances to
auditory injury zones were then calculated for SEL<INF>cum</INF>
thresholds.
Inputs to the User Spreadsheets in the form of estimated source
levels are shown in Appendix A of L-DEO's application. User
Spreadsheets used by L-DEO to estimate distances to Level A harassment
isopleths for the airgun arrays are also provided in Appendix A of the
application. Outputs from the User Spreadsheets in the form of
estimated distances to Level A harassment isopleths for the survey are
shown in Table 5. As described above, NMFS considers onset of PTS
(Level A harassment) to have occurred when either one of the dual
metrics (SEL<INF>cum</INF> and Peak SPL<INF>flat</INF>) is exceeded
(i.e., metric resulting in the largest isopleth). L-DEO plans to
conduct two different methods of seismic acquisition, MCS using a
hydrophone streamer (approximately 62 percent of the total survey
effort) and refraction surveys using OBSs (approximately 38 percent of
the total survey effort). The airguns would fire at a shot interval of
50 m (repetition rate of 23 seconds) during MCS surveys and at a 400-m
interval (repetition rate of 155 seconds) during refraction surveys to
OBSs. The distances presented in Table 5 were calculated using the MCS
survey inputs as using the 50-m shot interval provides more
conservative distances than the 400-m shot interval.
Table 5--Modeled Radial Distances (m) to Isopleths Corresponding to Level A Harassment Thresholds
----------------------------------------------------------------------------------------------------------------
Level A harassment zone (m)
Source (volume) Threshold ---------------------------------------------------------------
LF cetaceans MF cetaceans HF cetaceans Otariids
----------------------------------------------------------------------------------------------------------------
36-airgun array (6,600 in\3\). SELcum.......... 320.2 0 1.0 0
Peak............ 8.9 13.9 268.3 10.6
----------------------------------------------------------------------------------------------------------------
Note that because of some of the assumptions included in the
methods used (e.g., stationary receiver with no vertical or horizontal
movement in response to the acoustic source), isopleths produced may be
overestimates to some degree, which will ultimately result in some
degree of overestimation of Level A harassment. However, these tools
offer the best way to predict appropriate isopleths when more
sophisticated modeling methods are not available, and NMFS continues to
develop ways to quantitatively refine these tools and will
qualitatively address the output where appropriate. For mobile sources,
such as the planned seismic survey, the User Spreadsheet predicts the
closest distance at which a stationary animal would not incur PTS if
the sound source traveled by the animal in a straight line at a
constant speed.
Auditory injury is unlikely to occur for mid-frequency cetaceans
and otariid pinnipeds, given very small modeled zones of injury for
those species (all estimated zones less than 15 m for mid-frequency
cetaceans and otariid pinnipeds), 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
[[Page 27120]]
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 would in all cases be
expected to be within the near-field of the array where the definition
of source level breaks down. Therefore, actual locations within this
distance of the array center where the sound level exceeds the relevant
peak SPL thresholds would not necessarily exist. In general, Caldwell
and Dragoset (2000) suggest that the near-field for airgun arrays is
considered to extend out to approximately 250 m.
In order to provide quantitative support for this theoretical
argument, we calculated expected maximum distances at which the near-
field would transition to the far-field (Table 5). For a specific array
one can estimate the distance at which the near-field transitions to
the far-field by:
[GRAPHIC] [TIFF OMITTED] TN06MY22.025
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] TN06MY22.026
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] TN06MY22.027
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/far-field
calculations for airgun arrays (Zykov and Carr, 2014; MacGillivray,
2006; NSF and USGS, 2011), and based on representative airgun spectrum
data and field measurements of an airgun array used on the Langseth,
nearly all (greater than 95 percent) of the energy from airgun arrays
is below 1 kHz (Tolstoy et al., 2009). Thus, using 1 kHz as the upper
cut-off for calculating the maximum extent of the near-field should
reasonably represent the near-field extent in field conditions.
If the largest distance to the peak sound pressure level threshold
was equal to or less than the longest dimension of the array (i.e.,
under the array), or within the near-field, then received levels that
meet or exceed the threshold in most cases are not expected to occur.
This is because within the near-field and within the dimensions of the
array, the source levels specified in Appendix A of L-DEO's application
are overestimated and not applicable. In fact, until one reaches a
distance of approximately three or four times the near-field distance
the average intensity of sound at any given distance from the array is
still less than that based on calculations that assume a directional
point source (Lurton, 2002). The 6,600-in\3\ airgun array planned for
use during the planned survey has an approximate diagonal of 28.8 m,
resulting in a near-field distance of 138.7 m at 1 kHz (NSF and USGS,
2011). Field measurements of this array indicate that the source
behaves like multiple discrete sources, rather than a directional point
source, beginning at approximately 400 m (deep site) to 1 km (shallow
site) from the center of the array (Tolstoy et al., 2009), distances
that are actually greater than four times the calculated 140-m near-
field distance. Within these distances, the recorded received levels
were always lower than would be predicted based on calculations that
assume a directional point source, and increasingly so as one moves
closer towards the array (Tolstoy et al., 2009). Given this, relying on
the calculated distance (138.7 m) as the distance at which we expect to
be in the near-field is a conservative approach since even beyond this
distance the acoustic modeling still overestimates the actual received
level. Within the near-field, in order to explicitly evaluate the
likelihood of exceeding any particular acoustic threshold, one would
need to consider the exact position of the animal, its relationship to
individual array elements, and how the individual acoustic sources
propagate and their acoustic fields interact. Given that within the
near-field and dimensions of the array source levels would be below
those assumed here, we believe exceedance of the peak pressure
threshold would only be possible under highly unlikely circumstances.
In consideration of the received sound levels in the near-field as
described above, we expect the potential for Level A harassment of mid-
frequency cetaceans, otariid pinnipeds, and phocid pinnipeds to be de
minimis, even before the likely moderating effects of aversion and/or
other compensatory behaviors (e.g., Nachtigall et al., 2018) are
considered. We do not believe that Level A harassment is a likely
outcome for any mid-frequency cetacean, otariid pinniped, or phocid
pinniped and have not authorized any Level A harassment for these
species.
Marine Mammal Occurrence
In this section we provide the information about the presence,
density, or group dynamics of marine mammals that will inform the take
calculations.
L-DEO used habitat-based stratified marine mammal densities for
summer for the ETP when available (Barlow et al., 2009), and densities
for the ETP from NMFS (2015b) for all other species (Table 6). Barlow
et al. (2009) used data from 16 NMFS Southwest Fisheries Science Center
(SWFSC) ship-based cetacean and ecosystem assessment surveys between
1986 and 2006 to develop habitat models to predict density for 15
cetacean species in the ETP. Model predictions were then used in
standard line-transect formulae to estimate density for each transect
segment for each survey year. Predicted densities for each year were
smoothed with geospatial methods to obtain a continuous grid of density
estimates for the surveyed area in the ETP. These annual grids were
then averaged to obtain a composite grid that represents our best
estimates of cetacean density over the past 20 years in the ETP. The
models developed by Barlow et al. (2009) have been incorporated into a
web-based GIS software system developed by Duke University's Strategic
Environmental Research and Development Program. The habitat-based
density models consist of 100 km x 100 km grid cells. Densities in the
grid cells that overlapped the survey area were averaged for each of
the three water depth categories (shallow, intermediate, deep).
The NMFS SWFSC also developed density estimates for species in the
ETP that may be affected by their own
[[Page 27121]]
fisheries research activities (NMFS 2015b). These estimates were
derived from abundance estimates using ship-based surveys of marine
mammals in the ETP, as reported by Gerrodette et al. (2008). While the
SWFSC developed volumetric density estimates (animals/km\3\) to account
for typical dive depth of each species (0-200 m and >200 m), L-DEO used
the area density (animals/km\2\) to represent expected density across
all water depth strata.
For the sei whale, for which NMFS (2015b) reported a density of
zero, L-DEO used the spring density for Baja from U.S. Navy (2017b). No
regional density estimates are available for Guadalupe fur seals in the
ETP; therefore, NMFS (2015b) used the density of Guadalupe fur seals in
the California Current Ecosystem (CCE) as a proxy. However, as the
survey area is south of the typical range of Guadalupe fur seals (Ortiz
et al., 2019), the density from the CCE is likely an overestimate. In
the survey area, Guadalupe fur seals are extremely unlikely to occur in
waters over the continental shelf under 2,000 m (T. Norris, pers.
comm.). NMFS has therefore assumed that the density of Guadalupe fur
seals in water depths under 2,000 m is zero animals per square km, and
have retained the CCE density estimate for waters over 2,000 m deep
(Table 6).
Table 6--Estimated Densities of Marine Mammals in the Survey Area
----------------------------------------------------------------------------------------------------------------
Density (#/km\2\) in survey area
--------------------------------------------------------
Species Intermediate
Shallow water water (100-1,000 Deep water
(<100 m) m) (>1,000 m)
----------------------------------------------------------------------------------------------------------------
Humpback whale......................................... \1\ 0.00013 \1\ 0.00013 \1\ 0.00013
Minke whale............................................ \1\ 0.00001 \1\ 0.00001 \1\ 0.00001
Bryde's whale.......................................... \2\ 0.000486 \2\ 0.000489 \2\ 0.000451
Fin whale.............................................. \1\ 0.00003 \1\ 0.00003 \1\ 0.00003
Sei whale.............................................. \3\ 0.00005 \3\ 0.00005 \3\ 0.00005
Blue whale............................................. \2\ 0.00010 \2\ 0.00009 \2\ 0.00008
Sperm whale............................................ \1\ 0.00019 \1\ 0.00019 \1\ 0.00019
Cuvier's beaked whale.................................. \2\ 0.00105 \2\ 0.00106 \2\ 0.00107
Longman's beaked whale................................. \1\ 0.00004 \1\ 0.00004 \1\ 0.00004
Mesoplodon spp.\4\..................................... \2\ 0.00032 \2\ 0.00033 \2\ 0.00036
Risso's dolphin........................................ \1\ 0.00517 \1\ 0.00517 \1\ 0.00517
Rough-toothed dolphin.................................. \2\ 0.00880 \2\ 0.00891 \2\ 0.00945
Common bottlenose dolphin.............................. \2\ 0.04809 \2\ 0.04502 \2\ 0.03557
Pantropical spotted dolphin............................ \1\ 0.12263 \1\ 0.12263 \1\ 0.12263
Spinner dolphin (whitebelly)........................... \2\ 0.00148 \2\ 0.00155 \2\ 0.00193
Spinner dolphin (eastern).............................. \2\ 0.13182 \2\ 0.12989 \2\ 0.12791
Striped dolphin........................................ \2\ 0.02800 \2\ 0.02890 \2\ 0.03516
Short-beaked common dolphin............................ \2\ 0.04934 \2\ 0.04881 \2\ 0.04435
Fraser's dolphin....................................... \1\ 0.01355 \1\ 0.01355 \1\ 0.01355
Short-finned pilot whale \5\........................... \2\ 0.00346 \2\ 0.00344 \2\ 0.00382
Killer whale........................................... \1\ 0.0004 \1\ 0.0004 \1\ 0.0004
False killer whale..................................... \1\ 0.00186 \1\ 0.00186 \1\ 0.00186
Pygmy killer whale..................................... \1\ 0.00183 \1\ 0.00183 \1\ 0.00183
Melon-headed whale..................................... \1\ 0.00213 \1\ 0.00213 \1\ 0.00213
Kogia spp.............................................. \1\ 0.00053 \1\ 0.00053 \1\ 0.00053
Guadalupe fur seal..................................... 0 \1\ \6\ 0.00741 \1\ 0.00741
California sea lion.................................... \1\ 0.16262 \1\ 0.16262 \7\ 0
----------------------------------------------------------------------------------------------------------------
\1\ Density in greater ETP (NMFS 2015b).
\2\ Density in planned survey area (Barlow et al., 2009).
\3\ Density for Baja (U.S. Navy 2017b).
\4\ Density for Mesoplodon species guild (Blainville's beaked whale, Gingko-toothed beaked whale, Deraniyagala's
beaked whale, and pygmy beaked whale).
\5\ Density for Globicephala species guild.
\6\ Density is assumed to be zero in waters <2,000 m.
\7\ Density is assumed to be zero in deep water (>1,000 m).
Take Calculation and Estimation
Here we describe how the information provided above is brought
together to produce a quantitative take estimate.
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 predicted
isopleths 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 Level
A and Level B harassment thresholds. L-DEO identified specific seismic
survey trackline(s) that could be surveyed on one day of research; in
this case, a representative 182-km MCS line and a 222-km long OBS line
were chosen. The distances to the 160-dB Level B harassment threshold
and PTS (Level A harassment) thresholds (based on L-DEO model results)
were used to draw a buffer around every transect line in GIS to
determine the daily ensonified area in each depth category. The
ensonified areas were then multiplied by the number of survey days (7
days for OBS survey effort; 13 days for MCS survey effort) increased by
25 percent. As noted previously, L-DEO has added 25 percent in the form
of operational days, which is equivalent to adding 25 percent to the
planned line kilometers to be surveyed. This accounts for the
possibility that additional operational days are required, but likely
results in an overestimate of actual exposures. For additional details
regarding calculations of ensonified area, please see Appendix D of L-
DEO's application. L-DEO's estimated incidents of exposure above Level
A and Level B harassment criteria are presented in Table 7.
[[Page 27122]]
As previously noted, NMFS does not have authority under the MMPA
within the territorial seas of foreign nations (from 0-12 nmi (22.2 km)
from shore), as the MMPA does not apply in those waters, and therefore
does not authorize incidental take that may occur as a result of
activities occurring within territorial waters. However, NMFS has still
calculated the estimated level of incidental take in the entire
activity area (including Mexican territorial waters) as part of the
analysis supporting our determination under the MMPA that the activity
will have a negligible impact on the affected species. The total
estimated take in U.S. and Mexican waters is presented in Table 8 (see
Negligible Impact Analysis and Determination).
L-DEO generally assumed that their estimates of marine mammal
exposures above harassment thresholds to equate to take and requested
authorization of those takes. Those estimates in turn form the basis
for our take authorization numbers. For the species for which NMFS does
not expect there to be a reasonable potential for take by Level A
harassment to occur, i.e., mid-frequency cetaceans and all pinnipeds,
we have added L-DEO's estimated exposures above Level A harassment
thresholds (and requests for take by Level A harassment) to their
estimated exposures above the Level B harassment threshold to produce a
total number of incidents of take by Level B harassment that is
authorized. Estimated exposures and authorized take numbers are shown
in Table 7.
Table 7--Estimated and Authorized Take by Level A and Level B Harassment, and Percentage of Population
--------------------------------------------------------------------------------------------------------------------------------------------------------
Estimated Estimated Authorized Authorized Total Regional
Species takes by Level takes by Level takes by Level takes by Level authorized population Percent of
B harassment A harassment B harassment A harassment take size population
--------------------------------------------------------------------------------------------------------------------------------------------------------
Humpback whale.......................... 8 0 8 0 8 \a\ 2,566 0.31
Minke whale............................. 1 0 \b\ 2 0 \b\ 2 115 1.74
Bryde's whale........................... 27 1 27 1 28 \a\ 649 4.31
Fin whale............................... 2 0 2 0 2 \a\ 145 1.38
Sei whale............................... 3 0 3 0 3 \c\ 29,600 0.01
Blue whale.............................. 5 0 5 0 5 773 0.65
Sperm whale............................. 12 0 12 0 12 2,810 0.43
Cuvier's beaked whale................... 69 0 69 0 69 \c\ 20,000 0.35
Longman's beaked whale.................. 3 0 3 0 3 \c\ 1,007 0.30
Mesoplodon spp.......................... 23 0 23 0 23 \c\ 25,300 0.09
Risso's dolphin......................... 327 1 328 0 328 \a\ 24,084 1.36
Rough-toothed dolphin................... 596 1 597 0 597 \a\ 37,511 1.59
Common bottlenose dolphin............... 2,268 6 2,274 0 2,274 \a\ 61,536 3.70
Pantropical spotted dolphin............. 7,973 15 7,988 0 7,988 \a\ 146,296 5.46
Spinner dolphin (whitebelly)............ 121 0 121 0 121 \a\ 186,906 0.06
Spinner dolphin (eastern)............... 8,173 16 8,189 0 8,189 \a\ 186,906 4.38
Striped dolphin......................... 2,209 3 2,212 0 2,212 \a\ 128,867 1.72
Short-beaked common dolphin............. 2,812 6 2,818 0 2,818 \a\ 283,196 1.00
Fraser's dolphin........................ 856 2 858 0 858 \c\ 289,300 0.30
Short-finned pilot whale................ 244 0 244 0 244 \a\ 3,348 7.29
Killer whale............................ 25 0 25 0 25 \a\ 852 2.93
False killer whale...................... 118 0 118 0 118 \c\ 39,600 0.30
Pygmy killer whale...................... 116 0 116 0 116 \c\ 38,900 0.30
Melon-headed whale...................... 135 0 135 0 135 \c\ 45,400 0.30
Kogia spp............................... 33 1 33 1 34 \c\ \d\ 11,200 0.30
Guadalupe fur seal...................... 415 1 416 0 416 \c\ 34,187 1.22
California sea lion..................... 349 16 365 0 365 \c\ 105,000 0.35
--------------------------------------------------------------------------------------------------------------------------------------------------------
\a\ Estimated population in Pacific waters of Mexico (Gerrodette and Palacios (1996)).
\b\ Authorized take increased to maximum group size.
\c\ Population in ETP or wider Pacific (NMFS 2015b).
\d\ Population of Kogia species guild.
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, we
carefully consider 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.
This considers the nature of the potential adverse impact being
mitigated (likelihood,
[[Page 27123]]
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, impact on
operations, and, in the case of a military readiness activity,
personnel safety, practicality of implementation, and impact on the
effectiveness of the military readiness activity.
In order to satisfy the MMPA's least practicable adverse impact
standard, NMFS has evaluated a suite of basic mitigation protocols for
seismic surveys that are required regardless of the status of a stock.
Additional or enhanced protections may be required for species whose
stocks are in particularly poor health and/or are subject to some
significant additional stressor that lessens that stock's ability to
weather the effects of the specified activities without worsening its
status. We reviewed seismic mitigation protocols required or
recommended elsewhere (e.g., HESS, 1999; DOC, 2013; IBAMA, 2018; Kyhn
et al., 2011; JNCC, 2017; DEWHA, 2008; BOEM, 2016; DFO, 2008; GHFS,
2015; MMOA, 2016; Nowacek et al., 2013; Nowacek and Southall, 2016),
recommendations received during public comment periods for previous
actions, and the available scientific literature. We also considered
recommendations given in a number of review articles (e.g., Weir and
Dolman, 2007; Compton et al., 2008; Parsons et al., 2009; Wright and
Cosentino, 2015; Stone, 2015b). This exhaustive review and
consideration of public comments regarding previous, similar activities
has led to development of the protocols included here.
Vessel-Based Visual Mitigation Monitoring
Visual monitoring requires the use of trained observers (herein
referred to as visual protected species observers (PSOs)) to scan the
ocean surface for the presence of marine mammals. The area to be
scanned visually includes primarily the exclusion zone (EZ), 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 EZ to be monitored for the presence of marine
mammals that may enter the EZ. During pre-start clearance monitoring
(i.e., before ramp-up begins), the buffer zone also acts as an
extension of the EZ in that observations of marine mammals within the
buffer zone would also prevent airgun operations from beginning (i.e.,
ramp-up). The buffer zone encompasses the area at and below the sea
surface from the edge of the 0-500 m EZ, out to a radius of 1,000 m
from the edges of the airgun array (500-1,000 m). This 1,000-m zone (EZ
plus buffer) represents the pre-start clearance zone. Visual monitoring
of the EZ 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 EZ by alerting the visual observer and crew of marine
mammals that are outside of, but may approach and enter, the EZ.
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 must be designated as the lead for the
entire protected species observation team. The lead PSO must 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 must 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 one hour after use of the acoustic
source ceases or until 30 minutes past sunset. Visual PSOs must
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 must establish and monitor the exclusion and buffer zones.
These zones must 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 EZ) must be
communicated to the operator to prepare for the potential shutdown of
the acoustic source. Visual PSOs must 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 must be relayed to the
PSO team. During good conditions (e.g., daylight hours; Beaufort sea
state (BSS) 3 or less), visual PSOs must 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 one 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
Acoustic monitoring means the use of trained personnel (sometimes
referred to as passive acoustic monitoring (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
[[Page 27124]]
daylight hours) in maintaining an EZ 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 must take place in addition to the visual monitoring program.
Visual monitoring typically is not effective during periods of poor
visibility or at night, and even with good visibility, is unable to
detect marine mammals when they are below the surface or beyond visual
range. Acoustic monitoring can be used in addition to visual
observations to improve detection, identification, and localization of
cetaceans. The acoustic monitoring would serve to alert visual PSOs (if
on duty) when vocalizing cetaceans are detected. It is only useful when
marine mammals vocalize, but it can be effective either by day or by
night, and does not depend on good visibility. It must be monitored in
real time so that the visual observers can be advised when cetaceans
are detected.
The R/V Langseth must 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 one 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.
Establishment of Exclusion and Pre-Start Clearance Zones
An EZ 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 must establish a minimum EZ with a 500-m radius. The 500-m EZ must
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 must 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 EZ plus the buffer zone. Detections of marine
mammals within the pre-start clearance zone must prevent airgun
operations from beginning (i.e., ramp-up).
The 500-m EZ is intended to be precautionary in the sense that it
would be expected to contain sound exceeding the injury criteria for
all cetacean hearing groups, (based on the dual criteria of
SEL<INF>cum</INF> and peak SPL), while also providing a consistent,
reasonably observable zone within which PSOs would typically be able to
conduct effective observational effort. Additionally, a 500-m EZ 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 EZ, doubling the EZ size during pre-clearance.
An extended EZ of 1,500 m must be enforced for all beaked whales
and Kogia species. No buffer of this extended EZ 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 must
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 EZ, 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 would prevent operations (i.e., the beginning of
ramp-up). The intent of ramp-up is to warn marine mammals of pending
seismic survey operations and to allow sufficient time for those
animals to leave the immediate vicinity. 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 must 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 EZ) for 30 minutes prior to the initiation of ramp-up
(pre-start clearance);
<bullet> Ramp-ups must 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 exclusion or buffer zone. If a marine mammal is
observed within the pre-start clearance zone (or extended EZ, 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
pinnipeds, and 30 minutes for all mysticetes and all other odontocetes,
including sperm whales, beaked whales, and large delphinids, such as
killer whales);
<bullet> Ramp-up must 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 must not be
less than 20 minutes. The operator must
[[Page 27125]]
provide information to the PSO documenting that appropriate procedures
were followed;
<bullet> PSOs must monitor the pre-start clearance zone (and
extended EZ) 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 must 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 EZ. 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 EZ. 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 must be
immediately communicated to the remainder of the on-duty PSO team for
potential verification of visual observations by the acoustic PSO or of
acoustic detections by visual PSOs. When the airgun array is active
(i.e., anytime one or more airguns is active, including during ramp-up)
and (1) a marine mammal appears within or enters the applicable EZ and/
or (2) a marine mammal (other than delphinids, see below) is detected
acoustically and localized within the applicable EZ, the acoustic
source must be shut down. When shutdown is called for by a PSO, the
acoustic source must be immediately deactivated and any dispute
resolved only following deactivation. Additionally, shutdown must occur
whenever PAM alone (without visual sighting), confirms presence of
marine mammal(s) in the EZ. If the acoustic PSO cannot confirm presence
within the EZ, visual PSOs must be notified but shutdown is not
required.
Following a shutdown, airgun activity must not resume until the
marine mammal has cleared the EZ. The animal is considered to have
cleared the EZ if it is visually observed to have departed the EZ
(i.e., animal is not required to fully exit the buffer zone where
applicable), or it has not been seen within the EZ for 15 minutes for
small odontocetes and pinnipeds, or 30 minutes for all mysticetes and
all other odontocetes, including sperm whales, beaked whales, Kogia
species, and large delphinids, such as killer whales.
The shutdown requirement is waived for small dolphins if an
individual is detected within the EZ. 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,
Lissodelphis, Stenella, Steno, and Tursiops).
We include this small dolphin exception because shutdown
requirements for small dolphins under all circumstances represent
practicability concerns without likely commensurate benefits for the
animals in question. Small dolphins are generally the most commonly
observed marine mammals in the specific geographic region and would
typically be the only marine mammals likely to intentionally approach
the vessel. As described above, auditory injury is extremely unlikely
to occur for 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 would require the Langseth to revisit the missed track line to
reacquire data, resulting in an overall increase in the total sound
energy input to the marine environment and an increase in the total
duration over which the survey is active in a given area. Although
other 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 would not have similar impacts in
terms of either practicability for the applicant or corollary increase
in sound energy output and time on the water. We do anticipate some
benefit for a shutdown requirement for large delphinids in that it
simplifies somewhat the total range of decision-making for PSOs and may
preclude any potential for physiological effects other than to the
auditory system as well as some more severe behavioral reactions for
any such animals in close proximity to the Langseth.
Visual PSOs must 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 EZ).
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.
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
[[Page 27126]]
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 to
identify a marine mammal as a whale or other marine mammal.
Vessel speeds must be reduced to 10 knots 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 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 must 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.
Operational Restrictions
L-DEO has agreed to limit surveys of all ``nearshore'' tracklines
(i.e., tracklines occurring in, or which are anticipated to result in
ensonification above the Level B harassment threshold of, areas where
humpback whale sightings have been recorded during the migratory
period, e.g., the 264-km MCS and OBS trackline nearest and parallel to
the shoreline, and all lines landward of that trackline) to between May
1 and October 31. Offshore tracklines may be surveyed outside that date
range. This is included as a requirement of the IHA.
We have carefully evaluated the suite of mitigation measures
described here and considered a range of other measures in the context
of ensuring that we prescribe the means of effecting the least
practicable adverse impact on the affected marine mammal species and
stocks and their habitat. Based on our evaluation of the required
measures, as well as other measures considered by NMFS described above,
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.
Mitigation Measures in Mexican Waters
As stated previously, NMFS cannot authorize the incidental take of
marine mammals in the territorial seas of foreign nations, as the MMPA
does not apply in those waters. L-DEO is required to adhere to the
mitigation measures described above while operating within the Mexican
EEZ and International Waters. The requirements do not apply within
Mexican territorial waters. Mexico may prescribe mitigation measures
that would apply to survey operations within the Mexican EEZ and
territorial waters but NMFS is currently unaware of any specific
potential requirements. While operating within the Mexican EEZ but
outside Mexican territorial waters, if mitigation requirements
prescribed by NMFS differ from the requirements established under
Mexican law, L-DEO must adhere to the most protective measure. For
operations in Mexican territorial waters, L-DEO would implement
measures required under Mexican law (if any). No new information is
available on mitigation measures required under Mexican law.
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 in the
survey area. 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 action; 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).
<bullet> Mitigation and monitoring effectiveness.
Vessel-Based Visual Monitoring
As described above, PSO observations must take place during daytime
airgun operations. During seismic survey operations, at least five
visual PSOs must be based aboard the Langseth. Two visual PSOs must be
on duty at all time during daytime hours. Monitoring must be conducted
in accordance with the following requirements:
<bullet> The operator must 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 must 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 must 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
[[Page 27127]]
distance and bearing to observed marine mammals.
PSOs must have the following requirements and qualifications:
<bullet> PSOs must be independent, dedicated, trained visual and
acoustic PSOs and must be employed by a third-party observer provider;
<bullet> PSOs must 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 must 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 must demonstrate good standing and
consistently good performance of PSO duties.
For data collection purposes, PSOs must use standardized data
collection forms, whether hard copy or electronic. PSOs must 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 implemented, PSOs must 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 must 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 must 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.
[[Page 27128]]
Reporting
A report must be submitted to NMFS within 90 days after the end of
the cruise. The report must summarize the dates and locations of
seismic survey operations, and all marine mammal sightings (dates,
times, locations, activities, associated seismic survey activities),
and provide full documentation of methods, results, and interpretation
pertaining to all monitoring.
The draft report must also include geo-referenced time-stamped
vessel tracklines for all time periods during which airguns were
operating. Tracklines must 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). GIS files must be provided in ESRI shapefile format and include
the UTC date and time, latitude in decimal degrees, and longitude in
decimal degrees. All coordinates must be referenced to the WGS84
geographic coordinate system. In addition to the report, all raw
observational data must be made available to NMFS. The report must
summarize the data collected as described above and in the IHA. A final
report must be submitted within 30 days following resolution of any
comments on the draft report.
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 must report the
incident to the Office of Protected Resources (OPR), NMFS and to the
NMFS West Coast 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);
<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 must report the incident to OPR, NMFS and to the NMFS West Coast
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 for all active acoustic sources
operating within 50 km of the stranding. Procedures related to
shutdowns for live stranding or milling marine mammals include the
following:
<bullet> If at any time, the marine mammal(s) die or are
euthanized, or if herding/intervention efforts are stopped, the
Director of OPR, NMFS (or designee) will advise L-DEO that the shutdown
around the animals' location is no longer needed.
<bullet> 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).
<bullet> If further observations of the marine mammals indicate the
potential for re-stranding, additional coordination with L-DEO 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 responses (e.g., intensity,
[[Page 27129]]
duration), the context of any responses (e.g., critical reproductive
time or location, migration), 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's 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
environmental 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, our analysis applies to all species listed in
Table 1, given that NMFS expects the anticipated effects of the planned
geophysical survey to be similar in nature. Where there are meaningful
differences between species or stocks, or groups of species, in
anticipated individual responses to activities, impact of expected take
on the population due to differences in population status, or impacts
on habitat, NMFS has identified species-specific factors to inform the
analysis.
As described above, we have authorized only the takes estimated to
occur outside of Mexican territorial waters (Table 7); however, for the
purposes of our negligible impact analysis and determination, we
consider the total number of takes that are anticipated to occur as a
result of the entire survey (including the portion of the survey that
would occur within the Mexican territorial waters (approximately 6
percent of the survey) (Table 8).
Table 8--Total Estimated Take Including Mexican Territorial Waters
--------------------------------------------------------------------------------------------------------------------------------------------------------
Level B Level A
harassment harassment Level B Level A
(excluding (excluding harassment harassment Total Level B Total Level A
Species Mexican Mexican (Mexican (Mexican harassment harassment
territorial territorial territorial territorial
waters) waters) waters) waters)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Humpback whale.......................................... 8 0 1 0 9 0
Minke whale............................................. 2 0 0 0 2 0
Bryde's whale........................................... 27 1 2 0 29 1
Fin whale............................................... 2 0 0 0 2 0
Sei whale............................................... 3 0 0 0 3 0
Blue whale.............................................. 5 0 0 0 5 0
Sperm whale............................................. 12 0 1 0 13 0
Cuvier's beaked whale................................... 69 0 69 0 138 0
Longman's beaked whale.................................. 3 0 0 0 3 0
Mesoplodon spp.......................................... 23 0 1 0 24 0
Risso's dolphin......................................... 328 0 22 0 350 0
Rough-toothed dolphin................................... 597 0 38 0 635 0
Common bottlenose dolphin............................... 2,274 0 196 0 2,470 0
Pantropical spotted dolphin............................. 7,988 0 519 0 8,507 0
Spinner dolphin (whitebelly)............................ 121 0 7 0 128 0
Spinner dolphin (eastern)............................... 8,189 0 557 0 8,746 0
Striped dolphin......................................... 2,212 0 122 0 2,334 0
Short-beaked common dolphin............................. 2,818 0 209 0 3,027 0
Fraser's dolphin........................................ 858 0 58 0 916 0
Short-finned pilot whale................................ 244 0 15 0 259 0
Killer whale............................................ 25 0 2 0 27 0
False killer whale...................................... 118 0 8 0 126 0
Pygmy killer whale...................................... 116 0 8 0 124 0
Melon-headed whale...................................... 135 0 9 0 144 0
Kogia spp............................................... 33 1 2 0 35 1
Guadalupe fur seal...................................... 416 0 1 0 417 0
California sea lion..................................... 365 0 693 0 1,058 0
--------------------------------------------------------------------------------------------------------------------------------------------------------
NMFS does not anticipate that takes by serious injury or mortality
would occur as a result of L-DEO's planned survey, even in the absence
of mitigation, and no such takes are authorized. Non-auditory physical
effects, stranding, and vessel strike are also not expected to occur.
We have authorized a limited number of instances of Level A
harassment of two species (Bryde's whale and dwarf sperm whales, which
are members of the low- and high-frequency cetacean hearing groups,
respectively) in the form of PTS, and Level B harassment only of the
remaining marine mammal species. We believe that any PTS incurred in
marine mammals as a result of the planned activity would be in the form
of only a small degree of PTS, not total deafness, because of the
constant movement of both the R/V Langseth and of the marine mammals in
the project areas, as well as the fact that the vessel is not expected
to remain in any one area in which individual marine mammals would be
expected to concentrate for an extended period of time. Additionally,
L-DEO must 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 would be unlikely to affect the fitness of any individuals. Also, as
described above, we expect that marine mammals would likely move away
from a sound source that represents an aversive stimulus, especially at
levels that would be expected to result in PTS, given sufficient notice
of the R/V Langseth's approach due to the vessel's relatively low speed
when conducting seismic surveys. Accordingly, we expect that the
majority of takes would be in the form of short-term Level B behavioral
harassment in the form of temporary avoidance of the area or decreased
foraging (if such activity were
[[Page 27130]]
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). L-DEO will only survey ``nearshore'' tracklines
between May 1 and October 31, at which point no breeding humpback
whales are expected to be in survey area. We therefore expect no
impacts on the fitness of individual humpback whales or on recruitment
of survival for the population as a whole.
Marine mammal habitat may be impacted by elevated sound levels, but
these impacts would be temporary. Prey species are mobile and are
broadly distributed throughout the project areas; 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
relatively short duration (up to 25 days) and temporary nature of the
disturbance, 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.
Yazvenko et al. (2007) reported no apparent changes in the
frequency of feeding activity in Western gray whales exposed to airgun
sounds in their feeding grounds near Sakhalin Island. Goldbogen et al.
(2013) found blue whales feeding on highly concentrated prey in shallow
depths were less likely to respond and cease foraging than whales
feeding on deep, dispersed prey when exposed to simulated sonar
sources, suggesting that the benefits of feeding for humpbacks foraging
on high-density prey may outweigh perceived harm from the acoustic
stimulus, such as the seismic survey (Southall et al., 2016).
Additionally, L-DEO must shut down the airgun array upon observation of
an aggregation of six or more large whales, which would reduce impacts
to cooperatively foraging animals. For all habitats, no physical
impacts to habitat are anticipated from seismic activities. While SPLs
of sufficient strength have been known to cause injury to fish and fish
and invertebrate mortality, in feeding habitats, the most likely impact
to prey species from survey activities would be temporary avoidance of
the affected area and any injury or mortality of prey species would be
localized around the survey and not of a degree that would adversely
impact marine mammal foraging. The duration of fish avoidance of a
given area after survey effort stops is unknown, but a rapid return to
normal recruitment, distribution and behavior is expected. Given the
short operational seismic time near or traversing specific habitat
areas, as well as the ability of cetaceans and prey species to move
away from acoustic sources, NMFS expects that there would be, at worst,
minimal impacts to animals and habitat within these areas. The planned
survey tracklines do not overlap with any designated critical habitat
for ESA-listed species or areas of known importance for any species.
Negligible Impact Conclusions
The planned survey is of short duration (up to 25 days of seismic
operations), and the acoustic ``footprint'' of the survey is small
relative to the ranges of the marine mammals that would potentially be
affected. Sound levels would increase in the marine environment in a
relatively small area surrounding the vessel compared to the range of
the marine mammals within the survey area. Short-term exposures to
survey operations are not likely to significantly disrupt marine mammal
behavior, and the potential for longer-term avoidance of important
areas is limited.
The required 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. The required mitigation measures are also expected
to minimize the severity of any potential behavioral disturbance (Level
B harassment) via shutdowns of the airgun array. Based on previous
monitoring reports for substantially similar activities that have been
previously authorized by NMFS (available at <a href="https://www.fisheries.noaa.gov/national/marine-mammal-protection/incidental-take-authorizations-research-and-other-activities">https://www.fisheries.noaa.gov/national/marine-mammal-protection/incidental-take-authorizations-research-and-other-activities</a>), we expect that the
mitigation will be effective in preventing, at least to some extent,
potential PTS in marine mammals that may otherwise occur in the absence
of the required mitigation (although all authorized PTS has been
accounted for in this analysis).
NMFS concludes that exposures to marine mammal species and stocks
due to L-DEO's seismic survey activities would result in only short-
term (temporary and short in duration) effects to individuals exposed,
over relatively small areas of the affected animals' ranges. Animals
may temporarily avoid the immediate area, but are not expected to
permanently abandon the area. Major shifts in habitat use,
distribution, or foraging success are not expected. Due to the timing
of the survey, no impacts to breeding humpback whales are anticipated
and NMFS does not anticipate the authorized take to impact annual rates
of recruitment or survival for humpback whales or any other species.
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 the species or stock through
effects on annual rates of recruitment or survival:
<bullet> No serious injury or mortality is anticipated or
authorized, even absent mitigation;
<bullet> The planned activity is temporary and of relatively short
duration (up to 25 days);
<bullet> The anticipated impacts of the activity on marine mammals
would primarily be temporary behavioral changes due to avoidance of the
area around the survey vessel;
<bullet> The number of instances of potential PTS that may occur
are expected to be very small in number. Instances of potential PTS
that are incurred in marine mammals are expected to be of a low level,
due to constant movement of the vessel and of the marine mammals in the
area, and the nature of the survey design (not concentrated in areas of
high marine mammal concentration);
<bullet> The availability of alternate 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;
<bullet> The potential adverse effects on fish or invertebrate
species that serve as prey species for marine mammals from the survey
would be temporary and spatially limited, and impacts to marine mammal
foraging would be minimal; and
<bullet> The required mitigation measures, including visual and
acoustic monitoring and 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 required mitigation and
monitoring measures, NMFS finds that the total marine mammal take from
the planned activity will have a negligible impact on all affected
marine mammal species or stocks.
Small Numbers
As noted above, only small numbers of incidental take may be
authorized under sections 101(a)(5)(A) and (D) of the MMPA for
specified activities other
[[Page 27131]]
than military readiness activities. The MMPA does not define small
numbers and so, in practice, where estimated numbers are available,
NMFS compares the number of individuals taken to the most appropriate
estimation of abundance of the relevant species or stock in our
determination of whether an authorization is limited to small numbers
of marine mammals. When the predicted number of individuals to be taken
is fewer than one third of the species or stock abundance, the take is
considered to be of small numbers. Additionally, other qualitative
factors may be considered in the analysis, such as the temporal or
spatial scale of the activities.
The amount of authorized take is below one third of the estimated
population abundance of all species (Gerrodette and Palacios 1996; NMFS
2015b). In fact, take of individuals is less than 8 percent of the
abundance of any affected population.
Based on the analysis contained herein of the planned activity
(including the required mitigation and monitoring measures) and the
anticipated take of marine mammals, NMFS finds that small numbers of
marine mammals will be taken relative to the population size of the
affected species or stocks.
Unmitigable Adverse Impact Analysis and Determination
There are no relevant subsistence uses of the affected marine
mammal stocks or species implicated by this action. Therefore, NMFS has
determined that the total taking of affected species or stocks would
not have an unmitigable adverse impact on the availability of such
species or stocks for taking for subsistence purposes.
National Environmental Policy Act
In compliance with Executive Order (E.O.) 12114, the NSF prepared
an Environmental Analysis to consider the direct, indirect and
cumulative effects to the human environment resulting from this marine
geophysical survey in the Eastern Tropical Pacific. The NSF's
Environmental Analysis tiers to the 2011 Final Programmatic
Environmental Impact Statement/Overseas Environmental Impact Statement
for marine-related research funded by the NSF, which was prepared under
E.O. 12114 and the National Environmental Policy Act (NEPA).
NMFS determined that the form and substance of the Environmental
Analysis satisfies all the requirements of an Environmental Assessment
under NEPA, as implemented by the regulations published by the Council
on Environmental Quality (CEQ; 40 CFR parts 1500-1508) and includes
adequate information analyzing the effects on the human environment of
issuing the IHA. The NSF's draft Environmental Analysis was made
available to the public for review and comment. In compliance with NEPA
and CEQ regulations, as well as NOAA Administrative Order 216-6A, NMFS
has reviewed the NSF's Environmental Analysis, determined it to be
sufficient, and adopted that Environmental Analysis. The NSF's
Environmental Analysis and NMFS' Determination are available at <a href="https://www.fisheries.noaa.gov/national/marine-mammal-protection/incidental-take-authorizations-research-and-other-activities">https://www.fisheries.noaa.gov/national/marine-mammal-protection/incidental-take-authorizations-research-and-other-activities</a>.
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.
The NMFS OPR ESA Interagency Cooperation Division issued a
Biological Opinion under section 7 of the ESA, on the issuance of an
IHA to L-DEO under section 101(a)(5)(D) of the MMPA by the NMFS OPR
Permits and Conservation Division and the NSF's funding of L-DEO's
survey. The Biological Opinion concluded that the action is not likely
to jeopardize the continued existence of ESA-listed blue whales, fin
whales, sei whales, sperm whales, Mexico DPS humpback whales, Central
America DPS humpback whales, and Guadalupe fur seals.
Authorization
As a result of these determinations, NMFS has issued an IHA to L-
DEO for conducting geophysical surveys of the Guerrero Gap in the
Eastern Tropical Pacific in spring 2022, provided the previously
mentioned mitigation, monitoring, and reporting requirements are
incorporated.
Dated: May 2, 2022.
Kimberly Damon-Randall,
Director, Office of Protected Resources, National Marine Fisheries
Service.
[FR Doc. 2022-09792 Filed 5-5-22; 8:45 am]
BILLING CODE 3510-22-P
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</html>Indexed from Federal Register on May 6, 2022.
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