[Federal Register Volume 85, Number 21 (Friday, January 31, 2020)]
[Notices]
[Pages 5619-5633]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2020-01811]
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DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
[RTID 0648-XR069]
Takes of Marine Mammals Incidental to Specified Activities;
Taking Marine Mammals Incidental to THwaites Offshore Research (THOR)
Project in the Amundsen Sea, Antarctica
AGENCY: National Marine Fisheries Service (NMFS), National Oceanic and
Atmospheric Administration (NOAA), Commerce.
ACTION: Notice; issuance of an incidental harassment authorization.
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SUMMARY: In accordance with the regulations implementing the Marine
Mammal Protection Act (MMPA) as amended, notification is hereby given
that NMFS has issued an incidental harassment authorization (IHA) to
the National Science Foundation (NSF) Office of Polar Programs on
behalf of the University of Houston to incidentally harass, by Level B
harassment only, marine mammals during a low-energy marine geophysical
survey in the Amundsen Sea, Antarctica.
DATES: This Authorization is effective for one year from the January
24, 2020.
FOR FURTHER INFORMATION CONTACT: Bonnie DeJoseph, 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: https://www.fisheries.noaa.gov/permit/incidental-take-authorizations-under-marine-mammal-protection-act. 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 issued or, if the taking is limited to harassment, a notice of a
proposed incidental take authorization may be provided to the public
for review.
Authorization for incidental takings shall be granted if NMFS finds
that the taking will have a negligible impact on the species or
stock(s) and will not have an unmitigable adverse impact on the
availability of the species or stock(s) for taking for subsistence uses
(where relevant). Further, NMFS must prescribe the permissible methods
of taking and other ``means of effecting the least practicable adverse
impact'' on the affected species or stocks and their habitat, paying
particular attention to rookeries, mating grounds, and areas of similar
significance, and on the availability of the species or stocks for
taking for certain subsistence uses (referred to in shorthand as
``mitigation''); and requirements pertaining to the mitigation,
monitoring and reporting of the takings.
The definitions of all applicable MMPA statutory terms cited above
are included in the relevant sections below.
Summary of Request
On July 24, 2019, NMFS received a request from NSF for an IHA to
take marine mammals incidental to conducting a low-energy marine
geophysical survey and icebreaking as necessary in the Amundsen Sea.
The application was deemed adequate and complete on November 22, 2019.
NSF's request is for take of small numbers of 18 species of marine
mammals, by harassment. Neither NSF nor NMFS expects serious injury or
mortality to result from this activity and, therefore, an IHA is
appropriate. The planned activity is not expected to exceed one year.
Description of Planned Activity
NSF plans to conduct a low-energy marine seismic survey in the
Amundsen Sea during February 2020. The survey will complement Thwaites
Glacier and other Amundsen Sea oceanographic and geological/geophysical
studies and provide reference data that can be used to initiate and
evaluate the reliability of ocean models. Data obtained by the project
would assist in establishing boundary conditions seaward of the
Thwaites Glacier grounding line, obtaining records of external drivers
of change, improving knowledge of processes leading to the collapse of
Thwaites Glacier, and determining the history of past change in
grounding line migration and conditions at the glacier base.
Seismic surveys will be conducted over approximately 8400 square
kilometers (km\2\) between 75.25[deg]-73.5[deg] S and 101.0[deg]-
108.5[deg]W of the Amundsen Sea for approximately eight days beginning
on or about February 6, 2020. Sixty-five percent of data acquisition
will occur in intermediate depths (100-1000 meters (m)) and 35 percent
in deep waters (1000-< 2000 m). The surveys will involve one source
vessel, the Research Vessel/Icebreaker (RVIB) Nathaniel B. Palmer
(Palmer). NSF has stated the possibility of deploying multiple
configurations of generator injector (GI) airgun(s) with one 100-300 m,
solid-state, hydrophone streamer towed behind the Palmer. If the
preferred airgun configuration (two 45/105 cubic inch (in\3\) gun array
in true GI mode does not provide data to meet scientific objectives,
alternate configurations would be utilized (Table 1). All possible
configurations will be towed at a depth of 3 m with a total maximum
discharge volume for the largest, two-airgun array of 420 in\3\ along
predetermined track lines, approximately 1600 km. Because of the extent
of sea ice in the Amundsen Sea that typically occurs between January
and February annually, icebreaking activities are expected to be
required during the cruise.
[[Page 5620]]
Table 1--Proposed Seismic Survey Activities in the Amundsen Sea \1\
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Airgun array total volume (GI Frequency between seismic Streamer
Configuration configuration) shots length
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Preferred............................. 2 x 45/105 in\3\ (300 in\3\ 5 seconds................ 100-300 m
total). (328-984 ft)
(true GI mode)...............
Alternate 1........................... 1 x 45/105 in\3\ (150 in\3\ 5 seconds................
total) (true GI mode).
Alternate 2........................... 2 x 105/105 in\3\ (420 in\3\ 5 seconds................
(used for take request)............... total) (harmonic mode).
Alternate 3........................... 1 x 105/105 in\3\ (210 in\3\ 5 seconds................
total) (harmonic mode).
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\1\ Seismic surveying operations are planned for 1600 km (994 mi) in length.
In addition to the operations of the airgun array, a hull-mounted
Single Beam Echo Sounder (Knudsen 3260 CHIRP), Multibeam Sonar
(Kongsberg EM122), Acoustic Doppler Current Profiler (ADCP) (Teledyne
RDI VM-150 or Ocean Surveyor OS-38), as well as EK biological echo
sounder (Simrad ES200-7C, ES38B, ES-120-7C) will also be operated from
the Palmer during the cruise.
A detailed description of the planned THOR project was provided in
the Federal Register notice for the proposed IHA published on December
19, 2019 (84 FR 69950). 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.
Mitigation, monitoring, and reporting measures are described in
detail later in this document (please see Mitigation and Monitoring and
Reporting).
BILLING CODE 3510-22-P
[[Page 5621]]
[GRAPHIC] [TIFF OMITTED] TN31JA20.012
BILLING CODE 3510-22-C
Comments and Responses
A notice of NMFS's proposal to issue an IHA to NSF was published in
the Federal Register on December 19, 2019 (84 FR 69950). That notice
described, in detail, NSF'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 a
comment letter from the Marine Mammal Commission (Commission). For full
detail of the Commission's recommendations and supporting rationale,
please see the letter (available online at: www.fisheries.noaa.gov/action/incidental-take-authorization-thwaites-offshore-research-thor-project-amundsen-sea-antartica).
Comment: The Commission recommends that NMFS: (1) Specify whether
NSF's activities would occur in international waters, the deepest water
[[Page 5622]]
depth in which the geophysical survey would occur, and the parameters
and methods used to estimate the Level B harassment zone for ice-
breaking activities; (2) use the humpback whale density of 0.001365
whales/km\2\ based on Gohl (2010) to re-estimate the numbers of takes
for the geophysical survey and ice-breaking activities; (3)(a) revise
the (i) Level A and B harassment zones for the geophysical survey based
on a tow depth of 4 m rather than 3 m or restrict the airguns from
being towed at a depth of more than 3 m and (ii) ensonified areas for
Level B harassment based on transiting 200 km rather than 160 km per
day during the geophysical survey and (b) use the total ensonified area
for Level B harassment to re-estimate the numbers of takes for the
geophysical survey; and (4) increase the numbers of Level B harassment
takes to at least 3 blue whales, 40 humpback whales, 40 killer whales,
2,000 crabeater seals, 100 Weddell seals, 50 leopard seals, and 10 Ross
seals based on group size and documented occurrence in the Amundsen
Sea.
Response: NSF has confirmed that the survey will occur entirely
within international waters, and that the maximum survey depth is 1,900
m. The parameters and methods used to estimate the Level B harassment
zone for ice-breaking activities are described in the ``Estimated
Take'' section later in this document. Regarding humpback whale
density, NMFS concurs with the Commission and has produced revised
exposure estimates using the recommended density value (see ``Estimated
Take,'' later in this document). NSF intends to tow the acoustic source
at a depth of 3 m; therefore, this value was used in modeling of the
acoustic harassment isopleths. NMFS also concurs with the Commission
regarding the daily transit distance of 200 km and has revised the
exposure estimates accordingly. Similarly, exposure estimate
calculations have been performed using the total ensonified area, as
recommended by the Commission.
Regarding the recommendation to increase certain authorized take
numbers on the basis of expected group size encounters, NMFS concurs
with the Commission and has made the recommended adjustments, with two
exceptions. NMFS disagrees with the Commission regarding the likelihood
of encountering a group of three blue whales, and has retained the
initial estimate of two. Blue whales, a rarely encountered species, are
typically encountered as single animals or as small groups of up to 2
or 3 animals. Therefore, the estimate of two blue whale takes is
sufficient to account for likely group size. For killer whales, we
revisited the available information and derived a more appropriate
density value on the basis of available observational data (as
described below under ``Changes from the Proposed IHA to Final IHA'').
The revised exposure estimate exceeds the Commission's recommended
group size estimate.
Comment: Regarding ice-breaking, the Commission recommends that
NMFS use the total ensonified area of 8,491 km\2\ to estimate the
numbers of Level B harassment takes if ice-breaking activities could
occur on any of the survey days, or use the reduced ensonified area of
7,409 km\2\ to estimate the numbers of Level B harassment takes if ice-
breaking activities are expected to occur for two straight days.
Response: The maximum estimated amount of icebreaking expected by
NSF, i.e., 445 km for the maximum of 48 hours, was used in our
calculations to avoid the significant overestimation that would result
from assuming icebreaking will occur every day (10 survey days,
including 2 contingency days). It is unlikely that any given animal
would experience the stressor continuously for 10 days, and the
potential effects of ice-breaking have been appropriately accounted for
in NMFS' authorized take levels.
Comment: The Commission recommends that NMFS (1) include a
requirement to extrapolate Level B harassment takes to the unobserved
portions of the Level B harassment zone and (2) ensure that NSF keeps a
running tally of total Level B harassment takes based on both observed
and extrapolated takes.
Response: NMFS agrees that NSF must ensure they do not exceed
authorized takes. As is typical in such authorizations, we have
included a requirement that NSF report ``estimates of the number and
nature of exposures that occurred above the harassment threshold based
on PSO observations, including an estimate of those that were not
detected.''
Comment: The Commission recommends that NMFS require NSF to either
(1) re-estimate the proposed Level A and B harassment zones and
associated takes of marine mammals using (a) both operational and site-
specific environmental parameters, (b) a comprehensive source model and
(c) an appropriate sound propagation model for the proposed incidental
harassment authorization; or (2) collect or provide the relevant
acoustic data to substantiate that its modeling approach is
conservative for both deep and intermediate waters beyond the Gulf of
Mexico. The Commission further recommends that NMFS (1) explain why it
believes that sound channels with downward refraction, as well as
seafloor reflections, are not likely to occur during the geophysical
survey; (2) specify the degree to which both of those parameters would
affect the estimation (or underestimation) of Level B harassment zones
in deep and intermediate water; (3) explain why it believes that NSF's
model and other `modeling' approaches provide more accurate, realistic,
and appropriate Level A and B harassment zones than approaches favored
by the Commission, particularly for deep and intermediate water; and
(4) explain, if NSF's model and other `modeling' approaches are
considered best available science, why other action proponents that
conduct seismic surveys are not implementing similar methods
particularly given their simplicity.
Response: As noted by the Commission, these comments reflect a
longstanding disagreement between NMFS and the Commission regarding
NSF's approach to modeling the output of their acoustic sources and its
propagation through the water column. NMFS has previously responded to
the Commission's comments on NSF's modeling approach. We refer the
reader to previous Federal Register notices providing responses rather
than repeat them here (e.g., 84 FR 60059, November 07, 2019; 84 FR
54849, October 11, 2019; 84 FR 35073, July 22, 2019). However, given
the Commission's continuing concerns with NSF's modeling approach for
its broader survey program (and not solely for the subject survey),
NMFS also will engage separately with the Commission about these
issues.
Comment: The Commission recommends that NMFS post on its website
the same day a notice of proposed authorization publishes in the
Federal Register the application, the draft incidental harassment
authorization, any hydroacoustic or marine mammal monitoring plans, its
list of references, previous monitoring reports, and any other related
documents.
Response: NMFS concurs with the recommendation.
Comment: The Commission reiterates programmatic recommendations
regarding NMFS' potential use of the renewal mechanism for one-year
IHAs.
Response: NMFS disagrees with the Commission's recommendations, as
stated in our previous comment responses relating to other actions,
which we incorporate here by reference (e.g., 84 FR 52464; October 02,
2019).
[[Page 5623]]
Changes From the Proposed IHA to Final IHA
Corrections have been made to the estimated take table (see Table
9), as well as population (see Table 2) values updated and density (see
Table 7) values corrected for two and three species, respectively. More
recent sources were found for the population abundance of crabeater and
Weddell seals. Bengston et al. (2011) reported 2,100,000 crabeater
seals in the Ross and Amundsen Sea, which is more relevant to NSF's
survey in the Amundsen Sea than Boyd's (2002) report of 5,000,000 seals
in the entire Antarctic. For Weddell seals, H[uuml]ckst[auml]dt updated
their population estimate from 750,000 (2015) to 1,000,000 (2018)
seals.
We re-evaluated the density values and found that the Protected
Species Observer Report from a previous NSF Antarctic cruise (Mehle et
al. 2015) had higher monitoring/observation counts for minke and killer
whales. Thus, the higher Mehle et al. (2015) counts were used for a
more conservative take estimate than those used in the proposed IHA;
i.e., Ainley et al. (2007) for minke whales and NMSDD (2012) for killer
whales. Since both the Ainley et al. (2007) and Mehle et al. (2015)
monitoring efforts were conducted from the same vessel, the Palmer, in
Antarctica, NMFS used the same calculation method as NSF with the
Ainley et al. (2007) data. Therefore, the 1.6 km visual transect width
and 556 km survey distance were used to produce the area surveyed,
889.6 km\2\, which allowed the calculation of the density area.
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 about these species (e.g., physical and
behavioral descriptions) may be found on NMFS's website (https://www.fisheries.noaa.gov/find-species).
The populations of marine mammals considered in this document do
not occur within the U.S. Exclusive Economic Zone (EEZ) and are
therefore not assigned to stocks and are not assessed in NMFS' Stock
Assessment Reports (SAR). As such, information on potential biological
removal (PBR; defined by the MMPA as the maximum number of animals, not
including natural mortalities, that may be removed from a marine mammal
stock while allowing that stock to reach or maintain its optimum
sustainable population) and on annual levels of serious injury and
mortality from anthropogenic sources are not available for these marine
mammal populations. Abundance estimates for marine mammals in the
survey location are based on a variety of sources including
International Whaling Commission population estimates (IWC 2019), The
International Union for Conservation of Nature's (IUCN) Red List of
Threatened Species, and various literature estimates (see IHA
application for further detail), as this is considered the best
available information on potential abundance of marine mammals in the
area.
Table 2 lists all species with expected potential for occurrence in
the Amundsen Sea, Antarctica, and summarizes information related to the
population, including regulatory status under the MMPA and ESA. For
taxonomy, we follow the Committee on Taxonomy (2019).
Table 2--Marine Mammal Species Potentially Present in the Project Area Expected To Be Affected by the Specified Activities
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ESA/MMPA status; Stock
Common name Scientific name Stock \1\ Strategic (Y/N) \2\ abundance PBR
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Order Cetartiodactyla--Cetacea--Superfamily Mysticeti (baleen whales)
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Family Balaenopteridae (rorquals)
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Blue whale........................ Balaenoptera musculus.... N/A E/D;Y \3\ 5,000 N/A
Fin whale......................... Balaenoptera physalus.... N/A E/D;Y \4\ 38,200 N/A
Humpback whale.................... Megaptera novaeangliae... N/A - \5\ 42,000 N/A
Common (dwarf) minke whale........ Balaenoptera N/A - \6\ 257,500 N/A
acutorostrata.
Antarctic minke whale............. Balaenoptera bonaerensis. N/A - \6\ 257,500 N/A
Sei whale......................... Balaenoptera borealis.... N/A E \7\ 10,000 N/A
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Superfamily Odontoceti (toothed whales, dolphins, and porpoises)
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Family Physeteridae
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Sperm whale....................... Physeter macrocephalus... N/A E \8\ 12,069 N/A
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Family Ziphiidae (beaked whales)
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Arnoux's beaked whale............. Berardius arnuxii........ N/A - \9\ 599,300 N/A
Gray's beaked whale............... Mesoplodon grayi......... N/A - \9\ 599,300 N/A
Layard's beaked whales............ Mesoplodon layardii...... N/A ....................... \9\ 599,300 N/A
Southern bottlenose............... Hyperoodon planifrons.... N/A - \10\ 500,000 N/A
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Family Delphinidae
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Killer whale...................... Orcinus orca............. N/A - \11\ 25,000 N/A
Long-finned whale................. Globicephala N/A - \12\ 200,000 N/A
macrorhynchus.
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Family Phocidae (earless seals)
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Crabeater seal.................... Lobodon carcinophaga..... N/A - \13\ 2,100,000 N/A
Leopard seal...................... Hydrurga leptonyx........ N/A - \14\ 222,000 N/A
[[Page 5624]]
Southern elephant seal............ Mirounga leonina......... N/A - \15\ 750,000 N/A
Ross seal......................... Ommatophoca rossii....... N/A - \16\ 250,000 N/A'
Weddell seal...................... Leptonychotes weddellii.. N/A - \17\ 1,000,000 N/A
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N.A. = data not available.
\1\ The populations of marine mammals considered in this document do not occur within the U.S. EEZ and are therefore not assigned to stocks.
\2\ 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.
\3\ Antarctic Range 5-8,000 (Cooke 2018).
\4\ Aguilar & Garc[iacute]a-Vernet 2018.
\5\ Partial coverage of Antarctic feeding grounds (IWC 2019).
\6\ Split of undifferentiated minke whale population abundance, total of 515,000 in the Southern Hemisphere (IWC 2019).
\7\ Cooke 2018.
\8\ Estimate for the Antarctic, south of 60[deg] S (Whitehead 2002).
\9\ All beaked whales south of the Antarctic Convergence; mostly southern bottlenose whales (Kasamatsu & Joyce 1995).
\10\ Jefferson et al. 2008.
\11\ Branch & Butterworth 2001.
\12\ Antarctic (Boyd 2002).
\13\ Ross and Amundsen Sea (Bengston et al., 2011).
\14\ Global population is 222,000-440,000 (Rogers 2018).
\15\ Total world population (Hindell et al., 2016)
\16\ H[uuml]ckst[auml]dt 2015.
\17\ H[uuml]ckst[auml]dt 2018.
All species that could potentially occur in the planned survey
areas are included in Table 2. As described below, all 18 species
temporally and spatially co-occur with the activity to the degree that
take is reasonably likely to occur, and we have authorized it.
A detailed description of the of the species likely to be affected
by the THOR geophysical survey, including brief introductions to the
species and relevant stocks as well as available information regarding
population trends and threats, information regarding local occurrence,
and marine mammal hearing were provided in the Federal Register notice
for the proposed IHA (84 FR 69950; December 19, 2019). Since that time,
we are not aware of any changes in the status of these species and
stocks; therefore, detailed descriptions are not provided here. Please
refer to that Federal Register notice for these descriptions.
Potential Effects of Specified Activities on Marine Mammals and Their
Habitat
The effects of underwater noise from NSF's planned geophysical
survey have the potential to result in harassment of marine mammals in
the vicinity of the survey area. The Federal Register notice for the
proposed IHA (84 FR 69950; December 19, 2019) included a discussion of
the effects of anthropogenic noise 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 that
Federal Register notice (84 FR 69950; December 19, 2019) for that
information. No instances of Level A harassment, serious injury or
mortality are expected as a result of the planned activities.
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 will be by Level B harassment only, in the form of
disruption of behavioral patterns for individual marine mammals
resulting from exposure to the acoustic stressors. Based on the nature
of the acoustic sources planned for this activity (i.e., small Level A
harassment zones), Level A harassment is neither anticipated, nor
authorized. In addition, the anticipated effectiveness of the
mitigation measures (i.e., visual mitigation monitoring; establishment
of an exclusion zone; shutdown procedures; ramp-up procedures; and
vessel strike avoidance measures), discussed in detail below in the
Mitigation section, further reduce the likelihood that Level A
harassment may occur.
As described previously, no 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 harassed or incur some degree of
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) and 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 authorized take
estimate.
[[Page 5625]]
Acoustic Thresholds
Using the best available science, NMFS has developed 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 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 [mu]Pa (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.
NSF's planned activity includes the use of impulsive seismic
sources and continuous icebreaking, and therefore both 160 dB re 1
[mu]Pa (rms) and 120 dB re 1 [mu]Pa (rms) are applicable for the
related activity, respectively.
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). NSF's planned activity includes impulsive
and non-impulsive acoustic 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
https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-acoustic-technical-guidance.
Table 3--Thresholds Identifying the Onset of Permanent Threshold Shift
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PTS onset acoustic thresholds \*\ (received level)
Hearing group ------------------------------------------------------------------------
Impulsive Non-impulsive
----------------------------------------------------------------------------------------------------------------
Low-Frequency (LF) Cetaceans........... Cell 1: Lpk,flat: 219 dB; Cell 2: LE,LF,24h: 199 dB.
LE,LF,24h: 183 dB.
Mid-Frequency (MF) Cetaceans........... Cell 3: Lpk,flat: 230 dB; Cell 4: LE,MF,24h: 198 dB.
LE,MF,24h: 185 dB..
High-Frequency (HF) Cetaceans.......... Cell 5: Lpk,flat: 202 dB; Cell 6: LE,HF,24h: 173 dB.
LE,HF,24h: 155 dB..
Phocid Pinnipeds (PW) (Underwater)..... Cell 7: Lpk,flat: 218 dB; Cell 8: LE,PW,24h: 201 dB.
LE,PW,24h: 185 dB..
Otariid Pinnipeds (OW) (Underwater).... Cell 9: Lpk,flat: 232 dB; Cell 10: LE,OW,24h: 219 dB.
LE,OW,24h: 203 dB..
----------------------------------------------------------------------------------------------------------------
* Dual metric acoustic thresholds for impulsive sounds: Use whichever results in the largest isopleth for
calculating PTS onset. If a non-impulsive sound has the potential of exceeding the peak sound pressure level
thresholds associated with impulsive sounds, these thresholds should also be considered.
Note: Peak sound pressure (Lpk) has a reference value of 1 [micro]Pa, and cumulative sound exposure level (LE)
has a reference value of 1[micro]Pa\2\s. In this Table, thresholds are abbreviated to reflect American
National Standards Institute standards (ANSI 2013). However, peak sound pressure is defined by ANSI as
incorporating frequency weighting, which is not the intent for this Technical Guidance. Hence, the subscript
``flat'' is being included to indicate peak sound pressure should be flat weighted or unweighted within the
generalized hearing range. The subscript associated with cumulative sound exposure level thresholds indicates
the designated marine mammal auditory weighting function (LF, MF, and HF cetaceans, and PW and OW pinnipeds)
and that the recommended accumulation period is 24 hours. The cumulative sound exposure level thresholds could
be exceeded in a multitude of ways (i.e., varying exposure levels and durations, duty cycle). When possible,
it is valuable for action proponents to indicate the conditions under which these acoustic thresholds will be
exceeded.
Ensonified Area
Here, we describe operational and environmental parameters of the
activity that will feed into identifying the area ensonified above the
acoustic thresholds, which include source levels and transmission loss
coefficient.
When the NMFS Technical Guidance (2016) was published, in
recognition of the fact that ensonified area/volume could be more
technically challenging to predict because of the duration component in
the new thresholds, we developed a User Spreadsheet that includes tools
to help predict a simple isopleth that can be used in conjunction with
marine mammal density or occurrence to help predict takes. We note that
because of some of the assumptions included in the methods used for
these tools, we anticipate that isopleths produced are typically going
to be overestimates of some degree, which may result in some degree of
overestimate of potential take by Level A harassment. However, these
tools offer the best way to predict appropriate isopleths when more
sophisticated modeling methods are not available. NMFS continues to
develop ways to quantitatively refine these tools, and will
qualitatively address the output where appropriate. For mobile sources
such as seismic surveys and icebreaking, 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. Inputs used in the User Spreadsheet, and the resulting
isopleths, are reported below in Tables 4, 5, and 6. As noted in Table
1, the two 45/105 in\3\ GI guns is the preferred configuration for
NSF's survey. However, values from the GI configuration Alternate 2,
two 105/105 in\3\ (420 in\3\ total), have been used as the basis for
modeling and all related take calculations due to its larger volume
(and greater acoustic output) to present the most conservative modeling
effort.
Table 4--SELcum Methodology
------------------------------------------------------------------------
------------------------------------------------------------------------
Source Velocity (meters/second)......................... * 2.315
1/Repetition rate [caret] (seconds)..................... ** 5
------------------------------------------------------------------------
Note: Methodology assumes propagation of 20 log R; Activity duration
(time) independent.
[caret] Time between onset of successive pulses.
* 4.5 kts.
** shot interval assumed to be 5 seconds.
Table 5 presents the estimated Level A harassment zones for each
marine mammal hearing group, which are based on L-DEO modeling
incorporated into the companion User Spreadsheet (NMFS 2018).
[[Page 5626]]
Table 5--Predicted Distances to the Level A Threshold for Marine Mammals
----------------------------------------------------------------------------------------------------------------
SEL cumulative SEL cumulative Peak PTS Peak PTS \2\
Hearing group PTS threshold PTS distance threshold distance (m)
(dB) \1\ (m) \1\ (dB) \1\ \1\
----------------------------------------------------------------------------------------------------------------
Low-frequency cetaceans......................... 183 31.1 219 7.55
Mid-frequency cetaceans......................... 185 0.0 230 1.58
Phocid pinnipeds................................ 185 0.3 218 8.47
----------------------------------------------------------------------------------------------------------------
\1\ Cumulative sound exposure level for PTS (SELcumPTS) or Peak (SPLflat) resulting in Level A harassment (i.e.,
injury). Based on 2018 NMFS Acoustic Technical Guidance (NMFS 2018).
\2\ Per NMFS Acoustic Technical Guidance (NMFS 2018), the larger of the dual criteria results are used for the
EZ; GI configuration Alternate 2, 2 x 105/105 in\3\ (420 in\3\ total).
Predicted distances to Level A harassment isopleths, which vary
based on marine mammal hearing groups, were calculated based on
modeling performed by L-DEO using the NUCLEUS software program and the
NMFS User Spreadsheet 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 predicted distances for Level A harassment are sufficiently
small (see Table 5), that the likelihood of Level A harassment for any
marine mammal is considered discountable. Given these small zones and
the likelihood that any animal would demonstrate aversive behavior to
the presence of the vessel at such close ranges, it is unrealistic that
a mammal would stay within such a small area long enough to incur onset
of PTS. Hence, Level A harassment is not expected or authorized for
this survey.
L-DEO's modeling methodology is explained in greater detail in the
proposed IHA notice (84 FR 69950; December 19, 2019). Please refer to
NSF's IHA application, Attachment A for the Model Report Estimating the
Mitigation Zones for Airgun Arrays that could be used in the Amundsen
Sea, NSF survey. The estimated distances to the Level B harassment
isopleths for all proposed airgun configurations in each water depth
category are shown in Table 6.
Table 6--Level B--Predicted Distances to the Level B Threshold
(160 re 1[micro]Parms isopleths)
----------------------------------------------------------------------------------------------------------------
Predicted 160 re
Source and volume (cm\3\)[in\3\] Tow depth (m) Water depth 1[micro]Parms (m)
(m) \1\ isopleth \2\
----------------------------------------------------------------------------------------------------------------
2 x 45/105 in\3\ (300 in\3\) GI guns \*\..................... 3 100-1000 979
.............. >1000 653
1 x 45/105 in\3\ (150 in\3\) GI guns ***..................... 3 100-1000 503
.............. >1000 335
2 x 105/105 in\3\ (420 in\3\) GI guns **..................... 3 100-1000 1044
.............. >1000 696
1 x 105/105 in\3\ (210 in\3\) GI guns ***.................... 3 100-1000 531
.............. >1000 354
----------------------------------------------------------------------------------------------------------------
\1\ No seismic operations would be conducted in shallow depths (0-100 m).
\2\ RMS radii is based on LDEO modeling and empirical measurements. Radii for 100-1000 m depth values = deep
water values * 1.5 correction factor.
* Preferred configuration.
** Configuration used in all related take calculations to present the maximum possible effect of the survey.
*** Alternates.
Marine Mammal Occurrence
In this section we provide the information about the presence,
density, or group dynamics of marine mammals that informed the take
calculations.
For the planned survey area in west Antarctica, NSF and NMFS
determined that the preferred sources of density data for marine mammal
species that might be encountered in the project area were Ainley et
al. (2007), Gohl (2010), and Navy Marine Species Density Database
(2012). Densities were estimated using sightings and effort during
aerial and vessel-based surveys conducted in and adjacent to the
proposed project area, as well as from cetacean density models (NMSDD
2012; see NSF IHA application). NMFS finds the available monitoring
information from the previous NSF cruise in the Ross Sea (Mehle et al.
2015), based on their observations of 14 sightings of 254 killer whales
and 2 blue whales, to support group size and be the most conservative.
In addition, NMFS included the southern elephant seal to the marine
mammals potentially present in the project area (Hofmeyr 2015), and
divided the available minke whale data, which is undifferentiated, into
the two species that may be affected; Antarctic and Common (dwarf)
minke whales.
Since Mehle et al. (2015) reported monitoring information rather
than specific densities, and both the Ainley et al. (2007) and Mehle et
al. (2015) monitoring efforts were conducted from the same vessel, the
Palmer, in Antarctica, NMFS derived density values from Mehle et al.
(2015) using the same calculation method as was used by NSF to
calculate density from the Ainley et al. (2007) data. Specifically, we
used the 1.6 km visual transect width and 556 km survey distance to
produce 889.6 km \2\ area surveyed, allowing the number of individuals
sighted to be divided by the area to obtain a density value for each
relevant species.
All data sources used for animal abundance are listed in Table 2
above. Estimated densities used to inform take estimates are presented
in Table 7.
[[Page 5627]]
Table 7--Marine Mammal Densities in the Proposed Survey Area
------------------------------------------------------------------------
Areal density
Species (#/km2) Data source
------------------------------------------------------------------------
Low-frequency cetaceans
------------------------------------------------------------------------
Blue whale........................ 0.00005 NMSDD 2012
Fin whale......................... 0.00722 NMSDD 2012.
Humpback whale.................... 0.00014 Gohl 2010.
Minke whale....................... 1.14996 Mehle et al. 2015.
Antarctic minke whale............. 0.57498 ....................
Common (dwarf) minke whale........ 0.57498 ....................
Sei whale......................... 0.00026 NMSDD 2012.
------------------------------------------------------------------------
Mid-frequency cetaceans
------------------------------------------------------------------------
Arnoux's beaked whale............. 0.00624 NMSDD 2012.
Killer whale...................... 0.28552 NMSDD 2012.
Layard's beaked whale............. 0.00064 Mehle et al. 2015.
Long-finned pilot whale........... 0.00786 NMSDD 2012.
Southern bottlenose whale......... 0.00676 NMSDD 2012.
Sperm whale....................... 0.01699 NMSDD 2012.
Gray's beaked whale............... 0.00028 Ainley et al., 2007.
------------------------------------------------------------------------
Phocids
------------------------------------------------------------------------
Crabeater seal.................... 0.00762 Gohl 2010.
Leopard seal...................... 0.00005 Gohl 2010.
Ross seal......................... 0.00001 Gohl 2010.
Southern Elephant Seal............ 1.03175 Hindell et al.,
2016.
Weddell seal...................... 0.00013 Gohl 2010.
------------------------------------------------------------------------
Notes:
- Where the area surveyed was not indicated in the reference document, a
value of 315,000 km\2\ was used, estimate of the area of the Amundsen
Sea Continental shelf (Jacobs 2012).
- NMSDD-Maximum density values during the austral summer for the
Amundsen Sea (between 100[deg]W-105[deg]W and south of 70[deg]S).
Take Calculation and Estimation
Here we describe how the information provided above is brought
together to produce a quantitative take estimate.
Seismic Surveys
In order to estimate the number of marine mammals predicted to be
exposed to sound levels that would result in Level B harassment, radial
distances from the airgun array to predicted isopleths corresponding to
the Level B harassment thresholds are calculated, as described in the
notice of proposed IHA. 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 B harassment
thresholds. The area estimated to be ensonified in a single day of the
survey is then calculated (Table 8), based on the areas predicted to be
ensonified around the array and the estimated trackline distance
traveled per day. This number is then multiplied by the number of
survey days. The product is then multiplied by 1.25 to account for the
additional 25 percent contingency. This results in an estimate of the
total area (km \2\) expected to be ensonified to the Level B harassment
thresholds for each acoustic source (Table 8).
Table 8--Areas (km \2\) To Be Ensonified to Level B Harassment Thresholds
----------------------------------------------------------------------------------------------------------------
Daily
Distance/day ensonified Number days of Plus 25% Total
Criteria (km) area w/endcaps survey buffer (days) ensonified
(km 2) area
----------------------------------------------------------------------------------------------------------------
LEVEL B Area (160 dB)
----------------------------------------------------------------------------------------------------------------
65% = 100-1000 m................ 130 274.86 8.00 10.00 2,748.62
35% = >1000 m................... 70 98.96 8.00 10.00 989.61
-------------------------------------------------------------------------------
ALL DEPTHS...................... .............. .............. .............. .............. 3,738.23
----------------------------------------------------------------------------------------------------------------
Icebreaking (120 dB)
----------------------------------------------------------------------------------------------------------------
223 3003.8 2.00 2.50 7509.49
----------------------------------------------------------------------------------------------------------------
The marine mammals predicted to occur within these respective
areas, based on estimated densities (Table 7), are assumed to be
incidentally taken. As discussed previously, based on the small
anticipated Level A harassment isopleths and in consideration of the
mitigation measures (see Mitigation section below), take by Level A
[[Page 5628]]
harassment is not expected to occur and is not authorized. Estimated
exposures for the planned survey are shown in Table 9.
Icebreaking
The USCGC Healy served as a proxy for the source levels expected to
result from icebreaking by the Palmer to calculate the ensonified area
(Table 8) and Level B take (Table 9): 196.2 db at 1 m source level
(Roth 2013), transmission loss 20logR, assuming spherical spreading,
and resulting 6.456 km radius to the 120 dB harassment threshold. The
maximum estimated amount of icebreaking expected by NSF; i.e. 445 km
for the maximum of 48 hours, was used in these calculations to avoid
the significant overestimation of assuming icebreaking will occur every
day (8 survey days, plus 2 contingency days). We calculate the
ensonified area associated with icebreaking using the maximum duration
of 48 hours icebreaking rather than the 10 days of the potential
survey, as it is unlikely that any given animal would experience the
stressor continuously for 10 days.
It should be noted that the authorized take numbers shown in Table
9 are expected to be conservative because in the calculations of
estimated take, 25 percent has been added in the form of operational
survey days. This is to account for the possibility of additional
seismic operations associated with airgun testing and repeat coverage
of any areas where initial data quality is sub-standard.
Following our development of the aforementioned take estimates, and
based on our review of recommendations from the Marine Mammal
Commission (described previously in ``Comments and Responses'') we
increased Level B harassment take estimates for the following species
as stated here: 40 humpback whales, 2,000 crabeater seals, 100 Weddell
seals, 50 leopard seals, and 10 Ross seals based on group size and
documented occurrence in the Amundsen Sea (Gohl 2010).
Table 9--Calculated and Authorized Level B Exposures, and Percentage of Stock Exposed
----------------------------------------------------------------------------------------------------------------
Calculated Calculated
Species level B take level B take Authorized Percent of
seismic icebreaking total take population
----------------------------------------------------------------------------------------------------------------
Low-frequency cetaceans
----------------------------------------------------------------------------------------------------------------
Blue whale...................................... 1 1 2 0
Fin whale....................................... 27 54 81 0.2
Humpback whale.................................. 1 1 40 \b\ 0.1
Antarctic minke whale........................... 2,149 4,318 6,467 2.5
Common (dwarf) minke whale...................... 2,149 4,318 6,467 2.5
Sei whale....................................... 1 2 6 \a\ 0
----------------------------------------------------------------------------------------------------------------
Mid-frequency cetaceans
----------------------------------------------------------------------------------------------------------------
Arnoux's beaked whale........................... 23 47 70 0
Killer whale.................................... 1,067 2,144 3,211 12.8
Layard's beaked whale........................... 2 5 7 0
Long-finned pilot whale......................... 29 59 88 0
Southern bottlenose whale....................... 25 51 76 0
Sperm whale..................................... 63 128 191 1.6
Gray's beaked whale............................. 1 2 3 0
----------------------------------------------------------------------------------------------------------------
Phocids
----------------------------------------------------------------------------------------------------------------
Crabeater seal.................................. 28 57 2,000 \c\ 0.1
Leopard seal.................................... 0 0 50 \c\ 0
Ross seal....................................... 0 0 10 \c\ 0
Southern elephant Seal.......................... 8,897 7,748 16,645 6.7
Weddell seal.................................... 0 1 100 \c\ 0
----------------------------------------------------------------------------------------------------------------
a. Authorized take increased to group size from W[uuml]rsig et al. (2018).
b. Changed based on recommendation from the MMC based on a group of four whales being taken on each of the 10
days. Gohl (2010) did not specify the group size of humpback whales observed in the Amundsen Sea, but Thiele
et al. (2004) documented group size of up to four humpback whales in a given group off the western Antarctic
Peninsula.
c. Changed based on recommendation from the MMC, the numbers of pinniped takes were based on the relative
occurrence of the various species based on Gohl (2010). 200 crabeater seals, 10 Weddell seals, 5 leopard
seals, and 1 Ross seal could be taken on each of the 10 days of activities.
Mitigation Measures
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
[[Page 5629]]
the nature of the potential adverse impact being mitigated (likelihood,
scope, range). It further considers the likelihood that the measure
will be effective if implemented (probability of accomplishing the
mitigating result 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.
Mitigation for Marine Mammals and Their Habitat
NSF has reviewed mitigation measures employed during seismic
research surveys authorized by NMFS under previous incidental
harassment authorizations, as well as recommended best practices in
Richardson et al. (1995), Pierson et al. (1998), Weir and Dolman
(2007), Nowacek et al. (2013), Wright (2014), and Wright and Cosentino
(2015), and has incorporated a suite of required mitigation measures
into their project description based on the above sources.
To reduce the potential for disturbance from acoustic stimuli
associated with the activities, NSF is required to implement mitigation
measures for marine mammals. Mitigation measures that must be adopted
during the planned surveys include (1) Vessel-based visual mitigation
monitoring; (2) Establishment of a marine mammal Exclusion Zone (EZ)
and buffer zone; (3) shutdown procedures; (4) ramp-up procedures; and
(4) vessel strike avoidance measures.
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 visually for the presence of marine mammals. PSO(s) 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). Following a shutdown for any reason,
observations must occur for at least 30 minutes prior to the planned
start of airgun operations. Observations must also occur for 60 minutes
after airgun operations cease for any reason (or until 30 minutes
following sunset). Observations must also be made during daytime
periods when the Palmer is underway without seismic operations, such as
during transits, to allow for comparison of sighting rates and behavior
with and without airgun operations and between acquisition periods.
Airgun operations must be suspended when marine mammals are observed
within, or about to enter, the designated EZ (as described below).
During seismic operations, three visual PSOs must be based aboard
the Palmer. PSOs must be appointed by NSF with NMFS approval. One
dedicated PSO must monitor the EZ during all daytime seismic
operations. PSO(s) must be on duty in shifts of duration no longer than
four hours. Other vessel crew must also be instructed to assist in
detecting marine mammals and in implementing mitigation requirements
(if practical). Before the start of the seismic survey, the crew must
be given additional instruction in detecting marine mammals and
implementing mitigation requirements.
The Palmer is a suitable platform from which PSOs will watch for
marine mammals. Standard equipment for marine mammal observers must be
7 x 50 reticule binoculars and optical range finders. At night, night-
vision equipment must be available. The observers must be in
communication with ship's officers on the bridge and scientists in the
vessel's operations laboratory, so they can advise promptly of the need
for avoidance maneuvers or seismic source shutdown.
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 must be provided to NMFS for
approval. At least one PSO must have a minimum of 90 days at-sea
experience working as a PSO during a seismic survey. One
``experienced'' visual PSO must be designated as the lead for the
entire protected species observation team. The lead will serve as
primary point of contact for the vessel operator.
Exclusion Zone and Buffer Zone
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, severe behavioral reaction. The PSOs
must establish a minimum EZ with a 100 m radius for the airgun array.
The EZs must be based on radial distance from any element 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 (see Shutdown Procedures below).
The 100-m radial distance of the standard EZ is precautionary in
the sense that it is expected to contain sound exceeding injury
criteria for all marine mammal hearing groups (Table 3) while also
providing a consistent, reasonably observable zone within which PSOs
will typically be able to conduct effective observational effort. In
this case, the 100-m radial distance is also expected to contain sound
that will exceed the Level A harassment threshold based on sound
exposure level (SELcum) criteria for all marine mammal
hearing groups (Table 3).
Our intent in prescribing a standard EZ distance is to (1)
encompass zones within which auditory injury could occur on the basis
of instantaneous exposure; (2) provide additional protection from the
potential for more severe behavioral reactions (e.g., panic,
antipredator response) for marine mammals at relatively close range to
the acoustic source; (3) provide consistency for PSOs, who need to
monitor and implement the EZ; and (4) define a distance within which
detection probabilities are reasonably high for most species under
typical conditions.
PSOs will also establish and monitor an additional buffer to the
exclusion zone, i.e., must monitor the 100-m exclusion zone plus an
additional 100-m buffer for a total of 200 m. During use of the
acoustic source, occurrence of marine mammals within the buffer zone
(but outside the EZ) will be communicated to the operator to prepare
for potential shutdown of the acoustic source. In context of the larger
extended EZ (discussed in the following paragraph), the buffer zone is
largely applicable to the pre-clearance period prior to beginning the
ramp-up procedure (as discussed further under Ramp-up Procedures, later
in this section).
An extended EZ of 500 m must be enforced for all beaked whales and
for Southern right whales. The latter is a precautionary measure as
right whales are not expected in the survey area. NSF will also
implement a 500-m EZ for aggregations of six or more large whales
(i.e., sperm whale or any baleen whale) or a large whale with a calf
(calf defined as an animal less than two-thirds the body size of an
adult observed to be in close association with an adult).
Shutdown Procedures
If a marine mammal appears within or enters the relevant EZ, the
airguns must
[[Page 5630]]
be shut down. Following a shutdown, airgun activity must not resume
until the marine mammal has cleared the relevant EZ. The animal is
considered to have cleared the EZ if the following conditions have been
met:
it is visually observed to have departed the EZ;
it has not been seen within the EZ for 15 minutes in the
case of small odontocetes and pinnipeds; or
it has not been seen within the EZ for 30 minutes in the
case of mysticetes and large odontocetes, including sperm and beaked
whales.
Shutdown of the acoustic source is required upon observation of a
species for which authorization has not been granted, or a species for
which authorization has been granted but the authorized number of takes
are met, observed entering or within the Level B harassment zone.
Ramp-Up Procedures
Ramp-up of an acoustic source is intended to provide a gradual
increase in sound levels following a shutdown, enabling animals to move
away from the source if the signal is sufficiently aversive prior to
its reaching full intensity. Ramp-up is required after the array is
shut down for any reason for longer than 15 minutes. Ramp-up must begin
with the activation of the smallest airgun in the array, with
subsequent airgun(s) activated after 5 minute intervals.
Two PSOs are required to monitor during ramp-up. During ramp up,
the PSOs must monitor the EZ, and if marine mammals were observed
within the EZ, a shutdown will be implemented as though the full array
were operational. If airguns have been shut down due to PSO detection
of a marine mammal within or approaching the EZ, ramp-up must not be
initiated until all marine mammals have cleared the EZ, during the day
or night. Criteria for clearing the EZ is described above.
Thirty minutes of pre-clearance observation are required prior to
ramp-up for any shutdown of longer than 30 minutes (e.g., when the
array is shut down during transit from one line to another). This 30-
minute pre-clearance period may occur during any vessel activity (i.e.,
transit). If a marine mammal were observed within or approaching the
relevant EZ during this pre-clearance period, ramp-up must not be
initiated until all marine mammals cleared the EZ. Criteria for
clearing the EZ must be as described above. If the airgun array has
been shut down for reasons other than mitigation (e.g., mechanical
difficulty) for a period of less than 30 minutes, it may be activated
again without ramp-up if PSOs have maintained constant visual
observation and no detections of any marine mammal have occurred within
the EZ or buffer zone. Ramp-up must be planned to occur during periods
of good visibility when possible. However, ramp-up will be allowed at
night and during poor visibility if the 100 m EZ and buffer zone have
been monitored by visual PSOs for 30 minutes prior to ramp-up.
The operator is required to notify a designated PSO of the planned
start of ramp-up as agreed-upon with the lead PSO; the notification
time should not be less than 60 minutes prior to the planned ramp-up. A
designated PSO must be notified again immediately prior to initiating
ramp-up procedures and the operator must receive confirmation from the
PSO to proceed. The operator must provide information to PSOs
documenting that appropriate procedures were followed. Following
deactivation of the array for reasons other than mitigation, the
operator is required to communicate the near-term operational plan to
the lead PSO with justification for any planned nighttime ramp-up.
Vessel Strike Avoidance Measures
Vessel strike avoidance measures are intended to minimize the
potential for collisions with marine mammals. These requirements do not
apply in any case where compliance will 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.
The required measures include the following: Vessel operator and
crew must maintain a vigilant watch for all marine mammals and slow
down or stop the vessel or alter course to avoid striking any marine
mammal. A visual observer aboard the vessel must monitor a vessel
strike avoidance zone around the vessel according to the parameters
stated below. Visual observers monitoring the vessel strike avoidance
zone must be either third-party observers or crew members, but crew
members responsible for these duties must be provided sufficient
training to distinguish marine mammals from other phenomena. Vessel
strike avoidance measures must be followed during surveys and while in
transit.
The vessel must maintain a minimum separation distance of 100 m
from large whales (i.e., baleen whales and sperm whales). If a large
whale is within 100 m of the vessel, the vessel must reduce speed and
shift the engine to neutral, and must not engage the engines until the
whale has moved outside of the vessel's path and the minimum separation
distance has been established. If the vessel is stationary, the vessel
must not engage engines until the whale(s) has moved out of the
vessel's path and beyond 100 m. The vessel must, to the maximum extent
practicable, attempt to maintain a minimum separation distance of 50 m
from all other marine mammals. If an animal is encountered during
transit, the vessel must attempt to remain parallel to the animal's
course, avoiding excessive speed or abrupt changes in course. Vessel
speeds must be reduced to 10 kts or less when mother/calf pairs, pods,
or large assemblages of cetaceans are observed near the vessel.
Based on our evaluation of the applicant's required measures, as
well as other measures considered by NMFS, NMFS has determined that the
required mitigation measures provide the means effecting the least
practicable impact on the affected species or stocks and their habitat,
paying particular attention to rookeries, mating grounds, and areas of
similar significance.
Monitoring and Reporting
In order to issue an IHA for an activity, Section 101(a)(5)(D) of
the MMPA states that NMFS must set forth requirements pertaining to the
monitoring and reporting of such taking. The MMPA implementing
regulations at 50 CFR 216.104 (a)(13) indicate that requests for
authorizations must include the suggested means of accomplishing the
necessary monitoring and reporting that will result in increased
knowledge of the species and of the level of taking or impacts on
populations of marine mammals that are expected to be present in the
planned action 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:
Occurrence of marine mammal species or stocks in the area
in which take is anticipated (e.g., presence, abundance, distribution,
density).
Nature, scope, or context of likely marine mammal exposure
to potential stressors/impacts (individual or cumulative, acute or
chronic), through better understanding of: (1) Action or environment
(e.g., source characterization, propagation, ambient noise); (2)
affected species (e.g., life history, dive patterns); (3) co-occurrence
of marine mammal species with the
[[Page 5631]]
action; or (4) biological or behavioral context of exposure (e.g., age,
calving or feeding areas).
Individual marine mammal responses (behavioral or
physiological) to acoustic stressors (acute, chronic, or cumulative),
other stressors, or cumulative impacts from multiple stressors.
How anticipated responses to stressors impact either: (1)
Long-term fitness and survival of individual marine mammals; or (2)
populations, species, or stocks.
Effects on marine mammal habitat (e.g., marine mammal prey
species, acoustic habitat, or other important physical components of
marine mammal habitat).
Mitigation and monitoring effectiveness.
NSF described a marine mammal monitoring and reporting plan within
their IHA application. Monitoring that is designed specifically to
facilitate mitigation measures, such as monitoring of the EZ to inform
potential shutdowns of the airgun array, are described above and are
not repeated here. NSF's monitoring and reporting plan includes the
following measures:
Vessel-Based Visual Monitoring
As described above, PSO observations must take place during daytime
airgun operations and nighttime start-ups (if applicable) of the
airguns. During seismic operations, three visual PSOs must be based
aboard the Palmer. PSOs must be appointed by NSF with NMFS approval.
The PSOs must have successfully completed relevant training, including
completion of all required coursework and passing a written and/or oral
examination developed for the training program, and must have
successfully attained a bachelor's degree from an accredited college or
university with a major in one of the natural sciences and a minimum of
30 semester hours or equivalent in the biological sciences and at least
one undergraduate course in math or statistics. The educational
requirements may be waived if the PSO has acquired the relevant skills
through alternate training, including (1) secondary education and/or
experience comparable to PSO duties; (2) previous work experience
conducting academic, commercial, or government-sponsored marine mammal
surveys; or (3) previous work experience as a PSO; the PSO should
demonstrate good standing and consistently good performance of PSO
duties.
During seismic operations, one PSO is required to monitor for
marine mammals around the vessel. PSOs must be on duty in shifts of
duration no longer than four hours. Other crew must also be instructed
to assist in detecting marine mammals and in implementing mitigation
requirements (if practical). During daytime, PSOs must scan the area
around the vessel systematically with reticle binoculars (e.g., 7x50
Fujinon) and with the naked eye. At night, PSOs must be equipped with
night-vision equipment.
PSOs must record data to estimate the numbers of marine mammals
exposed to various received sound levels and to document apparent
disturbance reactions or lack thereof. Data must be used to estimate
numbers of animals potentially `taken' by harassment (as defined in the
MMPA). They must also provide information needed to order a shutdown of
the airguns when a marine mammal is within or near the EZ. When a
sighting is made, the following information about the sighting must be
recorded:
(1) Species, group size, age/size/sex categories (if determinable),
behavior when first sighted and after initial sighting, heading (if
consistent), bearing and distance from seismic vessel, sighting cue,
apparent reaction to the airguns or vessel (e.g., none, avoidance,
approach, paralleling, etc.), and behavioral pace; and
(2) Time, location, heading, speed, activity of the vessel, sea
state, visibility, and sun glare.
All observations and shutdowns must be recorded in a standardized
format. Data must be entered into an electronic database. The accuracy
of the data entry must be verified by computerized data validity checks
as the data are entered and by subsequent manual checking of the
database. These procedures allow initial summaries of data to be
prepared during and shortly after the field program and facilitate
transfer of the data to statistical, graphical, and other programs for
further processing and archiving. The time, location, heading, speed,
activity of the vessel, sea state, visibility, and sun glare must also
be recorded at the start and end of each observation watch, and during
a watch whenever there is a change in one or more of the variables.
Results from the vessel-based observations must provide:
(1) The basis for real-time mitigation (e.g., airgun shutdown);
(2) Information needed to estimate the number of marine mammals
potentially taken by harassment, which must be reported to NMFS;
(3) Data on the occurrence, distribution, and activities of marine
mammals in the area where the seismic study is conducted;
(4) Information to compare the distance and distribution of marine
mammals relative to the source vessel at times with and without seismic
activity; and
(5) Data on the behavior and movement patterns of marine mammals
seen at times with and without seismic activity.
Reporting
A draft report must be submitted to NMFS within 90 days after the
end of the survey. The report must describe the operations that were
conducted and sightings of marine mammals near the operations. The
report must provide full documentation of methods, results, and
interpretation pertaining to all monitoring and will summarize the
dates and locations of seismic operations, and all marine mammal
sightings (dates, times, locations, activities, associated seismic
survey activities). The report must also include estimates of the
number and nature of exposures that occurred above the harassment
threshold based on PSO observations, including an estimate of those
that were not detected in consideration of both the characteristics and
behaviors of the species of marine mammals that affect detectability,
as well as the environmental factors that affect detectability.
The draft report 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. A final report must
be submitted within 30 days following the resolution of any comments on
the draft report.
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
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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, 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 the species listed
in Table 1, given that NMFS expects the anticipated effects of the
proposed seismic 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.
NMFS does not anticipate that Level A harassment, serious injury or
mortality will occur as a result of NSF's proposed seismic survey, even
in the absence of proposed mitigation. Thus, the proposed authorization
does not authorize any such takes. As discussed in the Potential
Effects of Specified Activities on Marine Mammals and their Habitat
section in our notice of proposed IHA (84 FR 69950), non-auditory
physical effects, stranding, and vessel strike are not expected to
occur.
No takes by Level A harassment are expected or authorized. As
described above, we expect that marine mammals will be likely to move
away from a sound source that represents an aversive stimulus,
especially at levels that will be expected to result in PTS, given
sufficient notice of the Palmer's approach due to the vessel's
relatively low speed when conducting seismic surveys. The 100-m
exclusion zone encompasses the Level A harassment isopleths for all
marine mammal hearing groups, and is expected to prevent animals from
being exposed to sound levels that will cause PTS. We expect that any
instances of take will be in the form of short-term Level B behavioral
harassment in the form of temporary avoidance of the area or decreased
foraging (if such activity were occurring), reactions that are
considered to be of low severity and with no lasting biological
consequences (e.g., Southall et al., 2007).
Marine mammal habitat may be impacted by elevated sound levels, but
these impacts will be temporary. Feeding behavior is not likely to be
significantly impacted, as marine mammals appear to be less likely to
exhibit behavioral reactions or avoidance responses while engaged in
feeding activities (Richardson et al., 1995). Prey species are mobile
and are broadly distributed throughout the project area; therefore,
marine mammals that may be temporarily displaced during survey
activities are expected to be able to resume foraging once they have
moved away from areas with disturbing levels of underwater noise.
Because of the temporary nature of the disturbance, the availability of
similar habitat and resources in the surrounding area, and the lack of
important or unique marine mammal habitat, 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. In addition, there are no feeding, mating
or calving areas known to be biologically important to marine mammals
within the proposed project area.
The activity is expected to impact a very small percentage of all
marine mammal populations that will be affected by NSF's planned survey
(less than 13 percent each for all marine mammal populations combined).
Additionally, the acoustic ``footprint'' of the planned survey will be
very small relative to the ranges of all marine mammal species that
will potentially be affected. Sound levels will increase in the marine
environment in a relatively small area surrounding the vessel compared
to the range of the marine mammals within the planned survey area. This
includes the small amount of icebreaking, hours at most, expected. The
effects of icebreaking are transitory, localized, and constrained to a
relatively narrow swath to each side of the vessel. The seismic array
will be active 24 hours per day throughout the duration of the proposed
survey. However, the very brief overall duration of the planned survey
(eight days) will further limit potential impacts that may occur as a
result of the proposed activity.
The planned mitigation measures are expected to reduce the number
and/or severity of takes by allowing for detection of marine mammals in
the vicinity of the vessel by visual observers, and by minimizing the
severity of any potential exposures via shutdowns of the airgun array.
Based on previous monitoring reports for substantially similar
activities that have been previously authorized by NMFS, we expect that
the required mitigation will be effective in minimizing impacts.
Of the marine mammal species under our jurisdiction that are likely
to occur in the project area, the following species are listed as
endangered under the ESA: blue, fin, sei, and sperm whales. Given the
very low numbers of takes for these species (Table 9), relative to
their population sizes, as well as the type of take (Level B
harassment) we do not expect population-level impacts to any of these
species. The other marine mammal species that may be taken by
harassment during NSF's seismic survey and icebreaking activities are
not listed as threatened or endangered under the ESA. There is no
designated critical habitat for any ESA-listed marine mammals within
the project area; of the non-listed marine mammals for which we
authorize take, none are considered ``depleted'' by NMFS under the
MMPA.
NMFS concludes that exposures to marine mammal species due to NSF's
planned seismic survey will result in only short-term (temporary and
short in duration) effects to individuals exposed, or some small degree
of PTS to a very small number of individuals. Marine mammals 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. NMFS does not
anticipate the authorized take estimates to impact annual rates of
recruitment or survival.
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:
No mortality or serious injury is anticipated or
authorized;
No take by Level A harassment is anticipated or
authorized;
The anticipated impacts of the proposed activity on marine
mammals will primarily be temporary behavioral changes of small
percentages of the affected species due to avoidance of the area around
the survey vessel. The
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relatively short duration of the proposed survey (10 days; eight days
of survey plus two contingency days) will further limit the potential
impacts of any temporary behavioral changes that will occur;
The availability of alternate areas of similar habitat
value for marine mammals to temporarily vacate the survey area during
the proposed survey to avoid exposure to sounds from the activity;
The proposed project area does not contain areas of
significance for feeding, mating or calving;
The potential adverse effects on fish or invertebrate
species that serve as prey species for marine mammals from the proposed
survey will be temporary and spatially limited; and
The planned mitigation measures, including visual and
acoustic monitoring and shutdowns, are expected to minimize potential
impacts to marine mammals.
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 monitoring and
mitigation measures, NMFS finds that the total marine mammal take from
the proposed 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 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. Additionally, other qualitative
factors may be considered in the analysis, such as the temporal or
spatial scale of the activities.
Marine mammals in the survey area are not assigned to NMFS stocks.
For purposes of the small numbers analysis, we rely on the best
available information on the abundance estimates for the species of
marine mammals that could be taken. The numbers of marine mammals that
we authorize to be taken will be considered small relative to the
relevant populations (less than 13 percent for all species).
Based on the analysis contained herein of the planned activity
(including the required mitigation and monitoring measures) and the
authorized take of marine mammals, NMFS concludes that small numbers of
marine mammals will be taken relative to the population sizes of the
affected species or stocks.
Unmitigable Adverse Impact Analysis and Determination
There are no relevant subsistence uses of the affected marine
mammal stocks or species implicated by this action. Therefore, NMFS has
determined that the total taking of affected species or stocks will not
have an unmitigable adverse impact on the availability of such species
or stocks for taking for subsistence purposes.
National Environmental Policy Act
To comply with the National Environmental Policy Act of 1969 (NEPA;
42 U.S.C. 4321 et seq.) and NOAA Administrative Order (NAO) 216-6A,
NMFS must review our proposed action (i.e., the issuance of an
incidental harassment authorization) with respect to potential impacts
on the human environment.
This action is consistent with categories of activities identified
in Categorical Exclusion B4 (incidental harassment authorizations with
no anticipated serious injury or mortality) of the Companion Manual for
NOAA Administrative Order 216-6A, which do not individually or
cumulatively have the potential for significant impacts on the quality
of the human environment and for which we have not identified any
extraordinary circumstances that will preclude this categorical
exclusion. Accordingly, NMFS has determined that the issuance of the
IHA qualifies to be categorically excluded from further NEPA review.
Endangered Species Act (ESA)
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, in this case with the ESA Interagency
Cooperation Division, whenever we propose to authorize take for
endangered or threatened species.
The NMFS Office of Protected Resources Interagency Cooperation
Division issued a Biological Opinion on January 23, 2020, under section
7 of the ESA, on the issuance of an IHA to NSF under section
101(a)(5)(D) of the MMPA by the NMFS Office of Protected Resources
Permits and Conservation Division. The Biological Opinion concluded
that the proposed action is not likely to jeopardize the continued
existence of blue, fin, sei, and sperm whales, and is not likely to
destroy or modify critical habitat of listed species because no
critical habitat exists for these species in the action area.
Authorization
As a result of these determinations, NMFS has issued an IHA to NSF
for conducting the specified activity in the Amundsen Sea, provided the
previously mentioned mitigation, monitoring, and reporting requirements
are incorporated.
Dated: January 27, 2019.
Donna S. Wieting,
Director, Office of Protected Resources, National Marine Fisheries
Service.
[FR Doc. 2020-01811 Filed 1-30-20; 8:45 am]
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