[Federal Register Volume 83, Number 125 (Thursday, June 28, 2018)]
[Notices]
[Pages 30480-30524]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2018-13732]
[[Page 30479]]
Vol. 83
Thursday,
No. 125
June 28, 2018
Part II
Department of Commerce
-----------------------------------------------------------------------
National Oceanic and Atmospheric Administration
-----------------------------------------------------------------------
Takes of Marine Mammals Incidental to Specified Activities; Taking
Marine Mammals Incidental to a Marine Geophysical Survey in the North
Pacific Ocean; Notice
Federal Register / Vol. 83 , No. 125 / Thursday, June 28, 2018 /
Notices
[[Page 30480]]
-----------------------------------------------------------------------
DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
RIN 0648-XG144
Takes of Marine Mammals Incidental to Specified Activities;
Taking Marine Mammals Incidental to a Marine Geophysical Survey in the
North Pacific Ocean
AGENCY: National Marine Fisheries Service (NMFS), National Oceanic and
Atmospheric Administration (NOAA), Commerce.
ACTION: Notice; proposed incidental harassment authorization; request
for comments.
-----------------------------------------------------------------------
SUMMARY: NMFS has received a request from the Lamont-Doherty Earth
Observatory of Columbia University (L-DEO) for authorization to take
marine mammals incidental to a marine geophysical survey in the North
Pacific Ocean. Pursuant to the Marine Mammal Protection Act (MMPA),
NMFS is requesting comments on its proposal to issue an incidental
harassment authorization (IHA) to incidentally take marine mammals
during the specified activities. NMFS will consider public comments
prior to making any final decision on the issuance of the requested
MMPA authorization and agency responses will be summarized in the final
notice of our decision.
DATES: Comments and information must be received no later than July 30,
2018.
ADDRESSES: Comments should be addressed to Jolie Harrison, Chief,
Permits and Conservation Division, Office of Protected Resources,
National Marine Fisheries Service. Physical comments should be sent to
1315 East-West Highway, Silver Spring, MD 20910 and electronic comments
should be sent to [email protected].
Instructions: NMFS is not responsible for comments sent by any
other method, to any other address or individual, or received after the
end of the comment period. Comments received electronically, including
all attachments, must not exceed a 25-megabyte file size. Attachments
to electronic comments will be accepted in Microsoft Word or Excel or
Adobe PDF file formats only. All comments received are a part of the
public record and will generally be posted online at https://www.fisheries.noaa.gov/node/23111 without change. All personal
identifying information (e.g., name, address) voluntarily submitted by
the commenter may be publicly accessible. Do not submit confidential
business information or otherwise sensitive or protected information.
FOR FURTHER INFORMATION CONTACT: Rob Pauline, 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/node/23111. In case of problems accessing these
documents, please call the contact listed above.
SUPPLEMENTARY INFORMATION:
Background
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
authorization is provided to the public for review.
An authorization for incidental takings shall be granted if NMFS
finds that the taking will have a negligible impact on the species or
stock(s), will not have an unmitigable adverse impact on the
availability of the species or stock(s) for subsistence uses (where
relevant), and if the permissible methods of taking and requirements
pertaining to the mitigation, monitoring and reporting of such takings
are set forth.
NMFS has defined ``negligible impact'' in 50 CFR 216.103 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.
The MMPA states that the term ``take'' means to harass, hunt,
capture, kill or attempt to harass, hunt, capture, or kill any marine
mammal.
Except with respect to certain activities not pertinent here, 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).
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.
Accordingly, NMFS plans to adopt the National Science Foundation's
EA, provided our independent evaluation of the document finds that it
includes adequate information analyzing the effects on the human
environment of issuing the IHA. We will review all comments submitted
in response to this notice prior to concluding our NEPA process or
making a final decision on the IHA request.
Summary of Request
On March 16, 2018, NMFS received a request from the L-DEO for an
IHA to take marine mammals incidental to conducting a marine
geophysical survey in the North Pacific Ocean. L-DEO submitted a
revised application on June 11, 2018. On June 13, 2018 we deemed L-
DEO's application for authorization to be adequate and complete. L-
DEO's request is for take of small numbers of 39 species of marine
mammals by Level A and Level B harassment. Underwater sound associated
with airgun use may result in the behavioral harassment or auditory
injury of marine mammals in the ensonified areas. Mortality is not an
anticipated outcome of airgun surveys such as this, and, therefore, an
IHA is appropriate. The planned activity is not expected to exceed one
year, hence, we do not expect subsequent MMPA incidental harassment
authorizations would be issued for this particular activity.
Description of Proposed Activity
Overview
The specified activity consists of two high-energy seismic surveys
conducted at different locations in the North Pacific Ocean.
Researchers from Lamont-Doherty Earth Observatory (L-DEO) and
University of Hawaii, with funding from the U.S. National Science
Foundation (NSF), in collaboration with researchers from United States
Geological Survey (USGS), Oxford University, and GEOMAR Helmholtz
Centre for Ocean Research Kiel (GEOMAR), propose to conduct the surveys
from the Research Vessel (R/V) Marcus G. Langseth (Langseth) in the
North Pacific Ocean. The NSF-owned Langseth is operated by Columbia
University's L-DEO under an existing
[[Page 30481]]
Cooperative Agreement. The first proposed seismic survey would occur in
the vicinity of the Main Hawaiian Islands, and a subsequent survey
would take place at the Emperor Seamounts in 2019. The proposed timing
for the Hawaii survey is summer/early fall 2018; the timing for the
Emperor Seamounts survey would likely be spring/early summer 2019. Both
surveys would use a 36-airgun towed array with a total discharge volume
of ~6,600 in\3\.
The main goal of the surveys proposed by L-DEO and the University
of Hawaii is to gain fundamental insight into the formation and
evaluation of Hawaiian-Emperor Seamount chain, and inform a more
comprehensive assessment of geohazards for the Hawaiian Islands region.
Dates and Duration
The Hawaii survey would be expected to last for 36 days, including
~19 days of seismic operations, 11 days of equipment deployment/
retrieval, ~3 days of operational contingency time (e.g., weather
delays, etc.), and ~3 days of transit. The Langseth would leave out of
and return to port in Honolulu during summer (likely mid-August) 2018.
The Emperor Seamounts survey would be expected to last 42 days,
including ~13 days of seismic operations, ~11 days of equipment
deployment/retrieval, ~5.5 days of operational contingency time, and
12.5 days of transit. The Langseth would leave Honolulu and return to
port likely in Adak or Dutch Harbor, Alaska. The dates for this cruise
have not yet been determined, although late spring/early summer 2019 is
most likely.
Specific Geographic Region
The specified activity consists of two seismic surveys in the North
Pacific Ocean--one at the Main Hawaiian Islands (Fig. 1 in application)
and the other at the Emperor Seamounts (Fig. 2 in application). The
proposed Hawaii survey would occur within ~18-24[deg] N, ~153-160[deg]
W, and the proposed Emperor Seamounts survey would occur within ~43-
48[deg] N, ~166-173[deg] E. The Hawaiian-Emperor Seamount chain is a
mostly undersea mountain range in the Pacific Ocean that reaches above
sea level in Hawaii. It is composed of the Hawaiian ridge, consisting
of the islands of the Hawaiian chain northwest to Kure Atoll, and the
Emperor Seamounts: Together they form a vast underwater mountain region
of islands and intervening seamounts, atolls, shallows, banks and reefs
along a line trending southeast to northwest beneath the northern
Pacific Ocean. The seamount chain, containing over 80 identified
undersea volcanoes, stretches over 5,800 kilometers (km) or 3,600 miles
(mi) from the Aleutian Trench in the far northwest Pacific to the
Lo[revaps]ihi seamount, the youngest volcano in the chain, which lies
about 35 km (22 mi) southeast of the Island of Hawaii. The Emperor
Seamounts seismic survey location is located approximately 4,100 km
(2,200 mi) northwest of the Hawaii seismic survey location.
Representative survey tracklines are shown in Figures 1 and 2 in
the application. As described further in this document, however, some
deviation in actual track lines, including order of survey operations,
could be necessary for reasons such as science drivers, poor data
quality, inclement weather, or mechanical issues with the research
vessel and/or equipment. Thus, for the Emperor Seamounts survey, the
tracklines could occur anywhere within the coordinates noted above and
illustrated by the box in the inset map on Figure 2. The tracklines for
the Hawaii survey could shift slightly, but would stay within the
coordinates noted above and general vicinity of representative lines
depicted in Figure 1. Water depths in the proposed Hawaii survey area
range from ~700 to more than 5,000 m. The water depths in the Emperor
Seamounts survey area range from 1,500-6,000 m. The proposed Hawaii
seismic survey would be conducted within the U.S. exclusive economic
zone (EEZ); the Emperor Seamounts survey would take place in
International Waters.
Detailed Description of Specific Activity
The procedures to be used for the proposed surveys would be similar
to those used during previous seismic surveys by L-DEO and would use
conventional seismic methodology. The surveys would involve one source
vessel, the Langseth, which is owned by NSF and operated on its behalf
by Columbia University's L-DEO. The Langseth would deploy an array of
36 airguns as an energy source with a total volume of ~6,600 in\3\. The
receiving system would consist of OBSs and a single hydrophone streamer
15 km in length and OBSs. As the airgun arrays are towed along the
survey lines, the hydrophone streamer would transfer the data to the
on-board processing system, and the OBSs would receive and store the
returning acoustic signals internally for later analysis.
The proposed study consists of two seismic surveys in the North
Pacific Ocean. There would be a total of four seismic transects for the
Hawaii survey--two North (N)-South (S) tracklines (Lines 1 and 2), and
two East (E)-West (W) tracklines (Lines 3 and 4). An optional trackline
(Line 5) could be acquired instead of Line 4 (Fig. 1). Lines 1 and 2
would be acquired twice--seismic refraction data would be acquired
first, followed by multichannel seismic (MCS) reflection data. Only MCS
reflection profiling would occur along Lines 3, 4, or 5. The location
of the E-W tracklines (Lines 3, 4, or 5) could shift from what is
currently depicted in Figure 1 depending on the science objectives;
however, the E-W lines would remain in water >3,200 m deep.
The Langseth would first deploy 70 ocean bottom seismometers (OBS)s
required for the refraction profiling--the vessel would transit from
Honolulu to the north end of Line 2, deploy 35 OBSs along Line 2, ~15
km apart, and then transit to the south end of Line 1 to deploy 35 OBSs
(~15 km apart) along Line 1. The streamer and airgun array would then
be deployed. Refraction data would then be acquired from north to south
on Line 1 followed by MCS profiling along the same line. If Lines 3 and
4 are to be surveyed (preferred option), MCS profiles would then be
acquired along Line 3, followed by refraction data acquisition in a
north-south direction along Line 2, followed by MCS profiles along Line
2 from south to north. The vessel would then acquire MCS profiles from
the north end of Line 2 to the west end of Line 4, and along Line 4.
After seismic acquisition ceases, the streamer, airgun source, and all
OBSs would be recovered by the Langseth.
There would be three seismic transects for the Emperor Seamounts
survey (Fig. 2). Data would be acquired twice along the two OBS lines--
once for seismic refraction data and once for MCS reflection profiling.
Only MCS reflection profiling would occur along the third transect that
connects the two OBS lines. The Langseth would first acquire MCS
reflection data for all three lines--from north to south, then along
the connecting transect, and from west to east. After recovering the
streamer and airgun array, the Langseth would deploy 32 OBSs required
for the refraction profiling from east to west along the first line.
After seismic acquisition along the first OBS line from west to east,
the OBSs would be recovered and re-deployed along the second OBS line,
which would then be surveyed from north to south. The Langseth would
then recover all OBSs, the streamer, and the airgun array.
In addition to the operations of the airgun array, a multibeam
echosounder (MBES), a sub-bottom profiler (SBP), and an Acoustic
Doppler Current
[[Page 30482]]
Profiler (ADCP) would be operated from the Langseth continuously during
the seismic surveys, but not during transit to and from the survey
areas. All planned geophysical data acquisition activities would be
conducted by L-DEO with on-board assistance by the scientists who have
proposed the studies. The vessel would be self-contained, and the crew
would live aboard the vessel.
During the two surveys, the Langseth would tow the full array,
consisting of four strings with 36 airguns (plus 4 spares) and a total
volume of ~6,600 in\3\. The 4-string array would be towed at a depth of
12 m, and the shot intervals would range from 50 m for MCS acquisition
and 150 m for OBS acquisition. To retrieve OBSs, an acoustic release
transponder (pinger) is used to interrogate the instrument at a
frequency of 8-11 kHz, and a response is received at a frequency of
11.5-13 kHz. The burn-wire release assembly is then activated, and the
instrument is released to float to the surface from the anchor which is
not retrieved.
Proposed mitigation, monitoring, and reporting measures are
described in detail later in this document (please see ``Proposed
Mitigation'' and ``Proposed Monitoring and Reporting'').
Description of Marine Mammals in the Area of the Specified Activity
Section 4 of the IHA application summarizes available information
regarding status and trends, distribution and habitat preferences, and
behavior and life history of the potentially affected species. More
general information about these species (e.g., physical and behavioral
descriptions) may be found on NMFS' website (https://www.fisheries.noaa.gov/find-species).
Table 1 lists all species with expected potential for occurrence in
the North Pacific Ocean and summarizes information related to the
population, including regulatory status under the MMPA and ESA. Some of
the populations of marine mammals considered in this document occur
within the U.S. EEZ and are therefore assigned to stocks and are
assessed in NMFS' Stock Assessment Reports (www.nmfs.noaa.gov/pr/sars/
). 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.
Twenty-eight cetacean species, including 21 odontocetes (dolphins
and small- and large-toothed whales) and seven mysticetes (baleen
whales), and one pinniped species, could occur in the proposed Hawaii
survey area (Table 4). In the Emperor Seamounts survey area, 27 marine
mammal species could occur, including 15 odontocetes (dolphins and
small- and large-toothed whales), eight mysticetes (baleen whales), and
four pinniped species. Some species occur in both locations. In total,
39 species are expected to occur in the vicinity of the specified
activity.
Baird et al. (2015) described numerous Biologically Important Areas
(BIAs) for cetaceans for the Hawaii region. BIAs were identified for
small resident populations of cetaceans based on sighting data, photo-
identification, genetics, satellite tagging, and expert opinion, and
one reproductive area for humpbacks was identified as a BIA; these are
described in the following section for each marine mammal species. The
BIAs range from ~700-23,500 km\2\ in area (Baird et al. 2015).
Marine mammal abundance estimates presented in this document
represent the total number of individuals estimated within a particular
study or survey area. All values presented in Table 1 are the most
recent available at the time of publication.
Table 1--Marine Mammals That Could Occur in the Proposed Survey Areas
--------------------------------------------------------------------------------------------------------------------------------------------------------
Present at time of
ESA/MMPA Stock abundance survey (Y/N)
Common name Scientific name Stock status; (CV, Nmin, most PBR Annual M/----------------------
strategic (Y/ recent abundance SI \3\ Emperor
N) \1\ survey) \2\ HI Seamounts
--------------------------------------------------------------------------------------------------------------------------------------------------------
Order Cetartiodactyla--Cetacea--Superfamily Mysticeti (baleen whales)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Family Eschrichtiidae:
Gray whale.................. Eschrichtius Western North E/D; Y....... 140 (0.04, 135, 0.06 unk N Y
robustus. Pacific. 2011) \4\.
Family Balaenidae:
North Pacific right whale... Eubalaena japonica. Eastern North E/D; Y....... 31 (0.226, 26, N/A 0 N Y
Pacific. 2013) \6\.
N/A................ ............. 450 \5\........... ........ ........
Family Balaenopteridae
(rorquals):
Humpback whale.............. Megaptera Central North -/-; N....... 10,103 (0.03, 83 25 Y Y
novaeangliae. Pacific. 7,890, 2006) \6\.
Western North E/D; Y....... 1,107 (0.30, 3 3.2
Pacific. 865,2006) \6\.
Minke whale................. Balaenoptera Hawaii............. ............. UNK............... ........ ........ N Y
acutorostrata. N/A................ ............. 22,000 \7\........ ........ ........
Bryde's whale............... (Balaenoptera edeni/ Hawaii............. -/-; N....... 1,751 (0.29, 13.8 0 Y Y
brydei. Eastern Tropical -/-; N--..... 1,378, 2010) \17\. UND ........
Pacific. UNK...............
Sei whale................... Balaenoptera Hawaii............. E/D; Y....... 178 (0.9, 93, 0.2 0.2 Y Y
borealis. 2010) \4\.
Fin whale................... Balaenoptera Hawaii............. E/D; Y....... 154 (1.05, 75, 0.1 0 Y Y
physalus physalus. N/A................ ............. 2010) \17\. ........ ........
13,620-18,680 \9\.
Blue whale.................. Balaenoptera Central North E/D; Y....... 133 (1.09, 63, 0.1 0 Y Y
musculus musculus). Pacific. 2010) \17\.
--------------------------------------------------------------------------------------------------------------------------------------------------------
Superfamily Odontoceti (toothed whales, dolphins, porpoises)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Family Physeteridae:
[[Page 30483]]
Sperm whale................. Physeter Hawaii............. E/D; Y....... 4,559 (0.33, 13.9 0.7 Y Y
macrocephalus. N/A................ N/A.......... 3,478, 2010) \17\. ........ ........
29,674 \10\-26,300
\11\.
Family Kogiidae:
Pygmy sperm whale........... Kogia breviceps.... Hawaii............. -/-; N....... 7,138 \4\......... UND 0 Y Y
Dwarf sperm whale........... Kogia sima......... Hawaii............. -/-; N....... 17,519 \4\........ UND 0 Y Y
Family Ziphiidae (beaked
whales):
Cuvier's beaked whale....... Ziphius cavirostris Hawaii............. -, -, N...... 723 (0.69, 428, 4.3 0 Y Y
2010) \17\.
N/A................ ............. 20,000 \12\....... ........ ........
Longman's beaked whale...... Indopacetus Hawaii............. -, -, N...... 7,619 (0.66, 46 0 Y N
pacificus. 4,592, 2010) \17\.
Blainville's beaked whale... Mesoplodon Hawaii............. -, -, N...... 2,105 (1.13,1, 10 0 Y N
densirostris. 980, 2010) \17\.
Stejneger's beaked whale.... Mesoplodon Alaska............. N............ UNK............... UND 0 N Y
stejnegeri.
Ginkgo-toothed beaked whale. Mesoplodon N/A................ ............. 25,300 \12\....... ........ ........ Rare Absent
ginkgodens.
Deraniyagala's beaked whale. Mesoplodon hotaula. N/A................ ............. 25,300 \12\....... ........ ........ Y N
Hubb's beaked whale......... Mesoplodon N/A................ ............. 25,300 \12\....... ........ ........ Y N
carlhubbsi.
Baird's beaked whale........ Berardius bairdii.. N/A................ ............. 10,190 \13\....... ........ ........ N Y
Family Delphinidae:
Rough-toothed dolphin....... Steno bredanensis.. Hawaii............. -, -, N...... 72,528 (0.39, 46 UNK Common N
52,033, 2010)
\17\.
Common bottlenose dolphin... Tursiops truncatus. Hawaii Pelagic..... -/-; N....... 21,815 (0.57, 140 0.2 Common N
13,957, 2010)
\17\.
Kaua[revaps]i and -/-; N....... 184 (0.11, 168, 1.7 unk Common N
Ni[revaps]ihau. 2005) \4\.
O[revaps]ahu....... -/-; N....... 743 (0.54, 485, 4.9 unk Common N
2006) \4\.
4 Islands Region... -/-; N....... 191 (0.24, 156, unk unk Common N
2006).
Hawaii Island...... -/-; N....... 128 (0.13, 115, 1.6 unk Common N
2006) \4\.
Common dolphin.............. Delphinus delphis.. N/A................ ............. 2,963,000 \14\.... ........ ........ N Y
Pantropical spotted dolphin. Stenella attenuata. Hawaii Pelagic..... -/-; N....... 55,795 (0.40, 403 0 Y N
40,338, 2010)
\17\.
O[revaps]ahu....... -/-; N....... unk............... unk unk
4 Island Region.... -/-; N....... unk............... unk unk
Hawaii Island...... -/-; N....... unk............... unk >= 0.2
Spinner dolphin............. Stenella Hawaii Pelagic..... -/-; N....... unk............... unk unk Y N
longirostris.
Hawaii Island...... -/-; N....... 631 (0.04, 585, 5.9 unk Common N
2013) \4\.
O[revaps]ahu/4- -/-; N....... 355 (0.09, 329, 3.3 unk Y N
Islands. 2013) \4\.
Striped dolphin............. Stenella Hawaii............. -/-; N....... 61,021 (0.38, 449 unk Y Y
coeruleoalba. 44,922, 2010)
\17\.
N/A................ ............. 964,362 \15\...... ........ ........
Fraser's dolphin............ Lagenodelphis hosei Hawaii............. -/-; N....... 51,491 (0.66, 310 0 Y N
31,034, 2010)
\17\.
Pacific white-sided dolphin. Lagenorhynchus Central North ............. 988,333 \16\...... ........ ........ N Y
obliquidens. Pacific.
Northern right whale dolphin Lissodelphis N/A................ ............. 307,784 \16\...... ........ ........ N Y
borealis.
Risso's dolphin............. Grampus griseus.... Hawaii............. -/-; N....... 11,613 (0.39, 82 0 Y Y
8,210, 2010) \17\.
N/A................ ............. 110,457 \15\...... ........ ........
Melon-headed whale.......... Peponocephala Hawaii............. -/-; N....... 8,666 (1.00, 43 0 Y N
electra. Kohala Resident.... -/-; N....... 4,299, 2010) \17\. 4 0
447 (0.12, 404,
2009) \4\.
Pygmy killer whale.......... Feresa attenuata... Hawaii............. -/-; N....... 10,640 (0.53, 56 1.1 Y N
6,998, 2010) \17\.
False killer whale.......... Pseudorca Hawaii Insular..... E/D;Y........ 167 (0.14, 149, 0.3 0 Y Y
crassidens. 2015) \17\.
Northwest Hawaiian -/-; N....... 617 (1.11, 290, 2.3 0.4
Islands. 2010) \17\.
Hawaii Pelagic..... -/-; N....... 1,540 (0.66, 928, 9.3 7.6
2010) \17\.
N/A................ ............. 16,668 \18\....... ........ ........
Killer whale................ Orcinus orca....... Hawaii............. -/-; N....... 146 (0.96, 74, 0.7 0 Y Y
2010).
N/A................ ............. 8,500 \19\........ ........ ........
Short-finned pilot whale.... Globicephala Hawaii............. -/-; N....... 19,503 (0.49, 106 0.9 Y Y
macrorhynchus. N/A................ ............. 13,197, 2010).
53,608 \16\.......
Family Phoenidae (porpoises):
Dall's porpoise............. Phocoenoides dalli. N/A................ ............. 1,186,000 \20\.... ........ ........ N Y
--------------------------------------------------------------------------------------------------------------------------------------------------------
Order Carnivora--Superfamily Pinnipedia
--------------------------------------------------------------------------------------------------------------------------------------------------------
Family Otariidae (eared seals
and sea lions):
Steller sea lion............ Eumetopias jubatus. Western DPS........ E/D; Y....... 50,983 (-,50,983, ........ ........ N Y
2015).
Northern fur seal........... Callorhinus ursinus Eastern Pacific.... -/D; Y....... 626,734 (0.2, 11,405 437 N Y
530,474, 2014).
N/A................ ............. 1,100,000 \5\..... ........ ........
[[Page 30484]]
Family Phocidae (earless seals):
Hawaiian monk seal.......... Neomonachus Hawaii............. E/D; Y....... 1,324 (0.03, 4.4 >=1.6 Y N
schauinslandi. 1,261, 2015) \17\.
Northern elephant seal...... Mirounga ................... ............. 210,000-239,000 ........ ........ N Y
angustirostris. \21\.
Ribbon seal................. Histriophoca Alaska............. -/-; N....... 184,000 (0.12, 9,785 3.8 N Y
fasciata. 163,000, 2013).
--------------------------------------------------------------------------------------------------------------------------------------------------------
\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: www.nmfs.noaa.gov/pr/sars/. CV is coefficient of variation; Nmin is the minimum estimate of
stock abundance.
\3\--These values, found in NMFS's SARs, represent annual levels of human-caused mortality plus serious injury from all sources combined (e.g.,
commercial fisheries, ship strike). Annual M/SI often cannot be determined precisely and is in some cases presented as a minimum value or range. A CV
associated with estimated mortality due to commercial fisheries is presented in some cases.
\4\--Carretta et al., 2017.
\5\--Jefferson et al., 2015.
\6\--Muto et al., 2017.
\7\--IWC 2018.
\8\--Central and Eastern North Pacific (Hakamada and Matsuoka 2015a).
\9\--Ohsumi and Wada, 1974.
\10\--Whitehead 2002.
\11\--Barlow and Taylor 2005.
\12\--Wade and Gerrodette 1993.
\13\--Western Pacific Ocean (Okamura et al., 2012).
\14\--ETP (Gerrodette and Forcada 2002 in Hammond et al., 2008b).
\15\--Gerrodette et al., 2008.
\16\--North Pacific (Miyashita 1993b).
\17\--Carretta et al., 2018.
\18\--Western North Pacific (Miyashita 1993a).
\19\--Ford 2009.
\20\--Buckland et al., 1993.
\21\--Lowry et al., 2014.
Note--Italicized species are not expected to be taken or proposed for authorization.
All species that could potentially occur in the proposed survey
area are included in Table 1. With the exception of Steller sea lions,
these species or stocks temporally and spatially co-occur with the
activity to the degree that take is reasonably likely to occur.
However, the temporal and/or spatial occurrence of Steller sea lions is
such that take is not expected to occur, and they are not discussed
further beyond the explanation provided here. The Steller sea lion
occurs along the North Pacific Rim from northern Japan to California
(Loughlin et al. 1984). They are distributed around the coasts to the
outer shelf from northern Japan through the Kuril Islands and Okhotsk
Sea, through the Aleutian Islands, central Bering Sea, southern Alaska,
and south to California (NMFS 2016c). There is little information
available on at-sea occurrence of Steller sea lions in the northwestern
Pacific Ocean. The Emperor Seamounts survey area is roughly 1,200
kilometers away from the Aleutian Islands in waters 2,000 to more than
5,000 meters deep. Steller sea lions are unlikely to occur in the
proposed offshore survey area based on their known distributional range
and habitat preference. Therefore, it is extremely unlikely that
Steller sea lions would be exposed to the stressors associated with the
proposed seismic activities and will not be discussed further.
We have reviewed L-DEO's species descriptions, including life
history information, distribution, regional distribution, diving
behavior, and acoustics and hearing, for accuracy and completeness.
Below, for the 39 species that are likely to be taken by the activities
described, we offer a brief introduction to the species and relevant
stock as well as available information regarding population trends and
threats, and describe any information regarding local occurrence.
Gray Whale
Two separate populations of gray whales have been recognized in the
North Pacific (LeDuc et al. 2002): The eastern North Pacific and
western North Pacific (or Korean-Okhotsk) stocks. However, the
distinction between these two populations has been recently debated
owing to evidence that whales from the western feeding area also travel
to breeding areas in the eastern North Pacific (Weller et al. 2012,
2013; Mate et al. 2015). Thus, it is possible that whales from both the
endangered Western North Pacific and the delisted Eastern North Pacific
DPS could occur in the proposed survey area in the Emperor Seamounts
survey area.
The western population is known to feed in the Okhotsk Sea along
the northeast coast of Sakhalin Island (Weller et al. 1999, 2002a,
2008), eastern Kamchatka, and the northern Okhotsk Sea in the summer
and autumn (Vladimirov et al. 2008). Winter breeding grounds are not
known; however, it has been postulated that wintering areas occur along
the south coast of the Korean Peninsula, but it is more likely that
they are located in the South China Sea, along the coast of Guangdong
province and Hainan (Wang 1984 and Zhu 1998 in Weller et al. 2002a;
Rice 1998). Winter records exist for Japan, North Korea, and South
Korea (Weller et al. 2002a,b). Migration into the Okhotsk Sea may occur
through the Sea of Japan via the Tatar Strait and/or La Perouse Strait
(see Reeves et al. 2008). If migration timing is similar to that of the
better-known eastern gray whale, southbound migration probably occurs
mainly in December-January and northbound migration mainly in February-
April, with northbound migration of newborn calves and their mothers
probably concentrated at the end of that period. The eastern North
Pacific gray whale breeds and winters in
[[Page 30485]]
Baja, California, and migrates north to summer feeding grounds in the
northern Bering Sea, Chukchi Sea, and western Beaufort Sea (Rice and
Wolman 1971; Jefferson et al. 2015).
In the western North Pacific, gray whales migrate along the coast
of Japan (Weller et al. 2008), and records have been reported there
from November through August, with the majority for March through May
(Weller et al. 2012). Although the offshore limit of this route is not
well documented, gray whales are known to prefer nearshore coastal
waters. However, some exchange between populations in the eastern and
western North Pacific has been reported (Weller et al. 2012, 2013; Mate
et al. 2015); thus, migration routes could include pelagic waters of
the Pacific Ocean, including the proposed Emperor Seamounts survey
area. Nonetheless, given their small population size and preference for
nearshore waters, only very small numbers are likely to be encountered
during the proposed Emperor Seamounts survey during any time of the
year. Additionally, during summer, most gray whales would be feeding
near Sakhalin Island. The gray whale does not occur in Hawaiian waters.
North Pacific Right Whale
North Pacific right whales summer in the northern North Pacific,
primarily in the Okhotsk Sea (Brownell et al. 2001) and in the Bering
Sea (Shelden et al. 2005; Wade et al. 2006). The eastern North Pacific
stock that occurs in U.S. waters numbers only ~31 individuals (Wade et
al. 2011), and critical habitat has been designated in the eastern
Bering Sea and in the Gulf of Alaska, south of Kodiak Island (NMFS
2017b). Wintering and breeding areas are unknown, but have been
suggested to include the Hawaiian Islands, Ryukyu Islands, and Sea of
Japan (Allen 1942; Gilmore 1978; Reeves et al. 1978; Herman et al.
1980; Omura 1986). The Hawaiian Islands were not a major calving ground
for right whales in the last 200 years, but mid-ocean whaling records
of right whales during winter suggest that right whales may have
wintered and calved far offshore in the Pacific Ocean (Scarff 1986,
1991; Clapham et al. 2004). In April 1996, a right whale was sighted
off Maui, the first documented sighting of a right whale in Hawaiian
waters since 1979 (Salden and Mickelsen 1999).
Whaling records indicate that right whales once ranged across the
entire North Pacific Ocean north of 35[deg] N and occasionally occurred
as far south as 20[deg] N (e.g., Scarff 1986, 1991). In the western
Pacific, most sightings in the 1900s were reported from Japanese
waters, followed by the Kuril Islands, and the Okhotsk Sea (Brownell et
al. 2001). Significant numbers of right whales have been seen in the
Okhotsk Sea during the 1990s, suggesting that the adjacent Kuril
Islands and Kamchatka coast are a major feeding ground (Brownell et al.
2001). Right whales were also seen near Chichi-jima Island (Bonin
Islands), Japan, in the 1990s (Mori et al. 1998). During 1994-2014,
right whale sightings were reported off northern Japan, the Kuril
Islands, and Kamchatka during April through August, with highest
densities in May and August (Matsuoka et al. 2015). All sightings were
north of 38[deg] N, and in July-August, the main distribution was north
of 42[deg] N (Matsuoka et al. 2015). Right whale sightings were made
within the Emperor Seamounts survey area during August, and adjacent to
the survey area during May and July (Matsuoka et al. 2015). Ovsyanikova
et al. (2015) also reported right whale sightings in the western
Pacific Ocean during 1977-2014; although they also reported sightings
off eastern Japan, the Kuril Islands, and southeast Kamchatka,
including sightings to the west of the proposed Emperor Seamounts
survey area, no sightings were reported within the proposed survey
area. Sekiguchi et al. (2014) reported several sightings just to the
north and west of the proposed survey area during June 2012.
Although there are a few historical records of North Pacific right
whales in Hawaiian waters (Brownell et al. 2001), they are very
unlikely to occur in the Hawaiian survey area, especially during the
summer. However, right whales could be encountered in the Emperor
Seamounts survey area during spring and summer, and likely fall.
Individuals that could occur there would likely be from a western North
Pacific stock rather than the eastern North Pacific stock.
Humpback Whale
The humpback whale is found throughout all oceans of the World
(Clapham 2009), with recent genetic evidence suggesting three separate
subspecies: North Pacific, North Atlantic, and Southern Hemisphere
(Jackson et al. 2014). Nonetheless, genetic analyses suggest some gene
flow (either past or present) between the North and South Pacific
(e.g., Jackson et al. 2014; Bettridge et al. 2015). Although considered
to be mainly a coastal species, the humpback whale often traverses deep
pelagic areas while migrating (e.g., Mate et al. 1999; Garrigue et al.
2015).
North Pacific humpback whales migrate between summer feeding
grounds along the Pacific Rim and the Bering and Okhotsk seas, and
winter calving and breeding areas in subtropical and tropical waters
(Pike and MacAskie 1969; Rice 1978; Winn and Reichley 1985;
Calambokidis et al. 2000, 2001, 2008). In the North Pacific, humpbacks
winter in four different breeding areas: (1) Along the coast of Mexico;
(2) along the coast of Central America; (3) around the Main Hawaiian
Islands; and (4) in the western Pacific, particularly around the
Ogasawara and Ryukyu islands in southern Japan and the northern
Philippines (Calambokidis et al. 2008; Fleming and Jackson 2011;
Bettridge et al. 2015).
Humpback whales were listed as endangered under the Endangered
Species Conservation Act (ESCA) in June 1970. In 1973, the ESA replaced
the ESCA, and humpbacks continued to be listed as endangered. NMFS
recently evaluated the status of the species, and on September 8, 2016,
NMFS divided the species into 14 distinct population segments (DPS),
removed the current species-level listing, and in its place listed four
DPSs as endangered and one DPS as threatened (81 FR 62259, September 8,
2016). The remaining nine DPSs were not listed. There are two DPSs that
occur in the action area: The Hawaii DPS, which is not listed under the
ESA (81 FR 62259) and the Western North Pacific DPS which is listed as
endangered.
The proposed seismic activity for the Emperor Seamount survey would
take place in late spring or early summer 2019. Humpbacks were reported
within the proposed action area in May, July, and August (Matsuoka et
al. 2015). Based on the timing of the action, it is likely that
humpback whales from the Western North Pacific DPS would be migrating
north through the action area to the feeding grounds, and thus be
exposed to the action. Hawaii DPS and Mexico DPS humpbacks would also
be migrating north at that time of year, but due to the location of the
breeding areas of these DPSs, we do not expect their migratory path to
take them through the action area.
There is potential for the mixing of the western and eastern North
Pacific humpback populations, as several individuals have been seen in
the wintering areas of Japan and Hawaii in separate years (Darling and
Cerchio 1993; Salden et al. 1999; Calambokidis et al. 2001, 2008).
Whales from these wintering areas have been shown to travel to summer
feeding areas in British Columbia, Canada, and Kodiak Island, Alaska
(Darling et al. 1996;
[[Page 30486]]
Calambokidis et al. 2001), but feeding areas in Russian waters may be
most important (Calambokidis et al. 2008). There appears to be a very
low level of interchange between wintering and feeding areas in Asia
and those in the eastern and central Pacific (Calambokidis et al. 2008;
Baker et al. 2013).
Humpbacks use Hawaiian waters for breeding from December to April;
peak abundance occurs from late-February to early-April (Mobley et al.
2001). Most humpbacks have been sighted there in water depths <180 m
(Fleming and Jackson 2011), but Frankel et al. (1995) detected singers
up to 13 km from shore at depths up to 550 m. During vessel-based line-
transect surveys in the Hawaiian Islands EEZ in July-December 2002, one
humpback whale was sighted on 21 November at ~20.3[deg] N, 154.9[deg] W
just north of the Island of Hawaii (Barlow et al. 2004). Another
sighting was made during summer-fall 2010 surveys, but the date and
location of that sighting were not reported (Bradford et al. 2017).
The Hawaiian Islands Humpback Whale National Marine Sanctuary
(HIHWNMS) was established in 1992 by the U.S. Congress to protect
humpback whales and their habitat in Hawaii (NOAA 2018a). The sanctuary
provides essential breeding, calving, and nursing areas necessary for
the long-term recovery of the North Pacific humpback whale population.
The HIHWNMS provides protection to humpbacks in the shallow waters
(from the shoreline to a depth of 100 fathoms or 183 m) around the four
islands area of Maui, Penguin Bank; off the north shore of Kauai, the
north and south shores of Oahu, and the north Kona and Koahal coast of
the island of Hawaii (NOAA 2018a). These areas, as well as some of the
waters surrounding them, are also considered breeding BIAs (Baird et
al. 2015). The proposed seismic lines are located at least 10 km from
the HIHWNMS (Fig. 1). However, humpback whales are not expected to be
encountered in the Hawaiian survey area during the summer.
During Japanese surveys in the western North Pacific from 1994-
2014, humpbacks were seen off northern Japan, the Kuril Islands, and
Kamchatka (Miyashita 2006; Matsuoka et al. 2015). Sightings were
reported for the months of April through September, with lowest
densities in April and September (Matsuoka et al. 2015). In May and
June, sightings were concentrated east of northern Japan between
37[deg] and 43[deg] N; concentrations moved north of 45[deg]N during
July and August, off the Kuril Islands and Kamchatka (Mutsuoka et al.
2015). Humpback whales were encountered within the proposed Emperor
Seamount study area in May, July, and August (Matsuoka et al. 2015).
Thus, humpbacks could be encountered in the Emperor Seamounts
survey area during spring and summer, as individuals are migrating to
northern feeding grounds at that time. They could also be encountered
in the survey area during fall, on their southbound migration. Humpback
whale occurrences in the Hawaii survey area during the time of the
proposed survey would be rare.
Bryde's Whale
Bryde's whale occurs in all tropical and warm temperate waters in
the Pacific, Atlantic, and Indian oceans, between 40[deg] N and 40[deg]
S (Kato and Perrin 2009). It is one of the least known large baleen
whales, and its taxonomy is still under debate (Kato and Perrin 2009).
B. brydei is commonly used to refer to the larger form or ``true''
Bryde's whale and B. edeni to the smaller form; however, some authors
apply the name B. edeni to both forms (Kato and Perrin 2009). Although
there is a pattern of movement toward the Equator in the winter and the
poles during the summer, Bryde's whale does not undergo long seasonal
migrations, remaining in warm ([gteqt]16[deg] C) water year-round (Kato
and Perrin 2009). Bryde's whales are known to occur in both shallow
coastal and deeper offshore waters (Jefferson et al. 2015).
In the Pacific United States, a Hawaii and an Eastern Tropical
Pacific stock are recognized (Carretta et al. 2017). In Hawaii, Bryde's
whales are typically seen offshore (e.g., Barlow et al. 2004; Barlow
2006), but Hopkins et al. (2009) reported a Bryde's whale within 70 km
of the Main Hawaiian Islands. During summer-fall surveys of the
Hawaiian Islands EEZ, 13 sightings were made in 2002 (Barlow 2006), and
32 sightings were reported during 2010 (Bradford et al. 2017). Bryde's
whales were primarily sighted in the western half of the Hawaiian
Islands EEZ, with the majority of sightings associated with the
Northwestern Hawaiian Islands; none was made in the proposed survey
area (Barlow et al. 2004; Barlow 2006; Bradford et al. 2013; Forney et
al. 2015; Carretta et al. 2017).
Bryde's whales have been regularly seen during Japanese summer
sighting surveys in the western North Pacific, south of 43[deg] S
(Hakamada et al. 2009, 2017), and individual movements have been
tracked with satellite tags in offshore waters off Japan (Murase et al.
2016). No recent sightings have been made in the proposed Emperor
Seamounts survey area, but commercial catches have been reported there
(IWC 2007a).
Limited numbers of Bryde's whale could occur in the Emperor
Seamounts survey area, but its distributional range is generally to the
south of this region. However, it could occur in the Hawaiian survey
area at any time of the year.
Common Minke Whale
The common minke whale has a cosmopolitan distribution ranging from
the tropics and subtropics to the ice edge in both hemispheres
(Jefferson et al. 2015). In the Northern Hemisphere, minke whales are
usually seen in coastal areas, but can also be seen in pelagic waters
during northward migrations in spring and summer, and southward
migration in autumn (Stewart and Leatherwood 1985). In the North
Pacific, the summer range extends to the Chukchi Sea; in the winter,
minke whales move further south to within 2[deg] of the Equator (Perrin
and Brownell 2009). The International Whaling Commission (IWC)
recognizes three stocks in the North Pacific: The Sea of Japan/East
China Sea, the rest of the western Pacific west of 180[deg] N, and the
remainder of the Pacific (Donovan 1991).
In U.S. Pacific waters, three stocks are recognized: Alaska,
Hawaii, and California/Oregon/Washington stocks (Carretta et al. 2017).
In Hawaii, the minke whale is thought to occur seasonally from November
through March (Rankin and Barlow 2005). It is generally believed to be
uncommon in Hawaiian waters; however, several studies using acoustic
detections suggest that minke whales may be more common than previously
thought (Rankin et al. 2007; Oswald et al. 2011). Acoustic detections
have been recorded around the Hawaiian Islands during fall-spring
surveys in 1997 and 2000-2006 (Rankin and Barlow 2005; Barlow et al.
2008; Rankin et al. 2008), and from seafloor hydrophones positioned ~50
km from the coast of Kauai during February-April 2006. Similarly,
passive acoustic detections of minke whales have been recorded at the
ALOHA station (22.75[deg] N, 158[deg] W) from October-May for decades
(Oswald et al. 2011).
A lack of sightings is likely related to misidentification or low
detection capability in poor sighting conditions (Rankin et al. 2007).
Two minke whale sightings were made west of 167[deg] W, one in November
2002 and one in October 2010, during surveys of the Hawaiian Islands
EEZ (Barlow et al. 2004; Bradford et al. 2013; Carretta et al. 2017).
Numerous additional sightings in
[[Page 30487]]
the EEZ were made by observers on Hawaii-based longline fishing
vessels, including four near the proposed survey area to the north and
south of the Main Hawaiian Islands (Carretta et al. 2017).
Minke whales have been seen regularly during Japanese sighting
surveys in the western North Pacific during summer (Miyashita 2006;
Hakamada et al. 2009), and one sighting was made in August 2010 in
offshore waters off Japan during the Shatsky Rise cruise (Holst and
Beland 2010). Minke whales were sighted within the Emperor Seamounts
survey area in the greatest numbers in August, with the lowest numbers
occurring during May and June (Hakamada et al. 2009).
Thus, minke whales could be encountered in the Emperor Seamounts
survey area during spring and summer, and likely fall, and could occur
in limited numbers in the Hawaiian survey area during the summer.
Sei Whale
The sei whale occurs in all ocean basins (Horwood 2009), but
appears to prefer mid-latitude temperate waters (Jefferson et al.
2015). It undertakes seasonal migrations to feed in subpolar latitudes
during summer and returns to lower latitudes during winter to calve
(Horwood 2009). The sei whale is pelagic and generally not found in
coastal waters (Harwood and Wilson 2001). It occurs in deeper waters
characteristic of the continental shelf edge region (Hain et al. 1985)
and in other regions of steep bathymetric relief such as seamounts and
canyons (Kenney and Winn 1987; Gregr and Trites 2001).
During summer in the North Pacific, the sei whale can be found from
the Bering Sea to the Gulf of Alaska and down to southern California,
as well as in the western Pacific from Japan to Korea. In the U.S.
Pacific, an Eastern North Pacific and a Hawaii stock are recognized
(Carretta et al. 2017). In Hawaii, the occurrence of sei whales is
considered rare (DoN 2005). However, six sightings were made during
surveys in the Hawaiian Islands EEZ in July-December 2002 (Barlow
2006), including several along the north coasts of the Main Hawaiian
Islands (Barlow et al. 2004). All sightings occurred in November, with
one sighting reported near proposed seismic Line 3 north of Hawaii
Island (Barlow et al. 2004). Bradford et al. (2017) reported two
sightings in the northwestern portion of the Hawaiian Islands EEZ
during summer-fall surveys in 2010. Hopkins et al. (2009) sighted one
group of three subadult sei whales northeast of Oahu in November 2007.
Sei whale vocalizations were also detected near Hawaii during November
2002 (Rankin and Barlow 2007). Breeding and calving areas for this
species in the Pacific are unknown, but those sightings suggest that
Hawaii may be an important reproductive area (Hopkins et al. 2009).
Sei whales have been regularly seen during Japanese surveys during
the summer in the western North Pacific (Miyashita 2006; Hakamada et
al. 2009; Sasaki et al. 2013). Sei whales have been sighted in and near
the Emperor Seamounts survey area, with the greatest numbers reported
for July and August; few sightings were made during May and June
(Hakamada et al. 2009).
Thus, sei whales could be encountered in both the Emperor Seamounts
and Hawaii survey areas during spring and summer.
Fin Whale
The fin whale is widely distributed in all the World's oceans
(Gambell 1985), although it is most abundant in temperate and cold
waters (Aguilar 2009). Nonetheless, its overall range and distribution
are not well known (Jefferson et al. 2015). A recent review of fin
whale distribution in the North Pacific noted the lack of sightings
across the pelagic waters between eastern and western winter areas
(Mizroch et al. 2009). The fin whale most commonly occurs offshore, but
can also be found in coastal areas (Aguilar 2009). Most populations
migrate seasonally between temperate waters where mating and calving
occur in winter, and polar waters where feeding occurs in summer
(Aguilar 2009). However, recent evidence suggests that some animals may
remain at high latitudes in winter or low latitudes in summer (Edwards
et al. 2015).
The fin whale is known to use the shelf edge as a migration route
(Evans 1987). Sergeant (1977) suggested that fin whales tend to follow
steep slope contours, either because they detect them readily, or
because the contours are areas of high biological productivity.
However, fin whale movements have been reported to be complex
(Jefferson et al. 2015). Stafford et al. (2009) noted that sea-surface
temperature is a good predictor variable for fin whale call detections
in the North Pacific.
North Pacific fin whales summer from the Chukchi Sea to California
and winter from California southwards (Gambell 1985). In the U.S.,
three stocks are recognized in the North Pacific: California/Oregon/
Washington, Hawaii, and Alaska (Northeast Pacific) (Carretta et al.
2017). Information about the seasonal distribution of fin whales in the
North Pacific has been obtained from the detection of fin whale calls
by bottom-mounted, offshore hydrophone arrays along the U.S. Pacific
coast, in the central North Pacific, and in the western Aleutian
Islands (Moore et al. 1998, 2006; Watkins et al. 2000a,b; Stafford et
al. 2007, 2009). Fin whale calls are recorded in the North Pacific
year-round, including near the Emperor Seamounts survey area (e.g.,
Moore et al. 2006; Stafford et al. 2007, 2009; Edwards et al. 2015). In
the central North Pacific, call rates peak during fall and winter
(Moore et al. 1998, 2006; Watkins et al. 2000a,b).
Sightings of fin whales have been made in Hawaiian waters during
fall and winter (Edwards et al. 2015), but fin whales are generally
considered uncommon at that time (DoN 2005). During spring and summer,
their occurrence in Hawaii is considered rare (DoN 2005; see Edwards et
al. 2015). There were five sightings of fin whales during summer-fall
surveys in 2002, with sightings during every month except August
(Barlow et al. 2004). Most sightings were made to the northwest of the
Main Hawaiian Islands; one sighting was made during October southeast
of Oahu (Barlow et al. 2004). Two sightings were made in the
Northwestern Hawaiian Islands during summer-fall 2010 (Carretta et al.
2017; Bradford et al. 2017). Two additional sightings in the EEZ were
made by observers on Hawaii-based longline fishing vessels, including
one near proposed seismic Line 3 north of Maui (Carretta et al. 2017).
Fin whale vocalizations have also been detected in Hawaiian waters,
mainly during winter (Oleson et al. 2014, 2016).
In the western Pacific, fin whales are seen off northern Japan, the
Kuril Islands, and Kamchatka during the summer (Miyashita 2006;
Matsuoka et al. 2015). During Japanese sightings surveys in the western
North Pacific from 1994-2014, the fin whale was sighted more frequently
than the blue, humpback, or right whale (Matsuoka et al. 2015). During
May-June, main distribution areas occurred from 35-40[deg] N and moved
north of 40[deg] N during July and August; high densities were reported
north of 45[deg] N (Matsuoka et al. 2015). During these surveys, fin
whales were seen in the proposed Emperor Seamounts survey area from May
through September, with most sightings during August (Matsuoka et al.
2015). Summer sightings in the survey area during 1958-2000 were also
reported by Mizroch et al. (2009) and during July-September 2005
(Miyashita 2006). Edwards et al. (2015) reported fin whale sightings
within or near the Emperor
[[Page 30488]]
Seamounts survey area from spring through fall.
Thus, fin whales could be encountered in the Emperor Seamounts
survey area from spring through fall, and could occur in the Hawaiian
survey area during summer in limited numbers.
Blue Whale
The blue whale has a cosmopolitan distribution and tends to be
pelagic, only coming nearshore to feed and possibly to breed (Jefferson
et al. 2015). Blue whale migration is less well defined than for some
other rorquals, and their movements tend to be more closely linked to
areas of high primary productivity, and hence prey, to meet their high
energetic demands (Branch et al. 2007). Generally, blue whales are
seasonal migrants between high latitudes in the summer, where they
feed, and low latitudes in the winter, where they mate and give birth
(Lockyer and Brown 1981). Some individuals may stay in low or high
latitudes throughout the year (Reilly and Thayer 1990; Watkins et al.
2000b).
In the North Pacific, blue whale calls are detected year-round
(Stafford et al. 2001, 2009; Moore et al. 2002, 2006; Monnahan et al.
2014). Stafford et al. (2009) reported that sea-surface temperature is
a good predictor variable for blue whale call detections in the North
Pacific. Although it has been suggested that there are at least five
subpopulations in the North Pacific (Reeves et al. 1998), analysis of
calls monitored from the U.S. Navy Sound Surveillance System (SOSUS)
and other offshore hydrophones (e.g., Stafford et al. 1999, 2001, 2007;
Watkins et al. 2000a; Stafford 2003) suggests that there are two
separate populations: One in the eastern and one in the central North
Pacific (Carretta et al. 2017). The Eastern North Pacific Stock
includes whales that feed primarily off California from June-November
and winter off Central America (Calambokidis et al. 1990; Mate et al.
1999). The Central North Pacific Stock feeds off Kamchatka, south of
the Aleutians and in the Gulf of Alaska during summer (Stafford 2003;
Watkins et al. 2000b), and migrates to the western and central Pacific
(including Hawaii) to breed in winter (Stafford et al. 2001; Carretta
et al. 2017). The status of these two populations could differ
substantially, as little is known about the population size in the
western North Pacific (Branch et al. 2016).
Blue whales are considered rare in Hawaii (DoN 2005). However, call
types from both stocks have been recorded near Hawaii during August-
April, although eastern calls were more prevalent; western calls were
mainly detected during December-March, whereas eastern calls peaked
during August and September and were rarely heard during October-March
(Stafford et al. 2001). No sightings were made in the Hawaiian Islands
EEZ during surveys in July-December 2002 (Barlow et al. 2004; Barlow
2006). One sighting was made in the Northwestern Hawaiian Islands
during August-October 2010 (Bradford et al. 2013). Three additional
sightings in the EEZ were made by observers on Hawaii-based longline
fishing vessels during 1994-2009, including one in offshore waters
north of Maui (Carretta et al. 2017).
In the western North Pacific, blue whale calls have been detected
throughout the year, but are more prevalent from July-December
(Stafford et al. 2001). Numerous blue whale sightings have also been
made in the western North Pacific during Japanese surveys during 1994-
2014 (Miyashita 2006; Matsuoka et al. 2015). A northward migration
pattern was evident, with the main distribution occurring from 35-
40[deg] N during May and June, and north of 40[deg] N during July and
August (Matsuoka et al. 2015). High densities were reported north of
45[deg] N (Matsuoka et al. 2015). Blue whales were seen in the proposed
Emperor Seamounts survey area during August and September and adjacent
to the area during May and July (Matsuoka et al. 2015).
Thus, blue whales could be encountered in the Emperor Seamounts and
Hawaii survey areas at any time of the year, but are more likely to
occur in the Emperor Seamounts area during summer, and in the Hawaii
survey area during winter.
Sperm Whale
The sperm whale is the largest of the toothed whales, with an
extensive worldwide distribution from the edge of the polar pack ice to
the Equator (Whitehead 2009). Sperm whale distribution is linked to its
social structure: Mixed groups of adult females and juveniles of both
sexes generally occur in tropical and subtropical waters at latitudes
less than ~40[deg] (Whitehead 2009). After leaving their female
relatives, males gradually move to higher latitudes with the largest
males occurring at the highest latitudes and only returning to tropical
and subtropical regions to breed. Sperm whales generally are
distributed over large areas that have high secondary productivity and
steep underwater topography, in waters at least 1000 m deep (Jaquet and
Whitehead 1996). They are often found far from shore, but can be found
closer to oceanic islands that rise steeply from deep ocean waters
(Whitehead 2009).
Sperm whale vocalizations have been recorded throughout the Central
and Western Pacific Ocean (Merkens et al. 2016). Sperm whales are
widely distributed in Hawaiian waters throughout the year (Mobley et
al. 2000) and are considered a separate stock from the Oregon/
Washington/California stock in U.S. waters (Carretta et al. 2017).
Higher densities occur in deep, offshore waters (Forney et al. 2015).
During summer-fall surveys of the Hawaiian Islands EEZ, 43 sightings
were made in 2002 (Barlow 2006) and 41 were made in 2010 (Bradford et
al. 2013). Sightings were widely distributed across the EEZ during both
surveys; numerous sightings occurred in and near the proposed survey
area (Barlow et al. 2004; Barlow 2006; Bradford et al. 2017). All
sightings during surveys of the Main Hawaiian Islands in 2000-2012 were
made in water >1000 m in depth, with most sightings in areas >3000 m
deep (Baird et al. 2013). Sightings were made during surveys of the
Island of Hawaii during all seasons, including near proposed seismic
Line 1; no sightings were made off Oahu (Baird et al. 2013). Sperm
whales were also detected acoustically off the west coast of the Hawaii
Island year-round (Klinck et al. 2012; Giorli et al. 2016).
Sperm whales have been regularly seen in the western North Pacific
during Japanese surveys during summer (Miyashita 2006; Hakamada et al.
2009), and sightings were also made in offshore waters east of Japan
and on the Shatsky Rise during a summer survey in 2010 (Holst and
Beland 2010). During winter, few sperm whales are observed off the east
coast of Japan (Kato and Miyashita 1998). Sperm whales have been
sighted in and near the Emperor Seamounts survey area from May through
August, with the greatest numbers occurring there during June-August
(Miyashita 2006; Hakamada et al. 2009).
Thus, sperm whales could be encountered in the Emperor Seamounts
and Hawaii survey areas at any time of the year.
Pygmy and Dwarf Sperm Whales
The pygmy and dwarf sperm whales are distributed widely throughout
tropical and temperate seas, but their precise distributions are
unknown because much of what we know of the species comes from
strandings (McAlpine 2009). It has been suggested that the pygmy sperm
whale is more temperate and the dwarf sperm whale
[[Page 30489]]
more tropical, based at least partially on live sightings at sea from a
large database from the Eastern Tropical Pacific or ETP (Wade and
Gerrodette 1993). Kogia spp. are difficult to sight at sea, because of
their dive behavior and perhaps because of their avoidance reactions to
ships and behavior changes in relation to survey aircraft (W[uuml]rsig
et al. 1998). Although there are few useful estimates of abundance for
pygmy or dwarf sperm whales anywhere in their range, they are thought
to be fairly common in some areas.
Both Kogia species are sighted primarily along the continental
shelf edge and slope and over deeper waters off the shelf (Hansen et
al. 1994; Davis et al. 1998; Jefferson et al. 2015). However, several
studies have suggested that pygmy sperm whales live mostly beyond the
continental shelf edge, whereas dwarf sperm whales tend to occur closer
to shore, often over the continental shelf (Rice 1998; Wang et al.
2002; MacLeod et al. 2004). On the other hand, McAlpine (2009) and
Barros et al. (1998) suggested that dwarf sperm whales could be more
pelagic and dive deeper than pygmy sperm whales.
Vocalizations of Kogia spp. have been recorded in the North Pacific
Ocean (Merkens et al. 2016). An insular resident population of dwarf
sperm whales occurs within ~20 km from the Main Hawaiian Islands
throughout the year (Baird et al. 2013; Oleson et al. 2013). During
small-boat surveys in 2000-2012, dwarf sperm whales were sighted in all
water depth categories up to 5000 m deep, but the highest sighting
rates were in water 500-1,000 m deep (Baird et al. 2013). Of a total of
74 sightings during those surveys, most sightings were made off the
Island of Hawaii, including near proposed seismic Line 1 (Baird et al.
2013). The area off the west coast of the Island of Hawaii is
considered a BIA for dwarf sperm whales (Baird et al. 2015). Only one
sighting was made off Oahu (Baird et al. 2013).
Only five sightings of pygmy sperm whales were made during the
surveys, including several off the west coast of the Island of Hawaii;
the majority of sightings were made in water >3,000 m deep (Baird et
al. 2013). The dwarf sperm whale was one of the most abundant species
during a summer-fall survey of the Hawaiian EEZ in 2002 (Barlow 2006);
during that survey, two sightings of pygmy sperm whales, five sightings
of dwarf sperm whales, and one sighting of an unidentified Kogia sp.
were made. All sightings were made in the western portion of the EEZ
(Barlow et al. 2004; Barlow 2006). During summer-fall surveys of the
Hawaiian EEZ in 2010, one dwarf sperm whale and one unidentified Kogia
sp. were sighted (Bradford et al. 2017); no sightings were made in or
near the proposed survey area (Carretta et al. 2017).
Although Kogia spp. have been seen during Japanese sighting surveys
in the western North Pacific in August-September (Kato et al. 2005), to
the best of our knowledge, there are no direct data available for the
Emperor Seamounts survey area with respect to Kogia spp. It is possible
that Kogia spp could occur at both survey locations is limited numbers.
Cuvier's Beaked Whale
Cuvier's beaked whale is the most widespread of the beaked whales,
occurring in almost all temperate, subtropical, and tropical waters and
even some sub-polar and polar waters (MacLeod et al. 2006). It is
likely the most abundant of all beaked whales (Heyning and Mead 2009).
Cuvier's beaked whale is found in deep water over and near the
continental slope (Jefferson et al. 2015).
Cuvier's beaked whale has been sighted during surveys in Hawaii
(Barlow 2006; Baird et al. 2013; Bradford et al. 2017). Resighting and
telemetry data suggest that a resident insular population of Cuvier's
beaked whale may exist in Hawaii, distinct from offshore, pelagic
whales (e.g. McSweeney et al. 2007; Baird et al. 2013; Oleson et al.
2013). During small-boat surveys around the Hawaiian Islands in 2000-
2012, sightings were made in water depths of 500-4,000 m off the west
coast of the Island of Hawaii during all seasons (Baird et al. 2013).
The waters around the Island of Hawaii are considered a BIA for
Cuvier's beaked whale (Baird et al. 2015); proposed seismic Line 1
would traverse this area.
During summer-fall surveys of the Hawaiian Islands EEZ, three
sightings of Cuvier's beaked whale were made in the western portion of
the EEZ in 2002 (Barlow 2006) and 23 were made in the EEZ in 2010
(Bradford et al. 2013). It was one of the most abundant cetacean
species sighted in 2002 (Barlow 2006). In 2010, most sightings were
made in nearshore waters of the Northwestern Hawaiian Islands, but one
was made on the west coast of the Island of Hawaii, and another was
made far offshore and to the southwest of Kauai (Carretta et al. 2017).
Cuvier's beaked whales were also reported near proposed seismic line 1
during November 2009 (Klinck et al. 2012). They have also been detected
acoustically at hydrophones deployed near the Main Hawaiian Islands
during spring and fall (Baumann-Pickering et al. 2014, 2016), including
off the west coast of the Island of Hawaii (Klinck et al. 2012).
Probable acoustic detections were also made at Cross Seamount, south of
the Main Hawaiian Islands, at 18.72[deg] N, 158.25[deg] W (Johnston
2008).
Cuvier's beaked whale has been seen during Japanese sighting
surveys in August-September in the western North Pacific (Kato et al.
2005). It has also been detected acoustically in the Aleutian Islands
(Baumann-Pickering et al. 2014). There is very little information on
this species for the Emperor Seamounts survey area, but what is known
of its distribution and habitat preferences suggests that it could
occur there. Therefore, Cuvier's beaked whales could occur at both
survey locations.
Longman's Beaked Whale
Longman's beaked whale, also known Indo-Pacific beaked whale, used
to be one of the least known cetacean species, but it is now one of the
more frequently sighted beaked whales (Pitman 2009a). Longman's beaked
whale occurs in tropical waters throughout the Indo-Pacific, with
records from 30[deg] S to 40[deg] N (Pitman 2009a). Longman's beaked
whale is most often sighted in waters with temperatures >=26[deg]C and
depth >2,000 m, and sightings have also been reported along the
continental slope (Anderson et al. 2006; Pitman 2009a).
During small-boat surveys around the Hawaiian Islands in 2000-2012,
a single sighting of Longman's beaked whale was made off the west coast
of the Island of Hawaii during summer (Baird et al. 2013). During
summer-fall surveys of the Hawaiian Islands EEZ, one sighting was made
in 2002 and three were made in 2010; one sighting was made in offshore
waters southwest of Ohau, and another was made at the edge of the EEZ
southwest of the Island of Hawaii (Barlow et al. 2004; Barlow 2006;
Bradford et al. 2013). Acoustic detections have been made at the
Palmyra Atoll and the Pearl and Hermes Reef (Baumann-Pickering et al.
2014).
Longman's beaked whale has been seen during Japanese sighting
surveys in August-September in the western North Pacific (Kato et al.
2005). However, what is known about its distribution and habitat
preferences suggests that it does not occur in the Emperor Seamounts
survey area.
Blainville's Beaked Whale
Blainville's beaked whale is found in tropical and warm temperate
waters of all oceans (Pitman 2009b). It has the widest distribution
throughout the world of all mesoplodont species and appears to be
common (Pitman 2009b).
[[Page 30490]]
It is commonly sighted in some areas of Hawaii (Jefferson et al. 2015).
McSweeney et al. (2007), Schorr et al. (2009), Baird et al. (2013),
and Oleson et al. (2013) have suggested the existence of separate
insular and offshore Blainville's beaked whales in Hawaiian waters.
During small-boat surveys around the Hawaiian Islands in 2000-2012,
sightings were made in shelf as well as deep water, with the highest
sighting rates in water 3500-4000 m deep, followed by water 500-1000 m
deep (Baird et al. 2013). Sightings were made during all seasons off
the island of Hawaii, as well as off Oahu (Baird et al. 2013). The area
off the west coast of Hawaii Island is considered a BIA for
Blainville's beaked whale (Baird et al. 2015); proposed seismic Line 1
would traverse this BIA. During summer-fall shipboard surveys of the
Hawaiian Islands EEZ, three sightings were made in 2002 and two were
made in 2010, all in the western portion of the EEZ (Barlow et al.
2004; Barlow 2006; Bradford et al. 2013). In addition, there were four
sightings of unidentified Mesoplodon there in 2002 (Barlow et al. 2004;
Barlow 2006) and 10 in 2010 (Bradford et al. 2013).
Blainville's beaked whales have also been detected acoustically at
hydrophones deployed near the Main Hawaiian Islands throughout the year
(Baumann-Pickering et al. 2014, 2016; Henderson et al. 2016; Manzano-
Roth et al. 2016), including off the west coast of the Island of
Hawaii, near proposed seismic Line 1, during October-November 2009
(Klinck et al. 2012). Probable acoustic detections were also made at
Cross Seamount, south of the Main Hawaiian Islands, at 18.72[deg] N,
158.25[deg] W (Johnston 2008). Blainville's beaked whale is expected to
be absent from the Emperor Seamounts survey area.
Stejneger's Beaked Whale
Stejneger's beaked whale occurs in subarctic and cool temperate
waters of the North Pacific (Mead 1989). Most records are from Alaskan
waters, and the Aleutian Islands appear to be its center of
distribution (Mead 1989). In the western Pacific Ocean, Stejneger's
beaked whale has been seen during Japanese sighting surveys during
August-September (Kato et al. 2005). Seasonal peaks in strandings along
the western coast of Japan suggest that this species may migrate north
in the summer from the Sea of Japan (Mead 1989). They have also been
detected acoustically in the Aleutian Islands during summer, fall, and
winter (Baumann-Pickering et al. 2014).
Given its distributional range (see Jefferson et al. 2015),
Stejneger's beaked whale could occur in the Emperor Seamounts survey
area. It does not occur in the Hawaiian survey area.
Ginkgo-Toothed Beaked Whale
Ginkgo-toothed beaked whale is only known from stranding and
capture records (Mead 1989; Jefferson et al. 2015). It is hypothesized
to occupy tropical and warm temperate waters of the Indian and Pacific
oceans (Pitman 2009b). Its distributional range in the North Pacific
extends from Japan to the Galapagos Islands, and there are also records
for the South Pacific as far south as Australia and New Zealand
(Jefferson et al. 2015). Although its distributional range is thought
to be south of Hawaii (Jefferson et al. 2015), vocalizations likely
from this species have been detected acoustically at hydrophones
deployed near the Main Hawaiian Islands and just to the south at Cross
Seamount (18.72[deg] N, 158.25[deg] W), as well as at the Wake Atoll
and Mariana Islands (Baumann-Pickering et al. 2014, 2016). However, no
sightings have been made in Hawaiian waters (Barlow 2006; Baird et al.
2013; Bradford et al. 2017).
The ginkgo-toothed beaked whale could occur in the southern parts
of the Hawaiian survey area, but it is not expected to occur in the
Emperor Seamounts survey area.
Deraniyagala's Beaked Whale
Deraniyagala's beaked whale is a newly recognized species of whale
that recently has been described for the tropical Indo-Pacific, where
it is thought to occur between ~15[deg] N and ~10[deg] S (Dalebout et
al. 2014). Strandings have been reported for the Maldives, Sri Lanka,
the Seychelles, Kiribati, and Palmyra Atoll (Dalebout et al. 2014), and
acoustic detections have been made at Palmyra Atoll and Kingman Reef in
the Line Islands (Baumann-Pickering et al. 2014). It is closely related
to ginkgo-toothed beaked whale, but DNA and morphological data have
shown that the two are separate species (Dalebout et al. 2014).
Although possible, Deraniyagala's beaked whale is unlikely to occur
in the Hawaiian survey area, and its range does not include the Emperor
Seamounts survey area.
Hubb's Beaked Whale
Hubb's beaked whale occurs in temperate waters of the North Pacific
(Mead 1989). Most of the stranding records are from California (Willis
and Baird 1998). Its distribution appears to be correlated with the
deep subarctic current (Mead et al. 1982). Its range is believed to be
continuous across the North Pacific (Macleod et al. 2006), although
this has yet to be substantiated because very few direct at-sea
observations exist.
Hubb's beaked whale was seen during Japanese sighting surveys in
the western North Pacific during August-September (Kato et al. 2005).
However, there is very little information on this species for the
Emperor Seamounts survey area, but what is known of its distribution
suggests it would occur in limited numbers. The Hubb's beaked whale is
unlikely to occur in the Hawaiian survey area.
Baird's Beaked Whale
Baird's beaked whale has a fairly extensive range across the North
Pacific north of 30[deg] N, and strandings have occurred as far north
as the Pribilof Islands (Rice 1986). Two forms of Baird's beaked whales
have been recognized--the common slate-gray form and a smaller, rare
black form (Morin et al. 2017). The gray form is seen off Japan, in the
Aleutians, and on the west coast of North America, whereas the black
from has been reported for northern Japan and the Aleutians (Morin et
al. 2017). Recent genetic studies suggest that the black form could be
a separate species (Morin et al. 2017).
Baird's beaked whale is currently divided into three distinct
stocks: Sea of Japan, Okhotsk Sea, and Bering Sea/eastern North Pacific
(Balcomb 1989; Reyes 1991). The whales occur year-round in the Okhotsk
Sea and Sea of Japan (Kasuya 2009). Baird's beaked whales sometimes are
seen close to shore, but their primary habitat is over or near the
continental slope and oceanic seamounts in waters 1,000-3,000 m deep
(Jefferson et al. 1993; Kasuya and Ohsumi 1984; Kasuya 2009).
Off Japan's Pacific coast, Baird's beaked whales start to appear in
May, numbers increase over the summer, and decrease toward October
(Kasuya 2009). During this time, they are nearly absent in offshore
waters (Kasuya 2009). Kato et al. (2005) also reported the presence of
Baird's beaked whales in the western North Pacific in August-September.
They have also been detected acoustically in the Aleutian Islands
(Baumann-Pickering et al. 2014).
Baird's beaked whale could be encountered at the Emperor Seamounts
survey area, but its distribution does not include Hawaiian waters.
Rough-Toothed Dolphin
The rough-toothed dolphin is distributed worldwide in tropical to
[[Page 30491]]
warm temperate oceanic waters (Miyazaki and Perrin 1994; Jefferson
2009). In the Pacific, it occurs from central Japan and northern
Australia to Baja California, Mexico, and southern Peru (Jefferson
2009). It generally occurs in deep, oceanic waters, but can be found in
shallower coastal waters in some regions (Jefferson et al. 2015).
The rough-toothed dolphin is expected to be one of the most
abundant cetaceans in the Hawaiian survey area, based on previous
surveys in the area (Barlow et al. 2004; Barlow 2006; Baird et al.
2013; Bradford et al. 2017). Higher densities are expected to occur in
deeper waters around the Hawaiian Islands than in far offshore waters
of the Hawaiian EEZ (Forney et al. 2015). During small-boat surveys
around the Hawaiian Islands in 2000-2012, it was sighted in water as
deep as 5,000 m, with the highest sighting rates in water >3500 m deep,
throughout the year (Baird et al. 2013). Sightings were made off the
Island of Hawaii as well as Oahu (Baird et al. 2013). The area west of
the Island of Hawaii is considered BIA (Baird et al. 2015); proposed
seismic Line 1 would traverse this area. During summer-fall surveys of
the Hawaiian Islands EEZ, rough-toothed dolphins were observed
throughout the EEZ, including near the proposed survey area to the
north and south of the Main Hawaiian Islands; in total, there were 18
sightings in 2002 and 24 sightings in 2010 (Barlow 2006; Barlow et al.
2004; Bradford et al. 2017). Acoustic detections have also been made in
Hawaiian waters (Rankin et al. 2015).
In the western North Pacific Ocean, rough-toothed dolphins have
been seen during Japanese sighting surveys during August-September
(Kato et al. 2005). However, there is very little information on this
species for the Emperor Seamounts survey area, but what is known of its
distribution suggests that it is unlikely to occur there.
Common Bottlenose Dolphin
The bottlenose dolphin occurs in tropical, subtropical, and
temperate waters throughout the World (Wells and Scott 2009).
Generally, there are two distinct bottlenose dolphin ecotypes, one
mainly found in coastal waters and one mainly found in oceanic waters
(Duffield et al. 1983; Hoelzel et al. 1998; Walker et al. 1999). As
well as inhabiting different areas, these ecotypes differ in their
diving abilities (Klatsky 2004) and prey types (Mead and Potter 1995).
The bottlenose dolphin is expected to be one of the most abundant
cetaceans in the Hawaiian survey area, based on previous surveys in the
region (Barlow 2006; Baird et al. 2013; Bradford et al. 2017). Higher
densities are expected to occur around the Hawaiian Islands than in far
offshore waters of the Hawaiian EEZ (Forney et al. 2015). Photo-
identification studies have shown that there are distinct resident
populations at the four island groups in Hawaii (Kauai & Niihau, Oahu,
the 4-island region, and the Island of Hawaii); the 1,000-m isobath
serves as the boundary between these resident insular stocks and the
Hawaii pelagic stock (Martien et al. 2012). Note that the Kauai/Niihau
stock range does not occur near the proposed tracklines and will not be
discussed further. Additionally, 98.5 percent of the Hawaii survey will
take in deep (>1,000 m) water. The areas where the insular stocks are
found are also considered BIAs (Baird et al. 2015). Proposed seismic
Lines 1 and 2 would traverse the BIAS to the west of Oahu and west of
the Island of Hawaii.
During small-boat surveys around the Hawaiian Islands in 2000-2012,
the bottlenose dolphin was sighted in water as deep as 4,500 m, but the
highest sighting rates occurred in water <500 m deep (Baird et al.
2013). Sightings were made during all seasons off the Island of Hawaii,
including near proposed seismic Line 1, and off Oahu (Baird et al.
2013). Common bottlenose dolphins were also observed during summer-fall
surveys of the Hawaiian EEZ, mostly in nearshore waters but also in
offshore waters, including in and near the proposed survey area among
the Main Hawaiian Islands, and to the north and south of the islands
(see map in Carretta et al. 2017). Fifteen sightings were made in 2002
(Barlow 2006), and 19 sightings were made in 2010 (Bradford et al.
2017).
In the western North Pacific Ocean, common bottlenose dolphins have
been sighted off the east coast of Japan during summer surveys in 1983-
1991 (Miyashita 1993a). Although only part of the proposed Emperor
Seamounts survey area was surveyed during the month of August, no
sightings were made within or near the survey area (Miyashita 1993a).
Offshore sightings to the south of the proposed survey area were made
during September (Miyashita 1993a), and there is also a record just to
the southwest of the survey area during summer (Kanaji et al. 2017).
The distributional range of the common bottlenose dolphin does not
appear to extend north to the Emperor Seamounts survey area; thus, it
is not expected to be encountered during the survey.
Short-Beaked Common Dolphin
The common dolphin is found in tropical and warm temperate oceans
around the World (Perrin 2009a). It ranges as far south as 40[deg] S in
the Pacific Ocean, is common in coastal waters 200-300 m deep, and is
also associated with prominent underwater topography, such as seamounts
(Evans 1994). There are two species of common dolphins: The short-
beaked common dolphin (D. delphis) and the long-beaked common dolphin
(D. capensis). The short-beaked common dolphin is mainly found in
offshore waters, and the long-beaked common dolphin is more prominent
in coastal areas.
During Japanese sighting surveys in the western North Pacific in
August-September, both long- and short-beaked common dolphins have been
seen (Kato et al. 2005). Kanaji et al. (2017) reported one record to
the southwest of the proposed survey area during summer. There are also
bycatch records of short-beaked common dolphins near the Emperor
Seamounts survey area during summer and winter (Hobbs and Jones 1993).
Based on information regarding the distribution and habitat
preferences, only the short-beaked common dolphin could occur in the
region.
Both the the short-beaked and long-beaked common dolphin are not
expected to occur in the Hawaiian survey area as no sightings have been
made of either species during surveys of the Hawaii Islands (Barlow
2006; Baird et al. 2013; Bradford et al. 2017).
Pantropical Spotted Dolphin
The pantropical spotted dolphin is one of the most abundant
cetaceans and is distributed worldwide in tropical and some subtropical
waters (Perrin 2009b), between ~40[deg] N and 40[deg] S (Jefferson et
al. 2015). It is found primarily in deeper waters, but can also be
found in coastal, shelf, and slope waters (Perrin 2009b). There are two
forms of pantropical spotted dolphin: Coastal and offshore. The
offshore form inhabits tropical, equatorial, and southern subtropical
water masses; the pelagic individuals around the Hawaiian Islands
belong to a stock distinct from those in the ETP (Dizon et al. 1991;
Perrin 2009b). Spotted dolphins are commonly seen together with spinner
dolphins in mixed-species groups, e.g., in the ETP (Au and Perryman
1985), off Hawaii (Psarakos et al. 2003), and in the Marquesas
Archipelago (Gannier 2002).
The pantropical spotted dolphin is expected to be one of the most
abundant cetaceans in the proposed Hawaiian survey area based on
previous surveys in the region (Baird et al. 2013; Barlow 2006;
Bradford et al. 2017). Higher densities are expected to occur around
the Main Hawaiian Islands than elsewhere in the Hawaiian EEZ (Forney
[[Page 30492]]
et al. 2015). Sightings rates peak in depths from 1,500 to 3,500 m
(Baird et al. 2013). The Main Hawaiian Islands insular spotted dolphin
stock consists of two separate stocks at Oahu and 4-Islands (which
extend 20 km seaward), and one stock off the Island of Hawaii, up to 65
km from shore (Carretta et al. 2017). Spotted dolphins outside of these
insular stocks are part of the Hawaii pelagic stock (Carretta et al.
2017).
During small-boat surveys around the Hawaiian Islands in 2000-2012,
the pantropical spotted dolphin was sighted in all water depth
categories, with the lowest sighting rate in water <500 m (Baird et al.
2013). It was observed during all seasons, including off of Hawaii
Island and Oahu (Baird et al. 2013). It was also seen during summer-
fall surveys of the Hawaiian Islands EEZ including in the proposed
survey area, with sightings to the north, south, and around the Main
Hawaiian Islands (see map in Carretta et al. 2017); 14 sightings were
made in 2002 (Barlow 2006), and 12 sightings were made in 2010
(Bradford et al. 2017). The areas off southwest Oahu, south of Lanai,
and west of the Island of Hawaii are considered BIAs (Baird et al.
2015); proposed seismic Line 1 traverses the BIA west of the Island of
Hawaii. One sighting was made in July 2010 in the northwestern portion
of the Hawaiian EEZ during the Shatsky Rise cruise (Holst and Beland
2010).
In the western Pacific, pantropical spotted dolphins occur from
Japan south to Australia; they have been hunted in drive fisheries off
Japan for decades (Kasuya 2007). A sighting of three individuals was
made in offshore waters east of Japan in August 2010 during the Shatksy
Rise cruise (Holst and Beland 2010). Pantropical spotted dolphins were
also sighted off the east coast of Japan during summer surveys in 1983-
1991, with the highest densities in offshore waters between 30[deg] N
and 37[deg] N (Miyashita 1993a). Although only part of the proposed
Emperor Seamounts survey area was surveyed during the month of August,
no sightings were made within or near the survey area; offshore
sightings to the south of the proposed survey area were made during
August and September (Miyashita 1993a). The distributional range of the
pantropical spotted dolphin does not appear to extend north to the
Emperor Seamounts survey area; thus, it is not expected to be
encountered during the survey.
Spinner Dolphin
The spinner dolphin is pantropical in distribution, including
oceanic tropical and sub-tropical waters between 40[deg] N and 40[deg]
S (Jefferson et al. 2015). It is generally considered a pelagic species
(Perrin 2009b), but can also be found in coastal waters and around
oceanic islands (Rice 1998). In Hawaii, spinner dolphins belong to the
offshore stock (S.l. longirostris; Gray's spinner) that is separate
from animals in the ETP (Dizon et al. 1991).
The spinner dolphin is expected to be one of the most abundant
cetaceans in the Hawaiian survey area, based on previous surveys in the
region (Barlow 2006; Baird et al. 2013; Bradford et al. 2017). Higher
densities are expected to occur around in offshore waters south of the
Hawaiian Islands (Forney et al. 2015). There are six separate stocks
managed within the Hawaiian EEZ--the Hawaii Island, Oahu/4-islands,
Kauai/Niihau, Pearl & Hermes Reef, Midway Atoll/Kure, and Hawaiian
pelagic stocks (Carretta et al. 2017); individuals from three of these
stocks (Hawaii pelagic, Hawaii Island, Oahu/4-Islands) are expected to
overlap with the proposed survey area. The boundaries of these stocks
are out to 10 n.mi. from shore; these regions are also considered BIAs
(Baird et al. 2015). Proposed seismic Line 1 traverses the BIA west of
the Island of Hawaii.
During small-boat surveys around the Hawaiian Islands in 2000-2012,
it was sighted in water as deep as 3,000 m, with the highest sighting
rates in water <500 m deep (Baird et al. 2013). It was seen during all
months, including off the west coast of the Island of Hawaii and off
Oahu (Baird et al. 2013). Spinner dolphins were also sighted in the
proposed survey area during summer-fall surveys of the Hawaiian Islands
EEZ, including south of Ohau (see map in Carretta et al. 2017); eight
sightings were made in 2002 (Barlow 2006) and four were made in 2010
(Bradford et al. 2013).
Kato et al. (2005) noted that spinner dolphins were seen during
Japanese sighting surveys in the western North Pacific in August-
September. To the best of our knowledge, there are no data on the
occurrence of spinner dolphins near the Emperor Seamounts survey area.
However, the survey area is located to the north of the known range of
the spinner dolphins. Therefore, they are not anticipated to occur in
the Emperor Seamounts area.
Striped Dolphin
The striped dolphin has a cosmopolitan distribution in tropical to
warm temperate waters from ~50[deg] N to 40[deg] S (Perrin et al.
1994a; Jefferson et al. 2015). It is typically found in waters outside
the continental shelf and is often associated with convergence zones
and areas of upwelling (Archer 2009). It occurs primarily in pelagic
waters, but has been observed approaching shore where there is deep
water close to the coast (Jefferson et al. 2015).
The striped dolphin is expected to be one of the most abundant
cetaceans in the proposed Hawaiian survey area, based on previous
surveys in the region (Barlow 2006; Baird et al. 2013; Bradford et al.
2017). Higher densities are expected to occur around in offshore waters
of the Hawaiian EEZ (Forney et al. 2015). During small-boat surveys
around the Hawaiian Islands in 2000-2012, sightings were made in water
depths of 1,000-5,000 m, with the highest sighting rates in water
deeper than 3000 m (Baird et al. 2013). Sightings were made during all
seasons, including near proposed seismic Line 1 off the Island of
Hawaii (Baird et al. 2013). It was also sighted within the proposed
survey area during summer-fall shipboard surveys of the Hawaii Islands
EEZ, including north and south of the Main Hawaiian Islands (see map in
Carretta et al. 2017); 15 sightings were made in 2002 (Barlow 2006) and
25 sightings were made in 2010 (Bradford et al. 2013).
In the western North Pacific, the striped dolphin was one of the
most common dolphin species seen during Japanese summer sighting
surveys (Miyashita 1993a). During these surveys, densities were highest
in offshore areas between 35[deg] N and 40[deg] N, and in coastal
waters of southeastern Japan (Miyashita 1993a). Although only part of
the proposed Emperor Seamounts survey area was surveyed during the
month of August, no sightings were made within the survey area;
sightings near the proposed survey area, south of 41[deg] N, were made
during August (Miyashita 1993a). Kanaji et al. (2017) reported on
another record during summer to the southwest of the survey area. One
winter bycatch record was reported just to the south of the survey area
for October 1990 to May 1991 (Hobbs and Jones 1993).
Based on its distributional range and habitat preferences, the
striped dolphin could be encountered in both the Hawaii and Emperor
Seamounts survey areas.
Fraser's Dolphin (Lagenodelphis hosei)
Fraser's dolphin is a tropical oceanic species distributed between
30[deg] N and 30[deg] S that generally inhabits deeper, offshore water
(Dolar 2009). It occurs rarely in temperate regions and then only in
relation to temporary oceanographic anomalies such as El Ni[ntilde]o
events (Perrin et al. 1994b). In the eastern tropical pacific, it was
sighted at
[[Page 30493]]
least 15 km from shore in waters 1,500-2,500 m deep (Dolar 2009).
Fraser's dolphin is one of the most abundant cetaceans in the
offshore waters of the Hawaiian Islands EEZ (Barlow 2006; Bradford et
al. 2017). Summer-fall shipboard surveys of the EEZ resulted in two
sightings of Fraser's dolphin in 2002 and four in 2010, all in the
western portion of the EEZ (Barlow 2006; Bradford et al. 2013; Carretta
et al. 2017). During small-boat surveys around the Hawaiian Islands in
2000-2012, only two sightings were made off the west coast of the
Island of Hawaii, one during winter and one during spring in water
deeper than 1000 m.
Fraser's dolphin was seen during Japanese sighting surveys in the
western North Pacific during August-September (Kato et al. 2005).
However, its range does not extend as far north as the Emperor
Seamounts survey area. Thus, Fraser's dolphin is not expected to occur
in the Emperor Seamounts survey area, but it could be encountered in
deep water of the Hawaii survey area.
Pacific White-Sided Dolphin
The Pacific white-sided dolphin is found throughout the temperate
North Pacific, in a relatively narrow distribution between 38[deg] N
and 47[deg] N (Brownell et al. 1999). It is common both on the high
seas and along the continental margins (Leatherwood et al. 1984;
Dahlheim and Towell 1994; Ferrero and Walker 1996). Pacific white-sided
dolphins often associate with other species, including cetaceans
(especially Risso's and northern right whale dolphins; Green et al.
1993), pinnipeds, and seabirds.
Pacific white-sided dolphins were seen throughout the North Pacific
during surveys conducted during 1983-1990 (Buckland et al. 1993;
Miyashita 1993b). Sightings were made in the western Pacific during the
summer (Buckland et al. 1993; Miyashita 1993b), as well as during
spring and fall (Buckland et al. 1993). Pacific white-sided dolphins
were observed in the southern portion of the Emperor Seamounts survey
area, south of 45[deg] S, as well as at higher latitudes just to the
east (Buckland et al. 1993; Miyashita 1993b). Bycatch in the squid
driftnet fishery has also been reported for the Emperor Seamounts
survey area (Hobbs and Jones 1993; Yatsu et al. 1993). Thus, Pacific
white-sided dolphins could be encountered in the Emperor Seamounts
survey area, but they are not known to occur as far south as Hawaii.
Northern Right Whale Dolphin
The northern right whale dolphin is found in cool temperate and
sub-arctic waters of the North Pacific, ranging from 34-55[deg] N
(Lipsky 2009). It occurs from the Kuril Islands south to Japan and
eastward to the Gulf of Alaska and southern California (Rice 1998). The
northern right whale dolphin is one of the most common marine mammal
species in the North Pacific, occurring primarily on the outer
continental shelf, slope waters, and oceanic regions, where water
depths are >100 m (see Green et al. 1993; Barlow 2003; Carretta et al.
2017). The northern right whale dolphin does, however, come closer to
shore where there is deep water, such as over submarine canyons
(Jefferson et al. 2015).
Northern right whale dolphins were seen throughout the North
Pacific during surveys conducted during 1983-1990, with sightings made
in the western Pacific primarily during the summer (Buckland et al.
1993; Miyashita 1993b). Northern right whale dolphins were observed in
the southern portion of the Emperor Seamounts survey area, south of
45[deg] S (Buckland et al. 1993; Miyashita 1993b). Bycatch records for
the Emperor Seamounts survey area have also been reported (Hobbs and
Jones 1993; Yatsu et al. 1993). One sighting was made just to the east
of the survey area, at a more northerly latitude (Miyashita 1993b).
Thus, northern right whale dolphins could be encountered in the Emperor
Seamounts survey area, but their distribution does not range as far
south as the Hawaiian Islands.
Risso's Dolphin
Risso's dolphin is primarily a tropical and mid-temperate species
distributed worldwide (Kruse et al. 1999). It occurs between 60[deg] N
and 60[deg] S, where surface water temperatures are at least 10[deg] C
(Kruse et al. 1999). Water temperature appears to be an important
factor affecting its distribution (Kruse et al. 1999). Although it
occurs from coastal to deep water, it shows a strong preference for
mid-temperate waters of the continental shelf and slope (Jefferson et
al. 2014).
During small-boat surveys around the Hawaiian Islands in 2000-2012,
sighting rates were highest in water >3,000 m deep (Baird et al. 2013).
Sightings were made during all seasons off the west coast of the Island
of Hawaii, including near proposed seismic Line 1; no sightings were
made off Oahu (Baird et al. 2013). During summer-fall surveys of the
Hawaiian Islands EEZ, seven sightings were made in 2002 (Barlow 2006)
and 10 were made in 2010 (Bradford et al. 2017); several sightings
occurred within the proposed survey area south of the Main Hawaiian
Islands (see map in Carretta et al. 2017).
Risso's dolphins were regularly seen during Japanese summer
sighting surveys in the western North Pacific (Miyashita 1993a), and
one individual was seen in the offshore waters east of Japan on 18
August 2010 during the Shatksy Rise cruise (Holst and Beland 2010).
Occurrence in the western North Pacific appears to be patchy, but high
densities were observed in coastal waters, between 148[deg] E-157[deg]
E, and east of 162[deg] E (Miyashita 1993a). Although only part of the
proposed Emperor Seamounts survey area was surveyed during the month of
August, no sightings were made within the survey area; however,
sightings were made south of 41[deg] N (Miyashita 1993a). As its
regular northern range extends to the southernmost portion of the
Emperor Seamounts survey area, and one record has been reported outside
of its range in the Aleutian Islands (Jefferson et al. 2014).
Therefore, the Risso's dolphin is expected to occur in the Emperor
Seamounts survey area.
Melon-Headed Whale
The melon-headed whale is an oceanic species found worldwide in
tropical and subtropical waters from ~40[deg] N to 35[deg] S (Jefferson
et al. 2015). It is commonly seen in mixed groups with other cetaceans
(Jefferson and Barros 1997; Huggins et al. 2005). It occurs most often
in deep offshore waters and occasionally in nearshore areas where deep
oceanic waters occur near the coast (Perryman 2009). In the North
Pacific, it is distributed south of central Japan and southern
California, as well as across the Pacific, including Hawaii.
Photo-identification and telemetry studies have revealed that there
are two distinct populations of melon-headed whales in Hawaiian
waters--the Hawaiian Islands stock and the Kohala resident stock
associated with the west coast of the Island of Hawaii (Aschettino et
al. 2012; Oleson et al. 2013; Carretta et al. 2017). Individuals in the
smaller Kohala resident stock have a limited range restricted to
shallower waters of the Kohala shelf and west side of Hawaii Island.
During small-boat surveys around the Hawaiian Islands in 2000-2012,
sightings were made during all seasons in all water depths up to 5,000
m, including sightings off the west coasts of the Island of Hawaii and
Oahu (Baird et al. 2013). There are numerous records near the proposed
seismic transect off the west coast of the Hawaiian Island (Carretta et
al. 2017); this area is considered a BIA (Baird et al. 2015). During
summer-fall surveys
[[Page 30494]]
of the Hawaiian Islands EEZ in 2002 and 2010, there was a single
sighting each year; neither was located near the proposed survey area
(Barlow et al. 2004; Bradford et al. 2017). Satellite telemetry data
revealed distant pelagic movements, associated with feeding, nearly to
the edge of the Hawaiian Islands EEZ (Oleson et al. 2013).
Melon-headed whales have been seen during Japanese sighting surveys
in the western North Pacific in August-September (Kato et al. 2005).
However, their distributional range does not extend to the Emperor
Seamounts survey area. Thus, melon-headed whale is expected to occur in
the proposed Hawaiian survey area, but not in the Emperor Seamounts
survey area.
Pygmy Killer Whale
The pygmy killer whale has a worldwide distribution in tropical and
subtropical waters (Donahue and Perryman 2009), generally not ranging
south of 35[deg] S (Jefferson et al. 2015). In warmer water, it is
usually seen close to the coast (Wade and Gerrodette 1993), but it is
also found in deep waters. In the North Pacific, it occurs from Japan
and Baja, California, southward and across the Pacific Ocean, including
Hawaii.
A small resident population inhabits the waters around the Main
Hawaiian Islands (Oleson et al. 2013), where it generally occurs within
~20 km from shore (Baird et al. 2011). During small-boat surveys around
the Hawaiian Islands in 2000-2012, sightings were made during all
seasons in water up to 3000 m deep, off the west coasts of Oahu and the
Island of Hawaii (Baird et al. 2013), including near proposed seismic
Lines 1 and 2. The waters off the west and southeast coasts of the
Island of Hawaii are considered a BIA (Baird et al. 2015). Pygmy killer
whales were also recorded during summer-fall surveys of the Hawaiian
Islands EEZ: Three sightings in 2002 (Barlow et al. 2004; Barlow 2006)
and five in 2010 (Bradford et al. 2017), including some within the
study area to the north and south of the Main Hawaiian Islands
(Carretta et al. 2017).
Kato et al. (2005) reported the occurrence of this species during
Japanese sighting surveys in the western North Pacific in August-
September. However, its distributional range indicates that the pygmy
killer whale is unlikely to occur in the Emperor Seamounts survey area.
False Killer Whale
The false killer whale is found worldwide in tropical and temperate
waters, generally between 50[deg] N and 50[deg] S (Odell and McClune
1999). It is widely distributed, but generally uncommon throughout its
range (Baird 2009). It is gregarious and forms strong social bonds, as
is evident from its propensity to strand en masse (Baird 2009). The
false killer whale generally inhabits deep, offshore waters, but
sometimes is found over the continental shelf and occasionally moves
into very shallow water (Jefferson et al. 2008; Baird 2009). In the
North Pacific, it occurs from Japan and southern California, southward
and across the Pacific, including Hawaii.
Telemetry, photo-identification, and genetic studies have
identified three independent populations of false killer whales in
Hawaiian waters: Main Hawaiian Islands Insular, Northwestern Hawaiian
Islands, and Hawaii pelagic stocks (Chivers et al. 2010; Baird et al.
2010, 2013; Bradford et al. 2014; Carretta et al. 2017). The range of
the Northwestern Hawaiian Islands stock is not the vicinity of the
Hawaii survey tracklines and, therefore, will not be discussed further.
The population inhabiting the Main Hawaiian Islands is thought to have
declined dramatically since 1989; the reasons for this decline are
still uncertain, although interactions with longline fisheries have
been suggested (Reeves et al. 2009; Bradford and Forney 2014). Higher
densities likely occur in the western-most areas of the Hawaiian EEZ
(Forney et al. 2015).
During 2008-2012, 26 false killer whales were observed hooked or
entangled by longline gear within the Hawaiian Islands EEZ or adjacent
high-seas waters, and 22 of those were assessed as seriously injured;
locations of false killer whale and unidentified blackfish takes
observed included the proposed survey area (Bradford and Forney 2014).
NMFS published a final rule to implement the False Killer Whale Take
Reduction Plan on November 29, 2012, 77 FR 71260). The final rule
includes gear requirements (``weak'' circle hooks and strong branch
lines) in the deep-set longline fishery, longline closure areas,
training and certification for vessel owners and captains in marine
mammal handling and release, captains' supervision of marine mammal
handling and release, and posting of placards on longline vessels.
Critical habitat has been proposed for the endangered insular
population of the false killer whale in Hawaii (82 FR 51186; November
3, 2017). In general, this includes waters between the 45- and 3,200-m
isobaths in the Main Hawaiian Islands (NNMFS 2017c). Note that in the
critical habitat proposal, NMFS invited the public to submit comments
on whether it is appropriate to include anthropogenic noise as a
feature essential to the conservation false killer whales in the final
rule. The final rule is expected to be published ~1 July 2018 (NMFS
2017c).
High-use areas in Hawaii include the north half of the Island of
Hawaii, the northern areas of Maui and Molokai, and southwest of Lanai
(Baird et al. 2012). These areas are considered BIAs (Baird et al.
2015), and proposed seismic Line 1 to the west of the Island of Hawaii
traverses the BIA. Individuals are found up to 122 km from shore (Baird
et al. 2012). Satellite-tagged false killer whales were also recorded
using the areas off the western Island of Hawaii and west of Oahu
during summer 2008 and fall 2009 (Baird et al. 2012). During small-boat
surveys around the Hawaiian Islands in 2000-2012, the highest sighting
rates occurred in water >3,500 m deep (Baird et al. 2013). Sightings
were made during all seasons, including off the west coast of the
Island of Hawaii and Oahu (Baird et al. 2013). During summer-fall
surveys of the Hawaiian Islands EEZ, two sightings were made in 2002
(Barlow et al. 2004; Barlow 2006) and 14 were made in 2010 (Bradford et
al. 2017), including two within the study area, south of the Main
Hawaiian Islands (see map in Carretta et al. 2017). False killer whales
were also detected acoustically off the west coast of the Hawaiian
Island and off Kauai (Baumann-Pickering et al. 2015).
False killer whales have been seen during Japanese summer sighting
surveys in the western Pacific Ocean (Miyashita 1993a), and a sighting
of four individuals was made in offshore waters east of Japan in August
2010 during the Shatksy Rise cruise (Holst and Beland 2010). The
distribution in the western Pacific was patchy, with several high-
density areas in offshore waters (Miyashita 1993a). Although only part
of the proposed Emperor Seamounts survey area was surveyed during the
month of August, no sightings were made within the survey area;
however, one sighting was made just to the southeast of the survey area
(Miyashita 1993a). Jefferson et al. (2015) did not show its
distributional range to include the Emperor Seamounts region.
False killer whale is expected to occur in the proposed Hawaiian
and Emperor Seamounts survey areas.
Killer Whale
The killer whale is cosmopolitan and globally fairly abundant; it
has been observed in all oceans of the World (Ford 2009). It is very
common in temperate waters and also frequents tropical waters, at least
seasonally
[[Page 30495]]
(Heyning and Dahlheim 1988). High densities of the species occur in
high latitudes, especially in areas where prey is abundant. Killer
whale movements generally appear to follow the distribution of their
prey, which includes marine mammals, fish, and squid.
Killer whales are rare in the Hawaii Islands EEZ. Baird et al.
(2006) reported 21 sighting records in Hawaiian waters between 1994 and
2004. During small-boat surveys around Hawaii Island in 2000-2012, a
single sighting was made during spring in water <2000 m deep off the
west coast of Hawaii Island (Baird et al. 2013). During summer--fall
surveys of the Hawaiian Islands EEZ, two sightings were made in 2002
(Barlow et al. 2004; Barlow 2006) and one was made in 2010 (Bradford et
al. 2017); none was made within the proposed survey area (Barlow et al.
2004; Bradford et al. 2017; Carretta et al. 2017). Numerous additional
sightings in and north of the EEZ have been made by observers on
longliners, some at the edge of the EEZ north of the Main Hawaiian
Islands (Carretta et al. 2017).
Very little is known about killer whale abundance and distribution
in the western Pacific Ocean outside of Kamchatka. However, they are
common along the coast of Russia, Sea of Okhotsk, and Sea of Japan,
Sakhalin Island, and Kuril Islands (Forney and Wade 2006). Kato et al.
(2005) reported sightings of this species during Japanese sighting
surveys in the western North Pacific in August-September. However,
there is very little information on killer whales for the Emperor
Seamounts survey area, but based on information regarding the
distribution and habitat preferences, they are likely to occur there
(see Forney and Wade 2006).
Killer whales are expected to occur in both the proposed Hawaiian
and Emperor survey areas.
Short-Finned Pilot Whale
The short-finned pilot whale is found in tropical and warm
temperate waters; it is seen as far south as ~40[deg] S and as far
north as 50[deg] N (Jefferson et al. 2015). It is generally nomadic,
but may be resident in certain locations, including Hawaii. Pilot
whales occur on the shelf break, over the slope, and in areas with
prominent topographic features (Olson 2009). Based on genetic data, Van
Cise et al. (2017) suggested that two types of short-finned pilot
whales occur in the Pacific--one in the western and central Pacific,
and one in the Eastern Pacific; they hypothesized that prey
distribution rather than sea surface temperature determine their
latitudinal ranges.
During surveys of the Main Hawaiian Islands during 2000-2012,
short-finned pilot whales were the most frequently sighted cetacean
(Baird et al. 2013). Higher densities are expected to occur around the
Hawaiian Islands rather than in far offshore waters of the Hawaiian EEZ
(Forney et al. 2015). Photo-identification and telemetry studies
indicate that there may be insular and pelagic populations of short-
finned pilot whales in Hawaii (Mahaffy 2012; Oleson et al. 2013).
Genetic research is also underway to assist in delimiting population
stocks for management (Carretta et al. 2017). During small-boat surveys
around the Hawaiian Islands in 2000-2012, pilot whales were sighted in
water as deep as 5,000 m, with the highest sighting rates in water
depths of 500-2,500 m (Baird et al. 2013). Sightings were made during
all seasons, mainly off the west coasts of the Island of Hawaii and
Ohau (Baird et al. 2013). The waters off the west coast of the Island
of Hawaii are considered a BIA (Baird et al. 2015); proposed seismic
tLine 1 traverses the BIA. During summer--fall surveys of the Hawaiian
Islands EEZ, 25 sightings were made in 2002 (Barlow 2006) and 36 were
made in 2010 (Bradford et al. 2017), including within the proposed
survey area, north, south, and between the Main Hawaiian Islands (see
Carretta et al. 2017). Short-finned pilot whales were also detected
acoustically off the west coast of the Island of Hawaii and off Kauai
(Baumann-Pickering et al. 2015).
Stock structure of short-finned pilot whales has not been
adequately studied in the North Pacific, except in Japanese waters,
where two stocks have been identified based on pigmentation patterns
and head shape differences of adult males (Kasuya et al. 1988). The
southern stock of short-finned pilot whales has been observed during
Japanese summer sightings surveys (Miyashita 1993a) and is
morphologically similar to pilot whales found in Hawaiian waters
(Carretta et al. 2017). Distribution of short-finned pilot whales in
the western North Pacific appears to be patchy, but high densities were
observed in coastal waters of central and southern Japan and in some
areas offshore (Miyashita 1993a). A sighting of three individuals was
made in offshore waters east of Japan in August 2010 during the Shatksy
Rise cruise (Holst and Beland 2010). Although only part of the proposed
Emperor Seamounts survey area was surveyed during the month of August,
no sightings were made within or near the survey area; offshore
sightings to the south of the proposed survey area were made during the
month of September (Miyashita 1993a). Although Jefferson et al. (2015)
did not include the Emperor Seamounts region in its distributional
range, Olson (2009) did.
Short-finned pilot whales are expected to occur in both the
proposed Hawaiian and Emperor Seamounts survey areas.
Dall's Porpoise
Dall's porpoise is only found in the North Pacific and adjacent
seas. It is widely distributed across the North Pacific over the
continental shelf and slope waters, and over deep (>2500 m) oceanic
waters (Hall 1979), ranging from ~30-62[deg] N (Jefferson et al. 2015).
In general, this species is common throughout its range (Buckland et
al. 1993). It is known to approach vessels to bowride (Jefferson
2009b).
In the western North Pacific, there are two different color morphs
which are also considered sub-species: The truei-type (P. d. truei) and
the dalli-type (P. d. dalli) (Jefferson et al. 2015). They can be
distinguished from each other by the extent of their white thoracic
patches--the truei-type has a much broader patch, which extends nearly
the length of the body. Both types could be encountered in the proposed
Emperor Seamounts survey area.
Dall's porpoise was one of the most common cetaceans in the bycatch
of the central and western North Pacific high-seas driftnet fisheries,
but that source of mortality is not thought to have substantially
depleted their abundance in the region (Hobbs and Jones 1993). Dall's
porpoises were seen throughout the North Pacific during surveys
conducted during 1987-1990 (Buckland et al. 1993), including in the
western Pacific during the summer (Buckland et al. 1993; Kato et al.
2005). The observed range included the entire Emperor Seamounts survey
area (Buckland et al. 1993). Records of both types within the Emperor
Seamounts survey area, in particular for April-July, have also been
reported by Kasuya (1982), and bycatch records in the proposed survey
area have also been reported (Hobbs and Jones 1993; Yatsu et al. 1993).
Thus, Dall's porpoise could be encountered in the Emperor Seamounts
survey area, but its distribution does not range as far south as the
Hawaiian Islands.
Hawaiian Monk Seal
The Hawaiian monk seal only occurs in the Central North Pacific. It
is distributed throughout the Hawaiian Island chain, with most of the
population occurring in the Northwestern Hawaiian Islands (within the
PMNM), and a small but increasing
[[Page 30496]]
number residing in the Main Hawaiian Islands (Baker et al. 2011). Six
main breeding subpopulations are located at the Kure Atoll, Midway
Islands, Pearl and Hermes Reef, Lisianski Island, Laysan Island, and
French Frigate Shoals (Baker et al. 2011). Most births occur from
February to August, with a peak in April to June, but births have been
reported any time of the year (Gilmartin and Forcada 2009). Hawaiian
monk seals show high site fidelity to natal islands (Gilmartin and
Forcada 2009; Wilson et al. 2017). They mainly occur within 50 km of
atolls/islands (Parrish et al. 2000; Stewart et al. 2006; Wilson et al.
2017) and within the 500-m isobath (e.g., Parrish et al. 2002; Wilson
et al. 2017). Secondary occurrence may occur in water as deep as 1000
m, but occurrence beyond the 1000-m isobath is rare (DoN 2005).
Nonetheless, tagged monk seals have been tracked in water >1000 m deep
(Wilson et al. 2017).
Hawaiian monk seals are benthic foragers that feed on marine
terraces of atolls and banks; most foraging occurs in water depths <100
m deep but occasionally to depths up to 500 m (Parrish et al. 2002;
Stewart et al. 2006). Stewart et al. (2006) used satellite tracking to
examine the foraging behavior of monk seals at the six main breeding
colonies in the Northwestern Hawaiian Islands. Foraging trips varied by
sex and by age and ranged from <1 km up to 322 km from haul-out sites.
Wilson et al. (2017) reported foraging trips of up to 100 km. Satellite
tracking of Hawaiian monk seals revealed that home ranges in Main
Hawaiian Islands were much smaller than those in the Northwestern
Hawaiian Islands (NMFS 2007, 2014); home ranges for most seals were
<2000 km\2\ (Wilson et al. 2017).
Critical habitat has been designated based on preferred pupping and
nursing areas, significant haul-out areas, and marine foraging areas
out to a depth of 200 m (NMFS 2017b). In the Main Hawaiian Islands,
critical habitat generally includes marine habitat from the seafloor to
10 m above the seafloor, from the 200-m isobath to the shoreline and 5
m inland, with some exceptions for specific areas (NMFS 2017b). For the
Island of Hawaii of Hawaii, Maui, and Oahu (islands adjacent to the
proposed transects), all marine habitat and inland habitat is included
as critical habitat (NMFS 2017b). The seismic transects are located at
least 10 km from monk seal critical habitat (Fig. 1).
Hawaiian monk seals have been reported throughout the Main Hawaiian
Islands, including the west coast of Oahu, the east coast of Maui, and
the north coast of the Island of Hawaii (Baker and Johanos 2004; DoN
2005). Tagged seals showed movements among the Main Hawaiian Islands,
and were reported to occur near and crossing proposed seismic Lines 1
and 2 off the west coast of Oahu and the Island of Hawaii (Wilson et
al. 2017). However, the core area of occurrence around Oahu was
reported to be off the south coast, not the west coast (Wilson et al.
2017). Thus, monk seals could be encountered during the proposed
survey, especially in nearshore portions (<1000 m deep), as well as
areas near the islands where water depth is greater than >1000 m.
Northern Fur Seal
The northern fur seal is endemic to the North Pacific Ocean and
occurs from southern California to the Bering Sea, Okhotsk Sea, and
Honshu Island, Japan (Muto et al. 2017). During the breeding season,
most of the worldwide population of northern fur seals inhabits the
Pribilof Islands in the southern Bering Sea (Lee et al. 2014; Muto et
al. 2017). The rest of the population occurs at rookeries on Bogoslof
Island in the Bering Sea, in Russia (Commander Islands, Robben Island,
Kuril Islands), on San Miguel Island in southern California (NMFS 1993;
Lee et al. 2014), and on the Farallon Islands off central California
(Muto et al. 2017). In the United States, two stocks are recognized--
the Eastern Pacific and the California stocks (Muto et al. 2017). The
Eastern Pacific stock ranges from the Pribilof Islands and Bogoslof
Island in the Bering Sea during summer to California during winter
(Muto et al. 2017).
When not on rookery islands, northern fur seals are primarily
pelagic but occasionally haul out on rocky shorelines (Muto et al.
2017). During the breeding season, adult males usually come ashore in
May-August and may sometimes be present until November; adult females
are found ashore from June-November (Carretta et al. 2017; Muto et al.
2017). After reproduction, northern fur seals spend the next 7-8 months
feeding at sea (Roppel 1984). Once weaned, juveniles spend 2-3 years at
sea before returning to rookeries. Animals may migrate to the Gulf of
Alaska, off Japan, and the west coast of the United States (Muto et al.
2017); in particular, adult males from the Pripilof Islands have been
shown to migrate to the Kuril Islands in the western Pacific (Loughlin
et al. 1999). The southern extent of the migration is ~35 N.
Northern fur seals were seen throughout the North Pacific during
surveys conducted during 1987-1990, including in the western Pacific
during the summer (Buckland et al. 1993). The observed range included
the entire Emperor Seamounts survey area (Buckland et al. 1993). They
have also been reported as bycatch in squid and large-mesh fisheries
during summer in the Emperor Seamounts survey area (Hobbs and Jones
1993; Yatsu et al. 1993). Tracked adult male fur seals that were tagged
on St. Paul Island in the Bering Sea in October 2009, wintered in the
Bering Sea or northern North Pacific Ocean, and approached near the
eastern-most extent of the Emperor Seamounts survey area; females
migrated to the Gulf of Alaska and the California Current (Sterling et
al. 2014). Tagged pups also approached the eastern portion of the
Emperor Seamounts survey area during November (Lea et al. 2009). Thus,
northern fur seals could be encountered in the Emperor Seamounts survey
area; only juveniles would be expected to occur there during the
summer. Their distribution does not range as far south as the Hawaiian
Islands.
Northern Elephant Seal
Northern elephant seals breed in California and Baja California,
primarily on offshore islands (Stewart et al. 1994), from December-
March (Stewart and Huber 1993). Adult elephant seals engage in two long
northward migrations per year, one following the breeding season, and
another following the annual molt, with females returning earlier to
molt (March-April) than males (July-August) (Stewart and DeLong 1995).
Juvenile elephant seals typically leave the rookeries in April or May
and head north, traveling an average of 900-1,000 km. Hindell (2009)
noted that traveling likely takes place in water depths >200 m.
When not breeding, elephant seals feed at sea far from the
rookeries, ranging as far north as 60[deg] N, into the Gulf of Alaska
and along the Aleutian Islands (Le Boeuf et al. 2000). Some seals that
were tracked via satellite-tags for no more than 224 days traveled
distances in excess of 10,000 km during that time (Le Beouf et al.
2000). Northern elephant seals that were satellite-tagged at a
California rookery have been recorded traveling as far west as ~166.5-
172.5[deg] E, including the proposed Emperor Seamount survey area (Le
Boeuf et al. 2000; Robinson et al. 2012; Robinson 2016 in OBIS 2018;
Costa 2017 in OBIS 2018). Occurrence in the survey area was documented
during August and September; during July and October, northern elephant
seals were tracked just to the east of the survey area (Robinson et al.
2012). Post-molting seals traveled longer and farther
[[Page 30497]]
than post-breeding seals (Robinson et al. 2012).
Thus, northern elephant seals could be encountered in the Emperor
Seamounts survey area during summer and fall. Although there are rare
records of northern elephant seals in Hawaiian waters, they are
unlikely to occur in the proposed survey area.
Ribbon Seal
Ribbon seals occur in the North Pacific and adjacent Arctic Ocean,
ranging from the Okhotsk Sea, to the Aleutian Islands and the Bering,
Chukchi, and western Beaufort seas. Ribbon seals inhabit the Bering Sea
ice front from late-March to early-May and are abundant in the northern
parts of the ice front in the central and western parts of the Bering
Sea (Burns 1970; Burns 1981). In May to mid-July, when the ice recedes,
some of the seals move farther north (Burns 1970; Burns 1981) to the
Chukchi Sea (Kelly 1988c). However, most likely become pelagic and
remain in the Bering Sea during the open-water season, and some occur
on the Pacific Ocean side of the Aleutian Islands (Boveng et al. 2008).
Of 10 seals that were tagged along the cost of the Kamchatka Peninsula
in 2005, most stayed in the central and eastern Bering Sea, but two
were tracked along the south side of the Aleutian Islands; 8 of 26
seals that were tagged in the central Bering Sea in 2007 traveled to
the Bering Strait, Chukchi Sea, and Arctic Basin (Boveng et al. 2008).
Although unlikely ribbon seals could be encountered in the proposed
Emperor Seamounts survey area.
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 (2016) described
generalized hearing ranges for these marine mammal hearing groups.
Generalized hearing ranges were chosen based on the approximately 65 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. The functional groups and the associated
frequencies are indicated below (note that these frequency ranges
correspond to the range for the composite group, with the entire range
not necessarily reflecting the capabilities of every species within
that group):
Low-frequency cetaceans (mysticetes): Generalized hearing is
estimated to occur between approximately 7 Hz and 35 kHz;
Mid-frequency cetaceans (larger toothed whales, beaked whales,
and most delphinids): Generalized hearing is estimated to occur between
approximately 150 Hz and 160 kHz;
High-frequency cetaceans (porpoises, river dolphins, and
members of the genera Kogia and Cephalorhynchus; including two members
of the genus Lagenorhynchus, on the basis of recent echolocation data
and genetic data): generalized hearing is estimated to occur between
approximately 275 Hz and 160 kHz.
Pinnipeds in water; Phocidae (true seals): Generalized hearing
is estimated to occur between approximately 50 Hz to 86 kHz;
Pinnipeds in water; Otariidae (eared seals): Generalized
hearing is estimated to occur between 60 Hz and 39 kHz.
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 (2016) for a review of available information.
Forty marine mammal species (36 cetacean and 4 pinniped (1 otariid and
3 phocid) species) have the reasonable potential to co-occur with the
proposed survey activities. Please refer to Table 1. Of the cetacean
species that may be present, 8 are classified as low-frequency
cetaceans (i.e., all mysticete species), 25 are classified as mid-
frequency cetaceans (i.e., all delphinid and ziphiid species and the
sperm whale), and 3 are classified as high-frequency cetaceans (i.e.,
Dall's porpoise and Kogia spp.).
Potential Effects of Specified Activities on Marine Mammals and Their
Habitat
This section includes a summary and discussion of the ways that
components of the specified activity may impact marine mammals and
their habitat. The ``Estimated Take by Incidental Harassment'' section
later in this document includes a quantitative analysis of the number
of individuals that are expected to be taken by this activity. The
``Negligible Impact Analysis and Determination'' section considers the
content of this section, the ``Estimated Take by Incidental
Harassment'' section, and the ``Proposed Mitigation'' section, to draw
conclusions regarding the likely impacts of these activities on the
reproductive success or survivorship of individuals and how those
impacts on individuals are likely to impact marine mammal species or
stocks.
Description of Active Acoustic Sound Sources
This section contains a brief technical background on sound, the
characteristics of certain sound types, and on metrics used in this
proposal inasmuch as the information is relevant to the specified
activity and to a discussion of the potential effects of the specified
activity on marine mammals found later in this document.
Sound travels in waves, the basic components of which are
frequency, wavelength, velocity, and amplitude. Frequency is the number
of pressure waves that pass by a reference point per unit of time and
is measured in Hz or cycles per second. Wavelength is the distance
between two peaks or corresponding points of a sound wave (length of
one cycle). Higher frequency sounds have shorter wavelengths than lower
frequency sounds, and typically attenuate (decrease) more rapidly,
except in certain cases in shallower water. Amplitude is the height of
the sound pressure wave or the ``loudness'' of a sound and is typically
described using the relative unit of the decibel (dB). A sound pressure
level (SPL) in dB is described as the ratio between a measured pressure
and a reference pressure (for underwater sound, this is 1 microPascal
([mu]Pa)) and is a logarithmic unit that accounts for large variations
in amplitude; therefore, a relatively small change in dB corresponds to
large changes in sound pressure. The source level (SL) represents the
SPL referenced at a distance of 1 m from the source
[[Page 30498]]
(referenced to 1 [mu]Pa) while the received level is the SPL at the
listener's position (referenced to 1 [mu]Pa).
Root mean square (rms) is the quadratic mean sound pressure over
the duration of an impulse. Root mean square is calculated by squaring
all of the sound amplitudes, averaging the squares, and then taking the
square root of the average (Urick, 1983). Root mean square accounts for
both positive and negative values; squaring the pressures makes all
values positive so that they may be accounted for in the summation of
pressure levels (Hastings and Popper, 2005). This measurement is often
used in the context of discussing behavioral effects, in part because
behavioral effects, which often result from auditory cues, may be
better expressed through averaged units than by peak pressures.
Sound exposure level (SEL; represented as dB re 1 [mu]Pa\2\-s)
represents the total energy contained within a puls and considers both
intensity and duration of exposure. Peak sound pressure (also referred
to as zero-to-peak sound pressure or 0-p) is the maximum instantaneous
sound pressure measurable in the water at a specified distance from the
source and is represented in the same units as the rms sound pressure.
Another common metric is peak-to-peak sound pressure (pk-pk), which is
the algebraic difference between the peak positive and peak negative
sound pressures. Peak-to-peak pressure is typically approximately 6 dB
higher than peak pressure (Southall et al., 2007).
When underwater objects vibrate or activity occurs, sound-pressure
waves are created. These waves alternately compress and decompress the
water as the sound wave travels. Underwater sound waves radiate in a
manner similar to ripples on the surface of a pond and may be either
directed in a beam or beams or may radiate in all directions
(omnidirectional sources), as is the case for pulses produced by the
airgun arrays considered here. The compressions and decompressions
associated with sound waves are detected as changes in pressure by
aquatic life and man-made sound receptors such as hydrophones.
Even in the absence of sound from the specified activity, the
underwater environment is typically loud due to ambient sound. Ambient
sound is defined as environmental background sound levels lacking a
single source or point (Richardson et al., 1995), and the sound level
of a region is defined by the total acoustical energy being generated
by known and unknown sources. These sources may include physical (e.g.,
wind and waves, earthquakes, ice, atmospheric sound), biological (e.g.,
sounds produced by marine mammals, fish, and invertebrates), and
anthropogenic (e.g., vessels, dredging, construction) sound. A number
of sources contribute to ambient sound, including the following
(Richardson et al., 1995):
Wind and waves: The complex interactions between wind and
water surface, including processes such as breaking waves and wave-
induced bubble oscillations and cavitation, are a main source of
naturally occurring ambient sound for frequencies between 200 Hz and 50
kHz (Mitson, 1995). In general, ambient sound levels tend to increase
with increasing wind speed and wave height. Surf sound becomes
important near shore, with measurements collected at a distance of 8.5
km from shore showing an increase of 10 dB in the 100 to 700 Hz band
during heavy surf conditions.
Precipitation: Sound from rain and hail impacting the
water surface can become an important component of total sound at
frequencies above 500 Hz, and possibly down to 100 Hz during quiet
times.
Biological: Marine mammals can contribute significantly to
ambient sound levels, as can some fish and snapping shrimp. The
frequency band for biological contributions is from approximately 12 Hz
to over 100 kHz.
Anthropogenic: Sources of ambient sound related to human
activity include transportation (surface vessels), dredging and
construction, oil and gas drilling and production, seismic surveys,
sonar, explosions, and ocean acoustic studies. Vessel noise typically
dominates the total ambient sound for frequencies between 20 and 300
Hz. In general, the frequencies of anthropogenic sounds are below 1 kHz
and, if higher frequency sound levels are created, they attenuate
rapidly. Sound from identifiable anthropogenic sources other than the
activity of interest (e.g., a passing vessel) is sometimes termed
background sound, as opposed to ambient sound.
The sum of the various natural and anthropogenic sound sources at
any given location and time--which comprise ``ambient'' or
``background'' sound--depends not only on the source levels (as
determined by current weather conditions and levels of biological and
human activity) but also on the ability of sound to propagate through
the environment. In turn, sound propagation is dependent on the
spatially and temporally varying properties of the water column and sea
floor, and is frequency-dependent. As a result of the dependence on a
large number of varying factors, ambient sound levels can be expected
to vary widely over both coarse and fine spatial and temporal scales.
Sound levels at a given frequency and location can vary by 10-20 dB
from day to day (Richardson et al., 1995). The result is that,
depending on the source type and its intensity, sound from a given
activity may be a negligible addition to the local environment or could
form a distinctive signal that may affect marine mammals. Details of
source types are described in the following text.
Sounds are often considered to fall into one of two general types:
Pulsed and non-pulsed (defined in the following). The distinction
between these two sound types is important because they have differing
potential to cause physical effects, particularly with regard to
hearing (e.g., Ward, 1997 in Southall et al., 2007). Please see
Southall et al. (2007) for an in-depth discussion of these concepts.
Pulsed sound sources (e.g., airguns, explosions, gunshots, sonic
booms, impact pile driving) produce signals that are brief (typically
considered to be less than one second), broadband, atonal transients
(ANSI, 1986, 2005; Harris, 1998; NIOSH, 1998; ISO, 2003) and occur
either as isolated events or repeated in some succession. Pulsed sounds
are all characterized by a relatively rapid rise from ambient pressure
to a maximal pressure value followed by a rapid decay period that may
include a period of diminishing, oscillating maximal and minimal
pressures, and generally have an increased capacity to induce physical
injury as compared with sounds that lack these features.
Non-pulsed sounds can be tonal, narrowband, or broadband, brief or
prolonged, and may be either continuous or non-continuous (ANSI, 1995;
NIOSH, 1998). Some of these non-pulsed sounds can be transient signals
of short duration but without the essential properties of pulses (e.g.,
rapid rise time). Examples of non-pulsed sounds include those produced
by vessels, aircraft, machinery operations such as drilling or
dredging, vibratory pile driving, and active sonar systems (such as
those used by the U.S. Navy). The duration of such sounds, as received
at a distance, can be greatly extended in a highly reverberant
environment.
Airgun arrays produce pulsed signals with energy in a frequency
range from about 10-2,000 Hz, with most energy radiated at frequencies
below 200 Hz. The amplitude of the acoustic wave emitted from the
source is equal in all directions (i.e., omnidirectional), but airgun
arrays do possess some
[[Page 30499]]
directionality due to different phase delays between guns in different
directions. Airgun arrays are typically tuned to maximize functionality
for data acquisition purposes, meaning that sound transmitted in
horizontal directions and at higher frequencies is minimized to the
extent possible.
As described above, a Kongsberg EM 122 MBES, a Knudsen Chirp 3260
SBP, and a Teledyne RDI 75 kHz Ocean Surveyor ADCP would be operated
continuously during the proposed surveys, but not during transit to and
from the survey areas. Due to the lower source level of the Kongsberg
EM 122 MBES relative to the Langseth's airgun array (242 dB re 1 [mu]Pa
[middot] m for the MBES versus a minimum of 258 dB re 1 [mu]Pa [middot]
m (rms) for the 36 airgun array (NSF-USGS, 2011), sounds from the MBES
are expected to be effectively subsumed by the sounds from the airgun
array. Thus, any marine mammal potentially exposed to sounds from the
MBES would already have been exposed to sounds from the airgun array,
which are expected to propagate further in the water. Each ping emitted
by the MBES consists of eight (in water >1,000 m deep) or four (<1,000
m) successive fan-shaped transmissions, each ensonifying a sector that
extends 1[deg] fore-aft. Given the movement and speed of the vessel,
the intermittent and narrow downward-directed nature of the sounds
emitted by the MBES would result in no more than one or two brief ping
exposures of any individual marine mammal, if any exposure were to
occur.
Due to the lower source levels of both the Knudsen Chirp 3260 SBP
and the Teledyne RDI 75 kHz Ocean Surveyor ADCP relative to the
Langseth's airgun array (maximum SL of 222 dB re 1 [mu]Pa [middot] m
for the SBP and maximum SL of 224 dB re 1 [mu]Pa [middot] m for the
ADCP, versus a minimum of 258 dB re 1 [mu]Pa [middot] m for the 36
airgun array (NSF-USGS, 2011), sounds from the SBP and ADCP are
expected to be effectively subsumed by sounds from the airgun array.
Thus, any marine mammal potentially exposed to sounds from the SBP and/
or the ADCP would already have been exposed to sounds from the airgun
array, which are expected to propagate further in the water. As such,
we conclude that the likelihood of marine mammal take resulting from
exposure to sound from the MBES, SBP or ADCP is discountable and
therefore we do not consider noise from the MBES, SBP or ADCP further
in this analysis.
Acoustic Effects
Here, we discuss the effects of active acoustic sources on marine
mammals.
Potential Effects of Underwater Sound--Please refer to the
information given previously (``Description of Active Acoustic
Sources'') regarding sound, characteristics of sound types, and metrics
used in this document. Anthropogenic sounds cover a broad range of
frequencies and sound levels and can have a range of highly variable
impacts on marine life, from none or minor to potentially severe
responses, depending on received levels, duration of exposure,
behavioral context, and various other factors. The potential effects of
underwater sound from active acoustic sources can potentially result in
one or more of the following: Temporary or permanent hearing
impairment, non-auditory physical or physiological effects, behavioral
disturbance, stress, and masking (Richardson et al., 1995; Gordon et
al., 2004; Nowacek et al., 2007; Southall et al., 2007; G[ouml]tz et
al., 2009). The degree of effect is intrinsically related to the signal
characteristics, received level, distance from the source, and duration
of the sound exposure. In general, sudden, high level sounds can cause
hearing loss, as can longer exposures to lower level sounds. Temporary
or permanent loss of hearing will occur almost exclusively for noise
within an animal's hearing range. We first describe specific
manifestations of acoustic effects before providing discussion specific
to the use of airgun arrays.
Richardson et al. (1995) described zones of increasing intensity of
effect that might be expected to occur, in relation to distance from a
source and assuming that the signal is within an animal's hearing
range. First is the area within which the acoustic signal would be
audible (potentially perceived) to the animal, but not strong enough to
elicit any overt behavioral or physiological response. The next zone
corresponds with the area where the signal is audible to the animal and
of sufficient intensity to elicit behavioral or physiological
responsiveness. Third is a zone within which, for signals of high
intensity, the received level is sufficient to potentially cause
discomfort or tissue damage to auditory or other systems. Overlaying
these zones to a certain extent is the area within which masking (i.e.,
when a sound interferes with or masks the ability of an animal to
detect a signal of interest that is above the absolute hearing
threshold) may occur; the masking zone may be highly variable in size.
We describe the more severe effects of certain non-auditory
physical or physiological effects only briefly as we do not expect that
use of airgun arrays are reasonably likely to result in such effects
(see below for further discussion). Potential effects from impulsive
sound sources can range in severity from effects such as behavioral
disturbance or tactile perception to physical discomfort, slight injury
of the internal organs and the auditory system, or mortality (Yelverton
et al., 1973). Non-auditory physiological effects or injuries that
theoretically might occur in marine mammals exposed to high level
underwater sound or as a secondary effect of extreme behavioral
reactions (e.g., change in dive profile as a result of an avoidance
reaction) caused by exposure to sound include neurological effects,
bubble formation, resonance effects, and other types of organ or tissue
damage (Cox et al., 2006; Southall et al., 2007; Zimmer and Tyack,
2007; Tal et al., 2015). The survey activities considered here do not
involve the use of devices such as explosives or mid-frequency tactical
sonar that are associated with these types of effects.
Threshold Shift--Marine mammals exposed to high-intensity sound, or
to lower-intensity sound for prolonged periods, can experience hearing
threshold shift (TS), which is the loss of hearing sensitivity at
certain frequency ranges (Finneran, 2015). TS can be permanent (PTS),
in which case the loss of hearing sensitivity is not fully recoverable,
or temporary (TTS), in which case the animal's hearing threshold would
recover over time (Southall et al., 2007). Repeated sound exposure that
leads to TTS could cause PTS. In severe cases of PTS, there can be
total or partial deafness, while in most cases the animal has an
impaired ability to hear sounds in specific frequency ranges (Kryter,
1985).
When PTS occurs, there is physical damage to the sound receptors in
the ear (i.e., tissue damage), whereas TTS represents primarily tissue
fatigue and is reversible (Southall et al., 2007). In addition, other
investigators have suggested that TTS is within the normal bounds of
physiological variability and tolerance and does not represent physical
injury (e.g., Ward, 1997). Therefore, NMFS does not consider TTS to
constitute auditory injury.
Relationships between TTS and PTS thresholds have not been studied
in marine mammals, and there is no PTS data for cetaceans but such
relationships are assumed to be similar to those in humans and other
terrestrial mammals. PTS typically occurs at exposure levels at least
several decibels above (a 40-dB threshold shift approximates PTS onset;
e.g., Kryter et al., 1966; Miller, 1974) that inducing mild TTS (a 6-dB
threshold shift approximates TTS onset; e.g., Southall et al. 2007).
Based on data
[[Page 30500]]
from terrestrial mammals, a precautionary assumption is that the PTS
thresholds for impulse sounds (such as airgun pulses as received close
to the source) are at least 6 dB higher than the TTS threshold on a
peak-pressure basis and PTS cumulative sound exposure level thresholds
are 15 to 20 dB higher than TTS cumulative sound exposure level
thresholds (Southall et al., 2007). Given the higher level of sound or
longer exposure duration necessary to cause PTS as compared with TTS,
it is considerably less likely that PTS could occur.
For mid-frequency cetaceans in particular, potential protective
mechanisms may help limit onset of TTS or prevent onset of PTS. Such
mechanisms include dampening of hearing, auditory adaptation, or
behavioral amelioration (e.g., Nachtigall and Supin, 2013; Miller et
al., 2012; Finneran et al., 2015; Popov et al., 2016).
TTS is the mildest form of hearing impairment that can occur during
exposure to sound (Kryter, 1985). While experiencing TTS, the hearing
threshold rises, and a sound must be at a higher level in order to be
heard. In terrestrial and marine mammals, TTS can last from minutes or
hours to days (in cases of strong TTS). In many cases, hearing
sensitivity recovers rapidly after exposure to the sound ends. Few data
on sound levels and durations necessary to elicit mild TTS have been
obtained for marine mammals.
Marine mammal hearing plays a critical role in communication with
conspecifics, and interpretation of environmental cues for purposes
such as predator avoidance and prey capture. Depending on the degree
(elevation of threshold in dB), duration (i.e., recovery time), and
frequency range of TTS, and the context in which it is experienced, TTS
can have effects on marine mammals ranging from discountable to
serious. For example, a marine mammal may be able to readily compensate
for a brief, relatively small amount of TTS in a non-critical frequency
range that occurs during a time where ambient noise is lower and there
are not as many competing sounds present. Alternatively, a larger
amount and longer duration of TTS sustained during time when
communication is critical for successful mother/calf interactions could
have more serious impacts.
Finneran et al. (2015) measured hearing thresholds in three captive
bottlenose dolphins before and after exposure to ten pulses produced by
a seismic airgun in order to study TTS induced after exposure to
multiple pulses. Exposures began at relatively low levels and gradually
increased over a period of several months, with the highest exposures
at peak SPLs from 196 to 210 dB and cumulative (unweighted) SELs from
193-195 dB. No substantial TTS was observed. In addition, behavioral
reactions were observed that indicated that animals can learn behaviors
that effectively mitigate noise exposures (although exposure patterns
must be learned, which is less likely in wild animals than for the
captive animals considered in this study). The authors note that the
failure to induce more significant auditory effects likely due to the
intermittent nature of exposure, the relatively low peak pressure
produced by the acoustic source, and the low-frequency energy in airgun
pulses as compared with the frequency range of best sensitivity for
dolphins and other mid-frequency cetaceans.
Currently, TTS data only exist for four species of cetaceans
(bottlenose dolphin, beluga whale, harbor porpoise, and Yangtze finless
porpoise) exposed to a limited number of sound sources (i.e., mostly
tones and octave-band noise) in laboratory settings (Finneran, 2015).
In general, harbor porpoises have a lower TTS onset than other measured
cetacean species (Finneran, 2015). Additionally, the existing marine
mammal TTS data come from a limited number of individuals within these
species. There are no data available on noise-induced hearing loss for
mysticetes.
Critical questions remain regarding the rate of TTS growth and
recovery after exposure to intermittent noise and the effects of single
and multiple pulses. Data at present are also insufficient to construct
generalized models for recovery and determine the time necessary to
treat subsequent exposures as independent events. More information is
needed on the relationship between auditory evoked potential and
behavioral measures of TTS for various stimuli. For summaries of data
on TTS in marine mammals or for further discussion of TTS onset
thresholds, please see Southall et al. (2007), Finneran and Jenkins
(2012), Finneran (2015), and NMFS (2016).
Behavioral Effects--Behavioral disturbance may include a variety of
effects, including subtle changes in behavior (e.g., minor or brief
avoidance of an area or changes in vocalizations), more conspicuous
changes in similar behavioral activities, and more sustained and/or
potentially severe reactions, such as displacement from or abandonment
of high-quality habitat. Behavioral responses to sound are highly
variable and context-specific and any reactions depend on numerous
intrinsic and extrinsic factors (e.g., species, state of maturity,
experience, current activity, reproductive state, auditory sensitivity,
time of day), as well as the interplay between factors (e.g.,
Richardson et al., 1995; Wartzok et al., 2003; Southall et al., 2007;
Weilgart, 2007; Archer et al., 2010). Behavioral reactions can vary not
only among individuals but also within an individual, depending on
previous experience with a sound source, context, and numerous other
factors (Ellison et al., 2012), and can vary depending on
characteristics associated with the sound source (e.g., whether it is
moving or stationary, number of sources, distance from the source).
Please see Appendices B-C of Southall et al. (2007) for a review of
studies involving marine mammal behavioral responses to sound.
Habituation can occur when an animal's response to a stimulus wanes
with repeated exposure, usually in the absence of unpleasant associated
events (Wartzok et al., 2003). Animals are most likely to habituate to
sounds that are predictable and unvarying. It is important to note that
habituation is appropriately considered as a ``progressive reduction in
response to stimuli that are perceived as neither aversive nor
beneficial,'' rather than as, more generally, moderation in response to
human disturbance (Bejder et al., 2009). The opposite process is
sensitization, when an unpleasant experience leads to subsequent
responses, often in the form of avoidance, at a lower level of
exposure. As noted, behavioral state may affect the type of response.
For example, animals that are resting may show greater behavioral
change in response to disturbing sound levels than animals that are
highly motivated to remain in an area for feeding (Richardson et al.,
1995; NRC, 2003; Wartzok et al., 2003). Controlled experiments with
captive marine mammals have showed pronounced behavioral reactions,
including avoidance of loud sound sources (Ridgway et al., 1997).
Observed responses of wild marine mammals to loud pulsed sound sources
(typically seismic airguns or acoustic harassment devices) have been
varied but often consist of avoidance behavior or other behavioral
changes suggesting discomfort (Morton and Symonds, 2002; see also
Richardson et al., 1995; Nowacek et al., 2007). However, many
delphinids approach acoustic source vessels with no apparent discomfort
or obvious behavioral change (e.g., Barkaszi et al., 2012).
[[Page 30501]]
Available studies show wide variation in response to underwater
sound; therefore, it is difficult to predict specifically how any given
sound in a particular instance might affect marine mammals perceiving
the signal. If a marine mammal does react briefly to an underwater
sound by changing its behavior or moving a small distance, the impacts
of the change are unlikely to be significant to the individual, let
alone the stock or population. However, if a sound source displaces
marine mammals from an important feeding or breeding area for a
prolonged period, impacts on individuals and populations could be
significant (e.g., Lusseau and Bejder, 2007; Weilgart, 2007; NRC,
2005). However, there are broad categories of potential response, which
we describe in greater detail here, that include alteration of dive
behavior, alteration of foraging behavior, effects to breathing,
interference with or alteration of vocalization, avoidance, and flight.
Changes in dive behavior can vary widely, and may consist of
increased or decreased dive times and surface intervals as well as
changes in the rates of ascent and descent during a dive (e.g., Frankel
and Clark, 2000; Ng and Leung, 2003; Nowacek et al.; 2004; Goldbogen et
al., 2013a, b). Variations in dive behavior may reflect interruptions
in biologically significant activities (e.g., foraging) or they may be
of little biological significance. The impact of an alteration to dive
behavior resulting from an acoustic exposure depends on what the animal
is doing at the time of the exposure and the type and magnitude of the
response.
Disruption of feeding behavior can be difficult to correlate with
anthropogenic sound exposure, so it is usually inferred by observed
displacement from known foraging areas, the appearance of secondary
indicators (e.g., bubble nets or sediment plumes), or changes in dive
behavior. As for other types of behavioral response, the frequency,
duration, and temporal pattern of signal presentation, as well as
differences in species sensitivity, are likely contributing factors to
differences in response in any given circumstance (e.g., Croll et al.,
2001; Nowacek et al.; 2004; Madsen et al., 2006; Yazvenko et al.,
2007). A determination of whether foraging disruptions incur fitness
consequences would require information on or estimates of the energetic
requirements of the affected individuals and the relationship between
prey availability, foraging effort and success, and the life history
stage of the animal.
Visual tracking, passive acoustic monitoring, and movement
recording tags were used to quantify sperm whale behavior prior to,
during, and following exposure to airgun arrays at received levels in
the range 140-160 dB at distances of 7-13 km, following a phase-in of
sound intensity and full array exposures at 1-13 km (Madsen et al.,
2006; Miller et al., 2009). Sperm whales did not exhibit horizontal
avoidance behavior at the surface. However, foraging behavior may have
been affected. The sperm whales exhibited 19 percent less vocal (buzz)
rate during full exposure relative to post exposure, and the whale that
was approached most closely had an extended resting period and did not
resume foraging until the airguns had ceased firing. The remaining
whales continued to execute foraging dives throughout exposure;
however, swimming movements during foraging dives were 6 percent lower
during exposure than control periods (Miller et al., 2009). These data
raise concerns that seismic surveys may impact foraging behavior in
sperm whales, although more data are required to understand whether the
differences were due to exposure or natural variation in sperm whale
behavior (Miller et al., 2009).
Variations in respiration naturally vary with different behaviors
and alterations to breathing rate as a function of acoustic exposure
can be expected to co-occur with other behavioral reactions, such as a
flight response or an alteration in diving. However, respiration rates
in and of themselves may be representative of annoyance or an acute
stress response. Various studies have shown that respiration rates may
either be unaffected or could increase, depending on the species and
signal characteristics, again highlighting the importance in
understanding species differences in the tolerance of underwater noise
when determining the potential for impacts resulting from anthropogenic
sound exposure (e.g., Kastelein et al., 2001, 2005, 2006; Gailey et
al., 2007; Gailey et al., 2016).
Marine mammals vocalize for different purposes and across multiple
modes, such as whistling, echolocation click production, calling, and
singing. Changes in vocalization behavior in response to anthropogenic
noise can occur for any of these modes and may result from a need to
compete with an increase in background noise or may reflect increased
vigilance or a startle response. For example, in the presence of
potentially masking signals, humpback whales and killer whales have
been observed to increase the length of their songs (Miller et al.,
2000; Fristrup et al., 2003; Foote et al., 2004), while right whales
have been observed to shift the frequency content of their calls upward
while reducing the rate of calling in areas of increased anthropogenic
noise (Parks et al., 2007). In some cases, animals may cease sound
production during production of aversive signals (Bowles et al., 1994).
Cerchio et al. (2014) used passive acoustic monitoring to document
the presence of singing humpback whales off the coast of northern
Angola and to opportunistically test for the effect of seismic survey
activity on the number of singing whales. Two recording units were
deployed between March and December 2008 in the offshore environment;
numbers of singers were counted every hour. Generalized Additive Mixed
Models were used to assess the effect of survey day (seasonality), hour
(diel variation), moon phase, and received levels of noise (measured
from a single pulse during each ten minute sampled period) on singer
number. The number of singers significantly decreased with increasing
received level of noise, suggesting that humpback whale breeding
activity was disrupted to some extent by the survey activity.
Castellote et al. (2012) reported acoustic and behavioral changes
by fin whales in response to shipping and airgun noise. Acoustic
features of fin whale song notes recorded in the Mediterranean Sea and
northeast Atlantic Ocean were compared for areas with different
shipping noise levels and traffic intensities and during a seismic
airgun survey. During the first 72 h of the survey, a steady decrease
in song received levels and bearings to singers indicated that whales
moved away from the acoustic source and out of the study area. This
displacement persisted for a time period well beyond the 10-day
duration of seismic airgun activity, providing evidence that fin whales
may avoid an area for an extended period in the presence of increased
noise. The authors hypothesize that fin whale acoustic communication is
modified to compensate for increased background noise and that a
sensitization process may play a role in the observed temporary
displacement.
Seismic pulses at average received levels of 131 dB re 1
[micro]Pa\2\-s caused blue whales to increase call production (Di Iorio
and Clark, 2010). In contrast, McDonald et al. (1995) tracked a blue
whale with seafloor seismometers and reported that it stopped
vocalizing and changed its travel direction at a range of 10 km from
the acoustic source vessel (estimated received level 143 dB pk-pk).
Blackwell et al. (2013) found that bowhead whale call rates dropped
[[Page 30502]]
significantly at onset of airgun use at sites with a median distance of
41-45 km from the survey. Blackwell et al. (2015) expanded this
analysis to show that whales actually increased calling rates as soon
as airgun signals were detectable before ultimately decreasing calling
rates at higher received levels (i.e., 10-minute SELcum of
~127 dB). Overall, these results suggest that bowhead whales may adjust
their vocal output in an effort to compensate for noise before ceasing
vocalization effort and ultimately deflecting from the acoustic source
(Blackwell et al., 2013, 2015). These studies demonstrate that even low
levels of noise received far from the source can induce changes in
vocalization and/or behavior for mysticetes.
Avoidance is the displacement of an individual from an area or
migration path as a result of the presence of a sound or other
stressors, and is one of the most obvious manifestations of disturbance
in marine mammals (Richardson et al., 1995). For example, gray whales
are known to change direction--deflecting from customary migratory
paths--in order to avoid noise from seismic surveys (Malme et al.,
1984). Humpback whales showed avoidance behavior in the presence of an
active seismic array during observational studies and controlled
exposure experiments in western Australia (McCauley et al., 2000).
Avoidance may be short-term, with animals returning to the area once
the noise has ceased (e.g., Bowles et al., 1994; Goold, 1996; Stone et
al., 2000; Morton and Symonds, 2002; Gailey et al., 2007). Longer-term
displacement is possible, however, which may lead to changes in
abundance or distribution patterns of the affected species in the
affected region if habituation to the presence of the sound does not
occur (e.g., Bejder et al., 2006; Teilmann et al., 2006).
A flight response is a dramatic change in normal movement to a
directed and rapid movement away from the perceived location of a sound
source. The flight response differs from other avoidance responses in
the intensity of the response (e.g., directed movement, rate of
travel). Relatively little information on flight responses of marine
mammals to anthropogenic signals exist, although observations of flight
responses to the presence of predators have occurred (Connor and
Heithaus, 1996). The result of a flight response could range from
brief, temporary exertion and displacement from the area where the
signal provokes flight to, in extreme cases, marine mammal strandings
(Evans and England, 2001). However, it should be noted that response to
a perceived predator does not necessarily invoke flight (Ford and
Reeves, 2008), and whether individuals are solitary or in groups may
influence the response.
Behavioral disturbance can also impact marine mammals in more
subtle ways. Increased vigilance may result in costs related to
diversion of focus and attention (i.e., when a response consists of
increased vigilance, it may come at the cost of decreased attention to
other critical behaviors such as foraging or resting). These effects
have generally not been demonstrated for marine mammals, but studies
involving fish and terrestrial animals have shown that increased
vigilance may substantially reduce feeding rates (e.g., Beauchamp and
Livoreil, 1997; Fritz et al., 2002; Purser and Radford, 2011). In
addition, chronic disturbance can cause population declines through
reduction of fitness (e.g., decline in body condition) and subsequent
reduction in reproductive success, survival, or both (e.g., Harrington
and Veitch, 1992; Daan et al., 1996; Bradshaw et al., 1998). However,
Ridgway et al. (2006) reported that increased vigilance in bottlenose
dolphins exposed to sound over a five-day period did not cause any
sleep deprivation or stress effects.
Many animals perform vital functions, such as feeding, resting,
traveling, and socializing, on a diel cycle (24-hour cycle). Disruption
of such functions resulting from reactions to stressors such as sound
exposure are more likely to be significant if they last more than one
diel cycle or recur on subsequent days (Southall et al., 2007).
Consequently, a behavioral response lasting less than one day and not
recurring on subsequent days is not considered particularly severe
unless it could directly affect reproduction or survival (Southall et
al., 2007). Note that there is a difference between multi-day
substantive behavioral reactions and multi-day anthropogenic
activities. For example, just because an activity lasts for multiple
days does not necessarily mean that individual animals are either
exposed to activity-related stressors for multiple days or, further,
exposed in a manner resulting in sustained multi-day substantive
behavioral responses.
Stone (2015) reported data from at-sea observations during 1,196
seismic surveys from 1994 to 2010. When large arrays of airguns
(considered to be 500 in\3\ or more) were firing, lateral displacement,
more localized avoidance, or other changes in behavior were evident for
most odontocetes. However, significant responses to large arrays were
found only for the minke whale and fin whale. Behavioral responses
observed included changes in swimming or surfacing behavior, with
indications that cetaceans remained near the water surface at these
times. Cetaceans were recorded as feeding less often when large arrays
were active. Behavioral observations of gray whales during a seismic
survey monitored whale movements and respirations pre-, during and
post-seismic survey (Gailey et al., 2016). Behavioral state and water
depth were the best `natural' predictors of whale movements and
respiration and, after considering natural variation, none of the
response variables were significantly associated with seismic survey or
vessel sounds.
Stress Responses--An animal's perception of a threat may be
sufficient to trigger stress responses consisting of some combination
of behavioral responses, autonomic nervous system responses,
neuroendocrine responses, or immune responses (e.g., Seyle, 1950;
Moberg, 2000). In many cases, an animal's first and sometimes most
economical (in terms of energetic costs) response is behavioral
avoidance of the potential stressor. Autonomic nervous system responses
to stress typically involve changes in heart rate, blood pressure, and
gastrointestinal activity. These responses have a relatively short
duration and may or may not have a significant long-term effect on an
animal's fitness.
Neuroendocrine stress responses often involve the hypothalamus-
pituitary-adrenal system. Virtually all neuroendocrine functions that
are affected by stress--including immune competence, reproduction,
metabolism, and behavior--are regulated by pituitary hormones. Stress-
induced changes in the secretion of pituitary hormones have been
implicated in failed reproduction, altered metabolism, reduced immune
competence, and behavioral disturbance (e.g., Moberg, 1987; Blecha,
2000). Increases in the circulation of glucocorticoids are also equated
with stress (Romano et al., 2004).
The primary distinction between stress (which is adaptive and does
not normally place an animal at risk) and ``distress'' is the cost of
the response. During a stress response, an animal uses glycogen stores
that can be quickly replenished once the stress is alleviated. In such
circumstances, the cost of the stress response would not pose serious
fitness consequences. However, when an animal does not have sufficient
energy reserves to satisfy the energetic costs of a stress response,
energy resources must be diverted from other functions. This state of
distress will last until the animal replenishes its
[[Page 30503]]
energetic reserves sufficiently to restore normal function.
Relationships between these physiological mechanisms, animal
behavior, and the costs of stress responses are well-studied through
controlled experiments and for both laboratory and free-ranging animals
(e.g., Holberton et al., 1996; Hood et al., 1998; Jessop et al., 2003;
Krausman et al., 2004; Lankford et al., 2005). Stress responses due to
exposure to anthropogenic sounds or other stressors and their effects
on marine mammals have also been reviewed (Fair and Becker, 2000;
Romano et al., 2002b) and, more rarely, studied in wild populations
(e.g., Romano et al., 2002a). For example, Rolland et al. (2012) found
that noise reduction from reduced ship traffic in the Bay of Fundy was
associated with decreased stress in North Atlantic right whales. These
and other studies lead to a reasonable expectation that some marine
mammals will experience physiological stress responses upon exposure to
acoustic stressors and that it is possible that some of these would be
classified as ``distress.'' In addition, any animal experiencing TTS
would likely also experience stress responses (NRC, 2003).
Auditory Masking--Sound can disrupt behavior through masking, or
interfering with, an animal's ability to detect, recognize, or
discriminate between acoustic signals of interest (e.g., those used for
intraspecific communication and social interactions, prey detection,
predator avoidance, navigation) (Richardson et al., 1995; Erbe et al.,
2016). Masking occurs when the receipt of a sound is interfered with by
another coincident sound at similar frequencies and at similar or
higher intensity, and may occur whether the sound is natural (e.g.,
snapping shrimp, wind, waves, precipitation) or anthropogenic (e.g.,
shipping, sonar, seismic exploration) in origin. The ability of a noise
source to mask biologically important sounds depends on the
characteristics of both the noise source and the signal of interest
(e.g., signal-to-noise ratio, temporal variability, direction), in
relation to each other and to an animal's hearing abilities (e.g.,
sensitivity, frequency range, critical ratios, frequency
discrimination, directional discrimination, age or TTS hearing loss),
and existing ambient noise and propagation conditions.
Under certain circumstances, marine mammals experiencing
significant masking could also be impaired from maximizing their
performance fitness in survival and reproduction. Therefore, when the
coincident (masking) sound is man-made, it may be considered harassment
when disrupting or altering critical behaviors. It is important to
distinguish TTS and PTS, which persist after the sound exposure, from
masking, which occurs during the sound exposure. Because masking
(without resulting in TS) is not associated with abnormal physiological
function, it is not considered a physiological effect, but rather a
potential behavioral effect.
The frequency range of the potentially masking sound is important
in determining any potential behavioral impacts. For example, low-
frequency signals may have less effect on high-frequency echolocation
sounds produced by odontocetes but are more likely to affect detection
of mysticete communication calls and other potentially important
natural sounds such as those produced by surf and some prey species.
The masking of communication signals by anthropogenic noise may be
considered as a reduction in the communication space of animals (e.g.,
Clark et al., 2009) and may result in energetic or other costs as
animals change their vocalization behavior (e.g., Miller et al., 2000;
Foote et al., 2004; Parks et al., 2007; Di Iorio and Clark, 2009; Holt
et al., 2009). Masking can be reduced in situations where the signal
and noise come from different directions (Richardson et al., 1995),
through amplitude modulation of the signal, or through other
compensatory behaviors (Houser and Moore, 2014). Masking can be tested
directly in captive species (e.g., Erbe, 2008), but in wild populations
it must be either modeled or inferred from evidence of masking
compensation. There are few studies addressing real-world masking
sounds likely to be experienced by marine mammals in the wild (e.g.,
Branstetter et al., 2013).
Masking affects both senders and receivers of acoustic signals and
can potentially have long-term chronic effects on marine mammals at the
population level as well as at the individual level. Low-frequency
ambient sound levels have increased by as much as 20 dB (more than
three times in terms of SPL) in the world's ocean from pre-industrial
periods, with most of the increase from distant commercial shipping
(Hildebrand, 2009). All anthropogenic sound sources, but especially
chronic and lower-frequency signals (e.g., from vessel traffic),
contribute to elevated ambient sound levels, thus intensifying masking.
Masking effects of pulsed sounds (even from large arrays of
airguns) on marine mammal calls and other natural sounds are expected
to be limited, although there are few specific data on this. Because of
the intermittent nature and low duty cycle of seismic pulses, animals
can emit and receive sounds in the relatively quiet intervals between
pulses. However, in exceptional situations, reverberation occurs for
much or all of the interval between pulses (e.g., Simard et al. 2005;
Clark and Gagnon 2006), which could mask calls. Situations with
prolonged strong reverberation are infrequent. However, it is common
for reverberation to cause some lesser degree of elevation of the
background level between airgun pulses (e.g., Gedamke 2011; Guerra et
al. 2011, 2016; Klinck et al. 2012; Guan et al. 2015), and this weaker
reverberation presumably reduces the detection range of calls and other
natural sounds to some degree. Guerra et al. (2016) reported that
ambient noise levels between seismic pulses were elevated as a result
of reverberation at ranges of 50 km from the seismic source. Based on
measurements in deep water of the Southern Ocean, Gedamke (2011)
estimated that the slight elevation of background levels during
intervals between pulses reduced blue and fin whale communication space
by as much as 36-51 percent when a seismic survey was operating 450-
2,800 km away. Based on preliminary modeling, Wittekind et al. (2016)
reported that airgun sounds could reduce the communication range of
blue and fin whales 2000 km from the seismic source. Nieukirk et al.
(2012) and Blackwell et al. (2013) noted the potential for masking
effects from seismic surveys on large whales.
Some baleen and toothed whales are known to continue calling in the
presence of seismic pulses, and their calls usually can be heard
between the pulses (e.g., Nieukirk et al. 2012; Thode et al. 2012;
Br[ouml]ker et al. 2013; Sciacca et al. 2016). As noted above, Cerchio
et al. (2014) suggested that the breeding display of humpback whales
off Angola could be disrupted by seismic sounds, as singing activity
declined with increasing received levels. In addition, some cetaceans
are known to change their calling rates, shift their peak frequencies,
or otherwise modify their vocal behavior in response to airgun sounds
(e.g., Di Iorio and Clark 2010; Castellote et al. 2012; Blackwell et
al. 2013, 2015). The hearing systems of baleen whales are undoubtedly
more sensitive to low-frequency sounds than are the ears of the small
odontocetes that have been studied directly (e.g., MacGillivray et al.
2014). The sounds important to small odontocetes are
[[Page 30504]]
predominantly at much higher frequencies than are the dominant
components of airgun sounds, thus limiting the potential for masking.
In general, masking effects of seismic pulses are expected to be minor,
given the normally intermittent nature of seismic pulses.
Ship Noise
Vessel noise from the Langseth could affect marine animals in the
proposed survey areas. Houghton et al. (2015) proposed that vessel
speed is the most important predictor of received noise levels, and
Putland et al. (2017) also reported reduced sound levels with decreased
vessel speed. Sounds produced by large vessels generally dominate
ambient noise at frequencies from 20 to 300 Hz (Richardson et al.
1995). However, some energy is also produced at higher frequencies
(Hermannsen et al. 2014); low levels of high-frequency sound from
vessels has been shown to elicit responses in harbor porpoise (Dyndo et
al. 2015). Increased levels of ship noise have been shown to affect
foraging by porpoise (Teilmann et al. 2015; Wisniewska et al. 2018);
Wisniewska et al. (2018) suggest that a decrease in foraging success
could have long-term fitness consequences.
Ship noise, through masking, can reduce the effective communication
distance of a marine mammal if the frequency of the sound source is
close to that used by the animal, and if the sound is present for a
significant fraction of time (e.g., Richardson et al. 1995; Clark et
al. 2009; Jensen et al. 2009; Gervaise et al. 2012; Hatch et al. 2012;
Rice et al. 2014; Dunlop 2015; Erbe et al. 2015; Jones et al. 2017;
Putland et al. 2017). In addition to the frequency and duration of the
masking sound, the strength, temporal pattern, and location of the
introduced sound also play a role in the extent of the masking
(Branstetter et al. 2013, 2016; Finneran and Branstetter 2013; Sills et
al. 2017). Branstetter et al. (2013) reported that time-domain metrics
are also important in describing and predicting masking. In order to
compensate for increased ambient noise, some cetaceans are known to
increase the source levels of their calls in the presence of elevated
noise levels from shipping, shift their peak frequencies, or otherwise
change their vocal behavior (e.g., Parks et al. 2011, 2012, 2016a,b;
Castellote et al. 2012; Melc[oacute]n et al. 2012; Azzara et al. 2013;
Tyack and Janik 2013; Lu[iacute]s et al. 2014; Sairanen 2014; Papale et
al. 2015; Bittencourt et al. 2016; Dahlheim and Castellote 2016;
Gospi[cacute] and Picciulin 2016; Gridley et al. 2016; Heiler et al.
2016; Martins et al. 2016; O'Brien et al. 2016; Tenessen and Parks
2016). Harp seals did not increase their call frequencies in
environments with increased low-frequency sounds (Terhune and Bosker
2016). Holt et al. (2015) reported that changes in vocal modifications
can have increased energetic costs for individual marine mammals. A
negative correlation between the presence of some cetacean species and
the number of vessels in an area has been demonstrated by several
studies (e.g., Campana et al. 2015; Culloch et al. 2016).
Baleen whales are thought to be more sensitive to sound at these
low frequencies than are toothed whales (e.g., MacGillivray et al.
2014), possibly causing localized avoidance of the proposed survey area
during seismic operations. Reactions of gray and humpback whales to
vessels have been studied, and there is limited information available
about the reactions of right whales and rorquals (fin, blue, and minke
whales). Reactions of humpback whales to boats are variable, ranging
from approach to avoidance (Payne 1978; Salden 1993). Baker et al.
(1982, 1983) and Baker and Herman (1989) found humpbacks often move
away when vessels are within several kilometers. Humpbacks seem less
likely to react overtly when actively feeding than when resting or
engaged in other activities (Krieger and Wing 1984, 1986). Increased
levels of ship noise have been shown to affect foraging by humpback
whales (Blair et al. 2016). Fin whale sightings in the western
Mediterranean were negatively correlated with the number of vessels in
the area (Campana et al. 2015). Minke whales and gray seals have shown
slight displacement in response to construction-related vessel traffic
(Anderwald et al. 2013).
Many odontocetes show considerable tolerance of vessel traffic,
although they sometimes react at long distances if confined by ice or
shallow water, if previously harassed by vessels, or have had little or
no recent exposure to ships (Richardson et al. 1995). Dolphins of many
species tolerate and sometimes approach vessels (e.g., Anderwald et al.
2013). Some dolphin species approach moving vessels to ride the bow or
stern waves (Williams et al. 1992). Pirotta et al. (2015) noted that
the physical presence of vessels, not just ship noise, disturbed the
foraging activity of bottlenose dolphins. Sightings of striped dolphin,
Risso's dolphin, sperm whale, and Cuvier's beaked whale in the western
Mediterranean were negatively correlated with the number of vessels in
the area (Campana et al. 2015).
There are few data on the behavioral reactions of beaked whales to
vessel noise, though they seem to avoid approaching vessels (e.g.,
W[uuml]rsig et al. 1998) or dive for an extended period when approached
by a vessel (e.g., Kasuya 1986). Based on a single observation, Aguilar
Soto et al. (2006) suggest foraging efficiency of Cuvier's beaked
whales may be reduced by close approach of vessels.
In summary, project vessel sounds would not be at levels expected
to cause anything more than possible localized and temporary behavioral
changes in marine mammals, and would not be expected to result in
significant negative effects on individuals or at the population level.
In addition, in all oceans of the world, large vessel traffic is
currently so prevalent that it is commonly considered a usual source of
ambient sound (NSF-USGS 2011).
Ship Strike
Vessel collisions with marine mammals, or ship strikes, can result
in death or serious injury of the animal. Wounds resulting from ship
strike may include massive trauma, hemorrhaging, broken bones, or
propeller lacerations (Knowlton and Kraus, 2001). An animal at the
surface may be struck directly by a vessel, a surfacing animal may hit
the bottom of a vessel, or an animal just below the surface may be cut
by a vessel's propeller. Superficial strikes may not kill or result in
the death of the animal. These interactions are typically associated
with large whales (e.g., fin whales), which are occasionally found
draped across the bulbous bow of large commercial ships upon arrival in
port. Although smaller cetaceans are more maneuverable in relation to
large vessels than are large whales, they may also be susceptible to
strike. The severity of injuries typically depends on the size and
speed of the vessel, with the probability of death or serious injury
increasing as vessel speed increases (Knowlton and Kraus, 2001; Laist
et al., 2001; Vanderlaan and Taggart, 2007; Conn and Silber, 2013).
Impact forces increase with speed, as does the probability of a strike
at a given distance (Silber et al., 2010; Gende et al., 2011).
Pace and Silber (2005) also found that the probability of death or
serious injury increased rapidly with increasing vessel speed.
Specifically, the predicted probability of serious injury or death
increased from 45 to 75 percent as vessel speed increased from 10 to 14
kn, and exceeded 90 percent at 17 kn. Higher speeds during collisions
result in greater force of impact, but higher speeds also appear to
increase the chance of severe injuries or death
[[Page 30505]]
through increased likelihood of collision by pulling whales toward the
vessel (Clyne, 1999; Knowlton et al., 1995). In a separate study,
Vanderlaan and Taggart (2007) analyzed the probability of lethal
mortality of large whales at a given speed, showing that the greatest
rate of change in the probability of a lethal injury to a large whale
as a function of vessel speed occurs between 8.6 and 15 kn. The chances
of a lethal injury decline from approximately 80 percent at 15 kn to
approximately 20 percent at 8.6 kn. At speeds below 11.8 kn, the
chances of lethal injury drop below 50 percent, while the probability
asymptotically increases toward one hundred percent above 15 kn.
The Langseth travels at a speed of 4.1 kt (7.6 km/h) while towing
seismic survey gear (LGL 2018). At this speed, both the possibility of
striking a marine mammal and the possibility of a strike resulting in
serious injury or mortality are discountable. At average transit speed,
the probability of serious injury or mortality resulting from a strike
is less than 50 percent. However, the likelihood of a strike actually
happening is again discountable. Ship strikes, as analyzed in the
studies cited above, generally involve commercial shipping, which is
much more common in both space and time than is geophysical survey
activity. Jensen and Silber (2004) summarized ship strikes of large
whales worldwide from 1975-2003 and found that most collisions occurred
in the open ocean and involved large vessels (e.g., commercial
shipping). No such incidents were reported for geophysical survey
vessels during that time period.
It is possible for ship strikes to occur while traveling at slow
speeds. For example, a hydrographic survey vessel traveling at low
speed (5.5 kn) while conducting mapping surveys off the central
California coast struck and killed a blue whale in 2009. The State of
California determined that the whale had suddenly and unexpectedly
surfaced beneath the hull, with the result that the propeller severed
the whale's vertebrae, and that this was an unavoidable event. This
strike represents the only such incident in approximately 540,000 hours
of similar coastal mapping activity (p = 1.9 x 10-\6\; 95%
CI = 0-5.5 x 10-\6\; NMFS, 2013b). In addition, a research
vessel reported a fatal strike in 2011 of a dolphin in the Atlantic,
demonstrating that it is possible for strikes involving smaller
cetaceans to occur. In that case, the incident report indicated that an
animal apparently was struck by the vessel's propeller as it was
intentionally swimming near the vessel. While indicative of the type of
unusual events that cannot be ruled out, neither of these instances
represents a circumstance that would be considered reasonably
foreseeable or that would be considered preventable.
Although the likelihood of the vessel striking a marine mammal is
low, we require a robust ship strike avoidance protocol (see ``Proposed
Mitigation''), which we believe eliminates any foreseeable risk of ship
strike. We anticipate that vessel collisions involving a seismic data
acquisition vessel towing gear, while not impossible, represent
unlikely, unpredictable events for which there are no preventive
measures. Given the required mitigation measures, the relatively slow
speed of the vessel towing gear, the presence of bridge crew watching
for obstacles at all times (including marine mammals), and the presence
of marine mammal observers, we believe that the possibility of ship
strike is discountable and, further, that were a strike of a large
whale to occur, it would be unlikely to result in serious injury or
mortality. No incidental take resulting from ship strike is
anticipated, and this potential effect of the specified activity will
not be discussed further in the following analysis.
Stranding--When a living or dead marine mammal swims or floats onto
shore and becomes ``beached'' or incapable of returning to sea, the
event is a ``stranding'' (Geraci et al., 1999; Perrin and Geraci, 2002;
Geraci and Lounsbury, 2005; NMFS, 2007). The legal definition for a
stranding under the MMPA is that ``(A) a marine mammal is dead and is
(i) on a beach or shore of the United States; or (ii) in waters under
the jurisdiction of the United States (including any navigable waters);
or (B) a marine mammal is alive and is (i) on a beach or shore of the
United States and is unable to return to the water; (ii) on a beach or
shore of the United States and, although able to return to the water,
is in need of apparent medical attention; or (iii) in the waters under
the jurisdiction of the United States (including any navigable waters),
but is unable to return to its natural habitat under its own power or
without assistance.''
Marine mammals strand for a variety of reasons, such as infectious
agents, biotoxicosis, starvation, fishery interaction, ship strike,
unusual oceanographic or weather events, sound exposure, or
combinations of these stressors sustained concurrently or in series.
However, the cause or causes of most strandings are unknown (Geraci et
al., 1976; Eaton, 1979; Odell et al., 1980; Best, 1982). Numerous
studies suggest that the physiology, behavior, habitat relationships,
age, or condition of cetaceans may cause them to strand or might pre-
dispose them to strand when exposed to another phenomenon. These
suggestions are consistent with the conclusions of numerous other
studies that have demonstrated that combinations of dissimilar
stressors commonly combine to kill an animal or dramatically reduce its
fitness, even though one exposure without the other does not produce
the same result (Chroussos, 2000; Creel, 2005; DeVries et al., 2003;
Fair and Becker, 2000; Foley et al., 2001; Moberg, 2000; Relyea, 2005a;
2005b, Romero, 2004; Sih et al., 2004).
Use of military tactical sonar has been implicated in a majority of
investigated stranding events. Most known stranding events have
involved beaked whales, though a small number have involved deep-diving
delphinids or sperm whales (e.g., Mazzariol et al., 2010; Southall et
al., 2013). In general, long duration (~1 second) and high-intensity
sounds (>235 dB SPL) have been implicated in stranding events
(Hildebrand, 2004). With regard to beaked whales, mid-frequency sound
is typically implicated (when causation can be determined) (Hildebrand,
2004). Although seismic airguns create predominantly low-frequency
energy, the signal does include a mid-frequency component. We have
considered the potential for the proposed surveys to result in marine
mammal stranding and have concluded that, based on the best available
information, stranding is not expected to occur.
Effects to Prey--Marine mammal prey varies by species, season, and
location and, for some, is not well documented. Fish react to sounds
which are especially strong and/or intermittent low-frequency sounds.
Short duration, sharp sounds can cause overt or subtle changes in fish
behavior and local distribution. Hastings and Popper (2005) identified
several studies that suggest fish may relocate to avoid certain areas
of sound energy. Additional studies have documented effects of pulsed
sound on fish, although several are based on studies in support of
construction projects (e.g., Scholik and Yan, 2001, 2002; Popper and
Hastings, 2009). Sound pulses at received levels of 160 dB may cause
subtle changes in fish behavior. SPLs of 180 dB may cause noticeable
changes in behavior (Pearson et al., 1992; Skalski et al., 1992). SPLs
of sufficient strength have been known to cause injury to fish and fish
mortality. The most likely impact to fish from survey activities at the
project area would be temporary avoidance of the
[[Page 30506]]
area. 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 anticipated.
Information on seismic airgun impacts to zooplankton, which
represent an important prey type for mysticetes, is limited. However,
McCauley et al. (2017) reported that experimental exposure to a pulse
from a 150 inch\3\ airgun decreased zooplankton abundance when compared
with controls, as measured by sonar and net tows, and caused a two- to
threefold increase in dead adult and larval zooplankton. Although no
adult krill were present, the study found that all larval krill were
killed after air gun passage. Impacts were observed out to the maximum
1.2 km range sampled.
In general, impacts to marine mammal prey are expected to be
limited due to the relatively small temporal and spatial overlap
between the proposed survey and any areas used by marine mammal prey
species. The proposed use of airguns as part of an active seismic array
survey would occur over a relatively short time period (~32 days) at
two locations and would occur over a very small area relative to the
area available as marine mammal habitat in the Pacific Ocean near
Hawaii and the Emperor Seamounts. We believe any impacts to marine
mammals due to adverse affects to their prey would be insignificant due
to the limited spatial and temporal impact of the proposed survey.
However, adverse impacts may occur to a few species of fish and to
zooplankton.
Acoustic Habitat--Acoustic habitat is the soundscape--which
encompasses all of the sound present in a particular location and time,
as a whole--when considered from the perspective of the animals
experiencing it. Animals produce sound for, or listen for sounds
produced by, conspecifics (communication during feeding, mating, and
other social activities), other animals (finding prey or avoiding
predators), and the physical environment (finding suitable habitats,
navigating). Together, sounds made by animals and the geophysical
environment (e.g., produced by earthquakes, lightning, wind, rain,
waves) make up the natural contributions to the total acoustics of a
place. These acoustic conditions, termed acoustic habitat, are one
attribute of an animal's total habitat.
Soundscapes are also defined by, and acoustic habitat influenced
by, the total contribution of anthropogenic sound. This may include
incidental emissions from sources such as vessel traffic, or may be
intentionally introduced to the marine environment for data acquisition
purposes (as in the use of airgun arrays). Anthropogenic noise varies
widely in its frequency content, duration, and loudness and these
characteristics greatly influence the potential habitat-mediated
effects to marine mammals (please see also the previous discussion on
masking under ``Acoustic Effects''), which may range from local effects
for brief periods of time to chronic effects over large areas and for
long durations. Depending on the extent of effects to habitat, animals
may alter their communications signals (thereby potentially expending
additional energy) or miss acoustic cues (either conspecific or
adventitious). For more detail on these concepts see, e.g., Barber et
al., 2010; Pijanowski et al., 2011; Francis and Barber, 2013; Lillis et
al., 2014.
Problems arising from a failure to detect cues are more likely to
occur when noise stimuli are chronic and overlap with biologically
relevant cues used for communication, orientation, and predator/prey
detection (Francis and Barber, 2013). Although the signals emitted by
seismic airgun arrays are generally low frequency, they would also
likely be of short duration and transient in any given area due to the
nature of these surveys. As described previously, exploratory surveys
such as these cover a large area but would be transient rather than
focused in a given location over time and therefore would not be
considered chronic in any given location.
In summary, activities associated with the proposed action are not
likely to have a permanent, adverse effect on any fish habitat or
populations of fish species or on the quality of acoustic habitat.
Thus, any impacts to marine mammal habitat are not expected to cause
significant or long-term consequences for individual marine mammals or
their populations.
Estimated Take
This section provides an estimate of the number of incidental takes
proposed for authorization through this IHA, which will inform both
NMFS' consideration of whether the number of takes is ``small'' 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 would primarily be 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., kogiidae spp.), due to larger predicted
auditory injury zones for those functional hearing groups. The proposed
mitigation and monitoring measures are expected to minimize the
severity of such taking to the extent practicable.
Auditory injury is unlikely to occur for mid-frequency species
given very small modeled zones of injury for those species (13.6 m).
Moreover, the source level of the array is a theoretical definition
assuming a point source and measurement in the far-field of the source
(MacGillivray, 2006). As described by Caldwell and Dragoset (2000), an
array is not a point source, but one that spans a small area. In the
far-field, individual elements in arrays will effectively work as one
source because individual pressure peaks will have coalesced into one
relatively broad pulse. The array can then be considered a ``point
source.'' For distances within the near-field, i.e., approximately 2-3
times the array dimensions, pressure peaks from individual elements do
not arrive simultaneously because the observation point is not
equidistant from each element. The effect is destructive interference
of the outputs of each element, so that peak pressures in the near-
field will be significantly lower than the output of the largest
individual element. Here, the 230 dB 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
230 dB peak SPL 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.
As described previously, no mortality is anticipated or proposed to
be authorized for this activity. Below we describe how the take is
estimated.
Described in the most basic way, 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
[[Page 30507]]
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) and
the number of days of activities. Below, we describe these components
in more detail and present the exposure estimate and associated numbers
of take proposed for authorization.
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 the best available science 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 to fall under Level B
harassment when exposed to underwater anthropogenic noise above
received levels of 160 dB re 1 [mu]Pa (rms) for non-explosive impulsive
(e.g., seismic airguns) sources. L-DEO's proposed activity includes the
use of impulsive seismic sources. Therefore, the 160 dB re 1 [mu]Pa
(rms) criteria is applicable for analysis of level B harassment.
Level A harassment for non-explosive sources--NMFS' Technical
Guidance for Assessing the Effects of Anthropogenic Sound on Marine
Mammal Hearing (NMFS, 2016) 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). The
Technical Guidance identifies the received levels, or thresholds, above
which individual marine mammals are predicted to experience changes in
their hearing sensitivity for all underwater anthropogenic sound
sources, reflects the best available science, and better predicts the
potential for auditory injury than does NMFS' historical criteria.
These thresholds were developed by compiling and synthesizing the
best available science and soliciting input multiple times from both
the public and peer reviewers to inform the final product, and are
provided in Table 2 below. The references, analysis, and methodology
used in the development of the thresholds are described in NMFS 2016
Technical Guidance. As described above, L-DEO's proposed activity
includes the use of intermittent and impulsive seismic sources.
Table 2--Thresholds Identifying the Onset of Permanent Threshold Shift in Marine Mammals
----------------------------------------------------------------------------------------------------------------
PTS onset thresholds
Hearing group ------------------------------------------------------------------------
Impulsive * Non-impulsive
----------------------------------------------------------------------------------------------------------------
Low-Frequency (LF) Cetaceans........... Lpk,flat: 219 dB; LE,LF,24h: 199 dB.
LE,LF,24h: 183 dB.
Mid-Frequency (MF) Cetaceans........... Lpk,flat: 230 dB; LE,MF,24h: 198 dB.
LE,MF,24h: 185 dB.
High-Frequency (HF) Cetaceans.......... Lpk,flat: 202 dB; LE,HF,24h: 173 dB.
LE,HF,24h: 155 dB.
Phocid Pinnipeds (PW) (Underwater)..... Lpk,flat: 218 dB; LE,PW,24h: 201 dB.
LE,PW,24h: 185 dB.
Otariid Pinnipeds (OW) (Underwater).... Lpk,flat: 232 dB; LE,OW,24h: 219 dB.
LE,OW,24h: 203 dB.
----------------------------------------------------------------------------------------------------------------
Note: * Dual metric acoustic thresholds for impulsive sounds: Use whichever results in the largest isopleth for
calculating PTS onset. If a non-impulsive sound has the potential of exceeding the peak sound pressure level
thresholds associated with impulsive sounds, these thresholds should also be considered.
Note: Peak sound pressure (Lpk) has a reference value of 1 [mu]Pa, and cumulative sound exposure level (LE) has
a reference value of 1[mu]Pa2s. 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 estimating the area ensonified above the
relevant acoustic thresholds.
The proposed surveys would acquire data with 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 and 40-in\3\ airgun at a 12-m tow depth in deep water
(>1000 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 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 sound
pressure level (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
[[Page 30508]]
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 GoM
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).
Measurements have not been reported for the single 40-in\3\ airgun.
L-DEO model results are used to determine the 160-dB (rms) radius for
the 40-in\3\ airgun at a 12 m tow depth in deep water (See LGL 2018,
Figure A-2). For intermediate-water depths, a correction factor of 1.5
was applied to the deep-water model results.
L-DEO's modeling methodology is described in greater detail in the
IHA application (LGL 2018). The estimated distances to the Level B
harassment isopleth for the Langseth's 36-airgun array and single 40-
in\3\ airgun are shown in Table 3.
Table 3--Predicted Radial Distances From R/V Langseth Seismic Source to Isopleths Corresponding to Level B
Harassment Threshold
----------------------------------------------------------------------------------------------------------------
Predicted distances
Source and volume Tow depth (m) Water depth (m) (in m) to the 160-dB
received sound level
----------------------------------------------------------------------------------------------------------------
Single Bolt airgun, 40 in\3\.................. 12 >1000 \1\ 431
100-1000 \2\ 647
4 strings, 36 airguns, 6,600 in\3\............ 12 >1000 \1\ 6,733
100-1000 \2\ 10,100
----------------------------------------------------------------------------------------------------------------
\1\ Distance is based on L-DEO model results.
\2\ Distance is based on L-DEO model results with a 1.5 x correction factor between deep and intermediate water
depths.
Predicted distances to Level A harassment isopleths, which vary
based on marine mammal hearing groups, were calculated based on
modeling performed by L-DEO using the NUCLEUS software program and the
NMFS User Spreadsheet, described below. The updated acoustic thresholds
for impulsive sounds (e.g., airguns) contained in the Technical
Guidance were presented as dual metric acoustic thresholds using both
SELcum and peak sound pressure metrics (NMFS 2016). As dual
metrics, NMFS considers onset of PTS (Level A harassment) to have
occurred when either one of the two metrics is exceeded (i.e., metric
resulting in the largest isopleth). The SELcum metric
considers both level and duration of exposure, as well as auditory
weighting functions by marine mammal hearing group. In recognition of
the fact that the requirement to calculate Level A harassment
ensonified areas could be more technically challenging to predict due
to the duration component and the use of weighting functions in the new
SELcum thresholds, NMFS developed an optional User
Spreadsheet that includes tools to help predict a simple isopleth that
can be used in conjunction with marine mammal density or occurrence to
facilitate the estimation of take numbers.
The values for SELcum and peak SPL for the Langseth
airgun array were derived from calculating the modified farfield
signature (Table 4). The farfield signature is often used as a
theoretical representation of the source level. To compute the farfield
signature, the source level is estimated at a large distance 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 farfield 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 farfield signature. The pulses from the
different airguns spread out in time such that the source levels
observed or modeled are the result of the summation of pulses from a
few airguns, not the full array (Tolstoy et al. 2009). At larger
distances, away from the source array center, sound pressure of all the
airguns in the array stack coherently, but not within one time sample,
resulting in smaller source levels (a few dB) than the source level
derived from the farfield signature. Because the farfield signature
does not take into account the large array effect near the source and
is calculated as a point source, the modified farfield 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 Level B harassment 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.
[[Page 30509]]
Table 4--Modeled Source Levels Based on Modified Farfield Signature for the R/V Langseth 6,600 in\3\ Airgun Array, and single 40 in\3\ Airgun
--------------------------------------------------------------------------------------------------------------------------------------------------------
Low frequency Mid frequency High frequency Phocid pinnipeds Otariid pinnipeds
cetaceans cetaceans cetaceans (underwater) (underwater)
(Lpk,flat: 219 dB; (Lpk,flat: 230 dB; (Lpk,flat: 202 dB; (Lpk,flat: 218 dB; (Lpk,flat: 232 dB;
LE,LF,24h: 183 dB) LE,MF,24h: 185 dB LE,HF,24h: 155 dB) LE,HF,24h: 185 dB) LE,HF,24h: 203 dB)
--------------------------------------------------------------------------------------------------------------------------------------------------------
6,600 in\3\ airgun array (Peak SPLflat)............. 252.06 252.65 253.24 252.25 252.52
6,600 in\3\ airgun array (SELcum)................... 232.98 232.83 233.08 232.83 232.07
40 in\3\ airgun (Peak SPLflat)...................... 223.93 N.A. 223.92 223.95 N.A.
40 in\3\ airgun (SELcum)............................ 202.99 202.89 204.37 202.89 202.35
--------------------------------------------------------------------------------------------------------------------------------------------------------
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
hertz (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 source velocities and shot intervals specific to each
of the three planned surveys (Table 1), potential radial distances to
auditory injury zones were then calculated for SELcum
thresholds.
Inputs to the User Spreadsheets in the form of estimated SLs are
shown in Table 5. User Spreadsheets used by L-DEO to estimate distances
to Level A harassment isopleths for the 36-airgun array and single 40
in\3\ airgun for the surveys are shown is Tables A-2, A-3, A-5, and A-8
in Appendix A of the IHA application (LGL 2018). Outputs from the User
Spreadsheets in the form of estimated distances to Level A harassment
isopleths for the surveys 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 (SELcum and Peak
SPLflat) is exceeded (i.e., metric resulting in the largest
isopleth).
Table 5--Modeled Radial Distances (m) to Isopleths Corresponding to Level A Harassment Thresholds
--------------------------------------------------------------------------------------------------------------------------------------------------------
Low frequency Mid frequency High frequency Phocid pinnipeds Otariid pinnipeds
cetaceans cetaceans cetaceans (underwater) (underwater)
(Lpk,flat: 219 dB; (Lpk,flat: 230 dB; (Lpk,flat: 202 dB; (Lpk,flat: 218 dB; (Lpk,flat: 232 dB;
LE,LF,24h: 183 dB) LE,MF,24h: 185 dB LE,HF,24h: 155 dB) LE,HF,24h: 185 dB) LE,HF,24h: 203 dB)
--------------------------------------------------------------------------------------------------------------------------------------------------------
6,600 in\3\ airgun array (Peak SPLflat)............. 38.9 13.6 268.3 43.7 10.6
6,600 in\3\ airgun array (SELcum)................... 320.2 N.A. N.A. N.A. N.A.
40 in\3\ airgun (Peak SPLflat)...................... 1.76 N.A. 12.5 1.98 N.A.
40 in\3\ airgun (SELcum)............................ 2.38 N.A. N.A. N.A. N.A.
--------------------------------------------------------------------------------------------------------------------------------------------------------
Note that because of some of the assumptions included in the
methods used, isopleths produced may be overestimates to some degree,
which will ultimately result in some degree of overestimate 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 proposed 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.
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. The best available scientific information was considered
in conducting marine mammal exposure estimates (the basis for
estimating take).
In the proposed survey area in the Hawaiian EEZ, densities from
Bradford et al. (2017) were used, when available. For the pygmy sperm
whale, dwarf sperm whale, and spinner dolphin, densities from Barlow et
al. (2009) were used because densities were not provided by Bradford et
al. (2017). For the humpback, minke, and killer whales, the calculated
take was increased to mean group size, based on Bradford et al. (2017).
For Hawaiian monk seals, NMFS recommended following the methods used by
the U.S. Navy (Navy 2017a) to determine densities. L-DEO followed a
similar method, but did not correct for hauled out animals as haul-out
sites are not accessible in offshore areas. We determined density by
dividing the number of animals expected to occur in the Hawaiian EEZ in
water depths >200 m. According to the U.S. Navy (Navy 2017a), 90
percent of the population may be found within the 200-m isobath;
therefore 10 percent of the population (127 of 1272 animals; Carretta
et al. 2017) is expected to occur outside of the 200-m isobath. The
area within the Hawaii EEZ but outside of the 200-m isobath was
estimated by the U.S. Navy to be 2,461,994 km\2\ (Navy 2017a). Thus, we
estimated the average density of monk seals at sea where they could be
[[Page 30510]]
exposed to seismic sounds as 127/2,461,994 km\2\ = 0.0000517/km\2\. No
haul-out factors were used to adjust this density, as it is not
possible that animals would haul out beyond the 200-m isobath.
Densities for the Hawaii portion of the survey are shown in Table 7.
There are very few published data on the densities of cetaceans or
pinnipeds in the Emperor Seamounts area, so NMFS relied on a range of
sources to establish marine mammal densities. As part of the Navy's
Final Supplemental Environmental Impact Statement/Supplemental Overseas
Environmental Impact Statement for SURTASS LFA Sonar Routine Training,
Testing, and Military Operations, the Navy modelled densities for a
designated mission area northeast of Japan during the summer season.
These values were used for the North Pacific right whale, sei whale,
fin whale, sperm whale, Cuvier's beaked whale, Stejneger's beaked
whale, and Baird's beaked whale.
For northern right whale dolphin, Dall's porpoise, and northern fur
seal, L-DEO used densities from Buckland et al. (1993). Forney and Wade
(2006) reported a density of 0.3/100 km\2\ for killer whales at
latitudes 43-48[deg] N where the proposed survey would be conducted.
Although Miyashita (1993) published data on the abundance of striped,
Pantropical spotted, bottlenose, and Risso's dolphins, and false killer
and short-finned pilot whales in the Northwest Pacific Ocean as far
north as 41[deg] N, the distributional range of the Pantropical spotted
and bottlenose dolphins does not extend as far north as the proposed
survey area. For the other species, we used data from 40-41[deg] N,
160-180[deg] E to calculate densities and estimate the numbers of
individuals that could be exposed to seismic sounds during the proposed
survey. Risso's dolphin, false killer whale, and short-finned pilot
whale are expected to be rare in the proposed survey area, and the
calculated densities were zero. Thus, we used the mean group size from
Bradford et al. (2017) for Risso's dolphin and short-finned pilot
whale, and the mean group size of false killer whales from Barlow
(2006).
The short-beaked common dolphin is expected to be rare in the
Emperor Seamounts survey area; thus, there are no density estimates
available. L-DEO used the mean group size (rounded up) for the
California Current from Barlow (2016). The density of Bryde's whale in
the proposed survey area was assumed to be zero, based on information
from Hakamada et al. (2009, 2017) and Forney et al. (2015); its known
distribution range does not appear to extend that far north. For this
species, L-DEO rounded up the mean group size from Bradford et al.
(2017). For pygmy and dwarf sperm whales NMFS assumed densities in the
Emperor Seamounts would be equivalent to those in the Hawaii survey are
and used densities from Bradford et al. 2017.
The densities for the remaining species were obtained from
calculations using data from the papers presented to the IWC. For blue
and humpback whales, L-DEO used a weighted mean density from Matsuoka
et al. (2009) for the years 1994-2007 and Hakamada and Matsuoka (2015)
for the years 2008-2014. L-DEO used Matsuoka et al. (2009) instead of
Matsuoka et al. (2015), as the later document did not contain all of
the necessary information to calculate densities. L-DEO used densities
for their Block 9N which coincides with the proposed Emperor Seamounts
survey area. The density for each survey period was weighted by the
number of years in the survey period; that is, 14 years for Matsuoka et
al. (2009) and 7 years for Hakamada and Matsuoka (2015), to obtain a
final density for the 21-year period. For minke whales L-DEO used the
estimates of numbers of whales in survey blocks overlapping the Emperor
Seamounts survey area from Hakamada et al. (2009); densities were
estimated by dividing the number of whales in Block 9N by the area of
Block 9N. For gray whales, NMFS used a paper by Rugh et al. (2005) that
looked at abundance of eastern DPS gray whales. The paper provides mean
group sizes for their surveys, which ranged from 1 to 2 individuals.
For purposes of estimating exposures we will assume that the western
DPS group sizes would not vary greatly from the eastern DPS. As such,
NMFS assumes that there will be two western DPS gray whales Level B
takes, based on mean group size.
Finally, no northern elephant seals have been reported during any
of the above surveys although Buckland et al. (1993) estimated fur seal
abundance during their surveys. Telemetry studies, however, indicate
that elephant seals do forage as far west as the proposed Emperor
Seamounts survey area. Here, L-DEO assumed a density of 0.00831/1000
km\2\, which is 10 percent of that used by LGL Limited (2017) for an
area off the west coast of the United States. However, densities of
northern elephant seals in the region are expected to be much less than
densities of northern fur seals. For species that are unlikely to occur
in the survey area, such as ribbon seals, proposed exposures are set at
5 individuals. Densities for Emperor are shown in Table 8.
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 harassment 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 harassment and Level
B harassment thresholds. The area estimated to be ensonified in a
single day of the survey is then calculated (Table 6), 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. Active seismic operations are planned for 13
days at Emperor Seamounts and 19 days at Hawaii.
Table 6--Areas (km\2\) Estimated To Be Ensonified to Level A and Level B Harassment Thresholds, per Day for Hawaii and Emperor Seamounts Surveys
--------------------------------------------------------------------------------------------------------------------------------------------------------
Daily Total
Survey Criteria ensonified Total survey 25% increase ensonified Relevant
area (km \2\) days area (km \2\) isopleth (m)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Hawaii Level B
--------------------------------------------------------------------------------------------------------------------------------------------------------
Multi-depth line (intermediate water)... 160 dB........................ 538.5 12 1.25 8076.9 10,100
Multi-depth line (deep water)........... 160 dB........................ 2349.8 12 1.25 35246.4 6,733
[[Page 30511]]
Multi-depth line (total)................ 160 dB........................ 2888.2 12 1.25 43323.3 6,733
Deep-water line......................... 160 dB........................ 2566.3 7 1.25 22455.1 6,733
--------------------------------------------------------------------------------------------------------------------------------------------------------
Hawaii Level A \1\
--------------------------------------------------------------------------------------------------------------------------------------------------------
Hawaii.................................. LF Cetacean................... 115.6 19 1.25 2745.4 320.2
MF Cetacean................... 4.9 19 1.25 116.3 13.6
HF Cetacean................... 96.8 19 1.25 2299.3 268.3
Phocid........................ 15.7 19 1.25 373.8 43.7
--------------------------------------------------------------------------------------------------------------------------------------------------------
Emperor Seamounts Level B
--------------------------------------------------------------------------------------------------------------------------------------------------------
Emperor Seamounts....................... 160 dB........................ 2566.3 13 1.25 41702.4 6,733
--------------------------------------------------------------------------------------------------------------------------------------------------------
Emperor Seamounts Level A \1\
--------------------------------------------------------------------------------------------------------------------------------------------------------
Emperor Seamounts....................... LF Cetacean................... 115.6 13 1.25 1878.4 320.2
--------------------------------------------------------------------------------------------------------------------------------------------------------
MF Cetacean................... 4.9 13 1.25 79.6 13.6
HF Cetacean................... 96.8 13 1.25 1573.2 268.3
Phocid........................ 15.7 13 1.25 255.7 43.7
Otariid....................... 3.8 13 1.25 62 10.6
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ Level A ensonified areas are estimated based on the greater of the distances calculated to Level A isopleths using dual criteria (SELcum and
peakSPL).
The product is then multiplied by 1.25 to account for the
additional 25 percent contingency. This results in an estimate of the
total areas (km\2\) expected to be ensonified to the Level A harassment
and Level B harassment thresholds. For purposes of Level B take
calculations, areas estimated to be ensonified to Level A harassment
thresholds are subtracted from total areas estimated to be ensonified
to Level B harassment thresholds in order to avoid double counting the
animals taken (i.e., if an animal is taken by Level A harassment, it is
not also counted as taken by Level B harassment). The marine mammals
predicted to occur within these respective areas, based on estimated
densities, are assumed to be incidentally taken.
Estimated exposures for the Hawaii survey and the Emperor Seamounts
survey are shown respectively in Table 7 and Table 8.
Table 7--Densities, Estimated Level A and Level B Exposures, and Percentage of Stock or Population Exposed During Hawaii Survey
--------------------------------------------------------------------------------------------------------------------------------------------------------
Takes proposed for
Density (#/ Total Percentage authorization
Species Stock 1000 km\2\ ) exposures Level A Level B of stock/ -------------------------
population Level A Level B
--------------------------------------------------------------------------------------------------------------------------------------------------------
Mysticetes:
Humpback Whale................. Central North Pacific .............. \4\ 2 ........... 2 <0.01 0 2
Western North Pacific .............. ........... 0.2 ........... ........... ........... ...........
Minke whale.................... Hawaii............... \3\ 0 \4\ 1 0 0 <0.01 0 1
Bryde's whale.................. Hawaii............... \1\ 0.72 49 2 47 2.8 2 47
Sei whale...................... Hawaii............... \1\ 0.16 11 0 11 6.2 0 11
Fin whale...................... Hawaii............... \1\ 0.06 4 0 4 2.7 0 4
Blue whale..................... Central north Pacific \1\ 0.05 5 0 5 3.9 0 5
Odontocetes:
Sperm whale.................... Hawaii............... \1\ 1.86 122 0 122 2.7 0 122
Pygmy sperm whale.............. Hawaii............... \2\ 2.91 198 7 191 2.8 7 191
Dwarf sperm whale.............. Hawaii............... \2\ 7.14 486 16 470 2.8 16 470
Cuvier's beaked whale.......... Hawaii pelagic....... \1\ 0.30 20 0 20 2.7 0 20
Longman's beaked whale......... Hawaii............... \1\ 3.11 205 0 205 2.7 0 205
Blainville's beaked whale...... Hawaii pelagic....... \1\ 0.86 57 0 57 2.7 0 57
Ginkgo-toothed beaked whale.... N/A.................. \6\ 0.63 41 0 41 0.16 0 41
Deraniygala's beaked whale..... N/A.................. \6\ 0.63 41 0 41 0.16 0 41
Hubb's beaked whale............ N/A.................. \6\ 0.63 41 0 41 0.16 0 41
Rough-toothed dolphin.......... Hawaii............... \1\ 29.63 1,952 3 1,949 2.7 0 1,952
Common bottlenose dolphin...... HI Pelagic........... \1\ 8.99 592 1 591 \7\ 2.7 0 592
Oahu................. 0.4 ........... ........... ........... ........... ........... ...........
4 islands............ 1.5 ........... ........... ........... ........... ........... ...........
HI Islands........... 2.3 ........... ........... ........... ........... ........... ...........
Pantropical spotted dolphin.... HI Pelagic........... \1\ 23.32 1,534 3 1531 \8\ 1.3 0 1,354
[[Page 30512]]
Oahu................. N.A. ........... ........... ........... ........... ........... ...........
4 island............. N.A. ........... ........... ........... ........... ........... ...........
HI Islands........... N.A. ........... ........... ........... ........... ........... ...........
Spinner dolphin................ HI Pelagic........... \2\ 6.99 461 1 460 N.A. 0 461
HI Island............ .............. ........... ........... ........... \9\ 10.9 ........... ...........
Oahu/4 island........ .............. ........... ........... ........... 19.4 ........... ...........
Striped dolphin................ HI Pelagic........... \1\ 5.36 354 1 353 0.6 0 354
Fraser's dolphin............... Hawaii............... \1\ 21.0 1,383 2 1381 2.7 0 1,383
Risso's dolphin................ Hawaii............... \1\ 4.74 313 1 312 2.7 0 313
Melon-headed whale............. HI Islands........... \1\ 3.54 233 0 233 \10\ 2.4 0 233
Kohala resident...... .............. ........... ........... ........... 5.2 ........... ...........
Pygmy killer whale............. Hawaii............... \1\ 4.35 287 1 286 2.7 0 287
False killer whale............. MHI Insular.......... \5\ 0.0.09 6 0 6 3.5 0 6
HI Pelagic........... \5\ 0.06 4 0 4 0.26 0 4
Killer whale................... Hawaiian Islands..... \1\ 0.06 \4\ 5 0 4 2.7 0 5
Short-finned pilot whale....... Hawaii............... \1\ 7.97 525 1 524 2.7 0 525
Pinnipeds:
Hawaiian monk seal............. Hawaii............... \3\ 0.051 3 0 3 0.15 0 3
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ Bradford et al. 2017.
\2\ Barlow et al. 2009.
\3\ U.S. Department of the Navy. (2017a). U.S. Navy Marine Species Density Database Phase III for the Hawaii-Southern California Training and Testing
Study Area. NAVFAC Pacific Technical Report. Naval Facilities Engineering Command Pacific, Pearl Harbor, HI. 274 pp. Navy, 2017.
\4\ Requested take authorization (Level B only) increased to mean group size from Bradford et al., 2017.
\5\ Bradford et al. 2015.
\6\ From Bradford et al. (2017) for `Unidentified Mesoplodon' proportioned equally among Mesoplodon spp., except M. densirostris.
\7\ Assumes 98.5 percent of proposed takes are from Hawaii pelagic stock (583) with remaining 9 animals split evenly among Oahu, 4 Islands, and Hawaiian
Islands stock.
\8\ Assumes 50 percent of proposed takes are from Hawaii pelagic stock (767) since most sightings occur in waters between 1,500 -5,000 m. The remainder
are split evenly (256) between Hawaiian Islands, 4 islands, and Oahu stocks. Populations of insular stocks are unknown.
\9\ Assumes 70 percent of proposed takes from Hawaii pelagic stock (323) since most of the survey tracklines will occur outside of boundary ranges of
Hawaii Island and Oahu/4 island stocks. Assumes remaining takes (138) are split evenly between Hawaii Island (69) and Oahu/4 island (69) stocks.
\10\ Assumes 90 percent of takes from Hawaiian Islands stock (210) and 10 percent from Kohala resident stock which has a small range.
Table 8--Densities, Estimated Level A and Level B Exposures, Percentage of Stock or Population Exposed, and Number of Takes Proposed for Authorization
During Emperor Seamounts Survey
--------------------------------------------------------------------------------------------------------------------------------------------------------
Takes proposed for
Estimated Total Level A Level B % of Pop. authorization
Species Stock density (#/ exposures takes takes (total -------------------------
1000 km \2\) takes) Level A Level B
--------------------------------------------------------------------------------------------------------------------------------------------------------
Mysticetes.........................
Gray whale......................... N/A.................. N.A. \2\ 2 0 2 1.43 0 2
North Pacific right whale.......... N/A/................. \1\ 0.01 \10\ 2 0 0 0.44 0 2
Humpback whale..................... Central North Pacific \1\ 0.41 16 1 15 \11\ 0.16 1 16
Western North Pacific 2 0 2 \11\ 0.18 0 2
DPS.
Minke whale........................ N/A.................. 2.48 108 5 103 0.49 5 108
Bryde's whale...................... N/A.................. N.A. \3\ 2 N.A. N.A. <0.01 0 2
Sei whale.......................... N/A.................. \1\ 0.29 13 1 12 0.05 1 12
Fin whale.......................... N/A.................. \1\ 0.20 9 0 8 0.06 0 8
Blue whale......................... Central north Pacific 0.13 5 0 5 3.7 0 5
Odontocetes:
Sperm whale.................... N/A.................. \1\ 2.20 92 0 92 0.31 0 92
Pygmy sperm whale.............. N/A.................. \4\ 2.91 126 5 121 1.76 5 121
Dwarf sperm whale.............. N/A.................. \4\ 7.14 309 11 298 1.76 11 298
Cuvier's beaked whale.......... N/A.................. \1\ 5.40 225 0 225 1.13 0 225
Stejner's beaked whale......... Alaska............... \1\ 0.5 21 0 21 0.08 0 21
Baird's beaked whale........... N/A.................. \1\ 2.9 121 0 121 1.19 0 121
Short-beaked common dolphin.... N/A.................. \5\ 180 N.A. N.A. N.A. <0.01 0 180
Striped dolphin................ N/A.................. \6\ 9.21 385 1 384 0.04 0 385
Pacific white-sided dolphin.... N/A.................. \7\ 68.81 2,875 5 2,870 0.29 0 2,875
Northern right whale dolphin... N/A.................. \7\ 3.37 141 0 141 0.05 0 141
Risso's dolphin................ N/A.................. \3\ 27 1,128 2 1,126 1.02 0 1,128
False killer whale............. N/A.................. \5\ 10 418 1 417 2.51 0 418
Killer whale................... N/A.................. \8\ 3.00 125 0 125 1.47 0 125
Short-finned pilot whale....... N/A.................. \3\ 41 1,713 3 1,710 3.2 0 1,713
Dall's porpoise................ N/A.................. 35.46 1,535 56 1,479 0.13 56 1,479
Pinnipeds:
Northern fur seal.............. N/A.................. \7\ 3.56 149 0 148 0.01 0 148
Northern elephant seal......... N/A.................. 8.31 349 2 347 0.16 2 347
Ribbon seal.................... Alaska............... N.A. \9\ 5 0 5 <0.01 0 5
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ Navy 2017b. Final Supplemental Environmental Impact Statement/Supplemental Overseas Environmental Impact Statement.
[[Page 30513]]
\2\ Mean group size based on Rugh et al. (2005).
\3\ Mean group size from Bradford et al. (2017).
\4\ Bradford et al. (2017).
\5\ Mean group size from Barlow (2016).
\6\ Miyashita (1993).
\7\ Buckland et al. (1993).
\8\ Forney and Wade (2006).
\9\ Estimated exposures increased to 5 for pinnipeds.
\10\ Mean group size from Matsuoka et al. (2009).
\11\ Based on population size, take is split proportionally between central north Pacific (91.2 percent of total take) and western north Pacific DPS
stocks (9.8 percent of total take).
Estimated exposures are tabulated in Table 7 and Table 8. The sum
will be the total number of takes proposed for authorization. Table 7
and Table 8 contain the numbers of animals proposed for authorized
take.
It should be noted that the proposed take numbers shown in Tables 7
and 8 are expected to be conservative for several reasons. First, in
the calculations of estimated take, 25 percent has been added in the
form of operational survey days 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, and
in recognition of the uncertainties in the density estimates used to
estimate take as described above. Additionally, marine mammals would be
expected to move away from a loud sound source that represents an
aversive stimulus, such as an airgun array, potentially reducing the
number of Level A takes. However, the extent to which marine mammals
would move away from the sound source is difficult to quantify and is,
therefore, not accounted for in the take estimates.
Note that for some marine mammal species, we propose to authorize a
different number of incidental takes than the number of incidental
takes requested by L-DEO (see Table 5 and Table 6 in the IHA
application for requested take numbers).
Proposed 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 such
activity, ``and other means of effecting the least practicable impact
on such species or stock and its habitat, paying particular attention
to rookeries, mating grounds, and areas of similar significance, and on
the availability of such species or stock for 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 such
activity or other means of effecting the least practicable adverse
impact upon the affected species or stocks and their habitat (50 CFR
216.104(a)(11)).
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, 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,.
L-DEO 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 proposed mitigation measures
into their project description based on the above sources.
To reduce the potential for disturbance from acoustic stimuli
associated with the activities, L-DEO has proposed to implement
mitigation measures for marine mammals. Mitigation measures that would
be adopted during the proposed surveys include (1) Vessel-based visual
mitigation monitoring; (2) Vessel-based passive acoustic monitoring;
(3) Establishment of an exclusion zone; (4) Power down procedures; (5)
Shutdown procedures; (6) Ramp-up procedures; and (7) Vessel strike
avoidance measures.
Vessel-Based Visual Mitigation Monitoring
Visual monitoring requires the use of trained observers (herein
referred to as visual PSOs) to scan the ocean surface visually for the
presence of marine mammals. The area to be scanned visually includes
primarily the exclusion zone, but also the buffer zone. The buffer zone
means an area beyond the exclusion zone to be monitored for the
presence of marine mammals that may enter the exclusion zone. During
pre-clearance monitoring (i.e., before ramp-up begins), the buffer zone
also acts as an extension of the exclusion zone 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 meter
exclusion zone, out to a radius of 1,000 meters from the edges of the
airgun array (500-1,000 meters). Visual monitoring of the exclusion
zones 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 close to the vessel. Visual monitoring
of the buffer zone is intended to (1) provide additional protection to
na[iuml]ve marine mammals that may be in the area during pre-clearance,
and (2) during airgun use, aid in establishing and maintaining the
exclusion zone by alerting the visual observer and crew of marine
mammals that are outside of, but may approach and enter, the exclusion
zone.
L-DEO must use at least five dedicated, trained, NMFS-approved
Protected Species Observers (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 aboard the
vessel must have a minimum of 90 days at-sea
[[Page 30514]]
experience working in those roles, respectively, during a deep
penetration (i.e., ``high energy'') seismic survey, with no more than
18 months elapsed since the conclusion of the at-sea experience. One
visual PSO with such experience shall be designated as the lead for the
entire protected species observation team. The lead PSO shall serve as
primary point of contact for the vessel operator and ensure all PSO
requirements per the IHA are met. To the maximum extent practicable,
the experienced PSOs should be scheduled to be on duty with those PSOs
with appropriate training but who have not yet gained relevant
experience.
During survey operations (e.g., any day on which use of the
acoustic source is planned to occur, and whenever the acoustic source
is in the water, whether activated or not), a minimum of two visual
PSOs must be on duty and conducting visual observations at all times
during daylight hours (i.e., from 30 minutes prior to sunrise through
30 minutes following sunset) and 30 minutes prior to and during
nighttime ramp-ups of the airgun array. Visual monitoring of the
exclusion and buffer zones must begin no less than 30 minutes prior to
ramp-up and must continue until one hour after use of the acoustic
source ceases or until 30 minutes past sunset. Visual PSOs shall
coordinate to ensure 360[deg] visual coverage around the vessel from
the most appropriate observation posts, and shall conduct visual
observations using binoculars and the naked eye while free from
distractions and in a consistent, systematic, and diligent manner. PSOs
shall establish and monitor the exclusion and buffer zones. These zones
shall be based upon the radial distance from the edges of the acoustic
source (rather than being based on the center of the array or around
the vessel itself). During use of the acoustic source (i.e., anytime
airguns are active, including ramp-up), occurrences of marine mammals
within the buffer zone (but outside the exclusion zone) shall be
communicated to the operator to prepare for the potential shutdown or
powerdown of the acoustic source.
During use of the airgun (i.e., anytime the acoustic source is
active, including ramp-up), occurrences of marine mammals within the
buffer zone (but outside the exclusion zone) should be communicated to
the operator to prepare for the potential shutdown or powerdown of the
acoustic source. Visual PSOs will immediately communicate all
observations to the on duty acoustic PSO(s), including any
determination by the PSO regarding species identification, distance,
and bearing and the degree of confidence in the determination. Any
observations of marine mammals by crew members shall be relayed to the
PSO team. During good conditions (e.g., daylight hours; Beaufort sea
state (BSS) 3 or less), visual PSOs shall conduct observations when the
acoustic source is not operating for comparison of sighting rates and
behavior with and without use of the acoustic source and between
acquisition periods, to the maximum extent practicable. Visual PSOs may
be on watch for a maximum of two 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
daylight hours) in maintaining an exclusion zone 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.
Passive acoustic monitoring (PAM) would take place in addition to
the visual monitoring program. Visual monitoring typically is not
effective during periods of poor visibility or at night, and even with
good visibility, is unable to detect marine mammals when they are below
the surface or beyond visual range. Acoustical 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 call, but it can be
effective either by day or by night, and does not depend on good
visibility. It would be monitored in real time so that the visual
observers can be advised when cetaceans are detected.
The R/V Langseth will use a towed PAM system, which must be
monitored by at a minimum one on duty acoustic PSO beginning at least
30 minutes prior to ramp-up and at all times during use of the acoustic
source. Acoustic PSOs may be on watch for a maximum of four 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 two hours
without acoustic monitoring during daylight hours only under the
following conditions:
Sea state is less than or equal to BSS 4;
No marine mammals (excluding delphinids) detected solely
by PAM in the applicable exclusion zone in the previous two hours;
NMFS is notified via email as soon as practicable with the
time and location in which operations began occurring without an active
PAM system; and
Operations with an active acoustic source, but without an
operating PAM system, do not exceed a cumulative total of four hours in
any 24-hour period.
Establishment of an Exclusion Zone and Buffer Zone
An exclusion zone (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 would establish a minimum EZ with a 500 m
radius for the 36 airgun array. The 500 m EZ would 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 would be shut down.
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 SELcum and
peak SPL), while also providing a consistent, reasonably observable
zone within which PSOs would typically be able to conduct effective
observational effort. Additionally, a 500 m EZ is expected to minimize
the likelihood that marine
[[Page 30515]]
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.
Pre-Clearance and Ramp-Up
Ramp-up (sometimes referred to as ``soft start'') means the gradual
and systematic increase of emitted sound levels from an airgun array.
Ramp-up begins by first activating a single airgun of the smallest
volume, followed by doubling the number of active elements in stages
until the full complement of an array's airguns are active. Each stage
should be approximately the same duration, and the total duration
should not be less than approximately 20 minutes. The intent of pre-
clearance observation (30 minutes) is to ensure no protected species
are observed within the buffer zone prior to the beginning of ramp-up.
During pre-clearance is the only time observations of protected species
in the buffer zone would prevent operations (i.e., the beginning of
ramp-up). The intent of ramp-up is to warn protected species of pending
seismic 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-
clearance and ramp-up requirements:
The operator must notify a designated PSO of the planned
start of ramp-up as agreed upon with the lead PSO; the notification
time should not be less than 60 minutes prior to the planned ramp-up in
order to allow the PSOs time to monitor the exclusion and buffer zones
for 30 minutes prior to the initiation of ramp-up (pre-clearance).
Ramp-ups shall be scheduled so as to minimize the time
spent with the source activated prior to reaching the designated run-
in.
One of the PSOs conducting pre-clearance observations must
be notified again immediately prior to initiating ramp-up procedures
and the operator must receive confirmation from the PSO to proceed.
Ramp-up may not be initiated if any marine mammal is
within the applicable exclusion or buffer zone. If a marine mammal is
observed within the applicable exclusion zone or the buffer zone during
the 30 minute pre-clearance period, ramp-up may not begin until the
animal(s) has been observed exiting the zones or until an additional
time period has elapsed with no further sightings (15 minutes for small
odontocetes and 30 minutes for all other species).
Ramp-up shall begin by activating a single airgun of the
smallest volume in the array and shall continue in stages by doubling
the number of active elements at the commencement of each stage, with
each stage of approximately the same duration. Duration shall not be
less than 20 minutes. The operator must provide information to the PSO
documenting that appropriate procedures were followed.
PSOs must monitor the exclusion and buffer zones during
ramp-up, and ramp-up must cease and the source must be shut down upon
observation of a marine mammal within the applicable exclusion zone.
Once ramp-up has begun, observations of marine mammals within the
buffer zone do not require shutdown or powerdown, but such observation
shall be communicated to the operator to prepare for the potential
shutdown or powerdown.
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.
If the acoustic source is shut down for brief periods
(i.e., less than 30 minutes) for reasons other than that described for
shutdown and powerdown (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 exclusion zone. For
any longer shutdown, pre-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-clearance
watch of 30 min is not required.
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-clearance of 30
min.
Shutdown and Powerdown
The shutdown of an airgun array requires the immediate de-
activation of all individual airgun elements of the array while a
powerdown requires immediate de-activation of all individual airgun
elements of the array except the single 40-in\3\ airgun. Any PSO on
duty will have the authority to delay the start of survey operations or
to call for shutdown or powerdown of the acoustic source if a marine
mammal is detected within the applicable exclusion zone. 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 and powerdown commands are conveyed swiftly while
allowing PSOs to maintain watch. When both visual and acoustic PSOs are
on duty, all detections will be immediately communicated to the
remainder of the on-duty PSO team for potential verification of visual
observations by the acoustic PSO or of acoustic detections by visual
PSOs. When the airgun array is active (i.e., anytime one or more
airguns is active, including during ramp-up and powerdown) and (1) a
marine mammal appears within or enters the applicable exclusion zone
and/or (2) a marine mammal (other than delphinids, see below) is
detected acoustically and localized within the applicable exclusion
zone, the acoustic source will be shut down. When shutdown is called
for by a PSO, the acoustic source will be immediately deactivated and
any dispute resolved only following deactivation. Additionally,
shutdown will occur whenever PAM alone (without visual sighting),
confirms presence of marine mammal(s) in the EZ. If the acoustic PSO
cannot confirm presence within the EZ, visual PSOs will be notified but
shutdown is not required.
Following a shutdown, airgun activity would not resume until the
marine mammal has cleared the 500 m EZ. The animal would be considered
to have cleared the 500 m EZ if it is visually observed to have
departed the 500 m EZ, or it has not been seen within the 500 m EZ for
15 min in the case of small odontocetes and pinnipeds, or 30 min in the
case of mysticetes and large odontocetes, including sperm, pygmy sperm,
dwarf sperm, and beaked whales.
The shutdown requirement can be waived for small dolphins in which
case the acoustic source shall be powered down to the single 40-in\3\
airgun if an individual is visually detected within the exclusion zone.
As defined here, the small delphinoid group is intended to encompass
those members of the Family Delphinidae most likely to voluntarily
approach the source vessel for purposes
[[Page 30516]]
of interacting with the vessel and/or airgun array (e.g., bow riding).
This exception to the shutdown requirement would apply solely to
specific genera of small dolphins--Tursiops, Delphinus, Lagenodelphis,
Lagenorhynchus, Lissodelphis, Stenella and Steno--The acoustic source
shall be powered down to 40-in\3\ airgun if an individual belonging to
these genera is visually detected within the 500 m exclusion zone.
b. Powerdown conditions shall be maintained until delphinids for
which shutdown is waived are no longer observed within the 500 m
exclusion zone, following which full-power operations may be resumed
without ramp-up. Visual PSOs may elect to waive the powerdown
requirement if delphinids for which shutdown is waived to be
voluntarily approaching the vessel for the purpose of interacting with
the vessel or towed gear, and may use best professional judgment in
making this decision.
We include this small delphinoid exception because power-down/
shutdown requirements for small delphinoids under all circumstances
represent practicability concerns without likely commensurate benefits
for the animals in question. Small delphinoids 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 delphinoids
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). 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 delphinoids) are no more likely to incur
auditory injury than are small delphinoids, they are much less likely
to approach vessels. Therefore, retaining a power-down/shutdown
requirement for large delphinoids 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 power-down/shutdown requirement for large delphinoids 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 source vessel.
Powerdown conditions shall be maintained until the marine mammal(s)
of the above listed genera are no longer observed within the exclusion
zone, following which full-power operations may be resumed without
ramp-up. Additionally, visual PSOs may elect to waive the powerdown
requirement if the small dolphin(s) appear to be voluntarily
approaching the vessel for the purpose of interacting with the vessel
or towed gear, and may use best professional judgment in making this
decision. Visual PSOs shall use best professional judgment in making
the decision to call for a shutdown if there is uncertainty regarding
identification (i.e., whether the observed marine mammal(s) belongs to
one of the delphinid genera for which shutdown is waived or one of the
species with a larger exclusion zone). If PSOs observe any behaviors in
a small delphinid for which shutdown is waived that indicate an adverse
reaction, then powerdown will be initiated immediately.
Upon implementation of shutdown, the source may be reactivated
after the marine mammal(s) has been observed exiting the applicable
exclusion zone (i.e., animal is not required to fully exit the buffer
zone where applicable) or following 15 minutes for small odontocetes
and 30 minutes for all other species with no further observation of the
marine mammal(s).
Vessel Strike Avoidance
These measures apply to all vessels associated with the planned
survey activity; however, we note that 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. These measures include the following:
1. Vessel operators and crews must maintain a vigilant watch for
all marine mammals and slow down, stop their vessel, or alter course,
as appropriate and regardless of vessel size, to avoid striking any
marine mammal. A single marine mammal at the surface may indicate the
presence of submerged animals in the vicinity of the vessel; therefore,
precautionary measures should be exercised when an animal is observed.
A visual observer aboard the vessel must monitor a vessel strike
avoidance zone around the vessel (specific distances detailed below),
to ensure the potential for strike is minimized. Visual observers
monitoring the vessel strike avoidance zone can 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 and broadly to identify a marine mammal to
broad taxonomic group (i.e., as a large whale or other marine mammal).
2. Vessel speeds must be reduced to 10 kn or less when mother/calf
pairs, pods, or large assemblages of any marine mammal are observed
near a vessel.
3. All vessels must maintain a minimum separation distance of 100 m
from large whales (i.e., sperm whales and all baleen whales.
4. All vessels must attempt to maintain a minimum separation
distance of 50 m from all other marine mammals, with an exception made
for those animals that approach the vessel.
5. When marine mammals are sighted while a vessel is underway, the
vessel should 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 should reduce speed and shift
the engine to neutral, not engaging the engines until animals are clear
of the area. This recommendation does not apply to any vessel towing
gear.
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 proposed
measures, NMFS has preliminarily determined that the 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.
[[Page 30517]]
Proposed 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
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 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.
Vessel-Based Visual Monitoring
As described above, PSO observations would take place during
daytime airgun operations and nighttime start ups (if applicable) of
the airguns. During seismic operations, at least five visual PSOs would
be based aboard the Langseth. Monitoring shall be conducted in
accordance with the following requirements:
The operator shall provide PSOs with bigeye binoculars
(e.g., 25 x 150; 2.7 view angle; individual ocular focus; height
control) of appropriate quality (i.e., Fujinon or equivalent) solely
for PSO use. These shall be pedestal-mounted on the deck at the most
appropriate vantage point that provides for optimal sea surface
observation, PSO safety, and safe operation of the vessel.
The operator will work with the selected third-party
observer provider to ensure PSOs have all equipment (including backup
equipment) needed to adequately perform necessary tasks, including
accurate determination of distance and bearing to observed marine
mammals. (c) PSOs must have the following requirements and
qualifications:
PSOs shall be independent, dedicated, trained visual and
acoustic PSOs and must be employed by a third-party observer provider.
PSOs shall have no tasks other than to conduct
observational effort (visual or acoustic), collect data, and
communicate with and instruct relevant vessel crew with regard to the
presence of protected species and mitigation requirements (including
brief alerts regarding maritime hazards),
PSOs shall have successfully completed an approved PSO
training course appropriate for their designated task (visual or
acoustic). Acoustic PSOs are required to complete specialized training
for operating PAM systems and are encouraged to have familiarity with
the vessel with which they will be working.
PSOs can act as acoustic or visual observers (but not at
the same time) as long as they demonstrate that their training and
experience are sufficient to perform the task at hand.
NMFS must review and approve PSO resumes accompanied by a
relevant training course information packet that includes the name and
qualifications (i.e., experience, training completed, or educational
background) of the instructor(s), the course outline or syllabus, and
course reference material as well as a document stating successful
completion of the course.
NMFS shall have one week to approve PSOs from the time
that the necessary information is submitted, after which PSOs meeting
the minimum requirements shall automatically be considered approved.
PSOs must successfully complete relevant training,
including completion of all required coursework and passing (80 percent
or greater) a written and/or oral examination developed for the
training program.
PSOs must have successfully attained a bachelor's degree
from an accredited college or university with a major in one of the
natural sciences, a minimum of 30 semester hours or equivalent in the
biological sciences, and at least one undergraduate course in math or
statistics.
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 one week of receipt of submitted information. Alternate
experience that may be considered includes, but is not limited to (1)
secondary education and/or experience comparable to PSO duties; (2)
previous work experience conducting academic, commercial, or
government-sponsored protected species surveys; or (3) previous work
experience as a PSO; the PSO should demonstrate good standing and
consistently good performance of PSO duties.
For data collection purposes, PSOs shall use standardized data
collection forms, whether hard copy or electronic. PSOs shall record
detailed information about any implementation of mitigation
requirements, including the distance of animals to the acoustic source
and description of specific actions that ensued, the behavior of the
animal(s), any observed changes in behavior before and after
implementation of mitigation, and if shutdown was implemented, the
length of time before any subsequent ramp-up of the acoustic source. If
required mitigation was not implemented, PSOs should record a
description of the circumstances. At a minimum, the following
information must be recorded:
Vessel names (source vessel and other vessels associated
with survey) and call signs;
PSO names and affiliations;
Dates of departures and returns to port with port name;
Date and participants of PSO briefings;
Dates and times (Greenwich Mean Time) of survey effort and
times corresponding with PSO effort;
Vessel location (latitude/longitude) when survey effort
began and ended and vessel location at beginning and end of visual PSO
duty shifts;
Vessel heading and speed at beginning and end of visual
PSO duty shifts and upon any line change;
[[Page 30518]]
Environmental conditions while on visual survey (at
beginning and end of PSO shift and whenever conditions changed
significantly), including BSS and any other relevant weather conditions
including cloud cover, fog, sun glare, and overall visibility to the
horizon;
Factors that may have contributed to impaired observations
during each PSO shift change or as needed as environmental conditions
changed (e.g., vessel traffic, equipment malfunctions); and
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-clearance, ramp-up, shutdown, testing, shooting, ramp-up
completion, end of operations, streamers, etc.).
The following information should be recorded upon visual
observation of any protected species:
Watch status (sighting made by PSO on/off effort,
opportunistic, crew, alternate vessel/platform);
PSO who sighted the animal;
Time of sighting;
Vessel location at time of sighting;
Water depth;
Direction of vessel's travel (compass direction);
Direction of animal's travel relative to the vessel;
Pace of the animal;
Estimated distance to the animal and its heading relative
to vessel at initial sighting;
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;
Estimated number of animals (high/low/best);
Estimated number of animals by cohort (adults, yearlings,
juveniles, calves, group composition, etc.);
Description (as many distinguishing features as possible
of each individual seen, including length, shape, color, pattern, scars
or markings, shape and size of dorsal fin, shape of head, and blow
characteristics);
Detailed behavior observations (e.g., number of blows/
breaths, number of surfaces, breaching, spyhopping, diving, feeding,
traveling; as explicit and detailed as possible; note any observed
changes in behavior);
Animal's closest point of approach (CPA) and/or closest
distance from any element of the acoustic source;
Platform activity at time of sighting (e.g., deploying,
recovering, testing, shooting, data acquisition, other); and
Description of any actions implemented in response to the
sighting (e.g., delays, shutdown, ramp-up) and time and location of the
action.
If a marine mammal is detected while using the PAM system, the
following information should be recorded:
An acoustic encounter identification number, and whether
the detection was linked with a visual sighting;
Date and time when first and last heard;
Types and nature of sounds heard (e.g., clicks, whistles,
creaks, burst pulses, continuous, sporadic, strength of signal);
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.
A report would be submitted to NMFS within 90 days after the end of
the cruise. The report would describe the operations that were
conducted and sightings of marine mammals near the operations. The
report would provide full documentation of methods, results, and
interpretation pertaining to all monitoring. The 90-day report would
summarize the dates and locations of seismic operations, and all marine
mammal sightings (dates, times, locations, activities, associated
seismic survey activities). The report would 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 on
the trackline but not detected.
L-DEO will be required to shall submit a draft comprehensive report
to NMFS on all activities and monitoring results within 90 days of the
completion of the survey or expiration of the IHA, whichever comes
sooner. The report must describe all activities conducted and sightings
of protected species near the activities, must provide full
documentation of methods, results, and interpretation pertaining to all
monitoring, and must summarize the dates and locations of survey
operations and all protected species sightings (dates, times,
locations, activities, associated survey activities). The draft report
shall also include geo-referenced time-stamped vessel tracklines for
all time periods during which airguns were operating. Tracklines should
include points recording any change in airgun status (e.g., when the
airguns began operating, when they were turned off, or when they
changed from full array to single gun or vice versa). GIS files shall
be provided in ESRI shapefile format and include the UTC date and time,
latitude in decimal degrees, and longitude in decimal degrees. All
coordinates shall be referenced to the WGS84 geographic coordinate
system. In addition to the report, all raw observational data shall be
made available to NMFS. The report must summarize the information
submitted in interim monthly reports as well as additional data
collected as described above and the IHA. The draft report must be
accompanied by a certification from the lead PSO as to the accuracy of
the report, and the lead PSO may submit directly NMFS a statement
concerning implementation and effectiveness of the required mitigation
and monitoring. A final report must be submitted within 30 days
following 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 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' 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 7 and 8, given that NMFS expects the anticipated effects of the
proposed seismic survey to be similar in nature.
[[Page 30519]]
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 serious injury or mortality would
occur as a result of L-DEO's proposed survey, even in the absence of
proposed mitigation. Thus the proposed authorization does not authorize
any mortality. As discussed in the Potential Effects section, non-
auditory physical effects, stranding, and vessel strike are not
expected to occur.
We propose to authorize a limited number of instances of Level A
harassment of 18 species and Level B harassment of 39 marine mammal
species. However, we believe that any PTS incurred in marine mammals as
a result of the proposed activity would be in the form of only a small
degree of PTS, not total deafness, and would be unlikely to affect the
fitness of any individuals, because of the constant movement of both
the Langseth and of the marine mammals in the project areas, as well as
the fact that the vessel is not expected to remain in any one area in
which individual marine mammals would be expected to concentrate for an
extended period of time (i.e., since the duration of exposure to loud
sounds will be relatively short). Also, as described above, we expect
that marine mammals would be likely to move away from a sound source
that represents an aversive stimulus, especially at levels that would
be expected to result in PTS, given sufficient notice of the Langseth's
approach due to the vessel's relatively low speed when conducting
seismic surveys. We expect that the majority of takes would be in the
form of short-term Level B behavioral harassment in the form of
temporary avoidance of the area or decreased foraging (if such activity
were occurring), reactions that are considered to be of low severity
and with no lasting biological consequences (e.g., Southall et al.,
2007).
Potential impacts to marine mammal habitat were discussed
previously in this document (see Potential Effects of the Specified
Activity on Marine Mammals and their Habitat). Marine mammal habitat
may be impacted by elevated sound levels, but these impacts would 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 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 (~32 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.
The activity is expected to impact a small percentage of all marine
mammal stocks that would be affected by L-DEO's proposed survey (less
than 20 percent of all species). Additionally, the acoustic
``footprint'' of the proposed survey would be 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 proposed survey area.
The proposed 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 and acoustic observers, and by
minimizing the severity of any potential exposures via power downs and/
or 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 proposed mitigation will be
effective in preventing at least some extent of potential PTS in marine
mammals that may otherwise occur in the absence of the proposed
mitigation.
The ESA-listed marine mammal species under our jurisdiction that
are likely to be taken by the proposed surveys include the endangered
sei, fin, blue, sperm, gray, North Pacific Right, Western North Pacific
DPS humpback, and Main Hawaiian Islands Insular DPS false killer whale
as well as the Hawaiian monk seal. We propose to authorize very small
numbers of takes for these species relative to their population sizes.
Therefore, we do not expect population-level impacts to any of these
species. The other marine mammal species that may be taken by
harassment during the proposed survey are not listed as threatened or
endangered under the ESA. With the exception of the northern fur seal,
none of the non-listed marine mammals for which we propose to authorize
take are considered ``depleted'' or ``strategic'' by NMFS under the
MMPA.
The tracklines of the Hawaii survey either traverse or are proximal
to BIAs for 11 species that NMFS has proposed to authorize for take.
Ten of the BIAs pertain to small and resident cetacean populations
while a breeding BIA has been delineated for humpback whales. However,
this designation is only applicable to humpback whales in the December
through March timeframe (Baird et al., 2015). Since the Hawaii survey
is proposed for August, there will be no effects on humpback whales.
For cetacean species with small and resident BIAs in the Hawaii survey
area, that designation is applicable year-round. There are 19 days of
seismic operations proposed for the Hawaii survey. Only a portion of
those days would maintain seismic operations along Tracklines 1 and 2.
No physical impacts to BIA habitat are anticipated from seismic
activities. While SPLs of sufficient strength have been known to cause
injury to fish and fish mortality, the most likely impact to prey
species from survey activities would be temporary avoidance of the
affected area. 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 BIAs, 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 the designated BIAs.
NMFS concludes that exposures to marine mammal species and stocks
due to L-DEO's proposed survey would result in only short-term
(temporary and short in duration) effects to individuals exposed.
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. NMFS does not
anticipate the proposed take estimates to impact annual rates of
recruitment or survival.
In summary and as described above, the following factors primarily
support our preliminary determination that the impacts resulting from
this activity are not expected to adversely affect the marine mammal
species or stocks through effects on annual rates of recruitment or
survival:
No mortality is anticipated or authorized;
The proposed activity is temporary and of relatively short
duration (~32 days);
[[Page 30520]]
The anticipated impacts of the proposed activity on marine
mammals would primarily be temporary behavioral changes due to
avoidance of the area around the survey vessel;
The number of instances of PTS that may occur are expected
to be very small in number. Instances of PTS that are incurred in
marine mammals would 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);
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 potential adverse effects on fish or invertebrate
species that serve as prey species for marine mammals from the proposed
survey would be temporary and spatially limited;
The proposed mitigation measures, including visual and
acoustic monitoring, power-downs, 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 proposed monitoring and
mitigation measures, NMFS preliminarily 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 section 101(a)(5)(D) of the MMPA for specified
activities other than military readiness activities. The MMPA does not
define small numbers; 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. Tables 7 and 8 provide numbers of take by Level A
harassment and Level B harassment proposed for authorization. These are
the numbers we use for purposes of the small numbers analysis.
The numbers of marine mammals that we propose for authorized take
would be considered small relative to the relevant populations (19.4
percent for all species) for the species for which abundance estimates
are available.
Based on the analysis contained herein of the proposed activity
(including the proposed mitigation and monitoring measures) and the
anticipated take of marine mammals, NMFS preliminarily finds that small
numbers of marine mammals will be taken relative to the population size
of the affected species.
Unmitigable Adverse Impact Analysis and Determination
There are no relevant subsistence uses of the affected marine
mammal stocks or species implicated by this action. Therefore, NMFS has
determined that the total taking of affected species or stocks would
not have an unmitigable adverse impact on the availability of such
species or stocks for taking for subsistence purposes.
Endangered Species Act (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 Permits and Conservation Division is proposing to
authorize the incidental take of marine mammals which are listed under
the ESA (the North Pacific right, sei, fin, blue, sperm whales, Western
North Pacific DPS humpback whale, gray whale, the Hawaiian Islands
Insular DPS false killer whale, and the Hawaiian monk seal. We have
requested initiation of Section 7 consultation with the Interagency
Cooperation Division for the issuance of this IHA. NMFS will conclude
the ESA section 7 consultation prior to reaching a determination
regarding the proposed issuance of the authorization.
Proposed Authorization
As a result of these preliminary determinations, NMFS proposes to
issue an IHA to L-DEO for conducting seismic surveys in the Pacific
Ocean near Hawaii in summer/early fall of 2018 and in the Emperor
Seamounts area in spring/early summer 2019, provided the previously
mentioned mitigation, monitoring, and reporting requirements are
incorporated. This section contains a draft of the IHA itself. The
wording contained in this section is proposed for inclusion in the IHA
(if issued).
1. This incidental harassment authorization (IHA) is valid for a
period of one year from the date of issuance.
2. This IHA is valid only for marine geophysical survey activity,
as specified in L-DEO's IHA application and using an array aboard the
R/V Langseth with characteristics specified in the IHA application, in
the Pacific Ocean near the Main Hawaiian Islands and the Emperor
Seamounts.
3. General Conditions
(a) A copy of a the IHA must be in the possession of the vessel
operator, other relevant personnel, the lead PSO, and any other
relevant designees operating under the authority of the IHA.
(b) L-DEO shall instruct relevant vessel personnel with regard to
the authority of the protected species monitoring team, and shall
ensure that relevant vessel personnel and the protected species
monitoring team participate in a joint onboard briefing (hereafter PSO
briefing) led by the vessel operator and lead PSO to ensure that
responsibilities, communication procedures, protected species
monitoring protocols, operational procedures, and IHA requirements are
clearly understood. This PSO briefing must be repeated when relevant
new personnel join the survey operations.
(c) The species authorized for taking are listed in Table 7 and 8.
The taking, by Level A and Level B harassment only, is limited to the
species and numbers listed in Table 7 and 8. Any taking exceeding the
authorized amounts listed in Table 7 and 8 is prohibited and may result
in the modification, suspension, or revocation of this IHA.
(d) The taking by serious injury or death of any species of marine
mammal is prohibited and may result in the modification, suspension, or
revocation of this IHA.
(e) During use of the airgun(s), if marine mammal species other
than those listed in Table 7 and 8 are detected by PSOs, the airgun
array must be shut down.
4. Mitigation Requirements
The holder of this Authorization is required to implement the
following mitigation measures:
(a) L-DEO must use at least five dedicated, trained, NMFS-approved
Protected Species Observers (PSOs). The PSOs must have no tasks other
than to conduct observational effort, record
[[Page 30521]]
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.
(b) At least one of the visual and two of the acoustic PSOs aboard
the vessel must have a minimum of 90 days at-sea experience working in
those roles, respectively, during a deep penetration seismic survey,
with no more than 18 months elapsed since the conclusion of the at-sea
experience.
(c) Visual Observation
(i) 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 and 30 minutes prior to and during nighttime ramp-
ups of the airgun array.
(ii) Visual PSOs shall coordinate to ensure 360[deg] visual
coverage around the vessel from the most appropriate observation posts,
and shall conduct visual observations using binoculars and the naked
eye while free from distractions and in a consistent, systematic, and
diligent manner.
(iii) PSOs shall establish and monitor the exclusion and buffer
zones. These zones shall be based upon the radial distance from the
edges of the acoustic source (rather than being based on the center of
the array or around the vessel itself). During use of the acoustic
source (i.e., anytime airguns are active, including ramp-up),
occurrences of marine mammals within the buffer zone (but outside the
exclusion zone) shall be communicated to the operator to prepare for
the potential shutdown or powerdown of the acoustic source.
(iv) Visual PSOs shall 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.
(v) During good conditions (e.g., daylight hours; Beaufort sea
state (BSS) 3 or less), visual PSOs shall conduct observations when the
acoustic source is not operating for comparison of sighting rates and
behavior with and without use of the acoustic source and between
acquisition periods, to the maximum extent practicable.
(vi) Visual PSOs may be on watch for a maximum of two 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
(d) Acoustic Monitoring
(i) The source vessel 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.
(ii) Acoustic PSOs shall immediately communicate all detections to
visual PSOs, when visual PSOs are on duty, including any determination
by the PSO regarding species identification, distance, and bearing and
the degree of confidence in the determination.
(iii) Acoustic PSOs may be on watch for a maximum of four
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 may not exceed 12 hours per
24-hour period for any individual PSO.
(iv) 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 two
hours without acoustic monitoring during daylight hours only under the
following conditions:
a. Sea state is less than or equal to BSS 4;
b. With the exception of delphinids, no marine mammals detected
solely by PAM in the applicable exclusion zone in the previous two
hours;
c. 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
d. Operations with an active acoustic source, but without an
operating PAM system, do not exceed a cumulative total of four hours in
any 24-hour period.
(e) Exclusion zone and buffer zone
(i) PSO shall establish and monitor a 500 m exclusion zone and
1,000 m buffer zone. The exclusion zone encompasses the area at and
below the sea surface out to a radius of 500 meters from the edges of
the airgun array (0-500 meters). The buffer zone encompasses the area
at and below the sea surface from the edge of the 0-500 meter exclusion
zone, out to a radius of 1000 meters from the edges of the airgun array
(500-1,000 meters).
(f) Pre-clearance and Ramp-up
(i) A ramp-up procedure shall be required at all times as part of
the activation of the acoustic source.
(v) Ramp-up may not be initiated if any marine mammal is within the
exclusion or buffer zone. If a marine mammal is observed within the
exclusion zone or the buffer zone during the 30 minute pre-clearance
period, ramp-up may not begin until the animal(s) has been observed
exiting the zone or until an additional time period has elapsed with no
further sightings (15 minutes for small odontocetes and pinnipeds and
30 minutes for all other species).
(vi) Ramp-up shall begin by activating a single airgun of the
smallest volume in the array and shall continue in stages by doubling
the number of active elements at the commencement of each stage, with
each stage of approximately the same duration. Duration shall not be
less than 20 minutes.
(vii) PSOs must monitor the exclusion and buffer zones during ramp-
up, and ramp-up must cease and the source must be shut down upon
observation of a marine mammal within the exclusion zone. Once ramp-up
has begun, observations of marine mammals within the buffer zone do not
require shutdown or powerdown, but such observation shall be
communicated to the operator to prepare for the potential shutdown or
powerdown.
(viii) 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.
(ix) If the acoustic source is shut down for brief periods (i.e.,
less than 30 minutes) for reasons other than that described for
shutdown and powerdown (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 exclusion zone. For
any longer shutdown, pre-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-clearance
watch of 30 min is not required.
(x) 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-clearance of 30 min.
(g) Shutdown and Powerdown
[[Page 30522]]
(i) Any PSO on duty shall have the authority to delay the start of
survey operations or to call for shutdown or powerdown of the acoustic
source if a marine mammal is detected within the applicable exclusion
zone.
(ii) The operator shall establish and maintain clear lines of
communication directly between PSOs on duty and crew controlling the
acoustic source to ensure that shutdown and powerdown commands are
conveyed swiftly while allowing PSOs to maintain watch.
(iii) When both visual and acoustic PSOs are on duty, all
detections shall 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.
(iv) When the airgun array is active (i.e., anytime one or more
airguns is active, including during ramp-up and powerdown) and (1) a
marine mammal (excluding delphinids) appears within or enters the
exclusion zone and/or (2) a marine mammal is detected acoustically and
localized within the exclusion zone, the acoustic source shall be shut
down. When shutdown is called for by a PSO, the airgun array shall be
immediately deactivated. Any questions regarding a PSO shutdown shall
be resolved after deactivation.
(v) Shutdown shall occur whenever PAM alone (without visual
sighting), confirms presence of marine mammal(s) (other than
delphinids) in the 500 m exclusion zone. If the acoustic PSO cannot
confirm presence within exclusion zone, visual PSOs shall be notified
but shutdown is not required.
(v) The shutdown requirement shall be waived for small dolphins of
the following genera: Tursiops, Delphinus, Lagenodelphis,
Lagenorhynchus, Lissodelphis, Stenella and Steno.
a. The acoustic source shall be powered down to 40-in\3\ airgun if
an individual belonging to these genera is visually detected within the
500 m exclusion zone.
b. Powerdown conditions shall be maintained until delphinids for
which shutdown is waived are no longer observed within the 500 m
exclusion zone, following which full-power operations may be resumed
without ramp-up. Visual PSOs may elect to waive the powerdown
requirement if delphinids for which shutdown is waived to be
voluntarily approaching the vessel for the purpose of interacting with
the vessel or towed gear, and may use best professional judgment in
making this decision.
d. If PSOs observe any behaviors in delphinids for which shutdown
is waived that indicate an adverse reaction, then powerdown shall be
initiated.
(vi) Visual PSOs shall use best professional judgment in making the
decision to call for a shutdown if there is uncertainty regarding
identification (i.e., whether the observed marine mammal(s) belongs to
one of the delphinid genera for which shutdown is waived).
(vii) Upon implementation of shutdown, the source may be
reactivated after the marine mammal(s) has been observed exiting the
applicable exclusion zone (i.e., animal is not required to fully exit
the buffer zone where applicable) or following a 30-minute clearance
period with no further observation of the marine mammal(s).
(g) Vessel operators and crews must maintain a vigilant watch for
all marine mammals and slow down, stop their vessel, or alter course,
as appropriate and regardless of vessel size, to avoid striking any
marine mammal. A visual observer aboard the vessel must monitor a
vessel strike avoidance zone around the vessel (specific distances
detailed below), to ensure the potential for strike is minimized.
(i) Vessel speeds must be reduced to 10 kn or less when mother/calf
pairs, pods, or large assemblages of any marine mammal are observed
near a vessel.
a. Vessels must maintain a minimum separation distance of 100 m
from large whales (i.e., sperm whales and all baleen whales.
b. Vessels must attempt to maintain a minimum separation distance
of 50 m from all other marine mammals, with an exception made for those
animals that approach the vessel.
c. When marine mammals are sighted while a vessel is underway, the
vessel should take action as necessary to avoid violating the relevant
separation distance. If marine mammals are sighted within the relevant
separation distance, the vessel should reduce speed and shift the
engine to neutral, not engaging the engines until animals are clear of
the area. This recommendation does not apply to any vessel towing gear.
5. Monitoring Requirements.
The holder of this Authorization is required to conduct marine
mammal monitoring during survey activity. Monitoring shall be conducted
in accordance with the following requirements:
(a) The operator shall provide PSOs with bigeye binoculars (e.g.,
25 x 150; 2.7 view angle; individual ocular focus; height control) of
appropriate quality (i.e., Fujinon or equivalent) solely for PSO use.
These shall be pedestal-mounted on the deck at the most appropriate
vantage point that provides for optimal sea surface observation, PSO
safety, and safe operation of the vessel.
(b) The operator shall work with the selected third-party observer
provider to ensure PSOs have all equipment (including backup equipment)
needed to adequately perform necessary tasks, including accurate
determination of distance and bearing to observed marine mammals. Such
equipment, at a minimum, shall include:
(i) PAM shall include a system that has been verified and tested by
the acoustic PSO that will be using it during the trip for which
monitoring is required.
(ii) At least one night-vision device suited for the marine
environment for use during nighttime pre-clearance and ramp-up that
features automatic brightness and gain control, bright light
protection, infrared illumination, and/or optics suited for low-light
situations (e.g., Exelis PVS-7 night vision goggles; Night Optics D-300
night vision monocular; FLIR M324XP thermal imaging camera or
equivalents).
(iii) Reticle binoculars (e.g., 7 x 50) of appropriate quality
(i.e., Fujinon or equivalent) (at least one per PSO, plus backups)
(iv) Global Positioning Units (GPS) (at least one per PSO, plus
backups)
(v) Digital single-lens reflex cameras of appropriate quality that
capture photographs and video (i.e., Canon or equivalent) (at least one
per PSO, plus backups)
(vi) Compasses (at least one per PSO, plus backups)
(vii) Radios for communication among vessel crew and PSOs (at least
one per PSO, plus backups)
(viii) Any other tools necessary to adequately perform necessary
PSO tasks.
(c) Protected Species Observers (PSOs, Visual and Acoustic)
Qualifications
(i) PSOs shall be independent, dedicated, trained visual and
acoustic PSOs and must be employed by a third-party observer provider,
(ii) PSOs shall have no tasks other than to conduct observational
effort (visual or acoustic), collect data, and communicate with and
instruct relevant vessel crew with regard to the presence of protected
species and mitigation requirements (including brief alerts regarding
maritime hazards), and
(iii) PSOs shall have successfully completed an approved PSO
training course appropriate for their designated task (visual or
acoustic). Acoustic PSOs are required to complete specialized training
for operating PAM systems and are encouraged to have familiarity with
[[Page 30523]]
the vessel with which they will be working.
(iv) 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.
(v) 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.
(vi) NMFS shall have one week to approve PSOs from the time that
the necessary information is submitted, after which PSOs meeting the
minimum requirements shall automatically be considered approved.
(vii) One visual PSO with experience as shown in 4(b) shall be
designated as the lead for the entire protected species observation
team. The lead shall coordinate duty schedules and roles for the PSO
team and serve as primary point of contact for the vessel operator. To
the maximum extent practicable, the lead PSO shall devise the duty
schedule such that experienced PSOs are on duty with those PSOs with
appropriate training but who have not yet gained relevant experience.
(viii) 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.
(ix). 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.
(x) 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 one week of receipt of submitted information. Alternate
experience that may be considered includes, but is not limited to (1)
secondary education and/or experience comparable to PSO duties; (2)
previous work experience conducting academic, commercial, or
government-sponsored protected species surveys; or (3) previous work
experience as a PSO; the PSO should demonstrate good standing and
consistently good performance of PSO duties.
(d) Data Collection
(i) PSOs shall use standardized data collection forms, whether hard
copy or electronic. PSOs shall record detailed information about any
implementation of mitigation requirements, including the distance of
animals to the acoustic source and description of specific actions that
ensued, the behavior of the animal(s), any observed changes in behavior
before and after implementation of mitigation, and if shutdown was
implemented, the length of time before any subsequent ramp-up of the
acoustic source. If required mitigation was not implemented, PSOs
should record a description of the circumstances.
(ii) At a minimum, the following information must be recorded:
a. Vessel names (source vessel and other vessels associated with
survey) and call signs;
b. PSO names and affiliations;
c. Dates of departures and returns to port with port name;
d. Date and participants of PSO briefings (as discussed in General
Requirements. 2.)
e. Dates and times (Greenwich Mean Time) of survey effort and times
corresponding with PSO effort;
f. Vessel location (latitude/longitude) when survey effort began
and ended and vessel location at beginning and end of visual PSO duty
shifts;
g. Vessel heading and speed at beginning and end of visual PSO duty
shifts and upon any line change;
h. 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;
i. 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);
j. 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-clearance, ramp-up, shutdown, testing, shooting, ramp-up
completion, end of operations, streamers, etc.); and
(iii). Upon visual observation of any protected species, the
following information shall be recorded:
a. Watch status (sighting made by PSO on/off effort, opportunistic,
crew, alternate vessel/platform);
b. PSO who sighted the animal;
c. Time of sighting;
d. Vessel location at time of sighting;
e. Water depth;
f. Direction of vessel's travel (compass direction);
g. Direction of animal's travel relative to the vessel;
h. Pace of the animal;
i. Estimated distance to the animal and its heading relative to
vessel at initial sighting;
j. 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;
k. Estimated number of animals (high/low/best);
l. Estimated number of animals by cohort (adults, yearlings,
juveniles, calves, group composition, etc.);
m. 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);
n. 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);
o. Animal's closest point of approach (CPA) and/or closest distance
from any element of the acoustic source;
p. Platform activity at time of sighting (e.g., deploying,
recovering, testing, shooting, data acquisition, other); and
q. Description of any actions implemented in response to the
sighting (e.g., delays, shutdown, ramp-up) and time and location of the
action.
(iv) If a marine mammal is detected while using the PAM system, the
following information should be recorded:
a. An acoustic encounter identification number, and whether the
detection was linked with a visual sighting;
b. Date and time when first and last heard;
c. Types and nature of sounds heard (e.g., clicks, whistles,
creaks, burst pulses, continuous, sporadic, strength of signal);
d. 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.
6. Reporting
(a) L-DEO shall submit a draft comprehensive report to NMFS on all
activities and monitoring results within
[[Page 30524]]
90 days of the completion of the survey or expiration of the IHA,
whichever comes sooner. The report must describe all activities
conducted and sightings of protected species near the activities, must
provide full documentation of methods, results, and interpretation
pertaining to all monitoring, and must summarize the dates and
locations of survey operations and all protected species sightings
(dates, times, locations, activities, associated survey activities).
The draft report shall also include geo-referenced time-stamped vessel
tracklines for all time periods during which airguns were operating.
Tracklines should include points recording any change in airgun status
(e.g., when the airguns began operating, when they were turned off, or
when they changed from full array to single gun or vice versa). GIS
files shall be provided in ESRI shapefile format and include the UTC
date and time, latitude in decimal degrees, and longitude in decimal
degrees. All coordinates shall be referenced to the WGS84 geographic
coordinate system. In addition to the report, all raw observational
data shall be made available to NMFS. The report must summarize the
information submitted in interim monthly reports as well as additional
data collected as described above in Data Collection and the IHA. The
draft report must be accompanied by a certification from the lead PSO
as to the accuracy of the report, and the lead PSO may submit directly
NMFS a statement concerning implementation and effectiveness of the
required mitigation and monitoring. A final report must be submitted
within 30 days following resolution of any comments on the draft
report.
(b) Reporting injured or dead protected species:
(i) In the event that the specified activity clearly causes the
take of a marine mammal in a manner not permitted by this IHA, such as
serious injury or mortality, L-DEO shall immediately cease the
specified activities and immediately report the incident to the NMFS
Office of Protected Resources and the NMFS Pacific Islands Regional
Stranding Coordinator. The report must include the following
information:
a. Time, date, and location (latitude/longitude) of the incident;
b. Vessel's speed during and leading up to the incident;
c. Description of the incident;
d. Status of all sound source use in the 24 hours preceding the
incident;
e. Water depth;
f. Environmental conditions (e.g., wind speed and direction,
Beaufort sea state, cloud cover, and visibility);
g. Description of all marine mammal observations in the 24 hours
preceding the incident;
h. Species identification or description of the animal(s) involved;
i. Fate of the animal(s); and
j. Photographs or video footage of the animal(s).
Activities shall not resume until NMFS is able to review the
circumstances of the prohibited take. NMFS will work with L-DEO to
determine what measures are necessary to minimize the likelihood of
further prohibited take and ensure MMPA compliance. L-DEO may not
resume their activities until notified by NMFS.
(ii) In the event that L-DEO discovers an injured or dead marine
mammal, and the lead observer determines that the cause of the injury
or death is unknown and the death is relatively recent (e.g., in less
than a moderate state of decomposition), L-DEO shall immediately report
the incident to the NMFS Office of Protected Resources and the NMFS
Pacific Islands Regional Stranding Coordinator. The report must include
the same information identified in condition 6(b)(i) of this IHA.
Activities may continue while NMFS reviews the circumstances of the
incident. NMFS will work with L-DEO to determine whether additional
mitigation measures or modifications to the activities are appropriate.
(iii) In the event that L-DEO discovers an injured or dead marine
mammal, and the lead observer determines that the injury or death is
not associated with or related to the specified activities (e.g.,
previously wounded animal, carcass with moderate to advanced
decomposition, or scavenger damage), L-DEO shall report the incident to
the NMFS Office of Protected Resources and the Pacific Islands Regional
Stranding Coordinator within 24 hours of the discovery. L-DEO shall
provide photographs or video footage or other documentation of the
sighting to NMFS.
7. This Authorization may be modified, suspended or withdrawn if
the holder fails to abide by the conditions prescribed herein, or if
NMFS determines the authorized taking is having more than a negligible
impact on the species or stock of affected marine mammals.
Request for Public Comments
We request comment on our analyses, the proposed authorization, and
any other aspect of this Notice of Proposed IHA for L-DEO's proposed
surveys. We also request comment on the potential for renewal of this
proposed IHA as described in the paragraph below. Please include with
your comments any supporting data or literature citations to help
inform our final decision on the request for MMPA authorization.
On a case-by-case basis, NMFS may issue a second one-year IHA
without additional notice when (1) another year of identical or nearly
identical activities as described in the Specified Activities section
is planned or (2) the activities would not be completed by the time the
IHA expires and a second IHA would allow for completion of the
activities beyond that described in the Dates and Duration section,
provided all of the following conditions are met:
A request for renewal is received no later than 60 days
prior to expiration of the current IHA.
The request for renewal must include the following:
(1) An explanation that the activities to be conducted beyond the
initial dates either are identical to the previously analyzed
activities or include changes so minor (e.g., reduction in pile size)
that the changes do not affect the previous analyses, take estimates,
or mitigation and monitoring requirements.
(2) A preliminary monitoring report showing the results of the
required monitoring to date and an explanation showing that the
monitoring results do not indicate impacts of a scale or nature not
previously analyzed or authorized.
Upon review of the request for renewal, the status of the
affected species or stocks, and any other pertinent information, NMFS
determines that there are no more than minor changes in the activities,
the mitigation and monitoring measures remain the same and appropriate,
and the original findings remain valid.
Dated: June 21, 2018.
Elaine T. Saiz,
Acting Deputy Director, Office of Protected Resources, National Marine
Fisheries Service.
[FR Doc. 2018-13732 Filed 6-27-18; 8:45 am]
BILLING CODE 3510-22-P