[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





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National Oceanic and Atmospheric Administration





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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]]


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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.

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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 <a href="/cdn-cgi/l/email-protection#2d64797d037d4c58414443486d43424c4c034a425b"><span class="__cf_email__" data-cfemail="eca5b8bcc2bc8d9980858289ac82838d8dc28b839a">[email protected]</span></a>.
    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):

<bullet> Low-frequency cetaceans (mysticetes): Generalized hearing is 
estimated to occur between approximately 7 Hz and 35 kHz;
<bullet> Mid-frequency cetaceans (larger toothed whales, beaked whales, 
and most delphinids): Generalized hearing is estimated to occur between 
approximately 150 Hz and 160 kHz;
<bullet> 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.
<bullet> Pinnipeds in water; Phocidae (true seals): Generalized hearing 
is estimated to occur between approximately 50 Hz to 86 kHz;
<bullet> 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):
    <bullet> 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.
    <bullet> 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.
    <bullet> 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.
    <bullet> 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 SEL<INF>cum</INF> 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<SUP>-</SUP>\6\; 95% 
CI = 0-5.5 x 10<SUP>-</SUP>\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 
SEL<INF>cum</INF> 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 SEL<INF>cum</INF> metric 
considers both level and duration of exposure, as well as auditory 
weighting functions by marine mammal hearing group. In recognition of 
the fact that the requirement to calculate Level A harassment 
ensonified areas could be more technically challenging to predict due 
to the duration component and the use of weighting functions in the new 
SEL<INF>cum</INF> thresholds, NMFS developed an optional User 
Spreadsheet that includes tools to help predict a simple isopleth that 
can be used in conjunction with marine mammal density or occurrence to 
facilitate the estimation of take numbers.
    The values for SEL<INF>cum</INF> 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 SEL<INF>cum</INF> 
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 (SEL<INF>cum</INF> and Peak 
SPL<INF>flat</INF>) 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:
    <bullet> Sea state is less than or equal to BSS 4;
    <bullet> No marine mammals (excluding delphinids) detected solely 
by PAM in the applicable exclusion zone in the previous two hours;
    <bullet> NMFS is notified via email as soon as practicable with the 
time and location in which operations began occurring without an active 
PAM system; and
    <bullet> Operations with an active acoustic source, but without an 
operating PAM system, do not exceed a cumulative total of 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:
    <bullet> The operator must notify a designated PSO of the planned 
start of ramp-up as agreed upon with the lead PSO; the notification 
time should not be less than 60 minutes prior to the planned ramp-up in 
order to allow the PSOs time to monitor the exclusion and buffer zones 
for 30 minutes prior to the initiation of ramp-up (pre-clearance).
    <bullet> Ramp-ups shall be scheduled so as to minimize the time 
spent with the source activated prior to reaching the designated run-
in.
    <bullet> One of the PSOs conducting pre-clearance observations must 
be notified again immediately prior to initiating ramp-up procedures 
and the operator must receive confirmation from the PSO to proceed.
    <bullet> Ramp-up may not be initiated if any marine mammal is 
within the applicable exclusion or buffer zone. If a marine mammal is 
observed within the 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).
    <bullet> Ramp-up shall begin by activating a single airgun of the 
smallest volume in the array and shall continue in stages by doubling 
the number of active elements at the commencement of each stage, with 
each stage of approximately the same duration. Duration shall not be 
less than 20 minutes. The operator must provide information to the PSO 
documenting that appropriate procedures were followed.
    <bullet> PSOs must monitor the 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.
    <bullet> Ramp-up may occur at times of poor visibility, including 
nighttime, if appropriate acoustic monitoring has occurred with no 
detections in the 30 minutes prior to beginning ramp-up. Acoustic 
source activation may only occur at times of poor visibility where 
operational planning cannot reasonably avoid such circumstances.
    <bullet> If the acoustic source is shut down for brief periods 
(i.e., less than 30 minutes) for reasons other than that described for 
shutdown 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.
    <bullet> Testing of the acoustic source involving all elements 
requires ramp-up. Testing limited to individual source elements or 
strings does not require ramp-up but does require pre-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:
    <bullet> Occurrence of marine mammal species or stocks in the area 
in which take is anticipated (e.g., presence, abundance, distribution, 
density).
    <bullet> Nature, scope, or context of likely marine mammal exposure 
to potential stressors/impacts (individual or cumulative, acute or 
chronic), through better understanding of: (1) Action or environment 
(e.g., source characterization, propagation, ambient noise); (2) 
affected species (e.g., life history, dive patterns); (3) co-occurrence 
of marine mammal species with the action; or (4) biological or 
behavioral context of exposure (e.g., age, calving or feeding areas).
    <bullet> Individual marine mammal responses (behavioral or 
physiological) to acoustic stressors (acute, chronic, or cumulative), 
other stressors, or cumulative impacts from multiple stressors.
    <bullet> How anticipated responses to stressors impact either: (1) 
Long-term fitness and survival of individual marine mammals; or (2) 
populations, species, or stocks.
    <bullet> Effects on marine mammal habitat (e.g., marine mammal prey 
species, acoustic habitat, or other important physical components of 
marine mammal habitat).
    <bullet> Mitigation and monitoring effectiveness.

Vessel-Based Visual Monitoring

    As described above, PSO observations 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:
    <bullet> The operator shall provide PSOs with bigeye binoculars 
(e.g., 25 x 150; 2.7 view angle; individual ocular focus; height 
control) of appropriate quality (i.e., Fujinon or equivalent) solely 
for PSO use. These shall be pedestal-mounted on the deck at the most 
appropriate vantage point that provides for optimal sea surface 
observation, PSO safety, and safe operation of the vessel.
    <bullet> The operator will work with the selected third-party 
observer provider to ensure PSOs have all equipment (including backup 
equipment) needed to adequately perform necessary tasks, including 
accurate determination of distance and bearing to observed marine 
mammals. (c) PSOs must have the following requirements and 
qualifications:
    <bullet> PSOs shall be independent, dedicated, trained visual and 
acoustic PSOs and must be employed by a third-party observer provider.
    <bullet> PSOs shall have no tasks other than to conduct 
observational effort (visual or acoustic), collect data, and 
communicate with and instruct relevant vessel crew with regard to the 
presence of protected species and mitigation requirements (including 
brief alerts regarding maritime hazards),
    <bullet> PSOs shall have successfully completed an approved PSO 
training course appropriate for their designated task (visual or 
acoustic). Acoustic PSOs are required to complete specialized training 
for operating PAM systems and are encouraged to have familiarity with 
the vessel with which they will be working.
    <bullet> PSOs can act as acoustic or visual observers (but not at 
the same time) as long as they demonstrate that their training and 
experience are sufficient to perform the task at hand.
    <bullet> NMFS must review and approve PSO resumes accompanied by a 
relevant training course information packet that includes the name and 
qualifications (i.e., experience, training completed, or educational 
background) of the instructor(s), the course outline or syllabus, and 
course reference material as well as a document stating successful 
completion of the course.
    <bullet> 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.
    <bullet> PSOs must successfully complete relevant training, 
including completion of all required coursework and passing (80 percent 
or greater) a written and/or oral examination developed for the 
training program.
    <bullet> PSOs must have successfully attained a bachelor's degree 
from an accredited college or university with a major in one of the 
natural sciences, a minimum of 30 semester hours or equivalent in the 
biological sciences, and at least one undergraduate course in math or 
statistics.
    <bullet> The educational requirements may be waived if the PSO has 
acquired the relevant skills through alternate experience. Requests for 
such a waiver shall be submitted to NMFS and must include written 
justification. Requests shall be granted or denied (with justification) 
by NMFS within 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:
    <bullet> Vessel names (source vessel and other vessels associated 
with survey) and call signs;
    <bullet> PSO names and affiliations;
    <bullet> Dates of departures and returns to port with port name;
    <bullet> Date and participants of PSO briefings;
    <bullet> Dates and times (Greenwich Mean Time) of survey effort and 
times corresponding with PSO effort;
    <bullet> Vessel location (latitude/longitude) when survey effort 
began and ended and vessel location at beginning and end of visual PSO 
duty shifts;
    <bullet> Vessel heading and speed at beginning and end of visual 
PSO duty shifts and upon any line change;

[[Page 30518]]

    <bullet> Environmental conditions while on visual survey (at 
beginning and end of PSO shift and whenever conditions changed 
significantly), including BSS and any other relevant weather conditions 
including cloud cover, fog, sun glare, and overall visibility to the 
horizon;
    <bullet> Factors that may have contributed to impaired observations 
during each PSO shift change or as needed as environmental conditions 
changed (e.g., vessel traffic, equipment malfunctions); and
    <bullet> Survey activity information, such as acoustic source power 
output while in operation, number and volume of airguns operating in 
the array, tow depth of the array, and any other notes of significance 
(i.e., pre-clearance, ramp-up, shutdown, testing, shooting, ramp-up 
completion, end of operations, streamers, etc.).
    The following information should be recorded upon visual 
observation of any protected species:
    <bullet> Watch status (sighting made by PSO on/off effort, 
opportunistic, crew, alternate vessel/platform);
    <bullet> PSO who sighted the animal;
    <bullet> Time of sighting;
    <bullet> Vessel location at time of sighting;
    <bullet> Water depth;
    <bullet> Direction of vessel's travel (compass direction);
    <bullet> Direction of animal's travel relative to the vessel;
    <bullet> Pace of the animal;
    <bullet> Estimated distance to the animal and its heading relative 
to vessel at initial sighting;
    <bullet> Identification of the animal (e.g., genus/species, lowest 
possible taxonomic level, or unidentified) and the composition of the 
group if there is a mix of species;
    <bullet> Estimated number of animals (high/low/best);
    <bullet> Estimated number of animals by cohort (adults, yearlings, 
juveniles, calves, group composition, etc.);
    <bullet> Description (as many distinguishing features as possible 
of each individual seen, including length, shape, color, pattern, scars 
or markings, shape and size of dorsal fin, shape of head, and blow 
characteristics);
    <bullet> Detailed behavior observations (e.g., number of blows/
breaths, number of surfaces, breaching, spyhopping, diving, feeding, 
traveling; as explicit and detailed as possible; note any observed 
changes in behavior);
    <bullet> Animal's closest point of approach (CPA) and/or closest 
distance from any element of the acoustic source;
    <bullet> Platform activity at time of sighting (e.g., deploying, 
recovering, testing, shooting, data acquisition, other); and
    <bullet> Description of any actions implemented in response to the 
sighting (e.g., delays, shutdown, ramp-up) and time and location of the 
action.
    If a marine mammal is detected while using the PAM system, the 
following information should be recorded:
    <bullet> An acoustic encounter identification number, and whether 
the detection was linked with a visual sighting;
    <bullet> Date and time when first and last heard;
    <bullet> Types and nature of sounds heard (e.g., clicks, whistles, 
creaks, burst pulses, continuous, sporadic, strength of signal);
    <bullet> Any additional information recorded such as water depth of 
the hydrophone array, bearing of the animal to the vessel (if 
determinable), species or taxonomic group (if determinable), 
spectrogram screenshot, and any other notable information.
    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:
    <bullet> No mortality is anticipated or authorized;
    <bullet> The proposed activity is temporary and of relatively short 
duration (~32 days);

[[Page 30520]]

    <bullet> 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;
    <bullet> 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);
    <bullet> 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;
    <bullet> 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;
    <bullet> 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:
    <bullet> A request for renewal is received no later than 60 days 
prior to expiration of the current IHA.
    <bullet> 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.
    <bullet> 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


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