Takes of Marine Mammals Incidental To Specified Activities; Taking Marine Mammals Incidental to a Geophysical Survey in the Central Pacific Ocean, 34352-34382 [2017-15455]
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Federal Register / Vol. 82, No. 140 / Monday, July 24, 2017 / Notices
DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric
Administration
RIN 0648–XF330
Takes of Marine Mammals Incidental
To Specified Activities; Taking Marine
Mammals Incidental to a Geophysical
Survey in the Central Pacific Ocean
National Marine Fisheries
Service (NMFS), National Oceanic and
Atmospheric Administration (NOAA),
Commerce.
ACTION: Notice; proposed incidental
harassment authorization; request for
comments.
AGENCY:
NMFS has received a request
from the University of Hawaii (UH) for
authorization to take marine mammals
incidental to a marine geophysical
survey in the Central 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 August 23,
2017.
SUMMARY:
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 EastWest Highway, Silver Spring, MD 20910
and electronic comments should be sent
to ITP.Carduner@noaa.gov.
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 25megabyte 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
www.nmfs.noaa.gov/pr/permits/
incidental/research.htm without
change. All personal identifying
information (e.g., name, address)
voluntarily submitted by the commenter
may be publicly accessible. Do not
submit confidential business
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ADDRESSES:
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information or otherwise sensitive or
protected information.
FOR FURTHER INFORMATION CONTACT:
Jordan Carduner, 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:
www.nmfs.noaa.gov/pr/permits/
incidental/research.htm. 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).
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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 is preparing an Environmental
Assessment (EA) to consider the
environmental impacts associated with
the issuance of the proposed IHA.
NMFS’ EA is available at
www.nmfs.noaa.gov/pr/permits/
incidental/research.htm. 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 15, 2016, NMFS received a
request from the UH for an IHA to take
marine mammals incidental to
conducting a marine geophysical survey
in the Central Pacific Ocean. On May
16, 2017, we deemed UH’s application
for authorization to be adequate and
complete. UH’s request is for take of a
small number of 24 species of marine
mammals by Level B harassment and
Level A harassment. Neither UH nor
NMFS expects mortality to result from
this activity, 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
UH, in collaboration with the Japan
Agency for Marine-Earth Science and
Technology (JAMSTEC), proposes to
conduct a marine seismic survey north
of Hawaii in the Central Pacific Ocean
over the course of five and a half days
in September 2017. The proposed
survey would occur north of the
Hawaiian Islands, in the approximate
area 22.6–25.0° N. and 153.5–157.4° W.
(See Figure 1 in IHA application). The
project area is partly within the
exclusive economic zone (EEZ) of the
United States and partly in adjacent
international waters. Water depths in
the area range from 4000 to 5000 m. The
survey would involve one source vessel,
the Japan-flagged R/V (research vessel)
Kairei. The Kairei would deploy a 32airgun array with a total volume of
∼7800 cubic inches (in3) as an energy
source.
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Dates and Duration
The seismic survey would be carried
out for approximately five and a half
days, including three and half days
within the Hawaiian Islands EEZ and
two days in international waters. The
survey would start on approximately
September 15, 2017. Exact dates of the
activities are not known as they are
dependent on logistics and weather
conditions. Seismic activities would
occur 24 hours per day during the
proposed survey.
Specific Geographic Region
The survey would encompass the
approximate area 22.6–25.0° N. and
153.5–157.4° W. in the central Pacific
Ocean north of Hawaii, partly within
the Hawaiian Islands EEZ and partly in
international waters. Water depth in the
survey area ranges from approximately
4000 to 5000 m. Representative survey
track lines are shown in Figure 1 in the
IHA application. However, some
deviation in actual track lines could be
necessary for reasons such as poor data
quality, inclement weather, or
mechanical issues with the research
vessel and/or equipment. The Kairei
would likely depart from Honolulu,
Hawaii and return to Honolulu.
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Detailed Description of Specific Activity
Conventional seismic methodology
would be used to image a typical/stable
oceanic crust, mantle, and the boundary
between the Earth’s crust and the
ˇ ´
mantle (called the Mohorovicic
discontinuity (Moho)). The data
obtained from the survey would be used
to help better inform and further refine
planning efforts for a proposed ‘‘Project
Mohole’’ under consideration for
scheduling by the International Ocean
Discovery Program (IODP). The total
survey effort would consist of ∼1083
kilometers (km) of transect lines (Figure
1 in IHA application).
The R/V Kairei has a length of 106.0
meters (m), a beam of 16.0 m, and a
maximum draft of 4.7 m. Its propulsion
system consists of two diesel engines,
each producing 2206 kW, which drive
the two propellers at 600 revolutions
per minute (rpm). The operation speed
during seismic acquisition would be
∼8.3 km/hour (∼4.5 knots (kn)). When
not towing seismic survey gear, the
Kairei typically cruises at 30 km/hour
(∼16.2 kn) and has a range of ∼18,000
km.
During the survey, the Kairei would
deploy an airgun array (i.e., a certain
number of airguns of varying sizes in a
certain arrangement) as an energy
source (Table 1). An airgun is a device
used to emit acoustic energy pulses into
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the seafloor and generally consists of a
steel cylinder that is charged with highpressure air. Release of the compressed
air into the water column generates a
signal that reflects (or refracts) off the
seafloor and/or subsurface layers having
acoustic impedance contrast. When
fired, a brief (∼0.1 second) pulse of
sound is emitted by all airguns nearly
simultaneously. The airguns are silent
during the intervening periods with the
array typically fired on a fixed distance
(or shot point) interval. The return
signal is recorded by a listening device
and later analyzed with computer
interpretation and mapping systems
used to depict the subsurface.
The airgun array to be used would
consist of 32 Bolt Annular Port airguns,
with a total volume of ∼7800 in3. The
airguns would be configured as four
identical linear arrays or ‘‘strings’’ (See
Figure 2 in the IHA application for a
visual representation of the strings).
Each string would have 8 airguns; the
first and last airguns in the strings
would be spaced 10 m apart. All 8
airguns in each string would be fired
simultaneously. The 4 airgun strings
would be towed behind the Kairei and
would be distributed across an area ∼40
m × 10 m. The shot interval would be
∼22 seconds. The firing pressure of the
array would be ∼2000 psi. During firing,
a brief (∼0.1 s) pulse of sound would be
emitted. The airguns would be silent
during the intervening periods. The
array would be towed at a depth of 10
m. It is expected that the aigun array
would be active 24 hours per day during
seismic activities. Specifications of the
Kairei’s airgun array are shown in Table
1. Source levels of the Kairei’s airgun
array are shown in Table 6.
TABLE 1—SPECIFICATIONS OF THE R/V
KAIREI AIRGUN ARRAY
Number of airguns ....
Tow depth of energy
source.
Dominant frequency
components.
Total volume .............
Pulse duration ...........
Shot interval ..............
32.
10 meters (m).
2–120 Hz.
∼7800 in.3
∼0.1 second.
∼22 seconds.
The receiving system would consist of
one 6 km long hydrophone streamer and
ocean bottom seismometers (OBSs). As
the airgun array is towed along the
survey lines, the hydrophone streamer
would receive the returning acoustic
signals and transfer the data to the onboard processing system. The OBSs
would record the returning acoustic
signals internally for later analysis.
Upon arrival at the survey area, two
OBSs would be deployed. The streamer
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and airgun array would then be
deployed, and seismic operations would
commence. After completion of seismic
operations, the OBSs would be
recovered by UH via a separate vessel;
the recovery cruise would be funded by
the National Science Foundation.
Survey protocols generally involve a
predetermined set of survey, or track,
lines. The seismic acquisition vessel
(source vessel) travels down a linear
track for some distance until a line of
data is acquired, then turn and acquire
data on a different track. In the case of
the proposed survey, the two shorter
north-south lines would each be
surveyed once, while the longer westeast line would be surveyed twice (see
Figure 1 in the IHA application).
In addition to the operations of the
airgun array, a SeaBeam 3012
multibeam echosounder (MBES) would
also be operated from the Kairei
continuously throughout the survey.
The MBES would operate at 12 kilohertz
(kHz) and would be hull-mounted on
the Kairei. The transmitting beamwidth
of the MBES would be 2° fore–aft and
150° (max.) athwartship, or 120° (in
water up to 4500 m deep), and 100° (in
water up to 8000 m).
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 Specified Activities
Section 4 of the application
summarizes available information
regarding status and trends, distribution
and habitat preferences, and behavior
and life history, of the potentially
affected species. Additional information
regarding population trends and threats
may be found in NMFS’ Stock
Assessment Reports (SAR;
www.nmfs.noaa.gov/pr/sars/), and more
general information about these species
(e.g., physical and behavioral
descriptions) may be found on NMFS’
Web site (www.nmfs.noaa.gov/pr/
species/mammals/).
Table 2 lists all species with expected
potential for occurrence in the central
Pacific Ocean and summarizes
information related to the population or
stock, including regulatory status under
the MMPA and ESA and potential
biological removal (PBR), where known.
For taxonomy, we follow Committee on
Taxonomy (2016). PBR is defined by the
MMPA as the maximum number of
animals, not including natural
mortalities, that may be removed from a
marine mammal stock while allowing
that stock to reach or maintain its
optimum sustainable population (as
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described in NMFS’ SARs). While no
mortality is anticipated or authorized
here, PBR and annual serious injury and
mortality from anthropogenic sources
are included here as gross indicators of
the status of the species and other
threats.
Marine mammal abundance estimates
presented in this document represent
the total number of individuals that
make up a given stock or the total
number estimated within a particular
study or survey area. NMFS’ stock
abundance estimates for most species
represent the total estimate of
individuals within the geographic area,
if known, that comprises that stock. For
some species, this geographic area may
extend beyond U.S. waters. All managed
stocks in this region are assessed in
NMFS’ U.S. Pacific SARs (e.g., Carretta
et al. 2017). All values presented in
Table 2 are the most recent available at
the time of publication and are available
in the 2016 SARs (Carretta et al. 2017),
available online at: www.nmfs.noaa.gov/
pr/sars, except where noted otherwise.
TABLE 2—MARINE MAMMALS THAT COULD OCCUR IN THE PROJECT AREA
Species
Stock abundance 2
(CV, Nmin, most
recent abundance
survey) 3
ESA/MMPA
status;
strategic
(Y/N) 1
Stock
Relative
occurrence in
project area
PBR 4
Order Cetartiodactyla—Cetacea—Superfamily Mysticeti (baleen whales)
Family: Balaenopteridae
Humpback whale (Megaptera
novaeangliae) 5.
Central North Pacific.
-/-; N .......
10,103 (0.300; 7,890;
2006).
83 .........
Blue whale (Balaenoptera
musculus).
Central North Pacific.
E/D; Y ....
81 (1.14; 38; 2010) ..........
0.1 ........
Fin whale (Balaenoptera
physalus).
Sei whale (Balaenoptera borealis).
Hawaii .................
E/D; Y ....
58 (1.12; 27; 2010) ..........
0.1 ........
Hawaii .................
E/D; Y ....
178 (0.90; 93; 2010) ........
0.2 ........
Bryde’s whale (Balaenoptera
brydei/edeni).
Hawaii .................
-/-; N .......
798 (0.28; 633; 2010) ......
6.3 ........
Minke Whale (Balaenoptera
acutorostrata).
Hawaii .................
-/-; N .......
n/a (n/a; n/a; 2010) ..........
Undet. ..
Seasonal; throughout known breeding grounds during winter and
spring (most common November
through April).
Seasonal; infrequent winter migrant;
few sightings, mainly fall and winter; considered rare.
Seasonal, mainly fall and winter;
considered rare.
Rare; limited sightings of seasonal
migrants that feed at higher latitudes.
Uncommon; distributed throughout
the Hawaiian Exclusive Economic
Zone.
Seasonal, mainly fall and winter;
considered rare.
Order Cetartiodactyla—Cetacea—Superfamily Odontoceti (toothed whales, dolphins, and porpoises)
Family: Physeteridae
Sperm whale (Physeter
Hawaii ................. E/D; Y .... 3,354 (0.34; 2,539; 2010) 10.2 ...... Widely distributed year round.
macrocephalus).
Order Cetartiodactyla—Cetacea—Superfamily Odontoceti (toothed whales, dolphins, and porpoises)
Family: Kogiidae
whale 6
Pygmy sperm
(Kogia
breviceps).
Dwarf sperm whale 6 (Kogia
sima).
Hawaii .................
-/-; N .......
7,139 (2.91; n/a; 2006) ....
Undet. ..
Widely distributed year round.
Hawaii .................
-/-; N .......
17,519 (7.14; n/a; 2006) ..
Undet. ..
Widely distributed year round.
Order Cetartiodactyla—Cetacea—Superfamily Odontoceti (toothed whales, dolphins, and porpoises)
Family: Delphinidae
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Killer whale (Orcinus orca) ........
False killer whale (Pseudorca
crassidens).
Pygmy killer whale (Feresa
attenuata).
Short-finned pilot whale
(Globicephala macrorhynchus).
Hawaii .................
Hawaii Pelagic ....
-/-; N .......
-/-; N .......
101 (1.00; 50; 2010) ........
1,540 (0.66; 928; 2010) ...
1 ...........
9.3 ........
Uncommon; infrequent sightings.
Regular.
Hawaii .................
-/-; N .......
3,433 (0.52; 2,274; 2010)
23 .........
Year-round resident.
Hawaii .................
-/-; N .......
12,422 (0.43; 8,872;
2010).
70 .........
Melon headed whale
(Peponocephala electra).
Bottlenose dolphin (Tursiops
truncatus).
Pantropical spotted dolphin
(Stenella attenuata).
Striped dolphin (Stenella
coeruleoala).
Spinner dolphin 6 (Stenella
longirostris).
Rough-toothed dolphin (Steno
bredanensis).
Hawaiian Islands
-/-; N .......
5,794 (0.20; 4,904; 2010)
4 ...........
Commonly observed around Main
Hawaiian Islands and Northwestern Hawaiian Islands.
Regular.
Hawaii pelagic .....
-/-; N .......
5,950 (0.59; 3,755; 2010)
38 .........
Common in deep offshore waters.
Hawaii pelagic .....
-/-; N .......
115 .......
Hawaii .................
-/-; N .......
Hawaii pelagic .....
-/-; N .......
15,917 (0.40; 11,508;
2010).
20,650 (0.36; 15,391;
2010).
3,351 (0.74; n/a; 2006) ....
Undet. ..
Hawaii .................
-/-; N .......
6,288 (0.39; 4,581; 2010)
46 .........
Hawaii .................
-/-; N .......
16,992 (0.66; 10,241;
2010).
102 .......
Common; primary occurrence between 100 and 4,000 m depth.
Occurs regularly year round but infrequent sighting during survey.
Common year-round in offshore
waters.
Common throughout the Main Hawaiian Islands and Hawaiian Islands EEZ.
Tropical species only recently documented within Hawaiian Islands
EEZ (2002 survey).
Fraser’s dolphin (Lagenodelphis
hosei).
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154 .......
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TABLE 2—MARINE MAMMALS THAT COULD OCCUR IN THE PROJECT AREA—Continued
Stock
ESA/MMPA
status;
strategic
(Y/N) 1
Stock abundance 2
(CV, Nmin, most
recent abundance
survey) 3
PBR 4
Hawaii .................
-/-; N .......
7,256 (0.41; 5,207; 2010)
42 .........
Species
Risso’s dolphin (Grampus
griseus).
Relative
occurrence in
project area
Previously considered rare but multiple sightings in Hawaiian Islands
EEZ during various surveys conducted from 2002–2012.
Order Cetartiodactyla—Cetacea—Superfamily Odontoceti (toothed whales, dolphins, and porpoises)
Family: Ziphiidae
Cuvier’s beaked whale (Ziphius
cavirostris).
Blainville’s beaked whale
(Mesoplodon densirostris).
Longman’s beaked whale
(Indopacetus pacificus).
Hawaii .................
-/-; N .......
1,941 (n/a; 1,142; 2010) ..
11.4 ......
Hawaii .................
-/-; N .......
2,338 (1.13; 1,088; 2010)
11 .........
Hawaii .................
-/-; N .......
4,571 (0.65; 2,773; 2010)
28 .........
Year-round occurrence but difficult
to detect due to diving behavior.
Year-round occurrence but difficult
to detect due to diving behavior.
Considered rare; however, multiple
sightings during 2010 survey.
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
(see footnote 3) 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 Abundance estimates from Carretta et al. (2017) unless otherwise noted.
3 CV is coefficient of variation; N
min is the minimum estimate of stock abundance. In some cases, CV is not applicable. For certain stocks, abundance estimates
are actual counts of animals and there is no associated CV. The most recent abundance survey that is reflected in the abundance estimate is presented; there
may be more recent surveys that have not yet been incorporated into the estimate.
4 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 size (OSP).
5 Values for humpback whale are from the 2015 Alaska SAR (Muto et al. 2015).
6 Values for spinner dolphin, dwarf and pygmy sperm whale are from Barlow et al. (2006).
All species that could potentially
occur in the proposed survey area are
included in Table 2. We have reviewed
UH’s species descriptions, including life
history information, distribution,
regional distribution, diving behavior,
and acoustics and hearing, for accuracy
and completeness. We refer the reader
to Section 4 of UH’s IHA application,
rather than reprinting the information
here. Below, for the 24 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.
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Humpback Whale
Humpback whales are found
worldwide in all ocean basins. In
winter, most humpback whales occur in
the subtropical and tropical waters of
the Northern and Southern Hemispheres
(Muto et al., 2015). These wintering
grounds are used for mating, giving
birth, and nursing new calves.
Humpback whales migrate nearly 3,000
mi (4,830 km) from their winter
breeding grounds to their summer
foraging grounds in Alaska.
There are five stocks of humpback
whales, one of which occurs in Hawaii:
The Central North Pacific Stock, which
consists of winter/spring populations in
the Hawaiian Islands, which migrate
primarily to northern British Columbia/
Southeast Alaska, the Gulf of Alaska,
and the Bering Sea/Aleutian Islands
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(Muto et al., 2015). Humpback whales
occur seasonally in Hawaii, with peak
sightings between December and May
each year; however, sightings have
occurred in other months in very low
numbers. Most humpback whales
congregate off the island of Maui in the
shallow protected waters but can be
seen off all of the islands including the
Northwestern Hawaiian Islands (Baird
2016).
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. The Hawaii DPS
is the only DPS that occurs in the survey
area and is not listed under the ESA (81
FR 62259; September 8, 2016). The
Central North Pacific stock is still
considered a depleted and strategic
stock under the MMPA.
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. 2008).
Blue whale migration is less well
defined than for some other rorquals,
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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. 2000). Blue whales
belonging to the central Pacific stock
appear to feed in summer southwest of
Kamchatka, south of the Aleutians, and
in the Gulf of Alaska (Stafford 2003;
Watkins et al. 2000), and in winter
migrate to lower latitudes in the western
and central Pacific, including Hawaii
(Stafford et al. 2001).
From ship line-transect surveys, Wade
and Gerrodette (1993) estimated 1,400
blue whales for the eastern tropical
Pacific. A 2010 shipboard line-transect
survey of the entire Hawaiian Islands
EEZ resulted in a summer/fall
abundance estimate of 81 (CV = 1.14)
blue whales (Bradford et al. 2013). This
is currently the best available
abundance estimate for this stock within
the Hawaii EEZ, though the majority of
blue whales would be expected to be at
higher latitudes feeding grounds at this
time of year. Blue whales are listed as
endangered under the ESA, and the
Central North Pacific Stock of blue
whales is considered a depleted and
strategic stock under the MMPA.
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Bryde’s Whale
Fin whales are found throughout all
oceans from tropical to polar latitudes.
They have been considered rare in
Hawaiian waters and are absent to rare
in eastern tropical Pacific waters
(Hamilton 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).
During spring and summer, fin whale
occurrence in Hawaii is considered rare
(DoN 2005). There were 5 sightings of
fin whales during summer–fall surveys
in 2002, most to the northwest of the
Main Hawaiian Islands (Barlow et al.
2004) and two sightings in the Hawaiian
Islands EEZ during summer–fall 2010
(Bradford et al. 2013); there were no
sightings in or near the proposed survey
area (Carretta et al. 2015). Two
additional sightings in the EEZ were
made by observers on Hawaii-based
longline fishing vessels, including one
near the proposed survey area (Carretta
et al. 2015). Fin whales are listed as
endangered under the ESA, and the
Hawaii stock of fin whales is considered
depleted under the MMPA.
The Bryde’s whale occurs in all
tropical and warm temperate waters in
the Pacific, Atlantic, and Indian oceans,
between 40° N. and 40° S. (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 (>16 °C) water yearround (Kato and Perrin 2009).
Bryde’s whales are known to occur in
both shallow coastal and deeper
offshore waters (Jefferson et al. 2008). 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 made during 2010 (Bradford et al.
2013). 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 or near the proposed
survey area (Barlow et al. 2004; Barlow
2006; Bradford et al. 2013; Carretta et al.
2015). The Bryde’s whale is not listed
under the ESA, and the Hawaii stock is
not listed as depleted or strategic under
the MMPA.
Sei Whale
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Fin Whale
The minke whale has a cosmopolitan
distribution ranging from the tropics
and subtropics to the ice edge in both
hemispheres (Jefferson et al. 2008) and
is thought to occur seasonally in
Hawaii, from November through March
(Rankin and Barlow 2005), though their
migration routes or destinations are
unknown. While they are generally
believed to be uncommon in Hawaiian
waters, several studies using acoustic
detections suggest that minke whales
may be more common than previously
thought (Rankin et al. 2007; Oswald et
al. 2011; Martin et al. 2012). 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 (Martin et al. 2012). Passive
acoustic detections of minke whales
have been recorded at ALOHA station
(22.75° N., 158° W.) from October to
May for decades (Oswald et al. 2011). A
lack of sightings is likely related to
misidentification or low detection
capability in poor sighting conditions
The sei whale occurs in all ocean
basins (Horwood 2009) but appears to
prefer mid-latitude temperate waters
(Jefferson et al. 2008). 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).
Sei whales occur seasonally in Hawaii
in the winter and spring months and
feed in higher latitude feeding grounds
in the summer and fall (Carretta et al.,
2016). Sightings of this species are rare
in Hawaii. The species stays offshore of
the islands in deeper waters (Baird
2016). Sei whales are listed as
endangered under the ESA, and the
Hawaii stock of sei whales is considered
a depleted and strategic stock under the
MMPA.
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Minke Whale
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(Rankin et al. 2007). The minke whale
is not listed under the ESA, and the
Hawaii stock is not listed as depleted
under the MMPA.
Sperm Whale
Sperm whales are widely distributed
across the entire North Pacific and into
the southern Bering Sea in summer, but
the majority are thought to be south of
40° N. in winter (Rice 1974, 1989; Gosho
et al. 1984; Miyashita et al. 1995). The
Hawaii stock includes animals found
both within the Hawaiian Islands EEZ
and in adjacent high seas waters;
however, because data on abundance,
distribution, and human-caused impacts
are largely lacking for high seas waters,
the status of the Hawaii stock is
evaluated based on data from U.S. EEZ
waters of the Hawaiian Islands (NMFS
2005).
Sperm whales are widely distributed
in Hawaiian waters throughout the year
(Mobley et al. 2000). 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 adjacent to the
proposed survey area (Barlow et al.
2004; Barlow 2006; Bradford et al.
2013). Sperm whales are listed as
endangered under the ESA, and the
Hawaii stock is considered depleted and
strategic under the MMPA.
Pygmy Sperm Whale
Pygmy sperm whales are found in
tropical and warm-temperate waters
throughout the world (Ross and
Leatherwood 1994) and prefer deeper
waters with observations of this species
in greater than 4,000 m depth (Baird et
al., 2013). Sightings are rare of this
species. They 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 (Wursig et
al. 1998). Both pygmy and dwarf sperm
whales 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. 2008). There is a single stock of
Pygmy sperm whales in Hawaii. Current
abundance estimates for this stock are
unknown. Pygmy sperm whales are not
listed as endangered or threatened
under the ESA, and the Hawaii stock is
not considered strategic or designated as
depleted under the MMPA.
Dwarf Sperm Whale
Dwarf sperm whales are found
throughout the world in tropical to
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warm-temperate waters (Carretta et al.,
2014). They are usually found in waters
deeper than 500 m, most often sighted
in depths between 500 and 1,000 m, but
they have been documented in depths
as shallow as 106 m and as deep as
4,700 m (Baird 2016). This species is
often alone or in small groups of up to
two to four individuals (Baird 2016).
When there are more than two animals
together, they are often loosely
associated, with up to several hundred
meters between pairs of individuals
(Baird 2016). There is one stock of dwarf
sperm whales in Hawaii. Sighting data
suggests a small resident population off
Hawaii Island (Baird 2016). It has been
suggested that this species is probably
one of the more abundant species of
cetaceans in Hawaiian waters (Baird
2016), though there are no current
abundance estimates for this stock.
Dwarf sperm whales are not listed as
endangered or threatened under the
ESA, and the Hawaii stock is not
designated as depleted or strategic
under the MMPA.
Killer Whale
Killer whales have been observed in
all oceans and seas of the world
(Leatherwood and Dahlheim 1978).
Although reported from tropical and
offshore waters (Heyning and Dahlheim
1988), killer whales prefer the colder
waters of both hemispheres, with
greatest abundances found within 800
km of major continents (Mitchell 1975).
High densities of the species occur in
high latitudes, especially in areas where
prey is abundant.
Killer whales are considered rare in
Hawaiian waters (Carretta et al. 2017).
Twenty one sighting records were
reported in Hawaiian waters between
1994 and 2004 (Baird et al. 2006).
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. 2013), none near the
proposed survey area (Barlow et al.
2004; Bradford et al. 2013; Carretta et al.
2017). Numerous additional sightings in
and north of the EEZ have been made
by observers on longliners, some in and
near the proposed survey area (Carretta
et al. 2017). Killer whales are not listed
as endangered or threatened under the
ESA (with the exception of the
endangered Southern Resident DPS
which does not occur in the survey
area), and the Hawaii stock is not
designated as depleted or strategic
under the MMPA.
False Killer Whale
False killer whales are found
worldwide in tropical and warm-
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temperate waters (Stacey et al. 1994). In
the North Pacific, this species is well
known from southern Japan, Hawaii,
and the eastern tropical Pacific. The
species 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).
Telemetry, photo-identification, and
genetic studies have identified three
independent populations of false killer
whales in Hawaiian waters: Main
(insular) Hawaiian Islands,
Northwestern Hawaiian Islands, and
surrounding pelagic stock (Chivers et al.
2010; Baird et al. 2010, 2013; Bradford
et al. 2014). Based on the ranges of these
stocks, only the Hawaii pelagic stock is
expected to occur in the survey area
(Carretta et al. 2017). False killer whales
are not listed as endangered or
threatened under the ESA (with the
exception of the endangered Main
Hawaiian Islands insular DPS which
does not occur in the survey area), and
the Hawaii pelagic stock is not
designated as depleted or strategic
under the MMPA.
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° S. (Jefferson et al. 2008). In
warmer water, it is usually seen close to
the coast (Wade and Gerrodette 1993),
but it is also found in deep waters. In
Hawaiian waters, the pygmy killer
whale is found in nearshore waters but
rarely offshore (Carretta et al. 2015).
During small-boat surveys around the
Hawaiian Islands in 2000–2012,
sightings were made in water up to
3,000 m deep (Baird et al. 2013).
Though a small resident population
occurs in the main Hawaiian Islands,
pygmy killer whales are relatively rare
in Hawaiian waters (McSweeney et al.
2009). Satellite telemetry data from four
tagged pygmy killer whales suggest the
resident group remains within 20 km of
shore (Baird et al. 2011) so would be
unlikely in the proposed survey area.
Movements have been documented
between Hawaii Island and Oahu and
between Oahu and Lanai (Baird et al.
2011a). Pygmy killer whales are not
listed under the ESA, and the Hawaii
stock is not listed as is not considered
a depleted or strategic stock under the
MMPA.
Short-Finned Pilot Whale
Short-finned pilot whales are found in
all oceans, primarily in tropical and
warm-temperate waters (Carretta et al.,
2016). The species prefers deeper
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34357
waters, ranging from 324 m to 4,400 m,
with most sightings between 500 m and
3,000 m (Baird 2016). This stock forms
stable social groups, with average group
size of 18 individuals but may form
large aggregations of close to 200
individuals (Baird 2016). Other research
suggests a larger average group size of
40.9 individuals (Bradford et al., 2017),
but most of these sightings were farther
offshore in pelagic waters.
Short-finned pilot whales are
commonly observed around the main
Hawaiian Islands and are also present
around the Northwestern Hawaiian
Islands (Shallenberger 1981, Baird et al.
2013). Photo-identification and
telemetry studies suggest there may be
inshore and pelagic populations of short
finned pilot whales in Hawaiian waters.
Resighting and social network analyses
of individuals photographed off Hawaii
Island suggest the occurrence of one
large and several smaller social clusters
that use those waters, with some
individuals within the smaller social
clusters commonly resighted off Hawaii
Island (Mahaffy 2012). Short-finned
pilot whales are not listed as
endangered or threatened under the
ESA, and the Hawaii stock is not
considered a depleted or strategic stock
under the MMPA.
Melon-Headed Whale
Melon-headed whales are found in
tropical and warm-temperate waters
throughout the world (Carretta et al.,
2016). The distribution of reported
sightings suggests that the oceanic
habitat of this species is primarily
equatorial waters (Perryman et al. 1994).
The species forms large groups, with
average group size of almost 250
individuals, with the largest group
documented at close to 800 individuals
(Baird 2016).
There are two demographicallyindependent populations in Hawaiian
waters, the Hawaiian Islands stock and
the Kohala resident stock (Carretta et al.,
2016). The Kohala resident stock have a
small range restricted to the shallow
waters around Hawaii Island, whereas
the Hawaiian Islands stock are found
throughout the islands and offshore in
pelagic areas (Carretta et al., 2016). As
such, only the Hawaiian Islands stock
may be affected by the proposed
activities. This stock prefers waters
deeper than 1,000 m (Baird 2016).
Satellite telemetry data revealed distant
pelagic movements, associated with
feeding, nearly to the edge of the
Hawaiian Islands EEZ; the most distal
telemetry locations were near the
proposed survey area at ∼22.3° N.,
154.0° W. (Oleson et al. 2013). Melonheaded whales are not listed as
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endangered or threatened under the
ESA and the Hawaiian Islands stock is
not considered a depleted or strategic
stock under the MMPA.
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Bottlenose Dolphin
Bottlenose dolphins are widely
distributed throughout the world in
tropical and warm-temperate waters
(Perrin et al. 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).
There are four resident insular stocks
of bottlenose dolphins around the Main
Hawaiian Islands and one pelagic stock
(Carretta et al., 2016). Photoidentification studies have suggested
that the 1,000-m isobath serves as the
boundary between resident insular
stocks of the Main Hawaiian Islands and
the Hawaii pelagic stock (Martien et al.
2012). Only the pelagic stock may be
affected by the proposed activity.
Bottlenose dolphins are not listed as
endangered or threatened under the
ESA, and the Hawaii pelagic stock is not
considered a depleted or strategic stock
under the MMPA.
Pantropical Spotted Dolphin
Pantropical spotted dolphins are
primarily found in tropical and
subtropical waters worldwide (Perrin et
al. 2009). There are two forms of
pantropical spotted dolphin: Coastal
and offshore. Pantropical spotted
dolphins prefer deeper waters between
1,500 m and 3,000 m and forms large
groups with average group size of 60
individuals, with the largest group
estimated at 400 individuals (Baird
2016).
Pantropical spotted dolphins are
common and abundant throughout the
Hawaiian archipelago (Baird et al.
2013). It is expected that it would be
one of the most abundant cetaceans in
the proposed survey area. There are four
resident coastal stocks in Hawaii in
addition to the Hawaii pelagic stock.
Due to their ranges, only the pelagic
stock is likely to be encountered in the
project area (Carretta et al., 2016).
Pantropical spotted dolphins are not
listed as endangered or threatened
under the ESA, and the Hawaii pelagic
stock is not considered a depleted or
strategic stock under the MMPA.
Striped Dolphin
Striped dolphins are found in tropical
to warm-temperate waters throughout
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the world (Carretta et al., 2016). This is
a deep water species, preferring depths
greater than 3,500 m (Baird 2016).
Striped dolphins occur primarily in
pelagic waters, but have been observed
approaching shore where there is deep
water close to the coast (Jefferson et al.
2008). This species forms large groups,
with an average group size of 28
individuals, and a maximum group size
of 100 individuals (Baird 2016).
The striped dolphin is expected to be
one of the most abundant cetaceans in
the proposed survey area. It has been
sighted near the proposed survey area
during summer–fall shipboard surveys
of the Hawaii Islands EEZ (Carretta et al.
2017). Striped dolphins are not listed as
endangered or threatened under the
ESA, and the Hawaii stock of striped
dolphins is not considered a depleted or
strategic stock under the MMPA.
Spinner Dolphin
Spinner dolphins are found in
tropical and warm-temperate waters
worldwide (Carretta et al., 2016). They
are pantropical in distribution,
including oceanic tropical and subtropical waters between 40° N. and 40°
S. (Jefferson et al., 2008). Generally
considered a pelagic species (Perrin
2009b), spinner dolphins can also be
found in coastal waters and around
oceanic islands (Rice 1998). There are
six separate stocks managed within the
Hawaiian Islands EEZ (Carretta et al.
2017); only individuals of the Hawaii
pelagic stock are expected to overlap
with the proposed survey area. Spinner
dolphins have been sighted near the
proposed survey area during summer–
fall surveys of the Hawaiian Islands EEZ
(Carretta et al. 2017). The spinner
dolphin is not listed as endangered or
threatened under the ESA, and the
Hawaii pelagic stock is not considered
a depleted or strategic stock under the
MMPA.
Rough-Toothed Dolphin
Rough-toothed dolphins are found in
tropical and warm-temperate waters
(Carretta et al., 2016). While there is
evidence for two island-associated
stocks and one pelagic stock in Hawaii,
there is only one stock designated for
Hawaii (Carretta et al., 2016). Most
sightings of this species off Kauai are in
water depths of less than 1,000 m;
however, it is the most often sighted
species in depths greater than 3,000 m
(Baird 2016). This species forms stable
associations as part of larger groups,
with average group sizes of 11 animals
and maximum group sizes, observed off
Kauai, of 140 individuals (Baird 2016).
The rough-toothed dolphin is
expected to be one of the most abundant
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cetaceans in the proposed survey area
(Barlow et al. 2004; Barlow 2006;
Bradford et al. 2013). During summer–
fall surveys of the Hawaiian Islands EEZ
in 2002 and 2010, rough-toothed
dolphins were observed throughout the
EEZ and near the proposed survey area.
The rough-toothed dolphin is not listed
as endangered or threatened under the
ESA, and the Hawaii stock is not
considered a depleted or strategic stock
under the MMPA.
Fraser’s Dolphin
Fraser’s dolphin are found in tropical
waters (Carretta et al., 2011). This is a
deep water species occurring offshore of
the Hawaiian islands, with sightings
occurring in water depths between
1,515 m and 4,600 m (Baird 2016). The
species forms large groups with average
group sizes between 75 and 110
individuals (Baird 2016). Fraser’s
dolphin is one of the most abundant
cetaceans in the Hawaiian Islands EEZ
(Barlow 2006; Bradford et al. 2013).
Fraser’s dolphin is not listed as
endangered or threatened under the
ESA, and the Hawaii stock is not
considered a depleted or strategic stock
under the MMPA.
Risso’s Dolphin
Risso’s dolphins are found in tropical
to warm-temperate waters (Carretta et
al., 2016). The species occurs from
coastal to deep water but is most often
found in depths greater than 3,000 m
with the highest sighting rate in depths
greater than 4,500 m (Baird 2016). It
occurs between 60° N. and 60° S. where
surface water temperatures are at least
10ßC (Kruse et al. 1999). The species
forms small groups with an average
group size of 4 individuals, and a
maximum group size of 25 individuals
off the coast of Hawaii (Baird 2016).
Risso’s dolphins are not listed as
endangered or threatened under the
ESA, and the Hawaii stock is not
considered a depleted or strategic stock
under the MMPA.
Longman’s Beaked Whale
The Longman’s beaked whale, also
known as Indo-Pacific beaked whale, is
considered one of the least known
cetacean species (Carretta et al., 2016).
Longman’s beaked whales are found in
tropical waters from the eastern Pacific
westward through the Indian Ocean to
the eastern coast of Africa (Carretta et
al., 2016). The species occurs is most
often sighted in waters with
temperatures ≥26° C and depth >2,000
m, and sightings have also been
reported along the continental slope
(Anderson et al. 2006; Pitman 2009).
Group sizes range from 18 to 110
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individuals (Baird 2016). The
Longman’s beaked whale is not listed as
endangered or threatened under the
ESA, and the Hawaii stock is not
considered a depleted or strategic stock
under the MMPA.
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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 found in
deep water over and near the
continental slope (Jefferson et al. 2008).
In the eastern tropical Pacific, the mean
water depth for sighted Cuvier’s beaked
whales was ∼3.4 km (Ferguson et al.
2006). During small-boat surveys around
the Hawaiian Islands in 2000–2012,
sightings were made in water depths of
500–4000 m (Baird et al. 2013).
Summer/fall shipboard surveys of the
waters within the U.S. EEZ of the
Hawaiian Islands resulted in 4 sightings
in 2002 and 22 in 2010, including
markedly higher sighting rates during
nearshore surveys in the Northwestern
Hawaiian Islands. (Barlow 2006,
Bradford et al. 2013). Resighting and
movement data of individual Cuvier’s
beaked whales suggest the existence of
insular and offshore populations of this
species in Hawaiian waters. A 21-yr
study off Hawaii Island suggests longterm site fidelity and year-round
occurrence (McSweeney et al. 2007).
The Cuvier’s beaked whale is not listed
as endangered or threatened under the
ESA, and the Hawaii stock is not
considered a depleted or strategic stock
under the MMPA.
Blainville’s Beaked Whale
Blainville’s beaked whale is found in
tropical and warm temperate waters of
all oceans; it has the widest distribution
throughout the world of all
mesoplodont species and appears to be
common (Pitman 2009b). Recent
analysis of Blainville’s beaked whale
resightings and movements near the
main Hawaiian Islands suggest the
existence of insular and pelagic
populations of this species in Hawaiian
waters (McSweeney et al. 2007, Schorr
et al. 2009, Baird et al. 2013). Photoidentification of individual Blainville’s
beaked whales from Hawaii Island since
1986 reveal repeated use of this area by
individuals for over 17 years (Baird et
al. 2011) and 75% of individuals seen
off Hawaii Island link by association
into a single social network (Baird et al.
2013). Those individuals seen farthest
from shore and in deep water (≤2100m)
have not been resighted, suggesting they
may be part of an offshore, pelagic
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population (Baird et al. 2011). The
Hawaii stock of Blainville’s beaked
whales includes animals found both
within the Hawaiian Islands EEZ and in
adjacent high seas waters. The
Blainville’s beaked whale is not listed as
endangered or threatened under the
ESA, and the Hawaii stock is not
considered a depleted or strategic stock
under the MMPA.
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 hertz
(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 (mPa)) and is a
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34359
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
(referenced to 1 mPa) while the received
level is the SPL at the listener’s position
(referenced to 1 mPa).
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 mPa2-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
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point (Richardson et al., 1995), and the
sound level of a region is defined by the
total acoustical energy being generated
by known and unknown sources. These
sources may include physical (e.g.,
wind and waves, earthquakes, ice,
atmospheric sound), biological (e.g.,
sounds produced by marine mammals,
fish, and invertebrates), and
anthropogenic (e.g., vessels, dredging,
construction) sound. A number of
sources contribute to ambient sound,
including the following (Richardson et
al., 1995):
• Wind and waves: The complex
interactions between wind and water
surface, including processes such as
breaking waves and wave-induced
bubble oscillations and cavitation, are a
main source of naturally occurring
ambient sound for frequencies between
200 Hz and 50 kHz (Mitson, 1995). In
general, ambient sound levels tend to
increase with increasing wind speed
and wave height. Surf sound becomes
important near shore, with
measurements collected at a distance of
8.5 km from shore showing an increase
of 10 dB in the 100 to 700 Hz band
during heavy surf conditions.
• Precipitation: Sound from rain and
hail impacting the water surface can
become an important component of total
sound at frequencies above 500 Hz, and
possibly down to 100 Hz during quiet
times.
• Biological: Marine mammals can
contribute significantly to ambient
sound levels, as can some fish and
snapping shrimp. The frequency band
for biological contributions is from
approximately 12 Hz to over 100 kHz.
• Anthropogenic: Sources of ambient
sound related to human activity include
transportation (surface vessels),
dredging and construction, oil and gas
drilling and production, seismic
surveys, sonar, explosions, and ocean
acoustic studies. Vessel noise typically
dominates the total ambient sound for
frequencies between 20 and 300 Hz. In
general, the frequencies of
anthropogenic sounds are below 1 kHz
and, if higher frequency sound levels
are created, they attenuate rapidly.
Sound from identifiable anthropogenic
sources other than the activity of
interest (e.g., a passing vessel) is
sometimes termed background sound, as
opposed to ambient sound.
The sum of the various natural and
anthropogenic sound sources at any
given location and time—which
comprise ‘‘ambient’’ or ‘‘background’’
sound—depends not only on the source
levels (as determined by current
weather conditions and levels of
biological and human activity) but also
on the ability of sound to propagate
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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 nonpulsed 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.
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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
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 SeaBeam 3012
MBES would also be operated from the
Kairei continuously throughout the
survey. Due to the lower source level of
the MBES relative to the Kairei’s airgun
array (241 dB re 1 mPa · m for the MBES
versus 259 dB re 1 mPa · m (rms) for the
airgun array), the sounds from the
MBES are expected to be effectively
subsumed by the sounds from the
airgun array. In addition, given the
movement and speed of the vessel, the
intermittent and narrow downwarddirected 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. For these
reasons, any marine mammal that was
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. As such, the MBES is not
expected to result in the take of any
marine mammal that has not already
been taken by the sounds from the
airgun array, and therefore we do not
consider noise from the MBES further in
this analysis.
Acoustic Effects
Here, we first provide background
information on marine mammal hearing
before discussing the potential effects of
the use of active acoustic sources on
marine mammals.
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
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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 lowfrequency cetaceans where the lower
bound was deemed to be biologically
implausible and the lower bound from
Southall et al. (2007) retained. Pinniped
functional hearing is not discussed here,
as no pinnipeds are expected to be
affected by the specified activity. The
functional groups and the associated
frequencies are indicated below (note
that these frequency ranges correspond
to the range for the composite group,
with the entire range not necessarily
reflecting the capabilities of every
species within that group):
• Low-frequency cetaceans
(mysticetes): Generalized hearing is
estimated to occur between
approximately 7 Hz and 35 kHz, with
best hearing estimated to be from 100
Hz to 8 kHz;
• Mid-frequency cetaceans (larger
toothed whales, beaked whales, and
most delphinids): Generalized hearing is
estimated to occur between
approximately 150 Hz and 160 kHz,
with best hearing from 10 to less than
100 kHz;
• High-frequency cetaceans
(porpoises, river dolphins, and members
of the genera Kogia and
Cephalorhynchus; including two
members of the genus Lagenorhynchus,
on the basis of recent echolocation data
and genetic data): Generalized hearing
is estimated to occur between
approximately 275 Hz and 160 kHz.
TABLE 3—MARINE FUNCTIONAL MAMMAL HEARING GROUPS AND THEIR
GENERALIZED HEARING RANGES
Hearing group
Low frequency (LF)
cetaceans (baleen
whales).
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Generalized hearing
range *
7 Hz to 35 kHz.
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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
Generalized hearing
Hearing group
following: Temporary or permanent
range *
hearing impairment, non-auditory
Mid-frequency (MF)
150 Hz to 160 kHz.
physical or physiological effects,
cetaceans (dolbehavioral disturbance, stress, and
phins, toothed
masking (Richardson et al., 1995;
whales, beaked
Gordon et al., 2004; Nowacek et al.,
whales, bottlenose
¨
2007; Southall et al., 2007; Gotz et al.,
whales).
2009). The degree of effect is
High-frequency (HF)
275 Hz to 160 kHz.
intrinsically related to the signal
cetaceans (true
characteristics, received level, distance
porpoises, Kogia,
from the source, and duration of the
river dolphins,
cephalorhynchid,
sound exposure. In general, sudden,
Lagenorhynchus
high level sounds can cause hearing
cruciger and L.
loss, as can longer exposures to lower
australis).
level sounds. Temporary or permanent
Phocid pinnipeds
50 Hz to 86 kHz.
loss of hearing will occur almost
(PW) (underwater)
exclusively for noise within an animal’s
(true seals).
hearing range. We first describe specific
Otariid pinnipeds
60 Hz to 39 kHz.
manifestations of acoustic effects before
(OW) (underwater)
providing discussion specific to the use
(sea lions and fur
of airgun arrays.
seals).
Richardson et al. (1995) described
* Represents the generalized hearing range zones of increasing intensity of effect
for the entire group as a composite (i.e., all
species within the group), where individual that might be expected to occur, in
species’ hearing ranges are typically not as relation to distance from a source and
broad. Generalized hearing range chosen assuming that the signal is within an
based on ∼65 dB threshold from normalized animal’s hearing range. First is the area
composite audiogram, with the exception for
lower limits for LF cetaceans (Southall et al., within which the acoustic signal would
be audible (potentially perceived) to the
2007) and PW pinniped (approximation).
animal, but not strong enough to elicit
For more detail concerning these
any overt behavioral or physiological
groups and associated frequency ranges, response. The next zone corresponds
please see NMFS (2016) for a review of
with the area where the signal is audible
available information. Twenty four
to the animal and of sufficient intensity
marine mammal species (all cetaceans)
to elicit behavioral or physiological
have the reasonable potential to coresponsiveness. Third is a zone within
occur with the proposed survey
which, for signals of high intensity, the
activities. Please refer to Table 2. Of the received level is sufficient to potentially
cetacean species that may be present,
cause discomfort or tissue damage to
six are classified as low-frequency
auditory or other systems. Overlaying
cetaceans (i.e., all mysticete species), 16 these zones to a certain extent is the
are classified as mid-frequency
area within which masking (i.e., when a
cetaceans (i.e., all delphinid and ziphiid sound interferes with or masks the
species and the sperm whale), and two
ability of an animal to detect a signal of
are classified as high-frequency
interest that is above the absolute
cetaceans (i.e., Kogia spp.).
hearing threshold) may occur; the
Potential Effects of Underwater
masking zone may be highly variable in
Sound—Please refer to the information
size.
given previously (‘‘Description of Active
We describe the more severe effects
Acoustic Sources’’) regarding sound,
certain non-auditory physical or
characteristics of sound types, and
physiological effects only briefly as we
metrics used in this document. Note
do not expect that use of airgun arrays
that, in the following discussion, we
are reasonably likely to result in such
refer in many cases to a recent review
effects (see below for further
article concerning studies of noisediscussion). Potential effects from
induced hearing loss conducted from
impulsive sound sources can range in
1996–2015 (i.e., Finneran, 2015). For
severity from effects such as behavioral
study-specific citations, please see that
disturbance or tactile perception to
work. Anthropogenic sounds cover a
physical discomfort, slight injury of the
broad range of frequencies and sound
internal organs and the auditory system,
levels and can have a range of highly
or mortality (Yelverton et al., 1973).
variable impacts on marine life, from
Non-auditory physiological effects or
none or minor to potentially severe
injuries that theoretically might occur in
TABLE 3—MARINE FUNCTIONAL MAMMAL HEARING GROUPS AND THEIR
GENERALIZED HEARING RANGES—
Continued
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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 midfrequency tactical sonar that are
associated with these types of effects.
1. 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
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 peakpressure basis and PTS cumulative
sound exposure level thresholds are 15
to 20 dB higher than TTS cumulative
sound exposure level thresholds
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(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
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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).
2. 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
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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).
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
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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 phasein 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
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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
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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 mPa2-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
significantly at onset of airgun use at
sites with a median distance of 41–45
km from the survey. Blackwell et al.
(2015) expanded this analysis to show
that whales actually increased calling
rates as soon as airgun signals were
detectable before ultimately decreasing
calling rates at higher received levels
(i.e., 10-minute SELcum of ∼127 dB).
Overall, these results suggest that
bowhead whales may adjust their vocal
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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
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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 fiveday 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
in3 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
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(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.
3. 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-pituitaryadrenal 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
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
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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).
4. 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
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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 highfrequency 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.
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
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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
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 Kairei travels at a speed of ∼8.3
km/hour while towing seismic survey
gear (LGL 2017). 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)
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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). Commercial
fishing vessels were responsible for
three percent of recorded collisions,
while 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 × 10¥6;
95% CI = 0 ¥5.5 × 10¥6; NMFS, 2013b).
In addition, a research vessel reported a
fatal strike in 2011 of a dolphin in the
Atlantic, demonstrating that it is
possible for strikes involving smaller
cetaceans to occur. In that case, the
incident report indicated that an animal
apparently was struck by the vessel’s
propeller as it was intentionally
swimming near the vessel. While
indicative of the type of unusual events
that cannot be ruled out, neither of these
instances represents a circumstance that
would be considered reasonably
foreseeable or that would be considered
preventable.
Although the likelihood of the vessel
striking a marine mammal is low, we
require a robust ship strike avoidance
protocol (see ‘‘Proposed Mitigation’’),
which we believe eliminates any
foreseeable risk of ship strike. We
anticipate that vessel collisions
involving a seismic data acquisition
vessel towing gear, while not
impossible, represent unlikely,
unpredictable events for which there are
no preventive measures. Given the
required mitigation measures, the
relatively slow speed of the vessel
towing gear, the presence of bridge crew
watching for obstacles at all times
(including marine mammals), the
presence of marine mammal observers,
and the short duration of the survey (5.5
days), 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
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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, although one
stranding event was associated with the
use of seismic airguns. This event
occurred in the Gulf of California,
coincident with seismic reflection
profiling by the R/V Maurice Ewing
operated by Columbia University’s
Lamont-Doherty Earth Observatory and
involved two Cuvier’s beaked whales
(Hildebrand, 2004). The vessel had been
firing an array of 20 airguns with a total
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volume of 8,500 in3 (Hildebrand, 2004;
Taylor et al., 2004). 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 highintensity 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 survey to
result in marine mammal stranding and
have concluded that, based on the best
available information, stranding is not
expected to occur.
Other Potential Impacts—Here, we
briefly address the potential risks due to
entanglement and contaminant spills.
We are not aware of any records of
marine mammal entanglement in towed
arrays such as those considered here.
The discharge of trash and debris is
prohibited (33 CFR 151.51–77) unless it
is passed through a machine that breaks
up solids such that they can pass
through a 25-mm mesh screen. All other
trash and debris must be returned to
shore for proper disposal with
municipal and solid waste. Some
personal items may be accidentally lost
overboard. However, U.S. Coast Guard
and Environmental Protection Act
regulations require operators to become
proactive in avoiding accidental loss of
solid waste items by developing waste
management plans, posting
informational placards, manifesting
trash sent to shore, and using special
precautions such as covering outside
trash bins to prevent accidental loss of
solid waste. There are no meaningful
entanglement risks posed by the
described activity, and entanglement
risks are not discussed further in this
document.
Marine mammals could be affected by
accidentally spilled diesel fuel from a
vessel associated with proposed survey
activities. Quantities of diesel fuel on
the sea surface may affect marine
mammals through various pathways:
surface contact of the fuel with skin and
other mucous membranes, inhalation of
concentrated petroleum vapors, or
ingestion of the fuel (direct ingestion or
by the ingestion of oiled prey) (e.g.,
Geraci and St. Aubin, 1980, 1985, 1990).
However, the likelihood of a fuel spill
during any particular geophysical
survey is considered to be remote, and
the potential for impacts to marine
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mammals would depend greatly on the
size and location of a spill and
meteorological conditions at the time of
the spill. Spilled fuel would rapidly
spread to a layer of varying thickness
and break up into narrow bands or
windrows parallel to the wind direction.
The rate at which the fuel spreads
would be determined by the prevailing
conditions such as temperature, water
currents, tidal streams, and wind
speeds. Lighter, volatile components of
the fuel would evaporate to the
atmosphere almost completely in a few
days. Evaporation rate may increase as
the fuel spreads because of the
increased surface area of the slick.
Rougher seas, high wind speeds, and
high temperatures also tend to increase
the rate of evaporation and the
proportion of fuel lost by this process
(Scholz et al., 1999). We do not
anticipate potentially meaningful effects
to marine mammals as a result of any
contaminant spill resulting from the
proposed survey activities, and
contaminant spills are not discussed
further in this document.
Anticipated Effects on Marine Mammal
Habitat
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
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
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a 150 inch3 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 survey
would occur over a relatively short time
period (5.5 days) and would occur over
a very small area relative to the area
available as marine mammal habitat in
the central Pacific Ocean. We do not
have any information to suggest the
proposed survey area represents a
significant feeding area for any marine
mammal, and 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 habitatmediated effects to marine mammals
(please see also the previous discussion
on masking under ‘‘Acoustic Effects’’),
which may range from local effects for
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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,
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nursing, breeding, feeding, or sheltering
(Level B harassment).
Authorized takes would primarily be
by Level B harassment, as use of the
seismic airguns have the potential to
result in disruption of behavioral
patterns for individual marine
mammals. There is also some potential
for auditory injury (Level A harassment)
to result, primarily for mysticetes and
high frequency cetaceans (i.e., kogiidae
spp.), due to larger predicted auditory
injury zones for those functional hearing
groups. Auditory injury is unlikely to
occur for mid-frequency species given
very small modeled zones of injury for
those species. The proposed mitigation
and monitoring measures are expected
to minimize the severity of such taking
to the extent practicable.
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
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,
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behavioral context) and can be difficult
to predict (Southall et al., 2007, Ellison
et al., 2011). 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 120 dB re
1 mPa (rms) for continuous (e.g.,
vibratory pile-driving, drilling) and
above 160 dB re 1 mPa (rms) for nonexplosive impulsive (e.g., seismic
airguns) or intermittent (e.g., scientific
sonar) sources. UH’s proposed activity
includes the use of impulsive seismic
sources. Therefore, the 160 dB re 1 mPa
(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 nonimpulsive). 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 4
below. The references, analysis, and
methodology used in the development
of the thresholds are described in NMFS
2016 Technical Guidance, which may
be accessed at: https://
www.nmfs.noaa.gov/pr/acoustics/
guidelines.htm. As described above,
UH’s proposed activity includes the use
of intermittent and impulsive seismic
sources.
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TABLE 4—THRESHOLDS IDENTIFYING THE ONSET OF PERMANENT THRESHOLD SHIFT IN MARINE MAMMALS
PTS onset thresholds
Hearing group
Impulsive*
Low-Frequency (LF) Cetaceans .............................................
Mid-Frequency (MF) Cetaceans .............................................
High-Frequency (HF) Cetaceans ............................................
Non-impulsive
Lpk,flat: 219 dB ........................................
LE,LF,24h: 183 dB
Lpk,flat: 230 dB ........................................
LE,MF,24h: 185 dB
Lpk,flat: 202 dB ........................................
LE, HF,24h: 155 dB
LE,LF,24h: 199 dB
LE,
MF,24h:
198 dB
LE,HF,24h: 173 dB
Note: * Dual metric acoustic thresholds for impulsive sounds: Use whichever results in the largest isopleth for calculating PTS onset. If a nonimpulsive 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 μPa, and cumulative sound exposure level (LE) has a reference value of 1μPa2s.
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.
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Ensonified Area
Here, we describe operational and
environmental parameters of the activity
that will feed into estimating the area
ensonified above the acoustic
thresholds.
The proposed survey would entail use
of a 32-airgun array with a total
discharge of 7,800 in3 at a tow depth of
10 m. The distance to the predicted
isopleth corresponding to the threshold
for Level B harassment (160 dB re 1 mPa)
was calculated based on results of
modeling performed by Lamont-Doherty
Earth Observatory (LDEO) of Columbia
University. Received sound levels were
predicted by LDEO’s model (Diebold et
al. 2010) as a function of distance from
the full 32-airgun array as well as for a
single 100 in3 airgun, which would be
used during power-downs. The LDEO
modeling approach uses ray tracing for
the direct wave traveling from the array
to the receiver and its associated source
ghost (reflection at the air-water
interface in the vicinity of the array), in
a constant-velocity half-space (infinite
homogeneous ocean layer unbounded
by a seafloor). LDEO’s modeling
methodology is described in greater
detail in the IHA application (LGL 2017)
and we refer to the reader to that
document rather than repeating it here.
The estimated distances to the Level B
harassment isopleth for the Kairei’s full
airgun array and for the single 100-in3
airgun are shown in Table 5.
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TABLE 5—PREDICTED RADIAL DISTANCES FROM R/V KAIREI SEISMIC
TO
ISOPLETH
CORSOURCE
RESPONDING TO LEVEL B HARASSMENT THRESHOLD
Source and volume (in3)
1 airgun, 100 ....................
4 strings, 32 airguns,
7,800.
Predicted
distance to
threshold (160
dB re 1 μPa)
(m)
722
9,289
Predicted distances to Level A
harassment isopleths, which vary based
on marine mammal hearing groups
(Table 3), were calculated based on
modeling performed by LDEO using the
Nucleus software program and the
NMFS User Spreadsheet, described
below. The updated acoustic thresholds
for impulsive sounds (such as airguns)
contained in the Technical Guidance
(NMFS 2016) were presented as dual
metric acoustic thresholds using both
SELcum and peak sound pressure
metrics. As dual metrics, NMFS
considers onset of PTS (Level A
harassment) to have occurred when
either one of the two metrics is
exceeded (i.e., metric resulting in the
largest isopleth). The SELcum metric
considers both level and duration of
exposure, as well as auditory weighting
functions by marine mammal hearing
group. In recognition of the fact that the
requirement to calculate Level A
harassment ensonified areas could be
more technically challenging to predict
due to the duration component and the
use of weighting functions in the new
SELcum thresholds, NMFS developed an
optional User Spreadsheet that includes
tools to help predict a simple isopleth
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that can be used in conjunction with
marine mammal density or occurrence
to facilitate the estimation of take
numbers.
The values for SELcum and peak SPL
for the Kairei airgun array were derived
from calculating the modified farfield
signature (Table 6). 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
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sound sources, such as airgun arrays.
UH used the acoustic modeling
developed by LDEO (same as used for
Level B takes) with a small grid step of
1 m in both the inline and depth
directions (for example, see Figure 5 in
the IHA application). 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.
TABLE 6—MODELED SOURCE LEVELS FOR R/V KAIREI 7,800 IN 3 AIRGUN ARRAY AND 100 IN 3 AIRGUN BASED ON
MODIFIED FARFIELD SIGNATURE
7,800 in 3
airgun array
(Peak SPLflat)
(db)
Functional hearing group
Low frequency cetaceans ................................................................................
(Lpk,flat: 219 dB; LE,LF,24h: 183 dB) ..................................................................
Mid frequency cetaceans .................................................................................
(Lpk,flat: 230 dB; LE,MF,24h: 185 dB) ..................................................................
High frequency cetaceans ...............................................................................
(Lpk,flat: 202 dB; LE,HF,24h: 155 dB) ..................................................................
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 Kairei’s airgun
array (modeled in 1 Hz bands) was used
to make adjustments (dB) to the
unweighted spectrum levels, by
frequency, according to the weighting
functions for each relevant marine
mammal hearing group. These adjusted/
weighted spectrum levels were then
converted to pressures (micropascals) in
order to integrate them over the entire
broadband spectrum, resulting in
broadband weighted source levels by
7,800 in 3
airgun array
(SELcum)
(db)
100 in 3 airgun
(Peak SPLflat)
(db)
100 in 3 airgun
(SELcum)
(db)
256.36
235.01
229.46
208.41
245.59
235.12
229.47
208.44
256.26
235.16
229.59
209.01
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, a source velocity
of 2.315 meters/second, and shot
interval of 21.59 seconds (LGL 2017),
potential radial distances to auditory
injury zones were then calculated for
SELcum thresholds. To estimate Peak
SPL thresholds, modeling was run for a
single shot and then a high pass filter
was applied for each hearing group. A
high pass filter is a type of band bandpass filter, which pass frequencies
within a defined range without reducing
amplitude and attenuate frequencies
outside that defined range (Yost 2007).
Inputs to the User Spreadsheet are
shown in Table 6; outputs from the User
Spreadsheet in the form of estimated
distances to Level A harassment
isopleths are shown in Table 7. The
User Spreadsheet used by UH is shown
in Table 3 of the IHA application.
TABLE 7—MODELED RADIAL DISTANCES FROM R/V KAIREI 7800 IN3 AIRGUN ARRAY AND 100 IN3 AIRGUN TO ISOPLETHS
CORRESPONDING TO LEVEL A HARASSMENT THRESHOLDS
7,800 in3
airgun array
(peak SPLflat)
(m)
Functional hearing group
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Low frequency cetaceans ................................................................................
(Lpk,flat: 219 dB; LE,LF,24h: 183 dB) ..................................................................
Mid frequency cetaceans .................................................................................
(Lpk,flat: 230 dB; LE,MF,24h: 185 dB) ..................................................................
High frequency cetaceans ...............................................................................
(Lpk,flat: 202 dB; LE,HF,24h: 155 dB) ..................................................................
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 take. However,
these tools offer the best way to predict
appropriate isopleths when more
sophisticated 3D modeling methods are
not available, and NMFS continues to
develop ways to quantitatively refine
these tools and will qualitatively
address the output where appropriate.
For mobile sources, such as the
proposed seismic survey, the User
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0.0
0.0
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14.5
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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).
For most cetacean species, densities
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100 in3 airgun
(SELcum)
(m)
752.8
Marine Mammal Occurrence
Frm 00020
100 in3 airgun
(Peak SPLflat)
(m)
61.5
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.
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7,800 in3
airgun array
(SELcum)
(m)
calculated by Bradford et al. (2017) from
summer–fall vessel-based surveys that
are part of the Hawaiian Island Cetacean
Ecosystem Assessment Survey
(HICEAS) were used. The surveys were
conducted by NMFS’ Southwest
Fisheries Science Center (SWFSC) and
Pacific Islands Fisheries Science Center
(PIFSC) in 2010 using two NOAA
research vessels, one during August 13–
December 1 and the other during
September 2–October 29. The densities
were estimated using a multiplecovariate line-transect approach
(Buckland et al. 2001; Marques and
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Buckland 2004). Density estimates for
pygmy and dwarf sperm whales and
spinner dolphins, which were not
calculated from the 2010 surveys, were
derived from the ‘‘Outer EEZ stratum’’
of the vessel-based HICEAS survey
conducted in summer–fall 2002 by
SWFSC (Barlow 2006) using linetransect methodology (Buckland et al.
2001). The density estimate for the false
killer whale was based on the pelagic
stock density calculated by Bradford et
al. (2015) using line-transect
methodology (Buckland et al. 2001).
All densities were corrected for
trackline detection probability bias (f(0))
and availability (g(0)) bias by the
authors. Bradford et al. (2017) used g(0)
values estimated by Barlow (2015),
whose analysis indicated that g(0) had
previously been overestimated,
particularly for high sea states. Barlow
(2006) used earlier estimates of g(0), so
densities used here for pygmy and
dwarf sperm whales and spinner
dolphins likely are underestimates. The
density for the ‘‘Sei or Bryde’s whale’’
category identified by Bradford et al.
(2017) was allocated between sei and
Bryde’s whales according to their
proportionate densities. Density
estimates for humpback and minke
whales were not available.
There is some uncertainty related to
the estimated density data and the
assumptions used in their calculations,
as with all density data estimates.
However, the approach used is based on
the best available data.
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
B harassment or Level A harassment,
radial distances to predicted isopleths
corresponding to the Level A
harassment and Level B harassment
thresholds are calculated, as described
above. We then use those distances to
calculate the area(s) around the airgun
array predicted to be ensonified to
sound levels that exceed the Level A
and Level B harassment thresholds. The
total ensonified area for the survey is
then calculated, based on the areas
predicted to be ensonified around the
array and the trackline distance. The
marine mammals predicted to occur
within these respective areas, based on
estimated densities, are expected to be
incidentally taken by the proposed
survey.
To summarize, the estimated density
of each marine mammal species within
an area (animals/km2) is multiplied by
the daily ensonified areas (km2) that
correspond to the Level A and Level B
harassment thresholds for the species.
The product (rounded) is the number of
instances of take for each species within
one day. The number of instances of
take for each species within one day is
then multiplied by the number of survey
days (plus 25 percent contingency, as
described below). The result is an
estimate of the number of instances that
marine mammals are predicted to be
exposed to airgun sounds above the
Level B harassment threshold and the
Level A harassment threshold over the
duration of the proposed survey.
Estimated takes for all marine mammal
species are shown in Table 8.
The proposed survey would occur
both within the U.S. EEZ and outside
the U.S. EEZ. We propose to authorize
incidental take that is expected to occur
as a result of the proposed survey both
within and outside the U.S. EEZ.
TABLE 8—NUMBERS OF POTENTIAL INCIDENTAL TAKE OF MARINE MAMMALS PROPOSED FOR AUTHORIZATION
Estimated and
proposed
Level A takes
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Species
Humpback whale 1 ...............................................................
Minke whale 1 ......................................................................
Bryde’s whale .......................................................................
Sei whale .............................................................................
Fin whale ..............................................................................
Blue whale 1 .........................................................................
Sperm whale ........................................................................
Cuvier’s beaked whale .........................................................
Longman’s beaked whale ....................................................
Blainville’s beaked whale .....................................................
Rough-toothed dolphin .........................................................
Bottlenose dolphin ...............................................................
Pantropical spotted dolphin .................................................
Spinner dolphin 1 .................................................................
Striped dolphin .....................................................................
Fraser’s dolphin ...................................................................
Risso’s dolphin .....................................................................
Melon-headed whale ............................................................
Pygmy killer whale ...............................................................
False killer whale .................................................................
Killer whale 1 ........................................................................
Short-finned pilot whale .......................................................
Pygmy sperm whale ............................................................
Dwarf sperm whale ..............................................................
Estimated
Level B takes
0
0
2
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
Proposed
Level B takes
0
0
25
6
2
1
51
8
85
76
812
246
639
23
685
577
130
97
119
16
2
218
87
214
2
1
25
6
2
3
51
8
85
76
812
246
639
32
685
577
130
97
119
16
5
218
87
214
Total proposed
Level A and
Level B takes
Total
Proposed
Level A
and Level B
takes as a
percentage of
population
2
1
27
6
2
3
51
8
85
76
812
246
639
32
685
577
130
97
119
16
5
218
87
214
<0.1
n/a
3.4
3.4
3.4
3.7
1.5
<0.1
1.9
3.3
12.9
4.1
4.0
0.9
3.3
3.4
1.8
1.7
3.5
1.0
4.9
1.8
1.2
1.2
1 The proposed number of authorized takes (Level B harassment only) for these species has been increased from the calculated take to mean
group size. Sources for mean group sizes are as follows: blue whale (Bradford et al. 2017); minke whale (Jackson et al. 2008); humpback whale
(Mobley et al. 2001); spinner dolphin (Barlow 2006); killer whale (Bradford et al. 2017).
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Species With Take Estimates Less
Than Mean Group Size: Using the
approach described above to estimate
take, the take estimates for the blue
whale, killer whale, and spinner
dolphin (Table 8) were less than the
average group sizes estimated for these
species. However, information on the
social structures and life histories of
these species indicates it is common for
them to be encountered in groups. As
the results of take calculations support
the likelihood that UH’s survey would
be expected to encounter and to
incidentally take these species, and we
believe it is likely that these species
may be encountered in groups, it is
reasonable to conservatively assume
that one group of each of these species
will be taken during the proposed
survey. We therefore propose to
authorize the take of the average (mean)
group size for the blue whale, killer
whale, and spinner dolphin to account
for the possibility that UH’s survey
encounters a group of any of these
species (Table 8).
Species With No Available Density
Data: No density data were available for
humpback and minke whales. Both
species would typically be found further
north than the proposed survey area
during the time of year that the
proposed survey is planned to occur,
based on sightings data around the
Hawaiian Islands (Carretta et al. 2017).
However, based on input from subject
matter experts, we believe it is
reasonable to assume that both species
may be encountered by UH during the
proposed survey. Humpback whales
have typically not been observed in the
project area in the fall (Carretta et al.
2017). However, there are increasing
anecdotal reports of confirmed sightings
of humpback whales from early
September through October in areas
near the planned project area (pers.
comm. E. Lyman, NOAA Office of
National Marine Sanctuaries, to J.
Carduner, NMFS, June 20, 2017). Like
humpback whales, sightings data does
not indicate that minke whales would
typically be expected to be present in
the project area in the fall (Carretta et al.
2017). However, detections of minke
whales are common in passive acoustic
recordings from various locations
around the main Hawaiian Islands,
including during the fall (pers. comm. E.
Oleson, NOAA PIFSC, to J. Carduner,
NMFS, June 20, 2017). Additionally, as
minke whales in the North Pacific do
not have a visible blow, they can be
easily missed by visual observers,
suggesting a lack of sightings is likely
related to misidentification or low
detection capability in poor sighting
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conditions (Rankin et al. 2007). Though
no density data are available, we believe
it is reasonable to conservatively assume
that UH’s proposed survey may
encounter and incidentally take minke
and humpback whales. We therefore
propose to authorize the take of the
average (mean) group size (weighted by
effort and rounded up) for the
humpback and minke whale (Table 8).
It should be noted that the proposed
take numbers shown in Table 8 are
believed to be conservative for several
reasons. First, in the calculations of
estimated take, 25% has been added in
the form of operational survey days
(equivalent to adding 25% to the
proposed line km to be surveyed) 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. Additionally, marine
mammals would be expected to move
away from a sound source that
represents an aversive stimulus.
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 take
estimates shown in Table 8.
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
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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, and, in the case
of a military readiness activity,
personnel safety, practicality of
implementation, and impact on the
effectiveness of the military readiness
activity.
UH 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, UH has
proposed to implement the following
mitigation measures for marine
mammals:
(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) Ship strike avoidance measures.
Vessel-Based Visual Mitigation
Monitoring
PSO observations would take place
during all daytime airgun operations
and nighttime start ups (if applicable) of
the airguns. Airgun operations would be
suspended when marine mammals are
observed within, or about to enter,
designated Exclusion Zones (as
described below). PSOs would also
watch for marine mammals near the
seismic vessel for at least 30 minutes
prior to the planned start of airgun
operations. Observations would also be
made during daytime periods when the
Kairei is underway without seismic
operations, such as during transits, to
allow for comparison of sighting rates
and behavior with and without airgun
operations and between acquisition
periods.
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During seismic operations, four visual
PSOs would be based aboard the Kairei.
PSOs would be appointed by JAMSTEC
with NMFS approval. During the
majority of seismic operations, two
PSOs would monitor for marine
mammals around the seismic vessel.
Use of two simultaneous observers
would increase the effectiveness of
detecting marine mammals around the
source vessel. However, during meal
times, only one PSO may be on duty.
PSO(s) would be on duty in shifts of
duration no longer than 4 hours. Other
crew would also be instructed to assist
in detecting marine mammals and in
implementing mitigation requirements
(if practical). Before the start of the
seismic survey, the crew would be given
additional instruction in detecting
marine mammals and implementing
mitigation requirements. The Kairei is a
suitable platform for marine mammal
observations. When stationed on the
observation platform, the PSO would
have a good view around the entire
vessel. During daytime, the PSO(s)
would scan the area around the vessel
systematically with reticle binoculars
(e.g., 7×50 Fujinon), Big-eye binoculars
(25×150), and with the naked eye.
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 would be
provided to NMFS for approval. At least
two PSOs must have a minimum of 90
days at-sea experience working as PSOs
during a deep penetration seismic
survey, with no more than eighteen
months elapsed since the conclusion of
the at-sea experience. One
‘‘experienced’’ visual PSO would be
designated as the lead for the entire
protected species observation team. The
lead would coordinate duty schedules
and roles for the PSO team and serve as
primary point of contact for the vessel
operator. The lead PSO would 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, to the maximum extent
practicable
The PSOs must have successfully
completed relevant training, including
completion of all required coursework
and passing a written and/or oral
examination developed for the training
program, and must have successfully
attained a bachelor’s degree from an
accredited college or university with a
major in one of the natural sciences and
a minimum of 30 semester hours or
equivalent in the biological sciences and
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at least one undergraduate course in
math or statistics. The educational
requirements may be waived if the PSO
has acquired the relevant skills through
alternate training, including (1)
secondary education and/or experience
comparable to PSO duties; (2) previous
work experience conducting academic,
commercial, or government-sponsored
marine mammal surveys; or (3) previous
work experience as a PSO; the PSO
should demonstrate good standing and
consistently good performance of PSO
duties.
In summary, a typical daytime cruise
would have scheduled two observers
(visual) on duty from the observation
platform, and an acoustic observer on
the passive acoustic monitoring system.
Vessel-Based Passive Acoustic
Mitigation Monitoring
Passive acoustic monitoring (PAM)
would take place to complement the
visual monitoring program. Visual
monitoring typically is not effective
during periods of poor visibility or at
night, and even with good visibility, is
unable to detect marine mammals when
they are below the surface or beyond
visual range. Acoustic monitoring can
be used in addition to visual
observations to improve detection,
identification, and localization of
cetaceans. The acoustic monitoring
would serve to alert visual observers (if
on duty) when vocalizing cetaceans are
detected. It is only useful when marine
mammals vocalize, but it can be
effective either by day or by night and
does not depend on good visibility. It
would be monitored in real time so that
visual observers can be alerted when
marine mammals are detected
acoustically.
The PAM system consists of hardware
(i.e., hydrophones) and software. The
‘‘wet end’’ of the system consists of a
towed hydrophone array that is
connected to the vessel by a tow cable.
A deck cable would connect the tow
cable to the electronics unit on board
where the acoustic station, signal
conditioning, and processing system
would be located. The acoustic signals
received by the hydrophones are
amplified, digitized, and then processed
by the software.
One acoustic PSO (in addition to the
four visual PSOs) would be on board.
The towed hydrophones would be
monitored 24 hours per day (either by
the acoustic PSO or by a visual PSO
trained in the PAM system if the
acoustic PSO is on break) while at the
seismic survey area during airgun
operations, and during most periods
when the Kairei is underway while the
airguns are not operating. However,
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PAM may not be possible if damage
occurs to the array or back-up systems
during operations. One PSO would
monitor the acoustic detection system at
any one time, in shifts no longer than
six hours, by listening to the signals via
headphones and/or speakers and
watching the real-time spectrographic
display for frequency ranges produced
by cetaceans.
When a vocalization is detected,
while visual observations are in
progress, the acoustic PSO would
contact the visual PSOs immediately, to
alert them to the presence of marine
mammals (if they have not already been
detected visually), in order to facilitate
a power down or shut down, if required.
The information regarding the marine
mammal acoustic detection would be
entered into a database.
Exclusion Zone and Buffer Zone
An exclusion zone 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
exclusion zone with a 500 m radius for
the full 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, enters,
or appears on a course to enter this
zone, the acoustic source would be
powered down (see Power Down
Procedures below). In addition to the
500 m EZ for the full array, a 100 m
exclusion zone would be established for
the single 100 in3 airgun. With certain
exceptions (described below), if a
marine mammal appears within, enters,
or appears on a course to enter this zone
the acoustic source would be shut down
entirely (see Shutdown Procedures
below).
Potential radial distances to auditory
injury zones were calculated on the
basis of maximum peak pressure using
values provided by the applicant (Table
7). The 500 m radial distance of the
standard EZ is intended to be
precautionary in the sense that it would
be expected to contain sound exceeding
peak pressure injury criteria for all
cetacean hearing groups, while also
providing a consistent, reasonably
observable zone within which PSOs
would typically be able to conduct
effective observational effort. Although
significantly greater distances may be
observed from an elevated platform
under good conditions, we believe that
500 m is likely regularly attainable for
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PSOs using the naked eye during typical
conditions.
An appropriate EZ based on
cumulative sound exposure level
(SELcum) criteria would be dependent on
the animal’s applied hearing range and
how that overlaps with the frequencies
produced by the sound source of
interest (i.e., via marine mammal
auditory weighting functions) (NMFS,
2016), and may be larger in some cases
than the zones calculated on the basis
of the peak pressure thresholds (and
larger than 500 m) depending on the
species in question and the
characteristics of the specific airgun
array. In particular, the EZ radii would
be larger for low-frequency cetaceans,
because their most susceptible hearing
range overlaps the low frequencies
produced by airguns, but the zones
would remain very small for midfrequency cetaceans (i.e., including the
‘‘small delphinoids’’ described below),
whose range of best hearing largely does
not overlap with frequencies produced
by airguns.
Consideration of exclusion zone
distances is inherently an essentially
instantaneous proposition—a rule or set
of rules that requires mitigation action
upon detection of an animal. This
indicates that consideration of peak
pressure thresholds is most relevant, as
compared with cumulative sound
exposure level thresholds, as the latter
requires that an animal accumulate
some level of sound energy exposure
over some period of time (e.g., 24
hours). A PSO aboard a mobile source
will typically have no ability to monitor
an animal’s position relative to the
acoustic source over relevant time
periods for purposes of understanding
whether auditory injury is likely to
occur on the basis of cumulative sound
exposure and, therefore, whether action
should be taken to avoid such potential.
Therefore, definition of an exclusion
zone based on SELcum thresholds is of
questionable relevance given relative
motion of the source and receiver (i.e.,
the animal). Cumulative SEL thresholds
are likely more relevant for purposes of
modeling the potential for auditory
injury than they are for informing realtime mitigation. We recognize the
importance of the accumulation of
sound energy to an understanding of the
potential for auditory injury and that it
is likely that, at least for low-frequency
cetaceans, some potential auditory
injury is likely impossible to mitigate
and should be considered for
authorization.
In summary, our intent in prescribing
a standard exclusion zone distance is to
(1) encompass zones for most species
within which auditory injury could
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occur on the basis of instantaneous
exposure; (2) provide additional
protection from the potential for more
severe behavioral reactions (e.g., panic,
antipredator response) for marine
mammals at relatively close range to the
acoustic source; (3) provide consistency
for PSOs, who need to monitor and
implement the exclusion zone; and (4)
to define a distance within which
detection probabilities are reasonably
high for most species under typical
conditions.
Our use of 500 m as the EZ is a
reasonable combination of factors. This
zone would contain all potential
auditory injury for all cetaceans (highfrequency, mid-frequency and lowfrequency functional hearing groups) as
assessed against peak pressure
thresholds (NMFS, 2016) (Table 7),
would contain all potential auditory
injury for high-frequency and midfrequency cetaceans as assessed against
SELcum thresholds (NMFS, 2016) (Table
7), and has been proven to be
practicable through past
implementation in seismic surveys
conducted for the oil and gas industry
in the Gulf of Mexico (as regulated by
BOEM pursuant to the Outer
Continental Shelf Lands Act (OCSLA)
(43 U.S.C. 1331–1356)). In summary, a
practicable criterion such as this has the
advantage of simplicity while still
providing in most cases a zone larger
than relevant auditory injury zones,
given realistic movement of source and
receiver.
The PSOs would also establish and
monitor a 1,000-m buffer zone. During
use of the acoustic source, occurrence of
marine mammals within the buffer zone
(but outside the exclusion zone) would
be communicated to the operator to
prepare for the potential power down or
shutdown of the acoustic source. The
buffer zone is discussed further under
Ramp Up Procedures below.
Power Down Procedures
A power down involves decreasing
the number of airguns in use such that
the radius of the mitigation zone is
decreased to the extent that marine
mammals are no longer in, or about to
enter, the 500 m EZ. During a power
down, one 100-in3 airgun would be
operated. The continued operation of
one 100-in3 airgun is intended to alert
marine mammals to the presence of the
seismic vessel in the area, and to allow
them to leave the area of the seismic
vessel if they choose. In contrast, a
shutdown occurs when all airgun
activity is suspended (shutdown
procedures are discussed below). If a
marine mammal is detected outside the
500 m EZ but appears likely to enter the
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500 m EZ, the airguns would be
powered down before the animal is
within the 500 m EZ. Likewise, if a
mammal is already within the 500 m EZ
when first detected, the airguns would
be powered down immediately. During
a power down of the airgun array, the
100-in3 airgun would be operated.
Following a power down, 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 the
following conditions have been met:
• 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, or
• it has not been seen within the 500
m EZ for 30 min in the case of
mysticetes and large odontocetes,
including sperm, pygmy sperm, dwarf
sperm, and beaked whales.
This power down requirement would
be in place for all marine mammals,
with the exception of small delphinoids
under certain circumstances. 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 of interacting with the
vessel and/or airgun array (e.g., bow
riding). This exception to the power
down requirement would apply solely
to specific genera of small dolphins—
Steno, Tursiops, Stenella and
Lagenodelphis—and would only apply
if the animals were traveling, including
approaching the vessel. If, for example,
an animal or group of animals is
stationary for some reason (e.g., feeding)
and the source vessel approaches the
animals, the power down requirement
applies. An animal with sufficient
incentive to remain in an area rather
than avoid an otherwise aversive
stimulus could either incur auditory
injury or disruption of important
behavior. If there is uncertainty
regarding identification (i.e., whether
the observed animal(s) belongs to the
group described above) or whether the
animals are traveling, the power down
would be implemented.
We propose 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
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below, 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). Please see
‘‘Potential Effects of the Specified
Activity on Marine Mammals’’ above for
further discussion of sound metrics and
thresholds and marine mammal hearing.
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 Kairei 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 powerdown/shutdown requirement for large
delphinoids in that it simplifies
somewhat the total range of decisionmaking 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.
At any distance, power down of the
acoustic source would also be required
upon observation of a large whale (i.e.,
sperm whale or any baleen whale) with
a calf, or upon observation of an
aggregation of large whales of any
species (i.e., sperm whale or any baleen
whale) that does not appear to be
traveling (e.g., feeding, socializing, etc.).
These would be the only two potential
situations that would require power
down of the array for marine mammals
observed beyond the 500 m exclusion
zone.
Shut Down Procedures
The single 100-in3 operating airgun
would be shut down if a marine
mammal is seen within or approaching
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the 100 m EZ for the single 100-in3
airgun. Shutdown would be
implemented if (1) an animal enters the
100 m EZ of the single 100-in3 airgun
after a power down has been initiated,
or (2) an animal is initially seen within
the 100 m EZ of the single 100-in3
airgun when more than one airgun
(typically the full array) is operating.
Airgun activity would not resume until
the marine mammal has cleared the 500
m EZ. Criteria for judging that the
animal has cleared the EZ would be as
described above.
The shutdown requirement, like the
power down requirement, would be
waived for dolphins of the following
genera: Steno, Tursiops, Stenella and
Lagenodelphis. The shutdown waiver
only applies if the animals are traveling,
including approaching the vessel. If
animals are stationary and the source
vessel approaches the animals, the
shutdown requirement would apply. If
there is uncertainty regarding
identification (i.e., whether the observed
animal(s) belongs to the group described
above) or whether the animals are
traveling, the shutdown would be
implemented.
Ramp-Up Procedures
Ramp-up of an acoustic source is
intended to provide a gradual increase
in sound levels following a power down
or shutdown, enabling animals to move
away from the source if the signal is
sufficiently aversive prior to its reaching
full intensity. The ramp-up procedure
involves 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. Ramp-up would be required
after the array is powered down or shut
down for any reason.
Ramp-up would begin by activating a
single airgun of the smallest volume in
the array and would continue in stages
by doubling the number of active
elements at the commencement of each
stage, with each stage of approximately
the same duration. This approach to
ramp-up (increments of array elements)
is proposed because it is relatively
simple to implement for the operator
and is intended to ensure a perceptible
increase in sound output per increment
while employing increments that
produce similar degrees of increase at
each step.
If airguns have been powered down or
shut down due to PSO detection of a
marine mammal within or approaching
the 500 m EZ, ramp-up would not be
initiated until all marine mammals have
cleared the EZ, during the day or night.
Visual and acoustic PSOs would be
required to monitor during ramp-up. If
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a marine mammal were detected by
visual PSOs within or approaching the
500 m EZ during ramp-up, a power
down (or shut down if appropriate)
would be implemented as though the
full array were operational. Criteria for
clearing the EZ would be as described
above.
Thirty minutes of pre-clearance
observation are required prior to rampup for any power down or shutdown of
longer than 30 minutes (i.e., if the array
were shut down during transit from one
line to another). This 30 minute preclearance period may occur during any
vessel activity (i.e., transit). If a marine
mammal were observed within or
approaching the 500 m EZ during this
pre-clearance period, ramp-up would
not be initiated until all marine
mammals cleared the EZ. Criteria for
clearing the EZ would be as described
above. If the airgun array has been shut
down for reasons other than mitigation
(e.g., mechanical difficulty) for a period
of less than 30 minutes, it may be
activated again without ramp-up if PSOs
have maintained constant visual and
acoustic observation and no visual
detections of any marine mammal have
occurred within the buffer zone and no
acoustic detections have occurred.
Ramp-up would be planned to occur
during periods of good visibility when
possible. However, ramp-up would be
allowed at night and during poor
visibility if the 500 m EZ and 1,000 m
buffer zone have been monitored by
visual PSOs for 30 minutes prior to
ramp-up and if acoustic monitoring has
occurred for 30 minutes prior to rampup with no acoustic detections during
that period.
The operator would be required to
notify a designated PSO of the planned
start of ramp-up as agreed-upon with
the lead PSO; the notification time
should not be less than 60 minutes prior
to the planned ramp-up. A designated
PSO must be notified again immediately
prior to initiating ramp-up procedures
and the operator must receive
confirmation from the PSO to proceed.
The operator must provide information
to PSOs documenting that appropriate
procedures were followed. Following
deactivation of the array for reasons
other than mitigation, the operator
would be required to communicate the
near-term operational plan to the lead
PSO with justification for any planned
nighttime ramp-up.
Based on our evaluation of the
applicant’s proposed measures, NMFS
has preliminarily determined that the
proposed mitigation measures provide
the means effecting the least practicable
impact on the affected species or stocks
and their habitat, paying particular
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attention to rookeries, mating grounds,
and areas of similar significance.
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 proposed
action area. Effective reporting is critical
both to compliance as well as ensuring
that the most value is obtained from the
required monitoring.
Monitoring and reporting
requirements prescribed by NMFS
should contribute to improved
understanding of one or more of the
following:
• Occurrence of marine mammal
species or stocks in the area in which
take is anticipated (e.g., presence,
abundance, distribution, density).
• Nature, scope, or context of likely
marine mammal exposure to potential
stressors/impacts (individual or
cumulative, acute or chronic), through
better understanding of: (1) Action or
environment (e.g., source
characterization, propagation, ambient
noise); (2) affected species (e.g., life
history, dive patterns); (3) co-occurrence
of marine mammal species with the
action; or (4) biological or behavioral
context of exposure (e.g., age, calving or
feeding areas).
• Individual marine mammal
responses (behavioral or physiological)
to acoustic stressors (acute, chronic, or
cumulative), other stressors, or
cumulative impacts from multiple
stressors.
• How anticipated responses to
stressors impact either: (1) Long-term
fitness and survival of individual
marine mammals; or (2) populations,
species, or stocks.
• Effects on marine mammal habitat
(e.g., marine mammal prey species,
acoustic habitat, or other important
physical components of marine
mammal habitat).
• Mitigation and monitoring
effectiveness.
UH submitted a marine mammal
monitoring and reporting plan in
section XIII of their IHA application.
Monitoring that is designed specifically
to facilitate mitigation measures, such as
monitoring of the EZ to inform potential
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power downs or shutdowns of the
airgun array, are described above and
are not repeated here.
UH’s monitoring and reporting plan
includes the following measures:
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, four visual PSOs
would be based aboard the Kairei. PSOs
would be appointed by JAMSTEC with
NMFS approval. During the majority of
seismic operations, two PSOs would
monitor for marine mammals around
the seismic vessel. Use of two
simultaneous observers would increase
the effectiveness of detecting animals
around the source vessel. However,
during meal times, only one PSO may
be on duty. PSOs would be on duty in
shifts of duration no longer than 4
hours. Other crew would also be
instructed to assist in detecting marine
mammals and in implementing
mitigation requirements (if practical).
During daytime, PSOs would scan the
area around the vessel systematically
with reticle binoculars (e.g., 7×50
Fujinon), Big-eye binoculars (25×150),
and with the naked eye.
PSOs would record data to estimate
the numbers of marine mammals
exposed to various received sound
levels and to document apparent
disturbance reactions or lack thereof.
Data would be used to estimate numbers
of animals potentially ‘taken’ by
harassment (as defined in the MMPA).
They would also provide information
needed to order a power down or shut
down of the airguns when a marine
mammal or sea turtle is within or near
the EZ.
When a sighting is made, the
following information about the sighting
would be recorded:
1. Species, group size, age/size/sex
categories (if determinable), behavior
when first sighted and after initial
sighting, heading (if consistent), bearing
and distance from seismic vessel,
sighting cue, apparent reaction to the
airguns or vessel (e.g., none, avoidance,
approach, paralleling, etc.), and
behavioral pace.
2. Time, location, heading, speed,
activity of the vessel, sea state,
visibility, and sun glare.
All observations and power downs or
shutdowns would be recorded in a
standardized format. Data would be
entered into an electronic database. The
accuracy of the data entry would be
verified by computerized data validity
checks as the data are entered and by
subsequent manual checking of the
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database. These procedures would allow
initial summaries of data to be prepared
during and shortly after the field
program and would facilitate transfer of
the data to statistical, graphical, and
other programs for further processing
and archiving. The time, location,
heading, speed, activity of the vessel,
sea state, visibility, and sun glare would
also be recorded at the start and end of
each observation watch, and during a
watch whenever there is a change in one
or more of the variables.
Results from the vessel-based
observations would provide:
1. The basis for real-time mitigation
(airgun power down or shut down).
2. Information needed to estimate the
number of marine mammals potentially
taken by harassment, which must be
reported to NMFS.
3. Data on the occurrence,
distribution, and activities of marine
mammals and turtles in the area where
the seismic study is conducted.
4. Information to compare the
distance and distribution of marine
mammals and turtles relative to the
source vessel at times with and without
seismic activity.
5. Data on the behavior and
movement patterns of marine mammals
and turtles seen at times with and
without seismic activity.
Vessel-Based Passive Acoustic
Monitoring
PAM would take place to complement
the visual monitoring program as
described above. Please see the
Proposed Mitigation section above for a
description of the PAM system and the
acoustic PSO’s duties. The acoustic PSO
would record data collected via the
PAM system, including the following:
An acoustic encounter identification
number, whether it was linked with a
visual sighting, date, time when first
and last heard and whenever any
additional information was recorded,
position and water depth when first
detected, bearing if determinable,
species or species group (e.g.,
unidentified dolphin, sperm whale),
types and nature of sounds heard (e.g.,
clicks, continuous, sporadic, whistles,
creaks, burst pulses, strength of signal,
etc.), and any other notable information.
Acoustic detections would also be
recorded for further analysis.
Reporting
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,
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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.
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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., populationlevel 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 the species listed in Table
2, given that NMFS expects the
anticipated effects of the proposed
seismic survey to be similar in nature.
Where there are meaningful differences
between species or stocks, or groups of
species, in anticipated individual
responses to activities, impact of
expected take on the population due to
differences in population status, or
impacts on habitat, NMFS has identified
species-specific factors to inform the
analysis.
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NMFS does not anticipate that serious
injury or mortality would occur as a
result of UH’s proposed seismic 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 one marine mammal
species (Table 8). 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 and not total
deafness that would not be likely to
affect the fitness of any individuals,
because of the constant movement of
both the Kairei and of the marine
mammals in the project area, 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 Kairei’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 area; therefore,
marine mammals that may be
temporarily displaced during survey
activities are expected to be able to
resume foraging once they have moved
away from areas with disturbing levels
of underwater noise. Because of the
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temporary nature of the disturbance, the
availability of similar habitat and
resources in the surrounding area, and
the lack of important or unique marine
mammal habitat, the impacts to marine
mammals and the food sources that they
utilize are not expected to cause
significant or long-term consequences
for individual marine mammals or their
populations. In addition, there are no
mating or calving areas known to be
biologically important to marine
mammals within the proposed project
area.
The activity is expected to impact a
very small percentage of all marine
mammal stocks that would be affected
by UH’s proposed survey (less than 2
percent for all marine mammal stocks).
Additionally, the acoustic ‘‘footprint’’ of
the proposed survey would be very
small relative to the ranges of all 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 seismic array would be active
24 hours per day throughout the
duration of the proposed survey.
However, the very brief overall duration
of the proposed survey (5.5 days) would
further limit potential impacts that may
occur as a result of the proposed
activity.
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.
Of the marine mammal species under
our jurisdiction that are likely to occur
in the project area, the following species
are listed as endangered under the ESA:
Blue, fin, sei, and sperm whales. There
are currently insufficient data to
determine population trends for blue,
fin, sei, and sperm whales (Carretta et
al., 2016); however, we are proposing to
authorize very small numbers of takes
for these species (Table 8), 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 UH’s seismic survey
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are not listed as threatened or
endangered under the ESA. There is no
designated critical habitat for any ESAlisted marine mammals within the
project area; and of the non-listed
marine mammals for which we propose
to authorize take, none are considered
‘‘depleted’’ or ‘‘strategic’’ by NMFS
under the MMPA.
NMFS concludes that exposures to
marine mammal species and stocks due
to UH’s proposed seismic survey would
result in only short-term (temporary and
short in duration) effects to individuals
exposed. Animals may temporarily
avoid the immediate area, but are not
expected to permanently abandon the
area. Major shifts in habitat use,
distribution, or foraging success are not
expected. NMFS does not anticipate the
proposed take estimates to impact
annual rates of recruitment or survival.
In summary and as described above,
the following factors primarily support
our preliminary determination that the
impacts resulting from this activity are
not expected to adversely affect the
marine mammal species or stocks
through effects on annual rates of
recruitment or survival:
• No mortality is anticipated or
authorized;
• The anticipated impacts of the
proposed activity on marine mammals
would primarily be temporary
behavioral changes due to avoidance of
the area around the survey vessel. The
relatively short duration of the proposed
survey (5.5 days) would further limit the
potential impacts of any temporary
behavioral changes that would occur;
• PTS is only anticipated to occur for
one species and the number of instances
of PTS that may occur are expected to
be very small in number (Table 8).
Instances of PTS that are incurred in
marine mammals would be of a low
level, due to constant movement of the
vessel and of the marine mammals in
the area, and the nature of the survey
design (not concentrated in areas of high
marine mammal concentration);
• The availability of alternate areas of
similar habitat value for marine
mammals to temporarily vacate the
survey area during the proposed survey
to avoid exposure to sounds from the
activity;
• The proposed project area does not
contain areas of significance for mating
or calving;
• The potential adverse effects on fish
or invertebrate species that serve as prey
species for marine mammals from the
proposed survey would be temporary
and spatially limited;
• The proposed mitigation measures,
including visual and acoustic
monitoring, power-downs, and
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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. Table 8 provides 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 authorization to be
taken, for all species and stocks, would
be considered small relative to the
relevant stocks or populations
(approximately 13 percent for roughtoothed dolphin, and less than five
percent for all other species and stocks).
For the blue whale, killer whale,
humpback whale, minke whale and
spinner dolphin we propose to
authorize take resulting from a single
exposure of one group of each species
or stock, as appropriate (using best
available information on mean group
size for these species or stocks). We
believe that a single incident of take of
one group of any of these species
represents take of small numbers for
that species
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 or stocks.
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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 preliminarily
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 four species of marine
mammals which are listed under the
ESA: the sei, fin, blue and sperm whale.
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 UH for conducting a seismic
survey in the central Pacific Ocean in
September, 2017, 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 the University of Hawaii’s (UH) IHA
application and using an array aboard
the R/V Kairei with characteristics
specified in the application, in the
Central Pacific Ocean.
3. General Conditions
(a) A copy of this IHA must be in the
possession of UH, the vessel operator
and other relevant personnel, the lead
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protected species observer (PSO), and
any other relevant designees of UH
operating under the authority of this
IHA.
(b) The species authorized for taking
are listed in Table 8. The taking, by
Level A and Level B harassment only,
is limited to the species and numbers
listed in Table 8. Any taking exceeding
the authorized amounts listed in Table
8 is prohibited and may result in the
modification, suspension, or revocation
of this IHA.
(c) 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.
(d) During use of the airgun(s), if
marine mammal species other than
those listed in Table 8 are detected by
PSOs, the acoustic source must be shut
down to avoid unauthorized take.
(e) UH shall ensure that the vessel
operator and other relevant vessel
personnel are briefed on all
responsibilities, communication
procedures, marine mammal monitoring
protocol, operational procedures, and
IHA requirements prior to the start of
survey activity, and when relevant new
personnel join the survey operations.
4. Mitigation Requirements
The holder of this Authorization is
required to implement the following
mitigation measures:
(a) UH must use five dedicated,
trained, NMFS-approved Protected
Species Observers (PSOs), including
four visual PSOs and one acoustic PSO.
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.
(b) At least two PSOs must have a
minimum of 90 days at-sea experience
working as PSOs during a deep
penetration seismic survey, with no
more than eighteen months elapsed
since the conclusion of the at-sea
experience. At least one of these must
have relevant experience as a visual
PSO and at least one must have relevant
experience as an acoustic PSO. One
‘‘experienced’’ visual PSO 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. 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
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yet gained relevant experience, to the
maximum extent practicable.
(c) Visual Observation
(i) During survey operations (e.g., any
day on which use of the acoustic source
is planned to occur; whenever the
acoustic source is in the water, whether
activated or not), two 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)
with the limited exception of meal times
during which one PSO may be on duty.
(ii) Visual monitoring must begin not
less than 30 minutes prior to ramp-up,
including for nighttime ramp-ups of the
airgun array, and must continue until
one hour after use of the acoustic source
ceases or until 30 minutes past sunset.
(iii) Visual PSOs shall coordinate to
ensure 360° 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.
(iv) Visual PSOs shall communicate
all observations to the acoustic PSO,
including any determination by the PSO
regarding species identification,
distance, and bearing and the degree of
confidence in the determination.
(v) Visual 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 observation per
24 hour period.
(vi) During good conditions (e.g.,
daylight hours; Beaufort sea state 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.
(d) Acoustic Observation—The R/V
Kairei must use a towed passive
acoustic monitoring (PAM) system,
which must be monitored beginning at
least 30 minutes prior to ramp-up and
at all times during use of the acoustic
source.
(i) One acoustic PSO (in addition to
the four visual PSOs) must be on board
to operate and oversee PAM operations.
Either the acoustic PSO or a visual PSO
with training in the PAM system must
monitor the PAM system at all times
while airguns are operating, and when
possible during periods when the
airguns are not operating, in shifts
lasting no longer than six hours.
(ii) Acoustic PSOs shall communicate
all detections to visual PSOs, when
visual PSOs are on duty, including any
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determination by the PSO regarding
species identification, distance, and
bearing and the degree of confidence in
the determination.
(iii) Survey activity may continue for
brief periods of time if the PAM system
malfunctions or is damaged. Activity
may continue for 30 minutes without
PAM 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 under the
following conditions:
(A) Daylight hours and sea state is less
than or equal to Beaufort sea state 4;
(B) No marine mammals (excluding
small delphinids) detected solely by
PAM in the 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
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—
PSOs shall establish and monitor a 500
m exclusion zone (EZ) and 1,000 m
buffer zone. The zones shall be based
upon radial distance from any element
of the airgun array (rather than being
based on the center of the array or
around the vessel itself). During use of
the acoustic source, occurrence of
marine mammals outside the EZ but
within 1,000 m from any element of the
airgun array shall be communicated to
the operator to prepare for potential
further mitigation measures as described
below. During use of the acoustic
source, occurrence of marine mammals
within the EZ, or on a course to enter
the EZ, shall trigger further mitigation
measures as described below.
(i) Ramp-up—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.
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.
(ii) If the airgun array has been
powered down or shut down due to a
marine mammal detection, ramp-up
shall not occur until all marine
mammals have cleared the EZ. A marine
mammal is considered to have cleared
the EZ if:
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(A) It has been visually observed to
have left the EZ
(B) It has not been observed within
the EZ, for 15 minutes (in the case of
small odontocetes) or for 30 minutes (in
the case of mysticetes and large
odontocetes including sperm, pygmy
sperm, dwarf sperm, and beaked
whales).
(iii) Thirty minutes of pre-clearance
observation of the 500 m EZ and 1,000
m buffer zone are required prior to
ramp-up for any power down or
shutdown of longer than 30 minutes.
This pre-clearance period may occur
during any vessel activity. If any marine
mammal (including delphinids) is
observed within or approaching the 500
m EZ during the 30 minute preclearance period, ramp-up may not
begin until the animal(s) has been
observed exiting the buffer zone or until
an additional time period has elapsed
with no further sightings (i.e., 15
minutes for small odontocetes and 30
minutes for all other species).
(iv) During ramp-up, PSOs shall
monitor the 500 m EZ and 1,000 m
buffer zone. Ramp-up may not be
initiated if any marine mammal
(including delphinids) is observed
within or approaching the 500 m EZ. If
a marine mammal is observed within or
approaching the 500 m EZ during rampup, a power down or shutdown shall be
implemented as though the full array
were operational. Ramp-up may not
begin again until the animal(s) has been
observed exiting the 500 m EZ or until
an additional time period has elapsed
with no further sightings (i.e., 15
minutes for small odontocetes and 30
minutes for all other species).
(v) If the airgun array has been shut
down for reasons other than mitigation
(e.g., mechanical difficulty) for a period
of less than 30 minutes, it may be
activated again without ramp-up if PSOs
have maintained constant visual and
acoustic observation and no visual
detections of any marine mammal have
occurred within the buffer zone and no
acoustic detections have occurred.
(vi) Ramp-up shall only occur at night
and at times of poor visibility where
operational planning cannot reasonably
avoid such circumstances. Ramp-up
may occur at night and during poor
visibility if the 500 m EZ and 1,000 m
buffer zone have been continually
monitored by visual PSOs for 30
minutes prior to ramp-up with no
marine mammal detections and if
acoustic monitoring has occurred for 30
minutes prior to ramp-up with no
acoustic detections during that period.
(vii) The vessel operator must notify
a designated PSO of the planned start of
ramp-up as agreed-upon with the lead
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PSO; the notification time should not be
less than 60 minutes prior to the
planned ramp-up. A designated PSO
must be notified again immediately
prior to initiating ramp-up procedures
and the operator must receive
confirmation from the PSO to proceed.
(f) Power Down Requirements—UH
shall power-down the airgun array if a
PSO detects a marine mammal within,
approaching, or entering the 500 m EZ.
A power down involves a decrease in
the number of operational airguns.
During a power down, one 100-in 3
airgun shall be continuously operated.
(i) Any PSO on duty has the authority
to call for power down of the airgun
array (visual PSOs on duty should be in
agreement on the need for power down
before requiring such action). When
there is certainty regarding the need for
mitigation action on the basis of either
visual or acoustic detection alone, the
relevant PSO(s) must call for such
action immediately.
(ii) When both visual and acoustic
PSOs are on duty, all detections must be
immediately communicated to the
remainder of the on-duty PSO team for
potential verification of visual
observations by the acoustic PSO or of
acoustic detections by visual PSOs and
initiation of dialogue as necessary.
(iii) The operator must establish and
maintain clear lines of communication
directly between PSOs on duty and
crew controlling the airgun array to
ensure that power down commands are
conveyed swiftly while allowing PSOs
to maintain watch.
(iv) When power down is called for by
a PSO, the power down must occur and
any dispute resolved only following
power down.
(v) The power down requirement is
waived for dolphins of the following
genera: Steno, Tursiops, Stenella and
Lagenodelphis. The power down waiver
only applies if animals are traveling,
including approaching the vessel. If
animals are stationary and the vessel
approaches the animals, the power
down requirement applies. If there is
uncertainty regarding identification (i.e.,
whether the observed animal(s) belongs
to the group described above) or
whether the animals are traveling,
power down must be implemented.
(vi) Upon implementation of a power
down, the source may be reactivated
under the conditions described at
4(e)(vi). Where there is no relevant zone
(e.g., shutdown due to observation of a
calf), a 30-minute clearance period must
be observed following the last
observation of the animal(s).
(vii) Power down of the acoustic
source is required upon observation of
a whale (i.e., sperm whale or any baleen
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whale) with calf at any distance, with
‘‘calf’’ defined as an animal less than
two-thirds the body size of an adult
observed to be in close association with
an adult.
(viii) Power down of the acoustic
source is required upon observation of
an aggregation (i.e., six or more animals)
of large whales of any species (i.e.,
sperm whale or any baleen whale) that
does not appear to be traveling (e.g.,
feeding, socializing, etc.).
(ix) When only the acoustic PSO is on
duty and a detection is made, if there is
uncertainty regarding species
identification or distance to the
vocalizing animal(s), the airgun array
must be powered down as a precaution.
(g) Shutdown requirements—An
exclusion zone of 100 m for the single
100-in3 airgun shall be established and
monitored by PSOs. If a marine mammal
is observed within, entering, or
approaching the 100 m exclusion zone
for the single 100-in3 airgun, whether
during implementation of a power down
or during operation of the full airgun
array, all airguns including the 100-in3
airgun shall be shut down.
(i) Upon implementation of a
shutdown, the source may be
reactivated under the conditions
described at 4(e).
(ii) Measures described for power
downs under 4(f)(i–v) shall also apply
in the case of a shutdown.
(h) Vessel Strike Avoidance—Vessel
operator and crew must maintain a
vigilant watch for all marine mammals
and slow down or stop the vessel or
alter course, as appropriate, to avoid
striking any marine mammal. A visual
observer aboard the vessel must monitor
a vessel strike avoidance zone around
the vessel according to the parameters
stated below. Visual observers
monitoring the vessel strike avoidance
zone 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.
(i) The vessel must maintain a
minimum separation distance of 100 m
from large whales. The following
avoidance measures must be taken if a
large whale is within 100 m of the
vessel:
(A) The vessel must reduce speed and
shift the engine to neutral, and must not
engage the engines until the whale has
moved outside of the vessel’s path and
the minimum separation distance has
been established.
(B) If the vessel is stationary, the
vessel must not engage engines until the
whale(s) has moved out of the vessel’s
path and beyond 100 m.
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(ii) The vessel must maintain a
minimum separation distance of 50 m
from all other marine mammals, with an
exception made for animals described in
4(g)(v) that approach the vessel. If an
animal is encountered during transit,
the vessel shall attempt to remain
parallel to the animal’s course, avoiding
excessive speed or abrupt changes in
course.
(iii) Vessel speeds must be reduced to
10 knots or less when mother/calf pairs,
pods, or large assemblages of cetaceans
are observed near the vessel.
(i) Miscellaneous Protocols
(i) The airgun array must be
deactivated when not acquiring data or
preparing to acquire data, except as
necessary for testing. Unnecessary use
of the acoustic source shall be avoided.
Notified operational capacity (not
including redundant backup airguns)
must not be exceeded during the survey,
except where unavoidable for source
testing and calibration purposes. All
occasions where activated source
volume exceeds notified operational
capacity must be noticed to the PSO(s)
on duty and fully documented. The lead
PSO must be granted access to relevant
instrumentation documenting acoustic
source power and/or operational
volume.
(ii) Testing of the acoustic source
involving all elements requires normal
mitigation protocols (e.g., ramp-up).
Testing limited to individual source
elements or strings does not require
ramp-up but does require pre-clearance.
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 must provide bigeye
binoculars (e.g., 25×150; 2.7 view angle;
individual ocular focus; height control)
of appropriate quality (i.e., Fujinon or
equivalent) solely for PSO use. These
shall be pedestal-mounted on the deck
at the most appropriate vantage point
that provides for optimal sea surface
observation, PSO safety, and safe
operation of the vessel. The operator
must also provide a night-vision device
suited for the marine environment for
use during nighttime ramp-up preclearance, at the discretion of the PSOs.
At minimum, the device should feature
automatic brightness and gain control,
bright light protection, infrared
illumination, and optics suited for lowlight situations.
(b) PSOs must also be equipped with
reticle binoculars (e.g., 7×50) of
appropriate quality (i.e., Fujinon or
equivalent), GPS, digital single-lens
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19:14 Jul 21, 2017
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reflex camera of appropriate quality
(i.e., Canon or equivalent), compass, and
any other tools necessary to adequately
perform necessary tasks, including
accurate determination of distance and
bearing to observed marine mammals.
(c) PSO Qualifications
(i) PSOs must have successfully
completed relevant training, including
completion of all required coursework
and passing a written and/or oral
examination developed for the training
program.
(ii) PSOs must have successfully
attained a bachelor’s degree from an
accredited college or university with a
major in one of the natural sciences and
a minimum of 30 semester hours or
equivalent in the biological sciences and
at least one undergraduate course in
math or statistics. The educational
requirements may be waived if the PSO
has acquired the relevant skills through
alternate experience. Requests for such
a waiver must include written
justification. 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 marine mammal
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—PSOs must use
standardized data 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 to
resume survey. If required mitigation
was not implemented, PSOs should
submit a description of the
circumstances. We require that, at a
minimum, the following information be
reported:
(i) PSO names and affiliations
(ii) Dates of departures and returns to
port with port name
(iii) Dates and times (Greenwich Mean
Time) of survey effort and times
corresponding with PSO effort
(iv) Vessel location (latitude/
longitude) when survey effort begins
and ends; vessel location at beginning
and end of visual PSO duty shifts
(v) Vessel heading and speed at
beginning and end of visual PSO duty
shifts and upon any line change
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(vi) Environmental conditions while
on visual survey (at beginning and end
of PSO shift and whenever conditions
change significantly), including wind
speed and direction, Beaufort sea state,
Beaufort wind force, swell height,
weather conditions, cloud cover, sun
glare, and overall visibility to the
horizon
(vii) Factors that may be contributing
to impaired observations during each
PSO shift change or as needed as
environmental conditions change (e.g.,
vessel traffic, equipment malfunctions)
(viii) 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-ramp-up survey,
ramp-up, shutdown, testing, shooting,
ramp-up completion, end of operations,
streamers, etc.)
(ix) If a marine mammal is sighted,
the following information should 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); also
note 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, 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 the center point of the acoustic
source;
(P) Platform activity at time of
sighting (e.g., deploying, recovering,
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testing, shooting, data acquisition,
other)
(Q) Description of any actions
implemented in response to the sighting
(e.g., delays, shutdown, ramp-up, speed
or course alteration, etc.); time and
location of the action should also be
recorded
(x) 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) 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, etc.)
(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),
and any other notable information.
6. Reporting
(a) UH shall submit a draft
comprehensive report 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
marine mammals 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 marine
mammal sightings (dates, times,
locations, activities, associated survey
activities). Geospatial data regarding
locations where the acoustic source was
used must be provided as an ESRI
shapefile with all necessary files and
appropriate metadata. In addition to the
report, all raw observational data shall
be made available to NMFS. The report
must summarize the data collected as
required under condition 5(d) of this
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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 to 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 from NMFS
on the draft report.
(b) Reporting injured or dead marine
mammals:
(i) In the event that the specified
activity clearly causes the take of a
marine mammal in a manner not
prohibited by this IHA (if issued), such
as serious injury or mortality, UH shall
immediately cease the specified
activities and immediately report the
incident to NMFS. 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 UH to determine
what measures are necessary to
minimize the likelihood of further
prohibited take and ensure MMPA
compliance. UH may not resume their
activities until notified by NMFS.
(ii) In the event that UH discovers an
injured or dead marine mammal, and
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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), UH shall immediately
report the incident to NMFS. 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 UH to
determine whether additional
mitigation measures or modifications to
the activities are appropriate.
(iii) In the event that UH 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),
UH shall report the incident to NMFS
within 24 hours of the discovery. UH
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 draft authorization, and any other
aspect of this Notice of Proposed IHA
for the proposed seismic survey by UH.
Please include with your comments any
supporting data or literature citations to
help inform our final decision on the
request for MMPA authorization.
Dated: July 19, 2017.
Catherine Marzin,
Acting Deputy Director, Office of Protected
Resources, National Marine Fisheries Service.
[FR Doc. 2017–15455 Filed 7–21–17; 8:45 am]
BILLING CODE 3510–22–P
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[Federal Register Volume 82, Number 140 (Monday, July 24, 2017)]
[Notices]
[Pages 34352-34382]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2017-15455]
[[Page 34351]]
Vol. 82
Monday,
No. 140
July 24, 2017
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 Geophysical Survey in the Central
Pacific Ocean; Notices
Federal Register / Vol. 82 , No. 140 / Monday, July 24, 2017 /
Notices
[[Page 34352]]
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DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
RIN 0648-XF330
Takes of Marine Mammals Incidental To Specified Activities;
Taking Marine Mammals Incidental to a Geophysical Survey in the Central
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 University of Hawaii (UH)
for authorization to take marine mammals incidental to a marine
geophysical survey in the Central 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 August
23, 2017.
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 ITP.Carduner@noaa.gov.
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 www.nmfs.noaa.gov/pr/permits/incidental/research.htm 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: Jordan Carduner, 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: www.nmfs.noaa.gov/pr/permits/incidental/research.htm. 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 is preparing an
Environmental Assessment (EA) to consider the environmental impacts
associated with the issuance of the proposed IHA. NMFS' EA is available
at www.nmfs.noaa.gov/pr/permits/incidental/research.htm. 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 15, 2016, NMFS received a request from the UH for an IHA
to take marine mammals incidental to conducting a marine geophysical
survey in the Central Pacific Ocean. On May 16, 2017, we deemed UH's
application for authorization to be adequate and complete. UH's request
is for take of a small number of 24 species of marine mammals by Level
B harassment and Level A harassment. Neither UH nor NMFS expects
mortality to result from this activity, 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
UH, in collaboration with the Japan Agency for Marine-Earth Science
and Technology (JAMSTEC), proposes to conduct a marine seismic survey
north of Hawaii in the Central Pacific Ocean over the course of five
and a half days in September 2017. The proposed survey would occur
north of the Hawaiian Islands, in the approximate area 22.6-25.0[deg]
N. and 153.5-157.4[deg] W. (See Figure 1 in IHA application). The
project area is partly within the exclusive economic zone (EEZ) of the
United States and partly in adjacent international waters. Water depths
in the area range from 4000 to 5000 m. The survey would involve one
source vessel, the Japan-flagged R/V (research vessel) Kairei. The
Kairei would deploy a 32-airgun array with a total volume of ~7800
cubic inches (in\3\) as an energy source.
[[Page 34353]]
Dates and Duration
The seismic survey would be carried out for approximately five and
a half days, including three and half days within the Hawaiian Islands
EEZ and two days in international waters. The survey would start on
approximately September 15, 2017. Exact dates of the activities are not
known as they are dependent on logistics and weather conditions.
Seismic activities would occur 24 hours per day during the proposed
survey.
Specific Geographic Region
The survey would encompass the approximate area 22.6-25.0[deg] N.
and 153.5-157.4[deg] W. in the central Pacific Ocean north of Hawaii,
partly within the Hawaiian Islands EEZ and partly in international
waters. Water depth in the survey area ranges from approximately 4000
to 5000 m. Representative survey track lines are shown in Figure 1 in
the IHA application. However, some deviation in actual track lines
could be necessary for reasons such as poor data quality, inclement
weather, or mechanical issues with the research vessel and/or
equipment. The Kairei would likely depart from Honolulu, Hawaii and
return to Honolulu.
Detailed Description of Specific Activity
Conventional seismic methodology would be used to image a typical/
stable oceanic crust, mantle, and the boundary between the Earth's
crust and the mantle (called the Mohorovi[ccaron]i[cacute]
discontinuity (Moho)). The data obtained from the survey would be used
to help better inform and further refine planning efforts for a
proposed ``Project Mohole'' under consideration for scheduling by the
International Ocean Discovery Program (IODP). The total survey effort
would consist of ~1083 kilometers (km) of transect lines (Figure 1 in
IHA application).
The R/V Kairei has a length of 106.0 meters (m), a beam of 16.0 m,
and a maximum draft of 4.7 m. Its propulsion system consists of two
diesel engines, each producing 2206 kW, which drive the two propellers
at 600 revolutions per minute (rpm). The operation speed during seismic
acquisition would be ~8.3 km/hour (~4.5 knots (kn)). When not towing
seismic survey gear, the Kairei typically cruises at 30 km/hour (~16.2
kn) and has a range of ~18,000 km.
During the survey, the Kairei would deploy an airgun array (i.e., a
certain number of airguns of varying sizes in a certain arrangement) as
an energy source (Table 1). An airgun is a device used to emit acoustic
energy pulses into the seafloor and generally consists of a steel
cylinder that is charged with high-pressure air. Release of the
compressed air into the water column generates a signal that reflects
(or refracts) off the seafloor and/or subsurface layers having acoustic
impedance contrast. When fired, a brief (~0.1 second) pulse of sound is
emitted by all airguns nearly simultaneously. The airguns are silent
during the intervening periods with the array typically fired on a
fixed distance (or shot point) interval. The return signal is recorded
by a listening device and later analyzed with computer interpretation
and mapping systems used to depict the subsurface.
The airgun array to be used would consist of 32 Bolt Annular Port
airguns, with a total volume of ~7800 in\3\. The airguns would be
configured as four identical linear arrays or ``strings'' (See Figure 2
in the IHA application for a visual representation of the strings).
Each string would have 8 airguns; the first and last airguns in the
strings would be spaced 10 m apart. All 8 airguns in each string would
be fired simultaneously. The 4 airgun strings would be towed behind the
Kairei and would be distributed across an area ~40 m x 10 m. The shot
interval would be ~22 seconds. The firing pressure of the array would
be ~2000 psi. During firing, a brief (~0.1 s) pulse of sound would be
emitted. The airguns would be silent during the intervening periods.
The array would be towed at a depth of 10 m. It is expected that the
aigun array would be active 24 hours per day during seismic activities.
Specifications of the Kairei's airgun array are shown in Table 1.
Source levels of the Kairei's airgun array are shown in Table 6.
Table 1--Specifications of the R/V Kairei Airgun Array
------------------------------------------------------------------------
------------------------------------------------------------------------
Number of airguns......................... 32.
Tow depth of energy source................ 10 meters (m).
Dominant frequency components............. 2-120 Hz.
Total volume.............................. ~7800 in.\3\
Pulse duration............................ ~0.1 second.
Shot interval............................. ~22 seconds.
------------------------------------------------------------------------
The receiving system would consist of one 6 km long hydrophone
streamer and ocean bottom seismometers (OBSs). As the airgun array is
towed along the survey lines, the hydrophone streamer would receive the
returning acoustic signals and transfer the data to the on-board
processing system. The OBSs would record the returning acoustic signals
internally for later analysis. Upon arrival at the survey area, two
OBSs would be deployed. The streamer and airgun array would then be
deployed, and seismic operations would commence. After completion of
seismic operations, the OBSs would be recovered by UH via a separate
vessel; the recovery cruise would be funded by the National Science
Foundation.
Survey protocols generally involve a predetermined set of survey,
or track, lines. The seismic acquisition vessel (source vessel) travels
down a linear track for some distance until a line of data is acquired,
then turn and acquire data on a different track. In the case of the
proposed survey, the two shorter north-south lines would each be
surveyed once, while the longer west-east line would be surveyed twice
(see Figure 1 in the IHA application).
In addition to the operations of the airgun array, a SeaBeam 3012
multibeam echosounder (MBES) would also be operated from the Kairei
continuously throughout the survey. The MBES would operate at 12
kilohertz (kHz) and would be hull-mounted on the Kairei. The
transmitting beamwidth of the MBES would be 2[deg] fore-aft and
150[deg] (max.) athwartship, or 120[deg] (in water up to 4500 m deep),
and 100[deg] (in water up to 8000 m).
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 Specified Activities
Section 4 of the application summarizes available information
regarding status and trends, distribution and habitat preferences, and
behavior and life history, of the potentially affected species.
Additional information regarding population trends and threats may be
found in NMFS' Stock Assessment Reports (SAR; www.nmfs.noaa.gov/pr/sars/), and more general information about these species (e.g.,
physical and behavioral descriptions) may be found on NMFS' Web site
(www.nmfs.noaa.gov/pr/species/mammals/).
Table 2 lists all species with expected potential for occurrence in
the central Pacific Ocean and summarizes information related to the
population or stock, including regulatory status under the MMPA and ESA
and potential biological removal (PBR), where known. For taxonomy, we
follow Committee on Taxonomy (2016). PBR is defined by the MMPA as the
maximum number of animals, not including natural mortalities, that may
be removed from a marine mammal stock while allowing that stock to
reach or maintain its optimum sustainable population (as
[[Page 34354]]
described in NMFS' SARs). While no mortality is anticipated or
authorized here, PBR and annual serious injury and mortality from
anthropogenic sources are included here as gross indicators of the
status of the species and other threats.
Marine mammal abundance estimates presented in this document
represent the total number of individuals that make up a given stock or
the total number estimated within a particular study or survey area.
NMFS' stock abundance estimates for most species represent the total
estimate of individuals within the geographic area, if known, that
comprises that stock. For some species, this geographic area may extend
beyond U.S. waters. All managed stocks in this region are assessed in
NMFS' U.S. Pacific SARs (e.g., Carretta et al. 2017). All values
presented in Table 2 are the most recent available at the time of
publication and are available in the 2016 SARs (Carretta et al. 2017),
available online at: www.nmfs.noaa.gov/pr/sars, except where noted
otherwise.
Table 2--Marine Mammals that Could Occur in the Project Area
--------------------------------------------------------------------------------------------------------------------------------------------------------
Stock abundance \2\
ESA/MMPA status; (CV, Nmin, most Relative occurrence
Species Stock strategic (Y/N) \1\ recent abundance PBR \4\ in project area
survey) \3\
--------------------------------------------------------------------------------------------------------------------------------------------------------
Order Cetartiodactyla--Cetacea--Superfamily Mysticeti (baleen whales)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Family: Balaenopteridae
--------------------------------------------------------------------------------------------------------------------------------------------------------
Humpback whale (Megaptera Central North Pacific. -/-; N................ 10,103 (0.300; 7,890; 83................... Seasonal; throughout
novaeangliae) \5\. 2006). known breeding
grounds during
winter and spring
(most common
November through
April).
Blue whale (Balaenoptera musculus). Central North Pacific. E/D; Y................ 81 (1.14; 38; 2010).. 0.1.................. Seasonal; infrequent
winter migrant; few
sightings, mainly
fall and winter;
considered rare.
Fin whale (Balaenoptera physalus).. Hawaii................ E/D; Y................ 58 (1.12; 27; 2010).. 0.1.................. Seasonal, mainly fall
and winter;
considered rare.
Sei whale (Balaenoptera borealis).. Hawaii................ E/D; Y................ 178 (0.90; 93; 2010). 0.2.................. Rare; limited
sightings of
seasonal migrants
that feed at higher
latitudes.
Bryde's whale (Balaenoptera brydei/ Hawaii................ -/-; N................ 798 (0.28; 633; 2010) 6.3.................. Uncommon; distributed
edeni). throughout the
Hawaiian Exclusive
Economic Zone.
Minke Whale (Balaenoptera Hawaii................ -/-; N................ n/a (n/a; n/a; 2010). Undet................ Seasonal, mainly fall
acutorostrata). and winter;
considered rare.
--------------------------------------------------------------------------------------------------------------------------------------------------------
Order Cetartiodactyla--Cetacea--Superfamily Odontoceti (toothed whales, dolphins, and porpoises)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Family: Physeteridae
--------------------------------------------------------------------------------------------------------------------------------------------------------
Sperm whale (Physeter Hawaii................ E/D; Y................ 3,354 (0.34; 2,539; 10.2................. Widely distributed
macrocephalus). 2010). year round.
Order Cetartiodactyla--Cetacea--Superfamily Odontoceti (toothed whales, dolphins, and porpoises)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Family: Kogiidae
--------------------------------------------------------------------------------------------------------------------------------------------------------
Pygmy sperm whale \6\ (Kogia Hawaii................ -/-; N................ 7,139 (2.91; n/a; Undet................ Widely distributed
breviceps). 2006). year round.
Dwarf sperm whale \6\ (Kogia sima). Hawaii................ -/-; N................ 17,519 (7.14; n/a; Undet................ Widely distributed
2006). year round.
--------------------------------------------------------------------------------------------------------------------------------------------------------
Order Cetartiodactyla--Cetacea--Superfamily Odontoceti (toothed whales, dolphins, and porpoises)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Family: Delphinidae
--------------------------------------------------------------------------------------------------------------------------------------------------------
Killer whale (Orcinus orca)........ Hawaii................ -/-; N................ 101 (1.00; 50; 2010). 1.................... Uncommon; infrequent
sightings.
False killer whale (Pseudorca Hawaii Pelagic........ -/-; N................ 1,540 (0.66; 928; 9.3.................. Regular.
crassidens). 2010).
Pygmy killer whale (Feresa Hawaii................ -/-; N................ 3,433 (0.52; 2,274; 23................... Year-round resident.
attenuata). 2010).
Short-finned pilot whale Hawaii................ -/-; N................ 12,422 (0.43; 8,872; 70................... Commonly observed
(Globicephala macrorhynchus). 2010). around Main Hawaiian
Islands and
Northwestern
Hawaiian Islands.
Melon headed whale (Peponocephala Hawaiian Islands...... -/-; N................ 5,794 (0.20; 4,904; 4.................... Regular.
electra). 2010).
Bottlenose dolphin (Tursiops Hawaii pelagic........ -/-; N................ 5,950 (0.59; 3,755; 38................... Common in deep
truncatus). 2010). offshore waters.
Pantropical spotted dolphin Hawaii pelagic........ -/-; N................ 15,917 (0.40; 11,508; 115.................. Common; primary
(Stenella attenuata). 2010). occurrence between
100 and 4,000 m
depth.
Striped dolphin (Stenella Hawaii................ -/-; N................ 20,650 (0.36; 15,391; 154.................. Occurs regularly year
coeruleoala). 2010). round but infrequent
sighting during
survey.
Spinner dolphin \6\ (Stenella Hawaii pelagic........ -/-; N................ 3,351 (0.74; n/a; Undet................ Common year-round in
longirostris). 2006). offshore waters.
Rough-toothed dolphin (Steno Hawaii................ -/-; N................ 6,288 (0.39; 4,581; 46................... Common throughout the
bredanensis). 2010). Main Hawaiian
Islands and Hawaiian
Islands EEZ.
Fraser's dolphin (Lagenodelphis Hawaii................ -/-; N................ 16,992 (0.66; 10,241; 102.................. Tropical species only
hosei). 2010). recently documented
within Hawaiian
Islands EEZ (2002
survey).
[[Page 34355]]
Risso's dolphin (Grampus griseus).. Hawaii................ -/-; N................ 7,256 (0.41; 5,207; 42................... Previously considered
2010). rare but multiple
sightings in
Hawaiian Islands EEZ
during various
surveys conducted
from 2002-2012.
--------------------------------------------------------------------------------------------------------------------------------------------------------
Order Cetartiodactyla--Cetacea--Superfamily Odontoceti (toothed whales, dolphins, and porpoises)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Family: Ziphiidae
--------------------------------------------------------------------------------------------------------------------------------------------------------
Cuvier's beaked whale (Ziphius Hawaii................ -/-; N................ 1,941 (n/a; 1,142; 11.4................. Year-round occurrence
cavirostris). 2010). but difficult to
detect due to diving
behavior.
Blainville's beaked whale Hawaii................ -/-; N................ 2,338 (1.13; 1,088; 11................... Year-round occurrence
(Mesoplodon densirostris). 2010). but difficult to
detect due to diving
behavior.
Longman's beaked whale (Indopacetus Hawaii................ -/-; N................ 4,571 (0.65; 2,773; 28................... Considered rare;
pacificus). 2010). however, multiple
sightings during
2010 survey.
--------------------------------------------------------------------------------------------------------------------------------------------------------
\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 (see footnote 3) 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\ Abundance estimates from Carretta et al. (2017) unless otherwise noted.
\3\ CV is coefficient of variation; Nmin is the minimum estimate of stock abundance. In some cases, CV is not applicable. For certain stocks, abundance
estimates are actual counts of animals and there is no associated CV. The most recent abundance survey that is reflected in the abundance estimate is
presented; there may be more recent surveys that have not yet been incorporated into the estimate.
\4\ 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 size (OSP).
\5\ Values for humpback whale are from the 2015 Alaska SAR (Muto et al. 2015).
\6\ Values for spinner dolphin, dwarf and pygmy sperm whale are from Barlow et al. (2006).
All species that could potentially occur in the proposed survey
area are included in Table 2. We have reviewed UH's species
descriptions, including life history information, distribution,
regional distribution, diving behavior, and acoustics and hearing, for
accuracy and completeness. We refer the reader to Section 4 of UH's IHA
application, rather than reprinting the information here. Below, for
the 24 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.
Humpback Whale
Humpback whales are found worldwide in all ocean basins. In winter,
most humpback whales occur in the subtropical and tropical waters of
the Northern and Southern Hemispheres (Muto et al., 2015). These
wintering grounds are used for mating, giving birth, and nursing new
calves. Humpback whales migrate nearly 3,000 mi (4,830 km) from their
winter breeding grounds to their summer foraging grounds in Alaska.
There are five stocks of humpback whales, one of which occurs in
Hawaii: The Central North Pacific Stock, which consists of winter/
spring populations in the Hawaiian Islands, which migrate primarily to
northern British Columbia/Southeast Alaska, the Gulf of Alaska, and the
Bering Sea/Aleutian Islands (Muto et al., 2015). Humpback whales occur
seasonally in Hawaii, with peak sightings between December and May each
year; however, sightings have occurred in other months in very low
numbers. Most humpback whales congregate off the island of Maui in the
shallow protected waters but can be seen off all of the islands
including the Northwestern Hawaiian Islands (Baird 2016).
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. The Hawaii DPS is the
only DPS that occurs in the survey area and is not listed under the ESA
(81 FR 62259; September 8, 2016). The Central North Pacific stock is
still considered a depleted and strategic stock under the MMPA.
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. 2008). 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.
2000). Blue whales belonging to the central Pacific stock appear to
feed in summer southwest of Kamchatka, south of the Aleutians, and in
the Gulf of Alaska (Stafford 2003; Watkins et al. 2000), and in winter
migrate to lower latitudes in the western and central Pacific,
including Hawaii (Stafford et al. 2001).
From ship line-transect surveys, Wade and Gerrodette (1993)
estimated 1,400 blue whales for the eastern tropical Pacific. A 2010
shipboard line-transect survey of the entire Hawaiian Islands EEZ
resulted in a summer/fall abundance estimate of 81 (CV = 1.14) blue
whales (Bradford et al. 2013). This is currently the best available
abundance estimate for this stock within the Hawaii EEZ, though the
majority of blue whales would be expected to be at higher latitudes
feeding grounds at this time of year. Blue whales are listed as
endangered under the ESA, and the Central North Pacific Stock of blue
whales is considered a depleted and strategic stock under the MMPA.
[[Page 34356]]
Fin Whale
Fin whales are found throughout all oceans from tropical to polar
latitudes. They have been considered rare in Hawaiian waters and are
absent to rare in eastern tropical Pacific waters (Hamilton 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).
During spring and summer, fin whale occurrence in Hawaii is
considered rare (DoN 2005). There were 5 sightings of fin whales during
summer-fall surveys in 2002, most to the northwest of the Main Hawaiian
Islands (Barlow et al. 2004) and two sightings in the Hawaiian Islands
EEZ during summer-fall 2010 (Bradford et al. 2013); there were no
sightings in or near the proposed survey area (Carretta et al. 2015).
Two additional sightings in the EEZ were made by observers on Hawaii-
based longline fishing vessels, including one near the proposed survey
area (Carretta et al. 2015). Fin whales are listed as endangered under
the ESA, and the Hawaii stock of fin whales is considered depleted
under the MMPA.
Sei Whale
The sei whale occurs in all ocean basins (Horwood 2009) but appears
to prefer mid-latitude temperate waters (Jefferson et al. 2008). 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).
Sei whales occur seasonally in Hawaii in the winter and spring
months and feed in higher latitude feeding grounds in the summer and
fall (Carretta et al., 2016). Sightings of this species are rare in
Hawaii. The species stays offshore of the islands in deeper waters
(Baird 2016). Sei whales are listed as endangered under the ESA, and
the Hawaii stock of sei whales is considered a depleted and strategic
stock under the MMPA.
Bryde's Whale
The 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). 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 (>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. 2008). 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 made during 2010 (Bradford et al. 2013). 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 or near the proposed
survey area (Barlow et al. 2004; Barlow 2006; Bradford et al. 2013;
Carretta et al. 2015). The Bryde's whale is not listed under the ESA,
and the Hawaii stock is not listed as depleted or strategic under the
MMPA.
Minke Whale
The minke whale has a cosmopolitan distribution ranging from the
tropics and subtropics to the ice edge in both hemispheres (Jefferson
et al. 2008) and is thought to occur seasonally in Hawaii, from
November through March (Rankin and Barlow 2005), though their migration
routes or destinations are unknown. While they are generally believed
to be uncommon in Hawaiian waters, several studies using acoustic
detections suggest that minke whales may be more common than previously
thought (Rankin et al. 2007; Oswald et al. 2011; Martin et al. 2012).
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 (Martin et al. 2012). Passive acoustic detections of minke
whales have been recorded at ALOHA station (22.75[deg] N., 158[deg] W.)
from October to 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). The minke
whale is not listed under the ESA, and the Hawaii stock is not listed
as depleted under the MMPA.
Sperm Whale
Sperm whales are widely distributed across the entire North Pacific
and into the southern Bering Sea in summer, but the majority are
thought to be south of 40[deg] N. in winter (Rice 1974, 1989; Gosho et
al. 1984; Miyashita et al. 1995). The Hawaii stock includes animals
found both within the Hawaiian Islands EEZ and in adjacent high seas
waters; however, because data on abundance, distribution, and human-
caused impacts are largely lacking for high seas waters, the status of
the Hawaii stock is evaluated based on data from U.S. EEZ waters of the
Hawaiian Islands (NMFS 2005).
Sperm whales are widely distributed in Hawaiian waters throughout
the year (Mobley et al. 2000). 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 adjacent to the proposed survey area (Barlow et al.
2004; Barlow 2006; Bradford et al. 2013). Sperm whales are listed as
endangered under the ESA, and the Hawaii stock is considered depleted
and strategic under the MMPA.
Pygmy Sperm Whale
Pygmy sperm whales are found in tropical and warm-temperate waters
throughout the world (Ross and Leatherwood 1994) and prefer deeper
waters with observations of this species in greater than 4,000 m depth
(Baird et al., 2013). Sightings are rare of this species. They 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). Both pygmy and
dwarf sperm whales 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. 2008). There is a single
stock of Pygmy sperm whales in Hawaii. Current abundance estimates for
this stock are unknown. Pygmy sperm whales are not listed as endangered
or threatened under the ESA, and the Hawaii stock is not considered
strategic or designated as depleted under the MMPA.
Dwarf Sperm Whale
Dwarf sperm whales are found throughout the world in tropical to
[[Page 34357]]
warm-temperate waters (Carretta et al., 2014). They are usually found
in waters deeper than 500 m, most often sighted in depths between 500
and 1,000 m, but they have been documented in depths as shallow as 106
m and as deep as 4,700 m (Baird 2016). This species is often alone or
in small groups of up to two to four individuals (Baird 2016). When
there are more than two animals together, they are often loosely
associated, with up to several hundred meters between pairs of
individuals (Baird 2016). There is one stock of dwarf sperm whales in
Hawaii. Sighting data suggests a small resident population off Hawaii
Island (Baird 2016). It has been suggested that this species is
probably one of the more abundant species of cetaceans in Hawaiian
waters (Baird 2016), though there are no current abundance estimates
for this stock. Dwarf sperm whales are not listed as endangered or
threatened under the ESA, and the Hawaii stock is not designated as
depleted or strategic under the MMPA.
Killer Whale
Killer whales have been observed in all oceans and seas of the
world (Leatherwood and Dahlheim 1978). Although reported from tropical
and offshore waters (Heyning and Dahlheim 1988), killer whales prefer
the colder waters of both hemispheres, with greatest abundances found
within 800 km of major continents (Mitchell 1975). High densities of
the species occur in high latitudes, especially in areas where prey is
abundant.
Killer whales are considered rare in Hawaiian waters (Carretta et
al. 2017). Twenty one sighting records were reported in Hawaiian waters
between 1994 and 2004 (Baird et al. 2006). 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. 2013),
none near the proposed survey area (Barlow et al. 2004; Bradford et al.
2013; Carretta et al. 2017). Numerous additional sightings in and north
of the EEZ have been made by observers on longliners, some in and near
the proposed survey area (Carretta et al. 2017). Killer whales are not
listed as endangered or threatened under the ESA (with the exception of
the endangered Southern Resident DPS which does not occur in the survey
area), and the Hawaii stock is not designated as depleted or strategic
under the MMPA.
False Killer Whale
False killer whales are found worldwide in tropical and warm-
temperate waters (Stacey et al. 1994). In the North Pacific, this
species is well known from southern Japan, Hawaii, and the eastern
tropical Pacific. The species 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).
Telemetry, photo-identification, and genetic studies have
identified three independent populations of false killer whales in
Hawaiian waters: Main (insular) Hawaiian Islands, Northwestern Hawaiian
Islands, and surrounding pelagic stock (Chivers et al. 2010; Baird et
al. 2010, 2013; Bradford et al. 2014). Based on the ranges of these
stocks, only the Hawaii pelagic stock is expected to occur in the
survey area (Carretta et al. 2017). False killer whales are not listed
as endangered or threatened under the ESA (with the exception of the
endangered Main Hawaiian Islands insular DPS which does not occur in
the survey area), and the Hawaii pelagic stock is not designated as
depleted or strategic under the MMPA.
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. 2008). In warmer water, it is
usually seen close to the coast (Wade and Gerrodette 1993), but it is
also found in deep waters. In Hawaiian waters, the pygmy killer whale
is found in nearshore waters but rarely offshore (Carretta et al.
2015). During small-boat surveys around the Hawaiian Islands in 2000-
2012, sightings were made in water up to 3,000 m deep (Baird et al.
2013).
Though a small resident population occurs in the main Hawaiian
Islands, pygmy killer whales are relatively rare in Hawaiian waters
(McSweeney et al. 2009). Satellite telemetry data from four tagged
pygmy killer whales suggest the resident group remains within 20 km of
shore (Baird et al. 2011) so would be unlikely in the proposed survey
area. Movements have been documented between Hawaii Island and Oahu and
between Oahu and Lanai (Baird et al. 2011a). Pygmy killer whales are
not listed under the ESA, and the Hawaii stock is not listed as is not
considered a depleted or strategic stock under the MMPA.
Short-Finned Pilot Whale
Short-finned pilot whales are found in all oceans, primarily in
tropical and warm-temperate waters (Carretta et al., 2016). The species
prefers deeper waters, ranging from 324 m to 4,400 m, with most
sightings between 500 m and 3,000 m (Baird 2016). This stock forms
stable social groups, with average group size of 18 individuals but may
form large aggregations of close to 200 individuals (Baird 2016). Other
research suggests a larger average group size of 40.9 individuals
(Bradford et al., 2017), but most of these sightings were farther
offshore in pelagic waters.
Short-finned pilot whales are commonly observed around the main
Hawaiian Islands and are also present around the Northwestern Hawaiian
Islands (Shallenberger 1981, Baird et al. 2013). Photo-identification
and telemetry studies suggest there may be inshore and pelagic
populations of short finned pilot whales in Hawaiian waters. Resighting
and social network analyses of individuals photographed off Hawaii
Island suggest the occurrence of one large and several smaller social
clusters that use those waters, with some individuals within the
smaller social clusters commonly resighted off Hawaii Island (Mahaffy
2012). Short-finned pilot whales are not listed as endangered or
threatened under the ESA, and the Hawaii stock is not considered a
depleted or strategic stock under the MMPA.
Melon-Headed Whale
Melon-headed whales are found in tropical and warm-temperate waters
throughout the world (Carretta et al., 2016). The distribution of
reported sightings suggests that the oceanic habitat of this species is
primarily equatorial waters (Perryman et al. 1994). The species forms
large groups, with average group size of almost 250 individuals, with
the largest group documented at close to 800 individuals (Baird 2016).
There are two demographically-independent populations in Hawaiian
waters, the Hawaiian Islands stock and the Kohala resident stock
(Carretta et al., 2016). The Kohala resident stock have a small range
restricted to the shallow waters around Hawaii Island, whereas the
Hawaiian Islands stock are found throughout the islands and offshore in
pelagic areas (Carretta et al., 2016). As such, only the Hawaiian
Islands stock may be affected by the proposed activities. This stock
prefers waters deeper than 1,000 m (Baird 2016). Satellite telemetry
data revealed distant pelagic movements, associated with feeding,
nearly to the edge of the Hawaiian Islands EEZ; the most distal
telemetry locations were near the proposed survey area at ~22.3[deg]
N., 154.0[deg] W. (Oleson et al. 2013). Melon-headed whales are not
listed as
[[Page 34358]]
endangered or threatened under the ESA and the Hawaiian Islands stock
is not considered a depleted or strategic stock under the MMPA.
Bottlenose Dolphin
Bottlenose dolphins are widely distributed throughout the world in
tropical and warm-temperate waters (Perrin et al. 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).
There are four resident insular stocks of bottlenose dolphins
around the Main Hawaiian Islands and one pelagic stock (Carretta et
al., 2016). Photo-identification studies have suggested that the 1,000-
m isobath serves as the boundary between resident insular stocks of the
Main Hawaiian Islands and the Hawaii pelagic stock (Martien et al.
2012). Only the pelagic stock may be affected by the proposed activity.
Bottlenose dolphins are not listed as endangered or threatened under
the ESA, and the Hawaii pelagic stock is not considered a depleted or
strategic stock under the MMPA.
Pantropical Spotted Dolphin
Pantropical spotted dolphins are primarily found in tropical and
subtropical waters worldwide (Perrin et al. 2009). There are two forms
of pantropical spotted dolphin: Coastal and offshore. Pantropical
spotted dolphins prefer deeper waters between 1,500 m and 3,000 m and
forms large groups with average group size of 60 individuals, with the
largest group estimated at 400 individuals (Baird 2016).
Pantropical spotted dolphins are common and abundant throughout the
Hawaiian archipelago (Baird et al. 2013). It is expected that it would
be one of the most abundant cetaceans in the proposed survey area.
There are four resident coastal stocks in Hawaii in addition to the
Hawaii pelagic stock. Due to their ranges, only the pelagic stock is
likely to be encountered in the project area (Carretta et al., 2016).
Pantropical spotted dolphins are not listed as endangered or threatened
under the ESA, and the Hawaii pelagic stock is not considered a
depleted or strategic stock under the MMPA.
Striped Dolphin
Striped dolphins are found in tropical to warm-temperate waters
throughout the world (Carretta et al., 2016). This is a deep water
species, preferring depths greater than 3,500 m (Baird 2016). Striped
dolphins occur primarily in pelagic waters, but have been observed
approaching shore where there is deep water close to the coast
(Jefferson et al. 2008). This species forms large groups, with an
average group size of 28 individuals, and a maximum group size of 100
individuals (Baird 2016).
The striped dolphin is expected to be one of the most abundant
cetaceans in the proposed survey area. It has been sighted near the
proposed survey area during summer-fall shipboard surveys of the Hawaii
Islands EEZ (Carretta et al. 2017). Striped dolphins are not listed as
endangered or threatened under the ESA, and the Hawaii stock of striped
dolphins is not considered a depleted or strategic stock under the
MMPA.
Spinner Dolphin
Spinner dolphins are found in tropical and warm-temperate waters
worldwide (Carretta et al., 2016). They are pantropical in
distribution, including oceanic tropical and sub-tropical waters
between 40[deg] N. and 40[deg] S. (Jefferson et al., 2008). Generally
considered a pelagic species (Perrin 2009b), spinner dolphins can also
be found in coastal waters and around oceanic islands (Rice 1998).
There are six separate stocks managed within the Hawaiian Islands EEZ
(Carretta et al. 2017); only individuals of the Hawaii pelagic stock
are expected to overlap with the proposed survey area. Spinner dolphins
have been sighted near the proposed survey area during summer-fall
surveys of the Hawaiian Islands EEZ (Carretta et al. 2017). The spinner
dolphin is not listed as endangered or threatened under the ESA, and
the Hawaii pelagic stock is not considered a depleted or strategic
stock under the MMPA.
Rough-Toothed Dolphin
Rough-toothed dolphins are found in tropical and warm-temperate
waters (Carretta et al., 2016). While there is evidence for two island-
associated stocks and one pelagic stock in Hawaii, there is only one
stock designated for Hawaii (Carretta et al., 2016). Most sightings of
this species off Kauai are in water depths of less than 1,000 m;
however, it is the most often sighted species in depths greater than
3,000 m (Baird 2016). This species forms stable associations as part of
larger groups, with average group sizes of 11 animals and maximum group
sizes, observed off Kauai, of 140 individuals (Baird 2016).
The rough-toothed dolphin is expected to be one of the most
abundant cetaceans in the proposed survey area (Barlow et al. 2004;
Barlow 2006; Bradford et al. 2013). During summer-fall surveys of the
Hawaiian Islands EEZ in 2002 and 2010, rough-toothed dolphins were
observed throughout the EEZ and near the proposed survey area. The
rough-toothed dolphin is not listed as endangered or threatened under
the ESA, and the Hawaii stock is not considered a depleted or strategic
stock under the MMPA.
Fraser's Dolphin
Fraser's dolphin are found in tropical waters (Carretta et al.,
2011). This is a deep water species occurring offshore of the Hawaiian
islands, with sightings occurring in water depths between 1,515 m and
4,600 m (Baird 2016). The species forms large groups with average group
sizes between 75 and 110 individuals (Baird 2016). Fraser's dolphin is
one of the most abundant cetaceans in the Hawaiian Islands EEZ (Barlow
2006; Bradford et al. 2013). Fraser's dolphin is not listed as
endangered or threatened under the ESA, and the Hawaii stock is not
considered a depleted or strategic stock under the MMPA.
Risso's Dolphin
Risso's dolphins are found in tropical to warm-temperate waters
(Carretta et al., 2016). The species occurs from coastal to deep water
but is most often found in depths greater than 3,000 m with the highest
sighting rate in depths greater than 4,500 m (Baird 2016). It occurs
between 60[deg] N. and 60[deg] S. where surface water temperatures are
at least 10[ordm] C (Kruse et al. 1999). The species forms small groups
with an average group size of 4 individuals, and a maximum group size
of 25 individuals off the coast of Hawaii (Baird 2016). Risso's
dolphins are not listed as endangered or threatened under the ESA, and
the Hawaii stock is not considered a depleted or strategic stock under
the MMPA.
Longman's Beaked Whale
The Longman's beaked whale, also known as Indo-Pacific beaked
whale, is considered one of the least known cetacean species (Carretta
et al., 2016). Longman's beaked whales are found in tropical waters
from the eastern Pacific westward through the Indian Ocean to the
eastern coast of Africa (Carretta et al., 2016). The species occurs 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 2009). Group sizes range from 18 to
110
[[Page 34359]]
individuals (Baird 2016). The Longman's beaked whale is not listed as
endangered or threatened under the ESA, and the Hawaii stock is not
considered a depleted or strategic stock under the MMPA.
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 found
in deep water over and near the continental slope (Jefferson et al.
2008). In the eastern tropical Pacific, the mean water depth for
sighted Cuvier's beaked whales was ~3.4 km (Ferguson et al. 2006).
During small-boat surveys around the Hawaiian Islands in 2000-2012,
sightings were made in water depths of 500-4000 m (Baird et al. 2013).
Summer/fall shipboard surveys of the waters within the U.S. EEZ of the
Hawaiian Islands resulted in 4 sightings in 2002 and 22 in 2010,
including markedly higher sighting rates during nearshore surveys in
the Northwestern Hawaiian Islands. (Barlow 2006, Bradford et al. 2013).
Resighting and movement data of individual Cuvier's beaked whales
suggest the existence of insular and offshore populations of this
species in Hawaiian waters. A 21-yr study off Hawaii Island suggests
long-term site fidelity and year-round occurrence (McSweeney et al.
2007). The Cuvier's beaked whale is not listed as endangered or
threatened under the ESA, and the Hawaii stock is not considered a
depleted or strategic stock under the MMPA.
Blainville's Beaked Whale
Blainville's beaked whale is found in tropical and warm temperate
waters of all oceans; it has the widest distribution throughout the
world of all mesoplodont species and appears to be common (Pitman
2009b). Recent analysis of Blainville's beaked whale resightings and
movements near the main Hawaiian Islands suggest the existence of
insular and pelagic populations of this species in Hawaiian waters
(McSweeney et al. 2007, Schorr et al. 2009, Baird et al. 2013). Photo-
identification of individual Blainville's beaked whales from Hawaii
Island since 1986 reveal repeated use of this area by individuals for
over 17 years (Baird et al. 2011) and 75% of individuals seen off
Hawaii Island link by association into a single social network (Baird
et al. 2013). Those individuals seen farthest from shore and in deep
water (>2100m) have not been resighted, suggesting they may be part of
an offshore, pelagic population (Baird et al. 2011). The Hawaii stock
of Blainville's beaked whales includes animals found both within the
Hawaiian Islands EEZ and in adjacent high seas waters. The Blainville's
beaked whale is not listed as endangered or threatened under the ESA,
and the Hawaii stock is not considered a depleted or strategic stock
under the MMPA.
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 hertz (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
(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
[[Page 34360]]
point (Richardson et al., 1995), and the sound level of a region is
defined by the total acoustical energy being generated by known and
unknown sources. These sources may include physical (e.g., wind and
waves, earthquakes, ice, atmospheric sound), biological (e.g., sounds
produced by marine mammals, fish, and invertebrates), and anthropogenic
(e.g., vessels, dredging, construction) sound. A number of sources
contribute to ambient sound, including the following (Richardson et
al., 1995):
Wind and waves: The complex interactions between wind and
water surface, including processes such as breaking waves and wave-
induced bubble oscillations and cavitation, are a main source of
naturally occurring ambient sound for frequencies between 200 Hz and 50
kHz (Mitson, 1995). In general, ambient sound levels tend to increase
with increasing wind speed and wave height. Surf sound becomes
important near shore, with measurements collected at a distance of 8.5
km from shore showing an increase of 10 dB in the 100 to 700 Hz band
during heavy surf conditions.
Precipitation: Sound from rain and hail impacting the
water surface can become an important component of total sound at
frequencies above 500 Hz, and possibly down to 100 Hz during quiet
times.
Biological: Marine mammals can contribute significantly to
ambient sound levels, as can some fish and snapping shrimp. The
frequency band for biological contributions is from approximately 12 Hz
to over 100 kHz.
Anthropogenic: Sources of ambient sound related to human
activity include transportation (surface vessels), dredging and
construction, oil and gas drilling and production, seismic surveys,
sonar, explosions, and ocean acoustic studies. Vessel noise typically
dominates the total ambient sound for frequencies between 20 and 300
Hz. In general, the frequencies of anthropogenic sounds are below 1 kHz
and, if higher frequency sound levels are created, they attenuate
rapidly. Sound from identifiable anthropogenic sources other than the
activity of interest (e.g., a passing vessel) is sometimes termed
background sound, as opposed to ambient sound.
The sum of the various natural and anthropogenic sound sources at
any given location and time--which comprise ``ambient'' or
``background'' sound--depends not only on the source levels (as
determined by current weather conditions and levels of biological and
human activity) but also on the ability of sound to propagate through
the environment. In turn, sound propagation is dependent on the
spatially and temporally varying properties of the water column and sea
floor, and is frequency-dependent. As a result of the dependence on a
large number of varying factors, ambient sound levels can be expected
to vary widely over both coarse and fine spatial and temporal scales.
Sound levels at a given frequency and location can vary by 10-20 dB
from day to day (Richardson et al., 1995). The result is that,
depending on the source type and its intensity, sound from a given
activity may be a negligible addition to the local environment or could
form a distinctive signal that may affect marine mammals. Details of
source types are described in the following text.
Sounds are often considered to fall into one of two general types:
Pulsed and non-pulsed (defined in the following). The distinction
between these two sound types is important because they have differing
potential to cause physical effects, particularly with regard to
hearing (e.g., Ward, 1997 in Southall et al., 2007). Please see
Southall et al. (2007) for an in-depth discussion of these concepts.
Pulsed sound sources (e.g., airguns, explosions, gunshots, sonic
booms, impact pile driving) produce signals that are brief (typically
considered to be less than one second), broadband, atonal transients
(ANSI, 1986, 2005; Harris, 1998; NIOSH, 1998; ISO, 2003) and occur
either as isolated events or repeated in some succession. Pulsed sounds
are all characterized by a relatively rapid rise from ambient pressure
to a maximal pressure value followed by a rapid decay period that may
include a period of diminishing, oscillating maximal and minimal
pressures, and generally have an increased capacity to induce physical
injury as compared with sounds that lack these features.
Non-pulsed sounds can be tonal, narrowband, or broadband, brief or
prolonged, and may be either continuous or non-continuous (ANSI, 1995;
NIOSH, 1998). Some of these non-pulsed sounds can be transient signals
of short duration but without the essential properties of pulses (e.g.,
rapid rise time). Examples of non-pulsed sounds include those produced
by vessels, aircraft, machinery operations such as drilling or
dredging, vibratory pile driving, and active sonar systems (such as
those used by the U.S. Navy). The duration of such sounds, as received
at a distance, can be greatly extended in a highly reverberant
environment.
Airgun arrays produce pulsed signals with energy in a frequency
range from about 10-2,000 Hz, with most energy radiated at frequencies
below 200 Hz. The amplitude of the acoustic wave emitted from the
source is equal in all directions (i.e., omnidirectional), but airgun
arrays do possess some 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 SeaBeam 3012 MBES would also be operated from
the Kairei continuously throughout the survey. Due to the lower source
level of the MBES relative to the Kairei's airgun array (241 dB re 1
[mu]Pa [middot] m for the MBES versus 259 dB re 1 [mu]Pa [middot] m
(rms) for the airgun array), the sounds from the MBES are expected to
be effectively subsumed by the sounds from the airgun array. In
addition, 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. For these
reasons, any marine mammal that was 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. As such, the MBES is
not expected to result in the take of any marine mammal that has not
already been taken by the sounds from the airgun array, and therefore
we do not consider noise from the MBES further in this analysis.
Acoustic Effects
Here, we first provide background information on marine mammal
hearing before discussing the potential effects of the use of active
acoustic sources on marine mammals.
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
[[Page 34361]]
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. Pinniped functional hearing is not discussed here, as
no pinnipeds are expected to be affected by the specified activity. The
functional groups and the associated frequencies are indicated below
(note that these frequency ranges correspond to the range for the
composite group, with the entire range not necessarily reflecting the
capabilities of every species within that group):
Low-frequency cetaceans (mysticetes): Generalized hearing
is estimated to occur between approximately 7 Hz and 35 kHz, with best
hearing estimated to be from 100 Hz to 8 kHz;
Mid-frequency cetaceans (larger toothed whales, beaked
whales, and most delphinids): Generalized hearing is estimated to occur
between approximately 150 Hz and 160 kHz, with best hearing from 10 to
less than 100 kHz;
High-frequency cetaceans (porpoises, river dolphins, and
members of the genera Kogia and Cephalorhynchus; including two members
of the genus Lagenorhynchus, on the basis of recent echolocation data
and genetic data): Generalized hearing is estimated to occur between
approximately 275 Hz and 160 kHz.
Table 3--Marine Functional Mammal Hearing Groups and Their Generalized
Hearing Ranges
------------------------------------------------------------------------
Hearing group Generalized hearing range *
------------------------------------------------------------------------
Low frequency (LF) cetaceans (baleen 7 Hz to 35 kHz.
whales).
Mid-frequency (MF) cetaceans (dolphins, 150 Hz to 160 kHz.
toothed whales, beaked whales, bottlenose
whales).
High-frequency (HF) cetaceans (true 275 Hz to 160 kHz.
porpoises, Kogia, river dolphins,
cephalorhynchid, Lagenorhynchus cruciger
and L. australis).
Phocid pinnipeds (PW) (underwater) (true 50 Hz to 86 kHz.
seals).
Otariid pinnipeds (OW) (underwater) (sea 60 Hz to 39 kHz.
lions and fur seals).
------------------------------------------------------------------------
* Represents the generalized hearing range for the entire group as a
composite (i.e., all species within the group), where individual
species' hearing ranges are typically not as broad. Generalized
hearing range chosen based on ~65 dB threshold from normalized
composite audiogram, with the exception for lower limits for LF
cetaceans (Southall et al., 2007) and PW pinniped (approximation).
For more detail concerning these groups and associated frequency
ranges, please see NMFS (2016) for a review of available information.
Twenty four marine mammal species (all cetaceans) have the reasonable
potential to co-occur with the proposed survey activities. Please refer
to Table 2. Of the cetacean species that may be present, six are
classified as low-frequency cetaceans (i.e., all mysticete species), 16
are classified as mid-frequency cetaceans (i.e., all delphinid and
ziphiid species and the sperm whale), and two are classified as high-
frequency cetaceans (i.e., Kogia spp.).
Potential Effects of 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. Note that, in the following discussion, we refer
in many cases to a recent review article concerning studies of noise-
induced hearing loss conducted from 1996-2015 (i.e., Finneran, 2015).
For study-specific citations, please see that work. 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 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
[[Page 34362]]
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.
1. 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 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).
2. 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
[[Page 34363]]
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).
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
[[Page 34364]]
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
significantly at onset of airgun use at sites with a median distance of
41-45 km from the survey. Blackwell et al. (2015) expanded this
analysis to show that whales actually increased calling rates as soon
as airgun signals were detectable before ultimately decreasing calling
rates at higher received levels (i.e., 10-minute SELcum of
~127 dB). Overall, these results suggest that bowhead whales may adjust
their vocal output in an effort to compensate for noise before ceasing
vocalization effort and ultimately deflecting from the acoustic source
(Blackwell et al., 2013, 2015). These studies demonstrate that even low
levels of noise received far from the source can induce changes in
vocalization and/or behavior for mysticetes.
Avoidance is the displacement of an individual from an area or
migration path as a result of the presence of a sound or other
stressors, and is one of the most obvious manifestations of disturbance
in marine mammals (Richardson et al., 1995). For example, gray whales
are known to change direction--deflecting from customary migratory
paths--in order to avoid noise from seismic surveys (Malme et al.,
1984). Humpback whales showed avoidance behavior in the presence of an
active seismic array during observational studies and controlled
exposure experiments in western Australia (McCauley et al., 2000).
Avoidance may be short-term, with animals returning to the area once
the noise has ceased (e.g., Bowles et al., 1994; Goold, 1996; Stone et
al., 2000; Morton and Symonds, 2002; Gailey et al., 2007). Longer-term
displacement is possible, however, which may lead to changes in
abundance or distribution patterns of the affected species in the
affected region if habituation to the presence of the sound does not
occur (e.g., Bejder et al., 2006; Teilmann et al., 2006).
A flight response is a dramatic change in normal movement to a
directed and rapid movement away from the perceived location of a sound
source. The flight response differs from other avoidance responses in
the intensity of the response (e.g., directed movement, rate of
travel). Relatively little information on flight responses of marine
mammals to anthropogenic signals exist, although observations of flight
responses to the presence of predators have occurred (Connor and
Heithaus, 1996). The result of a flight response could range from
brief, temporary exertion and displacement from the area where the
signal provokes flight to, in extreme cases, marine mammal strandings
(Evans and England, 2001). However, it should be noted that response to
a perceived predator does not necessarily invoke flight (Ford and
Reeves, 2008), and whether individuals are solitary or in groups may
influence the response.
Behavioral disturbance can also impact marine mammals in more
subtle ways. Increased vigilance may result in costs related to
diversion of focus and attention (i.e., when a response consists of
increased vigilance, it may come at the cost of decreased attention to
other critical behaviors such as foraging or resting). These effects
have generally not been demonstrated for marine mammals, but studies
involving fish and terrestrial animals have shown that increased
vigilance may substantially reduce feeding rates (e.g., Beauchamp and
Livoreil, 1997; Fritz et al., 2002; Purser and Radford, 2011). In
addition, chronic disturbance can cause population declines through
reduction of fitness (e.g., decline in body condition) and subsequent
reduction in reproductive success, survival, or both (e.g., Harrington
and Veitch, 1992; Daan et al., 1996; Bradshaw et al., 1998). However,
Ridgway et al. (2006) reported that increased vigilance in bottlenose
dolphins exposed to sound over a five-day period did not cause any
sleep deprivation or stress effects.
Many animals perform vital functions, such as feeding, resting,
traveling, and socializing, on a diel cycle (24-hour cycle). Disruption
of such functions resulting from reactions to stressors such as sound
exposure are more likely to be significant if they last more than one
diel cycle or recur on subsequent days (Southall et al., 2007).
Consequently, a behavioral response lasting less than one day and not
recurring on subsequent days is not considered particularly severe
unless it could directly affect reproduction or survival (Southall et
al., 2007). Note that there is a difference between multi-day
substantive behavioral reactions and multi-day anthropogenic
activities. For example, just because an activity lasts for multiple
days does not necessarily mean that individual animals are either
exposed to activity-related stressors for multiple days or, further,
exposed in a manner resulting in sustained multi-day substantive
behavioral responses.
Stone (2015) reported data from at-sea observations during 1,196
seismic surveys from 1994 to 2010. When large arrays of airguns
(considered to be 500 in\3\ or more) were firing, lateral displacement,
more localized avoidance, or other changes in behavior were evident for
most odontocetes. However, significant responses to large arrays were
found only for the minke whale and fin whale. Behavioral responses
observed included changes in swimming or surfacing behavior, with
indications that cetaceans remained near the water surface at these
times. Cetaceans were recorded as feeding less often when large arrays
were active. Behavioral observations of gray whales during a seismic
survey monitored whale movements and respirations pre-, during and
post-seismic survey
[[Page 34365]]
(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.
3. 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 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).
4. 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.
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
[[Page 34366]]
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 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 Kairei travels at a speed of ~8.3 km/hour while towing seismic
survey gear (LGL 2017). 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). Commercial fishing vessels were responsible for three
percent of recorded collisions, while no such incidents were reported
for geophysical survey vessels during that time period.
It is possible for ship strikes to occur while traveling at slow
speeds. For example, a hydrographic survey vessel traveling at low
speed (5.5 kn) while conducting mapping surveys off the central
California coast struck and killed a blue whale in 2009. The State of
California determined that the whale had suddenly and unexpectedly
surfaced beneath the hull, with the result that the propeller severed
the whale's vertebrae, and that this was an unavoidable event. This
strike represents the only such incident in approximately 540,000 hours
of similar coastal mapping activity (p = 1.9 x 10-6; 95% CI
= 0 -5.5 x 10-6; NMFS, 2013b). In addition, a research
vessel reported a fatal strike in 2011 of a dolphin in the Atlantic,
demonstrating that it is possible for strikes involving smaller
cetaceans to occur. In that case, the incident report indicated that an
animal apparently was struck by the vessel's propeller as it was
intentionally swimming near the vessel. While indicative of the type of
unusual events that cannot be ruled out, neither of these instances
represents a circumstance that would be considered reasonably
foreseeable or that would be considered preventable.
Although the likelihood of the vessel striking a marine mammal is
low, we require a robust ship strike avoidance protocol (see ``Proposed
Mitigation''), which we believe eliminates any foreseeable risk of ship
strike. We anticipate that vessel collisions involving a seismic data
acquisition vessel towing gear, while not impossible, represent
unlikely, unpredictable events for which there are no preventive
measures. Given the required mitigation measures, the relatively slow
speed of the vessel towing gear, the presence of bridge crew watching
for obstacles at all times (including marine mammals), the presence of
marine mammal observers, and the short duration of the survey (5.5
days), 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, although one stranding event was
associated with the use of seismic airguns. This event occurred in the
Gulf of California, coincident with seismic reflection profiling by the
R/V Maurice Ewing operated by Columbia University's Lamont-Doherty
Earth Observatory and involved two Cuvier's beaked whales (Hildebrand,
2004). The vessel had been firing an array of 20 airguns with a total
[[Page 34367]]
volume of 8,500 in\3\ (Hildebrand, 2004; Taylor et al., 2004). 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 survey to result in marine mammal stranding and have
concluded that, based on the best available information, stranding is
not expected to occur.
Other Potential Impacts--Here, we briefly address the potential
risks due to entanglement and contaminant spills. We are not aware of
any records of marine mammal entanglement in towed arrays such as those
considered here. The discharge of trash and debris is prohibited (33
CFR 151.51-77) unless it is passed through a machine that breaks up
solids such that they can pass through a 25-mm mesh screen. All other
trash and debris must be returned to shore for proper disposal with
municipal and solid waste. Some personal items may be accidentally lost
overboard. However, U.S. Coast Guard and Environmental Protection Act
regulations require operators to become proactive in avoiding
accidental loss of solid waste items by developing waste management
plans, posting informational placards, manifesting trash sent to shore,
and using special precautions such as covering outside trash bins to
prevent accidental loss of solid waste. There are no meaningful
entanglement risks posed by the described activity, and entanglement
risks are not discussed further in this document.
Marine mammals could be affected by accidentally spilled diesel
fuel from a vessel associated with proposed survey activities.
Quantities of diesel fuel on the sea surface may affect marine mammals
through various pathways: surface contact of the fuel with skin and
other mucous membranes, inhalation of concentrated petroleum vapors, or
ingestion of the fuel (direct ingestion or by the ingestion of oiled
prey) (e.g., Geraci and St. Aubin, 1980, 1985, 1990). However, the
likelihood of a fuel spill during any particular geophysical survey is
considered to be remote, and the potential for impacts to marine
mammals would depend greatly on the size and location of a spill and
meteorological conditions at the time of the spill. Spilled fuel would
rapidly spread to a layer of varying thickness and break up into narrow
bands or windrows parallel to the wind direction. The rate at which the
fuel spreads would be determined by the prevailing conditions such as
temperature, water currents, tidal streams, and wind speeds. Lighter,
volatile components of the fuel would evaporate to the atmosphere
almost completely in a few days. Evaporation rate may increase as the
fuel spreads because of the increased surface area of the slick.
Rougher seas, high wind speeds, and high temperatures also tend to
increase the rate of evaporation and the proportion of fuel lost by
this process (Scholz et al., 1999). We do not anticipate potentially
meaningful effects to marine mammals as a result of any contaminant
spill resulting from the proposed survey activities, and contaminant
spills are not discussed further in this document.
Anticipated Effects on Marine Mammal Habitat
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 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 survey would occur over a relatively short time
period (5.5 days) and would occur over a very small area relative to
the area available as marine mammal habitat in the central Pacific
Ocean. We do not have any information to suggest the proposed survey
area represents a significant feeding area for any marine mammal, and
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
[[Page 34368]]
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 the seismic airguns have the potential to result in disruption of
behavioral patterns for individual marine mammals. There is also some
potential for auditory injury (Level A harassment) to result, primarily
for mysticetes and high frequency cetaceans (i.e., kogiidae spp.), due
to larger predicted auditory injury zones for those functional hearing
groups. Auditory injury is unlikely to occur for mid-frequency species
given very small modeled zones of injury for those species. The
proposed mitigation and monitoring measures are expected to minimize
the severity of such taking to the extent practicable.
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 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., 2011). 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 120 dB re 1 [mu]Pa (rms) for continuous (e.g.,
vibratory pile-driving, drilling) and above 160 dB re 1 [mu]Pa (rms)
for non-explosive impulsive (e.g., seismic airguns) or intermittent
(e.g., scientific sonar) sources. UH'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 4 below. The references, analysis, and methodology
used in the development of the thresholds are described in NMFS 2016
Technical Guidance, which may be accessed at: https://www.nmfs.noaa.gov/pr/acoustics/guidelines.htm. As described above, UH's proposed activity
includes the use of intermittent and impulsive seismic sources.
[[Page 34369]]
Table 4--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
------------------------------------------------------------------------
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
acoustic thresholds.
The proposed survey would entail use of a 32-airgun array with a
total discharge of 7,800 in\3\ at a tow depth of 10 m. The distance to
the predicted isopleth corresponding to the threshold for Level B
harassment (160 dB re 1 [mu]Pa) was calculated based on results of
modeling performed by Lamont-Doherty Earth Observatory (LDEO) of
Columbia University. Received sound levels were predicted by LDEO's
model (Diebold et al. 2010) as a function of distance from the full 32-
airgun array as well as for a single 100 in\3\ airgun, which would be
used during power-downs. The LDEO modeling approach uses ray tracing
for the direct wave traveling from the array to the receiver and its
associated source ghost (reflection at the air-water interface in the
vicinity of the array), in a constant-velocity half-space (infinite
homogeneous ocean layer unbounded by a seafloor). LDEO's modeling
methodology is described in greater detail in the IHA application (LGL
2017) and we refer to the reader to that document rather than repeating
it here. The estimated distances to the Level B harassment isopleth for
the Kairei's full airgun array and for the single 100-in\3\ airgun are
shown in Table 5.
Table 5--Predicted Radial Distances From R/V Kairei Seismic Source to
Isopleth Corresponding to Level B Harassment Threshold
------------------------------------------------------------------------
Predicted distance to
Source and volume (in\3\) threshold (160 dB re 1
[mu]Pa) (m)
------------------------------------------------------------------------
1 airgun, 100............................. 722
4 strings, 32 airguns, 7,800.............. 9,289
------------------------------------------------------------------------
Predicted distances to Level A harassment isopleths, which vary
based on marine mammal hearing groups (Table 3), were calculated based
on modeling performed by LDEO using the Nucleus software program and
the NMFS User Spreadsheet, described below. The updated acoustic
thresholds for impulsive sounds (such as airguns) contained in the
Technical Guidance (NMFS 2016) were presented as dual metric acoustic
thresholds using both SELcum and peak sound pressure
metrics. As dual metrics, NMFS considers onset of PTS (Level A
harassment) to have occurred when either one of the two metrics is
exceeded (i.e., metric resulting in the largest isopleth). The
SELcum metric considers both level and duration of exposure,
as well as auditory weighting functions by marine mammal hearing group.
In recognition of the fact that the requirement to calculate Level A
harassment ensonified areas could be more technically challenging to
predict due to the duration component and the use of weighting
functions in the new SELcum thresholds, NMFS developed an
optional User Spreadsheet that includes tools to help predict a simple
isopleth that can be used in conjunction with marine mammal density or
occurrence to facilitate the estimation of take numbers.
The values for SELcum and peak SPL for the Kairei airgun
array were derived from calculating the modified farfield signature
(Table 6). 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
[[Page 34370]]
sound sources, such as airgun arrays. UH used the acoustic modeling
developed by LDEO (same as used for Level B takes) with a small grid
step of 1 m in both the inline and depth directions (for example, see
Figure 5 in the IHA application). 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.
Table 6--Modeled Source Levels for R/V Kairei 7,800 in \3\ Airgun Array and 100 in \3\ Airgun Based on Modified
Farfield Signature
----------------------------------------------------------------------------------------------------------------
7,800 in \3\
airgun array 7,800 in \3\ 100 in \3\ 100 in \3\
Functional hearing group (Peak SPLflat) airgun array airgun (Peak airgun
(db) (SELcum) (db) SPLflat) (db) (SELcum) (db)
----------------------------------------------------------------------------------------------------------------
Low frequency cetaceans......................... 256.36 235.01 229.46 208.41
(Lpk,flat: 219 dB; LE,LF,24h: 183 dB)...........
Mid frequency cetaceans......................... 245.59 235.12 229.47 208.44
(Lpk,flat: 230 dB; LE,MF,24h: 185 dB)...........
High frequency cetaceans........................ 256.26 235.16 229.59 209.01
(Lpk,flat: 202 dB; LE,HF,24h: 155 dB)...........
----------------------------------------------------------------------------------------------------------------
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 Kairei's airgun array (modeled in 1 Hz
bands) was used to make adjustments (dB) to the unweighted spectrum
levels, by frequency, according to the weighting functions for each
relevant marine mammal hearing group. These adjusted/weighted spectrum
levels were then converted to pressures (micropascals) 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, a source velocity of 2.315 meters/second, and shot
interval of 21.59 seconds (LGL 2017), potential radial distances to
auditory injury zones were then calculated for SELcum
thresholds. To estimate Peak SPL thresholds, modeling was run for a
single shot and then a high pass filter was applied for each hearing
group. A high pass filter is a type of band band-pass filter, which
pass frequencies within a defined range without reducing amplitude and
attenuate frequencies outside that defined range (Yost 2007). Inputs to
the User Spreadsheet are shown in Table 6; outputs from the User
Spreadsheet in the form of estimated distances to Level A harassment
isopleths are shown in Table 7. The User Spreadsheet used by UH is
shown in Table 3 of the IHA application.
Table 7--Modeled Radial Distances From R/V Kairei 7800 in\3\ Airgun Array and 100 in\3\ Airgun to Isopleths
Corresponding to Level A Harassment Thresholds
----------------------------------------------------------------------------------------------------------------
7,800 in\3\
airgun array 7,800 in\3\ 100 in\3\ 100 in\3\
Functional hearing group (peak SPLflat) airgun array airgun (Peak airgun
(m) (SELcum) (m) SPLflat) (m) (SELcum) (m)
----------------------------------------------------------------------------------------------------------------
Low frequency cetaceans......................... 61.5 752.8 3.2 4.48
(Lpk,flat: 219 dB; LE,LF,24h: 183 dB)...........
Mid frequency cetaceans......................... 0.0 0.0 0.0 n/a
(Lpk,flat: 230 dB; LE,MF,24h: 185 dB)...........
High frequency cetaceans........................ 14.5 1.7 3.7 n/a
(Lpk,flat: 202 dB; LE,HF,24h: 155 dB)...........
----------------------------------------------------------------------------------------------------------------
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
take. However, these tools offer the best way to predict appropriate
isopleths when more sophisticated 3D modeling methods are not
available, and NMFS continues to develop ways to quantitatively refine
these tools and will qualitatively address the output where
appropriate. 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). For most cetacean species, densities calculated by Bradford et
al. (2017) from summer-fall vessel-based surveys that are part of the
Hawaiian Island Cetacean Ecosystem Assessment Survey (HICEAS) were
used. The surveys were conducted by NMFS' Southwest Fisheries Science
Center (SWFSC) and Pacific Islands Fisheries Science Center (PIFSC) in
2010 using two NOAA research vessels, one during August 13-December 1
and the other during September 2-October 29. The densities were
estimated using a multiple-covariate line-transect approach (Buckland
et al. 2001; Marques and
[[Page 34371]]
Buckland 2004). Density estimates for pygmy and dwarf sperm whales and
spinner dolphins, which were not calculated from the 2010 surveys, were
derived from the ``Outer EEZ stratum'' of the vessel-based HICEAS
survey conducted in summer-fall 2002 by SWFSC (Barlow 2006) using line-
transect methodology (Buckland et al. 2001). The density estimate for
the false killer whale was based on the pelagic stock density
calculated by Bradford et al. (2015) using line-transect methodology
(Buckland et al. 2001).
All densities were corrected for trackline detection probability
bias (f(0)) and availability (g(0)) bias by the authors. Bradford et
al. (2017) used g(0) values estimated by Barlow (2015), whose analysis
indicated that g(0) had previously been overestimated, particularly for
high sea states. Barlow (2006) used earlier estimates of g(0), so
densities used here for pygmy and dwarf sperm whales and spinner
dolphins likely are underestimates. The density for the ``Sei or
Bryde's whale'' category identified by Bradford et al. (2017) was
allocated between sei and Bryde's whales according to their
proportionate densities. Density estimates for humpback and minke
whales were not available.
There is some uncertainty related to the estimated density data and
the assumptions used in their calculations, as with all density data
estimates. However, the approach used is based on the best available
data.
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 B harassment or Level A harassment, radial
distances to predicted isopleths corresponding to the Level A
harassment and Level B harassment thresholds are calculated, as
described above. We then use those distances to calculate the area(s)
around the airgun array predicted to be ensonified to sound levels that
exceed the Level A and Level B harassment thresholds. The total
ensonified area for the survey is then calculated, based on the areas
predicted to be ensonified around the array and the trackline distance.
The marine mammals predicted to occur within these respective areas,
based on estimated densities, are expected to be incidentally taken by
the proposed survey.
To summarize, the estimated density of each marine mammal species
within an area (animals/km\2\) is multiplied by the daily ensonified
areas (km\2\) that correspond to the Level A and Level B harassment
thresholds for the species. The product (rounded) is the number of
instances of take for each species within one day. The number of
instances of take for each species within one day is then multiplied by
the number of survey days (plus 25 percent contingency, as described
below). The result is an estimate of the number of instances that
marine mammals are predicted to be exposed to airgun sounds above the
Level B harassment threshold and the Level A harassment threshold over
the duration of the proposed survey. Estimated takes for all marine
mammal species are shown in Table 8.
The proposed survey would occur both within the U.S. EEZ and
outside the U.S. EEZ. We propose to authorize incidental take that is
expected to occur as a result of the proposed survey both within and
outside the U.S. EEZ.
Table 8--Numbers of Potential Incidental Take of Marine Mammals Proposed for Authorization
----------------------------------------------------------------------------------------------------------------
Total
Proposed Level
Estimated and Estimated Proposed Level Total proposed A and Level B
Species proposed Level Level B takes B takes Level A and takes as a
A takes Level B takes percentage of
population
----------------------------------------------------------------------------------------------------------------
Humpback whale \1\.............. 0 0 2 2 <0.1
Minke whale \1\................. 0 0 1 1 n/a
Bryde's whale................... 2 25 25 27 3.4
Sei whale....................... 0 6 6 6 3.4
Fin whale....................... 0 2 2 2 3.4
Blue whale \1\.................. 0 1 3 3 3.7
Sperm whale..................... 0 51 51 51 1.5
Cuvier's beaked whale........... 0 8 8 8 <0.1
Longman's beaked whale.......... 0 85 85 85 1.9
Blainville's beaked whale....... 0 76 76 76 3.3
Rough-toothed dolphin........... 0 812 812 812 12.9
Bottlenose dolphin.............. 0 246 246 246 4.1
Pantropical spotted dolphin..... 0 639 639 639 4.0
Spinner dolphin \1\............. 0 23 32 32 0.9
Striped dolphin................. 0 685 685 685 3.3
Fraser's dolphin................ 0 577 577 577 3.4
Risso's dolphin................. 0 130 130 130 1.8
Melon-headed whale.............. 0 97 97 97 1.7
Pygmy killer whale.............. 0 119 119 119 3.5
False killer whale.............. 0 16 16 16 1.0
Killer whale \1\................ 0 2 5 5 4.9
Short-finned pilot whale........ 0 218 218 218 1.8
Pygmy sperm whale............... 0 87 87 87 1.2
Dwarf sperm whale............... 0 214 214 214 1.2
----------------------------------------------------------------------------------------------------------------
\1\ The proposed number of authorized takes (Level B harassment only) for these species has been increased from
the calculated take to mean group size. Sources for mean group sizes are as follows: blue whale (Bradford et
al. 2017); minke whale (Jackson et al. 2008); humpback whale (Mobley et al. 2001); spinner dolphin (Barlow
2006); killer whale (Bradford et al. 2017).
[[Page 34372]]
Species With Take Estimates Less Than Mean Group Size: Using the
approach described above to estimate take, the take estimates for the
blue whale, killer whale, and spinner dolphin (Table 8) were less than
the average group sizes estimated for these species. However,
information on the social structures and life histories of these
species indicates it is common for them to be encountered in groups. As
the results of take calculations support the likelihood that UH's
survey would be expected to encounter and to incidentally take these
species, and we believe it is likely that these species may be
encountered in groups, it is reasonable to conservatively assume that
one group of each of these species will be taken during the proposed
survey. We therefore propose to authorize the take of the average
(mean) group size for the blue whale, killer whale, and spinner dolphin
to account for the possibility that UH's survey encounters a group of
any of these species (Table 8).
Species With No Available Density Data: No density data were
available for humpback and minke whales. Both species would typically
be found further north than the proposed survey area during the time of
year that the proposed survey is planned to occur, based on sightings
data around the Hawaiian Islands (Carretta et al. 2017). However, based
on input from subject matter experts, we believe it is reasonable to
assume that both species may be encountered by UH during the proposed
survey. Humpback whales have typically not been observed in the project
area in the fall (Carretta et al. 2017). However, there are increasing
anecdotal reports of confirmed sightings of humpback whales from early
September through October in areas near the planned project area (pers.
comm. E. Lyman, NOAA Office of National Marine Sanctuaries, to J.
Carduner, NMFS, June 20, 2017). Like humpback whales, sightings data
does not indicate that minke whales would typically be expected to be
present in the project area in the fall (Carretta et al. 2017).
However, detections of minke whales are common in passive acoustic
recordings from various locations around the main Hawaiian Islands,
including during the fall (pers. comm. E. Oleson, NOAA PIFSC, to J.
Carduner, NMFS, June 20, 2017). Additionally, as minke whales in the
North Pacific do not have a visible blow, they can be easily missed by
visual observers, suggesting a lack of sightings is likely related to
misidentification or low detection capability in poor sighting
conditions (Rankin et al. 2007). Though no density data are available,
we believe it is reasonable to conservatively assume that UH's proposed
survey may encounter and incidentally take minke and humpback whales.
We therefore propose to authorize the take of the average (mean) group
size (weighted by effort and rounded up) for the humpback and minke
whale (Table 8).
It should be noted that the proposed take numbers shown in Table 8
are believed to be conservative for several reasons. First, in the
calculations of estimated take, 25% has been added in the form of
operational survey days (equivalent to adding 25% to the proposed line
km to be surveyed) 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. Additionally, marine
mammals would be expected to move away from a sound source that
represents an aversive stimulus. 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 take estimates shown in Table 8.
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, and, in the case of a military readiness activity,
personnel safety, practicality of implementation, and impact on the
effectiveness of the military readiness activity.
UH 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, UH has proposed to implement the
following mitigation measures for marine mammals:
(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) Ship strike avoidance measures.
Vessel-Based Visual Mitigation Monitoring
PSO observations would take place during all daytime airgun
operations and nighttime start ups (if applicable) of the airguns.
Airgun operations would be suspended when marine mammals are observed
within, or about to enter, designated Exclusion Zones (as described
below). PSOs would also watch for marine mammals near the seismic
vessel for at least 30 minutes prior to the planned start of airgun
operations. Observations would also be made during daytime periods when
the Kairei is underway without seismic operations, such as during
transits, to allow for comparison of sighting rates and behavior with
and without airgun operations and between acquisition periods.
[[Page 34373]]
During seismic operations, four visual PSOs would be based aboard
the Kairei. PSOs would be appointed by JAMSTEC with NMFS approval.
During the majority of seismic operations, two PSOs would monitor for
marine mammals around the seismic vessel. Use of two simultaneous
observers would increase the effectiveness of detecting marine mammals
around the source vessel. However, during meal times, only one PSO may
be on duty. PSO(s) would be on duty in shifts of duration no longer
than 4 hours. Other crew would also be instructed to assist in
detecting marine mammals and in implementing mitigation requirements
(if practical). Before the start of the seismic survey, the crew would
be given additional instruction in detecting marine mammals and
implementing mitigation requirements. The Kairei is a suitable platform
for marine mammal observations. When stationed on the observation
platform, the PSO would have a good view around the entire vessel.
During daytime, the PSO(s) would scan the area around the vessel
systematically with reticle binoculars (e.g., 7x50 Fujinon), Big-eye
binoculars (25x150), and with the naked eye.
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 would be provided to NMFS for
approval. At least two PSOs must have a minimum of 90 days at-sea
experience working as PSOs during a deep penetration seismic survey,
with no more than eighteen months elapsed since the conclusion of the
at-sea experience. One ``experienced'' visual PSO would be designated
as the lead for the entire protected species observation team. The lead
would coordinate duty schedules and roles for the PSO team and serve as
primary point of contact for the vessel operator. The lead PSO would
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, to the maximum extent practicable
The PSOs must have successfully completed relevant training,
including completion of all required coursework and passing a written
and/or oral examination developed for the training program, and must
have successfully attained a bachelor's degree from an accredited
college or university with a major in one of the natural sciences and a
minimum of 30 semester hours or equivalent in the biological sciences
and at least one undergraduate course in math or statistics. The
educational requirements may be waived if the PSO has acquired the
relevant skills through alternate training, including (1) secondary
education and/or experience comparable to PSO duties; (2) previous work
experience conducting academic, commercial, or government-sponsored
marine mammal surveys; or (3) previous work experience as a PSO; the
PSO should demonstrate good standing and consistently good performance
of PSO duties.
In summary, a typical daytime cruise would have scheduled two
observers (visual) on duty from the observation platform, and an
acoustic observer on the passive acoustic monitoring system.
Vessel-Based Passive Acoustic Mitigation Monitoring
Passive acoustic monitoring (PAM) would take place to complement
the visual monitoring program. Visual monitoring typically is not
effective during periods of poor visibility or at night, and even with
good visibility, is unable to detect marine mammals when they are below
the surface or beyond visual range. Acoustic monitoring can be used in
addition to visual observations to improve detection, identification,
and localization of cetaceans. The acoustic monitoring would serve to
alert visual observers (if on duty) when vocalizing cetaceans are
detected. It is only useful when marine mammals vocalize, but it can be
effective either by day or by night and does not depend on good
visibility. It would be monitored in real time so that visual observers
can be alerted when marine mammals are detected acoustically.
The PAM system consists of hardware (i.e., hydrophones) and
software. The ``wet end'' of the system consists of a towed hydrophone
array that is connected to the vessel by a tow cable. A deck cable
would connect the tow cable to the electronics unit on board where the
acoustic station, signal conditioning, and processing system would be
located. The acoustic signals received by the hydrophones are
amplified, digitized, and then processed by the software.
One acoustic PSO (in addition to the four visual PSOs) would be on
board. The towed hydrophones would be monitored 24 hours per day
(either by the acoustic PSO or by a visual PSO trained in the PAM
system if the acoustic PSO is on break) while at the seismic survey
area during airgun operations, and during most periods when the Kairei
is underway while the airguns are not operating. However, PAM may not
be possible if damage occurs to the array or back-up systems during
operations. One PSO would monitor the acoustic detection system at any
one time, in shifts no longer than six hours, by listening to the
signals via headphones and/or speakers and watching the real-time
spectrographic display for frequency ranges produced by cetaceans.
When a vocalization is detected, while visual observations are in
progress, the acoustic PSO would contact the visual PSOs immediately,
to alert them to the presence of marine mammals (if they have not
already been detected visually), in order to facilitate a power down or
shut down, if required. The information regarding the marine mammal
acoustic detection would be entered into a database.
Exclusion Zone and Buffer Zone
An exclusion zone 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 exclusion zone
with a 500 m radius for the full 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, enters, or appears on a course to enter this zone, the acoustic
source would be powered down (see Power Down Procedures below). In
addition to the 500 m EZ for the full array, a 100 m exclusion zone
would be established for the single 100 in\3\ airgun. With certain
exceptions (described below), if a marine mammal appears within,
enters, or appears on a course to enter this zone the acoustic source
would be shut down entirely (see Shutdown Procedures below).
Potential radial distances to auditory injury zones were calculated
on the basis of maximum peak pressure using values provided by the
applicant (Table 7). The 500 m radial distance of the standard EZ is
intended to be precautionary in the sense that it would be expected to
contain sound exceeding peak pressure injury criteria for all cetacean
hearing groups, while also providing a consistent, reasonably
observable zone within which PSOs would typically be able to conduct
effective observational effort. Although significantly greater
distances may be observed from an elevated platform under good
conditions, we believe that 500 m is likely regularly attainable for
[[Page 34374]]
PSOs using the naked eye during typical conditions.
An appropriate EZ based on cumulative sound exposure level
(SELcum) criteria would be dependent on the animal's applied
hearing range and how that overlaps with the frequencies produced by
the sound source of interest (i.e., via marine mammal auditory
weighting functions) (NMFS, 2016), and may be larger in some cases than
the zones calculated on the basis of the peak pressure thresholds (and
larger than 500 m) depending on the species in question and the
characteristics of the specific airgun array. In particular, the EZ
radii would be larger for low-frequency cetaceans, because their most
susceptible hearing range overlaps the low frequencies produced by
airguns, but the zones would remain very small for mid-frequency
cetaceans (i.e., including the ``small delphinoids'' described below),
whose range of best hearing largely does not overlap with frequencies
produced by airguns.
Consideration of exclusion zone distances is inherently an
essentially instantaneous proposition--a rule or set of rules that
requires mitigation action upon detection of an animal. This indicates
that consideration of peak pressure thresholds is most relevant, as
compared with cumulative sound exposure level thresholds, as the latter
requires that an animal accumulate some level of sound energy exposure
over some period of time (e.g., 24 hours). A PSO aboard a mobile source
will typically have no ability to monitor an animal's position relative
to the acoustic source over relevant time periods for purposes of
understanding whether auditory injury is likely to occur on the basis
of cumulative sound exposure and, therefore, whether action should be
taken to avoid such potential. Therefore, definition of an exclusion
zone based on SELcum thresholds is of questionable relevance
given relative motion of the source and receiver (i.e., the animal).
Cumulative SEL thresholds are likely more relevant for purposes of
modeling the potential for auditory injury than they are for informing
real-time mitigation. We recognize the importance of the accumulation
of sound energy to an understanding of the potential for auditory
injury and that it is likely that, at least for low-frequency
cetaceans, some potential auditory injury is likely impossible to
mitigate and should be considered for authorization.
In summary, our intent in prescribing a standard exclusion zone
distance is to (1) encompass zones for most species within which
auditory injury could occur on the basis of instantaneous exposure; (2)
provide additional protection from the potential for more severe
behavioral reactions (e.g., panic, antipredator response) for marine
mammals at relatively close range to the acoustic source; (3) provide
consistency for PSOs, who need to monitor and implement the exclusion
zone; and (4) to define a distance within which detection probabilities
are reasonably high for most species under typical conditions.
Our use of 500 m as the EZ is a reasonable combination of factors.
This zone would contain all potential auditory injury for all cetaceans
(high-frequency, mid-frequency and low-frequency functional hearing
groups) as assessed against peak pressure thresholds (NMFS, 2016)
(Table 7), would contain all potential auditory injury for high-
frequency and mid-frequency cetaceans as assessed against
SELcum thresholds (NMFS, 2016) (Table 7), and has been
proven to be practicable through past implementation in seismic surveys
conducted for the oil and gas industry in the Gulf of Mexico (as
regulated by BOEM pursuant to the Outer Continental Shelf Lands Act
(OCSLA) (43 U.S.C. 1331-1356)). In summary, a practicable criterion
such as this has the advantage of simplicity while still providing in
most cases a zone larger than relevant auditory injury zones, given
realistic movement of source and receiver.
The PSOs would also establish and monitor a 1,000-m buffer zone.
During use of the acoustic source, occurrence of marine mammals within
the buffer zone (but outside the exclusion zone) would be communicated
to the operator to prepare for the potential power down or shutdown of
the acoustic source. The buffer zone is discussed further under Ramp Up
Procedures below.
Power Down Procedures
A power down involves decreasing the number of airguns in use such
that the radius of the mitigation zone is decreased to the extent that
marine mammals are no longer in, or about to enter, the 500 m EZ.
During a power down, one 100-in\3\ airgun would be operated. The
continued operation of one 100-in\3\ airgun is intended to alert marine
mammals to the presence of the seismic vessel in the area, and to allow
them to leave the area of the seismic vessel if they choose. In
contrast, a shutdown occurs when all airgun activity is suspended
(shutdown procedures are discussed below). If a marine mammal is
detected outside the 500 m EZ but appears likely to enter the 500 m EZ,
the airguns would be powered down before the animal is within the 500 m
EZ. Likewise, if a mammal is already within the 500 m EZ when first
detected, the airguns would be powered down immediately. During a power
down of the airgun array, the 100-in\3\ airgun would be operated.
Following a power down, 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 the following conditions have been met:
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, or
it has not been seen within the 500 m EZ for 30 min in the
case of mysticetes and large odontocetes, including sperm, pygmy sperm,
dwarf sperm, and beaked whales.
This power down requirement would be in place for all marine
mammals, with the exception of small delphinoids under certain
circumstances. 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 of interacting with
the vessel and/or airgun array (e.g., bow riding). This exception to
the power down requirement would apply solely to specific genera of
small dolphins--Steno, Tursiops, Stenella and Lagenodelphis--and would
only apply if the animals were traveling, including approaching the
vessel. If, for example, an animal or group of animals is stationary
for some reason (e.g., feeding) and the source vessel approaches the
animals, the power down requirement applies. An animal with sufficient
incentive to remain in an area rather than avoid an otherwise aversive
stimulus could either incur auditory injury or disruption of important
behavior. If there is uncertainty regarding identification (i.e.,
whether the observed animal(s) belongs to the group described above) or
whether the animals are traveling, the power down would be implemented.
We propose 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
[[Page 34375]]
below, 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). Please see ``Potential
Effects of the Specified Activity on Marine Mammals'' above for further
discussion of sound metrics and thresholds and marine mammal hearing.
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
Kairei 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.
At any distance, power down of the acoustic source would also be
required upon observation of a large whale (i.e., sperm whale or any
baleen whale) with a calf, or upon observation of an aggregation of
large whales of any species (i.e., sperm whale or any baleen whale)
that does not appear to be traveling (e.g., feeding, socializing,
etc.). These would be the only two potential situations that would
require power down of the array for marine mammals observed beyond the
500 m exclusion zone.
Shut Down Procedures
The single 100-in\3\ operating airgun would be shut down if a
marine mammal is seen within or approaching the 100 m EZ for the single
100-in\3\ airgun. Shutdown would be implemented if (1) an animal enters
the 100 m EZ of the single 100-in\3\ airgun after a power down has been
initiated, or (2) an animal is initially seen within the 100 m EZ of
the single 100-in\3\ airgun when more than one airgun (typically the
full array) is operating. Airgun activity would not resume until the
marine mammal has cleared the 500 m EZ. Criteria for judging that the
animal has cleared the EZ would be as described above.
The shutdown requirement, like the power down requirement, would be
waived for dolphins of the following genera: Steno, Tursiops, Stenella
and Lagenodelphis. The shutdown waiver only applies if the animals are
traveling, including approaching the vessel. If animals are stationary
and the source vessel approaches the animals, the shutdown requirement
would apply. If there is uncertainty regarding identification (i.e.,
whether the observed animal(s) belongs to the group described above) or
whether the animals are traveling, the shutdown would be implemented.
Ramp-Up Procedures
Ramp-up of an acoustic source is intended to provide a gradual
increase in sound levels following a power down or shutdown, enabling
animals to move away from the source if the signal is sufficiently
aversive prior to its reaching full intensity. The ramp-up procedure
involves 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. Ramp-up would be required after the array is
powered down or shut down for any reason.
Ramp-up would begin by activating a single airgun of the smallest
volume in the array and would continue in stages by doubling the number
of active elements at the commencement of each stage, with each stage
of approximately the same duration. This approach to ramp-up
(increments of array elements) is proposed because it is relatively
simple to implement for the operator and is intended to ensure a
perceptible increase in sound output per increment while employing
increments that produce similar degrees of increase at each step.
If airguns have been powered down or shut down due to PSO detection
of a marine mammal within or approaching the 500 m EZ, ramp-up would
not be initiated until all marine mammals have cleared the EZ, during
the day or night. Visual and acoustic PSOs would be required to monitor
during ramp-up. If a marine mammal were detected by visual PSOs within
or approaching the 500 m EZ during ramp-up, a power down (or shut down
if appropriate) would be implemented as though the full array were
operational. Criteria for clearing the EZ would be as described above.
Thirty minutes of pre-clearance observation are required prior to
ramp-up for any power down or shutdown of longer than 30 minutes (i.e.,
if the array were shut down during transit from one line to another).
This 30 minute pre-clearance period may occur during any vessel
activity (i.e., transit). If a marine mammal were observed within or
approaching the 500 m EZ during this pre-clearance period, ramp-up
would not be initiated until all marine mammals cleared the EZ.
Criteria for clearing the EZ would be as described above. If the airgun
array has been shut down for reasons other than mitigation (e.g.,
mechanical difficulty) for a period of less than 30 minutes, it may be
activated again without ramp-up if PSOs have maintained constant visual
and acoustic observation and no visual detections of any marine mammal
have occurred within the buffer zone and no acoustic detections have
occurred.
Ramp-up would be planned to occur during periods of good visibility
when possible. However, ramp-up would be allowed at night and during
poor visibility if the 500 m EZ and 1,000 m buffer zone have been
monitored by visual PSOs for 30 minutes prior to ramp-up and if
acoustic monitoring has occurred for 30 minutes prior to ramp-up with
no acoustic detections during that period.
The operator would be required to notify a designated PSO of the
planned start of ramp-up as agreed-upon with the lead PSO; the
notification time should not be less than 60 minutes prior to the
planned ramp-up. A designated PSO must be notified again immediately
prior to initiating ramp-up procedures and the operator must receive
confirmation from the PSO to proceed. The operator must provide
information to PSOs documenting that appropriate procedures were
followed. Following deactivation of the array for reasons other than
mitigation, the operator would be required to communicate the near-term
operational plan to the lead PSO with justification for any planned
nighttime ramp-up.
Based on our evaluation of the applicant's proposed measures, NMFS
has preliminarily determined that the proposed mitigation measures
provide the means effecting the least practicable impact on the
affected species or stocks and their habitat, paying particular
[[Page 34376]]
attention to rookeries, mating grounds, and areas of similar
significance.
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
proposed action area. Effective reporting is critical both to
compliance as well as ensuring that the most value is obtained from the
required monitoring.
Monitoring and reporting requirements prescribed by NMFS should
contribute to improved understanding of one or more of the following:
Occurrence of marine mammal species or stocks in the area
in which take is anticipated (e.g., presence, abundance, distribution,
density).
Nature, scope, or context of likely marine mammal exposure
to potential stressors/impacts (individual or cumulative, acute or
chronic), through better understanding of: (1) Action or environment
(e.g., source characterization, propagation, ambient noise); (2)
affected species (e.g., life history, dive patterns); (3) co-occurrence
of marine mammal species with the action; or (4) biological or
behavioral context of exposure (e.g., age, calving or feeding areas).
Individual marine mammal responses (behavioral or
physiological) to acoustic stressors (acute, chronic, or cumulative),
other stressors, or cumulative impacts from multiple stressors.
How anticipated responses to stressors impact either: (1)
Long-term fitness and survival of individual marine mammals; or (2)
populations, species, or stocks.
Effects on marine mammal habitat (e.g., marine mammal prey
species, acoustic habitat, or other important physical components of
marine mammal habitat).
Mitigation and monitoring effectiveness.
UH submitted a marine mammal monitoring and reporting plan in
section XIII of their IHA application. Monitoring that is designed
specifically to facilitate mitigation measures, such as monitoring of
the EZ to inform potential power downs or shutdowns of the airgun
array, are described above and are not repeated here.
UH's monitoring and reporting plan includes the following measures:
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, four visual PSOs would be based
aboard the Kairei. PSOs would be appointed by JAMSTEC with NMFS
approval. During the majority of seismic operations, two PSOs would
monitor for marine mammals around the seismic vessel. Use of two
simultaneous observers would increase the effectiveness of detecting
animals around the source vessel. However, during meal times, only one
PSO may be on duty. PSOs would be on duty in shifts of duration no
longer than 4 hours. Other crew would also be instructed to assist in
detecting marine mammals and in implementing mitigation requirements
(if practical). During daytime, PSOs would scan the area around the
vessel systematically with reticle binoculars (e.g., 7x50 Fujinon),
Big-eye binoculars (25x150), and with the naked eye.
PSOs would record data to estimate the numbers of marine mammals
exposed to various received sound levels and to document apparent
disturbance reactions or lack thereof. Data would be used to estimate
numbers of animals potentially `taken' by harassment (as defined in the
MMPA). They would also provide information needed to order a power down
or shut down of the airguns when a marine mammal or sea turtle is
within or near the EZ.
When a sighting is made, the following information about the
sighting would be recorded:
1. Species, group size, age/size/sex categories (if determinable),
behavior when first sighted and after initial sighting, heading (if
consistent), bearing and distance from seismic vessel, sighting cue,
apparent reaction to the airguns or vessel (e.g., none, avoidance,
approach, paralleling, etc.), and behavioral pace.
2. Time, location, heading, speed, activity of the vessel, sea
state, visibility, and sun glare.
All observations and power downs or shutdowns would be recorded in
a standardized format. Data would be entered into an electronic
database. The accuracy of the data entry would be verified by
computerized data validity checks as the data are entered and by
subsequent manual checking of the database. These procedures would
allow initial summaries of data to be prepared during and shortly after
the field program and would facilitate transfer of the data to
statistical, graphical, and other programs for further processing and
archiving. The time, location, heading, speed, activity of the vessel,
sea state, visibility, and sun glare would also be recorded at the
start and end of each observation watch, and during a watch whenever
there is a change in one or more of the variables.
Results from the vessel-based observations would provide:
1. The basis for real-time mitigation (airgun power down or shut
down).
2. Information needed to estimate the number of marine mammals
potentially taken by harassment, which must be reported to NMFS.
3. Data on the occurrence, distribution, and activities of marine
mammals and turtles in the area where the seismic study is conducted.
4. Information to compare the distance and distribution of marine
mammals and turtles relative to the source vessel at times with and
without seismic activity.
5. Data on the behavior and movement patterns of marine mammals and
turtles seen at times with and without seismic activity.
Vessel-Based Passive Acoustic Monitoring
PAM would take place to complement the visual monitoring program as
described above. Please see the Proposed Mitigation section above for a
description of the PAM system and the acoustic PSO's duties. The
acoustic PSO would record data collected via the PAM system, including
the following: An acoustic encounter identification number, whether it
was linked with a visual sighting, date, time when first and last heard
and whenever any additional information was recorded, position and
water depth when first detected, bearing if determinable, species or
species group (e.g., unidentified dolphin, sperm whale), types and
nature of sounds heard (e.g., clicks, continuous, sporadic, whistles,
creaks, burst pulses, strength of signal, etc.), and any other notable
information. Acoustic detections would also be recorded for further
analysis.
Reporting
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,
[[Page 34377]]
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.
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 the species listed
in Table 2, given that NMFS expects the anticipated effects of the
proposed seismic survey to be similar in nature. Where there are
meaningful differences between species or stocks, or groups of species,
in anticipated individual responses to activities, impact of expected
take on the population due to differences in population status, or
impacts on habitat, NMFS has identified species-specific factors to
inform the analysis.
NMFS does not anticipate that serious injury or mortality would
occur as a result of UH's proposed seismic 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 one marine mammal species (Table 8). 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 and not
total deafness that would not be likely to affect the fitness of any
individuals, because of the constant movement of both the Kairei and of
the marine mammals in the project area, 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 Kairei'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 area; therefore, marine mammals that
may be temporarily displaced during survey activities are expected to
be able to resume foraging once they have moved away from areas with
disturbing levels of underwater noise. Because of the temporary nature
of the disturbance, the availability of similar habitat and resources
in the surrounding area, and the lack of important or unique marine
mammal habitat, the impacts to marine mammals and the food sources that
they utilize are not expected to cause significant or long-term
consequences for individual marine mammals or their populations. In
addition, there are no mating or calving areas known to be biologically
important to marine mammals within the proposed project area.
The activity is expected to impact a very small percentage of all
marine mammal stocks that would be affected by UH's proposed survey
(less than 2 percent for all marine mammal stocks). Additionally, the
acoustic ``footprint'' of the proposed survey would be very small
relative to the ranges of all 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 seismic array
would be active 24 hours per day throughout the duration of the
proposed survey. However, the very brief overall duration of the
proposed survey (5.5 days) would further limit potential impacts that
may occur as a result of the proposed activity.
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.
Of the marine mammal species under our jurisdiction that are likely
to occur in the project area, the following species are listed as
endangered under the ESA: Blue, fin, sei, and sperm whales. There are
currently insufficient data to determine population trends for blue,
fin, sei, and sperm whales (Carretta et al., 2016); however, we are
proposing to authorize very small numbers of takes for these species
(Table 8), 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 UH's
seismic survey
[[Page 34378]]
are not listed as threatened or endangered under the ESA. There is no
designated critical habitat for any ESA-listed marine mammals within
the project area; and of the non-listed marine mammals for which we
propose to authorize take, none are considered ``depleted'' or
``strategic'' by NMFS under the MMPA.
NMFS concludes that exposures to marine mammal species and stocks
due to UH's proposed seismic survey would result in only short-term
(temporary and short in duration) effects to individuals exposed.
Animals may temporarily avoid the immediate area, but are not expected
to permanently abandon the area. Major shifts in habitat use,
distribution, or foraging success are not expected. NMFS does not
anticipate the proposed take estimates to impact annual rates of
recruitment or survival.
In summary and as described above, the following factors primarily
support our preliminary determination that the impacts resulting from
this activity are not expected to adversely affect the marine mammal
species or stocks through effects on annual rates of recruitment or
survival:
No mortality is anticipated or authorized;
The anticipated impacts of the proposed activity on marine
mammals would primarily be temporary behavioral changes due to
avoidance of the area around the survey vessel. The relatively short
duration of the proposed survey (5.5 days) would further limit the
potential impacts of any temporary behavioral changes that would occur;
PTS is only anticipated to occur for one species and the
number of instances of PTS that may occur are expected to be very small
in number (Table 8). Instances of PTS that are incurred in marine
mammals would be of a low level, due to constant movement of the vessel
and of the marine mammals in the area, and the nature of the survey
design (not concentrated in areas of high marine mammal concentration);
The availability of alternate areas of similar habitat
value for marine mammals to temporarily vacate the survey area during
the proposed survey to avoid exposure to sounds from the activity;
The proposed project area does not contain areas of
significance for mating or calving;
The potential adverse effects on fish or invertebrate
species that serve as prey species for marine mammals from the proposed
survey would be temporary and spatially limited;
The proposed mitigation measures, including visual and
acoustic monitoring, power-downs, and shutdowns, are expected to
minimize potential impacts to marine mammals.
Based on the analysis contained herein of the likely effects of the
specified activity on marine mammals and their habitat, and taking into
consideration the implementation of the proposed monitoring and
mitigation measures, NMFS preliminarily finds that the total marine
mammal take from the proposed activity will have a negligible impact on
all affected marine mammal species or stocks.
Small Numbers
As noted above, only small numbers of incidental take may be
authorized under Section 101(a)(5)(D) of the MMPA for specified
activities other than military readiness activities. The MMPA does not
define small numbers; so, in practice, where estimated numbers are
available, NMFS compares the number of individuals taken to the most
appropriate estimation of abundance of the relevant species or stock in
our determination of whether an authorization is limited to small
numbers of marine mammals. Additionally, other qualitative factors may
be considered in the analysis, such as the temporal or spatial scale of
the activities. Table 8 provides 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 authorization to
be taken, for all species and stocks, would be considered small
relative to the relevant stocks or populations (approximately 13
percent for rough-toothed dolphin, and less than five percent for all
other species and stocks). For the blue whale, killer whale, humpback
whale, minke whale and spinner dolphin we propose to authorize take
resulting from a single exposure of one group of each species or stock,
as appropriate (using best available information on mean group size for
these species or stocks). We believe that a single incident of take of
one group of any of these species represents take of small numbers for
that species
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 or stocks.
Unmitigable Adverse Impact Analysis and Determination
There are no relevant subsistence uses of the affected marine
mammal stocks or species implicated by this action. Therefore, NMFS has
preliminarily 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 four species of marine mammals which
are listed under the ESA: the sei, fin, blue and sperm whale. 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 UH for conducting a seismic survey in the central
Pacific Ocean in September, 2017, 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 the University of Hawaii's (UH) IHA application and
using an array aboard the R/V Kairei with characteristics specified in
the application, in the Central Pacific Ocean.
3. General Conditions
(a) A copy of this IHA must be in the possession of UH, the vessel
operator and other relevant personnel, the lead
[[Page 34379]]
protected species observer (PSO), and any other relevant designees of
UH operating under the authority of this IHA.
(b) The species authorized for taking are listed in Table 8. The
taking, by Level A and Level B harassment only, is limited to the
species and numbers listed in Table 8. Any taking exceeding the
authorized amounts listed in Table 8 is prohibited and may result in
the modification, suspension, or revocation of this IHA.
(c) 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.
(d) During use of the airgun(s), if marine mammal species other
than those listed in Table 8 are detected by PSOs, the acoustic source
must be shut down to avoid unauthorized take.
(e) UH shall ensure that the vessel operator and other relevant
vessel personnel are briefed on all responsibilities, communication
procedures, marine mammal monitoring protocol, operational procedures,
and IHA requirements prior to the start of survey activity, and when
relevant new personnel join the survey operations.
4. Mitigation Requirements
The holder of this Authorization is required to implement the
following mitigation measures:
(a) UH must use five dedicated, trained, NMFS-approved Protected
Species Observers (PSOs), including four visual PSOs and one acoustic
PSO. 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.
(b) At least two PSOs must have a minimum of 90 days at-sea
experience working as PSOs during a deep penetration seismic survey,
with no more than eighteen months elapsed since the conclusion of the
at-sea experience. At least one of these must have relevant experience
as a visual PSO and at least one must have relevant experience as an
acoustic PSO. One ``experienced'' visual PSO 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. 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, to the maximum extent practicable.
(c) Visual Observation
(i) During survey operations (e.g., any day on which use of the
acoustic source is planned to occur; whenever the acoustic source is in
the water, whether activated or not), two 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) with the limited exception of meal times during which one PSO
may be on duty.
(ii) Visual monitoring must begin not less than 30 minutes prior to
ramp-up, including for nighttime ramp-ups of the airgun array, and must
continue until one hour after use of the acoustic source ceases or
until 30 minutes past sunset.
(iii) 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.
(iv) Visual PSOs shall communicate all observations to the acoustic
PSO, including any determination by the PSO regarding species
identification, distance, and bearing and the degree of confidence in
the determination.
(v) Visual 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 observation per 24 hour period.
(vi) During good conditions (e.g., daylight hours; Beaufort sea
state 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.
(d) Acoustic Observation--The R/V Kairei must use a towed passive
acoustic monitoring (PAM) system, which must be monitored beginning at
least 30 minutes prior to ramp-up and at all times during use of the
acoustic source.
(i) One acoustic PSO (in addition to the four visual PSOs) must be
on board to operate and oversee PAM operations. Either the acoustic PSO
or a visual PSO with training in the PAM system must monitor the PAM
system at all times while airguns are operating, and when possible
during periods when the airguns are not operating, in shifts lasting no
longer than six hours.
(ii) Acoustic PSOs shall 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) Survey activity may continue for brief periods of time if the
PAM system malfunctions or is damaged. Activity may continue for 30
minutes without PAM 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 under the following conditions:
(A) Daylight hours and sea state is less than or equal to Beaufort
sea state 4;
(B) No marine mammals (excluding small delphinids) detected solely
by PAM in the 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 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--PSOs shall establish and
monitor a 500 m exclusion zone (EZ) and 1,000 m buffer zone. The zones
shall be based upon radial distance from any element of the airgun
array (rather than being based on the center of the array or around the
vessel itself). During use of the acoustic source, occurrence of marine
mammals outside the EZ but within 1,000 m from any element of the
airgun array shall be communicated to the operator to prepare for
potential further mitigation measures as described below. During use of
the acoustic source, occurrence of marine mammals within the EZ, or on
a course to enter the EZ, shall trigger further mitigation measures as
described below.
(i) Ramp-up--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.
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.
(ii) If the airgun array has been powered down or shut down due to
a marine mammal detection, ramp-up shall not occur until all marine
mammals have cleared the EZ. A marine mammal is considered to have
cleared the EZ if:
[[Page 34380]]
(A) It has been visually observed to have left the EZ
(B) It has not been observed within the EZ, for 15 minutes (in the
case of small odontocetes) or for 30 minutes (in the case of mysticetes
and large odontocetes including sperm, pygmy sperm, dwarf sperm, and
beaked whales).
(iii) Thirty minutes of pre-clearance observation of the 500 m EZ
and 1,000 m buffer zone are required prior to ramp-up for any power
down or shutdown of longer than 30 minutes. This pre-clearance period
may occur during any vessel activity. If any marine mammal (including
delphinids) is observed within or approaching the 500 m EZ during the
30 minute pre-clearance period, ramp-up may not begin until the
animal(s) has been observed exiting the buffer zone or until an
additional time period has elapsed with no further sightings (i.e., 15
minutes for small odontocetes and 30 minutes for all other species).
(iv) During ramp-up, PSOs shall monitor the 500 m EZ and 1,000 m
buffer zone. Ramp-up may not be initiated if any marine mammal
(including delphinids) is observed within or approaching the 500 m EZ.
If a marine mammal is observed within or approaching the 500 m EZ
during ramp-up, a power down or shutdown shall be implemented as though
the full array were operational. Ramp-up may not begin again until the
animal(s) has been observed exiting the 500 m EZ or until an additional
time period has elapsed with no further sightings (i.e., 15 minutes for
small odontocetes and 30 minutes for all other species).
(v) If the airgun array has been shut down for reasons other than
mitigation (e.g., mechanical difficulty) for a period of less than 30
minutes, it may be activated again without ramp-up if PSOs have
maintained constant visual and acoustic observation and no visual
detections of any marine mammal have occurred within the buffer zone
and no acoustic detections have occurred.
(vi) Ramp-up shall only occur at night and at times of poor
visibility where operational planning cannot reasonably avoid such
circumstances. Ramp-up may occur at night and during poor visibility if
the 500 m EZ and 1,000 m buffer zone have been continually monitored by
visual PSOs for 30 minutes prior to ramp-up with no marine mammal
detections and if acoustic monitoring has occurred for 30 minutes prior
to ramp-up with no acoustic detections during that period.
(vii) The vessel 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. A designated PSO must be notified again immediately
prior to initiating ramp-up procedures and the operator must receive
confirmation from the PSO to proceed.
(f) Power Down Requirements--UH shall power-down the airgun array
if a PSO detects a marine mammal within, approaching, or entering the
500 m EZ. A power down involves a decrease in the number of operational
airguns. During a power down, one 100-in \3\ airgun shall be
continuously operated.
(i) Any PSO on duty has the authority to call for power down of the
airgun array (visual PSOs on duty should be in agreement on the need
for power down before requiring such action). When there is certainty
regarding the need for mitigation action on the basis of either visual
or acoustic detection alone, the relevant PSO(s) must call for such
action immediately.
(ii) When both visual and acoustic PSOs are on duty, all detections
must be immediately communicated to the remainder of the on-duty PSO
team for potential verification of visual observations by the acoustic
PSO or of acoustic detections by visual PSOs and initiation of dialogue
as necessary.
(iii) The operator must establish and maintain clear lines of
communication directly between PSOs on duty and crew controlling the
airgun array to ensure that power down commands are conveyed swiftly
while allowing PSOs to maintain watch.
(iv) When power down is called for by a PSO, the power down must
occur and any dispute resolved only following power down.
(v) The power down requirement is waived for dolphins of the
following genera: Steno, Tursiops, Stenella and Lagenodelphis. The
power down waiver only applies if animals are traveling, including
approaching the vessel. If animals are stationary and the vessel
approaches the animals, the power down requirement applies. If there is
uncertainty regarding identification (i.e., whether the observed
animal(s) belongs to the group described above) or whether the animals
are traveling, power down must be implemented.
(vi) Upon implementation of a power down, the source may be
reactivated under the conditions described at 4(e)(vi). Where there is
no relevant zone (e.g., shutdown due to observation of a calf), a 30-
minute clearance period must be observed following the last observation
of the animal(s).
(vii) Power down of the acoustic source is required upon
observation of a whale (i.e., sperm whale or any baleen whale) with
calf at any distance, with ``calf'' defined as an animal less than two-
thirds the body size of an adult observed to be in close association
with an adult.
(viii) Power down of the acoustic source is required upon
observation of an aggregation (i.e., six or more animals) of large
whales of any species (i.e., sperm whale or any baleen whale) that does
not appear to be traveling (e.g., feeding, socializing, etc.).
(ix) When only the acoustic PSO is on duty and a detection is made,
if there is uncertainty regarding species identification or distance to
the vocalizing animal(s), the airgun array must be powered down as a
precaution.
(g) Shutdown requirements--An exclusion zone of 100 m for the
single 100-in\3\ airgun shall be established and monitored by PSOs. If
a marine mammal is observed within, entering, or approaching the 100 m
exclusion zone for the single 100-in\3\ airgun, whether during
implementation of a power down or during operation of the full airgun
array, all airguns including the 100-in\3\ airgun shall be shut down.
(i) Upon implementation of a shutdown, the source may be
reactivated under the conditions described at 4(e).
(ii) Measures described for power downs under 4(f)(i-v) shall also
apply in the case of a shutdown.
(h) Vessel Strike Avoidance--Vessel operator and crew must maintain
a vigilant watch for all marine mammals and slow down or stop the
vessel or alter course, as appropriate, to avoid striking any marine
mammal. A visual observer aboard the vessel must monitor a vessel
strike avoidance zone around the vessel according to the parameters
stated below. Visual observers monitoring the vessel strike avoidance
zone 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.
(i) The vessel must maintain a minimum separation distance of 100 m
from large whales. The following avoidance measures must be taken if a
large whale is within 100 m of the vessel:
(A) The vessel must reduce speed and shift the engine to neutral,
and must not engage the engines until the whale has moved outside of
the vessel's path and the minimum separation distance has been
established.
(B) If the vessel is stationary, the vessel must not engage engines
until the whale(s) has moved out of the vessel's path and beyond 100 m.
[[Page 34381]]
(ii) The vessel must maintain a minimum separation distance of 50 m
from all other marine mammals, with an exception made for animals
described in 4(g)(v) that approach the vessel. If an animal is
encountered during transit, the vessel shall attempt to remain parallel
to the animal's course, avoiding excessive speed or abrupt changes in
course.
(iii) Vessel speeds must be reduced to 10 knots or less when
mother/calf pairs, pods, or large assemblages of cetaceans are observed
near the vessel.
(i) Miscellaneous Protocols
(i) The airgun array must be deactivated when not acquiring data or
preparing to acquire data, except as necessary for testing. Unnecessary
use of the acoustic source shall be avoided. Notified operational
capacity (not including redundant backup airguns) must not be exceeded
during the survey, except where unavoidable for source testing and
calibration purposes. All occasions where activated source volume
exceeds notified operational capacity must be noticed to the PSO(s) on
duty and fully documented. The lead PSO must be granted access to
relevant instrumentation documenting acoustic source power and/or
operational volume.
(ii) Testing of the acoustic source involving all elements requires
normal mitigation protocols (e.g., ramp-up). Testing limited to
individual source elements or strings does not require ramp-up but does
require pre-clearance.
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 must provide bigeye binoculars (e.g., 25x150; 2.7
view angle; individual ocular focus; height control) of appropriate
quality (i.e., Fujinon or equivalent) solely for PSO use. These shall
be pedestal-mounted on the deck at the most appropriate vantage point
that provides for optimal sea surface observation, PSO safety, and safe
operation of the vessel. The operator must also provide a night-vision
device suited for the marine environment for use during nighttime ramp-
up pre-clearance, at the discretion of the PSOs. At minimum, the device
should feature automatic brightness and gain control, bright light
protection, infrared illumination, and optics suited for low-light
situations.
(b) PSOs must also be equipped with reticle binoculars (e.g., 7x50)
of appropriate quality (i.e., Fujinon or equivalent), GPS, digital
single-lens reflex camera of appropriate quality (i.e., Canon or
equivalent), compass, and any other tools necessary to adequately
perform necessary tasks, including accurate determination of distance
and bearing to observed marine mammals.
(c) PSO Qualifications
(i) PSOs must have successfully completed relevant training,
including completion of all required coursework and passing a written
and/or oral examination developed for the training program.
(ii) PSOs must have successfully attained a bachelor's degree from
an accredited college or university with a major in one of the natural
sciences and a minimum of 30 semester hours or equivalent in the
biological sciences and at least one undergraduate course in math or
statistics. The educational requirements may be waived if the PSO has
acquired the relevant skills through alternate experience. Requests for
such a waiver must include written justification. 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
marine mammal 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--PSOs must use standardized data 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 to resume survey. If required mitigation was not
implemented, PSOs should submit a description of the circumstances. We
require that, at a minimum, the following information be reported:
(i) PSO names and affiliations
(ii) Dates of departures and returns to port with port name
(iii) Dates and times (Greenwich Mean Time) of survey effort and
times corresponding with PSO effort
(iv) Vessel location (latitude/longitude) when survey effort begins
and ends; vessel location at beginning and end of visual PSO duty
shifts
(v) Vessel heading and speed at beginning and end of visual PSO
duty shifts and upon any line change
(vi) Environmental conditions while on visual survey (at beginning
and end of PSO shift and whenever conditions change significantly),
including wind speed and direction, Beaufort sea state, Beaufort wind
force, swell height, weather conditions, cloud cover, sun glare, and
overall visibility to the horizon
(vii) Factors that may be contributing to impaired observations
during each PSO shift change or as needed as environmental conditions
change (e.g., vessel traffic, equipment malfunctions)
(viii) 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-ramp-up survey, ramp-up, shutdown, testing, shooting, ramp-
up completion, end of operations, streamers, etc.)
(ix) If a marine mammal is sighted, the following information
should 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); also note 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, 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 the center point of the acoustic source;
(P) Platform activity at time of sighting (e.g., deploying,
recovering,
[[Page 34382]]
testing, shooting, data acquisition, other)
(Q) Description of any actions implemented in response to the
sighting (e.g., delays, shutdown, ramp-up, speed or course alteration,
etc.); time and location of the action should also be recorded
(x) 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) 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, etc.)
(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), and any
other notable information.
6. Reporting
(a) UH shall submit a draft comprehensive report 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 marine mammals 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 marine mammal
sightings (dates, times, locations, activities, associated survey
activities). Geospatial data regarding locations where the acoustic
source was used must be provided as an ESRI shapefile with all
necessary files and appropriate metadata. In addition to the report,
all raw observational data shall be made available to NMFS. The report
must summarize the data collected as required under condition 5(d) of
this 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 to 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
from NMFS on the draft report.
(b) Reporting injured or dead marine mammals:
(i) In the event that the specified activity clearly causes the
take of a marine mammal in a manner not prohibited by this IHA (if
issued), such as serious injury or mortality, UH shall immediately
cease the specified activities and immediately report the incident to
NMFS. 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 UH to
determine what measures are necessary to minimize the likelihood of
further prohibited take and ensure MMPA compliance. UH may not resume
their activities until notified by NMFS.
(ii) In the event that UH 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), UH shall immediately report
the incident to NMFS. 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 UH to determine whether additional mitigation measures or
modifications to the activities are appropriate.
(iii) In the event that UH 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), UH shall report the incident to
NMFS within 24 hours of the discovery. UH 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 draft authorization, and
any other aspect of this Notice of Proposed IHA for the proposed
seismic survey by UH. Please include with your comments any supporting
data or literature citations to help inform our final decision on the
request for MMPA authorization.
Dated: July 19, 2017.
Catherine Marzin,
Acting Deputy Director, Office of Protected Resources, National Marine
Fisheries Service.
[FR Doc. 2017-15455 Filed 7-21-17; 8:45 am]
BILLING CODE 3510-22-P
