Takes of Marine Mammals Incidental to Specified Activities; Taking Marine Mammals Incidental to a Marine Geophysical Survey in the Southwest Pacific Ocean, 2017/2018, 56120-56149 [2017-25516]
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Federal Register / Vol. 82, No. 226 / Monday, November 27, 2017 / Notices
DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric
Administration
RIN 0648–XF456
Takes of Marine Mammals Incidental to
Specified Activities; Taking Marine
Mammals Incidental to a Marine
Geophysical Survey in the Southwest
Pacific Ocean, 2017/2018
National Marine Fisheries
Service (NMFS), National Oceanic and
Atmospheric Administration (NOAA),
Commerce.
ACTION: Notice; issuance of an incidental
harassment authorization.
AGENCY:
In accordance with the
regulations implementing the Marine
Mammal Protection Act (MMPA) as
amended, notification is hereby given
that NMFS has issued an incidental
harassment authorization (IHA) to
Lamont-Doherty Earth Observatory of
Columbia University (L–DEO) to
incidentally harass, by Level A and
Level B harassment only, marine
mammals during marine geophysical
survey activities in the southwest
Pacific Ocean.
DATES: This Authorization is valid from
October 27, 2017 through October 26,
2018.
SUMMARY:
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:
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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
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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, or 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
NMFS prepared an Environmental
Assessment (EA) and analyzed the
potential impacts to marine mammals
that would result from L–DEO’s planned
surveys. A Finding of No Significant
Impact (FONSI) was signed on October
27, 2017. A copy of the EA and FONSI
is available upon request (see
ADDRESSES).
Summary of Request
On May 17, 2017, NMFS received a
request from L–DEO for an IHA to take
marine mammals incidental to
conducting a marine geophysical survey
in the southwest Pacific Ocean. On
September 13, 2017, we deemed
L–DEO’s application for authorization to
be adequate and complete. L–DEO’s
request is for take of 38 species of
marine mammals by Level B harassment
and Level A harassment. Neither L–DEO
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 Activity
Researchers from California State
Polytechnic University, California
Institute of Technology, Pennsylvania
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State University, University Southern
California, University of Southern
Mississippi, University of Hawaii at
Manoa, University of Texas, and
University of Wisconsin Madison, with
funding from the U.S. National Science
Foundation, propose to conduct three
high-energy seismic surveys from the
research vessel (R/V) Marcus G.
Langseth (Langseth) in the waters of
New Zealand in the southwest Pacific
Ocean in 2017/2018. The NSF-owned
Langseth is operated by L–DEO. One
proposed survey would occur east of
North Island and would use an 18airgun towed array with a total
discharge volume of ∼3,300 cubic inches
(in3). Two other proposed seismic
surveys (one off the east coast of North
Island and one south of South Island)
would use a 36-airgun towed array with
a discharge volume of ∼6,600 in3. The
surveys would take place in water
depths from ∼50 to >5,000 m.
The North Island two-dimensional
(2-D) survey would consist of
approximately 35 days of seismic
operations plus approximately 2 days of
transit and towed equipment
deployment/retrieval. The Langseth
would depart Auckland on
approximately October 26, 2017 and
arrive in Wellington on December 1,
2017. The North Island threedimensional (3-D) survey is proposed
for approximately January 5, 2018–
February 8, 2018 and would consist of
approximately 33 days of seismic
operations plus approximately 2 days of
transit and towed equipment
deployment/retrieval. The Langseth
would leave and return to port in
Napier. The South Island 2-D survey is
proposed for approximately February
15, 2018–March 15, 2018 and would
consist of approximately 22 days of
seismic operations, approximately 3
days of transit, and approximately 7
days of ocean bottom seismometer
(OBS) deployment/retrieval.
The proposed surveys would occur
within the Exclusive Economic Zone
(EEZ) and territorial sea of New
Zealand. The proposed North Island
2-D survey would occur within ∼37–43°
S. between 180° E. and the east coast of
North Island along the Hikurangi
margin. The proposed North Island 3-D
survey would occur over a 15 x 60
kilometer (km) area offshore at the
Hikurangi trench and forearc off North
Island within ∼38–39.5° S., ∼178–179.5°
E. The proposed South Island 2-D
survey would occur along the Puysegur
margin off South Island within ∼163–
168° E. between 50° S. and the south
coast of South Island. Please see Figure
1 and Figure 2 in L–DEO’s IHA
application for maps depicting the
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specified geographic region of the
proposed surveys.
A detailed description of the planned
project is provided in the Federal
Register notice for the proposed IHA (82
FR 45116; September 27, 2017). Since
that time, no changes have been made
to the planned activities. Therefore, a
detailed description is not provided
here. Please refer to that Federal
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Register notice for the description of the
specific activity. Specifications of the
airgun arrays, trackline distances, and
water depths of each of the three
proposed surveys are shown in Table 1.
TABLE 1—SPECIFICATIONS OF AIRGUN ARRAYS, TRACKLINE DISTANCES, AND WATER DEPTHS ASSOCIATED WITH THREE
PLANNED R/V LANGSETH SURVEYS OFF NEW ZEALAND
North Island 2-D survey
North Island 3-D survey
South Island 2-D survey
Airgun array configuration and total
volume.
36 airguns, four strings, total volume of ∼6,600 in3.
36 airguns, four strings, total volume of ∼6,600 in3.
Tow depth of arrays .......................
Shot point intervals ........................
Source velocity (tow speed) ..........
Water depths .................................
9 m ................................................
37.5 m ...........................................
4.3 knots .......................................
8%, 23%, and 69% of line km
would take place in shallow
(<100 m), intermediate (100–
1,000 m), and deep water
(>1,000 m), respectively.
5,398 km .......................................
Approximately 9 percent ...............
two separate 18-airgun arrays
that would fire alternately; each
array would have a total discharge volume of ∼3,300 in3.
9 m ................................................
37.5 m * .........................................
4.5 knots .......................................
0%, 42%, and 58% of line km
would take place in shallow, intermediate, and deep water, respectively.
9 m.
50 m.
4.5 knots.
1%, 17%, and 82% of line km
would take place in shallow, intermediate, and deep water, respectively.
3,025 km .......................................
Approximately 1 percent ...............
4,876 km.
Approximately 6 percent.
Approximate trackline distance ......
Percentage of survey tracklines
proposed in New Zealand Territorial Waters.
* The two arrays fire alternately with an approximate distance of 37.5 m traveled between the firing of one array, then the other.
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Comments and Responses
NMFS published a notice of proposed
IHA in the Federal Register on
September 27, 2017 (82 FR 45116).
During the 30-day public comment
period, NMFS received comments from
the Marine Mammal Commission
(Commission), the Marine Seismic
Research Oversight Committee
(MSROC) and from members of the
general public. NMFS has posted the
comments online at: https://
www.nmfs.noaa.gov/pr/permits/
incidental. The following is a summary
of the public comments and NMFS’
responses.
Comment 1: The Commission
expressed concerns regarding L–DEO’s
method to estimate the extent of the
Level A and B harassment zones and the
numbers of marine mammal takes. The
Commission stated that the model is not
the best available science because it
assumes spherical spreading, a constant
sound speed, and no bottom
interactions for surveys in deep water.
In light of their concerns, the
Commission recommended that NMFS
require L–DEO to re-estimate the Level
A and Level B harassment zones and
associated takes of marine mammals
using both operational (including
number/type/spacing of airguns, tow
depth, source level/operating pressure,
operational volume) and site-specific
environmental (including sound speed
profiles, bathymetry, and sediment
characteristics at a minimum)
parameters.
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NMFS Response: NMFS understands
the concerns expressed by the
Commission about L–DEO’s current
modeling approach for estimating Level
A and Level B harassment zones.
L–DEO has conveyed to NMFS that
additional modeling efforts to refine the
process and conduct comparative
analysis may be possible with the
availability of research funds and other
resources. Obtaining research funds is
typically accomplished through a
competitive process, including those
submitted to U.S. Federal agencies. The
use of models for calculating buffer and
exclusion zone radii and for developing
take estimates is not a requirement of
the MMPA incidental take authorization
process. Furthermore, NMFS does not
provide specific guidance on model
parameters nor prescribe a specific
model for applicants as part of the
MMPA incidental take authorization
process at this time, although we do
review methods to ensure their
adequacy for prediction of take.
L–DEO’s application describes their
approach to modeling Level A and Level
B harassment zones. In summary,
L–DEO acquired field measurements for
several array configurations at shallow,
intermediate, and deep-water depths
during acoustic verification studies
conducted in the northern Gulf of
Mexico in 2007 and 2008; these were
presented in Tolstoy et al. (2009). Based
on the empirical data from those
studies, L–DEO developed a sound
propagation modeling approach that
predicts received sound levels as a
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function of distance from a particular
airgun array configuration in deep water
(Diebold et al., 2010; NSF–USGS 2011).
For the planned surveys off the coast of
New Zealand, L–DEO modeled Level A
and Level B harassment zones using the
sound propagation modeling approach
described in Diebold et al. (2010), based
on the empirically-derived
measurements from the Gulf of Mexico
calibration survey. For deep water
(>1000 meters (m)), L–DEO used the
deep-water radii obtained from model
results down to a maximum water depth
of 2,000 m (Figure 2 and 3 in Diebold
et al., 2010); the radii for intermediate
water depths (100–1,000 m) were
derived from the deep-water radii by
applying a correction factor
(multiplication) of 1.5 (Fig. 16 in
Diebold et al., 2010); the radii for
shallow-water depths (<100 m) were
derived by applying a scaling factor to
the empirically derived measurements
from the Gulf of Mexico calibration
survey (Tolstoy et al., 2009) to account
for the differences in tow depth between
the Gulf of Mexico calibration survey (6
m) and the planned New Zealand
surveys (9 and 12 m).
In 2015, L–DEO explored the question
of whether the Gulf of Mexico
calibration data adequately informs the
model to predict isopleths in other areas
by conducting a retrospective sound
power analysis of one of the lines
acquired during a L–DEO seismic
survey offshore New Jersey in 2014
(Crone, 2015). NMFS presented a
comparison of the predicted radii (i.e.,
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modeled isopleths to distances
corresponding to Level A and Level B
harassment thresholds) with radii based
on in situ measurements in a previous
notice of issued Authorization for
Lamont-Doherty (see 80 FR 27635; May
14, 2015, Table 1).
Briefly, Crone’s (2015) analysis,
specific to the survey site offshore New
Jersey, confirmed that in-situ, site
specific measurements and estimates of
160 decibels (dB) root mean square
(rms) and 180 dB rms isopleths
collected by the Langseth’s hydrophone
streamer in shallow water were smaller
than the modeled (i.e., predicted) zones
for two seismic surveys conducted
offshore New Jersey in shallow water in
2014 and 2015. In that particular case,
Crone’s (2015) results showed that
L–DEO’s modeled 180 dB rms and 160
dB rms zones were approximately 28
percent and 33 percent larger,
respectively, than the in-situ, sitespecific measurements, thus confirming
that L–DEO’s model was conservative in
that case. The following is a summary
of two additional analyses of in-situ
data that support L–DEO’s use of the
modeled Level A and Level B
harassment zones in this particular case.
In 2010, L–DEO assessed the accuracy
of their modeling approach by
comparing the sound levels of the field
measurements acquired in the Gulf of
Mexico study to their model predictions
(Diebold et al., 2010). They reported
that the observed sound levels from the
field measurements fell almost entirely
below the predicted mitigation radii
curve for deep water (greater than 1,000
m; 3280.8 feet (ft)) (Diebold et al., 2010).
In 2012, L–DEO used a similar
process to model distances to isopleths
corresponding to the isopleths
corresponding to Level A and Level B
harassment thresholds for a shallowwater seismic survey in the northeast
Pacific Ocean offshore Washington
State. L–DEO conducted the shallowwater survey using the same airgun
configuration planned for the surveys
considered in this IHA (i.e., 6,600 cubic
inches (in3)) and recorded the received
sound levels on both the shelf and slope
using the Langseth’s 8 kilometer (km)
hydrophone streamer. Crone et al.
(2014) analyzed those received sound
levels from the 2012 survey and
confirmed that in-situ, site specific
measurements and estimates of the 160
dB rms and 180 dB rms isopleths
collected by the Langseth’s hydrophone
streamer in shallow water were two to
three times smaller than L–DEO’s
modeling approach had predicted.
While the results confirmed
bathymetry’s role in sound propagation,
Crone et al. (2014) were also able to
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confirm that the empirical
measurements from the Gulf of Mexico
calibration survey (the same
measurements used to inform L–DEO’s
modeling approach for the planned
surveys in the southwest Pacific Ocean)
overestimated the size of the predicted
isopleths for the shallow-water 2012
survey off Washington State and were
thus precautionary, in that particular
case.
NMFS continues to work with L–DEO
to address the issue of incorporating
site-specific information for future
authorizations for seismic surveys.
However, L–DEO’s current modeling
approach (supported by the three
studies discussed previously) represents
the best available information for NMFS
to reach determinations for this IHA. As
described earlier, the comparisons of
L–DEO’s model results and the field
data collected in the Gulf of Mexico,
offshore Washington State, and offshore
New Jersey illustrate a degree of
conservativeness built into L–DEO’s
model for deep water, which NMFS
expects to offset some of the limitations
of the model to capture the variability
resulting from site-specific factors.
Based upon the best available
information (i.e., the three data points,
two of which are peer-reviewed,
discussed in this response), NMFS finds
that the Level A and Level B harassment
zone calculations are appropriate for use
in this particular IHA. Additionally,
results of acoustic modeling represent
just one component of the analysis
during the MMPA authorization
process, as NMFS also takes into
consideration other factors associated
with the activity (e.g., geographic
location, duration of activities, context,
sound source intensity, etc.).
Comment 2: The Commission
recommended that NMFS use a different
data source to estimate densities of New
Zealand fur seals and southern elephant
seals than was used in the proposed
IHA. Specifically, the Commission
recommended that NMFS rely on the
data presented in the U.S. Navy Marine
Species Density Database (NMSDD) to
estimate take of these pinniped species.
The Commission also recommended
that NMFS convene an internal working
group to determine what data sources
are considered best available for the
various species and in the various areas
and provide that information to
applicants accordingly.
NMFS Response: Density data
presented in Bonnell et al. (1992) was
used in this particular IHA because it
was based on systematic aerial at-sea
surveys (off Oregon and Washington),
whereas the data presented in NMSDD
was derived from surveys of hauled out
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pinnipeds. While the NMSDD data is
more recent than the data presented in
Bonnell et al. (1992), in this case we
determined that densities presented in
Bonnell et al. (1992), which were
derived from at-sea surveys, would be
more representative of densities for
similar taxonomic species in a different
area (in this case, New Zealand). It is
important to note that the NMSDD data
are specific to the west coast of the U.S.
and were based on population sizes for
the species in the particular geographic
ranges for the particular geographic
areas of concern for the U.S. Navy, and
are therefore useful in estimating
densities for those same species in those
same particular geographic areas.
However, in this case the densities
reported for pinnipeds off the U.S. west
coast were used to estimate densities of
surrogate species in a different
geographic area (New Zealand). Thus
our selection of the data from Bonnell
et al. (1992) to extrapolate pinniped
densities in New Zealand for this IHA
was based on a preference to use data
that was based on at-sea surveys to
estimate at-sea density. While we
acknowledge the usefulness of the
NMSDD data for calculating marine
mammal densities for ITAs for activities
that occur on the U.S. west coast, that
does not preclude us from relying on
other data sources when activities are
planned to occur outside the U.S. In
summary, while NMFS has used
NMSDD density data to estimate take of
pinnipeds in previous ITAs for activities
that occurred off the west coast of the
U.S., NMFS determined that, for this
particular IHA, Bonnell et al. (1992)
represented the best available
information for the marine mammals in
the survey area.
Regarding the Commission’s
recommendation that NMFS convene an
internal working group to determine
what data sources are considered best
available for the various species and in
the various areas, NMFS may consider
future action to address these issues, but
currently intends to address these
questions through ongoing interactions
with the U.S. Navy, academic
institutions, and other organizations.
Comment 3: The Commission
recommended that NMFS adjust density
estimates using some measure of
uncertainty (i.e., coefficient of variation,
standard deviation, standard error)
rather than the proposed 25 percent
contingency, and recommended that
NMFS convene a working group to
determine how best to incorporate
uncertainty in density data that are
extrapolated.
NMFS Response: The Commission has
recommended previously that NMFS
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adjust density estimates using some
measure of uncertainty when available
density data originate from different
geographic areas, temporal scales, and
species, especially for actions which
will occur outside the U.S. EEZ where
site- and species-specific density
estimates tend to be scant, such as
L–DEO’s planned survey. We have
attempted to do so in this IHA, and feel
the 25 percent correction factor is an
appropriate method in this case to
account for uncertainties in the density
data that was available for use in the
take estimates. NMFS is open to
consideration of other correction factors
for use in future IHAs and looks forward
to further discussion with the
Commission on how best to incorporate
uncertainty in density estimates in
instances where density data is limited.
Regarding the recommendation that
NMFS convene a working group to
determine how best to incorporate
uncertainty in density data that are
extrapolated, NMFS may consider
future action to address these issues, but
currently intends to address these
questions through ongoing interactions
with the U.S. Navy, academic
institutions, and other organizations.
Comment 4: The Commission
expressed concern regarding methods
used to estimate the numbers of takes,
including the use of rounding in
calculations and recommended that
NMFS share the rounding criteria with
the Commission.
NMFS Response: NMFS appreciates
the Commission’s ongoing concern in
this matter. Calculating predicted takes
is not an exact science and there are
arguments for taking different
mathematical approaches in different
situations, and for making qualitative
adjustments in other situations. We
believe, however, that the methodology
used for take calculation in this IHA, as
described in detail in the Federal
Register notice of the proposed IHA (82
FR 45116; September 27, 2017), remains
appropriate. NMFS continues to refine
the rounding criteria and will share the
criteria with the Commission upon its
finalization.
Comment 5: The Commission
recommended that NMFS authorize
Level A take based on group size of the
species when Level A take is anticipated
and when the estimated Level A take of
a species was less than the group size
for the species.
NMFS Response: NMFS considered
this recommendation but ultimately
concluded that, given the modeled
Level A harassment zones in concert
with the mitigation measures required
in the IHA, it was not realistic to assume
a single take by Level A harassment of
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an individual animal would translate to
an entire group of that species being
taken by Level A harassment, in all
instances. The assumption that if a
single individual is taken then an entire
group would be taken only applies in
the case of instantaneous exposure, as it
is extremely unlikely than an entire
group of animals would remain within
an area long enough to be taken by an
accumulation of energy (SELcum).
Therefore, in analyzing this question,
we only considered the potential for
Level A take of an entire group of the
species in the context of peak sound
pressure level (SPL). The modeled Level
A zones (peak SPL) for marine mammal
functional hearing groups are relatively
small, especially in the cases of lowfrequency cetaceans, mid-frequency
cetaceans, phocid pinnipeds and otariid
pinnipeds, for which the modeled Level
A zones (peak SPL) are all estimated to
be less than 50 m (Tables 6, 7 and 8).
Coupled with the fact that shutdown of
the airguns is required for marine
mammals within 100 m of the array
(with the exception of short-beaked
common dolphins, dusky dolphins and
southern right whale dolphins that
approach the vessel), it is very unlikely
that an entire group of any species of
marine mammals in these functional
hearing groups would be exposed to the
airgun array at levels that would
constitute Level A harassment. For
instance, in the case of short-finned
pilot whales, one take by Level A
harassment is estimated during the
North Island 2-D survey (Table 10).
Though we are not aware of information
on the typical group size for shortfinned pilot whales off New Zealand,
Ross (2006) reported that short-finned
pilot whales off Australia tend to occur
in groups of 10–30 individuals. The
Level A harassment zone (SPL) for
short-finned pilot whales (considered to
be in the mid-frequency functional
hearing group) for the North Island 2-D
survey is estimated to be less than 14 m
(Table 6). We believe the possibility of
a group of 10–30 short-finned pilot
whales approaching within 14 m of the
airgun array and being taken by Level A
harassment, especially considering the
mitigation requirement that the array be
shut down entirely if a pilot whale
approaches within 100 m of the array,
is so low as to be discountable.
Even in the case of short-beaked
common dolphins, dusky dolphins and
southern right whale dolphins that
approach the vessel, for which the
power down requirement does not
apply, we believe the likelihood that a
group of bow-riding dolphins would
occur within 14 m of the array to be so
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low as to be discountable. For instance,
though common dolphin group size
varies depending on season, depth, sea
surface temperature, Stockin (2008)
reported the most frequently observed
group size in the Hauraki Gulf to be 21–
30 animals. We believe the possibility of
a group of 21–30 dolphins approaching
within 14 m of the airgun array and
being taken by Level A harassment is so
low as to be discountable. Therefore, for
the species categorized as low-frequency
cetaceans, mid-frequency cetaceans,
phocid pinnipeds and otariid
pinnipeds, we do not authorize Level A
take by group size, when at least one
take is estimated to occur for the
species.
The Level A harassment zones (peak
SPL) for high-frequency cetaceans are
estimated at 229.2 m, 119.0 m, and
229.2 m, for the North Island 2-D, North
Island 3-D, and South Island 2-D
surveys, respectively. We analyzed the
potential for a group of any of the
species in the high-frequency functional
hearing group (that occur in the survey
areas) occurring between 229.2 m
(largest distance to the isopleth
corresponding to the Level A
harassment threshold) and 100 m (the
distance to the 100 m exclusion zone
(EZ) for the smallest element in the
array, for all species in the highfrequency functional hearing group) of
the array. The species in this group for
which Level A take is authorized in this
IHA include the hourglass dolphin,
spectacled porpoise and pygmy sperm
whale. We are not aware of information
on the group sizes of these species in
the waters off New Zealand. However,
based on the best available information,
estimated group sizes are lower than the
number of takes authorized, when at
least 1 Level A take is authorized, for
these species: Hourglass dolphin group
size was reported as averaging 2–6
individuals in Antarctic waters
(Santora, 2012) whereas 15, 10, and 12
takes by Level A harassment are
authorized (for North Island 2-D, North
Island 3-D, and South Island 2-D survey,
respectively); spectacled porpoise group
size was reported as 2 individuals in
Antarctic waters (Sekiguchi et al., 2006),
whereas 6 takes by Level A harassment
are authorized for the South Island 2-D
survey (with 0 Level A takes predicted
for the North Island 2-D and North
Island 3-D surveys); Kogia spp. mean
group size was reported as 1.9
individuals in the California current
ecosystem (Barlow, 2010) whereas 6, 4,
and 5 takes by Level A harassment are
authorized (for North Island 2-D, North
Island 3-D, and South Island 2-D survey,
respectively). Because the number of
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authorized Level A takes are higher than
the respective group sizes for these
species, we do not authorize Level A
take by group size, when at least one
take is estimated to occur for the
species, for any marine mammal
species.
Comment 6: The Commission
recommended that NMFS include a take
table showing the total numbers of takes
for the entire activity area (territorial
seas, exclusive economic zones, and
high seas).
NMFS Response: NMFS does not
authorize takes in the territorial sea.
However, we have included a table
showing the take estimates in the New
Zealand territorial sea (see Table 14).
Comment 7: The Commission
recommended that NMFS include
pygmy and gingko-toothed beaked
whales and dwarf sperm whales in the
IHA, based on range estimates and
stranding records in New Zealand for
these species.
NMFS Response: NMFS has reviewed
the available literature available on the
strandings of these three species. While
stranding records exist for these species
in various locations on the coast of New
Zealand, these strandings appear to
have been isolated events in all cases
and do not suggest that the density of
these species in the survey area is such
that take of these species is likely to
occur. Therefore, we do not authorize
take of ginkgo-toothed beaked whales,
pygmy beaked whales, and dwarf sperm
whales in this IHA.
Comment 8: The Commission
recommended that NMFS prohibit L–
DEO from using power downs during its
survey.
NMFS Response: NMFS agrees with
the Commission that limiting the use of
power downs can be beneficial in
reducing the overall sound input in the
marine environment from geophysical
surveys; as such, NMFS is requiring that
power downs in this IHA occur for no
more than a maximum of 30 minutes at
any time. NMFS is still in the process
of determining best practice, via
solicitation of public comment, for the
use of power downs as a mitigation
measure in ITAs for geophysical
surveys. We will take into consideration
the Commission’s recommendation that
power downs be eliminated as a
mitigation measure as we work toward
a determination on best practices for the
use of power downs in IHAs for marine
geophysical surveys. Ultimately our
determination will be based on the best
available science and will be
communicated clearly to ITA
applicants.
Comment 9: The Commission
recommended that NMFS condition the
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IHA to require LDEO to abide by the
regulatory requirements of New
Zealand’s Exclusive Economic Zone and
Continental Shelf Act and, through it,
the mandatory provisions of the 2013
Code of Conduct for Minimizing
Acoustic Disturbance to Marine
Mammals from Seismic Survey
Operations (Code).
NMFS Response: NMFS does not have
the statutory authority to require L–DEO
to abide by the regulatory requirements
of New Zealand’s Exclusive Economic
Zone and Continental Shelf Act and,
through it, the mandatory provisions of
the Code. Under the MMPA, L–DEO
must comply with the requirements of
the IHA. However, we also encourage L–
DEO to comply with the provisions of
the Code to the extent possible.
Comment 10: The Commission
recommended that NMFS include a
mitigation measure requiring shutdown
of the airgun array upon observation of
a large whale with calf or an aggregation
of large whales at any distance, in an
effort to minimize impacts on
mysticetes and sperm whales that are
engaged in biologically-important
behaviors (e.g., nursing, breeding,
feeding).
NMFS Response: NMFS has included
mitigation measures in the final IHA
requiring shutdown of the airgun array
upon observation of a large whale with
calf and upon observation of an
aggregation of large whales at any
distance, as recommended by the
Commission. See the section on
Mitigation, below, for more details.
Comment 11: The Commission
recommended that NMFS incorporate
mitigation measures that would require
both visual observations and passive
acoustic methods to implement
shutdown procedures when any sperm
whale, beaked whale, or Kogia spp. are
detected, which would bolster
mitigation efforts as a whole, affording
NMFS the ability to further reduce the
impacts on those deep-diving species.
The Commission also recommended a
consistent approach for requiring all
geophysical and seismic survey
operators to abide by the same general
mitigation measures.
NMFS Response: NMFS has included
a mitigation measure in the final IHA
requiring shutdown of the airgun array
upon acoustic detection of a beaked
whale, sperm whale, or Kogia spp., as
recommended by the Commission, with
an exception for sperm whales in
instances where the acoustic detection
can be definitively localized and the
sperm whale is confirmed to be located
outside the 500 m exclusion zone. See
the Response to Comment 13 and the
section on Mitigation, below, for further
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details, including the reasoning behind
the shutdown requirement upon
acoustic detection and the sperm whale
exception.
NMFS considered requirement of
shutdown upon visual detection of
sperm whales at any distance. We have
included a mitigation measure that
would require shutdown of the array on
acoustic detection of sperm whales at
any distance (except in instances where
the sperm whale can be definitively
localized as being located outside the
500 m EZ). The reasoning behind the
shutdown requirement upon acoustic
detection is provided in more detail
below (see section on Mitigation). Based
on the best available information, we
believe that acoustic detections of sperm
whales would most likely be
representative of the foraging behavior
we intend to minimize disruption of,
while visual observations of sperm
whales would represent resting between
bouts of such behavior. Occurrence of
resting sperm whales at distances
beyond the 500 m exclusion zone may
not indicate a need to implement
shutdown. Therefore, this measure has
not been added to the final IHA. This is
discussed in greater detail in the
Mitigation section, below.
NMFS agrees with the Commission
that consistency in mitigation measures
across incidental take authorizations
(ITAs) for similar activities is a
worthwhile goal, to the extent
practicable. However, NMFS also must
determine the most appropriate
mitigation measures for a given ITA,
taking into account factors unique to
that ITA, such as the type, extent,
location, and timing of activities, and
therefore, complete consistency in
mitigation measures across ITAs for
similar activities will not always be
possible. NMFS is still in the process of
determining best practice, via
solicitation of public comment, for the
use of a suite of mitigation measures in
ITAs for marine geophysical surveys.
We will take into consideration the
Commission’s recommendations with
regard to mitigation measures as we
work toward determinations on best
practices for mitigation measures in
IHAs for geophysical surveys.
Ultimately our determination will be
based on the best available science and
will be communicated clearly to ITA
applicants.
Comment 12: The Commission
expressed concern that reporting of the
manner of taking and the numbers of
animals incidentally taken should
account for all animals in the various
survey areas, including those animals
directly on the trackline that are not
detected, and how well animals are
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detected based on the distance from the
observer (accounted for by g(0) and f(0)
values). The Commission has
recommended a method for estimating
the number of cetaceans in the vicinity
of geophysical surveys based on the
number of groups detected and
recommended that NMFS require
L–DEO to use this method for estimating
g(0) and f(0) values to better estimate the
numbers of marine mammals taken by
Level A and Level B harassment.
NMFS Response: NMFS agrees that
reporting of the manner of taking and
the numbers of animals incidentally
taken should account for all animals
taken, including those animals directly
on the trackline that are not detected
and how well animals are detected
based on the distance from the observer,
to the extent practicable. NMFS
appreciates the Commission’s
recommendations but we believe that
the Commission’s described method
needs further consideration in relation
to the observations conducted during
marine geophysical surveys. Therefore,
at this time we do not prescribe a
particular method for accomplishing
this task. We look forward to engaging
further both L–DEO, the Commission
and other applicants to reach a
determination on the most suitable
method to for estimating g(0) and f(0)
values.
Comment 13: A member of the general
public expressed concern regarding the
effective dates of the IHA and that there
had not been adequate consultation
within New Zealand, including that the
local indigenous populations were not
consulted.
NMFS Response: NMFS has followed
and met its statutory obligations with
respect to notifying the public of, and
requesting comments on, the proposed
IHA, and has considered and responded
to all public comments received. With
respect to concerns regarding
communication within New Zealand,
including with indigenous groups,
NMFS does not have the authority to
require communication between L–DEO
and the New Zealand government or
interested parties within New Zealand.
In addition, the MMPA provides
authority only to authorize the take of
marine mammals that may occur
incidental to the activity; NMFS does
not permit the activity itself. However,
the National Science Foundation, as the
funder of the survey, has been in
communication with the New Zealand
Department of Conservation (NZDOC)
regarding the survey, and
recommendations from the NZDOC
have been incorporated in the IHA. For
instance, the power down waiver for
bottlenose dolphins has been removed
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from the IHA based on input received
from the NZDOC (see the section on
Revisions to the IHA That Have
Occurred Since the Proposed IHA,
below, for details). The comment also
stated that lack of communication with
indigenous groups represents a breach
of the Treaty of Waitangi; however, the
United States is not a Party to the Treaty
of Waitangi.
Comment 14: A member of the general
public expressed concern regarding
potential impacts to marine mammals,
including impacts to mother-calf pairs,
South Island Hector’s dolphins,
southern right whales, blue whales,
killer whales, sperm whales and beaked
whales. The commenter also expressed
concern that tourism companies could
be hurt financially by the planned
surveys
NMFS Response: The commenter
expressed concern that the timing of the
planned surveys overlaps with calving
season for delphinids and that noise
from the planned surveys could
interfere with mother-calf
communication. The commenter did not
provide any detailed or substantive
information or references to support this
statement or change our analyses. We
recognize that restricted communication
as a result of increased noise from
seismic surveys may be of concern,
which is why we have incorporated
mitigation measures to minimize the
potential for this to occur. For instance,
the IHA requires that the airgun array be
shut down upon observation of a large
whale with calf at any distance;
additionally, the airgun array would be
powered down to a single 40 in3 airgun
if any delphinids (other than those that
approach the vessel (i.e., bow ride)) are
detected within 500 m of the array. We
have determined these measures ensure
the least practicable impact on the
species potentially affected. The
commenter expressed concern regarding
potential impacts to blue whales, killer
whales, sperm whales and other deepdiving whales. However, the comments
specific to blue whales, killer whales,
sperm whales and other deep-diving
whales did not include any supporting
information nor did they recommend
any specific action. NMFS believes the
mitigation and monitoring measures
incorporated in the IHA, including
measures specific to sperm whales and
other deep diving cetaceans, ensure the
least practicable impact on the species
potentially affected (see the Mitigation
section, below).
The commenter also expressed
concern regarding South Island Hector’s
dolphins, specifically the subpopulation
that resides in Te Waewae Bay, noting
that they exhibit high site fidelity and
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that the survey will coincide with
Hector’s dolphin calving season. We
agree with the concerns raised by this
comment, especially given the
proximity of the planned track lines of
the South Island 2-D survey to Te
Waewae Bay (see Figure 2 in the IHA
application). In response to this
concern, we have incorporated a
mitigation measure that would require
shutdown of the array upon visual
detection of South Island Hector’s
dolphins at any distance. Based on this
comment, we have also added a
mitigation measure requiring shutdown
of the array upon acoustic detection of
a Hector’s dolphin during North and
South Island surveys, if the acoustic
detection can be definitively identified
as a Hector’s dolphin. More information
is provided below in the section on
Revisions to the IHA That Have
Occurred Since the Proposed IHA.
Regarding the concern that tourism
companies could be impacted
financially by the planned surveys, this
statement was not supported by any
information and we cannot speculate as
to any potential effects to tourism
companies as a result of L–DEO’s
survey. NMFS also does not have any
authority under the MMPA to restrict
activities based on potential impacts to
tourism, as we do not authorize the
activity itself, as described above.
Comment 15: A member of the general
public expressed concern that the
abundances for marine mammals
provided in Table 2 in the Notice of the
Proposed IHA (82 FR 45116; September
27, 2017) do not reflect abundance
estimates for those marine mammals
specifically around New Zealand
because they incorporate population
estimates from the entire Southern
Hemisphere. The comment asserted that
many of the marine mammal species
have unique and important
subpopulations. The commenter
specifically recommended that the
abundance estimates for southern right
whale and killer whale be revised.
NMFS Response: The commenter did
not suggest specific revisions to
abundance estimates, with the
exception of southern right whale and
killer whale. With respect to southern
right whale and killer whale the
commenter did not provide specific
information to support revisions to our
abundance estimates for those species.
For southern right whales, the
commenter referenced an estimated
abundance of 200. The source for this
estimate was the Web site of a New
Zealand based non-governmental
organization; however, this Web site
does not cite any literature to support
this estimate, therefore we have no way
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to verify the accuracy of this figure or
revise our abundance estimate based on
it. For killer whale abundance, the
commenter referenced an estimated
abundance of 150–200 individuals. The
source for this estimate is a NZDOC
Web site; however, this Web site does
not cite any literature to support this
estimate, therefore we have no way to
verify the accuracy of this figure or
revise our abundance estimate based on
it. The commenter did not provide any
specific recommendations regarding
revisions to abundance estimates for any
other species. The commenter refers to
marine mammals abundances described
in Baker et al. (2016); however, that
document does not provide abundance
estimates for specific marine mammal
species.
With regard to the abundance
estimates for the other species in Table
2, we made our findings about the
applicable management units and
abundance estimates for those species
based on the best available information.
Comment 16: A member of the general
public expressed concerns with and
offered suggestions about some of the
mitigation measures. Specific concerns
or suggestions raised by the commenter
were related to: Mitigation measures for
surveys during nighttime and low
visibility; the number and location of
PSOs relative to the survey vessel;
verification of sound propagation
modeling; size of exclusion zones; use
of power downs; mitigation for the
multibeam echosounder (MBES) and
sub-bottom profiler (SBP); and
shutdown requirements for Hector’s
dolphins.
NMFS Response: The commenter
expressed concern that mitigation
measures for surveys during nighttime
and low visibility conditions were
limited to use of PAM. However, the
IHA also requires that L–DEO must
provide a night-vision device suited for
the marine environment for use during
nighttime ramp-up pre-clearance, which
must include automatic brightness and
gain control, bright light protection,
infrared illumination, and optics suited
for low-light situations. We have
determined that the mitigation measures
specific to nighttime and low visibility
conditions ensure the least practicable
impact on species potentially affected.
The commenter expressed concern
that the number of required PSOs is not
sufficient, and suggested observers be
deployed on other vessels in addition to
the Langseth. However, we believe that
mitigation and monitoring measures
required in the IHA can be adequately
performed by the number of PSOs
required in the IHA, and that this has
been demonstrated through numerous
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monitoring reports submitted for past
IHAs for similar activities (i.e., marine
geophysical surveys conducted on the
Langseth) which have used the same
number of PSOs and the same PSO
staffing configurations as that required
in this IHA. We believe the number and
location of PSOs required in the IHA
ensure the least practicable impact on
species potentially affected.
The commenter expressed concern
that sound propagation should be
verified in the field to ensure accuracy
of the sound propagation models. The
commenter expressed that this would be
of particular concern in regards to the
South Island Hector’s dolphin
subpopulation that has site fidelity to Te
Waewae Bay. As described above,
NMFS believes that L–DEO’s current
modeling approach represents the best
available information for NMFS to reach
determinations for this IHA. We refer
the reader to the response to Comment
1, above, for a more detailed discussion
of L–DEO’s acoustic modeling
methodology. In addition, as described
above, results of acoustic modeling
represent just one component of the
analysis during the MMPA
authorization process, as NMFS also
takes into consideration other factors
associated with the activity and, as
described herein, our determination of
the appropriate distance for mitigation
zones is not based on acoustic
modeling. With respect to the use of
sound source verification to verify the
distances to isopleths that coincide with
harassment thresholds for Hector’s
dolphins, we have incorporated a
requirement in the IHA that the array
must be shut down upon visual or
acoustic detection of Hector’s dolphins
at any distance, as described below.
The commenter expressed concern
about the 500 m exclusion zone and
recommended that the exclusion zone
should be extended to between 1–1.5
km for all species of marine mammals
detected visually and/or acoustically,
and referred to more conservative zones
required by the Code for some marine
mammals. As described in the Federal
Register Notice of the Proposed IHA (82
FR 45116; September 27, 2017), our use
of 500 m as the EZ is based on a
reasonable combination of factors. This
zone is expected to contain all potential
auditory injury for all marine mammals
(high-frequency, mid-frequency and
low-frequency cetacean functional
hearing groups and otariid and phocid
pinnipeds) as assessed against peak
pressure thresholds (NMFS, 2016)
(Tables 7, 8, 9). It is also expected to
contain all potential auditory injury for
high-frequency and mid-frequency
cetaceans as well as otariid and phocid
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pinnipeds as assessed against SELcum
thresholds (NMFS, 2016) (Tables 7, 8,
9). Additionally, the 500 m EZ is
expected to minimize the likelihood
that marine mammals will be exposed to
levels likely to result in more severe
behavioral responses. It has also proven
to be practicable through past
implementation in seismic surveys
conducted for the oil and gas industry.
A practicable criterion such as the
proposed 500 m EZ 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. With
respect to the Code, as described above,
NMFS does not have the statutory
authority to require L–DEO to abide by
the requirements of the Code outside a
finding that the Code represents
mitigation necessary to effect the least
practicable impact on the affected
marine mammal species or stocks,
which is not the case here. However, we
encourage L–DEO to comply with the
provisions of the Code to the extent
possible.
The commenter expressed concern
that the use of the single 40 in3 airgun
during power downs adds more sound
to the marine environment, though this
comment appears to be based on the
mistaken impression that the single
airgun may be used ‘‘continuously.’’ We
note that the use of the single 40 in3
airgun during power downs is, in fact,
permitted for no more than 30 minutes
at any time (as described in greater
detail in the Mitigation section below).
The comment did not cite any
substantive information regarding
power downs or make any
recommendations regarding power
downs, therefore we do not further
revise the requirements specific to
power downs in response to this
comment.
The commenter expressed concern
with the use of the MBES and SBP,
citing a report on a mass stranding of
melon-headed whales on the
Madagascar coast in 2008 that was
attributed to use of a MBES (Southall et
al., 2013). The commenter also
requested that NMFS require that the
MBES be shut down in instances when
mitigation measures require shutdown
of the airgun array.
A Kongsberg EM 122 MBES would be
operated continuously during the
proposed surveys, but not during transit
to and from the survey areas. Due to the
lower source level of the MBES relative
to the Langseth’s airgun array, sounds
from the MBES are expected to be
effectively subsumed by the sounds
from the airgun array when both sources
are operational. Thus, NMFS has
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determined that any marine mammal
potentially exposed to sounds from the
MBES would already have been exposed
to sounds from the airgun array, which
are expected to propagate further in the
water, when both sources are
operational. During periods when the
airguns are inactive and the MBES is
operational, NMFS has determined that,
given the movement and speed of the
vessel and the intermittent and narrow
downward-directed nature of the
sounds emitted by the MBES (each ping
emitted by the MBES consists of eight
(in water >1,000 m deep) or four (<1,000
m) successive fan-shaped transmissions,
each ensonifying a sector that extends 1°
fore-aft), the MBES would result in no
more than one or two brief ping
exposures to any individual marine
mammal, if any exposure were to occur.
Regarding the 2008 mass stranding of
melon-headed whales in Madagascar, it
should be noted that the report to which
the commenter refers states that while
the MBES was determined as the most
likely cause of the stranding event, there
was no unequivocal and easily
identifiable single cause of the event,
such as those that have been implicated
in previous marine mammal mortalities
(e.g., entanglement, vessel strike,
identified disease) or mass stranding
events (e.g., weather, extreme tidal
events, predator presence,
anthropogenic noise) (Southall et al.,
2013). The report also notes that the
2008 mass stranding event in
Madagascar was the first known such
marine mammal mass stranding event
closely associated with relatively highfrequency mapping sonar systems such
as MBES and that similar MBES systems
are in fact commonly used in
hydrographic surveys around the world
over large areas without such events
being previously documented (Southall
et al., 2013). The report found that in
the case of the 2008 mass stranding
event, environmental, social, or some
other confluence of factors (e.g.,
shoreward-directed surface currents and
elevated chlorophyll levels in the area
preceding the stranding) may have
meant that that particular group of
whales was oriented relative to the
directional movement of the survey
vessel (the vessel moved in a directed
manner down the shelf-break; Southall
et al., 2013, Figure 2) in such a way that
an avoidance response caused animals
to move into an unfamiliar and unsafe
out-of-habitat area (Southall et al.,
2013). NMFS is not aware of any marine
mammal stranding events that have
been documented as a result of exposure
to sounds from MBES since the
Madagascar mass stranding event in
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2008. Based on the best available
information, we do not believe the use
of the MBES aboard the Langseth will
result in marine mammal strandings.
The commenter expressed concern
that a shutdown requirement upon any
observation of Hector´s dolphins at any
distance, including upon acoustic
detection, is warranted. As described
above, based on the best available
information, NMFS agrees this measure
is warranted, and has incorporated these
requirements in the IHA. See the section
on Mitigation and the section on
Revisions to the IHA That Have
Occurred Since the Proposed IHA,
below, for details.
In summary, we have determined the
mitigation measures contained in the
IHA ensure the least practicable impact
on marine mammal species potentially
affected.
Comment 17: A member of the general
public expressed that L–DEO should
employ alternative research
technologies, including Vibroseis and
AquaVib, rather than airguns to perform
the planned marine geophysical
surveys.
NMFS Response: At this point in time,
the alternative technologies identified
by the commenter are not commercially
viable or appropriate to meet the needs
of the planned surveys. With respect to
Vibroseis, there is no commercially
available marine vibrator system that
can be used for the planned surveys.
The AquaVib is a modified version of a
land seismic vibrator system that is
capable of being placed in very shallow
water (i.e., a few meters) and in
transition zone environments (i.e.,
marshes, etc.); however the AquaVib
would not be suitable for L–DEO’s
planned surveys. As suggested by the
commenter, NMFS has requested the
National Science Foundation to
continue to review and consider
alternative technologies to support
future marine geophysical research.
Comment 18: A member of the general
public stated that L–DEO should agree
to pay for any necropsies of marine
mammals that strand around the entire
coastline of New Zealand during and
after the survey.
NMFS Response: NMFS does not
anticipate that the survey will result in
strandings of marine mammals. We also
do not have the authority to require
applicants to fund marine mammal
necropsies. However, should any
stranded animals be observed during the
surveys, we have included reporting
measures to ensure L–DEO promptly
notifies NMFS and the NZDOC (see the
section on Reporting, below).
In addition to the comments above,
NMFS received comments from the
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MSROC and an additional comment
from the general public. The comment
letter from the MSROC affirmed that
there is significant support from the
MSROC for the IHA to be issued for the
proposed surveys and for the surveys to
be conducted. A private citizen
expressed concern that animals should
not be harmed in the process of
surveying or studying them. NMFS
considered this comment, however, it
did not contain any substantive
information regarding the potential for
the proposed surveys to harm marine
mammals.
Revisions to the IHA That Have
Occurred Since the Proposed IHA
Based on public comments and a
recalculation of the take estimates in the
proposed IHA, we have made revisions
to the IHA since we published the
notice of the proposed IHA in the
Federal Register (82 FR 45116;
September 27, 2017). Those revisions
are described below.
Revisions to the take estimates—Take
estimates in the final IHA have been
revised slightly since we published the
notice of the proposed IHA in the
Federal Register (82 FR 45116;
September 27, 2017), due to a math
error in calculating the 25 percent
correction factor for uncertainty in
density estimates applied to the overall
take estimate. This has resulted in
higher take estimates in some cases, and
lower take estimates in some cases, in
comparison to the take estimates
described in the notice of the proposed
IHA. Revised take estimates are shown
in Tables 10, 11, 12 and 13. These
revisions have not impacted our
preliminary determinations.
Shutdown requirement upon visual
detection of an aggregation of large
whales at any distance—We have added
a mitigation measure that requires that
the airgun array be shut down upon
visual detection of an aggregation (i.e.,
six or more animals) of large whales of
any species (i.e., sperm whale or any
baleen whale) at any distance. This
measure is discussed in greater detail in
the Mitigation section, below.
Shutdown requirement upon visual
detection of South Island Hector’s
dolphins—We have added a mitigation
measure that requires that the airgun
array be shut down upon visual
detection of a Hector’s dolphin during
the South Island survey. Hector’s
dolphins have relatively small home
ranges and high site fidelity; a survey in
2002 found that the majority of Hector’s
dolphins ranged less than 60 km (Brager
et al., 2002); along-shore home range is
typically less than 50 km (Oremus et al.,
2012). There are at least three,
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genetically distinct, regional
populations of South Island Hector’s
dolphin (Dawson et al. 2004); a
genetically distinct and localized
population occurs in Te Waewae Bay
(Mackenzie and Clement, 2014)). Due to
the limited range and high site fidelity
of the population of Hector’s dolphin
that occurs in Te Waewae Bay and the
proximity of the planned South Island
2-D survey with Te Waewae Bay (see
Figure 2 in the IHA application), NMFS
has determined that shutdown of the
array upon visual detection of Hector’s
dolphins during the South Island 2-D
survey is warranted.
Shutdown requirement upon acoustic
detection of Hector’s dolphins, beaked
whales, sperm whales, or Kogia spp.—
We have added a mitigation measure
that requires that the airgun array be
shut down upon acoustic detection of
Hector’s dolphins, beaked whales,
sperm whales, or Kogia spp. (with an
exception for sperm whales only, if the
acoustic detection can be localized and
it is determined the sperm whale is
outside the 500 m EZ). The requirement
to shut down the airgun array upon
visual detection of a beaked whale or
Kogia spp. at any distance was included
in the Federal Register notice of the
proposed IHA (82 FR 45116; September
27, 2017) in recognition of the fact that
these species are behaviorally sensitive
deep divers and it is possible that
disturbance could provoke a severe
behavioral response leading to injury
(e.g., Wursig et al., 1998; Cox et al.,
2006). The requirement to shut down
the airgun array upon visual detection
of a Hector’s dolphin at any distance
was included in the Federal Register
notice of the proposed IHA (82 FR
45116; September 27, 2017), specifically
for the planned North Island surveys;
we have since added the requirement
that the array must be shut down upon
observation of a Hector’s dolphin, at any
distance, during the South Island survey
(as described above). The intent behind
the requirement to shut down upon
acoustic detection is the same as that
behind the requirement to shut down
upon visual detection. As discussed
above, shutdown upon visual detection
of sperm whales at any distance is not
required in the IHA (the reasoning for
this decision is described in further
detail in the Mitigation section, below).
However, we have determined that
meaningful measures are warranted to
minimize potential disruption of
foraging behavior in sperm whales. This
measure (i.e., shutdown upon acoustic
detection of beaked whales, sperm
whales, or Kogia spp., with an exception
for sperm whales only, if the acoustic
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detection can be localized and it is
determined the sperm whale is outside
the 500 m EZ) is discussed in greater
detail in the Mitigation section, below.
Revision to power down waiver for
certain delphinids—In the Federal
Register notice of the proposed IHA (82
FR 45116; September 27, 2017), NMFS
proposed a waiver to the requirement to
power down the array upon marine
mammals observed within or
approaching the 500 m exclusion zone
that would apply specifically to
cetaceans of the genera Tursiops,
Delphinus and Lissodelphis that
approach the vessel (e.g., bow riding).
We have revised this waiver to the
requirement to power down the array
such that it applies to all small dolphins
except spectacled porpoise and
bottlenose, hourglass, and Hector’s
dolphins. We have revised the species
for which the power down waiver
applies because we had previously
mistakenly excluded all dolphins in the
genera Lagenorhynchus from the power
down waiver, based on a concern
(which we still hold) that cetaceans
considered to be in the high frequency
functional hearing group would be more
sensitive to airgun sounds; however, as
dusky dolphins (Lagenorhynchus
obscurus) are in fact considered to be in
the mid frequency functional hearing
group, we believe the power down
waiver should apply to dusky dolphins.
Additionally, we have removed
cetaceans of the genera Tursiops (i.e.,
bottlenose dolphins) from the power
down waiver in response to concerns
expressed by the NZDOC, as bottlenose
dolphins are listed as a species of
concern in New Zealand and are
particularly susceptible to impacts from
human activities due to their coastal
nature. Therefore the power down
waiver will not apply for bottlenose
dolphins. Effectively, the species which
are included in the power down waiver
are: short-beaked common dolphin
(Delphinus delphis), dusky dolphin
(Lagenorhynchus obscurus) and
southern right whale dolphin
(Lissodelphis peronii). Finally, we
specified in the proposed IHA that the
waiver would only apply if the animals
were traveling, including approaching
the vessel. However, we have removed
that requirement from the IHA, based on
an acknowledgement that it would have
required subjective on-the-spot
decision-making on the part of PSOs,
which may have resulted in differential
implementation as informed by
individual PSOs’ experience,
background, and/or training.
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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
southwest Pacific Ocean off New
Zealand and summarizes information
related to the population, including
regulatory status under the MMPA and
ESA. The populations of marine
mammals considered in this document
do not occur within the U.S. EEZ and
are therefore not assigned to stocks and
are not assessed in NMFS’ Stock
Assessment Reports
(www.nmfs.noaa.gov/pr/sars/). As such,
information on potential biological
removal (PBR; defined by the MMPA as
the maximum number of animals, not
including natural mortalities, that may
be removed from a marine mammal
stock while allowing that stock to reach
or maintain its optimum sustainable
population) and on annual levels of
serious injury and mortality from
anthropogenic sources are not available
for these marine mammal populations.
In addition to the marine mammal
species known to occur in planned
survey areas, there are 16 species of
marine mammals with ranges that are
known to potentially occur in the waters
of the planned survey areas, but they are
categorized as ‘‘vagrant’’ under the New
Zealand Threat Classification System
(Baker et al., 2016). These species are:
The ginkgo-toothed whale (Mesoplodon
ginkgodens); pygmy beaked whale (M.
peruvianus); dwarf sperm whale (Kogia
sima); pygmy killer whale (Feresa
attenuata); melon-headed whale
(Peponocephala electra); Risso’s
dolphin (Grampus griseus); Fraser’s
dolphin (Lagenodelphis hosei),
pantropical spotted dolphin (Stenella
attenuata); striped dolphin (S.
coeruleoalba); rough-toothed dolphin
(Steno bredanensis); Antarctic fur seal
(Arctocephalus gazelle); Subantarctic
fur seal (A. tropicalis); leopard seal
(Hydrurga leptonyx); Weddell seal
(Leptonychotes weddellii); crabeater seal
(Lobodon carcinophagus); and Ross seal
(Ommatophoca rossi). Except for Risso’s
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dolphin and leopard seal, for which
there have been several sightings and
strandings reported in New Zealand
(Clement 2010; Torres 2012;
Berkenbusch et al. 2013; NZDOC 2017),
the other ‘‘vagrant’’ species listed above
are not expected to occur in the planned
survey areas and are therefore not
considered further in this document.
Marine mammal abundance estimates
presented in this document represent
56129
the total number of individuals
estimated within a particular study or
survey area. All values presented in
Table 2 are the most recent available at
the time of publication.
TABLE 2—MARINE MAMMALS THAT COULD OCCUR IN THE PLANNED SURVEY AREAS
Common name
Scientific name
ESA/MMPA
status;
strategic
(Y/N) 1
Stock
Population
abundance 2
Order Cetartiodactyla—Cetacea—Superfamily Mysticeti (baleen whales)
Family Balaenidae
Southern right whale ........................................
Eubalaena australis .........................................
N/A
E/D;Y
3 12,000
N/A
N/A
N/A
N/A
N/A
N/A
N/A
-/-; N
-/-; N
-/-; N
-/-; N
E/D;Y
E/D;Y
E/D;Y
3 42,000
N/A
-/-; N
Family Balaenopteridae (rorquals)
Humpback whale .............................................
Bryde’s whale ...................................................
Common minke whale .....................................
Antarctic minke whale ......................................
Sei whale .........................................................
Fin whale ..........................................................
Blue whale .......................................................
Megaptera novaeangliae .................................
Balaenoptera edeni .........................................
Balaenoptera acutorostrata .............................
Balaenoptera bonaerensis ...............................
Balaenoptera borealis ......................................
Balaenoptera physalus ....................................
Balaenoptera musculus ...................................
4 48,109
5 6 750,000
5 6 750,000
5 10,000
5 15,000
3 5 3,800
Family Cetotheriidae
Pygmy right whale ...........................................
Caperea marginata ..........................................
N/A
Superfamily Odontoceti (toothed whales, dolphins, and porpoises)
Family Physeteridae
Sperm whale ....................................................
Physeter macrocephalus .................................
N/A
E/D;Y
N/A
-/-; N
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
-/-;
-/-;
-/-;
-/-;
-/-;
-/-;
-/-;
-/-;
-/-;
-/-;
-/-;
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
-/-; N
-/-; N
-/-; N
-/-; N
-/-; N
-/-; N
T/D;Y
E/D;Y
-/-; N
-/-; N
-/-; N
-/-; N
N/A
-/-; N
5 30,000
Family Kogiidae
Pygmy sperm whale .........................................
Kogia breviceps ...............................................
N/A
Family Ziphiidae (beaked whales)
Cuvier’s beaked whale .....................................
Arnoux’s beaked whale ....................................
Shepherd’s beaked whale ...............................
Hector’s beaked whale ....................................
True’s beaked whale ........................................
Southern bottlenose whale ..............................
Gray’s beaked whale .......................................
Andrew’s beaked whale ...................................
Strap-toothed beaked whale ............................
Blainville’s beaked whale .................................
Spade-toothed beaked whale ..........................
Ziphius cavirostris ............................................
Berardius arnuxii ..............................................
Tasmacetus shepherdi ....................................
Mesoplodon hectori .........................................
Mesoplodon mirus ...........................................
Hyperoodon planifrons ....................................
Mesoplodon grayi ............................................
Mesoplodon bowdoini ......................................
Mesoplodon layardii .........................................
Mesoplodon densirostris ..................................
Mesoplodon traversii .......................................
N
N
N
N
N
N
N
N
N
N
N
5 7 600,000
5 7 600,000
5 7 600,000
5 7 600,000
N/A
5 7 600,000
5 7 600,000
5 7 600,000
5 7 600,000
5 7 600,000
5 7 600,000
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Family Delphinidae
Bottlenose dolphin ...........................................
Short-beaked common dolphin ........................
Dusky dolphin ..................................................
Hourglass dolphin ............................................
Southern right whale dolphin ...........................
Risso’s dolphin .................................................
South Island Hector’s dolphin ..........................
Maui dolphin .....................................................
False killer whale .............................................
Killer whale .......................................................
Long-finned pilot whale ....................................
Short-finned pilot whale ...................................
Tursiops truncatus ...........................................
Delphinus delphis ............................................
Lagenorhynchus obscurus ..............................
Lagenorhynchus cruciger ................................
Lissodelphis peronii .........................................
Grampus griseus .............................................
Cephalorhynchus hectori hectori .....................
Cephalorhynchus hectori maui ........................
Pseudorca crassidens .....................................
Orcinus orca ....................................................
Globicephala melas .........................................
Globicephala macrorhynchus ..........................
N/A
N/A
8 12,000–20,000
5 150,000
N/A
N/A
9 14,849
10 63
N/A
5 80,000
5 200,000
N/A
Family Phocoenidae (porpoises)
Spectacled porpoise ........................................
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Phocoena dioptrica ..........................................
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TABLE 2—MARINE MAMMALS THAT COULD OCCUR IN THE PLANNED SURVEY AREAS—Continued
Common name
Scientific name
ESA/MMPA
status;
strategic
(Y/N) 1
Stock
Population
abundance 2
Order Carnivora—Superfamily Pinnipedia
Family Otariidae (eared seals and sea lions)
New Zealand fur seal .......................................
New Zealand sea lion ......................................
N/A
N/A
-/-; N
-/-; N
8 200,000
N/A
N/A
Arctocephalus forsteri ......................................
Phocarctos hookeri ..........................................
-/-; N
-/-; N
8 222,000
11 9,880
Family Phocidae (earless seals)
Leopard seal ....................................................
Southern elephant seal ....................................
Hydrurga leptonyx ...........................................
Mirounga leonina .............................................
8 607,000
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N/A = Not available or not assessed.
1 Endangered Species Act (ESA) status: Endangered (E), Threatened (T)/MMPA status: Depleted (D). A dash (-) indicates that the species is
not listed under the ESA or designated as depleted under the MMPA. Under the MMPA, a strategic stock is one for which the level of direct
human-caused mortality exceeds PBR or which is determined to be declining and likely to be listed under the ESA within the foreseeable future.
Any species or stock listed under the ESA is automatically designated under the MMPA as depleted and as a strategic stock.
2 Abundance for the Southern Hemisphere or Antarctic unless otherwise noted.
3 IWC (2016).
4 IWC (1981).
5 Boyd (2002).
6 Dwarf and Antarctic minke whales combined.
7 All Antarctic beaked whales combined.
8 Estimate for New Zealand; NZDOC 2017.
9 Estimate for New Zealand; MacKenzie and Clement 2016.
10 Estimate for New Zealand; Baker et al. (2016).
11 Geschke and Chilvers (2009).
All species that could potentially
occur in the planned survey areas are
included in table 2. However, of the
species described in Table 2, the
temporal and/or spatial occurrence of
one subspecies, the Maui dolphin (also
known as the North Island Hector’s
dolphin), is such that take is not
expected to occur as a result of the
surveys. The Maui dolphin is one of two
subspecies of Hector’s dolphin (the
other being the South Island Hector’s
dolphin), both of which are endemic to
New Zealand. The Maui dolphin has
been demonstrated to be genetically
distinct from the South Island
subspecies of Hector’s dolphin based on
studies of mitochondrial and nuclear
DNA (Pichler et al. 1998). It is currently
considered one of the rarest dolphins in
the world with a population size
estimated at just 55–63 individuals
(Hamner et al. 2014; Baker et al. 2016).
Historically, Hector’s dolphins are
thought to have ranged along almost the
entire coastlines of both the North and
South Islands of New Zealand, though
their present range is substantially
smaller (Pichler 2002). The range of the
Maui dolphin in particular has
undergone a marked reduction (Dawson
et al. 2001; Slooten et al. 2005), with the
subspecies now restricted to the
northwest coast of the North Island,
between Maunganui Bluff in the north
and Whanganui in the south (Currey et
al. 2012). Occasional sightings and
strandings have also been reported from
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areas further south along the west coast
as well as possible sightings in other
areas such as Hawke’s Bay on the east
coast of North Island (Baker 1978,
Russell 1999, Ferreira and Roberts 2003,
Slooten et al. 2005, DuFresne 2010,
Berkenbusch et al. 2013; Torres et al.
´
˜
2013; Patino-Perez 2015; NZDOC 2017)
though it is unclear whether those
individuals may have originated from
the South Island Hector’s dolphin
populations. A 2016 NMFS Draft Status
Review Report concluded the Maui
dolphin is facing a high risk of
extinction as a result of small
population size, reduced genetic
diversity, low theoretical population
growth rates, evidence of continued
population decline, and the ongoing
threats of fisheries bycatch, disease,
mining and seismic disturbances
(Manning and Grantz 2016). Due to its
extremely low population size and the
fact that the subspecies is not expected
to occur in the planned survey areas off
the North Island, take of Maui dolphins
is not expected to occur as a result of
L–DEO’s activities. Therefore the Maui
dolphin is not discussed further beyond
the explanation provided here.
We have reviewed L–DEO’s species
descriptions, including life history
information, distribution, regional
distribution, diving behavior, and
acoustics and hearing, for accuracy and
completeness. We refer the reader to
Section 4 of L–DEO’s IHA application,
rather than reprinting the information
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here. A detailed description of the
species likely to be affected by L–DEO’s
survey, including brief introductions to
the species and relevant stocks as well
as available information regarding
population trends and threats, and
information regarding local occurrence,
were provided in the Federal Register
notice for the proposed IHA (82 FR
45116; September 27, 2017). Since that
time, we are not aware of any changes
in the status of these species and stocks;
therefore, detailed descriptions are not
provided here. Please refer to that
Federal Register notice for these
descriptions. Please also refer to NMFS’
Web site (www.nmfs.noaa.gov/pr/
species/mammals/) for generalized
species accounts.
Potential Effects of Specified Activities
on Marine Mammals and Their Habitat
The effects of underwater noise from
marine geophysical survey activities
have the potential to result in behavioral
harassment and, in a limited number of
instances, auditory injury (PTS) of
marine mammals in the vicinity of the
action area. The Federal Register notice
of proposed IHA (82 FR 45116;
September 27, 2017) included a
discussion of the effects of
anthropogenic noise on marine
mammals and their habitat, therefore
that information is not repeated here;
please refer to that Federal Register
notice for that information. No instances
of serious injury or mortality are
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expected as a result of L–DEO’s survey
activities.
Estimated Take
This section provides an estimate of
the number of incidental takes
authorized through the 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 are primarily 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., Kogia
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 mitigation and
monitoring measures are expected to
minimize the severity of such taking to
the extent practicable.
As described previously, no serious
injury or mortality is anticipated or
authorized for this activity. Below we
describe how the take is estimated.
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
authorized.
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
micropascal (mPa) (rms) for continuous
sources (e.g. vibratory pile-driving,
drilling) and above 160 dB re 1 mPa
(rms) for non-explosive impulsive (e.g.,
seismic airguns) or intermittent (e.g.,
scientific sonar) sources. L–DEO’s
activity includes the use of impulsive
seismic sources. 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 3
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,
L–DEO’s activity includes the use of
intermittent and impulsive seismic
sources.
TABLE 3—THRESHOLDS IDENTIFYING THE ONSET OF PERMANENT THRESHOLD SHIFT IN MARINE MAMMALS
PTS onset thresholds
Hearing group
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Impulsive *
Low-Frequency (LF) Cetaceans .........................................................................
Mid-Frequency (MF) Cetaceans .........................................................................
High-Frequency (HF) Cetaceans .......................................................................
Phocid Pinnipeds (PW) (Underwater) ................................................................
Otariid Pinnipeds (OW) (Underwater) ................................................................
Lpk,flat:
Lpk,flat:
Lpk,flat:
Lpk,flat:
Lpk,flat:
219
230
202
218
232
dB;
dB;
dB;
dB;
dB;
Non-impulsive
LE,LF,24h: 183 dB ........
LE,MF,24h: 185 dB ........
LE,HF,24h: 155 dB ........
LE,PW,24h: 185 dB .......
LE,OW,24h: 203 dB .......
LE,LF,24h: 199 dB.
LE,MF,24h: 198 dB.
LE,HF,24h: 173 dB.
LE,PW,24h: 201 dB.
LE,OW,24h: 219 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.
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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.
Ensonified Area
Here, we describe operational and
environmental parameters of the activity
that will feed into estimating the area
ensonified above the relevant acoustic
thresholds.
The survey entails use of a 36-airgun
array with a total discharge of 6,600 in3
at a tow depth of 9 m and an 18-airgun
array with a total discharge of 3,300 in3
at a tow depth of 7–9 m. Received sound
levels were predicted by L–DEO’s model
(Diebold et al., 2010) as a function of
distance from the 36-airgun array and
18-airgun array and for a single 40-in3
airgun which would be used during
power downs; all models used a 9 m
tow depth. This 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 constantvelocity half-space (infinite
homogeneous ocean layer, unbounded
by a seafloor). In addition, propagation
measurements of pulses from the 36airgun array at a tow depth of 6 m have
been reported in deep water
(approximately 1600 m), intermediate
water depth on the slope (approximately
600–1,100 m), and shallow water
(approximately 50 m) in the Gulf of
Mexico in 2007–2008 (Tolstoy et al.
2009; Diebold et al. 2010).
For deep and intermediate-water
cases, L–DEO determined that the field
measurements cannot be used readily to
derive zone of ensonification, as at those
sites the calibration hydrophone was
located at a roughly constant depth of
350–500 m, which may not intersect all
the SPL isopleths at their widest point
from the sea surface down to water
depths of approximately 2,000 m (See
Appendix H in NSF–USGS 2011). At
short ranges, where the direct arrivals
dominate and the effects of seafloor
interactions are minimal, the data
recorded at the deep and slope sites are
suitable for comparison with modeled
levels at the depth of the calibration
hydrophone. At longer ranges, the
comparison with the mitigation model—
constructed from the maximum SPL
through the entire water column at
varying distances from the airgun
array—is the most relevant. Please see
the IHA application for further
discussion of summarized results.
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For deep water (>1,000 m), L–DEO
used the deep-water radii obtained from
model results down to a maximum
water depth of 2000 m. The radii for
intermediate water depths (100–1,000
m) were derived from the deep-water
ones by applying a correction factor
(multiplication) of 1.5, such that
observed levels at very near offsets fall
below the corrected mitigation curve
(See Fig. 16 in Appendix H of NSF–
USGS, 2011). The shallow-water radii
were obtained by scaling the empirically
derived measurements from the Gulf of
Mexico calibration survey to account for
the differences in tow depth between
the calibration survey (6 m) and the
planned surveys (9 m). A simple scaling
factor is calculated from the ratios of the
isopleths determined by the deep-water
L–DEO model, which are essentially a
measure of the energy radiated by the
source array.
Measurements have not been reported
for the single 40-in3 airgun. L–DEO
model results are used to determine the
160-dB (rms) radius for the 40-in3
airgun at a 9 m tow depth in deep water
(See LGL 2017, Figure 6). For
intermediate-water depths, a correction
factor of 1.5 was applied to the deepwater model results. For shallow water,
a scaling of the field measurements
obtained for the 36-airgun array was
used.
L–DEO’s modeling methodology is
described in greater detail in the IHA
application (LGL 2017) and we refer the
reader to that document rather than
repeating it here. The estimated
distances to the Level B harassment
isopleth for the Langseth’s 36-airgun
array, 18-airgun array, and the single 40in3 airgun are shown in Table 4.
TABLE 4—PREDICTED RADIAL DISTANCES FROM R/V LANGSETH SEISMIC SOURCE TO ISOPLETHS CORRESPONDING TO LEVEL B HARASSMENT THRESHOLD
Source and volume
Water depth
(m)
1 airgun, 40 in3 ............
18 airguns, 3,300 in3 ...
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>1,000
100–1,000
<100
>1,000
100–1,000
Sfmt 4703
Predicted
distance to
threshold
(160 dB re
1 μPa) 1
(m)
388
582
938
3,562
5,343
TABLE 4—PREDICTED RADIAL DISTANCES FROM R/V LANGSETH SEISMIC SOURCE TO ISOPLETHS CORRESPONDING TO LEVEL B HARASSMENT THRESHOLD—Continued
Source and volume
36 airguns, 6,600 in3 ...
Water depth
(m)
<100
>1,000
100–1,000
<100
Predicted
distance to
threshold
(160 dB re
1 μPa) 1
(m)
10,607
5,629
8,444
22,102
1 Distances for depths >1,000 m are based on L–
DEO model results. Distance for depths 100–1,000
m are based on L–DEO model results with a 1.5 ×
correction factor between deep and intermediate
water depths. Distances for depths <100 m are
based on empirically derived measurements in the
Gulf of Mexico with scaling applied to account for differences in tow depth.
Predicted distances to Level A
harassment isopleths, which vary based
on marine mammal hearing groups,
were calculated based on modeling
performed by L–DEO using the
NUCLEUS software program and the
NMFS User Spreadsheet, described
below. The updated acoustic thresholds
for impulsive sounds (e.g., airguns)
contained in the Technical Guidance
were presented as dual metric acoustic
thresholds using both SELcum and peak
sound pressure metrics (NMFS 2016).
As dual metrics, NMFS considers onset
of PTS (Level A harassment) to have
occurred when either one of the two
metrics is exceeded (i.e., metric
resulting in the largest isopleth). The
SELcum metric considers both level and
duration of exposure, as well as
auditory weighting functions by marine
mammal hearing group. In recognition
of the fact that the requirement to
calculate Level A harassment ensonified
areas could be more technically
challenging to predict due to the
duration component and the use of
weighting functions in the new SELcum
thresholds, NMFS developed an
optional User Spreadsheet that includes
tools to help predict a simple isopleth
that can be used in conjunction with
marine mammal density or occurrence
to facilitate the estimation of take
numbers.
The values for SELcum and peak SPL
for the Langseth airgun array were
derived from calculating the modified
farfield signature (Table 5). The farfield
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signature is often used as a theoretical
representation of the source level. To
compute the farfield signature, the
source level is estimated at a large
distance below the array (e.g., 9 km),
and this level is back projected
mathematically to a notional distance of
1 m from the array’s geometrical center.
However, when the source is an array of
multiple airguns separated in space, the
source level from the theoretical farfield
signature is not necessarily the best
measurement of the source level that is
physically achieved at the source
(Tolstoy et al. 2009). Near the source (at
short ranges, distances <1 km), the
pulses of sound pressure from each
individual airgun in the source array do
not stack constructively, as they do for
the theoretical farfield signature. The
pulses from the different airguns spread
out in time such that the source levels
observed or modeled are the result of
the summation of pulses from a few
airguns, not the full array (Tolstoy et al.
2009). At larger distances, away from
the source array center, sound pressure
of all the airguns in the array stack
coherently, but not within one time
sample, resulting in smaller source
levels (a few dB) than the source level
derived from the farfield signature.
Because the farfield signature does not
take into account the large array effect
near the source and is calculated as a
point source, the modified farfield
signature is a more appropriate measure
of the sound source level for distributed
sound sources, such as airgun arrays.
L–DEO used the acoustic modeling
methodology as used for Level B takes
with a small grid step of 1 m in both the
inline and depth directions. The
propagation modeling takes into
account all airgun interactions at short
distances from the source, including
interactions between subarrays which
are modeled using the NUCLEUS
software to estimate the notional
signature and MATLAB software to
calculate the pressure signal at each
mesh point of a grid.
TABLE 5—MODELED SOURCE LEVELS BASED ON MODIFIED FARFIELD SIGNATURE FOR THE R/V LANGSETH 6,600 IN 3
AIRGUN ARRAY, 3,300 IN3 AIRGUN ARRAY, AND SINGLE 40 IN3 AIRGUN
Low frequency
cetaceans
(Lpk,flat: 219
dB; LE,LF,24h:
183 dB)
Mid frequency
cetaceans
(Lpk,flat: 230
dB; LE,MF,24h:
185 dB)
250.77
232.75
246.34
226.22
224.02
202.33
252.76
232.67
250.98
226.13
225.16
202.35
6,600 in3 airgun array (Peak SPLflat) ..................................
6,600 in3 airgun array (SELcum) ..........................................
3,300 in3 airgun array (Peak SPLflat) ..................................
3,300 in3 airgun array (SELcum) ..........................................
40 in3 airgun (Peak SPLflat) .................................................
40 in3 airgun (SELcum) .........................................................
In order to more realistically
incorporate the Technical Guidance’s
weighting functions over the seismic
array’s full acoustic band, unweighted
spectrum data for the Langseth’s airgun
array (modeled in 1 hertz (Hz) bands)
was used to make adjustments (dB) to
the unweighted spectrum levels, by
frequency, according to the weighting
functions for each relevant marine
mammal hearing group. These adjusted/
weighted spectrum levels were then
converted to pressures (mPa) in order to
integrate them over the entire
broadband spectrum, resulting in
broadband weighted source levels by
hearing group that could be directly
incorporated within the User
Spreadsheet (i.e., to override the
Spreadsheet’s more simple weighting
factor adjustment). Using the User
Spreadsheet’s ‘‘safe distance’’
methodology for mobile sources
(described by Sivle et al., 2014) with the
hearing group-specific weighted source
levels, and inputs assuming spherical
spreading propagation and source
velocities and shot intervals specific to
each of the three planned surveys (Table
1), potential radial distances to auditory
injury zones were then calculated for
SELcum thresholds.
Inputs to the User Spreadsheets in the
form of estimated SLs are shown in
Table 5. User Spreadsheets used by
L–DEO to estimate distances to Level A
harassment isopleths (SELcum) for the
High frequency
cetaceans
(Lpk,flat: 202
dB; LE,HF,24h:
155 dB)
249.44
232.83
243.64
226.75
224.00
203.12
Phocid
pinnipeds
(underwater)
(Lpk,flat: 218
dB; LE,HF,24h:
185 dB)
250.50
232.67
246.03
226.13
224.09
202.35
Otariid
pinnipeds
(underwater)
(Lpk,flat: 232
dB; LE,HF,24h:
203 dB)
252.72
231.07
251.92
226.89
226.64
202.61
36-airgun array, 18-airgun array, and the
single 40 in 3 airgun for the South Island
2-D survey, North Island 2-D survey,
and North Island 3-D survey are shown
in Tables 3, 4, 7, 10, 11, and 12, of the
IHA application (LGL 2017). Outputs
from the User Spreadsheets in the form
of estimated distances to Level A
harassment isopleths for the South
Island 2-D survey, North Island 2-D
survey, and North Island 3-D survey are
shown in Tables 6, 7 and 8,
respectively. As described above, NMFS
considers onset of PTS (Level A
harassment) to have occurred when
either one of the dual metrics (SELcum
and Peak SPLflat) is exceeded (i.e.,
metric resulting in the largest isopleth).
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TABLE 6—MODELED RADIAL DISTANCES (m) TO ISOPLETHS CORRESPONDING TO LEVEL A HARASSMENT THRESHOLDS
DURING NORTH ISLAND 2-D SURVEY
Low frequency
cetaceans
(Lpk,flat: 219
dB; LE,LF,24h:
183 dB)
Mid frequency
cetaceans
(Lpk,flat: 230
dB; LE,MF,24h:
185 dB)
38.8
501.3
1.8
0.4
13.8
0
0.6
0
6,600 in3 airgun array (Peak SPLflat) ..................................
6,600 in3 airgun array (SELcum) ..........................................
40 in3 airgun (Peak SPLflat) .................................................
40 in3 airgun (SELcum) .........................................................
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High frequency
cetaceans
(Lpk,flat: 202
dB; LE,HF,24h:
155 dB)
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229.2
1.2
12.6
0
27NON2
Phocid
pinnipeds
(underwater)
(Lpk,flat: 218
dB; LE,HF,24h:
185 dB)
42.2
13.2
2.0
0
Otariid
pinnipeds
(underwater)
(Lpk,flat: 232
dB; LE,HF,24h:
203 dB)
10.9
0
0.5
0
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TABLE 7—MODELED RADIAL DISTANCES (m) TO ISOPLETHS CORRESPONDING TO LEVEL A HARASSMENT THRESHOLDS
DURING NORTH ISLAND 3-D SURVEY
Low frequency
cetaceans
(Lpk,flat: 219
dB; LE,LF,24h:
183 dB)
Mid frequency
cetaceans
(Lpk,flat: 230
dB; LE,MF,24h:
185 dB)
23.3
73.1
1.8
0.4
High frequency
cetaceans
(Lpk,flat: 202
dB; LE,HF,24h:
155 dB)
11.2
0
0.6
0
3,300 in3 airgun array (Peak SPLflat) ..................................
3,300 in3 airgun array (SELcum) ..........................................
40 in3 airgun (Peak SPLflat) .................................................
40 in3 airgun (SELcum) .........................................................
Phocid
Pinnipeds (Underwater)
(Lpk,flat: 218
dB; LE,HF,24h:
185 dB)
Otariid
Pinnipeds (Underwater)
(Lpk,flat: 232
dB; LE,HF,24h:
203 dB)
25.2
2.8
2.0
0
9.9
0
0.5
0
119.0
0.3
12.6
0
TABLE 8—MODELED RADIAL DISTANCES (m) TO ISOPLETHS CORRESPONDING TO LEVEL A HARASSMENT THRESHOLDS
DURING SOUTH ISLAND 2-D SURVEY
Low frequency
cetaceans
(Lpk,flat: 219
dB; LE,LF,24h:
183 dB)
Mid frequency
cetaceans
(Lpk,flat: 230
dB; LE,MF,24h:
185 dB)
38.8
376.0
1.8
0.3
13.8
0
0.6
0
6,600 in3 airgun array (Peak SPLflat) ..................................
6,600 in3 airgun array (SELcum) ..........................................
40 in3 airgun (Peak SPLflat) .................................................
40 in3 airgun (SELcum) .........................................................
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 3-D modeling methods are
not available, and NMFS continues to
develop ways to quantitatively refine
these tools and will qualitatively
address the output where appropriate.
For mobile sources, such as the planned
seismic surveys, 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.
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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).
No systematic aircraft- or ship-based
surveys have been conducted for marine
mammals in offshore waters of the
South Pacific Ocean off New Zealand
that can be used to estimate species
densities that we are aware of, with the
exception of Hector’s dolphin surveys
that have occurred off the South Island.
Densities for Hector’s dolphins off the
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South Island were estimated using
averaged estimated summer densities
from the most southern stratum of an
East Coast South Island survey (Otago)
and a West Coast South Island survey
(Milford Sound), both in three offshore
strata categories (0–4 nautical miles
(nm), 4–12 nm, and 12–20 nm;
MacKenzie and Clement 2014, 2016).
The estimated density for Hector’s
dolphins for the South Island 2-D
survey was based on the proportion of
that survey occurring in each offshore
stratum.
For cetacean species other than
Hector’s dolphin, densities were derived
from data available for the Southern
Ocean (Butterworth et al. 1994;
Kasamatsu and Joyce 1995) (See Table
17 in the IHA application). Butterworth
et al. (1994) provided comparable data
for sei, fin, blue, and sperm whales
extrapolated to latitudes 30–40° S., 40–
50° S., and 50–60° S. based on Japanese
scouting vessel data from 1965/66–
1977/78 and 1978/79–1987/88.
Densities were calculated for these
species based on abundances and
surface areas provided in Butterworth et
al. (1994) using the mean density for the
more recent surveys (1978/79–1987/88)
and the 30–40° S. and 40–50° S. strata,
because the planned survey areas are
between ∼37° S. and 50° S. Densities
were corrected for mean trackline
detection probability, g(0) availability
bias, using mean g(0) values provided
for these species during NMFS
Southwest Fisheries Science Center
PO 00000
High frequency
cetaceans
(Lpk,flat: 202
dB; LE,HF,24h:
155 dB)
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Phocid
Pinnipeds (Underwater)
(Lpk,flat: 218
dB; LE,HF,24h:
185 dB)
Otariid
Pinnipeds (Underwater)
(Lpk,flat: 232
dB; LE, HF,24h:
203 dB)
42.2
9.9
2.0
0
10.9
0
0.5
0
229.2
0.9
12.6
0
ship-based surveys between 1991–2014
(Barlow 2016). Data for the humpback
whale was also presented in
Butterworth et al. (1994), but, based on
the best available information, it was
determined that the density values
presented for humpback whales in
Butterworth et al. (1994) were likely
lower than would be expected in the
planned survey areas, thus the density
for humpback whales was ultimately
calculated in the same way as for the
baleen whales for which density data
was unavailable. Kasamatsu and Joyce
(1995) provided data for beaked whales,
killer whales, long-finned pilot whales,
and hourglass dolphins, based on
surveys conducted as part of the
International Whaling Commission/
International Decade of Cetacean
Research—Southern Hemisphere Minke
Whale Assessment, started in 1978/79,
and the Japanese sightings survey
program started in 1976/77. Densities
for these species were calculated based
on abundances and surface areas
provided in Kasamatsu and Joyce (1995)
for Antarctic Areas V EMN and VI WM,
which represent the two areas reported
in Kasamatsu and Joyce (1995) that are
nearest to the planned South Island
survey area. Densities were corrected for
availability bias using mean g(0) values
provided by Kasamatsu and Joyce (1995)
for beaked whales, killer whales, and
long-fined pilot whales, and provided
by Barlow (2016) for the Hourglass
dolphin using the mean g(0) calculated
for unidentified dolphins during NMFS
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Southwest Fisheries Science Center
ship-based surveys between 1991–2014.
For the remaining cetacean species,
the relative abundances of individual
species expected to occur in the survey
areas were estimated within species
groups. The relative abundances of
these species were estimated based on
several factors, including information
on marine mammal observations from
areas near the planned survey areas
(e.g., monitoring reports from previous
IHAs (NMFS, 2015); datasets of
opportunistic sightings (Torres et al.,
2014); and analyses of observer data
from other marine geophysical surveys
conducted in New Zealand waters (Blue
Planet, 2016)), information on
latitudinal ranges and group sizes of
marine mammals in New Zealand
waters (e.g., Jefferson et al., 2015;
NABIS, 2017; Perrin et al., 2009), and
other information on marine mammals
in and near the planned survey areas
(e.g., data on marine mammal bycatch in
New Zealand fisheries (Berkenbush et
al., 2013), data on marine mammal
strandings (New Zealand Marine
Mammal Strandings and Sightings
Database); and input from subject matter
experts (pers. comm., E. Slooten, Univ.
of Otago, to H. Goldstein, NMFS, April
11, 2015)).
For each species group (i.e.,
mysticetes), densities of species for
which data were available were
averaged to get a mean density for the
group (e.g., densities of fin, sei, and blue
whale were averaged to get a mean
density for mysticetes). Relative
abundances of those species were then
averaged to get mean relative
abundances (e.g., relative abundance of
fin, sei, and blue whale were averaged
to get a mean relative abundance for
mysticetes). For the species for which
density data was unavailable, their
relative abundance score was multiplied
by the mean density of their respective
species group (i.e., relative abundance
of minke whale was multiplied by mean
density for mysticetes). The product was
then divided by the mean relative
abundance of the species group to come
up with a density estimate. The fin, sei,
and blue whale densities calculated
from Butterworth et al. (1994) were
proportionally averaged and used to
estimate the densities of the remaining
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mysticetes. The sperm whale density
calculated from Butterworth et al.
(1994) was used to estimate the density
of the other Physeteridae species, the
pygmy sperm whale. The hourglass
dolphin, killer whale, and long-finned
pilot whale densities calculated from
Kasamatsu and Joyce (1995) were
proportionally averaged and used to
estimate the densities of the other
Delphinidae for which density data was
not available. For beaked whales, the
beaked whale density calculated from
Kasamatsu and Joyce (1995) was
proportionally allocated according to
each beaked whale species’ estimated
relative abundance value.
We are not aware of any information
regarding at-sea densities of pinnipeds
off New Zealand. As such, a surrogate
species (northern fur seal) was used to
estimate offshore pinniped densities for
the planned surveys. The at-sea density
of northern fur seals reported in Bonnell
et al. (1992), based on systematic aerial
surveys conducted in 1989–1990 in
offshore areas off the west coast of the
U.S., was used to estimate the numbers
of pinnipeds that might be present off
New Zealand. The northern fur seal
density reported in Bonnell et al. (1992)
was used as the New Zealand fur seal
density. Densities for the other three
pinniped species expected to occur in
the planned survey areas were
proportionally allocated relative to the
value of the density of the northern fur
seal, in accordance to the estimated
relative abundance value of each of the
other pinniped species.
NMFS acknowledges there is some
uncertainty related to the estimated
density data and the assumptions used
in their calculations. Given the lack of
available data on marine mammal
density in the planned survey areas, the
approach used is based on the best
available data. In recognition of the
uncertainties in the density data, we
have included an additional 25 percent
contingency in take estimates to account
for the fact that density estimates used
to estimate take may be underestimates
of actual densities of marine mammals
in the survey area. However, there is no
information to suggest that the density
estimates used are in fact
underestimates.
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Take Calculation and Estimation
Here we describe how the information
provided above is brought together to
produce a quantitative take estimate. In
order to estimate the number of marine
mammals predicted to be exposed to
sound levels that would result in Level
A harassment or Level B harassment,
radial distances from the airgun array to
predicted isopleths corresponding to the
Level A harassment and Level B
harassment thresholds are calculated, as
described above. Those radial distances
are then used to calculate the area(s)
around the airgun array predicted to be
ensonified to sound levels that exceed
the Level A harassment and Level B
harassment thresholds. The area
estimated to be ensonified in a single
day of the survey is then calculated
(Table 9), based on the areas predicted
to be ensonified around the array and
the estimated trackline distance traveled
per day. This number is then multiplied
by the number of survey days (i.e., 35
days for the North Island 2-D survey, 33
days for the North Island 3-D survey,
and 22 days for the South Island 2-D
survey). The product is then multiplied
by 1.25 to account for an additional 25
percent contingency for potential
additional seismic operations
(associated with turns, airgun testing,
and repeat coverage of any areas where
initial data quality is sub-standard, as
proposed by L–DEO). This results in an
estimate of the total areas (km2)
expected to be ensonified to the Level
A harassment and Level B harassment
thresholds. For purposes of Level B take
calculations, areas estimated to be
ensonified to Level A harassment
thresholds are subtracted from total
areas estimated to be ensonified to Level
B harassment thresholds in order to
avoid double counting the animals
taken (i.e., if an animal is taken by Level
A harassment, it is not also counted as
taken by Level B harassment). The
marine mammals predicted to occur
within these respective areas, based on
estimated densities, are assumed to be
incidentally taken. The take estimates
were then multiplied by an additional
25 percent contingency in
acknowledgement of uncertainties in
available density estimates, as described
above.
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TABLE 9—AREAS (km 2) ESTIMATED TO BE ENSONIFIED TO LEVEL A AND LEVEL B HARASSMENT THRESHOLDS PER DAY
FOR THREE PLANNED SEISMIC SURVEYS OFF NEW ZEALAND
Survey
All marine
mammals
North Island 2-D Survey ..........................
North Island 3-D Survey ..........................
South Island 2-D Survey ..........................
1 Level
Level A harassment threshold 1
Level B
harassment
threshold
Low frequency
cetaceans
Mid frequency
cetaceans
144.5
29.1
111.1
High
frequency
cetaceans
3.9
4.5
4.1
1,931.3
1,067.3
1,913.4
Otariid
pinnipeds
65.8
47.5
86.3
3.1
3.9
3.2
Phocid
pinnipeds
12.0
10.0
12.4
A ensonified areas are estimated based on the greater of the distances calculated to Level A isopleths using dual criteria (SELcum and
peakSPL).
Note: Estimated areas shown for single day do not include additional 50 percent contingency.
Factors including water depth, array
configuration, and proportion of each
survey occurring within territorial seas
(versus within the EEZ) were also
accounted for in estimates of ensonified
areas. This was accomplished by
selecting a track line for a single day (for
each of the three planned surveys) that
were representative of the entire
planned survey(s) and using that
representative track line to calculate
daily ensonified areas. Daily track line
distance was selected depending on
array configuration (i.e., 160 km per day
for the planned 2-D surveys, 200 km per
day for the planned 3-D survey).
Representative daily track lines were
chosen to reflect the proportion of water
depths (i.e., less than 100 m, 100–1,000
m, and greater than 1,000 m) expected
to occur for that entire survey (Table 4)
as distances to isopleths corresponding
to harassment vary depending on water
depth (Table 4), and water depths vary
considerably within the planned survey
areas (Table 1). Representative track
lines were also selected to reflect the
amount of effort in the New Zealand
territorial sea (versus within the New
Zealand EEZ), for each of the three
surveys, as L–DEO is not subject to the
requirements of the MMPA within the
New Zealand territorial sea. For
example, for the North Island 2-D
survey approximately nine percent of
survey effort would occur in the New
Zealand territorial sea (Table 1). Thus,
representative track lines that were
chosen also had approximately 9
percent of survey effort in territorial
seas; the resultant ensonified areas
within territorial seas were excluded
from take calculations.
Estimated takes for all marine
mammal species are shown in Tables
10, 11, 12 and 13. As described above,
we authorize the incidental takes that
are expected to occur as a result of the
planned surveys within the New
Zealand EEZ but outside of the New
Zealand territorial sea.
TABLE 10—NUMBERS OF POTENTIAL INCIDENTAL TAKE OF MARINE MAMMALS AUTHORIZED DURING L–DEO’S NORTH
ISLAND 2-D SEISMIC SURVEY OFF NEW ZEALAND
Density
(#/1,000 km2)
ethrower on DSK3G9T082PROD with NOTICES
Species
Southern right whale ........................................................................................
Pygmy right whale ...........................................................................................
Humpback whale .............................................................................................
Bryde’s whale ..................................................................................................
Common minke whale .....................................................................................
Antarctic minke whale ......................................................................................
Sei whale .........................................................................................................
Fin whale .........................................................................................................
Blue whale .......................................................................................................
Sperm whale ....................................................................................................
Cuvier’s beaked whale ....................................................................................
Arnoux’s beaked whale ...................................................................................
Southern bottlenose whale ..............................................................................
Shepard’s beaked whale .................................................................................
Hector’s beaked whale ....................................................................................
True’s beaked whale .......................................................................................
Gray’s beaked whale .......................................................................................
Andrew’s beaked whale ...................................................................................
Strap-toothed whale .........................................................................................
Blainville’s beaked whale .................................................................................
Spade-toothed whale .......................................................................................
Bottlenose dolphin ...........................................................................................
Short-beaked common dolphin ........................................................................
Dusky dolphin ..................................................................................................
Southern right-whale dolphin ...........................................................................
Risso’s dolphin .................................................................................................
False killer whale .............................................................................................
Killer whale ......................................................................................................
Long-finned pilot whale ....................................................................................
Short-finned pilot whale ...................................................................................
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Level A takes
authorized 1
0.24
0.10
0.24
0.14
0.14
0.14
0.14
0.25
0.04
2.89
2.62
2.62
1.74
1.74
1.74
0.87
3.49
1.74
2.62
0.87
0.87
5.12
10.25
5.12
3.07
2.05
3.07
1.91
8.28
4.10
E:\FR\FM\27NON2.SGM
2
1
2
1
1
1
1
2
0
1
1
1
0
0
0
0
1
0
1
0
0
1
2
1
1
0
1
0
2
1
27NON2
Level B takes
authorized 1
23
9
23
14
14
14
14
24
4
305
276
276
184
184
184
92
368
184
276
92
92
540
1080
540
324
216
324
202
872
432
Total Level A
and Level B
takes
authorized 1
25
10
25
15
15
15
15
26
4
306
277
277
184
184
184
92
369
184
277
92
92
541
1082
541
325
216
325
202
874
433
56137
Federal Register / Vol. 82, No. 226 / Monday, November 27, 2017 / Notices
TABLE 10—NUMBERS OF POTENTIAL INCIDENTAL TAKE OF MARINE MAMMALS AUTHORIZED DURING L–DEO’S NORTH
ISLAND 2-D SEISMIC SURVEY OFF NEW ZEALAND—Continued
Density
(#/1,000 km2)
Species
Pygmy sperm whale ........................................................................................
Hourglass dolphin ............................................................................................
Hector’s dolphin ...............................................................................................
Spectacled porpoise ........................................................................................
New Zealand fur seal ......................................................................................
New Zealand sea lion ......................................................................................
Southern elephant seal ....................................................................................
Leopard seal ....................................................................................................
Level A takes
authorized 1
1.74
4.16
0
0
22.50
0
4.50
2.25
6
15
0
0
4
0
3
1
Level B takes
authorized 1
177
424
0
0
2373
0
472
236
Total Level A
and Level B
takes
authorized 1
183
439
0
0
2377
0
475
237
1 Includes additional 25 percent contingency for potential additional survey operations and additional 25 percent contingency to account for uncertainties in density estimates.
TABLE 11—NUMBERS OF POTENTIAL INCIDENTAL TAKE OF MARINE MAMMALS AUTHORIZED DURING L–DEO’S NORTH
ISLAND 3-D SEISMIC SURVEY OFF NEW ZEALAND
Density
(#/1,000 km2)
ethrower on DSK3G9T082PROD with NOTICES
Species
Southern right whale ........................................................................................
Pygmy right whale ...........................................................................................
Humpback whale .............................................................................................
Bryde’s whale ..................................................................................................
Common minke whale .....................................................................................
Antarctic minke whale ......................................................................................
Sei whale .........................................................................................................
Fin whale .........................................................................................................
Blue whale .......................................................................................................
Sperm whale ....................................................................................................
Cuvier’s beaked whale ....................................................................................
Arnoux’s beaked whale ...................................................................................
Southern bottlenose whale ..............................................................................
Shepard’s beaked whale .................................................................................
Hector’s beaked whale ....................................................................................
True’s beaked whale .......................................................................................
Gray’s beaked whale .......................................................................................
Andrew’s beaked whale ...................................................................................
Strap-toothed whale .........................................................................................
Blainville’s beaked whale .................................................................................
Spade-toothed whale .......................................................................................
Bottlenose dolphin ...........................................................................................
Short-beaked common dolphin ........................................................................
Dusky dolphin ..................................................................................................
Southern right-whale dolphin ...........................................................................
Risso’s dolphin .................................................................................................
False killer whale .............................................................................................
Killer whale ......................................................................................................
Long-finned pilot whale ....................................................................................
Short-finned pilot whale ...................................................................................
Pygmy sperm whale ........................................................................................
Hourglass dolphin ............................................................................................
Hector’s dolphin ...............................................................................................
Spectacled porpoise ........................................................................................
New Zealand fur seal ......................................................................................
New Zealand sea lion ......................................................................................
Southern elephant seal ....................................................................................
Leopard seal ....................................................................................................
Level A takes
authorized 1
0.24
0.10
0.24
0.14
0.14
0.14
0.14
0.25
0.04
2.89
2.62
2.62
1.74
1.74
1.74
0.87
3.49
1.74
2.62
0.87
0.87
5.12
10.25
5.12
3.07
2.05
3.07
1.91
8.28
4.10
1.74
4.16
0
0
22.50
0
4.50
2.25
0
0
0
0
0
0
0
0
0
1
1
1
0
0
0
0
1
0
1
0
0
1
2
1
1
0
1
0
2
1
4
10
0
0
5
0
2
1
Level B takes
authorized 1
13
5
13
8
8
8
8
13
2
159
143
143
96
96
96
48
191
96
143
48
48
281
562
281
168
112
168
105
454
225
91
219
0
0
1234
0
245
123
Total Level A
and Level B
takes
authorized 1
13
5
13
8
8
8
8
13
2
160
144
144
96
96
96
48
192
96
144
48
48
282
564
282
169
112
169
105
456
226
95
229
0
0
1239
0
247
124
1 Includes additional 25 percent contingency for potential additional survey operations and additional 25 percent contingency to account for uncertainties in density estimates.
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Federal Register / Vol. 82, No. 226 / Monday, November 27, 2017 / Notices
TABLE 12—NUMBERS OF POTENTIAL INCIDENTAL TAKE OF MARINE MAMMALS AUTHORIZED DURING L–DEO’S SOUTH
ISLAND 2-D SEISMIC SURVEY OFF NEW ZEALAND
Density
(#/1,000 km2)
Species
Southern right whale ........................................................................................
Pygmy right whale ...........................................................................................
Humpback whale .............................................................................................
Bryde’s whale ..................................................................................................
Common minke whale .....................................................................................
Antarctic minke whale ......................................................................................
Sei whale .........................................................................................................
Fin whale .........................................................................................................
Blue whale .......................................................................................................
Sperm whale ....................................................................................................
Cuvier’s beaked whale ....................................................................................
Arnoux’s beaked whale ...................................................................................
Southern bottlenose whale ..............................................................................
Shepard’s beaked whale .................................................................................
Hector’s beaked whale ....................................................................................
True’s beaked whale .......................................................................................
Gray’s beaked whale .......................................................................................
Andrew’s beaked whale ...................................................................................
Strap-toothed whale .........................................................................................
Blainville’s beaked whale .................................................................................
Spade-toothed whale .......................................................................................
Bottlenose dolphin ...........................................................................................
Short-beaked common dolphin ........................................................................
Dusky dolphin ..................................................................................................
Southern right-whale dolphin ...........................................................................
Risso’s dolphin .................................................................................................
False killer whale .............................................................................................
Killer whale ......................................................................................................
Long-finned pilot whale ....................................................................................
Short-finned pilot whale ...................................................................................
Pygmy sperm whale ........................................................................................
Hourglass dolphin ............................................................................................
Hector’s dolphin ...............................................................................................
Spectacled porpoise ........................................................................................
New Zealand fur seal ......................................................................................
New Zealand sea lion ......................................................................................
Southern elephant seal ....................................................................................
Leopard seal ....................................................................................................
Level A takes
authorized 1
0.24
0.10
0.24
0.14
0.14
0.14
0.14
0.25
0.04
2.89
2.62
2.62
1.74
1.74
1.74
0.87
3.49
1.74
2.62
0.87
0.87
5.12
10.25
5.12
3.07
2.05
3.07
1.91
8.28
4.10
1.74
4.16
0
0
22.50
0
4.50
2.25
1
0
1
0
1
1
1
1
0
0
0
0
0
0
0
0
0
0
0
0
0
1
1
1
0
0
1
0
1
0
5
12
0
6
2
1
2
1
Level B takes
authorized 1
15
6
12
0
9
9
9
15
2
190
172
172
114
114
114
57
229
114
172
57
57
314
314
502
188
126
188
126
543
126
109
261
2
120
1477
591
294
147
Total Level A
and Level B
takes
authorized 1
16
6
13
0
10
10
10
16
2
190
172
172
114
114
114
57
229
114
172
57
57
315
315
503
188
126
189
126
544
126
114
273
2
126
1479
592
296
148
1 Includes additional 25 percent contingency for potential additional survey operations and additional 25 percent contingency to account for uncertainties in density estimates.
TABLE 13—TOTAL NUMBERS OF POTENTIAL INCIDENTAL TAKE OF MARINE MAMMALS AUTHORIZED DURING L–DEO’S
NORTH ISLAND 3-D SURVEY, NORTH ISLAND 2-D SURVEY, AND SOUTH ISLAND 3-D SURVEYS OF THE R/V LANGSETH
OFF NEW ZEALAND
Density
(#/1,000 km2)
ethrower on DSK3G9T082PROD with NOTICES
Species
Southern right whale ............................................................
Pygmy right whale ...............................................................
Humpback whale .................................................................
Bryde’s whale .......................................................................
Common minke whale .........................................................
Antarctic minke whale ..........................................................
Sei whale .............................................................................
Fin whale ..............................................................................
Blue whale ...........................................................................
Sperm whale ........................................................................
Cuvier’s beaked whale .........................................................
Arnoux’s beaked whale ........................................................
Southern bottlenose whale ..................................................
Shepard’s beaked whale .....................................................
Hector’s beaked whale ........................................................
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Level A takes
authorized 1
0.24
0.10
0.19
0.00
0.14
0.14
0.14
0.25
0.04
2.89
2.62
2.62
1.74
1.74
1.74
Fmt 4701
Sfmt 4703
Level B takes
authorized 1
3
1
3
1
2
2
2
3
0
2
2
2
0
0
0
E:\FR\FM\27NON2.SGM
51
20
48
22
31
31
31
52
8
654
591
591
394
394
394
27NON2
Total Level A
and Level B
takes
authorized 1
54
21
51
23
33
33
33
55
8
656
593
593
394
394
394
Total authorized Level A
and Level B
takes as a
percentage of
population
0.45
N.A.
0.12
0.05
<0.01
<0.01
0.33
0.37
0.21
2.19
0.10
0.10
0.07
0.07
0.07
56139
Federal Register / Vol. 82, No. 226 / Monday, November 27, 2017 / Notices
TABLE 13—TOTAL NUMBERS OF POTENTIAL INCIDENTAL TAKE OF MARINE MAMMALS AUTHORIZED DURING L–DEO’S
NORTH ISLAND 3-D SURVEY, NORTH ISLAND 2-D SURVEY, AND SOUTH ISLAND 3-D SURVEYS OF THE R/V LANGSETH
OFF NEW ZEALAND—Continued
Density
(#/1,000 km2)
Species
True’s beaked whale ............................................................
Gray’s beaked whale ...........................................................
Andrew’s beaked whale .......................................................
Strap-toothed whale .............................................................
Blainville’s beaked whale .....................................................
Spade-toothed whale ...........................................................
Bottlenose dolphin ...............................................................
Short-beaked common dolphin ............................................
Dusky dolphin ......................................................................
Southern right-whale dolphin ...............................................
Risso’s dolphin .....................................................................
False killer whale .................................................................
Killer whale ...........................................................................
Long-finned pilot whale ........................................................
Short-finned pilot whale .......................................................
Pygmy sperm whale ............................................................
Hourglass dolphin ................................................................
Hector’s dolphin ...................................................................
Spectacled porpoise ............................................................
New Zealand fur seal ...........................................................
New Zealand sea lion ..........................................................
Southern elephant seal ........................................................
Leopard seal ........................................................................
Level A takes
authorized 1
0.87
3.49
1.74
2.62
0.87
0.87
4.78
4.78
7.65
2.87
1.91
2.87
1.91
8.28
1.91
1.74
4.16
0.04
1.91
22.50
9.00
4.50
2.25
Level B takes
authorized 1
0
2
0
2
0
0
3
5
3
2
0
3
0
5
2
15
37
0
6
11
1
7
3
197
788
394
591
197
197
1135
1956
1323
680
454
680
433
1869
783
377
904
2
120
5084
591
1011
506
Total Level A
and Level B
takes
authorized 1
197
790
394
593
197
197
1138
1961
1326
682
454
683
433
1874
785
392
941
2
126
5095
592
1018
509
Total authorized Level A
and Level B
takes as a
percentage of
population
N.A.
0.13
0.07
0.10
0.03
0.03
N.A.
N.A.
11.05
N.A.
N.A.
N.A.
0.54
0.94
N.A.
N.A.
0.63
0.01
N.A.
2.55
5.99
0.17
0.23
ethrower on DSK3G9T082PROD with NOTICES
1 Includes additional 25 percent contingency for potential additional survey operations and additional 25 percent contingency to account for uncertainties in density estimates.
As described above, the take estimates
shown in Tables 10, 11, 12 and 13 have
been revised slightly since we published
the notice of the proposed IHA in the
Federal Register (82 FR 45116;
September 27, 2017). Revised take
estimates are higher in some cases, and
lower in some cases, in comparison to
the take estimates described in the
notice of the proposed IHA. These
revisions have not affected our
preliminary determinations.
It should be noted that the take
numbers shown in Tables 10, 11, 12 and
13 are expected to be conservative for
several reasons. First, in the calculations
of estimated take, 50 percent has been
added in the form of operational survey
days (equivalent to adding 50 percent to
the 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 substandard, and in recognition of the
uncertainties in the density estimates
used to estimate take as described
above. Additionally, marine mammals
would be expected to move away from
a loud sound source that represents an
aversive stimulus, such as an airgun
array, potentially reducing the number
of Level A takes. However, the extent to
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which marine mammals would move
away from the sound source is difficult
to quantify and is therefore not
accounted for in the take estimates
shown in 11, 12, 13 and 14.
For some marine mammal species, we
authorize a different number of
incidental takes than the number of
incidental takes requested by L–DEO
(see Tables 18, 19 and 20 in the IHA
application for requested take numbers).
For instance, for several species, L–DEO
increased the take request from the
calculated take number to 1 percent of
the estimated population size. We do
not believe it is likely that 1 percent of
the estimated population size of those
species will be taken by L–DEO’s
planned surveys, therefore we do not
authorize the take numbers requested by
L–DEO in their IHA application (LGL,
2017). However, in recognition of the
uncertainties in the density estimates
used to estimate take as described
above, we believe it is reasonable to
assume that actual takes may exceed
numbers of takes calculated based on
available density estimates; therefore,
we have increased take estimates for all
marine mammal species by an
additional 25 percent, to account for the
fact that density estimates used to
estimate take may be underestimates of
PO 00000
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actual densities of marine mammals in
the survey area. Additionally, L–DEO
requested authorization for 10 takes of
Hector’s dolphins during the North
Island 2-D survey (LGL, 2017). However,
we do not authorize any takes of
Hector’s dolphins or Maui dolphins
during North Island surveys. We believe
the likelihood of the planned North
Island 2-D survey encountering a
Hector’s dolphin or Maui dolphin is so
low as to be discountable. As described
above, the North Island subpopulation
of Hector’s dolphin (aka Maui dolphin)
is very unlikely to be encountered
during either planned North Island
survey due to the very low estimated
abundance of the subpopulation and
due to the geographic isolation of the
subpopulation (currently limited to the
west coast of the North Island, whereas
all planned North Island surveys would
occur on the eastern side of the island).
As such, we do not authorize any takes
of Hector’s dolphins or Maui dolphins
during L–DEO’s planned North Island
surveys.
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
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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.
L–DEO has reviewed mitigation
measures employed during seismic
research surveys authorized by NMFS
under previous incidental harassment
authorizations, as well as recommended
best practices in Richardson et al.
(1995), Pierson et al. (1998), Weir and
Dolman (2007), Nowacek et al. (2013),
Wright (2014), and Wright and
Cosentino (2015), and has incorporated
a suite of proposed mitigation measures
into their project description based on
the above sources.
To reduce the potential for
disturbance from acoustic stimuli
associated with the activities, L–DEO
proposed to implement the following
mitigation measures for marine
mammals:
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(1) Vessel-based visual mitigation
monitoring;
(2) Vessel-based passive acoustic
monitoring;
(3) Establishment of an exclusion
zone;
(4) Power down procedures;
(5) Shutdown procedures;
(6) Ramp-up procedures; and
(7) Vessel strike avoidance measures.
In addition to the mitigation measures
proposed by L–DEO, NMFS has
incorporated the following additional
measures:
(1) Shutdown upon observation of a
large whale with calf at any distance;
(2) Shutdown upon observation of a
Hector’s dolphin or Maui dolphin
(during North Island 2-D and North
Island 3-D surveys only) at any distance;
(3) Shutdown upon observation of an
aggregation (6 or more) of large whales
of any species at any distance;
(4) Shutdown upon any observation
(visual or acoustic) of a beaked whale or
Kogia spp. at any distance; and
(5) Shutdown upon acoustic detection
of a sperm whale (with certain
exceptions) at any distance.
As described above, measures (3), (4)
and (5) incorporated by NMFS above
were added to the suite of mitigation
measures after we published the notice
of the proposed IHA in the Federal
Register (82 FR 45116; September 27,
2017), in response to comments
received from the Commission.
Vessel-Based Visual Mitigation
Monitoring
Protected Species Observer (PSO)
observations will take place during all
daytime airgun operations and
nighttime start ups (if applicable) of the
airguns. Airgun operations will be
suspended when marine mammals are
observed within, or about to enter,
designated Exclusion Zones (as
described below). PSOs will also watch
for marine mammals near the vessel for
at least 30 minutes prior to the planned
start of airgun operations. PSOs will
monitor the entire extent of the modeled
Level B harassment zone (Table 3) (or,
as far as they are able to see, if they
cannot see to the extent of the estimated
Level B harassment zone). Observations
will also be made during daytime
periods when the Langseth 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.
During seismic operations, a
minimum of four visual PSOs will be
based aboard the Langseth. PSOs will be
appointed by L–DEO, with NMFS’
approval. During the majority of seismic
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operations, two PSOs will monitor for
marine mammals around the seismic
vessel. Use of two simultaneous
observers increases the effectiveness of
detecting marine mammals around the
source vessel. However, during meal
times, only one PSO may be on duty.
PSO(s) will be on duty in shifts of
duration no longer than 4 hours. Other
crew will 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 will be given
additional instruction in detecting
marine mammals and implementing
mitigation requirements. The Langseth
is a suitable platform for marine
mammal observations. When stationed
on the observation platform, PSOs will
have a good view around the entire
vessel. During daytime, the PSO(s) will
scan the area around the vessel
systematically with reticle binoculars
(e.g., 7 x 50 Fujinon), Big-eye binoculars
(25 x 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 will 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 high energy seismic survey,
with no more than eighteen months
elapsed since the conclusion of the atsea experience. One ‘‘experienced’’
visual PSO will be designated as the
lead for the entire protected species
observation team. The lead will
coordinate duty schedules and roles for
the PSO team and serve as primary
point of contact for the vessel operator.
The lead PSO will 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
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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.
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Vessel-Based Passive Acoustic
Mitigation Monitoring
Passive acoustic monitoring (PAM)
will take place to complement the visual
monitoring program and to inform
mitigation measures. 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 will serve to inform
mitigation measures and to alert visual
observers (if on duty) when vocalizing
cetaceans are detected. PAM 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. PAM will 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 will connect the tow cable
to the electronics unit on board where
the acoustic station, signal conditioning,
and processing system will be located.
The acoustic signals received by the
hydrophones are amplified, digitized,
and then processed by the software.
At least one acoustic PSO (in addition
to the four visual PSOs) will be on
board. The towed hydrophones will 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 Langseth 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 will
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.
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When a vocalization is detected, the
acoustic PSO will take necessary action
depending on the species and location
of the animal detected. If the species
and/or location of the animal(s)
warrants immediate shutdown of the
array, the acoustic PSO will contact the
vessel operator immediately to call for
a shutdown (see the section on
Mitigation, below, for scenarios that
require shutdown based on acoustic
detection), If the species and/or location
of the animal(s) does not warrant
immediate shutdown, the acoustic PSO
will contact 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 shutdown, if required.
The information regarding the marine
mammal acoustic detection will be
entered into a database.
In summary, a typical daytime cruise
will have scheduled two observers
(visual) on duty from the observation
platform, and an acoustic observer on
the passive acoustic monitoring system.
Exclusion Zone and Buffer Zone
An exclusion zone (EZ) is a defined
area within which occurrence of a
marine mammal triggers mitigation
action intended to reduce the potential
for certain outcomes, e.g., auditory
injury, disruption of critical behaviors.
The PSOs will establish a minimum EZ
with a 500 m radius for the 36 airgun
array and the 18 airgun array. The 500
m EZ will 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 will
be powered down (see Power Down
Procedures below). In addition to the
500 m EZ for the full arrays, a 100 m
exclusion zone will be established for
the single 40 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 will be shut down
entirely (see Shutdown Procedures
below). Additionally, power down of
the full arrays will last no more than 30
minutes maximum at any given time;
thus the arrays will be shut down
entirely if, after 30 minutes of the array
being powered down, a marine mammal
remains inside the 500 m EZ (with the
exception of spectacled porpoise and
bottlenose, hourglass, and Hector’s
dolphins, as described above).
In their IHA application, L–DEO
proposed to establish EZs based upon
modeled radial distances to auditory
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injury zones (e.g., power down would
occur when a marine mammal entered
or appeared likely to enter the zone(s)
within which auditory injury is
expected to occur based on modeling)
(Tables 6, 7, 8). However, we instead
require the 500 m EZ as described
above. The 500 m 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.
Additionally, a 500-m EZ is expected to
minimize the likelihood that marine
mammals will be exposed to levels
likely to result in more severe
behavioral responses. Although
significantly greater distances may be
observed from an elevated platform
under good conditions, we believe that
500 m is likely regularly attainable for
PSOs using the naked eye during typical
conditions.
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.
Use of monitoring and shutdown or
power-down measures within defined
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 definition of an exclusion zone on
the basis of cumulative sound exposure
level thresholds, which require that an
animal accumulate some level of sound
energy exposure over some period of
time (e.g., 24 hours), has questionable
relevance as a standard protocol. A PSO
aboard a mobile source will typically
have no ability to monitor an animal’s
position relative to the acoustic source
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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.
Cumulative SEL thresholds are more
relevant for purposes of modeling the
potential for auditory injury than they
are for dictating real-time mitigation,
though they can be informative
(especially in a relative sense). 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 is expected to contain all potential
auditory injury for all marine mammals
(high-frequency, mid-frequency and
low-frequency cetacean functional
hearing groups and otariid and phocid
pinnipeds) as assessed against peak
pressure thresholds (NMFS, 2016)
(Tables 6, 7, 8). It is also expected to
contain all potential auditory injury for
high-frequency and mid-frequency
cetaceans as well as otariid and phocid
pinnipeds as assessed against SELcum
thresholds (NMFS, 2016) (Tables 6, 7,
8). It has 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 the Bureau of Ocean
Energy Management (BOEM) pursuant
to the Outer Continental Shelf Lands
Act (43 U.S.C. 1331–1356)). In
summary, a practicable criterion, such
as the EZs described above, 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 will also establish and
monitor a 500 m buffer zone (i.e., 500
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m in addition to the 500 m EZ). During
operation of the airgun arrays,
occurrence of marine mammals within
the 500 m buffer zone (but outside the
500 m EZ) will be communicated to the
vessel operator to prepare for potential
power down or shutdown of the
acoustic source. The buffer zone is
discussed further under Ramp Up
Procedures below. PSOs will also
monitor the entire extent of the
estimated Level B harassment zone
(Table 3) (or, as far as they are able to
see, if they cannot see to the extent of
the estimated Level B harassment zone).
Power Down Procedures
A power down involves decreasing
the number of airguns in use such that
the smallest single element of the array
is in operation (i.e., one 40-in3 airgun),
with the result 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. The continued operation of one 40in3 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
array will 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
array will be powered down
immediately. During a power down of
the airgun array, the 40-in3 airgun will
be operated.
Following a power down, airgun
activity will not resume until the marine
mammal has cleared the 500 m EZ. The
animal will 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 and pinnipeds; 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 will be
in place for all marine mammals, with
the exception of certain 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
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of interacting with the vessel and/or
airgun array (e.g., bow riding). This
exception to the power down
requirement applies solely to specific
species of small dolphins: Short-beaked
common dolphin, dusky dolphin, and
southern right whale dolphin. If there is
uncertainty regarding identification (i.e.,
whether the observed animal(s) belongs
to the species described above), the
power down or shutdown must be
implemented. Note that bottlenose,
hourglass, and Hector’s dolphins and
spectacled porpoise are not included in
the power down/shutdown exception.
We include this small delphinoid
exception because power-down/
shutdown requirements for small
delphinoids under all circumstances
represent practicability concerns
without likely commensurate benefits
for the animals in question. Small
delphinoids are generally the most
commonly observed marine mammals
in the specific geographic region and
would typically be the only marine
mammals likely to intentionally
approach the vessel. As described
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 in the
Federal Register notice of the proposed
IHA (82 FR 45116; September 27, 2017)
for further discussion of sound metrics
and thresholds and marine mammal
hearing. Bottlenose dolphins are
excluded from the power down waiver
due to concerns from the New Zealand
Department of Conservation, while
hourglass, spectacled, and Hector’s
dolphins are excluded from the power
down waiver due to their functional
hearing range (they are classified as high
frequency cetaceans which would make
them more susceptible to harassment or
possible injury as a result of exposure to
airgun sounds).
A large body of anecdotal evidence
indicates that small delphinoids
commonly approach vessels and/or
towed arrays during active sound
production for purposes of bow riding,
with no apparent effect observed in
those delphinoids (e.g., Barkaszi et al.,
2012). The potential for increased
shutdowns resulting from such a
measure would require the Langseth to
revisit the missed track line to reacquire
data, resulting in an overall increase in
the total sound energy input to the
marine environment and an increase in
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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.
A power down could occur for no
more than 30 minutes maximum at any
given time. If, after 30 minutes of the
array being powered down, marine
mammals had not cleared the 500 m EZ
(as described above), a shutdown of the
array will be implemented (see Shut
Down Procedures, below). Power down
is only allowed in response to the
presence of marine mammals within the
designated EZ. Thus, the single 40 in3
airgun, which will be operated during
power downs, may not be operated
continuously throughout the night or
during transits from one line to another.
Shut Down Procedures
The single 40-in3 operating airgun
will be shut down if a marine mammal
is seen within or approaching the 100 m
EZ for the single 40-in3 airgun.
Shutdown will be implemented if (1) an
animal enters the 100 m EZ of the single
40-in3 airgun after a power down has
been initiated, or (2) an animal is
initially seen within the 100 m EZ of the
single 40-in3 airgun when more than
one airgun (typically the full array) is
operating. Airgun activity will not
resume until the marine mammal has
cleared the 500 m EZ. Criteria for
judging that the animal has cleared the
EZ will be as described above. A
shutdown of the array will be
implemented if, after 30 minutes of the
array being powered down, marine
mammals have not cleared the 500 m EZ
(as described above).
The shutdown requirement, like the
power down requirement, is waived for
dolphins of the following species: Shortbeaked common dolphin, dusky
dolphin and southern right whale
dolphin. If there is uncertainty
regarding identification (i.e., whether
the observed animal(s) belongs to the
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species described above), the shutdown
will be implemented.
Other Shutdown Requirements—In
addition to the shutdown requirement
described above, NMFS also requires
shutdown of the acoustic source in the
event of certain other observations
regardless of the defined exclusion
zone. While visual PSOs should focus
observational effort within the vicinity
of the acoustic source and vessel (i.e.,
approximately 1 km radius), this does
not preclude them from periodic
scanning of the remainder of the visible
area, and there is no reason to believe
that such periodic scans by professional
PSOs would hamper their ability to
maintain observation of areas closer to
the source and vessel. These
circumstances include:
• Upon observation of a large whale
(i.e., sperm whale or any baleen whale)
with calf at any distance, with ‘‘calf’’
defined as an animal less than twothirds the body size of an adult observed
to be in close association with an adult.
Groups of whales are likely to be more
susceptible to disturbance when calves
are present (e.g., Bauer et al., 1993), and
disturbance of cow-calf pairs could
potentially result in separation of
vulnerable calves from adults.
McCauley et al. (2000a) found that
groups of humpback whale females with
calves consistently avoided a single
operating airgun, while male
humpbacks were attracted to it,
concluding that cow-calf pairs are more
likely to exhibit avoidance responses to
unfamiliar sounds and that such
responses should be a focus of
management. Behavioral disturbance
has been implicated in mother-calf
separations for odontocete species as
well (Noren and Edwards, 2007; Wade
et al., 2012). Separation, if it occurred,
could be exacerbated by airgun signals
masking communication between adults
and the separated calf (Videsen et al.,
2017). Absent separation, airgun signals
can disrupt or mask vocalizations
essential to mother-calf interactions.
Reductions in the probability of calf
survival for gray whales have been
linked to airgun surveys in Russia
(Cooke et al., 2016).
• Upon acoustic detection of a sperm
whale (except in cases where the
location of an acoustically detected
sperm whale can be definitively
localized as outside the 500 m EZ).
Sperm whales are not necessarily
expected to display physical avoidance
of sound sources (e.g., Madsen et al.,
2002a; Jochens et al., 2008; Winsor et
al., 2017). Although Winsor et al. (2017)
report that distances and orientations
between tagged whales and active
airgun arrays appeared to be randomly
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56143
distributed with no evidence of
horizontal avoidance, it must be noted
that their study was to some degree
precipitated by an earlier observation of
significantly decreased sperm whale
density in the presence of airgun
surveys (Mate et al., 1994). However,
effects on vocal behavior are common
(e.g., Watkins and Schevill, 1975;
Watkins et al., 1985). The sperm whale’s
primary means of locating prey is
echolocation (Miller et al., 2004), and
multiple studies have shown that noise
can disrupt feeding behavior and/or
significantly reduce foraging success for
sperm whales at relatively low levels of
exposure (e.g., Miller et al., 2009, 2012;
Isojunno et al., 2016; Sivle et al., 2012;
Cure et al., 2016). Effects on energy
intake with no immediate
compensation, as is suggested by
disruption of foraging behavior without
corollary movements to new locations,
would be expected to result in
bioenergetics consequences to
individual whales.
We also considered requirement of
shutdown upon visual detection of
sperm whales at any distance. Here, we
assume that acoustic detections of
sperm whales would most likely be
representative of the foraging behavior
we intend to minimize disruption of,
while visual observations of sperm
whales would represent resting between
bouts of such behavior. Occurrence of
resting sperm whales at distances
beyond the exclusion zone may not
indicate a need to implement shutdown.
If the location of an acoustically
detected sperm whale can be
definitively localized by the PAM
operator as outside the 500 m EZ, then
the requirement to shutdown the array
is waived. If there is any uncertainty as
to whether or not an acoustically
detected sperm whale is within the 500
m EZ, shutdown must be implemented.
• Upon any observation (visual or
acoustic) of a beaked whale or Kogia
spp. These species are behaviorally
sensitive deep divers and it is possible
that disturbance could provoke a severe
behavioral response leading to injury
(e.g., Wursig et al., 1998; Cox et al.,
2006). Unlike the sperm whale, we
recognize that there are generally low
detection probabilities for beaked
whales and Kogia spp., meaning that
many animals of these species may go
undetected. Barlow (1999) estimates
such probabilities at 0.23 to 0.45 for
Cuvier’s and Mesoplodont beaked
whales, respectively. However, Barlow
and Gisiner (2006) predict a roughly 24–
48 percent reduction in the probability
of detecting beaked whales during
seismic mitigation monitoring efforts as
compared with typical research survey
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efforts, and Moore and Barlow (2013)
noted a decrease in g(0) for Cuvier’s
beaked whales from 0.23 at BSS 0 (calm)
to 0.024 at BSS 5. Similar detection
probabilities have been noted for Kogia
spp., though they typically travel in
smaller groups and are less vocal, thus
making detection more difficult (Barlow
and Forney, 2007). Because it is likely
that only a small proportion of beaked
whales and Kogia spp. potentially
affected by the planned surveys would
actually be detected, it is important to
avoid potential impacts when possible.
• Upon visual observation of an
aggregation (6 or more) of large whales
of any species (i.e., sperm whale or any
baleen whale) (e.g., feeding, socializing,
etc.). Under these circumstances, we
assume that the animals are engaged in
some important behavior (e.g., feeding,
socializing) that should not be
disturbed. By convention, we define an
aggregation as six or more animals.
• Upon observation (visual or
acoustic) of a Hector’s dolphin or Maui
dolphin (during North Island and South
Island surveys) at any distance. As
described above, the Maui dolphin is
considered one of the rarest dolphins in
the world with a population size
estimated at just 63 individuals (Baker
et al. 2016). It has undergone a marked
reduction in range (Dawson et al. 2001;
Slooten et al. 2005), and currently faces
a high risk of extinction (Manning and
Grantz, 2016). The shutdown
requirement for Hector’s/Maui dolphin
during North Island surveys is designed
to avoid any potential for exposure of a
Maui dolphin to seismic airgun sounds.
Maui dolphins are not expected to occur
in the planned survey areas off the
North Island based on their current
range. However, as described above,
there have been occasional sightings of
Hector’s dolphins off the east coast of
the North Island though it is unclear
whether those individuals may have
originated from the South Island
Hector’s dolphin populations (Baker
1978, Russell 1999, Ferreira and Roberts
2003, Slooten et al. 2005, DuFresne
2010, Berkenbusch et al. 2013; Torres et
´
˜
al. 2013; Patino-Perez 2015; NZDOC
2017). While we have determined the
likelihood of L–DEO’s planned North
Island surveys encountering a Hector’s
dolphin or Maui dolphin is extremely
low, we nonetheless include this
measure to further minimize the already
extremely unlikely potential for
exposure of a Maui dolphin to airgun
sounds. Also as described above,
Hector’s dolphins have relatively small
home ranges and high site fidelity and
a genetically distinct and localized
population occurs in Te Waewae Bay
(Mackenzie and Clement, 2014). Due to
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the limited range and high site fidelity
of the population of Hector’s dolphin
that occurs in Te Waewae Bay and the
proximity of the planned South Island
2-D survey with Te Waewae Bay we
have included this requirement to
protect the South Island Hector’s
dolphin. The requirement to shut down
on acoustic detection applies when the
acoustic detection can be positively
identified as originating from a Hector’s
dolphin.
• In the event of a shutdown due to
visual observation of a beaked whale,
Kogia spp., an aggregation of large
whales, or large whale with calf, rampup procedures will not be initiated until
the animal(s) that triggered the
shutdown has not been seen at any
distance for 30 minutes. In the event of
a shutdown due to visual or confirmed
acoustic detection of a Hector’s or Maui
dolphin, ramp-up procedures will not
be initiated until the Hector’s/Maui
dolphin has not been visually or
acoustically detected at any distance for
15 minutes. In the event of a shutdown
due to acoustic detection of a sperm
whale, Kogia spp., or beaked whale,
ramp-up procedures will not be
initiated until the animal(s) that
triggered the shutdown has not been
detected acoustically for 30 minutes.
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 is required after the
array is powered down or shut down
due to mitigation. 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. This
is the only scenario under which ramp
up is not required.
Ramp-up will begin by activating a
single airgun of the smallest volume in
the array and will continue in stages by
doubling the number of active elements
at the commencement of each stage,
with each stage of approximately the
same duration.
If airguns have been powered down or
shut down due to PSO detection of a
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marine mammal within or approaching
the 500 m EZ, ramp-up will not be
initiated until all marine mammals have
cleared the EZ, during the day or night.
Visual and acoustic PSOs are 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) will be
implemented as though the full array
were operational. Criteria for clearing
the EZ will be as described above.
Thirty minutes of pre-clearance
observation of the 500 m EZ and 500 m
buffer zone are required prior to rampup following any extended deactivation
of the array (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 is observed within or
approaching the 500 m EZ during this
pre-clearance period, ramp-up will not
be initiated until all marine mammals
have cleared the EZ. Criteria for clearing
the EZ will be as described above.
Ramp-up will be planned to occur
during periods of good visibility when
possible. However, ramp-up is allowed
at night and during poor visibility if the
500 m EZ and 500 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. Ramp-up
of the array may not occur at night or
during poor visibility if the PAM system
is not functional.
The operator is required to notify a
designated PSO of the planned start of
ramp-up as agreed-upon with the lead
PSO. A designated PSO must be notified
again immediately prior to initiating
ramp-up procedures and the operator
must receive confirmation from the PSO
to proceed. The operator must provide
information to PSOs documenting that
appropriate procedures were followed.
Following deactivation of the array for
reasons other than mitigation, the
operator is required to communicate the
near-term operational plan to the lead
PSO with justification for any planned
nighttime ramp-up.
L–DEO proposed that ramp up would
not occur following an extended power
down (LGL 2017). However, as we do
not allow extended power downs during
the planned surveys, we also do not
include this as a mitigation measure;
instead, ramp up is required after any
power down or shutdown of the array
(with the one exception as described
above). L–DEO also proposed that ramp
up would occur when the airgun array
begins operating after 8 minutes without
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airgun operations (LGL 2017). However,
we instead include the criteria for rampup as described above.
habitat, paying particular attention to
rookeries, mating grounds, and areas of
similar significance.
Vessel Strike Avoidance
Vessel strike avoidance measures are
intended to minimize the potential for
collisions with marine mammals. We
note that these requirements do not
apply in any case where compliance
would create an imminent and serious
threat to a person or vessel or to the
extent that a vessel is restricted in its
ability to maneuver and, because of the
restriction, cannot comply.
The vessel strike avoidance measures
include the following: Vessel operator
and crew will maintain a vigilant watch
for all marine mammals and slow down
or stop the vessel or alter course to
avoid striking any marine mammal. A
visual observer aboard the vessel will
monitor a vessel strike avoidance zone
around the vessel according to the
parameters stated below. Visual
observers monitoring the vessel strike
avoidance zone will be either thirdparty observers or crew members, but
crew members responsible for these
duties will be provided sufficient
training to distinguish marine mammals
from other phenomena. Vessel strike
avoidance measures will be followed
during surveys and while in transit.
The vessel will maintain a minimum
separation distance of 100 m from large
whales (i.e., baleen whales and sperm
whales). If a large whale is within 100
m of the vessel the vessel will reduce
speed and shift the engine to neutral,
and will not engage the engines until
the whale has moved outside of the
vessel’s path and the minimum
separation distance has been
established. If the vessel is stationary,
the vessel will not engage engines until
the whale(s) has moved out of the
vessel’s path and beyond 100 m. The
vessel will maintain a minimum
separation distance of 50 m from all
other marine mammals (with the
exception of short-beaked common
dolphins, dusky dolphins and southern
right whale dolphins that approach the
vessel, as described above). If an animal
is encountered during transit, the vessel
will attempt to remain parallel to the
animal’s course, avoiding excessive
speed or abrupt changes in course.
Vessel speeds will be reduced to 10
knots or less when mother/calf pairs,
pods, or large assemblages of cetaceans
are observed near the vessel.
Based on our evaluation of the
applicant’s proposed measures, NMFS
has determined that the mitigation
measures provide the means of effecting
the least practicable impact on the
affected species or stocks and their
Monitoring and Reporting
In order to issue an IHA for an
activity, Section 101(a)(5)(D) of the
MMPA states that NMFS must set forth
requirements pertaining to the
monitoring and reporting of such taking.
The MMPA implementing regulations at
50 CFR 216.104(a)(13) indicate that
requests for authorizations must include
the suggested means of accomplishing
the necessary monitoring and reporting
that will result in increased knowledge
of the species and of the level of taking
or impacts on populations of marine
mammals that are expected to be
present in the action area. Effective
reporting is critical both to compliance
as well as ensuring that the most value
is obtained from the required
monitoring.
Monitoring and reporting
requirements prescribed by NMFS
should contribute to improved
understanding of one or more of the
following:
• Occurrence of marine mammal
species or stocks in the area in which
take is anticipated (e.g., presence,
abundance, distribution, density);
• Nature, scope, or context of likely
marine mammal exposure to potential
stressors/impacts (individual or
cumulative, acute or chronic), through
better understanding of: (1) Action or
environment (e.g., source
characterization, propagation, ambient
noise); (2) affected species (e.g., life
history, dive patterns); (3) co-occurrence
of marine mammal species with the
action; or (4) biological or behavioral
context of exposure (e.g., age, calving or
feeding areas);
• Individual marine mammal
responses (behavioral or physiological)
to acoustic stressors (acute, chronic, or
cumulative), other stressors, or
cumulative impacts from multiple
stressors;
• How anticipated responses to
stressors impact either: (1) Long-term
fitness and survival of individual
marine mammals; or (2) populations,
species, or stocks;
• Effects on marine mammal habitat
(e.g., marine mammal prey species,
acoustic habitat, or other important
physical components of marine
mammal habitat); and
• Mitigation and monitoring
effectiveness.
L–DEO 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
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56145
monitoring of the EZ to inform potential
power downs or shutdowns of the
airgun array, are described above.
L–DEO’s monitoring and reporting
plan includes the following measures:
Vessel-Based Visual Monitoring
As described above, PSO observations
will take place during daytime airgun
operations and nighttime start ups (if
applicable) of the airguns. During
seismic operations, at least four visual
PSOs will be based aboard the Langseth.
PSOs will be appointed by L–DEO with
NMFS approval. During the majority of
seismic operations, two PSOs will
monitor for marine mammals around
the seismic vessel. Use of two
simultaneous observers increases the
effectiveness of detecting animals
around the source vessel. However,
during meal times, only one PSO may
be on duty. PSOs will be on duty in
shifts of duration no longer than 4
hours. Other crew will also be
instructed to assist in detecting marine
mammals and in implementing
mitigation requirements (if practical).
During daytime, PSOs will scan the area
around the vessel systematically with
reticle binoculars (e.g., 7 x 50 Fujinon),
Big-eye binoculars (25 x 150), and with
the naked eye.
PSOs will 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 will be
used to estimate numbers of animals
potentially ‘taken’ by harassment (as
defined in the MMPA). They will also
provide information needed to order a
power down or shutdown of airguns
when a marine mammal is within or
near the EZ.
When a sighting is made, the
following information about the sighting
will be recorded:
1. Species, group size, age/size/sex
categories (if determinable), behavior
when first sighted and after initial
sighting, heading (if consistent), bearing
and distance from seismic vessel,
sighting cue, apparent reaction to the
airguns or vessel (e.g., none, avoidance,
approach, paralleling, etc.), and
behavioral pace; and
2. Time, location, heading, speed,
activity of the vessel, sea state,
visibility, and sun glare.
All observations and power downs or
shutdowns will be recorded in a
standardized format. Data will be
entered into an electronic database. The
accuracy of the data entry will be
verified by computerized data validity
checks as the data are entered and by
subsequent manual checking of the
database. These procedures will allow
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initial summaries of data to be prepared
during and shortly after the field
program and will 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 will
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 will provide:
1. The basis for real-time mitigation
(airgun power down or shutdown);
2. Information needed to estimate the
number of marine mammals potentially
taken by harassment, which must be
reported to NMFS;
3. Data on the occurrence,
distribution, and activities of marine
mammals in the area where the seismic
study is conducted;
4. Information to compare the
distance and distribution of marine
mammals relative to the source vessel at
times with and without seismic activity;
and
5. Data on the behavior and
movement patterns of marine mammals
seen at times with and without seismic
activity.
Vessel-Based Passive Acoustic
Monitoring
As described above, the acoustic PSO
will monitor the PAM system in real
time. When a vocalization is detected,
the acoustic PSO will take necessary
action depending on the species and
location of the animal detected, whether
immediately calling for a shutdown or
immediately contacting visual PSOs to
alert them to the presence of marine
mammals in order to facilitate a power
down or shutdown, if required.
PAM will also take place to
complement the visual monitoring
program as described above. Please see
the Mitigation section above for a
description of the PAM system and the
acoustic PSO’s duties. The acoustic PSO
will 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 will also be
recorded for further analysis.
Reporting
A report will be submitted to NMFS
within 90 days after the end of the
cruise. The report will describe the
operations that were conducted and
sightings of marine mammals near the
operations. The report will provide full
documentation of methods, results, and
interpretation pertaining to all
monitoring. The 90-day report will
summarize the dates and locations of
seismic operations, and all marine
mammal sightings (dates, times,
locations, activities, associated seismic
survey activities). The report will also
include estimates of the number and
nature of exposures that occurred above
the harassment threshold based on PSO
observations, including an estimate of
those on the trackline but not detected.
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 planned
seismic surveys to be similar in nature.
Where there are meaningful differences
between species or stocks, or groups of
species, in anticipated individual
responses to activities, impact of
expected take on the population due to
differences in population status, or
impacts on habitat, NMFS has identified
species-specific factors to inform the
analysis. As described above, we
authorize only the takes estimated to
occur outside of New Zealand territorial
sea (Tables 10, 11, 12 and 13); however,
for the purposes of our negligible impact
analysis and determination, we consider
the total impacts to the affected marine
mammal populations resulting from the
specified activity, including takes that
are expected to occur within the
territorial sea (Table 14).
TABLE 14—TOTAL NUMBERS OF POTENTIAL INCIDENTAL TAKE OF MARINE MAMMALS DURING PORTIONS OF L–DEO’S
NORTH ISLAND 2-D, NORTH ISLAND 3-D, AND SOUTH ISLAND 2-D SURVEYS THAT OCCUR IN THE NEW ZEALAND TERRITORIAL SEA
Estimated
Level A takes 1
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Species
Estimated
Level B takes 1
Total
estimated
Level A and
Level B takes 1
0
0
0
0
0
0
0
25
11
24
14
16
16
16
25
11
24
14
16
16
16
Southern right whale ....................................................................................................................
Pygmy right whale .......................................................................................................................
Humpback whale .........................................................................................................................
Bryde’s whale ..............................................................................................................................
Common minke whale .................................................................................................................
Antarctic minke whale ..................................................................................................................
Sei whale .....................................................................................................................................
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TABLE 14—TOTAL NUMBERS OF POTENTIAL INCIDENTAL TAKE OF MARINE MAMMALS DURING PORTIONS OF L–DEO’S
NORTH ISLAND 2-D, NORTH ISLAND 3-D, AND SOUTH ISLAND 2-D SURVEYS THAT OCCUR IN THE NEW ZEALAND TERRITORIAL SEA—Continued
Estimated
Level A takes 1
Species
Estimated
Level B takes 1
Total
estimated
Level A and
Level B takes 1
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
1
3
0
0
0
0
0
0
25
6
278
251
251
169
169
169
85
334
169
251
85
85
486
918
518
291
195
291
184
789
368
166
394
1
21
2141
98
69
35
25
6
278
251
251
169
169
169
85
334
169
251
85
85
486
918
518
291
195
291
184
789
368
167
397
1
21
2141
98
69
35
Fin whale .....................................................................................................................................
Blue whale ...................................................................................................................................
Sperm whale ................................................................................................................................
Cuvier’s beaked whale ................................................................................................................
Arnoux’s beaked whale ...............................................................................................................
Southern bottlenose whale ..........................................................................................................
Shepard’s beaked whale .............................................................................................................
Hector’s beaked whale ................................................................................................................
True’s beaked whale ...................................................................................................................
Gray’s beaked whale ...................................................................................................................
Andrew’s beaked whale ...............................................................................................................
Strap-toothed whale .....................................................................................................................
Blainville’s beaked whale .............................................................................................................
Spade-toothed whale ...................................................................................................................
Bottlenose dolphin .......................................................................................................................
Short-beaked common dolphin ....................................................................................................
Dusky dolphin ..............................................................................................................................
Southern right-whale dolphin .......................................................................................................
Risso’s dolphin .............................................................................................................................
False killer whale .........................................................................................................................
Killer whale ..................................................................................................................................
Long-finned pilot whale ................................................................................................................
Short-finned pilot whale ...............................................................................................................
Pygmy sperm whale ....................................................................................................................
Hourglass dolphin ........................................................................................................................
Hector’s dolphin ...........................................................................................................................
Spectacled porpoise ....................................................................................................................
New Zealand fur seal ..................................................................................................................
New Zealand sea lion ..................................................................................................................
Southern elephant seal ................................................................................................................
Leopard seal ................................................................................................................................
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Note: NMFS does not authorize the estimated takes shown in the territorial sea.
1 Includes additional 25 percent contingency for potential additional survey operations and additional 25 percent contingency to account for uncertainties in density estimates.
NMFS does not anticipate that serious
injury or mortality will occur as a result
of L–DEO’s planned surveys, even in the
absence of mitigation. As discussed in
the Potential Effects section, nonauditory physical effects, stranding, and
vessel strike are not expected to occur.
We authorize a limited number of
instances of Level A harassment of 21
marine mammal species (Tables 10, 11,
12 and 13). However, we believe that
any PTS incurred in marine mammals
as a result of the planned activity would
be in the form of only a small degree of
PTS, not severe hearing impairment,
and would be unlikely to affect the
fitness of any individuals, because of
the constant movement of both the
Langseth and of the marine mammals in
the project 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
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marine mammals would be likely to
move away from a sound source that
represents an aversive stimulus,
especially at levels that would be
expected to result in PTS, given
sufficient notice of the Langseth’s
approach due to the vessel’s relatively
low speed when conducting seismic
surveys. We expect that the majority of
takes would be in the form of short-term
Level B behavioral harassment in the
form of temporary avoidance of the area
or decreased foraging (if such activity
were occurring), reactions that are
considered to be of low severity and
with no lasting biological consequences
(e.g., Southall et al., 2007).
Potential impacts to marine mammal
habitat are discussed in the Federal
Register notice of the proposed IHA (82
FR 45116; September 27, 2017) and are
summarized below. 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
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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 longterm 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.
Prey species are mobile and are
broadly distributed throughout the
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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 longterm 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 planned project area.
As described above, the take estimates
shown in Tables 10, 11, 12 and 13 have
been revised slightly since we published
the notice of the proposed IHA in the
Federal Register (82 FR 45116;
September 27, 2017). We have fully
considered these revised take estimates
in our negligible impact analysis.
Additionally, the acoustic ‘‘footprint’’ of
the planned surveys is small relative to
the ranges of the marine mammals
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
planned survey area.
The 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 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 mitigation.
The ESA-listed marine mammal
species under our jurisdiction that are
likely to be taken by the planned
surveys include the southern right, sei,
fin, blue, and sperm whale (listed as
endangered) and the South Island
Hector’s dolphin (listed as threatened).
We authorize a very limited amount of
take for these species (Tables 10, 11, 12
and 13), relative to their population
sizes, therefore we do not expect
population-level impacts to any of these
species. The other marine mammal
species that may be taken by harassment
during the planned surveys are not
listed as threatened or endangered
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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 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 L–DEO’s planned 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.
In summary and as described above,
the following factors primarily support
our determination that the impacts
resulting from this activity are not
expected to adversely affect the marine
mammal species or stocks through
effects on annual rates of recruitment or
survival:
• No serious injury or mortality is
anticipated or authorized;
• The anticipated impacts of the
planned activity on marine mammals
would primarily be temporary
behavioral changes due to avoidance of
the area around the survey vessel;
• The number of instances of PTS
that may occur are expected to be very
small in number (Tables 10, 11, 12 and
13). 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 planned surveys
to avoid exposure to sounds from the
activity;
• The planned project area does not
contain known 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
planned surveys would be temporary
and spatially limited; and
• The 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
monitoring and mitigation measures,
NMFS finds that the total marine
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mammal take from the planned activity
will have a negligible impact on all
affected marine mammal species or
stocks.
Small Numbers
As noted above, only small numbers
of incidental take may be authorized
under Section 101(a)(5)(D) of the MMPA
for specified activities other than
military readiness activities. The MMPA
does not define small numbers; so, in
practice, where estimated numbers are
available, NMFS compares the number
of individuals taken to the most
appropriate estimation of abundance of
the relevant species or stock in our
determination of whether an
authorization is limited to small
numbers of marine mammals.
Additionally, other qualitative factors
may be considered in the analysis, such
as the temporal or spatial scale of the
activities. Tables 10, 11, 12 and 13
provide numbers of take by Level A
harassment and Level B harassment
authorized. These are the numbers we
use for purposes of the small numbers
analysis.
The numbers of marine mammals that
we authorize to be taken would be
considered small relative to the relevant
populations (less than 12 percent for all
species) for the species for which
abundance estimates are available. No
known current worldwide or regional
population estimates are available for
ten species under NMFS’ jurisdiction
that could be incidentally taken as a
result of the planned surveys: the
pygmy right whale; pygmy sperm
whale; True’s beaked whale; shortfinned pilot whale; false killer whale;
bottlenose dolphin; short-beaked
common dolphin; southern right whale
dolphin; Risso’s dolphin; and
spectacled porpoise.
NMFS has reviewed the geographic
distributions and habitat preferences of
these species in determining whether
the numbers of takes authorized herein
are likely to represent small numbers.
Pygmy right whales have a circumglobal
distribution and occur throughout
coastal and oceanic waters in the
Southern Hemisphere (between 30 to
55° South) (Jefferson et al., 2008).
Pygmy sperm whales occur in deep
waters on the outer continental shelf
and slope in tropical to temperate
waters of the Atlantic, Indian, and
Pacific Oceans. True’s beaked whales
occur in the Southern hemisphere from
the western Atlantic Ocean to the Indian
Ocean to the waters of southern
Australia and possibly New Zealand
(Jefferson et al., 2008). False killer
whales generally occur in deep offshore
tropical to temperate waters (between
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Federal Register / Vol. 82, No. 226 / Monday, November 27, 2017 / Notices
ethrower on DSK3G9T082PROD with NOTICES
50° North to 50° South) of the Atlantic,
Indian, and Pacific Oceans (Jefferson et
al., 2008). Southern right whale
dolphins have a circumpolar
distribution and generally occur in deep
temperate to sub-Antarctic waters in the
Southern Hemisphere (between 30 to
65° South) (Jefferson et al., 2008). Shortfinned pilot whales are found in warm
temperate to tropical waters throughout
the world, generally in deep offshore
areas (Olson and Reilly, 2002).
Bottlenose dolphins are distributed
worldwide through tropical and
temperate inshore, coastal, shelf, and
oceanic waters (Leatherwood and
Reeves 1990, Wells and Scott 1999,
Reynolds et al. 2000). Spectacled
porpoises are believed to have a range
that is circumpolar in the sub-Antarctic
zone (with water temperatures of at least
1–10 °C) (Goodall 2002). The Risso’s
dolphin is a widely-distributed species,
inhabiting primarily deep waters of the
continental slope and outer shelf
(especially with steep bottom
topography), from the tropics through
the temperate regions in both
hemispheres (Kruse et al. 1999). The
short-beaked common dolphin is an
oceanic species that is widely
distributed in tropical to cool temperate
waters of the Atlantic and Pacific
Oceans (Perrin 2002), from nearshore
waters to thousands of kilometers
offshore.
Based on the broad spatial
distributions and habitat preferences of
these species relative to the areas where
the planned surveys are planned to
occur, NMFS concludes that the
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18:49 Nov 24, 2017
Jkt 244001
authorized take of these species likely
represent small numbers relative to the
affected species’ overall population
sizes, though we are unable to quantify
the take numbers as a percentage of
population.
Based on the analysis contained
herein of the planned activity (including
the mitigation and monitoring
measures) and the anticipated take of
marine mammals, NMFS finds that
small numbers of marine mammals will
be taken relative to the population size
of the affected species.
Unmitigable Adverse Impact Analysis
and Determination
There are no relevant subsistence uses
of the affected marine mammal stocks or
species implicated by this action.
Therefore, NMFS has determined that
the total taking of affected species or
stocks will not have an unmitigable
adverse impact on the availability of
such species or stocks for taking for
subsistence purposes.
Endangered Species Act
Section 7(a)(2) of the Endangered
Species Act of 1973 (ESA: 16 U.S.C.
1531 et seq.) requires that each Federal
agency insure that any action it
authorizes, funds, or carries out is not
likely to jeopardize the continued
existence of any endangered or
threatened species or result in the
destruction or adverse modification of
designated critical habitat. To ensure
ESA compliance for the issuance of
IHAs, NMFS consults internally, in this
case with the ESA Interagency
Cooperation Division, whenever we
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56149
propose to authorize take for
endangered or threatened species.
The NMFS Permits and Conservation
Division is authorizing the incidental
take of six species of marine mammals
which are listed under the ESA (the
southern right, sei, fin, blue, and sperm
whale and South Island Hector’s
dolphin). Under section 7 of the ESA,
we initiated consultation with the
NMFS OPR Interagency Cooperation
Division for the issuance of this IHA. In
October, 2017, the NMFS OPR
Interagency Cooperation Division issued
a Biological Opinion with an incidental
take statement, which concluded that
the issuance of the IHA was not likely
to jeopardize the continued existence of
the southern right, sei, fin, blue, and
sperm whale and South Island Hector’s
dolphin. The Biological Opinion also
concluded that the issuance of the IHA
would not destroy or adversely modify
designated critical habitat for these
species.
Authorization
NMFS has issued an IHA to the
L–DEO for the potential harassment of
small numbers of 38 marine mammal
species incidental to marine geophysical
surveys in the southwest Pacific Ocean,
provided the previously mentioned
mitigation, monitoring and reporting
requirements are incorporated.
Dated: November 21, 2017.
Donna Wieting,
Director, Office of Protected Resources,
National Marine Fisheries Service.
[FR Doc. 2017–25516 Filed 11–24–17; 8:45 am]
BILLING CODE 3510–22–P
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Agencies
[Federal Register Volume 82, Number 226 (Monday, November 27, 2017)]
[Notices]
[Pages 56120-56149]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2017-25516]
[[Page 56119]]
Vol. 82
Monday,
No. 226
November 27, 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 Marine Geophysical Survey in the
Southwest Pacific Ocean, 2017/2018; Notice
Federal Register / Vol. 82 , No. 226 / Monday, November 27, 2017 /
Notices
[[Page 56120]]
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DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
RIN 0648-XF456
Takes of Marine Mammals Incidental to Specified Activities;
Taking Marine Mammals Incidental to a Marine Geophysical Survey in the
Southwest Pacific Ocean, 2017/2018
AGENCY: National Marine Fisheries Service (NMFS), National Oceanic and
Atmospheric Administration (NOAA), Commerce.
ACTION: Notice; issuance of an incidental harassment authorization.
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SUMMARY: In accordance with the regulations implementing the Marine
Mammal Protection Act (MMPA) as amended, notification is hereby given
that NMFS has issued an incidental harassment authorization (IHA) to
Lamont-Doherty Earth Observatory of Columbia University (L-DEO) to
incidentally harass, by Level A and Level B harassment only, marine
mammals during marine geophysical survey activities in the southwest
Pacific Ocean.
DATES: This Authorization is valid from October 27, 2017 through
October 26, 2018.
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, or 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
NMFS prepared an Environmental Assessment (EA) and analyzed the
potential impacts to marine mammals that would result from L-DEO's
planned surveys. A Finding of No Significant Impact (FONSI) was signed
on October 27, 2017. A copy of the EA and FONSI is available upon
request (see ADDRESSES).
Summary of Request
On May 17, 2017, NMFS received a request from L-DEO for an IHA to
take marine mammals incidental to conducting a marine geophysical
survey in the southwest Pacific Ocean. On September 13, 2017, we deemed
L-DEO's application for authorization to be adequate and complete. L-
DEO's request is for take of 38 species of marine mammals by Level B
harassment and Level A harassment. Neither L-DEO 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 Activity
Researchers from California State Polytechnic University,
California Institute of Technology, Pennsylvania State University,
University Southern California, University of Southern Mississippi,
University of Hawaii at Manoa, University of Texas, and University of
Wisconsin Madison, with funding from the U.S. National Science
Foundation, propose to conduct three high-energy seismic surveys from
the research vessel (R/V) Marcus G. Langseth (Langseth) in the waters
of New Zealand in the southwest Pacific Ocean in 2017/2018. The NSF-
owned Langseth is operated by L-DEO. One proposed survey would occur
east of North Island and would use an 18-airgun towed array with a
total discharge volume of ~3,300 cubic inches (in\3\). Two other
proposed seismic surveys (one off the east coast of North Island and
one south of South Island) would use a 36-airgun towed array with a
discharge volume of ~6,600 in\3\. The surveys would take place in water
depths from ~50 to >5,000 m.
The North Island two-dimensional (2-D) survey would consist of
approximately 35 days of seismic operations plus approximately 2 days
of transit and towed equipment deployment/retrieval. The Langseth would
depart Auckland on approximately October 26, 2017 and arrive in
Wellington on December 1, 2017. The North Island three-dimensional (3-
D) survey is proposed for approximately January 5, 2018-February 8,
2018 and would consist of approximately 33 days of seismic operations
plus approximately 2 days of transit and towed equipment deployment/
retrieval. The Langseth would leave and return to port in Napier. The
South Island 2-D survey is proposed for approximately February 15,
2018-March 15, 2018 and would consist of approximately 22 days of
seismic operations, approximately 3 days of transit, and approximately
7 days of ocean bottom seismometer (OBS) deployment/retrieval.
The proposed surveys would occur within the Exclusive Economic Zone
(EEZ) and territorial sea of New Zealand. The proposed North Island 2-D
survey would occur within ~37-43[deg] S. between 180[deg] E. and the
east coast of North Island along the Hikurangi margin. The proposed
North Island 3-D survey would occur over a 15 x 60 kilometer (km) area
offshore at the Hikurangi trench and forearc off North Island within
~38-39.5[deg] S., ~178-179.5[deg] E. The proposed South Island 2-D
survey would occur along the Puysegur margin off South Island within
~163-168[deg] E. between 50[deg] S. and the south coast of South
Island. Please see Figure 1 and Figure 2 in L-DEO's IHA application for
maps depicting the
[[Page 56121]]
specified geographic region of the proposed surveys.
A detailed description of the planned project is provided in the
Federal Register notice for the proposed IHA (82 FR 45116; September
27, 2017). Since that time, no changes have been made to the planned
activities. Therefore, a detailed description is not provided here.
Please refer to that Federal Register notice for the description of the
specific activity. Specifications of the airgun arrays, trackline
distances, and water depths of each of the three proposed surveys are
shown in Table 1.
Table 1--Specifications of Airgun Arrays, Trackline Distances, and Water Depths Associated With Three Planned R/
V Langseth Surveys off New Zealand
----------------------------------------------------------------------------------------------------------------
North Island 2-D survey North Island 3-D survey South Island 2-D survey
----------------------------------------------------------------------------------------------------------------
Airgun array configuration and total 36 airguns, four two separate 18-airgun 36 airguns, four
volume. strings, total volume arrays that would fire strings, total volume
of ~6,600 in\3\. alternately; each of ~6,600 in\3\.
array would have a
total discharge volume
of ~3,300 in\3\.
Tow depth of arrays.................. 9 m.................... 9 m.................... 9 m.
Shot point intervals................. 37.5 m................. 37.5 m *............... 50 m.
Source velocity (tow speed).......... 4.3 knots.............. 4.5 knots.............. 4.5 knots.
Water depths......................... 8%, 23%, and 69% of 0%, 42%, and 58% of 1%, 17%, and 82% of
line km would take line km would take line km would take
place in shallow (<100 place in shallow, place in shallow,
m), intermediate (100- intermediate, and deep intermediate, and deep
1,000 m), and deep water, respectively. water, respectively.
water (>1,000 m),
respectively.
Approximate trackline distance....... 5,398 km............... 3,025 km............... 4,876 km.
Percentage of survey tracklines Approximately 9 percent Approximately 1 percent Approximately 6
proposed in New Zealand Territorial percent.
Waters.
----------------------------------------------------------------------------------------------------------------
* The two arrays fire alternately with an approximate distance of 37.5 m traveled between the firing of one
array, then the other.
Comments and Responses
NMFS published a notice of proposed IHA in the Federal Register on
September 27, 2017 (82 FR 45116). During the 30-day public comment
period, NMFS received comments from the Marine Mammal Commission
(Commission), the Marine Seismic Research Oversight Committee (MSROC)
and from members of the general public. NMFS has posted the comments
online at: https://www.nmfs.noaa.gov/pr/permits/incidental. The
following is a summary of the public comments and NMFS' responses.
Comment 1: The Commission expressed concerns regarding L-DEO's
method to estimate the extent of the Level A and B harassment zones and
the numbers of marine mammal takes. The Commission stated that the
model is not the best available science because it assumes spherical
spreading, a constant sound speed, and no bottom interactions for
surveys in deep water. In light of their concerns, the Commission
recommended that NMFS require L-DEO to re-estimate the Level A and
Level B harassment zones and associated takes of marine mammals using
both operational (including number/type/spacing of airguns, tow depth,
source level/operating pressure, operational volume) and site-specific
environmental (including sound speed profiles, bathymetry, and sediment
characteristics at a minimum) parameters.
NMFS Response: NMFS understands the concerns expressed by the
Commission about L-DEO's current modeling approach for estimating Level
A and Level B harassment zones. L-DEO has conveyed to NMFS that
additional modeling efforts to refine the process and conduct
comparative analysis may be possible with the availability of research
funds and other resources. Obtaining research funds is typically
accomplished through a competitive process, including those submitted
to U.S. Federal agencies. The use of models for calculating buffer and
exclusion zone radii and for developing take estimates is not a
requirement of the MMPA incidental take authorization process.
Furthermore, NMFS does not provide specific guidance on model
parameters nor prescribe a specific model for applicants as part of the
MMPA incidental take authorization process at this time, although we do
review methods to ensure their adequacy for prediction of take.
L-DEO's application describes their approach to modeling Level A
and Level B harassment zones. In summary, L-DEO acquired field
measurements for several array configurations at shallow, intermediate,
and deep-water depths during acoustic verification studies conducted in
the northern Gulf of Mexico in 2007 and 2008; these were presented in
Tolstoy et al. (2009). Based on the empirical data from those studies,
L-DEO developed a sound propagation modeling approach that predicts
received sound levels as a function of distance from a particular
airgun array configuration in deep water (Diebold et al., 2010; NSF-
USGS 2011). For the planned surveys off the coast of New Zealand, L-DEO
modeled Level A and Level B harassment zones using the sound
propagation modeling approach described in Diebold et al. (2010), based
on the empirically-derived measurements from the Gulf of Mexico
calibration survey. For deep water (>1000 meters (m)), L-DEO used the
deep-water radii obtained from model results down to a maximum water
depth of 2,000 m (Figure 2 and 3 in Diebold et al., 2010); the radii
for intermediate water depths (100-1,000 m) were derived from the deep-
water radii by applying a correction factor (multiplication) of 1.5
(Fig. 16 in Diebold et al., 2010); the radii for shallow-water depths
(<100 m) were derived by applying a scaling factor to the empirically
derived measurements from the Gulf of Mexico calibration survey
(Tolstoy et al., 2009) to account for the differences in tow depth
between the Gulf of Mexico calibration survey (6 m) and the planned New
Zealand surveys (9 and 12 m).
In 2015, L-DEO explored the question of whether the Gulf of Mexico
calibration data adequately informs the model to predict isopleths in
other areas by conducting a retrospective sound power analysis of one
of the lines acquired during a L-DEO seismic survey offshore New Jersey
in 2014 (Crone, 2015). NMFS presented a comparison of the predicted
radii (i.e.,
[[Page 56122]]
modeled isopleths to distances corresponding to Level A and Level B
harassment thresholds) with radii based on in situ measurements in a
previous notice of issued Authorization for Lamont-Doherty (see 80 FR
27635; May 14, 2015, Table 1).
Briefly, Crone's (2015) analysis, specific to the survey site
offshore New Jersey, confirmed that in-situ, site specific measurements
and estimates of 160 decibels (dB) root mean square (rms) and 180 dB
rms isopleths collected by the Langseth's hydrophone streamer in
shallow water were smaller than the modeled (i.e., predicted) zones for
two seismic surveys conducted offshore New Jersey in shallow water in
2014 and 2015. In that particular case, Crone's (2015) results showed
that L-DEO's modeled 180 dB rms and 160 dB rms zones were approximately
28 percent and 33 percent larger, respectively, than the in-situ, site-
specific measurements, thus confirming that L-DEO's model was
conservative in that case. The following is a summary of two additional
analyses of in-situ data that support L-DEO's use of the modeled Level
A and Level B harassment zones in this particular case.
In 2010, L-DEO assessed the accuracy of their modeling approach by
comparing the sound levels of the field measurements acquired in the
Gulf of Mexico study to their model predictions (Diebold et al., 2010).
They reported that the observed sound levels from the field
measurements fell almost entirely below the predicted mitigation radii
curve for deep water (greater than 1,000 m; 3280.8 feet (ft)) (Diebold
et al., 2010).
In 2012, L-DEO used a similar process to model distances to
isopleths corresponding to the isopleths corresponding to Level A and
Level B harassment thresholds for a shallow-water seismic survey in the
northeast Pacific Ocean offshore Washington State. L-DEO conducted the
shallow-water survey using the same airgun configuration planned for
the surveys considered in this IHA (i.e., 6,600 cubic inches (in\3\))
and recorded the received sound levels on both the shelf and slope
using the Langseth's 8 kilometer (km) hydrophone streamer. Crone et al.
(2014) analyzed those received sound levels from the 2012 survey and
confirmed that in-situ, site specific measurements and estimates of the
160 dB rms and 180 dB rms isopleths collected by the Langseth's
hydrophone streamer in shallow water were two to three times smaller
than L-DEO's modeling approach had predicted. While the results
confirmed bathymetry's role in sound propagation, Crone et al. (2014)
were also able to confirm that the empirical measurements from the Gulf
of Mexico calibration survey (the same measurements used to inform L-
DEO's modeling approach for the planned surveys in the southwest
Pacific Ocean) overestimated the size of the predicted isopleths for
the shallow-water 2012 survey off Washington State and were thus
precautionary, in that particular case.
NMFS continues to work with L-DEO to address the issue of
incorporating site-specific information for future authorizations for
seismic surveys. However, L-DEO's current modeling approach (supported
by the three studies discussed previously) represents the best
available information for NMFS to reach determinations for this IHA. As
described earlier, the comparisons of L-DEO's model results and the
field data collected in the Gulf of Mexico, offshore Washington State,
and offshore New Jersey illustrate a degree of conservativeness built
into L-DEO's model for deep water, which NMFS expects to offset some of
the limitations of the model to capture the variability resulting from
site-specific factors. Based upon the best available information (i.e.,
the three data points, two of which are peer-reviewed, discussed in
this response), NMFS finds that the Level A and Level B harassment zone
calculations are appropriate for use in this particular IHA.
Additionally, results of acoustic modeling represent just one component
of the analysis during the MMPA authorization process, as NMFS also
takes into consideration other factors associated with the activity
(e.g., geographic location, duration of activities, context, sound
source intensity, etc.).
Comment 2: The Commission recommended that NMFS use a different
data source to estimate densities of New Zealand fur seals and southern
elephant seals than was used in the proposed IHA. Specifically, the
Commission recommended that NMFS rely on the data presented in the U.S.
Navy Marine Species Density Database (NMSDD) to estimate take of these
pinniped species. The Commission also recommended that NMFS convene an
internal working group to determine what data sources are considered
best available for the various species and in the various areas and
provide that information to applicants accordingly.
NMFS Response: Density data presented in Bonnell et al. (1992) was
used in this particular IHA because it was based on systematic aerial
at-sea surveys (off Oregon and Washington), whereas the data presented
in NMSDD was derived from surveys of hauled out pinnipeds. While the
NMSDD data is more recent than the data presented in Bonnell et al.
(1992), in this case we determined that densities presented in Bonnell
et al. (1992), which were derived from at-sea surveys, would be more
representative of densities for similar taxonomic species in a
different area (in this case, New Zealand). It is important to note
that the NMSDD data are specific to the west coast of the U.S. and were
based on population sizes for the species in the particular geographic
ranges for the particular geographic areas of concern for the U.S.
Navy, and are therefore useful in estimating densities for those same
species in those same particular geographic areas. However, in this
case the densities reported for pinnipeds off the U.S. west coast were
used to estimate densities of surrogate species in a different
geographic area (New Zealand). Thus our selection of the data from
Bonnell et al. (1992) to extrapolate pinniped densities in New Zealand
for this IHA was based on a preference to use data that was based on
at-sea surveys to estimate at-sea density. While we acknowledge the
usefulness of the NMSDD data for calculating marine mammal densities
for ITAs for activities that occur on the U.S. west coast, that does
not preclude us from relying on other data sources when activities are
planned to occur outside the U.S. In summary, while NMFS has used NMSDD
density data to estimate take of pinnipeds in previous ITAs for
activities that occurred off the west coast of the U.S., NMFS
determined that, for this particular IHA, Bonnell et al. (1992)
represented the best available information for the marine mammals in
the survey area.
Regarding the Commission's recommendation that NMFS convene an
internal working group to determine what data sources are considered
best available for the various species and in the various areas, NMFS
may consider future action to address these issues, but currently
intends to address these questions through ongoing interactions with
the U.S. Navy, academic institutions, and other organizations.
Comment 3: The Commission recommended that NMFS adjust density
estimates using some measure of uncertainty (i.e., coefficient of
variation, standard deviation, standard error) rather than the proposed
25 percent contingency, and recommended that NMFS convene a working
group to determine how best to incorporate uncertainty in density data
that are extrapolated.
NMFS Response: The Commission has recommended previously that NMFS
[[Page 56123]]
adjust density estimates using some measure of uncertainty when
available density data originate from different geographic areas,
temporal scales, and species, especially for actions which will occur
outside the U.S. EEZ where site- and species-specific density estimates
tend to be scant, such as L-DEO's planned survey. We have attempted to
do so in this IHA, and feel the 25 percent correction factor is an
appropriate method in this case to account for uncertainties in the
density data that was available for use in the take estimates. NMFS is
open to consideration of other correction factors for use in future
IHAs and looks forward to further discussion with the Commission on how
best to incorporate uncertainty in density estimates in instances where
density data is limited.
Regarding the recommendation that NMFS convene a working group to
determine how best to incorporate uncertainty in density data that are
extrapolated, NMFS may consider future action to address these issues,
but currently intends to address these questions through ongoing
interactions with the U.S. Navy, academic institutions, and other
organizations.
Comment 4: The Commission expressed concern regarding methods used
to estimate the numbers of takes, including the use of rounding in
calculations and recommended that NMFS share the rounding criteria with
the Commission.
NMFS Response: NMFS appreciates the Commission's ongoing concern in
this matter. Calculating predicted takes is not an exact science and
there are arguments for taking different mathematical approaches in
different situations, and for making qualitative adjustments in other
situations. We believe, however, that the methodology used for take
calculation in this IHA, as described in detail in the Federal Register
notice of the proposed IHA (82 FR 45116; September 27, 2017), remains
appropriate. NMFS continues to refine the rounding criteria and will
share the criteria with the Commission upon its finalization.
Comment 5: The Commission recommended that NMFS authorize Level A
take based on group size of the species when Level A take is
anticipated and when the estimated Level A take of a species was less
than the group size for the species.
NMFS Response: NMFS considered this recommendation but ultimately
concluded that, given the modeled Level A harassment zones in concert
with the mitigation measures required in the IHA, it was not realistic
to assume a single take by Level A harassment of an individual animal
would translate to an entire group of that species being taken by Level
A harassment, in all instances. The assumption that if a single
individual is taken then an entire group would be taken only applies in
the case of instantaneous exposure, as it is extremely unlikely than an
entire group of animals would remain within an area long enough to be
taken by an accumulation of energy (SELcum). Therefore, in
analyzing this question, we only considered the potential for Level A
take of an entire group of the species in the context of peak sound
pressure level (SPL). The modeled Level A zones (peak SPL) for marine
mammal functional hearing groups are relatively small, especially in
the cases of low-frequency cetaceans, mid-frequency cetaceans, phocid
pinnipeds and otariid pinnipeds, for which the modeled Level A zones
(peak SPL) are all estimated to be less than 50 m (Tables 6, 7 and 8).
Coupled with the fact that shutdown of the airguns is required for
marine mammals within 100 m of the array (with the exception of short-
beaked common dolphins, dusky dolphins and southern right whale
dolphins that approach the vessel), it is very unlikely that an entire
group of any species of marine mammals in these functional hearing
groups would be exposed to the airgun array at levels that would
constitute Level A harassment. For instance, in the case of short-
finned pilot whales, one take by Level A harassment is estimated during
the North Island 2-D survey (Table 10). Though we are not aware of
information on the typical group size for short-finned pilot whales off
New Zealand, Ross (2006) reported that short-finned pilot whales off
Australia tend to occur in groups of 10-30 individuals. The Level A
harassment zone (SPL) for short-finned pilot whales (considered to be
in the mid-frequency functional hearing group) for the North Island 2-D
survey is estimated to be less than 14 m (Table 6). We believe the
possibility of a group of 10-30 short-finned pilot whales approaching
within 14 m of the airgun array and being taken by Level A harassment,
especially considering the mitigation requirement that the array be
shut down entirely if a pilot whale approaches within 100 m of the
array, is so low as to be discountable.
Even in the case of short-beaked common dolphins, dusky dolphins
and southern right whale dolphins that approach the vessel, for which
the power down requirement does not apply, we believe the likelihood
that a group of bow-riding dolphins would occur within 14 m of the
array to be so low as to be discountable. For instance, though common
dolphin group size varies depending on season, depth, sea surface
temperature, Stockin (2008) reported the most frequently observed group
size in the Hauraki Gulf to be 21-30 animals. We believe the
possibility of a group of 21-30 dolphins approaching within 14 m of the
airgun array and being taken by Level A harassment is so low as to be
discountable. Therefore, for the species categorized as low-frequency
cetaceans, mid-frequency cetaceans, phocid pinnipeds and otariid
pinnipeds, we do not authorize Level A take by group size, when at
least one take is estimated to occur for the species.
The Level A harassment zones (peak SPL) for high-frequency
cetaceans are estimated at 229.2 m, 119.0 m, and 229.2 m, for the North
Island 2-D, North Island 3-D, and South Island 2-D surveys,
respectively. We analyzed the potential for a group of any of the
species in the high-frequency functional hearing group (that occur in
the survey areas) occurring between 229.2 m (largest distance to the
isopleth corresponding to the Level A harassment threshold) and 100 m
(the distance to the 100 m exclusion zone (EZ) for the smallest element
in the array, for all species in the high-frequency functional hearing
group) of the array. The species in this group for which Level A take
is authorized in this IHA include the hourglass dolphin, spectacled
porpoise and pygmy sperm whale. We are not aware of information on the
group sizes of these species in the waters off New Zealand. However,
based on the best available information, estimated group sizes are
lower than the number of takes authorized, when at least 1 Level A take
is authorized, for these species: Hourglass dolphin group size was
reported as averaging 2-6 individuals in Antarctic waters (Santora,
2012) whereas 15, 10, and 12 takes by Level A harassment are authorized
(for North Island 2-D, North Island 3-D, and South Island 2-D survey,
respectively); spectacled porpoise group size was reported as 2
individuals in Antarctic waters (Sekiguchi et al., 2006), whereas 6
takes by Level A harassment are authorized for the South Island 2-D
survey (with 0 Level A takes predicted for the North Island 2-D and
North Island 3-D surveys); Kogia spp. mean group size was reported as
1.9 individuals in the California current ecosystem (Barlow, 2010)
whereas 6, 4, and 5 takes by Level A harassment are authorized (for
North Island 2-D, North Island 3-D, and South Island 2-D survey,
respectively). Because the number of
[[Page 56124]]
authorized Level A takes are higher than the respective group sizes for
these species, we do not authorize Level A take by group size, when at
least one take is estimated to occur for the species, for any marine
mammal species.
Comment 6: The Commission recommended that NMFS include a take
table showing the total numbers of takes for the entire activity area
(territorial seas, exclusive economic zones, and high seas).
NMFS Response: NMFS does not authorize takes in the territorial
sea. However, we have included a table showing the take estimates in
the New Zealand territorial sea (see Table 14).
Comment 7: The Commission recommended that NMFS include pygmy and
gingko-toothed beaked whales and dwarf sperm whales in the IHA, based
on range estimates and stranding records in New Zealand for these
species.
NMFS Response: NMFS has reviewed the available literature available
on the strandings of these three species. While stranding records exist
for these species in various locations on the coast of New Zealand,
these strandings appear to have been isolated events in all cases and
do not suggest that the density of these species in the survey area is
such that take of these species is likely to occur. Therefore, we do
not authorize take of ginkgo-toothed beaked whales, pygmy beaked
whales, and dwarf sperm whales in this IHA.
Comment 8: The Commission recommended that NMFS prohibit L-DEO from
using power downs during its survey.
NMFS Response: NMFS agrees with the Commission that limiting the
use of power downs can be beneficial in reducing the overall sound
input in the marine environment from geophysical surveys; as such, NMFS
is requiring that power downs in this IHA occur for no more than a
maximum of 30 minutes at any time. NMFS is still in the process of
determining best practice, via solicitation of public comment, for the
use of power downs as a mitigation measure in ITAs for geophysical
surveys. We will take into consideration the Commission's
recommendation that power downs be eliminated as a mitigation measure
as we work toward a determination on best practices for the use of
power downs in IHAs for marine geophysical surveys. Ultimately our
determination will be based on the best available science and will be
communicated clearly to ITA applicants.
Comment 9: The Commission recommended that NMFS condition the IHA
to require LDEO to abide by the regulatory requirements of New
Zealand's Exclusive Economic Zone and Continental Shelf Act and,
through it, the mandatory provisions of the 2013 Code of Conduct for
Minimizing Acoustic Disturbance to Marine Mammals from Seismic Survey
Operations (Code).
NMFS Response: NMFS does not have the statutory authority to
require L-DEO to abide by the regulatory requirements of New Zealand's
Exclusive Economic Zone and Continental Shelf Act and, through it, the
mandatory provisions of the Code. Under the MMPA, L-DEO must comply
with the requirements of the IHA. However, we also encourage L-DEO to
comply with the provisions of the Code to the extent possible.
Comment 10: The Commission recommended that NMFS include a
mitigation measure requiring shutdown of the airgun array upon
observation of a large whale with calf or an aggregation of large
whales at any distance, in an effort to minimize impacts on mysticetes
and sperm whales that are engaged in biologically-important behaviors
(e.g., nursing, breeding, feeding).
NMFS Response: NMFS has included mitigation measures in the final
IHA requiring shutdown of the airgun array upon observation of a large
whale with calf and upon observation of an aggregation of large whales
at any distance, as recommended by the Commission. See the section on
Mitigation, below, for more details.
Comment 11: The Commission recommended that NMFS incorporate
mitigation measures that would require both visual observations and
passive acoustic methods to implement shutdown procedures when any
sperm whale, beaked whale, or Kogia spp. are detected, which would
bolster mitigation efforts as a whole, affording NMFS the ability to
further reduce the impacts on those deep-diving species. The Commission
also recommended a consistent approach for requiring all geophysical
and seismic survey operators to abide by the same general mitigation
measures.
NMFS Response: NMFS has included a mitigation measure in the final
IHA requiring shutdown of the airgun array upon acoustic detection of a
beaked whale, sperm whale, or Kogia spp., as recommended by the
Commission, with an exception for sperm whales in instances where the
acoustic detection can be definitively localized and the sperm whale is
confirmed to be located outside the 500 m exclusion zone. See the
Response to Comment 13 and the section on Mitigation, below, for
further details, including the reasoning behind the shutdown
requirement upon acoustic detection and the sperm whale exception.
NMFS considered requirement of shutdown upon visual detection of
sperm whales at any distance. We have included a mitigation measure
that would require shutdown of the array on acoustic detection of sperm
whales at any distance (except in instances where the sperm whale can
be definitively localized as being located outside the 500 m EZ). The
reasoning behind the shutdown requirement upon acoustic detection is
provided in more detail below (see section on Mitigation). Based on the
best available information, we believe that acoustic detections of
sperm whales would most likely be representative of the foraging
behavior we intend to minimize disruption of, while visual observations
of sperm whales would represent resting between bouts of such behavior.
Occurrence of resting sperm whales at distances beyond the 500 m
exclusion zone may not indicate a need to implement shutdown.
Therefore, this measure has not been added to the final IHA. This is
discussed in greater detail in the Mitigation section, below.
NMFS agrees with the Commission that consistency in mitigation
measures across incidental take authorizations (ITAs) for similar
activities is a worthwhile goal, to the extent practicable. However,
NMFS also must determine the most appropriate mitigation measures for a
given ITA, taking into account factors unique to that ITA, such as the
type, extent, location, and timing of activities, and therefore,
complete consistency in mitigation measures across ITAs for similar
activities will not always be possible. NMFS is still in the process of
determining best practice, via solicitation of public comment, for the
use of a suite of mitigation measures in ITAs for marine geophysical
surveys. We will take into consideration the Commission's
recommendations with regard to mitigation measures as we work toward
determinations on best practices for mitigation measures in IHAs for
geophysical surveys. Ultimately our determination will be based on the
best available science and will be communicated clearly to ITA
applicants.
Comment 12: The Commission expressed concern that reporting of the
manner of taking and the numbers of animals incidentally taken should
account for all animals in the various survey areas, including those
animals directly on the trackline that are not detected, and how well
animals are
[[Page 56125]]
detected based on the distance from the observer (accounted for by g(0)
and f(0) values). The Commission has recommended a method for
estimating the number of cetaceans in the vicinity of geophysical
surveys based on the number of groups detected and recommended that
NMFS require L-DEO to use this method for estimating g(0) and f(0)
values to better estimate the numbers of marine mammals taken by Level
A and Level B harassment.
NMFS Response: NMFS agrees that reporting of the manner of taking
and the numbers of animals incidentally taken should account for all
animals taken, including those animals directly on the trackline that
are not detected and how well animals are detected based on the
distance from the observer, to the extent practicable. NMFS appreciates
the Commission's recommendations but we believe that the Commission's
described method needs further consideration in relation to the
observations conducted during marine geophysical surveys. Therefore, at
this time we do not prescribe a particular method for accomplishing
this task. We look forward to engaging further both L-DEO, the
Commission and other applicants to reach a determination on the most
suitable method to for estimating g(0) and f(0) values.
Comment 13: A member of the general public expressed concern
regarding the effective dates of the IHA and that there had not been
adequate consultation within New Zealand, including that the local
indigenous populations were not consulted.
NMFS Response: NMFS has followed and met its statutory obligations
with respect to notifying the public of, and requesting comments on,
the proposed IHA, and has considered and responded to all public
comments received. With respect to concerns regarding communication
within New Zealand, including with indigenous groups, NMFS does not
have the authority to require communication between L-DEO and the New
Zealand government or interested parties within New Zealand. In
addition, the MMPA provides authority only to authorize the take of
marine mammals that may occur incidental to the activity; NMFS does not
permit the activity itself. However, the National Science Foundation,
as the funder of the survey, has been in communication with the New
Zealand Department of Conservation (NZDOC) regarding the survey, and
recommendations from the NZDOC have been incorporated in the IHA. For
instance, the power down waiver for bottlenose dolphins has been
removed from the IHA based on input received from the NZDOC (see the
section on Revisions to the IHA That Have Occurred Since the Proposed
IHA, below, for details). The comment also stated that lack of
communication with indigenous groups represents a breach of the Treaty
of Waitangi; however, the United States is not a Party to the Treaty of
Waitangi.
Comment 14: A member of the general public expressed concern
regarding potential impacts to marine mammals, including impacts to
mother-calf pairs, South Island Hector's dolphins, southern right
whales, blue whales, killer whales, sperm whales and beaked whales. The
commenter also expressed concern that tourism companies could be hurt
financially by the planned surveys
NMFS Response: The commenter expressed concern that the timing of
the planned surveys overlaps with calving season for delphinids and
that noise from the planned surveys could interfere with mother-calf
communication. The commenter did not provide any detailed or
substantive information or references to support this statement or
change our analyses. We recognize that restricted communication as a
result of increased noise from seismic surveys may be of concern, which
is why we have incorporated mitigation measures to minimize the
potential for this to occur. For instance, the IHA requires that the
airgun array be shut down upon observation of a large whale with calf
at any distance; additionally, the airgun array would be powered down
to a single 40 in\3\ airgun if any delphinids (other than those that
approach the vessel (i.e., bow ride)) are detected within 500 m of the
array. We have determined these measures ensure the least practicable
impact on the species potentially affected. The commenter expressed
concern regarding potential impacts to blue whales, killer whales,
sperm whales and other deep-diving whales. However, the comments
specific to blue whales, killer whales, sperm whales and other deep-
diving whales did not include any supporting information nor did they
recommend any specific action. NMFS believes the mitigation and
monitoring measures incorporated in the IHA, including measures
specific to sperm whales and other deep diving cetaceans, ensure the
least practicable impact on the species potentially affected (see the
Mitigation section, below).
The commenter also expressed concern regarding South Island
Hector's dolphins, specifically the subpopulation that resides in Te
Waewae Bay, noting that they exhibit high site fidelity and that the
survey will coincide with Hector's dolphin calving season. We agree
with the concerns raised by this comment, especially given the
proximity of the planned track lines of the South Island 2-D survey to
Te Waewae Bay (see Figure 2 in the IHA application). In response to
this concern, we have incorporated a mitigation measure that would
require shutdown of the array upon visual detection of South Island
Hector's dolphins at any distance. Based on this comment, we have also
added a mitigation measure requiring shutdown of the array upon
acoustic detection of a Hector's dolphin during North and South Island
surveys, if the acoustic detection can be definitively identified as a
Hector's dolphin. More information is provided below in the section on
Revisions to the IHA That Have Occurred Since the Proposed IHA.
Regarding the concern that tourism companies could be impacted
financially by the planned surveys, this statement was not supported by
any information and we cannot speculate as to any potential effects to
tourism companies as a result of L-DEO's survey. NMFS also does not
have any authority under the MMPA to restrict activities based on
potential impacts to tourism, as we do not authorize the activity
itself, as described above.
Comment 15: A member of the general public expressed concern that
the abundances for marine mammals provided in Table 2 in the Notice of
the Proposed IHA (82 FR 45116; September 27, 2017) do not reflect
abundance estimates for those marine mammals specifically around New
Zealand because they incorporate population estimates from the entire
Southern Hemisphere. The comment asserted that many of the marine
mammal species have unique and important subpopulations. The commenter
specifically recommended that the abundance estimates for southern
right whale and killer whale be revised.
NMFS Response: The commenter did not suggest specific revisions to
abundance estimates, with the exception of southern right whale and
killer whale. With respect to southern right whale and killer whale the
commenter did not provide specific information to support revisions to
our abundance estimates for those species. For southern right whales,
the commenter referenced an estimated abundance of 200. The source for
this estimate was the Web site of a New Zealand based non-governmental
organization; however, this Web site does not cite any literature to
support this estimate, therefore we have no way
[[Page 56126]]
to verify the accuracy of this figure or revise our abundance estimate
based on it. For killer whale abundance, the commenter referenced an
estimated abundance of 150-200 individuals. The source for this
estimate is a NZDOC Web site; however, this Web site does not cite any
literature to support this estimate, therefore we have no way to verify
the accuracy of this figure or revise our abundance estimate based on
it. The commenter did not provide any specific recommendations
regarding revisions to abundance estimates for any other species. The
commenter refers to marine mammals abundances described in Baker et al.
(2016); however, that document does not provide abundance estimates for
specific marine mammal species.
With regard to the abundance estimates for the other species in
Table 2, we made our findings about the applicable management units and
abundance estimates for those species based on the best available
information.
Comment 16: A member of the general public expressed concerns with
and offered suggestions about some of the mitigation measures. Specific
concerns or suggestions raised by the commenter were related to:
Mitigation measures for surveys during nighttime and low visibility;
the number and location of PSOs relative to the survey vessel;
verification of sound propagation modeling; size of exclusion zones;
use of power downs; mitigation for the multibeam echosounder (MBES) and
sub-bottom profiler (SBP); and shutdown requirements for Hector's
dolphins.
NMFS Response: The commenter expressed concern that mitigation
measures for surveys during nighttime and low visibility conditions
were limited to use of PAM. However, the IHA also requires that L-DEO
must provide a night-vision device suited for the marine environment
for use during nighttime ramp-up pre-clearance, which must include
automatic brightness and gain control, bright light protection,
infrared illumination, and optics suited for low-light situations. We
have determined that the mitigation measures specific to nighttime and
low visibility conditions ensure the least practicable impact on
species potentially affected.
The commenter expressed concern that the number of required PSOs is
not sufficient, and suggested observers be deployed on other vessels in
addition to the Langseth. However, we believe that mitigation and
monitoring measures required in the IHA can be adequately performed by
the number of PSOs required in the IHA, and that this has been
demonstrated through numerous monitoring reports submitted for past
IHAs for similar activities (i.e., marine geophysical surveys conducted
on the Langseth) which have used the same number of PSOs and the same
PSO staffing configurations as that required in this IHA. We believe
the number and location of PSOs required in the IHA ensure the least
practicable impact on species potentially affected.
The commenter expressed concern that sound propagation should be
verified in the field to ensure accuracy of the sound propagation
models. The commenter expressed that this would be of particular
concern in regards to the South Island Hector's dolphin subpopulation
that has site fidelity to Te Waewae Bay. As described above, NMFS
believes that L-DEO's current modeling approach represents the best
available information for NMFS to reach determinations for this IHA. We
refer the reader to the response to Comment 1, above, for a more
detailed discussion of L-DEO's acoustic modeling methodology. In
addition, as described above, results of acoustic modeling represent
just one component of the analysis during the MMPA authorization
process, as NMFS also takes into consideration other factors associated
with the activity and, as described herein, our determination of the
appropriate distance for mitigation zones is not based on acoustic
modeling. With respect to the use of sound source verification to
verify the distances to isopleths that coincide with harassment
thresholds for Hector's dolphins, we have incorporated a requirement in
the IHA that the array must be shut down upon visual or acoustic
detection of Hector's dolphins at any distance, as described below.
The commenter expressed concern about the 500 m exclusion zone and
recommended that the exclusion zone should be extended to between 1-1.5
km for all species of marine mammals detected visually and/or
acoustically, and referred to more conservative zones required by the
Code for some marine mammals. As described in the Federal Register
Notice of the Proposed IHA (82 FR 45116; September 27, 2017), our use
of 500 m as the EZ is based on a reasonable combination of factors.
This zone is expected to contain all potential auditory injury for all
marine mammals (high-frequency, mid-frequency and low-frequency
cetacean functional hearing groups and otariid and phocid pinnipeds) as
assessed against peak pressure thresholds (NMFS, 2016) (Tables 7, 8,
9). It is also expected to contain all potential auditory injury for
high-frequency and mid-frequency cetaceans as well as otariid and
phocid pinnipeds as assessed against SELcum thresholds
(NMFS, 2016) (Tables 7, 8, 9). Additionally, the 500 m EZ is expected
to minimize the likelihood that marine mammals will be exposed to
levels likely to result in more severe behavioral responses. It has
also proven to be practicable through past implementation in seismic
surveys conducted for the oil and gas industry. A practicable criterion
such as the proposed 500 m EZ 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. With
respect to the Code, as described above, NMFS does not have the
statutory authority to require L-DEO to abide by the requirements of
the Code outside a finding that the Code represents mitigation
necessary to effect the least practicable impact on the affected marine
mammal species or stocks, which is not the case here. However, we
encourage L-DEO to comply with the provisions of the Code to the extent
possible.
The commenter expressed concern that the use of the single 40 in\3\
airgun during power downs adds more sound to the marine environment,
though this comment appears to be based on the mistaken impression that
the single airgun may be used ``continuously.'' We note that the use of
the single 40 in\3\ airgun during power downs is, in fact, permitted
for no more than 30 minutes at any time (as described in greater detail
in the Mitigation section below). The comment did not cite any
substantive information regarding power downs or make any
recommendations regarding power downs, therefore we do not further
revise the requirements specific to power downs in response to this
comment.
The commenter expressed concern with the use of the MBES and SBP,
citing a report on a mass stranding of melon-headed whales on the
Madagascar coast in 2008 that was attributed to use of a MBES (Southall
et al., 2013). The commenter also requested that NMFS require that the
MBES be shut down in instances when mitigation measures require
shutdown of the airgun array.
A Kongsberg EM 122 MBES would be operated continuously during the
proposed surveys, but not during transit to and from the survey areas.
Due to the lower source level of the MBES relative to the Langseth's
airgun array, sounds from the MBES are expected to be effectively
subsumed by the sounds from the airgun array when both sources are
operational. Thus, NMFS has
[[Page 56127]]
determined that any marine mammal potentially exposed to sounds from
the MBES would already have been exposed to sounds from the airgun
array, which are expected to propagate further in the water, when both
sources are operational. During periods when the airguns are inactive
and the MBES is operational, NMFS has determined that, given the
movement and speed of the vessel and the intermittent and narrow
downward-directed nature of the sounds emitted by the MBES (each ping
emitted by the MBES consists of eight (in water >1,000 m deep) or four
(<1,000 m) successive fan-shaped transmissions, each ensonifying a
sector that extends 1[deg] fore-aft), the MBES would result in no more
than one or two brief ping exposures to any individual marine mammal,
if any exposure were to occur.
Regarding the 2008 mass stranding of melon-headed whales in
Madagascar, it should be noted that the report to which the commenter
refers states that while the MBES was determined as the most likely
cause of the stranding event, there was no unequivocal and easily
identifiable single cause of the event, such as those that have been
implicated in previous marine mammal mortalities (e.g., entanglement,
vessel strike, identified disease) or mass stranding events (e.g.,
weather, extreme tidal events, predator presence, anthropogenic noise)
(Southall et al., 2013). The report also notes that the 2008 mass
stranding event in Madagascar was the first known such marine mammal
mass stranding event closely associated with relatively high-frequency
mapping sonar systems such as MBES and that similar MBES systems are in
fact commonly used in hydrographic surveys around the world over large
areas without such events being previously documented (Southall et al.,
2013). The report found that in the case of the 2008 mass stranding
event, environmental, social, or some other confluence of factors
(e.g., shoreward-directed surface currents and elevated chlorophyll
levels in the area preceding the stranding) may have meant that that
particular group of whales was oriented relative to the directional
movement of the survey vessel (the vessel moved in a directed manner
down the shelf-break; Southall et al., 2013, Figure 2) in such a way
that an avoidance response caused animals to move into an unfamiliar
and unsafe out-of-habitat area (Southall et al., 2013). NMFS is not
aware of any marine mammal stranding events that have been documented
as a result of exposure to sounds from MBES since the Madagascar mass
stranding event in 2008. Based on the best available information, we do
not believe the use of the MBES aboard the Langseth will result in
marine mammal strandings.
The commenter expressed concern that a shutdown requirement upon
any observation of Hector[acute]s dolphins at any distance, including
upon acoustic detection, is warranted. As described above, based on the
best available information, NMFS agrees this measure is warranted, and
has incorporated these requirements in the IHA. See the section on
Mitigation and the section on Revisions to the IHA That Have Occurred
Since the Proposed IHA, below, for details.
In summary, we have determined the mitigation measures contained in
the IHA ensure the least practicable impact on marine mammal species
potentially affected.
Comment 17: A member of the general public expressed that L-DEO
should employ alternative research technologies, including Vibroseis
and AquaVib, rather than airguns to perform the planned marine
geophysical surveys.
NMFS Response: At this point in time, the alternative technologies
identified by the commenter are not commercially viable or appropriate
to meet the needs of the planned surveys. With respect to Vibroseis,
there is no commercially available marine vibrator system that can be
used for the planned surveys. The AquaVib is a modified version of a
land seismic vibrator system that is capable of being placed in very
shallow water (i.e., a few meters) and in transition zone environments
(i.e., marshes, etc.); however the AquaVib would not be suitable for L-
DEO's planned surveys. As suggested by the commenter, NMFS has
requested the National Science Foundation to continue to review and
consider alternative technologies to support future marine geophysical
research.
Comment 18: A member of the general public stated that L-DEO should
agree to pay for any necropsies of marine mammals that strand around
the entire coastline of New Zealand during and after the survey.
NMFS Response: NMFS does not anticipate that the survey will result
in strandings of marine mammals. We also do not have the authority to
require applicants to fund marine mammal necropsies. However, should
any stranded animals be observed during the surveys, we have included
reporting measures to ensure L-DEO promptly notifies NMFS and the NZDOC
(see the section on Reporting, below).
In addition to the comments above, NMFS received comments from the
MSROC and an additional comment from the general public. The comment
letter from the MSROC affirmed that there is significant support from
the MSROC for the IHA to be issued for the proposed surveys and for the
surveys to be conducted. A private citizen expressed concern that
animals should not be harmed in the process of surveying or studying
them. NMFS considered this comment, however, it did not contain any
substantive information regarding the potential for the proposed
surveys to harm marine mammals.
Revisions to the IHA That Have Occurred Since the Proposed IHA
Based on public comments and a recalculation of the take estimates
in the proposed IHA, we have made revisions to the IHA since we
published the notice of the proposed IHA in the Federal Register (82 FR
45116; September 27, 2017). Those revisions are described below.
Revisions to the take estimates--Take estimates in the final IHA
have been revised slightly since we published the notice of the
proposed IHA in the Federal Register (82 FR 45116; September 27, 2017),
due to a math error in calculating the 25 percent correction factor for
uncertainty in density estimates applied to the overall take estimate.
This has resulted in higher take estimates in some cases, and lower
take estimates in some cases, in comparison to the take estimates
described in the notice of the proposed IHA. Revised take estimates are
shown in Tables 10, 11, 12 and 13. These revisions have not impacted
our preliminary determinations.
Shutdown requirement upon visual detection of an aggregation of
large whales at any distance--We have added a mitigation measure that
requires that the airgun array be shut down upon visual detection of an
aggregation (i.e., six or more animals) of large whales of any species
(i.e., sperm whale or any baleen whale) at any distance. This measure
is discussed in greater detail in the Mitigation section, below.
Shutdown requirement upon visual detection of South Island Hector's
dolphins--We have added a mitigation measure that requires that the
airgun array be shut down upon visual detection of a Hector's dolphin
during the South Island survey. Hector's dolphins have relatively small
home ranges and high site fidelity; a survey in 2002 found that the
majority of Hector's dolphins ranged less than 60 km (Brager et al.,
2002); along-shore home range is typically less than 50 km (Oremus et
al., 2012). There are at least three,
[[Page 56128]]
genetically distinct, regional populations of South Island Hector's
dolphin (Dawson et al. 2004); a genetically distinct and localized
population occurs in Te Waewae Bay (Mackenzie and Clement, 2014)). Due
to the limited range and high site fidelity of the population of
Hector's dolphin that occurs in Te Waewae Bay and the proximity of the
planned South Island 2-D survey with Te Waewae Bay (see Figure 2 in the
IHA application), NMFS has determined that shutdown of the array upon
visual detection of Hector's dolphins during the South Island 2-D
survey is warranted.
Shutdown requirement upon acoustic detection of Hector's dolphins,
beaked whales, sperm whales, or Kogia spp.--We have added a mitigation
measure that requires that the airgun array be shut down upon acoustic
detection of Hector's dolphins, beaked whales, sperm whales, or Kogia
spp. (with an exception for sperm whales only, if the acoustic
detection can be localized and it is determined the sperm whale is
outside the 500 m EZ). The requirement to shut down the airgun array
upon visual detection of a beaked whale or Kogia spp. at any distance
was included in the Federal Register notice of the proposed IHA (82 FR
45116; September 27, 2017) in recognition of the fact that these
species are behaviorally sensitive deep divers and it is possible that
disturbance could provoke a severe behavioral response leading to
injury (e.g., Wursig et al., 1998; Cox et al., 2006). The requirement
to shut down the airgun array upon visual detection of a Hector's
dolphin at any distance was included in the Federal Register notice of
the proposed IHA (82 FR 45116; September 27, 2017), specifically for
the planned North Island surveys; we have since added the requirement
that the array must be shut down upon observation of a Hector's
dolphin, at any distance, during the South Island survey (as described
above). The intent behind the requirement to shut down upon acoustic
detection is the same as that behind the requirement to shut down upon
visual detection. As discussed above, shutdown upon visual detection of
sperm whales at any distance is not required in the IHA (the reasoning
for this decision is described in further detail in the Mitigation
section, below). However, we have determined that meaningful measures
are warranted to minimize potential disruption of foraging behavior in
sperm whales. This measure (i.e., shutdown upon acoustic detection of
beaked whales, sperm whales, or Kogia spp., with an exception for sperm
whales only, if the acoustic detection can be localized and it is
determined the sperm whale is outside the 500 m EZ) is discussed in
greater detail in the Mitigation section, below.
Revision to power down waiver for certain delphinids--In the
Federal Register notice of the proposed IHA (82 FR 45116; September 27,
2017), NMFS proposed a waiver to the requirement to power down the
array upon marine mammals observed within or approaching the 500 m
exclusion zone that would apply specifically to cetaceans of the genera
Tursiops, Delphinus and Lissodelphis that approach the vessel (e.g.,
bow riding). We have revised this waiver to the requirement to power
down the array such that it applies to all small dolphins except
spectacled porpoise and bottlenose, hourglass, and Hector's dolphins.
We have revised the species for which the power down waiver applies
because we had previously mistakenly excluded all dolphins in the
genera Lagenorhynchus from the power down waiver, based on a concern
(which we still hold) that cetaceans considered to be in the high
frequency functional hearing group would be more sensitive to airgun
sounds; however, as dusky dolphins (Lagenorhynchus obscurus) are in
fact considered to be in the mid frequency functional hearing group, we
believe the power down waiver should apply to dusky dolphins.
Additionally, we have removed cetaceans of the genera Tursiops (i.e.,
bottlenose dolphins) from the power down waiver in response to concerns
expressed by the NZDOC, as bottlenose dolphins are listed as a species
of concern in New Zealand and are particularly susceptible to impacts
from human activities due to their coastal nature. Therefore the power
down waiver will not apply for bottlenose dolphins. Effectively, the
species which are included in the power down waiver are: short-beaked
common dolphin (Delphinus delphis), dusky dolphin (Lagenorhynchus
obscurus) and southern right whale dolphin (Lissodelphis peronii).
Finally, we specified in the proposed IHA that the waiver would only
apply if the animals were traveling, including approaching the vessel.
However, we have removed that requirement from the IHA, based on an
acknowledgement that it would have required subjective on-the-spot
decision-making on the part of PSOs, which may have resulted in
differential implementation as informed by individual PSOs' experience,
background, and/or training.
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 southwest Pacific Ocean off New Zealand and summarizes information
related to the population, including regulatory status under the MMPA
and ESA. The populations of marine mammals considered in this document
do not occur within the U.S. EEZ and are therefore not assigned to
stocks and are not assessed in NMFS' Stock Assessment Reports
(www.nmfs.noaa.gov/pr/sars/). As such, information on potential
biological removal (PBR; defined by the MMPA as the maximum number of
animals, not including natural mortalities, that may be removed from a
marine mammal stock while allowing that stock to reach or maintain its
optimum sustainable population) and on annual levels of serious injury
and mortality from anthropogenic sources are not available for these
marine mammal populations.
In addition to the marine mammal species known to occur in planned
survey areas, there are 16 species of marine mammals with ranges that
are known to potentially occur in the waters of the planned survey
areas, but they are categorized as ``vagrant'' under the New Zealand
Threat Classification System (Baker et al., 2016). These species are:
The ginkgo-toothed whale (Mesoplodon ginkgodens); pygmy beaked whale
(M. peruvianus); dwarf sperm whale (Kogia sima); pygmy killer whale
(Feresa attenuata); melon-headed whale (Peponocephala electra); Risso's
dolphin (Grampus griseus); Fraser's dolphin (Lagenodelphis hosei),
pantropical spotted dolphin (Stenella attenuata); striped dolphin (S.
coeruleoalba); rough-toothed dolphin (Steno bredanensis); Antarctic fur
seal (Arctocephalus gazelle); Subantarctic fur seal (A. tropicalis);
leopard seal (Hydrurga leptonyx); Weddell seal (Leptonychotes
weddellii); crabeater seal (Lobodon carcinophagus); and Ross seal
(Ommatophoca rossi). Except for Risso's
[[Page 56129]]
dolphin and leopard seal, for which there have been several sightings
and strandings reported in New Zealand (Clement 2010; Torres 2012;
Berkenbusch et al. 2013; NZDOC 2017), the other ``vagrant'' species
listed above are not expected to occur in the planned survey areas and
are therefore not considered further in this document.
Marine mammal abundance estimates presented in this document
represent the total number of individuals estimated within a particular
study or survey area. All values presented in Table 2 are the most
recent available at the time of publication.
Table 2--Marine Mammals That Could Occur in the Planned Survey Areas
----------------------------------------------------------------------------------------------------------------
ESA/MMPA status; Population
Common name Scientific name Stock strategic (Y/N) \1\ abundance \2\
----------------------------------------------------------------------------------------------------------------
Order Cetartiodactyla--Cetacea--Superfamily Mysticeti (baleen whales)
----------------------------------------------------------------------------------------------------------------
Family Balaenidae
----------------------------------------------------------------------------------------------------------------
Southern right whale.............. Eubalaena australis.. N/A E/D;Y \3\ 12,000
----------------------------------------------------------------------------------------------------------------
Family Balaenopteridae (rorquals)
----------------------------------------------------------------------------------------------------------------
Humpback whale.................... Megaptera N/A -/-; N \3\ 42,000
novaeangliae.
Bryde's whale..................... Balaenoptera edeni... N/A -/-; N \4\ 48,109
Common minke whale................ Balaenoptera N/A -/-; N \5\ \6\ 750,000
acutorostrata.
Antarctic minke whale............. Balaenoptera N/A -/-; N \5\ \6\ 750,000
bonaerensis.
Sei whale......................... Balaenoptera borealis N/A E/D;Y \5\ 10,000
Fin whale......................... Balaenoptera physalus N/A E/D;Y \5\ 15,000
Blue whale........................ Balaenoptera musculus N/A E/D;Y \3\ \5\ 3,800
----------------------------------------------------------------------------------------------------------------
Family Cetotheriidae
----------------------------------------------------------------------------------------------------------------
Pygmy right whale................. Caperea marginata.... N/A -/-; N N/A
----------------------------------------------------------------------------------------------------------------
Superfamily Odontoceti (toothed whales, dolphins, and porpoises)
----------------------------------------------------------------------------------------------------------------
Family Physeteridae
----------------------------------------------------------------------------------------------------------------
Sperm whale....................... Physeter N/A E/D;Y \5\ 30,000
macrocephalus.
----------------------------------------------------------------------------------------------------------------
Family Kogiidae
----------------------------------------------------------------------------------------------------------------
Pygmy sperm whale................. Kogia breviceps...... N/A -/-; N N/A
----------------------------------------------------------------------------------------------------------------
Family Ziphiidae (beaked whales)
----------------------------------------------------------------------------------------------------------------
Cuvier's beaked whale............. Ziphius cavirostris.. N/A -/-; N \5\ \7\ 600,000
Arnoux's beaked whale............. Berardius arnuxii.... N/A -/-; N \5\ \7\ 600,000
Shepherd's beaked whale........... Tasmacetus shepherdi. N/A -/-; N \5\ \7\ 600,000
Hector's beaked whale............. Mesoplodon hectori... N/A -/-; N \5\ \7\ 600,000
True's beaked whale............... Mesoplodon mirus..... N/A -/-; N N/A
Southern bottlenose whale......... Hyperoodon planifrons N/A -/-; N \5\ \7\ 600,000
Gray's beaked whale............... Mesoplodon grayi..... N/A -/-; N \5\ \7\ 600,000
Andrew's beaked whale............. Mesoplodon bowdoini.. N/A -/-; N \5\ \7\ 600,000
Strap-toothed beaked whale........ Mesoplodon layardii.. N/A -/-; N \5\ \7\ 600,000
Blainville's beaked whale......... Mesoplodon N/A -/-; N \5\ \7\ 600,000
densirostris.
Spade-toothed beaked whale........ Mesoplodon traversii. N/A -/-; N \5\ \7\ 600,000
----------------------------------------------------------------------------------------------------------------
Family Delphinidae
----------------------------------------------------------------------------------------------------------------
Bottlenose dolphin................ Tursiops truncatus... N/A -/-; N N/A
Short-beaked common dolphin....... Delphinus delphis.... N/A -/-; N N/A
Dusky dolphin..................... Lagenorhynchus N/A -/-; N \8\ 12,000-
obscurus. 20,000
Hourglass dolphin................. Lagenorhynchus N/A -/-; N \5\ 150,000
cruciger.
Southern right whale dolphin...... Lissodelphis peronii. N/A -/-; N N/A
Risso's dolphin................... Grampus griseus...... N/A -/-; N N/A
South Island Hector's dolphin..... Cephalorhynchus N/A T/D;Y \9\ 14,849
hectori hectori.
Maui dolphin...................... Cephalorhynchus N/A E/D;Y \10\ 63
hectori maui.
False killer whale................ Pseudorca crassidens. N/A -/-; N N/A
Killer whale...................... Orcinus orca......... N/A -/-; N \5\ 80,000
Long-finned pilot whale........... Globicephala melas... N/A -/-; N \5\ 200,000
Short-finned pilot whale.......... Globicephala N/A -/-; N N/A
macrorhynchus.
----------------------------------------------------------------------------------------------------------------
Family Phocoenidae (porpoises)
----------------------------------------------------------------------------------------------------------------
Spectacled porpoise............... Phocoena dioptrica... N/A -/-; N N/A
----------------------------------------------------------------------------------------------------------------
[[Page 56130]]
Order Carnivora--Superfamily Pinnipedia
----------------------------------------------------------------------------------------------------------------
Family Otariidae (eared seals and sea lions)
----------------------------------------------------------------------------------------------------------------
New Zealand fur seal.............. Arctocephalus N/A -/-; N \8\ 200,000
forsteri.
New Zealand sea lion.............. Phocarctos hookeri... N/A -/-; N \11\ 9,880
----------------------------------------------------------------------------------------------------------------
Family Phocidae (earless seals)
----------------------------------------------------------------------------------------------------------------
Leopard seal...................... Hydrurga leptonyx.... N/A -/-; N \8\ 222,000
Southern elephant seal............ Mirounga leonina..... N/A -/-; N \8\ 607,000
----------------------------------------------------------------------------------------------------------------
N/A = Not available or not assessed.
\1\ Endangered Species Act (ESA) status: Endangered (E), Threatened (T)/MMPA status: Depleted (D). A dash (-)
indicates that the species is not listed under the ESA or designated as depleted under the MMPA. Under the
MMPA, a strategic stock is one for which the level of direct human-caused mortality exceeds PBR or which is
determined to be declining and likely to be listed under the ESA within the foreseeable future. Any species or
stock listed under the ESA is automatically designated under the MMPA as depleted and as a strategic stock.
\2\ Abundance for the Southern Hemisphere or Antarctic unless otherwise noted.
\3\ IWC (2016).
\4\ IWC (1981).
\5\ Boyd (2002).
\6\ Dwarf and Antarctic minke whales combined.
\7\ All Antarctic beaked whales combined.
\8\ Estimate for New Zealand; NZDOC 2017.
\9\ Estimate for New Zealand; MacKenzie and Clement 2016.
\10\ Estimate for New Zealand; Baker et al. (2016).
\11\ Geschke and Chilvers (2009).
All species that could potentially occur in the planned survey
areas are included in table 2. However, of the species described in
Table 2, the temporal and/or spatial occurrence of one subspecies, the
Maui dolphin (also known as the North Island Hector's dolphin), is such
that take is not expected to occur as a result of the surveys. The Maui
dolphin is one of two subspecies of Hector's dolphin (the other being
the South Island Hector's dolphin), both of which are endemic to New
Zealand. The Maui dolphin has been demonstrated to be genetically
distinct from the South Island subspecies of Hector's dolphin based on
studies of mitochondrial and nuclear DNA (Pichler et al. 1998). It is
currently considered one of the rarest dolphins in the world with a
population size estimated at just 55-63 individuals (Hamner et al.
2014; Baker et al. 2016). Historically, Hector's dolphins are thought
to have ranged along almost the entire coastlines of both the North and
South Islands of New Zealand, though their present range is
substantially smaller (Pichler 2002). The range of the Maui dolphin in
particular has undergone a marked reduction (Dawson et al. 2001;
Slooten et al. 2005), with the subspecies now restricted to the
northwest coast of the North Island, between Maunganui Bluff in the
north and Whanganui in the south (Currey et al. 2012). Occasional
sightings and strandings have also been reported from areas further
south along the west coast as well as possible sightings in other areas
such as Hawke's Bay on the east coast of North Island (Baker 1978,
Russell 1999, Ferreira and Roberts 2003, Slooten et al. 2005, DuFresne
2010, Berkenbusch et al. 2013; Torres et al. 2013; Pati[ntilde]o-
P[eacute]rez 2015; NZDOC 2017) though it is unclear whether those
individuals may have originated from the South Island Hector's dolphin
populations. A 2016 NMFS Draft Status Review Report concluded the Maui
dolphin is facing a high risk of extinction as a result of small
population size, reduced genetic diversity, low theoretical population
growth rates, evidence of continued population decline, and the ongoing
threats of fisheries bycatch, disease, mining and seismic disturbances
(Manning and Grantz 2016). Due to its extremely low population size and
the fact that the subspecies is not expected to occur in the planned
survey areas off the North Island, take of Maui dolphins is not
expected to occur as a result of L-DEO's activities. Therefore the Maui
dolphin is not discussed further beyond the explanation provided here.
We have reviewed L-DEO's species descriptions, including life
history information, distribution, regional distribution, diving
behavior, and acoustics and hearing, for accuracy and completeness. We
refer the reader to Section 4 of L-DEO's IHA application, rather than
reprinting the information here. A detailed description of the species
likely to be affected by L-DEO's survey, including brief introductions
to the species and relevant stocks as well as available information
regarding population trends and threats, and information regarding
local occurrence, were provided in the Federal Register notice for the
proposed IHA (82 FR 45116; September 27, 2017). Since that time, we are
not aware of any changes in the status of these species and stocks;
therefore, detailed descriptions are not provided here. Please refer to
that Federal Register notice for these descriptions. Please also refer
to NMFS' Web site (www.nmfs.noaa.gov/pr/species/mammals/) for
generalized species accounts.
Potential Effects of Specified Activities on Marine Mammals and Their
Habitat
The effects of underwater noise from marine geophysical survey
activities have the potential to result in behavioral harassment and,
in a limited number of instances, auditory injury (PTS) of marine
mammals in the vicinity of the action area. The Federal Register notice
of proposed IHA (82 FR 45116; September 27, 2017) included a discussion
of the effects of anthropogenic noise on marine mammals and their
habitat, therefore that information is not repeated here; please refer
to that Federal Register notice for that information. No instances of
serious injury or mortality are
[[Page 56131]]
expected as a result of L-DEO's survey activities.
Estimated Take
This section provides an estimate of the number of incidental takes
authorized through the 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 are primarily 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., Kogia 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
mitigation and monitoring measures are expected to minimize the
severity of such taking to the extent practicable.
As described previously, no serious injury or mortality is
anticipated or authorized for this activity. Below we describe how the
take is estimated.
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 authorized.
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 micropascal ([mu]Pa) (rms) for
continuous sources (e.g. vibratory pile-driving, drilling) and above
160 dB re 1 [mu]Pa (rms) for non-explosive impulsive (e.g., seismic
airguns) or intermittent (e.g., scientific sonar) sources. L-DEO's
activity includes the use of impulsive seismic sources. 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 3 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, L-DEO's activity
includes the use of intermittent and impulsive seismic sources.
Table 3--Thresholds Identifying the Onset of Permanent Threshold Shift in Marine Mammals
----------------------------------------------------------------------------------------------------------------
PTS onset thresholds
Hearing group ----------------------------------------------------------------------
Impulsive * Non-impulsive
----------------------------------------------------------------------------------------------------------------
Low-Frequency (LF) Cetaceans............. Lpk,flat: 219 dB; LE,LF,24h: 199 dB.
LE,LF,24h: 183 dB.
Mid-Frequency (MF) Cetaceans............. Lpk,flat: 230 dB; LE,MF,24h: 198 dB.
LE,MF,24h: 185 dB.
High-Frequency (HF) Cetaceans............ Lpk,flat: 202 dB; LE,HF,24h: 173 dB.
LE,HF,24h: 155 dB.
Phocid Pinnipeds (PW) (Underwater)....... Lpk,flat: 218 dB; LE,PW,24h: 201 dB.
LE,PW,24h: 185 dB.
Otariid Pinnipeds (OW) (Underwater)...... Lpk,flat: 232 dB; LE,OW,24h: 219 dB.
LE,OW,24h: 203 dB.
----------------------------------------------------------------------------------------------------------------
Note: * Dual metric acoustic thresholds for impulsive sounds: Use whichever results in the largest isopleth for
calculating PTS onset. If a non-impulsive sound has the potential of exceeding the peak sound pressure level
thresholds associated with impulsive sounds, these thresholds should also be considered.
[[Page 56132]]
Note: Peak sound pressure (Lpk) has a reference value of 1 [mu]Pa, and cumulative sound exposure level (LE) has
a reference value of 1[mu]Pa2s. In this Table, thresholds are abbreviated to reflect American National
Standards Institute standards (ANSI 2013). However, peak sound pressure is defined by ANSI as incorporating
frequency weighting, which is not the intent for this Technical Guidance. Hence, the subscript ``flat'' is
being included to indicate peak sound pressure should be flat weighted or unweighted within the generalized
hearing range. The subscript associated with cumulative sound exposure level thresholds indicates the
designated marine mammal auditory weighting function (LF, MF, and HF cetaceans, and PW and OW pinnipeds) and
that the recommended accumulation period is 24 hours. The cumulative sound exposure level thresholds could be
exceeded in a multitude of ways (i.e., varying exposure levels and durations, duty cycle). When possible, it
is valuable for action proponents to indicate the conditions under which these acoustic thresholds will be
exceeded.
Ensonified Area
Here, we describe operational and environmental parameters of the
activity that will feed into estimating the area ensonified above the
relevant acoustic thresholds.
The survey entails use of a 36-airgun array with a total discharge
of 6,600 in\3\ at a tow depth of 9 m and an 18-airgun array with a
total discharge of 3,300 in\3\ at a tow depth of 7-9 m. Received sound
levels were predicted by L-DEO's model (Diebold et al., 2010) as a
function of distance from the 36-airgun array and 18-airgun array and
for a single 40-in\3\ airgun which would be used during power downs;
all models used a 9 m tow depth. This 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). In
addition, propagation measurements of pulses from the 36-airgun array
at a tow depth of 6 m have been reported in deep water (approximately
1600 m), intermediate water depth on the slope (approximately 600-1,100
m), and shallow water (approximately 50 m) in the Gulf of Mexico in
2007-2008 (Tolstoy et al. 2009; Diebold et al. 2010).
For deep and intermediate-water cases, L-DEO determined that the
field measurements cannot be used readily to derive zone of
ensonification, as at those sites the calibration hydrophone was
located at a roughly constant depth of 350-500 m, which may not
intersect all the SPL isopleths at their widest point from the sea
surface down to water depths of approximately 2,000 m (See Appendix H
in NSF-USGS 2011). At short ranges, where the direct arrivals dominate
and the effects of seafloor interactions are minimal, the data recorded
at the deep and slope sites are suitable for comparison with modeled
levels at the depth of the calibration hydrophone. At longer ranges,
the comparison with the mitigation model--constructed from the maximum
SPL through the entire water column at varying distances from the
airgun array--is the most relevant. Please see the IHA application for
further discussion of summarized results.
For deep water (>1,000 m), L-DEO used the deep-water radii obtained
from model results down to a maximum water depth of 2000 m. The radii
for intermediate water depths (100-1,000 m) were derived from the deep-
water ones by applying a correction factor (multiplication) of 1.5,
such that observed levels at very near offsets fall below the corrected
mitigation curve (See Fig. 16 in Appendix H of NSF-USGS, 2011). The
shallow-water radii were obtained by scaling the empirically derived
measurements from the Gulf of Mexico calibration survey to account for
the differences in tow depth between the calibration survey (6 m) and
the planned surveys (9 m). A simple scaling factor is calculated from
the ratios of the isopleths determined by the deep-water L-DEO model,
which are essentially a measure of the energy radiated by the source
array.
Measurements have not been reported for the single 40-in\3\ airgun.
L-DEO model results are used to determine the 160-dB (rms) radius for
the 40-in\3\ airgun at a 9 m tow depth in deep water (See LGL 2017,
Figure 6). For intermediate-water depths, a correction factor of 1.5
was applied to the deep-water model results. For shallow water, a
scaling of the field measurements obtained for the 36-airgun array was
used.
L-DEO's modeling methodology is described in greater detail in the
IHA application (LGL 2017) and we refer the reader to that document
rather than repeating it here. The estimated distances to the Level B
harassment isopleth for the Langseth's 36-airgun array, 18-airgun
array, and the single 40-in\3\ airgun are shown in Table 4.
Table 4--Predicted Radial Distances from R/V Langseth Seismic Source to
Isopleths Corresponding to Level B Harassment Threshold
------------------------------------------------------------------------
Predicted
distance to
Water depth threshold
Source and volume (m) (160 dB re
1 [mu]Pa)
\1\ (m)
------------------------------------------------------------------------
1 airgun, 40 in\3\............................ >1,000 388
100-1,000 582
<100 938
18 airguns, 3,300 in\3\....................... >1,000 3,562
100-1,000 5,343
<100 10,607
36 airguns, 6,600 in\3\....................... >1,000 5,629
100-1,000 8,444
<100 22,102
------------------------------------------------------------------------
\1\ Distances for depths >1,000 m are based on L-DEO model results.
Distance for depths 100-1,000 m are based on L-DEO model results with
a 1.5 x correction factor between deep and intermediate water depths.
Distances for depths <100 m are based on empirically derived
measurements in the Gulf of Mexico with scaling applied to account for
differences in tow depth.
Predicted distances to Level A harassment isopleths, which vary
based on marine mammal hearing groups, were calculated based on
modeling performed by L-DEO using the NUCLEUS software program and the
NMFS User Spreadsheet, described below. The updated acoustic thresholds
for impulsive sounds (e.g., airguns) contained in the Technical
Guidance were presented as dual metric acoustic thresholds using both
SELcum and peak sound pressure metrics (NMFS 2016). As dual
metrics, NMFS considers onset of PTS (Level A harassment) to have
occurred when either one of the two metrics is exceeded (i.e., metric
resulting in the largest isopleth). The SELcum metric
considers both level and duration of exposure, as well as auditory
weighting functions by marine mammal hearing group. In recognition of
the fact that the requirement to calculate Level A harassment
ensonified areas could be more technically challenging to predict due
to the duration component and the use of weighting functions in the new
SELcum thresholds, NMFS developed an optional User
Spreadsheet that includes tools to help predict a simple isopleth that
can be used in conjunction with marine mammal density or occurrence to
facilitate the estimation of take numbers.
The values for SELcum and peak SPL for the Langseth
airgun array were derived from calculating the modified farfield
signature (Table 5). The farfield
[[Page 56133]]
signature is often used as a theoretical representation of the source
level. To compute the farfield signature, the source level is estimated
at a large distance below the array (e.g., 9 km), and this level is
back projected mathematically to a notional distance of 1 m from the
array's geometrical center. However, when the source is an array of
multiple airguns separated in space, the source level from the
theoretical farfield signature is not necessarily the best measurement
of the source level that is physically achieved at the source (Tolstoy
et al. 2009). Near the source (at short ranges, distances <1 km), the
pulses of sound pressure from each individual airgun in the source
array do not stack constructively, as they do for the theoretical
farfield signature. The pulses from the different airguns spread out in
time such that the source levels observed or modeled are the result of
the summation of pulses from a few airguns, not the full array (Tolstoy
et al. 2009). At larger distances, away from the source array center,
sound pressure of all the airguns in the array stack coherently, but
not within one time sample, resulting in smaller source levels (a few
dB) than the source level derived from the farfield signature. Because
the farfield signature does not take into account the large array
effect near the source and is calculated as a point source, the
modified farfield signature is a more appropriate measure of the sound
source level for distributed sound sources, such as airgun arrays. L-
DEO used the acoustic modeling methodology as used for Level B takes
with a small grid step of 1 m in both the inline and depth directions.
The propagation modeling takes into account all airgun interactions at
short distances from the source, including interactions between
subarrays which are modeled using the NUCLEUS software to estimate the
notional signature and MATLAB software to calculate the pressure signal
at each mesh point of a grid.
Table 5--Modeled Source Levels Based on Modified Farfield Signature for the R/V Langseth 6,600 in \3\ Airgun
Array, 3,300 in\3\ Airgun Array, and Single 40 in\3\ Airgun
----------------------------------------------------------------------------------------------------------------
Phocid Otariid
Low frequency Mid frequency High frequency pinnipeds pinnipeds
cetaceans cetaceans cetaceans (underwater) (underwater)
(Lpk,flat: 219 (Lpk,flat: 230 (Lpk,flat: 202 (Lpk,flat: 218 (Lpk,flat: 232
dB; LE,LF,24h: dB; LE,MF,24h: dB; LE,HF,24h: dB; LE,HF,24h: dB; LE,HF,24h:
183 dB) 185 dB) 155 dB) 185 dB) 203 dB)
----------------------------------------------------------------------------------------------------------------
6,600 in\3\ airgun array (Peak 250.77 252.76 249.44 250.50 252.72
SPLflat).......................
6,600 in\3\ airgun array 232.75 232.67 232.83 232.67 231.07
(SELcum).......................
3,300 in\3\ airgun array (Peak 246.34 250.98 243.64 246.03 251.92
SPLflat).......................
3,300 in\3\ airgun array 226.22 226.13 226.75 226.13 226.89
(SELcum).......................
40 in\3\ airgun (Peak SPLflat).. 224.02 225.16 224.00 224.09 226.64
40 in\3\ airgun (SELcum)........ 202.33 202.35 203.12 202.35 202.61
----------------------------------------------------------------------------------------------------------------
In order to more realistically incorporate the Technical Guidance's
weighting functions over the seismic array's full acoustic band,
unweighted spectrum data for the Langseth's airgun array (modeled in 1
hertz (Hz) bands) was used to make adjustments (dB) to the unweighted
spectrum levels, by frequency, according to the weighting functions for
each relevant marine mammal hearing group. These adjusted/weighted
spectrum levels were then converted to pressures ([mu]Pa) in order to
integrate them over the entire broadband spectrum, resulting in
broadband weighted source levels by hearing group that could be
directly incorporated within the User Spreadsheet (i.e., to override
the Spreadsheet's more simple weighting factor adjustment). Using the
User Spreadsheet's ``safe distance'' methodology for mobile sources
(described by Sivle et al., 2014) with the hearing group-specific
weighted source levels, and inputs assuming spherical spreading
propagation and source velocities and shot intervals specific to each
of the three planned surveys (Table 1), potential radial distances to
auditory injury zones were then calculated for SELcum
thresholds.
Inputs to the User Spreadsheets in the form of estimated SLs are
shown in Table 5. User Spreadsheets used by L-DEO to estimate distances
to Level A harassment isopleths (SELcum) for the 36-airgun
array, 18-airgun array, and the single 40 in \3\ airgun for the South
Island 2-D survey, North Island 2-D survey, and North Island 3-D survey
are shown in Tables 3, 4, 7, 10, 11, and 12, of the IHA application
(LGL 2017). Outputs from the User Spreadsheets in the form of estimated
distances to Level A harassment isopleths for the South Island 2-D
survey, North Island 2-D survey, and North Island 3-D survey are shown
in Tables 6, 7 and 8, respectively. As described above, NMFS considers
onset of PTS (Level A harassment) to have occurred when either one of
the dual metrics (SELcum and Peak SPLflat) is
exceeded (i.e., metric resulting in the largest isopleth).
Table 6--Modeled Radial Distances (m) to Isopleths Corresponding to Level A Harassment Thresholds During North
Island 2-D Survey
----------------------------------------------------------------------------------------------------------------
Phocid Otariid
Low frequency Mid frequency High frequency pinnipeds pinnipeds
cetaceans cetaceans cetaceans (underwater) (underwater)
(Lpk,flat: 219 (Lpk,flat: 230 (Lpk,flat: 202 (Lpk,flat: 218 (Lpk,flat: 232
dB; LE,LF,24h: dB; LE,MF,24h: dB; LE,HF,24h: dB; LE,HF,24h: dB; LE,HF,24h:
183 dB) 185 dB) 155 dB) 185 dB) 203 dB)
----------------------------------------------------------------------------------------------------------------
6,600 in\3\ airgun array (Peak 38.8 13.8 229.2 42.2 10.9
SPLflat).......................
6,600 in\3\ airgun array 501.3 0 1.2 13.2 0
(SELcum).......................
40 in\3\ airgun (Peak SPLflat).. 1.8 0.6 12.6 2.0 0.5
40 in\3\ airgun (SELcum)........ 0.4 0 0 0 0
----------------------------------------------------------------------------------------------------------------
[[Page 56134]]
Table 7--Modeled Radial Distances (m) to Isopleths Corresponding to Level A Harassment Thresholds During North
Island 3-D Survey
----------------------------------------------------------------------------------------------------------------
Phocid Otariid
Low frequency Mid frequency High frequency Pinnipeds Pinnipeds
cetaceans cetaceans cetaceans (Underwater) (Underwater)
(Lpk,flat: 219 (Lpk,flat: 230 (Lpk,flat: 202 (Lpk,flat: 218 (Lpk,flat: 232
dB; LE,LF,24h: dB; LE,MF,24h: dB; LE,HF,24h: dB; LE,HF,24h: dB; LE,HF,24h:
183 dB) 185 dB) 155 dB) 185 dB) 203 dB)
----------------------------------------------------------------------------------------------------------------
3,300 in\3\ airgun array (Peak 23.3 11.2 119.0 25.2 9.9
SPLflat).......................
3,300 in\3\ airgun array 73.1 0 0.3 2.8 0
(SELcum).......................
40 in\3\ airgun (Peak SPLflat).. 1.8 0.6 12.6 2.0 0.5
40 in\3\ airgun (SELcum)........ 0.4 0 0 0 0
----------------------------------------------------------------------------------------------------------------
Table 8--Modeled Radial Distances (m) to Isopleths Corresponding to Level A Harassment Thresholds During South
Island 2-D Survey
----------------------------------------------------------------------------------------------------------------
Otariid
Low frequency Mid frequency High frequency Phocid Pinnipeds
cetaceans cetaceans cetaceans Pinnipeds (Underwater)
(Lpk,flat: 219 (Lpk,flat: 230 (Lpk,flat: 202 (Underwater) (Lpk,flat: 232
dB; LE,LF,24h: dB; LE,MF,24h: dB; LE,HF,24h: (Lpk,flat: 218 dB; LE,
183 dB) 185 dB) 155 dB) dB; LE,HF,24h: HF,24h: 203
185 dB) dB)
----------------------------------------------------------------------------------------------------------------
6,600 in\3\ airgun array (Peak 38.8 13.8 229.2 42.2 10.9
SPLflat).......................
6,600 in\3\ airgun array 376.0 0 0.9 9.9 0
(SELcum).......................
40 in\3\ airgun (Peak SPLflat).. 1.8 0.6 12.6 2.0 0.5
40 in\3\ airgun (SELcum)........ 0.3 0 0 0 0
----------------------------------------------------------------------------------------------------------------
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 3-D modeling methods are not
available, and NMFS continues to develop ways to quantitatively refine
these tools and will qualitatively address the output where
appropriate. For mobile sources, such as the planned seismic surveys,
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).
No systematic aircraft- or ship-based surveys have been conducted
for marine mammals in offshore waters of the South Pacific Ocean off
New Zealand that can be used to estimate species densities that we are
aware of, with the exception of Hector's dolphin surveys that have
occurred off the South Island. Densities for Hector's dolphins off the
South Island were estimated using averaged estimated summer densities
from the most southern stratum of an East Coast South Island survey
(Otago) and a West Coast South Island survey (Milford Sound), both in
three offshore strata categories (0-4 nautical miles (nm), 4-12 nm, and
12-20 nm; MacKenzie and Clement 2014, 2016). The estimated density for
Hector's dolphins for the South Island 2-D survey was based on the
proportion of that survey occurring in each offshore stratum.
For cetacean species other than Hector's dolphin, densities were
derived from data available for the Southern Ocean (Butterworth et al.
1994; Kasamatsu and Joyce 1995) (See Table 17 in the IHA application).
Butterworth et al. (1994) provided comparable data for sei, fin, blue,
and sperm whales extrapolated to latitudes 30-40[deg] S., 40-50[deg]
S., and 50-60[deg] S. based on Japanese scouting vessel data from 1965/
66-1977/78 and 1978/79-1987/88. Densities were calculated for these
species based on abundances and surface areas provided in Butterworth
et al. (1994) using the mean density for the more recent surveys (1978/
79-1987/88) and the 30-40[deg] S. and 40-50[deg] S. strata, because the
planned survey areas are between ~37[deg] S. and 50[deg] S. Densities
were corrected for mean trackline detection probability, g(0)
availability bias, using mean g(0) values provided for these species
during NMFS Southwest Fisheries Science Center ship-based surveys
between 1991-2014 (Barlow 2016). Data for the humpback whale was also
presented in Butterworth et al. (1994), but, based on the best
available information, it was determined that the density values
presented for humpback whales in Butterworth et al. (1994) were likely
lower than would be expected in the planned survey areas, thus the
density for humpback whales was ultimately calculated in the same way
as for the baleen whales for which density data was unavailable.
Kasamatsu and Joyce (1995) provided data for beaked whales, killer
whales, long-finned pilot whales, and hourglass dolphins, based on
surveys conducted as part of the International Whaling Commission/
International Decade of Cetacean Research--Southern Hemisphere Minke
Whale Assessment, started in 1978/79, and the Japanese sightings survey
program started in 1976/77. Densities for these species were calculated
based on abundances and surface areas provided in Kasamatsu and Joyce
(1995) for Antarctic Areas V EMN and VI WM, which represent the two
areas reported in Kasamatsu and Joyce (1995) that are nearest to the
planned South Island survey area. Densities were corrected for
availability bias using mean g(0) values provided by Kasamatsu and
Joyce (1995) for beaked whales, killer whales, and long-fined pilot
whales, and provided by Barlow (2016) for the Hourglass dolphin using
the mean g(0) calculated for unidentified dolphins during NMFS
[[Page 56135]]
Southwest Fisheries Science Center ship-based surveys between 1991-
2014.
For the remaining cetacean species, the relative abundances of
individual species expected to occur in the survey areas were estimated
within species groups. The relative abundances of these species were
estimated based on several factors, including information on marine
mammal observations from areas near the planned survey areas (e.g.,
monitoring reports from previous IHAs (NMFS, 2015); datasets of
opportunistic sightings (Torres et al., 2014); and analyses of observer
data from other marine geophysical surveys conducted in New Zealand
waters (Blue Planet, 2016)), information on latitudinal ranges and
group sizes of marine mammals in New Zealand waters (e.g., Jefferson et
al., 2015; NABIS, 2017; Perrin et al., 2009), and other information on
marine mammals in and near the planned survey areas (e.g., data on
marine mammal bycatch in New Zealand fisheries (Berkenbush et al.,
2013), data on marine mammal strandings (New Zealand Marine Mammal
Strandings and Sightings Database); and input from subject matter
experts (pers. comm., E. Slooten, Univ. of Otago, to H. Goldstein,
NMFS, April 11, 2015)).
For each species group (i.e., mysticetes), densities of species for
which data were available were averaged to get a mean density for the
group (e.g., densities of fin, sei, and blue whale were averaged to get
a mean density for mysticetes). Relative abundances of those species
were then averaged to get mean relative abundances (e.g., relative
abundance of fin, sei, and blue whale were averaged to get a mean
relative abundance for mysticetes). For the species for which density
data was unavailable, their relative abundance score was multiplied by
the mean density of their respective species group (i.e., relative
abundance of minke whale was multiplied by mean density for
mysticetes). The product was then divided by the mean relative
abundance of the species group to come up with a density estimate. The
fin, sei, and blue whale densities calculated from Butterworth et al.
(1994) were proportionally averaged and used to estimate the densities
of the remaining mysticetes. The sperm whale density calculated from
Butterworth et al. (1994) was used to estimate the density of the other
Physeteridae species, the pygmy sperm whale. The hourglass dolphin,
killer whale, and long-finned pilot whale densities calculated from
Kasamatsu and Joyce (1995) were proportionally averaged and used to
estimate the densities of the other Delphinidae for which density data
was not available. For beaked whales, the beaked whale density
calculated from Kasamatsu and Joyce (1995) was proportionally allocated
according to each beaked whale species' estimated relative abundance
value.
We are not aware of any information regarding at-sea densities of
pinnipeds off New Zealand. As such, a surrogate species (northern fur
seal) was used to estimate offshore pinniped densities for the planned
surveys. The at-sea density of northern fur seals reported in Bonnell
et al. (1992), based on systematic aerial surveys conducted in 1989-
1990 in offshore areas off the west coast of the U.S., was used to
estimate the numbers of pinnipeds that might be present off New
Zealand. The northern fur seal density reported in Bonnell et al.
(1992) was used as the New Zealand fur seal density. Densities for the
other three pinniped species expected to occur in the planned survey
areas were proportionally allocated relative to the value of the
density of the northern fur seal, in accordance to the estimated
relative abundance value of each of the other pinniped species.
NMFS acknowledges there is some uncertainty related to the
estimated density data and the assumptions used in their calculations.
Given the lack of available data on marine mammal density in the
planned survey areas, the approach used is based on the best available
data. In recognition of the uncertainties in the density data, we have
included an additional 25 percent contingency in take estimates to
account for the fact that density estimates used to estimate take may
be underestimates of actual densities of marine mammals in the survey
area. However, there is no information to suggest that the density
estimates used are in fact underestimates.
Take Calculation and Estimation
Here we describe how the information provided above is brought
together to produce a quantitative take estimate. In order to estimate
the number of marine mammals predicted to be exposed to sound levels
that would result in Level A harassment or Level B harassment, radial
distances from the airgun array to predicted isopleths corresponding to
the Level A harassment and Level B harassment thresholds are
calculated, as described above. Those radial distances are then used to
calculate the area(s) around the airgun array predicted to be
ensonified to sound levels that exceed the Level A harassment and Level
B harassment thresholds. The area estimated to be ensonified in a
single day of the survey is then calculated (Table 9), based on the
areas predicted to be ensonified around the array and the estimated
trackline distance traveled per day. This number is then multiplied by
the number of survey days (i.e., 35 days for the North Island 2-D
survey, 33 days for the North Island 3-D survey, and 22 days for the
South Island 2-D survey). The product is then multiplied by 1.25 to
account for an additional 25 percent contingency for potential
additional seismic operations (associated with turns, airgun testing,
and repeat coverage of any areas where initial data quality is sub-
standard, as proposed by L-DEO). This results in an estimate of the
total areas (km\2\) expected to be ensonified to the Level A harassment
and Level B harassment thresholds. For purposes of Level B take
calculations, areas estimated to be ensonified to Level A harassment
thresholds are subtracted from total areas estimated to be ensonified
to Level B harassment thresholds in order to avoid double counting the
animals taken (i.e., if an animal is taken by Level A harassment, it is
not also counted as taken by Level B harassment). The marine mammals
predicted to occur within these respective areas, based on estimated
densities, are assumed to be incidentally taken. The take estimates
were then multiplied by an additional 25 percent contingency in
acknowledgement of uncertainties in available density estimates, as
described above.
[[Page 56136]]
Table 9--Areas (km \2\) Estimated To Be Ensonified to Level A and Level B Harassment Thresholds per Day for Three Planned Seismic Surveys Off New
Zealand
--------------------------------------------------------------------------------------------------------------------------------------------------------
Level B Level A harassment threshold \1\
harassment -------------------------------------------------------------------------------
threshold
Survey ---------------- Low frequency Mid frequency High Otariid Phocid
All marine cetaceans cetaceans frequency pinnipeds pinnipeds
mammals cetaceans
--------------------------------------------------------------------------------------------------------------------------------------------------------
North Island 2-D Survey................................. 1,931.3 144.5 3.9 65.8 3.1 12.0
North Island 3-D Survey................................. 1,067.3 29.1 4.5 47.5 3.9 10.0
South Island 2-D Survey................................. 1,913.4 111.1 4.1 86.3 3.2 12.4
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ Level A ensonified areas are estimated based on the greater of the distances calculated to Level A isopleths using dual criteria (SELcum and
peakSPL).
Note: Estimated areas shown for single day do not include additional 50 percent contingency.
Factors including water depth, array configuration, and proportion
of each survey occurring within territorial seas (versus within the
EEZ) were also accounted for in estimates of ensonified areas. This was
accomplished by selecting a track line for a single day (for each of
the three planned surveys) that were representative of the entire
planned survey(s) and using that representative track line to calculate
daily ensonified areas. Daily track line distance was selected
depending on array configuration (i.e., 160 km per day for the planned
2-D surveys, 200 km per day for the planned 3-D survey). Representative
daily track lines were chosen to reflect the proportion of water depths
(i.e., less than 100 m, 100-1,000 m, and greater than 1,000 m) expected
to occur for that entire survey (Table 4) as distances to isopleths
corresponding to harassment vary depending on water depth (Table 4),
and water depths vary considerably within the planned survey areas
(Table 1). Representative track lines were also selected to reflect the
amount of effort in the New Zealand territorial sea (versus within the
New Zealand EEZ), for each of the three surveys, as L-DEO is not
subject to the requirements of the MMPA within the New Zealand
territorial sea. For example, for the North Island 2-D survey
approximately nine percent of survey effort would occur in the New
Zealand territorial sea (Table 1). Thus, representative track lines
that were chosen also had approximately 9 percent of survey effort in
territorial seas; the resultant ensonified areas within territorial
seas were excluded from take calculations.
Estimated takes for all marine mammal species are shown in Tables
10, 11, 12 and 13. As described above, we authorize the incidental
takes that are expected to occur as a result of the planned surveys
within the New Zealand EEZ but outside of the New Zealand territorial
sea.
Table 10--Numbers of Potential Incidental Take of Marine Mammals Authorized During L-DEO's North Island 2-D
Seismic Survey Off New Zealand
----------------------------------------------------------------------------------------------------------------
Total Level A
Density (#/ Level A takes Level B takes and Level B
Species 1,000 km\2\) authorized \1\ authorized \1\ takes
authorized \1\
----------------------------------------------------------------------------------------------------------------
Southern right whale............................ 0.24 2 23 25
Pygmy right whale............................... 0.10 1 9 10
Humpback whale.................................. 0.24 2 23 25
Bryde's whale................................... 0.14 1 14 15
Common minke whale.............................. 0.14 1 14 15
Antarctic minke whale........................... 0.14 1 14 15
Sei whale....................................... 0.14 1 14 15
Fin whale....................................... 0.25 2 24 26
Blue whale...................................... 0.04 0 4 4
Sperm whale..................................... 2.89 1 305 306
Cuvier's beaked whale........................... 2.62 1 276 277
Arnoux's beaked whale........................... 2.62 1 276 277
Southern bottlenose whale....................... 1.74 0 184 184
Shepard's beaked whale.......................... 1.74 0 184 184
Hector's beaked whale........................... 1.74 0 184 184
True's beaked whale............................. 0.87 0 92 92
Gray's beaked whale............................. 3.49 1 368 369
Andrew's beaked whale........................... 1.74 0 184 184
Strap-toothed whale............................. 2.62 1 276 277
Blainville's beaked whale....................... 0.87 0 92 92
Spade-toothed whale............................. 0.87 0 92 92
Bottlenose dolphin.............................. 5.12 1 540 541
Short-beaked common dolphin..................... 10.25 2 1080 1082
Dusky dolphin................................... 5.12 1 540 541
Southern right-whale dolphin.................... 3.07 1 324 325
Risso's dolphin................................. 2.05 0 216 216
False killer whale.............................. 3.07 1 324 325
Killer whale.................................... 1.91 0 202 202
Long-finned pilot whale......................... 8.28 2 872 874
Short-finned pilot whale........................ 4.10 1 432 433
[[Page 56137]]
Pygmy sperm whale............................... 1.74 6 177 183
Hourglass dolphin............................... 4.16 15 424 439
Hector's dolphin................................ 0 0 0 0
Spectacled porpoise............................. 0 0 0 0
New Zealand fur seal............................ 22.50 4 2373 2377
New Zealand sea lion............................ 0 0 0 0
Southern elephant seal.......................... 4.50 3 472 475
Leopard seal.................................... 2.25 1 236 237
----------------------------------------------------------------------------------------------------------------
\1\ Includes additional 25 percent contingency for potential additional survey operations and additional 25
percent contingency to account for uncertainties in density estimates.
Table 11--Numbers of Potential Incidental Take of Marine Mammals Authorized During L-DEO's North Island 3-D
Seismic Survey Off New Zealand
----------------------------------------------------------------------------------------------------------------
Total Level A
Density (#/ Level A takes Level B takes and Level B
Species 1,000 km\2\) authorized \1\ authorized \1\ takes
authorized \1\
----------------------------------------------------------------------------------------------------------------
Southern right whale............................ 0.24 0 13 13
Pygmy right whale............................... 0.10 0 5 5
Humpback whale.................................. 0.24 0 13 13
Bryde's whale................................... 0.14 0 8 8
Common minke whale.............................. 0.14 0 8 8
Antarctic minke whale........................... 0.14 0 8 8
Sei whale....................................... 0.14 0 8 8
Fin whale....................................... 0.25 0 13 13
Blue whale...................................... 0.04 0 2 2
Sperm whale..................................... 2.89 1 159 160
Cuvier's beaked whale........................... 2.62 1 143 144
Arnoux's beaked whale........................... 2.62 1 143 144
Southern bottlenose whale....................... 1.74 0 96 96
Shepard's beaked whale.......................... 1.74 0 96 96
Hector's beaked whale........................... 1.74 0 96 96
True's beaked whale............................. 0.87 0 48 48
Gray's beaked whale............................. 3.49 1 191 192
Andrew's beaked whale........................... 1.74 0 96 96
Strap-toothed whale............................. 2.62 1 143 144
Blainville's beaked whale....................... 0.87 0 48 48
Spade-toothed whale............................. 0.87 0 48 48
Bottlenose dolphin.............................. 5.12 1 281 282
Short-beaked common dolphin..................... 10.25 2 562 564
Dusky dolphin................................... 5.12 1 281 282
Southern right-whale dolphin.................... 3.07 1 168 169
Risso's dolphin................................. 2.05 0 112 112
False killer whale.............................. 3.07 1 168 169
Killer whale.................................... 1.91 0 105 105
Long-finned pilot whale......................... 8.28 2 454 456
Short-finned pilot whale........................ 4.10 1 225 226
Pygmy sperm whale............................... 1.74 4 91 95
Hourglass dolphin............................... 4.16 10 219 229
Hector's dolphin................................ 0 0 0 0
Spectacled porpoise............................. 0 0 0 0
New Zealand fur seal............................ 22.50 5 1234 1239
New Zealand sea lion............................ 0 0 0 0
Southern elephant seal.......................... 4.50 2 245 247
Leopard seal.................................... 2.25 1 123 124
----------------------------------------------------------------------------------------------------------------
\1\ Includes additional 25 percent contingency for potential additional survey operations and additional 25
percent contingency to account for uncertainties in density estimates.
[[Page 56138]]
Table 12--Numbers of Potential Incidental Take of Marine Mammals Authorized During L-DEO's South Island 2-D
Seismic Survey Off New Zealand
----------------------------------------------------------------------------------------------------------------
Total Level A
Density (#/ Level A takes Level B takes and Level B
Species 1,000 km\2\) authorized \1\ authorized \1\ takes
authorized \1\
----------------------------------------------------------------------------------------------------------------
Southern right whale............................ 0.24 1 15 16
Pygmy right whale............................... 0.10 0 6 6
Humpback whale.................................. 0.24 1 12 13
Bryde's whale................................... 0.14 0 0 0
Common minke whale.............................. 0.14 1 9 10
Antarctic minke whale........................... 0.14 1 9 10
Sei whale....................................... 0.14 1 9 10
Fin whale....................................... 0.25 1 15 16
Blue whale...................................... 0.04 0 2 2
Sperm whale..................................... 2.89 0 190 190
Cuvier's beaked whale........................... 2.62 0 172 172
Arnoux's beaked whale........................... 2.62 0 172 172
Southern bottlenose whale....................... 1.74 0 114 114
Shepard's beaked whale.......................... 1.74 0 114 114
Hector's beaked whale........................... 1.74 0 114 114
True's beaked whale............................. 0.87 0 57 57
Gray's beaked whale............................. 3.49 0 229 229
Andrew's beaked whale........................... 1.74 0 114 114
Strap-toothed whale............................. 2.62 0 172 172
Blainville's beaked whale....................... 0.87 0 57 57
Spade-toothed whale............................. 0.87 0 57 57
Bottlenose dolphin.............................. 5.12 1 314 315
Short-beaked common dolphin..................... 10.25 1 314 315
Dusky dolphin................................... 5.12 1 502 503
Southern right-whale dolphin.................... 3.07 0 188 188
Risso's dolphin................................. 2.05 0 126 126
False killer whale.............................. 3.07 1 188 189
Killer whale.................................... 1.91 0 126 126
Long-finned pilot whale......................... 8.28 1 543 544
Short-finned pilot whale........................ 4.10 0 126 126
Pygmy sperm whale............................... 1.74 5 109 114
Hourglass dolphin............................... 4.16 12 261 273
Hector's dolphin................................ 0 0 2 2
Spectacled porpoise............................. 0 6 120 126
New Zealand fur seal............................ 22.50 2 1477 1479
New Zealand sea lion............................ 0 1 591 592
Southern elephant seal.......................... 4.50 2 294 296
Leopard seal.................................... 2.25 1 147 148
----------------------------------------------------------------------------------------------------------------
\1\ Includes additional 25 percent contingency for potential additional survey operations and additional 25
percent contingency to account for uncertainties in density estimates.
Table 13--Total Numbers of Potential Incidental Take of Marine Mammals Authorized During L-DEO's North Island 3-
D Survey, North Island 2-D Survey, and South Island 3-D Surveys of the R/V Langseth Off New Zealand
----------------------------------------------------------------------------------------------------------------
Total
authorized
Total Level A Level A and
Species Density (#/ Level A takes Level B takes and Level B Level B takes
1,000 km\2\) authorized \1\ authorized \1\ takes as a
authorized \1\ percentage of
population
----------------------------------------------------------------------------------------------------------------
Southern right whale............ 0.24 3 51 54 0.45
Pygmy right whale............... 0.10 1 20 21 N.A.
Humpback whale.................. 0.19 3 48 51 0.12
Bryde's whale................... 0.00 1 22 23 0.05
Common minke whale.............. 0.14 2 31 33 <0.01
Antarctic minke whale........... 0.14 2 31 33 <0.01
Sei whale....................... 0.14 2 31 33 0.33
Fin whale....................... 0.25 3 52 55 0.37
Blue whale...................... 0.04 0 8 8 0.21
Sperm whale..................... 2.89 2 654 656 2.19
Cuvier's beaked whale........... 2.62 2 591 593 0.10
Arnoux's beaked whale........... 2.62 2 591 593 0.10
Southern bottlenose whale....... 1.74 0 394 394 0.07
Shepard's beaked whale.......... 1.74 0 394 394 0.07
Hector's beaked whale........... 1.74 0 394 394 0.07
[[Page 56139]]
True's beaked whale............. 0.87 0 197 197 N.A.
Gray's beaked whale............. 3.49 2 788 790 0.13
Andrew's beaked whale........... 1.74 0 394 394 0.07
Strap-toothed whale............. 2.62 2 591 593 0.10
Blainville's beaked whale....... 0.87 0 197 197 0.03
Spade-toothed whale............. 0.87 0 197 197 0.03
Bottlenose dolphin.............. 4.78 3 1135 1138 N.A.
Short-beaked common dolphin..... 4.78 5 1956 1961 N.A.
Dusky dolphin................... 7.65 3 1323 1326 11.05
Southern right-whale dolphin.... 2.87 2 680 682 N.A.
Risso's dolphin................. 1.91 0 454 454 N.A.
False killer whale.............. 2.87 3 680 683 N.A.
Killer whale.................... 1.91 0 433 433 0.54
Long-finned pilot whale......... 8.28 5 1869 1874 0.94
Short-finned pilot whale........ 1.91 2 783 785 N.A.
Pygmy sperm whale............... 1.74 15 377 392 N.A.
Hourglass dolphin............... 4.16 37 904 941 0.63
Hector's dolphin................ 0.04 0 2 2 0.01
Spectacled porpoise............. 1.91 6 120 126 N.A.
New Zealand fur seal............ 22.50 11 5084 5095 2.55
New Zealand sea lion............ 9.00 1 591 592 5.99
Southern elephant seal.......... 4.50 7 1011 1018 0.17
Leopard seal.................... 2.25 3 506 509 0.23
----------------------------------------------------------------------------------------------------------------
\1\ Includes additional 25 percent contingency for potential additional survey operations and additional 25
percent contingency to account for uncertainties in density estimates.
As described above, the take estimates shown in Tables 10, 11, 12
and 13 have been revised slightly since we published the notice of the
proposed IHA in the Federal Register (82 FR 45116; September 27, 2017).
Revised take estimates are higher in some cases, and lower in some
cases, in comparison to the take estimates described in the notice of
the proposed IHA. These revisions have not affected our preliminary
determinations.
It should be noted that the take numbers shown in Tables 10, 11, 12
and 13 are expected to be conservative for several reasons. First, in
the calculations of estimated take, 50 percent has been added in the
form of operational survey days (equivalent to adding 50 percent to the
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, and in
recognition of the uncertainties in the density estimates used to
estimate take as described above. Additionally, marine mammals would be
expected to move away from a loud sound source that represents an
aversive stimulus, such as an airgun array, potentially reducing the
number of Level A takes. However, the extent to which marine mammals
would move away from the sound source is difficult to quantify and is
therefore not accounted for in the take estimates shown in 11, 12, 13
and 14.
For some marine mammal species, we authorize a different number of
incidental takes than the number of incidental takes requested by L-DEO
(see Tables 18, 19 and 20 in the IHA application for requested take
numbers). For instance, for several species, L-DEO increased the take
request from the calculated take number to 1 percent of the estimated
population size. We do not believe it is likely that 1 percent of the
estimated population size of those species will be taken by L-DEO's
planned surveys, therefore we do not authorize the take numbers
requested by L-DEO in their IHA application (LGL, 2017). However, in
recognition of the uncertainties in the density estimates used to
estimate take as described above, we believe it is reasonable to assume
that actual takes may exceed numbers of takes calculated based on
available density estimates; therefore, we have increased take
estimates for all marine mammal species by an additional 25 percent, to
account for the fact that density estimates used to estimate take may
be underestimates of actual densities of marine mammals in the survey
area. Additionally, L-DEO requested authorization for 10 takes of
Hector's dolphins during the North Island 2-D survey (LGL, 2017).
However, we do not authorize any takes of Hector's dolphins or Maui
dolphins during North Island surveys. We believe the likelihood of the
planned North Island 2-D survey encountering a Hector's dolphin or Maui
dolphin is so low as to be discountable. As described above, the North
Island subpopulation of Hector's dolphin (aka Maui dolphin) is very
unlikely to be encountered during either planned North Island survey
due to the very low estimated abundance of the subpopulation and due to
the geographic isolation of the subpopulation (currently limited to the
west coast of the North Island, whereas all planned North Island
surveys would occur on the eastern side of the island). As such, we do
not authorize any takes of Hector's dolphins or Maui dolphins during L-
DEO's planned North Island surveys.
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
[[Page 56140]]
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.
L-DEO has reviewed mitigation measures employed during seismic
research surveys authorized by NMFS under previous incidental
harassment authorizations, as well as recommended best practices in
Richardson et al. (1995), Pierson et al. (1998), Weir and Dolman
(2007), Nowacek et al. (2013), Wright (2014), and Wright and Cosentino
(2015), and has incorporated a suite of proposed mitigation measures
into their project description based on the above sources.
To reduce the potential for disturbance from acoustic stimuli
associated with the activities, L-DEO 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) Vessel strike avoidance measures.
In addition to the mitigation measures proposed by L-DEO, NMFS has
incorporated the following additional measures:
(1) Shutdown upon observation of a large whale with calf at any
distance;
(2) Shutdown upon observation of a Hector's dolphin or Maui dolphin
(during North Island 2-D and North Island 3-D surveys only) at any
distance;
(3) Shutdown upon observation of an aggregation (6 or more) of
large whales of any species at any distance;
(4) Shutdown upon any observation (visual or acoustic) of a beaked
whale or Kogia spp. at any distance; and
(5) Shutdown upon acoustic detection of a sperm whale (with certain
exceptions) at any distance.
As described above, measures (3), (4) and (5) incorporated by NMFS
above were added to the suite of mitigation measures after we published
the notice of the proposed IHA in the Federal Register (82 FR 45116;
September 27, 2017), in response to comments received from the
Commission.
Vessel-Based Visual Mitigation Monitoring
Protected Species Observer (PSO) observations will take place
during all daytime airgun operations and nighttime start ups (if
applicable) of the airguns. Airgun operations will be suspended when
marine mammals are observed within, or about to enter, designated
Exclusion Zones (as described below). PSOs will also watch for marine
mammals near the vessel for at least 30 minutes prior to the planned
start of airgun operations. PSOs will monitor the entire extent of the
modeled Level B harassment zone (Table 3) (or, as far as they are able
to see, if they cannot see to the extent of the estimated Level B
harassment zone). Observations will also be made during daytime periods
when the Langseth 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.
During seismic operations, a minimum of four visual PSOs will be
based aboard the Langseth. PSOs will be appointed by L-DEO, with NMFS'
approval. During the majority of seismic operations, two PSOs will
monitor for marine mammals around the seismic vessel. Use of two
simultaneous observers increases the effectiveness of detecting marine
mammals around the source vessel. However, during meal times, only one
PSO may be on duty. PSO(s) will be on duty in shifts of duration no
longer than 4 hours. Other crew will 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 will
be given additional instruction in detecting marine mammals and
implementing mitigation requirements. The Langseth is a suitable
platform for marine mammal observations. When stationed on the
observation platform, PSOs will have a good view around the entire
vessel. During daytime, the PSO(s) will scan the area around the vessel
systematically with reticle binoculars (e.g., 7 x 50 Fujinon), Big-eye
binoculars (25 x 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 will 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 high energy seismic survey, with no
more than eighteen months elapsed since the conclusion of the at-sea
experience. One ``experienced'' visual PSO will be designated as the
lead for the entire protected species observation team. The lead will
coordinate duty schedules and roles for the PSO team and serve as
primary point of contact for the vessel operator. The lead PSO will
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
[[Page 56141]]
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.
Vessel-Based Passive Acoustic Mitigation Monitoring
Passive acoustic monitoring (PAM) will take place to complement the
visual monitoring program and to inform mitigation measures. 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 will serve to inform mitigation measures and to
alert visual observers (if on duty) when vocalizing cetaceans are
detected. PAM 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. PAM will 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 will
connect the tow cable to the electronics unit on board where the
acoustic station, signal conditioning, and processing system will be
located. The acoustic signals received by the hydrophones are
amplified, digitized, and then processed by the software.
At least one acoustic PSO (in addition to the four visual PSOs)
will be on board. The towed hydrophones will 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
Langseth 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 will 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, the acoustic PSO will take
necessary action depending on the species and location of the animal
detected. If the species and/or location of the animal(s) warrants
immediate shutdown of the array, the acoustic PSO will contact the
vessel operator immediately to call for a shutdown (see the section on
Mitigation, below, for scenarios that require shutdown based on
acoustic detection), If the species and/or location of the animal(s)
does not warrant immediate shutdown, the acoustic PSO will contact
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 shutdown, if required. The information
regarding the marine mammal acoustic detection will be entered into a
database.
In summary, a typical daytime cruise will have scheduled two
observers (visual) on duty from the observation platform, and an
acoustic observer on the passive acoustic monitoring system.
Exclusion Zone and Buffer Zone
An exclusion zone (EZ) is a defined area within which occurrence of
a marine mammal triggers mitigation action intended to reduce the
potential for certain outcomes, e.g., auditory injury, disruption of
critical behaviors. The PSOs will establish a minimum EZ with a 500 m
radius for the 36 airgun array and the 18 airgun array. The 500 m EZ
will 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 will be powered down (see Power Down
Procedures below). In addition to the 500 m EZ for the full arrays, a
100 m exclusion zone will be established for the single 40 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 will be shut down entirely (see Shutdown Procedures
below). Additionally, power down of the full arrays will last no more
than 30 minutes maximum at any given time; thus the arrays will be shut
down entirely if, after 30 minutes of the array being powered down, a
marine mammal remains inside the 500 m EZ (with the exception of
spectacled porpoise and bottlenose, hourglass, and Hector's dolphins,
as described above).
In their IHA application, L-DEO proposed to establish EZs based
upon modeled radial distances to auditory injury zones (e.g., power
down would occur when a marine mammal entered or appeared likely to
enter the zone(s) within which auditory injury is expected to occur
based on modeling) (Tables 6, 7, 8). However, we instead require the
500 m EZ as described above. The 500 m 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. Additionally, a 500-m EZ is expected to minimize
the likelihood that marine mammals will be exposed to levels likely to
result in more severe behavioral responses. Although significantly
greater distances may be observed from an elevated platform under good
conditions, we believe that 500 m is likely regularly attainable for
PSOs using the naked eye during typical conditions.
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.
Use of monitoring and shutdown or power-down measures within
defined 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
definition of an exclusion zone on the basis of cumulative sound
exposure level thresholds, which require that an animal accumulate some
level of sound energy exposure over some period of time (e.g., 24
hours), has questionable relevance as a standard protocol. A PSO aboard
a mobile source will typically have no ability to monitor an animal's
position relative to the acoustic source
[[Page 56142]]
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.
Cumulative SEL thresholds are more relevant for purposes of
modeling the potential for auditory injury than they are for dictating
real-time mitigation, though they can be informative (especially in a
relative sense). 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 is expected to contain all potential auditory injury for all
marine mammals (high-frequency, mid-frequency and low-frequency
cetacean functional hearing groups and otariid and phocid pinnipeds) as
assessed against peak pressure thresholds (NMFS, 2016) (Tables 6, 7,
8). It is also expected to contain all potential auditory injury for
high-frequency and mid-frequency cetaceans as well as otariid and
phocid pinnipeds as assessed against SELcum thresholds
(NMFS, 2016) (Tables 6, 7, 8). It has 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 the Bureau of Ocean
Energy Management (BOEM) pursuant to the Outer Continental Shelf Lands
Act (43 U.S.C. 1331-1356)). In summary, a practicable criterion, such
as the EZs described above, 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 will also establish and monitor a 500 m buffer zone (i.e.,
500 m in addition to the 500 m EZ). During operation of the airgun
arrays, occurrence of marine mammals within the 500 m buffer zone (but
outside the 500 m EZ) will be communicated to the vessel operator to
prepare for potential power down or shutdown of the acoustic source.
The buffer zone is discussed further under Ramp Up Procedures below.
PSOs will also monitor the entire extent of the estimated Level B
harassment zone (Table 3) (or, as far as they are able to see, if they
cannot see to the extent of the estimated Level B harassment zone).
Power Down Procedures
A power down involves decreasing the number of airguns in use such
that the smallest single element of the array is in operation (i.e.,
one 40-in\3\ airgun), with the result 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. The continued operation of one 40-
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 array will 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 array will be powered down immediately.
During a power down of the airgun array, the 40-in\3\ airgun will be
operated.
Following a power down, airgun activity will not resume until the
marine mammal has cleared the 500 m EZ. The animal will 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 and pinnipeds; 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 will be in place for all marine
mammals, with the exception of certain 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 applies solely to specific species of small
dolphins: Short-beaked common dolphin, dusky dolphin, and southern
right whale dolphin. If there is uncertainty regarding identification
(i.e., whether the observed animal(s) belongs to the species described
above), the power down or shutdown must be implemented. Note that
bottlenose, hourglass, and Hector's dolphins and spectacled porpoise
are not included in the power down/shutdown exception.
We include this small delphinoid exception because power-down/
shutdown requirements for small delphinoids under all circumstances
represent practicability concerns without likely commensurate benefits
for the animals in question. Small delphinoids are generally the most
commonly observed marine mammals in the specific geographic region and
would typically be the only marine mammals likely to intentionally
approach the vessel. As described 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 in the Federal Register notice of
the proposed IHA (82 FR 45116; September 27, 2017) for further
discussion of sound metrics and thresholds and marine mammal hearing.
Bottlenose dolphins are excluded from the power down waiver due to
concerns from the New Zealand Department of Conservation, while
hourglass, spectacled, and Hector's dolphins are excluded from the
power down waiver due to their functional hearing range (they are
classified as high frequency cetaceans which would make them more
susceptible to harassment or possible injury as a result of exposure to
airgun sounds).
A large body of anecdotal evidence indicates that small delphinoids
commonly approach vessels and/or towed arrays during active sound
production for purposes of bow riding, with no apparent effect observed
in those delphinoids (e.g., Barkaszi et al., 2012). The potential for
increased shutdowns resulting from such a measure would require the
Langseth to revisit the missed track line to reacquire data, resulting
in an overall increase in the total sound energy input to the marine
environment and an increase in
[[Page 56143]]
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.
A power down could occur for no more than 30 minutes maximum at any
given time. If, after 30 minutes of the array being powered down,
marine mammals had not cleared the 500 m EZ (as described above), a
shutdown of the array will be implemented (see Shut Down Procedures,
below). Power down is only allowed in response to the presence of
marine mammals within the designated EZ. Thus, the single 40 in\3\
airgun, which will be operated during power downs, may not be operated
continuously throughout the night or during transits from one line to
another.
Shut Down Procedures
The single 40-in\3\ operating airgun will be shut down if a marine
mammal is seen within or approaching the 100 m EZ for the single 40-
in\3\ airgun. Shutdown will be implemented if (1) an animal enters the
100 m EZ of the single 40-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 40-in\3\ airgun when more than one airgun (typically the
full array) is operating. Airgun activity will not resume until the
marine mammal has cleared the 500 m EZ. Criteria for judging that the
animal has cleared the EZ will be as described above. A shutdown of the
array will be implemented if, after 30 minutes of the array being
powered down, marine mammals have not cleared the 500 m EZ (as
described above).
The shutdown requirement, like the power down requirement, is
waived for dolphins of the following species: Short-beaked common
dolphin, dusky dolphin and southern right whale dolphin. If there is
uncertainty regarding identification (i.e., whether the observed
animal(s) belongs to the species described above), the shutdown will be
implemented.
Other Shutdown Requirements--In addition to the shutdown
requirement described above, NMFS also requires shutdown of the
acoustic source in the event of certain other observations regardless
of the defined exclusion zone. While visual PSOs should focus
observational effort within the vicinity of the acoustic source and
vessel (i.e., approximately 1 km radius), this does not preclude them
from periodic scanning of the remainder of the visible area, and there
is no reason to believe that such periodic scans by professional PSOs
would hamper their ability to maintain observation of areas closer to
the source and vessel. These circumstances include:
Upon observation of a large 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. Groups of whales are likely to be
more susceptible to disturbance when calves are present (e.g., Bauer et
al., 1993), and disturbance of cow-calf pairs could potentially result
in separation of vulnerable calves from adults. McCauley et al. (2000a)
found that groups of humpback whale females with calves consistently
avoided a single operating airgun, while male humpbacks were attracted
to it, concluding that cow-calf pairs are more likely to exhibit
avoidance responses to unfamiliar sounds and that such responses should
be a focus of management. Behavioral disturbance has been implicated in
mother-calf separations for odontocete species as well (Noren and
Edwards, 2007; Wade et al., 2012). Separation, if it occurred, could be
exacerbated by airgun signals masking communication between adults and
the separated calf (Videsen et al., 2017). Absent separation, airgun
signals can disrupt or mask vocalizations essential to mother-calf
interactions. Reductions in the probability of calf survival for gray
whales have been linked to airgun surveys in Russia (Cooke et al.,
2016).
Upon acoustic detection of a sperm whale (except in cases
where the location of an acoustically detected sperm whale can be
definitively localized as outside the 500 m EZ). Sperm whales are not
necessarily expected to display physical avoidance of sound sources
(e.g., Madsen et al., 2002a; Jochens et al., 2008; Winsor et al.,
2017). Although Winsor et al. (2017) report that distances and
orientations between tagged whales and active airgun arrays appeared to
be randomly distributed with no evidence of horizontal avoidance, it
must be noted that their study was to some degree precipitated by an
earlier observation of significantly decreased sperm whale density in
the presence of airgun surveys (Mate et al., 1994). However, effects on
vocal behavior are common (e.g., Watkins and Schevill, 1975; Watkins et
al., 1985). The sperm whale's primary means of locating prey is
echolocation (Miller et al., 2004), and multiple studies have shown
that noise can disrupt feeding behavior and/or significantly reduce
foraging success for sperm whales at relatively low levels of exposure
(e.g., Miller et al., 2009, 2012; Isojunno et al., 2016; Sivle et al.,
2012; Cure et al., 2016). Effects on energy intake with no immediate
compensation, as is suggested by disruption of foraging behavior
without corollary movements to new locations, would be expected to
result in bioenergetics consequences to individual whales.
We also considered requirement of shutdown upon visual detection of
sperm whales at any distance. Here, we assume that acoustic detections
of sperm whales would most likely be representative of the foraging
behavior we intend to minimize disruption of, while visual observations
of sperm whales would represent resting between bouts of such behavior.
Occurrence of resting sperm whales at distances beyond the exclusion
zone may not indicate a need to implement shutdown. If the location of
an acoustically detected sperm whale can be definitively localized by
the PAM operator as outside the 500 m EZ, then the requirement to
shutdown the array is waived. If there is any uncertainty as to whether
or not an acoustically detected sperm whale is within the 500 m EZ,
shutdown must be implemented.
Upon any observation (visual or acoustic) of a beaked
whale or Kogia spp. These species are behaviorally sensitive deep
divers and it is possible that disturbance could provoke a severe
behavioral response leading to injury (e.g., Wursig et al., 1998; Cox
et al., 2006). Unlike the sperm whale, we recognize that there are
generally low detection probabilities for beaked whales and Kogia spp.,
meaning that many animals of these species may go undetected. Barlow
(1999) estimates such probabilities at 0.23 to 0.45 for Cuvier's and
Mesoplodont beaked whales, respectively. However, Barlow and Gisiner
(2006) predict a roughly 24-48 percent reduction in the probability of
detecting beaked whales during seismic mitigation monitoring efforts as
compared with typical research survey
[[Page 56144]]
efforts, and Moore and Barlow (2013) noted a decrease in g(0) for
Cuvier's beaked whales from 0.23 at BSS 0 (calm) to 0.024 at BSS 5.
Similar detection probabilities have been noted for Kogia spp., though
they typically travel in smaller groups and are less vocal, thus making
detection more difficult (Barlow and Forney, 2007). Because it is
likely that only a small proportion of beaked whales and Kogia spp.
potentially affected by the planned surveys would actually be detected,
it is important to avoid potential impacts when possible.
Upon visual observation of an aggregation (6 or more) of
large whales of any species (i.e., sperm whale or any baleen whale)
(e.g., feeding, socializing, etc.). Under these circumstances, we
assume that the animals are engaged in some important behavior (e.g.,
feeding, socializing) that should not be disturbed. By convention, we
define an aggregation as six or more animals.
Upon observation (visual or acoustic) of a Hector's
dolphin or Maui dolphin (during North Island and South Island surveys)
at any distance. As described above, the Maui dolphin is considered one
of the rarest dolphins in the world with a population size estimated at
just 63 individuals (Baker et al. 2016). It has undergone a marked
reduction in range (Dawson et al. 2001; Slooten et al. 2005), and
currently faces a high risk of extinction (Manning and Grantz, 2016).
The shutdown requirement for Hector's/Maui dolphin during North Island
surveys is designed to avoid any potential for exposure of a Maui
dolphin to seismic airgun sounds. Maui dolphins are not expected to
occur in the planned survey areas off the North Island based on their
current range. However, as described above, there have been occasional
sightings of Hector's dolphins off the east coast of the North Island
though it is unclear whether those individuals may have originated from
the South Island Hector's dolphin populations (Baker 1978, Russell
1999, Ferreira and Roberts 2003, Slooten et al. 2005, DuFresne 2010,
Berkenbusch et al. 2013; Torres et al. 2013; Pati[ntilde]o-P[eacute]rez
2015; NZDOC 2017). While we have determined the likelihood of L-DEO's
planned North Island surveys encountering a Hector's dolphin or Maui
dolphin is extremely low, we nonetheless include this measure to
further minimize the already extremely unlikely potential for exposure
of a Maui dolphin to airgun sounds. Also as described above, Hector's
dolphins have relatively small home ranges and high site fidelity and a
genetically distinct and localized population occurs in Te Waewae Bay
(Mackenzie and Clement, 2014). Due to the limited range and high site
fidelity of the population of Hector's dolphin that occurs in Te Waewae
Bay and the proximity of the planned South Island 2-D survey with Te
Waewae Bay we have included this requirement to protect the South
Island Hector's dolphin. The requirement to shut down on acoustic
detection applies when the acoustic detection can be positively
identified as originating from a Hector's dolphin.
In the event of a shutdown due to visual observation of a
beaked whale, Kogia spp., an aggregation of large whales, or large
whale with calf, ramp-up procedures will not be initiated until the
animal(s) that triggered the shutdown has not been seen at any distance
for 30 minutes. In the event of a shutdown due to visual or confirmed
acoustic detection of a Hector's or Maui dolphin, ramp-up procedures
will not be initiated until the Hector's/Maui dolphin has not been
visually or acoustically detected at any distance for 15 minutes. In
the event of a shutdown due to acoustic detection of a sperm whale,
Kogia spp., or beaked whale, ramp-up procedures will not be initiated
until the animal(s) that triggered the shutdown has not been detected
acoustically for 30 minutes.
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 is required after the array is powered down
or shut down due to mitigation. 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. This is the only
scenario under which ramp up is not required.
Ramp-up will begin by activating a single airgun of the smallest
volume in the array and will continue in stages by doubling the number
of active elements at the commencement of each stage, with each stage
of approximately the same duration.
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 will not
be initiated until all marine mammals have cleared the EZ, during the
day or night. Visual and acoustic PSOs are 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) will be implemented as though the full array were
operational. Criteria for clearing the EZ will be as described above.
Thirty minutes of pre-clearance observation of the 500 m EZ and 500
m buffer zone are required prior to ramp-up following any extended
deactivation of the array (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 is observed within or approaching the 500 m EZ during this pre-
clearance period, ramp-up will not be initiated until all marine
mammals have cleared the EZ. Criteria for clearing the EZ will be as
described above.
Ramp-up will be planned to occur during periods of good visibility
when possible. However, ramp-up is allowed at night and during poor
visibility if the 500 m EZ and 500 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. Ramp-up of the array may not occur at
night or during poor visibility if the PAM system is not functional.
The operator is required to notify a designated PSO of the planned
start of ramp-up as agreed-upon with the lead PSO. A designated PSO
must be notified again immediately prior to initiating ramp-up
procedures and the operator must receive confirmation from the PSO to
proceed. The operator must provide information to PSOs documenting that
appropriate procedures were followed. Following deactivation of the
array for reasons other than mitigation, the operator is required to
communicate the near-term operational plan to the lead PSO with
justification for any planned nighttime ramp-up.
L-DEO proposed that ramp up would not occur following an extended
power down (LGL 2017). However, as we do not allow extended power downs
during the planned surveys, we also do not include this as a mitigation
measure; instead, ramp up is required after any power down or shutdown
of the array (with the one exception as described above). L-DEO also
proposed that ramp up would occur when the airgun array begins
operating after 8 minutes without
[[Page 56145]]
airgun operations (LGL 2017). However, we instead include the criteria
for ramp-up as described above.
Vessel Strike Avoidance
Vessel strike avoidance measures are intended to minimize the
potential for collisions with marine mammals. We note that these
requirements do not apply in any case where compliance would create an
imminent and serious threat to a person or vessel or to the extent that
a vessel is restricted in its ability to maneuver and, because of the
restriction, cannot comply.
The vessel strike avoidance measures include the following: Vessel
operator and crew will maintain a vigilant watch for all marine mammals
and slow down or stop the vessel or alter course to avoid striking any
marine mammal. A visual observer aboard the vessel will monitor a
vessel strike avoidance zone around the vessel according to the
parameters stated below. Visual observers monitoring the vessel strike
avoidance zone will be either third-party observers or crew members,
but crew members responsible for these duties will be provided
sufficient training to distinguish marine mammals from other phenomena.
Vessel strike avoidance measures will be followed during surveys and
while in transit.
The vessel will maintain a minimum separation distance of 100 m
from large whales (i.e., baleen whales and sperm whales). If a large
whale is within 100 m of the vessel the vessel will reduce speed and
shift the engine to neutral, and will not engage the engines until the
whale has moved outside of the vessel's path and the minimum separation
distance has been established. If the vessel is stationary, the vessel
will not engage engines until the whale(s) has moved out of the
vessel's path and beyond 100 m. The vessel will maintain a minimum
separation distance of 50 m from all other marine mammals (with the
exception of short-beaked common dolphins, dusky dolphins and southern
right whale dolphins that approach the vessel, as described above). If
an animal is encountered during transit, the vessel will attempt to
remain parallel to the animal's course, avoiding excessive speed or
abrupt changes in course. Vessel speeds will be reduced to 10 knots or
less when mother/calf pairs, pods, or large assemblages of cetaceans
are observed near the vessel.
Based on our evaluation of the applicant's proposed measures, NMFS
has determined that the mitigation measures provide the means of
effecting the least practicable impact on the affected species or
stocks and their habitat, paying particular attention to rookeries,
mating grounds, and areas of similar significance.
Monitoring and Reporting
In order to issue an IHA for an activity, Section 101(a)(5)(D) of
the MMPA states that NMFS must set forth requirements pertaining to the
monitoring and reporting of such taking. The MMPA implementing
regulations at 50 CFR 216.104(a)(13) indicate that requests for
authorizations must include the suggested means of accomplishing the
necessary monitoring and reporting that will result in increased
knowledge of the species and of the level of taking or impacts on
populations of marine mammals that are expected to be present in the
action area. Effective reporting is critical both to compliance as well
as ensuring that the most value is obtained from the required
monitoring.
Monitoring and reporting requirements prescribed by NMFS should
contribute to improved understanding of one or more of the following:
Occurrence of marine mammal species or stocks in the area
in which take is anticipated (e.g., presence, abundance, distribution,
density);
Nature, scope, or context of likely marine mammal exposure
to potential stressors/impacts (individual or cumulative, acute or
chronic), through better understanding of: (1) Action or environment
(e.g., source characterization, propagation, ambient noise); (2)
affected species (e.g., life history, dive patterns); (3) co-occurrence
of marine mammal species with the action; or (4) biological or
behavioral context of exposure (e.g., age, calving or feeding areas);
Individual marine mammal responses (behavioral or
physiological) to acoustic stressors (acute, chronic, or cumulative),
other stressors, or cumulative impacts from multiple stressors;
How anticipated responses to stressors impact either: (1)
Long-term fitness and survival of individual marine mammals; or (2)
populations, species, or stocks;
Effects on marine mammal habitat (e.g., marine mammal prey
species, acoustic habitat, or other important physical components of
marine mammal habitat); and
Mitigation and monitoring effectiveness.
L-DEO 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.
L-DEO's monitoring and reporting plan includes the following
measures:
Vessel-Based Visual Monitoring
As described above, PSO observations will take place during daytime
airgun operations and nighttime start ups (if applicable) of the
airguns. During seismic operations, at least four visual PSOs will be
based aboard the Langseth. PSOs will be appointed by L-DEO with NMFS
approval. During the majority of seismic operations, two PSOs will
monitor for marine mammals around the seismic vessel. Use of two
simultaneous observers increases the effectiveness of detecting animals
around the source vessel. However, during meal times, only one PSO may
be on duty. PSOs will be on duty in shifts of duration no longer than 4
hours. Other crew will also be instructed to assist in detecting marine
mammals and in implementing mitigation requirements (if practical).
During daytime, PSOs will scan the area around the vessel
systematically with reticle binoculars (e.g., 7 x 50 Fujinon), Big-eye
binoculars (25 x 150), and with the naked eye.
PSOs will 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 will be used to estimate
numbers of animals potentially `taken' by harassment (as defined in the
MMPA). They will also provide information needed to order a power down
or shutdown of airguns when a marine mammal is within or near the EZ.
When a sighting is made, the following information about the
sighting will be recorded:
1. Species, group size, age/size/sex categories (if determinable),
behavior when first sighted and after initial sighting, heading (if
consistent), bearing and distance from seismic vessel, sighting cue,
apparent reaction to the airguns or vessel (e.g., none, avoidance,
approach, paralleling, etc.), and behavioral pace; and
2. Time, location, heading, speed, activity of the vessel, sea
state, visibility, and sun glare.
All observations and power downs or shutdowns will be recorded in a
standardized format. Data will be entered into an electronic database.
The accuracy of the data entry will be verified by computerized data
validity checks as the data are entered and by subsequent manual
checking of the database. These procedures will allow
[[Page 56146]]
initial summaries of data to be prepared during and shortly after the
field program and will 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 will 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 will provide:
1. The basis for real-time mitigation (airgun power down or
shutdown);
2. Information needed to estimate the number of marine mammals
potentially taken by harassment, which must be reported to NMFS;
3. Data on the occurrence, distribution, and activities of marine
mammals in the area where the seismic study is conducted;
4. Information to compare the distance and distribution of marine
mammals relative to the source vessel at times with and without seismic
activity; and
5. Data on the behavior and movement patterns of marine mammals
seen at times with and without seismic activity.
Vessel-Based Passive Acoustic Monitoring
As described above, the acoustic PSO will monitor the PAM system in
real time. When a vocalization is detected, the acoustic PSO will take
necessary action depending on the species and location of the animal
detected, whether immediately calling for a shutdown or immediately
contacting visual PSOs to alert them to the presence of marine mammals
in order to facilitate a power down or shutdown, if required.
PAM will also take place to complement the visual monitoring
program as described above. Please see the Mitigation section above for
a description of the PAM system and the acoustic PSO's duties. The
acoustic PSO will 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 will also be recorded for further
analysis.
Reporting
A report will be submitted to NMFS within 90 days after the end of
the cruise. The report will describe the operations that were conducted
and sightings of marine mammals near the operations. The report will
provide full documentation of methods, results, and interpretation
pertaining to all monitoring. The 90-day report will summarize the
dates and locations of seismic operations, and all marine mammal
sightings (dates, times, locations, activities, associated seismic
survey activities). The report will also include estimates of the
number and nature of exposures that occurred above the harassment
threshold based on PSO observations, including an estimate of those on
the trackline but not detected.
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
planned seismic surveys to be similar in nature. Where there are
meaningful differences between species or stocks, or groups of species,
in anticipated individual responses to activities, impact of expected
take on the population due to differences in population status, or
impacts on habitat, NMFS has identified species-specific factors to
inform the analysis. As described above, we authorize only the takes
estimated to occur outside of New Zealand territorial sea (Tables 10,
11, 12 and 13); however, for the purposes of our negligible impact
analysis and determination, we consider the total impacts to the
affected marine mammal populations resulting from the specified
activity, including takes that are expected to occur within the
territorial sea (Table 14).
Table 14--Total Numbers of Potential Incidental Take of Marine Mammals During Portions of L-DEO's North Island 2-
D, North Island 3-D, and South Island 2-D Surveys That Occur in the New Zealand Territorial Sea
----------------------------------------------------------------------------------------------------------------
Total
Estimated Estimated estimated
Species Level A takes Level B takes Level A and
\1\ \1\ Level B takes
\1\
----------------------------------------------------------------------------------------------------------------
Southern right whale............................................ 0 25 25
Pygmy right whale............................................... 0 11 11
Humpback whale.................................................. 0 24 24
Bryde's whale................................................... 0 14 14
Common minke whale.............................................. 0 16 16
Antarctic minke whale........................................... 0 16 16
Sei whale....................................................... 0 16 16
[[Page 56147]]
Fin whale....................................................... 0 25 25
Blue whale...................................................... 0 6 6
Sperm whale..................................................... 0 278 278
Cuvier's beaked whale........................................... 0 251 251
Arnoux's beaked whale........................................... 0 251 251
Southern bottlenose whale....................................... 0 169 169
Shepard's beaked whale.......................................... 0 169 169
Hector's beaked whale........................................... 0 169 169
True's beaked whale............................................. 0 85 85
Gray's beaked whale............................................. 0 334 334
Andrew's beaked whale........................................... 0 169 169
Strap-toothed whale............................................. 0 251 251
Blainville's beaked whale....................................... 0 85 85
Spade-toothed whale............................................. 0 85 85
Bottlenose dolphin.............................................. 0 486 486
Short-beaked common dolphin..................................... 0 918 918
Dusky dolphin................................................... 0 518 518
Southern right-whale dolphin.................................... 0 291 291
Risso's dolphin................................................. 0 195 195
False killer whale.............................................. 0 291 291
Killer whale.................................................... 0 184 184
Long-finned pilot whale......................................... 0 789 789
Short-finned pilot whale........................................ 0 368 368
Pygmy sperm whale............................................... 1 166 167
Hourglass dolphin............................................... 3 394 397
Hector's dolphin................................................ 0 1 1
Spectacled porpoise............................................. 0 21 21
New Zealand fur seal............................................ 0 2141 2141
New Zealand sea lion............................................ 0 98 98
Southern elephant seal.......................................... 0 69 69
Leopard seal.................................................... 0 35 35
----------------------------------------------------------------------------------------------------------------
Note: NMFS does not authorize the estimated takes shown in the territorial sea.
\1\ Includes additional 25 percent contingency for potential additional survey operations and additional 25
percent contingency to account for uncertainties in density estimates.
NMFS does not anticipate that serious injury or mortality will
occur as a result of L-DEO's planned surveys, even in the absence of
mitigation. As discussed in the Potential Effects section, non-auditory
physical effects, stranding, and vessel strike are not expected to
occur.
We authorize a limited number of instances of Level A harassment of
21 marine mammal species (Tables 10, 11, 12 and 13). However, we
believe that any PTS incurred in marine mammals as a result of the
planned activity would be in the form of only a small degree of PTS,
not severe hearing impairment, and would be unlikely to affect the
fitness of any individuals, because of the constant movement of both
the Langseth and of the marine mammals in the project 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 Langseth's
approach due to the vessel's relatively low speed when conducting
seismic surveys. We expect that the majority of takes would be in the
form of short-term Level B behavioral harassment in the form of
temporary avoidance of the area or decreased foraging (if such activity
were occurring), reactions that are considered to be of low severity
and with no lasting biological consequences (e.g., Southall et al.,
2007).
Potential impacts to marine mammal habitat are discussed in the
Federal Register notice of the proposed IHA (82 FR 45116; September 27,
2017) and are summarized below. 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.
Prey species are mobile and are broadly distributed throughout the
[[Page 56148]]
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 planned project area.
As described above, the take estimates shown in Tables 10, 11, 12
and 13 have been revised slightly since we published the notice of the
proposed IHA in the Federal Register (82 FR 45116; September 27, 2017).
We have fully considered these revised take estimates in our negligible
impact analysis. Additionally, the acoustic ``footprint'' of the
planned surveys is small relative to the ranges of the marine mammals
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 planned survey area.
The 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 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 mitigation.
The ESA-listed marine mammal species under our jurisdiction that
are likely to be taken by the planned surveys include the southern
right, sei, fin, blue, and sperm whale (listed as endangered) and the
South Island Hector's dolphin (listed as threatened). We authorize a
very limited amount of take for these species (Tables 10, 11, 12 and
13), relative to their population sizes, therefore we do not expect
population-level impacts to any of these species. The other marine
mammal species that may be taken by harassment during the planned
surveys 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 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 L-DEO's planned 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.
In summary and as described above, the following factors primarily
support our determination that the impacts resulting from this activity
are not expected to adversely affect the marine mammal species or
stocks through effects on annual rates of recruitment or survival:
No serious injury or mortality is anticipated or
authorized;
The anticipated impacts of the planned activity on marine
mammals would primarily be temporary behavioral changes due to
avoidance of the area around the survey vessel;
The number of instances of PTS that may occur are expected
to be very small in number (Tables 10, 11, 12 and 13). 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 planned surveys to avoid exposure to sounds from the activity;
The planned project area does not contain known 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 planned
surveys would be temporary and spatially limited; and
The 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 monitoring and mitigation
measures, NMFS finds that the total marine mammal take from the planned
activity will have a negligible impact on all affected marine mammal
species or stocks.
Small Numbers
As noted above, only small numbers of incidental take may be
authorized under Section 101(a)(5)(D) of the MMPA for specified
activities other than military readiness activities. The MMPA does not
define small numbers; so, in practice, where estimated numbers are
available, NMFS compares the number of individuals taken to the most
appropriate estimation of abundance of the relevant species or stock in
our determination of whether an authorization is limited to small
numbers of marine mammals. Additionally, other qualitative factors may
be considered in the analysis, such as the temporal or spatial scale of
the activities. Tables 10, 11, 12 and 13 provide numbers of take by
Level A harassment and Level B harassment authorized. These are the
numbers we use for purposes of the small numbers analysis.
The numbers of marine mammals that we authorize to be taken would
be considered small relative to the relevant populations (less than 12
percent for all species) for the species for which abundance estimates
are available. No known current worldwide or regional population
estimates are available for ten species under NMFS' jurisdiction that
could be incidentally taken as a result of the planned surveys: the
pygmy right whale; pygmy sperm whale; True's beaked whale; short-finned
pilot whale; false killer whale; bottlenose dolphin; short-beaked
common dolphin; southern right whale dolphin; Risso's dolphin; and
spectacled porpoise.
NMFS has reviewed the geographic distributions and habitat
preferences of these species in determining whether the numbers of
takes authorized herein are likely to represent small numbers. Pygmy
right whales have a circumglobal distribution and occur throughout
coastal and oceanic waters in the Southern Hemisphere (between 30 to
55[deg] South) (Jefferson et al., 2008). Pygmy sperm whales occur in
deep waters on the outer continental shelf and slope in tropical to
temperate waters of the Atlantic, Indian, and Pacific Oceans. True's
beaked whales occur in the Southern hemisphere from the western
Atlantic Ocean to the Indian Ocean to the waters of southern Australia
and possibly New Zealand (Jefferson et al., 2008). False killer whales
generally occur in deep offshore tropical to temperate waters (between
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50[deg] North to 50[deg] South) of the Atlantic, Indian, and Pacific
Oceans (Jefferson et al., 2008). Southern right whale dolphins have a
circumpolar distribution and generally occur in deep temperate to sub-
Antarctic waters in the Southern Hemisphere (between 30 to 65[deg]
South) (Jefferson et al., 2008). Short-finned pilot whales are found in
warm temperate to tropical waters throughout the world, generally in
deep offshore areas (Olson and Reilly, 2002). Bottlenose dolphins are
distributed worldwide through tropical and temperate inshore, coastal,
shelf, and oceanic waters (Leatherwood and Reeves 1990, Wells and Scott
1999, Reynolds et al. 2000). Spectacled porpoises are believed to have
a range that is circumpolar in the sub-Antarctic zone (with water
temperatures of at least 1-10 [deg]C) (Goodall 2002). The Risso's
dolphin is a widely-distributed species, inhabiting primarily deep
waters of the continental slope and outer shelf (especially with steep
bottom topography), from the tropics through the temperate regions in
both hemispheres (Kruse et al. 1999). The short-beaked common dolphin
is an oceanic species that is widely distributed in tropical to cool
temperate waters of the Atlantic and Pacific Oceans (Perrin 2002), from
nearshore waters to thousands of kilometers offshore.
Based on the broad spatial distributions and habitat preferences of
these species relative to the areas where the planned surveys are
planned to occur, NMFS concludes that the authorized take of these
species likely represent small numbers relative to the affected
species' overall population sizes, though we are unable to quantify the
take numbers as a percentage of population.
Based on the analysis contained herein of the planned activity
(including the mitigation and monitoring measures) and the anticipated
take of marine mammals, NMFS finds that small numbers of marine mammals
will be taken relative to the population size of the affected species.
Unmitigable Adverse Impact Analysis and Determination
There are no relevant subsistence uses of the affected marine
mammal stocks or species implicated by this action. Therefore, NMFS has
determined that the total taking of affected species or stocks will not
have an unmitigable adverse impact on the availability of such species
or stocks for taking for subsistence purposes.
Endangered Species Act
Section 7(a)(2) of the Endangered Species Act of 1973 (ESA: 16
U.S.C. 1531 et seq.) requires that each Federal agency insure that any
action it authorizes, funds, or carries out is not likely to jeopardize
the continued existence of any endangered or threatened species or
result in the destruction or adverse modification of designated
critical habitat. To ensure ESA compliance for the issuance of IHAs,
NMFS consults internally, 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 authorizing the
incidental take of six species of marine mammals which are listed under
the ESA (the southern right, sei, fin, blue, and sperm whale and South
Island Hector's dolphin). Under section 7 of the ESA, we initiated
consultation with the NMFS OPR Interagency Cooperation Division for the
issuance of this IHA. In October, 2017, the NMFS OPR Interagency
Cooperation Division issued a Biological Opinion with an incidental
take statement, which concluded that the issuance of the IHA was not
likely to jeopardize the continued existence of the southern right,
sei, fin, blue, and sperm whale and South Island Hector's dolphin. The
Biological Opinion also concluded that the issuance of the IHA would
not destroy or adversely modify designated critical habitat for these
species.
Authorization
NMFS has issued an IHA to the L-DEO for the potential harassment of
small numbers of 38 marine mammal species incidental to marine
geophysical surveys in the southwest Pacific Ocean, provided the
previously mentioned mitigation, monitoring and reporting requirements
are incorporated.
Dated: November 21, 2017.
Donna Wieting,
Director, Office of Protected Resources, National Marine Fisheries
Service.
[FR Doc. 2017-25516 Filed 11-24-17; 8:45 am]
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