[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
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North Island 2-D survey North Island 3-D survey South Island 2-D survey
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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.
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* 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: http://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: http://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
[[Page 56149]]
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]
BILLING CODE 3510-22-P