[Federal Register Volume 78, Number 161 (Tuesday, August 20, 2013)]
[Notices]
[Pages 51147-51169]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2013-20310]
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DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
RIN 0648-XC563
Takes of Marine Mammals Incidental to Specified Activities;
Taking Marine Mammals Incidental to Marine Seismic Survey in the
Chukchi Sea, Alaska
AGENCY: National Marine Fisheries Service (NMFS), National Oceanic and
Atmospheric Administration (NOAA), Commerce.
ACTION: Notice; issuance of an incidental take authorization.
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SUMMARY: In accordance with the Marine Mammal Protection Act (MMPA)
regulations, notification is hereby given that NMFS has issued an
Incidental Harassment Authorization (IHA) to TGS-NOPEC Geophysical
Company ASA (TGS) to take, by harassment, small numbers of marine
mammals incidental to a marine 2-dimensional (2D) seismic survey
program in the Chukchi Sea, Alaska, during the 2013 Arctic open-water
season.
DATES: Effective August 14, 2013, through October 31, 2013.
ADDRESSES: Inquiry for information on the incidental take authorization
should be addressed to P. Michael Payne, Chief, Permits and
Conservation Division, Office of Protected Resources, National Marine
Fisheries Service, 1315 East-West Highway, Silver Spring, MD 20910. A
copy of the application containing a list of the references used in
this document, NMFS' Environmental Assessment (EA), Finding of No
Significant Impact (FONSI), and the IHA may be obtained by writing to
the address specified above, telephoning the contact listed below (see
FOR FURTHER INFORMATION CONTACT), or visiting the Internet at: http://www.nmfs.noaa.gov/pr/permits/incidental.htm#applications.
Documents cited in this notice may be viewed, by appointment,
during regular business hours, at the aforementioned address.
FOR FURTHER INFORMATION CONTACT: Shane Guan, Office of Protected
Resources, NMFS, (301) 427-8401 or Brad Smith, NMFS, Alaska Region,
(907) 271-3023.
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 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.
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.''
Section 101(a)(5)(D) of the MMPA established an expedited process
by which citizens of the U.S. can apply for an authorization to
incidentally take small numbers of marine mammals by harassment.
Section 101(a)(5)(D) establishes a 45-day time limit for NMFS review of
an application followed by a 30-day public notice and comment period on
any proposed authorizations for the incidental harassment of marine
mammals. Within 45 days of the close of the comment period, NMFS must
either issue or deny the authorization.
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''].
Summary of Request
On December 3, 2012, NMFS received an application from TGS
requesting an authorization for the harassment of small numbers of
marine mammals incidental to conducting an open-water 2D seismic survey
in the Chukchi Sea off Alaska. After addressing comments from NMFS, TGS
modified its application and submitted a revised application on April
1, 2013, and a revised marine mammal monitoring and mitigation plan on
April 15, 2013, with additional clarification on May 7, 2013. TGS'
activities discussed here are based on its April 1, 2013, IHA
application and April 15, 2013, marine mammal monitoring and mitigation
measures.
Description of the Specified Activity
TGS proposes to conduct approximately 9,600 km of marine 2D seismic
surveys along pre-determined lines in U.S. waters and international
waters of the Chukchi Sea (Figure 1 of TGS' IHA application) during the
2013 open water season. The purpose of the seismic program is to gather
geophysical data using a 3,280 in\3\ seismic source array and an 8,100-
m long hydrophone solid streamer towed by the seismic vessel. Results
of the 2D seismic program would be used to identify and map potential
hydrocarbon-bearing formations and the geologic structures that
surround them.
Approximately 35 days of seismic operations are expected to occur
over a period of about 45-60 days in U.S. Chukchi Sea. In addition, up
to 33 days of seismic operations may occur in international waters
(depending on ice and weather conditions). Seismic operations are
proposed to occur along pre-determined track lines at speeds of about
four to five knots. Seismic operations would be conducted up to 24
hours per day as possible except as potentially needed for shut-down
mitigation for marine mammals. The full 3,280 in\3\ airgun array would
only be firing during seismic acquisition operations on and near the
end and start of survey lines; during turns and transits between
seismic lines, a single ``mitigation'' airgun (60 in\3\ or smaller) is
proposed to be operated.
Two vessels would be used during the survey: (1) a seismic
operations vessel that would tow the seismic source array hydrophone
solid streamer, and (2) a
[[Page 51148]]
smaller vessel that will be used to search for marine mammals and scout
for ice and other navigation hazards ahead of the seismic vessel. In
the event of an emergency, the scout vessel may be used to support the
seismic vessel. In this extraordinary circumstance, all seismic
activity will cease since the scout vessel will no longer be devoted to
monitoring the exclusion zones.
The seismic vessel will tow a compressed-air seismic source array
of 28 Bolt 1900 LLXT airguns with a total discharge volume of 3,280
in\3\. The airguns range in volume from 40 in\3\ to 300 in\3\ and are
arranged in a geometric lay-out of three sub-arrays that will be towed
approximately 200 m behind the vessel at a depth of 6 m. The seismic
source would discharge every 25 m (82 ft) or approximately every 10
seconds. Additional details regarding seismic acquisition parameters
are provided in TGS' IHA application. To ascertain whether the seismic
source array is operating correctly, the full volume will be enabled
for 1 km from the start of every line (i.e., a run in). To ensure full
fold data acquisition the vessel will require a 4 km run out at the
conclusion of each line. TGS states that gravity and magnetic data will
also be passively acquired during the survey by measuring gravity and
magnetic variations while traversing the lines (no acoustics are
involved with these methods).
The acoustic source level of the proposed 3,280 in\3\ seismic
source array was predicted using JASCO's airgun array source model
(AASM) based on data collected from three sites chosen in the project
area by JASCO. Water depths at the three sites were 17, 40, and 100 m.
JASCO applied its Marine Operations Noise Model (MONM) to estimate
acoustic propagation of the proposed seismic source array and the
associated distances to the 190, 180 and 160 dB (rms) re 1 [mu]Pa
isopleths. The resulting isopleths modeled for the 180 and 190 dB (rms)
re 1 [mu]Pa exclusion zone distances for cetaceans and pinnipeds,
respectively, differed with the three water depths. An additional 10
percent distance buffer was added by JASCO to these originally modeled
distances to provide larger, more protective exclusion zone radii
distances that will be adhered to during the project (Table 1).
The estimated distances to the 190, 180 and 160 dB re 1[mu]Pa (rms)
isopleths for the single 60 in\3\ airgun (the largest single airgun
that would be used as a ``mitigation'' gun) were measured by JASCO
during a monitoring sound source verification (SSV) study conducted for
Statoil in 2010 in the Chukchi Sea during the open water season of 2010
(Blees et al. 2010). Results indicated that the distance to the 190 dB
isopleth was 13 m, the 180 dB isopleth distance was 68 m, and the 160
dB isopleth distance was 1,500 m (all dB (rms) re 1 [mu]Pa).
Table 1--Modeled Distances in (Meters) to Received Sound Levels for the TGS' 3,280 in \3\ Airgun Array in Waters
With Three Different Depths in the Chukchi Sea
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Received sound level (dB re 1 [mu]Pa rms)
Water depths (m) -------------------------------------------------------------------------------
190 180 160
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17-40........................... 930............... 2,200....................... 8,500
40-100.......................... 920............... 2,500....................... 9,900
>100............................ 430............... 2,400....................... 15,000
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Both vessels would use industry-standard echosounder/fathometer
instruments to continuously monitor water depth for navigation purposes
while underway. These instruments are the same as those used aboard all
large vessels to obtain information on water depths and potential
navigation hazards for vessel crews during routine navigation
operations. Navigation echosounders direct a single, high-frequency
acoustic signal that is focused in a narrow beam directly downward to
the sea floor. The reflected sound energy is detected by the
echosounder instrument which then calculates and displays water depth
to the user. Typical source levels of these types of navigational
echosounders are generally 180-200 dB re 1 [mu]Pa at 1 m.
One navigational echosounder would be used by the seismic vessel
and another one will be used by the scout vessel. The echosounder used
by the seismic vessel will consist of a downward-facing single-beam
(Kongsberg EA600) that operates at frequencies of 18 to 200 kHz (output
power 1-2 kilowatt [kW]). Associated pulse durations are 0.064 and
4.096 milliseconds (ms) long and repetition frequency of the pulse
(i.e., the ping rate) is related to water depth. In shallow water, the
highest pulse repetition frequency is about 20 pings per second. The
scout vessel will use a Furuno 292 echosounder that operates at a
frequency of 28 and 88 kHz. The highest ping rate in shallow water is
12 pings per second.
Dates, Duration and Action Area
TGS plans to conduct its 2D seismic surveys in both the U.S.
Chukchi Sea and international waters through October 31, 2013. Seismic
operations are anticipated to occur for about 35 days over a period of
45-60 days in U.S. waters and up to about 33 days in international
waters. Operations in U.S. waters are expected to be complete no later
than October 5, 2013. However, poor weather, ice conditions, equipment
repair, etc., would likely delay or curtail operations. Thus, this
extended period allows flexibility in proposed operational dates,
contingent on such conditions. Specific dates and durations of project
activities are listed below in chronological order, but are contingent
on weather and ice, etc.
The seismic operations are proposed to occur in U.S. and
international waters of the Chukchi Sea between about 70-77[deg] N and
154-165[deg] W (Figure 1 of TGS' IHA application). Up to approximately
6,088 km of seismic operations with the full sound source are planned
to be conducted in U.S. waters as follows, which include 5,973 km of
pre-plot lines plus approximately 115 km for 1-km run-in and 5-km run-
out between seismic lines. In addition, approximately 1,556 km with the
single 60 in\3\ (or smaller) mitigation airgun are planned to be
conducted during turns and transits between lines. Approximately 3,691
km of seismic operations with the full seismic source as follows are
planned to be conducted in international waters, which include 3,631 km
of pre-plot lines plus about 60 km of 1-km run-in and 5-km run-out
between pre-plot lines. In addition, approximately 812 km with the
single 60 in\3\ (or smaller) mitigation airgun are planned to be
conducted during turns and transits between seismic lines. Most of the
total approximately 9,600 km of seismic lines occur in water 40-100 m
deep (82% or 7,890 km), followed by waters >100 m deep (14% or 1,320
km) and waters <40 m deep (4% or 390 km).
Comments and Responses
A notice of NMFS' proposal to issue an IHA to TGS was published in
the Federal Register on June 12, 2013 (78 FR 35508). That notice
described, in
[[Page 51149]]
detail, TGS' activity, the marine mammal species that may be affected
by the activity, and the anticipated effects on marine mammals and the
availability of marine mammals for subsistence uses. During the 30-day
public comment period, NMFS received three comment letters from the
following: the Marine Mammal Commission (Commission); the Alaska Eskimo
Whaling Commission (AEWC); the North Slope Borough; the Alaska
Wilderness League (AWL), Center for Biological Diversity, Earthjustice,
Greenpeace, International Fund for Animal Welfare, Natural Resources
Defense Council, Northern Alaska Environmental Center, Ocean
Conservation Research, Oceana, Redoil, and Sierra Club (collectively
``AWL''), and two private citizens.
Any comments specific to TGS' application that address the
statutory and regulatory requirements or findings NMFS must make to
issue an IHA are addressed in this section of the Federal Register
notice.
Impacts Analysis
Comment 1: A private citizen states that NMFS may not issue the IHA
because it kills marine animals.
Response: As discussed in detail in the Federal Register notice for
the proposed IHA and in this document, the potential effects to marine
mammals from TGS' 2D seismic surveys would be Level B behavioral
harassment of small numbers of marine mammals in the project vicinity,
and no injury, serious injury, or mortality is expected. In addition,
no injury, serious injury, or mortality to marine mammal is authorized
by NMFS under this IHA.
Comment 2: The AEWC noted that on page 35516 of the Federal
Register notice for the proposed IHA, NMGS stated that ``though
temporary diversions of the swim path of migrating whales have been
documented, the whales have generally been observed to resume their
initial migratory route.'' The AEWC argues that there is no research
support migrating bowhead whales return to their normal migratory path
following deflection.
Response: NMFS acknowledges that the above statement made in the
Federal Register notice was somewhat misleading. NMFS has corrected the
statement to read ``though temporary diversions of the swim path of
migrating whales have been documented, the whales have generally been
observed to continue their migration via a deflected migratory route.''
Comment 3: The AEWC states that NMFS also needs to point out the
potential for whales to become skittish--changing their swim speeds,
breathing rates, and other migratory behavior--when affected by the
proposed open-water seismic surveys and vessel noise, even when they do
not deflect from their migratory path.
Response: NMFS is aware of the potential effects of whales becoming
skittish when exposed to seismic surveys and vessel noise, and has
incorporated this information in this document.
Comment 4: The NSB states that the distances estimated for the 190
and 180 dB zones seem reasonable but the 160 dB zone may be
substantially low. The NSB points out that previous sound source
verifications (SSV) conducted in the Chukchi Sea measured distances of
~ 8,000 to ~ 13,500 m for the 160 dB zone in similar water depths as
proposed by TGS. The NSB requests that NMFS require applicants to
provide data from previous SSV tests in future applications, even those
conducted by other companies, as a check on the modeled estimates. The
NSB further states that NMFS should require TGS to provide some sort of
estimate of the possible variability in distances for each of the
isopleths.
Response: As stated in the Federal Register notice for the proposed
IHA, as well as in TGS' IHA application, the acoustic source levels of
the seismic source array and mitigation airgun were calculated using
JASCO's airgun array source model (AASM) based on data collected from
three sites chosen in the project area reported in SSV for Statoil in
2010 by JASCO (see TGS' IHA application Appendix C). Water depths at
the these three sites were 17, 40, and 100 m, and the modeled 160 dB
zones range from 8,500 to 15,000 m. The possible variability in
distances for the isopleths has been considered and the originally
modeled exclusion zones were expanded by 10 percent by JASCO to provide
larger, more protective exclusion zones.
Comment 5: The Commission requests NMFS provide stronger assurance
that the actual numbers of takes would be negligible by revising the
estimates to (1) incorporate some measure of uncertainty in that
estimate (e.g., upper and lower confidence limits) or (2) use maximum
estimated densities. The AWL also claims that NMFS density estimations
are arbitrary, and that maximum estimated densities should be used.
Response: As discussed in detail in the Federal Register notice for
the proposed IHA, TGS' 2D seismic survey areas include the U.S. Chukchi
Sea and the international waters north of 72[deg] N, where marine
mammal density is less certain, primarily due to lack of systematic
scientific surveys. Therefore, density estimates for the proposed
seismic survey area were based on two types of sources: (1) Dedicated
marine mammal abundance surveys for certain areas and species, and (2)
sightings of marine mammals observed from prior seismic surveys when
seismic airgun arrays were off. The latter data were used to calculate
marine mammal densities for areas with high uncertainties (because of
the lack of well designed, dedicated marine mammal surveys). Since
these latter data were based on a few opportunistic sightings, it was
not possible to perform a rigorous statistical analysis and derive
upper and lower confidence limits. In fact, some of these densities in
the north of 72[deg] N were actually based on marine mammal densities
south of 72[deg] N, which is considered protective because it over-
estimates take numbers.
In this case, NMFS has chosen to use the average density data of
marine mammal populations to calculate estimated take numbers because
these numbers are based on dedicated surveys and monitoring of marine
mammals in the vicinity of the proposed project area. ``Maximum
densities'' are typically the average densities multiplied by a factor
of 4 or 5, and the method of their derivation is not scientifically
justified and would likely result in an overestimate. For several
species whose average densities are too low to yield a take number due
to extra-limital distribution in the vicinity of the proposed Chukchi
Sea survey area, but whose chance occurrence has been documented in the
past, such as killer whales, narwhales, and harbor porpoises, NMFS
allotted a few numbers of these species to allow unexpected takes.
The negligible determination is based on analysis of the potential
effects of the specific activities (i.e., airgun impulses from TGS' 2D
seismic surveys) on marine mammals, as well as the effectiveness of the
required monitoring and mitigation measures to minimize such effects.
Although different marine mammal densities used for take calculation
may yield different take numbers, the result is not likely to change
the nature of potential effects. In addition, an inflated take number
based on ``maximum densities'' could lead to more takes being
authorized. Finally, based on prior year marine mammal monitoring
reports from Arctic seismic surveys, it is well documented that the
numbers of marine mammals (modeled and corrected to account for animals
not observed) exposed to noise levels above harassment thresholds were
always
[[Page 51150]]
lower than take numbers calculated based on average densities.
Comment 6: The NSB states that beluga whales from both the Chukchi
Sea stock and Beaufort Sea stock will be found in TGS' proposed seismic
survey area. The NSB further points out that the Chukchi Sea stock will
certainly be there throughout the summer and the Beaufort Sea stock
will migrate through the Chukchi Sea during autumn migration in
September and October. The NSB states that it is unlikely that PSOs
will see belugas from the vessels because the animals are very
sensitive to anthropogenic sounds. The NSB states that TGS should be
required to have a monitoring technique that will allow them to observe
belugas in the far field (i.e., beyond the visual observers view). In
addition, citing TGS' IHA application, the NSB points out that although
it is true that most observations of belugas tend to be near the shore,
the entire Beaufort Sea stock of beluga whales migrates south through
the Chukchi Sea. The NSB further states that satellite tagged belugas
from the Beaufort Sea stock migrate south through the Chukchi Sea far
offshore in some cases.
Response: While the Beaufort Sea stock beluga whales do migrate
through the Chukchi during their fall migration, NMFS considers it
unlikely TGS would encounter this population during its open-water
seismic survey because of the temporal and spatial design of the
survey. TGS plans on surveying the Alaskan Chukchi first in August when
the Beaufort Sea stock beluga whales will be in their Beaufort Sea
summer area. Although recent tagging studies showed that Beaufort Sea
stock beluga whales migrate through deep water during their fall
westward migration, the majority of the animals are expected to stay
below 72[deg] N in September (Hauser et al. 2013). In October, most
Beaufort Sea beluga whales will have moved farther south/west along the
Russian Chukchi Sea (Hauser et al. 2013). The TGS survey area during
September and October will be moved farther north offshore in
international waters above 72[deg] N. Therefore, it is not likely the
survey would encounter Beaufort Sea stock beluga whales during the
latter portion of the surveys.
Regarding far field monitoring of marine mammals, as stated in the
Federal Register notice for the proposed IHA, visual monitoring from a
scout vessel at the perimeter of the exclusion zone as well as towed
passive acoustic monitoring will be implemented.
Comment 7: Citing TGS' IHA application that harbor porpoises are
unlikely to occur in significant numbers within the seismic survey
area, the NSB argues that this is a misstatement. Citing Industry's
Joint Monitoring Program Reports for the Chukchi and Beaufort Seas and
90-day monitoring reports since 2006, the NSB points out that in recent
industry surveys, harbor porpoises are one of the most commonly seen
cetaceans in the Chukchi Sea. The NSB further points out that harbor
porpoises are among the most commonly sighted cetaceans in Table 3 of
TGS' IHA application. The NSB states that TGS must consider this
cetacean in their assessment of possible impacts to marine mammals from
the proposed seismic survey.
Response: While NMFS does not disagree with the NSB assessment
regarding the occurrence of harbor porpoises in Chukchi Sea, it is also
important to note that the area where harbor porpoise occurrences were
recorded in the Industry's Joint Monitoring Program Report for the
Chukchi and Beaufort Seas are limited to within the U.S. Beaufort Sea,
while much of TGS' proposed 2D seismic survey area is located in
international waters farther north and offshore, which is not likely a
habitat for the harbor porpoise, which occur more often inshore.
Further, while TGS may have inaccurately characterized the abundance of
harbor porpoises in the U.S. Chukchi Sea, where part of its 2D seismic
surveys would occur, NMFS conducted its own analyses in determine the
potential impacts to all marine mammal species within both U.S. Chukchi
Sea and international waters. Finally, as the NSB also noticed, the
harbor porpoise densities presented in Table 3, which were used to
calculate take estimates, actually used information from 90-day
monitoring reports submitted in prior years by holders of incidental
take authorizations, and took into consideration the high occurrence of
this species in the U.S. Chukchi Sea.
Comment 8: Citing TGS' IHA application, the NSB points out that
TGS' statement that its activities are ``expected to be temporary and
minor, with no long-term impacts to individuals or populations based on
available studies'' is misleading. The NSB pointed out that no one has
examined the long-term effects from seismic exposure; therefore no data
exist to evaluate the long-term effects.
Response: NMFS agrees with the NSB's assessment that the long-term
effects on marine mammals from seismic surveys are still largely
unknown, therefore, the statement made by TGS in its IHA application
needs to be viewed with caution. Nevertheless, in making the
determination to issue the IHA to TGS, NMFS conducted its own analyses
and evaluation. A more detailed discussion on potential anthropogenic
noise impacts on marine mammals and marine mammal habitat can be found
in the Federal Register notice for the proposed IHA, as well as in this
document.
Comment 9: The Commission requests that NMFS require TGS to revise
its take estimates such that adjustment factors do not reduce the
estimated densities for waters north of 72[deg] N latitude without
additional scientific basis for those adjustments. The NSB also pointed
out that satellite tagging of beluga whales indicated many of the
whales traveled to north of 72[deg] N. The NSB questions how TGS is
going to monitor and assess possible impacts to beluga whales.
Response: NMFS believes that this comment is due to the language
presented in TGS' original IHA application. The initial IHA application
submitted by TGS in November 2012 contained an adjustment factor of
0.01 for gray whales, 0.10 for bowhead and beluga whales, and ringed
and bearded seals for areas above 72[deg] N. This IHA application,
though not published for public comment as NMFS did not consider it
complete, was submitted to a peer review panel, which included members
from the Commission and the NSB, for review and comment. After
receiving NMFS comments and recommendations, TGS subsequently modified
its analysis and submitted a revised IHA application on April 1, 2013.
The revised IHA application included ``upper-adjusted density
estimates'', which is virtually the same adjustment proposed in TGS'
initial IHA application, and ``lower-adjusted density estimates'',
which only make an adjustment for gray whales north of 72[deg] N by a
factor of 0.2. No adjustments were made for bowhead and beluga whales
and bearded and ringed seals north of 72[deg] N.
In NMFS calculation of take estimates, the ``lower-adjusted density
estimates'' were used for adjusting the gray whale numbers because
reported gray whale distribution in the Chukchi Sea normally does not
extend much north of 72[deg] N during summer/fall (Clarke and Ferguson
2010). This northernmost peripheral boundary area is thus expected to
have very low gray whale densities. In addition, by fall when TGS
enters into the international waters after completing surveys in the
U.S. Chukchi Sea, most gray whales will have migrated south of the
project area north of 72[deg] N (Rice and Wolman 1971; Allen and
Angliss 2011).
[[Page 51151]]
Comment 10: The NSB states that Table 4 of TGS' IHA application
showed that all adjustments would lower the densities of marine mammals
north of 72[deg] N as all the values are <=1. The NSB also notes that
the footnote (*) suggests the densities may increase but because the
factors are one or less the densities will all actually decrease. The
NSB asks if this is appropriate for all species, especially belugas.
The NSB further notes that belugas have a mark for a footnote (**) but
there is no corresponding discussion associated with the footnote.
Response: As discussed in the previous response to comment, the
adjustment factors under ``high adjustment'' were carried over from
TGS' previous IHA application, and were not used in density estimates.
Regarding the ``low adjustment'', there is only one adjustment factor
(0.2) for gray whales, which is explained in the previous response to
comment. Several species such as humpback, fin, minke, and killer
whales, harbor porpoises, and ribbon and spotted seals, are not
expected to occur north of 72[deg] N, therefore NMFS does not believe
they would be taken north of 72[deg] N. For the rest of the marine
mammal species, including beluga whales and bowhead whales, no
adjustment was made in take calculation. As far as the extra footnote
for beluga whale in Table 4 of TGS' IHA application, TGS responded that
the corresponding notes to the footnote for beluga should read ``the
beluga population estimate for the E Chukchi Sea is based on the
minimum population estimate, as this is the only and most current up to
date population estimate per the NMFS Stock Assessment Report.'' The
note was accidentally omitted.
Comment 11: The NSB notes that TGS should be congratulated for
providing a range of estimates of numbers of marine mammals that may be
exposed to seismic sounds. The NSB further states that this approach is
an improvement over a single point estimate that is typically provided
in an IHA application.
Response: NMFS agrees with the NSB assessment that presenting a
range of estimates of numbers of marine mammal that may be exposed to
anthropogenic sounds is a better approach than a single number
estimate.
Comment 12: The NSB states that the approach for calculating the
size of the ensonified area could lead to a negative bias in animals
exposed to seismic sound because there are areas of overlap. The NSB
notes that since most marine mammals will not stay stationary in one
location of the Chukchi Sea over extended periods of time, the areas of
overlap should be counted twice.
Response: NMFS does not completely agree with the NSB's assessment.
While there is a potential for negative bias in calculating animals
exposed to seismic sound where the take zones overlap but the
calculation is based on multiplying the ensonified area by marine
mammal densities, such cases are only applicable to 3D seismic surveys
and site clearance and shallow hazard surveys where the survey track
lines are much closer together. For TGS' 2D seismic survey, the
ensonified areas are established along each track line, which took into
consideration areas where track lines crisscross and thus the
overlapping areas are accounted for. Therefore, even though marine
mammals may move in/out the survey area, the entire ensonified areas
along the track lines were included in the calculation of exposures.
Comment 13: The NSB and AWL claims that NMFS underestimated the
number of animals that would be harassed from TGS's survey because it
calculates harassment from TGS's proposed survey based on the exposure
of marine mammals to impulsive sounds at or above 160 dB. The AWL
states that this uniform approach to harassment does not take into
account known reactions of marine mammals in the Arctic to levels of
noise well below 160 dB. The NSB states that bowhead and beluga whales
respond to anthropogenic sound at lower levels, as low as or lower than
120 dB. Without citing specific research, the AWL claims that ``for
harbor porpoises, behavioral changes, including exclusion from an area,
can occur at received levels from 90-110 dB [near ambient level] or
lower,'' and beluga whales ``are known to alter their migration paths
in response to ice breaker noise at received levels as low as 80 dB
[quiet ambient level].'' The AWL further pointed out that NMFS
acknowledged the potential for behavioral disturbance to belugas at
distances of 10-20 km, and for bowhead whales to react to sound levels
lower than 160 dB.
Response: NMFS does not agree with NSB and AWL's assessment on
acoustic effects of marine mammals. Even though bowhead and beluga
whales have been observed to respond to anthropogenic sound levels as
low as 120 dB, as stated by the NSB, most likely those are non-impulse
sounds (such as noise from icebreaking) as NSB did not provide specific
description of characteristics of the noise. In general, marine mammals
tend to respond to short pulses at higher received levels than longer
non-pulse sound, hence the difference in NMFS current criteria of
different take thresholds.
In regards to the AWL's argument, first, the AWL did not provide a
reference on harbor porpoise behavioral responses and exclusion from an
area to received levels at 90-110 dB or lower, which is near the
ambient noise level. Second, for the beluga whale example at quiet
ambient level, although also not supported by a reference, such a
deviation could be attributed to noise exposure to continuous sound
(icebreaker), rather than exposure to seismic impulses. Additionally,
as TGS does not intend to use icebreakers during its operations,
statements regarding beluga reactions to icebreaker noise are not
relevant to this activity. Concerning the behavioral disturbance by
belugas at distances of 10-20 km, there was no mention of received
level, so it is irrelevant to the AWL's argument concerning 160 dB
received noise levels.
Additionally, as stated in the past, NMFS does not believe that
minor course corrections during a migration will always equate to
``take'' under the MMPA. This conclusion is based on controlled
exposure experiments conducted on migrating gray whales exposed to the
U.S. Navy's low frequency sonar (LFA) sources (Tyack 2009). When the
source was placed in the middle of the migratory corridor, the whales
were observed deflecting around the source during their migration.
However, such minor deflection is considered not to be biologically
significant. To show the contextual nature of this minor behavioral
modification, recent monitoring studies of Canadian seismic operations
indicate that when not migrating, but involved in feeding, bowhead
whales do not move away from a noise source at an SPL of 160 dB.
Therefore, while bowheads may avoid an area of 20 km (12.4 mi) around a
noise source, when that determination requires a post-survey computer
analysis to find that bowheads have made a 1 or 2 degree course change,
NMFS believes that does not rise to a level of a ``take.'' NMFS
therefore continues to estimate ``takings'' under the MMPA from impulse
noises, such as seismic, as being at a distance of 160 dB (re 1
[mu]Pa). Although it is possible that marine mammals could react to any
sound levels detectable above the ambient noise level within the
animals' respective frequency response range, this does not mean that
such animals would react in a biologically significant way. According
to experts on marine mammal behavior, the degree of reaction which
constitutes a ``take,'' i.e.,
[[Page 51152]]
a reaction deemed to be potentially biologically significant or that
could potentially disrupt the migration, breathing, nursing, breeding,
feeding, or sheltering, etc., of a marine mammal is complex and context
specific, and it depends on several variables in addition to the
received level of the sound by the animals. These additional variables
include, but are not limited to, other source characteristics (such as
frequency range, duty cycle, continuous vs. impulse vs. intermittent
sounds, duration, moving vs. stationary sources, etc.); specific
species, populations, and/or stocks; prior experience of the animals
(naive vs. previously exposed); habituation or sensitization of the
sound by the animals; and behavior context (whether the animal
perceives the sound as predatory or simply annoyance), etc. (Southall
et al. 2007).
NMFS is in the process of developing revised acoustic criteria and
thresholds for different sources, including seismic sources. The
revised acoustic criteria will be peer-reviewed and made available for
public comment. Until that process is complete, it is not appropriate
to apply the new criteria and thresholds in any incidental take
authorization. Instead, NMFS will continue its longstanding practice of
considering specific modifications to the acoustic criteria and
thresholds currently employed for incidental take authorizations only
after providing the public with an opportunity for review and comment
and responding to the comments.
Comment 14: The AWL states that uncertainty precludes conclusions
regarding take number and potential impacts. The AWL further states
that NMFS must consider the extent of missing information about
ecosystems in the Chukchi Sea, especially considering the large
footprint of TGS' proposed survey.
Response: Although NMFS agrees that it would be desirable to obtain
additional information about the Chukchi Sea ecosystem and regional
populations of marine mammals, NMFS has sufficient information to
support its analysis of the potential impacts of TGS's proposed marine
surveys on wildlife. As required by the MMPA implementing regulations
at 50 CFR 216.102(a), NMFS has used the best scientific information
available in assessing the level of take and whether the impacts would
be negligible. The Federal Register notice for the proposed IHA, NMFS
EA for the issuance of IHAs to take marine mammals incidental to open-
water marine and seismic surveys in 2013, and this document all provide
detailed analysis using the best available scientific information that
enables NMFS to make the required determinations. In addition, the
required monitoring and mitigation measures prescribed in the IHA NMFS
issued to TGS will further reduce any potential impacts of the proposed
marine surveys on marine mammals.
Comment 15: The AWL states that NMFS may not issue the IHA because
it has not negated the possibility of serious injury from TGS's
airguns. Further, the AWL noted that 18 years ago, NMFS once stated
that permanent hearing loss qualifies as serious injury (60 FR 28381,
May 31, 1995). A private citizen further states that the marine survey
is ``massive deadly'' to marine mammals.
Response: NMFS does not agree with the private citizen and AWL's
assessment. NMFS was able to make a preliminary determination in the
Federal Register for the proposed IHA to TGS to take marine mammals
incidental to its open-water marine surveys. In addition, NMFS'
preliminary determination states that the potential effects would be
Level B behavioral harassment of small numbers of marine mammals in the
project vicinity, and no injury, serious injury, or mortality is
expected.
Concerning the AWL's comments on NMFS 1995 proposed rule to
implement the process to apply for and obtain an IHA, NMFS stated that
authorizations for harassment involving the ``potential to injure''
would be limited to only those that may involve non-serious injury (60
FR 28379; May 31, 1995). While the Federal Register notice cited by the
commenters states that NMFS considered PTS to be a serious injury (60
FR 28379; May 31, 1995), our understanding of anthropogenic sound and
the way it impacts marine mammals has evolved since 1995, and NMFS no
longer considers PTS to be a serious injury. NMFS has defined ``serious
injury'' in 50 CFR 216.3 as ``. . . any injury that will likely result
in mortality.'' There are no data that suggest that PTS would be likely
to result in mortality, especially the limited degree of PTS that could
hypothetically be incurred through exposure of marine mammals to
seismic airguns at the level and for the duration that are likely to
occur in this action.
Further, as stated several times in this document and previous
Federal Register notices for seismic activities, there is no empirical
evidence that exposure to pulses of airgun sound can cause PTS in any
marine mammal, even with large arrays of airguns (see Southall et al.
2007). PTS is thought to occur several decibels above that inducing
mild temporary threshold shift (TTS), the mildest form of hearing
impairment (a non-injurious effect). NMFS concluded that cetaceans and
pinnipeds should not be exposed to pulsed underwater noise at received
levels exceeding, respectively, 180 and 190 dB re 1 [mu]Pa (rms). The
established 180- and 190-dB re 1 [mu]Pa (rms) criteria are the received
levels above which, in the view of a panel of bioacoustics specialists
convened by NMFS before TTS measurements for marine mammals started to
become available, one could not be certain that there would be no
injurious effects, auditory or otherwise, to marine mammals.
Additionally, NMFS has required monitoring and mitigation measures to
negate the possibility of marine mammals being seriously injured or
killed as a result of TGS's activities. In the proposed IHA, NMFS
determined that TGS's activities are unlikely to even result in TTS.
Based on this determination and the explanation provided here, PTS is
also not expected. Therefore, an IHA is appropriate.
Comment 16: The AWL claims that NMFS' take estimates of 30,000
ringed seals, close to 1,500 gray whales, 800 bowhead whales, and 400
beluga whales do not meet MMPA's ``small number'' requirement. The AWL
further claims that NMFS underestimated the Level B takes in the
proposed IHA.
Response: NMFS does not agree with the AWL's assessment. First, as
mentioned in the Federal Register notice for the proposed IHA and in
this document, the estimated takes of the bowhead, gray, and beluga
whales and ringed seals represent 7.53%, 7.13%, 11.11%, and 14.36% of
their populations, respectively. As described in the Negligible Impact
and Small Numbers Analysis and Determination section of this document,
NMFS considers the number of authorized takes small. In addition, the
percent population of bowhead whale takes is further reduced to 4.70%
based on the most recent surveys and on the recommendation by
scientists from the NSB (see Response to Comment 39).
As discussed in detail in the Negligible Impact and Small Numbers
Analysis and Determination section of this document, all takes from
TGS' proposed open-water seismic surveys are expected to be Level B
behavioral harassment, in the form of startle behavior or vacating the
area for the short duration of time when the seismic airgun is firing
in the area. Animals could also change their behavior patterns during
this short duration, but are expected to resume their normal activities
and reoccupy the area as soon
[[Page 51153]]
as the vessels move away. Additionally, since a portion of the proposed
open-water seismic survey is planned in offshore waters far north above
72[deg] N, it is expected to be outside the gray whale habitat. In
addition, the mitigation and monitoring measures (described previously
in the Federal Register notice for the proposed IHA) included in the
IHA are expected to further reduce any potential disturbance to marine
mammals.
Comment 17: The AWL claims that NMFS' negligible impact finding is
unjustified.
Response: NMFS does not agree with the AWL's assessment. First, as
discussed in the Negligible Impact and Small Numbers Analysis and
Preliminary Determination section of the Federal Register notice for
the proposed IHA, based on rigorous analyses, TGS' proposed 2D seismic
surveys in the Chukchi Sea are expected to result in takes of small
numbers of marine mammals in the form of Level B behavioral harassment.
Animals exposed to airgun noises are expected to show brief startle
reactions or to temporarily vacate the seismic site. No injury, serious
injury, or mortality is expected, and none is authorized. Please also
see Responses to Comments 15 and 16 for additional justification.
Comment 18: The AWL states that NMFS must consider potential
effects from masking and stress.
Response: NMFS agree that potential acoustic masking and stress
caused by anthropogenic sources could negatively affect marine mammal
fitness and survival. The potential impacts from masking and stress by
seismic surveys are considered and discussed in detail in the Federal
Register notice for the proposed IHA. In this case, masking effects of
pulsed sounds on marine mammal calls and other natural sounds are
expected to be limited. Some whales continue calling in the presence of
seismic pulses (e.g., Richardson et al. 1986; McDonald et al. 1995;
Greene et al. 1999a, 1999b; Nieukirk et al. 2004; Smultea et al. 2004;
Holst et al. 2005a, 2005b, 2006; Dunn and Hernandez 2009). In addition,
marine mammals are thought to be able to compensate to some degree for
masking by adjusting their acoustic behavior such as shifting call
frequencies, and increasing call volume and vocalization rates, as
discussed in the Federal Register notice for the proposed IHA (e.g.,
Miller et al. 2000; Parks et al. 2007; Di Iorio and Clark 2009; Parks
et al. 2010).
Although not much is known about potential stress to marine mammals
from exposure from seismic surveys, the TGS' proposed 2D survey in the
Chukchi Sea is short in duration, and will not stay in one area.
Therefore, as analyzed in the Federal Register notice for the proposed
IHA, the potential effects are expected to be negligible.
Mitigation
Comment 19: AEWC requested that NMFS include the following
provisions of the 2013 CAA in Section 6(d) of the IHA issued to TGS:
Section 202(a) and (c): Com-Center General Communications Scheme;
Section 204: Standardized Log Books; Section 302: Barge and Transit
Vessel Operations; Section 402: Sound Signature Tests; Section 501:
General provisions for Avoiding Interference with Bowhead Whales or
Subsistence Whale Hunting Activities; Section 502(b): Limitations on
Geophysical Activity in the Chukchi Sea; Section 505: Termination of
Operations and Transit Through the Bering Strait; and Title VI,
Sections 601 and 602: Late Season Seismic Operations.
Response: NMFS has incorporated the above provisions of the 2013
CAA into the IHA issued to TGS, as these measures will help ensure
there is no unmitigable adverse impact on the availability of affected
species or stock(s) for subsistence uses.
Comment 20: The Commission requested that NMFS specify reduced
vessel speeds of 9 knots or less when weather conditions or darkness
reduce visibility.
Response: NMFS worked with TGS and included the speed limitation
requested by the Commission in the IHA as a mitigation measure for
vessel movement.
Comment 21: A private subsistence user comments that since seals
diving to the bottom to feed on benthic organisms in deep water can
stay down for an hour or more, NMFS should extend the visual monitoring
of the exclusion zone to 30 minutes or longer before ramping up, after
a shutdown due to a pinniped entering the zone.
Response: NMFS is aware that pinnipeds are able to dive for long
periods. However, in the case of TGS' 2D seismic survey, the required
condition for ramping up seismic airguns after a shutdown triggered by
pinniped presence is that (1) the pinniped is visually observed to have
moved out of the exclusion zone, or (2) 15 minutes have passed since
the last time the pinniped is seen. The time duration of 15 minutes is
not based on the depth to which the pinniped can dive. Rather, it is
based on the relatively small 190-dB exclusion zone for pinnipeds, and
the speed of the seismic vessel, which is typically between 4 and 5
knots. As presented in the Federal Register notice for the proposed
IHA, the modeled 190-dB exclusion zones range from 430-930 m, depending
on depth. Assuming that the radius of the zone is 930 m, and the source
vessel is moving at a speed of 4 knots (7.4 km/hr), then in 15 minutes,
the vessel will be at a location 1.85 km from where the pinniped was
initially sighted. Therefore, NMFS believes that 15 minutes is a long
enough duration to wait prior to safely ramping up seismic airguns
after a shutdown caused by the presence of a pinniped.
Comment 22: The AWL states NMFS should include provisions in the
IHA that restrict TGS's operations based on geographic location, and/or
time of year, such as restricting activity in certain areas, including
subsistence use areas, areas of high productivity or diversity; areas
that are important for feeding, migration, or other parts of the life
history of species; or areas of biogenic habitat, structure-forming
habitat, or habitat for endangered or threatened species.
Response: While processing the proposed IHA, NMFS worked with TGS
and conducted extensive analysis on the areas where TGS's proposed
open-water marine surveys would occur. The areas TGS proposed to have
its proposed marine surveys are analyzed in the proposed IHA process,
during the section 7 consultation under the ESA, as well as under the
NEPA analysis conducted during preparation of the EA. However, NMFS did
not find that further restriction is needed given that no areas of high
productivity or diversity, areas that are important for feeding and
migration, or critical habitat for endangered or threatened species
were found. Nevertheless, certain time and area restrictions are
included in the IHA to minimize potential impacts on subsistence
activities which are consistent with the CAA TGS has signed. These time
and area restrictions are:
Vessels should remain as far offshore as weather and ice
conditions allow, and at least five miles offshore during transit,
From August 31 to October 31 vessels in the Chukchi Sea or
Beaufort Sea shall remain at least 20 miles offshore of the coast of
Alaska from Icy Cape in the Chukchi Sea to Pitt Point on the east side
of Smith Bay in the Beaufort Sea whether in transit or engaging in
activities in support of oil and gas operations unless ice conditions
or an emergency that threatens the safety of the vessel or crew
prevents compliance with this requirement,
[[Page 51154]]
Beginning September 15, and ending with the close of the
fall bowhead whale hunt, if Wainwright, Pt. Lay, or Pt. Hope intend to
whale in the Chukchi Sea, no more than two geophysical activities
employing geophysical equipment will occur at any one time in the
Chukchi Sea. During the fall bowhead whale hunt, geophysical equipment
will not be used within 30 miles of any point along the Chukchi Sea
coastline. Industry participants will contact the Whaling Captains'
Associations of each village to determine if a village is prepared to
whale and will notify the AEWC of any response, and
All Industry participant vessels shall complete operations
in time to allow such vessels to complete transit through the Bering
Strait to a point south of 59 degrees North latitude no later than
November 15, 2013.
Comment 23: The AWL states that NMFS should examine imposing
requirements for the use of new technology that could reduce the
footprint of seismic exploration. The AWL cited an expert conference in
February in Silver Spring, Maryland, by NMFS on alternative
technologies for offshore energy production and requested that NMFS
consider (1) Mandating the use of marine vibroseis or other
technologies in some or all of the survey area; (2) mandating the
testing of marine vibroseis in a pilot area, precedent to a decision to
permit seismic activity, with an obligation to accrue data on
environmental impacts; (3) deferring the permitting of surveys in part
or all of the survey area until effective mitigative technologies, such
as marine vibroseis, become available; (4) providing incentives for
TGS's use of these technologies as was done for passive acoustic
monitoring systems; and (5) exacting funds from TGS to support
accelerated mitigation research in this area.
Response: First, the February workshop (not an ``expert
conference'') in Silver Spring, Maryland, titled Quieting Technologies
for Reducing Noise during Seismic Surveying and Pile Driving, was
convened by BOEM, not NMFS. The goals of the workshop, as stated in the
Web site of the workshop, were to (1) Review and examine recent
developments (existing, emerging, and potential) in quieting
technologies for seismic surveying, whether proposed or in development;
(2) identify the requirements for operation and limitations for using
these technologies; (3) evaluate data quality and cost-effectiveness of
these technologies as compared to that from existing marine acoustic
technologies; (4) identify the acoustic characteristics of new
technologies in varying environments compared to that from existing
technologies; (5) examine potential environmental impacts from these
technologies; (6) identify which technologies, if any, provide the most
promise for full or partial traditional use and specify the conditions
that might warrant their use (e.g., specific limitations to water
depth, use in Marine Protected Areas, etc.); and (7) identify next
steps, if appropriate, for the further development of these
technologies, including potential incentives for field testing. Most of
these technologies are still in research and development stages and
have not been field tested. The workshop provided a forum for
discussion and evaluation of such technologies, including vibroseis.
NMFS supports and encourages both the development and use of
technologies that will reduce impacts to marine mammals and other
marine species. These alternative technologies will likely be adopted
for use to replace some subset of future seismic survey activities once
their development is further along and their environmental impacts,
especially as compared to seismic airguns, are better understood.
However, NMFS does not believe it can currently mandate the use of such
technologies.
Monitoring
Comment 24: The Commission requests NMFS only authorize an in-
season adjustment in the size of the exclusion and/or disturbance zones
if the size(s) of the estimated zones are determined to be too small.
The Commission states that the purpose of SSV is to ensure protection
of marine mammals, and one way to reduce risk to marine mammals would
be to only allow expansion of the exclusion and/or disturbance zones.
Response: NMFS does not agree with the Commission's recommendation.
While it may seem to be more protective to increase the size of the
exclusion zone, if the effectiveness of visual-based marine mammal
monitoring remains the same, the actual result may not be an increase
in protection. For example, when the SSV suggests that the exclusion
and/or disturbance zones are smaller than the ones modeled and
monitoring still focuses on the larger modeled zones, it is likely that
the effectiveness of marine mammal monitoring could be reduced as the
area to be monitored would be larger than necessary. In addition,
larger than realistic exclusion zones would cause unnecessary power-
down and shutdowns, which could increase the total duration of the
marine surveys, and cause unnecessary impacts to the marine
environment.
Comment 25: The Commission requests NMFS require TGS to monitor for
marine mammals 30 minutes before, during, and 30 minutes after survey
operations and other activities have ceased.
Response: TGS is required to monitor for marine mammals 30 minutes
before, during, and 30 minutes after survey operations and other
activities have ceased.
Comment 26: The Commission requests NMFS encourage TGS to deploy
additional protected species observers to (1) increase the probability
of detecting all marine mammals in or approaching the Level A and B
harassment zones and (2) assist in the collection of data on
activities, behaviors, and movements of marine mammals around the
source.
Response: NMFS agrees that an adequate number of PSOs is critical
to ensure complete coverage in visual monitoring and implementing
mitigation measures. While it is reasonable to conclude that additional
PSOs would increase detection capability to a certain degree, the
number of PSOs that can be stationed on vessels is limited by the
available berth spaces. TGS plans to have 5 PSOs onboard the survey
vessel and 4 onboard the scout vessel, and will have 100% monitoring
coverage during all periods of survey operations in daylight. In
addition, each PSO is limited to maximum of 4 consecutive hours per
watch and maximum of 12 hours of watch time per day. NMFS believes that
the number of PSOs onboard is adequate given the limited space
available on the survey vessel.
Comment 27: The NSB notes that towed PAM will be used for marine
mammal monitoring during TGS' 2D seismic survey. The NSB states that
PAM is still in the research and development phase, and that it is not
clear whether it will provide useful data. In addition, the NSB states
that since the PAM will be towed by the scout vessel thus presumably
reducing the maneuverability of the scout vessel. The NSB further
states that the scout vessel would have a more difficult time visually
monitoring the safety and behavioral impact zones with the streaming
towed array.
Response: NMFS is aware of the technical challenges involved in
towed PAM for marine mammal monitoring. Nevertheless, given the needs
for marine mammal monitoring at far-field beyond visual observation,
and the technological progresses made in the
[[Page 51155]]
past few years regarding towed PAM, it is worth the efforts to require
towed PAM as an extra modality to monitor marine mammal presence in the
seismic survey area, and to enhance visual monitoring. Towed PAM has
been used in past IHAs issued by NMFS for marine mammal monitoring in
the Arctic (e.g., open-water seismic survey by StatOil in the Chukchi
Sea in 2010), and the results indicated more acoustic detections than
visual detections, and acoustic detections have led to visual
detections of marine mammals. Regarding towed PAM for TGS' 2D seismic
survey, NMFS worked with the applicant and its acoustic contractor and
carefully reviewed all technical aspects of the acoustic monitoring
design and methods. The reason that PAM will be conducted from the
scout vessel is to decouple the PAM array from the seismic streamer and
airgun arrays. In addition, because the purpose of the towed PAM is to
expand the monitoring to the far-field by positioning them
approximately 2 km ahead of the seismic vessel, it makes sense that the
PAM array be deployed off the scout vessel. The design will not reduce
the maneuverability of the scout vessel since the scout vessel is
positioned to be approximately 2 km ahead of the seismic vessel for
far-field monitoring. More details of the towed PAM design and
discussion are described in TGS' 4MP.
Comment 28: The NSB states that because the towed PAM is not a
proven technique for monitoring marine mammals in the vicinity of a
seismic survey in the Arctic, NMFS should require TGS to collect
acoustic data using bottom mounted instruments. The NSB states that TGS
should deploy at least several instruments in the northern areas of
their proposed seismic survey area.
Response: As discussed above, NMFS is aware of the technical
challenges involved in implementing towed PAM for marine mammal
monitoring. The justification and improvement in implementing the towed
PAM as an effective tool for marine mammal monitoring is discussed in
Response to Comment 27. As discussed in the Federal Register notice for
the proposed IHA, NMFS discussed extensively with TGS ways to improve
the far-field marine mammal monitoring. As a result, upon further
investigation and conversations with both JASCO and Bio-Waves by TGS,
as well as further research into past Arctic marine mammal monitoring
results conducted with towed-PAM, NMFS and TGS agree that utilizing a
well-designed towed-PAM system would be a better choice under this
circumstance to provide enhanced marine mammal monitoring beyond
exclusion zones in a real time basis, as well as using acoustic data
for limited relative abundance and distribution analysis, and possibly
limited insights on impacts to marine mammals.
NMFS also studied other PAM methodologies suggested by the peer-
review panel. First, concerning deploying fixed bottom mounted
instruments, TGS states that it worked with other operators but was not
able to find a collaborator to participate in long-term acoustic
monitoring due to the short-term nature of the proposed survey.
Regarding real-time acoustic monitoring with a fixed buoy, TGS stated
that it conducted an evaluation of this option and discussed the
possibility with Cornell University's Bioacoustical Research Program
concerning its real-time marine acoustic recording unit (MARU), but
decided that the technology is still in the research and development
stage. When the fact that the equipment is still in the developmental
stages is considered in combination with the increased cost of this
technology, TGS believes that the downsides of using fixed buoys
outweigh the potential benefits and that towed PAM is a more effective
solution. Therefore, NMFS considers in this case that a towed PAM is a
reasonable alternative for passive acoustic monitoring.
Comment 29: The AWL claims that NMFS' proposed mitigation measures
are ineffective and do not negate the potential for serious injury.
Citing the example of ION Geophysical's 90-day monitoring report, the
AWL points out the difficulty of monitoring these zones at distances
greater than 2.2 miles. The AWL further states that since the very
large size of the 180-dB exclusion zone could extend to 2.5 km (1.5 mi)
from the sound source, depending on water depth, marine mammals could
be injured. The AWL also points out that the proposed monitoring
measures for behavioral harassment were also inadequate as the 160 dB
zone could extend to 15 km from the source. Further, the AWL states
that the Open-water peer review panel reviewing TGS's proposed
activities also noted serious limitations of visual monitoring, and
that ``PSOs on the scout vessel will only be able to monitor a small
portion of the 160 dB zone.'' Finally, the AWL quotes ION's 90-day
report as saying ``nights with fog, no ambient light, or heavy seas
made observations nearly impossible.''
Response: NMFS recognizes the limitations of visual monitoring as
distance increases. However, TGS's proposed open-water seismic survey
would employ a scout vessel to supplement the visual monitoring of the
exclusion zone at a distance of approximately 2 km in front of the
source vessel, to ensure that the exclusion zone is free of marine
mammals during the survey. In addition, NMFS recognizes that 2.5 km
(1.5 mi) is a large distance for vessel monitoring, however, based on
prior marine mammal monitoring reports, this distance is well within
the line of sight and can be effectively monitored by experienced PSOs.
Furthermore, towed PAM will be implemented to supplement marine mammal
monitoring to further increase the chance of detecting marine mammals
in the survey vicinity.
Concerning far field monitoring of the 160-dB zone, NMFS recognizes
the limitations of visual monitoring, but again, towed PAM will provide
information on marine mammals in the vicinity. It is likely that towed
PAM designed for TGS' seismic survey will be able to localize marine
mammals in the far field beyond exclusion zones, as discussed in detail
in the Federal Register notice for the proposed IHA.
In addition, NMFS also recognizes the limitations of visual
monitoring in darkness and other inclement weather conditions.
Therefore, in the IHA issued to TGS, NMFS required that no seismic
airgun can be ramped up when the entire exclusion zones are not
visible. However, TGS's operations will occur in an area where periods
of darkness do not begin until early September. Beginning in early
September, there will be approximately 1-3 hours of darkness each day,
with periods of darkness increasing by about 30 min each day. By the
end of the survey period, there will be approximately 8 hours of
darkness each day. These conditions provide PSOs favorable monitoring
conditions for most of the time.
Comment 30: The AWL states that the use of PAM does not remedy
AWL's perceived flaws in the mitigation regime, and the AWL is not
clear whether or how towed PAM will be used to improve implementation
of the exclusion zones. The AWL further states NMFS provided less
detail about how the PAM system will work by stating that details and
specifications of the equipment will be determined at a later date once
TGS has identified a contractor for the system.
Response: Concerning the effectiveness of using towed PAM to
supplement marine mammal monitoring, and the effectiveness of
implementing towed PAM, please refer
[[Page 51156]]
to Response to Comment 27. The utilization of towed PAM to improve
implementation of the exclusion zones is discussed in detail in the
Federal Register notice for the proposed IHA and in TGS' 4MP. In
summary, using towed PAM to supplement marine mammal visual detection
has been required by NMFS in the past for various marine seismic and
geophysical activities and it has proven to be effective. Specifically,
there are far more acoustic detections than visual detection of marine
mammals, and many visual detections were based on initial acoustic
detection of marine mammals in the project vicinity. In addition, for
the TGS' seismic survey, marine mammal localization by towed PAM is
also proposed by using target motion analysis. With this method, it is
possible with a single towed hydrophone array to obtain a localization
to vocalizing animals given certain assumptions. Although due to the
linear alignment of hydrophones, there is a left/right ambiguity that
cannot be resolved without turning the tow vessel, this ambiguity is
not a concern for mitigation during the seismic survey because the
exclusion zones are circular and would encompass both sides of the
hydrophones. Therefore, the distance to the calling animal is the same
on the right and left side of the vessel.
Although at the time when the Federal Register notice for the
proposed IHA was published NMFS did not have specific information
concerning the design of the towed PAM, specific requirements for an
effective towed PAM were analyzed and requested. For example, the towed
PAM system shall be able to monitor marine mammal occurrence within 160
dB isopleths, and shall minimize the interferences from flow noise by
equipping the system with pre-amplifier filters that are ``tuned'' to
reduce low-frequency flow and vessel noise. Detailed discussion on
these requirements and specifications are provided in the Federal
Register notice for the proposed IHA and in TGS' 4MP.
Comment 31: Citing ION's error in its initial exclusion zone
measurements, the AWL states that sound measurements used to estimate
the size of safety radii from which animals should be excluded can
easily be miscalculated. The AWL further requests NMFS require sound
source verification before any activities commence to ensure no similar
errors and resulting takes occur during TGS' proposed activities.
Response: Although NMFS recognizes the error made by ION's
contractor during the sound source verification measurement and the
radius of the 180-dB exclusion was originally estimated less than it
was measured to be, NMFS does not agree with AWL's speculation that
sound measurements used to estimate the size of exclusion zones can be
``easily miscalculated.'' The ION incident was not due to
miscalculation. It was due to human error in data handling and is
preventable. NMFS has subsequently discussed this with ION and its
contractor to make sure that rigorous checks and verification are
performed to ensure no error in data handling.
NMFS agrees with the AWL that SSV will be conducted before TGS
commences its seismic surveys in the Chukchi Sea.
Subsistence Issues
Comment 32: The NSB requests NMFS require TGS to sign the CAA with
the Alaska Eskimo Whaling Commission (AEWC).
Response: The signing of a CAA is not a requirement to obtain an
IHA. The CAA is a document that is negotiated between and signed by the
industry participant, AEWC, and the Village Whaling Captains'
Associations. Although the contents of a CAA may inform NMFS' ``no
unmitigable adverse impact'' determination for bowhead and beluga
whales, the signing of it is not a requirement. Nevertheless, TGS
signed the 2013 CAA and NMFS incorporated all relevant measures that
will help to ensure no unmitigable adverse impacts to subsistence
harvest activities into the IHA issued to TGS.
Comment 33: The Commission recommends that NMFS encourage the
development of conflict avoidance agreements that reflect the interests
of all potentially affected communities and co-management organizations
and account for potential adverse impacts on all marine mammal species
taken for subsistence.
Response: TGS signed a Conflict Avoidance Agreement (CAA) with the
Alaska native whaling communities to ensure that there is no
unmitigable adverse impacts to subsistence whaling activities from its
proposed 2D seismic survey in the Chukchi Sea. For marine mammal
species other than bowhead whales, TGS developed a POC and engaged with
all potentially affected communities and co-management organizations to
ensure that the potential effects to subsistence activities can be
mitigated. In addition, TGS developed a marine mammal monitoring and
mitigation plan to make sure that there will be no unmitigable impacts
to subsistence use of all marine mammal species by the native
communities. Finally, NMFS has rigorously reviewed TGS' POC and the 4MP
and provided additional recommendations (e.g., passive acoustic
monitoring) to further reduce any adverse effects. NMFS has
subsequently made a determination that TGS' 2013 open-water 2D seismic
survey will not have unmitigable adverse impacts to subsistence use of
any marine mammal species. Neither the MMPA nor its implementing
regulations require an independent legal agreement between TGS and any
subsistence use representative. TGS has already ensured there will be
no unmitigable adverse impact to subsistence uses.
Comment 34: The AEWC and NSB point out that currently there are 11
villages that take bowhead whales, not 10 as described in the Federal
Register notice for the proposed IHA. The AEWC further asks NMFS to
update the discussion of Barrow whaling to acknowledge the increasing
importance of the fall hunt.
Response: NMFS appreciates the additional new information on the
current subsistence whaling activities and clarifying the role of the
fall bowhead whale hunt. NMFS' analyses provided in the Federal
Register notice for the proposed IHA was based on historical data as
the most recent data from the same season may not be available at the
time of analysis. NMFS has incorporated this information into the
subsistence impact analysis in this document.
Comment 35: Citing the Federal Register notice for the proposed IHA
that NMFS states that the provisions in the POC ``should minimize
impacts to subsistence hunters,'' the AEWC argues that ``should'' and
``minimize'' simply has no place in the statutory analysis. The AEWC
states that NMFS must determine that the proposed activities ``will not
have an unmitigable adverse impact on the availability of such species
or stock for taking for subsistence uses.''
Response: NMFS agrees with the AEWC's point and considers that the
sentence in the ``Unmitigable Adverse Impact Analysis and Preliminary
Determination'' section of the Federal Register notice did not
accurately convey NMFS analyses on subsistence affects. NMFS
subsequently corrected the sentence to read ``TGS has adopted a spatial
and temporal strategy for its Chukchi Sea open-water seismic surveys
that will have no unmitigable impacts to subsistence hunters'' under
the ``Unmitigable Adverse Impact Analysis and Determination'' section
of this document.
[[Page 51157]]
NEPA Concern
Comment 36: The AEWC and AWL state that NMFS must address the
potential cumulative effects of multiple concurrent seismic operations
in the Chukchi and Beaufort Seas.
Response: NMFS prepared an EA to analyze and address cumulative
impacts of other oil and gas activities planned for the Arctic Ocean.
The oil and gas related activities in the U.S. Arctic in 2013 include
this activity and Shell's open-water marine surveys in the Chukchi Sea.
Seismic survey activities in the Canadian and Russian Arctic occur in
different geophysical areas, therefore, they are not analyzed under the
NMFS 2013 EA. Other appropriate factors, such as Arctic warming,
military activities, and noise contributions from community and
commercial activities were also considered in NMFS' 2013 EA. Please
refer to that document for further discussion of cumulative impacts.
Comment 37: The AWL notes that NMFS is in the middle of preparing a
programmatic EIS for Arctic Ocean oil and gas exploration, and states
that NEPA prohibits piecemeal approvals while a programmatic EIS
process is ongoing, except under strictly prescribed circumstances not
found here. The AWL further states that if NMFS were to allow TGS'
activities to go forward pending completion of the EIS, NMFS risks
undermining the overarching aim of the programmatic EIS process to
establish appropriate standards for future oil and gas activities that
address and mitigate potential cumulative effects of the activities.
Response: NMFS does not agree with the AWL statement. While the
analysis contained in the Final EIS will apply more broadly to Arctic
oil and gas operations, NMFS' issuance of an IHA to TGS for the taking
of several species of marine mammals incidental to conducting its open-
water marine survey in the Chukchi Sea in 2013, as analyzed in the EA,
is not expected to significantly affect the quality of the human
environment. In the 2013 Arctic EA, NMFS included a rigorous analysis
on cumulative effects of all activities currently occurring in the
Arctic. TGS's surveys are not expected to significantly affect the
quality of the human environment because of the limited duration and
scope of operations.
ESA Concern
Comment 38: The AWL states that although NMFS has completed a
programmatic biological opinion for Arctic oil and gas activities, it
must also thoroughly analyze the impacts of the specific activities
authorized here including future impacts. The AWL further states that
in order to comply with the ESA, this site-specific analysis must
include an incidental take statement specifying the number and type of
takes expected.
Response: For the issuance of the IHA to TGS, NMFS' Permits and
Conservation Division initiated consultation with NMFS Alaska Regional
Office (AKRO) Protected Resources Division under section 7 of the ESA
on the issuance of an IHA to TGS under section 101(a)(5)(D) of the MMPA
for this activity. The consultation took into consideration the
specific activities proposed to be authorized and all aspects of
current and future impacts to the species. A Biological Opinion was
issued on June 19, 2013, which concludes that issuance of the IHA is
not likely to jeopardize the continued existence of the ESA-listed
marine mammal species. In addition, analysis by NMFS AKRO showed that
humpback whale will not be affected, therefore, no take was authorized.
NMFS will issue an Incidental Take Statement under this Biological
Opinion which contains reasonable and prudent measures with
implementing terms and conditions to minimize the effects of take of
listed species.
Miscellaneous
Comment 39: The NSB points out that the most recent bowhead
population estimates are: 12,631 from 2004 (Koski et al. 2010) and
16,892 for 2011 (Givens et al. 2013).
Response: NMFS appreciates NSB pointing out the most recent bowhead
population estimates and made corrections in the relevant section. With
the revised population estimates, the percentage of the Bering-Chukchi-
Beaufort Sea population of bowhead whales that could be taken by Level
B harassment is changed from 7.53% to 4.70%.
Comment 40: The NSB notes that TGS has proposed to coordinate with
state, federal and NSB divisions but has not discussed how they will
coordinate with other industry operators. The NSB points out that
Shell, ConocoPhillips and Statoil have an extensive monitoring program
in the Chukchi Sea, including passive acoustic monitoring (PAM). The
NSB points out that results from that PAM could provide useful
information about possible impacts from TGS' seismic operations. The
NSB requests NMFS require TGS to work with other industry partners who
are collecting useful data in the area where they are operating.
Response: As discussed in the Federal Register notice for the
proposed IHA, NMFS has discussed extensively with TGS on a variety of
techniques to improve its far field monitoring, including PAM using
ocean bottom mounted acoustic sensors. During the course of discussion,
TGS stated that it was in contact with other industry operators but was
not able to find a collaborator to participate in long-term acoustic
monitoring due to the short-term nature of its proposed survey.
Further, NMFS cannot legally require TGS to work with other industry
partners under the MMPA. Nevertheless, TGS is able to implement PAM
with towed acoustic arrays, as described in detail in the Federal
Register notice for the proposed IHA and in this document.
Comment 41: The Commission requested that NMFS allow sufficient
time between the close of the comment period and the issuance of an IHA
for NMFS to analyze, consider, and respond fully to comments received
and incorporate recommended changes, as appropriate--the applicable
statutory provision, section 101(a)(5)(D)(iii), anticipates that up to
45 days might be required. The Commission points out that the deadline
for comments on the proposed IHA is July 12, 2013, yet the IHA was
proposed to be issued on July 15, 2013. The Commission states that it
is concerned that the time between the close of the comment period and
the issuance of the IHA does not provide adequate opportunity for NMFS
to consider, provide adequate responses to, and incorporate any changes
prompted by comments from the Commission and the public.
Response: NMFS always fully reviews and considers comments
submitted by the Commission and the public, and works with the
applicant to incorporate such input as appropriate. In the case of the
TGS IHA, NMFS is actively working with the applicant on the scheduling
issue, and since the publication of the Federal Register notice for the
proposed IHA, TGS has indicated that its 2D seismic survey would
probably start in early August, thus giving NMFS extra time to complete
the process.
Description of Marine Mammals in the Area of the Specified Activity
The marine mammal species under NMFS jurisdiction most likely to
occur in the seismic survey area include eight cetacean species: beluga
whale (Delphinapterus leucas), harbor porpoise (Phocoena phocoena),
killer whale (Orcinus orca), bowhead whale (Balaena mysticetus), gray
whale (Eschrichtius robustus), minke whale
[[Page 51158]]
(Balaenoptera acutorostrata), fin whale (B. physalus), and humpback
whale (Megaptera novaeangliae), and four pinniped species, ringed
(Phoca hispida), spotted (P. largha), bearded (Erignathus barbatus),
and ribbon seals (Histriophoca fasciata).
The bowhead, fin, and humpback whales are listed as ``endangered'',
and the ringed and bearded seals are listed as ``threatened'' under the
Endangered Species Act (ESA) and as depleted under the MMPA. Certain
stocks or populations of gray and beluga whales and spotted seals are
also listed under the ESA, however, none of those stocks or populations
occur in the proposed activity area.
TGS' application contains information on the status, distribution,
seasonal distribution, and abundance of each of the species under NMFS
jurisdiction mentioned in this document. Please refer to the
application for that information (see ADDRESSES). Additional
information can also be found in the NMFS Stock Assessment Reports
(SAR). The Alaska 2012 SAR is available at: http://www.nmfs.noaa.gov/pr/sars/pdf/ak2012.pdf.
Potential Effects of the Specified Activity on Marine Mammals
Operating active acoustic sources such as airgun arrays,
navigational sonars, and vessel activities have the potential for
adverse effects on marine mammals. Potential effects from TGS' 2D
seismic survey on marine mammals in the Chukchi Sea are discussed in
the Federal Register (78 FR 35508; June 12, 2013) notice for the
proposed IHA. No changes have been made to the discussion contained in
this section of the Federal Register notice for the proposed IHA.
Anticipated Effects on Habitat
The primary potential impacts to marine mammal habitat are
associated with elevated sound levels produced by airguns and vessels
and their affects to marine mammal prey species. These potential
effects from TGS' 2D seismic survey are discussed in the Federal
Register (78 FR 35508; June 12, 2013) notice for the proposed IHA. No
changes have been made to the discussion contained in this section of
the Federal Register notice for the proposed IHA.
Potential Impacts on Availability of Affected Species or Stock for
Taking for Subsistence Uses
Subsistence hunting is an essential aspect of Inupiat Native life,
especially in rural coastal villages. The Inupiat participate in
subsistence hunting activities in and around the Chukchi Sea. The
animals taken for subsistence provide a significant portion of the food
that will last the community through the year. Marine mammals represent
on the order of 60-80% of the total subsistence harvest. Along with the
nourishment necessary for survival, the subsistence activities
strengthen bonds within the culture, provide a means for educating the
young, provide supplies for artistic expression, and allow for
important celebratory events.
Potential Impacts to Subsistence Uses
NMFS has defined ``unmitigable adverse impact'' in 50 CFR 216.103
as: ``. . . an impact resulting from the specified activity: (1) That
is likely to reduce the availability of the species to a level
insufficient for a harvest to meet subsistence needs by: (i) Causing
the marine mammals to abandon or avoid hunting areas; (ii) Directly
displacing subsistence users; or (iii) Placing physical barriers
between the marine mammals and the subsistence hunters; and (2) That
cannot be sufficiently mitigated by other measures to increase the
availability of marine mammals to allow subsistence needs to be met.''
(1) Bowhead Whales
TGS' planned seismic surveys would have no or negligible effects on
bowhead whale harvest activities. Noise and general activity associated
with seismic surveys and operation of vessels has the potential to
harass bowhead whales. However, though temporary diversions of the swim
path of migrating whales have been documented, the whales have
generally been observed to continue their migration via a deflected
migratory route. The proposed open-water seismic surveys and vessel
noise could affect subsistence hunts by placing the animals further
offshore or otherwise at a greater distance from villages thereby
increasing the difficulty of the hunt or retrieval of the harvest, or
creating a safety risk to the whalers. Further, whales have the
potential to become skittish--changing their swim speeds, breathing
rates, and other migratory behavior--when exposed to seismic and vessel
noise, even if they do not deflect, thus make hunting more difficult.
Eleven primary coastal Alaskan villages deploy whaling crews during
whale migrations. Around the TGS' proposed project area in the Chukchi
Sea, the primary bowhead hunting villages that could be affected are
Barrow, Wainwright, and Point Hope. Whaling crews in Barrow hunt in
both the spring and the fall (Funk and Galginaitis 2005). The primary
bowhead whale hunt in Barrow occurs during spring, while the fall hunt
is used to meet the quota and seek strikes that can be transferred from
other communities. In the spring, the whales are hunted along leads
that occur when the pack ice starts deteriorating. This tends to occur
between the first week of April through May in Barrow and the first
week of June in Wainwright, well before the proposed 2D seismic surveys
would be conducted. The Point Hope bowhead whale hunt occurs from March
to June. Whaling camps are established on the ice edge south and
southeast of Point Hope, 10 to 11 km (6 to 7 mi) offshore. However, due
to extremely dangerous and challenging ice conditions, along with
persistent strong westerly and southwesterly winds in 2013, the spring
bowhead whale subsistence hunt fell far below the subsistence needs
this year. Only four of the villages were able to take any whales:
Gambell landed two out of a quota of eight, Savoonga landed four out of
a quota of eight, and Pt. Hope landed five out of a quota of 10. Barrow
was able to land only one whale out of a quota of 22. The remaining
spring villages were unable to take any whales. As a result, the fall
hunting will be especially important, not only for Barrow and the
Beaufort Sea villages, but also for attempts out of Wainwright, Pt.
Lay, and possibly Pt. Hope. Nevertheless, the proposed seismic survey
would be conducted in the West of Point Barrow in the Chukchi Sea far
offshore.
(2) Beluga Whales
Belugas typically do not represent a large proportion of the
subsistence harvests by weight in the communities of Wainwright and
Barrow. Barrow residents hunt beluga in the spring (normally after the
bowhead hunt) in leads between Point Barrow and Skull Cliffs in the
Chukchi Sea primarily in April-June, and later in the summer (July-
August) on both sides of the barrier island in Elson Lagoon/Beaufort
Sea (MMS 2008), but harvest rates indicate the hunts are not frequent.
Wainwright residents hunt beluga in April-June in the spring lead
system, but this hunt typically occurs only if there are no bowheads in
the area. Communal hunts for beluga are conducted along the coastal
lagoon system later in July-August. Between 2005 and 2009, the annual
beluga subsistence take was 94 whales (Allen and Angliss 2012) among
both Wainwright and Barrow.
Belugas typically represent a much greater proportion of the
subsistence harvest in Point Lay and Point Hope. Point Lay's primary
beluga hunt occurs from mid-June through mid-July, but can sometimes
continue into August if
[[Page 51159]]
early success is not sufficient. Belugas are harvested in coastal
waters near these villages, generally within a few miles from shore.
However, the southern extent of TGS' proposed surveys is over 88 m to
the north of Point Lay, and much farther away from Point Hope.
Therefore NMFS considers that the surveys would have no or negligible
effect on beluga hunts.
(3) Seals
Seals are an important subsistence resource and ringed seals make
up the bulk of the seal harvest. Most ringed and bearded seals are
harvested in the winter or in the spring before TGS' 2013 activities
would commence, but some harvest continues during open water and could
possibly be affected by TGS' planned activities. Spotted seals are also
harvested during the summer. Most seals are harvested in coastal
waters, with available maps of recent and past subsistence use areas
indicating seal harvests have occurred only within 30-40 mi (48-64 km)
off the coastline. TGS does not plan to survey within 88 km (55 mi) of
the coast, which means that the proposed activities are not likely to
have an impact on subsistence hunting for seals.
As stated earlier, the proposed seismic survey would take place
between July and October. The proposed seismic survey activities would
be conducted in far offshore waters of the Chukchi Sea and away from
any subsistent activities. In addition, the timing of the survey
activities that would be conducted between July and October would
further avoid any spring hunting activities in Chukchi Sea villages.
Therefore, due to the time and spatial separation of TGS' proposed 2D
seismic surveys and the subsistence harvest by the local communities,
it is anticipated to have no effects on spring harvesting and little or
no effects on the occasional summer harvest of beluga whale,
subsistence seal hunts (ringed and spotted seals are primarily
harvested in winter while bearded seals are hunted during July--
September in the Beaufort Sea), or the fall bowhead hunt.
In addition, TGS has developed and proposes to implement a number
of mitigation measures (described in the next section) which include a
Marine Mammal Monitoring and Mitigation Plan (4MP), employment of
subsistence advisors in the villages, and implementation of a
Communications Plan (with operation of Communication Centers). TGS has
also prepared a Plan of Cooperation (POC) under 50 CFR 216.104 that
addresses potential impacts on subsistence seal hunting activities.
Finally, to ensure that there will be no conflict from TGS'
proposed open-water seismic surveys to subsistence activities, TGS
stated that it will maintain communications with subsistence
communities via the communication centers (Com and Call Centers) and
signed the Conflict Avoidance Agreement (CAA) with Alaska whaling
communities.
Mitigation Measures
In order to issue an incidental take authorization under Section
101(a)(5)(D) of the MMPA, NMFS must set forth the permissible methods
of taking pursuant to such activity, and other means of effecting the
least practicable adverse 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.
For the proposed TGS open-water marine 2D seismic surveys in the
Chukchi Sea, NMFS is requiring TGS to implement the following
mitigation measures to minimize the potential impacts to marine mammals
in the project vicinity as a result of its survey activities. The
primary purpose of these mitigation measures is to detect marine
mammals within, or about to enter designated exclusion zones and to
initiate immediate shutdown or power down of the airgun(s).
(1) Establishing Exclusion and Disturbance Zones
Under current NMFS guidelines, the ``exclusion zone'' for marine
mammal exposure to impulse sources is customarily defined as the area
within which received sound levels are >=180 dB (rms) re 1 [mu]Pa for
cetaceans and >=190 dB (rms) re 1 [mu]Pa for pinnipeds. These safety
criteria are based on an assumption that SPL received at levels lower
than these will not injure these animals or impair their hearing
abilities, but that at higher levels might have some such effects.
Disturbance or behavioral effects to marine mammals from underwater
sound may occur after exposure to sound at distances greater than the
exclusion zones (Richardson et al. 1995). Currently, NMFS uses 160 dB
(rms) re 1 [mu]Pa as the threshold for Level B behavioral harassment
from impulses noise.
The acoustic source level of the proposed 3,280 in\3\ seismic
source array was predicted using JASCO's airgun array source model
(AASM) based on data collected from three sites chosen in the project
area by JASCO. Water depths at the three sites were 17, 40, and 100 m.
JASCO applied its Marine Operations Noise Model (MONM) to estimate
acoustic propagation of the proposed seismic source array and the
associated distances to the 190, 180 and 160 dB (rms) re 1 [mu]Pa
isopleths relative to standard NMFS mitigation and monitoring
requirements for marine mammals. The resulting isopleths modeled for
the 180 and 190 dB (rms) re 1 [mu]Pa exclusion zone distances for
cetaceans and pinnipeds, respectively, differed with the three water
depths. An additional 10 percent distance buffer was added by JASCO to
these originally modeled distances to provide larger, more protective
exclusion zone radii. The modeled exclusion zones and zones of
influence are listed in Table 1.
These safety distances will be implemented at the commencement of
2013 airgun operations to establish marine mammal exclusion zones used
for mitigation. TGS will conduct sound source measurements of the
airgun array at the beginning of survey operations in 2013 to verify
the size of the various marine mammal exclusion zones. The acoustic
data will be analyzed as quickly as reasonably practicable in the field
and used to verify and adjust the marine mammal exclusion zone
distances. The mitigation measures to be implemented at the 190 and 180
dB (rms) sound levels will include power downs and shut downs as
described below.
(2) Vessel Related Mitigation Measures
These mitigation measures apply to all vessels that are part of the
Chukchi Sea seismic survey activities, including the supporting vessel.
Avoid concentrations or groups of whales by all vessels
under the direction of TGS. Operators of vessels should, at all times,
conduct their activities at the maximum distance possible from such
concentrations of whales.
Vessels in transit shall be operated at speeds necessary
to ensure no physical contact with whales occurs. If any vessel
approaches within 1.6 km (1 mi) of observed bowhead whales, except when
providing emergency assistance to whalers or in other emergency
situations, the vessel operator will take reasonable precautions to
avoid potential interaction with the bowhead whales by taking one or
more of the following actions, as appropriate:
[cir] Reducing vessel speed to less than 5 knots within 300 yards
(900 feet or 274 m) of the whale(s);
[cir] Steering around the whale(s) if possible;
[cir] Operating the vessel(s) in such a way as to avoid separating
members of
[[Page 51160]]
a group of whales from other members of the group;
[cir] Operating the vessel(s) to avoid causing a whale to make
multiple changes in direction; and
[cir] Checking the waters immediately adjacent to the vessel(s) to
ensure that no whales will be injured when the propellers are engaged.
Reduce vessel speed to 5 knots when weather conditions
require, such as when visibility drops, to avoid the likelihood of
injury to whales.
(3) Mitigation Measures for Airgun Operations
The primary role for airgun mitigation during the seismic surveys
is to monitor marine mammals near the airgun array during all daylight
airgun operations and during any nighttime start-up of the airguns.
During the seismic surveys PSOs will monitor the pre-established
exclusion zones for the presence of marine mammals. When marine mammals
are observed within, or about to enter, designated safety zones, PSOs
have the authority to call for immediate power down (or shutdown) of
airgun operations as required by the situation. A summary of the
procedures associated with each mitigation measure is provided below.
Ramp Up Procedure
A ramp up of an airgun array provides a gradual increase in sound
levels, and involves a step-wise increase in the number and total
volume of airguns firing until the full volume is achieved. The purpose
of a ramp up (or ``soft start'') is to ``warn'' cetaceans and pinnipeds
in the vicinity of the airguns and to provide time for them to leave
the area and thus avoid any potential injury or impairment of their
hearing abilities.
During the open-water survey program, the seismic operator will
ramp up the airgun arrays slowly. Full ramp ups (i.e., from a cold
start after a shut down, when no airguns have been firing) will begin
by firing a single airgun in the array (i.e., the mitigation airgun). A
full ramp up, after a shut down, will not begin until there has been a
minimum of 30 min of observation of the safety zone by PSOs to assure
that no marine mammals are present. The entire exclusion zone must be
visible during the 30-minute lead-in to a full ramp up. If the entire
exclusion zone is not visible, then ramp up from a cold start cannot
begin. If a marine mammal(s) is sighted within the safety zone during
the 30-minute watch prior to ramp up, ramp up will be delayed until the
marine mammal(s) is sighted outside of the exclusion zone or the
animal(s) is not sighted for at least 15-30 minutes: 15 minutes for
small odontocetes (harbor porpoise) and pinnipeds, or 30 minutes for
baleen whales and large odontocetes (including beluga and killer whales
and narwhal).
Use of a Small-Volume Airgun During Turns and Transits
Throughout the seismic survey, particularly during turning
movements, and short transits, TGS will employ the use of a small-
volume airgun (i.e., 60 in\3\ ``mitigation airgun''). The mitigation
airgun would be operated at approximately one shot per minute and would
not be operated for longer than three hours in duration during daylight
hours and good visibility. In cases when the next start-up after the
turn is expected to be during lowlight or low visibility, use of the
mitigation airgun may be initiated 30 minutes before darkness or low
visibility conditions occur and may be operated until the start of the
next sail line. The mitigation gun must still be operated at
approximately one shot per minute.
During turns or brief transits (e.g., less than three hours)
between seismic tracklines, one mitigation airgun will continue
operating. The ramp-up procedure will still be followed when increasing
the source levels from one airgun to the full airgun array. However,
keeping one airgun firing will avoid the prohibition of a ``cold
start'' during darkness or other periods of poor visibility. Through
use of this approach, seismic surveys using the full array may resume
without the 30 minute observation period of the full exclusion zone
required for a ``cold start''. PSOs will be on duty whenever the
airguns are firing during daylight, during the 30 minute periods prior
to ramp-ups.
Power-Down and Shut Down Procedures
A power down is the immediate reduction in the number of operating
energy sources from all firing to some smaller number (e.g., single
mitigation airgun). A shut down is the immediate cessation of firing of
all energy sources. The array will be immediately powered down whenever
a marine mammal is sighted approaching close to or within the
applicable safety zone of the full array, but is outside the applicable
safety zone of the single mitigation source. If a marine mammal is
sighted within or about to enter the applicable safety zone of the
single mitigation airgun, the entire array will be shut down (i.e., no
sources firing).
Poor Visibility Conditions
TGS plans to conduct 24-hour operations. PSOs will not be on duty
during ongoing seismic operations during darkness, given the very
limited effectiveness of visual observation at night (there will be no
periods of darkness in the survey area until mid-August). The
provisions associated with operations at night or in periods of poor
visibility include the following:
If during foggy conditions, heavy snow or rain, or
darkness (which may be encountered starting in late August), the full
180 dB exclusion zone is not visible, the airguns cannot commence a
ramp-up procedure from a full shut-down.
If one or more airguns have been operational before
nightfall or before the onset of poor visibility conditions, they can
remain operational throughout the night or poor visibility conditions.
In this case ramp-up procedures can be initiated, even though the
exclusion zone may not be visible, on the assumption that marine
mammals will be alerted by the sounds from the single airgun and have
moved away.
(4) Mitigation Measures for Subsistence Activities
Regulations at 50 CFR 216.104(a)(12) require IHA applicants for
activities that take place in Arctic waters to provide a Plan of
Cooperation (POC) or information that identifies what measures have
been taken and/or will be taken to minimize adverse effects on the
availability of marine mammals for subsistence purposes.
TGS has prepared a POC, which relies upon the Chukchi Sea
Communication Plans to identify the measures that TGS has developed in
consultation with North Slope subsistence communities and will
implement during its planned 2013 activities to minimize any adverse
effects on the availability of marine mammals for subsistence uses. The
POC describes important subsistence activities near the proposed survey
program and summarizes actions TGS has taken to inform subsistence
communities of the proposed survey activities; and measures it will
take to minimize adverse effects on marine mammals where proposed
activities may affect the availability of a species or stock of marine
mammals for arctic subsistence uses or near a traditional subsistence
hunting area.
TGS began stakeholder engagement by introducing the project to the
North Slope Borough (NSB) Planning Commission on October 25, 2012, and
it also met with the NSB Planning Director and other Barrow leadership.
In
[[Page 51161]]
December 2012, TGS met with Chukchi Sea community leaders at the
tribal, city, and corporate level in Barrow, Wainwright, Point Hope,
Point Lay, and Kotzebue. TGS also introduced the project to the Alaska
Eskimo Whaling Commission (AEWC) at their 4th Quarter Meeting on
December 13-14, 2012, in Anchorage.
Community POC meetings were held in Barrow, Kotzebue, Point Hope,
Point Lay, and Wainwright in January and February 2013. Finally, in
February 2013, TGS participated in the AEWC mini-convention and
Conflict Avoidance Agreement (CAA) discussion. A final POC that
documents all consultations with community leaders and subsistence
users was submitted to NMFS in May, 2013.
In addition, TGS signed a CAA with the Alaska whaling communities
to further ensure that its proposed open-water seismic survey
activities in the Chukchi Sea will not have unmitigable impacts to
subsistence activities. NMFS has included appropriate measures
identified in the CAA in the IHA.
Mitigation Conclusions
NMFS has carefully evaluated the mitigation measures and considered
a range of other measures in the context of ensuring that NMFS
prescribes the means of effecting the least practicable impact on the
affected marine mammal species and stocks and their habitat. Our
evaluation of potential measures included consideration of the
following factors in relation to one another:
The manner in which, and the degree to which, the
successful implementation of the measure is expected to minimize
adverse impacts to marine mammals; and
the practicability of the measure for applicant
implementation.
Based on our evaluation of the applicant's proposed measures, as
well as other measures considered by NMFS, NMFS has determined that the
required mitigation measures provide the means of effecting the least
practicable impact on marine mammal species or stocks and their
habitat, paying particular attention to rookeries, mating grounds, and
areas of similar significance.
Monitoring and Reporting Measures
In order to issue an ITA 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 ITAs
must include the suggested means of accomplishing the necessary
monitoring and reporting that will result in increased knowledge of the
species and of the level of taking or impacts on populations of marine
mammals that are expected to be present in the proposed action area.
I. Monitoring Measures
Monitoring will provide information on the numbers of marine
mammals potentially affected by the exploration operations and
facilitate real time mitigation to prevent injury of marine mammals by
industrial sounds or activities. These goals will be accomplished in
the Chukchi Sea during 2013 by conducting vessel-based monitoring from
both the source vessel and a supporting vessel and an acoustic
monitoring program using a towed hydrophone array to document marine
mammal presence and distribution in the vicinity of the survey area
beyond visual observation distances.
Visual monitoring by Protected Species Observers (PSOs) during
seismic operations, and periods when these surveys are not occurring,
will provide information on the numbers of marine mammals potentially
affected by these activities and facilitate real time mitigation to
prevent impacts to marine mammals by industrial sounds or operations.
Vessel-based PSOs onboard the survey vessel will record the numbers and
species of marine mammals observed in the area and any observable
reaction of marine mammals to the survey activities in the Chukchi Sea.
Real-time PAM would be conducted from the supporting vessel to
complement the visual monitoring conducted by PSOs during the seismic
surveys in the Chukchi Sea. Studies have indicated that towed PAM is a
practical and successful application for augmenting visual surveys of
low-frequency mysicetes, including blue and fin whales (Clark and
Fristrup 1997). Passive acoustics methods, including towed hydrophone
arrays, are most effective in remote areas, harsh environments (e.g.
the arctic) and when visibility and/or sea conditions are poor, or at
nighttime or during low-light conditions when animals cannot be sighted
easily. Surveys have collected more acoustic detections than visual
observations while using towed PAM in the Arctic during an open-water
seismic survey program conducted by Statoil in 2010 (McPherson et al.
2012). TGS states that the designed PAM system would provide the
possibility of advanced real-time notification of vocalizing marine
mammals that are not observed visually (or are observed after acoustic
detection) and allow for mitigation actions (i.e., power-down, shut-
down) to take place, if necessary.
Visual-Based Protected Species Observers (PSOs)
The visual-based marine mammal monitoring will be implemented by a team
of experienced PSOs, including both biologists and Inupiat personnel.
PSOs will be stationed aboard the survey and supporting vessels through
the duration of the project. The vessel-based marine mammal monitoring
will provide the basis for real-time mitigation measures as discussed
in the Mitigation Measures section. In addition, monitoring results of
the vessel-based monitoring program will include the estimation of the
number of ``takes'' as stipulated in the IHA.
(1) Protected Species Observers
Vessel-based monitoring for marine mammals will be done by trained
PSOs throughout the period of survey activities. The observers will
monitor the occurrence of marine mammals near the survey vessel during
all daylight periods during operation, and during most daylight periods
when operations are not occurring. PSO duties will include watching for
and identifying marine mammals; recording their numbers, distances, and
reactions to the survey operations; and documenting ``take by
harassment''.
A sufficient number of PSOs will be required onboard the survey
vessel to meet the following criteria:
100% Monitoring coverage during all periods of survey
operations in daylight;
maximum of 4 consecutive hours on watch per PSO; and
maximum of 12 hours of watch time per day per PSO.
PSO teams will consist of Inupiat observers and experienced field
biologists. Each vessel will have an experienced field crew leader to
supervise the PSO team. The total number of PSOs may decrease later in
the season as the duration of daylight decreases.
(2) Observer Qualifications and Training
Crew leaders and most PSOs will be individuals with experience as
observers during recent seismic, site clearance and shallow hazards,
and other monitoring projects in Alaska or other offshore areas in
recent years.
Biologist-observers will have previous marine mammal observation
experience, and field crew leaders will be highly experienced with
previous vessel-based marine mammal monitoring and mitigation projects.
Resumes for those individuals will be provided to NMFS
[[Page 51162]]
for review and acceptance of their qualifications. Inupiat observers
will be experienced in the region and familiar with the marine mammals
of the area. All observers will complete a NMFS-approved observer
training course designed to familiarize individuals with monitoring and
data collection procedures.
PSOs will complete a two or three-day training and refresher
session on marine mammal monitoring, to be conducted shortly before the
anticipated start of the 2013 open-water season. Any exceptions will
have or receive equivalent experience or training. The training
session(s) will be conducted by qualified marine mammalogists with
extensive crew-leader experience during previous vessel-based seismic
monitoring programs.
Marine Mammal Observer Protocol
Vessel-based visual monitoring for marine mammals shall be
conducted by NMFS-approved PSOs throughout the period of survey
activities, and extends to 30 minutes after the survey is completed.
The PSOs will watch for marine mammals from the best available vantage
point on the survey vessels, typically the bridge. The PSOs will scan
systematically with the unaided eye and 7 x 50 reticle binoculars,
supplemented with 20 x 60 image-stabilized Zeiss Binoculars or Fujinon
25 x 150 ``Big-eye'' binoculars, and night-vision equipment when
needed. Personnel on the bridge will assist the marine mammal
observer(s) in watching for marine mammals.
The observer(s) aboard the survey and support vessels will give
particular attention to the areas within the marine mammal exclusion
zones around the source vessel. These zones are the maximum distances
within which received levels may exceed 180 dB (rms) re 1 [micro]Pa
(rms) for cetaceans, or 190 dB (rms) re 1 [micro]Pa for pinnipeds.
Distances to nearby marine mammals will be estimated with
binoculars (Fujinon 7 x 50 binoculars) containing a reticle to measure
the vertical angle of the line of sight to the animal relative to the
horizon. Observers may use a laser rangefinder to test and improve
their abilities for visually estimating distances to objects in the
water.
When a marine mammal is seen approaching or within the exclusion
zone applicable to that species, the seismic survey crew will be
notified immediately so that mitigation measures called for in the
applicable authorization(s) can be implemented.
Night-vision equipment (Generation 3 binocular image intensifiers
or equivalent units) will be available for use when/if needed. In TGS'
Marine Mammal Monitoring and Mitigation Plan submitted in May 2013, TGS
stated that it would use the ITT F500 Series Generation 3 binocular
image intensifiers or equivalent units. However, TGS later notified
NMFS that such technology is restrict for export and thus cannot be
carried to high seas. Therefore, Generation 1 night-vision devices
(NVDs) will be used instead. Since the low-light hours during TGS'
survey period is very limited, and there is strict mitigation measures
prohibiting airgun ramp up from cold start when the entire exclusion
zones are not visible, NMFS considers that the unavailability of
Generation 3 NVDs does not compromise the effectiveness of mitigation
measures. Past experience with night-vision devices (NVDs) in the
Chukchi Sea and elsewhere has indicated that NVDs are not nearly as
effective as visual observation during daylight hours (e.g., Harris et
al. 1997, 1998; Moulton and Lawson 2002).
Field Data-Recording
The PSOs aboard the vessels will maintain a digital log of seismic
surveys, noting the date and time of all changes in seismic activity
(ramp-up, power-down, changes in the active seismic source, shutdowns,
etc.) and any corresponding changes in monitoring radii in a project-
customized Mysticetus\TM\ observation software spreadsheet. In
addition, PSOs will utilize this standardized format to record all
marine mammal observations and mitigation actions (seismic source
power-downs, shut-downs, and ramp-ups). Information collected during
marine mammal observations will include the following:
Vessel speed, position, and activity
Date, time, and location of each marine mammal sighting
Number of marine mammals observed, and group size, sex,
and age categories
Observer's name and contact information
Weather, visibility, and ice conditions at the time of
observation
Estimated distance of marine mammals at closest approach
Activity at the time of observation, including possible
attractants present
Animal behavior
Description of the encounter
Duration of encounter
Mitigation action taken
Data will preferentially be recorded directly into handheld
computers or as a back-up, transferred from hard-copy data sheets into
an electronic database. A system for quality control and verification
of data will be facilitated by the pre-season training, supervision by
the lead PSOs, in-season data checks, and will be built into the
Mysticetus\TM\ software (i.e., Mysticetus\TM\ will recognize and notify
the operator if entered data are non-sensical). Computerized data
validity checks will also be conducted, and the data will be managed in
such a way that it is easily summarized during and after the field
program and transferred into statistical, graphical, or other programs
for further processing. Mysticetus\TM\ will be used to quickly and
accurately summarize and display these data.
Passive Acoustic Monitoring
(1) Sound Source Measurements
Prior to or at the beginning of the seismic survey, sound levels
will be measured as a function of distance and direction from the
proposed seismic source array (full array and reduced to a single
mitigation airgun). Results of the acoustic characterization and SSV
will be used to empirically refine the modeled distance estimates of
the pre-season 190 dB, 180 dB, and 160 dB isopleths. The refined SSV
exclusion zones will be used for the remainder of the seismic survey.
Distance estimates for the 120 dB isopleth will also be modeled. The
results of the SSV will be submitted to NMFS within five days after
completing the measurements, followed by a report in 14 days. A more
detailed report will be provided to NMFS as part of the 90-day report
following completion of the acoustic program.
(2) Real-Time Passive Acoustic Monitoring
TGS will conduct real-time passive acoustic monitoring using a
towed hydrophone array from the support vessel. The towed hydrophone
array system consists of two parts: the ``wet end'' and the ``dry
end''. The wet end consists of the hydrophone array and tow cable that
is towed behind the vessel. The dry end includes the analog-to-digital,
computer processing, signal conditioning and filtering system used to
process, record and analyze the acoustic data. Specific noise filters
will be used to maximize the systems ability to detect low frequency
bowhead whales. The towed hydrophone array will be deployed using a
winch from the scout vessel. Details and specifications on the
equipment will be determined at a later date once TGS has selected an
acoustics contractor, as each contractor has different equipment
specifications.
Localization of vocalizing animals will be accomplished using
target motion analysis. With this method, it is possible with a single
towed
[[Page 51163]]
hydrophone array to obtain a localization to vocalizing animals given
certain assumptions. Due to the linear alignment of hydrophones, there
is a left/right ambiguity that cannot be resolved without turning the
tow vessel. The left/right ambiguity, however, is not a critical
concern for mitigation during the TGS 2D seismic survey because the
exclusion zones are circular; therefore, the distance to the calling
animal is the same on the right and left side of the vessel.
Furthermore, unambiguous localization can be achieved in circumstances
where the vessel towing the array can turn and the calling animals call
multiple times or continuously.
To ensure the effectiveness of real-time PAM with a towed
hydrophone array, the following requirements for PAM design and
procedures will be required:
Lowering Interferences From Flow Noise
Limit towing speeds to 4-6 knots. Reduce speed
appropriately if bowhead whales are detected so that bearing can be
obtained. If greater speeds are necessary, slow down every 20-30
minutes to listen for animal calls for at least 5-10 minutes.
Maintain straight track-lines unless right/left ambiguity
must be resolved (usually by turning 20-30 degrees at a time, then
maintaining a straight course until good bearings can be obtained).
Maintain a separation distance of at least several hundred
meters (preferably more) from the seismic survey vessel.
Design pre-amplifier filters that are `tuned' to reduce
low[hyphen]frequency flow and vessel noise.
If necessary, use a variable high-pass filter before
digitizing the signals.
Monitoring Marine Mammal Occurrence Within 160 dB Isopleths
Design a hydrophone array that is sensitive to frequencies
of interest (e.g. marine mammal sounds) but attenuates (via filters)
noise.
Use a processing system that can further signal conditions
(i.e. filter and match signal gains) to allow software to effectively
estimate bearings and/or localize.
Use software designed exclusively for monitoring,
localizing and plotting marine mammal calls.
Design the sampling software to optimize overlap between
monitoring the 180 and 160 dB isopleths.
Allow the survey vessel to deviate from designated
track[hyphen]lines by 25-30 degrees (for brief periods) so that left/
right ambiguity can be resolved.
Increase Localization Capability
Start with a simple hydrophone array, and if needed, add
additional capabilities (or hydrophones) to supplement this system. For
example, a 2[hyphen]hydrophone array that can do TMA but with an
additional array (or inline section) that can be added in front of the
primary array would allow crossed[hyphen]pair localization methods to
be used.
Use a processing and geographic display system that can
accommodate at least the TMA localization method, but also, additional
methods if needed.
Provide at least 300 m of cable (for TMA methods), and up
to 500 m if crossed[hyphen]pair or hyperbolic localization methods will
be used.
Monitoring Plan Peer Review
The MMPA requires that monitoring plans be independently peer
reviewed ``where the proposed activity may affect the availability of a
species or stock for taking for subsistence uses'' (16 U.S.C.
1371(a)(5)(D)(ii)(III)). Regarding this requirement, NMFS' implementing
regulations state, ``Upon receipt of a complete monitoring plan, and at
its discretion, [NMFS] will either submit the plan to members of a peer
review panel for review or within 60 days of receipt of the proposed
monitoring plan, schedule a workshop to review the plan'' (50 CFR
216.108(d)).
NMFS convened an independent peer review panel to review TGS'
mitigation and monitoring plan in its IHA application for taking marine
mammals incidental to the proposed open-water seismic survey in the
Chukchi Sea during 2013. The panel met on January 8 and 9, 2013, and
provided their final report to NMFS in March 2013. The full panel
report can be viewed at: http://www.nmfs.noaa.gov/pr/permits/incidental.htm#applications.
NMFS provided the panel with TGS' monitoring and mitigation plan
and asked the panel to address the following questions and issues for
TGS' plan:
Will the applicant's stated objectives effectively further
the understanding of the impacts of their activities on marine mammals
and otherwise accomplish the goals stated below? If not, how should the
objectives be modified to better accomplish the goals above?
Can the applicant achieve the stated objectives based on
the methods described in the plan?
Are there technical modifications to the proposed
monitoring techniques and methodologies proposed by the applicant that
should be considered to better accomplish their stated objectives?
Are there techniques not proposed by the applicant (i.e.,
additional monitoring techniques or methodologies) that should be
considered for inclusion in the applicant's monitoring program to
better accomplish their stated objectives?
What is the best way for an applicant to present their
data and results (formatting, metrics, graphics, etc.) in the required
reports that are to be submitted to NMFS (i.e., 90-day report and
comprehensive report)?
The peer review panel report contains recommendations that the
panel members felt were applicable to the TGS' monitoring plans. The
panel agrees that the objective of vessel-based monitoring to implement
mitigation measures to prevent or limit Level A takes is appropriate.
In addition, at the time the panel reviewed the TGS' proposed marine
mammal monitoring and mitigation plan, TGS only proposed vessel-based
visual monitoring (but subsequently added PAM as described above). The
panel was particularly concerned that there are considerable
limitations to the ability of PSOs to monitor the full extent of the
zones of influence, as these zones extend to as far as 15 km beyond the
source. In addition, the panel pointed out that TGS did not specify how
it planned to operate the scout vessel for marine mammal monitoring.
Specific recommendations provided by the peer review panel to
enhance marine mammal monitoring, especially far distance monitoring
beyond exclusion zones, include: (1) Implementing passive acoustic
monitoring, with bottom mounted passive acoustic recorders probably
being the most appropriate method; (2) deploying a real-time, passive
acoustic monitoring device that is linked by satellite (i.e., Iridium)
phone; (3) collaborating with NMFS to use aerial survey data for
assessing marine mammal distribution, relative abundance, behavior, and
possible impacts relative to seismic surveys; (4) looking into the
possibility of using unmanned aerial systems to survey for marine
mammals in offshore areas; and (5) utilizing new technologies, such as
underwater vehicles, gliders, satellite monitoring, etc., to conduct
far-field monitoring.
NMFS discussed extensively with TGS ways to improve far-field
marine mammal monitoring. As a result, upon further investigation and
conversations with both JASCO and Bio-Waves by TGS, as well as further
research into past Arctic marine mammal monitoring results conducted
with towed-PAM, NMFS and TGS agree that utilizing a
[[Page 51164]]
well-designed towed-PAM system would meet the need to provide enhanced
marine mammal monitoring beyond exclusion zones, as well as using
acoustic data for limited relative abundance and distribution analysis,
and possibly limited insights on impacts to marine mammals.
NMFS also studied other PAM methodologies suggested by the peer-
review panel. First, concerning deploying fixed bottom mounted
recorders, TGS states that it has been in contact with other operators
but was not able to find a collaborator to participate in long-term
acoustic monitoring due to the short-term nature of the proposed
survey. Regarding the real-time acoustic monitoring with fixed buoy,
TGS stated that it conducted an evaluation of this option and discussed
the possibility with the Cornell University's Bioacoustical Research
Program concerning its real-time marine acoustic recording unit (MARU),
but decided that the technology is still in the research and
development stage. TGS also states that it did not consider the
technology because the cost is more expensive than other PAM methods.
TGS also discussed (with NMFS scientists) the possibility of using
NMFS' aerial survey data for assessing marine mammal distribution,
relative abundance, and possible impacts relative to seismic surveys.
However, most of TGS' survey areas are outside NMFS aerial survey area,
which makes it impossible to use these datasets for impact analyses.
TGS also did a cost-benefit analysis of manned aerial surveys, and
eliminated this as an option due to increased health and safety
exposure risk, especially north of 72[deg]N. TGS also investigated the
possibility of using unmanned aerial vehicles (UAV) to survey for
marine mammals in offshore areas, however, it has also turned out not
to be feasible due to the fact that the approach is currently awaiting
an FAA permit to operate in the Arctic, and this permit could not be
guaranteed to be obtained in time for the TGS monitoring effort. TGS
states that it did consider new technologies, but did not feel that
they could justify the expense of testing techniques with unknown
capabilities in the Arctic environment.
In addition, the panel also recommends that TGS collaborate with
other organizations operating in the Chukchi Sea and share visual and
acoustic data to improve understanding of impacts from single and
multiple operations and efficacy of mitigation measures. Accordingly,
TGS plans to share these data via the OBIS-SEAMAP Web site entertaining
all appropriate data-sharing agreements, including data obtained using
towed PAM.
II. Reporting Measures
1. Sound Source Verification Reports
A report on the preliminary results of the sound source
verification measurements, including the measured 190, 180, and 160 dB
(rms) radii of the airgun sources, would be submitted within 14 days
after collection of those measurements at the start of the field
season. This report will specify the distances of the exclusion zones
that were adopted for the survey.
2. Field Reports
Throughout the survey program, PSOs will prepare a report each day
or at such other intervals, summarizing the recent results of the
monitoring program. The reports will summarize the species and numbers
of marine mammals sighted. These reports will be provided to NMFS and
to the survey operators.
3. Technical Reports
The results of TGS' 2013 vessel-based monitoring, including
estimates of ``take'' by harassment, would be presented in the ``90-
day'' and Final Technical reports, if the IHA is issued for the
proposed open-water 2D seismic surveys. The Technical Reports should be
submitted to NMFS within 90 days after the end of the seismic survey.
The Technical Reports will include:
(a) Summaries of monitoring effort (e.g., total hours, total
distances, and marine mammal distribution through the study period,
accounting for sea state and other factors affecting visibility and
detectability of marine mammals);
(b) Analyses of the effects of various factors influencing
detectability of marine mammals (e.g., sea state, number of observers,
and fog/glare);
(c) Species composition, occurrence, and distribution of marine
mammal sightings, including date, water depth, numbers, age/size/gender
categories (if determinable), group sizes, and ice cover;
(d) To better assess impacts to marine mammals, data analysis
should be separated into periods when a seismic airgun array (or a
single mitigation airgun) is operating and when it is not. Final and
comprehensive reports to NMFS should summarize and plot:
Data for periods when a seismic array is active and when
it is not; and
The respective predicted received sound conditions over
fairly large areas (tens of km) around operations;
(e) Sighting rates of marine mammals during periods with and
without airgun activities (and other variables that could affect
detectability), such as:
initial sighting distances versus airgun activity state;
closest point of approach versus airgun activity state;
observed behaviors and types of movements versus airgun
activity state;
numbers of sightings/individuals seen versus airgun
activity state;
distribution around the survey vessel versus airgun
activity state; and
estimates of take by harassment;
(f) Reported results from all hypothesis tests should include
estimates of the associated statistical power when practicable;
(g) Estimate and report uncertainty in all take estimates.
Uncertainty could be expressed by the presentation of confidence
limits, a minimum-maximum, posterior probability distribution, etc.;
the exact approach would be selected based on the sampling method and
data available;
(h) The report should clearly compare authorized takes to the level
of actual estimated takes; and
(i) Methodology used to estimate marine mammal takes and relative
abundance on towed PAM.
4. Notification of Injured or Dead Marine Mammals
In addition, NMFS would require TGS to notify NMFS' Office of
Protected Resources and NMFS' Stranding Network within 48 hours of
sighting an injured or dead marine mammal in the vicinity of seismic
survey operations. TGS shall provide NMFS with the species or
description of the animal(s), the condition of the animal(s) (including
carcass condition if the animal is dead), location, time of first
discovery, observed behaviors (if alive), and photo or video (if
available).
In the event that an injured or dead marine mammal is found by TGS
that is not in the vicinity of the proposed open-water seismic survey
program, TGS would report the same information as listed above as soon
as operationally feasible to NMFS.
Estimated Take by Incidental Harassment
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,
[[Page 51165]]
feeding, or sheltering [Level B harassment]. Only take by Level B
behavioral harassment is anticipated as a result of the proposed open-
water seismic survey program. Anticipated impacts to marine mammals are
associated with noise propagation from the survey airgun(s) used in the
seismic surveys.
The full suite of potential impacts to marine mammals was described
in detail in the ``Potential Effects of the Specified Activity on
Marine Mammals'' section found earlier in this document. The potential
effects of sound from the proposed open-water seismic survey programs
might include one or more of the following: masking of natural sounds;
behavioral disturbance; non-auditory physical effects; and, at least in
theory, temporary or permanent hearing impairment (Richardson et al.
1995). As discussed earlier in this document, the most common impact
will likely be from behavioral disturbance, including avoidance of the
ensonified area or changes in speed, direction, and/or diving profile
of the animal. For reasons discussed previously in this document,
hearing impairment (TTS and PTS) is highly unlikely to occur based on
the mitigation and monitoring measures that would preclude marine
mammals from being exposed to noise levels high enough to cause hearing
impairment.
For impulse sounds, such as those produced by airgun(s) used in the
2D seismic surveys, NMFS uses the 160 dB (rms) re 1 [mu]Pa isopleth to
indicate the onset of Level B harassment. TGS provided calculations for
the 160-dB isopleths produced by the proposed seismic surveys and then
used those isopleths to estimate takes by harassment. NMFS used the
calculations to make the necessary MMPA findings. TGS provided a full
description of the methodology used to estimate takes by harassment in
its IHA application, which is also provided in the following sections.
Basis for Estimating ``Take by Harassment''
The estimated takes by harassment is calculated in this section by
multiplying the expected densities of marine mammals that may occur
near the planned activities by the area of water likely to be exposed
to impulse sound levels of >=160 dB (rms) re 1 [mu]Pa.
Marine mammal occurrence near the operation is likely to vary by
season and habitat, mostly related to the presence or absence of sea
ice. Although current NMFS' noise exposure standards state that Level B
harassment occurs at exposure levels >=160 dB (rms) re 1 [mu]Pa by
impulse sources, there is no evidence that avoidance at these received
sound levels would have significant biological effects on individual
animals. Any changes in behavior caused by sounds at or near the
specified received levels would likely fall within the normal variation
in such activities that would occur in the absence of the planned
operations. However, these received levels are currently used to set
the threshold for Level B behavioral harassment.
Marine Mammal Density Estimates
The first step in estimating the number of marine mammals that
might be ``taken by harassment'' was to conduct a review of available
data on density estimates for the marine mammal species occurring in
the project vicinity and adjacent areas of the Chukchi Sea. While
several densities are available for U.S. waters in the Chukchi Sea, no
reliable estimates are known for U.S. waters north of 72[deg] N.
Furthermore, no systematic surveys are known for the western half of
the proposed project area in international waters.
Therefore, densities used to estimate exposures were based on two
recent IHA applications and three 90-day reports to NMFS summarizing
results of field monitoring surveys. These project areas overlapped the
proposed TGS project area to at least some extent as well as TGS'
proposed seismic operations period. A map showing the boundaries of
these survey areas relative to TGS' proposed seismic line locations is
provided in Figure 2 of TGS' IHA application. The surveys consisted of
the (1) Two Statoil 90-day reports from the northern Chukchi Sea (Blees
et al. 2010; Hartin et al. 2011), (2) UAGI's IHA (LGL 2011) and 90-day
report (Cameron et al. 2012), and (3) Shell 2012 IHA (Shell 2011).
These data are considered the ``best available'' density estimates and
occurrence data currently available for the project area.
All recent density estimates for four different project areas
overlapping the TGS project area based on the observed or derived
densities reported in other studies (Blees et al. 2010; Hartin et al.
2011; LGL 2011; Shell 2011; Cameron et al. 2012) and are shown in Table
3 of TGS' IHA application. Note that only the Cameron et al. (2012)
survey occurred north of 72[deg] N in U.S. waters and international
waters partially overlapping the TGS project area. Sightings providing
data on observed densities were available for the following six
species: the bowhead, gray and beluga whale, and the bearded, ringed
and spotted seal. The remaining other six species occur so rarely in
the project area vicinity that reliable densities are not available for
them and/or no sightings were made during the reported surveys: the
humpback, minke, fin, and killer whales, the harbor porpoise, and the
ribbon seal (Blees et al. 2010; Hartin et al. 2011; Cameron et al.
2012). Thus, certain fractional numbers were assigned to them based on
those reported for other IHAs overlapping the proposed TGS project
area, to address the rare chance of an encounter (Blees et al. 2010;
Hartin et al. 2011; LGL 2011; Shell 2011; Cameron et al. 2012).
Adjustment Factors Applied to Provide Lower and Upper Estimates of
Density
A number of habitat parameters have been shown to influence the
distribution of marine mammal species occurring in the TGS project
area. These parameters were applied to adjust the density of species
accordingly, as done by other applicants in previous IHA applications
(e.g., Blees et al. 2010; Hartin et al. 2011; LGL 2011; Shell 2011,
Cameron et al. 2012). These included (1) open water (i.e., ice-free)
vs. ice-edge margin (higher densities of pinnipeds and beluga whales
occur near and/or within the ice margin), (2) summer (July-August) vs.
fall (September-October), (3) water depth (>200 vs. <200 m deep), and
(4) likelihood of occurrence above or below 72[deg] N. Open-water
densities were used if available because TGS operations must completely
avoid ice to be able to safely and effectively conduct operations.
Densities (Table 3 in TGS' IHA application) used to estimate and
calculate the number of exposures to TGS' seismic impulse sound levels
>=160 dB (rms) re1[mu]Pa were obtained by (1) averaging the densities
from the four previous studies by summer (July-August), fall
(September-October), and summer-fall, and then (2) multiplying the
resulting averaged densities by adjustment factors for water depth
(shallower or deeper than 200 m) and expected occurrence in waters
north or south of 72[deg] N. Notably, TGS plans to operate above
72[deg] N for about half (32 days) of the total 45-60-day period in US
Federal waters (35 days of which would involve seismic operations), and
for all operations in international waters, up to 33 days. These
northern waters above 72[deg] N would be accessed sometime between
about mid-September and 15 October (when waters are ice-free).
Because few data were available for most of the survey area,
particularly north of 72[deg] N and west of Barrow, it is not known how
closely the applied average densities reflect the actual densities that
will be encountered
[[Page 51166]]
during the proposed TGS seismic survey. Thus, lower and upper
adjustment factors (Table 4 in TGS' IHA application) were multiplied by
the averaged densities to provide a range of density estimates. The
latter adjustment was incorporated into a formula to estimate exposures
to seismic sounds. The ``lower adjustment factor'' does not apply
adjustment factors to densities north of 72[deg] N for the bowhead and
beluga whale and the ringed and bearded seal. In contrast, the ``upper
adjustment factor'' applies factors to account for the expected lower
density of marine mammal species north of 72[deg] N. Adjustment factors
differed by species and were based on (1) the reported distribution and
occurrence of each species in these waters, and (2) factors applied by
ION (LGL 2012) for their 2012 IHA application for the fall period of
Oct-Dec 2012 that overlapped the fall period (mid-to-late September-
October) and north-easternmost region that TGS expects to operate in
international waters during fall.
TGS applied these density data and factors previously applied in an
IHA issued to ION to account for expected lower densities above 72[deg]
N where waters are predominantly >1,000 m deep. The upper-adjusted
(i.e., lower) density estimate was calculated by multiplying reported
fall densities for more southern Chukchi waters as follows: (1) by a
factor of 0.0 for fin, humpback, minke and killer whales, and harbor
porpoise and ribbon and spotted seals as they are not expected in
waters above 72[deg] N and thus were assumed not to occur there; (2) by
an adjustment factor of 0.01 for gray whales (since the northernmost
boundary of their distribution is near 72[deg] N and they are thus
considered highly unlikely to occur above 72[deg] N; (3) by a factor of
0.1 for bowhead whales as the area is outside the main migration
corridor, and (4) by a factor of 0.1 for beluga whales and bearded and
ringed seals as they are closely associated with ice, and thus
considered less likely to occur in ice-free waters needed to conduct
the TGS seismic operations.
A similar 0.1 adjustment factor was applied in the ION IHA (LGL
2012) for species where the seismic survey area was on the edge of that
species' range at the given time of year. ION's adjustment factor of
0.1 was used for TGS density estimates because TGS proposes to be well
north and west of ION's westernmost 2012 survey lines no earlier than
15-30 September through 31 October 2013. In comparison, ION proposed
their program for 1 October through mid-December, and their actual
program occurred in the Chukchi and Beaufort Seas from 20 October-9
November, 2012. These periods overlap the majority of the period that
TGS is expected to be operating at or near the westernmost seismic
lines (no earlier than 15-30 September through October) between
73[deg]-76[deg] N and 160[deg] W to 160[deg] E. Thus, ION's ``late
season'' period coincides with TGS' proposed late fall season both in
time and space relative to waters above 72[deg] N.
The upper density estimates consisted of the averaged fall
densities for more southern Chukchi waters by only (1) a smaller
adjustment factor of 0.20 for gray whales (Table 4 of TGS' IHA
application), and (2) by the same factor of 0.0 for fin, humpback,
minke and killer whales, and harbor porpoise and ribbon and spotted
seals as described above.
Additional Rationale for Adjusting Densities North of 72[deg] N
No whale sightings have been reported in waters north of
72[deg] N during the few recent vessel-based surveys conducted there
that overlapped the southern or eastern part of the proposed TGS
project area and season (Blees et al. 2010; Hartin et al. 2011; Cameron
et al. 2012).
The main fall migration corridor for bowheads reportedly
occurs south of 72[deg] N (Quakenbush et al. 2010). However, satellite-
tagging studies indicate that at least some individual bowheads migrate
generally west/southwest across the project area in waters above
72[deg] N and west of Barrow during the fall migration from September-
November (Quakenbush 2007; LGL 2011; Quakenbush et al. 2012).
The reported gray whale distribution in the Chukchi Sea
normally does not extend much north of 72[deg] N during summer/fall
(Jefferson et al. 2008). This northernmost peripheral boundary area is
thus expected to have very low gray whale densities. Furthermore, most
gray whales will have migrated south of the project area by fall (Rice
and Wolman 1971; Allen and Angliss 2012).
Exposure Calculation Methods
The approach used to calculate the estimated number of individuals
of each marine mammal species potentially exposed to received levels of
seismic impulse sound levels >=160 dB (rms) re 1 [mu]Pa during the
proposed seismic project is described below.
1. The area of water (in km\2\) ensonified to >=160 dB (rms) re 1
[mu]Pa around the operating seismic source array on seismic lines as
well as turns and transits between seismic lines was calculated for
U.S. and international waters for waters shallower and deeper than 200
m, and for waters north and south of 72[deg] N (Table 2). It was
assumed for purposes of this estimation that the full seismic source
array would be used during all seismic lines and during the 1-km run-in
and 5-km run-out between seismic lines. In addition, it was assumed
that a single 60 in\3\ airgun would be used during turns and transits
between seismic lines. Ensonified waters were calculated as follows.
2. A buffer was applied on both sides of the planned survey
tracklines equivalent to the distances modeled for the proposed 3,280
in\3\ seismic source array by JASCO in 2010 at three locations in the
project area (Zykov et al. 2013). The buffer width corresponding to
this 160 (rms) dB re 1 [mu]Pa isopleth varied with three water depth
categories. Thus, survey tracklines located over waters 17-40 m deep
were buffered by 8.5 km, those over waters 41-100 m deep were buffered
by 9.9 km, and those over water depths of >100 m were buffered by 15
km.
[[Page 51167]]
Table 2--Estimated Area (km\2\) Ensonified to >160 dB (rms) re 1 [mu]Pa by Seismic Impulses Along TGS' 2013 Proposed Seismic Lines and Turns in U.S. and
International Waters of the Chukchi Sea. Ensonified Areas Assumed That the Full 3,280 in\3\ Array Operated Continuously on Survey Lines and That the
Single Mitigation Airgun (60 in\3\) Operated Continuously on Turns (and Transits) Between Survey Lines
--------------------------------------------------------------------------------------------------------------------------------------------------------
Above 72[deg]N Below 72[deg]N Water depth < 200m Water depth > 200m All lines All turns All lines &
-------------------------------------------------------------------------------------------------------------- turns
------------
Total Turns Total Turns Total Turns Total Turns Total Total Total
lines area lines area lines area lines area lines turns ensonified
area area area area area area area
(km\2\) (km\2\) (km\2\) (km\2\) (km\2\) (km\2\) (km\2\) (km\2\) (km\2\) (km\2\) (km\2\)
--------------------------------------------------------------------------------------------------------------------------------------------------------
US........................... 65477 1294 72974 1442 114858 2770 23594 466 138452 2736 141188
International................ 115135 4200 0 0 45954 1676 69181 2524 115135 4200 119335
--------------------------------------------------------------------------------------------------------------------------
Total.................... 180612 5494 72974 1442 160812 3946 92775 2990 253586 6936 260522
--------------------------------------------------------------------------------------------------------------------------------------------------------
3. A smaller buffer was applied to both sides of turn lines between
seismic lines equivalent to the measured distance to the 160 dB (rms)
re 1 [mu]Pa isopleth of a single 60 in\3\ array as measured by JASCO.
The associated area in km\2\ was calculated using
MysticetusTM software. MysticetusTM identified
water depths at 100-m intervals along the survey trackline using
bathymetric data. At each 100-m interval, MysticetusTM
applied one of the three aforementioned 160 dB (rms) re 1 [mu]Pa radius
isopleths corresponding to that water depth. Overlapping areas were
treated separately. The resulting World Geodetic System (WGS) 84
polygons were re-projected into North Pole Stereographic coordinates
and the total area was calculated.
4. Averaged densities of marine mammals (Table 3 in TGS' IHA
application) were adjusted as applicable (Table 4 in TGS' IHA
application) then multiplied by the area predicted to be ensonified to
>=160 dB (rms) re 1 [mu]Pa. The procedure is outlined below.
Because TGS expects to conduct seismic lines in U.S.
Federal waters sometime between mid-July and mid-September in late
summer and early fall, the proportion of U.S. Federal waters ensonified
to >160 dB (rms) re 1 [mu]Pa was multiplied by the average of summer
and fall densities reported from other studies (Table 3 in TGS' IHA
application).
Because TGS expects to conduct seismic lines in
international waters starting in fall from mid-to-late September
through October, the proportion of international waters ensonified to
>160 dB (rms) re 1 [mu]Pa was multiplied by the average of fall
densities reported from other studies (based nearly exclusively on
surveys south of 72[deg] N since it is considered the best and only
systematic data available for the region).
The proportions of ensonified waters north and south of
72[deg] N were also calculated for U.S. and international waters.
Species-specific average summer-fall and fall densities associated with
these depth categories were multiplied by the corresponding proportion
and season.
In addition, the proportions of ensonified waters where
water depth along the seismic line was <200 m deep or >200 m deep were
calculated. Species-specific average summer-fall and fall densities
associated with these depth categories were multiplied by the
corresponding proportion and season.
Reported fall density estimates for gray, bowhead and
beluga whales, and bearded and ringed seals were adjusted for ice-free
waters N of 72[deg] N by multiplying reported fall densities for more
southern Chukchi waters by low and high adjustment factors described
above to provide a range of potential exposures.
In a summary, estimated species exposures are calculated by
multiplying seasonally (summer vs. fall) and spatially (above vs. below
72[deg] N at various water depths) marine mammal density by the total
ensonified areas with received levels higher than 160 dB re 1[mu]Pa
(rms).
Potential Number of ``Take by Harassment''
As stated earlier, the estimates of potential Level B takes of
marine mammals by noise exposure are based on a consideration of the
number of marine mammals that might be present during operations in the
Chukchi Sea and the anticipated area exposed to those sound pressure
levels (SPLs) above 160 dB re 1 [micro]Pa for impulse sources (seismic
airgun during 2D seismic surveys).
Some of the animals estimated to be exposed, particularly migrating
bowhead whales, might show avoidance reactions before being exposed to
sounds at the specified threshold levels. Thus, these calculations
actually estimate the number of individuals potentially exposed to the
specified sounds levels that would occur if there were no avoidance of
the area ensonified to that level.
Numbers of marine mammals that might be present and potentially
taken are summarized in Table 3 based on calculation described above.
Table 3--Estimates of the Possible Maximum Numbers of Marine Mammals
Taken by Level B Harassment (Exposed to >=160 dB From Airgun Sound)
During TGS' Proposed 2D Seismic Survey in the Chukchi Sea, July-October
2013
------------------------------------------------------------------------
Level B Percent
Species takes population
------------------------------------------------------------------------
Bowhead whale................................. 794 4.70
Gray whale.................................... 1,363 7.13
Fin whale..................................... 5 0.09
Humpback whale................................ 5 0.53
Minke whale................................... 5 0.62
Beluga whale.................................. 412 11.11
Killer whale.................................. 5 1.59
Harbor porpoise............................... 36 0.07
Ringed seal................................... 30,000 14.36
Bearded seal.................................. 6000 0.84
Spotted seal.................................. 500 0.84
Ribbon seal................................... 100 0.20
------------------------------------------------------------------------
Estimated Take Conclusions
Effects on marine mammals are generally expected to be restricted
to avoidance of the area around the planned activities and short-term
changes in behavior, falling within the MMPA definition of ``Level B
harassment''.
Cetaceans--The take calculation estimates suggest a total of 794
bowhead whales may be exposed to sounds at or above 160 dB (rms) re 1
[micro]Pa (Table 3). This number is approximately 7.53% of the Bering-
Chukchi-Beaufort (BCB) population of 16,892 assessed in 2011 (Givens et
al. 2013). The total estimated number of gray and beluga whales that
[[Page 51168]]
may be exposed to sounds from the activities ranges up to 1,363 and
412, respectively (Table 3). Fewer harbor porpoises are likely to be
exposed to sounds during the activities. The small numbers of other
whale species that may occur in the Chukchi Sea are unlikely to be
present around the planned operations but chance encounters may occur.
The few individuals would represent a very small proportion of their
respective populations.
Pinnipeds--Ringed seal is by far the most abundant species expected
to be encountered during the planned operations. The best estimate of
the numbers of ringed seals exposed to sounds at the specified received
levels during the planned activities is 30,000, which represent up to
14.36% of the Alaska population. Fewer individuals of other pinniped
species are estimated to be exposed to sounds at Level B behavioral
harassment level, also representing small proportions of their
populations.
Negligible Impact and Small Numbers Analysis and Determination
As a preliminary matter, we typically include our negligible impact
and small numbers analysis and determination under the same section
heading of our Federal Register Notices. Despite co-locating these
terms, we acknowledge that negligible impact and small numbers are
distinct standards under the MMPA and treat them as such. The analysis
presented below does not conflate the two standards; instead, each has
been considered independently and we have applied the relevant factors
to inform our negligible impact and small numbers determinations.
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.'' In making a negligible impact determination,
NMFS considers a variety of factors, including but not limited to: (1)
The number of anticipated mortalities; (2) the number and nature of
anticipated injuries; (3) the number, nature, intensity, and duration
of Level B harassment; and (4) the context in which the takes occur.
No injuries or mortalities are anticipated to occur as a result of
TGS' proposed 2013 open-water 2D seismic surveys in the Chukchi Sea,
and none are being authorized. Additionally, animals in the area are
not expected to incur hearing impairment (i.e., TTS or PTS) or non-
auditory physiological effects. Takes will be limited to Level B
behavioral harassment. Although it is possible that some individuals of
marine mammals may be exposed to sounds from seismic survey activities
more than once, the expanse of these multi-exposures are expected to be
less extensive since both the animals and the survey vessels will be
moving constantly in and out of the survey areas.
Most of the bowhead whales encountered will likely show overt
disturbance (avoidance) only if they receive airgun sounds with levels
>= 160 dB re 1 [mu]Pa. Odontocete reactions to seismic airgun pulses
are usually assumed to be limited to shorter distances from the
airgun(s) than are those of mysticetes, probably in part because
odontocete low-frequency hearing is assumed to be less sensitive than
that of mysticetes. However, at least when in the Canadian Beaufort Sea
in summer, belugas appear to be fairly responsive to seismic energy,
with few being sighted within 6-12 mi (10-20 km) of seismic vessels
during aerial surveys (Miller et al. 2005). Belugas will likely occur
in small numbers in the Chukchi Sea during the survey period and few
will likely be affected by the survey activity.
As noted, elevated background noise level from the seismic airgun
reverberant field could cause acoustic masking to marine mammals and
reduce their communication space. However, even though the decay of the
signal is extended, the fact that pulses are separated by approximately
10 seconds means that overall received levels at distance are expected
to be much lower, thus resulting in less acoustic masking.
Taking into account the mitigation measures that are planned,
effects on marine mammals are generally expected to be restricted to
avoidance of a limited area around TGS' open-water activities and
short-term changes in behavior, falling within the MMPA definition of
``Level B harassment''. The many reported cases of apparent tolerance
by cetaceans of seismic exploration, vessel traffic, and some other
human activities show that co-existence is possible. Mitigation
measures such as controlled vessel speed, dedicated marine mammal
observers, non-pursuit, and shut downs or power downs when marine
mammals are seen within defined ranges will further reduce short-term
reactions and minimize any effects on hearing sensitivity. In all
cases, the effects are expected to be short-term, with no lasting
biological consequence.
Of the thirteen marine mammal species likely to occur in the
seismic survey area, bowhead, fin, and humpback whales and ringed and
bearded seals are listed as endangered or threatened under the ESA.
These species are also designated as ``depleted'' under the MMPA.
Despite these designations, the BCB stock of bowheads has been
increasing at a rate of 3.4 percent annually for nearly a decade (Allen
and Angliss 2010). Additionally, during the 2001 census, 121 calves
were counted, which was the highest yet recorded. The calf count
provides corroborating evidence for a healthy and increasing population
(Allen and Angliss 2010). The occurrence of fin and humpback whales in
the seismic survey areas is considered very rare. There is no critical
habitat designated in the U.S. Arctic for the bowhead, fin, and
humpback whales. The Alaska stock of bearded seals, part of the
Beringia distinct population segment (DPS), and the Arctic stock of
ringed seals, have recently been listed by NMFS as threatened under the
ESA. None of the other species that may occur in the project area are
listed as threatened or endangered under the ESA or designated as
depleted under the MMPA.
Potential impacts to marine mammal habitat were discussed
previously in this document (see the ``Anticipated Effects on Habitat''
section). Although some disturbance is possible to food sources of
marine mammals, the impacts are anticipated to be minor enough as to
not affect rates of recruitment or survival of marine mammals in the
area. Based on the vast size of the Arctic Ocean where feeding by
marine mammals occurs versus the localized area of the seismic survey
activities, any missed feeding opportunities in the direct project area
would be minor based on the fact that other feeding areas exist
elsewhere.
The authorized take represents 11.11% of the Eastern Chukchi Sea
population of approximately 3,710 beluga whales, 1.59% of Aleutian
Island and Bering Sea stock of approximately 314 killer whales, 0.07%
of Bering Sea stock of approximately 48,215 harbor porpoises, 7.13% of
the Eastern North Pacific stock of approximately 19,126 gray whales,
7.53% of the Bering-Chukchi-Beaufort population of 10,545 bowhead
whales, 0.53% of the Western North Pacific stock of approximately 938
humpback whales, 0.09% of the Northeast Pacific stock of approximately
5,700 fin whales, and 0.62% of the Alaska stock of approximately 810
minke whales. The take estimates presented for ringed, bearded,
spotted, and ribbon seals represent 14.36, 2.47, 0.84, and 0.20% of
U.S. Arctic stocks of
[[Page 51169]]
each species, respectively. The mitigation and monitoring measures
(described previously in this document) included in the IHA are
expected to reduce even further any potential disturbance to marine
mammals.
In addition, no important feeding and reproductive areas are known
in the vicinity of the TGS' seismic surveys at the time the surveys are
to take place. No critical habitat of ESA-listed marine mammal species
occurs in the Chukchi Sea.
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 mitigation and monitoring
measures, NMFS finds that TGS' 2013 open-water 2D seismic surveys in
the Chukchi Sea may result in the incidental take of small numbers of
marine mammals, by Level B harassment only, and that the total taking
from the seismic surveys will have a negligible impact on the affected
species or stocks.
Unmitigable Adverse Impact Analysis and Determination
NMFS has determined that TGS' 2013 open-water 2D seismic surveys in
the Chukchi Sea will not have an unmitigable adverse impact on the
availability of species or stocks for taking for subsistence uses. This
determination is supported by information contained in this document
and TGS' POC. TGS has adopted a spatial and temporal strategy for its
Chukchi Sea open-water seismic surveys that will help ensure its survey
will have no unmitigable impacts to subsistence hunters. Due to the
timing of the project and the distance from the surrounding
communities, it is anticipated to have no effects on spring harvesting
and little or no effects on the occasional summer harvest of beluga
whale, subsistence seal hunts (ringed and spotted seals are primarily
harvested in winter while bearded seals are hunted during July-
September in the Beaufort Sea), or the fall bowhead hunt.
In addition, based on the measures described in TGS' POC, the
required mitigation and monitoring measures (described earlier in this
document), and the project design itself, NMFS has determined that
there will not be an unmitigable adverse impact on subsistence uses
from TGS' 2013 open-water 2D seismic surveys in the Chukchi Sea.
Endangered Species Act (ESA)
The bowhead, fin, and humpback whales and ringed and bearded seals
are the only marine mammal species currently listed as endangered or
threatened under the ESA that could occur during TGS' 2D seismic
surveys during the Arctic open-water season. NMFS' Permits and
Conservation Division consulted with NMFS' Alaska Regional Office
Division of Protected Resources under section 7 of the ESA on the
issuance of an IHA to TGS under section 101(a)(5)(D) of the MMPA for
this activity. A Biological Opinion was issued on July 10, 2013, which
concludes that issuance of the IHA is not likely to jeopardize the
continued existence of the ESA-listed marine mammal species. NMFS will
issue an Incidental Take Statement under this Biological Opinion which
contains reasonable and prudent measures with implementing terms and
conditions to minimize the effects of take of listed species.
National Environmental Policy Act (NEPA)
NMFS prepared an EA that includes an analysis of potential
environmental effects associated with NMFS' issuance of an IHA to TGS
to take marine mammals incidental to conducting its 2D seismic surveys
in the Chukchi Sea during the 2013 open-water season. NMFS has
finalized the EA and prepared a FONSI for this action. Therefore,
preparation of an EIS is not necessary.
Authorization
As a result of these determinations, NMFS has issued an IHA to TGS
to take marine mammals incidental to its 2013 seismic survey in the
Chukchi Sea, Alaska, provided the previously mentioned mitigation,
monitoring, and reporting requirements are incorporated.
Dated: August 14, 2013.
Donna S. Wieting,
Director, Office of Protected Resources, National Marine Fisheries
Service.
[FR Doc. 2013-20310 Filed 8-19-13; 8:45 am]
BILLING CODE 3510-22-P