[Federal Register Volume 77, Number 206 (Wednesday, October 24, 2012)]
[Notices]
[Pages 65060-65090]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2012-26103]
[[Page 65059]]
Vol. 77
Wednesday,
No. 206
October 24, 2012
Part II
Department of Commerce
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National Oceanic and Atmospheric Administration
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Takes of Marine Mammals Incidental to Specified Activities; Taking
Marine Mammals Incidental to Marine Seismic Survey in the Beaufort and
Chukchi Seas, Alaska; Notice
Federal Register / Vol. 77 , No. 206 / Wednesday, October 24, 2012 /
Notices
[[Page 65060]]
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DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
RIN 0648-XC091
Takes of Marine Mammals Incidental to Specified Activities;
Taking Marine Mammals Incidental to Marine Seismic Survey in the
Beaufort and Chukchi Seas, 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 ION Geophysical (ION) to
take, by harassment, small numbers of nine species of marine mammals
incidental to in-ice marine seismic surveys in the Beaufort and Chukchi
Seas, Alaska, during the fall and winter of 2012.
DATES: Effective October 17, 2011, through December 15, 2012.
ADDRESSES: Requests 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 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 (Secretary) to allow, upon request,
the incidental, but not intentional taking 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 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 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 taking 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. 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].
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 issuance of the authorization.
Summary of Request
NMFS received an application on March 1, 2012, from ION for the
taking, by harassment, of marine mammals incidental to a marine seismic
survey in ice in the Beaufort and Chukchi Seas, Alaska, during October
through December 15, 2012. After addressing comments from NMFS, ION
modified its application and submitted a revised application on June
11, 2012.
Description of the Specified Activity
ION's activities consist of a geophysical in-ice (seismic
reflection/refraction) survey and related vessel operations to be
conducted primarily in the Alaskan Beaufort and Chukchi seas from
October to December 15, 2012. The primary survey area extends from the
U.S.-Canadian border in the east to Point Barrow in the west. Two
survey lines extend west of Point Barrow into the northern Chukchi Sea,
and three short tracks are proposed near the U.S.-Russian border (see
Figure 1 of ION's IHA application). The bathymetry of the proposed
survey area ranges from shallow (<20 m [66 ft]) to relatively deep
(>3,500 m [11,483 ft]) water over the continental shelf, the
continental slope, and the abyssal plain.
The survey will be conducted from the seismic vessel Geo Arctic
escorted by the Polar Prince, a medium class (100A) icebreaker. The
survey grid consists of ~7,175 km (4,458 mi) of transect line, not
including transits when the airguns are not operating. There may be
small amounts of additional seismic operations associated with airgun
testing, start up, and repeat coverage of any areas where initial data
quality is sub-standard. The seismic source towed by the Geo Arctic
would be an airgun array consisting of 26 active Sercel G-gun airguns
with a total volume of 4,450 in\3\. A single hydrophone streamer 4.5-9
km (2.8-5.6 mi) in length, depending on ice conditions, would be towed
by the Geo Arctic to record the returning seismic signals.
The survey vessels arrived in the survey area from Canadian waters
in early October and plan to begin data collection on or after October
15, 2012. After completion of the survey, or when ice and weather
conditions dictate, the vessels will exit to the south, transiting
through the Chukchi and Bering Seas. The Polar Prince may be used to
perform an at-sea refueling (bunkering) operation to supply as much as
500 metric tons of Arctic diesel to the Geo Arctic. The Polar Prince
will carry that fuel onboard at the start of the operation, and it will
be transferred to the Geo Arctic if/when necessary. Depending on its
own fuel consumption, the Polar Prince may then transit to Tuktoyuktuk,
Canada to take on additional fuel for itself. Once the Polar Prince
returns to the Geo Arctic the survey would continue. The entire
refueling operation will therefore involve one fuel transfer and
potentially one transit to and from Tuktoyuktuk. The refueling
operation will likely take place in late October, at which time the
[[Page 65061]]
Geo Arctic will likely be in the eastern or east-central Alaskan
Beaufort Sea.
ION's geophysical survey has been designed and scheduled to
minimize potential effects to marine mammals, bowhead whales in
particular, and subsistence users. For mitigation and operational
reasons, the survey area has been bisected by a line that runs from
70.5[deg] N. 150.5[deg] W. to 73[deg] N. 148[deg] W. (see Figure 1 of
ION's IHA application). Weather and ice permitting, ION plans to begin
survey operations east of the line described above (eastern survey
area) and in offshore waters (>1,000 m [3,281 ft]) where bowheads are
expected to be least abundant in early October. This operational plan
is based on the fact that only ~2% of bowhead whales observed by Bureau
of Ocean Energy Management's (BOEM) aerial surveys from 1979-2007
occurred in areas of water depth >1,000 m (3,281 ft) (MMS, 2010), and
on average ~97% of bowheads have passed through the eastern U.S.
Beaufort Sea by October 15 (Miller et al., 2002). The survey will then
progress to shallower waters in the eastern survey area before moving
to the western survey area in late October or early November 2012.
Ice conditions are expected to range from open water to 10/10 ice
cover. However, the survey cannot take place in thick multi-year ice as
both the icebreaker and seismic vessel must make continuous forward
progress at 3-4 kts. In order for the survey to proceed, areas of high
ice concentration can only consist of mostly newly forming juvenile
first year ice or young first year ice less than 0.5 m (1.6 ft) thick.
Sounds generated by the icebreaker and seismic vessel moving through
these relatively light ice conditions are expected to be far below the
high sound levels often attributed to icebreaking. These high sound
levels (>200 dB re 1 [mu]Pa [rms]) have been recorded from icebreakers
during backing and ramming operations in very heavy ice conditions and
are created by cavitation of the propellers as the vessel is slowed by
the ice or reverses direction (Erbe and Farmer, 1998; Roth and Schmidt,
2010).
Acoustic Sources
(1) Seismic Airgun Array
The seismic source used during the project would be an airgun array
consisting of 28 Sercel G-gun airguns, of which 26 would be active and
have a total discharge volume of 4,450 in\3\. The 28 airguns would be
distributed in two sub-arrays with 14 airguns per sub-array. Individual
airgun sizes range from 70 to 380 in\3\. Airguns will be operated at
2,000 psi. The seismic array and a single hydrophone streamer 4.5-9 km
(2.8-5.6 mi) in length would be towed behind the Geo Arctic. Additional
specifications of the airgun array are provided in Appendix B of ION's
IHA application.
(2) Echo Sounders
Both vessels will operate industry standard echo sounder/fathometer
instruments for continuous measurements of water depth while underway.
These instruments are used by all large vessels to provide routine
water depth information to the vessel crew. Navigation echo sounders
send a single, narrowly focused, high frequency acoustic signal
directly downward to the sea floor. The sound energy reflected off the
sea floor returns to the vessel where it is detected by the instrument,
and the depth is calculated and displayed to the user. Source levels of
navigational echo sounders of this type are typically in the 180-200 dB
re 1 [mu]PA-m (Richardson et al. 1995a).
The Geo Arctic will use one navigational echo sounder during the
project. The downward facing single-beam Simrad EA600 operates at
frequencies ranging from 38 to 200 kHz with an output power of 100-2000
Watts. Pulse durations are between 0.064 and 4.096 milliseconds, and
the pulse repetition frequency (PRF or ping rate) depends on the depth
range. The highest PRF at shallow depths is about 40 pings per second.
It can be used for water depths up to 4,000 m (13,123 ft) and provides
up to 1 cm (0.4 in) resolution.
The Polar Prince will use one echo sounder, an ELAC LAZ-72. The
LAZ-72 has an operating frequency of 30 kHz. The ping rate depends on
the water depth and the fastest rate, which occurs in shallow depths,
is about 5 pings per second.
Dates, Duration, and Region of Activity
The proposed geophysical survey would be conducted for ~76 days
from approximately October 15 to December 15, 2012. Both the Geo Arctic
and the Polar Prince entered the Alaskan Beaufort Sea from Canadian
waters in early October. The survey area will be bounded approximately
by 138[deg] to 169[deg] W. longitude and 70[deg] to 73[deg] N. latitude
in water depths ranging from <20 to >3,500 m (66 to 11,483 ft) (see
Figure 1 of ION's IHA application). For mitigation and operational
reasons the survey area has been bisected by a line that runs from
70.5[deg] N, 150.5[deg] W to 73[deg] N, 148[deg] W. Weather and ice
permitting, ION plans to begin survey operations east of the line
(eastern survey area) in offshore waters (>1,000 m [3,281 ft]) where
bowheads are expected to be least abundant in early October. The survey
will then progress to shallower waters in the eastern survey area
before moving to the west survey area in late October or early
November. The vessels will depart the region to the south via the
Chukchi and Bering Seas and arrive in Dutch Harbor in mid- to late
December.
Comments and Responses
A notice of NMFS' proposal to issue an IHA to ION was published in
the Federal Register on August 17, 2012 (77 FR 49922). That notice
described, in detail, ION's proposed 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 comments from the following organizations: the Marine Mammal
Commission (Commission), the North Slope Borough (NSB), Oceana, Ocean
Conservation Research, Ocean Conservancy, PEW Environment Group (PEW),
and a group joined by the Alaska Wilderness League, Audubon Alaska,
Center for Biological Diversity, EarthJustice, Natural Resources
Defense Council, Northern Alaska Environmental Center, Ocean
Conservation Research, Pacific Environment, Sierra Club, and World
Wildlife Fund (AWL et al.).
Any comments specific to ION's 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.
General MMPA Issues and Impact Analyses
Comment 1: The Commission recommends that NMFS continue to include
proposed incidental harassment authorization language, including the
total number of estimated takes by Level A and Level B harassment, at
the end of Federal Register notices but ensure that the language is
consistent with that referenced in the main body of the corresponding
notice.
Response: NMFS agrees with the Commission's recommendation and
will, to the extent practicable, include proposed incidental harassment
authorization language at the end of Federal Register notices. In
addition, NMFS agrees that the language should be consistent with that
referenced in the main body of the corresponding notice and will make
every effort to ensure consistency. However, the total number of
estimated takes by Level A and Level B harassment is presented in
tables
[[Page 65062]]
within the subsection Estimated Takes by Harassment of the Federal
Register notice, and it would be redundant to repeat this information
within the proposed incidental harassment authorization language
elsewhere in the same Federal Register notice.
Comment 2: The Commission recommends that NMFS propose to issue
regulations under section 101(a)(5)(A) of the MMPA and a letter of
authorization, rather than an incidental harassment authorization, for
any proposed activities expected to cause a permanent threshold shift
(PTS).
Response: The legal requirements and underlying analysis for the
issuance of an IHA concerning take do not require the issuance of
regulations and a letter of authorization in this particular case. In
order to issue an authorization pursuant to Section 101(a)(5)(D) of the
MMPA, NMFS must determine that the taking by harassment of small
numbers of marine mammal species or stocks will have a negligible
impact on affected species or stocks, and will not have an unmitigable
adverse impact on the availability of affected species or stocks for
taking for subsistence uses. If there were a potential for serious
injury or mortality, NMFS could not issue an IHA. Instead, any
incidental take authorization would need to be processed under Section
101(a)(5)(A) of the MMPA.
As described here and in previous FR notices, PTS is considered to
be injury (Level A Harassment). However, an animal would need to stay
very close to the sound source for an extended amount of time to incur
a serious degree of PTS, which could increase the probability of
mortality. In this case, it would be highly unlikely for this scenario
to unfold given the nature of any anticipated acoustic exposures that
could potentially result from a mobile marine mammal that is generally
expected to avoid loud sounds swimming in the vicinity of an airgun
array moving at 3-4 knots. Therefore, it is appropriate to issue an
incidental take authorization under 101(a)(5)(D), as we have made the
necessary findings (described elsewhere in this document) under that
Section of the MMPA.
Comment 3: The Ocean Conservancy, Ocean Conservation Research,
Oceana, and AWL et al. state the proposed seismic survey would result
in harassment takes of a large number of marine mammals, specifically
250 bowhead whales, 4,300 beluga whales, and 60,000 ringed seals, all
of which would be exposed to received levels above 160 dB (rms). Thus,
the commenters assert that NMFS cannot satisfy MMPA's small number and
negligible impact provisions.
Response: NMFS disagrees with the commenters' assessment. First, as
mentioned in the Federal Register notice for the proposed IHA (77 FR
49922; August 17, 2012) and earlier in this document, the estimated
takes of marine mammals are based on summer/fall marine mammal
densities. With most marine mammals moving out of the proposed seismic
area as winter approaches, the density would be lower and the actual
numbers of takes would be far fewer than those calculated based on fall
densities. As described in the Negligible Impact and Small Numbers
Analysis and Determination section of this document, NMFS considers the
number of authorized takes small.
As discussed in detail in the Negligible Impact and Small Numbers
Analysis and Determination section of this document, most of the takes
from ION's proposed in-ice 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, butare expected to resume their normal activities
and reoccupy the area as soon as the vessels move away. Additionally,
since the proposed icebreaking seismic survey is planned outside the
time when ice seals are giving birth and after approximately 97% of the
bowhead population is expected to have moved through the area, no
impacts on pups or calves are expected, and nor are there any orther
areas of particular importance for reproduction or feeding that could
be impacted. Therefore, any behavioral effects to ringed seals,
bowheads, or other species are not expected to have significant impacts
to individual fitness or the population. In addition, the mitigation
and monitoring measures (described previously in this document)
included in the IHA are expected to further reduce any potential
disturbance to marine mammals. Last, a small number of takes in the
form of PTS are being authorized, however, if incurred, they would be
expected to be minor in degree (low intensity--a few dBs of loss at
certain frequencies), and they are not expected because of a
combination of mitigation and likely avoidance of high source levels.
Mortality is neither authorized nor anticipated.
Therefore, NMFS believes that the take, by harassment, from ION's
in-ice seismic survey will have a negligible impacton the affected
species or stocks.
Comment 4: The Ocean Conservancy, Ocean Conservation Research, and
AWL et al. claims that NMFS failed to consider cumulative impacts
adequately. In addition, AWL et al. states that it is essential for
NMFS to consider ION's proposed survey along with the impacts of
Shell's exploratory drilling program in Beaufort and Chukchi Seas.
Response: Section 101(a)(5)(D) of the MMPA requires NMFS to make a
determination that the harassment incidental to a specified activity
will have a negligible impact on the affected species or stocks of
marine mammals, and will not result in an unmitigable adverse impact on
the availability of marine mammals for taking for subsistence uses.
Neither the MMPA nor NMFS' implementing regulations specify how to
consider other activities and their impacts on the same populations.
However, consistent with the 1989 preamble for NMFS' implementing
regulations (54 FR 40338, September 29, 1989), the impacts from other
past and ongoing anthropogenic activities are incorporated into the
negligible impact analysis via their impacts on the environmental
baseline (e.g., as reflected in the density/distribution and status of
the species, population size and growth rate, and ambient noise).
In addition, cumulative effects were addressed in the Environmental
Assessment and biological opinion prepared for this action, both of
which NMFS indicated would be completed prior to the issuance of an IHA
(77 FR 49922; August 17, 2012). The Environmental Assessment's
cumulative effects analysis included consideration of (among other
things): BP Exploration (Alasks), Inc.'s (BPXA) ocean-bottom-cable
seismic surveys in the Simpson Lagoon area of the Beaufort Sea; BPXA's
proposed Northstar oil production activity in the Beaufort Sea; and
Shell Offshore Inc.'s (Shell) proposed exploratory drilling activities
in the Beaufort and Chukchi Seas, Arctic warming, subsistence hunting,
and noise contribution from vessel traffic.
These documents, as well as the Alaska Marine Stock Assessments and
the most recent abundance estimates for the affected species, are part
of NMFS' Administrative Record for this action, and provided the
decision maker with information regarding other activities in the
action area that affect marine mammals, an analysis of cumulative
impacts, and other information relevant to the determination made under
the MMPA.
Comment 5: AWL et al. states that in determining whether to proceed
with
[[Page 65063]]
ION's request, NMFS must also consider the extent of missing
information as to both the environmental baseline in the Arctic and
marine mammal responses to noise in general.
Response: NMFS has been conducting such analyses in both aspects
since 2010 when it first received ION's IHA application.
Regarding the environmental baseline, as described in the Federal
Register notice for the proposed IHA (77 FR 49922; August 17, 2012),
where the marine mammal distribution and density data for fall and
winter seasons in the Beaufort and Chukchi Seas were not available,
NMFS used the summer and fall density data. This data is an appropriate
proxy for this analysis because it is for the same species and because
we assume it is an overestimate since animals are known to move out of
the area in the winter (Allen and Angliss 2011).
Separately, regarding marine mammal responses to noise in general
and as described in the Potential Effects of the Specified Activity on
Marine Mammals section of the proposed IHA, while there are not data
indicating the responses of every species to every specific sound
source type, we believe that the large body of available information
across multiple species and sound types allows us to reasonably
anticipate likely responses to the proposed seismic airgun and
icebreaking and make the findings necessary for issuance of this IHA.
Density Calculation and Take Estimate
Comment 6: PEW states that NMFS did not use the best available data
for impact analysis, as most survey data NMFS were collected during the
open water season that usually conclude by October.
Response: NMFS does not agree with PEW's statement that we did not
use the best available data for impact analysis. As it was discussed in
the Federal Register notice for the proposed IHA (77 FR 49922; August
17, 2012), the reason for using the fall marine mammal densities for
take calculation is because the lack of marine mammal density data in
the winter season. Nevertheless, the fall marine mammal density data
NMFS and ION used are the best available data. In addition, during the
initial impact analysis, NMFS Office of Protected Resources and ION
consulted with NMFS National Marine Mammal Laboratory (NMML) to make
sure that the marine mammal density data used for impact analysis are
the best available data. Using marine mammal summer/fall density data
results in over-estimates as the overwhelming majority marine mammals
will have likely departed the Beaufort and Chukchi Seas by the start of
winter (Mate et al. 2000; Miller et al. 2002; Frost et al. 2004; Suydam
et al. 2005; Cameron and Boveng, 2009; Christie et al. 2010; Allen and
Angliss 2011).
Comment 7: AWL et al. states that using density is unsuited for
determining bowhead take during the fall migration. AWL et al. further
argues that the bowhead whales would pass through the Beaufort and
Chukchi Sea in the fall during their migration within a migratory
corridor. AWL et al. then points out that it was not clear NMFS has
adequately considered the migration of beluga whales in the Beaufort
Sea as well. AWL et al. predicts that when taking the bowhead migration
into account could dramatically increase the estimate of harassed
whales.
Response: NMFS does not agree AWL et al.'s assessment. ION's in-ice
seismic survey would only occur after the majority of bowhead and
beluga whales have migrated out of the Beaufort Sea. In addition, as
noted in the Federal Register notice for the proposed IHA (77 FR 49922;
August 17, 2012), ION would start its seismic survey from the east and
proceed westward, thereby overlapping with the fewest possible number
of marine mammals later in the season. Therefore, using summer/fall
marine mammal density to calculate takes in the Arctic when most
animals have left the area is a reasonable and scientifically
supportable approach, although, as stated it will result in an over-
estimate of takes.
Comment 8: The Commission requests NMFS require ION to (1) consult
with NMFS National Marine Mammal Laboratory (NMML) and other
researchers and revise its expected density estimates for gray whales
and bearded seals to reflect new information from passive acoustic
recordings, and (2) include, as appropriate, an estimate of takes by
Level A harassment for those species. Citing Stafford et al. (2007),
Wang and Overland (2009), Shelden and Mocklin (2012), the Commission
points out that acoustic data show that these species are present
throughout the winter months. The NSB also expresses its concern that
bowhead and gray whales may remain in the area much longer than
previously thought. Oceana is also concerned that there could be Level
A takes of bearded seals, though it recognizes that much of the bearded
seal population will have already migrated into the Bering Sea.
Response: NMFS' Office of Protected Resources and ION worked
extensively with NMFS' NMML on density estimates for all marine mammals
(gray whales and bearded seals included) that could occur in the
proposed survey area. The approaches took into account the best
available scientific data on the abundance of marine mammals (gray
whales and bearded seals included) that could potentially occur through
the winter season, as well as estimates erred on the overestimation.
NMFS and ION conducted a thorough review of acoustic recordings data
pertaining to overwintering marine mammals (e.g., Stafford et al. 2007;
Roth 2008; MacIntyre and Stafford 2011; Shelden and Mocklin 2012). We
concluded that although some marine mammals were detected in the
Beaufort and Chukchi Seas during this time, none of the studies allowed
us to identify specific density estimates. In addition, many studies
show that marine mammal calling rates dropped significantly during the
winter months (Roth 2008; MacIntyre and Stafford 2011), which is
consistent with our prediction based on tagging research (Cameron and
Boveng 2009; Harwood et al. 2012). The notion is also shared by Oceana
as it stated in its comment that much of the population of bearded
seals will have already migrated into the Bering Sea. These reviews
support our initial analyses and the basis for marine mammal take
estimates. Therefore, we do not believe it is necessary, nor is it
feasible, to revise density estimates or to include gray whales and
bearded seals in the Level A take estimates.
Finally, we acknowledge that bowhead and gray whales may remain in
the Beaufort and Chukchi Seas during the timeframe of ION's proposed
survey. To account for this possibility, NMFS relied on summer/fall
data to estimate potential abundance of these species, which resulted
in an over-estimate of take.
Comment 9: The Commission requests NMFS require ION to recalculate
expected densities for bowhead whales based on (1) the corrected
decrease in abundance of bowhead whales reported by Miller et al.
(2002) for early and late October (i.e., 78 percent) and (2) any
additional information from more recent surveys, including acoustical
surveys, conducted by NMFS' NMML and other researchers to assess the
distribution and relative abundance of bowhead whales in the survey
area from October through December.
Response: Through the process of analyzing the potential impacts of
ION's in-ice seismic survey in the Beaufort and Chukchi Seas, NMFS'
Office of Protected Resources and ION worked extensively with NMFS'
NMML on marine mammal density estimates, including distribution and
densities of
[[Page 65064]]
bowhead whales. The early October (October 1-15) bowhead abundance of
0.55 bowheads/100 km and the late October (October 15-31) abundance of
0.12 bowheads/100 km reported in Miller et al. (2002) were both
calculated as overall averages across the four survey regions and all
water depth strata. The reference density to which the 90% decrease
from early October to late October adjustment was applied was based
only on bowhead sightings in less than 200 m of water. Thus, data in
table Appendix 9.1 in Miller et al. (2002), which excludes water depths
>200 m, were used for the calculation. In that table, the mean number
of bowheads/100 km seen from October 1-15 was 0.618 and the mean for
October 16-31 was 0.089. This represents an 86% decrease from early to
late October, which was rounded to 90%.
If the percentage decrease were left unrounded the average density
for water depths <200 m in the Eastern Beaufort Sea in Table 2 of the
ION's IHA application would become 0.0132 bowheads/km\2\. Using this
value the take calculations would be 282, instead of the 201 stated in
the Federal Register notice for the proposed IHA (77 FR 49922; August
17, 2012).
NMFS and ION by focused on bowhead whale aerial surveys that were
conducted in the spring of 2011 and 2012. We ultimately agreed that the
aerial survey data being used for density calculations was the most
appropriate and that any newer data (i.e. from 2011 surveys) was of no
added value. More recent aerial survey data were not used for the
direct calculation of densities in late October as there have been very
few surveys conducted at that time of year in the eastern U.S. Beaufort
in recent years. Although acoustic data can be useful in assessing
distribution, and to a limited extent, relative abundance, however, as
with acoustic data for other marine mammals, none of them provides a
basis for density estimates.
Comment 10: The Commission requests NMFS provide stronger assurance
that the actual number of takes would be negligible by (1) estimating
the expected number of takes plus some measure of uncertainty in that
estimate, (2) using maximum estimated densities of the marine mammals
in the survey area to estimate takes, or (3) using some comparable
approach that accounts for uncertainty and provides a high level of
assurance that the actual taking would, in fact, be negligible. In
addition, the Commission requests NMFS require ION to account for all
sources of uncertainty in its estimation approach, including animals
that may be present but not observed. Oceana and the NSB also express
their concerns regarding the uncertainty of the impacts to marine
mammals from ION's in-ice seismic survey during the winter season.
Response: NMFS believes that the analyses provided in the Federal
Register notice for the proposed IHA (77 FR 49922; August 17, 2012) has
already provided a well-founded assurance that the impacts from even
the overestimated takes, which were based on summer-fall marine mammal
density, would be negligible to marine mammal species and stocks in
ION's in-ice seismic survey areas in the Beaufort and Chukchi Seas, and
that the take would not have unmitigable impacts to subsistence use of
these species and stocks. These analyses already took uncertainties of
marine mammal winter distribution and densities into account and erred
on the side of caution.
The determination regarding whether the total taking would have a
negligible impact on the species or stocks is based on the species-
specific average density, or based on allotted number from past chance
occurrence, as described above and in the proposed Federal Register
notice for the proposed IHA (77 FR 49922; August 17, 2012). More
importantly, the negligible impact analysis is not simply an assessment
of the number of takes, but rather includes consideration of the
nature, context, and likely severity of the takes, as well as the
anticipated effectiveness of the mitigation measures. As described
later in this document, our analysis allowed us to determine that the
total taking would have a negligible impact on the affected species.
Regarding the requirement for ION to account for all sources of
uncertainty in its estimation approach, including animals that may be
present but not observed, NMFS believes that all population survey
studies, as well as density estimates, take into account for marine
mammals not observed during the survey.
Acoustic Impacts
Comment 11: PEW states that NMFS needs to ensure that best science
is used when considering permitting an IHA to authorize Level A
harassment of marine mammals, since this is the first time Level A take
is being proposed.
Response: NMFS has relied on the best available scientific
information to support the issuance of ION's authorization. In the case
of authorizing Level A harassment, NMFS has estimated that no more than
1 bowhead whale, 3 beluga whales, and 4 ringed seals could, although
unlikely, experience minor permanent threshold shifts of hearing
sensitivity (PTS). The available data and analyses, as described more
fully in the proposed IHA, include extrapolation results of many
studies on marine mammal noise-induced temporary threshold shifts of
hearing sensitivities (TTS) (Kryter 1985; Richardson et al. 1995;
Kastak et al. 1999; Schlundt et al. 2000; Finneran et al. 2002; 2005;
Nachtigall et al. 2003; 2004; Kastak et al. 2004; 2005; Southall et al.
2007; Mooney et al. 2009a; 2009b; Finneran et al. 2010a; 2010b). An
extensive review of TTS studies and experiments prompted NMFS to
conclude that possibility of minor PTS in the form of slight upward
shift of hearing threshold at certain frequency bands by a few
individuals of marine mammals is extremely low, but not unlikely.
Comment 12: Citing NMFS' 1995 Federal Register notice (60 FR
28379), AWL et al. argues that since the proposed seismic survey has
the potential to cause permanent hearing loss in marine mammals, the
impact must constitute ``serious injury.'' Ocean Conservancy also
states that PTS equals ``serious injury''. AWL et al. further states
that marine mammals enter the 180/190 dB re 1 [micro]Pa exclusion zones
have at least the potential to suffer serious injury, and thus AWL et
al. assumes that at least 23 beluga whales, 6 bowhead whales, and 277
ringed seals could potentially suffer serious injury as a result of the
survey. Oceana also expresses its concern that serious injury could
occur to marine mammals.
Response: Our understanding of noise-induced impacts on marine
mammals has evolved over the past two decades and we no longer believe,
based on the best available data, that PTS equals ``serious injury.''
As described in detail in the Federal Register notice for the proposed
IHA (77 FR 49922; August 17, 2012), the potential Level A takes would
be limited to minor degrees of PTS by 1 bowhead whale, 3 beluga whales,
and 4 ringed seals. This level of injury is different from ``serious
injury,'' which is defined as ``any injury that will likely result in
mortality'' (50 CFR 229.2).
Noise-induced threshold shifts (TS, include PTS) are defined as
increases in the threshold of audibility (i.e., the sound has to be
louder to be detected) of the ear at a certain frequency or range of
frequencies (ANSI 1995; Yost 2000). Several important factors relate to
the magnitude of TS, such as level, duration, spectral content
(frequency range), and temporal pattern (continuous, intermittent) of
exposure (Yost 2000; Henderson et al. 2008). TS occurs in terms of
frequency range
[[Page 65065]]
(hertz [Hz] or kHz), hearing threshold level (dB), or both frequency
and hearing threshold level (CDC 2004).
In addition, there are different degrees of PTS: Ranging from
slight/mild to moderate and from severe to profound (Clark 1981).
Profound PTS or the complete loss of the ability to hear in one or both
ears is commonly referred to as deafness (CDC 2004; WHO 2006). High-
frequency PTS, presumably as a normal process of aging that occurs in
humans and other terrestrial mammals, has also been demonstrated in
captive cetaceans (Ridgway and Carder 1997; Yuen et al. 2005; Finneran
et al. 2005a; Houser and Finneran 2006; Finneran et al. 2007a; Schlundt
et al. 2011) and in stranded individuals (Mann et al. 2010).
In terms of what is analyzed for the potential PTS (Level A
harassment) in marine mammals as a result of ION's in-ice seismic
survey, if it occurs, NMFS has determined that the levels would be
slight/mild because research shows that most cetaceans (and
particularly Arctic cetaceans) show relatively high levels of avoidance
when received sound pulse levels exceed 160 dB re 1 [mu]Pa (rms)
(review in Richardson et al. 1995; Southall et al. 2007), and it is
uncommon to sight Arctic cetaceans within the 180 dB radius, especially
for prolonged duration. Results from monitoring programs associated
with seismic activities in the Arctic have shown significant responses
by cetaceans at levels much lower than 180 dB. These results have been
used by agencies to support monitoring requirements within distances
where received levels fall below 160 dB and even 120 dB. Thus, very few
animals would be exposed to sound levels of 180 dB re 1 [mu]Pa (rms)
regardless of detectability by protected species observers. Avoidance
varies among individuals and depends on their activities or reasons for
being in the area, and occasionally a few individual Arctic cetaceans
will tolerate sound levels above 160 dB. Tolerance of levels above 180
dB is infrequent, regardless of the circumstances. Therefore, a
calculation of the number of cetaceans potentially exposed to >180 dB
that is based simply on density would be a gross overestimate of the
actual numbers exposed to 180 dB. Such calculations would be misleading
unless avoidance response behaviors were taken into account to estimate
what fraction of those originally present within the soon-to-be
ensonified to >180 dB zone (as estimated from density) would still be
there by the time levels reach 180 dB.
Comment 13: The Ocean Conservancy and AWL et al. state that NMFS'
analysis underestimated the impact of stress and the effects of airguns
on bowhead whales.
Response: NMFS does not agree with the assessment. The Federal
Register for the proposed IHA (77 FR 49922; August 17, 2012) provided
an analysis of the potential stress response to marine mammals (bowhead
included) that could result from ION's in-ice seismic survey. However,
almost no information is available on sound-induced stress in marine
mammals, or on its potential (alone or in combination with other
stressors) to affect the long-term well-being or reproductive success
of marine mammals (Fair and Becker 2000; Hildebrand 2005; Wright et al.
2007a, 2007b). Nevertheless, extrapolation of information regarding
stress responses in other species is applicable because the responses
are highly consistent among all species in which they have been
examined to date, especially considering that marine mammals will
likely respond in a manner consistent with other species studied
(Wright et al. 2007a). In the section discussing non-auditory effects,
NMFS summarized that a range of issues may arise from an extended
stress response from noise exposure, which include suppression of
reproduction (physiologically and behaviorally), accelerated aging and
sickness-like symptoms. Such long-term effects, if they occur, would be
mainly associated with chronic noise exposure, which is characteristic
of some seismic surveys and exposure situations (McCauley et al. 2000b;
Nieukirk et al. 2009) but not of some others. As described in the
Federal Register notice for the proposed IHA (77 FR 49922; August 17,
2012), ION's in-ice seismic survey would be performed in a limited area
for a short duration (a total 76 days). In addition, the source vessel
would be in constant movement as it acquires seismic data and [would
not overlap with individuals for a substantial period of time].
Therefore, we have concluded that marine mammals would not suffer from
chronic and long-term, noise exposure.
In addition, NMFS provided more detailed analyses on noise-induced
stress in its EA for the issuance of an IHA to ION (NMFS 2012), which
also included three specific studies concerning marine mammals (Thomas
et al. 1990; Romano et al. 2004; Rolland et al. 2012). These studies
point out that short-term noise exposure, such as those animals being
tested for TTS, only induced stress-immune system change during intense
noise exposure (Romano et al. 2004), while during playbacks of recorded
drilling noise to four captive beluga whales showed no changes in blood
levels of stress-related hormones (Thomas et al. 1990).
Comment 14: Citing Lucke et al. (2009) TTS experiment on a harbor
porpoise, the AWL et al. points out that a harbor porpoise experienced
TTS when exposed to airgun noise at 164 dB, a significantly lower level
than what NMFS predicts.
Response: NMFS does not agree with AWL et al.'s assessment. AWL et
al. erroneously interpreted the results of the TTS-induced sound
exposure level (SEL) in Lucke et al. (2009) to be sound pressure level
(SPL) that NMFS uses for the threshold of PTS. In their paper, Lucke et
al. (2009) found a threshold shift (TS) of a harbor porpoise after
exposing it to airgun noise with peak-to-peak (pk-pk) received SPL at
200.2 dBpk-pk re 1 [mu]Pa, which according to the authors,
corresponds to SEL of 164.5 dB re 1 [mu]Pa\2\s after integrating
exposure. It is important to understand that SPL and SEL are two very
different ways to express the relative sound intensity. NMFS currently
uses root-mean-square (rms) of received SPL at 180 dB and 190 dB re 1
[mu]Pa as the threshold above which PTS could occur for cetaceans and
pinnipeds, respectively, and that TTS is thought to occur below these
levels. However, TTS experiments so far have shown that in almost all
cases TTS would occur at levels much higher than the 180 and 190 dB re
1 [mu]Pa thresholds. It is difficult to determine the equivalent of rms
SPL from the reported pk-pk SPL in Lucke et al. (2009) because the
airgun noise is a broadband impulse. Although it is a standard practice
to subtract 9 dB from pk-pk SPL of a sinusoidal signal to convert it to
rms SPL, for boardband signal from seismic surveys, the difference
could be as large as 16 dB (Harris et al. 2001; McCauley et al. 2000).
If we applied the 16 dB difference and convert the pk-pk reported in
Lucke et al. (2009), the rms SPL for harbor porpoise to experience TTS
would be 184 dB re 1 [mu]Pa, and the received levels associated with
PTS (Level A harassment) would be higher than that. This is still above
NMFS 180 dBrms re 1 [mu]Pa threshold for injury.
Nevertheless, NMFS recognizes that the TTS threshold of harbor
porpoise is lower that other cetacean species (bottlenose dolphin and
beluga whale) tested (e.g., Finneran et al. 2002), and is discussed in
the Federal Register notice of the proposed IHA (77 FR 49922; August
17, 2012), as well as the EA for the issuance of the IHA to ION (NMFS
2012).
Comment 15: Citing Kastak et al. (2008) and Jujawa and Liberman
(2009), AWL et al. states that anthropogenic sound can induce PTS at
lower levels
[[Page 65066]]
than anticipated. In addition, AWL states that new data indicate that
mid-frequency cetaceans, such as bottlenose dolphins and beluga whales
have greater sensitivity to sounds within their best hearing range than
was supposed at the time Southall et al. (2007) was published.
Response: NMFS agrees that PTS could occur at relatively lower
levels, such as at levels normally would only cause TTS, if the animal
experiences repeated exposures at very close distances to the sound
source. These long term effects are well known in terrestrial mammals
(Yost 2000; Henderson et al. 2008) and is acknowledged in the Federal
Register notice for the proposed IHA (77 FR 49922; August 17, 2012)
that repeated exposure to elevated noise that causes TTS could
eventually result in PTS. However, as mentioned in detailed in the
proposed IHA, ION's in-ice seismic survey would be performed in a
limited area for a short duration of a total 76 days. In addition, the
source vessel would be in constant movement as it acquires seismic data
and any overlap between the vessel and affected species would be
minimal and short-lived. Therefore, NMFS considers it highly unlikely
many animals would be repeatedly exposed to received levels that would
cause TTS.
As far as the hearing sensitivity of mid-frequency cetaceans is
concerned, it is well known that mid-frequency cetaceans have greater
sensitivity to sounds within their best hearing ranges, which are
typically between 10-100 kHz (Johnson 1967; Hall and Johnson 1972;
White et al. 1978; Awbrey et al. 1988; Johnson et al. 1989; Ridgway et
al. 2001). Further TTS research on a bottlenose dolphin exposed to pure
tones suggests that mid-frequency cetacean tends to be more vulnerable
(in terms of TTS occurrence) at their most sensitive hearing range
(Finneran et al. 2010). However, the majority of acoustic energy from a
seismic airgun, vessel and icebreaking noise is under 1 kHz (Richardson
et al. 1995), which is expected to have less impact on the most
sensitive hearing ranges of these cetaceans.
Comment 16: AWL et al. argues that NMFS' justifications for the use
of a correction factor of only counting 10% marine mammals being
exposure to received levels at Level A would show no avoidance and thus
subject to PTS and that exposure will only be brief are both flawed and
unsupported by survey data and scientific evidence. Citing Arctic
seismic survey monitoring and mitigation reports from previous years,
AWL et al. states that marine mammals, especially ice seals, do not
always avoid loud noises, and that marine mammals routinely stray too
close to the airguns, even during daylight hours. The Commission also
requests NMFS require ION provide a scientific basis for any
conclusions about the animals' responses to the airguns. The Commission
further requests NMFS require ION to revise the estimated number of
Level A harassment takes to include all marine mammals that may be
exposed to source levels greater than or equal to 180 and 190 dB re 1
[mu]Pa for cetaceans and pinnipeds, respectively.
Response: NMFS does not agree with AWL et al.'s assessment. As
discussed earlier in the response to Comment 13, NMFS' current Level A
take threshold of 180 dB re 1 [mu]Pa for cetaceans is appropriate.
Marine mammals found in these zones are not expected to experience TTS
(a form of Level B Harassment), much less PTS (Level A Harassment) even
if they are exposed to a few seismic impulses. On the other hand,
almost all marine mammals that underwent TTS experiments showed strong
aversive behavioral reactions when the received noise levels approached
to levels that could cause TTS (e.g., Nachtigall et al. 2004; Fineran
and Schlundt 2004; Lucke et al. 2009), despite the fact that these
animals are trained and food-reinforced to participate the studies.
Simply because previous seismic survey monitoring reports reveal that
marine mammals were observed in the exclusion zones does not mean the
animals necessarily experienced TTS, much less PTS..
The 10% correction factor used by NMFS is appropriate for
estimating likely Level A Harassment takes, since there is evidence
suggesting that most, if not all, marine mammals would avoid the noise
levels that could cause immediate PTS (as described in the Estimated
Take section below.
NMFS does not agree with the Commission's recommendation. Again,
there is a difference between potential TTS (Level B Harassment),
potential PTS (Level A Harassment) and serious injury. As described in
detail in the response to Comment 13, the 180/190 dB re 1 [mu]Pa are
the current standards used to prevent marine mammals from experiencing
injury, which is equated with PTS, not TTS, which occurs at
substantively lower received levels than PTS. In fact, all studies on
marine mammal TTS have pointed out that TTS occurs at a received levels
higher than NMFS current 180/190 dB re 1 [mu]Pa threshold (e.g.,
Finneran et al. 2000; 2002; Lucke et al. 2009). Even if the animal is
exposed multiple times at levels higher than the 180/190 dB re 1 [mu]Pa
threshold and receives TTS, it is not considered physical injury. TTS,
which is also referred to as auditory fatigue, is a reversible hearing
threshold shift and it often recovers within minutes to hours (Ward
1997; Finneran et al. 2000; 2002). The numbers AWL et al. cited in
their comment are the estimates of marine mammals that could occur
within NMFS 180/190 dB re 1 [mu]Pa exclusion zones, which do not
represent the number of animals that would receive TTS, not to mention
PTS. In fact, NMFS considers in most cases all animals would avoid
staying within the zones long enough to receive TTS. Therefore, most
marine mammals will not experience TTS, which means the occurrence of
PTS would be even lower.
Finally, even if the animal receives PTS, this does not equate to
serious injury. As stated earlier in response to Comment 13, NMFS
defines injury as ``any injury that will likely result in mortality''
(50 CFR 229.2), which, based on the best available science and NMFS'
judgment, does not include PTS. .
Comment 17: The AWL et al. states that the current NMFS 160-dB re 1
[mu]Pa threshold for Level B harassment is arbitrary and non-
conservative. Citing papers by Clark and Gagnon (2006), Risch et al.
(2012), Bain and Williams (2006), Miller et al. (1999; 2005), the AWL
et al. argues that in many cases marine mammals respond to much lower
noise levels.
Response: NMFS does not agree with AWL et al.'s assessment, as the
papers AWL cited do not necessarily indicate that the animals exposed
under the certain received levels constitute a ``take'' as defined
under the MMPA. Clark and Gagnon (2006) reported that fin whales
(Balaenoptera physalus) in the northeast Pacific Ocean went silent for
an extended period starting soon after the onset of a seismic survey in
the area, and Risch et al. (2012) reported that humpback whale
(Megaptera novaeangliae) song in the Stellwagen Bank National Marine
Sanctuary was reduced, concurrent with transmissions of an Ocean
Acoustic Waveguide Remote Sensing experiment that produced series of
frequency modulated pulses approximately 200 km away in the Gulf of
Maine. Although Miller et al. (1999) reported that bowhead whale
deflection may occur about 35 km (21.7 mi) to the east of the seismic
operations, no SPL measurement to that distance was provided, except
noting that received levels at 30 km (18.6 mi) were about 107-126 dB re
1 [mu]Pa rms, depending on propagation. In addition, Miller et al.
(2005) and Bain and Williams (2006) observed that marine mammal
densities were generally lower
[[Page 65067]]
during seismic surveys and were seen moving away from seismic sources,
even in areas where received levels were far below 160 dB re 1 [mu]Pa.
Nevertheless, Miller et al. (2005) noted that bowhead whales have been
sighted within the ``safety radius'' without any observed behavioral
responses.
To address these observations, it is important to understand that
the vocal behaviors shown by fin and humpback whales, as reported by
Clark and Gagnon (2006) and Risch et al. (2012), are considered to be
related to mating activities, which do not apply to bowhead whales and
other marine mammal species in the Beaufort and Chukchi Seas during
ION's in-ice seismic survey. Second, as stated in the past, NMFS does
not believe that minor course corrections during a migration or
temporarily moving away from seismic source, as observed by Miller et
al. (1999; 2005) and Bain and Williams (2005) 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 [micro]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., a reaction 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).
Based on the information and data summarized in Southall et al.
(2007), and on information from various studies, NMFS believes that the
onset for behavioral harassment is largely context dependent, and there
are many studies showing marine mammals do not show behavioral
responses when exposed to multiple pulses at received levels above 160
dB re 1 [micro]Pa (e.g., Malme et al. 1983; Malme et al. 1984;
Richardson et al. 1986; Akamatsu et al. 1993; Madsen and M[oslash]hl
2000; Harris et al. 2001; Miller et al. 2005). Therefore, although
using a uniform SPL of 160-dB for the onset of behavioral harassment
for impulse noises may not capture all of the nuances of different
marine mammal reactions to sound, it is an appropriate way to manage
and regulate anthropogenic noise impacts on marine mammals. Therefore,
unless and until an improved approach is developed and peer-reviewed,
NMFS will continue to use the 160-dB threshold for determining the
level of take of marine mammals by Level B harassment for impulse noise
(such as from airguns).
Comment 18: Citing the Expert Panel Review of Statoil and ION's
2011 monitoring plans, the AWL et al. states that the noise from
seismic airgun arrays as ``a mixed impulsive/continuous noise source''
and that ``NMFS should evaluate its impacts on that basis.''
Response: NMFS does not agree with the AWL et al.'s statement.
First, nowhere in the Expert Panel's report did it states that airgun
sound is ``a mixed impulsive/continuous noise source''. It has been
well understood that the source characteristics from a seismic airgun
(or airgun array) are impulsive, with no continuous acoustic components
(Richardson et al. 1995). What the Expert Panel stated in its report is
that ``seismic airgun signals should not be treated as truly impulsive
when received at ranges where sound propagation is known to remove the
impulsive nature of these signals'', which means that the signals
become ``stretched'' at very large distance due to reverberation and
multipath propagation. Furthermore, the Expert Panel stated that
``[o]ver very short ranges where potential hearing loss (temporary or
permanent) can occur, airgun impulses retain their impulsive features
and should be considered as impulses.''
Although it has been known that at long distances an impulse
acoustic signal will lose its pulse feature by stretching its duration
due to multipath propagation, these signals (or noises) are still
fundamentally different from other non-impulse noise sources such as
those from vibratory pile driving, drilling, and dredging based on the
following characteristics:
First, the elongated pulse signals from the airgun array at far
distances are caused by multipath propagation in a reverberant
environment (Greene and Richardson 1988; Richardson et al. 1995; Madsen
et al. 2002; Lurton 2002), which is different from other non-pulse
signals at closer distances, which is composed of mostly direct sound.
The reverberation part of the sound in the ocean behaves differently
compared to the direct sound and early surface and bottom reflections
from the perspective of the receiver. The direct sound and early
reflections follow the inverse square law, with the addition of
absorption effects in the case of early reflections, and so their
amplitude varies with distance. However the reverberant part of the
sound remains relatively constant up to a large distance with the
position of the receiver. Therefore, as distance increases from the
source, the component of reverberant sounds increases against the
direct sound. In addition, the reverberant energy is less directional
and is distributed more uniformly around the ambient environment of the
animal. As shown in human psychoacoustics, these characteristics in a
reverberant field provide distance cues to the listener as to how far
away the source is located (Howard and Angus 2006). Therefore, at a
distance where the airgun signals have been ``stretched'' to non-pulse,
the receiving animals would be able to correctly perceive that these
sounds are coming from far away, and would thus be less likely to be
affected behaviorally as behavior responses are not solely dependent on
received levels. Other factors such as distance to the source, movement
of the source, source characteristics, and the receiver's (i.e.,
animal's) age, sex, motivation states, and prior experience, etc.
probably play more significant roles in determining the responses of
the animals that are
[[Page 65068]]
being exposed to lower levels of noises than solely the received sound
level.
Second, even though during horizontal propagation, the initial
short pulse could be ``stretched'' from milliseconds when emitted to
about 0.25-0.5 second long at a few kilometers in shallow water
(Richardson et al. 1995), the noise duration is still very short when
compared to those ``conventional'' non-pulse noise sources (vibratory
pile driving, drilling, and dredging, etc.) for which NMFS applies a
120 dB threshold for assessing behavioral harassment. The empirical
measurements of a 3,000 in3 airgun array received signal
characteristics showed that its pulse duration was stretched to 0.2
second at approximately 1.3 km (0.8 mi), to 0.5 second at approximately
10 km (6.2 mi), and to about 1.8 seconds at 80 km (50 mi) from the
source (O'Neill et al. 2011). Based on the airgun array's firing rate
of 0.1 Hz (1 shot every 10 seconds), the duty cycle was only 18% for
the signal at 80 km (50 mi) (1.8 seconds on for every 10 seconds).
Conversely, the ``conventional'' non-pulse noises from vibratory pile
driving, drilling, and dredging typically last much longer (minutes to
hours) with very brief (seconds for vibratory pile driving) intervals.
Therefore, NMFS does not agree that it is appropriate to treat
elongated airgun pulses at long distances as a ``conventional'' non-
pulse signal and apply the 120 dB behavioral response threshold to that
received sound.
Comment 19: Citing Madsen (2005), the AWL et al. states that ``the
threshold's basis in the root mean square (``RMS'') of sound pressure,
rather than in peak pressure, is non-conservative.'' The AWL et al.
further claims that studies have criticized the use of RMS for seismic
sound because of the degree to which pulsed sounds must be
``stretched,'' resulting in significant potential underestimates of
marine mammal take. The AWL et al. predicts that if NMFS would modify
its threshold estimates to use the peak pressure level instead of RMS,
the estimated number of marine mammal takes could be significantly
higher than the number of takes NMFS intends to authorize in for this
survey.
Response: NMFS does not agree with the AWL et al.'s statement.
First, there is no scientific basis that the use of root-mean-square
(rms) for sound pressure is less conservative than using peak pressure
(which includes zero-peak pressure and peak-peak pressure). All of
these are valid terms to express acoustic pressure and other physical
oscillations (e.g., alternating electrical current). NMFS chooses to
use rms because it was first established to regulate underwater noise
impacts to marine mammals and that rms uses the product mean of
acoustic pressures, which provides a more consistent result when
dealing with multiple impulses such as pile driving. For a sinusoidal
signal, the relationship between rms level and peak pressure level is
that the rms level of a given sinusoidal signal is always 3 dB lower
than the zero-peak level, and 9 dB lower than the peak-peak level.
Therefore, for example, if the peak levels would be used to set the
threshold for marine mammal disturbance, it would be 163 dB re 1
[micro]Pa (0-peak) or 169 dB re 1 [micro]Pa (peak-peak), instead of the
current 160 dB re 1 [micro]Pa (rms).
Second, it is not true that the use of rms for calculating the
levels of seismic impulse, or any other acoustic impulse, the pulsed
sound ``must be stretched''. The concern raised by Madsen (2005) was
the perceived lack of a standardized window for calculating the rms
levels during averaging. Citing a 2003 Federal Register notice (68 FR
9991; March 3, 2003), Madsen (2005) stated ``[t]he rms measure
critically relies upon choosing the size of averaging window for the
squared pressures. Derivation of this window is not standardized, which
can lead to 2-12 dB differences in rms sound pressure for the same wave
form.'' However, NMFS actually uses a standard 90% energy window when
performing rms calculation for impulse sounds.
Comment 20: The Ocean Conservation Research is concerned that
acoustic impacts on the habitat, especially other marine organisms were
not analyzed. In addition, citing Roth et al. (2012), the Ocean
Conservation Research points out that the overall ambient noise levels
could increase by 8 dB as a result of the seismic survey.
Response: NMFS does not agree with the Ocean Conservation
Research's assessment. The Federal Register notice for the proposed IHA
(77 FR 49922; August 17, 2012) provided an analysis on the potential
impacts of marine mammal habitat. The acoustic impacts on other marine
organisms in the context of their value in marine mammal habitat,
including planktonic species, invertebrates, and fish species are
further analyzed in detail in the Environmental Assessment for the
issuance of the IHA. Regarding the Ocean Conservation Research's
concern of the raising ambient noise due to seismic survey in the
Arctic, NMFS agrees that such concerns are valid, as was reported by
Roth et al. (2012) that the average ambient noise in the Chukchi and
Beaufort Seas increased by 2-8 dB in September and early October in all
years between 2006 and 2009. However, ION's in-ice seismic survey is
short in duration, will be confined to a limited area, and will occur
from mid- to late-October through December, outside the time period of
concern. The overall impact to the Beaufort and Chukchi Sea ecosystem,
including marine mammal habitat, is not expected to be significant.
Monitoring and Mitigation Issues
Comment 21: PEW states that NMFS should exclude important habitat
from the survey area and institute time- and place-based restriction
before permitting activities. Especially, PEW requested NMFS consider
excluding Hanna and Herald Shoals, the Barrow Canyon, and the Chukchi
Sea ice lead system.
Response: Although the Hanna Shoals are located in the U.S. EEZ,
the majority of the Herald Shoals are located in the Russian EEZ.
Nevertheless, both areas are outside ION's seismic survey area.
Although Barrow Canyon, which is on the edge of the proposed in-ice
seismic survey boundary, is considered as an important feeding area for
bowhead whales primarily due to its high productivity, it is only
important to marine mammals during the open water summer and early fall
seasons, which ends in September (Suydam et al. 2005; Ashjian et al.
2010; Moore et al. 2010). The Chukchi Sea ice lead system along the
entire Alaskan coastline serves as an important corridor for migrating
marine mammals such as bowhead whales, especially during the spring
(Braham et al. 1980). PEW even acknowledged in its comments to NMFS on
the draft Environmental Impact Statement (EIS) on the Effects of Oil
and Gas Activities in the Arctic Ocean (NMFS 2012a) that the bowhead
whale population ``travels along the Chukchi Sea coast during spring
months, from March through June.'' In addition, it is well known that
bowhead whale fall migration does not necessarily follow the lead
system (Huntington and Quakenbush 2009; Quakenbush et al. 2010; Allen
and Angliss 2011). Considering that ION's in-ice seismic survey is
designed specifically to avoid encountering large numbers of marine
mammals after the majority of the animals have migrated out of the
Beaufort and Chukchi Seas, NMFS does not believe that time and area
restrictions are scientifically supportable or would provide any
meaningful benefit to marine mammals.
Comment 22: AWL et al. claims that NMFS did not fully consider the
impacts of ION's survey on migrating bowhead whale mother and calf
pairs,
[[Page 65069]]
as cows and calves are known to favor the tail end of the spring and
fall migrations. Citing NMFS 2008 and 2011 Biological Opinions, AWL et
al. states that females with young bowhead whales are more responsive
to noise and human disturbance than other and that cow/calf pairs
typically migrate through the area later in the season (i.e., late
September/October). AWL et al. points out that in 2006 NMFS required a
120-dB exclusion zone for four or more cow-calf pairs to reduce impacts
on mother-calf pairs. In addition, the Commission also recommends NMFS
require ION to establish and monitor adequately both a 160- and 120-dB
re 1 [micro]Pa disturbance zone around all sound sources and to not
initiate or continue an activity if (1) an aggregation of bowhead
whales or gray whales (12 or more whales of any age/sex class that
appear to be engaged in a non-migratory, significant biological
behavior (e.g., feeding, socializing)) is observed within the 160-dB re
1 [micro]Pa, or (2) a female-calf pair is observed within the 120-dB re
1 [micro]Pa zone.
Response: NMFS recognizes that bowhead cow and calf pairs are more
prone to human disturbance than other individuals, and that they
normally follow the tail-end of the migration. However, as discussed in
the Federal Register notice for the proposed IHA (77 FR 49922; August
17, 2012), ION's in-ice seismic survey will occur in the very latter
part of the bowhead whale season (beginning after mid-October) and we
expect very few exposures. Research indicates that on average about 97%
of the bowhead whales would have passed through eastern of the Beaufort
Sea by October 15 (Miller et al. 2002), and that all studies point that
majority of the bowhead whales will be out of the Beaufort and Chukchi
Seas (Allen and Angliss 2011). More importantly, ION plans to conduct
its survey in an east to west fashion (the fall migration of bowhead
whales occurs in an east to west direction), which would further reduce
the potential takes of the few remaining whales. In addition, as
discussed in the Federal Register notice for the proposed IHA (77 FR
49922; August 17, 2012) and in the Environmental Assessment, daylight
hours during ION's in-ice seismic survey would be very limited, which
makes aerial surveys unfeasible. Therefore, based on our knowledge of
bowhead whale migration and the practicability in carry out the
monitoring and mitigation measures, NMFS will not require ION implement
the 120-dB exclusion zone for cow-calf pairs nor the 160-dB exclusion
zone for an aggregation of 12 or more whales, and concludes that the
potential impacts to bowhead whale cow-calf pairs are extremely
unlikely.
Comment 23: AWL et al. states that NMFS should require ION provide
additional clarification about the location and timing of its
surveying. AWL et al. points out that the proposed IHA describes the
surveying as beginning in deeper water (>1,000 m) in the eastern half
of the survey area before moving to the west in late October or early
November. AWL et al. states that bowhead migration has the potential to
extend into late October and even November. AWL et al. further states
that NMFS must specify the earliest date at which ION may survey in
more shallow waters near the migration corridor, and include the
specific timing of ION's operation in its conclusions and
recommendations.
Response: NMFS believes that ION's survey plan is adequately
described in its application and the Federal Register notice for the
proposed IHA (77 FR 49922; August 17, 2012). ION entered the U.S.
Beaufort Sea survey area from Canadian waters in early October and
plans to begin data collection in mid-October 2012. Therefore, the
actual seismic survey would not start until after mid-October due to
logistical delays. Weather and ice permitting, ION plans to begin
survey operations east of the Beaufort Sea and in offshore waters
(>1,000 m [3,281 ft]) where bowheads are expected to be least abundant
in mid-October. This operational plan is based on the fact that only
~2% of bowhead whales observed by Bureau of Ocean Energy Management's
(BOEM) aerial surveys from 1979-2007 occurred in areas of water depth
>1,000 m (3,281 ft) (MMS 2010), and on average ~97% of bowheads have
passed through the eastern U.S. Beaufort Sea by October 15 (Miller et
al. 2002). The survey would then progress to shallower waters in the
eastern survey area before moving to the western survey area in late
October or early November 2012. NMFS has conducted thorough analysis on
potential disturbances of bowhead whales and other marine mammals in
the entire Beaufort and Chukchi Seas for the period of ION's in-ice
seismic survey and reached a negligible determination. Finally, at this
point it is clear that the delay of ION's in-ice seismic survey into
mid- to late October would further reduce impacts to marine mammals in
the action area.
Comment 24: The Commission requests that NMFS require ION to (1)
record, analyze, and report (within five days of collecting the data)
the results of measurements of vessel sounds, including the icebreaking
vessel and (2) adjust the size of the 120-dB re 1 [micro]Pa harassment
zone and revise the estimated number of animals expected to be taken by
Level B harassment for all icebreaking activities, as necessary.
Response: NMFS worked with ION on its sound source verification
(SSV) measures when it first submitted its IHA application in 2010 and
has continued to do so for the 2012 application. Due to the unique
situation of the in-ice seismic survey, the traditional method of SSV
test using bottom mounted hydrophone would not work. NMFS and ION have
agreed to use the SSV measurements that ION collected in the ice-free
Canadian Beaufort Sea, coupling with the in-situ sound velocity profile
measurements in the seismic survey areas in the Beaufort and Chukchi
Seas, to model the exclusion zones (180 and 190 dB re 1 [micro]Pa for
cetaceans and pinnipeds, respectively) and behavioral harassment zones
(160 and 120 dB re 1 [micro]Pa for seismic airgun array and icebreaking
activity, respectively). However, after NMFS published its proposed
IHA, ION informed NMFS that direct SSV measurements of airgun would be
possible in the U.S. Beaufort Sea based on ice condition prediction.
Therefore, ION will be conducting traditional SSV tests on its airgun
array prior to conducting seismic surveys and submit the results within
five days of collecting the data. ION will also adjust the size of the
take zones based on the SSV tests. Nevertheless, NMFS does not believe
direct SSV test in open water would be a good indicator for measuring
icebreaking noise, since this would be an underestimate of noise
produced during actual icebreaking activities. Therefore, for
icebreaking activities, ION would use its seismic survey streamer to
measure its noise during actual icebreaking, which is described in the
Federal Register notice for the proposed IHA (77 FR 49922; August 17,
2012). In addition, overwintering buoys deployed by ION and its partner
would also provide better estimates of noise levels from icebreaking
activities. However, these are no SSV measurements as these
measurements could not be carried out under controlled test setting.
Nevertheless, NMFS believes that the 160-dB re 1 [micro]Pa harassment
zone from the seismic airgun array would surpass the 120-dB re 1
[micro]Pa harassment zone from icebreaking activity based on acoustic
modeling. Therefore, the 160-dB re 1 [micro]Pa received level from the
airgun array would determine the numbers of marine mammals being taken.
Comment 25: The NSB is concerned that ION's in-ice seismic survey
would
[[Page 65070]]
be conducted during the time when visibility would be poor most of the
time. The Commission and NSB request that NMFS require ION to use
active acoustic monitoring, whenever practicable, to supplement visual
monitoring during the implementation of its mitigation measures for all
activities that generate sound. The NSB further recommends ION deploy
their own acoustic recorders and collect the acoustic data.
Response: As noted, NMFS' analyses on the potential impacts on
marine mammals likely overestimates the number of animals taken and our
analysis of the nature, context, and severity of those takes allowed to
conclude that the taking will have a negligible impact on affected
species or stocks. Further, NMFS has concluded that acoustic monitoring
for ION's in-ice seismic survey is not necessary or practicable. In the
Environmental Assessment prepared by NMFS, NMFS considered requiring
ION to employ a near real-time passive acoustic monitoring (PAM) and
active acoustic monitoring (AAM) program. These measures would
supplement visual observation that is already required for ION.
However, we determined these technologies should not be utilized in
this particular instance because (1) the technologies are still being
developed and thus, the efficacy of these measures for ION's survey
would be questionable; and (2) the use of PAM, in particular, would
require an additional icebreaker to serve as a PAM platform. After
consulting with ION, we determined that a second icebreaker would not
be practicable from an operational and economic perspective and could
also result in additional environmental impacts such as additional
noise being introduced into the water and disturbed habitat by
additional icebreaking activities. Although NMFS has required the use
of PAM in past IHAs (e.g., Houser et al. 2008; McPherson et al. 2012)
and it has shown to be able to detect marine mammals beyond visual
observation, as explained previously, we do not believe PAM is an
appropriate mitigation tool for ION's project.
Nevertheless, NMFS requires ION to work with other oil and gas
companies in the Arctic to deploy overwintering acoustic sensors to
assess the impacts of its in-ice seismic survey and provide a baseline
of the acoustic environment and marine mammal distribution during the
winter season.
Comment 26: The Commission requests that NMFS specify reduced
vessel speeds of 9 knots or less when in transit and 5 knots or less
when weather conditions or darkness reduce visibility.
Response: NMFS does not agree with the Commission's recommendation
of specifying vessel speeds of 9 knots or less when in transit and 5
knots or less when weather conditions or darkness reduce visibility. As
NMFS discussed with ION, stipulating vessel speed during transit would
severely hamper its proposed seismic survey activity, and would not be
practicable. In any event, ION has indicated that its seismic vessel
and icebreaker would normally move at a speed of 9-12 knots during
transit and 4-5 knots during seismic survey.
NEPA and Miscellaneous Issues
Comment 27: Noting that NMFS is still working on the Arctic EIS,
AWL et al. and Oceana state that NEPA regulations makes clear that
agencies should not proceed with authorizations for individual projects
like the ION proposal until an ongoing programmatic EIS is complete.
Response: NMFS does not agree with AWL et al. and Oceana's
statement. While the Final EIS is still being developed, NMFS conducted
a thorough analysis of the affected environment and environmental
consequences from ION's in-ice seismic survey in the Beaufort and
Chukchi Seas in 2012 and prepared an EA specific to the seismic survey
program proposed to be conducted by ION. The analysis contained in that
EA warranted a finding of no significant impact.
The analysis contained in the Final EIS will apply more broadly to
multiple Arctic oil and gas operations over an extended period. NMFS'
issuance of the IHA to ION for the taking of several species of marine
mammals incidental to conducting its in-ice seismic survey in the
Beaufort and Chukchi Seas in 2012, as analyzed in the EA, is not
expected to significantly affect the quality of the human environment.
Additionally, the EA contained a full analysis of cumulative impacts.
Comment 28: PEW states that traditional knowledge needs to be
better incorporated into NMFS' analyses.
Response: NMFS agrees that traditional knowledge (TK) is generally
useful in understanding the potential environmental and subsistence
impacts from activities such as ION's in-ice seismic survey. In fact,
TK has been an important factor during NMFS analyses and review process
of ION's in-ice seismic survey project, especially for the
environmental analysis under the National Environmental Policy Act
(NMFS 2012b). For instance, part of the analysis on bowhead whale
westbound migration that does not depend on the Chukchi Sea ice lead
system is from TK as described in Huntington and Quakenbush (2009).
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 two cetacean species, beluga
(Delphinapterus leucas) and bowhead whales (Balaena mysticetus), and
two pinniped species, ringed (Phoca hispida) and bearded (Erignathus
barbatus) seals
Three additional cetacean species and two pinniped species: Harbor
porpoise (Phocoena phocoena), gray whale (Eschrichtius robustus), and
minke whale (Balaenoptera acutorostrata); and spotted (P. largha) and
ribbon seals (Histriophoca fasciata) could also occur in the project
area.
The bowhead whale is listed as ``endangered'' 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 listed as
endangered or proposed for listing under the ESA; however, none of
those stocks or populations occur in the proposed activity area. The
ESA-listed western North Pacific gray whale population occurs in the
West Pacific, and the ESA-listed Cook Inlet beluga population resides
in Cook Inlet, Alaska. The southern distinct population segment of
spotted seal that is listed under the ESA is found in Liaodong Bay,
China, and Peter the Great Bay, Russia. Additionally, the ribbon seal
is considered a ``species of concern'', meaning that NMFS has some
concerns regarding status and threats to this species, but for which
insufficient information is available to indicate a need to list the
species under the ESA. Bearded and ringed seals are ``candidate
species'' under the ESA, meaning they are currently being considered
for listing.
ION's application contains information on the status, distribution,
seasonal distribution, and abundance of each of the species under NMFS'
jurisdiction mentioned. 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 2011 SAR is
available at: http://www.nmfs.noaa.gov/pr/pdfs/sars/ak2011.pdf.
[[Page 65071]]
Potential Effects of the Specified Activity on Marine Mammals
Operating active acoustic sources such as airgun arrays and
icebreaking activities have the potential for adverse effects on marine
mammals.
Potential Effects of Airgun Sounds on Marine Mammals
The effects of sounds from airgun pulses might include one or more
of the following: Tolerance, masking of natural sounds, behavioral
disturbance, and temporary or permanent hearing impairment or non-
auditory effects (Richardson et al. 1995). As outlined in previous NMFS
documents, the effects of noise on marine mammals are highly variable.
The Notice of Proposed IHA (77 FR 49922; August 17, 2012) included a
discussion of the effects of airguns on marine mammals, which is not
repeated here. That discussion did not take into consideration the
monitoring and mitigation measures proposed by ION and those that will
be required by NMFS. No instances of serious injury or mortality are
expected as a result of ION's activities given the strong likelihood
that marine mammals (especially migrating bowheads) would avoid the
approaching airguns (or vessel) before being exposed to levels high
enough for them to be seriously injured or killed.
Potential Effects From Icebreaking on Marine Mammals
Icebreaking would be carried out for the ION's proposed in-ice
seismic survey activities in the Beaufort and Chukchi Seas. Acoustic
source modeling and propagation of the icebreaker were provided in the
Notice of Proposed IHA (77 FR 49922; August 17, 2012). The source
levels of the icebreaker are much lower than those of the airguns.
Although they are non-impulse sounds and are treated differently from
airgun pulses when the Level B behavioral harassment is considered, the
120 dB re 1 [micro]Pa radii from icebreaking activities are still
smaller than the 160 dB re 1 [micro]Pa radii. Therefore, the zone of
influence from the airgun arrays essentially covers the area that would
be ensonified by icebreaking activities during the survey, except for
vessel transiting. The potential effects of icebreaking to marine
mammals are discussed in the Federal Register notice for the proposed
IHA (77 FR 49922; August 17, 2012) and are not repeated here.
Anticipated Effects on Habitat
The primary potential impacts to marine mammals and other marine
species are associated with elevated sound levels produced by airguns
and other active acoustic sources, noise generated from icebreaking,
and breaking of ice during the seismic survey. However, other potential
impacts to the surrounding habitat from physical disturbance are also
possible. Major potential anticipated effects on habitat from ION's
proposed in-ice seismic survey include impacts on prey species (fish
and other marine species that serve as marine mammal food) and physical
environment (the destroy of ice layers) and are discussed in detail in
the Federal Register notice for the proposed IHA (77 FR 49922; August
17, 2012) and are not repeated here.
Potential Impacts on Availability of Affected Species or Stock for
Taking for 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.''
Seismic surveys and associated icebreaking operations have the
potential to impact marine mammals hunted by Native Alaskans. In the
case of cetaceans, the most common reaction to anthropogenic sounds (as
noted previously in this document) is avoidance of the ensonified area.
In the case of bowhead whales, this often means that the animals could
divert from their normal migratory path by up to several kilometers.
Additionally, general vessel presence in the vicinity of traditional
hunting areas could negatively impact a hunt.
In the case of subsistence hunts for bowhead whales in the Beaufort
and Chukchi Seas, there could be an adverse impact on the hunt if the
whales were deflected seaward (further from shore) in traditional
hunting areas. The impact would be that whaling crews would have to
travel greater distances to intercept westward migrating whales,
thereby creating a safety hazard for whaling crews and/or limiting
chances of successfully striking and landing bowheads. Native knowledge
indicates that bowhead whales become increasingly ``skittish'' in the
presence of seismic noise. Whales are more wary around the hunters and
tend to expose a much smaller portion of their back when surfacing
(which makes harvesting more difficult). Additionally, natives report
that bowheads exhibit angry behaviors in the presence of seismic, such
as tail-slapping, which translate to danger for nearby subsistence
harvesters.
However, due to its proposed time and location, ION's proposed in-
ice seismic survey in the Beaufort and Chukchi Seas would be unlikely
to result in the aforementioned impacts. As discussed in detail in the
Federal Register for the proposed IHA (77 FR 49922; August 17, 2012),
the only potential impacts on subsistence use of marine mammals from
ION's proposed icebreaking seismic survey during October--December
period are the fall bowhead hunt and ringed seal harvest. Nevertheless,
the proposed seismic survey is expected to occur in waters far offshore
from the regular seal hunting areas, and ION indicates it would elect
to operate at the eastern end of the survey area until fall whaling in
the Beaufort Sea near Barrow is finished, thus reducing the likelihood
of interfering with subsistence use of marine mammals in the vicinity
of the project area.
Finally, ION has signed a Conflict Avoidance Agreement (CAA), and
prepared a Plan of Cooperation (POC) under 50 CFR 216.104 to address
potential impacts on subsistence hunting activities. The CAA identifies
those measures will be taken to minimize adverse impacts of the planned
activities on subsistence harvesting. ION met with the AEWC and
communities' Whaling Captains' Associations as part of the CAA
development, and established avoidance guidelines and other mitigation
measures to be followed where the activities may have an impact on
subsistence.
Mitigation Measures
Any incidental take authorization (ITA) under Section 101(a)(5)(D)
of the MMPA, must prescribe where applicable, the permissible methods
of taking pursuant to such activity, and other means of effecting the
least practicable impact on such species or stock and its habitat,
paying particular attention to rookeries, mating grounds, and areas of
similar significance, and on the availability of such species or stock
for taking for certain subsistence uses.
For ION's in-ice seismic survey in the Beaufort and Chukchi Seas,
NMFS is requiring ION to implement the following mitigation measures to
minimize the potential impacts to marine mammals in the project
vicinity
[[Page 65072]]
as a result of the marine seismic survey activities.
The mitigation measures are divided into the following major
groups: (1) Establishing exclusion and disturbance zones, (2) Vessel
speed or course alteration, (3) Ramp up procedures (4) Power down
procedures, and (5) Shutdown procedures. 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) Exclusion Zones
Under current NMFS guidelines, ``exclusion zones'' for marine
mammals around industrial sound sources are customarily defined as the
distances within which received sound levels are >=180 dB re 1 [mu]Pa
(rms) for cetaceans and >=190 dB re 1 [mu]Pa (rms) for pinnipeds. These
criteria are based on an assumption that sound energy at lower received
levels will not injure these animals or impair their hearing abilities
but that higher received 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 zone (Richardson et al., 1995).
Received sound levels were modeled for the full 26 airgun, 4,450
in\3\ array in relation to distance and direction from the source
(Zykov et al., 2010). Based on the model results, Table 1 in this
document shows the distances from the airguns where ION predicts that
received sound levels will drop below 190, 180, and 160 dB re 1 [mu]Pa
(rms). A single 70-in\3\ airgun would be used during turns or if a
power down of the full array is necessary due to the presence of a
marine mammal within or about to enter the applicable exclusion zone of
the full airgun array. To model the source level of the 70-in\3\
airgun, ION used the measurements of a 30-in\3\ airgun. Underwater
sound propagation of a 30-in\3\ airgun was measured in <100 m (328 ft)
of water near Harrison Bay in 2007, and results were reported in Funk
et al. (2008). The constant term of the resulting equation was
increased by 2.45 dB based on the difference between the volume of the
two airguns [2.45 = 20Log(70/30)-(\1/3\)]. The 190 and 180 dB (rms)
distances for the 70-in\3\ airgun from the adjusted equation, 19 m (62
ft) and 86 m (282 ft) respectively, would be used as the exclusion
zones around the single 70 in\3\ airgun in all water depths until
results from field measurements are available.
An acoustics contractor would perform the direct measurements of
the received levels of underwater sound versus distance and direction
from the energy source arrays using calibrated hydrophones (see below
``Sound Source Verification'' in the ``Monitoring and Reporting
Measures'' section). The acoustic data would be analyzed as quickly and
as reasonably practicable in the field and used to verify (and if
necessary adjust) the size of the exclusion zones. The field report
will be made available to NMFS and the Protected Species Observers
(PSOs) within 120 hrs of completing the measurements. The mitigation
measures to be implemented at the 190 and 180 dB (rms) sound levels
would include power downs and shut downs as described below.
Table 1--Marine Mammal Exclusion Zones From the 26 Airgun, 4,450-in\3\ Array, for Specific Categories Based on
the Water Depth
----------------------------------------------------------------------------------------------------------------
Exclusion and disturbance zones (meters)
-----------------------------------------------------
rms (dB re. 1 [mu]Pa) Depth less than Depth 100 m- Depth more than
100 m 1,000 m 1,000 m
----------------------------------------------------------------------------------------------------------------
190....................................................... 600 180 180
180....................................................... 2,850 660 580
160....................................................... 27,800 42,200 31,600
----------------------------------------------------------------------------------------------------------------
(2) Speed or Course Alteration
If a marine mammal (in water) is detected outside the exclusion
zone and, based on its position and the relative motion, is likely to
enter the exclusion zone, the vessel's speed and/or direct course shall
be changed in a manner that also minimizes the effect on the planned
objectives when such a maneuver is safe.
Another measure proposes to avoid concentrations or groups of
whales by all vessels in transit under the direction of ION. Operators
of vessels should, at all times, conduct their activities at the
maximum distance possible from such concentrations of whales.
All vessels during transit shall be operated at speeds necessary to
ensure no physical contact with whales occurs. If any barge or transit
vessel approaches within 1.6 km (1 mi) of observed bowhead whales, the
vessel operator shall take reasonable precautions to avoid potential
interaction with the bowhead whales by taking one or more of the
following actions, as appropriate:
(A) Reducing vessel speed to less than 5 knots within 300 yards
(900 feet or 274 m) of the whale(s);
(B) Steering around the whale(s) if possible;
(C) Operating the vessel(s) in such a way as to avoid separating
members of a group of whales from other members of the group;
(D) Operating the vessel(s) to avoid causing a whale to make
multiple changes in direction; and
(E) Checking the waters immediately adjacent to the vessel(s) to
ensure that no whales will be injured when the propellers are engaged.
When weather conditions require, such as when visibility drops,
adjust vessel speed accordingly to avoid the likelihood of injury to
whales.
In the event that any aircraft (such as helicopters) are used to
support the planned survey, the proposed mitigation measures below
would apply:
(A) Under no circumstances, other than an emergency, shall aircraft
be operated at an altitude lower than 1,000 feet above sea level (ASL)
when within 0.3 mile (0.5 km) of groups of whales.
(B) Helicopters shall not hover or circle above or within 0.3 mile
(0.5 km) of groups of whales.
(3) Ramp Ups
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 is to ``warn'' marine mammals in the vicinity of the airguns
and to provide the time for them to leave the area and thus avoid any
potential injury or impairment of their hearing abilities.
During the proposed seismic 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 or when no airguns have been
[[Page 65073]]
firing) will begin by firing a single airgun in the array. A full ramp
up, following a cold start, can be applied if the exclusion zone has
been free of marine mammals for a consecutive 30-minute period. The
entire exclusion zone must have been visible during these 30 minutes.
If the entire exclusion zone is not visible, then ramp up from a cold
start cannot begin.
Ramp up procedures from a cold start shall be delayed if a marine
mammal is sighted within the exclusion zone during the 30-minute period
prior to the ramp up. The delay shall last until the marine mammal(s)
has been observed to leave the exclusion zone or until the animal(s) is
not sighted for at least 15 or 30 minutes. The 15 minutes applies to
small odontocetes and pinnipeds, while a 30 minute observation period
applies to baleen whales and large toothed whales.
A ramp up, following a shutdown, can be initiated if the marine
mammal(s) for which the shutdown occurred has been observed to leave
the exclusion zone or until the animal(s) is not sighted for at least
15 minutes (small odontocetes and pinnipeds) or 30 minutes (baleen
whales and large toothed whales).
If, for any reason, electrical power to the airgun array has been
discontinued for a period of 10 minutes or more, ramp-up procedures
shall be implemented. Only if the PSO watch has been suspended, a 30-
minute clearance of the exclusion zone is required prior to commencing
ramp-up. Discontinuation of airgun activity for less than 10 minutes
does not require a ramp-up.
The seismic operator and PSOs shall maintain records of the times
when ramp-ups start and when the airgun arrays reach full power.
During turns and transit between seismic transects, the 70 in\3\
mitigation gun will remain operational. The ramp up procedure will
still be followed when increasing the source levels from one airgun to
the full array. PSOs will be on duty whenever the airguns are firing
during daylight and during the 30 minute periods prior to full ramp
ups. Daylight will occur for ~11 hours/day at the start of the survey
in mid-October diminishing to ~3 hours/day in mid-November.
(4) Power Down Procedures
A power down involves decreasing the number of airguns in use such
that the radii of the 190 and 180 dB re 1 [mu]Pa (rms) zones are
decreased to the extent that observed marine mammals are not in the
applicable exclusion zone. A power down may also occur when the vessel
is moving from one seismic line to another. During a power down, only
one airgun is operated. The continued operation of one airgun is
intended to (a) alert marine mammals to the presence of the seismic
vessel in the area, and (b) retain the option of initiating a ramp up
to full array under poor visibility conditions. In contrast, a shutdown
is when all airgun activity is suspended (see next section).
If a marine mammal is detected outside the exclusion zone but is
likely to enter the exclusion zone, and if the vessel's speed and/or
course cannot be changed to avoid having the mammal enter the exclusion
zone, the airguns may (as an alternative to a complete shutdown) be
powered down before the mammal is within the exclusion zone. Likewise,
if a mammal is already within the exclusion zone when first detected,
the airguns will be powered down immediately if this is a reasonable
alternative to a complete shutdown. During a power down of the array,
the number of guns operating will be reduced to a single 70 in\3\
airgun. The pre-season estimates of the 190 dB re 1 [mu]Pa (rms) and
180 dB re 1 [mu]Pa (rms) exclusion zones around the power down source
are 19 m (62 ft) and 86 m (282 ft), respectively. The 70 in\3\ airgun
power down source will be measured during acoustic sound source
measurements conducted at the start of seismic operations. If a marine
mammal is detected within or near the applicable exclusion zone around
the single 70 in\3\ airgun, it too will be deactivated, resulting in a
complete shutdown (see next subsection).
Marine mammals hauled out on ice may enter the water when
approached closely by a vessel. If a marine mammal on ice is detected
by PSOs within the exclusion zones, it will be watched carefully in
case it enters the water. In the event the animal does enter the water
and is within an applicable exclusion zone of the airguns during
seismic operations, a power down or shut-down will immediately be
initiated. If the animal does not enter the water, it will not be
exposed to sounds at received levels for which mitigation is required;
therefore, no mitigation measures will be implemented.
Following a power down, operation of the full airgun array will not
resume until the marine mammal has cleared the exclusion zone. The
animal will be considered to have cleared the exclusion zone if it:
Is visually observed to have left the exclusion zone, or
Has not been seen within the zone for 15 min in the case
of pinnipeds (excluding walruses) or small odontocetes, or
Has not been seen within the zone for 30 min in the case
of mysticetes or large odontocetes.
(5) Shutdown Procedures
The operating airgun(s) will be shut down completely if a marine
mammal approaches or enters the then-applicable exclusion zone and a
power down is not practical or adequate to reduce exposure to less than
190 or 180 dB re 1 [mu]Pa (rms). The operating airgun(s) will also be
shut down completely if a marine mammal approaches or enters the
estimated exclusion zone around the reduced source (one 70 in\3\
airgun) that will be used during a power down.
Airgun activity will not resume until the marine mammal has cleared
the exclusion zone. The animal will be considered to have cleared the
exclusion zone if it is visually observed to have left the exclusion
zone, or if it has not been seen within the zone for 15 min (pinnipeds
and small odontocetes) or 30 min (mysticetes and large odontocetes).
Ramp up procedures will be followed during resumption of full seismic
operations after a shutdown of the airgun array.
In addition, a single airgun (also referred to as the ``mitigation
gun'' in past IHAs) shall not be kept firing for long periods of time
during darkness or other periods of poor visibility when seismic
surveys are not ongoing, with the exception of turns when starting a
new trackline, or short transits or maintenance with a duration of less
than one hour.
Finally, if a pinniped is sighted hauled out on ice within the
underwater exclusion zone (received level 190 dB re 1 [mu]Pa (rms)), it
will be watched carefully by the PSOs. Even though the pinniped may not
be exposed to in-air noise levels that could be considered a take, the
presence of the seismic vessel could prompt the animal to slip into the
water, and thus be exposed to a high intensity sound field as a result.
Therefore, the airgun should be powered down or shutdown immediately if
thepinniped enters the water.
Mitigation Measures for Subsistence Activities
(1) Subsistence Mitigation Measures
Since ION's proposed October--December in-ice seismic survey in the
Beaufort and Chukchi Seas is unlikely to result in adverse impacts to
subsistence users due to its proposed time and location, no specific
mitigation measures are proposed other than those general mitigation
measures discussed above.
[[Page 65074]]
(2) Plan of Cooperation (POC) and Conflict Avoidance Agreement (CAA)
Regulations at 50 CFR 216.104(a)(12) require IHA applicants for
activities that take place in Arctic waters to provide a 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.
ION has signed a Conflict Avoidance Agreement (CAA) with the Alaska
Eskimo Whaling Commission (AEWC) and communities' Whaling Captains'
Associations for the proposed 2012 in-ice seismic survey. The main
purpose of the CAA is to provide (1) equipment and procedures for
communications between subsistence participants and industry
participants; (2) avoidance guidelines and other mitigation measures to
be followed by the industry participants working in or transiting in
the vicinity of active subsistence hunters, in areas where subsistence
hunters anticipate hunting, or in areas that are in sufficient
proximity to areas expected to be used for subsistence hunting that the
planned activities could potentially adversely affect the subsistence
bowhead whale hunt through effects on bowhead whales; and (3) measures
to be taken in the event of an emergency occurring during the term of
the CAA.
The CAA states that all vessels (operated by ION) shall report to
the appropriate Communication Center (Com-Center) at least once every
six hours commencing with a call at approximately 06:00 hours. The
appropriate Com-Center shall be notified if there is any significant
change in plans, such as an unannounced start-up of operations or
significant deviations from announced course, and such Com-Center shall
notify all whalers of such changes.
The CAA further states that each Com-Center shall have an Inupiat
operator (``Com-Center operator'') on duty 24 hours per day during the
2012 subsistence bowhead whale hunt.
In addition, ION has developed a ``Plan of Cooperation'' (POC) for
the 2012 seismic survey in the Beaufort and Chukchi Seas in
consultation with representatives of Barrow, Nuiqsut, Kaktovik, and
Wainwright and subsistence users within these communities. NMFS
received the final POC on August 13, 2012. The final POC is posted on
NMFS Web site at http://www.nmfs.noaa.gov/pr/permits/incidental.htm#applications.
Mitigation Conclusions
NMFS has carefully evaluated these 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;
The proven or likely efficacy of the specific measure to
minimize adverse impacts as planned; 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 and proposed by the
independent peer review panel, NMFS has determined that the proposed
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
Any ITA issued under Section 101(a)(5)(D) of the MMPA is required
to prescribe, where applicable, ``requirements pertaining to the
monitoring and reporting of such taking.'' The MMPA implementing
regulations at 50 CFR 216.104(a)(13) state 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.
(1) Protected Species Observers (PSOs)
Vessel-based monitoring for marine mammals shall be performed by
trained PSOs throughout the period of survey activities, supplemented
by the officers on duty, to comply with expected provisions in the IHA.
The observers shall monitor the occurrence and behavior of marine
mammals near the survey vessels during all daylight periods. PSO duties
include watching for and identifying marine mammals; recording their
numbers, distances, and reactions to the survey operations; and
documenting ``take by harassment'' as defined by NMFS.
A. Number of Observers
A sufficient number of PSOs shall 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.
An experienced field crew leader shall supervise the PSO team
onboard the survey vessels. ION's proposed survey will occur in
October-December when the number of hours of daylight is significantly
reduced, and thus will require fewer PSOs to be aboard the survey
vessel than required for surveys conducted during the open water season
with nearly 24 hrs of daylight. PSOs aboard the icebreaker operating
0.5-1 km (0.31-0.62 mi) ahead of the survey vessel will provide early
detection of marine mammals along the survey track. Three PSOs will be
stationed aboard the icebreaker Polar Prince to take advantage of this
forward operating platform and provide advance notice of marine mammals
to the PSO on the survey vessel. Three PSOs will be stationed aboard
the survey vessel Geo Arctic to monitor the exclusion zones centered on
the airguns and to request mitigation actions when necessary.
B. Observer Qualifications and Training
Crew leaders and most other biologists serving as observers shall
be individuals with recent experience as observers during one or more
seismic monitoring projects in Alaska, the Canadian Beaufort Sea, or
other offshore areas.
Biologist-observers shall have previous marine mammal observation
experience, and field crew leaders will be highly experienced with
previous vessel-based marine mammal monitoring and mitigation projects.
R[eacute]sum[eacute]s for all individuals shall be provided to NMFS for
review and acceptance of their qualifications. Inupiat observers will
be experienced in the region, familiar with the marine mammals of the
area, and complete an approved observer training course designed to
familiarize individuals with monitoring and data collection procedures.
A PSO handbook, adapted for the specifics of the planned survey
program, will be prepared and distributed beforehand to all PSOs.
Biologist-observers and Inupiat observers shall also complete a two
or three-day training and refresher session together on marine mammal
monitoring, to be conducted shortly before the anticipated start of the
seismic survey. When possible, experienced observers shall be paired
with inexperienced observers. The training session(s) shall be
conducted by qualified marine
[[Page 65075]]
mammalogists with extensive crew-leader experience during previous
vessel-based seismic monitoring programs.
Primary objectives of the training include:
Review of the marine mammal monitoring plan for this
project, including any amendments specified by NMFS in the IHA;
Review of marine mammal sighting, identification, and
distance estimation methods using visual aids;
Review of operation of specialized equipment (reticle
binoculars, night vision devices (NVDs), and GPS system);
Review of, and classroom practice with, data recording and
data entry systems, including procedures for recording data on marine
mammal sightings, monitoring operations, environmental conditions, and
entry error control. These procedures will be implemented through use
of a customized computer database and laptop computers;
Review of the specific tasks of the Inupiat Communicator;
and
Exam to ensure all observers can correctly identify marine
mammals and record sightings.
C. PSO Handbook
A PSOs' Handbook will be prepared for ION's monitoring program.
Handbooks contain maps, illustrations, and photographs, as well as
text, and are intended to provide guidance and reference information to
trained individuals who will participate as PSOs. The following topics
will be covered in the PSO Handbook for the ION project:
Summary overview descriptions of the project, marine
mammals and underwater noise, the marine mammal monitoring program
(vessel-based, aerial, acoustic measurements), the NMFS' IHA (if
issued) and other regulations/permits/agencies, the Marine Mammal
Protection Act;
Monitoring and mitigation objectives and procedures,
initial exclusion zones;
Responsibilities of staff and crew regarding the marine
mammal monitoring plan;
Instructions for ship crew regarding the marine mammal
monitoring plan;
Data recording procedures: codes and coding instructions,
common coding mistakes, electronic database; navigational, marine
physical, field data sheet;
List of species that might be encountered: identification
cues, natural history information;
Use of specialized field equipment (reticle binoculars,
NVDs, forward-looking infrared (FLIR) system);
Reticle binocular distance scale;
Table of wind speed, Beaufort wind force, and sea state
codes;
Data storage and backup procedures;
Safety precautions while onboard;
Crew and/or personnel discord; conflict resolution among
PSOs and crew;
Drug and alcohol policy and testing;
Scheduling of cruises and watches;
Communication availability and procedures;
List of field gear that will be provided;
Suggested list of personal items to pack;
Suggested literature, or literature cited; and
Copies of the NMFS IHA and USFWS LOA.
(2) Monitoring Methodology
A. General Monitoring Methodology
The observer(s) will watch for marine mammals from the best
available vantage point on the survey vessels, typically the bridge.
The observer(s) will scan systematically with the unaided eye and 7 x
50 reticle binoculars, supplemented during good visibility conditions
with 20 x 60 image-stabilized Zeiss Binoculars or Fujinon 25 x 150
``Big-eye'' binoculars, a thermal imaging (FLIR) camera, and night-
vision equipment when needed (see below). Personnel on the bridge shall
assist the marine mammal observer(s) in watching for marine mammals.
Information to be recorded by observers shall include the same
types of information that were recorded during recent monitoring
programs associated with Industry activity in the Arctic (e.g., Ireland
et al., 2009). When a mammal sighting is made, the following
information about the sighting shall be recorded:
Species, group size, age/size/sex categories (if
determinable), behavior when first sighted and after initial sighting,
heading (if determinable), bearing and distance from observer, apparent
reaction to activities (e.g., none, avoidance, approach, etc.), closest
point of approach, and pace;
Additional details for any unidentified marine mammal or
unknown observed;
Time, location, speed, and activity of the vessel, sea
state, ice cover, visibility, and sun glare; and
The positions of other vessel(s) in the vicinity of the
observer location.
The ship's position, speed of the vessel, water depth, sea state,
ice cover, visibility, airgun status (ramp up, mitigation gun, or full
array), and sun glare shall also be recorded at the start and end of
each observation watch, every 30 minutes during a watch, and whenever
there is a change in any of those variables.
Distances to nearby marine mammals will be estimated with
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. However, previous
experience has shown that a Class 1 eye-safe device was not able to
measure distances to seals more than about 70 m (230 ft) away. The
device was very useful in improving the distance estimation abilities
of the observers at distances up to about 600 m (1,968 ft), the maximum
range at which the device could measure distances to highly reflective
objects such as other vessels. Humans observing objects of more-or-less
known size via a standard observation protocol, in this case from a
standard height above water, quickly become able to estimate distances
within about 20% when given immediate feedback about actual
distances during training.
When a marine mammal is seen within the exclusion zone applicable
to that species, the geophysical crew shall be notified immediately so
that mitigation measures required by the IHA (if issued) can be
implemented. It is expected that the airgun array will be shut down
within several seconds, often before the next shot would be fired, and
almost always before more than one additional shot is fired. The
protected species observer shall then maintain a watch to determine
when the mammal(s) appear to be outside the exclusion zone such that
airgun operations can resume.
ION will provide or arrange for the following specialized field
equipment for use by the onboard PSOs: 7 x 50 reticle binoculars, Big-
eye binoculars or high power image-stabilized binoculars, GPS unit,
laptop computers, night vision binoculars, digital still and possibly
digital video cameras in addition to the above mentioned FLIR camera
system (see below).
B. Monitoring at Night and in Poor Visibility
Night-vision equipment (Generation 3 binocular image intensifiers,
or equivalent units) will be available for use when/if needed. Past
experience with NVDs in the Beaufort Sea and elsewhere has indicated
that NVDs are
[[Page 65076]]
not nearly as effective as visual observation during daylight hours
(e.g., Harris et al., 1997, 1998; Moulton and Lawson, 2002). A FLIR
camera system mounted on a high point near the bow of the icebreaker
will also be available to assist with detecting the presence of seals
and polar bears on ice and, perhaps also in the water, ahead of the
airgun array. The FLIR system detects thermal contrasts and its ability
to sense these differences is not dependent on daylight.
Additional details regarding the monitoring protocol during NVD and
FLIR system use has been developed in order to collect data in a
standardized manner such that the effectiveness of the two devices can
be analyzed and compared.
B. (1) FLIR and NVD Monitoring
The infrared system is able to detect differences in the surface
temperature of objects making it potentially useful during both
daylight and darkness periods. NVDs, or light intensifiers, amplify low
levels of ambient light from moonlight or sky glow light in order to
provide an image to the user. Both technologies have the potential to
improve monitoring and mitigation efforts in darkness. However, they
remain relatively unproven in regards to their effectiveness under the
conditions and it the manner of use planned for this survey. The
protocols for FLIR and NVD use and data collection described below are
intended to collect the necessary data in order to evaluate the ability
of these technologies to aid in the detection of marine mammals from a
vessel.
All PSOs shall monitor for marine mammals according to the
procedures outlined in the PSO handbook.
One PSO shall be responsible for monitoring the FLIR
system (IR-PSO) during most darkness and twilight periods. The on-duty
IR-PSO shall monitor the IR display and alternate between the two
search methods described below. If a second PSO is on watch, they shall
scan the same area as the FLIR using the NVDs for comparison. The two
PSOs shall coordinate what area is currently being scanned.
The IR-PSO should rotate between the search methods (see
below) every 30 minutes in the following routine:
[cir] 00:00-00:30: Method I
[cir] 00:30-01:00: Method II, Port side
[cir] 01:00-01:30: Method I
[cir] 01:30-02:00: Method II, Starboard side
B. (2) FLIR Search Methods
The FLIR system consists of a camera that will be mounted on high
point in front of the vessel. The camera is connected to a joystick
control unit (JCU) and a display monitor that will be located on the
bridge of the vessel. The IR-PSO shall manually control the view that
is displayed by adjusting the pan (360[deg] continuous pan) and tilt
(+/-90[deg] tilt) settings using the JCU. The FLIR manufacturer has
indicated that they have tested the FLIR unit (model M626L) to -25
[deg]C (-13[emsp14][deg]F), but expect that it will operate at colder
temperatures. During the time of the proposed seismic survey, the
average minimum temperatures at Prudhoe Bay in October and November are
+10[emsp14][deg]F and -10[emsp14][deg]F, respectively. Colder
temperatures are certainly likely at times, but overall the
temperatures should generally be within the operational range of the
equipment.
As noted above, two different search methods shall be implemented
for FLIR monitoring and results from the two will be compared. The
first method involves a back-and-forth panning motion and the second
utilizes the FLIR unit focused on a fixed swath ahead and to one side
of the vessel track:
Method I: Set the horizontal tilt of the camera to an angle that
provides an adequate view out in front of the vessel and also provides
good resolution to potential targets (this will likely mean that the
lower portion of the view displayed on the monitor is of an area
relatively close to the vessel (<100 m [328 ft]) while the middle and
upper portions of the view are at greater distances (500-2,000 m
[1,640-6,562 ft]). Pan back and forth across the forward 180[deg] of
the vessels heading at a slow-scanning rate of approximately 1-2[deg]/
sec, as one would with binoculars. This method is intended to replicate
the type of observations conducted using binoculars and cover a
relatively wider swatch compared to Method II. It should produce
sightings data that can be analyzed using line-transect methodologies
to estimate marine mammal densities in the survey area.
Method II: Set the horizontal tilt of the camera to an angle that
provides an adequate view out in front of the vessel (similar or
identical to the above), and then set the camera at a fixed position
that creates a swath of view off the bow and to one side of the vessel
(see Figure 1 of ION's monitoring plan). This method essentially
establishes a fixed-strip width that is intended to produce sightings
data that can be analyzed using strip-transect methodologies to
estimate marine mammal densities.
B. (3) NVD Methods
The NVDs are goggles worn by the observer and are to be used in a
similar fashion as binoculars. When observing in conjunction with the
FLIR system, the objective will be to replicate the monitoring
methodology being employed by the FLIR system. Method I requires a full
180[deg] scan (or as large of a range as possible from the observer's
location) with the NVDs, and Method II requires a focused scan of the
~60[deg] swath being monitored by the FLIR system.
C. Field Data-Recording, Verification, Handling, and Security
The observers shall record their observations onto datasheets or
directly into handheld computers. During periods between watches and
periods when operations are suspended, those data shall be entered into
a laptop computer running a custom computer database. The accuracy of
the data entry shall be verified in the field by computerized validity
checks as the data are entered, and by subsequent manual checking of
the database printouts. These procedures will allow initial summaries
of data to be prepared during and shortly after the field season, and
shall facilitate transfer of the data to statistical, graphical or
other programs for further processing. Quality control of the data will
be facilitated by (1) the start-of-season training session, (2)
subsequent supervision by the onboard field crew leader, and (3)
ongoing data checks during the field season.
The data shall be backed up regularly onto CDs and/or USB disks,
and stored at separate locations on the vessel. If possible, data
sheets will be photocopied daily during the field season. Data shall be
secured further by having data sheets and backup data CDs carried back
to the Anchorage office during crew rotations.
In addition to routine PSO duties, observers shall use Traditional
Knowledge and Natural History datasheets to record observations that
are not captured by the sighting or effort data. Copies of these
records will be available to observers for reference if they wish to
prepare a statement about their observations. If prepared, this
statement would be included in the 90-day and final reports documenting
the monitoring work.
D. Effort and Sightings Data Collection Methods
Observation effort data shall be designed to capture the amount of
PSO effort itself, environmental conditions
[[Page 65077]]
that impact an observer's ability to detect marine mammals, and the
equipment and method of monitoring being employed. These data shall be
collected every 30 minutes or when an effort variable changes (e.g.,
change in the equipment or method being used to monitor, on/off-signing
PSO, etc.), and shall be linked to sightings data. Effort and sightings
data forms are the same forms used during other marine mammal
monitoring in the open water season, but additional fields have been
included to capture information specific to monitoring in darkness and
to more accurately describe the observation conditions. The additional
fields include the following.
Observation Method: FLIR, NVD, spotlight, eye (naked eye
or regular binoculars), or multiple methods. This data is collected
every 30 minutes with the Observer Effort form and with every sighting.
Cloud Cover: Percentage. This can impact lighting
conditions and reflectivity.
Precipitation Type: Fog, rain, snow, or none.
Precipitation Reduced Visibility: Confirms whether or not
visibility is reduced due to precipitation. This will be compared to
the visibility distance ( km) to determine when visibility is
reduced due to lighting conditions versus precipitation.
Daylight Amount: Daylight, twilight, dark. The addition of
the twilight field has been included to record observation periods
where the sun has set and observation distances may be reduced due to
lack of light.
Light Intensity: Recorded in footcandles (fc) using an
incident light meter. This procedure was added to quantify the
available light during twilight and darkness periods and may allow for
light-intensity bins to be used during analysis.
Analysis of the sightings data shall include comparisons of
nighttime (FLIR and NVD) sighting rates to daylight sighting rates.
FLIR and NVD analysis will be independent of each other and according
to method (I or II) used. Comparison of NVD and FLIR sighting rates
will allow for a comparison of marine mammal detection ability of the
two methods. However, results and analyses could be limited if
relatively few sightings are recorded during the survey.
(3) Acoustic Monitoring Plan
A. Sound Source Measurements
As described above, received sound levels were modeled for the full
26 airgun, 4,450 in\3\ array in relation to distance and direction from
the source (Zykov et al., 2010). These modeled distances will be used
as temporary exclusion zones until measurements of the airgun sound
source are conducted. The measurements shall be made at the beginning
of the field season, and the measured radii shall be used for the
remainder of the survey period. An acoustics contractor with experience
in the Arctic conducting similar measurements in recent years will use
their equipment to record and analyze the underwater sounds and write
the summary reports as described below.
The objectives of the sound source measurements planned for 2012 in
the Beaufort Sea will be (1) to measure the distances in potentially
ice covered waters in the broadside and endfire directions at which
broadband received levels reach 190, 180, 170, 160, and 120 dB re 1
[mu]Pa (rms) for the energy source array combinations that may be used
during the survey activities, and (2) measure the sounds produced by
the icebreaker and seismic vessel as they travel through sea ice.
Conducting the sound source and vessel measurements in ice-covered
waters using bottom founded recorders creates a risk of not being able
to retrieve the recorders and analyze the data until the following
year. If the acoustic recorders are not deployed or are unable to be
recovered because of too much sea ice, ION shall use measurements of
the same airgun source taken in the Canadian Beaufort Sea in 2010,
along with sound velocity measurements taken in the Alaskan Beaufort
Sea at the start of the 2012 survey to update the propagation model and
estimate new exclusion zones. These modeled results shall then be used
for mitigation purposes during the remainder of the survey.
The airgun configurations measured shall include at least the full
26 airgun array and the single 70 in\3\ mitigation airgun that will be
used during power downs. The measurements of airgun array sounds will
be made by an acoustics contractor at the beginning of the survey and
the distances to the various radii will be reported as soon as possible
after recovery of the equipment. The primary area of concern will be
the 190 and 180 dB re 1 [mu]Pa (rms) exclusion zones for pinnipeds and
cetaceans, respectively, and the 160 dB re 1 [mu]Pa Level B harassment
(for impulsive sources) radii. In addition to reporting the radii of
specific regulatory concern, nominal distances to other sound isopleths
down to 120 dB re 1 [mu]Pa (rms) shall be reported in increments of 10
dB.
Data shall be previewed in the field immediately after download
from the hydrophone instruments. An initial sound source analysis shall
be supplied to NMFS and the airgun operators within 120 hours of
completion of the measurements. The report shall indicate the distances
to sound levels based on fits of empirical transmission loss formulae
to data in the endfire and broadside directions. A more detailed report
will be issued to NMFS as part of the 90-day report following
completion of the acoustic program.
B. Seismic Hydrophone Streamer Recordings of Vessel Sounds
Although some measurements of icebreaking sounds have previously
been reported, acoustic data on vessels traveling through relatively
light ice conditions, as will be the case during the proposed survey,
are not available. In order to gather additional information on the
sounds produced by this type of icebreaking, ION proposes to use the
hydrophones in the seismic streamer on a routine basis throughout the
survey. Once every hour the airguns would not be fired at 2 consecutive
intervals (one seismic pulse interval is typically ~18 seconds, so
there will be ~54 seconds between seismic pulses at this time) and
instead a period of background sounds would be recorded, including the
sounds generated by the vessels. Over the course of the survey this
should generate as many as 750 records of vessel sounds traveling
through various ice conditions (from open water to 100% cover juvenile
first year ice or lighter multi-year ice). The acoustic data during
each sampling period from each hydrophone along the 9 km (5.6 mi)
streamer would be analyzed and used to estimate the propagation loss of
the vessel sounds. The acoustic data received from the hydrophone
streamer would be recorded at an effective bandwidth of 0-400 Hz. In
order to estimate sound energy over a larger range of frequencies
(broadband), results from previous measurements of icebreakers could be
generalized and added to the data collected during this project.
C. Over-Winter Acoustic Recorders
In order to collect additional data on the propagation of sounds
produced by icebreaking and seismic airguns in ice-covered waters, as
well as on vocalizing marine mammals, ION intends to collaborate with
other Industry operators to deploy acoustic recorders in the Alaskan
Beaufort Sea in fall 2012, to be retrieved during the 2013 open-water
season.
During winter 2011-2012, AURAL acoustic recorders were deployed at
or near each of the 5 acoustic array sites
[[Page 65078]]
established by Shell for monitoring the fall bowhead whale migration
through the Beaufort Sea, as well as one site near the shelf break in
the central Alaskan Beaufort Sea. These recorders will be retrieved in
July 2012, when Shell deploys Directional Autonomous Seafloor Acoustic
Recorders (DASARs) at 5 array locations. When the DASAR arrays are
retrieved in early October, ION intends to coordinate with Shell to re-
deploy the 6 AURAL recorders to the same locations used during the
2011-2012 winter. Redeploying the recorders in the same locations will
provide comparable data from a year with little to no offshore
industrial activity (2011) to a year with more offshore industrial
activity (2012). Acoustic data from the over-winter recorders will be
analyzed to address the following objectives:
Characterize the sounds and propagation distances produced
by ION's source vessel, icebreaker, and airguns on and to the edge of
the U.S. Beaufort Sea shelf,
Characterize ambient sounds and marine mammal calls during
October and November to assess the relative effect of ION's seismic
survey on the background conditions, and to characterize marine mammal
calling behavior, and
Characterize ambient sound and enumerate marine mammal
calls through acoustic sampling of the environment form December 2012
through July 2013, when little or no anthropogenic sounds are expected.
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 independent peer review panels to review ION's
mitigation and monitoring plan in its IHA applications submitted in
2010 and 2011 for taking marine mammals incidental to the proposed
seismic survey in the Beaufort and Chukchi Seas, during 2010 and 2011.
The panels met on March 25 and 26, 2010, and on March 9, 2011, and
provided their final report to NMFS on April 22, 2010 and on April 27,
2011, respectively. The full panel reports can be viewed at: http://www.nmfs.noaa.gov/pr/permits/incidental.htm#applications.
ION's proposed 2012 action is essentially the same as described in
its 2010 and 2011 IHA applications. NMFS worked with ION in 2010 and
2011 to address the peer review panels' recommendations on its 2010 and
2011 4MPs. Since ION's 2012 4MP addressed all issues raised during the
2010 and 2011 peer reviews and incorporated all of NMFS' requested
changes, NMFS decided it was not necessary to conduct a peer-review of
ION's 2012 4MP. All actions based on the 2010 and 2011 panel review are
discussed in the Federal Register notice for the proposed IHA (77 FR
49922; August 17, 2012), and is not repeated here.
Reporting Measures
(1) SSV Report
A report on the preliminary results of the acoustic verification
measurements, including as a minimum the measured 190-, 180-, 160-, and
120-dB re 1 [mu]Pa (rms) radii of the airgun arrays shall be submitted
within 120 hr after collection and analysis of those measurements at
the start of the field season. This report shall specify the distances
of the exclusion zones that were adopted for the marine survey
activities.
(2) Field Reports
Throughout the survey program, the observers shall prepare a report
each day or at such other intervals as the IHA may specify (if issued),
or ION may require summarizing the recent results of the monitoring
program. The field reports shall summarize the species and numbers of
marine mammals sighted. These reports shall be provided to NMFS and to
the survey operators.
(3) Technical Reports
The results of the vessel-based monitoring, including estimates of
``take by harassment'', shall be presented in the 90-day and final
technical reports. Reporting shall address the requirements established
by NMFS in the IHA. The technical report shall include:
(a) Summaries of monitoring effort: total hours, total distances,
and distribution of marine mammals through the study period accounting
for sea state and other factors affecting visibility and detectability
of marine mammals;
(b) Methods, results, and interpretation pertaining to all acoustic
characterization work and vessel-based monitoring;
(c) Analyses of the effects of various factors influencing
detectability of marine mammals including sea state, number of
observers, and fog/glare;
(d) Species composition, occurrence, and distribution of marine
mammal sightings including date, water depth, numbers, age/size/gender
categories, group sizes, and ice cover; and
(e) Analyses of the effects of survey operations:
Sighting rates of marine mammals during periods with and
without airgun activities (and other variables that could affect
detectability);
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''.
(4) Notification of Injured or Dead Marine Mammals
In addition to the reporting measures proposed by ION, NMFS will
require that ION notify NMFS' Office of Protected Resources and NMFS'
Stranding Network of sighting an injured or dead marine mammal in the
vicinity of marine survey operations. Depending on the circumstance of
the incident, ION shall take one of the following reporting protocols
when an injured or dead marine mammal is discovered in the vicinity of
the action area.
(a) In the unanticipated event that survey operations clearly cause
the take of a marine mammal in a manner prohibited by this
Authorization, such as an injury, serious injury or mortality (e.g.,
ship-strike, gear interaction, and/or entanglement), ION shall
immediately cease survey operations and immediately report the incident
to the Supervisor of Incidental Take Program, Permits and Conservation
Division, Office of Protected Resources, NMFS, and the Alaska Regional
Stranding Coordinators. The report must include the following
information:
(i) Time, date, and location (latitude/longitude) of the incident;
(ii) The name and type of vessel involved;
(iii) The vessel's speed during and leading up to the incident;
(iv) Description of the incident;
(v) Status of all sound source use in the 24 hours preceding the
incident;
(vi) Water depth;
(vii) Environmental conditions (e.g., wind speed and direction,
Beaufort sea state, cloud cover, and visibility);
[[Page 65079]]
(viii) Description of marine mammal observations in the 24 hours
preceding the incident;
(ix) Species identification or description of the animal(s)
involved;
(x) The fate of the animal(s); and
(xi) Photographs or video footage of the animal (if equipment is
available).
Activities shall not resume until NMFS is able to review the
circumstances of the prohibited take. NMFS shall work with ION to
determine what is necessary to minimize the likelihood of further
prohibited take and ensure MMPA compliance. ION may not resume their
activities until notified by NMFS via letter, email, or telephone.
(b) In the event that ION discovers an injured or dead marine
mammal, and the lead PSO determines that the cause of the injury or
death is unknown and the death is relatively recent (i.e., in less than
a moderate state of decomposition as described in the next paragraph),
ION will immediately report the incident to the Supervisor of the
Incidental Take Program, Permits and Conservation Division, Office of
Protected Resources, NMFS, and the Alaska Regional Stranding
Coordinators. The report must include the same information identified
above. Activities may continue while NMFS reviews the circumstances of
the incident. NMFS will work with ION to determine whether
modifications in the activities are appropriate.
(c) In the event that ION discovers an injured or dead marine
mammal, and the lead PSO determines that the injury or death is not
associated with or related to the activities authorized in the IHA (if
issued) (e.g., previously wounded animal, carcass with moderate to
advanced decomposition, or scavenger damage), ION shall report the
incident to the Supervisor of the Incidental Take Program, Permits and
Conservation Division, Office of Protected Resources, NMFS, and the
Alaska Regional Stranding Coordinators, within 24 hours of the
discovery. ION shall provide photographs or video footage (if
available) or other documentation of the stranded animal sighting to
NMFS and the Marine Mammal Stranding Network. ION can continue its
operations under such a case.
Estimated Take by Incidental Harassment
Except with respect to certain activities not pertinent here
(military readiness activities), 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]. For the most
part, only take by Level B behavioral harassment is anticipated as a
result of the proposed marine seismic survey. However, NMFS has
determined that Level A takes of a few individuals of marine mammals
could occur if the animals are unable to bedetected within the
exclusion zones for a prolonged period of time. Although NMFS believes
this is not likely, NMFS is proposing to authorize limited takes from
Level A harassment. Anticipated impacts to marine mammals are
associated with noise propagation from the seismic airgun(s) and the
icebreaking used during the seismic survey.
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 marine survey programs might include
one or more of the following: tolerance; 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.
NMFS uses the 160 dB and 120 dB re 1 [mu]Pa (rms) isopleths to
indicate the onset of Level B harassment by seismic airgun impulses and
by icebreaking noises, respectively. ION provided calculations for the
160-dB and 120-dB isopleths produced by these active acoustic sources
and then used those isopleths to estimate takes by harassment. NMFS
used the calculations to make preliminary findings under the MMPA. ION
provided a full description of the methodology used to estimate takes
by harassment in its IHA application (see ADDRESSES), which is also
described in the following sections.
ION has requested an authorization to take ten marine mammal
species by Level B harassment. These ten marine mammal species are:
beluga whale, harbor porpoise, bowhead whale, gray whale, humpback
whale, minke whale, bearded seal, ringed seal, spotted seal, and ribbon
seal. However, NMFS does not anticipate that humpback whales are likely
to be encountered during the season of ION's icebreaking seismic
survey. Therefore, NMFS determined that only nine of the species could
be affected and potentially taken by harassment. In addition, although
unlikely, NMFS determined that Level A takes of beluga whales, bowhead
whales, and ringed seals could also occur, as the proposed monitoring
and mitigation measures may not be 100% effective due to ice coverage
and extended periods of darkness. Regardless, our analysis has led us
to conclude that marine mammals will likely avoid the sound source
thereby minimizing the probability of exposure at a level that would
equate to Level A harassment.
Basis for Estimating ``Take by Harassment''
As stated previously, it is current NMFS practice to estimate take
by Level A harassment for received levels above 180 dB re 1 [mu]Pa
(rms) for cetaceans and 190 dB re 1 [mu]Pa (rms) for pinnipeds, and
take by Level B harassment for all marine mammals under NMFS
jurisdiction by impulse sounds at a received level above 160 dB re 1
[mu]Pa (rms) and by non-impulse sounds at a received level above 120 dB
re 1 [mu]Pa (rms). However, not all animals are equally affected by the
same received noise levels and, as described earlier, in most cases
marine mammals are not likely to be taken by Level A harassment
(injury) when exposed to received levels higher than 180 dB for a brief
period of time.
For behavioral harassment, marine mammals will likely not show
strong reactions (and in some cases any reaction) until sounds are much
stronger than 160 or 120 dB (for impulse and continuous sounds,
respectively). Southall et al. (2007) provide a severity scale for
ranking observed behavioral responses of both free-ranging marine
mammals and laboratory subjects to various types of anthropogenic sound
(see Table 4 in Southall et al. (2007)). Tables 7, 9, and 11 in
Southall et al. (2007) outline the numbers of low-frequency cetaceans,
mid-frequency cetaceans, and pinnipeds in water, respectively, reported
as having behavioral responses to multi-pulses in 10-dB received level
increments. These tables illustrate that the more severe reactions did
not occur until sounds were much higher than 160 dB re 1 [mu]Pa (rms).
Anticipated takes would include ``takes by harassment'' involving
temporary changes in behavior (Level B harassment) and TTS (Level B
harassment). NMFS does not consider injury (Level A harassment) to be
likely, however, due to the limited
[[Page 65080]]
effectiveness of monitoring and mitigation measures for animals
undetected under the ice and/or during the long periods of darkness, a
small amount of Level A harassment takes are also proposed to be
authorized. The sections below describe methods used to estimate ``take
by harassment'' and present estimates of the numbers of marine mammals
that might be affected during the proposed seismic survey in the U.S.
Beaufort Sea. The estimates are based on data obtained during marine
mammal surveys in the Beaufort Sea and on estimates of the sizes of the
areas where effects could potentially occur. In some cases, these
estimates were made from data collected from regions and habitats that
differed from the proposed project area. Adjustments to reported
population or density estimates were made on a case by case basis to
account for differences between the source data and the available
information on the distribution and abundance of the species in the
project area. This section provides estimates of the number of
potential ``exposures'' to impulsive sound levels >=160 dB re 1 [mu]Pa
(rms), non-pulse sound levels >=120 dB (rms) from icebreaking, and also
includes estimates of exposures to >=180 dB (rms) for cetaceans and
>=190 dB (rms) for seals.
Although several systematic surveys of marine mammals have been
conducted in the southern Beaufort Sea during spring and summer, few
data (systematic or otherwise) are available on the distribution and
numbers of marine mammals during the early winter period of this
survey, particularly in the northern Beaufort Sea. The main sources of
distributional and numerical data used in deriving the estimates are
described in the next subsection. There is some uncertainty about how
representative those data are and the assumptions used below to
estimate the potential ``take by harassment''. However, the approach
used here is accepted by NMFS as the best available at this time. That
is, we calculated the estimated take by multiplying the ensonified area
by the density of marine mammals. The following estimates are based on
a consideration of the number of marine mammals that might be disturbed
appreciably by ~7,250 line kilometers (4,505 line miles) of seismic
surveys across the Beaufort Sea and, to a lesser extent, the northern
Chukchi Sea.
Marine Mammal Density Estimates
This section describes the estimated densities of marine mammals
that may occur in the survey area. The area of water that may be
ensonified to various levels is described below. Although a marine
mammal may be exposed to icebreaking sounds >=120 dB (rms) or airgun
sounds >=160 dB (rms), this does not mean that every individual exposed
at these levels will actually exhibit a disruption of behavioral
patterns in response to the sound source. Not all animals react to
sounds at this low level, and many will not show strong reactions (and
in some cases any reaction) until sounds are much stronger. There are
several variables that determine whether or not an individual animal
will exhibit a response to the sound, such as the age of the animal,
previous exposure to this type of anthropogenic sound, habituation,
etc.
The survey has been designed to minimize interactions with marine
mammals by planning to conduct the work at times and in areas where the
relative density of marine mammals is expected to be quite low. The
survey will begin in offshore waters (>1,000 m [3,281 ft] deep) of the
eastern U.S. Beaufort Sea (east survey area) in mid-October. Weather
and ice permitting, the waters <1,000 m (3,281 ft) deep will not be
surveyed until mid-October and thereafter, in order to avoid migrating
bowhead whales. The western U.S. Beaufort Sea and north-eastern Chukchi
Sea (west survey area) is not expected to be surveyed until late
October through December.
Separate densities were calculated for habitats specific to
cetaceans and pinnipeds. For cetaceans, densities were estimated for
areas of water depth <200 m (656 ft), 200-1,000 m (656-3,281 ft), and
>1,000 m (3,281 ft), which approximately correspond to the continental
shelf, the continental slope, and the abyssal plain, respectively.
Separate densities of both cetacean and pinnipeds were also estimated
for the east and west survey areas within each water depth category.
However, pinniped densities in the west survey area and <200 m (656 ft)
water depth category were further sub-divided into <35 m (115 ft) and
35-200 m (115-656 ft) depth categories. This was done because the west
survey area is not expected to be surveyed until November-December, and
based on historic sea ice data (NOAA National Ice Center, available
online at www.natice.noaa.gov), it is expected that substantial amounts
of sea ice, including shorefast ice, will be present in the west survey
area at that time. Past studies have found that seal densities in ice-
covered areas of the Beaufort Sea are different where water depths are
<35 m (115 ft) and >35 m (Moulton et al., 2002; Frost et al., 2004);
therefore, densities were calculated separately for these water depths.
The north-eastern Chukchi Sea is composed of mostly continental shelf
waters between 30 m (98 ft) and 200 m (656 ft) in depth, so only a
single density estimate for each marine mammal species was used in that
area. Since most marine mammals will be continuing their southerly
migration in November and early December, the same density estimates
for continental shelf waters in the west survey area of the Beaufort
Sea were used in the Chukchi Sea. When the seismic survey area is on
the edge of the range of a species at this time of year, it is assumed
that the average density along the seismic trackline will be 10%
(0.10x) the density determined from available survey data within the
main range. Density estimates for the Chukchi Sea during the period of
November-December were taken from the west survey density estimates at
the appropriate depth.
Detectability bias, quantified in part by f(0), is associated with
diminishing sightability with increasing lateral distance from the
survey trackline. Availability bias, g(0), refers to the fact that
there is <100% probability of sighting an animal that is present along
the survey trackline. Some sources used below took account of one or
both of these correction factors in reporting densities. When these
factors had not been accounted for, the best available correction
factors from similar studies and/or species were applied to reported
results. Details regarding the application of correction factors are
provided below for each species.
(1) Cetaceans
Beluga Whales: Beluga density estimates were calculated based on
aerial survey data collected in October in the eastern Alaskan Beaufort
Sea by the NMML (as part of the Bowhead Whale Aerial Survey Project
(BWASP) program funded by BOEM) in 2007-2010. They reported 31
sightings of 66 individual whales during 1,597 km (992 mi) of on-
transect effort over waters 200-2,000 m (656-6,562 ft) deep. An f(0)
value of 2.326 was applied and it was calculated using beluga whale
sightings data collected in the Canadian Beaufort Sea (Innes et al.
2002). A g(0) value of 0.419 was used that represents a combination of
ga(0) = 0.55 (Innes et al., 2002) and gd(0) = 0.762 (Harwood et al.,
1996). The resulting density estimate (0.1169 individuals/km\2\; Table
2 in this document) was applied to areas of 200-1,000 m (656 -3,281
ft). There were 3 sightings of 4 individual beluga whales during 7,482
km (4,649 mi) of on-transect effort over waters 0-200 m (0-656 ft) deep
during this same time
[[Page 65081]]
period. Using the same f(0) and g(0) values from above, the resulting
density estimate for continental shelf waters (0-200 m deep) is 0.0015
individuals/km\2\ (Table 2 in this document). The density estimate for
waters >1000 m (3,281 ft) deep was estimated as 40% of the 200-1,000 m
(656-3,281 ft) density based on the relative number of sightings in the
two water depth categories. For all water depth and survey area
categories, the maximum beluga density estimates represent the mean
estimates multiplied by four to allow for chance encounters with
unexpected large groups of animals or overall higher densities than
expected.
Beluga density estimates for the west survey area, which is planned
to be surveyed beginning in November, represent the east survey area
estimates multiplied by 0.1 because the Beaufort Sea and north-eastern
Chukchi Sea is believed to be at the edge of the species' range in
November-December. Belugas typically migrate into the Bering Sea for
the winter (Allen and Angliss, 2011) and are not expected to be present
in the study area in high numbers in November-December. Satellite
tagging data support this and indicate belugas migrate out of the
Beaufort Sea in the October-November period (Suydam et al., 2005).
Bowhead Whales: Bowhead whale density estimates were calculated
based on aerial survey data collected in the Beaufort Sea as part of
the BWASP program funded by BOEM. The average density estimate was
based on surveys in October 2007-2010 and the maximum density estimate
was based on surveys conducted in October 1997-2004. The earlier data
were used to calculate the maximum estimate because they include some
years of unusually high numbers of bowhead sightings in the western
Alaskan Beaufort Sea at that time of year. The 2007-2010 data included
25 on-transect sightings collected during 7,482 km (4,649 mi) of effort
over waters 0-200 m (0-656 ft) deep in the eastern Alaskan Beaufort
Sea. The 1997-2004 data included 147 on-transect sightings of 472
individual whales collected during 20,340 km (12,639 mi) of effort over
waters 0-200 m (0-656 ft) deep in the eastern Alaskan Beaufort Sea. An
f(0) correction factor of 2.33 used in the density calculation was the
result of a weighted average of the f(0) values applied to each of the
flights (Richardson and Thomson, 2002). The multiplication of ga(0) =
0.144 and gd(0) = 0.505 correction factors reported in Richardson and
Thomson (2002) gave the g(0) value of 0.0727 used in the density
calculation. The resulting density estimates (0.0942 whales/km\2\ and
0.3719 whales/km\2\) represent the average and maximum densities,
respectively for October for areas of <200 m (656 ft) water depth, and
are referred to below as the reference density for bowhead whales.
Because bowhead whale density is typically higher in continental
shelf waters of the Beaufort Sea in early October, the survey has been
planned to start in the eastern U.S. Beaufort Sea in waters deeper than
1,000 m (3,281 ft; ice conditions permitting), where bowhead density is
expected to be much lower. Survey activity in shallower waters will
proceed from east to west starting later in October as bowhead whales
migrate west out of the Beaufort Sea. The nearshore lines in the east
survey area will be surveyed during late October. Bowhead density in
the east survey area in waters <200 m (656 ft) deep was estimated by
taking ten percent of the reference density above (Table 2 in this
document). This adjustment was based on data from Miller et al. (2002)
that showed a ~90% decrease in bowhead whale abundance in the eastern
Alaskan Beaufort Sea from early to late October.
Bowhead whale densities in intermediate (200-1,000 m [656-3,281
ft]) and deep (>1,000 m [3,281 ft]) water depths in the east survey
area are expected to be quite low. Ninety-seven percent of sightings
recorded by MMS aerial surveys 1997-2004 occurred in areas of water
depth <200 m (656 ft) (Treacy, 1998, 2000, 2002a, 2000b; Monnett and
Treacy, 2005). Therefore, density estimates for areas of water depth
200-1,000 m (656-3,281 ft) were estimated to be ~3% of the values for
areas with depth <200 m (656 ft). This is further supported by Mate et
al. (2000), who found that 87% of locations from satellite-tagged
bowhead whales occurred in areas of water depth <100 m (328 ft). In
areas with water depth >1,000 m (3,281 ft), ~4,225 km (2,625 mi) of
aerial survey effort occurred during October 1997-2004; however, no
bowhead sightings were recorded. The effort occurred over eight years,
so it is unlikely that this result would have been influenced by ice
cover or another single environmental variable that might have affected
whale distribution in a given year. Therefore, a minimal density
estimate (0.0001 whales/km\2\) was used for areas with water depth
>1,000 m (3,281 ft).
Several sources were used to estimate bowhead whale density in the
west survey area, including the north-eastern Chukchi Sea, which is
expected to be surveyed beginning in late October or early November.
Mate et al. (2000) found that satellite-tagged bowhead whales in the
Beaufort Sea travelled at an average rate of 88 km (55 mi) per day. At
that rate, an individual whale could travel across the extent of the
east survey area in four days and across the entire east-west extent of
the survey area in ten days, if it did not stop to feed during its
migration, as bowhead whales have been observed to do earlier in the
year (Christie et al., 2010). Also, Miller et al. (2002) presented a
10-day moving average of bowhead whale abundance in the eastern
Beaufort Sea using data from 1979-2000 that showed a decrease of ~90%
from early to late October. Based on these data, it is expected that
almost all whales that had been in the east survey area during early
October would likely have migrated beyond the survey areas by November-
December. In addition, kernel density estimates and animal tracklines
generated from satellite-tagged bowhead whales, along with acoustic
monitoring data, suggest that few bowhead whales are present in the
proposed survey area in November (near Point Barrow), and no whales
were present in December (ADFG, 2010; Moore et al., 2010). Therefore,
density estimates for the <200 m (656 ft) and 200-1,000 m (656-3,281
ft) water depth categories in the west survey area were estimated to be
one tenth of those estimates for the east survey area. Minimal density
estimates (0.0001 whales/km\2\) were used for areas of water depth
>1,000 m (3,281 ft).
Other Cetaceans: Other cetacean species are not expected to be
present in the area at the time of the planned survey. These species,
including humpback and fin whales, typically migrate during autumn and
are expected to be south of the proposed survey area by the October-
December period. Gray whales have been detected near Point Barrow
during the period of the proposed project, and even throughout the
winter (Moore et al., 2006; Stafford et al., 2007). Authorization for
minimal takes of other cetacean species that are known to occur in the
Beaufort Sea during the summer have been requested in case of a chance
encounter of a few remaining individuals.
[[Page 65082]]
Table 2--Expected Densities of Cetaceans in the Arctic Ocean in October-December by Water Depth and Survey Area
----------------------------------------------------------------------------------------------------------------
Species <200 m 200-1,000 m >1,000 m
----------------------------------------------------------------------------------------------------------------
Beaufort East Survey Area
Beluga whale.......................................... 0.0015 0.1169 0.0468
Harbor porpoise....................................... 0.0001 0.0001 0.0001
Bowhead whale......................................... 0.0094 0.0028 0.0001
Gray whale............................................ 0.0001 0.0001 0.0001
Minke whale........................................... 0.0001 0.0001 0.0001
Beaufort West Survey Area
Beluga whale.......................................... 0.0002 0.0117 0.0047
Harbor porpoise....................................... 0.0001 0.0001 0.0001
Bowhead whale......................................... 0.0009 0.0003 0.0001
Gray whale............................................ 0.0001 0.0001 0.0001
Minke whale........................................... 0.0001 0.0001 0.0001
Chukchi Survey Area
Beluga whale.......................................... 0.0002 ................ ................
Harbor porpoise....................................... 0.0001 ................ ................
Bowhead whale......................................... 0.0009 ................ ................
Gray whale............................................ 0.0001 ................ ................
Minke whale........................................... 0.0001 ................ ................
----------------------------------------------------------------------------------------------------------------
(2) Pinnipeds
In polar regions, most pinnipeds are associated with sea ice, and
typical census methods involve counting pinnipeds when they are hauled
out on ice. In the Beaufort Sea, surveys typically occur in spring when
ringed seals emerge from their lairs (Frost et al., 2004). Depending on
the species and study, a correction factor for the proportion of
animals hauled out at any one time may or may not have been applied
(depending on whether an appropriate correction factor was available
for the particular species and area). By applying a correction factor,
the total density of the pinniped species in an area can be estimated.
Only the animals in water would be exposed to the pulsed sounds from
the airguns; however, densities that are presented generally represent
either only the animals on the ice or all animals in the area.
Therefore, only a fraction of the pinnipeds present in areas where ice
is present (and of sufficient thickness to support hauled-out animals)
would be exposed to seismic sounds during the proposed seismic survey.
Individuals hauled out on ice in close proximity to the vessels are
likely to enter the water as a reaction to the passing vessels, and the
proportion that remain on the ice will likely increase with distance
from the vessels.
Ringed Seals: Ringed seal density for the east survey area for
waters <1000 m (3,281 ft) deep was estimated using vessel-based data
collected in the Beaufort Sea during autumn (Sep-Oct) 2006-2008 and
reported by Savarese et al. (2010; Table 3 in this document).
Correction factors for sightability and availability were used when the
authors calculated the estimates, so no further adjustments were
required. For the east survey area for waters >1000 m (3,281 ft) deep,
few data on seal distribution are available. Harwood et al. (2005)
recorded a ringed seal sighting in the Beaufort Sea in an area where
water depth was >1,000 m (3,281 ft) in September-October 2002 during an
oceanographic cruise. It is therefore possible that ringed seals would
occur in those areas, and their presence would likely be associated
with ephemeral prey resources. If a relatively warm surface eddy formed
that concentrated prey in offshore areas at depths that would be
possible for ringed seals to access, it is possible that seals would be
attracted to it. A warm eddy was found in the northern Beaufort Sea in
October 2002 in an area where water depth was >1,000 m (3,281 ft)
(Crawford, 2010), so it is possible that such an oceanographic feature
might develop again and attract seals offshore. However, it is unclear
whether such a feature would attract many seals, especially since the
marine mammal observers present on the ship in 2002 did not observe
very many seals associated with the offshore eddy. In the absence of
standardized survey data from deep-water areas, but with available data
suggesting densities are likely to be quite low, minimal density
estimates (0.0001 seals/km\2\) were used in areas where water depth is
>1,000 m (3,281 ft). For all water depth categories in the east survey
area, the maximum ringed seal density was assumed to be the mean
estimate multiplied by four to allow for chance encounters with
unexpected large groups of animals or overall higher densities than
expected.
Habitat zones and associated densities were defined differently in
the west survey area, which will be surveyed in November-December,
because more ice is expected to be encountered at that time than in
October (NOAA National Ice Center: www.natice.noaa.gov). The density
estimates for the west survey area were calculated using aerial survey
data collected by Frost et al. (2004) in the Alaskan Beaufort Sea
during the spring. A g(0) correction factor of 0.60 from tagging data
reported by Bengtson et al. (2005) was used to adjust all density
estimates from Frost et al. (2004) described below. Seal distribution
and density in spring, prior to breakup, are thought to reflect
distribution patterns established earlier in the year (i.e., during the
winter months; Frost et al., 2004). Density estimates were highest
(1.00-1.33 seals/km\2\) in areas of water depth 3-35 m (10-115 ft), and
decreased (0-0.77 seals/km\2\) in water >35 m (115 ft) deep. The mean
density estimate used for areas with water depth <35 m (Table 4 in this
document) was estimated using an average of the pack ice estimates
modeled by Frost et al. (2004). The maximum estimate for the same area
is the maximum observed density for areas of water depth 3-35 m (10-115
ft) in Frost et al. (2004). The mean density estimate used for areas
with 35-200 m (115-656 ft) water depth is the modeled value for water
depth >35 m (115 ft) from Frost et al. (2004). The maximum estimate is
the maximum observed density for areas with >35 m (115 ft) water depth
in Frost et al. (2004). Because ringed seal density tends to decrease
with increasing water depth (Moulton et al., 2002; Frost et al., 2004),
ringed seal density was estimated to be minimal in areas of >200 m (656
ft) water depth.
[[Page 65083]]
In the Chukchi Sea, ringed seal densities were taken from offshore
aerial surveys of the pack ice zone conducted in spring 1999 and 2000
(Bengtson et al., 2005). The average density from those two years
(weighted by survey effort) was 0.4892 seals/km\2\. This value served
as the average density while the highest density from the two years,
(0.8100 seals/km\2\ in 1999) was used as the maximum density.
Other Seal Species: Other seal species are expected to be less
frequent in the study area during the period of this survey. Bearded
and spotted seals would be present in the area during summer, and
possibly ribbon seals as well, but they generally migrate into the
southern Chukchi and Bering seas during fall (Allen and Angliss, 2011).
Few satellite-tagging studies have been conducted on these species in
the Beaufort Sea, winter surveys have not been conducted, and a few
bearded seals have been reported over the continental shelf in spring
prior to general breakup. However, three bearded seals tracked in 2009
moved south into the Bering Sea along the continental shelf by November
(Cameron and Boveng, 2009). It is possible that some individuals,
bearded seals in particular, may be present in the survey area. In the
absence of better information from the published literature or other
sources that would indicate significant numbers of any of these species
might be present, minimal density estimates were used for all areas and
water depth categories for these species, with the estimates for
bearded seals assumed to be slightly higher than those for spotted and
ribbon seals (Tables 3 and 4 in this document).
Table 3--Expected Densities (/km\2\) of Pinnipeds in the East Survey Area of the U.S. Beaufort Sea in
October.
----------------------------------------------------------------------------------------------------------------
Species <200 m 200-1,000 m >1,000 m
----------------------------------------------------------------------------------------------------------------
Ringed seal............................................... 0.0840 0.0840 0.0004
Bearded seal.............................................. 0.0004 0.0004 0.0004
Spotted seal.............................................. 0.0001 0.0001 0.0001
Ribbon seal............................................... 0.0001 0.0001 0.0001
----------------------------------------------------------------------------------------------------------------
Table 4--Expected Densities (/km\2\) of Pinnipeds in the Beaufort West and Chukchi Survey Areas of the
Arctic Ocean in November-December.
----------------------------------------------------------------------------------------------------------------
Species <35 m 35-200 m >200 m
----------------------------------------------------------------------------------------------------------------
Beaufort West
Ringed seal........................................... 1.9375 1.0000 0.0004
Bearded seal.......................................... 0.0004 0.0004 0.0004
Spotted seal.......................................... 0.0001 0.0001 0.0001
Ribbon seal........................................... 0.0001 0.0001 0.0001
Chukchi Sea
Ringed seal........................................... ................ 0.4892 ................
Bearded seal.......................................... ................ 0.0004 ................
Spotted seal.......................................... ................ 0.0001 ................
Ribbon seal........................................... ................ 0.0001 ................
----------------------------------------------------------------------------------------------------------------
Potential Number of Takes by Level B Behavioral Harassment
Numbers of marine mammals that might be present and potentially
taken are estimated below based on available data about mammal
distribution and densities at different locations and times of the year
as described above.
The number of individuals of each species potentially exposed to
received levels >=120 dB re 1 [mu]Pa (rms) or >=160 dB re 1 [mu]Pa
(rms), depending on the type of activity occurring, within each portion
of the survey area (east and west) and water depth category was
estimated by multiplying:
The anticipated area to be ensonified to >=120 dB re 1
[mu]Pa (rms) or >=160 dB re 1 [mu]Pa (rms) in each portion of the
survey area (east and west) and water depth category, by
The expected species density in that time and location.
Some of the animals estimated to be exposed, particularly migrating
bowhead whales, might show avoidance reactions before being exposed to
>=160 dB re 1 [mu]Pa (rms). Thus, these calculations actually estimate
the number of individuals potentially exposed to >=160 dB (rms) that
would occur if there were no avoidance of the area ensonified to that
level.
(1) Potential Number of Takes by Seismic Airguns at Received Levels
>=160 dB
The area of water potentially exposed to received levels of airgun
sounds >=160 dB (rms) was calculated by using a GIS to buffer the
planned survey tracklines within each water depth category by the
associated modeled >=160 dB (rms) distances. The expected sound
propagation from the airgun array was modeled by JASCO Applied Research
(Zykov et al., 2010) and is expected to vary with water depth. Survey
tracklines falling within the <100 m (328 ft), 100-1,000 m (328-3,281
ft), and >1,000 m (3,281 ft) water depth categories were buffered by
distances of 27.8 km (17.3 mi), 42.2 km (26.2 mi), and 31.6 km (19.6
mi), respectively. The total area of water that would be exposed to
sound >160 dB (rms) on one or more occasions is estimated to be 209,752
km\2\. A breakdown by water depth classes used in association with
density estimates is presented in Table 5 in this document and Figure 2
of the IHA application.
Based on the operational plans and marine mammal densities
described above, the estimates of marine mammals potentially exposed to
sounds >=160 dB (rms) are presented in Table 5 in this document. For
species likely to be present, the requested numbers are calculated as
described above. For less common species, estimates were set to minimal
numbers to allow for chance encounters. Discussion of the number of
potential exposures is summarized by species in the following
subsections.
It is likely that some members of one endangered cetacean species
(bowhead whale) will be exposed to received
[[Page 65084]]
sound levels >=160 dB (rms) unless bowheads avoid the survey vessel
before the received levels reach 160 dB (rms). However, the late autumn
timing and the design of the proposed survey will minimize the number
of bowheads and other cetaceans that may be exposed to seismic sounds
generated by this survey. The best estimates of the number of whales
potentially exposed to >=160 dB (rms) are 282 and 4,315 for bowheads
and belugas, respectively (Table 5).
The ringed seal is the most widespread and abundant pinniped
species in ice-covered Arctic waters, and there is a great deal of
variation in estimates of population size and distribution of these
marine mammals. Ringed seals account for the vast majority of marine
mammals expected to be encountered, and hence exposed to airgun sounds
with received levels >160 dB (rms) during the proposed marine survey.
Our analysis, based on our use of summer/fall density data, resulted in
an overestimation of take of ringed seals (approximately 60,293 ringed
seals may be exposed to marine survey sounds with received levels >160
dB (rms)) if they do not avoid the sound source. Other pinniped species
are not expected to be present in the proposed survey area in more than
minimal numbers in October-December; however, ION is requesting
authorization for a small number of harassment ``takes'' of species
that occur in the area during the summer months in case a few
individuals are encountered (Table 5 in this document).
It should be noted that there is no evidence that most seals
exposed to airgun pulses with received levels 160 dB re 1 [mu]Pa (rms)
are disturbed appreciably, and even at a received level of 180 dB (rms)
disturbance is not conspicuous (Harris et al., 2001; Moulton and
Lawson, 2002). Therefore, for seals, the estimates of numbers exposed
to >=160 dB re 1 [mu]Pa (rms) greatly exceed the numbers of seals that
will actually be disturbed in any major or (presumably) biologically
significant manner.
Table 5--Estimates of the Possible Numbers of Marine Mammals Exposed to >=160 dB re 1 [mu]Pa (rms) During ION's
Proposed Seismic Program in the Beaufort and Chukchi Seas, October-December 2012
----------------------------------------------------------------------------------------------------------------
Water depth
Cetaceans ------------------------------------------------ Total
<200 m 200-1,000 m >1,000 m
----------------------------------------------------------------------------------------------------------------
Beluga whale.................................... 43 1,195 3,077 4,215
Harbor porpoise................................. 9 2 10 21
Bowhead whale................................... 269 3 10 282
Gray whale...................................... 9 2 10 21
Minke whale..................................... 9 2 10 21
----------------------------------------------------------------------------------------------------------------
Pinnipeds (Beaufort East) Water depth Total
------------------------------------------------
<35 m 35-200 m >200 m
----------------------------------------------------------------------------------------------------------------
Ringed seal..................................... 1,794 805 25 2,624
Bearded seal.................................... 9 4 25 38
Spotted seal.................................... 2 1 6 9
Ribbon seal..................................... 2 1 6 9
----------------------------------------------------------------------------------------------------------------
Pinnipeds (Beaufort West & Chukchi Sea) <35 m 35-200 m >200 m Total
----------------------------------------------------------------------------------------------------------------
Ringed seal..................................... 16,969 40,682 18 57,669
Bearded seal.................................... 4 25 18 47
Spotted seal.................................... 1 6 5 12
Ribbon seal..................................... 1 6 5 12
----------------------------------------------------------------------------------------------------------------
(2) Potential Number of Takes by Icebreaking at Received Levels >=120
dB
As discussed above, based on available information regarding sounds
produced by icebreaking in various ice regimes and the expected ice
conditions during the proposed survey, vessel sounds generated during
ice breaking are likely to have source levels between 175 and 185 dB re
1 [micro]Pa-m. As described above, we have assumed that seismic survey
activity will occur along all of the planned tracklines shown in Figure
1 of ION's IHA application. Therefore, received levels >=160 dB radius
of 26.7-42.2 km (16.6-26.2 mi; depending on water depth) to each side
of all of the survey lines was applied for the calculation. Assuming a
source level of 185 dB re 1 [micro]Pa-m and using the 15logR for
calculating spreading loss of acoustic intensity, icebreaking sounds
may be >=120 dB out to a maximum distance of ~21.6 km (13.4 mi). Thus,
all sounds produced by icebreaking are expected to diminish below 120
dB re 1 [mu]Pa within the zone where we assume mammals will be exposed
to >=160 dB (rms) from seismic sounds. Exposures of marine mammals to
icebreaking sounds with received levels >=120 dB would effectively
duplicate or ``double-count'' animals already included in the estimates
of exposure to strong (>=160 dB) airgun sounds. The planned survey
lines cover a large extent of the U.S. Beaufort Sea, and seismic survey
activity along all those lines has been assumed in the estimation of
takes. Any non-seismic periods, when only icebreaking might occur,
would therefore result in fewer exposures than estimated from seismic
activities.
If refueling of the Geo Arctic is required during the survey and
the Polar Prince transits to and from Canadian waters to acquire
additional fuel for itself, an additional ~200 km (124 mi) of transit
may occur. Most of this transit would likely occur through ice in
offshore waters >200 m (656 ft) in depth. For estimation purposes we
have assumed 25% of the transit will occur in 200-1,000 m (656-3,281
ft) of water and the remaining 75% will occur in >1000 m (3,281 ft) of
water. This results in an estimated ~2,160 km\2\ of water in areas 200-
1,000 m (656-3,281 ft) deep and 6,487 km\2\ in waters >1,000 m (3,281
ft) deep being ensonified to >=120 dB by icebreaking sounds. Using the
density estimates for the east survey
[[Page 65085]]
area shown in Tables 2 and 3, the estimated exposures of cetaceans and
pinnipeds are shown in Table 6 here.
Table 6--Estimates of the Possible Numbers of Marine Mammals Exposed to >=120 dB re 1 [mu]Pa (rms) During
Icebreaking Activities Associated With the Preferred Alternative for Refueling During ION's Proposed Seismic
Program in the Beaufort Sea, October-December 2012
----------------------------------------------------------------------------------------------------------------
Water depth
Species ------------------------------------ Total
200-1,000 m >1,000 m
----------------------------------------------------------------------------------------------------------------
Beluga whale.............................................. 253 320 573
Harbor porpoise........................................... 0 1 1
Bowhead whale............................................. 1 1 2
Gray whale................................................ 0 1 1
Minke whale............................................... 0 1 1
Ringed seal............................................... 181 3 184
Bearded seal.............................................. 1 3 4
Spotted seal.............................................. 0 1 1
Ribbon seal............................................... 0 1 1
----------------------------------------------------------------------------------------------------------------
If the Polar Prince cannot return to port via Canadian waters, then
a transit of ~600 km (373 mi) from east to west across the U.S.
Beaufort would be necessary. Again, it is expected that most of this
transit would likely occur in offshore waters >200 m (656 ft) in depth.
For estimation purposes we have assumed 25% of the transit will occur
in 200-1,000 m (656-3,281 ft) of water and the remaining 75% will occur
in >1,000 m (3,281 ft) of water. This results in an estimated ~3,240
km\2\ of water in areas 200-1,000 m (656-3,281 ft) deep and 9,720 km\2\
in waters >1,000 m (3,281 ft) deep being ensonified to >=120 dB by
icebreaking sounds within each half of the U.S. Beaufort Sea, for a
total of 25,920 km\2\ ensonified across the entire U.S. Beaufort Sea.
Using the density estimates in Tables 2-3, estimated exposures of
cetaceans and pinnipeds are shown in Table 7 here.
Table 7--Estimates of the Possible Numbers of Marine Mammals Exposed to >=120 dB re 1 [mu]Pa (rms) During
Icebreaking Activities Associated With the Secondary Alternative for Refueling During ION's Proposed Seismic
Program in the Beaufort and Chukchi Seas, October-December 2012
----------------------------------------------------------------------------------------------------------------
Water depth
Species ------------------------------------ Total
200-1,000 m >1,000 m
----------------------------------------------------------------------------------------------------------------
Beluga whale.............................................. 417 500 917
Harbor porpoise........................................... 0 2 2
Bowhead whale............................................. 1 2 3
Gray whale................................................ 0 2 2
Minke whale............................................... 0 2 2
Ringed seal............................................... 273 8 281
Bearded seal.............................................. 2 8 10
Spotted seal.............................................. 0 2 2
Ribbon seal............................................... 0 2 2
----------------------------------------------------------------------------------------------------------------
Potential Number of Takes by Level B TTS and Level A Harassment
In the past, because of the likelihood that that individuals will
avoid exposure at received levels and lengths of time associated with
PTS, and because of the anticipated effectiveness of mitigation in the
daytime and in open water, applicants have not requested authorization
for Level A harassment of marine mammals. However, as noted previously,
due to the more limited effectiveness of monitoring and mitigation
measures for animals under ice cover and during long lowlight hours,
but still considering the likelihood that most individuals will avoid
exposure at higher levels and the lower densities of some species, NMFS
is proposing to authorize takes of a small number of marine mammals by
PTS (Level A harassment or injury) when exposed to received noise
levels above 180 and 190 dB re 1 [mu]Pa (rms) for prolonged period,
although this is unlikely to occur.
The methods used below for estimating the number of individuals
potentially exposed to sounds >180 or >190 dB re 1 [micro]Pa (rms),
which are based on over-estimated densities and do not consider
avoidance or mitigation are therefore corrected to account for
avoidance and mitigation to estimate a more reasonable number that
could incur PTS (Level A take) although, for reasons described here and
further below, NMFS does not anticipate that marine mammals will be
injured or harmed by the proposed project.
Only two cetacean species, beluga and bowhead, may be present in
the Alaskan Beaufort Sea late in the survey period or where extensive
ice cover is present. Gray whale vocalizations have been recorded
throughout one winter (2003-2004) in the western Alaskan Beaufort Sea
near Pt. Barrow (Moore et al. 2006). However, the presence of gray
whales in October and November in the Alaskan Beaufort Sea does not
appear to be a regular occurrence or involve a significant number of
animals when it does occur. NMFS therefore does not anticipate
exposures of cetacean species, other than belugas or bowheads, to
received sound levels >=180 dB during periods of ION's in-ice seismic
survey.
Beluga whales have shown avoidance of icebreaking sounds at
relatively low
[[Page 65086]]
received levels. In the Canadian Arctic, belugas showed initial
avoidance of icebreaking sounds at received levels from 94-105 dB in
the 20--1,000 Hz band, although some animals returned to the same
location within 1-2 days and tolerated noise levels as high as 120 dB
in that band (Finley et al., 1990). Playback experiments of icebreaker
sounds resulted in 35% of beluga groups showing avoidance at received
levels between 78-84 dB in the 1/3-octave band centered at 5,000 Hz, or
8-14 dB above ambient levels (Richardson et al., 1995b). Based on these
results, it was estimated that reactions by belugas to an actual
icebreaker would likely occur at ~10 km (6.2 mi) under similar
conditions. Erbe and Farmer (2000) estimated that zones of disturbance
from icebreaking sounds could extend 19-46 km (12-28.6 mi) depending on
various factors. Erbe and Farmer (2000) also estimated that a beluga
whale would have to remain within 2 km (1.2 mi) of an icebreaker
backing and ramming for over 20 min to incur small TTS (4.8 dB), and
within 120 m for over 30 min to incur more significant TTS (12-18 dB).
Therefore, we expect that the probability of a beluga whale to
experience TTS is extremely low.
Aerial and vessel based monitoring of seismic surveys in the
central Beaufort Sea showed significant avoidance of active airguns by
belugas. Results of the aerial monitoring suggested an area of
avoidance out to 10-20 km (6.2-12.4 mi) around an active seismic source
with higher than expected sighting rates observed at distances 20-30 km
(12.4-18.6 mi) from the source (Miller et al. 1999; 2005). The nearest
aerial ``transect'' beluga sighting during seismic activity was at a
distance of 7.8 km (4.8 mi). Only seven beluga sightings were recorded
from the survey vessel during the entire study, three of which occurred
during airgun activity. Two of the seismic period sightings were made
at the beginning of active airgun periods and the other was during
seismic testing of a limited number of guns. These sightings occurred
at distances between 1.54 km and 2.51 km from the vessel. Similarly,
few beluga whales were observed near seismic surveys in the Alaskan
Beaufort Sea in 1996-1998 (Richardson 1999), although the beluga
migration corridor is typically well offshore of where most of the
seismic survey occurred. Observers on seismic and associated support
vessels operating in the Alaskan Beaufort Sea during 2006-2008 seasons
reported no beluga sightings during seismic or non-seismic periods,
suggesting avoidance of both seismic and vessel sounds (Savarese et
al., 2010). No mitigation measures during seismic operations (power
down or shut down of airgun arrays) have been required as a result of
beluga sightings during surveys in the Chukchi or Beaufort seas in
2006-2009 (Ireland et al., 2007a, 2007b; Patterson et al., 2007, Funk
et al., 2008, Ireland et al., 2009b, Reiser et al., 2010).
Based on the reported avoidance of vessel, icebreaking, and seismic
sounds by beluga whales, and the low and seasonally decreasing density
during the time of the proposed survey, the likelihood of beluga whales
occurring within the >=180 dB zone during the proposed project is
extremely low. A cautionary estimate that assumes 10% of belugas will
show no avoidance of the 180 dB zone results in an estimate of 23
beluga whales exposed to sounds >=180 dB (based on the densities
described above and the area of water that may be ensonified to >=180
dB) during the proposed project.
Bowhead whales have shown similar avoidance of vessel and seismic
sounds. Less information is available regarding avoidance of
icebreaking sounds; however, avoidance of the overall activity was
noted during intensive icebreaking around drill sites in the Alaskan
Beaufort Sea in 1992. Migrating bowhead whales appeared to avoid the
area of drilling and icebreaking by ~25 km (15.5 mi) (Brewer et al.,
1993). Also, monitoring of drilling activities in a previous year,
during which much less icebreaking occurred, showed avoidance by
migrating bowheads out to ~20 km (12.4 mi). Therefore, the relative
influence of icebreaking versus drilling sounds is difficult to
determine.
Similarly, migrating bowheads avoided the area within ~20 km (12.4
mi) of nearshore seismic surveys, and showed less avoidance extending
to ~30 km (18.6 mi) (Miller et al., 1999). Only 1 bowhead was observed
from the survey vessel during the three seasons (1996-1998) when
seismic surveys continued into September. Bowheads not actively engaged
in migration have shown less avoidance of seismic operations. During
seismic surveys in the Canadian Beaufort Sea in late August and early
September bowhead whales appeared to avoid an area within ~2 km (1.2
mi) of airgun activity (Miller and Davis, 2002) and sightings from the
survey vessel itself were common (Miller et al., 2005). Vessel based
sightings showed a statistically significant difference of ~600 m
(1,969 ft) in the mean sighting distances of bowheads (relative to the
survey vessel) between periods with and without airgun activity. This,
along with significantly lower sighting rates of bowhead whales during
periods of airgun activity, suggests that bowheads still avoided close
approach to the area of seismic operation (Miller and Davis, 2002).
Results from vessel-based and aerial monitoring in the Alaskan Beaufort
Sea during 2006-2008 were similar to those described above (Funk et
al., 2010). Sighting rates from seismic vessels were significantly
lower during airgun activity than during non-seismic periods. Support
vessels reported 12 sightings of bowhead whales in areas where received
levels from seismic were >=160 dB (Savarese et al., 2010). Aerial
surveys reported bowhead whales feeding in areas where received levels
of seismic sounds were up to 160 dB. Bowheads were not observed in
locations with higher received levels (Christie et al., 2010). Based on
four direct approach experiments in northern Alaskan waters, Ljungblad
et al. (1988) reported total avoidance of seismic sounds at received
sound levels of 152, 165, 178, and 165 dB.
The available information summarized above suggests that bowhead
whales are very likely to avoid areas where received levels are >=180
dB re 1 [mu]Pa (rms). Again, making a cautionary assumption that as
many as 10% of bowheads may not avoid the 180 dB zone around the
airguns, we calculate that 6 individuals could be exposed to >=180 dB
(based on the densities described above and the area of water that may
be ensonified to >=180 dB). During seismic surveys in the Alaskan
Beaufort Sea in 2007 and 2008, 5 power downs of the full airgun array
were made due to sightings of bowhead or unidentified mysticete whales
(8 total individuals) within the >=180 dB exclusion zone. These
sightings occurred during >8000 km (4,971 mi) of survey effort in good
conditions plus additional effort in poor conditions (Savarese et al.,
2010), resulting in an estimated 0.625 sightings within the 180 dB
distance per 1,000 km (620 mi) of seismic activity. Even without
allowance for the reduced densities likely to be encountered in October
and especially November, or for the fact that observers will be on duty
during all daylight hours and will call for mitigation actions if
whales are sighted within or near the 180 dB distance, this rate would
suggest that fewer than 8 bowheads may occur within the >=180 dB zone
during the proposed survey.
For seals (principally ringed seals), the proportion exhibiting
avoidance is lower than for cetaceans, and thus the received level at
which avoidance becomes evident is higher. However, some survey results
have shown a statistically significant avoidance of the
[[Page 65087]]
190 dB re 1 [mu]Pa (rms) zone, and an assumption that numbers exposed
to >=190 dB could be calculated from ``non-seismic'' density data is
not inappropriate. Using similar reasoning as described above for
cetaceans, we have limited these estimates to ringed seals as the
presence of other pinniped species is very unlikely during the times
and locations when exposures to >=190 dB may have an increased
likelihood of occurrence.
Monitoring work in the Alaskan Beaufort Sea during 1996-2001
provided considerable information regarding the behavior of seals
exposed to seismic pulses (Harris et al., 2001; Moulton and Lawson,
2002). The combined results suggest that some seals avoid the immediate
area around seismic vessels. In most survey years, ringed seal
sightings averaged somewhat farther away from the seismic vessel when
the airguns were operating than when they were not (Moulton and Lawson,
2002). Also, seal sighting rates at the water surface were lower during
airgun array operations than during no-airgun periods in each survey
year except 1997. However, the avoidance movements were relatively
small, on the order of 100 m (328 ft) to (at most) a few hundreds of
meters, and many seals remained within 100-200 m (328-656 ft) of the
trackline as the operating airgun array passed by.
During more recent seismic surveys in the Arctic (2006-2009),
Reiser et al. (2009) also reported a tendency for localized avoidance
of areas immediately around the seismic source vessel along with
coincident increased sighting rates at support vessels operating 1-2 km
(0.62-1.2 mi) away. However, pinnipeds were sighted within the 190 dB
zone around the operating airguns more frequently than were cetaceans
within the 180 dB zone. Assuming that 25% of the ringed seals
encountered may not avoid the 190 dB zone as the airguns approach, we
calculate that ~277 individuals could be exposed to >=190 dB (based on
the densities described above and the area of water that may be
ensonified to >=190 dB). As an alternative estimate, during the same
>8,000 km (4,971 mi) of monitoring effort in the Alaskan Beaufort Sea
reported above regarding bowhead whales, 42 observations of seals
within the 190 dB zone caused power downs of the airguns. This was
~5.25 power downs per 1,000 km (620 mi) of seismic survey effort. Even
without allowance for the reduced densities of seals likely to be
encountered in October-November or for the fact that observers will be
on duty during all daylight hours and will call for mitigation actions
if necessary, this rate would suggest that as many as 38 seals may
occur within the >=190 dB zone during the proposed survey.
However, as stated earlier, in most circumstances marine mammals
would avoid areas where intense noise could cause injury, including
PTS. Although approximately 23 beluga whales, 8 bowhead whales, and 38
seals (presumably all ringed seals) could theoretically be exposed to
received levels above 180 dB re 1 [mu] Pa (for whales) and 190 dB re 1
[mu] Pa (for seals), most of them are likely to avoid areas of intense
noise and would not incur TTS or PTS (injury). In the unlikely case a
small number of individuals animals did not avoid the intense noise,
then TTS or even PTS could occur. Assuming that 10% of the individuals
that were initially exposed to received levels above 180 dB re 1 [mu]
Pa (for beluga and bowhead whales) and 190 dB re 1 [mu] Pa (for ringed
seals) do not vacate the area, and subsequent exposure leads to some
degree of PTS, then approximately 3 beluga whales, 1 bowhead whale, and
4 ringed seals could be taken by Level A harassment. However, NMFS
considers this estimate to be very conservative as explained above.
Estimated Take Conclusions
Cetaceans--Effects on cetaceans are generally expected to be
restricted to avoidance of an area around the seismic survey and short-
term changes in behavior, falling within the MMPA definition of ``Level
B harassment,'' and possibly mild TTS (Level B harassment), or PTS
(Level A harassment), though the latter is not likely.
Using the 160 dB (for pulse) and 120 dB (for non-pulse) criteria,
the average estimates of the numbers of individual cetaceans exposed to
sounds 160 dB and 120 dB re 1 [mu]Pa (rms) represent varying
proportions of the populations of each species in the Beaufort Sea and
adjacent waters. For species listed as ``endangered'' under the ESA,
the estimates include approximately 284 bowheads. This number is
approximately 1.86% of the Bering-Chukchi-Beaufort population of
>15,233 assuming 3.4% annual population growth from the 2001 estimate
of >10,545 animals (Zeh and Punt 2005). For other cetaceans that might
occur in the vicinity of the marine seismic survey in the Chukchi Sea,
they also represent a very small proportion of their respective
populations. The average estimates of the number of beluga whales,
harbor porpoises, gray whales, and minke whales that might be exposed
to 160 dB and 120 dB re 1 [mu] Pa (rms) are 5,232, 23, 23,
and 23, when the secondary alternative for refueling is being
considered. These numbers represent 13.33%, 0.05%, 0.12%, and 1.87% of
these species' respective populations in the proposed action area. If
ION selects the preferred alternative for refueling, the estimated
takes for beluga would be reduced to 4,888 animals, or 12.45% of the
population, which are still based on overestimated densities of these
animals for the winter season.
Seals--A few seal species are likely to be encountered in the study
area, but ringed seal is by far the most abundant in this area. The
average estimates of the numbers of individuals exposed to sounds at
received levels 160 dB and 120 dB re 1 [mu] Pa (rms) during
the proposed icebreaking seismic survey are as follows: ringed seals
(60,574), bearded seals (95), spotted seals (23), and ribbon seals
(23), when the secondary alternative for refueling is being considered.
These numbers represent 24.33%, 0.04%, 0.04%, and 0.05% of Alaska
stocks of ringed, bearded, spotted, and ribbon seals. If ION selects
the preferred alternative for refueling, the estimated takes for
ringed, bearded, spotted, and ribbon seals would drop to 60,477, 89,
22, and 22, respectively, which in turn represent 24.29%, 0.04%, 0.04%,
0.04% of Alaska stocks of these species, based on overestimated
densities of these animals for the winter season.
Negligible Impact and Small Numbers Analysis and Determination
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.
Most of the takes from ION's proposed icebreaking seismic surveys
are expected to be Level B harassment, i.e., behavioral disturbance
with a slight likelihood of mild TTS. However, it is possible that PTS
(Level A harassment) given the lowered effectiveness of monitoring
measures are during extensive ice coverage and prolonged periods of
darkness. Although it is possible that some individual marine mammals
may be exposed to sounds from marine survey activities more than
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once, this is not expected to happen extensively since both the animals
and the survey vessels will be moving constantly in and out of the
survey areas. Therefore, the degree of TTS and PTS, if incurred, is
expected to be minor (low intensity--a few dBs of loss at certain
frequencies), and the TTS is expected to be brief (minutes to hours)
before full recovery. No serious injury or mortality is expected as a
result of the proposed seismic survey, and neither is proposed to be
authorized.
Of the nine marine mammal species likely to occur in the proposed
marine survey area, only the bowhead whale is listed as endangered
under the ESA. This species is also designated as ``depleted'' under
the MMPA. Despite these designations, the Bering-Chukchi-Beaufort 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), even in the face
of ongoing industrial activity and subsistence harvest. There is no
critical habitat designated in the U.S. Arctic for the bowhead whale.
Certain stocks or populations of gray and beluga whales and spotted
seals are listed as endangered or are proposed for listing under the
ESA; however, none of those stocks or populations occur in the proposed
activity area. On December 10, 2010, NMFS published a notice of
proposed threatened status for subspecies of the ringed seal (75 FR
77476) and a notice of proposed threatened and not warranted status for
subspecies and distinct population segments of the bearded seal (75 FR
77496) in the Federal Register. Neither of these two ice seal species
is currently considered depleted under the MMPA.
Level B Behavioral Harassment
Most of the bowhead whales encountered during the summer will
likely show overt disturbance (avoidance) only if they receive airgun
sounds with levels >=160 dB re 1 [mu] Pa (rms). Odontocete reactions to
seismic energy 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). Both
belugas and bowhead whales are expected to occur in much smaller
numbers in the vicinity of the proposed seismic survey area during the
proposed survey. In addition, due to the constant movement of the
seismic survey vessel, the duration of the cetaceans' exposure to noise
from seismic impulses would be brief. For the same reason, it is
unlikely that any individual animal would be exposed to high received
levels multiple times.
Taking into account the mitigation measures that are planned,
effects on cetaceans are generally expected to be restricted to
avoidance of a limited area around the survey operation and short-term
changes in behavior, falling within the MMPA definition of ``Level B
harassment,'' with only limited potential occurrences of TTS (Level B
harassment) and PTS (Level A harassment).
Furthermore, the estimated numbers of animals potentially exposed
to sound levels sufficient to cause appreciable disturbance are small
percentages of the population sizes in the Bering-Chukchi-Beaufort
seas, as described above.
Finally, as discussed above, since ION is not likely to start its
proposed in-ice seismic survey until mid- to late-October when most of
the cetaceans (especially bowhead whales) have moved out of the area,
the actual take numbers are expected to be much lower.
The many reported cases of apparent tolerance by cetaceans from
seismic exploration, vessel traffic, and some other human activities
show that co-existence is possible. Mitigation measures such as
controlled vessel speed, dedicated PSOs, non-pursuit, and shutdowns 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.
Some individual pinnipeds may be exposed to sound from the proposed
marine surveys more than once during the time frame of the project.
However, as discussed previously, due to the constant movement of the
survey vessel, the probability of an individual pinniped being exposed
multiple times is much lower than if the source is stationary.
Therefore, NMFS has determined that the pinnipeds' exposure to sounds
produced by the proposed marine seismic survey in the Beaufort and
Chukchi Seas is mostly expected to result in no more than Level B
harassment and is anticipated to have no more than a negligible impact
on the animals.
The estimated Level B behavioral takes proposed to be authorized
represent up to 12.45% of the Beaufort Sea population of approximately
39,258 beluga whales (Allen and Angliss, 2010), up to 0.04% of Bering
Sea stock of approximately 48,215 harbor porpoises, 0.12% of the
Eastern North Pacific stock of approximately 19,126 gray whales, 1.86%
of the Bering-Chukchi-Beaufort population of 15,233 individuals
assuming 3.4 percent annual population growth from the 2001 estimate of
10,545 animals (Zeh and Punt, 2005), and 1.78% of the Alaska stock of
approximately 1,233 minke whales. The take estimates presented for
ringed, bearded, spotted, and ribbon seals represent up to 24.29, 0.04,
0.04, and 0.04 percent of U.S. Arctic stocks of each species,
respectively. These estimates represent the percentage of each species
or stock that could be taken by Level B behavioral harassment if each
animal is taken only once. Although we have estimated that up to 24.29%
of ringed seals could be taken as a result of the proposed seismic
survey activity, it is important to note that the population densities
for marine mammals within the proposed survey area are overestimates.
As explained above, because of the lack of fall/winter data, NMFS and
ION had to rely on the summer/fall density data to calculate expected
densities of marine mammals and potential take estimates. Our analysis
has led us to conclude that in the case of ringed seals (and several
other species), the number of ringed seals that would occur in the
project area during the proposed survey period is expected to be much
lower and thus, far fewer ringed seals are actually expected to be
taken as a result of ION's in-ice seismic survey in the Beaufort Sea.
Furthermore, it is likely that individual animals could be taken
multiple times and be counted as different individuals, thus inflating
the percentage of unique individuals that would be affected. Finally,
as discussed earlier, the effects to marine mammals that would result
from Level B behavioral harassment are expected to be minor and brief,
and mostly involve animals temporarily changing their behavior and
vacating the proximity of the survey area briefly as the survey vessel
and icebreaker approach. Marine mammals are expected to resume their
normal activities and reoccupy the area as soon as the vessels move
away. Additionally, since the proposed in-ice seismic survey is planned
outside the breeding season of marine mammals, no impacts on calves or
pups are expected. Further, there is no known marine
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mammal feeding activity during the period of ION's in-ice seismic
survey activities. Therefore, any effects to marine mammals are not
expected to be biologically significant on either the individual or
population level for thess species. In addition, the mitigation and
monitoring measures (described previously in this document) included in
the IHA are expected to further reduce any potential disturbance to
marine mammals.
Hearing Impairment (TTS, Level B Harassment, or PTS, Level A
Harassment)
Most cetaceans (and particularly Arctic cetaceans) show relatively
high levels of avoidance when received sound pulse levels exceed 160 dB
re 1 [mu] Pa (rms), and it is uncommon to sight Arctic cetaceans within
the 180 dB radius, especially for prolonged duration. Results from
monitoring programs associated with seismic activities in the Arctic
indicate that cetaceans respond in different ways to sound levels lower
than 180 dB. These results have been used by agencies to support
monitoring requirements within distances where received levels fall
below 160 dB and even 120 dB. Thus, very few animals would be exposed
to sound levels of 180 dB re 1 [mu] Pa (rms) regardless of
detectability by PSOs. Avoidance varies among individuals and depends
on their activities or reasons for being in the area, and occasionally
a few individual Arctic cetaceans will tolerate sound levels above 160
dB. Tolerance of levels above 180 dB is infrequent regardless of the
circumstances, and marine mammals exposed to levels this high are
expected to avoid the source, thereby minimizing the probability of
TTS. Therefore, a calculation of the number of cetaceans potentially
exposed to >180 dB that is based simply on density would be a gross
overestimate of the actual numbers exposed to 180 dB. Such calculations
would be misleading unless avoidance response behaviors were taken into
account to estimate what fraction of those originally present within
the soon-to-be ensonified to >180 dB zone (as estimated from density)
would still be there by the time levels reach 180 dB.
It is estimated that up to 1 bowhead whale and 3 beluga whales
could be exposed to received noise levels above 180 dB re 1 [mu] Pa
(rms), and 4 ringed seals could be exposed to received noise levels
above 190 dB re 1 [mu] Pa (rms) for durations long enough to cause TTS
if the animals are not detected in time to have mitigation measures
implemented (or even PTS if such exposures occurred repeatedly). None
of the other species are expected to be exposed to received sound
levels anticipated to cause TTS or PTS.
Marine mammals that are taken by TTS are expected to receive minor
(in the order of several dBs) and brief (minutes to hours) temporary
hearing impairment because (1) animals are not likely to remain for
prolonged periods within high intensity sound fields, and (2) both the
seismic vessel and the animals are constantly moving, and it is
unlikely that the animal will be moving along with the vessel during
the survey. Although repeated experience to TTS could result in PTS
(Level A harassment), for the same reasons discussed above, even if
marine mammals experience PTS, the degree of PTS is expected to be
mild, resulting in a few dB elevation of hearing threshold. Therefore,
even if a few marine mammals receive TTS or PTS, the degree of these
effects are expected to be minor and, in the case of TTS, brief, and
are not expected to be biologically significant for the population or
species.
Effects on Marine Mammal Habitat
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 marine survey
activities, any missed feeding opportunities in the direct project area
would be minor based on the fact that other feeding areas exist
elsewhere. For bowhead whales, the majority of the population would
have migrated past many of the feeding areas of the central Beaufort
Sea prior to the initiation of activities by ION.
The effects of icebreaking activity are not expected to result in
significant modification to marine mammal habitat. Although it is
expected that the ice coverage would be \8/10\th to \10/10\th, the ice
in the proposed project area is loose annual ice during the time of the
proposed in-ice seismic survey activity. Therefore, ice floes being
broken and pushed aside from the icebreaker are expected to rejoin
behind the seismic survey path. In addition, no ice seal lairs are
expected during the period of ION's in-ice seismic survey in the
Beaufort and Chukchi Seas.
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 ION's 2012 in-ice seismic survey in the
Beaufort and Chukchi Seas may result in the incidental take of small
numbers of marine mammals, by Level A and Level B harassment only, and
that the 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 ION's 2012 in-ice marine seismic survey in
the Beaufort and Chukchi Seas 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 ION's CAA and POC. ION has adopted a
spatial and temporal strategy for its Beaufort and Chukchi Seas in-ice
seismic survey operation that is intended to avoid subsistence
activities. ION plans to start its seismic survey after the fall
bowhead harvests have concluded for the communities of Kaktovik and
Nuiqsut, and its seismic survey is expected to occur far offshore from
regular ringed seal hunts. Although hunting may still be occurring in
Barrow, ION has agreed to work in the eastern part of the survey area
first so as not to overlap with areas used by hunters in Barrow. The
late November bowhead harvests on St. Lawrence Island should not be
affected by ION's vessel transits through the Bering Strait, which
would not occur until the conclusion of the survey in early to mid-
December. No other subsistence activity is expected to occur during
ION's proposed seismic survey period.
Based on the measures described in ION's POC and CAA, the proposed
mitigation and monitoring measures (described earlier in this
document), and the project design itself, NMFS has determined there
will not be an unmitigable adverse impact on subsistence uses from
ION's icebreaking marine seismic survey in the Beaufort and Chukchi
Seas.
Endangered Species Act (ESA)
The bowhead whale is the only marine mammal species currently
listed as endangered under the ESA that could occur during ION's
proposed in-ice seismic survey period. In addition, there are two
marine mammal species that are currently being proposed for listing
under the ESA with confirmed occurrence in the proposed project area:
ringed and bearded seals. NMFS'
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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 ION under section 101(a)(5)(D) of the MMPA
for this activity. A Biological Opinion was issued on October 17, 2012,
which concludes that issuance of the IHA is not likely to jeopardize
the continued existence of the ESA-listed marine mammal species and
species proposed for ESA-listing. 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 ION
to take marine mammals incidental to conducting in-ice seismic survey
in the Beaufort and Chukchi Seas during fall/winter 2012. 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 ION
to take marine mammals incidental to its in-ice seismic survey in the
Beaufort and Chukchi Seas, Alaska, provided the previously mentioned
mitigation, monitoring, and reporting requirements are incorporated.
Dated: October 17, 2012.
Helen M. Golde,
Acting Director, Office of Protected Resources, National Marine
Fisheries Service.
[FR Doc. 2012-26103 Filed 10-23-12; 8:45 am]
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