Takes of Marine Mammals Incidental to Specified Activities; Taking Marine Mammals Incidental to Marine Seismic Survey in the Chukchi Sea, Alaska, 35507-35532 [2013-13988]

Agencies

• DEPARTMENT OF COMMERCE
• National Oceanic and Atmospheric Administration

[Federal Register Volume 78, Number 113 (Wednesday, June 12, 2013)]
[Notices]
[Pages 35507-35532]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: 2013-13988]



[[Page 35507]]

Vol. 78

Wednesday,

No. 113

June 12, 2013

Part IV





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 Chukchi Sea, 
Alaska; Notice

Federal Register / Vol. 78 , No. 113 / Wednesday, June 12, 2013 / 
Notices

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DEPARTMENT OF COMMERCE

National Oceanic and Atmospheric Administration

RIN 0648-XC563


Takes of Marine Mammals Incidental to Specified Activities; 
Taking Marine Mammals Incidental to Marine Seismic Survey in the 
Chukchi Sea, Alaska

AGENCY: National Marine Fisheries Service (NMFS), National Oceanic and 
Atmospheric Administration (NOAA), Commerce.

ACTION: Notice; proposed incidental harassment authorization; request 
for comments.

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SUMMARY: NMFS received an application from TGS-NOPEC Geophysical 
Company ASA (TGS) for an Incidental Harassment Authorization (IHA) to 
take marine mammals, by harassment only, incidental to a marine 2-
dimensional (2D) seismic survey program in the Chukchi Sea, Alaska, 
during the open water season of 2013. Pursuant to the Marine Mammal 
Protection Act (MMPA), NMFS is requesting comments on its proposal to 
issue an IHA to TGS to take, by Level B harassment, 12 species of 
marine mammals during the specified activity.

DATES: Comments and information must be received no later than July 12, 
2013.

ADDRESSES: Comments on the application 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. The mailbox address for providing 
email comments is ITP.guan@noaa.gov. NMFS is not responsible for email 
comments sent to addresses other than the one provided here. Comments 
sent via email, including all attachments, must not exceed a 10-
megabyte file size.
    Instructions: All comments received are a part of the public record 
and will generally be posted to https://www.nmfs.noaa.gov/pr/permits/incidental.htm#applications without change. All Personal Identifying 
Information (for example, name, address, etc.) voluntarily submitted by 
the commenter may be publicly accessible. Do not submit Confidential 
Business Information or otherwise sensitive or protected information.
    The application used in this document may be obtained by visiting 
the internet at: https://www.nmfs.noaa.gov/pr/permits/incidental.htm#applications. Documents cited in this notice may also 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.

SUPPLEMENTARY INFORMATION: 

Background

    Sections 101(a)(5)(A) and (D) of the MMPA (16 U.S.C. 1361 et seq.) 
direct the Secretary of Commerce to allow, upon request, the 
incidental, but not intentional, taking of small numbers of marine 
mammals by U.S. citizens who engage in a specified activity (other than 
commercial fishing) within a specified geographical region if certain 
findings are made and either regulations are issued or, if the taking 
is limited to harassment, a notice of a proposed authorization is 
provided to the public for review.
    Authorization for incidental takings shall be granted if NMFS finds 
that the taking will have a negligible impact on the species or 
stock(s), will not have an unmitigable adverse impact on the 
availability of the species or stock(s) for subsistence uses (where 
relevant), and if the permissible methods of taking and requirements 
pertaining to the mitigation, monitoring and reporting of such takings 
are set forth. NMFS has defined ``negligible impact'' in 50 CFR 216.103 
as ``...an impact resulting from the specified activity that cannot be 
reasonably expected to, and is not reasonably likely to, adversely 
affect the species or stock through effects on annual rates of 
recruitment or survival.''
    Section 101(a)(5)(D) of the MMPA established an expedited process 
by which citizens of the U.S. can apply for an authorization to 
incidentally take small numbers of marine mammals by harassment. 
Section 101(a)(5)(D) establishes a 45-day time limit for NMFS review of 
an application followed by a 30-day public notice and comment period on 
any proposed authorizations for the incidental harassment of marine 
mammals. Within 45 days of the close of the comment period, NMFS must 
either issue or deny the authorization.
    Except with respect to certain activities not pertinent here, the 
MMPA defines ``harassment'' as: Any act of pursuit, torment, or 
annoyance which (i) has the potential to injure a marine mammal or 
marine mammal stock in the wild [``Level A harassment'']; or (ii) has 
the potential to disturb a marine mammal or marine mammal stock in the 
wild by causing disruption of behavioral patterns, including, but not 
limited to, migration, breathing, nursing, breeding, feeding, or 
sheltering [``Level B harassment''].

Summary of Request

    On December 3, 2012, NMFS received an application from TGS 
requesting an authorization for the harassment of small numbers of 
marine mammals incidental to conducting an open-water 2D seismic survey 
in the Chukchi Sea off Alaska. After addressing comments from NMFS, TGS 
modified its application and submitted a revised application on April 
1, 2013, and a revised marine mammal monitoring and mitigation plan on 
April 15, 2013, with additional clarification on May 7, 2013. TGS' 
proposed activities discussed here are based on its April 1, 2013, IHA 
application and April 15, 2013, marine mammal monitoring and mitigation 
measures.

Description of the Specified Activity

    TGS proposes to conduct approximately 9,600 km of marine 2D seismic 
surveys along pre-determined lines in U.S. waters and international 
waters of the Chukchi Sea (Figure 1 of TGS' IHA application) during the 
2013 open water season. The purpose of the proposed seismic program is 
to gather geophysical data using a 3,280 in\3\ seismic source array and 
an 8,100-m long hydrophone solid streamer towed by the seismic vessel. 
Results of the 2D seismic program would be used to identify and map 
potential hydrocarbon-bearing formations and the geologic structures 
that surround them.
    TGS plans to enter the U.S. Chukchi Sea sometime between 15 July 
and 5 August, 2013. Approximately 35 days of seismic operations are 
expected to occur over a period of about 45-60 days in U.S. Chukchi 
Sea. In addition, up to 33 days of seismic operations may occur in 
international waters (depending on ice and weather conditions). Seismic 
operations are proposed to occur along pre-determined track lines at 
speeds of about four to five knots. Seismic operations would be 
conducted up to 24 hours per day as possible except as potentially 
needed for shut-down mitigation for marine mammals. The full 3,280 
in\3\ airgun array would only be firing during seismic acquisition 
operations on and near the end and start of survey lines; during turns 
and transits between seismic lines, a single ``mitigation'' airgun (60 
in\3\ or smaller) is proposed to be operated.
    Two vessels would be used during the survey: (1) A seismic 
operations vessel that would tow the seismic source array hydrophone 
solid streamer, and (2) a smaller vessel that will be used to search 
for marine mammals and scout

[[Page 35509]]

for ice and other navigation hazards ahead of the seismic vessel. In 
the event of an emergency, the scout vessel may be used to support the 
seismic vessel. In this extraordinary circumstance, all seismic 
activity will cease since the scout vessel will no longer be devoted to 
monitoring the exclusion zones.
    The seismic vessel will tow a compressed-air seismic source array 
of 28 Bolt 1900 LLXT airguns with a total discharge volume of 3,280 
in\3\. The airguns range in volume from 40 in\3\ to 300 in\3\ and are 
arranged in a geometric lay-out of three sub-arrays that will be towed 
approximately 200 m behind the vessel at a depth of 6 m. The seismic 
source would discharge every 25 m (82 ft) or approximately every 10 
seconds. Additional details regarding seismic acquisition parameters 
are provided in TGS' IHA application. To ascertain whether the seismic 
source array is operating correctly, the full volume will be enabled 
for 1 km from the start of every line (i.e., a run in). To ensure full 
fold data acquisition the vessel will require a 4 km run out at the 
conclusion of each line. TGS states that gravity and magnetic data will 
also be passively acquired during the survey by measuring gravity and 
magnetic variations while traversing the lines (no acoustics are 
involved with these methods).
    The acoustic source level of the proposed 3,280 in\3\ seismic 
source array was predicted using JASCO's airgun array source model 
(AASM) based on data collected from three sites chosen in the project 
area by JASCO. Water depths at the three sites were 17, 40, and 100 m. 
JASCO applied its Marine Operations Noise Model (MONM) to estimate 
acoustic propagation of the proposed seismic source array and the 
associated distances to the 190, 180 and 160 dB (rms) re 1 [mu]Pa 
isopleths. The resulting isopleths modeled for the 180 and 190 dB (rms) 
re 1 [mu]Pa exclusion zone distances for cetaceans and pinnipeds, 
respectively, differed with the three water depths. An additional 10 
percent distance buffer was added by JASCO to these originally modeled 
distances to provide larger, more protective exclusion zone radii 
distances that will be adhered to during the project (Table 1).
    The estimated distances to the 190, 180 and 160 dB re 1[mu]Pa (rms) 
isopleths for the single 60 in3 airgun (the largest single airgun that 
would be used as a ``mitigation'' gun) were measured by JASCO during a 
monitoring sound source verification (SSV) study conducted for Statoil 
in 2010 in the Chukchi Sea during the open water season of 2010 (Blees 
et al. 2010). Results indicated that the distance to the 190 dB 
isopleth was 13 m, the 180 dB isopleth distance was 68 m, and the 160 
dB isopleth distance was 1,500 m (all dB (rms) re 1 [mu]Pa).

 Table 1--Modeled Distances in (Meters) To Received Sound Levels for the
 TGS' 3,280 in\3\ Airgun Array in Waters With Three Different Depths in
                             the Chukchi Sea
------------------------------------------------------------------------
                                            Received sound level  (dB re
                                                  1 [micro]Pa rms)
             Water depths (m)              -----------------------------
                                               190       180       160
------------------------------------------------------------------------
17-40.....................................       930     2,200     8,500
40-100....................................       920     2,500     9,900
>100......................................       430     2,400    15,000
------------------------------------------------------------------------

    Both vessels would use industry-standard echosounder/fathometer 
instruments to continuously monitor water depth for navigation purposes 
while underway. These instruments are the same as those used aboard all 
large vessels to obtain information on water depths and potential 
navigation hazards for vessel crews during routine navigation 
operations. Navigation echosounders direct a single, high-frequency 
acoustic signal that is focused in a narrow beam directly downward to 
the sea floor. The reflected sound energy is detected by the 
echosounder instrument which then calculates and displays water depth 
to the user. Typical source levels of these types of navigational 
echosounders are generally 180-200 dB re 1 [mu]Pa at 1 m.
    One navigational echosounder would be used by the seismic vessel 
and another one will be used by the scout vessel. The echosounder used 
by the seismic vessel will consist of a downward-facing single-beam 
(Kongsberg EA600) that operates at frequencies of 18 to 200 kHz (output 
power 1-2 kilowatt [kW]). Associated pulse durations are 0.064 and 
4.096 milliseconds (ms) long and repetition frequency of the pulse 
(i.e., the ping rate) is related to water depth. In shallow water, the 
highest pulse repetition frequency is about 20 pings per second. The 
scout vessel will use a Furuno 292 echosounder that operates at a 
frequency of 28 and 88 kHz. The highest ping rate in shallow water is 
12 pings per second.

Dates, Duration and Action Area

    As stated earlier, TGS plans to enter the U.S. Chukchi as early as 
July 15, 2013, and conduct its proposed 2D seismic surveys in both the 
U.S. Chukchi Sea and international waters through October 31, 2013. 
Seismic operations are anticipated to occur for about 35 days over a 
period of 45-60 days in U.S. waters and up to about 33 days in 
international waters. Operations in U.S. waters are expected to be 
complete no later than 5 October 2013. However, poor weather, ice 
conditions, equipment repair, etc., would likely delay or curtail 
operations. Thus, this extended period allows flexibility in proposed 
operational dates, contingent on such conditions. Specific proposed 
dates and durations of project activities are listed below in 
chronological order, but are contingent on weather and ice, etc.
    The seismic operations are proposed to occur in U.S. and 
international waters of the Chukchi Sea between about 70-77[deg] N and 
154-165[deg] W (Figure 1 of TGS' IHA application). Up to approximately 
6,088 km of seismic operations with the full sound source are planned 
to be conducted in U.S. waters as follows, which include 5,973 km of 
pre-plot lines plus approximately 115 km for 1-km run-in and 5-km run-
out between seismic lines. In addition, approximately 1,556 km with the 
single 60 in\3\ (or smaller) mitigation airgun are planned to be 
conducted during turns and transits between lines. Approximately 3,691 
km of seismic operations with the full seismic source as follows are 
planned to be conducted in international waters, which include 3,631 km 
of pre-plot lines plus about 60 km of 1-km run-in and 5-km run-out 
between pre-plot lines. In addition, approximately 812 km with the 
single 60 in3 (or smaller) mitigation airgun are planned to be 
conducted during turns and transits between seismic lines. Most of the 
total approximately 9,600 km of proposed seismic lines occur in water 
40-100 m deep (82% or 7,890 km), followed by waters >100 m deep (14% or 
1,320 km) and waters <40 m deep (4% or 390 km).

Description of Marine Mammals in the Area of the Specified Activity

    The marine mammal species under NMFS jurisdiction most likely to 
occur in the seismic survey area include eight cetacean species: beluga 
whale (Delphinapterus leucas), harbor porpoise (Phocoena phocoena), 
killer whale (Orcinus orca), bowhead whale (Balaena mysticetus), gray 
whale (Eschrichtius robustus), minke whale (Balaenoptera 
acutorostrata), fin whale (B. physalus), and humpback whale (Megaptera 
novaeangliae), and four pinniped species, ringed (Phoca hispida), 
spotted (P. largha), bearded (Erignathus barbatus), and ribbon seals 
(Histriophoca fasciata).

[[Page 35510]]

    The bowhead, fin, and humpback whales are listed as ``endangered'', 
and the ringed and bearded seals are listed as ``threatened'' under the 
Endangered Species Act (ESA) and as depleted under the MMPA. Certain 
stocks or populations of gray and beluga whales and spotted seals are 
also listed under the ESA, however, none of those stocks or populations 
occur in the proposed activity area.
    TGS' application contains information on the status, distribution, 
seasonal distribution, and abundance of each of the species under NMFS 
jurisdiction mentioned in this document. Please refer to the 
application for that information (see ADDRESSES). Additional 
information can also be found in the NMFS Stock Assessment Reports 
(SAR). The Alaska 2012 SAR is available at: https://www.nmfs.noaa.gov/pr/sars/pdf/ak2012.pdf.

Potential Effects of the Specified Activity on Marine Mammals

    Operating active acoustic sources such as airgun arrays, 
navigational sonars, and vessel activities has 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, 
and can be categorized as follows (based on Richardson et al. 1995):
(1) Behavioral Disturbance
    Marine mammals may behaviorally react to sound when exposed to 
anthropogenic noise. These behavioral reactions are often shown as: 
changing durations of surfacing and dives, number of blows per 
surfacing, or moving direction and/or speed; reduced/increased vocal 
activities; changing/cessation of certain behavioral activities (such 
as socializing or feeding); visible startle response or aggressive 
behavior (such as tail/fluke slapping or jaw clapping); avoidance of 
areas where noise sources are located; and/or flight responses (e.g., 
pinnipeds flushing into water from haulouts or rookeries).
    The biological significance of many of these behavioral 
disturbances is difficult to predict, especially if the detected 
disturbances appear minor. However, the consequences of behavioral 
modification could be expected to be biologically significant if the 
change affects growth, survival, and reproduction. Some of these 
potential significant behavioral modifications include:
     Drastic change in diving/surfacing patterns (such as those 
thought to be causing beaked whale stranding due to exposure to 
military mid-frequency tactical sonar);
     Habitat abandonment due to loss of desirable acoustic 
environment; and
     Cease feeding or social interaction.
    For example, at the Guerreo Negro Lagoon in Baja California, 
Mexico, which is one of the important breeding grounds for Pacific gray 
whales, shipping and dredging associated with a salt works may have 
induced gray whales to abandon the area through most of the 1960s 
(Bryant et al. 1984). After these activities stopped, the lagoon was 
reoccupied, first by single whales and later by cow-calf pairs.
    The onset of behavioral disturbance from anthropogenic noise 
depends on both external factors (characteristics of noise sources and 
their paths) and the receiving animals (hearing, motivation, 
experience, demography) and is also difficult to predict (Southall et 
al. 2007).
    Currently NMFS uses 160 dB re 1 [mu]Pa (rms) at received level for 
impulse noises (such as airgun pulses) as the threshold for the onset 
of marine mammal behavioral harassment.
    In addition, behavioral disturbance is also expressed as the change 
in vocal activities of animals. For example, there is one recent 
summary report indicating that calling fin whales distributed in one 
part of the North Atlantic went silent for an extended period starting 
soon after the onset of a seismic survey in the area (Clark and Gagnon 
2006). It is not clear from that preliminary paper whether the whales 
ceased calling because of masking, or whether this was a behavioral 
response not directly involving masking (i.e., important biological 
signals for marine mammals being ``masked'' by anthropogenic noise; see 
below). Also, bowhead whales in the Beaufort Sea may decrease their 
call rates in response to seismic operations, although movement out of 
the area might also have contributed to the lower call detection rate 
(Blackwell et al. 2009a; 2009b). Some of the changes in marine mammal 
vocal communication are thought to be used to compensate for acoustic 
masking resulting from increased anthropogenic noise (see below). For 
example, blue whales are found to increase call rates when exposed to 
seismic survey noise in the St. Lawrence Estuary (Di Iorio and Clark 
2009). The North Atlantic right whales (Eubalaena glacialis) exposed to 
high shipping noise increase call frequency (Parks et al. 2007) and 
intensity (Parks et al. 2010), while some humpback whales respond to 
low-frequency active sonar playbacks by increasing song length (Miller 
el al. 2000). These behavioral responses could also have adverse 
effects on marine mammals.
    Mysticetes: Baleen whales generally tend to avoid operating 
airguns, but avoidance radii are quite variable. Whales are often 
reported to show no overt reactions to airgun pulses at distances 
beyond a few kilometers, even though the airgun pulses remain well 
above ambient noise levels out to much longer distances (reviewed in 
Richardson et al. 1995; Gordon et al. 2004). However, studies done 
since the late 1990s of migrating humpback and migrating bowhead whales 
show reactions, including avoidance, that sometimes extend to greater 
distances than documented earlier. Therefore, it appears that 
behavioral disturbance can vary greatly depending on context, and not 
just received levels alone. Avoidance distances often exceed the 
distances at which boat-based observers can see whales, so observations 
from the source vessel can be biased. Observations over broader areas 
may be needed to determine the range of potential effects of some 
large-source seismic surveys where effects on cetaceans may extend to 
considerable distances (Richardson et al. 1999; Moore and Angliss 
2006). Longer-range observations, when required, can sometimes be 
obtained via systematic aerial surveys or aircraft-based observations 
of behavior (e.g., Richardson et al. 1986, 1999; Miller et al. 1999, 
2005; Yazvenko et al. 2007a, 2007b) or by use of observers on one or 
more support vessels operating in coordination with the seismic vessel 
(e.g., Smultea et al. 2004; Johnson et al. 2007). However, the presence 
of other vessels near the source vessel can, at least at times, reduce 
sightability of cetaceans from the source vessel (Beland et al. 2009), 
thus complicating interpretation of sighting data.
    Some baleen whales show considerable tolerance of seismic pulses. 
However, when the pulses are strong enough, avoidance or other 
behavioral changes become evident. Because the responses become less 
obvious with diminishing received sound level, it has been difficult to 
determine the maximum distance (or minimum received sound level) at 
which reactions to seismic activity become evident and, hence, how many 
whales are affected.

[[Page 35511]]

    Studies of gray, bowhead, and humpback whales have determined that 
received levels of pulses in the 160-170 dB re 1 [mu]Pa (rms) range 
seem to cause obvious avoidance behavior in a substantial fraction of 
the animals exposed (McCauley et al. 1998, 1999, 2000). In many areas, 
seismic pulses diminish to these levels at distances ranging from 4-15 
km from the source. A substantial proportion of the baleen whales 
within such distances may show avoidance or other strong disturbance 
reactions to the operating airgun array. Some extreme examples 
including migrating bowhead whales avoiding considerably larger 
distances (20-30 km) and lower received sound levels (120-130 dB re 1 
[mu]Pa (rms)) when exposed to airguns from seismic surveys. Also, even 
in cases where there is no conspicuous avoidance or change in activity 
upon exposure to sound pulses from distant seismic operations, there 
are sometimes subtle changes in behavior (e.g., surfacing-respiration-
dive cycles) that are only evident through detailed statistical 
analysis (e.g., Richardson et al. 1986; Gailey et al. 2007).
    Data on short-term reactions by cetaceans to impulsive noises are 
not necessarily indicative of long-term or biologically significant 
effects. It is not known whether impulsive sounds affect reproductive 
rate or distribution and habitat use in subsequent days or years. 
However, gray whales have continued to migrate annually along the west 
coast of North America despite intermittent seismic exploration (and 
much ship traffic) in that area for decades (Appendix A in Malme et al. 
1984; Richardson et al. 1995), and there has been a substantial 
increase in the population over recent decades (Allen and Angliss 
2010). The western Pacific gray whale population did not seem affected 
by a seismic survey in its feeding ground during a prior year (Johnson 
et al. 2007). Similarly, bowhead whales have continued to travel to the 
eastern Beaufort Sea each summer despite seismic exploration in their 
summer and autumn range for many years (Richardson et al. 1987), and 
their numbers have increased notably (Allen and Angliss 2010). Bowheads 
also have been observed over periods of days or weeks in areas 
ensonified repeatedly by seismic pulses (Richardson et al. 1987; Harris 
et al. 2007). However, it is generally not known whether the same 
individual bowheads were involved in these repeated observations 
(within and between years) in strongly ensonified areas.
    Odontocete: Relatively little systematic information is available 
about reactions of toothed whales to airgun pulses. A few studies 
similar to the more extensive baleen whale/seismic pulse work 
summarized above have been reported for toothed whales. However, there 
are recent systematic data on sperm whales (e.g., Gordon et al. 2006; 
Madsen et al. 2006; Winsor and Mate 2006; Jochens et al. 2008; Miller 
et al. 2009) and beluga whales (e.g., Miller et al. 2005). There is 
also an increasing amount of information about responses of various 
odontocetes to seismic surveys based on monitoring studies (e.g., Stone 
2003; Smultea et al. 2004; Moulton and Miller 2005; Holst et al. 2006; 
Stone and Tasker 2006; Potter et al. 2007; Hauser et al. 2008; Holst 
and Smultea 2008; Weir 2008; Barkaszi et al. 2009; Richardson et al. 
2009).
    Dolphins and porpoises are often seen by observers on active 
seismic vessels, occasionally at close distances (e.g., bow riding). 
Marine mammal monitoring data during seismic surveys often show that 
animal detection rates drop during the firing of seismic airguns, 
indicating that animals may be avoiding the vicinity of the seismic 
area (Smultea et al. 2004; Holst et al. 2006; Hauser et al. 2008; Holst 
and Smultea 2008; Richardson et al. 2009). Also, belugas summering in 
the Canadian Beaufort Sea showed larger-scale avoidance, tending to 
avoid waters out to 10-20 km from operating seismic vessels (Miller et 
al. 2005). In contrast, recent studies show little evidence of 
conspicuous reactions by sperm whales to airgun pulses, contrary to 
earlier indications (e.g., Gordon et al. 2006; Stone and Tasker 2006; 
Winsor and Mate 2006; Jochens et al. 2008), except the lower buzz 
(echolocation signals) rates that were detected during exposure of 
airgun pulses (Miller et al. 2009).
    There are almost no specific data on responses of beaked whales to 
seismic surveys, but it is likely that most if not all species show 
strong avoidance. There is increasing evidence that some beaked whales 
may strand after exposure to strong noise from tactical military mid-
frequency sonars. Whether they ever do so in response to seismic survey 
noise is unknown. Northern bottlenose whales seem to continue to call 
when exposed to pulses from distant seismic vessels.
    For delphinids, and possibly the Dall's porpoise, the available 
data suggest that a >=170 dB re 1 [mu]Pa (rms) disturbance criterion 
(rather than >=160 dB) would be appropriate. With a medium-to-large 
airgun array, received levels typically diminish to 170 dB within 1-4 
km, whereas levels typically remain above 160 dB out to 4-15 km (e.g., 
Tolstoy et al. 2009). Reaction distances for delphinids are more 
consistent with the typical 170 dB re 1 [mu]Pa (rms) distances. Stone 
(2003) and Stone and Tasker (2006) reported that all small odontocetes 
(including killer whales) observed during seismic surveys in UK waters 
remained significantly further from the source during periods of 
shooting on surveys with large volume airgun arrays than during periods 
without airgun shooting.
    Due to their relatively higher frequency hearing ranges when 
compared to mysticetes, odontocetes may have stronger responses to mid- 
and high-frequency sources such as sub-bottom profilers, side scan 
sonar, and echo sounders than mysticetes (Richardson et al. 1995; 
Southall et al. 2007).
    Pinnipeds: Few studies of the reactions of pinnipeds to noise from 
open-water seismic exploration have been published (for review of the 
early literature, see Richardson et al. 1995). However, pinnipeds have 
been observed during a number of seismic monitoring studies. Monitoring 
in the Beaufort Sea during 1996-2002 provided a substantial amount of 
information on avoidance responses (or lack thereof) and associated 
behavior. Additional monitoring of that type has been done in the 
Beaufort and Chukchi Seas in 2006-2009. Pinnipeds exposed to seismic 
surveys have also been observed during seismic surveys along the U.S. 
west coast. Also, there are data on the reactions of pinnipeds to 
various other related types of impulsive sounds.
    Early observations provided considerable evidence that pinnipeds 
are often quite tolerant of strong pulsed sounds. During seismic 
exploration off Nova Scotia, gray seals exposed to noise from airguns 
and linear explosive charges reportedly did not react strongly (J. 
Parsons in Greene et al. 1985). An airgun caused an initial startle 
reaction among South African fur seals but was ineffective in scaring 
them away from fishing gear. Pinnipeds in both water and air sometimes 
tolerate strong noise pulses from non-explosive and explosive scaring 
devices, especially if attracted to the area for feeding or 
reproduction (Mate and Harvey 1987; Reeves et al. 1996). Thus, 
pinnipeds are expected to be rather tolerant of, or to habituate to, 
repeated underwater sounds from distant seismic sources, at least when 
the animals are strongly attracted to the area.
    In summary, visual monitoring from seismic vessels has shown only 
slight (if any) avoidance of airguns by pinnipeds, and only slight (if 
any) changes in

[[Page 35512]]

behavior. These studies show that many pinnipeds do not avoid the area 
within a few hundred meters of an operating airgun array. However, 
based on the studies with large sample size, or observations from a 
separate monitoring vessel, or radio telemetry, it is apparent that 
some phocid seals do show localized avoidance of operating airguns. The 
limited nature of this tendency for avoidance is a concern. It suggests 
that one cannot rely on pinnipeds to move away, or to move very far 
away, before received levels of sound from an approaching seismic 
survey vessel approach those that may cause hearing impairment.
(2) Masking
    Masking occurs when noise and signals (that animal utilizes) 
overlap at both spectral and temporal scales. Chronic exposure to 
elevated sound levels could cause masking at particular frequencies for 
marine mammals, which utilize sound for important biological functions. 
Masking can interfere with detection of acoustic signals used for 
orientation, communication, finding prey, and avoiding predators. 
Marine mammals that experience severe (high intensity and extended 
duration) acoustic masking could potentially suffer reduced fitness, 
which could lead to adverse effects on survival and reproduction.
    For the airgun noise generated from the proposed marine seismic 
survey, these are low frequency (under 1 kHz) pulses with extremely 
short durations (in the scale of milliseconds). Lower frequency man-
made noises are more likely to affect detection of communication calls 
and other potentially important natural sounds such as surf and prey 
noise. There is little concern regarding masking due to the brief 
duration of these pulses and relatively longer silence between airgun 
shots (9-12 seconds) near the noise source, however, at long distances 
(over tens of kilometers away) in deep water, due to multipath 
propagation and reverberation, the durations of airgun pulses can be 
``stretched'' to seconds with long decays (Madsen et al. 2006; Clark 
and Gagnon 2006). Therefore it could affect communication signals used 
by low frequency mysticetes when they occur near the noise band and 
thus reduce the communication space of animals (e.g., Clark et al. 
2009a, 2009b) and affect their vocal behavior (e.g., Foote et al. 2004; 
Holt et al. 2009). Further, in areas of shallow water, multipath 
propagation of airgun pulses could be more profound, thus affecting 
communication signals from marine mammals even at close distances. 
Average ambient noise in areas where received seismic noises are heard 
can be elevated. At long distances, however, the intensity of the noise 
is greatly reduced. Nevertheless, partial informational and energetic 
masking of different degrees could affect signal receiving in some 
marine mammals within the ensonified areas. Additional research is 
needed to further address these effects.
    Although masking effects of pulsed sounds on marine mammal calls 
and other natural sounds are expected to be limited, there are few 
specific studies on this. Some whales continue calling in the presence 
of seismic pulses and whale calls often can be heard between the 
seismic pulses (e.g., Richardson et al. 1986; McDonald et al. 1995; 
Greene et al. 1999a, 1999b; Nieukirk et al. 2004; Smultea et al. 2004; 
Holst et al. 2005a, 2005b, 2006; Dunn and Hernandez 2009).
    Among the odontocetes, there has been one report that sperm whales 
ceased calling when exposed to pulses from a very distant seismic ship 
(Bowles et al. 1994). However, more recent studies of sperm whales 
found that they continued calling in the presence of seismic pulses 
(Madsen et al. 2002; Tyack et al. 2003; Smultea et al. 2004; Holst et 
al. 2006; Jochens et al. 2008). Madsen et al. (2006) noted that airgun 
sounds would not be expected to mask sperm whale calls given the 
intermittent nature of airgun pulses. Dolphins and porpoises are also 
commonly heard calling while airguns are operating (Gordon et al. 2004; 
Smultea et al. 2004; Holst et al. 2005a, 2005b; Potter et al. 2007). 
Masking effects of seismic pulses are expected to be negligible in the 
case of the smaller odontocetes, given the intermittent nature of 
seismic pulses plus the fact that sounds important to them are 
predominantly at much higher frequencies than are the dominant 
components of airgun sounds.
    Pinnipeds have best hearing sensitivity and/or produce most of 
their sounds at frequencies higher than the dominant components of 
airgun sound, but there is some overlap in the frequencies of the 
airgun pulses and the calls. However, the intermittent nature of airgun 
pulses presumably reduces the potential for masking.
    Marine mammals are thought to be able to compensate for masking by 
adjusting their acoustic behavior such as shifting call frequencies, 
and increasing call volume and vocalization rates, as discussed earlier 
(e.g., Miller et al. 2000; Parks et al. 2007; Di Iorio and Clark 2009; 
Parks et al. 2010); the biological significance of these modifications 
is still unknown.
(3) Hearing Impairment
    Marine mammals exposed to high intensity sound repeatedly or for 
prolonged periods can experience hearing threshold shift (TS), which is 
the loss of hearing sensitivity at certain frequency ranges (Kastak et 
al. 1999; Schlundt et al. 2000; Finneran et al. 2002; 2005). TS can be 
permanent (PTS), in which case the loss of hearing sensitivity is 
unrecoverable, or temporary (TTS), in which case the animal's hearing 
threshold will recover over time (Southall et al. 2007). Marine mammals 
that experience TTS or PTS will have reduced sensitivity at the 
frequency band of the TS, which may affect their capability of 
communication, orientation, or prey detection. The degree of TS depends 
on the intensity of the received levels the animal is exposed to, and 
the frequency at which TS occurs depends on the frequency of the 
received noise. It has been shown that in most cases, TS occurs at the 
frequencies approximately one-octave above that of the received noise. 
Repeated noise exposure that leads to TTS could cause PTS. For 
transient sounds, the sound level necessary to cause TTS is inversely 
related to the duration of the sound.
TTS
    TTS is the mildest form of hearing impairment that can occur during 
exposure to a strong sound (Kryter 1985). While experiencing TTS, the 
hearing threshold rises and a sound must be stronger in order to be 
heard. It is a temporary phenomenon, and (especially when mild) is not 
considered to represent physical damage or ``injury'' (Southall et al. 
2007). Rather, the onset of TTS is an indicator that, if the animal is 
exposed to higher levels of that sound, physical damage is ultimately a 
possibility.
    The magnitude of TTS depends on the level and duration of noise 
exposure, and to some degree on frequency, among other considerations 
(Kryter 1985; Richardson et al. 1995; Southall et al. 2007). For sound 
exposures at or somewhat above the TTS threshold, hearing sensitivity 
recovers rapidly after exposure to the noise ends. In terrestrial 
mammals, TTS can last from minutes or hours to (in cases of strong TTS) 
days. Only a few data have been obtained on sound levels and durations 
necessary to elicit mild TTS in marine mammals (none in mysticetes), 
and none of the published data concern TTS elicited by exposure to 
multiple pulses of sound during operational seismic surveys (Southall 
et al. 2007).

[[Page 35513]]

    For toothed whales, experiments on a bottlenose dolphin (Tursiops 
truncates) and beluga whale showed that exposure to a single watergun 
impulse at a received level of 207 kPa (or 30 psi) peak-to-peak (p-p), 
which is equivalent to 228 dB re 1 [mu]Pa (p-p), resulted in a 7 and 6 
dB TTS in the beluga whale at 0.4 and 30 kHz, respectively. Thresholds 
returned to within 2 dB of the pre-exposure level within 4 minutes of 
the exposure (Finneran et al. 2002). No TTS was observed in the 
bottlenose dolphin.
    Finneran et al. (2005) further examined the effects of tone 
duration on TTS in bottlenose dolphins. Bottlenose dolphins were 
exposed to 3 kHz tones (non-impulsive) for periods of 1, 2, 4 or 8 
seconds (s), with hearing tested at 4.5 kHz. For 1-s exposures, TTS 
occurred with SELs of 197 dB, and for exposures >1 s, SEL >195 dB 
resulted in TTS (SEL is equivalent to energy flux, in dB re 1 
[mu]Pa\2\-s). At an SEL of 195 dB, the mean TTS (4 min after exposure) 
was 2.8 dB. Finneran et al. (2005) suggested that an SEL of 195 dB is 
the likely threshold for the onset of TTS in dolphins and belugas 
exposed to tones of durations 1--8 s (i.e., TTS onset occurs at a near-
constant SEL, independent of exposure duration). That implies that, at 
least for non-impulsive tones, a doubling of exposure time results in a 
3 dB lower TTS threshold.
    However, the assumption that, in marine mammals, the occurrence and 
magnitude of TTS is a function of cumulative acoustic energy (SEL) is 
probably an oversimplification. Kastak et al. (2005) reported 
preliminary evidence from pinnipeds that, for prolonged non-impulse 
noise, higher SELs were required to elicit a given TTS if exposure 
duration was short than if it was longer, i.e., the results were not 
fully consistent with an equal-energy model to predict TTS onset. 
Mooney et al. (2009a) showed this in a bottlenose dolphin exposed to 
octave-band non-impulse noise ranging from 4 to 8 kHz at SPLs of 130 to 
178 dB re 1 [mu]Pa for periods of 1.88 to 30 minutes (min). Higher SELs 
were required to induce a given TTS if exposure duration was short than 
if it was longer. Exposure of the aforementioned bottlenose dolphin to 
a sequence of brief sonar signals showed that, with those brief (but 
non-impulse) sounds, the received energy (SEL) necessary to elicit TTS 
was higher than was the case with exposure to the more prolonged 
octave-band noise (Mooney et al. 2009b). Those authors concluded that, 
when using (non-impulse) acoustic signals of duration ~0.5 s, SEL must 
be at least 210-214 dB re 1 [mu]Pa\2\-s to induce TTS in the bottlenose 
dolphin. The most recent studies conducted by Finneran et al. also 
support the notion that exposure duration has a more significant 
influence compared to SPL as the duration increases, and that TTS 
growth data are better represented as functions of SPL and duration 
rather than SEL alone (Finneran et al. 2010a, 2010b). In addition, 
Finneran et al. (2010b) conclude that when animals are exposed to 
intermittent noises, there is recovery of hearing during the quiet 
intervals between exposures through the accumulation of TTS across 
multiple exposures. Such findings suggest that when exposed to multiple 
seismic pulses, partial hearing recovery also occurs during the seismic 
pulse intervals.
    For baleen whales, there are no data, direct or indirect, on levels 
or properties of sound that are required to induce TTS. The frequencies 
to which baleen whales are most sensitive are lower than those to which 
odontocetes are most sensitive, and natural ambient noise levels at 
those low frequencies tend to be higher (Urick 1983). As a result, 
auditory thresholds of baleen whales within their frequency band of 
best hearing are believed to be higher (less sensitive) than are those 
of odontocetes at their best frequencies (Clark and Ellison 2004). From 
this, it is suspected that received levels causing TTS onset may also 
be higher in baleen whales. However, no cases of TTS are expected given 
the small size of the airguns proposed to be used and the strong 
likelihood that baleen whales (especially migrating bowheads) would 
avoid the approaching airguns (or vessel) before being exposed to 
levels high enough for there to be any possibility of TTS.
    In pinnipeds, TTS thresholds associated with exposure to brief 
pulses (single or multiple) of underwater sound have not been measured. 
Initial evidence from prolonged exposures suggested that some pinnipeds 
may incur TTS at somewhat lower received levels than do small 
odontocetes exposed for similar durations (Kastak et al. 1999; 2005). 
However, more recent indications are that TTS onset in the most 
sensitive pinniped species studied (harbor seal, which is closely 
related to the ringed seal) may occur at a similar SEL as in 
odontocetes (Kastak et al. 2004).
    Most cetaceans show some degree of avoidance of seismic vessels 
operating an airgun array (see above). It is unlikely that these 
cetaceans would be exposed to airgun pulses at a sufficiently high 
level for a sufficiently long period to cause more than mild TTS, given 
the relative movement of the vessel and the marine mammal. TTS would be 
more likely in any odontocetes that bow- or wake-ride or otherwise 
linger near the airguns. However, while bow- or wake-riding, 
odontocetes would be at the surface and thus not exposed to strong 
sound pulses given the pressure release and Lloyd Mirror effects at the 
surface. But if bow- or wake-riding animals were to dive intermittently 
near airguns, they would be exposed to strong sound pulses, possibly 
repeatedly.
    If some cetaceans did incur mild or moderate TTS through exposure 
to airgun sounds in this manner, this would very likely be a temporary 
and reversible phenomenon. However, even a temporary reduction in 
hearing sensitivity could be deleterious in the event that, during that 
period of reduced sensitivity, a marine mammal needed its full hearing 
sensitivity to detect approaching predators, or for some other reason.
    Some pinnipeds show avoidance reactions to airguns, but their 
avoidance reactions are generally not as strong or consistent as those 
of cetaceans. Pinnipeds occasionally seem to be attracted to operating 
seismic vessels. There are no specific data on TTS thresholds of 
pinnipeds exposed to single or multiple low-frequency pulses. However, 
given the indirect indications of a lower TTS threshold for the harbor 
seal than for odontocetes exposed to impulse sound (see above), it is 
possible that some pinnipeds close to a large airgun array could incur 
TTS.
    NMFS currently typically includes mitigation requirements to ensure 
that cetaceans and pinnipeds are not exposed to pulsed underwater noise 
at received levels exceeding, respectively, 180 and 190 dB re 1 
[micro]Pa (rms). The 180/190 dB acoustic criteria were taken from 
recommendations by an expert panel of the High Energy Seismic Survey 
(HESS) Team that performed an assessment on noise impacts by seismic 
airguns to marine mammals in 1997, although the HESS Team recommended a 
180-dB limit for pinnipeds in California (HESS 1999). The 180 and 190 
dB re 1 [mu]Pa (rms) levels have not been considered to be the levels 
above which TTS might occur. Rather, they were the received levels 
above which, in the view of a panel of bioacoustics specialists 
convened by NMFS before TTS measurements for marine mammals started to 
become available, one could not be certain that there would be no 
injurious effects, auditory or otherwise, to marine mammals. As 
summarized above, data that are now available imply that TTS is 
unlikely to occur in various odontocetes (and probably mysticetes as

[[Page 35514]]

well) unless they are exposed to a sequence of several airgun pulses 
stronger than 190 dB re 1 [mu]Pa (rms). On the other hand, for the 
harbor seal, harbor porpoise, and perhaps some other species, TTS may 
occur upon exposure to one or more airgun pulses whose received level 
equals the NMFS ``do not exceed'' value of 190 dB re 1 [mu]Pa (rms). 
That criterion corresponds to a single-pulse SEL of 175-180 dB re 1 
[mu]Pa\2\-s in typical conditions, whereas TTS is suspected to be 
possible in harbor seals and harbor porpoises with a cumulative SEL of 
~171 and ~164 dB re 1 [mu]Pa\2\-s, respectively.
    It has been shown that most large whales and many smaller 
odontocetes (especially the harbor porpoise) show at least localized 
avoidance of ships and/or seismic operations. Even when avoidance is 
limited to the area within a few hundred meters of an airgun array, 
that should usually be sufficient to avoid TTS based on what is 
currently known about thresholds for TTS onset in cetaceans. In 
addition, ramping up airgun arrays, which is standard operational 
protocol for many seismic operators, may allow cetaceans near the 
airguns at the time of startup (if the sounds are aversive) to move 
away from the seismic source and to avoid being exposed to the full 
acoustic output of the airgun array. Thus, most baleen whales likely 
will not be exposed to high levels of airgun sounds provided the ramp-
up procedure is applied. Likewise, many odontocetes close to the 
trackline are likely to move away before the sounds from an approaching 
seismic vessel become sufficiently strong for there to be any potential 
for TTS or other hearing impairment. Hence, there is little potential 
for baleen whales or odontocetes that show avoidance of ships or 
airguns to be close enough to an airgun array to experience TTS. 
Nevertheless, even if marine mammals were to experience TTS, the 
magnitude of the TTS is expected to be mild and brief, only in a few 
decibels for minutes.
PTS
    When PTS occurs, there is physical damage to the sound receptors in 
the ear. In some cases, there can be total or partial deafness, whereas 
in other cases, the animal has an impaired ability to hear sounds in 
specific frequency ranges (Kryter 1985). Physical damage to a mammal's 
hearing apparatus can occur if it is exposed to sound impulses that 
have very high peak pressures, especially if they have very short rise 
times. (Rise time is the interval required for sound pressure to 
increase from the baseline pressure to peak pressure.)
    There is no specific evidence that exposure to pulses of airgun 
sound can cause PTS in any marine mammal, even with large arrays of 
airguns. However, given the likelihood that some mammals close to an 
airgun array might incur at least mild TTS (see above), there has been 
further speculation about the possibility that some individuals 
occurring very close to airguns might incur PTS (e.g., Richardson et 
al. 1995; Gedamke et al. 2008). Single or occasional occurrences of 
mild TTS are not indicative of permanent auditory damage, but repeated 
or (in some cases) single exposures to a level well above that causing 
TTS onset might elicit PTS.
    Relationships between TTS and PTS thresholds have not been studied 
in marine mammals, but are assumed to be similar to those in humans and 
other terrestrial mammals (Southall et al. 2007). Based on data from 
terrestrial mammals, a precautionary assumption is that the PTS 
threshold for impulse sounds (such as airgun pulses as received close 
to the source) is at least 6 dB higher than the TTS threshold on a 
peak-pressure basis, and probably >6 dB higher (Southall et al. 2007). 
The low-to-moderate levels of TTS that have been induced in captive 
odontocetes and pinnipeds during controlled studies of TTS have been 
confirmed to be temporary, with no measurable residual PTS (Kastak et 
al. 1999; Schlundt et al. 2000; Finneran et al. 2002; 2005; Nachtigall 
et al. 2003; 2004). However, very prolonged exposure to sound strong 
enough to elicit TTS, or shorter-term exposure to sound levels well 
above the TTS threshold, can cause PTS, at least in terrestrial mammals 
(Kryter 1985). In terrestrial mammals, the received sound level from a 
single non-impulsive sound exposure must be far above the TTS threshold 
for any risk of permanent hearing damage (Kryter 1994; Richardson et 
al. 1995; Southall et al. 2007). However, there is special concern 
about strong sounds whose pulses have very rapid rise times. In 
terrestrial mammals, there are situations when pulses with rapid rise 
times (e.g., from explosions) can result in PTS even though their peak 
levels are only a few dB higher than the level causing slight TTS. The 
rise time of airgun pulses is fast, but not as fast as that of an 
explosion.
    Some factors that contribute to onset of PTS, at least in 
terrestrial mammals, are as follows:
     exposure to a single very intense sound,
     fast rise time from baseline to peak pressure,
     repetitive exposure to intense sounds that individually 
cause TTS but not PTS, and
     recurrent ear infections or (in captive animals) exposure 
to certain drugs.
    Cavanagh (2000) reviewed the thresholds used to define TTS and PTS. 
Based on this review and SACLANT (1998), it is reasonable to assume 
that PTS might occur at a received sound level 20 dB or more above that 
inducing mild TTS. However, for PTS to occur at a received level only 
20 dB above the TTS threshold, the animal probably would have to be 
exposed to a strong sound for an extended period, or to a strong sound 
with a rather rapid rise time.
    More recently, Southall et al. (2007) estimated that received 
levels would need to exceed the TTS threshold by at least 15 dB, on an 
SEL basis, for there to be risk of PTS. Thus, for cetaceans exposed to 
a sequence of sound pulses, they estimate that the PTS threshold might 
be an M-weighted SEL (for the sequence of received pulses) of ~198 dB 
re 1 [mu]Pa\2\-s. Additional assumptions had to be made to derive a 
corresponding estimate for pinnipeds, as the only available data on 
TTS-thresholds in pinnipeds pertained to nonimpulse sound (see above). 
Southall et al. (2007) estimated that the PTS threshold could be a 
cumulative SEL of ~186 dB re 1 [mu]Pa\2\-s in the case of a harbor seal 
exposed to impulse sound. The PTS threshold for the California sea lion 
and northern elephant seal would probably be higher given the higher 
TTS thresholds in those species. Southall et al. (2007) also note that, 
regardless of the SEL, there is concern about the possibility of PTS if 
a cetacean or pinniped received one or more pulses with peak pressure 
exceeding 230 or 218 dB re 1 [mu]Pa, respectively. Thus, PTS might be 
expected upon exposure of cetaceans to either SEL >=198 dB re 1 
[mu]Pa\2\-s or peak pressure >=230 dB re 1 [mu]Pa. Corresponding 
proposed dual criteria for pinnipeds (at least harbor seals) are >=186 
dB SEL and >= 218 dB peak pressure (Southall et al. 2007). These 
estimates are all first approximations, given the limited underlying 
data, assumptions, species differences, and evidence that the ``equal 
energy'' model may not be entirely correct.
    Sound impulse duration, peak amplitude, rise time, number of 
pulses, and inter-pulse interval are the main factors thought to 
determine the onset and extent of PTS. Ketten (1994) has noted that the 
criteria for differentiating the sound pressure levels that result in 
PTS (or TTS) are location and species

[[Page 35515]]

specific. PTS effects may also be influenced strongly by the health of 
the receiver's ear.
    As described above for TTS, in estimating the amount of sound 
energy required to elicit the onset of TTS (and PTS), it is assumed 
that the auditory effect of a given cumulative SEL from a series of 
pulses is the same as if that amount of sound energy were received as a 
single strong sound. There are no data from marine mammals concerning 
the occurrence or magnitude of a potential partial recovery effect 
between pulses. In deriving the estimates of PTS (and TTS) thresholds 
quoted here, Southall et al. (2007) made the precautionary assumption 
that no recovery would occur between pulses.
    It is unlikely that an odontocete would remain close enough to a 
large airgun array for sufficiently long to incur PTS. There is some 
concern about bowriding odontocetes, but for animals at or near the 
surface, auditory effects are reduced by Lloyd's mirror and surface 
release effects. The presence of the vessel between the airgun array 
and bow-riding odontocetes could also, in some but probably not all 
cases, reduce the levels received by bow-riding animals (e.g., Gabriele 
and Kipple 2009). The TTS (and thus PTS) thresholds of baleen whales 
are unknown but, as an interim measure, assumed to be no lower than 
those of odontocetes. Also, baleen whales generally avoid the immediate 
area around operating seismic vessels, so it is unlikely that a baleen 
whale could incur PTS from exposure to airgun pulses. The TTS (and thus 
PTS) thresholds of some pinnipeds (e.g., harbor seal) as well as the 
harbor porpoise may be lower (Kastak et al. 2005; Southall et al. 2007; 
Lucke et al. 2009). If so, TTS and potentially PTS may extend to a 
somewhat greater distance for those animals. Again, Lloyd's mirror and 
surface release effects will ameliorate the effects for animals at or 
near the surface.
(4) Non-Auditory Physical Effects
    Non-auditory physical effects might occur in marine mammals exposed 
to strong underwater pulsed sound. Possible types of non-auditory 
physiological effects or injuries that theoretically might occur in 
mammals close to a strong sound source include neurological effects, 
bubble formation, and other types of organ or tissue damage. Some 
marine mammal species (i.e., beaked whales) may be especially 
susceptible to injury and/or stranding when exposed to intense sounds. 
However, there is no definitive evidence that any of these effects 
occur even for marine mammals in close proximity to large arrays of 
airguns, and beaked whales do not occur in the proposed project area. 
In addition, marine mammals that show behavioral avoidance of seismic 
vessels, including most baleen whales, some odontocetes (including 
belugas), and some pinnipeds, are especially unlikely to incur non-
auditory impairment or other physical effects.
    Therefore, it is unlikely that such effects would occur during TGS' 
proposed seismic surveys given the brief duration of exposure, the 
small sound sources, and the planned monitoring and mitigation measures 
described later in this document.
    Additional non-auditory effects include elevated levels of stress 
response (Wright et al. 2007; Wright and Highfill 2007). Although not 
many studies have been done on noise-induced stress in marine mammals, 
extrapolation of information regarding stress responses in other 
species seems applicable because the responses are highly consistent 
among all species in which they have been examined to date (Wright et 
al. 2007). Therefore, it is reasonable to conclude that noise acts as a 
stressor to marine mammals. Furthermore, given that marine mammals will 
likely respond in a manner consistent with other species studied, 
repeated and prolonged exposures to stressors (including or induced by 
noise) could potentially be problematic for marine mammals of all ages. 
Wright et al. (2007) state that a range of issues may arise from an 
extended stress response including, but not limited to, suppression of 
reproduction (physiologically and behaviorally), accelerated aging and 
sickness-like symptoms. However, as mentioned above, TGS' proposed 
activity is not expected to result in these severe effects due to the 
nature of the potential sound exposure.
(5) Stranding and Mortality
    Marine mammals close to underwater detonations can be killed or 
severely injured, and the auditory organs are especially susceptible to 
injury (Ketten et al. 1993; Ketten 1995). Airgun pulses are less 
energetic and their peak amplitudes have slower rise times, while 
stranding and mortality events would include other energy sources 
(acoustical or shock wave) far beyond just seismic airguns. To date, 
there is no evidence that serious injury, death, or stranding by marine 
mammals can occur from exposure to airgun pulses, even in the case of 
large airgun arrays.
    However, in numerous past IHA notices for seismic surveys, 
commenters have referenced two stranding events allegedly associated 
with seismic activities, one off Baja California and a second off 
Brazil. NMFS has addressed this concern several times, and, without new 
information, does not believe that this issue warrants further 
discussion. For information relevant to strandings of marine mammals, 
readers are encouraged to review NMFS' response to comments on this 
matter found in 69 FR 74906 (December 14, 2004), 71 FR 43112 (July 31, 
2006), 71 FR 50027 (August 24, 2006), and 71 FR 49418 (August 23, 
2006).
    It should be noted that strandings related to sound exposure have 
not been recorded for marine mammal species in the Chukchi or Beaufort 
seas. NMFS notes that in the Beaufort and Chukchi seas, aerial surveys 
have been conducted by BOEM (previously MMS) and industry during 
periods of industrial activity (and by BOEM during times with no 
activity). No strandings or marine mammals in distress have been 
observed during these surveys and none have been reported by North 
Slope Borough inhabitants. In addition, there are very few instances 
that seismic surveys in general have been linked to marine mammal 
strandings, other than those mentioned above. As a result, NMFS does 
not expect any marine mammals will incur serious injury or mortality in 
the Arctic Ocean or strand as a result of the proposed marine survey.

Potential Effects of Sonar Signals

    Industrial standard navigational sonars would be used during TGS' 
proposed 2D seismic surveys program for navigation safety. Source 
characteristics of the representative generic equipment are discussed 
in the ``Description of Specific Activity'' section above. In general, 
the potential effects of this equipment on marine mammals are similar 
to those from the airgun, except the magnitude of the impacts is 
expected to be much less due to the lower intensity, higher 
frequencies, and with downward narrow beam patterns. In some cases, due 
to the fact that the operating frequencies of some of this equipment 
(e.g., Kongsberg EA600 with frequencies up to 200 kHz) are above the 
hearing ranges of marine mammals, they are not expected to have any 
impacts to marine mammals.

Vessel Sounds

    In addition to the noise generated from seismic airguns and active 
sonar systems, two vessels would be involved in the operations, 
including a source vessel and a support vessel that provides marine 
mammal monitoring

[[Page 35516]]

and logistic support. Sounds from boats and vessels have been reported 
extensively (Greene and Moore 1995; Blackwell and Greene 2002; 2005; 
2006). Numerous measurements of underwater vessel sound have been 
performed in support of recent industry activity in the Chukchi and 
Beaufort Seas. Results of these measurements were reported in various 
90-day and comprehensive reports since 2007 (e.g., Aerts et al. 2008; 
Hauser et al. 2008; Brueggeman 2009; Ireland et al. 2009; O'Neill and 
McCrodan 2011; Chorney et al. 2011; McPherson and Warner 2012). For 
example, Garner and Hannay (2009) estimated sound pressure levels of 
100 dB at distances ranging from approximately 1.5 to 2.3 mi (2.4 to 
3.7 km) from various types of barges. MacDonald et al. (2008) estimated 
higher underwater SPLs from the seismic vessel Gilavar of 120 dB at 
approximately 13 mi (21 km) from the source, although the sound level 
was only 150 dB at 85 ft (26 m) from the vessel. Compared to airgun 
pulses, underwater sound from vessels is generally at relatively low 
frequencies.
    The primary sources of sounds from all vessel classes are propeller 
cavitation, propeller singing, and propulsion or other machinery. 
Propeller cavitation is usually the dominant noise source for vessels 
(Ross 1976). Propeller cavitation and singing are produced outside the 
hull, whereas propulsion or other machinery noise originates inside the 
hull. There are additional sounds produced by vessel activity, such as 
pumps, generators, flow noise from water passing over the hull, and 
bubbles breaking in the wake. Source levels from various vessels would 
be empirically measured before the start of the seismic surveys.

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 vessels operating in the area. However, other potential impacts to 
the surrounding habitat from physical disturbance are also possible.
    With regard to fish as a prey source for cetaceans and pinnipeds, 
fish are known to hear and react to sounds and to use sound to 
communicate (Tavolga et al. 1981) and possibly avoid predators (Wilson 
and Dill 2002). Experiments have shown that fish can sense both the 
strength and direction of sound (Hawkins 1981). Primary factors 
determining whether a fish can sense a sound signal, and potentially 
react to it, are the frequency of the signal and the strength of the 
signal in relation to the natural background noise level.
    The level of sound at which a fish will react or alter its behavior 
is usually well above the detection level. Fish have been found to 
react to sounds when the sound level increased to about 20 dB above the 
detection level of 120 dB (Ona 1988); however, the response threshold 
can depend on the time of year and the fish's physiological condition 
(Engas et al. 1993). In general, fish react more strongly to pulses of 
sound rather than non-pulse signals (such as noise from vessels) 
(Blaxter et al. 1981), and a quicker alarm response is elicited when 
the sound signal intensity rises rapidly compared to sound rising more 
slowly to the same level.
    Investigations of fish behavior in relation to vessel noise (Olsen 
et al. 1983; Ona 1988; Ona and Godo 1990) have shown that fish react 
when the sound from the engines and propeller exceeds a certain level. 
Avoidance reactions have been observed in fish such as cod and herring 
when vessels approached close enough that received sound levels are 110 
dB to 130 dB (Nakken 1992; Olsen 1979; Ona and Godo 1990; Ona and 
Toresen 1988). However, other researchers have found that fish such as 
polar cod, herring, and capeline are often attracted to vessels 
(apparently by the noise) and swim toward the vessel (Rostad et al. 
2006). Typical sound source levels of vessel noise in the audible range 
for fish are 150 dB to 170 dB (Richardson et al. 1995).
    Further, during the seismic survey only a small fraction of the 
available habitat would be ensonified at any given time. Disturbance to 
fish species would be short-term and fish would return to their pre-
disturbance behavior once the seismic activity ceases (McCauley et al. 
2000a, 2000b; Santulli et al. 1999; Pearson et al. 1992). Thus, the 
proposed survey would have little, if any, impact on the abilities of 
marine mammals to feed in the area where seismic work is planned.
    Some mysticetes, including bowhead whales, feed on concentrations 
of zooplankton. Some feeding bowhead whales may occur in the Alaskan 
Beaufort Sea in July and August, and others feed intermittently during 
their westward migration in September and October (Richardson and 
Thomson [eds.] 2002; Lowry et al. 2004). A reaction by zooplankton to a 
seismic impulse would only be relevant to whales if it caused 
concentrations of zooplankton to scatter. Pressure changes of 
sufficient magnitude to cause that type of reaction would probably 
occur only very close to the source. Impacts on zooplankton behavior 
are predicted to be negligible, and that would translate into 
negligible impacts on feeding mysticetes. Thus, the proposed activity 
is not expected to have any habitat-related effects on prey species 
that could cause significant or long-term consequences for individual 
marine mammals or their populations.

Potential Impacts on Availability of Affected Species or Stock for 
Taking for Subsistence Uses

    Subsistence hunting is an essential aspect of Inupiat Native life, 
especially in rural coastal villages. The Inupiat participate in 
subsistence hunting activities in and around the Chukchi Sea. The 
animals taken for subsistence provide a significant portion of the food 
that will last the community through the year. Marine mammals represent 
on the order of 60-80% of the total subsistence harvest. Along with the 
nourishment necessary for survival, the subsistence activities 
strengthen bonds within the culture, provide a means for educating the 
young, provide supplies for artistic expression, and allow for 
important celebratory events.

Potential Impacts to Subsistence Uses

    NMFS has defined ``unmitigable adverse impact'' in 50 CFR 216.103 
as: ``. . . an impact resulting from the specified activity: (1) That 
is likely to reduce the availability of the species to a level 
insufficient for a harvest to meet subsistence needs by: (i) Causing 
the marine mammals to abandon or avoid hunting areas; (ii) Directly 
displacing subsistence users; or (iii) Placing physical barriers 
between the marine mammals and the subsistence hunters; and (2) That 
cannot be sufficiently mitigated by other measures to increase the 
availability of marine mammals to allow subsistence needs to be met.''
(1) Bowhead Whales
    TGS' planned seismic surveys would have no or negligible effects on 
bowhead whale harvest activities. Noise and general activity associated 
with marine surveys and operation of vessels has the potential to 
harass bowhead whales. However, though temporary diversions of the swim 
path of migrating whales have been documented, the whales have 
generally been observed to resume their initial migratory route. The 
proposed open-water seismic surveys and vessel noise could affect 
subsistence hunts by placing the animals further offshore or otherwise 
at a greater distance from villages thereby increasing the difficulty 
of the hunt or

[[Page 35517]]

retrieval of the harvest, or creating a safety risk to the whalers.
    Ten primary coastal Alaskan villages deploy whaling crews during 
whale migrations. Around the TGS' proposed project area in the Chukchi 
Sea, the primary bowhead hunting villages that could be affected are 
Barrow, Wainwright, and Point Hope. Whaling crews in Barrow hunt in 
both the spring and the fall (Funk and Galginaitis 2005). The primary 
bowhead whale hunt in Barrow occurs during spring, while the fall hunt 
is used to meet the quota and seek strikes that can be transferred from 
other communities. In the spring, the whales are hunted along leads 
that occur when the pack ice starts deteriorating. This tends to occur 
between the first week of April through May in Barrow and the first 
week of June in Wainwright, well before the proposed 2D seismic surveys 
would be conducted. The surveys will start after all the ice melts, 
usually near mid-July. The Point Hope bowhead whale hunt occurs from 
March to June. Whaling camps are established on the ice edge south and 
southeast of Point Hope, 10 to 11 km (6 to 7 mi) offshore. Due to ice 
conditions, the Point Hope hunt will likely be completed prior to 
commencement of the surveys. In the fall, whaling activities occur to 
the east of Point Barrow in the Beaufort Sea, while the proposed survey 
activities would be in the west of Point Barrow in the Chukchi Sea.
(2) Beluga Whales
    Belugas typically do not represent a large proportion of the 
subsistence harvests by weight in the communities of Wainwright and 
Barrow. Barrow residents hunt beluga in the spring normally after the 
bowhead hunt) in leads between Point Barrow and Skull Cliffs in the 
Chukchi Sea primarily in April-June, and later in the summer (July-
August) on both sides of the barrier island in Elson Lagoon/Beaufort 
Sea (MMS 2008), but harvest rates indicate the hunts are not frequent. 
Wainwright residents hunt beluga in April-June in the spring lead 
system, but this hunt typically occurs only if there are no bowheads in 
the area. Communal hunts for beluga are conducted along the coastal 
lagoon system later in July-August. Between 2005 and 2009, the annual 
beluga subsistence take was 94 whales (Allen and Angliss 2012) among 
both Wainwright and Barrow.
    Belugas typically represent a much greater proportion of the 
subsistence harvest in Point Lay and Point Hope. Point Lay's primary 
beluga hunt occurs from mid-June through mid-July, but can sometimes 
continue into August if early success is not sufficient. Belugas are 
harvested in coastal waters near these villages, generally within a few 
miles from shore. However, the southern extent of TGS' proposed surveys 
is over 88 m to the north of Point Lay, and much farther away from 
Point Hope. Therefore NMFS considers that the surveys would have no or 
negligible effect on beluga hunts.
(3) Seals
    Seals are an important subsistence resource and ringed seals make 
up the bulk of the seal harvest. Most ringed and bearded seals are 
harvested in the winter or in the spring before TGS' 2013 activities 
would commence, but some harvest continues during open water and could 
possibly be affected by TGS' planned activities. Spotted seals are also 
harvested during the summer. Most seals are harvested in coastal 
waters, with available maps of recent and past subsistence use areas 
indicating seal harvests have occurred only within 30-40 mi (48-64 km) 
off the coastline. TGS does not plan to survey within 88 km (55 mi) of 
the coast, which means that the proposed activities are not likely to 
have an impact on subsistence hunting for seals.
    As stated earlier, the proposed seismic survey would take place 
between July and October. The proposed seismic survey activities would 
be conducted in far offshore waters of the Chukchi Sea and away from 
any subsistent activities. In addition, the timing of the survey 
activities that would be conducted between July and October would 
further avoid any spring hunting activities in Chukchi Sea villages. 
Therefore, due to the time and spatial separation of TGS' proposed 2D 
seismic surveys and the subsistent harvest by the local communities, it 
is anticipated to have no effects on spring harvesting and little or no 
effects on the occasional summer harvest of beluga whale, subsistence 
seal hunts (ringed and spotted seals are primarily harvested in winter 
while bearded seals are hunted during July-September in the Beaufort 
Sea), or the fall bowhead hunt.
    In addition, TGS has developed and proposes to implement a number 
of mitigation measures (described in the next section) which include a 
proposed Marine Mammal Monitoring and Mitigation Plan (4MP), employment 
of subsistence advisors in the villages, and implementation of a 
Communications Plan (with operation of Communication Centers). TGS has 
also prepared a Plan of Cooperation (POC) under 50 CFR 216.104 Article 
12 of the MMPA that addresses potential impacts on subsistent seal 
hunting activities.
    Finally, to ensure that there will be no conflict from TGS' 
proposed open-water seismic surveys to subsistence activities, TGS 
stated that it will maintain communications with subsistence 
communities via the communication centers (Com and Call Centers) and 
signed the Conflict Avoidance Agreement (CAA) with Alaska whaling 
communities.

Proposed Mitigation

    In order to issue an incidental take authorization under Section 
101(a)(5)(D) of the MMPA, NMFS must set forth the permissible methods 
of taking pursuant to such activity, and other means of effecting the 
least practicable adverse impact on such species or stock and its 
habitat, paying particular attention to rookeries, mating grounds, and 
areas of similar significance, and on the availability of such species 
or stock for taking for certain subsistence uses.
    For the proposed TGS open-water marine 2D seismic surveys in the 
Chukchi Sea, TGS worked with NMFS and proposed the following mitigation 
measures to minimize the potential impacts to marine mammals in the 
project vicinity as a result of the marine seismic survey activities. 
The primary purpose of these mitigation measures is to detect marine 
mammals within, or about to enter designated exclusion zones and to 
initiate immediate shutdown or power down of the airgun(s), therefore 
it is very unlikely potential injury or TTS to marine mammals would 
occur, and Level B behavioral of marine mammals would be reduced to the 
lowest level practicable.

(1) Establishing Exclusion and Disturbance Zones

    Under current NMFS guidelines, the ``exclusion zone'' for marine 
mammal exposure to impulse sources is customarily defined as the area 
within which received sound levels are >=180 dB (rms) re 1 [mu]Pa for 
cetaceans and >=190 dB (rms) re 1 [mu]Pa for pinnipeds. These safety 
criteria are based on an assumption that SPL received at levels lower 
than these will not injure these animals or impair their hearing 
abilities, but that at higher levels might have some such effects. 
Disturbance or behavioral effects to marine mammals from underwater 
sound may occur after exposure to sound at distances greater than the 
exclusion zones (Richarcdson et al. 1995). Currently, NMFS uses 160 dB 
(rms) re 1 [mu]Pa as the threshold for Level B behavioral harassment 
from impulses noise.

[[Page 35518]]

    The acoustic source level of the proposed 3,280 in\3\ seismic 
source array was predicted using JASCO's airgun array source model 
(AASM) based on data collected from three sites chosen in the project 
area by JASCO. Water depths at the three sites were 17, 40, and 100 m. 
JASCO applied its Marine Operations Noise Model (MONM) to estimate 
acoustic propagation of the proposed seismic source array and the 
associated distances to the 190, 180 and 160 dB (rms) re 1 [mu]Pa 
isopleths relative to standard NMFS mitigation and monitoring 
requirements for marine mammals. The resulting isopleths modeled for 
the 180 and 190 dB (rms) re 1 [mu]Pa exclusion zone distances for 
cetaceans and pinnipeds, respectively, differed with the three water 
depths. An additional 10 percent distance buffer was added by JASCO to 
these originally modeled distances to provide larger, more protective 
exclusion zone radii. The modeled exclusion zones and zones of 
influence are listed in Table 1.
    These safety distances will be implemented at the commencement of 
2013 airgun operations to establish marine mammal exclusion zones used 
for mitigation. TGS will conduct sound source measurements of the 
airgun array at the beginning of survey operations in 2013 to verify 
the size of the various marine mammal exclusion zones. The acoustic 
data will be analyzed as quickly as reasonably practicable in the field 
and used to verify and adjust the marine mammal exclusion zone 
distances. The mitigation measures to be implemented at the 190 and 180 
dB (rms) sound levels will include power downs and shut downs as 
described below.

(2) Vessel Related Mitigation Measures

    This proposed mitigation measures apply to all vessels that are 
part of the Chukchi Sea seismic survey activities, including the 
supporting vessel.
     Avoid concentrations or groups of whales by all vessels 
under the direction of TGS. Operators of vessels should, at all times, 
conduct their activities at the maximum distance possible from such 
concentrations of whales.
     Vessels in transit shall be operated at speeds necessary 
to ensure no physical contact with whales occurs. If any vessel 
approaches within 1.6 km (1 mi) of observed bowhead whales, except when 
providing emergency assistance to whalers or in other emergency 
situations, the vessel operator will take reasonable precautions to 
avoid potential interaction with the bowhead whales by taking one or 
more of the following actions, as appropriate:
    [cir] Reducing vessel speed to less than 5 knots within 300 yards 
(900 feet or 274 m) of the whale(s);
    [cir] Steering around the whale(s) if possible;
    [cir] Operating the vessel(s) in such a way as to avoid separating 
members of a group of whales from other members of the group;
    [cir] Operating the vessel(s) to avoid causing a whale to make 
multiple changes in direction; and
    [cir] Checking the waters immediately adjacent to the vessel(s) to 
ensure that no whales will be injured when the propellers are engaged.
     When weather conditions require, such as when visibility 
drops, adjust vessel speed accordingly to avoid the likelihood of 
injury to whales.

(3) Mitigation Measures for Airgun Operations

    The primary role for airgun mitigation during the seismic surveys 
is to monitor marine mammals near the airgun array during all daylight 
airgun operations and during any nighttime start-up of the airguns. 
During the seismic surveys PSOs will monitor the pre-established 
exclusion zones for the presence of marine mammals. When marine mammals 
are observed within, or about to enter, designated safety zones, PSOs 
have the authority to call for immediate power down (or shutdown) of 
airgun operations as required by the situation. A summary of the 
procedures associated with each mitigation measure is provided below.

Ramp Up Procedure

    A ramp up of an airgun array provides a gradual increase in sound 
levels, and involves a step-wise increase in the number and total 
volume of airguns firing until the full volume is achieved. The purpose 
of a ramp up (or ``soft start'') is to ``warn'' cetaceans and pinnipeds 
in the vicinity of the airguns and to provide time for them to leave 
the area and thus avoid any potential injury or impairment of their 
hearing abilities.
    During the proposed open-water survey program, the seismic operator 
will ramp up the airgun arrays slowly. Full ramp ups (i.e., from a cold 
start after a shut down, when no airguns have been firing) will begin 
by firing a single airgun in the array (i.e., the mitigation airgun). A 
full ramp up, after a shut down, will not begin until there has been a 
minimum of 30 min of observation of the safety zone by PSOs to assure 
that no marine mammals are present. The entire exclusion zone must be 
visible during the 30-minute lead-in to a full ramp up. If the entire 
exclusion zone is not visible, then ramp up from a cold start cannot 
begin. If a marine mammal(s) is sighted within the safety zone during 
the 30-minute watch prior to ramp up, ramp up will be delayed until the 
marine mammal(s) is sighted outside of the exclusion zone or the 
animal(s) is not sighted for at least 15-30 minutes: 15 minutes for 
small odontocetes (harbor porpoise) and pinnipeds, or 30 minutes for 
baleen whales and large odontocetes (including beluga and killer whales 
and narwhal).

Use of a Small-Volume Airgun During Turns and Transits

    Throughout the seismic survey, particularly during turning 
movements, and short transits, TGS will employ the use of a small-
volume airgun (i.e., 60 in\3\ ``mitigation airgun'') to deter marine 
mammals from being within the immediate area of the seismic operations. 
The mitigation airgun would be operated at approximately one shot per 
minute and would not be operated for longer than three hours in 
duration (turns may last two to three hours for the proposed project) 
during daylight hours. In cases when the next start-up after the turn 
is expected to be during lowlight or low visibility, continuous 
operation of mitigation airgun is permitted.
    During turns or brief transits (e.g., less than three hours) 
between seismic tracklines, one mitigation airgun will continue 
operating. The ramp-up procedure will still be followed when increasing 
the source levels from one airgun to the full airgun array. However, 
keeping one airgun firing will avoid the prohibition of a ``cold 
start'' during darkness or other periods of poor visibility. Through 
use of this approach, seismic surveys using the full array may resume 
without the 30 minute observation period of the full exclusion zone 
required for a ``cold start.'' PSOs will be on duty whenever the 
airguns are firing during daylight, during the 30 minute periods prior 
to ramp-ups.

Power-Down and Shut Down Procedures

    A power down is the immediate reduction in the number of operating 
energy sources from all firing to some smaller number (e.g., single 
mitigation airgun). A shut down is the immediate cessation of firing of 
all energy sources. The array will be immediately powered down whenever 
a marine mammal is sighted approaching close to or within the 
applicable safety zone of the full array, but is outside the applicable 
safety zone of the single mitigation source. If a marine mammal is 
sighted within or about to enter the applicable safety zone of the 
single mitigation

[[Page 35519]]

airgun, the entire array will be shut down (i.e., no sources firing).

Poor Visibility Conditions

    TGS plans to conduct 24-hour operations. PSOs will not be on duty 
during ongoing seismic operations during darkness, given the very 
limited effectiveness of visual observation at night (there will be no 
periods of darkness in the survey area until mid-August). The proposed 
provisions associated with operations at night or in periods of poor 
visibility include the following:
     If during foggy conditions, heavy snow or rain, or 
darkness (which may be encountered starting in late August), the full 
180 dB exclusion zone is not visible, the airguns cannot commence a 
ramp-up procedure from a full shut-down.
     If one or more airguns have been operational before 
nightfall or before the onset of poor visibility conditions, they can 
remain operational throughout the night or poor visibility conditions. 
In this case ramp-up procedures can be initiated, even though the 
exclusion zone may not be visible, on the assumption that marine 
mammals will be alerted by the sounds from the single airgun and have 
moved away.

(4) Mitigation Measures for Subsistence Activities

    Regulations at 50 CFR 216.104(a)(12) require IHA applicants for 
activities that take place in Arctic waters to provide a Plan of 
Cooperation (POC) or information that identifies what measures have 
been taken and/or will be taken to minimize adverse effects on the 
availability of marine mammals for subsistence purposes.
    TGS has prepared a POC, which relies upon the Chukchi Sea 
Communication Plans to identify the measures that TGS has developed in 
consultation with North Slope subsistence communities and will 
implement during its planned 2013 activities to minimize any adverse 
effects on the availability of marine mammals for subsistence uses. The 
POC describes important subsistence activities near the proposed survey 
program and summarizes actions TGS has taken to inform subsistence 
communities of the proposed survey activities; and measures it will 
take to minimize adverse effects on marine mammals where proposed 
activities may affect the availability of a species or stock of marine 
mammals for arctic subsistence uses or near a traditional subsistence 
hunting area.
    TGS began stakeholder engagement by introducing the project to the 
North Slope Borough (NSB) Planning Commission on October 25, 2012, and 
it also met with the NSB Planning Director and other Barrow leadership. 
In December 2012, TGS met with Chukchi Sea community leaders at the 
tribal, city, and corporate level in Barrow, Wainwright, Point Hope, 
Point Lay, and Kotzebue. TGS also introduced the project to the Alaska 
Eskimo Whaling Commission (AEWC) at their 4th Quarter Meeting on 
December 13-14, 2012, in Anchorage.
    Community POC meetings were held in Barrow, Kotzebue, Point Hope, 
Point Lay, and Wainwright in January and February 2013. Finally, in 
February 2013, TGS participated the AEWC mini-convention and on 
Conflict Avoidance Agreement (CAA) discussion. A final POC that 
documents all consultations with community leaders and subsistence 
users was submitted to NMFS in May, 2013.
    In addition, TGS signed a CAA with the Alaska whaling communities 
to further ensure that its proposed open-water seismic survey 
activities in the Chukchi Sea will not have unmitigable impacts to 
subsistence activities. NMFS has included appropriate measures 
identified in the CAA in the IHA.

Mitigation Conclusions

    NMFS has carefully evaluated the applicant's proposed mitigation 
measures and considered a range of other measures in the context of 
ensuring that NMFS prescribes the means of effecting the least 
practicable impact on the affected marine mammal species and stocks and 
their habitat. Our evaluation of potential measures included 
consideration of the following factors in relation to one another:
     The manner in which, and the degree to which, the 
successful implementation of the measure is expected to minimize 
adverse impacts to marine mammals; and
     The practicability of the measure for applicant 
implementation.
    Based on our evaluation of the applicant's proposed measures, as 
well as other measures considered by NMFS, NMFS has preliminarily 
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.

Proposed Monitoring and Reporting

    In order to issue an ITA for an activity, Section 101(a)(5)(D) of 
the MMPA states that NMFS must set forth ``requirements pertaining to 
the monitoring and reporting of such taking''. The MMPA implementing 
regulations at 50 CFR 216.104(a)(13) indicate that requests for ITAs 
must include the suggested means of accomplishing the necessary 
monitoring and reporting that will result in increased knowledge of the 
species and of the level of taking or impacts on populations of marine 
mammals that are expected to be present in the proposed action area.
I. Proposed Monitoring Measures
    The monitoring plan proposed by TGS can be found in its Marine 
Mammal Monitoring and Mitigation Plan (4MP). The plan may be modified 
or supplemented based on comments or new information received from the 
public during the public comment period. A summary of the primary 
components of the plan follows.
    Monitoring will provide information on the numbers of marine 
mammals potentially affected by the exploration operations and 
facilitate real time mitigation to prevent injury of marine mammals by 
industrial sounds or activities. These goals will be accomplished in 
the Chukchi Sea during 2013 by conducting vessel-based monitoring from 
both source vessel and supporting vessel and an acoustic monitoring 
program to using towed hydrophone array to document marine mammal 
presence and distribution in the vicinity of the survey area beyond 
visual observation distances.
    Visual monitoring by Protected Species Observers (PSOs) during 
active marine survey operations, and periods when these surveys are not 
occurring, will provide information on the numbers of marine mammals 
potentially affected by these activities and facilitate real time 
mitigation to prevent impacts to marine mammals by industrial sounds or 
operations. Vessel-based PSOs onboard the survey vessel will record the 
numbers and species of marine mammals observed in the area and any 
observable reaction of marine mammals to the survey activities in the 
Chukchi Sea.
    Real-time PAM would be conducted from the supporting vessel to 
complement the visual monitoring conducted by PSOs during the seismic 
surveys in the Chukchi Sea. Studies have indicated that towed PAM is a 
practical and successful application for augmenting visual surveys of 
low-frequency mysicetes, including blue and fin whales (Clark and 
Fristrup 1997). Passive acoustics methods, including towed hydrophone 
arrays, are most effective in remote areas, harsh environments (e.g. 
the arctic) and when visibility and/or sea conditions are poor,

[[Page 35520]]

or at nighttime or during low-light conditions when animals cannot be 
sighted easily. Surveys have collected more acoustic detections than 
visual observations while using towed PAM in the Arctic during an open-
water seismic survey program conducted by Statoil in 2010 (McPherson et 
al. 2012). TGS states that the designed PAM system would provide the 
possibility of advanced real-time notification of vocalizing marine 
mammals that are not observed visually (or are observed after acoustic 
detection) and allow for mitigation actions (i.e., power-down, shut-
down) to take place, if necessary.

Visual-Based Protected Species Observers (PSOs)

    The visual-based marine mammal monitoring will be implemented by a 
team of experienced PSOs, including both biologists and Inupiat 
personnel. PSOs will be stationed aboard the survey and supporting 
vessels through the duration of the project. The vessel-based marine 
mammal monitoring will provide the basis for real-time mitigation 
measures as discussed in the Proposed Mitigation section. In addition, 
monitoring results of the vessel-based monitoring program will include 
the estimation of the number of ``takes'' as stipulated in the IHA.
(1) Protected Species Observers
    Vessel-based monitoring for marine mammals will be done by trained 
PSOs throughout the period of survey activities. The observers will 
monitor the occurrence of marine mammals near the survey vessel during 
all daylight periods during operation, and during most daylight periods 
when operations are not occurring. PSO duties will include watching for 
and identifying marine mammals; recording their numbers, distances, and 
reactions to the survey operations; and documenting ``take by 
harassment''.
    A sufficient number of PSOs will be required onboard the survey 
vessel to meet the following criteria:
     100% monitoring coverage during all periods of survey 
operations in daylight;
     maximum of 4 consecutive hours on watch per PSO; and
     maximum of 12 hours of watch time per day per PSO.
    PSO teams will consist of Inupiat observers and experienced field 
biologists. Each vessel will have an experienced field crew leader to 
supervise the PSO team. The total number of PSOs may decrease later in 
the season as the duration of daylight decreases.
(2) Observer Qualifications and Training
    Crew leaders and most PSOs will be individuals with experience as 
observers during recent seismic, site clearance and shallow hazards, 
and other monitoring projects in Alaska or other offshore areas in 
recent years.
    Biologist-observers will have previous marine mammal observation 
experience, and field crew leaders will be highly experienced with 
previous vessel-based marine mammal monitoring and mitigation projects. 
Resumes for those individuals will be provided to NMFS for review and 
acceptance of their qualifications. Inupiat observers will be 
experienced in the region and familiar with the marine mammals of the 
area. All observers will complete a NMFS-approved observer training 
course designed to familiarize individuals with monitoring and data 
collection procedures.
    PSOs will complete a two or three-day training and refresher 
session on marine mammal monitoring, to be conducted shortly before the 
anticipated start of the 2013 open-water season. Any exceptions will 
have or receive equivalent experience or training. The training 
session(s) will be conducted by qualified marine mammalogists with 
extensive crew-leader experience during previous vessel-based seismic 
monitoring programs.

Marine Mammal Observer Protocol

    The PSOs will watch for marine mammals from the best available 
vantage point on the survey vessels, typically the bridge. The PSOs 
will scan systematically with the unaided eye and 7 x 50 reticle 
binoculars, supplemented with 20 x 60 image-stabilized Zeiss Binoculars 
or Fujinon 25 x 150 ``Big-eye'' binoculars, and night-vision equipment 
when needed. Personnel on the bridge will assist the marine mammal 
observer(s) in watching for marine mammals.
    The observer(s) aboard the survey and support vessels will give 
particular attention to the areas within the marine mammal exclusion 
zones around the source vessel. These zones are the maximum distances 
within which received levels may exceed 180 dB (rms) re 1 [micro]Pa 
(rms) for cetaceans, or 190 dB (rms) re 1 [micro]Pa for pinnipeds.
    Distances to nearby marine mammals will be estimated with 
binoculars (Fujinon 7 x 50 binoculars) containing a reticle to measure 
the vertical angle of the line of sight to the animal relative to the 
horizon. Observers may use a laser rangefinder to test and improve 
their abilities for visually estimating distances to objects in the 
water.
    When a marine mammal is seen approaching or within the exclusion 
zone applicable to that species, the marine survey crew will be 
notified immediately so that mitigation measures called for in the 
applicable authorization(s) can be implemented.
    Night-vision equipment (Generation 3 binocular image intensifiers 
or equivalent units) will be available for use when/if needed. Past 
experience with night-vision devices (NVDs) in the Chukchi Sea and 
elsewhere has indicated that NVDs are not nearly as effective as visual 
observation during daylight hours (e.g., Harris et al. 1997, 1998; 
Moulton and Lawson 2002).

Field Data-Recording

    The PSOs aboard the vessels will maintain a digital log of seismic 
surveys, noting the date and time of all changes in seismic activity 
(ramp-up, power-down, changes in the active seismic source, shutdowns, 
etc.) and any corresponding changes in monitoring radii in a project-
customized Mysticetus\TM\ observation software spreadsheet. In 
addition, PSOs will utilize this standardized format to record all 
marine mammal observations and mitigation actions (seismic source 
power-downs, shut-downs, and ramp-ups). Information collected during 
marine mammal observations will include the following:
     Vessel speed, position, and activity
     Date, time, and location of each marine mammal sighting
     Number of marine mammals observed, and group size, sex, 
and age categories
     Observer's name and contact information
     Weather, visibility, and ice conditions at the time of 
observation
     Estimated distance of marine mammals at closest approach
     Activity at the time of observation, including possible 
attractants present
     Animal behavior
     Description of the encounter
     Duration of encounter
     Mitigation action taken
    Data will preferentially be recorded directly into handheld 
computers or as a back-up, transferred from hard-copy data sheets into 
an electronic database. A system for quality control and verification 
of data will be facilitated by the pre-season training, supervision by 
the lead PSOs, in-season data checks, and will be built into the 
Mysticetus\TM\ software (i.e., Mysticetus\TM\ will recognize and notify 
the operator if entered data are non-sensical). Computerized data 
validity checks will also be conducted, and the data will be managed in 
such a way that it is easily

[[Page 35521]]

summarized during and after the field program and transferred into 
statistical, graphical, or other programs for further processing. 
Mysticetus\TM\ will be used to quickly and accurately summarize and 
display these data.

Passive Acoustic Monitoring

(1) Sound Source Measurements
    Prior to or at the beginning of the seismic survey, sound levels 
will be measured as a function of distance and direction from the 
proposed seismic source array (full array and reduced to a single 
mitigation airgun). Results of the acoustic characterization and SSV 
will be used to empirically refine the modeled distance estimates of 
the pre-season 190 dB, 180 dB, and 160 dB isopleths. The refined SSV 
exclusion zones will be used for the remainder of the seismic survey. 
Distance estimates for the 120 dB isopleth will also be modeled. The 
results of the SSV will be submitted to NMFS within five days after 
completing the measurements, followed by a report in 14 days. A more 
detailed report will be provided to NMFS as part of the 90-day report 
following completion of the acoustic program.
(2) Real-Time Passive Acoustic Monitoring
    TGS will conduct real-time passive acoustic monitoring using a 
towed hydrophone array from the support vessel. The towed hydrophone 
array system consists of two parts: The ``wet end'' and the ``dry 
end''. The wet end consists of the hydrophone array and tow cable that 
is towed behind the vessel. The dry end includes the analog-to-digital, 
computer processing, signal conditioning and filtering system used to 
process, record and analyze the acoustic data. Specific noise filters 
will be used to maximize the systems ability to detect low frequency 
bowhead whales. The towed hydrophone array will be deployed using a 
winch from the scout vessel. Details and specifications on the 
equipment will be determined at a later date once TGS has selected an 
acoustics contractor, as each contractor has different equipment 
specifications.
    Localization of vocalizing animals will be accomplished using 
target motion analysis. With this method, it is possible with a single 
towed hydrophone array to obtain a localization to vocalizing animals 
given certain assumptions. Due to the linear alignment of hydrophones, 
there is a left/right ambiguity that cannot be resolved without turning 
the tow vessel. The left/right ambiguity, however, is not a critical 
concern for mitigation during the TGS 2D seismic survey because the 
exclusion zones are circular; therefore, the distance to the calling 
animal is the same on the right and left side of the vessel. 
Furthermore, unambiguous localization can be achieved in circumstances 
where the vessel towing the array can turn and the calling animals call 
multiple times or continuously.
    To ensure the effectiveness of real-time PAM with a towed 
hydrophone array, the following requirements for PAM design and 
procedures will be required:

Lowering Interferences From Flow Noise

     Limit towing speeds to 4-6 knots. Reduce speed 
appropriately if bowhead whales are detected so that bearing can be 
obtained. If greater speeds are necessary, slow down every 20-30 
minutes to listen for animal calls for at least 5-10 minutes.
     Maintain straight track[hyphen]lines unless right/left 
ambiguity must be resolved (usually by turning 20-30 degrees at a time, 
then maintaining a straight course until good bearings can be 
obtained).
     Maintain a separation distance of at least several hundred 
meters (preferably more) from the seismic survey vessel.
     Design pre[hyphen]amplifier filters that are `tuned' to 
reduce low[hyphen]frequency flow and vessel noise.
     If necessary, use a variable high[hyphen]pass filter 
before digitizing the signals.

Monitoring Marine Mammal Occurrence Within 160 dB Isopleths

     Design a hydrophone array that is sensitive to frequencies 
of interest (e.g. marine mammal sounds) but attenuates (via filters) 
noise.
     Use a processing system that can further signal conditions 
(i.e. filter and match signal gains) to allow software to effectively 
estimate bearings and/or localize.
     Use software designed exclusively for monitoring, 
localizing and plotting marine mammal calls.
     Design the sampling software to optimize overlap between 
monitoring the 180 and 160 dB isopleths.
     Allow the survey vessel to deviate from designated 
track[hyphen]lines by 25-30 degrees (for brief periods) so that left/
right ambiguity can be resolved.

Increase Localization Capability

     Start with a simple hydrophone array, and if needed, add 
additional capabilities (or hydrophones) to supplement this system. For 
example, a 2[hyphen]hydrophone array that can do TMA but with an 
additional array (or inline section) that can be added in front of the 
primary array would allow crossed[hyphen]pair localization methods to 
be used.
     Use a processing and geographic display system that can 
accommodate at least the TMA localization method, but also, additional 
methods if needed.
     Provide at least 300 m of cable (for TMA methods), and up 
to 500 m if crossed[hyphen]pair or hyperbolic localization methods will 
be used.

Monitoring Plan Peer Review

    The MMPA requires that monitoring plans be independently peer 
reviewed ``where the proposed activity may affect the availability of a 
species or stock for taking for subsistence uses'' (16 U.S.C. 
1371(a)(5)(D)(ii)(III)). Regarding this requirement, NMFS' implementing 
regulations state, ``Upon receipt of a complete monitoring plan, and at 
its discretion, [NMFS] will either submit the plan to members of a peer 
review panel for review or within 60 days of receipt of the proposed 
monitoring plan, schedule a workshop to review the plan'' (50 CFR 
216.108(d)).
    NMFS convened an independent peer review panel to review TGS' 
mitigation and monitoring plan in its IHA application for taking marine 
mammals incidental to the proposed open-water marine surveys and 
equipment recovery and maintenance in the Chukchi Sea during 2013. The 
panel met on January 8 and 9, 2013, and provided their final report to 
NMFS in March 2013. The full panel report can be viewed at: https://www.nmfs.noaa.gov/pr/permits/incidental.htm#applications.
    NMFS provided the panel with TGS' monitoring and mitigation plan 
and asked the panel to address the following questions and issues for 
TGS' plan:
     Will the applicant's stated objectives effectively further 
the understanding of the impacts of their activities on marine mammals 
and otherwise accomplish the goals stated below? If not, how should the 
objectives be modified to better accomplish the goals above?
     Can the applicant achieve the stated objectives based on 
the methods described in the plan?
     Are there technical modifications to the proposed 
monitoring techniques and methodologies proposed by the applicant that 
should be considered to better accomplish their stated objectives?
     Are there techniques not proposed by the applicant (i.e., 
additional monitoring techniques or methodologies) that should be 
considered for inclusion in the applicant's monitoring program to 
better accomplish their stated objectives?

[[Page 35522]]

     What is the best way for an applicant to present their 
data and results (formatting, metrics, graphics, etc.) in the required 
reports that are to be submitted to NMFS (i.e., 90-day report and 
comprehensive report)?
    The peer review panel report contains recommendations that the 
panel members felt were applicable to the TGS' monitoring plans. The 
panel agrees that the objective of vessel-based monitoring to implement 
mitigation measures to prevent or limit Level A takes is appropriate. 
In addition, at the time the panel reviewed the TGS' proposed marine 
mammal monitoring and mitigation plan, TGS only proposed vessel-based 
visual monitoring (but subsequently added PAM as described above). The 
panel was particularly concerned that there are considerable 
limitations to the ability of PSOs to monitor the full extent of the 
zones of influence, as these zones extend to as far as 15 km beyond the 
source. In addition, the panel pointed out that TGS did not specify how 
it planned to operate the scout vessel for marine mammal monitoring.
    Specific recommendations provided by the peer review panel to 
enhance marine mammal monitoring, especially far distance monitoring 
beyond exclusion zones, include: (1) Implementing passive acoustic 
monitoring, with the bottom mounted passive acoustic recorders probably 
being the most appropriate method; (2) deploying a real-time, passive 
acoustic monitoring device that is linked by satellite (i.e., Iridium) 
phone; (3) collaborating with NMFS to use aerial survey data for 
assessing marine mammal distribution, relative abundance, behavior, and 
possible impacts relative to seismic surveys; (4) looking into 
possibility of using unmanned aerial systems to survey for marine 
mammals in offshore areas; and (5) utilizing new technologies, such as 
underwater vehicles, gliders, satellite monitoring, etc., to conduct 
far-field monitoring.
    NMFS discussed extensively with TGS to improve the far-field marine 
mammal monitoring. As a result, upon further investigation and 
conversations with both JASCO and Bio-Waves by TGS, as well as further 
research into past Arctic marine mammal monitoring results conducted 
with towed-PAM, NMFS and TGS agree that utilizing a well-designed 
towed-PAM system would meet the need to provide enhanced marine mammal 
monitoring beyond exclusion zones, as well as using acoustic data for 
limited relative abundance and distribution analysis, and possibly 
limited insights on impacts to marine mammals.
    NMFS also studied other PAM methodologies suggested by the peer-
review panel. First, concerning deploying fixed bottom mounted 
recorders, TGS states that it has been in contact with other operators 
but was not able to find a collaborator to participate in long-term 
acoustic monitoring due to the short-term nature of the proposed 
survey. Regarding the real-time acoustic monitoring with fixed buoy, 
TGS stated that it conducted an evaluation of this option and discussed 
the possibility with the Cornell University's Bioacoustical Research 
Program concerning its real-time marine acoustic recording unit (MARU), 
but decided that the technology is still in the research and 
development stage. TGS also states that it did not consider the 
technology because the cost is more expensive than other PAM methods. 
TGS also discussed (with NMFS scientists) the possibility of using 
NMFS' aerial survey data for assessing marine mammal distribution, 
relative abundance, and possible impacts relative to seismic surveys. 
However, most of TGS' survey areas are outside NMFS aerial survey area, 
which makes it im possible to use these datasets for impact analyses. 
TGS also did a cost-benefit analysis of manned aerial surveys, and 
eliminated this as an option due to increased health and safety 
exposure risk, especially north of 72[deg] N. TGS also investigated the 
possibility of using unmanned aerial vehicle (UAV) to survey for marine 
mammals in offshore areas, however, it has also turned out not to be 
feasible due to the fact that the approach is currently awaiting an FAA 
permit to operate in the Arctic, and this permit could not be 
guaranteed to be obtained in time for the TGS monitoring effort. TGS 
states that it did consider new technologies, but did not feel that 
they could justify the expense of testing techniques with unknown 
capabilities in the Arctic environment.
    In addition, the panel also recommends that TGS collaborate with 
other organizations operating in the Chukchi Sea and share visual and 
acoustic data to improve understanding of impacts from single and 
multiple operations and efficacy of mitigation measures. Accordingly, 
TGS plans to share these data via the OBIS-SEAMAP Web site entertaining 
all appropriate data-sharing agreements, including data obtained using 
towed PAM.
II. Reporting Measures
Sound Source Verification Reports
    A report on the preliminary results of the sound source 
verification measurements, including the measured 190, 180, and 160 dB 
(rms) radii of the airgun sources, would be submitted within 14 days 
after collection of those measurements at the start of the field 
season. This report will specify the distances of the exclusion zones 
that were adopted for the survey.
Field Reports
    Throughout the survey program, PSOs will prepare a report each day 
or at such other intervals, summarizing the recent results of the 
monitoring program. The reports will summarize the species and numbers 
of marine mammals sighted. These reports will be provided to NMFS and 
to the survey operators.
Technical Reports
    The results of TGS' 2013 vessel-based monitoring, including 
estimates of ``take'' by harassment, would be presented in the ``90-
day'' and Final Technical reports, if the IHA is issued for the 
proposed open-water 2D seismic surveys. The Technical Reports should be 
submitted to NMFS within 90 days after the end of the seismic survey. 
The Technical Reports will include:
    (a) summaries of monitoring effort (e.g., total hours, total 
distances, and marine mammal distribution through the study period, 
accounting for sea state and other factors affecting visibility and 
detectability of marine mammals);
    (b) analyses of the effects of various factors influencing 
detectability of marine mammals (e.g., sea state, number of observers, 
and fog/glare);
    (c) species composition, occurrence, and distribution of marine 
mammal sightings, including date, water depth, numbers, age/size/gender 
categories (if determinable), group sizes, and ice cover;
    (d) To better assess impacts to marine mammals, data analysis 
should be separated into periods when a seismic airgun array (or a 
single mitigation airgun) is operating and when it is not. Final and 
comprehensive reports to NMFS should summarize and plot:
     Data for periods when a seismic array is active and when 
it is not; and
     The respective predicted received sound conditions over 
fairly large areas (tens of km) around operations;
    (e) sighting rates of marine mammals during periods with and 
without airgun activities (and other variables that could affect 
detectability), such as:
     initial sighting distances versus airgun activity state;

[[Page 35523]]

     closest point of approach versus airgun activity state;
     observed behaviors and types of movements versus airgun 
activity state;
     numbers of sightings/individuals seen versus airgun 
activity state;
     distribution around the survey vessel versus airgun 
activity state; and
     estimates of take by harassment;
    (f) Reported results from all hypothesis tests should include 
estimates of the associated statistical power when practicable;
    (g) Estimate and report uncertainty in all take estimates. 
Uncertainty could be expressed by the presentation of confidence 
limits, a minimum-maximum, posterior probability distribution, etc.; 
the exact approach would be selected based on the sampling method and 
data available;
    (h) The report should clearly compare authorized takes to the level 
of actual estimated takes; and
    (i) Methodology used to estimate marine mammal takes and relative 
abundance on towed PAM.

Notification of Injured or Dead Marine Mammals

    In addition, NMFS would require TGS to notify NMFS' Office of 
Protected Resources and NMFS' Stranding Network within 48 hours of 
sighting an injured or dead marine mammal in the vicinity of marine 
survey operations. TGS shall provide NMFS with the species or 
description of the animal(s), the condition of the animal(s) (including 
carcass condition if the animal is dead), location, time of first 
discovery, observed behaviors (if alive), and photo or video (if 
available).
    In the event that an injured or dead marine mammal is found by TGS 
that is not in the vicinity of the proposed open-water marine survey 
program, TGS would report the same information as listed above as soon 
as operationally feasible to NMFS.

Estimated Take by Incidental Harassment

    Except with respect to certain activities not pertinent here, the 
MMPA defines ``harassment'' as: any act of pursuit, torment, or 
annoyance which (i) has the potential to injure a marine mammal or 
marine mammal stock in the wild [Level A harassment]; or (ii) has the 
potential to disturb a marine mammal or marine mammal stock in the wild 
by causing disruption of behavioral patterns, including, but not 
limited to, migration, breathing, nursing, breeding, feeding, or 
sheltering [Level B harassment]. Only take by Level B behavioral 
harassment is anticipated as a result of the proposed open water marine 
survey program. Anticipated impacts to marine mammals are associated 
with noise propagation from the survey airgun(s) used in the seismic 
surveys.
    The full suite of potential impacts to marine mammals was described 
in detail in the ``Potential Effects of the Specified Activity on 
Marine Mammals'' section found earlier in this document. The potential 
effects of sound from the proposed open water marine survey programs 
might include one or more of the following: masking of natural sounds; 
behavioral disturbance; non-auditory physical effects; and, at least in 
theory, temporary or permanent hearing impairment (Richardson et al. 
1995). As discussed earlier in this document, the most common impact 
will likely be from behavioral disturbance, including avoidance of the 
ensonified area or changes in speed, direction, and/or diving profile 
of the animal. For reasons discussed previously in this document, 
hearing impairment (TTS and PTS) is highly unlikely to occur based on 
the proposed mitigation and monitoring measures that would preclude 
marine mammals from being exposed to noise levels high enough to cause 
hearing impairment.
    For impulse sounds, such as those produced by airgun(s) used in the 
2D seismic surveys, NMFS uses the 160 dB (rms) re 1 [mu]Pa isopleth to 
indicate the onset of Level B harassment. TGS provided calculations for 
the 160-dB isopleths produced by the proposed seismic surveys and then 
used those isopleths to estimate takes by harassment. NMFS used the 
calculations to make the necessary MMPA preliminary findings. TGS 
provided a full description of the methodology used to estimate takes 
by harassment in its IHA application, which is also provided in the 
following sections.

Basis for Estimating ``Take by Harassment''

    The estimated takes by harassment is calculated in this section by 
multiplying the expected densities of marine mammals that may occur 
near the planned activities by the area of water likely to be exposed 
to impulse sound levels of >=160 dB (rms) re 1 [mu]Pa.
    Marine mammal occurrence near the operation is likely to vary by 
season and habitat, mostly related to the presence or absence of sea 
ice. Although current NMFS' noise exposure standards state that Level B 
harassment occurs at exposure levels >=160 dB (rms) re 1 [mu]Pa by 
impulse sources, there is no evidence that avoidance at these received 
sound levels would have significant biological effects on individual 
animals. Any changes in behavior caused by sounds at or near the 
specified received levels would likely fall within the normal variation 
in such activities that would occur in the absence of the planned 
operations. However, these received levels are currently used to set 
the threshold for Level B behavioral harassment.

Marine Mammal Density Estimates

    The first step in estimating the number of marine mammals that 
might be ``taken by harassment'' was to conduct a review of available 
data on density estimates for the marine mammal species occurring in 
the project vicinity and adjacent areas of the Chukchi Sea. While 
several densities are available for U.S. waters in the Chukchi Sea, no 
reliable estimates are known for U.S. waters north of 72[deg] N. 
Furthermore, no systematic surveys are known for the western half of 
the proposed project area in international waters.
    Therefore, densities used to estimate exposures were based on two 
recent IHA applications and three 90-day reports to NMFS summarizing 
results of field monitoring surveys. These project areas overlapped the 
proposed TGS project area to at least some extent as well as TGS' 
proposed July-October seismic operations period. A map showing the 
boundaries of these survey areas relative to TGS' proposed seismic line 
locations is provided in Figure 2 of TGS' IHA application. The surveys 
consisted of the (1) two Statoil 90-day reports from the northern 
Chukchi Sea (Blees et al. 2010; Hartin et al. 2011), (2) UAGI's IHA 
(LGL 2011) and 90-day report (Cameron et al. 2012), and (3) Shell 2012 
IHA (Shell 2011). These data are considered the ``best available'' 
density estimates and occurrence data currently available for the 
project area.
    All recent density estimates for four different project areas 
overlapping the TGS project area based on the observed or derived 
densities reported in other studies (Blees et al. 2010; Hartin et al. 
2011; LGL 2011; Shell 2011; Cameron et al. 2012) and are shown in Table 
3 of TGS' IHA application. Note that only the Cameron et al. (2012) 
survey occurred north of 72[deg] N in U.S. waters and international 
waters partially overlapping the TGS project area. Sightings providing 
data on observed densities were available for the following six 
species: the bowhead, gray and beluga whale, and the bearded, ringed 
and spotted seal. The remaining other six species occur so rarely in 
the project area vicinity that reliable densities are not available for 
them and/or no sightings were made during the

[[Page 35524]]

reported surveys: the humpback, minke, fin, and killer whales, the 
harbor porpoise, and the ribbon seal (Blees et al. 2010; Hartin et al. 
2011; Cameron et al. 2012). Thus, certain fractional numbers were 
assigned to them based on those reported for other IHAs overlapping the 
proposed TGS project area, to address the rare chance of an encounter 
(Blees et al. 2010; Hartin et al. 2011; LGL 2011; Shell 2011; Cameron 
et al. 2012).

Adjustment Factors Applied To Provide Lower and Upper Estimates of 
Density

    A number of habitat parameters have been shown to influence the 
distribution of marine mammal species occurring in the TGS project 
area. These parameters were applied to adjust the density of species 
accordingly, as done by other applicants in previous IHA applications 
(e.g., Blees et al. 2010; Hartin et al. 2011; LGL 2011; Shell 2011, 
Cameron et al. 2012). These included (1) open water (i.e., ice-free) 
vs. ice-edge margin (higher densities of pinnipeds and beluga whales 
occur near and/or within the ice margin), (2) summer (July-August) vs. 
fall (September-October), (3) water depth (>200 vs. <200 m deep), and 
(4) likelihood of occurrence above or below 72[deg] N. Open-water 
densities were used if available because TGS operations must completely 
avoid ice to be able to safely and effectively conduct operations.
    Densities (Table 3 in TGS' IHA application) used to estimate and 
calculate the number of exposures to TGS' seismic impulse sound levels 
>=160 dB (rms) re 1[mu] Pa were obtained by (1) averaging the densities 
from the four previous studies by summer (July-August), fall 
(September-October), and summer-fall, and then (2) multiplying the 
resulting averaged densities by adjustment factors for water depth 
(shallower or deeper than 200 m) and expected occurrence in waters 
north or south of 72[deg] N. Notably, TGS plans to operate above 
72[deg] N for about half (32 days) of the total 45- 60-day period in US 
Federal waters (35 days of which would involve seismic operations), and 
for all operations in international waters, up to 33 days. These 
northern waters above 72[deg] N would be accessed sometime between 
about mid-September and 15 October (when waters are ice-free).
    Because few data were available for most of the survey area, 
particularly north of 72[deg] N and west of Barrow, it is not known how 
closely the applied average densities reflect the actual densities that 
will be encountered during the proposed TGS seismic survey. Thus, lower 
and upper adjustment factors (Table 4 in TGS' IHA application) were 
multiplied by the averaged densities to provide a range of density 
estimates. The latter adjustment was incorporated into a formula to 
estimate exposures to seismic sounds. The ``lower adjustment factor'' 
does not apply adjustment factors to densities north of 72[deg] N for 
the bowhead and beluga whale and the ringed and bearded seal. In 
contrast, the ``upper adjustment factor'' applies factors to account 
for the expected lower density of marine mammal species north of 
72[deg] N. Adjustment factors differed by species and were based on (1) 
the reported distribution and occurrence of each species in these 
waters, and (2) factors applied by ION (LGL 2012) for their 2012 IHA 
application for the fall period of Oct-Dec 2012 that overlapped the 
fall period (mid-to-late September-October) and north-easternmost 
region that TGS expects to operate in international waters during fall.
    TGS applied these density data and factors previously applied in an 
IHA issued to ION to account for expected lower densities above 72[deg] 
N where waters are predominantly >1,000 m deep. The upper-adjusted 
(i.e., lower) density estimate was calculated by multiplying reported 
fall densities for more southern Chukchi waters as follows: (1) by a 
factor of 0.0 for fin, humpback, minke and killer whales, and harbor 
porpoise and ribbon and spotted seals as they are not expected in 
waters above 72[deg] N and thus were assumed not to occur there; (2) by 
an adjustment factor of 0.01 for gray whales (since the northernmost 
boundary of their distribution is near 72[deg] N and they are thus 
considered highly unlikely to occur above 72[deg] N; (3) by a factor of 
0.1 for bowhead whales as the area is outside the main migration 
corridor, and (4) by a factor of 0.1 for beluga whales and bearded and 
ringed seals as they are closely associated with ice, and thus 
considered less likely to occur in ice-free waters needed to conduct 
the TGS seismic operations.
    A similar 0.1 adjustment factor was applied in the ION IHA (LGL 
2012) for species where the seismic survey area was on the edge of that 
species' range at the given time of year. ION's adjustment factor of 
0.1 was used for TGS density estimates because TGS proposes to be well 
north and west of ION's westernmost 2012 survey lines no earlier than 
15-30 September through 31 October 2013. In comparison, ION proposed 
their program for 1 October through mid-December, and their actual 
program occurred in the Chukchi and Beaufort Seas from 20 October-9 
November, 2012. These periods overlap the majority of the period that 
TGS is expected to be operating at or near the westernmost seismic 
lines (no earlier than 15-30 September through October) between 
73[deg]-76[deg] N and 160[deg] W to 160[deg] E. Thus, ION's ``late 
season'' period coincides with TGS' proposed late fall season both in 
time and space relative to waters above 72[deg] N.
    The upper density estimates consisted of the averaged fall 
densities for more southern Chukchi waters by only (1) a smaller 
adjustment factor of 0.20 for gray whales (Table 4 of TGS' IHA 
application), and (2) by the same factor of 0.0 for fin, humpback, 
minke and killer whales, and harbor porpoise and ribbon and spotted 
seals as described above.

Additional Rationale for Adjusting Densities North of 72[deg] N

     No whale sightings have been reported in waters north of 
72[deg] N during the few recent vessel-based surveys conducted there 
that overlapped the southern or eastern part of the proposed TGS 
project area and season (Blees et al. 2010; Hartin et al. 2011; Cameron 
et al. 2012).
     The main fall migration corridor for bowheads reportedly 
occurs south of 72[deg] N (Quakenbush et al. 2010). However, satellite-
tagging studies indicate that at least some individual bowheads migrate 
generally west/southwest across the project area in waters above 
72[deg] N and west of Barrow during the fall migration from September-
November (Quakenbush 2007; LGL 2011; Quakenbush et al. 2012).
     The reported gray whale distribution in the Chukchi Sea 
normally does not extend much north of 72[deg] N during summer/fall 
(Jefferson et al. 2008). This northernmost peripheral boundary area is 
thus expected to have very low gray whale densities. Furthermore, most 
gray whales will have migrated south of the project area by fall (Rice 
and Wolman 1971; Allen and Angliss 2012).

Exposure Calculation Methods

    The approach used to calculate the estimated number of individuals 
of each marine mammal species potentially exposed to received levels of 
seismic impulse sound levels >=160 dB (rms) re 1 [mu]Pa during the 
proposed seismic project is described below.
    1. The area of water (in km\2\) ensonified to >=160 dB (rms) re 1 
[mu]Pa around the operating seismic source array on seismic lines as 
well as turns and transits between seismic lines was calculated for 
U.S. and international waters for waters shallower and deeper

[[Page 35525]]

than 200 m, and for waters north and south of 72[deg] N (Table 2). It 
was assumed for purposes of this estimation that the full seismic 
source array would be used during all seismic lines and during the 1-km 
run-in and 5-km run-out between seismic lines. In addition, it was 
assumed that a single 60 in\3\ airgun would be used during turns and 
transits between seismic lines. Ensonified waters were calculated as 
follows.
    2. A buffer was applied on both sides of the planned survey 
tracklines equivalent to the distances modeled for the proposed 3,280 
in\3\ seismic source array by JASCO in 2010 at three locations in the 
project area (Zykov et al. 2013). The buffer width corresponding to 
this 160 (rms) dB re 1 [mu]Pa isopleth varied with three water depth 
categories. Thus, survey tracklines located over waters 17-40 m deep 
were buffered by 8.5 km, those over waters 41-100 m deep were buffered 
by 9.9 km, and those over water depths of >100 m were buffered by 15 
km.

Table 2--Estimated Area (km\2\) Ensonified to >160 dB (rms) re 1 [mu]Pa by Seismic Impulses Along TGS' 2013 Proposed Seismic Lines and Turns in U.S. and
  International Waters of the Chukchi Sea. Ensonified Areas Assumed That the Full 3,280 in\3\ Array Operated Continuously on Survey Lines and That the
                         Single Mitigation Airgun (60 in\3\) Operated Continuously on Turns (and Transits) Between Survey Lines
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                           Above 72[deg] N     Below 72[deg] N    Water depth < 200   Water depth > 200     All       All     All lines
                                        ----------------------------------------          m                   m            lines     turns    and turns
                                                                                ------------------------------------------------------------------------
                                           Total     Turns     Total     Turns     Total               Total               Total     Total      Total
                                           lines     area      lines     area      lines     Turns     lines     Turns     lines     turns    ensonified
                                           area     (km\2\)    area     (km\2\)    area      area      area      area      area      area        area
                                          (km\2\)             (km\2\)             (km\2\)   (km\2\)   (km\2\)   (km\2\)   (km\2\)   (km\2\)    (km\2\)
--------------------------------------------------------------------------------------------------------------------------------------------------------
US.....................................     65477      1294     72974      1442    114858      2770     23594       466    138452      2736       141188
International..........................    115135      4200         0         0     45954      1676     69181      2524    115135      4200       119335
                                        ----------------------------------------------------------------------------------------------------------------
    Total..............................    180612      5494     72974      1442    160812      3946     92775      2990    253586      6936       260522
--------------------------------------------------------------------------------------------------------------------------------------------------------

    3. A smaller buffer was applied to both sides of turn lines between 
seismic lines equivalent to the measured distance to the 160 dB (rms) 
re 1 [mu]Pa isopleth of a single 60 in\3\ array as measured by JASCO. 
The associated area in km\2\ was calculated using Mysticetus\TM\ 
software. Mysticetus\TM\ identified water depths at 100-m intervals 
along the survey trackline using bathymetric data. At each 100-m 
interval, Mysticetus\TM\ applied one of the three aforementioned 160 dB 
(rms) re 1 [mu]Pa radius isopleths corresponding to that water depth. 
Overlapping areas were treated separately. The resulting World Geodetic 
System (WGS) 84 polygons were re-projected into North Pole 
Stereographic coordinates and the total area was calculated.
    4. Averaged densities of marine mammals (Table 3 in TGS' IHA 
application) were adjusted as applicable (Table 4 in TGS' IHA 
application) then multiplied by the area predicted to be ensonified to 
>=160 dB (rms) re 1 [mu]Pa. The procedure is outlined below.
     Because TGS expects to conduct seismic lines in U.S. 
Federal waters sometime between mid-July and mid-September in late 
summer and early fall, the proportion of U.S. Federal waters ensonified 
to >160 dB (rms) re 1 [mu]Pa was multiplied by the average of summer 
and fall densities reported from other studies (Table 3 in TGS' IHA 
application).
     Because TGS expects to conduct seismic lines in 
international waters starting in fall from mid-to-late September 
through October, the proportion of international waters ensonified to 
>160 dB (rms) re 1 [mu]Pa was multiplied by the average of fall 
densities reported from other studies (based nearly exclusively on 
surveys south of 72[deg] N since it is considered the best and only 
systematic data available for the region).
     The proportions of ensonified waters north and south of 
72[deg] N were also calculated for U.S. and international waters. 
Species-specific average summer-fall and fall densities associated with 
these depth categories were multiplied by the corresponding proportion 
and season.
     In addition, the proportions of ensonified waters where 
water depth along the seismic line was <200 m deep or >200 m deep were 
calculated. Species-specific average summer-fall and fall densities 
associated with these depth categories were multiplied by the 
corresponding proportion and season.
     Reported fall density estimates for gray, bowhead and 
beluga whales, and bearded and ringed seals were adjusted for ice-free 
waters N of 72[deg] N by multiplying reported fall densities for more 
southern Chukchi waters by low and high adjustment factors described 
above to provide a range of potential exposures.
    In a summary, estimated species exposures are calculated by 
multiplying seasonally (summer vs. fall) and spatially (above vs. below 
72[deg] N at various water depths) marine mammal density by the total 
ensonified areas with received levels higher than 160 dB re 1[mu]Pa 
(rms).

Potential Number of ``Take by Harassment''

    As stated earlier, the estimates of potential Level B takes of 
marine mammals by noise exposure are based on a consideration of the 
number of marine mammals that might be present during operations in the 
Chukchi Sea and the anticipated area exposed to those sound pressure 
levels (SPLs) above 160 dB re 1 [micro]Pa for impulse sources (seismic 
airgun during 2D seismic surveys).
    Some of the animals estimated to be exposed, particularly migrating 
bowhead whales, might show avoidance reactions before being exposed to 
sounds at the specified threshold levels. Thus, these calculations 
actually estimate the number of individuals potentially exposed to the 
specified sounds levels that would occur if there were no avoidance of 
the area ensonified to that level.
    Numbers of marine mammals that might be present and potentially 
taken are summarized in Table 3 based on calculation described above.

[[Page 35526]]



  Table 3--Estimates of the Possible Maximum Numbers of Marine Mammals
   Taken by Level B Harassment (Exposed to >=160 dB From Airgun Sound)
 During TGS' Proposed 2D Seismic Survey in the Chukchi Sea, July-October
                                  2013
------------------------------------------------------------------------
                                                  Level B      Percent
                    Species                        takes      population
------------------------------------------------------------------------
Bowhead whale.................................          794         7.53
Gray whale....................................        1,363         7.13
Fin whale.....................................            5         0.09
Humpback whale................................            5         0.53
Minke whale...................................            5         0.62
Beluga whale..................................          412        11.11
Killer whale..................................            5         1.59
Harbor porpoise...............................           36         0.07
Ringed seal...................................       30,000        14.36
Bearded seal..................................         6000         0.84
Spotted seal..................................          500         0.84
Ribbon seal...................................          100         0.20
------------------------------------------------------------------------

Estimated Take Conclusions

    Effects on marine mammals are generally expected to be restricted 
to avoidance of the area around the planned activities and short-term 
changes in behavior, falling within the MMPA definition of ``Level B 
harassment''.
    Cetaceans--The take calculation estimates suggest a total of 794 
bowhead whales may be exposed to sounds at or above 160 dB (rms) re 1 
[micro]Pa (Table 3). This number is approximately 7.53% of the Bering-
Chukchi-Beaufort (BCB) population of 10,545 assessed in 2001 (Allen and 
Angliss 2011) and is assuming to be increasing at an annual growth rate 
of 3.4% (Zeh and Punt 2005), which is supported by a 2004 population 
estimate of 12,631 by Koski et al. (2010). The total estimated number 
of gray and beluga whales that may be exposed to sounds from the 
activities ranges up to 1,363 and 412, respectively (Table 3). Fewer 
harbor porpoises are likely to be exposed to sounds during the 
activities. The small numbers of other whale species that may occur in 
the Chukchi Sea are unlikely to be present around the planned 
operations but chance encounters may occur. The few individuals would 
represent a very small proportion of their respective populations.
    Pinnipeds--Ringed seal is by far the most abundant species expected 
to be encountered during the planned operations. The best estimate of 
the numbers of ringed seals exposed to sounds at the specified received 
levels during the planned activities is 30,000, which represent up to 
14.36% of the Alaska population. Fewer individuals of other pinniped 
species are estimated to be exposed to sounds at Level B behavioral 
harassment level, also representing small proportions of their 
populations.
Negligible Impact and Small Numbers Analysis and Preliminary 
Determination
    As a preliminary matter, we typically include our negligible impact 
and small numbers analysis and determination under the same section 
heading of our Federal Register Notices. Despite co-locating these 
terms, we acknowledge that negligible impact and small numbers are 
distinct standards under the MMPA and treat them as such. The analysis 
presented below does not conflate the two standards; instead, each has 
been considered independently and we have applied the relevant factors 
to inform our negligible impact and small numbers determinations.
    NMFS has defined ``negligible impact'' in 50 CFR 216.103 as ``. . . 
an impact resulting from the specified activity that cannot be 
reasonably expected to, and is not reasonably likely to, adversely 
affect the species or stock through effects on annual rates of 
recruitment or survival.'' In making a negligible impact determination, 
NMFS considers a variety of factors, including but not limited to: (1) 
The number of anticipated mortalities; (2) the number and nature of 
anticipated injuries; (3) the number, nature, intensity, and duration 
of Level B harassment; and (4) the context in which the takes occur.
    No injuries or mortalities are anticipated to occur as a result of 
TGS' proposed 2013 open-water 2D seismic surveys in the Chukchi Sea, 
and none are proposed to be authorized. Additionally, animals in the 
area are not expected to incur hearing impairment (i.e., TTS or PTS) or 
non-auditory physiological effects. Takes will be limited to Level B 
behavioral harassment. Although it is possible that some individuals of 
marine mammals may be exposed to sounds from marine survey activities 
more than once, the expanse of these multi-exposures are expected to be 
less extensive since both the animals and the survey vessels will be 
moving constantly in and out of the survey areas.
    Most of the bowhead whales encountered will likely show overt 
disturbance (avoidance) only if they receive airgun sounds with levels 
>= 160 dB re 1 [mu]Pa. Odontocete reactions to seismic airgun pulses 
are usually assumed to be limited to shorter distances from the 
airgun(s) than are those of mysticetes, probably in part because 
odontocete low-frequency hearing is assumed to be less sensitive than 
that of mysticetes. However, at least when in the Canadian Beaufort Sea 
in summer, belugas appear to be fairly responsive to seismic energy, 
with few being sighted within 6-12 mi (10-20 km) of seismic vessels 
during aerial surveys (Miller et al. 2005). Belugas will likely occur 
in small numbers in the Chukchi Sea during the survey period and few 
will likely be affected by the survey activity.
    As noted, elevated background noise level from the seismic airgun 
reverberant field could cause acoustic masking to marine mammals and 
reduce their communication space. However, even though the decay of the 
signal is extended, the fact that pulses are separated by approximately 
10 seconds means that overall received levels at distance are expected 
to be much lower, thus resulting in less acoustic masking.
    Taking into account the mitigation measures that are planned, 
effects on marine mammals are generally expected to be restricted to 
avoidance of a limited area around TGS' proposed open-water activities 
and short-term changes in behavior, falling within the MMPA definition 
of ``Level B harassment''. The many reported cases of apparent 
tolerance by cetaceans of seismic exploration, vessel traffic, and some 
other human activities show that co-existence is possible. Mitigation 
measures such as controlled vessel speed, dedicated marine mammal 
observers, non-pursuit, and shut downs or power downs when marine 
mammals are seen within defined ranges will further reduce short-term 
reactions and minimize any effects on hearing sensitivity. In all 
cases, the effects are expected to be short-term, with no lasting 
biological consequence.
    Of the thirteen marine mammal species likely to occur in the 
proposed marine survey area, bowhead, fin, and humpback whales and 
ringed and bearded seals are listed as endangered or threatened under 
the ESA. These species are also designated as ``depleted'' under the 
MMPA. Despite these designations, the BCB stock of bowheads has been 
increasing at a rate of 3.4 percent annually for nearly a decade (Allen 
and Angliss 2010). Additionally, during the 2001 census, 121 calves 
were counted, which was the highest yet recorded. The calf count 
provides corroborating evidence for a healthy and increasing population 
(Allen and Angliss 2010). The occurrence of fin and humpback whales in 
the proposed marine survey areas is considered very rare. There is no 
critical habitat designated in the U.S. Arctic for the bowhead, fin, 
and humpback whales. The Alaska stock of bearded

[[Page 35527]]

seals, part of the Beringia distinct population segment (DPS), and the 
Arctic stock of ringed seals, have recently been listed by NMFS as 
threatened under the ESA. None of the other species that may occur in 
the project area are listed as threatened or endangered under the ESA 
or designated as depleted under the MMPA.
    Potential impacts to marine mammal habitat were discussed 
previously in this document (see the ``Anticipated Effects on Habitat'' 
section). Although some disturbance is possible to food sources of 
marine mammals, the impacts are anticipated to be minor enough as to 
not affect rates of recruitment or survival of marine mammals in the 
area. Based on the vast size of the Arctic Ocean where feeding by 
marine mammals occurs versus the localized area of the 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.
    The estimated takes proposed to be authorized represent 11.11% of 
the Eastern Chukchi Sea population of approximately 3,710 beluga 
whales, 1.59% of Aleutian Island and Bering Sea stock of approximately 
314 killer whales, 0.07% of Bering Sea stock of approximately 48,215 
harbor porpoises, 7.13% of the Eastern North Pacific stock of 
approximately 19,126 gray whales, 7.53% of the Bering-Chukchi-Beaufort 
population of 10,545 bowhead whales, 0.53% of the Western North Pacific 
stock of approximately 938 humpback whales, 0.09% of the Northeast 
Pacific stock of approximately 5,700 fin whales, and 0.62% of the 
Alaska stock of approximately 810 minke whales. The take estimates 
presented for ringed, bearded, spotted, and ribbon seals represent 
14.36, 2.47, 0.84, and 0.20% of U.S. Arctic stocks of each species, 
respectively. The mitigation and monitoring measures (described 
previously in this document) proposed for inclusion in the IHA (if 
issued) are expected to reduce even further any potential disturbance 
to marine mammals.
    In addition, no important feeding and reproductive areas are known 
in the vicinity of the TGS' proposed seismic surveys at the time the 
proposed surveys are to take place. No critical habitat of ESA-listed 
marine mammal species occurs in the Chukchi Sea.
    Based on the analysis contained herein of the likely effects of the 
specified activity on marine mammals and their habitat, and taking into 
consideration the implementation of the mitigation and monitoring 
measures, NMFS preliminarily finds that TGS' proposed 2013 open-water 
2D seismic surveys in the Chukchi Sea may result in the incidental take 
of small numbers of marine mammals, by Level B harassment only, and 
that the total taking from the marine surveys will have a negligible 
impact on the affected species or stocks.
Unmitigable Adverse Impact Analysis and Preliminary Determination
    NMFS has preliminarily determined that TGS' proposed 2013 open-
water 2D seismic surveys in the Chukchi Sea will not have an 
unmitigable adverse impact on the availability of species or stocks for 
taking for subsistence uses. This preliminary determination is 
supported by information contained in this document and TGS' POC. TGS 
has adopted a spatial and temporal strategy for its Chukchi Sea open-
water seismic surveys that should minimize impacts to subsistence 
hunters. Due to the timing of the project and the distance from the 
surrounding communities, it is anticipated to have no effects on spring 
harvesting and little or no effects on the occasional summer harvest of 
beluga whale, subsistence seal hunts (ringed and spotted seals are 
primarily harvested in winter while bearded seals are hunted during 
July-September in the Beaufort Sea), or the fall bowhead hunt.
    In addition, based on the measures described in TGS' POC, the 
proposed mitigation and monitoring measures (described earlier in this 
document), and the project design itself, NMFS has determined 
preliminarily that there will not be an unmitigable adverse impact on 
subsistence uses from TGS' 2013 open-water 2D seismic surveys in the 
Chukchi Sea.

Proposed Incidental Harassment Authorization

    This section contains a draft of the IHA itself. The wording 
contained in this section is proposed for inclusion in the IHA (if 
issued).
    (1) This Authorization is valid from July 15, 2013, through October 
31, 2013.
    (2) This Authorization is valid only for activities associated with 
open-water 2D seismic surveys and related activities in the Chukchi 
Sea. The specific areas where TGS' surveys will be conducted are within 
the Chukchi Sea, Alaska, as shown in Figure 1 of TGS' IHA application.
    (3)(a) The species authorized for incidental harassment takings, 
Level B harassment only, are: Beluga whales (Delphinapterus leucas); 
harbor porpoises (Phocoena phocoena); killer whales (Orcinus orca); 
bowhead whales (Balaena mysticetus); gray whales (Eschrichtius 
robustus); humpback whales (Megaptera novaeangliae); fin whales 
(Balaenoptera physalus); minke whales (B. acutorostrata); bearded seals 
(Erignathus barbatus); spotted seals (Phoca largha); ringed seals (P. 
hispida); and ribbon seals (P. fasciata).
    (3)(b) The authorization for taking by harassment is limited to the 
following acoustic sources and from the following activities:
    (i) 3,280 in\3\ airgun arrays and other acoustic sources for 2D 
open-water seismic surveys; and
    (ii) Vessel activities related to open-water seismic surveys listed 
in (i).
    (3)(c) The taking of any marine mammal in a manner prohibited under 
this Authorization must be reported within 24 hours of the taking to 
the Alaska Regional Administrator (907-586-7221) or his designee in 
Anchorage (907-271-3023), National Marine Fisheries Service (NMFS) and 
the Chief of the Permits and Conservation Division, Office of Protected 
Resources, NMFS, at (301) 427-8401, or his designee (301) 427-8418).
    (4) The holder of this Authorization must notify the Chief of the 
Permits and Conservation Division, Office of Protected Resources, at 
least 48 hours prior to the start of collecting seismic data (unless 
constrained by the date of issuance of this Authorization in which case 
notification shall be made as soon as possible).
    (5) Prohibitions
    (a) The taking, by incidental harassment only, is limited to the 
species listed under condition 3(a) above and by the numbers listed in 
Table 1 (attached). The taking by Level A harassment, injury or death 
of these species or the taking by harassment, injury or death of any 
other species of marine mammal is prohibited and may result in the 
modification, suspension, or revocation of this Authorization.
    (b) The taking of any marine mammal is prohibited whenever the 
required source vessel protected species observers (PSOs), required by 
condition 7(a)(i), are not onboard in conformance with condition 
7(a)(i) of this Authorization.
    (6) Mitigation
    (a) Establishing Exclusion and Disturbance Zones:
    (i) Establish and monitor with trained PSOs a preliminary exclusion 
zones for cetaceans surrounding the airgun array on the source vessel 
where the received level would be 180 dB (rms) re 1 [micro]Pa. For 
purposes of the field verification test, described in condition 
7(e)(i), these radii are estimated to be 2,200, 2,500, and 2,400 m from 
the seismic source for

[[Page 35528]]

the 3,280 in\3\ airgun array in water depths of 17-40, 40-100, and >100 
m, respectively. The 180-dB radius from the single 60 in\3\ airgun is 
estimated to be at 68 m from the source, regardless of water depth.
    (ii) Establish and monitor with trained PSOs a preliminary 
exclusion zones for pinnipeds surrounding the airgun array on the 
source vessel where the received level would be 190 dB (rms) re 1 
[micro]Pa. For purposes of the field verification test, described in 
condition 7(e)(i), these radii are estimated to be 930, 920, and 430 m 
from the seismic source for the 3,280 in\3\ airgun array in water 
depths of 17-40, 40-100, and >100 m, respectively. The 190-dB radius 
from the single 60 in\3\ airgun is estimated to be at 13 m from the 
source, regardless of water depth.
    (iii) Establish a zone of influence (ZOIs) for cetaceans and 
pinnipeds surrounding the airgun array on the source vessel where the 
received level would be 160 dB (rms) re 1 [micro]Pa. For purposes of 
the field verification test described in condition 7(e)(i), these radii 
are estimated to be 8,500, 9,900, and 15,000 m from the seismic source 
for the 3,280 in\3\ airgun array in water depths of 17-40, 40-100, and 
>100 m, respectively. The 160-dB radius from the single 60 in\3\ airgun 
is estimated to be at 1,500 m from the source.
    (iv) Immediately upon completion of data analysis of the field 
verification measurements required under condition 7(e)(i) below, the 
new 160-dB, 180-dB, and 190-dB marine mammal ZOIs and exclusion zones 
shall be established based on the sound source verification.
    (b) Vessel Movement Mitigation:
    (i) Avoid concentrations or groups of whales (2 or more 
individuals) by all vessels under the direction of TGS. Operators of 
support vessels should, at all times, conduct their activities at the 
maximum distance possible from such concentrations of whales.
    (ii) Vessels in transit shall be operated at speeds necessary to 
ensure no physical contact with whales occurs. If any vessel approaches 
within 1.6 km (1 mi) of observed bowhead whales, except when providing 
emergency assistance to whalers or in other emergency situations, the 
vessel operator will take reasonable precautions to avoid potential 
interaction with the bowhead whales by taking one or more of the 
following actions, as appropriate:
    (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.
    (iii) When weather conditions require, such as when visibility 
drops, adjust vessel speed accordingly to avoid the likelihood of 
injury to whales.
    (c) Mitigation Measures for Airgun Operations
    (i) Ramp-up:
    (A) A ramp up, following a complete shutdown of 10 minutes or more, 
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.
    (B) If a marine mammal(s) is sighted within the exclusion zone 
during the 30-minute watch prior to ramp up, ramp up will be delayed 
until the marine mammal(s) is sighted outside of the exclusion zone or 
the animal(s) is not sighted for at least 15-30 minutes: 15 minutes for 
small odontocetes (harbor porpoise) and pinnipeds, or 30 minutes for 
baleen whales and large odontocetes (including beluga and killer whales 
and narwhal).
    (C) 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.
    (D) The seismic operator and PSOs shall maintain records of the 
times when ramp-ups start and when the airgun arrays reach full power.
    (ii) Power-down/Shutdown:
    (A) The airgun array shall be immediately powered down whenever a 
marine mammal is sighted approaching close to or within the applicable 
exclusion zone of the full array, but is outside the applicable 
exclusion zone of the single mitigation airgun.
    (B) If a marine mammal is already within the exclusion zone when 
first detected, the airguns shall be powered down immediately.
    (C) Following a power-down, firing of the full airgun array shall 
not resume until the marine mammal has cleared the exclusion. The 
animal will be considered to have cleared the exclusion zone if it is 
visually observed to have left the exclusion zone of the full array, or 
has not been seen within the zone for 15 minutes (pinnipeds or small 
toothed whales) or 30 minutes (baleen whales or large toothed whales).
    (D) If a marine mammal is sighted within or about to enter the 190 
or 180 dB (rms) applicable exclusion zone of the single mitigation 
airgun, the airgun array shall be shutdown.
    (E) Firing of the full airgun array or the mitigation gun shall not 
resume until the marine mammal has cleared the exclusion zone of the 
full array or mitigation gun, respectively. The animal will be 
considered to have cleared the exclusion zone as described above under 
ramp up procedures.
    (iii) Poor Visibility Conditions:
    (A) If during foggy conditions, heavy snow or rain, or darkness, 
the full 180 dB exclusion zone is not visible, the airguns cannot 
commence a ramp-up procedure from a full shut-down.
    (B) If one or more airguns have been operational before nightfall 
or before the onset of poor visibility conditions, they can remain 
operational throughout the night or poor visibility conditions. In this 
case ramp-up procedures can be initiated, even though the exclusion 
zone may not be visible, on the assumption that marine mammals will be 
alerted by the sounds from the single airgun and have moved away.
    (iv) Use of a Small-Volume Airgun during Turns and Transits
    (A) Throughout the seismic survey, particularly during turning 
movements, and short transits, TGS will employ the use of a small-
volume airgun (i.e., 60 in\3\ ``mitigation airgun'') to deter marine 
mammals from being within the immediate area of the seismic operations. 
The mitigation airgun would be operated at approximately one shot per 
minute and would not be operated for longer than three hours in 
duration (turns may last two to three hours for the proposed project) 
during daylight hours. In cases when the next start-up after the turn 
is expected to be during lowlight or low visibility, continuous 
operation of mitigation airgun is permitted.
    (B) During turns or brief transits (e.g., less than three hours) 
between seismic tracklines, one mitigation airgun will continue 
operating. The ramp-up procedure will still be followed when increasing 
the source levels from one airgun to the full airgun array. However, 
keeping one airgun firing will avoid the prohibition of a ``cold 
start'' during darkness or other periods of poor visibility. Through 
the use of this approach, seismic surveys using the full array may 
resume without the 30

[[Page 35529]]

minute observation period of the full exclusion zone required for a 
``cold start''. PSOs will be on duty whenever the airguns are firing 
during daylight, during the 30 minute periods prior to ramp-ups.
    (d) Mitigation Measures for Subsistence Activities:
    (i) For the purposes of reducing or eliminating conflicts between 
subsistence whaling activities and TGS' survey program, the holder of 
this Authorization will participate with other operators in the 
Communication and Call Centers (Com-Center) Program. The Com-Centers 
will be operated 24 hours/day during the 2013 fall subsistence bowhead 
whale hunt.
    (ii) The appropriate Com-Center shall be notified if there is any 
significant change in plans.
    (iii) Upon notification by a Com-Center operator of an at-sea 
emergency, the holder of this Authorization shall provide such 
assistance as necessary to prevent the loss of life, if conditions 
allow the holder of this Authorization to safely do so.
    (7) Monitoring:
    (a) Vessel-based Visual Monitoring:
    (i) Vessel-based visual monitoring for marine mammals shall be 
conducted by NMFS-approved protected species observers (PSOs) 
throughout the period of survey activities.
    (ii) PSOs shall be stationed aboard the seismic survey vessel and 
supporting vessel through the duration of the surveys.
    (iii) A sufficient number of PSOs shall be onboard the survey 
vessel to meet the following criteria:
    (A) 100% monitoring coverage during all periods of survey 
operations in daylight;
    (B) maximum of 4 consecutive hours on watch per PSO; and
    (C) maximum of 12 hours of watch time per day per PSO.
    (iv) The vessel-based marine mammal monitoring shall provide the 
basis for real-time mitigation measures as described in (6)(c) above.
    (v) Results of the vessel-based marine mammal monitoring shall be 
used to calculate the estimation of the number of ``takes'' from the 
marine surveys.
    (b) Protected Species Observers and Training
    (i) PSO teams shall consist of Inupiat observers and NMFS-approved 
field biologists.
    (ii) Experienced field crew leaders shall supervise the PSO teams 
in the field. New PSOs shall be paired with experienced observers to 
avoid situations where lack of experience impairs the quality of 
observations.
    (iii) Crew leaders and most other biologists serving as observers 
in 2013 shall be individuals with experience as observers during recent 
seismic or shallow hazards monitoring projects in Alaska, the Canadian 
Beaufort, or other offshore areas in recent years.
    (iv) Resumes for PSO candidates shall be provided to NMFS for 
review and acceptance of their qualifications. Inupiat observers shall 
be experienced in the region and familiar with the marine mammals of 
the area.
    (v) All observers shall complete a NMFS-approved observer training 
course designed to familiarize individuals with monitoring and data 
collection procedures. The training course shall be completed before 
the anticipated start of the 2013 open-water season. The training 
session(s) shall be conducted by qualified marine mammalogists with 
extensive crew-leader experience during previous vessel-based 
monitoring programs.
    (vi) Training for both Alaska native PSOs and biologist PSOs shall 
be conducted at the same time in the same room. There shall not be 
separate training courses for the different PSOs.
    (vii) Crew members should not be used as primary PSOs because they 
have other duties and generally do not have the same level of 
expertise, experience, or training as PSOs, but they could be stationed 
on the fantail of the vessel to observe the near field, especially the 
area around the airgun array and implement a power down or shutdown if 
a marine mammal enters the safety zone (or exclusion zone).
    (viii) If crew members are to be used as PSOs, they shall go 
through some basic training consistent with the functions they will be 
asked to perform. The best approach would be for crew members and PSOs 
to go through the same training together.
    (ix) PSOs shall be trained using visual aids (e.g., videos, 
photos), to help them identify the species that they are likely to 
encounter in the conditions under which the animals will likely be 
seen.
    (x) TGS shall train its PSOs to follow a scanning schedule that 
consistently distributes scanning effort according to the purpose and 
need for observations. All PSOs should follow the same schedule to 
ensure consistency in their scanning efforts.
    (xi) PSOs shall be trained in documenting the behaviors of marine 
mammals. PSOs should simply record the primary behavioral state (i.e., 
traveling, socializing, feeding, resting, approaching or moving away 
from vessels) and relative location of the observed marine mammals.
    (c) Marine Mammal Observation Protocol
    (i) PSOs shall watch for marine mammals from the best available 
vantage point on the survey vessels, typically the bridge.
    (ii) Observations by the PSOs on marine mammal presence and 
activity shall begin a minimum of 30 minutes prior to the estimated 
time that the seismic source is to be turned on and/or ramped-up.
    (iii) PSOs shall scan systematically with the unaided eye and 7 x 
50 reticle binoculars, supplemented with 20 x 60 image-stabilized Zeiss 
Binoculars or Fujinon 25 x 150 ``Big-eye'' binoculars, and night-vision 
equipment when needed.
    (iv) Personnel on the bridge shall assist the marine mammal 
observer(s) in watching for marine mammals.
    (v) PSOs aboard the marine survey vessel shall give particular 
attention to the areas within the marine mammal exclusion zones around 
the source vessel, as noted in (6)(a)(i) and (ii). They shall avoid the 
tendency to spend too much time evaluating animal behavior or entering 
data on forms, both of which detract from their primary purpose of 
monitoring the exclusion zone.
    (vi) Monitoring shall consist of recording of the following 
information:
    (A) The species, group size, age/size/sex categories (if 
determinable), the general behavioral activity, heading (if 
consistent), bearing and distance from seismic vessel, sighting cue, 
behavioral pace, and apparent reaction of all marine mammals seen near 
the seismic vessel and/or its airgun array (e.g., none, avoidance, 
approach, paralleling, etc);
    (B) the time, location, heading, speed, and activity of the vessel 
(shooting or not), along with sea state, visibility, cloud cover and 
sun glare at (I) any time a marine mammal is sighted (including 
pinnipeds hauled out on barrier islands), (II) at the start and end of 
each watch, and (III) during a watch (whenever there is a change in one 
or more variable);
    (C) the identification of all vessels that are visible within 5 km 
of the seismic vessel whenever a marine mammal is sighted and the time 
observed;
    (D) any identifiable marine mammal behavioral response (sighting 
data should be collected in a manner that will not detract from the 
PSO's ability to detect marine mammals);
    (E) any adjustments made to operating procedures; and
    (F) visibility during observation periods so that total estimates 
of take can be corrected accordingly.
    (vii) Distances to nearby marine mammals will be estimated with 
binoculars (Fujinon 7 x 50 binoculars)

[[Page 35530]]

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.
    (viii) PSOs shall understand the importance of classifying marine 
mammals as ``unknown'' or ``unidentified'' if they cannot identify the 
animals to species with confidence. In those cases, they shall note any 
information that might aid in the identification of the marine mammal 
sighted. For example, for an unidentified mysticete whale, the 
observers should record whether the animal had a dorsal fin.
    (ix) Additional details about unidentified marine mammal sightings, 
such as ``blow only'', mysticete with (or without) a dorsal fin, ``seal 
splash'', etc., shall be recorded.
    (x) When a marine mammal is seen approaching or within the 
exclusion zone applicable to that species, the marine survey crew shall 
be notified immediately so that mitigation measures described in (6) 
can be promptly implemented.
    (xi) TGS shall use the best available technology to improve 
detection capability during periods of fog and other types of inclement 
weather. Such technology might include night-vision goggles or 
binoculars as well as other instruments that incorporate infrared 
technology.
(d) Field Data-Recording and Verification
    (A) PSOs aboard the vessels shall maintain a digital log of seismic 
surveys, noting the date and time of all changes in seismic activity 
(ramp-up, power-down, changes in the active seismic source, shutdowns, 
etc.) and any corresponding changes in monitoring radii in a software 
spreadsheet.
    (B) PSOs shall utilize standardized format to record all marine 
mammal observations and mitigation actions (seismic source power-downs, 
shut-downs, and ramp-ups).
    (C) Information collected during marine mammal observations shall 
include the following:

(I) Vessel speed, position, and activity
(II) Date, time, and location of each marine mammal sighting
(III) Number of marine mammals observed, and group size, sex, and age 
categories
(IV) Observer's name and contact information
(V) Weather, visibility, and ice conditions at the time of observation
(VI) Estimated distance of marine mammals at closest approach
(VII) Activity at the time of observation, including possible 
attractants present
(VIII) Animal behavior
(IX) Description of the encounter
(X) Duration of encounter
(XI) Mitigation action taken

    (D) Data shall be recorded directly into handheld computers or as a 
back-up, transferred from hard-copy data sheets into an electronic 
database.
    (E) A system for quality control and verification of data shall be 
facilitated by the pre-season training, supervision by the lead PSOs, 
in-season data checks, and shall be built into the software.
    (F) Computerized data validity checks shall also be conducted, and 
the data shall be managed in such a way that it is easily summarized 
during and after the field program and transferred into statistical, 
graphical, or other programs for further processing.
(e) Passive Acoustic Monitoring
    (i) Sound Source Measurements: Using a hydrophone system, the 
holder of this Authorization is required to conduct sound source 
verification tests for seismic airgun array(s) that are involved in the 
open-water seismic surveys.
    (A) Sound source verification shall consist of distances where 
broadside and endfire directions at which broadband received levels 
reach 190, 180, 170, and 160 dB (rms) re 1 [mu]Pa for the airgun 
array(s). The configurations of airgun arrays shall include at least 
the full array and the operation of a single source that will be used 
during power downs.
    (B) The test results shall be reported to NMFS within 5 days of 
completing the test.
    (ii) Real-time Passive Acoustic Monitoring (PAM).
    (A) TGS shall conduct real-time passive acoustic monitoring by 
NMFS-approved passive acoustic monitor(s) using a towed hydrophone 
array from the support vessel throughout the open-water seismic 
surveys.
    (B) Passive Acoustic Operator(s) and Monitor(s):
    (I) Design and initial setup of PAM apparatus (including hardware 
and software) shall be done by experienced bioacoustician(s) with field 
experience in marine mammal passive acoustic monitoring and signal 
processing.
    (II) Passive acoustic monitor(s) shall undergo basic training on 
PAM, and be able to operate independently once the PAM apparatus is 
set-up.
    (III) Resumes for the bioacoustician(s) and passive acoustic 
monitor(s) candidates shall be provided to NMFS for review and 
acceptance of their qualifications.
    (C) Specific sensor design and noise filters shall be used to 
maximize the system's ability to detect low frequency bowhead whales. 
To ensure the effectiveness of real-time PAM with a towed hydrophone 
array, the following requirements for PAM design and procedures are 
required:
    (I) Limit towing speeds to 4-6 knots. Reduce speed appropriately, 
or change direction if necessary, so that if bowhead whales are 
detected so that bearing can be obtained. If greater speeds are 
necessary, slow down every 20-30 minutes to listen for animal calls for 
at least 5-10 minutes.
    (II) Maintain a separation distance of at least several hundred 
meters (preferable more) from the seismic survey vessel.
    (D) Best efforts shall be made without compromising data collection 
to localize vocalizing marine mammals.
    (I) Use a signal conditioning system (i.e. filter and match signal 
gains) to allow software to effectively estimate bearings and/or 
localize.
    (II) Use software designed exclusively for monitoring, localizing 
and plotting marine mammal calls.
    (III) Design the sampling software to optimize overlap between 
monitoring the 180 and 160 dB isopleths.
    (IV) Allow the support vessel to deviate from designated track-
lines by 25-30 degrees (for brief periods) so that left/right ambiguity 
can be resolved if needed.
    (8) Data Analysis and Presentation in Reports:
    (a) Estimation of potential takes or exposures shall be improved 
for times with low visibility (such as during fog or darkness) through 
interpolation or possibly using a probability approach. Those data 
could be used to interpolate possible takes during periods of 
restricted visibility.
    (b) To better assess impacts to marine mammals, data analysis shall 
be separated into periods when a seismic airgun array (or a single 
mitigation airgun) is operating and when it is not. Final report to 
NMFS should summarize and plot:
    (i) Data for periods when a seismic array is active and when it is 
not; and
    (ii) The respective predicted received sound conditions over fairly 
large areas (tens of km) around operations.
    (c) To help evaluate the effectiveness of PSOs and more effectively 
estimate take, if appropriate data are available, TGS shall perform 
analysis of sightability curves (detection functions) for distance-
based analyses.

[[Page 35531]]

    (d) To better understand the potential effects of oil and gas 
activities on marine mammals and to facilitate integration among 
companies and other researchers, the following data should be obtained 
and provided electronically in the 90-day report:
    (i) the location and time of each vessel-based sighting or acoustic 
detection;
    (ii) position of the sighting or acoustic detection relative to 
ongoing operations (i.e., distance from sightings to seismic operation, 
etc.), if known;
    (iii) the nature of activities at the time (e.g., seismic on/off);
    (iv) any identifiable marine mammal behavioral response (sighting 
data should be collected in a manner that will not detract from the PSO 
of passive acoustic monitor's ability to detect marine mammals); and
    (v) adjustments made to operating procedures.
    (e) TGS shall provide useful summaries and interpretations of 
results of the various elements of the monitoring results, which shall 
include a clear timeline and spatial (map) representation/summary of 
operations and important observations. Any and all mitigation measures 
(e.g., vessel course deviations for animal avoidance, operational shut 
down) should be summarized. Additionally, an assessment of the efficacy 
of monitoring methods should be provided.
    (f) TGS shall collaborate with other organizations operating in the 
Chukchi Sea and share visual and acoustic data to improve understanding 
of impacts from single and multiple operations and efficacy of 
mitigation measures.
    (9) Reporting:
    (a) Sound Source Verification Report: A report on the preliminary 
results of the sound source verification measurements, including the 
measured 190, 180, and 160 dB (rms) radii of the airgun sources and 
other acoustic survey equipment, shall be submitted within 14 days 
after collection of those measurements at the start of the field 
season. This report will specify the distances of the exclusion zones 
that were adopted for the survey.
    (b) Throughout the survey program, PSOs shall prepare a report each 
day or at such other intervals, summarizing the recent results of the 
monitoring program. The reports shall summarize the species and numbers 
of marine mammals sighted. These reports shall be provided to NMFS.
    (c) Seismic Vessel Monitoring Program: A draft report will be 
submitted to the Director, Office of Protected Resources, NMFS, within 
90 days after the end of TGS' 2013 open-water seismic surveys in the 
Chukchi Sea. The report will describe in detail:
    (i) summaries of monitoring effort (e.g., total hours, total 
distances, and marine mammal distribution through the study period, 
accounting for sea state and other factors affecting visibility and 
detectability of marine mammals);
    (ii) analyses of the effects of various factors influencing 
detectability of marine mammals (e.g., sea state, number of observers, 
and fog/glare);
    (iii) species composition, occurrence, and distribution of marine 
mammal sightings, including date, water depth, numbers, age/size/gender 
categories (if determinable), group sizes, and ice cover;
    (iv) to better assess impacts to marine mammals, data analysis 
should be separated into periods when an airgun array (or a single 
airgun) is operating and when it is not. Final and comprehensive 
reports to NMFS should summarize and plot: (A) Data for periods when a 
seismic array is active and when it is not; and (B) The respective 
predicted received sound conditions over fairly large areas (tens of 
km) around operations.
    (v) sighting rates of marine mammals during periods with and 
without airgun activities (and other variables that could affect 
detectability), such as: (A) Initial sighting distances versus airgun 
activity state; (B) closest point of approach versus airgun activity 
state; (C) observed behaviors and types of movements versus airgun 
activity state; (D) numbers of sightings/individuals seen versus airgun 
activity state; (E) distribution around the survey vessel versus airgun 
activity state; and (F) estimates of take by harassment.
    (vi) reported results from all hypothesis tests should include 
estimates of the associated statistical power when practicable.
    (vii) estimate and report uncertainty in all take estimates. 
Uncertainty could be expressed by the presentation of confidence 
limits, a minimum-maximum, posterior probability distribution, etc.; 
the exact approach would be selected based on the sampling method and 
data available.
    (viii) The report should clearly compare authorized takes to the 
level of actual estimated takes.
    (d) The draft report shall be subject to review and comment by 
NMFS. Any recommendations made by NMFS must be addressed in the final 
report prior to acceptance by NMFS. The draft report will be considered 
the final report for this activity under this Authorization if NMFS has 
not provided comments and recommendations within 90 days of receipt of 
the draft report.
    (10)(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 (Level A harassment), serious injury 
or mortality (e.g., ship-strike, gear interaction, and/or 
entanglement), TGS shall immediately cease survey operations and 
immediately report the incident to the Supervisor of the Incidental 
Take Program, Permits and Conservation Division, Office of Protected 
Resources, NMFS, at 301-427-8401 and/or by email to 
Jolie.Harrison@noaa.gov and Shane.Guan@noaa.gov and the Alaska Regional 
Stranding Coordinators (Aleria.Jensen@noaa.gov and 
Barbara.Mahoney@noaa.gov). 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);
    (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 TGS to 
determine what is necessary to minimize the likelihood of further 
prohibited take and ensure MMPA compliance. TGS may not resume their 
activities until notified by NMFS via letter, email, or telephone.
    (b) In the event that TGS 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), 
TGS will immediately report the incident to the Supervisor of the 
Incidental Take Program, Permits and Conservation Division, Office of 
Protected Resources, NMFS, at 301-427-8401, and/or by email to 
Jolie.Harrison@noaa.gov and Shane.Guan@noaa.gov and the NMFS Alaska 
Stranding Hotline (1-877-925-

[[Page 35532]]

7773) and/or by email to the Alaska Regional Stranding Coordinators 
(Aleria.Jensen@noaa.gov and Barabara.Mahoney@noaa.gov). The report must 
include the same information identified in Condition 10(a) above. 
Activities may continue while NMFS reviews the circumstances of the 
incident. NMFS will work with TGS to determine whether modifications in 
the activities are appropriate.
    (c) In the event that TGS 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 Condition 3 
of this Authorization (e.g., previously wounded animal, carcass with 
moderate to advanced decomposition, or scavenger damage), TGS shall 
report the incident to the Supervisor of the Incidental Take Program, 
Permits and Conservation Division, Office of Protected Resources, NMFS, 
at 301-427-8401, and/or by email to Jolie.Harrison@noaa.gov and 
Shane.Guan@noaa.gov and the NMFS Alaska Stranding Hotline (1-877-925-
7773) and/or by email to the Alaska Regional Stranding Coordinators 
(Aleria.Jensen@noaa.gov and Barbara.Mahoney@noaa.gov), within 24 hours 
of the discovery. TGS shall provide photographs or video footage (if 
available) or other documentation of the stranded animal sighting to 
NMFS and the Marine Mammal Stranding Network. TGS can continue its 
operations under such a case.
    (11) Activities related to the monitoring described in this 
Authorization do not require a separate scientific research permit 
issued under section 104 of the Marine Mammal Protection Act.
    (12) The Plan of Cooperation outlining the steps that will be taken 
to cooperate and communicate with the native communities to ensure the 
availability of marine mammals for subsistence uses, must be 
implemented.
    (13) This Authorization may be modified, suspended or withdrawn if 
the holder fails to abide by the conditions prescribed herein or if the 
authorized taking is having more than a negligible impact on the 
species or stock of affected marine mammals, or if there is an 
unmitigable adverse impact on the availability of such species or 
stocks for subsistence uses.
    (14) A copy of this Authorization and the Incidental Take Statement 
must be in the possession of each seismic vessel operator taking marine 
mammals under the authority of this Incidental Harassment 
Authorization.
    (15) TGS is required to comply with the Terms and Conditions of the 
Incidental Take Statement corresponding to NMFS' Biological Opinion.

Endangered Species Act (ESA)

    The bowhead, fin, and humpback whales and ringed and bearded seals 
are the only marine mammal species currently listed as endangered or 
threatened under the ESA that could occur during TGS' proposed seismic 
surveys during the Arctic open-water season. NMFS' Permits and 
Conservation Division has initiated consultation with NMFS' Protected 
Resources Division under section 7 of the ESA on the issuance of an IHA 
to TGS under section 101(a)(5)(D) of the MMPA for this activity. 
Consultation will be concluded prior to a determination on the issuance 
of an IHA.

National Environmental Policy Act (NEPA)

    NMFS is currently preparing an Environmental Assessment, pursuant 
to NEPA, to determine whether or not this proposed activity may have a 
significant effect on the human environment. This analysis will be 
completed prior to the issuance or denial of the IHA.

Proposed Authorization

    As a result of these preliminary determinations, NMFS proposes to 
authorize the take of marine mammals incidental to TGS' 2013 open-water 
2D seismic surveys in the Alaskan Chukchi Sea, provided the previously 
mentioned mitigation, monitoring, and reporting requirements are 
incorporated.

    Dated: June 6, 2013.
Donna S. Wieting,
Director, Office of Protected Resources, National Marine Fisheries 
Service.
[FR Doc. 2013-13988 Filed 6-11-13; 8:45 am]
BILLING CODE 3510-22-P