[Federal Register Volume 71, Number 93 (Monday, May 15, 2006)]
[Notices]
[Pages 27997-28013]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 06-4520]


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DEPARTMENT OF COMMERCE

National Oceanic and Atmospheric Administration

[I.D. 050306A]


Small Takes of Marine Mammals Incidental to Specified Activities; 
Marine Geophysical Survey of the Western Canada Basin, Chukchi 
Borderland and Mendeleev Ridge, Arctic Ocean, July-August, 2006

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

ACTION: Notice; receipt of application and proposed incidental take 
authorization; request for comments.

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SUMMARY: NMFS has received an application from the University of Texas 
at Austin Institute for Geophysics (UTIG) for an Incidental Harassment 
Authorization (IHA) to take small numbers of marine mammals, by 
harassment, incidental to conducting a marine seismic survey in the 
Arctic Ocean from approximately July 15 - August 25, 2006. Pursuant to 
the Marine Mammal Protection Act (MMPA), NMFS is requesting comments on 
its proposal to issue an authorization to incidentally take, by 
harassment, small numbers of several species of marine mammals during 
the seismic survey.

DATES: Comments and information must be received no later than June 14, 
2006.

ADDRESSES: Comments on the application should be addressed to Steve 
Leathery, Chief, Permits, Conservation and Education Division, Office 
of Protected Resources, National Marine Fisheries Service, 1315 East-
West Highway, Silver Spring, MD 20910-3225. The mailbox address for 
providing email comments is [email protected]. NMFS is not 
responsible for e-mail comments sent to addresses other than the one 
provided here. Comments sent via e-mail, including all attachments, 
must not exceed a 10-megabyte file size.
    A copy of the application containing a list of the references used 
in this document may be obtained by writing to the address specified 
above, telephoning the contact listed below (see FOR FURTHER 
INFORMATION CONTACT), or visiting the internet at: http://www.nmfs.noaa.gov/pr/permits/incidental.htm.
    Documents cited in this notice may be viewed, by appointment, 
during regular business hours, at the aforementioned address.

FOR FURTHER INFORMATION CONTACT: Jolie Harrison, Office of Protected 
Resources, NMFS, (301) 713-2289, ext 166.

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 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 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, and that 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 United States can apply for an authorization 
to incidentally take small numbers of marine mammals by harassment. 
Except with respect to certain activities not pertinent here, the MMPA 
defines ``harassment'' as:
    any act of pursuit, torment, or annoyance which (i) has the 
potential to injure a marine mammal or marine mammal stock in the 
wild [Level A harassment]; or (ii) has the potential to disturb a 
marine mammal or marine mammal stock in the wild by causing 
disruption of behavioral patterns, including, but not limited to, 
migration, breathing, nursing, breeding, feeding, or sheltering 
[Level B harassment].
    Section 101(a)(5)(D) establishes a 45-day time limit for NMFS 
review of an application followed by a 30-day public notice and comment 
period on any proposed authorizations for the incidental harassment of 
marine mammals. Within 45 days of the close of the comment period, NMFS 
must either issue or deny issuance of the authorization.

Summary of Request

    On March 8, 2006, NMFS received an application from UTIG for the 
taking, by

[[Page 27998]]

harassment, of several species of marine mammals incidental to 
conducting, with research funding from the National Science Foundation 
(NSF), a marine seismic survey in the Western Canada Basin, Chukchi 
Borderland and Mendeleev Ridge of the Arctic Ocean during July through 
August, 2006. The seismic survey will be operated in conjunction with a 
sediment coring project, which will obtain data regarding crustal 
structure. The purpose of the proposed study is to collect seismic 
reflection and refraction data and sediment cores that reveal the 
crustal structure and composition of submarine plateaus in the western 
Amerasia Basin in the Arctic Ocean. Past studies have led many 
researchers to support the idea that the Amerasia Basin opened about a 
pivot point near the Mackenzie Delta. However, the crustal character of 
the Chukchi Borderlands could determine whether that scenario is 
correct, or whether more complicated tectonic scenarios must be devised 
to explain the presence of the Amerasia Basin. These data will assist 
in the determination of the tectonic evolution of the Amerasia Basin 
and Canada Basin which is fundamental to such basic concerns as sea 
level fluctuations and paleoclimate in the Mesozoic era.

Description of the Activity

    The Healy, a U.S. Coast Guard (USCG) Cutter ice-breaker, will 
rendezvous with the science party off Barrow on or around 15 July. The 
Healy will then sail north and arrive at the beginning of the seismic 
survey, which will start >150 km (93 mi) north of Barrow. The cruise 
will last for approximately 40 days, and it is estimated that the total 
seismic survey time will be approximately 30 days depending on ice 
conditions. Seismic survey work is scheduled to terminate west of 
Barrow about 25 August. The vessel will then sail south to Nome where 
the science party will disembark.
    The seismic survey and coring activities will take place in the 
Arctic Ocean. The overall area within which the seismic survey will 
occur is located approximately between 71[deg]36' and 79[deg]25' N., 
and between 151[deg]57' E. and 177[deg]24' E. The bulk of the seismic 
survey will not be conducted in any country's territorial waters. The 
survey will occur within the Exclusive Economic Zone (EEZ) of the U.S. 
for approximately 563 km.
    The Healy will use a portable Multi-Channel Seismic (MCS) system to 
conduct the seismic survey. A cluster of eight airguns will be used as 
the energy source during most of the cruise, especially in deep water 
areas. The airgun array will have four 500-in\3\ Bolt airguns and four 
210-in\3\ G. guns for a total discharge volume of 2840 in\3\. In 
shallow water, occurring during the first and last portions of the 
cruise, a four 105 in\3\ GI gun array with a total discharge volume of 
420 in\3\ will be used. Other sound sources (see below) will also be 
employed during the cruise. The seismic operations during the survey 
will be used to obtain information on the history of the ridges and 
basins that make up the Arctic Ocean.
    The Healy will also tow a hydrophone streamer 100-150 m (328-492 
ft) behind the ship, depending on ice conditions. The hydrophone 
streamer will be up to 200 m (656 ft) long. As the source operates 
along the survey lines, the hydrophone receiving system will receive 
and record the returning acoustic signals. In addition to the 
hydrophone streamer, sea ice seismometers (SIS) will be deployed on ice 
floes ahead of the ship using a vessel-based helicopter, and then 
retrieved from behind the ship once it has passed the SIS locations. 
SISs will be deployed as much as 120 km (74 mi) ahead of the ship, and 
recovered when as much as 120 km (74 mi) behind the ship. The 
seismometers will be placed on top of ice floes with a hydrophone 
lowered into the water through a small hole drilled in the ice. These 
instruments will allow seismic refraction data to be collected in the 
heavily ice-covered waters of the region.
    The program will consist of a total of approximately 3625 km (2252 
mi) of surveys, not including transits when the airguns are not 
operating, plus scientific coring at least seven locations. Water 
depths within the study area are 40-3858 m (131-12,657 ft). Little more 
than 8 percent of the survey (approximately 300 km (186 mi)) will occur 
in water depths <100 m (328 ft), 23 percent of the survey 
(approximately 838 km (520 mi)) will be conducted in water 100-1000 m 
(328-3280 ft) deep, and most (69 percent) of the survey (approximately 
2486 km (1,544 mi)) will occur in water deeper than 1000 m (3280 ft). 
There will be additional seismic operations associated with airgun 
testing, start up, and repeat coverage of any areas where initial data 
quality is sub-standard. In addition to the airgun array, a multibeam 
sonar and sub-bottom profiler will be used during the seismic profiling 
and continuously when underway. A pinger may be used during coring to 
help direct the core bit.
    The coring operations will be conducted in conjunction with the 
seismic study from the Healy. Seismic operations will be suspended 
while the USCG Healy is on site for coring. Several more coring sites 
may be identified and sampled depending on the ability to deploy SISs 
given ice and weather conditions. The plan is to extract one core from 
six of the seven identified sample locations along the seismic survey, 
and two cores at the last site on the Chukchi Cap. The coring system to 
be used is a piston corer that is lowered to the sea floor via a deep 
sea winch. Coring is expected to occur in 400-4000-m (1,312-13,120-ft) 
water depths. The piston corer recovers a sample in PVC tubes of 10 cm 
(3.9-in) diameter. Most of the cores will be approximately 
(approximately) 5-10 m long (16.4-32.8 ft); maximum possible length 
will be approximately 24 m (79 ft). The core is designed to leave 
nothing in the ocean after recovery.

Vessel Specifications

    The Healy has a length of 128 m (420 ft), a beam of 25 m (82 ft), 
and a full load draft of 8.9 m (29 ft). The Healy iscapable of 
traveling at 5.6 km/h (3 knots) through 1.4 m (4.6 ft) of ice. A 
``Central Power Plant'', four Sultzer 12Z AU40S diesel generators, 
provides electric power for propulsion and ship's services through a 60 
Hz, 3-phase common bus distribution system. Propulsion power is 
provided by two electric AC Synchronous, 11.2 MW drive motors, fed from 
the common bus through a Cycloconverter system, that turn two fixed-
pitch, four-bladed propellers. The operation speed during seismic 
acquisition is expected to be approximately 6.5 km/h (3.5 knots). When 
not towing seismic survey gear or breaking ice, the Healy cruises at 22 
km/h (12 knots) and has a maximum speed of 31.5 km/h (17 knots). It has 
a normal operating range of about 29,650 km (18,423 mi) at 23.2 km/hr 
(12.5 knots).

Seismic Source Description

    A portable MCS system will be installed on the Healy for this 
cruise. The source vessel will tow along predetermined lines one of two 
different airgun arrays (an 8-airgun array with a total discharge 
volume of 2840 in\3\ or a four GI gun array with a total discharge 
volume of 420 in3), as well as a hydrophone streamer. Seismic pulses 
will be emitted at intervals of approximately 60 s and recorded at a 2 
ms sampling rate. The 60-second spacing corresponds to a shot interval 
of approximately 120 m (394 t) at the anticipated typical cruise speed.
    As the airgun array is towed along the survey line, the towed 
hydrophone array receives the reflected signals and transfers the data 
to the on-board

[[Page 27999]]

processing system. The SISs will store returning signals on an internal 
datalogger and also relay them in real-time to the Healy via a radio 
transmitter, where they will be recorded and processed.
    The 8-airgun array will be configured as a four-G. gun cluster with 
a total discharge volume of 840 in\3\ and a four Bolt airgun cluster 
with a total discharge volume of 2000 in\3\. The source output is from 
246-253 dB re 1 microPa m. The two clusters are four meters apart. The 
clusters will be operated simultaneously for a total discharge volume 
of 2840 in\3\. The 4-GI gun array will be configured the same as the 
four G. gun portion of the 8-airgun array. The energy source (source 
level 239-245 dB re 1 microPa m) will be towed as close to the stern as 
possible to minimize ice interference. The 8-airgun array will be towed 
below a depressor bird at a depth of 7-20 m (23-66 ft) depending on ice 
conditions; the preferred depth is 8-10 m (26-33 ft).
    The highest sound level measurable at any location in the water 
from the airgun arrays would be slightly less than the nominal source 
level because the actual source is a distributed source rather than a 
point source. The depth at which the source is towed has a major impact 
on the maximum near-field output, and on the shape of its frequency 
spectrum. In this case, the source is expected to be towed at a 
relatively deep depth of up to 9 m (30 ft).
    The rms (root mean square) received sound levels that are used as 
impact criteria for marine mammals are not directly comparable to the 
peak or peak-to-peak values normally used to characterize source levels 
of airguns. The measurement units used to describe airgun sources, peak 
or peak-to-peak dB, are always higher than the rms dB referred to in 
much of the biological literature. A measured received level of 160 dB 
rms in the far field would typically correspond to a peak measurement 
of about 170 to 172 dB, and to a peak-to-peak measurement of about 176 
to 178 decibels, as measured for the same pulse received at the same 
location (Greene, 1997; McCauley et al., 1998, 2000). The precise 
difference between rms and peak or peak-to-peak values for a given 
pulse depends on the frequency content and duration of the pulse, among 
other factors. However, the rms level is always lower than the peak or 
peak-to-peak level for an airgun-type source. Additional discussion of 
the characteristics of airgun pulses is included in Appendix A of 
UTIG's application.

Safety Radii

    NMFS has determined that for acoustic effects, using established 
acoustic thresholds in combination with corresponding safety radii is 
the most effective way to consistently both apply measures to avoid or 
minimize the impacts of an action and to quantitatively estimate the 
effects of an action. NMFS believes that cetaceans and pinnipeds should 
not be exposed to pulsed underwater noise at received levels exceeding, 
respectively, 180 and 190 dB re 1 microPa (rms) to avoid permanent 
physiological damage (Level A Harassment). NMFS also assumes that 
cetaceans or pinnipeds exposed to levels exceeding 160 dB re 1 microPa 
(rms) experience Level B Harassment. Thresholds are used in two ways: 
(1) To establish a mitigation shut-down or power down zone, i.e., if an 
animal enters an area calculated to be ensonified above the level of an 
established threshold, a sound source is powered down or shut down; and 
(2) to calculate take, in that a model may be used to calculate the 
area around the sound source that will be ensonified to that level or 
above, then, based on the estimated density of animals and the distance 
that the sound source moves, NMFS can estimate the number of marine 
mammals that may be ``taken''.
    In order to implement shut-down zones, or to estimate how many 
animals may potentially be exposed to a particular sound level using 
the acoustic thresholds described above, it is necessary to understand 
how sound will propagate in a particular situation. Models may be used 
to estimate at what distance from the sound source the water will be 
ensonified to a particular level. Safety radii represent the estimated 
distance from the sound source at which the received level of sound 
would correspond to the acoustic thresholds of 190, 180, and 160 dB. 
Many models have been field tested in the water. Field verification has 
shown that some of the predictions are close to being accurate, an some 
are not.
    UTIG proposed to base the safety radii for the Healy cruise on a 
model created by the Lamont-Doherty Earth Observatory and field tested 
in the Gulf of Mexico. UTIG has further proposed to enlarge some of the 
safety radii that relate to shut-down zones to provide further 
protection for marine mammals that may be in the area during seismic 
operations. The model utilized by UTIG to develop their safety radii is 
described below.
Safety Radii Proposed by UTIG
    Received sound fields have been modeled by Lamont-Doherty Earth 
Observatory (L-DEO) for the 8-airgun and 4-GI gun arrays that will be 
used during this survey. Predicted sound fields were modeled using 
sound exposure level (SEL) units (dB re 1 microPa\2\ s), because a 
model based on those units tends to produce more stable output when 
dealing with mixed-gun arrays like the one to be used during this 
survey. The predicted SEL values can be converted to rms received 
pressure levels, in dB re 1 microPa (as used in NMFS' impact criteria 
for pulsed sounds) by adding approximately 15 dB to the SEL value 
(Greene, 1997; McCauley et al., 1998, 2000). The rms pressure is an 
average over the pulse duration. This is the measure commonly used in 
studies of marine mammal reactions to airgun sounds, and in NMFS 
guidelines concerning levels above which ``taking'' might occur. The 
rms level of a seismic pulse is typically about 10 dB less than its 
peak level.
    The empirical data concerning 190, 180, and 160 dB (rms) distances 
in deep and shallow water acquired for various airgun array 
configurations during the acoustic verification study conducted by L-
DEO in the northern Gulf of Mexico. Tolstoy et al., (2004a,b) 
demonstrate that L-DEO's model tends to overestimate the distances 
applied in deep water. The proposed study area will occur mainly in 
water approximately 40-3858 m (131-12,657 ft) deep, with only 
approximately 8 percent of the survey lines in shallow (<100 m (<328 
ft)) water and approximately 23 percent of the trackline in 
intermediate water depths (100-1000 m (328-3,280 ft)). The calibration-
study results showed that radii around the airguns where the received 
level would be 180 dB re 1 microPa (rms), the safety criterion 
applicable to cetaceans (NMFS 2000), vary with water depth. Similar 
depth-related variation is likely in the 190-dB distances applicable to 
pinnipeds.
    UTIG has applied the empirical data collected during the Gulf of 
Mexico verification study to the L-DEO model in the manner described 
below to develop the safety radii listed in Table 1:
     The empirical data indicate that, for deep water (>1000 
m), the L-DEO model tends to overestimate the received sound levels at 
a given distance (Tolstoy et al., 2004a,b). However, to be 
precautionary pending acquisition of additional empirical data, it is 
proposed that safety radii during airgun operations in deep water will 
be the

[[Page 28000]]

values predicted by L-DEO's modeling, after conversion from SEL to rms 
(Table 1).
     Empirical measurements were not conducted for intermediate 
depths (100-1000 m). On the expectation that results would be 
intermediate between those from shallow and deep water, a 1.5 
correction factor is applied to the estimates provided by the model for 
deep water situations (as noted before, NSF is recalculating the 
numbers using a more conservative, or larger, correction factor).
     Empirical measurements were not made for the 4 GI guns 
that will be employed during the proposed survey in shallow water (<100 
m). (The 8-airgun array will not be used in shallow water.) The 
empirical data on operations of two 105 in\3\ GI guns in shallow water 
showed that modeled values underestimated the distance to the actual 
160 dB sound level radii in shallow water by a factor of approximately 
3 (Tolstoy et al., 2004b). Sound level measurements for the 2 GI guns 
were not available for distances <0.5 km (.31 mi)(from the source. The 
radii estimated here for the 4 GI guns operating in shallow water are 
derived from the L-DEO model, with the same adjustments for depth-
related differences between modeled and measured sound levels as were 
used for 2 GI guns in earlier applications. Correction factors for the 
different sound level radii are approximately 12x the model estimate 
for the 190 dB radius in shallow water, approximately 7x for the 180 dB 
radius and approximately 4x for the 170 dB radius [Tolstoy 2004a,b]).
    As mentioned above, UTIG has further proposed expanded safety 
radii, as they apply to the shutdown zones for marine mammals, and 
these are indicated by parentheses in Table 1.
[GRAPHIC] [TIFF OMITTED] TN15MY06.036

Other Acoustic Devices

    Along with the airgun operations, additional acoustical systems 
will be operated during much of or the entire cruise. The ocean floor 
will be mapped with a multibeam sonar, and a sub-bottom profiler will 
be used. These two systems are commonly operated simultaneously with an 
airgun system. An acoustic Doppler current profiler will also be used 
through the course of the project, as well as a pinger.
Multibeam Echosounder (SeaBeam 2112)
    A SeaBeam 2112 multibeam 12 kHz bathymetric sonar system will be 
used on the Healy, with a maximum source output of 237 dB re 1 microPa 
at one meter. The transmit frequency is a very narrow band, less than 
200 Hz, and centered at 12 kHz. Pulse lengths range from less than one 
millisecond to 12 ms. The transmit interval ranges from 1.5 s to 20 s, 
depending on the water depth, and is longer in deeper water. The 
SeaBeam system consists of a set of underhull projectors and 
hydrophones. The transmitted beam is narrow (approximately 2[deg]) in 
the fore-aft direction but broad (approximately 132[deg]) in the cross-
track direction. The system combines this transmitted beam with the 
input from an array of receiving hydrophones oriented perpendicular to 
the array of source transducers, and calculates bathymetric data (sea 
floor depth and some indications about the character of the seafloor) 
with an effective 2[deg] by 2[deg] foot print on the seafloor. The 
SeaBeam 2112

[[Page 28001]]

system on the Healy produces a useable swath width of slightly more 
than 2 times the water depth. This is narrower than normal because of 
the ice-protection features incorporated into the system on the Healy.
Hydrographic Sub-bottom Profiler (Knudsen 320BR)
    The Knudsen 320BR will provide information on sedimentary layering, 
down to between 20 and 70 m, depending on bottom type and slope. It 
will be operated with the multibeam bathymetric sonar system that will 
simultaneously map the bottom topography.
    The Knudsen 320BR sub-bottom profiler is a dual-frequency system 
with operating frequencies of 3.5 and 12 kHz:
    Low frequency - Maximum output power into the transducer array, as 
wired on the Healy (125 ohms), at 3.5 kHz is approximately 6000 watts 
(electrical), which results in a maximum source level of 221 dB re 1 
microPa at 1 m downward. Pulse lengths range from 1.5 to 24 ms with a 
bandwidth of 3 kHz (FM sweep from 3 kHz to 6 kHz). The repetition rate 
is range dependent, but the maximum is a 1-percent duty cycle. Typical 
repetition rate is between 1/2 second (in shallow water) to 8 seconds 
in deep water.
    High frequency - The Knudsen 320BR is capable of operating at 12 
kHz; but the higher frequency is rarely used because it interferes with 
the SeaBeam 2112 multibeam sonar, which also operates at 12 kHz. The 
calculated maximum source level (downward) is 215 dB re 1 microPa at 1 
m (3.28 ft). The pulse duration is typically 1.5 to 5 ms with the same 
limitations and typical characteristics as the low frequency channel.
    A single 12 kHz transducer and one 3.5 kHz, low frequency (sub-
bottom) transducer array, consisting of 16 elements in a 4 by 4 array 
will be used for the Knudsen 320BR. The 12 kHz transducer (TC-12/34) 
emits a conical beam with a width of 30[deg] and the 3.5 kHz transducer 
(TR109) emits a conical beam with a width of 26[deg].
12-kHz Pinger (Benthos 2216)
    A Benthos 12-kHz pinger may be used during coring operations, to 
monitor the depth of the corer relative to the sea floor. The pinger is 
a battery-powered acoustic beacon that is attached to the coring 
mechanism. The pinger produces an omnidirectional 12 kHz signal with a 
source output of approximately 192 dB re 1 microPa m at a one pulse per 
second rate. The pinger produces a single pulse of 0.5, 2 or 10 ms 
duration (hardware selectable within the unit) every second.
Acoustic Doppler Current Profiler (150 kHz)
    The 150 kHz acoustic Doppler current profiler (ADCP ) has a minimum 
ping rate of 0.65 ms. There are four beam sectors, and each beamwidth 
is 3[deg]. The pointing angle for each beam is 30[deg] off from 
vertical with one each to port, starboard, forward and aft. The four 
beams do not overlap. The 150 kHz ADCP's maximum depth range is 300 m.
Acoustic Doppler Current Profiler (RD Instruments Ocean Surveyor 75)
    The Ocean Surveyor 75 is an ADCP operating at a frequency of 75 
kHz, producing a ping every 1.4 s. The system is a four-beam phased 
array with a beam angle of 30[deg]. Each beam has a width of 4[deg], 
and there is no overlap. Maximum output power is 1 kW with a maximum 
depth range of 700 m (2,297 ft).

Description of Habitat and Marine Mammals Affected by the Activity

    A detailed description of the Beaufort and Chukchi sea ecosystems 
and their associated marine mammals can be found in several documents 
(Corps of Engineers, 1999; NMFS, 1999; Minerals Management Service 
(MMS), 2006, 1996 and 1992). MMS' Programmatic Environmental Assessment 
(PEA) - Arctic Ocean Outer Continental Shelf Seismic Surveys - 2006 may 
be viewed at: http://www.mms.gov/alaska/.

Marine Mammals

    A total of 8 cetacean species, 4 species of pinnipeds, and 1 marine 
carnivore are known to or may occur in or near the proposed study area 
(Table 2). Two of these species, the bowhead and fin whale, are listed 
as ``Endangered'' under the ESA, but the fin whale is unlikely to be 
encountered along the planned trackline.
    The marine mammals that occur in the proposed survey area belong to 
three taxonomic groups: odontocetes (toothed cetaceans, such as beluga 
whale and narwhal whale), mysticetes (baleen whales), and carnivora 
(pinnipeds and polar bears). Cetaceans and pinnipeds (except walrus) 
are the subject of the IHA Application to NMFS; in the U.S., the walrus 
and polar bear are managed by the USFWS.
    The marine mammal species most likely to be encountered during the 
seismic survey include one or perhaps two cetacean species (beluga and 
perhaps bowhead whale), three pinniped species (ringed seal, bearded 
seal, and walrus), and the polar bear. However, most of these will 
occur in low numbers and encounters with most species are likely to be 
most common within 100 km (62 mi) of shore where no seismic work is 
planned to take place. The marine mammal most likely to be encountered 
throughout the cruise is the ringed seal. Concentrations of walruses 
might also be encountered in certain areas, depending on the location 
of the edge of the pack ice relative to their favored shallow-water 
foraging habitat. The most widely distributed marine mammals are 
expected to be the beluga, ringed seal, and polar bear.
    Three additional cetacean species, the gray whale, minke whale and 
fin whale, could occur in the project area. It is unlikely that gray 
whales will be encountered near the proposed trackline; if encountered 
at all, gray whales would be found closer to the Alaska coastline where 
no seismic work is planned. Minke and fin whales are extralimital in 
the Chukchi Sea and will not likely be encountered as the proposed 
trackline borders their known range. Two additional pinniped species, 
the harbor and spotted seal, are also unlikely to be seen.
    Table 2 also shows the estimated abundance and densities of the 
marine mammals likely to be encountered during the Healy's Arctic 
cruise. Additional information regarding the distribution of these 
species and how the estimated densities were calculated may be found in 
Conoco's application and NMFS' Updated Species Reports at: (http://www.nmfs.noaa.gov/pr/readingrm/MMSARS/2005alaskasummarySARs.pdf).
BILLING CODE 3510-22-S

[[Page 28002]]

[GRAPHIC] [TIFF OMITTED] TN15MY06.037

BILLING CODE 3510-22-C

[[Page 28003]]

Potential Effects on Marine Mammals

Potential Effects of Airguns

    The effects of sounds from airguns might include one or more of the 
following: tolerance, masking of natural sounds, behavioral 
disturbance, and at least in theory, temporary or permanent hearing 
impairment, or non-auditory physical effects (Richardson et al., 1995). 
Because the airgun sources planned for use during the present project 
involve only 4 or 8 airguns, the effects are anticipated to be less 
than would be the case with a large array of airguns. It is very 
unlikely that there would be any cases of temporary or especially 
permanent hearing impairment, or non-auditory physical effects. Also, 
behavioral disturbance is expected to be limited to relatively short 
distances.
Tolerance
    Numerous studies have shown that pulsed sounds from airguns are 
often readily detectable in the water at distances of many kilometers. 
Numerous studies have shown that marine mammals at distances more than 
a few kilometers from operating seismic vessels often show no apparent 
response (see Appendix A (e) of application). That is often true even 
in cases when the pulsed sounds must be readily audible to the animals 
based on measured received levels and the hearing sensitivity of that 
mammal group. Although various baleen whales, toothed whales, and (less 
frequently) pinnipeds have been shown to react behaviorally to airgun 
pulses under some conditions, at other times mammals of all three types 
have shown no overt reactions. In general, pinnipeds, small 
odontocetes, and sea otters seem to be more tolerant of exposure to 
airgun pulses than are baleen whales.
Masking
    Masking effects of pulsed sounds (even from large arrays of 
airguns) on marine mammal calls and other natural sounds are expected 
to be limited, although there are very few specific data of relevance. 
Some whales are known to continue calling in the presence of seismic 
pulses. Their calls can be heard between the seismic pulses (e.g., 
Richardson et al., 1986; McDonald et al., 1995; Greene et al., 1999; 
Nieukirk et al., 2004). Although there has been one report that sperm 
whales cease calling when exposed to pulses from a very distant seismic 
ship (Bowles et al., 1994), a more recent study reports that sperm 
whales off northern Norway continued calling in the presence of seismic 
pulses (Madsen et al., 2002). That has also been shown during recent 
work in the Gulf of Mexico (Tyack et al., 2003). Masking effects of 
seismic pulses are expected to be negligible in the case of the smaller 
odontocete cetaceans, given the intermittent nature of seismic pulses. 
Also, the sounds important to small odontocetes are predominantly at 
much higher frequencies than are airgun sounds. For more information on 
masking effects, see Appendix A (d) of the application.
Disturbance Reactions
    Disturbance includes a variety of effects, including subtle changes 
in behavior, more conspicuous changes in activities, and displacement. 
Reactions to sound, if any, depend on species, state of maturity, 
experience, current activity, reproductive state, time of day, and many 
other factors. If a marine mammal does react briefly to an underwater 
sound by changing its behavior or moving a small distance, the impacts 
of the change are unlikely to be significant to the individual, let 
alone the stock or the species as a whole. Alternatively, if a sound 
source displaces marine mammals from an important feeding or breeding 
area for a prolonged period, impacts on the animals are most likely 
significant. There are some uncertainties in predicting the quantity 
and types of impacts of noise on marine mammals. When attempting to 
quantify potential take for an authorization, NMFS estimates how many 
mammals were likely within a certain distance of sound level that 
equates to the received sound level.
    The sound criteria used to estimate how many marine mammals might 
be disturbed to some biologically-important degree by a seismic program 
are based on behavioral observations during studies of several species. 
However, information is lacking for many species. Detailed studies have 
been done on humpback, gray, and bowhead whales, and on ringed seals. 
Less detailed data are available for some other species of baleen 
whales, sperm whales, small toothed whales, and sea otters.
    Baleen Whales: Baleen whales generally tend to avoid operating 
airguns, but avoidance radii are quite variable. Whales are often 
reported to show no overt reactions to pulses from large arrays of 
airguns at distances beyond a few kilometers, even though the airgun 
pulses remain well above ambient noise levels out to much longer 
distances. However, as reviewed in Appendix A (e) of the application, 
baleen whales exposed to strong noise pulses from airguns often react 
by deviating from their normal migration route and/or interrupting 
their feeding and moving away. In the case of the migrating gray and 
bowhead whales, the observed changes in behavior appeared to be of 
little or no biological consequence to the animals. They simply avoided 
the sound source by displacing their migration route to varying 
degrees, but within the natural boundaries of the migration corridors.
    Studies of gray, bowhead, and humpback whales have determined that 
received levels of pulses in the 160-170 dB re 1 microPa rms range seem 
to cause obvious avoidance behavior in a substantial fraction of the 
animals exposed. In many areas, seismic pulses from large arrays of 
airguns diminish to those levels at distances ranging from 4.5 to 14.5 
km (2.8-9 mi) from the source. A substantial proportion of the baleen 
whales within those distances may show avoidance or other strong 
disturbance reactions to the airgun array. Subtle behavioral changes 
sometimes become evident at somewhat lower received levels, and recent 
studies reviewed in Appendix A (e) of the application have shown that 
some species of baleen whales, notably bowhead and humpback whales, at 
times show strong avoidance at received levels lower than 160-170 dB re 
1 microPa rms. Bowhead whales migrating west across the Alaskan 
Beaufort Sea in autumn, in particular, are unusually responsive, with 
substantial avoidance occurring out to distances of 20-30 km (12.4-18.6 
mi) from a medium-sized airgun source (Miller et al., 1999; Richardson 
et al., 1999). More recent research on bowhead whales (Miller et al., 
2005), however, suggests that during the summer feeding season (during 
which the proposed project will take place) bowheads are not nearly as 
sensitive to seismic sources and can be expected to react to the more 
typical 160-170 dB re 1 Pa rms range.
    Malme et al. (1986, 1988) studied the responses of feeding eastern 
gray whales to pulses from a single 100 in\3\ airgun off St. Lawrence 
Island in the northern Bering Sea. They estimated, based on small 
sample sizes, that 50 percent of feeding gray whales ceased feeding at 
an average received pressure level of 173 dB re 1 microPa on an 
(approximate) rms basis, and that 10 percent of feeding whales 
interrupted feeding at received levels of 163 dB. Those findings were 
generally consistent with the results of experiments conducted on 
larger numbers of gray whales that were migrating along the California 
coast.
    Data on short-term reactions (or lack of reactions) of cetaceans to 
impulsive

[[Page 28004]]

noises do not necessarily provide information about long-term effects. 
It is not known whether impulsive noises affect reproductive rate or 
distribution and habitat use in subsequent days or years. However, gray 
whales 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). Bowhead 
whales 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). Populations of both gray whales and 
bowhead whales grew substantially during this time. In any event, the 
brief exposures to sound pulses from the proposed airgun source are 
highly unlikely to result in prolonged effects.
    Toothed Whales: Little systematic information is available about 
reactions of toothed whales to noise pulses. Few studies similar to the 
more extensive baleen whale/seismic pulse work summarized above and in 
Appendix A of the application have been reported for toothed whales. 
However, systematic work on sperm whales is underway (Tyack et al., 
2003), and there is 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).
    Seismic operators sometimes see dolphins and other small toothed 
whales near operating airgun arrays, but in general there seems to be a 
tendency for most delphinids to show some limited avoidance of seismic 
vessels operating large airgun systems. However, some dolphins seem to 
be attracted to the seismic vessel and floats, and some ride the bow 
wave of the seismic vessel even when large arrays of airguns are 
firing. Nonetheless, there have been indications that small toothed 
whales sometimes move away, or maintain a somewhat greater distance 
from the vessel, when a large array of airguns is operating than when 
it is silent (e.g., Goold, 1996a,b,c; Calambokidis and Osmek, 1998; 
Stone, 2003). Aerial surveys during seismic operations in the 
southeastern Beaufort Sea recorded much lower sighting rates of beluga 
whales within 10-20 km (6.2-12.4 mi) of an active seismic vessel. These 
results were consistent with the low number of beluga sightings 
reported by observers aboard the seismic vessel, suggesting that some 
belugas might be avoiding the seismic operations at distances of 10-20 
km (6.2-12.4 mi) (Miller et al., 2005).
    Similarly, captive bottlenose dolphins and (of some relevance in 
this project) beluga whales exhibit changes in behavior when exposed to 
strong pulsed sounds similar in duration to those typically used in 
seismic surveys (Finneran et al., 2000, 2002). However, the animals 
tolerated high received levels of sound (pk-pk level >200 dB re 1 
microPa) before exhibiting aversive behaviors. With the presently-
planned source, such levels would be found within approximately 400 m 
(1,312 ft) of the 4 GI guns operating in shallow water.
    Odontocete reactions to large arrays of airguns are variable and, 
at least for small odontocetes, seem to be confined to a smaller radius 
than has been observed for mysticetes. UTIG proposed using a 170-dB 
acoustic threshold for behavioral disturbance of delphinids and 
pinnipeds in lieu of the 160-dB NMFS currently uses as the standard 
threshold. However, NMFS does not believe there is enough data to 
support changing the threshold at this time and will utilize the 160 dB 
safety radii. NMFS is currently developing new taxa-specific acoustic 
criteria and they are scheduled to be made available to the public 
within the next two years.
    Pinnipeds: Pinnipeds are not likely to show a strong avoidance 
reaction to the medium-sized airgun sources that will be used. Visual 
monitoring from seismic vessels has shown only slight (if any) 
avoidance of airguns by pinnipeds, and only slight (if any) changes in 
behavior-see Appendix A (e) of the application. Those studies show that 
pinnipeds frequently do not avoid the area within a few hundred meters 
of operating airgun arrays (e.g., Miller et al., 2005; Harris et al., 
2001). However, initial telemetry work suggests that avoidance and 
other behavioral reactions to small airgun sources may at times be 
stronger than evident to date from visual studies of pinniped reactions 
to airguns (Thompson et al., 1998). Even if reactions of the species 
occurring in the present study area are as strong as those evident in 
the telemetry study, reactions are expected to be confined to 
relatively small distances and durations, with no long-term effects on 
pinniped individuals or populations.
Hearing Impairment and Other Physical Effects
    Temporary or permanent hearing impairment is a possibility when 
marine mammals are exposed to very strong sounds, but there has been no 
specific documentation of this for marine mammals exposed to sequences 
of airgun pulses. Current NMFS practice regarding exposure of marine 
mammals to high-level sounds is to establish mitgation that will avoid 
cetaceans and pinnipeds exposure to impulsive sounds 180 and 190 dB re 
1 microPa (rms), respectively (NMFS, 2000). Those criteria have been 
used in defining the safety (shut down) radii planned for the proposed 
seismic survey. As summarized here,
     The 180 dB criterion for cetaceans may be lower than 
necessary to avoid temporary threshold shift (TTS), let alone permanent 
auditory injury, at least for belugas and delphinids.
     The minimum sound level necessary to cause permanent 
hearing impairment is higher, by a variable and generally unknown 
amount, than the level that induces barely-detectable TTS.
     The level associated with the onset of TTS is often 
considered to be a level below which there is no danger of permanent 
damage.
    NMFS is presently developing new noise exposure criteria for marine 
mammals that account for the now-available scientific data on TTS and 
other relevant factors in marine and terrestrial mammals.
    Several aspects of the proposed monitoring and mitigation measures 
for this project are designed to detect marine mammals occurring near 
the airguns (and multi-beam bathymetric sonar), and to avoid exposing 
them to sound pulses that might, at least in theory, cause hearing 
impairment (see Mitigation). In addition, many cetaceans are likely to 
show some avoidance of the area with high received levels of airgun 
sound (see above). In those cases, the avoidance responses of the 
animals themselves will reduce or (most likely) avoid any possibility 
of hearing impairment.
    Non-auditory physical effects might also 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 stress, 
neurological effects, bubble formation, and other types of organ or 
tissue damage. It is possible that some marine mammal species (i.e., 
beaked whales) may be especially susceptible to injury and/or stranding 
when exposed to strong pulsed sounds. However, as discussed below, 
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 present study area. It is unlikely 
that any effects of these types would occur during the present project 
given the brief duration of exposure of any given

[[Page 28005]]

mammal, and the planned monitoring and mitigation measures (see below). 
The following subsections discuss in somewhat more detail the 
possibilities of TTS, permanent threshold shift (PTS), and non-auditory 
physical effects.
    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. TTS can last from minutes or hours to (in cases of strong 
TTS) days. For sound exposures at or somewhat above the TTS threshold, 
hearing sensitivity recovers rapidly after exposure to the noise ends. 
Few data on sound levels and durations necessary to elicit mild TTS 
have been obtained for marine mammals, and none of the published data 
concern TTS elicited by exposure to multiple pulses of sound.
    For toothed whales exposed to single short pulses, the TTS 
threshold appears to be, to a first approximation, a function of the 
energy content of the pulse (Finneran et al., 2005, 2002). Given the 
available data, the received level of a single seismic pulse might need 
to be approximately 210 dB re 1 Pa rms (approximately 221-226 dB pk-pk) 
in order to produce brief, mild TTS. Exposure to several seismic pulses 
at received levels near 200-205 dB (rms) might result in slight TTS in 
a small odontocete, assuming the TTS threshold is (to a first 
approximation) a function of the total received pulse energy. Seismic 
pulses with received levels of 200-205 dB or more are usually 
restricted to a radius of no more than 200 m around a seismic vessel 
operating a large array of airguns.
    For baleen whales, there are no data, direct or indirect, on levels 
or properties of sound that are required to induce TTS. However, no 
cases of TTS are expected given the moderate size of the source, and 
the strong likelihood that baleen whales 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; Ketten 
et al., 2001; cf. Au et al., 2000).
    A marine mammal within a radius of 100 m (328 ft) around a typical 
large array of operating airguns might be exposed to a few seismic 
pulses with levels of 205 dB, and possibly more pulses if the mammal 
moved with the seismic vessel. The sound level radius would be similar 
(100 m) around the proposed 8-airgun array while surveying in 
intermediate depths (100-1000 m). This would occur for <23 percent 
(approximately 838 km (520 mi)) of the survey when the survey will be 
conducted in intermediate depths. Also, the PIs propose using the 4 GI 
guns for some of the intermediate-depth survey, which would greatly 
reduce the 205 dB sound radius. (As noted above, most cetacean species 
tend to avoid operating airguns, although not all individuals do so.) 
However, several of the considerations that are relevant in assessing 
the impact of typical seismic surveys with arrays of airguns are not 
directly applicable here:
     ``Ramping up'' (soft start) is standard operational 
protocol during startup of large airgun arrays. Ramping up involves 
starting the airguns in sequence, usually commencing with a single 
airgun and gradually adding additional airguns. This practice will be 
employed when either airgun array is operated.
     It is unlikely that 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. In this project, most of the seismic survey will be 
in deep water where the radius of influence and duration of exposure to 
strong pulses is smaller.
     With a large array of airguns, TTS would be most likely in 
any odontocetes that bow-ride or otherwise linger near the airguns. In 
the present project, the anticipated 180-dB distances in deep and 
intermediate-depth water are 716 m (2,349 ft) and 1074 m (3,524 ft), 
respectively, for the 8-airgun gun system (Table 1) and 246 m (840 ft) 
and 369 m (1,207 ft), respectively for the 4-GI gun system. The 
waterline at the bow of the Healy will be approximately 123 m (404 ft) 
ahead of the airgun. However, no species that occur within the project 
area are expected to bow-ride.
    The predicted 180 and 190 dB distances for the airguns operated by 
UTIG vary with water depth. They are estimated to be 716 m (2,349 ft) 
and 230 m (754 ft), respectively, in deep water for the 8-airgun 
system, and 246 m (807 ft) and 75 m (246 ft), respectively, in deep 
water for the 4-GI gun system. In intermediate depths, these distances 
are predicted to increase to 1074 m (3,523 ft) and 345 m (1,131 ft), 
respectively for the 8-airgun system, and 369 m (1,210 ft) and 113 m 
(371 ft), respectively for the 4-GI gun system. The predicted 180 and 
190 dB distances for the 4-GI gun system in shallow water are 1822 m 
(5,978 ft) and 938 m (3,077 ft), respectively (Table 1). The 8-airgun 
array will not be operated in shallow water. Shallow water (<100 m (328 
ft)) will occur along only 300 km (186 mi) (approximately 8 percent) of 
the planned trackline. Furthermore, those sound levels are not 
considered to be the levels above which TTS might occur. Rather, they 
are the received levels above which, in the view of a panel of 
bioacoustics specialists convened by NMFS before TTS measurements for 
marine mammals started to become available, one could not be certain 
that there would be no injurious effects, auditory or otherwise, to 
marine mammals. As summarized above, data that are now available imply 
that TTS is unlikely to occur unless odontocetes are exposed to airgun 
pulses much stronger than 180 dB re 1 Pa rms and since no bow-riding 
species occur in the study area, it is unlikely such exposures will 
occur.
    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.
    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 possibility that mammals close to an airgun 
array might incur TTS, there has been further speculation about the 
possibility that some individuals occurring very close to airguns might 
incur PTS. Single or occasional occurrences of mild TTS are not 
indicative of permanent auditory damage in terrestrial mammals. 
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. PTS might occur at a received sound level at 
least several decibels above that inducing mild TTS if the animal were 
exposed to the strong sound pulses with very rapid rise time-see 
Appendix A (f) of the application.
    It is highly unlikely that marine mammals could receive sounds 
strong enough (and over a sufficient duration) to cause permanent 
hearing impairment during a project employing the medium-sized airgun 
sources planned here. In the proposed project, marine mammals are 
unlikely to be exposed to received levels of seismic pulses strong 
enough to cause TTS, as they would probably need to be within 100-200 m 
(328-656

[[Page 28006]]

ft) of the airguns for that to occur. Given the higher level of sound 
necessary to cause PTS, it is even less likely that PTS could occur. In 
fact, even the levels immediately adjacent to the airgun may not be 
sufficient to induce PTS, especially because a mammal would not be 
exposed to more than one strong pulse unless it swam immediately 
alongside the airgun for a period longer than the inter-pulse interval. 
Baleen whales generally avoid the immediate area around operating 
seismic vessels. The planned monitoring and mitigation measures, 
including visual monitoring, power downs, and shut downs of the airguns 
when mammals are seen within the ``safety radii'', will minimize the 
already-minimal probability of exposure of marine mammals to sounds 
strong enough to induce PTS.
    Non-auditory Physiological Effects: Non-auditory physiological 
effects or injuries that theoretically might occur in marine mammals 
exposed to strong underwater sound include stress, neurological 
effects, bubble formation, and other types of organ or tissue damage. 
However, studies examining such effects are very limited. If any such 
effects do occur, they probably would be limited to unusual situations 
when animals might be exposed at close range for unusually long 
periods. It is doubtful that any single marine mammal would be exposed 
to strong seismic sounds for sufficiently long that significant 
physiological stress would develop. That is especially so in the case 
of the proposed project where the airgun configuration is moderately 
sized, the ship is moving at 3-4 knots (5.5-7.4 km/hr), and for the 
most part, the tracklines will not ``double back'' through the same 
area.
    Until recently, it was assumed that diving marine mammals are not 
subject to the bends or air embolism. This possibility was first 
explored at a workshop (Gentry [ed.], 2002) held to discuss whether the 
stranding of beaked whales in the Bahamas in 2000 (Balcomb and 
Claridge, 2001; NOAA and USN, 2001) might have been related to bubble 
formation in tissues caused by exposure to noise from naval sonar. 
However, the opinions were inconclusive. Jepson et al. (2003) first 
suggested a possible link between mid-frequency sonar activity and 
acute and chronic tissue damage that results from the formation in vivo 
of gas bubbles, based on the beaked whale stranding in the Canary 
Islands in 2002 during naval exercises. Fernandez et al. (2005a) showed 
those beaked whales did indeed have gas bubble-associated lesions as 
well as fat embolisms. Fernandez et al. (2005b) also found evidence of 
fat embolism in three beaked whales that stranded 100 km north of the 
Canaries in 2004 during naval exercises. Examinations of several other 
stranded species have also revealed evidence of gas and fat embolisms 
(e.g., Arbelo et al., 2005; Jepson et al., 2005a; Mendez et al., 2005). 
Most of the afflicted species were deep divers. There is speculation 
that gas and fat embolisms may occur if cetaceans ascend unusually 
quickly when exposed to aversive sounds, or if sound in the environment 
causes the destabilization of existing bubble nuclei (Potter, 2004; 
Arbelo et al., 2005; Fernandez et al., 2005a; Jepson et al., 2005b). 
Even if gas and fat embolisms can occur during exposure to mid-
frequency sonar, there is no evidence that that type of effect occurs 
in response to airgun sounds. Also, most evidence for such effects have 
been in beaked whales, which do not occur in the proposed study area.
    In general, little is known about the potential for seismic survey 
sounds to cause auditory impairment or other physical effects in marine 
mammals. Available data suggest that such effects, if they occur at 
all, would be limited to short distances and probably to projects 
involving large arrays of airguns. However, the available data do not 
allow for meaningful quantitative predictions of the numbers (if any) 
of marine mammals that might be affected in those ways. 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 auditory impairment or 
other physical effects. Also, the planned monitoring and mitigation 
measures include shut downs of the airguns, which will reduce any such 
effects that might otherwise occur.
Strandings and Mortality
    Marine mammals close to underwater detonations of high explosive 
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 have slower rise times, and there 
is no proof that they can cause serious injury, death, or stranding 
even in the case of large airgun arrays. However, the association of 
mass strandings of beaked whales with naval exercises and, in one case, 
an L-DEO seismic survey, has raised the possibility that beaked whales 
exposed to strong pulsed sounds may be especially susceptible to injury 
and/or behavioral reactions that can lead to stranding. Appendix A (g) 
of the application provides additional details.
    Seismic pulses and mid-frequency sonar pulses are quite different. 
Sounds produced by airgun arrays are broadband with most of the energy 
below 1 kHz. Typical military mid-frequency sonars operate at 
frequencies of 2-10 kHz, generally with a relatively narrow bandwidth 
at any one time. Thus, it is not appropriate to assume that there is a 
direct connection between the effects of military sonar and seismic 
surveys on marine mammals. However, evidence that sonar pulses can, in 
special circumstances, lead to physical damage and mortality (NOAA and 
USN, 2001; Jepson et al., 2003; Fernandez et al., 2005a), even if only 
indirectly, suggests that caution is warranted when dealing with 
exposure of marine mammals to any high-intensity pulsed sound.
    In May 1996, 12 Cuvier's beaked whales stranded along the coasts of 
Kyparissiakos Gulf in the Mediterranean Sea. That stranding was 
subsequently linked to the use of low- and medium-frequency active 
sonar by a North Atlantic Treaty Organization (NATO) research vessel in 
the region (Frantzis, 1998). In March 2000, a population of Cuvier's 
beaked whales being studied in the Bahamas disappeared after a U.S. 
Navy task force using mid-frequency tactical sonars passed through the 
area; some beaked whales stranded (Balcomb and Claridge, 2001; NOAA and 
USN, 2001).
    In September 2002, a total of 14 beaked whales of various species 
stranded coincident with naval exercises in the Canary Islands (Martel, 
n.d.; Jepson et al., 2003; Fernandez et al., 2003). Also in September 
2002, there was a stranding of two Cuvier's beaked whales in the Gulf 
of California, Mexico, when the L-DEO vessel Maurice Ewing was 
operating a 20 airgun, 8490 in3 array in the general area. The link 
between the stranding and the seismic surveys was inconclusive and not 
based on any physical evidence (Hogarth, 2002; Yoder, 2002). 
Nonetheless, that plus the incidents involving beaked whale strandings 
near naval exercises suggests a need for caution in conducting seismic 
surveys in areas occupied by beaked whales. However, no beaked whales 
are found within this project area and the planned monitoring and 
mitigation measures are expected to minimize any possibility for 
mortality of other species.

Potential Effects of Other Acoustic Devices

Bathymetric Sonar Signals
    A SeaBeam 2112 multibeam 12 kHz bathymetric sonar system will be

[[Page 28007]]

operated from the source vessel essentially continuously during the 
planned study. Sounds from the multibeam are very short pulses, 
depending on water depth. Most of the energy in the sound pulses 
emitted by the multibeam is at moderately high frequencies, centered at 
12 kHz. The beam is narrow (approximately 2[deg]) in fore-aft extent 
and wide (approximately 130[deg]) in the cross-track extent. Any given 
mammal at depth near the trackline would be in the main beam for only a 
fraction of a second. Therefore, marine mammals that encounter the 
SeaBeam 2112 at close range are unlikely to be subjected to repeated 
pulses because of the narrow fore-aft width of the beam, and will 
receive only limited amounts of pulse energy because of the short 
pulses. Similarly, Kremser et al. (2005) noted that the probability of 
a cetacean swimming through the area of exposure when a multibeam sonar 
emits a pulse is small. The animal would have to pass the transducer at 
close range and be swimming at speeds similar to the vessel in order to 
be subjected to sound levels that could cause TTS.
    Navy sonars that have been linked to avoidance reactions and 
stranding of cetaceans (1) generally are more powerful than the SeaBeam 
2112 sonar, (2) have a longer pulse duration, (3) are directed close to 
horizontally vs. downward for the SeaBeam 2112, and (4) have a wider 
beam width. The area of possible influence of the bathymetric sonar is 
much smaller, a narrow band oriented in the cross-track direction below 
the source vessel. Marine mammals that encounter the bathymetric sonar 
at close range are unlikely to be subjected to repeated pulses because 
of the narrow fore-aft width of the beam, and will receive only small 
amounts of pulse energy because of the short pulses. In assessing the 
possible impacts of a similar multibeam system (the 15.5 kHz Atlas 
Hydrosweep multibeam bathymetric sonar), Boebel et al. (2004) noted 
that the critical sound pressure level at which TTS may occur is 203.2 
dB re 1 microPa (rms). The critical region included an area of 43 m 
(141 ft) in depth, 46 m (151 ft) wide athwartship, and 1 m (3.3 ft) 
fore-and-aft (Boebel et al., 2004). In the more distant parts of that 
(small) critical region, only slight TTS could potentially be incurred. 
This area is included within the 160 dB isopleth for airguns, in which 
Level B Harassment is already assumed to occur when th airguns are 
operating.
    Behavioral reactions of free-ranging marine mammals to military and 
other sonars appear to vary by species and circumstance. Observed 
reactions have included silencing and dispersal by sperm whales 
(Watkins et al., 1985), increased vocalizations and no dispersal by 
pilot whales (Rendell and Gordon, 1999), and the previously-mentioned 
beachings by beaked whales. Also, Navy personnel have described 
observations of dolphins bow-riding adjacent to bow-mounted mid-
frequency sonars during sonar transmissions. During exposure to a 21-25 
kHz whale-finding sonar with a source level of 215 dB re 1 microPa m, 
gray whales showed slight avoidance (approximately 200 m (656 ft)) 
behavior (Frankel, 2005).
    However, all of those observations are of limited relevance to the 
present situation. Pulse durations from the Navy sonars were much 
longer than those of the bathymetric sonars to be used during the 
proposed study, and a given mammal would have received many pulses from 
the naval sonars. During UTIG's operations, the individual pulses will 
be very short, and a given mammal would rarely receive more than one of 
the downward-directed pulses as the vessel passes by.
    Captive bottlenose dolphins and a white whale exhibited changes in 
behavior when exposed to 1 second of pulsed sounds at frequencies 
similar to those that will be emitted by the bathymetric sonar to be 
used by UTIG, and to shorter broadband pulsed signals. Behavioral 
changes typically involved what appeared to be deliberate attempts to 
avoid the sound exposure (Schlundt et al., 2000; Finneran et al., 2002; 
Finneran and Schlundt, 2004). The relevance of those data to free-
ranging odontocetes is uncertain, and in any case, the test sounds were 
quite different in either duration or bandwidth as compared with those 
from a bathymetric sonar.
    We are not aware of any data on the reactions of pinnipeds to sonar 
sounds at frequencies similar to those of the multibeam sonar (12 kHz). 
Based on observed pinniped responses to other types of pulsed sounds, 
and the likely brevity of exposure to the bathymetric sonar sounds, 
pinniped reactions to the sonar sounds are expected to be limited to 
startle or otherwise brief responses of no lasting consequence to the 
animals.
Sub-bottom Profiler Signals
    A Knudsen 320BR sub-bottom profiler will be operated from the 
source vessel at nearly all times during the planned study. The Knudsen 
320BR produces sound pulses with lengths of up to 24 ms every 0.5 to 
approximately 8 s, depending on water depth. The energy in the sound 
pulses emitted by this sub-bottom profiler is at mid- to moderately 
high frequency, depending on whether the 3.5 or 12 kHz transducer is 
operating. The conical beamwidth is either 26[deg], for the 3.5 kHz 
transducer, or 30[deg], for the 12 kHz transducer, and is directed 
downward.
    Source levels for the Knudsen 320 operating at 3.5 and 12 kHz have 
been measured as a maximum of 221 and 215 dB re 1 microPa m, 
respectively. Received levels would diminish rapidly with increasing 
depth. Assuming circular spreading, received level directly below the 
transducer(s) would diminish to 180 dB re 1 microPa at distances of 
about 112 m (367 ft) when operating at 3.5 kHz, and 56 m when operating 
at 12 kHz. The 180 dB distances in the horizontal direction (outside 
the downward-directed beam) would be substantially less. Kremser et al. 
(2005) noted that the probability of a cetacean swimming through the 
area of exposure when a bottom profiler emits a pulse is small, and if 
the animal was in the area, it would have to pass the transducer at 
close range and in order to be subjected to sound levels that could 
potentially cause TTS.
    The sub-bottom profiler is usually operated simultaneously with 
other higher-power acoustic sources. Many marine mammals will move away 
in response to the approaching higher-power sources or the vessel 
itself before the mammals would be close enough for there to be any 
possibility of effects from the sub-bottom profiler (see Appendix A in 
the application). In the case of mammals that do not avoid the 
approaching vessel and its various sound sources, mitigation measures 
that would be applied to minimize effects of the higher-power sources 
would further reduce or eliminate any minor effects of the sub-bottom 
profiler.
Pinger Signals
    A pinger will be operated during all coring, to monitor the depth 
of the core relative to the sea floor. Sounds from the pinger are very 
short pulses, occurring for 0.5, 2 or 10 ms once every second, with 
source level approximately 192 dB re 1 microPa m at a one pulse per 
second rate. Most of the energy in the sound pulses emitted by this 
pinger is at mid frequencies, centered at 12 kHz. The signal is 
omnidirectional. The pinger produces sounds that are within the range 
of frequencies used by small odontocetes and pinnipeds that occur or 
may occur in the area of the planned survey.
    Marine mammal behavioral reactions to other pulsed sound sources 
are discussed above, and responses to the pinger are likely to be 
similar to those for other pulsed sources if received at the same 
levels. However, the pulsed

[[Page 28008]]

signals from the pinger are much weaker than those from the bathymetric 
sonars and from the airgun. Therefore, neither behavioral responses nor 
TTS would potentially occur unless marine mammals were to get very 
close to the source, which is unlikely due to the fact that animals 
will probably move away from the ship in response to the louder sounds 
from the other sources operating and the vessel itself, and the fact 
that the proposed mitigation and monitoring measures will be 
implemented during the operation of the airguns.

Effects of Helicopter Activities

    Collection of seismic refraction data requires the deployment of 
hydrophones at great distances from the source vessel. In order to 
accomplish this in the ice-covered waters of the Arctic Ocean, the 
science party plans to deploy SISs along seismic lines in front of the 
Healy and then retrieve them off the ice once the vessel has passed. 
Vessel-based helicopters will be used to shuttle SISs along seismic 
track lines. Deployment and recovery of SISs every 10-15 km (6.2-9.3 
mi) along the track line and as far as 120 km (75 mi) ahead or behind 
the vessel will require as many as 24 on-ice landings per 24-hr period 
during seismic shooting.
    Levels and duration of sounds received underwater from a passing 
helicopter are a function of the type of helicopter used, orientation 
of the helicopter, the depth of the marine mammal, and water depth. A 
civilian helicopter service will be providing air support for this 
project and we do not yet know what type of helicopter will be used. 
Helicopter sounds are detectable underwater at greater distances when 
the receiver is at shallow depths. Generally, sound levels received 
underwater decrease as the altitude of the helicopter increases 
(Richardson et al., 1995). Helicopter sounds are audible for much 
greater distances in air than in water.
Cetaceans
    The nature of sounds produced by helicopter activities above the 
surface of the water does not pose a direct threat to the hearing of 
marine mammals that are in the water; however minor and short-term 
behavioral responses of cetaceans to helicopters have been documented 
in several locations, including the Beaufort Sea (Richardson et al., 
1985a,b; Patenaude et al., 2002). Cetacean reactions to helicopters 
depend on several variables including the animal's behavioral state, 
activity, group size, habitat, and the flight patterns used, among 
other variables (Richardson et al., 1995). During spring migration in 
the Beaufort Sea, beluga whales reacted to helicopter noise more 
frequently and at greater distances than did bowhead whales (38 percent 
vs.14 percent of observations, respectively). Most reaction occurred 
when the helicopter passed within 250 m (820 ft) lateral distance at 
altitudes <150 m (492 ft). Neither species exhibited noticeable 
reactions to single passes at altitudes >150 m (492 ft). Belugas within 
250 m (820 ft) of stationary helicopters on the ice with the engine 
running showed the most overt reactions (Patenaude et al., 2002). 
Whales were observed to make only minor changes in direction in 
response to sounds produced by helicopters, so all reactions to 
helicopters were considered brief and minor. Cetacean reactions to 
helicopter disturbance are difficult to predict and may range from no 
reaction at all to minor changes in course or (infrequently) leaving 
the immediate area of the activity.
Pinnipeds
    Few systematic studies of pinniped reactions to aircraft 
overflights have been completed. Documented reactions range from simply 
becoming alert and raising the head to escape behavior such as hauled 
out animals rushing to the water. Ringed seals hauled out on the 
surface of the ice have shown behavioral responses to aircraft 
overflights with escape responses most probable at lateral distances 
<200 m (656 ft) and overhead distances <150 m (492 ft) (Born et al., 
1999). Although specific details of altitude and horizontal distances 
are lacking from many largely anecdotal reports, escape reactions to a 
low flying helicopter (<150 m (492 ft) altitude) can be expected from 
all four species of pinnipeds potentially encountered during the 
proposed operations. These responses would likely be relatively minor 
and brief in nature. Whether any response would occur when a helicopter 
is at the higher suggested operational altitudes (below) is difficult 
to predict and probably a function of several other variables including 
wind chill, relative wind chill, and time of day (Born et al., 1999).
    In order to limit behavioral reactions of marine mammals during 
deployment of SISs, helicopters will maintain a minimum altitude of 
1000 ft (304 m) above the sea ice except when taking off or landing. 
Sea-ice landings within 1000 ft (304 m) of any observed marine mammal 
will not occur, and the helicopter flight path will remain along the 
seismic track line. Three or four SIS units will be deployed/retrieved 
before the helicopter returns to the vessel. This should minimize the 
number of disturbances caused by repeated over-flights.

Estimated Take by Incidental Harassment for Chukchi Sea Seismic Survey

    All anticipated takes would be ``takes by harassment'', as 
described previously, involving temporary changes in behavior. In the 
sections below, we describe methods to estimate ``take by harassment'' 
and present estimates of the numbers of marine mammals that might be 
affected during the proposed seismic study in the Arctic Ocean. The 
estimates are based on data obtained during marine mammal surveys in 
and near the Arctic Ocean by Stirling et al. (1982), Kingsley (1986), 
Koski and Davis (1994), Moore et al. (2000a), and Moulton and Williams 
(2003), and on estimates of the sizes of the areas where effects could 
potentially occur. In some cases, these estimates were made from data 
collected from regions and habitats that differed from the proposed 
project area. Adjustments to reported population or density estimates 
were made on a case by case basis to take into account differences 
between the source data and the general information on the distribution 
and abundance of the species in the project area. This section provides 
estimates of the number of potential ``exposures'' to sound levels 
equal or greater than 160 dB.
    Although several systematic surveys of marine mammals have been 
conducted in the southern Beaufort Sea, few data (systematic or 
otherwise) are available on the distribution and numbers of marine 
mammals in the northern Chukchi and Beaufort Seas or offshore water of 
the Arctic Ocean. The main sources of distributional and numerical data 
used in deriving the estimates are described in detail in UTIG's 
application. There is some uncertainty about the representativeness of 
those data and the assumptions used below to estimate the potential 
``take by harassment''. However, the approach used here seems to be the 
best available at this time.
    The following estimates are based on a consideration of the number 
of marine mammals that might be disturbed appreciably by approximately 
3624 line kilometers (2,251 mi) of seismic surveys across the Arctic 
Ocean. An assumed total of 4530 km (2,815 mi) of trackline includes a 
25-percent allowance over and above the planned approximately 3624 km 
(2,251 mi) to allow for turns, lines that might have to be repeated 
because of poor data quality, or for minor changes to the survey 
design.

[[Page 28009]]

    As noted above, there is some uncertainty about the 
representativeness of the data and assumptions used in the 
calculations. To provide some allowance for the uncertainties, 
``maximum estimates'' as well as ``best estimates'' of the numbers 
potentially affected have been derived (Table 1). For a few marine 
mammal species, several density estimates were available, and in those 
cases, the mean and maximum estimates were calculated from the survey 
data. When the seismic survey area is on the edge of the range of a 
species, we used the available mammal survey data as the maximum 
estimate and assumed that the average density along the seismic 
trackline will be approximately 0.10 times the density from the 
available survey data. The assumed densities are believed to be similar 
to, or in most cases higher than, the densities that will actually be 
encountered during the survey.
    The anticipated radii of influence of the bathymetric sonar, sub-
bottom profiler, and pinger are less than those for the airgun 
configurations. NMFS assumes that, during simultaneous operations of 
all the airgun array, sonar, and profiler, any marine mammals close 
enough to be affected by the sonars would already be affected by the 
airguns. The pinger will operate only during coring while the airguns 
are not in operation. However, whether or not the airguns are operating 
simultaneously with the sonar, profiler or pinger, marine mammals are 
expected to exhibit no more than short-term and inconsequential 
responses to the sonar, profiler or pinger given their characteristics 
(e.g., narrow downward-directed beam) and other considerations 
described previously. Such reactions are not considered to constitute 
``taking'' and, therefore, no additional allowance is included for 
animals that might be affected by the sound sources other than the 
airguns.
    The potential number of occasions when members of each species 
might be exposed to received levels 160 dB re 1 microPa (rms) was 
calculated for each of three water depth categories (<100 m (328 ft), 
100-1000 m (328-3,280 ft), and >1000 m (>3,280 ft)) within the two 
survey areas (south of 75[deg] N. ``near Barrow'' and north of 75[deg] 
N. ``polar pack'') by multiplying
     the expected species density, either ``average'' (i.e., 
best estimate) or ``maximum'', corrected as described above,
     the anticipated line-kilometers of operations with both 
the 4-GI and 8-airgun array in each water-depth category after applying 
a 25 percent allowance for possible additional line kilometers as noted 
earlier,
     the cross-track distances within which received sound 
levels are predicted to be 160 dB for each water-depth category (2 X 
the 160 dB safety radii).
    Unlike other species whose ``best'' and ``maximum'' density 
estimates were multiplied by the entire trackline within each of the 
two portions of the project area (``near Barrow'' and ``polar pack'') 
to estimate exposures, gray whale and walrus densities were only 
multiplied by the proposed seismic trackline in water depths <200 m 
(<656 ft) along the final SW leg of the survey, south of 75[deg] N. 
Gray whales tend to remain in the shallow, nearshore waters of the 
Chukchi Sea and rarely occur in the Beaufort Sea. Basing exposures on 
the entire SW seismic trackline south of 75[deg] N should somewhat 
overestimate the number of gray whales that may be encountered while 
conducting seismic operations.
    Based on this method, the ``best'' and ``maximum'' estimates of the 
numbers of marine mammal exposures to airgun sounds with received 
levels 160 dB re 1 microPa (rms) were obtained using the average and 
``maximum'' densities from Tables 1, and are presented in Table 1. 
Using these calculations, for some species zero individuals were 
expected to be exposed to 160 dB. Since they are occasionally seen, 
however, UTIG increased the requested take to 5 to allow for the 
unlikely chance that they are encountered and exposed to 160 dB (Table 
1). Additional information regarding how these estimated take numbers 
were calculated is available in the application.

Potential Effects on Habitat

    The proposed seismic survey will not result in any permanent impact 
on habitats used by marine mammals, or to the food sources they 
utilize. Although feeding bowhead whales may occur in the area, the 
proposed activities will be of short duration in any particular area at 
any given time; thus any effects would be localized and short-term. The 
main impact issue associated with the proposed activity will be 
temporarily elevated noise levels and the associated direct effects on 
marine mammals.
    One of the reasons for the adoption of airguns as the standard 
energy source for marine seismic surveys was that, unlike explosives, 
they do not result in any appreciable fish kill. However, the existing 
body of information relating to the impacts of seismic on marine fish 
and invertebrate species is very limited.
    In water, acute injury and death of organisms exposed to seismic 
energy depends primarily on two features of the sound source: (1) the 
received peak pressure, and (2) the time required for the pressure to 
rise and decay (Hubbs and Rechnitzer, 1952 in Wardle et al., 2001). 
Generally, the higher the received pressure and the less time it takes 
for the pressure to rise and decay, the greater the chance of acute 
pathological effects. Considering the peak pressure and rise/decay time 
characteristics of seismic airgun arrays used today, the pathological 
zone for fish and invertebrates would be expected to be within a few 
meters of the seismic source (Buchanan et al., 2004). For the proposed 
survey, any injurious effects on fish would be limited to very short 
distances.
    The only designated Essential Fish Habitiat (EFH) species that may 
occur in the area of the project during the seismic survey are salmon 
(adult), and their occurrence in waters >150 km (93 mi) north of the 
Alaska coast is highly unlikely. Adult fish near seismic operations are 
likely to avoid the source, thereby avoiding injury. No EFH species 
will be present as very early life stages when they would be unable to 
avoid seismic exposure that could otherwise result in minimal 
mortality.
    The proposed Arctic Ocean seismic program for 2006 is predicted to 
have negligible to low physical effects on the various life stages of 
fish and invertebrates for its approximately 40 day duration and 3625-
km (2,252-mi) extent and will not result in any permanent impact on 
habitats used by marine mammals, or to the food sources they use. 
Nonetheless, the main impact issue associated with the proposed 
activities will be temporarily elevated noise levels and the associated 
direct effects on marine mammals, as discussed above.
    During the seismic study 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. 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. Although the main summering area for bowheads is in the 
Canadian Beaufort Sea, at least a few feeding bowhead whales may occur 
in offshore waters of the western Beaufort Sea and northern Chukchi Sea 
in July and August, when the Healy will be in the area. A reaction by 
zooplankton to a seismic impulse would only be

[[Page 28010]]

relevant to whales if it caused a concentration 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 that could cause significant or long-term consequences 
for individual marine mammals or their populations, since operations at 
the various sites will be limited in duration.

Potential Effects on Subsistence Use of Marine Mammals

    Subsistence hunting and fishing continue to be prominent in the 
household economies and social welfare of some Alaskan residents, 
particularly among those living in small, rural villages (Wolfe and 
Walker, 1987). Subsistence remains the basis for Alaska Native culture 
and community. In rural Alaska, subsistence activities are often 
central to many aspects of human existence, including patterns of 
family life, artistic expression, and community religious and 
celebratory activities. The National Science Foundation offers 
guidelines for science coordination with native Alaskans at http://www.arcus.org/guidelines/.
    Marine mammals are legally hunted in Alaskan waters near Barrow by 
coastal Alaska Natives; species hunted include bowhead whales, beluga 
whales, ringed, spotted, and bearded seals, walrus, and polar bears. In 
the Barrow area, bowhead whales provided approximately 69 percent of 
the total weight of marine mammals harvested from April 1987 to March 
1990. During that time, ringed seals were harvested the most on a 
numerical basis (394 animals).
    Bowhead whale hunting is the key activity in the subsistence 
economies of Barrow and two smaller communities to the east, Nuiqsut 
and Kaktovik. The whale harvests have a great influence on social 
relations by strengthening the sense of Inupiat culture and heritage in 
addition to reinforcing family and community ties.
    An overall quota system for the hunting of bowhead whales was 
established by the International Whaling Commission in 1977. The quota 
is now regulated through an agreement between NMFS and the Alaska 
Eskimo Whaling Commission (AEWC). The AEWC allots the number of bowhead 
whales that each whaling community may harvest annually (USDI/BLM 
2005).
    The community of Barrow hunts bowhead whales in both the spring and 
fall during the whales' seasonal migrations along the coast. Often, the 
bulk of the Barrow bowhead harvest is taken during the spring hunt. 
However, with larger quotas in recent years, it is common for a 
substantial fraction of the annual Barrow quota to remain available for 
the fall hunt. The communities of Nuiqsut and Kaktovik participate only 
in the fall bowhead harvest. The spring hunt at Barrow occurs after 
leads open due to the deterioration of pack ice; the spring hunt 
typically occurs from early April until the first week of June. The 
fall migration of bowhead whales that summer in the eastern Beaufort 
Sea typically begins in late August or September. The location of the 
fall subsistence hunt depends on ice conditions and (in some years) 
industrial activities that influence the bowheads movements as they 
move west (Brower, 1996). In the fall, subsistence hunters use aluminum 
or fiberglass boats with outboards. Hunters prefer to take bowheads 
close to shore to avoid a long tow during which the meat can spoil, but 
Braund and Moorehead (1995) report that crews may (rarely) pursue 
whales as far as 80 km. The autumn hunt at Barrow usually begins in 
mid-September, and mainly occurs in the waters east and northeast of 
Point Barrow. The whales have usually left the Beaufort Sea by late 
October (Treacy, 2002a,b).
    The scheduling of this seismic survey has been discussed with 
representatives of those concerned with the subsistence bowhead hunt, 
most notably the AEWC and the Barrow Whaling Captains' Association,. 
For this among other reasons, the project has been scheduled to 
commence in mid-July and terminate approximately 25 August, before the 
start of the fall hunt at Barrow (or Nuiqsut or Kaktovik), to avoid 
possible conflict with whalers.
    Although the timing of the Healy's seismic survey may overlap with 
potential subsistence harvest of beluga whales, ringed seals, spotted 
seals, or bearded seals, the hunting takes place well inshore of the 
proposed survey, which is to start >150 km (93 mi) offshore and 
terminate >200 km (124 mi) offshore.
    NMFS does not anticipate any unmitigable adverse impacts on the 
subsistence hunt of these species or stocks to result from the proposed 
Healy seismic survey.

Plan of Cooperation

    UTIG and the AEWC will develop a ``Plan of Cooperation'' for the 
2006 Arctic Ocean seismic survey, in consultation with representatives 
of the Barrow whaling community. UTIG is working with the people of 
Barrow to identify and avoid areas of potential conflict. The proposed 
plan has been presented to and discussed with the Whaling Captains' 
Association's, local residents, the AEWC, and the biologists in North 
Slope Borough Department of Wildlife Management.
    A Barrow resident knowledgeable about the mammals and fish of the 
area is expected to be included as a member of the MMO team aboard the 
Healy. Although his primary duties will be as a member of the MMO team 
responsible for implementing the monitoring and mitigation 
requirements, he will also be able to act as liaison with hunters and 
fishers if they are encountered at sea. However, the proposed activity 
has been timed so as to avoid overlap with the main harvests of marine 
mammals (especially bowhead whales), and is not expected to affect the 
success of subsistence fishers.
    The Plan of Cooperation will cover the initial phases of UTIG's 
Arctic Ocean seismic survey planned to occur 15 July to 25 August. The 
purpose of this plan will be to identify measures that will be taken to 
minimize any adverse effects on the availability of marine mammals for 
subsistence uses, and to ensure good communication between the project 
scientists and the community of Barrow.
    Subsequent meetings with whaling captains, other community 
representatives, the AEWC, NSB, and any other parties to the plan will 
be held as necessary to negotiate the terms of the plan and to 
coordinate the planned seismic survey operation with subsistence 
whaling activity.
    The proposed Plan of Cooperation may address the following:
     Operational agreement and communications procedures
     Where/when agreement becomes effective
     General communications scheme
     On-board Inupiat observer
     Conflict avoidance
     Seasonally sensitive areas
     Vessel navigation
     Air navigation
     Marine mammal monitoring activities
     Measures to avoid impacts to marine mammals
     Measures to avoid conflicts in areas of active whaling
     Emergency assistance
     Dispute resolution process
    As noted above, in the unlikely event that subsistence hunting or 
fishing is occurring within 5 km (3 mi) of the Healy's trackline, the 
airgun operations

[[Page 28011]]

will be suspended until the Healy is >5 km (3 mi) away.

Mitigation

    For the proposed seismic survey in the Arctic Ocean, UTIG will 
deploy airgun sources involving 4 GI guns or 8 airguns. These sources 
will be small-to-moderate in size and source level, relative to airgun 
arrays typically used for industry seismic surveys. However, the 
airguns comprising the arrays will be clustered with only limited 
horizontal separation, so the arrays will be less directional than is 
typically the case with larger airgun arrays, which will result in less 
downward directivity than is often present during seismic surveys, and 
more horizontal propagation of sound.
    Several important mitigation measures have been built into the 
design of the project:
     The project is planned for July-August, when few bowhead 
whales are present and no bowhead hunting is occurring;
     Airgun operations will be limited to offshore waters, far 
from areas where there is subsistence hunting or fishing, and in waters 
where marine mammal densities are generally low;
     When operating in shallower parts of the study area, 
airgun operations will be limited to the smaller source (4 GI guns);
    In addition to these mitigation measures that are built into the 
general design, several specific mitigation measures will be 
implemented to avoid or minimize effects on marine mammals encountered 
along the tracklines and are discussed below.
    Vessel-based observers will monitor marine mammals near the seismic 
source vessel during all airgun operations. These observations will 
provide the real-time data needed to implement some of the key 
mitigation measures. When marine mammals are observed within, or about 
to enter, designated safety zones (see below) where there is a 
possibility of significant effects on hearing or other physical 
effects, airgun operations will be powered down (or shut down if 
necessary) immediately. Vessel-based observers will watch for marine 
mammals near the seismic vessel during all periods of shooting and for 
a minimum of 30 min prior to the planned start of airgun operations 
after an extended shut down. Due to the timing of the survey situated 
at high latitude, the project will most likely take place during 
continuous daylight and monitoring adjustments will not be necessary 
for nighttime (darkness).
    In addition to monitoring, mitigation measures that will be adopted 
will include (1) speed or course alteration, provided that doing so 
will not compromise operational safety requirements, (2) power down or 
shut-down procedures, and (3) no start up of airgun operations unless 
the full 180 dB safety zone is visible for at least 30 min during day 
or night.

Speed or Course Alteration

    If a marine mammal is detected outside the safety radius and, based 
on its position and the relative motion, is likely to enter the safety 
radius, the vessel's speed and/or direct course may, when practical and 
safe, be changed in a manner that also minimizes the effect on the 
planned science objectives. The marine mammal activities and movements 
relative to the seismic vessel will be closely monitored to ensure that 
the marine mammal does not approach within the safety radius. If the 
mammal appears likely to enter the safety radius, further mitigative 
actions will be taken, i.e., either further course alterations or power 
down or shut down of the airgun(s). However, in regions of complete ice 
cover, which are common north of 75[deg] N., cetaceans are unlikely to 
be encountered because they must reach the surface to breathe.

Power-down Procedures

    A power-down involves decreasing the number of airguns in use such 
that the radius of the 180-dB zone is decreased to the extent that 
marine mammals are no longer within the 180-dB safety radius. A power 
down may also occur when the vessel is moving from one seismic line to 
another. During a power down, one airgun (or some other number of 
airguns less than the full airgun array) is operated. The continued 
operation of one airgun is intended to alert marine mammals to the 
presence of the seismic vessel in the area. In contrast, a shut down 
occurs when all airgun activity is suspended.
    If a marine mammal is detected outside the safety radius but is 
likely to enter the safety radius, and if the vessel's speed and/or 
course cannot be changed to avoid having the mammal enter the safety 
radius, the airguns may (as an alternative to a complete shut down) be 
powered down before the mammal is within the safety radius. Likewise, 
if a mammal is already within the safety zone when first detected, the 
airguns will be powered down if the power-down results in the animal 
being outside of the 180-dB isopleth, else the airguns will be shut 
down. During a power-down of the 4- or 8-airgun array, one airgun 
(either a single 105 in3 GI gun or one 210 in3 G. gun, respectively) 
will be operated. If a marine mammal is detected within or near the 
smaller safety radius around that single airgun (see Table 2), it will 
be shut down as well (see next subsection).
    Following a power-down, airgun activity will not resume until the 
marine mammal has cleared the safety zone. The animal will be 
considered to have cleared the safety zone if it: is visually observed 
to have left the safety zone; or has not been seen within the zone for 
15 min in the case of small odontocetes and pinnipeds; or has not been 
seen within the zone for 30 min in the case of mysticetes (large 
odontocetes do not occur within the study area).
    Because of the expanded shut-down radii proposed by UTIG (below), 
power-downs will only be used in deep water. In shallow and 
intermediate depth water, an immediate shutdown will occur when marine 
mammals are sighted within the designated safety radii.

Shut-down Procedures

    The operating airgun(s) will be shut down completely if a marine 
mammal approaches or enters the then-applicable safety radius and a 
power down is not practical (or shut down is specifically prescribed, 
see expanded shut down radii in Table 1). The operating airgun(s) will 
also be shut down completely if a marine mammal approaches or enters 
the estimated safety radius around the source that would be used during 
a power down.
    After submitting their application, UTIG proposed expanded shut 
down zones for shallow and intermediate depth water. As reflected in 
Table 1, in shallow or intermediate depth water, the Healy will cease 
operating airguns if a cetacean is seen at any distance from the vessel 
(most likely maximum visibility 2-3 km (1.2-1.9 mi)). For pinnipeds, in 
shallow water the Healy will implement a 1000-m (3,280-ft) shut-down 
zone, and for intermediate depth water, the Healy will implement a 500-
m (1,640-ft) shut-down zone.

Ramp-up Procedures

    A ``ramp-up'' procedure will be followed when the airgun array 
begins operating after a specified-duration period without airgun 
operations. NMFS normally requires that the rate of ramp up be no more 
than 6 dB per 5 min period. The specified period depends on the speed 
of the source vessel and the size of the airgun array that is being 
used. Ramp-up will begin with one of the G. guns (210 in\3\) or one of 
the Bolt airguns (500 in\3\) for the 8-airgun array, or one of the 105 
in\3\ GI

[[Page 28012]]

guns for the 4-GI gun array. One additional airgun will be added after 
a period of 5 minutes. Two more airguns will be added after another 5 
min, and the last four airguns (for the 8-airgun array) will all be 
added after the final 5 min period. During the ramp-up, the safety zone 
for the full airgun array in use at the time will be maintained.
    If the complete 180-dB safety radius has not been visible for at 
least 30 min prior to the start of operations, ramp up will not 
commence unless at least one airgun has been operating during the 
interruption of seismic survey operations. This means that it will not 
be permissible to ramp up the 4-GI gun or 8-airgun source from a 
complete shut down in thick fog or darkness (which may be encountered 
briefly in late August); when the outer part of the 180 dB safety zone 
is not visible. If the entire safety radius is visible, then start up 
of the airguns from a shut down may occur at night (if any periods of 
darkness are encountered during seismic operations). If one airgun has 
operated during a power-down period, ramp up to full power will be 
permissible in poor visibility, on the assumption that marine mammals 
will be alerted to the approaching seismic vessel by the sounds from 
the single airgun and could move away if they choose. Ramp up of the 
airguns will not be initiated during the day or at night if a marine 
mammal has been sighted within or near the applicable safety radii 
during the previous 15 or 30 min, as applicable.
    Airgun activity will not resume until the marine mammal has cleared 
the safety radius. The animal will be considered to have cleared the 
safety radius if it is visually observed to have left the safety 
radius, or if it has not been seen within the radius for 15 min (small 
odontocetes and pinnipeds) or 30 min (mysticetes).

Helicopter Flights

    The use of a helicopter to deploy and retrieve SISs during the 
survey is expected, at most, to cause brief behavioral reactions of 
marine mammals. To limit disturbance to marine mammals, helicopters 
will follow the survey track line. UTIG would avoid landing within 1000 
ft (304 m) of an observed marine mammal, and maintain a minimum 
altitude of 1000 ft (304 m), unless weather or other circumstances 
require a closer landing for human safety. For efficiency, each 
helicopter excursion will be scheduled to deploy/retrieve three or four 
SIS units. This will minimize the number of flights and the number of 
potential distubances to marine mammals in the area.

Monitoring

    UTIG proposes to sponsor marine mammal monitoring during the 
present project, in order to implement the proposed mitigation measures 
that require real-time monitoring, and to satisfy the anticipated 
monitoring requirements of the IHA.
    Vessel-based observers will monitor marine mammals near the seismic 
source vessel during all seismic operations. There will be little or no 
darkness during this cruise. Airgun operations will be shut down when 
marine mammals are observed within, or about to enter, designated 
safety radii (see below) where there is a possibility of significant 
effects on hearing or other physical effects. Vessel-based MMOs will 
also watch for marine mammals near the seismic vessel for at least 30 
min prior to the planned start of airgun operations after an extended 
shut down of the airgun. When feasible, observations will also be made 
during daytime periods without seismic operations (e.g., during 
transits and during coring operations).
    During seismic operations in the Arctic Ocean, four observers will 
be based aboard the vessel. MMOs will be appointed by UTIG with NMFS 
concurrence. A Barrow resident knowledgeable about the mammals and fish 
of the area is expected to be included as one of the team of marine 
mammal observers (MMOs) aboard the Healy. At least one observer, and 
when practical, two observers, will monitor marine mammals near the 
seismic vessel during ongoing operations and nighttime start ups (if 
darkness is encountered in late August). Use of two simultaneous 
observers will increase the proportion of the animals present near the 
source vessel that are detected. MMO(s) will normally be on duty in 
shifts of duration no longer than 4 hours. The USCG crew will also be 
instructed to assist in detecting marine mammals and implementing 
mitigation requirements (if practical). Before the start of the seismic 
survey the crew will be given additional instruction on how to do so.
    The Healy is a suitable platform for marine mammal observations. 
When stationed on the flying bridge, the eye level will be 
approximately 27.7 m (91 ft) above sea level, and the observer will 
have an unobstructed view around the entire vessel. If surveying from 
the bridge, the observer's eye level will be 19.5 m (64 ft) above sea 
level and approximately 25[deg] of the view will be partially 
obstructed directly to the stern by the stack (Haley and Ireland, 
2006). The MMO(s) will scan the area around the vessel systematically 
with reticle binoculars (e.g., 7 50 Fujinon), Big-eye binoculars (25 
150), and with the naked eye. During any periods of darkness (minimal, 
if at all, in this cruise), NVDs will be available (ITT F500 Series 
Generation 3 binocular-image intensifier or equivalent), if and when 
required. The survey will take place at high latitude in the summer 
when there will be continuous daylight, but night (darkness) is likely 
to be encountered briefly at the southernmost extent of the survey in 
late August. Laser rangefinding binoculars (Leica LRF 1200 laser 
rangefinder or equivalent) will be available to assist with distance 
estimation; these are useful in training observers to estimate 
distances visually, but are generally not useful in measuring distances 
to animals directly.
    To assure prompt implementation of shut downs, additional channels 
of communication between the MMOs and the airgun technicians will be 
established in 2006 as compared with the arrangements on the Healy in 
2005 (cf. Haley and Ireland, 2006). During power downs and shut downs, 
the MMO(s) will continue to maintain watch to determine when the 
animal(s) are outside the safety radius. Airgun operations will not 
resume until the animal is outside the safety radius. The animal will 
be considered to have cleared the safety radius if it is visually 
observed to have left the safety radius, or if it has not been seen 
within the radius for 15 min (small odontocetes and pinnipeds) or 30 
min (mysticetes).
    All observations and airgun power or shut downs will be recorded in 
a standardized format. Data will be entered into a custom database 
using a notebook computer. The accuracy of the data entry will be 
verified by computerized validity data checks as the data are entered 
and by subsequent manual checking of the database. These procedures 
will allow initial summaries of data to be prepared during and shortly 
after the field program, and will facilitate transfer of the data to 
statistical, graphical, or other programs for further processing and 
archiving.
    Results from the vessel-based observations will provide
    1.The basis for real-time mitigation (airgun power or shut down).
    2.Information needed to estimate the number of marine mammals 
potentially taken by harassment, which must be reported to NMFS.
    3.Data on the occurrence, distribution, and activities of marine 
mammals in the area where the seismic study is conducted.

[[Page 28013]]

    4.Information to compare the distance and distribution of marine 
mammals relative to the source vessel at times with and without seismic 
activity.
    5.Data on the behavior and movement patterns of marine mammals seen 
at times with and without seismic activity.

Reporting

    A report will be submitted to NMFS within 90 days after the end of 
the cruise. The report will describe the operations that were conducted 
and the marine mammals that were detected near the operations. The 
report will be submitted to NMFS, providing full documentation of 
methods, results, and interpretation pertaining to all monitoring. The 
90-day report will summarize the dates and locations of seismic 
operations, and all marine mammal sightings (dates, times, locations, 
activities, associated seis-mic survey activities). The report will 
also include estimates of the amount and nature of the impacts on 
marine mammals resulting from the seismic survey. Analysis and 
reporting conventions will be consistent with those for the 2005 Healy 
cruise to factilitate comparisons and (where appropriate) pooling of 
data across the two seasons.

Endangered Species Act

    Pursuant to section 7 of the ESA, the National Science Foundation 
(NSF) has begun consultation on this proposed seismic survey. NMFS will 
also consult on the issuance of an IHA 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)

    NSF prepared a Draft Environmental Assessment of a Marine 
Geophysical Survey by the USCG Healy of the Western Canada Basin, 
Chukchi Borderland and Mendeleev Ridge, Arctic Ocean, July-August 2006. 
NMFS will either adopted NSF's EA or prepare their own NEPA document 
prior to the issuance of an IHA. A copy of the EA is available at the 
NMFS website (see ADDRESSES).

Preliminary Conclusions

    NMFS has preliminarily determined that the impact of conducting the 
seismic survey in the Arctic Ocean may result, at worst, in a temporary 
modification in behavior (Level B Harassment) of small numbers, 
relative to the population sizes, of certain species of marine mammals. 
The maximum estimates of take indicate that no more than 2.5 percent of 
the gray whale and ringed seal populations would be harassed, and no 
more than 1 percent of any of the other affected stocks. This activity 
is expected to result in a negligible impact on the affected species or 
stocks.
    To summarize the reasons stated previously in this document, this 
preliminary determination is supported by: (1) the likelihood that, 
given sufficient notice through slow ship speed and ramp-up, marine 
mammals are expected to move away from a noise source that is annoying 
prior to its becoming potentially injurious; (2) recent research that 
indicates that TTS is unlikely (at least in delphinids) until levels 
closer to 200-205 dB re 1 microPa are reached rather than 180 dB re 1 
microPa; (3) the fact that 200-205 dB isopleths would be well within 
100 m (328 ft) of the vessel; and (4) the likelihood that marine mammal 
detection ability by trained observers is close to 100 percent during 
daytime and remains high at night to that distance from the seismic 
vessel. As a result, no take by injury or death is anticipated, and the 
potential for temporary or permanent hearing impairment is very low and 
will be avoided through the incorporation of the proposed mitigation 
measures mentioned in this document.
    While the number of potential incidental harassment takes will 
depend on the distribution and abundance of marine mammals in the 
vicinity of the survey activity, the number of potential harassment 
takings is estimated to be small, and has been mitigated to the lowest 
level practicable through incorporation of the measures mentioned 
previously in this document.
    The proposed seismic program will not interfere with any legal 
subsistence hunts, since seismic operations will not be conducted in 
the same space and time as the hunts in subsistence whaling and sealing 
areas. Therefore, NMFS believes the issuance of an IHA for this 
activity will not have an unmitigable adverse effect on any marine 
mammal species or stocks used for subsistence purposes.

Proposed Authorization

    As a result of these preliminary determinations, NMFS proposes to 
issue an IHA to UTIG for conducting a seismic survey in the Arctic 
Ocean from July 15 - August 25, 2006, provided the previously mentioned 
mitigation, monitoring, and reporting requirements are incorporated.

    Dated: May 9, 2006.
Donna Wieting,
Deputy Director, Office of Protected Resources, National Marine 
Fisheries Service.
[FR Doc. 06-4520 Filed 5-12-06; 8:45 am]
BILLING CODE 3510-22-S