Small Takes of Marine Mammals Incidental to Specified Activities; Seismic Surveys in the Chukchi Sea off Alaska, 49418-49433 [06-7097]

Agencies

• DEPARTMENT OF COMMERCE
• National Oceanic and Atmospheric Administration

[Federal Register Volume 71, Number 163 (Wednesday, August 23, 2006)]
[Notices]
[Pages 49418-49433]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: 06-7097]


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DEPARTMENT OF COMMERCE

National Oceanic and Atmospheric Administration

[I.D. 071406A]


Small Takes of Marine Mammals Incidental to Specified Activities; 
Seismic Surveys in the Chukchi Sea off Alaska

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

ACTION: Notice of Issuance of an Incidental Harassment Authorization.

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SUMMARY: In accordance with regulations implementing the Marine Mammal 
Protection Act (MMPA) as amended, notification is hereby given that an 
Incidental Harassment Authorization (IHA) to take marine mammals, by 
harassment, incidental to conducting marine geophysical seismic 
surveys, on oil and gas lease blocks located on Outer Continental Shelf 
(OCS) waters in the Chukchi Sea. has been issued to GX Technology of 
Houston, Texas (GXT).

DATES: Effective from August 15, 2006, through December 31, 2006.

ADDRESSES: The application, a list of references used in this document, 
and/or the IHA are available by writing to P. Michael Payne, Chief, 
Permits, Conservation and Education Division, Office of Protected 
Resources, National Marine Fisheries Service, 1315 East-West Highway, 
Silver Spring, MD 20910-3225, or by telephoning one of the contacts 
listed here. A copy of the application, the IHA and/or the research 
monitoring plan is also available at: https://www.nmfs.noaa.gov/pr/
permits/incidental.htm#iha.
    A copy of the Minerals Management Service's (MMS) Programmatic 
Environmental Assessment (PEA) is available on-line at: https://
www.mms.gov/alaska/ref/pea_be.htm
    Documents cited in this document, that are not available through 
standard public (inter-library loan) access, may be viewed, by 
appointment, during regular business hours at this address.

FOR FURTHER INFORMATION CONTACT: Kenneth Hollingshead, Office of 
Protected Resources, NMFS, (301) 713-2289, ext 128.

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

[[Page 49419]]

intentional, taking of small numbers of marine mammals by U.S. citizens 
who engage in a specified activity (other than commercial fishing) 
within a specified geographical region if certain findings are made and 
either regulations are issued or, if the taking is limited to 
harassment, a notice of a proposed authorization is provided to the 
public for review.
    An authorization shall be granted if NMFS finds that the taking 
will have a negligible impact on the species or stock(s) and will not 
have an unmitigable adverse impact on the availability of the species 
or stock(s) for subsistence uses and 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 28, 2006, NMFS received an IHA application from GXT to 
take several species of marine mammals incidental to conducting a 
marine seismic survey in the Chukchi and Beaufort Seas. On March 31, 
2006, GXT notified NMFS that it would not be conducting surveys in the 
U.S. Beaufort Sea, but would instead conduct seismic surveys in the 
Canadian Exclusive Economic Zone (EEZ) in the Beaufort Sea.
    GXT plans to collect seismic reflection data that reveal the sub-
bottom profile for assessments of petroleum reserves in the area. 
Ultra-deep 2D lines such as those to be collected are used to better 
evaluate the evolution of the petroleum system at the basin level, 
including identifying source rocks, migration pathways, and play types. 
All planned geophysical data acquisition activities will be conducted 
by GXT. The geophysical survey will be performed from the M/V 
Discoverer (the original proposed action was for the M/V Discoverer II 
to conduct the seismic survey, see Comments and Responses).
    The M/V Discoverer will arrive in Dutch Harbor about June 1st where 
it will be resupplied and the crew will change in preparation for the 
beginning of seismic surveys in the Chukchi Sea. Depending on ice 
conditions, the vessel will mobilize to arrive off Cape Lisburne and 
begin survey data acquisition as soon as possible; the expected date is 
July 30, 2006, depending upon ice conditions. Two alternative schedule 
scenarios are planned depending on the seasonal ice conditions 
encountered in 2006.
    The first (and most likely) scenario entails operations beginning 
in the Chukchi Sea about July 30, 2006. Collection of seismic data will 
continue there until there is sufficient open water near Point Barrow 
and in the Alaskan Beaufort Sea to allow passage east into the Canadian 
Beaufort Sea. The M/V Discoverer will then leave the Chukchi Sea, 
traverse the Alaskan Beaufort Sea, and conduct surveys in the Canadian 
Beaufort Sea under GX Technology Canada Ltd. of Calgary, Alberta,. a 
company incorporated in Canada. Seismic operations will continue in the 
Canadian Beaufort Sea until all planned seismic lines have been 
completed, or new ice begins forming in the fall. The vessel will then 
return to the Chukchi Sea to complete any lines not previously 
surveyed, or until weather and sea ice force an end to the survey 
season, which is not expected to continue past November 30, 2006.
    The second scenario will occur only if sea ice in the Beaufort Sea 
does not move far enough offshore to allow the M/V Discoverer to travel 
to the Canadian Beaufort. In that case, the vessel will continue 
operations in the Chukchi Sea until all survey lines there are 
completed. The M/V Discoverer will then exit the area and transit to 
Dutch Harbor to de-mobilize. Helicopter operations are not planned as a 
part of the seismic survey and would occur only in the case of an 
emergency.
    The total seismic survey program, if it can be completed, will 
consist of a total of about 5302 km (3294.5 mi) of surveys, not 
including transits when the airguns are not operating. Water depths 
within the study area are 30-3800 m (98-12467 ft). Approximately 14 
percent of the survey (about 742 km (461 mi)) will occur in water 
depths greater than 500 m (1640 ft), 5 percent of the survey (about 265 
km (165 mi)) will be conducted in water 200-500 m (656-1640 ft) deep, 
and most (81 percent) of the survey (about 4295 km (2669 mi) ) will 
occur in water less than 200 m (656 ft). None of the survey will take 
place in nearshore waters within 25 km (15.5 mi) of the coast (the 
Chukchi polynya zone).
    The M/V Discoverer will tow an airgun array directly astern and a 
single hydrophone streamer up to 9 km long. The array will consist of 
36 sleeve airguns (8 40 in\3\, 4 70 in3, 4 80 in\3\, 12 100 in\3\, and 
8 150 in\3\) that produce a total discharge of 3320 in\3\. The vessel 
will travel along pre-determined lines at about 4-5 knots while the 
airgun array discharges about every 20 seconds (shot interval about 46 
m (151 ft). The towed hydrophone streamer will receive the reflected 
signals and transfer the data to an on-board processing system. The 
proposed survey lines cover a large portion of the Chukchi Sea, and tie 
together known wells, core locations, fault lines and other geophysical 
points of interest. Specifications of the M/V Discoverer and the 36-
airgun array that will be used can be found in GXT's application 
(Appendices A and B; see ADDRESSES).
    The survey consists of a large grid of 14 lines oriented to connect 
previous well locations and core sample locations as well as geological 
structures in the sub-surface. The extent of the lines allows 
flexibility to mitigate any interaction with seasonal subsistence 
hunting as well as species migration patterns. GXT has restricted its 
survey lines along the shore to the area of the MMS lease sales 
(greater than 25 km (15.5 mi) offshore) to exclude the nearshore 
Chukchi polynya, through which marine mammals migrate in the spring. 
Lines will be chosen based on marine mammal migration and subsistence 
hunting, as well as ice movement and geophysical importance. If heavy 
ice conditions are encountered in the northern portions of the survey 
area, some trackline planned for that region may be shifted to ice-free 
waters within the central or southern portions of the survey area. 
There will be additional seismic operations associated with airgun 
testing, start up, and repeat coverage of any areas where initial data

[[Page 49420]]

quality is sub-standard. In addition to the airgun array, a pinger 
system will be used to position the 36-airgun array and streamer 
relative to the vessel.
    The M/V Discoverer will serve as the platform from which vessel-
based marine mammal observers will watch for marine mammals before and 
during airgun operations (see Mitigation and Monitoring later in this 
document). A ``chase boat'' will be used to protect the streamer from 
damage and otherwise lend support to the M/V Discoverer. It will not be 
introducing sounds into the water beyond those associated with normal 
vessel operations.

Characteristics of Airgun Pulses

    Discussion of the characteristics of airgun pulses was provided in 
several previous Federal Register documents (see 69 FR 31792 (June 7, 
2004) or 69 FR 34996 (June 23, 2004)) and is not repeated here. 
Additional information can be found in the MMS PEA and Appendix C in 
GXT's application. Reviewers are encouraged to read these documents for 
additional information.

Safety Radii

    The rms (root mean square) received sound pressure levels (SPLs) 
that are used to estimate marine mammal takes and establish safety 
zones for mitigation are not directly comparable to the peak or peak-
to-peak values normally used by geophysicists to characterize source 
levels of airguns (GXT IHA Application, Appendix C). 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 and by NMFS. A measured broadband received level of 160 dB 
re 1 microPa (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, 2000a). 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.
    Received sound fields have been modeled by GXT using the Gundalf 
software suite (Gundalf, 2002) for the 36-airgun array that will be 
used during this survey (GXT IHA Application Appendix B). GXT used an 
advanced version of the Gundalf modeling program to estimate the rms 
received sound levels (in dB re 1 microPa) at different distances from 
the seismic source on a broadband basis (0-256 Hz). These estimates are 
believed by GXT to be conservative (i.e., likely to overestimate the 
distance at which received levels will be [gteqt]160 dB) and most 
applicable to the 36-airgun array discharging 3320 in\3\ in water 
depths between 200 and 500 m (656-1640 ft), or ``intermediate depths.'' 
The safety radii are expected by GXT to be smaller in ``deep'' (greater 
than 500 m) and ``shallow'' (less than 200 m) water. Empirical data do 
not exist for this airgun array's sound propagation, so those data will 
be collected at the beginning of seismic operations. During this 
initial period, a 1.5X precautionary factor will be applied to the 190 
dB and 180 dB radii listed here in Table 1, for use as shutdown radii 
for marine mammals in the water. Once empirical measurements of the 
sound produced by GXT's airgun array have been collected and analyzed, 
the safety radii presented in Table 1 may be adjusted to reflect those 
results.
    As discussed in detail later in this document (see Mitigation), the 
airguns will be powered down immediately (or shut down if necessary) 
when cetaceans or pinnipeds are detected within or about to enter the 
[gteqt]180 dB or [gteqt]190 dB radii, respectively. A single 40 in\3\ 
sleeve airgun will be used as the power down source. The 160-190 dB re 
1 microPa (rms) radii for this source will be measured during acoustic 
verification measurements at the beginning of seismic shooting.
[GRAPHIC] [TIFF OMITTED] TN23AU06.043


[[Page 49421]]



Comments and Responses

    A notice of receipt of GXT's MMPA application and NMFS' proposal to 
issue an IHA to GXT was published in the Federal Register on June 6, 
2006 (71 FR 32045). That notice described, in detail, GXT's proposed 
activity, the marine mammal species that may be affected by the 
activity, and the anticipated effects on marine mammals. During the 30-
day public comment period on GXT's application, substantive comments 
were received from the Marine Mammal Commission (Commission), the 
Alaska Eskimo Whaling Commission (AEWC), the Center for Biological 
Diversity (CBD) and GXT. The comments of the Commission are identical 
to its comments on NMFS' proposed IHA to Shell. NMFS has addressed 
these comments in its Federal Register notice of issuance of that IHA 
and they are not repeated here. That notice will publish shortly. The 
CBD suggested that the comments submitted by the Natural Resources 
Defense Council on the PEA also be considered for the issuance of the 
IHA. These comments have been considered in the Final PEA and in NMFS' 
and MMS' Finding of No Significant Impact (FONSI) determinations. Many 
of those comments are specific to the PEA. However, where either of 
these sets of comments raise issues germane to the IHA issue that have 
not been addressed already, NMFS has addressed them either in this 
section or in notices of issuance of IHAs to Shell and ConocoPhillips 
(71 FR 43112, July 31, 2006).

Activity Concerns

    Comment 1: GXT notes that the source vessel for the planned seismic 
survey in the Chukchi Sea will be the M/V Discoverer, not the M/V 
Discoverer II. Because the M/V Discoverer is the sister-ship of the M/V 
Discoverer II, the two vessels are almost identical. The M/V Discoverer 
is 2 m (6.6 ft) longer, 2 m (6.6 ft) narrower, and its draft is 0.7 m 
(2.3 ft) less than the M/V Discoverer II. Because of the great 
similarities between the two vessels, the noise generated by the 
operations of each of the two sister-ships is expected to be 
approximately the same. The airgun array described in the notice is 
accurate for the M/V Discoverer.
    Response: NMFS has made the appropriate modifications to this 
document.

MMPA Concerns

    Comment 2: The CBD states that waters in the Canadian Beaufort EEZ 
are ``high seas'' and therefore GXT's activities there are subject to 
the take prohibition in section 102(a)(1) of the MMPA, 16 U.S.C. 
1372(a)(1). They cite the Center for Biological Diversity v. National 
Science Foundation, (2002 WL 31548073 (N.D. Cal, Oct 30, 2002).
    Response: MMPA section 102(a)(1) applies only to persons and 
vessels subject to the jurisdiction of the United States (16 U.S.C. 
1372(a)(1)). The vessel is Chinese-owned and flagged in the Bahamas, 
and there will be no person subject to the jurisdiction of the United 
States owning or operating the vessel while it is in the Canadian EEZ. 
Further, the persons responsible for the conduct of the seismic survey 
in the Canadian EEZ are not U.S. citizens (and the seismic work in the 
Canadian EEZ will be conducted under permits issued by the Canadian 
government to GX Technology Ltd of Calgary, Canada). Therefore, section 
102(a)(1) of the MMPA is irrelevant.
    Comment 3: The CBD also states that ``the MMPA prohibits any person 
to use ``any port, harbor, or other place'' under U.S. jurisdiction to 
take marine mammals. 16 U.S.C. 1372(a)(2)(B). Because GXT will start 
operations from Dutch Harbor, which is under U.S. jurisdiction, CBD 
believes this brings GXT's surveys in the Canadian Beaufort Sea within 
the jurisdictional reach of the MMPA.
    Response: We do not interpret the use of Dutch Harbor in this 
manner as falling within the meaning of 16 U.S.C. 1372(a)(2)(B). We 
also point out that the surveys in the Chukchi and Beaufort Seas are 
not one continuous survey. See also NMFS' response to Comment MMPAC1.
    Comment 4: The CBD believes that the proposed IHA does not 
adequately specify the specific geographic region where the activity 
will occur.
    Response: NMFS defines ``specified geographical region'' as ``an 
area within which a specified activity is conducted and which has 
certain biogeographic characteristics'' (50 CFR 216.103). NMFS believes 
that GXT's description of the activity and the locations for conducting 
seismic surveys meet the requirements of the MMPA. GXT intends to 
conduct seismic surveys within the area of the Chukchi Sea indicated in 
its application.

Marine Mammal Impact Concerns

    Comment 5: The CBD states that NMFS' failure to address the 
scientific literature linking seismic surveys with marine mammal 
stranding events, and the threat of serious injury or mortality renders 
NMFS' conclusionary determination that serious injury or mortality will 
not occur from GXT's activities arbitrary and capricious.
    Response: The evidence linking marine mammal strandings and seismic 
surveys remains tenuous at best. Two papers, Taylor et al. (2004) and 
Engel et al., (2004) reference seismic signals as a possible cause for 
a marine mammal stranding. Taylor et al. (2004) noted two beaked whale 
stranding incidents related to seismic surveys. The statement in Taylor 
et al. (2004) was that the seismic vessel was firing its airguns at 
1300 hrs on September 24, 2004 and that between 1400 and 1600 hrs, 
local fishermen found live-stranded beaked whales some 22 km (12 nm) 
from the ship's location. A review of the vessel's trackline indicated 
that the closest approach of the seismic vessel and the beaked whales 
stranding location was 18 nm (33 km) at 1430 hrs. At 1300 hrs, the 
seismic vessel was located 25 nm (46 km) from the stranding location. 
What is unknown is the location of the beaked whales prior to the 
stranding in relation to the seismic vessel, but the close timing of 
events indicates that the distance was not less than 18 nm (33 km). No 
physical evidence for a link between the seismic survey and the 
stranding was obtained. In addition, Taylor et al. (2004) indicates 
that the same seismic vessel was operating 500 km (270 nm) from the 
site of the Galapagos Island stranding in 2000. Whether the 2004 
seismic survey caused to beaked whales to strand is a matter of 
considerable debate (see Cox et al., 2004). NMFS believes that 
scientifically, these events do not constitute evidence that seismic 
surveys have an effect similar to that of mid-frequency tactical sonar. 
However, these incidents do point to the need to look for such effects 
during future seismic surveys. To date, follow-up observations on 
several scientific seismic survey cruises have not indicated any beaked 
whale stranding incidents.
    Engel et al. (2004), in a paper presented to the International 
Whaling Commission (IWC) in 2004 (SC/56/E28), mentioned a possible link 
between oil and gas seismic activities and the stranding of eight 
humpback whales (seven off the Bahia or Espirito Santo States and one 
off Rio de Janeiro, Brazil). Concerns about the relationship between 
this stranding event and seismic activity were raised by the 
International Association of Geophysical Contractors (IAGC). The IAGC 
(2004) argues that not enough evidence is presented in Engel et al. 
(2004) to assess whether or not the relatively high proportion of adult 
strandings in 2002 is anomalous. The

[[Page 49422]]

IAGC contends that the data do not establish a clear record of what 
might be a ``natural'' adult stranding rate, nor is any attempt made to 
characterize other natural factors that may influence strandings. As 
stated previously, NMFS remains concerned that the Engel et al. (2004) 
article appears to compare stranding rates made by opportunistic 
sightings in the past with organized aerial surveys beginning in 2001. 
If so, then the data are suspect.
    Second, strandings have not been recorded for those marine mammal 
species expected to be harassed by seismic in the Arctic Ocean. Beaked 
whales and humpback whales, the two species linked in the literature 
with stranding events with a seismic component are not located in the 
Chukchi Sea seismic areas. Finally, if bowhead and gray whales react to 
sounds at very low levels by making minor course corrections to avoid 
seismic noise and mitigation measures require GXT to ramp-up the 
seismic array to avoid a startle effect, strandings are highly unlikely 
to occur in the Arctic Ocean. In conclusion, NMFS does not expect any 
marine mammals will incur serious injury or mortality as a result of 
Arctic Ocean seismic surveys in 2006.
    Comment 6: The CBD states that the IHA notice provide no support 
for NMFS' ``conclusion'' on small numbers and negligible impact. For 
GXT's proposed seismic surveys in the Chukchi, the number of bowheads 
likely to be harassed is 337. In absolute terms these numbers cannot be 
considered ``small.'' Even relative to population size, the higher 
estimate represents a third of the estimated population of bowheads. 
For beluga whales, the number harassed is estimated to be 650; for gray 
whales the number is 481. None of these numbers can be considered 
``small.'' Given the MMPA is designed to protect not just populations, 
but individual marine mammals, any number in the hundreds or thousands 
simply cannot be considered ``small.
    Response: As discussed elsewhere in this document, NMFS believes 
that the small numbers requirement has been satisfied (see Estimates of 
Marine Mammal Exposures later in this document). The maximum number of 
bowhead whales that may be exposed to seismic sounds is estimated to be 
337 (Table 2). With a population size estimated to be 10,545 bowheads, 
NMFS estimates that the maximum percentage of the population that will 
be exposed would be approximately 3 percent, not 33 percent. For beluga 
whales and gray whales these numbers represent less than 5 percent of 
each population stock size.
    Also, NMFS must clarify that the numbers provided in Table 2 
estimate the numbers indicate the number of animals that would be 
exposed to seismic noise at the SPLs indicated, not the numbers of 
animals that will be taken by Level B (behavioral) harassment. Not all 
individuals of a marine mammal species would be expected to react at 
the same level or even react at all as indicated in GXT's application.
    Comment 7: The CBD notes that as many as 12,223 ringed seals and 
over 7000 bearded seals may be harassed in the Chukchi Sea. Bearded 
seals with over seven thousand to be harassed. The total numbers of 
marine mammals potentially harassed in the Chukchi from GXT's seismic 
surveys is almost twenty thousand individuals. These numbers cannot 
rationally be considered ``small.'' The proposed seismic surveys simply 
are not designed to avoid impacting more than small numbers of marine 
mammals and, therefore, the IHA must be denied.
    Response: NMFS is not required to consider the total estimated take 
across all species in making its small numbers determination. The 
species most likely to be harassed during seismic surveys in the Arctic 
Ocean area is the ringed seal, with a ``best estimate'' of animals 
being exposed to sound levels of 160 dB or greater of 3056 in the 
Chukchi Sea. As stated previously, this does not mean that this number 
of ringed seals will be taken by Level B harassment, it is only the 
best estimate of the number of animals that could be exposed to an SPL 
of 160 dB or greater and, theoretically could be harassed due to the 
noise. However, Moulton and Lawson (2002) indicate that most pinnipeds 
exposed to seismic sounds in the Beaufort Sea lower than 170 dB do not 
visibly react to that sound; pinnipeds are not likely to react to 
seismic sounds unless they are greater than 170 dB re 1 microPa (rms)). 
In addition, these estimates are calculated based upon line miles of 
survey effort, animal density and the calculated zone of influence 
(ZOI). While this methodology is valid for seismic surveys that 
transect long distances (as part of GXT's survey will be), those 
surveys that ``mow the lawn,'' that is, remain within a relatively 
small area, transiting back and forth while shooting seismic, numbers 
tend to be highly inflated. As a result, NMFS believes that these 
exposure estimates are conservative and may actually affect very few 
animals.
    Although it might be argued that the absolute number of ringed seal 
behavioral harassment numbers may not be small, the number of 
``exposures'' is relatively small, representing less than 4 percent of 
the regional population of that species (245,000) if each ``exposure'' 
represented an individual ringed seal and maximum ringed seal density 
was used. Bearded (and spotted) seals take estimates ignore the 
likelihood that these two species frequent polar ice areas where 
seismic vessels cannot operate and, therefore, likely overestimate take 
levels.
    Comment 8: The CBD believes that NMFS' assumption that sounds below 
160 dB do not constitute harassment is incorrect and, therefore, 
underestimates the possible true impact. The CBD notes that their NEPA 
comments pointed out numerous studies showing significant behavioral 
impacts from received sounds well below 160 dB and even the PEA 
acknowledges that impacts to bowheads occur at levels of 120 dB and 
below. This clearly meets the statutory definition of harassment and 
demonstrates that the numbers of marine mammals estimated to be taken 
by GXT's activity likely constitute a significant underestimate. NMFS' 
``small numbers'' conclusion is therefore arbitrary and capricious.
    Response: The best information available to date for reactions by 
bowhead whales to impulse noise, such as seismic, is based on the 
results from the 1998 aerial survey (as supplemented by data from 
earlier years) as reported in Miller et al. (1999). In 1998, bowhead 
whales below the water surface at a distance of 20 km (12.4 mi) from an 
airgun array received pulses of about 117-135 dB re 1 
microParms, depending upon propagation. Corresponding levels 
at 30 km (18.6 mi) were about 107-126 dB re 1 microParms. 
Miller et al. (1999) surmise that deflection may have begun about 35 km 
(21.7 mi) to the east of the seismic operations, but did not provide 
SPL measurements to that distance, and noted that sound propagation has 
not been studied as extensively eastward in the alongshore direction, 
as it has northward, in the offshore direction. Therefore, while this 
single year of data analysis indicates that bowhead whales may make 
minor deflections in swimming direction at a distance of 30-35 km 
(18.6-21.7 mi), there is no indication that the SPL where deflection 
first begins is at 120 dB, it could be at another SPL lower or higher 
than 120 dB. Miller et al. (1999) also note that the received levels at 
20-30 km (12.4-18.6 mi) were considerably lower in 1998 than have 
previously been shown to elicit avoidance in bowheads exposed to 
seismic pulses. However, the seismic airgun array used in 1998 was 
larger

[[Page 49423]]

than the ones used in 1996 and 1997 (1500 in\3\ vs 1320 in\3\). It 
should also be pointed out that these minor course changes are during 
migration and, as indicated in the Final PEA, have not been seen at 
other times of the year and during other activities. Therefore, until 
additional data is obtained to indicate at what SPL bowhead whales 
begin to deflect away from a seismic airgun array, NMFS will not adopt 
any single SPL value below 160 dB and apply it across the board for all 
species and in all circumstances. NMFS therefore continues to estimate 
``takings'' under the MMPA from impulse noises, such as seismic, as 
being at a distance of 160 dB (re 1 microPa).
    Comment 9: The CBD states that NMFS has no idea of the actual 
population status of several of the species subject to the proposed 
IHA. NMFS acknowledges (in its Status of Stock's Reports (SARS)) it has 
no accurate information on the status of spotted seals, bearded seals, 
and ringed seals. Without this data, NMFS cannot make a rational 
``negligible impact'' finding. This is particularly so given there is 
real reason to be concerned about the status of these populations. Such 
concerns were raised recently in a letter to NMFS from the Commission 
that cautioned against assuming a stable population given apparent 
changes in the Bering, Chukchi, and Beaufort Seas and the declines of 
many other Alaska marine mammals.
    Response: NMFS uses the best information available when making a 
determination that the impacts from an activity will have a negligible 
impact on the affected species and stocks of marine mammals. This 
information comes from many sources, including NMFS' SARS reports. As 
noted in GXT's application for the pinniped species mentioned by CBD:
    (1) Bearded seals: While no reliable estimate of bearded seal 
abundance is available for the Beaufort Sea (Angliss and Lodge, 2002), 
results from aerial surveys of the eastern Chukchi Sea indicated 
densities of up to 0.149 bearded seals/km\2\ and a population of 4862 
animals, although actual abundance may be much higher (Angliss and 
Lodge, 2004).
    (2) Spotted seals: While the total number of spotted seals in 
Alaskan waters is not known (Angliss and Lodge, 2002), the estimate is 
most likely between several thousand and several tens of thousands 
(Rugh et al., 1997).
    (3) Ringed seals: While no estimate for the size of the Alaska 
ringed seal stock is currently available (Angliss and Lodge, 2002), 
past ringed seal population estimates in the Bering-Chukchi-Beaufort 
area ranged from 1-1.5 million (Frost, 1985) to 3.3-3.6 million (Frost 
et al., 1988). Frost and Lowry (1981) estimated 80,000 ringed seals in 
the Beaufort Sea during summer and 40,000 during winter.
    At present, there is no scientific information that population 
declines are occurring or have occurred. Moreover, long-term monitoring 
studies of Alaskan marine mammals being conducted by NMFS and others 
would note significant population declines.

Cumulative Effects Concerns

    Comment 10: In its comments on NMFS' negligible impact 
determination, CBD states that NMFS must look at the immediate effects 
of GXT's seismic surveys together with the cumulative effects over 
multiple years of other oil and gas activities and anthropogenic risk 
factors such as climate change, both onshore and offshore Alaska. CBD 
contends that these cumulative effects should be analyzed with respect 
to their potential population consequences at the species level, stock 
level, and at the local population level, citing Anderson v. Evans, 371 
F.3d 475 (9th Cir. 2004).
    Response: Under section 101(a)(5)(D) of the MMPA, NMFS is required 
to determine whether the taking by the IHA applicant's specified 
activity will have a negligible impact on the affected marine mammal 
species or population stocks. Cumulative impact assessments are NMFS' 
responsibility under NEPA, not the MMPA. In that regard, the MMS' Final 
PEA addresses cumulative impacts, as did its Draft PEA. The PEA's 
cumulative activities scenario and cumulative impact analysis focused 
on oil and gas-related and non-oil and gas-related noise-generating 
events/activities in both Federal and State of Alaska waters that were 
likely and foreseeable. Other appropriate factors, such as Arctic 
warming, military activities and noise contributions from community and 
commercial activities were also considered. Appendix D of that PEA 
addresses similar comments on cumulative impacts, including global 
warming. That information is incorporated in this document by citation. 
NMFS has adopted the MMS Final PEA and it is part of NMFS' 
Administrative Record. Finally, the proposition for which CBD cites 
Anderson was in the context of the court's analysis under NEPA, not 
MMPA section 101(a)(5)(D), which was not at issue in Anderson.

Mitigation Concerns

    Comment 11: GXT suggests (as noted in section XI of GXT's IHA 
application) that the 190-dB radius, not the 180-dB radius, is the 
appropriate zone that should be fully visible to observers and clear of 
all marine mammal sightings for 30 minutes prior to ramp-up from a full 
shutdown of all airguns. This includes during night-time or other times 
of reduced visibility. The rationale for this is as follows:
    (1) Pinnipeds, to which the 190-dB safety zone applies, have not 
shown much avoidance of operating seismic arrays in the Beaufort Sea 
(Harris et al., 2001; Moulton and Lawson, 2002; Miller et al., 2005). 
Therefore, it is appropriate to assume that some pinnipeds will not 
move out of the safety zone during a ramp-up. Accordingly, the 190-dB 
zone should be visible before a ramp-up begins.
    (2) The types of cetaceans likely to be encountered (bowheads, 
belugas, and gray whales) have shown avoidance of active seismic 
surveys and it is expected that they will move beyond the full 180-dB 
radius for the airgun array during the ramp-up (Malme and Miles, 1985; 
Malme et al., 1986, 1988; Richardson et al., 1986, 1999; Miller et al. 
2005). Thus, it is not critical that the full 180-dB radius applicable 
to cetaceans be visible prior to commencing a ramp-up.
    Response: While NMFS fully expects that bowhead and beluga whales 
will avoid seismic activity by large distances, scientific information 
is less clear that the gray whales will do so. Documentation of 
avoidance in either the Beaufort or Chukchi seas is lacking and, 
although Malme et al. (1985) indicate that gray whales will avoid 
seismic activity, later research by Clark and Tyack (1999) duplicating 
the work of Malme et al. (1985) indicates that gray whale avoidance 
response is context dependent. Essentially, gray whales did not react 
(avoid) the sound source when the source was not directly in its 
migratory path. Also, because GXT will be conducting seismic operations 
in the Chukchi Sea where additional cetaceans may be affected (killer 
whales and harbor porpoise (although these species are more sensitive 
to higher frequencies than seismic)), NMFS has determined that the 
scientific evidence to support using only 190-dB isopleth as a safety 
zone for all species of marine mammals is not supportable at this time.
    Comment 12: The CBD believes that the proposed IHA notice ignores 
the MMPA statutory requirement that all methods and means of ensuring 
the least practicable impact have been adopted.
    Response: NMFS believes that the mitigation measures required under 
GXT's IHA will result in the least

[[Page 49424]]

practicable adverse impact. Inherent in implementing these mitigation 
measures is some level of uncertainty on the distribution and abundance 
of cetaceans in the Chukchi Sea and on whether the acoustic impacts 
observed in the Beaufort Sea also occur in the Chukchi Sea. Additional 
information on this concern can be found later in this document and in 
previous responses to this concern by CBD (see for example, comment 
MiC2 and MiC3 in Shell's IHA notice.

Monitoring Concerns

    Comment 13: The AEWC incorporates by reference into its comments on 
the GXT application, the comments submitted by the North Slope 
Borough's Department of Wildlife Management regarding the most recent 
version of the ``Marine Mammal Monitoring, Mitigation, and 
Investigatory Plan for Seismic Exploration in the Alaskan Chukchi Sea, 
2006'' (Monitoring Plan) prepared on behalf of Shell, ConocoPhillips 
and GXT.
    Response: Please see the discussion on marine mammal monitoring 
later in this document.

Subsistence Concerns

    Comment 14: The AEWC notes that GXT's proposed data acquisition in 
the Chukchi Sea includes work near shore, the AEWC is concerned about 
the potential effects on the fall bowhead whale subsistence hunt at 
Barrow and possibly Wainwright and Pt. Hope. The village of Barrow 
traditionally has hunted during both the spring and fall bowhead whale 
migraitons; however, unfavorable ice conditions in the Chukchi Sea this 
year resulted in a very poor spring bowhead whale hunt for all of the 
spring (hunt) villages. As a result, the villages of Wainwright and 
Point Hope have announced that they may attempt to hunt bowheads this 
fall.
    To protect the fall bowhead hunt at Barrow, the Conflict Avoidance 
Agreement (CAA) (see description later in this document) includes a 
prohibition on all seismic operations beginning on September 10th 
through October 25\th\, from Pitt Point on the east side of Smith Bay 
to the east to a location about half way between Barrow and Peard Bay 
to the west. However, given the outcome of the spring bowhead hunt in 
the Chukchi villages (which had not been completed at the time the CAA 
was negotiated), the AEWC requests NMFS' assistance in providing 
further protections for the near-shore areas of the Chukchi during the 
fall bowhead migration in this region. In particular, the AEWC requests 
NMFS include in GXT's IHA, provisions designed to protect the nearshore 
area from the effects of seismic operations, either directly or through 
sound propagation. The AEWC suggests that GXT refrain from conducting 
seismic operations within 50 miles of the Chukchi coast beginning 
September 15 through October 25\th\, from the halfway point between 
Barrow and Peard Bay to 50 miles due west of Cape Lisburne.
    Response: The IHA requires GXT to comply with the conditions of the 
CAA. This requirement ensures that, to the greatest extent practicable, 
GXT's activities will not have an unmitigable adverse impact on 
subsistence uses of marine mammals, particularly bowhead whales.
    Comment 15: The CBD disagrees with NMFS' ``no unmitigable adverse 
impact'' determination for the same reasons it disagrees with NMFS' 
``negligible impact'' and ``small numbers'' determinations.
    Response: This comment is not specific enough for a response, but 
we disagree with the conclusion.

Endangered Species Act (ESA) Concerns

    Comment 16: The CBD states that previous Biological Opinions for 
the bowhead whale have been inadequate. The CBD hopes NMFS will perform 
a full analysis required by law.
    Response: NMFS has issued a biological opinion regarding the 
effects of this action on ESA-listed species and critical habitat under 
the jurisdiction of NMFS. That biological opinion concluded that this 
action is not likely to jeopardize the continued existence of listed 
species or result in the destruction or adverse modification of 
critical habitat. A copy of the Biological Opinion is available upon 
request (see ADDRESSES).
    Comment 17: The CBD states that NMFS may authorize incidental take 
of bowhead whales under the ESA pursuant to section 7(b)(4), but only 
where such take occurs while ``carrying out an otherwise lawful 
activity.'' CBD believes GXT's proposed activities violate the MMPA and 
NEPA and therefore are not ``otherwise lawful.'' Any take authorization 
for the bowhead whale would therefore violate the ESA as well as other 
statutes.
    Response: NMFS believes it has complied with the requirements of 
the MMPA, the ESA and NEPA in connection with the incidental harassment 
of marine mammals by GXT while conducting activities permitted under 
MMS' jurisdiction.

NEPA Concerns

    Comment 18: The CBD notes that they submitted comments on the MMS 
PEA along with comments on GXT's IHA application. Subsequent to CBD's 
May 10, 2006 letter on the PEA, they believe additional information has 
come to light that requires the preparation of an EIS in accordance 
with 40 CFR 1508.27(b)(4). The CBD notes that the Native Village of 
Kaktovik passed a resolution opposing Shell's seismic survey plans and 
the Native Village of Point Hope also officially expressed its 
opposition to this summer's various seismic surveys. The CBD believes 
that NMFS cannot rationally adopt the PEA and make a FONSI on this 
action. Instead, it must prepare a full EIS analyzing the effects of 
Shell's proposed activities in the context of cumulative effects of all 
other natural and anthropogenic impacts on marine mammals, habitats and 
communities of the Chukchi and Beaufort seas.
    Response: While the Villages of Point Hope and Kaktovik expressed 
opposition to seismic activities (specifically by Shell) in the Chukchi 
and Beaufort seas this year (as coastal native Alaskan communities have 
done for many years), the Whaling Captains' Associations of Point Hope, 
Kaktovik, Nuiqsut, and Wainwright signed a CAA with Shell, 
ConocoPhillips and GXT. This CAA indicates to NMFS that seismic 
exploration activities by these companies will not have an unmitigable 
adverse impact on the availability of marine mammals for subsistence 
uses, including bowheads and belugas. This, along with the required 
mitigation and monitoring measures, informed NMFS' FONSI.

Description of Habitat and Marine Mammals Affected by the Activity

    A detailed description of the Chukchi Sea ecosystem and its 
associated marine mammals can be found in several documents, including 
the MMS PEA and does not need to be repeated here. The Chukchi Seas 
support a diverse assemblage of marine mammals, including bowhead 
whales (Balaena mysticetus), gray whales (Eschrichtius robustus), 
beluga whales (Delphinapterus leucas), killer whales (Orcinus orca), 
harbor porpoise (Phocoena phocoena), ringed seals (Phoca hispida), 
spotted seals (Phoca largha), bearded seals (Erignathus barbatus), 
walrus (Odobenus rosmarus) and polar bears (Ursus maritimus). These 
latter two species are under the jurisdiction of the U.S. Fish and 
Wildlife Service (USFWS) and are not discussed further in this 
document. Abundance estimates of these species can be found in Table 2 
in GXT's application. Descriptions of the biology and distribution of 
the marine mammal species under NMFS' jurisdiction can be

[[Page 49425]]

found in GXT's application, MMS' PEA, and several other documents 
(Corps of Engineers, 1999; Lentfer, 1988; MMS, 1992, 1996; Hill et al., 
1999). Information on marine mammal hearing capabilities can be found 
in GXT's application.
    Information on these species can also be found in NMFS Stock 
Assessment Reports. The Alaska stock assessment document is available 
at: https://www.nmfs.noaa.gov/pr/readingrm/MMSARS/sar2003akfinal.pdf. 
Updated species reports are available at: https://www.nmfs.noaa.gov/pr/
readingrm/MMSARS/2005alaskasummarySARs.pdf. Please refer to these 
documents for information on these species.

Potential Impacts of Seismic Surveys on Marine Mammals

    Disturbance by seismic noise is the principal means of taking by 
this activity. Support vessels and marine mammal survey aircraft (if 
required) may provide a potential secondary source of noise. The 
physical presence of vessels and aircraft could also lead to non-
acoustic effects on marine mammals involving visual or other cues.
    As outlined in several previous NMFS documents, the effects of 
noise on marine mammals are highly variable, and can be categorized as 
follows (based on Richardson et al., 1995):
    (1) The noise may be too weak to be heard at the location of the 
animal (i.e., lower than the prevailing ambient noise level, the 
hearing threshold of the animal at relevant frequencies, or both);
    (2) The noise may be audible but not strong enough to elicit any 
overt behavioral response;
    (3) The noise may elicit reactions of variable conspicuousness and 
variable relevance to the well being of the marine mammal; these can 
range from temporary alert responses to active avoidance reactions such 
as vacating an area at least until the noise event ceases;
    (4) Upon repeated exposure, a marine mammal may exhibit diminishing 
responsiveness (habituation), or disturbance effects may persist; the 
latter is most likely with sounds that are highly variable in 
characteristics, infrequent and unpredictable in occurrence, and 
associated with situations that a marine mammal perceives as a threat;
    (5) Any anthropogenic noise that is strong enough to be heard has 
the potential to reduce (mask) the ability of a marine mammal to hear 
natural sounds at similar frequencies, including calls from 
conspecifics, and underwater environmental sounds such as surf noise;
    (6) If mammals remain in an area because it is important for 
feeding, breeding or some other biologically important purpose even 
though there is chronic exposure to noise, it is possible that there 
could be noise-induced physiological stress; this might in turn have 
negative effects on the well-being or reproduction of the animals 
involved; and
    (7) Very strong sounds have the potential to cause temporary or 
permanent reduction in hearing sensitivity. In terrestrial mammals, and 
presumably marine mammals, received sound levels must far exceed the 
animal's hearing threshold for there to be any temporary threshold 
shift (TTS) in its hearing ability. For transient sounds, the sound 
level necessary to cause TTS is inversely related to the duration of 
the sound. Received sound levels must be even higher for there to be 
risk of permanent hearing impairment. In addition, intense acoustic or 
explosive events may cause trauma to tissues associated with organs 
vital for hearing, sound production, respiration and other functions. 
This trauma may include minor to severe hemorrhage.

Potential Effects of Seismic Airgun Arrays on Marine Mammals

    GXT believes that the effects of sounds from airguns might include 
one or more of the following: (1) Tolerance; (2) masking of natural 
sounds; (2) behavioral disturbance; and (3) at least in theory, hearing 
impairment and other non-auditory physical effects (Richardson et al., 
1995). Discussion on marine mammal tolerance to noise, masking effects 
of noise, temporary or permanent hearing impairment, and non-auditory 
effects can be found in GXT's IHA application, and previous Federal 
Register notices for seismic activities (e.g., see 69 FR 74906, 
December 14, 2004). In summary, NMFS and GXT believe that it is 
unlikely that there would be any cases of temporary or permanent 
hearing impairment, non-auditory physical effects, or strandings. NMFS 
has also provided information previously on the potential effects of 
noise on marine mammal species expected to be in the Chukchi Sea region 
(see 71 FR 26055 (May 3, 2006), 71 FR 27685 (May 12, 2006) and 71 FR 
32045 (June 6, 2006)). Readers are encouraged to review those documents 
for additional information.

Potential Effects of Pinger Signals on Marine Mammals

    A description of the pinger system (DigiRANGE I and II, Input/
Output, Inc) that will be used during seismic operations to position 
the airgun array and hydrophone streamer relative to the vessel was 
described in the proposed IHA notice for GXT June 6, 2006 (71 FR 32045) 
and is not repeated here.

Estimates of Marine Mammal Exposures to SPLs of 160 dB or Higher (Level 
B Harassment)

    Table 2 of this Federal Register notice provides the estimates of 
the number of potential sound exposure to levels 160 dB re 1 microPa 
(rms) or greater. The methodology used and the assumptions made to 
estimate incidental take by Level B harassment, at sound pressure 
levels at 160 dB or above, by seismic and the numbers of marine mammals 
that might be affected during the proposed seismic survey area in the 
Chukchi Sea are presented in the GXT application. While GXT believes, 
based on the evidence summarized in the application, that the 170-dB 
criterion is appropriate for estimating Level B harassment for 
delphinids and pinnipeds, which tend to be less responsive (whereas the 
160-dB criterion is considered relevant for other cetaceans), there is 
no empirical evidence to indicate that some delphinid species do not 
respond at the lower level (i.e., 160 dB). Also, since delphinids are 
not expected to be affected by this action, this suggested new 
criterion is not relevant for this action. While the application cites 
recent empirical information regarding responses of pinnipeds to low-
frequency seismic sounds, the information cited in the application is 
less than convincing. As a result, NMFS will continue to use the 160-dB 
isopleth to estimate the numbers of pinnipeds that may be taken by 
Level B harassment. However, while some autumn migrating bowheads in 
the Beaufort Sea have been found to react to a noise threshold closer 
to 130 dB re 1 microParms; (Miller et al., 1999; Richardson 
et al., 1999), evidence in Richardson et al. (1986) and Miller et al. 
(2005) indicate that the 160-dB criterion is suitable for summering 
bowhead whales.
    The following estimates are based on a consideration of the number 
of marine mammals that might be exposed to SPLs of 160 dB or more along 
about 5302 line-km (3294 line mi) of seismic surveys across the Chukchi 
Sea. An assumed total of 6628 km (4118 mi) of trackline in the Chukchi 
Sea includes a 25 percent allowance over and above the planned 
trackline to allow for turns and lines that might have to be repeated 
because of poor data quality, or for minor changes to the survey 
design.
    The anticipated radii of influence of the M/V Discoverer's pinger 
system are

[[Page 49426]]

much less than those for the airgun array (for those species that can 
hear it). It is assumed that, during simultaneous operations of the 
airgun array and pinger system, any marine mammals close enough to be 
affected by the pingers will already be affected by the airguns. 
However, whether or not the airguns are operating simultaneously with 
the pinger system, odontocetes and seals are expected to exhibit no 
more than momentary and inconsequential responses to the pingers, based 
on evidence of their reactions from pingers on maritime private and 
commercial vessels using similar instrumentation for obtaining 
bathymetric information. Therefore, no additional take numbers are 
provided for animals exposed to pingers.
    The estimates of marine mammals that might be exposed to SPLs that 
could result in Level B harassment are based on available data about 
mammal distribution and densities at different locations and times of 
the year. The proposed survey covers a large area in the Chukchi Sea in 
two different seasons. The estimates of marine mammal densities have 
therefore been separated both spatially and temporarily in an attempt 
to represent the distribution of animals expected to be encountered 
over the duration of the survey. Density estimates in the Chukchi Sea 
have been derived for two time periods, the early summer period 
covering the months of June and July (Table 3 in GXT's IHA 
application), and the late fall period including most of October and 
November (Table 4 in GXT's IHA application). For the Chukchi Sea, 
cetacean densities during the summer were estimated from effort and 
sighting data in Moore et al. (2000) and Richardson and Thomson (eds., 
2002), while pinniped densities were estimated from Bengtson (2005) and 
Moulton and Lawson (2002).
    The potential number of events when members of each species might 
be exposed to received levels 160 dB re 1 microPa (rms) or greater was 
calculated by summing the results for each season and habitat zone by 
multiplying:
    (1) The expected species density, either ``average'' (i.e., best 
estimate) or ``maximum'' (see Tables 3 and 4 in GXT's IHA application),
    (2) The anticipated total line-kilometers of operations with the 
36-airgun array in the time period, and habitat zone to which that 
density applies after applying a 25 percent allowance for possible 
additional line kilometers (see GXT IHA application) and
    (3) The cross-track distances within which received sound levels 
are predicted to be [gteqt]160 (Table 1 in this document).
    Some marine mammals that are estimated to be exposed, particularly 
migrating bowhead whales, might show avoidance reactions before being 
exposed to 160 dB re 1 microPa (rms). Thus, these calculations actually 
estimate the number of exposures to >160 dB that would occur if there 
were no earlier avoidance of the area ensonified to that level.
    For the 36-airgun array, the cross track distance is 2X the 
predicted 160-dB radius predicted by the Gundalf model or 6000 m (19685 
ft). Applying the approach described above, 55,560 km2 of open-water 
habitat in the Chukchi Sea would be within the 160-dB isopleth over the 
course of the seismic project (though not at any given moment). After 
adding the 25-percent contingency to the expected number of line 
kilometers of seismic run, the number of exposures is calculated based 
on 69,450 km2.
    The numbers of exposures in the two habitat categories (open water 
and ice margin) were then summed for each species. GXT's estimate of 
marine mammal exposures to SPL of 160 dB (and greater) is provided in 
Tables 5, 6, and 7 in the IHA application. Table 2 in this document is 
a summary of that information.

TABLE 2. Summary of the number of potential exposures of marine mammals to received sound levels in the water of
[gteqt]160 dB during GXT's proposed seismic program in the Chukchi Sea, Alaska, -15 June -25 July and -1 October
   - 30 November, 2006. Not all marine mammals will change their behavior when exposed to these sound levels,
                    although some might alter their behavior somewhat when levels are lower.
                                Number of Exposure to Sound Levels [gteqt]160 dB
----------------------------------------------------------------------------------------------------------------
                                         Summer                   Fall                        Total
----------------------------------------------------------------------------------------------------------------
            Species                Average     Maximum     Average    Maximum    Average          Maximum
----------------------------------------------------------------------------------------------------------------
Odontocetes                      ..........  ..........  ..........  .........  .........  .....................
  Monodontidae                   ..........  ..........  ..........  .........  .........  .....................
    Beluga                       3           11          160         639        163                         650
  Delphinidae                    ..........  ..........  ..........  .........  .........  .....................
  Killer whale                   3           11          5           22         8                            33
  Phocoenidae                    ..........  ..........  ..........  .........  .........  .....................
    Harbor porpoise              0           0           0           0          0                             0
Mysticetes                       ..........  ..........  ..........  .........  .........  .....................
    Bowhead whale                1           8           57          328        59                          337
    Gray whale                   1           4           83          333        84                          337
    Minke whale                  3           11          5           22         8                            33
    Fin whale                    1           2           1           4          2                             7
  Total Cetaceans                11          47          313         1349       324                        1396
Pinnipeds                        ..........  ..........  ..........  .........  .........  .....................
    Bearded seal                 586         2344        1190        4760       1776                       7104
    Spotted seal                 6           23          12          47         17                           70
    Ringed seal                  1008        4033        2047        8189       3056                      12223
    Harbor seal                  0           0           0           0          0                             0
                                 ..........  ..........  ..........  .........  .........  .....................
Total Pinnipeds                  1600        6401        3249        12996      4849                      19397
----------------------------------------------------------------------------------------------------------------


[[Page 49427]]

    GXT and NMFS believe that bowhead, beluga, and gray whales are the 
only cetaceans expected to be exposed to noise levels [gteqt]160-dB 
levels. The estimates show that one endangered cetacean species, the 
bowhead whale, is expected to be exposed to such noise levels, unless 
bowheads avoid the approaching survey vessel before the received levels 
reach 160 dB. Migrating bowheads are likely to do so, though summering 
bowheads, if encountered may not. For convenience, GXT refers to either 
eventuality as an ``exposure''. As a result, GXT's average and maximum 
estimates for bowhead whale exposures are 59 and 337, respectively 
(Table 2). The average and maximum estimates of the number of exposures 
of cetaceans are beluga (163 and 650) and gray whale (84 and 337). The 
seasonal breakdown of these numbers is shown in Tables 5 and 6 and 
totaled in Table 7 in the application and Table 2 in this document. 
Other cetacean species may occasionally occur near the seismic areas, 
but given their low estimated densities in the area, they are not 
likely to be exposed to SPLs of 160 dB or greater. With a population 
size estimated to be 10,545 bowheads, NMFS estimates that the maximum 
percentage of the population that will be exposed would be 
approximately 3 percent. For beluga whales and gray whales these 
numbers represent less than 5 percent of each population stock size. 
NMFS believes that this number of potential Level B harassment takes is 
small.
    The ringed seal is the most widespread and abundant pinniped in 
ice-covered arctic waters, but there is a great deal of annual 
variation in population size and distribution of these marine mammals. 
Ringed seals account for the vast majority of marine mammals expected 
to be encountered, and, therefore, exposed to airgun sounds with 
received levels [gteqt]160 dB re 1 microPa (rms) during the proposed 
seismic survey. Haley and Ireland (2006) reported that 20 percent of 
ringed seals remained on the ice when a seismic vessel passed. Because 
the SPL radii for this project are assumed to be larger than those 
found in the Haley and Ireland (2006) project, NMFS and GXT believe a 
larger percent of ringed seals within the 160-dB radii are likely to 
remain on the ice while the M/V Discoverer passes, and not subject to 
potential harassment. Therefore, GXT's estimates of numbers of ringed 
seals that might be exposed to sound levels 160 dB re 1 microPa (rms) 
were reduced by 50 percent to account for animals that are expected to 
be out of the water, and hence exposed to much lower levels of seismic 
sounds. The average (and maximum) estimate is that 3056 (max. 12,223) 
ringed seals out of a Beaufort/Chukchi Sea population of 245,048 seals 
might be exposed to seismic sounds with received levels >160 dB. NMFS 
believes that this number of potential Level B harassment takes (less 
than 4 percent of the population size of ringed seals is small.
    Two other species of pinnipeds are expected to be encountered 
during the proposed seismic survey. With Alaskan stock estimates of 
300-450,000 and 1000 respectively, the bearded seal has average and 
maximum exposure estimates of 1776 and 7104, and the spotted seal has 
average and maximum exposure estimates of 17 and 70, respectively. 
These exposure estimates are small numbers relative to their population 
sizes. Finally, the harbor seal is unlikely to be encountered so no 
exposure estimates have been made.

Effects of Seismic Survey Noise on Subsistence Uses

    GXT (2006) reports that marine mammals are legally hunted in 
Alaskan waters by coastal Alaska Natives; species hunted include 
bowhead and beluga whales; ringed, spotted, and bearded seals; 
walruses, and polar bears. The importance of each of the various 
species varies among the communities based largely on availability. 
Bowhead whales, belugas, and walruses are the marine mammal species 
primarily harvested during the time of the proposed seismic survey. 
There is little or no bowhead hunting by the community of Point Lay, so 
beluga and walrus hunting are of more importance there. Members of the 
Wainwright community do hunt bowhead whales in the spring, although 
bowhead whale hunting conditions there are often more difficult than 
elsewhere, and traditionally they do not hunt bowheads during seasons 
when GXT's seismic operation would occur. Depending on the level of 
success during the spring bowhead hunt, Wainwright residents may be 
very dependent on the presence of belugas in a nearby lagoon system 
during July and August. Barrow residents focus hunting efforts on 
bowhead whales during the spring and generally do not hunt beluga then. 
Barrow residents also hunt in the fall.
    Bowhead whale hunting is the key activity in the subsistence 
economies of Barrow and Wainwright. 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).
    Bowhead whales migrate around northern Alaska twice each year, 
during the spring and autumn, and are hunted in both seasons. Bowhead 
whales are hunted from Wainwright only during the spring migration and 
animals are not successfully harvested every year. The spring hunt 
there and 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. 
Fall migration into Alaskan waters is primarily during September and 
October. However, in recent years a small number of bowheads have been 
seen or heard offshore from the Prudhoe Bay region during the last week 
of August (Treacy, 1993; LGL and Greeneridge, 1996; Greene, 1997; 
Greene et al., 1999; Blackwell et al., 2004).
    The location of the fall subsistence hunt near Barrow depends on 
ice conditions and (in some years) industrial a