Takes of Marine Mammals Incidental to Specified Activities; Taking Marine Mammals Incidental to an Exploration Drilling Program in the Chukchi Sea, Alaska

DEPARTMENT OF COMMERCE

National Oceanic and Atmospheric Administration

RIN 0648-XA811

Takes of Marine Mammals Incidental to Specified Activities; Taking Marine Mammals Incidental to an Exploration Drilling Program in the Chukchi Sea, Alaska

AGENCY:

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

ACTION:

Notice; issuance of an incidental harassment authorization.

SUMMARY:

In accordance with the Marine Mammal Protection Act (MMPA) regulations, notification is hereby given that NMFS has issued an Incidental Harassment Authorization (IHA) to Shell Gulf of Mexico Inc. (Shell) to take marine mammals, by harassment, incidental to offshore exploration drilling on Outer Continental Shelf (OCS) leases in the Chukchi Sea, Alaska.

DATES:

Effective July 1, 2012, through October 31, 2012.

ADDRESSES:

A copy of the issued IHA, application with associated materials, and NMFS' Environmental Assessment (EA) and Finding of No Significant Impact (FONSI) may be obtained by writing to Tammy Adams, Acting Chief, Permits and Conservation Division, Office of Protected Resources, National Marine Fisheries Service, 1315 East-West Highway, Silver Spring, MD 20910, 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 also be viewed, by appointment, during regular business hours, at the aforementioned address.

FOR FURTHER INFORMATION CONTACT:

Candace Nachman, Office of Protected Resources, NMFS, (301) 427-8401.

SUPPLEMENTARY INFORMATION:

Background

Sections 101(a)(5)(A) and (D) of the MMPA (16 U.S.C. 1361

et seq.

) direct the Secretary of Commerce to allow, upon request, the incidental, but not intentional, taking of small numbers of marine mammals by U.S. citizens who engage in a specified activity (other than commercial fishing) within a specified geographical region if certain findings are made and either regulations are issued or, if the taking is limited to harassment, a notice of a proposed authorization is provided to the public for review.

Authorization for incidental takings shall be granted if NMFS finds that the taking will have a negligible impact on the species or stock(s), will not have an unmitigable adverse impact on the availability of the species or stock(s) for subsistence uses (where relevant), and if the permissible methods of taking and requirements pertaining to the mitigation, monitoring and reporting of such takings are set forth. NMFS has defined “negligible impact” in 50 CFR 216.103 as “* * * an impact resulting from the specified activity that cannot be reasonably expected to, and is not reasonably likely to, adversely affect the species or stock through effects on annual rates of recruitment or survival.”

Section 101(a)(5)(D) of the MMPA established an expedited process by which citizens of the U.S. can apply for an authorization to incidentally take small numbers of marine mammals by harassment. Section 101(a)(5)(D) establishes a 45-day time limit for NMFS review of an application followed by a 30-day public notice and comment period on any proposed authorizations for the incidental harassment of marine mammals. Within 45 days of the close of the comment period, NMFS must either issue or deny the authorization.

Except with respect to certain activities not pertinent here, the MMPA defines “harassment” as: “any act of pursuit, torment, or annoyance which (i) has the potential to injure a marine mammal or marine mammal stock in the wild [“Level A harassment”]; or (ii) has the potential to disturb a marine mammal or marine mammal stock in the wild by causing disruption of behavioral patterns, including, but not limited to, migration, breathing, nursing, breeding, feeding, or sheltering [“Level B harassment”].”

Summary of Request

NMFS received an application on June 30, 2011, from Shell for the taking, by harassment, of marine mammals incidental to offshore exploration drilling on OCS leases in the Chukchi Sea, Alaska. NMFS reviewed Shell's application and identified a number of issues requiring further clarification. After addressing comments from NMFS, Shell modified its application and submitted a revised application on September 12, 2011. NMFS carefully evaluated Shell's application, including their analyses, and deemed the application complete. The September 12, 2011, application is the one available for public comment (see

ADDRESSES

) and considered by NMFS for this IHA. NMFS published a Notice of Proposed IHA in the

Federal Register

on November 9, 2011 (76 FR 69958). That notice contained in depth descriptions and analyses that are generally not repeated in this document. Only in cases where descriptions or analyses changed is that information updated here. The most notable changes include: (1) Modifications to the aerial monitoring program presented in the marine mammal monitoring plan; and (2) updated information regarding Shell's Oil Spill Response Plan (OSRP).

Shell plans to drill up to three exploration wells at three possible drill sites and potentially a partial well at a fourth drill site on OCS leases offshore in the Chukchi Sea, Alaska, during the 2012 Arctic open-water season (July through October). Impacts to marine mammals may occur from noise produced by the drillship, zero-offset vertical seismic profile (ZVSP) surveys, and supporting vessels (including icebreakers) and aircraft. Shell requested authorization to take 13 marine mammal species by Level B harassment. However, the narwhal (

Monodon monoceros

) is not expected to be found in the activity area. Therefore, NMFS has authorized take of 12 marine mammal species, by Level B harassment, incidental to Shell's offshore exploration drilling in the Chukchi Sea. These species include: beluga whale (

Delphinapterus leucas

); bowhead whale (

Balaena mysticetus

); gray whale (

Eschrichtius robustus

); killer whale (

Orcinus orca

); minke whale (

Balaenoptera acutorostrata

); fin whale (

Balaenoptera physalus

); humpback whale (

Megaptera novaeangliae

); harbor porpoise (

Phocoena phocoena

); bearded seal (

Erignathus barbatus

); ringed seal (

Phoca hispida

); spotted seal (

P. largha

); and ribbon seal (

Histriophoca fasciata

).

Description of the Specified Activity and Specified Geographic Region

Shell plans to conduct an offshore exploration drilling program on U.S. Department of the Interior, Bureau of Ocean Energy Management (BOEM, formerly the Minerals Management Service) Alaska OCS leases located greater than 64 mi (103 km) from the Chukchi Sea coast during the 2012 open-water season. The leases were acquired during the Chukchi Sea Oil and Gas Lease Sale 193 held in February 2008. During the 2012 drilling program, Shell plans to drill up to three exploration wells at three drill sites and potentially a partial well at a fourth drill site at the prospect known as Burger. See Figure 1-1 in Shell's application for the lease block and drill site locations

(see

ADDRESSES

). All drilling is planned to be vertical.

The Notice of Proposed IHA (76 FR 69958, November 9, 2011) contained a full description of Shell's planned operations. That notice describes the equipment to be used for the different operational activities, the timeframe of activities, and the sound characteristics of the associated equipment. Except to clarify changes to the information contained in the proposed IHA notice, the information is not repeated here; therefore, please refer to the proposed IHA for the full description of the specified activity and specified geographic region.

Drilling Vessel

Shell intends to use the ice strengthened drillship

Discoverer

to drill the wells. The Notice of Proposed IHA (76 FR 69958, November 9, 2011) included the incorrect maximum anchor radius for the 8-point anchored mooring system. While on location at the Burger prospect drill sites, the maximum anchor radius is anticipated to be 2,609-2,904 ft (795-885 m).

Comments and Responses

A Notice of Proposed IHA published in the

Federal Register

on November 9, 2011 (76 FR 69958) for public comment. During the 30-day public comment period, NMFS received 10 comment letters from the following: the Alaska Eskimo Whaling Commission (AEWC); Inupiat Community of the Arctic Slope (ICAS); the Marine Mammal Commission (MMC); State of Alaska Department of Natural Resources; Consumer Energy Alliance; Resource Development Council; the North Slope Borough (NSB); BOEM; Shell; and Alaska Wilderness League (AWL), Audubon Alaska, Center for Biological Diversity, Defenders of Wildlife, Earthjustice, Natural Resources Defense Council, Northern Alaska Environmental Center, Ocean Conservancy, Oceana, Pacific Environment, Resisting Environmental Destruction on Indigenous Lands, Sierra Club, the Wilderness Society, and World Wildlife Fund (collectively “AWL”), along with an attached letter from David E. Bain, Ph.D.

AWL submitted several journal articles and documents as attachments to their comment letter. NMFS acknowledges receipt of these articles and documents but does not intend to address each one specifically in the responses to comments. All of the public comment letters received on the Notice of Proposed IHA (76 FR 69958, November 9, 2011) are available on the Internet at:

http://www.nmfs.noaa.gov/pr/permits/incidental.htm.

Following are the public comments and NMFS' responses.

General Comments

Comment 1:

Shell notes that the proposed IHA states that the IHA application was submitted by Shell Offshore Inc. when in fact it was submitted by Shell Gulf of Mexico Inc.

Response:

NMFS has corrected this error. It does not change any analyses.

Comment 2:

Shell notes that the proposed IHA contained the wrong anchor radius information for the

Discoverer

at the Burger prospect.

Response:

NMFS has updated that information in the description found earlier in this document. Because the radius is smaller than what was contained in the proposed IHA, it does not alter the analysis.

Comment 3:

Shell notes that the community of Point Hope is located approximately 206 mi (332 km) from the Burger prospect, not 180 mi (290 km) as indicated in the proposed IHA.

Response:

NMFS has updated that information in this notice. Because the distance is farther, it does not alter the analysis.

Comment 4:

The State of Alaska Department of Natural Resources, Consumer Energy Alliance, and Resource Development Council all urge NMFS to finalize Shell's IHA since NMFS has issued the proposed IHA.

Response:

After careful evaluation of all comments and the data and information available regarding potential impacts to marine mammals and their habitat and to the availability of marine mammals for subsistence uses, NMFS has issued the final authorization to Shell to take marine mammals incidental to conducting an exploration drilling program in the Chukchi Sea during the 2012 Arctic open-water season.

Comment 5:

ICAS incorporates the comments made by the AEWC into its letter by reference and urges NMFS to address the concerns of AEWC and its whaling captains.

Response:

All comments made by the AEWC are addressed in this document.

Comment 6:

The NSB stated in their letter that comments made previously on Shell's IHA applications for seismic and drilling are still applicable and are incorporated by reference into their letter dated December 9, 2011.

Response:

NMFS has responded to comments on Shell's seismic IHA requests in previous

Federal Register

notices. Those responses are incorporated into this document by reference (

e.g.

, 73 FR 66106, November 6, 2008; 74 FR 55368, October 27, 2009; 75 FR 49710, August 13, 2010). The NSB submitted letters regarding Shell's proposed Camden Bay exploration drilling programs for the years 2007, 2008, and 2010. Shell did not request (and NMFS did not propose to issue or issue) IHAs for exploratory drilling programs in the Chukchi Sea in 2007 and 2008. Shell did request an IHA (and NMFS published a Notice of Proposed IHA) for a 2010 exploratory drilling program in the Chukchi Sea. However, the NSB did not submit a letter regarding that program. NMFS has only provided responses to comments contained in the 2007, 2008, and 2010 letters that are different from comments in the NSB's 2011 letter on this IHA. Additionally, some of the comments in those three earlier letters are no longer relevant to Shell's program as currently proposed in this document.

MMPA Statutory Concerns

Comment 7:

The NSB states that the proposed IHA does not demonstrate that Shell's activities will take only a small number and have only a negligible impact on the species or stock. Additionally, the proposed IHA fails to distinguish between these two standards.

Response:

NMFS is required to authorize the take of “small numbers” of a species or stock if the taking by harassment will have a negligible impact on the affected species or stocks and will not have an unmitigable adverse impact on the availability of such species or stock for taking for subsistence purposes. See 16 U.S.C. 1371(a)(5)(D). In determining whether to authorize “small numbers” of a species or stock, NMFS determines that the taking will be small relative to the estimated population size and relevant to the behavior, physiology, and life history of the species or stock. With the exception of killer and minke whales, less than 1% of each species stock or population would be taken by Level B harassment incidental to Shell's activities. The modeling results indicate that only 1.2-1.85% of the minke whale population and 2.3% of the killer whale population would be taken by Level B harassment. NMFS is confident that takes resulting from Shell's activities will constitute only a “small number” of affected species or stocks for the following reasons:

(1) In all of the modeling submitted by Shell, a 1.5x correction factor was included;

(2) The estimated take levels do not mean that those numbers will

actually

be “taken” by Level B behavioral harassment. Some marine mammal species, such as bowheads, may engage

in avoidance behavior preventing their exposure to these levels of sound, and, even if exposed, may not exhibit a behavioral reaction; and

(3) The modeling results do not take into account the implementation of mitigation measures, which will lower the number of animals taken even further.

In making a negligible impact determination, NMFS considers a variety of factors, including: (1) The number of anticipated mortalities; (2) the number and nature of anticipated injuries; (3) the number, nature, intensity, and duration of Level B harassment; and (4) the context in which the takes occur. NMFS has determined that Shell's activities will not result in injury or mortality of marine mammals. The proposed IHA analyzed the number, nature, intensity, and duration of the Level B harassment that may occur and the context in which it may occur. That analysis led us to make a negligible impact finding.

Comment 8:

The AEWC and AWL state that NMFS cannot make a negligible impact determination without considering other activities planned for this year and future years in the U.S. Arctic Ocean and Russian and Canadian waters. AWL states that NMFS should also evaluate the potential impacts of future activities in both oceans and the acknowledged uncertainty regarding the effects of noise in the marine environment in the context of subsistence hunting.

Response:

NMFS considered the cumulative effects analysis contained in NMFS' Draft Environmental Impact Statement (EIS) on the “Effects of Oil and Gas Activities in the Arctic Ocean” (NMFS, 2011), NMFS' EA for the “Issuance of Incidental Harassment Authorizations for the Take of Marine Mammals by Harassment Incidental to Conducting Exploratory Drilling Programs in the U.S. Beaufort and Chukchi Seas,” and other relevant data to inform its MMPA determination here. Pursuant to the National Environmental Policy Act (NEPA), those documents contained a cumulative impacts assessment, as well as an assessment of the impacts of the proposed exploratory drilling program on marine mammals and other protected resources.

Section 101(a)(5)(D) of the MMPA and its implementing regulations require NMFS to consider a request for the taking of marine mammals incidental to

a specified activity

within a specified geographical region and, assuming certain findings can be made, to authorize the taking of small numbers of marine mammals while engaged in that activity. NMFS has defined “specified activity” in 50 CFR 216.103 as “any activity, other than commercial fishing, that takes place in a specified geographical region and potentially involves the taking of small numbers of marine mammals.” When making a negligible impact determination, NMFS considers the total impact during each 1-year period resulting from the specified activity only and supports its determination by relying on factors such as: (1) The number of anticipated mortalities from the activity; (2) the number and nature of anticipated injuries from the activity; (3) the number, nature, intensity, and duration of Level B harassment resulting from the activity; (4) the context in which the takes occur; (5) the status of the species or stock; (6) environmental features that may significantly increase the potential severity of impacts from the proposed action; (7) effects on habitat that could affect rates of recruitment or survival; and (8) how the mitigation measures are expected to reduce the number or severity of takes or the impacts to habitat. When making its finding that there will be no unmitigable adverse impact on the availability of the affected species or stock for taking for subsistence uses, NMFS analyzes the measures contained in the applicant's Plan of Cooperation (POC). Additionally, Shell signed the 2012 Conflict Avoidance Agreement (CAA) with the AEWC. NMFS included all necessary measures from both documents in the IHA to ensure no unmitigable adverse impacts to subsistence.

NMFS considered the impacts analyses (

i.e.,

direct, indirect, and cumulative) contained in the previously mentioned EIS and EA in reaching its conclusion that any marine mammals exposed to the sounds produced by the drillship, ice management/icebreaking vessels, support vessels and aircraft, and airguns would be disturbed for only a short period of time and would not be harmed or killed. Furthermore, the required mitigation and monitoring measures are expected to reduce the likelihood or severity of any impacts to marine mammals or their habitats over the course of the activities.

Moreover, NMFS gave careful consideration to a number of other issues and sources of information. In particular, NMFS relied upon a number of scientific reports, including the 2010 U.S. Alaska Marine Mammal Stock Assessment Reports (SARs) to support its findings. The SARs contain a description of each marine mammal stock, its geographic range, a minimum population estimate, current population trends, current and maximum net productivity rates, optimum sustainable population levels and allowable removal levels, and estimates of annual human-caused mortality and serious injury through interactions with commercial fisheries and subsistence harvest data. NMFS also used data from the annual and final Bowhead Whale Aerial Survey Program (BWASP) and Chukchi Offshore Monitoring in Drilling Area (COMIDA) reports.

After careful consideration of the proposed activities, the context in which Shell's proposed activities would occur, the best available scientific information, and all effects analyses (including cumulative effects), NMFS has determined that the specified activities: (1) Would not result in more than the behavioral harassment (

i.e.,

Level B harassment) of small numbers of marine mammal species or stocks; (2) the taking by harassment would not result in more than a negligible impact on affected species or stocks; and (3) the taking by harassment would not have an unmitigable adverse impact on the availability of such species or stocks for taking for subsistence uses. Therefore NMFS has decided to issue an IHA to Shell to take, by no more than Level B harassment, small numbers of marine mammals incidental to its Chukchi Sea exploratory drilling program.

Comment 9:

The MMC recommends that NMFS require Shell to evaluate the source levels of the

Discoverer

at the proposed drilling location and recalculate the 120-dB re 1 µPa harassment zone and estimated takes, as appropriate.

Response:

As conditioned in the IHA, Shell is required to conduct sound source verification and characterization of the equipment to be used, including the drilling rig. Shell is required to report received levels down to 120 dB re 1 µPa. Upon completion of those tests, Shell will then use the new sound radii for estimating take throughout the season. While new take estimates will not be calculated to replace those in the application, Shell will use the new radii for reporting estimated take levels in the 90-day report.

Comment 10:

The NSB and AWL state that NMFS must consider whether the increase in vessel presence and vessel noise around the drill sites and during transit across the Arctic have the potential to disturb marine mammals.

Response:

Shell's application and NMFS' Notice of Proposed IHA (76 FR 69958, November 9, 2011) outline all of the vessels intended for use to support the exploratory drilling program. While the application and proposed IHA do not include source levels or take estimates for those vessels, their

presence is considered and accounted for in several of the mitigation measures. For example, vessel speed and maneuvering conditions apply to all vessels, not just the drill ship and icebreakers. Therefore, while NMFS contemplated the use of all vessels during activities and has included mitigation measures during operation of these vessels to reduce potentially disturbing marine mammals in the vicinity, NMFS does not consider the transit or operation of these vessels to rise to a level that would result in take.

Comment 11:

The NSB (in its 2008 letter) and AWL state that a lack of adequate information precludes NMFS from complying with the MMPA standards. AWL states that NMFS should defer all oil and gas-related IHAs while the necessary information is gathered.

Response:

As required by the MMPA implementing regulations at 50 CFR 216.102(a), NMFS has used the best scientific information available in assessing potential impacts and whether the activity will have no more than a negligible impact on the affected marine mammal species or stock (see response to

Comment 7

). However, while NMFS agrees that there may be some uncertainty regarding behavior of animals that have been previously exposed to industrial sounds and how that may impact survival and reproduction, the best available information supports our findings.

Industrial activities have been occurring (at varying rates) in the U.S. Arctic Ocean for decades, and the available measurable indicators do not suggest that these activities are having long-term impacts. For example, bowhead whales continued to increase in abundance during periods of intense seismic activity in the Chukchi Sea in the 1980s (Raftery

et al.,

1995; Angliss and Outlaw, 2007), even without implementation of current mitigation requirements. Additionally, industry has been collecting data and conducting monitoring in the region for many years and will continue to do so under this IHA. Therefore, NMFS has determined that a negligible impact finding is rational.

Comment 12:

AWL and the NSB (in its 2008 letter) note that Shell's activities have the potential to result in serious injury. AWL also states that in the proposed IHA, NMFS conflated two different regulatory provisions governing the issuance of IHAs when it stated that for there to be the potential for serious injury or mortality an activity must be “reasonably expected or likely” to result in serious injury or mortality. AWL's letter states: “There is no indication that NMFS considered the dire consequences of a spill when determining whether the `potential' for serious harm exists * * * Applying the proper standard, NMFS cannot conclude that Shell may proceed with an IHA.”

Response:

As analyzed in the proposed IHA, NMFS has determined that Shell's activities are not likely to result in injury, serious injury, or mortality. The activities for which Shell is authorized to take marine mammals would most likely result in behavioral harassment. The mitigation and monitoring measures analyzed in the proposed IHA and required in the authorization are designed to ensure the least practicable impact on marine mammals and their habitat and the availability of marine mammals for subsistence uses.

AWL cites to NMFS' definition of “negligible impact” to argue that the agency has improperly conflated separate regulatory standards. “Negligible impact is 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” (50 CFR 216.103).

NMFS believes its decision-making should be informed by whether impacts are actually reasonably likely to occur. This principle is recognized in multiple contexts, and this does not represent the conflation of separate regulatory standards (in this instance, “negligible impact” and “potential to result in serious injury or mortality”). It is well recognized in the cases interpreting NEPA. For example see

Ground Zero Ctr. for Non-Violent Action

v.

United States Dept of the Navy,

383 F.3d 1082, 1090-91 (9th Cir. 2004) (concluding that where Navy had concluded that risk was extremely remote, “such remote possibilities do not in law require environmental evaluation.”) As explained later in this document, this interpretation reflects NMFS' longstanding practice of issuing IHAs in cases where the agency found that the potential for serious injury or mortality was “highly unlikely” (

See

73 FR 40512, 40514, July 15, 2008; 73 FR 45969, 45971, August 7, 2008; 73 FR 46774, 46778, August 11, 2008; 73 FR 66106, 66109, November 6, 2008; 74 FR 55368, 55371, October 27, 2009). Interpreting “potential” to include impacts with any probability of occurring (

i.e.,

speculative or extremely low probability events) would be administratively unworkable and inconsistent with Congressional intent. NMFS' proposed IHA considered the risks of an oil spill in its analysis and used that analysis to make the final determinations here.

Comment 13:

BOEM asks that NMFS clarify how Shell will avoid violating condition 3(b) in the IHA, which specifies that take of any species not listed in the IHA is prohibited and that such take “may result in the modification, suspension or revocation” of the IHA, given that Shell will be flying marine mammal monitoring flights below 1,500 ft (457 m) in areas where walrus or polar bears might be present.

Response:

NMFS only has the authority to prescribe IHA conditions on species for which it has jurisdiction. Both the walrus and the polar bear are managed by the U.S. Fish and Wildlife Service (USFWS). Therefore, condition 3(b) does not refer to those two species. Moreover, NMFS' requirement to conduct marine mammal monitoring aerial surveys does not preclude Shell from complying with more stringent restrictions and conditions imposed by other Federal agencies. NMFS' IHA states that flights cannot be flown below 1,500 ft (457 m) except in certain circumstances. The IHA does not require that the flights must be flown below 1,500 ft (457 m) in those circumstances.

Comment 14:

BOEM notes that the draft IHA does not provide limits of incidental take to species nor require Shell to not exceed those limits. BOEM recommends that NMFS clarify to what extent Shell would or should monitor/report their incidental take on a more regular basis so to not exceed a specified authorized incidental take prior to submission of the draft 90-day report.

Response:

Table 8 in the Notice of Proposed IHA (76 FR 69958, November 9, 2011) outlined the levels of proposed take. The final table of the authorized take levels is included as an attachment to the issued IHA. Additionally, the IHA also includes a condition requiring Shell to submit daily marine mammal observation logs to NMFS.

Marine Mammal Impact Concerns

Comment 15:

The MMC recommends that NMFS require Shell to collect all new and used drilling muds and cuttings and either reinject them or transport them to an Environmental Protection Agency licensed treatment/disposal site outside the Arctic. The NSB and AWL also note that Shell should be required to have a near zero discharge policy in the Chukchi Sea, similar to what Shell will employ in the Beaufort Sea, in order to ensure the least practicable impact to marine mammals, their habitat, and subsistence hunters.

Response:

Shell's collection of drilling mud and cuttings and certain other waste streams is a voluntary decision on the part of the company for its Beaufort Sea exploratory drilling program. Shell will not be conducting such a program in the Chukchi Sea, a practice that is consistent with both the current Arctic Oil and Gas Exploration General Permit and the draft General Permit being considered by the U.S. Environmental Protection Agency. The discharge of drilling related effluents has been extensively studied in both temperate and Arctic regions (Neff, 2010) and, when employing water based muds, is generally considered to be of slight environmental impact. The removal of muds, cuttings, and other effluent streams from exploration drilling requires additional vessels, which results in additional vessel traffic and related noise (which can in turn increase the potential for vessel-marine mammal interactions and vessel-related air emissions). Given the concerns raised with respect to the cumulative impacts of vessel traffic in the Arctic, the speculative benefits of waste stream removal do not warrant imposing such a requirement on Shell in the Chukchi Sea. Shell will, however, collect water and other samples in both seas before, during, and after the drilling programs in order to study sediment and water chemistry, the biotic community, deposition, and bioaccumulation. The collection of these samples will repeat evaluations at the localized drill sites that have been conducted as part of the Joint Industry Monitoring Program for several years. NMFS has determined that even without requiring such a measure, Shell's activities will have a negligible impact on marine mammal species or stocks and will not have an unmitigable adverse impact on the availability of marine mammals for taking for subsistence uses.

Comment 16:

AWL states that NMFS' uniform marine mammal harassment thresholds do not consider documented reactions of specific species in the Arctic to much lower received levels. The letter notes reactions of bowhead and gray whales to certain activities emitting impulse sounds below 160 dB and of beluga and bowhead whales and harbor porpoise reacting to other sound sources below 120 dB. The letter also states: “At a minimum, any final IHA cannot apply thresholds that fail to accurately capture potential marine mammal harassment, as required by the standards imposed by the MMPA.” Similarly, Dr. Bain notes marine mammal reactions, and especially those of beluga whales and harbor porpoises, to sounds below NMFS' 160 dB and 120 dB thresholds.

Response:

For continuous sounds, such as those produced by drilling operations and during icebreaking activities, NMFS uses a received level of 120-dB (rms) to indicate the onset of Level B harassment. For impulsive sounds, such as those produced by the airgun array during the ZVSP surveys, NMFS uses a received level of 160-dB (rms) to indicate the onset of Level B harassment. Therefore, while a level of 160-dB was used to estimate take for a portion of the operations that will only occur for a total of 10-56 hours, depending on how many wells are drilled, during the entire 4-month open-water season, a threshold of 120-dB was used to estimate potential takes for all species from the drilling operations and ice management/icebreaking activities.

While some published articles indicate that certain marine mammal species may avoid seismic airguns (an impulsive sound source) at levels below 160 dB, NMFS does not consider that these responses rise to the level of a take, as defined in the MMPA. While studies, such as Miller

et al.

(1999), have indicated that some bowhead whales may have started to deflect from their migratory path 21.7 mi (35 km) from the seismic source vessel, it should be pointed out that these minor course changes are during migration and have not been seen at other times of the year and during other activities. To show the contextual nature of this minor behavioral modification, recent monitoring studies of Canadian seismic operations indicate that feeding, non-migratory bowhead whales do not move away from a noise source at a sound pressure level (SPL) of 160 dB. Therefore, while bowheads may avoid an area of 12.4 mi (20 km) around a noise source, when that determination requires a post-survey computer analysis to find that bowheads have made a 1 or 2 degree course change, NMFS does not consider that deviation to rise to a level of a “take,” as the change in bearing is due to animals sensing the noise and avoiding passage through the ensonified area during their migration and should not be considered as being displaced from their habitat. 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 μPa).

Although it is possible that marine mammals could react to any sound levels detectable above the ambient noise level within the animals' respective frequency response range, this does not mean that such reaction would be considered a take. According to experts on marine mammal behavior, whether a particular stressor could potentially disrupt the migration, breathing, nursing, breeding, feeding, or sheltering, etc., of a marine mammal,

i.e.,

whether it would result in a take, is complex and context specific, and it depends on several variables in addition to the received level of the sound by the animals. These additional variables include: other source characteristics (such as frequency range, duty cycle, continuous vs. impulse vs. intermittent sounds, duration, moving vs. stationary sources, etc.); specific species, populations, and/or stocks; prior experience of the animals (naive vs. previously exposed); habituation or sensitization of the sound by the animals; and behavior context (whether the animal perceives the sound as predatory or simply annoyance), etc. (Southall

et al.

2007). The 120-dB and 160-dB acoustic criteria are generalized thresholds based on the available data that is intended to assist in the accurate assessment of take while acknowledging that sometimes animals will respond at received levels below that and sometimes they will not respond in a manner considered a take at received levels above 120 dB.

Comment 17:

AWL notes that there is a lack of information regarding bowhead aggregations and feeding in the area. “Given the lack of information, the proposed IHA should not simply assume that the `closest primary feeding ground' is near Point Barrow.” They state that there is evidence of bowheads frequenting the area around Point Franklin. Dr. Bain also states that excluding whales from feeding areas effectively reduces the carrying capacity, which in turn reduces the rate of population increase and is equivalent to removing individuals from the population; therefore, a shift in feeding locations would not be harmless.

Response:

Most bowhead whales will be in the Canadian Beaufort Sea when Shell begins operations in July. The fall westward migration begins in late August/early September through the Beaufort Sea and then into the Chukchi Sea. The Barrow area is commonly used as a feeding area during spring and fall, with a higher proportion of photographed individuals displaying evidence of feeding in fall rather than spring (Mocklin, 2009). A bowhead whale feeding “hotspot” (Okkonen

et al.,

2011) commonly forms on the western Beaufort Sea shelf off Point Barrow in late summer and fall. Favorable conditions concentrate euphausiids and copepods, and bowhead whales congregate to exploit the dense prey (Ashjian

et al.,

2010,

Moore

et al.,

2010; Okkonen

et al.,

2011). Bowheads will reach this feeding ground in the fall prior to entering the area ensonified by Shell's Chukchi Sea operations. Although Shell will be conducting a similar operation in the Camden Bay area of the Beaufort Sea, whales that begin their migration into U.S. waters earlier in the season, will avoid sounds from Shell's operations, as activities will cease in the Beaufort Sea on August 25 until the close of the fall hunts at Kaktovik and Cross Island.

The COMIDA 2008-2010 Final Report (Clarke

et al.,

2011) notes sightings of bowhead whales in the Chukchi Sea in all months that surveys were flown (June through November), except November. Sighting rates were highest in October; however, there were no specific areas where whales were concentrated each year (Clarke

et al.,

2011). All feeding was observed close to shore between Point Franklin and Barrow, Alaska, in June, July, and September of 2009 (Clarke

et al.,

2011), which is more than 65 mi (105 km) from Shell's Burger prospect. There were no observations of feeding in the areas near Shell's proposed drill sites.

Moreover, while some whales may avoid the area around Shell's drilling program because of the increased sound levels while operations are ongoing, there has also been evidence that some bowheads continued feeding in close proximity to seismic sources (

e.g.,

Richardson, 2004). The sounds produced by the drillship are of lower intensity than those produced by seismic airguns. Therefore, if animals remain in ensonified areas to feed, their feeding opportunity would not be missed, and they would be in areas where the sound levels are not high enough to cause injury (as discussed in greater detail later in this document). In accordance with NMFS' implementing regulations at 50 CFR 216.102(a), NMFS used the best available science to make the requisite findings for issuance of the IHA. That information indicates that there will not be concentrated feeding at the Burger prospect and that Shell's activities will not negatively affect bowhead feeding in the vicinity of Shell's proposed activities.

Comment 18:

Dr. Bain states that the increase in vessel traffic associated with Shell's project increases the risk of ship strike. AWL also notes that the risk of a vessel strike or the effects of a large oil spill could lead to serious injury. Additionally, missing information precludes full assessment of the effects of a large oil spill on bowheads may alter how NMFS assesses the potential for serious injury or death.

Response:

NMFS acknowledges that there is always some risk of a ship strike whenever a vessel transits the ocean. However, the IHA requires Shell to implement several mitigation measures applicable to vessel operation (

e.g.,

speed restrictions in the presence of marine mammals or in inclement weather, avoiding multiple changes in direction when within 300 yards [274 m] of whales) to reduce further the low probability of a ship strike.

Again, in accordance with NMFS implementing regulations, we used the best information available to assess potential impacts from an oil spill in the proposed IHA. NMFS' EA also assesses impacts from a large oil spill and incorporates information by reference from other recently released NEPA documents by BOEM regarding the potential for and impacts of a large oil spill on the marine environment. Also, please see the response to

Comment 12

regarding the “potential” impact from activities. NMFS determined that there is not a risk of serious injury or death to occur from Shell's

specified activity

and therefore issuance of an IHA under the MMPA is appropriate.

Comment 19:

AWL and Dr. Bain note that potential impacts on females and calves merit “special consideration,” as they will migrate through the Chukchi Sea during the fall migration. NMFS must examine whether bowhead cow/calf pairs will suffer from Shell's activities and whether that could result in a greater degree of harm that would warrant specific mitigation measures.

Response:

NMFS discussed potential impacts to bowhead whales, including cow/calf pairs in the Notice of Proposed IHA (76 FR 69958, November 9, 2011). In the section that discussed potential impacts to marine mammals from the specified activity, NMFS described data from studies that included observations and reactions (or lack thereof) of cow/calf pairs to different anthropogenic activities. Mitigation measures are required in the IHA during vessel transits (

e.g.,

speed restrictions, avoiding multiple changes in direction when within 300 yards [274 m] of whales) through the Chukchi Sea and from shore to the drill sites. These measures will ensure that potential impacts are reduced to the lowest level practicable. Moreover, Shell will not enter the Chukchi Sea prior to July 1, after the conclusion of the spring bowhead whale migration.

As noted earlier in this document, the fall migration westward through the Beaufort Sea and into the Chukchi Sea does not begin until late August/early September. Koski and Miller (2004) found that mother/calf bowhead pairs were the last to enter the U.S. Beaufort Sea during the fall migration (typically arriving in September and lasting into October). Therefore, if mother/calf pairs are not arriving in the central Beaufort Sea until later in the migration, they would not reach the Chukchi Sea lease sale area until later in the season. Therefore, it is likely that Shell's activities will be nearing completion, if not already completed for the season before the majority of the mother/calf pairs reach that area of the Chukchi Sea.

AWL cites to previous NMFS and BOEM documents, which include mitigation measures specifically applicable to bowhead cow/calf pairs. However, these pertained to seismic surveys or other programs in the Beaufort Sea. As has been noted elsewhere in this document and the proposed IHA, sounds produced during seismic surveys are different than those produced during drilling operations. It was determined that such measures were not necessary for these operations. Additionally, as has been noted for previous actions in the Chukchi Sea lease sale area, conducting such mitigation measures is impracticable for applicant implementation. Based on the fact that few cow/calf pairs are likely to occur within the 120-dB ensonified area of Shell's operations and the protection afforded by the already required mitigation measures, additional measures are not necessary to ensure the least practicable impact on bowhead cow/calf pairs.

Comment 20:

AWL states that NMFS must consider potential effects on beluga mothers and calves and must evaluate whether enough is known about beluga habitat use to accurately predict the degree of harm expected from Shell's operations. The proposed IHA's negligible impact assessment provides very little discussion of beluga whales. Moreover, the proposed IHA appears to rely on a population estimate for the Beaufort Sea stock rather than the significantly smaller Chukchi Sea stock even though both stocks are found in the Chukchi Sea during the fall. Dr. Bain also notes that work will be underway while belugas are nursing and caring for calves.

Response:

As noted in responses to earlier comments in this document, as required by the MMPA implementing regulations at 50 CFR 216.102(a), NMFS has used the best scientific information available in assessing potential impacts and whether the activity will have no more than a negligible impact on the affected marine mammal species or stock. While NMFS agrees that there may be some uncertainty regarding spatial and temporal habitat needs of

belugas, the best available information supports our findings.

While Shell's exploratory drilling program will overlap temporally with the beluga calving season, it will not overlap spatially. Tagging data from the 1990s indicates that belugas from the eastern Beaufort Sea stock will be in Canadian waters (

i.e.,

Mackenzie Delta and Amundsen Gulf) in the summer (July and August) and do not start migrating through the Beaufort Sea until September but do so far offshore (Richard

et al.,

2001; DFO, 2000). In the summer months, belugas from the eastern Chukchi Sea stock are typically found in Kasegaluk Lagoon and Kotzebue Sound (Suydam

et al.,

2001), locations that are approximately 100 mi (161 km) or more south of the Burger prospect. Shell will transit far offshore so as not to disturb the summer beluga hunts conducted in Kasegaluk Lagoon and therefore will avoid interactions with mothers and calves. Tagging data of belugas from this stock have also indicated that they travel far offshore in the Beaufort Sea to Canadian waters later in the summer (Suydam

et al.,

2001). Based on this information, it is unlikely that many beluga mother/calf pairs will pass within the 120-dB isopleths of Shell's Chukchi Sea exploratory drilling program. Mitigation and monitoring measures will ensure that impacts to any belugas that do occur in the vicinity of the program will be at the lowest level practicable.

Comment 21:

AWL states that NMFS must consider whether Shell's ice management efforts have the potential to seriously injure or kill ringed seals resting on pack ice.

Response:

NMFS considered the potential impacts of Shell's ice management efforts to ringed seals resting on pack ice in the Notice of Proposed IHA (76 FR 69958, November 9, 2011) in the section regarding anticipated effects on marine mammal habitat. AWL also references the MMS 2008 Draft EIS for the Beaufort Sea and Chukchi Sea Planning Areas Oil and Gas Lease Sales 209, 212, 217, and 221 (MMS, 2008), which includes a reference to Reeves (1998). Reeves (1998) noted that some ringed seals have been killed by icebreakers moving through fast-ice breeding areas. In the proposed IHA analysis, NMFS considered this information and noted that since Shell's use of the icebreakers would occur outside of the ringed seal breeding and pupping seasons in the Chukchi Sea, serious injury or mortality from use of the icebreakers would not occur.

Limited ice breaking might be needed to assist the fleet in accessing/exiting the project area if large amounts of ice pose a navigational hazard. Ice seals have variable responses to ice management activity. Alliston (1980, 1981) reported icebreaking activities did not adversely affect ringed seal abundance in the Northwest Territories and Labrador. Brueggeman

et al.

(1992) reported ringed seals and bearded seals diving into the water when an icebreaker was 0.58 mi (0.93 km) away. However, Kanik

et al.

(1980) reported that ringed seals remained on sea ice when an icebreaker was 0.62-1.24 mi (1-2 km) away.

The drill site is expected to be mostly ice-free during July, August, and September, and the need for ice management should be infrequent. The presence of an icebreaker is primarily a safety precaution to protect the drill ship from damage. Ice seals could be on isolated floes that may need to be managed for safety. Any ice seals on floes approaching the drill ship may be disturbed by ice management activities. Ringed seals on an ice floe are anticipated to enter the water before the icebreaker contacts the ice, remain in the water as the ice moves past the drill ship, and could reoccupy ice after it has moved safely past the drill ship. As was discussed in the proposed IHA, NMFS determined that this activity and these reactions would result in Level B harassment. NMFS did not determine that there was a potential for serious injury or morality to occur from Shell's ice management efforts.

Comment 22:

Dr. Bain states that noise exposure can lead to stress, which can impair the immune system and result in an increase in mortality from disease. He also notes that impairing the energy balance can slow growth, delay onset of sexual maturity, and increase the interval between successful births, all of which can cause a reduction in the number of animals recruited to the population.

Response:

While deflection may cause animals to expend extra energy, there is no evidence that deflecting around oil and gas exploration activities (or other anthropogenic activities) is causing a significant behavioral change that will adversely impact population growth. In fact, bowhead whales continued to increase in abundance during periods of intense seismic activity in the Chukchi Sea in the 1980s (Raftery

et al.,

1995; Allen and Angliss, 2011). Additionally, as mentioned in the response to

Comment 17,

all feeding was observed close to shore between Point Franklin and Barrow, Alaska, in June, July, and September of 2009 (Clarke

et al.,

2011), which is more than 65 mi (105 km) from Shell's Burger prospect. There were no observations of feeding in the areas near Shell's proposed drill sites. Regarding recruitment of calves to the population, the count of 121 calves during the 2001 census was the highest yet recorded and was likely caused by a combination of variable recruitment and the large population size (George

et al.,

2004). The calf count provides corroborating evidence for a healthy and increasing population. Based on this information, NMFS does not expect Shell's activities to impact annual rates of recruitment or survival within the Western Arctic bowhead stock.

Comment 23:

Dr. Bain states that hearing loss or masking from exposure to high levels of noise would impair bowhead whales' ability to hear vocalizations. He also states that hearing loss and masking would increase vulnerability to predation or ship strike, which in turn could increase mortality.

Response:

As noted in the proposed IHA, the source level of the

Discoverer

is lower than the thresholds used by NMFS for the onset of auditory injury. Shutdown and power-down measures are required in the IHA when the airguns are in use to help reduce further the extremely low likelihood of temporary threshold shift (a Level B harassment). As noted in the proposed IHA, masking effects are anticipated to be limited. Annual acoustic monitoring near BP's Northstar production facility during the fall bowhead migration westward through the Beaufort Sea has recorded thousands of calls each year (for examples, see Richardson

et al.,

2007; Aerts and Richardson, 2008). To compensate for and reduce masking, some mysticetes may alter the frequencies of their communication sounds (Richardson

et al.,

1995a; Parks

et al.,

2007). Additionally, if some individuals avoid the drilling area, impacts from masking will be even lower. There is no evidence to suggest that any masking would increase the likelihood of death.

Comment 24:

Dr. Bain states that even though the bowhead population increased in the face of industry activity in the 1990s, an increase in disturbance now (while it appears close to carrying capacity) could result in slowed growth or a loss of individuals.

Response:

Based on information provided in the responses to other comments in this section, NMFS does not agree that population growth would be slowed as a result of Shell's proposed activity or increase the numbers of individuals lost. There are no data indicating that the population cannot continue to grow (as it has for over a decade) in the face of such activities.

Shell's activities will occur in a small portion of the bowheads' range.

Comment 25:

Dr. Bain notes that masking of beluga whale echolocation signals by noise, and temporary and permanent threshold shifts will impair the ability of belugas to find food. This mechanism is in addition to impaired abilities to find food due to displacement from high quality feeding areas.

Response:

As noted in the proposed IHA, beluga whale echolocation signals have peak frequencies from 40-120 kHz, which are far above the frequency range of the sounds produced by the devices to be used by Shell during the Chukchi Sea exploratory drilling program. Therefore, those industrial sounds are not expected to interfere with echolocation. Additionally, the source level of the drillship is lower than the thresholds used by NMFS for the onset of auditory injury. Shutdown and power-down measures are required in the IHA when the airguns are in use to help reduce further the extremely low likelihood of temporary threshold shift (a Level B harassment). Lastly, there are no data indicating that the area surrounding Shell's Burger prospect is an important feeding area for beluga whales.

Acoustic Issues/Concerns

Comment 26:

The MMC states that it is not clear which specific source level was used to model the size of the corrected 120-dB re 1 μPa harassment zone for the

Discoverer,

as the reported source levels for the

Discoverer

ranged from 177-185 re 1 μPa at 1 m. It also is not clear how the source level measurements taken in the South China Sea were incorporated in the model to estimate the 120-dB re 1 μPa harassment zone in the Chukchi Sea.

Response:

The modeling analysis considered 1/3-octave band levels to account for frequency-dependent propagation effects that cannot adequately be characterized with broadband analysis. The 1/3-octave band source levels were obtained from dedicated measurements of the

Frontier Discover

(now

Noble Discoverer

) during drilling activities in the South China Sea. A plot showing these levels is provided in the response to

Comment 27,

and the corresponding broadband levels could be computed by summing those if required. The modeling approach applied by JASCO Applied Science was the MONM parabolic equation acoustic propagation model in each 1/3-octave band from 10 Hz to 2 kHz. The resulting received band levels were summed to compute the broadband received levels at many depths, distances and directions from the planned drillship location. Representative sound level threshold radii were determined by calculating the 95th percentile distance, over all azimuths, at which the maximum threshold over all depths was received. This approach considers that animals may sample multiple depths as they pass by the drilling operation.

Comment 27:

Dr. Bain notes that sound propagation efficiency depends on conditions and that the modeling used by Shell does not capture the most efficient mode of propagation. He also states that there is great uncertainty with source levels based on single measurement locations, as was done for the

Discoverer.

Response:

The concern raised here about variability of profiles is addressed in the response to

Comment 29

. With regard to the question on which source levels were used for modeling, this study considered 1/3-octave band source levels from the

Discoverer

drillship obtained during dedicated measurements performed in 2009 in the South China Sea (Austin and Warner, 2010). The specific levels are representative of the drilling operation since that activity will occur for the majority of time. The source levels used for the ice management vessel are from surrogate measurements of the

Maersk Rover

transiting at 25% power.

Comment 28:

Dr. Bain states that noise sources associated with thruster use may result in a significant increase in the ensonified area; however, it is unclear from the IHA application how often the thrusters would be used.

Response:

Shell does not intend to use thrusters as part of its standard operating procedure throughout the drilling season. The

Discoverer

will be anchored in place. The only time thrusters would be used would be in the unlikely event that the

Discoverer

is blown off location and the drillship needs to be repositioned.

Comment 29:

Dr. Bain states that the correction factor of 1.5 applied to the distance to the 120 dB contour is inadequate to conservatively account for the variability.

Response:

The concern raised here is that the sound speed profile used for acoustic modeling of drill rig noise may not account for changes to the salinity and temperature profile that could influence and create variability in sound propagation, and the resulting variability might lead to conditions in which model estimates would not be conservative. The location-specific sound speed profiles considered for this modeling study were obtained from the GDEM database for conditions in July and October. A modeling study (Johnston

et al.,

2009) investigated the difference in sound propagation for both months and showed longer-range sound propagation using the October profile. To be precautionary and to avoid underestimating the propagation, the modeling at the Burger prospect that was used for marine mammal effects assessment was conducted using the October profile (see Figure 2). Therefore, a correction factor of 1.5 is appropriate in this circumstance.

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Comment 30:

Dr. Bain notes that when multiple sources are involved, such as an ice management vessel and drillship, accurate characterization of the sound fields will be necessary to determine whether their sound fields overlap and whether marine mammals are likely to deflect around one or both sources. NMFS should perform a sensitivity analysis using a variety of propagation conditions.

Response:

NMFS agrees that a modeling sensitivity analysis would provide a measure of expected variability. However, the acoustic modeling study that was performed to estimate Shell's drilling noise effects on marine mammals relied on environmental parameters that were expected to lead to better sound propagation, thereby providing overestimates of the generated noise field. That study considered the combined noise emissions of a support vessel and the drillship, and it would be representative of drilling operations during the vast majority of time while active ice management was not in progress. To better define the true noise levels and variability, Shell designed a field measurement program that monitors actual drilling sounds at several distances and at multiple directions over the full duration of drilling of the first well at Shell's Burger prospect in the Chukchi Sea. This monitoring will continuously sample the temporal variability of noise propagation due to changing oceanographic conditions over approximately one month. NMFS determined that this approach will

provide a better sampling of variability than a modeling sensitivity study.

Unlike the eastern Beaufort Sea, where the fall bowhead migration tends to occur across a relatively narrow depth/distance-from-shore corridor and where feeding concentrations are sometimes apparent, tagged bowhead whales migrate across the Chukchi over a broad area with little indication of concentration aside from offshore Barrow and the Chukotka coast (Quakenbush

et al.,

2010). Because the 487 active leases in the Chukchi Sea contain only 2% of the total probable habitat used by bowheads in September and only 1% in both October and November, there are very limited indications of significant use of the few lease blocks involved in this exploration drilling program. As such, the number of potential exposures and deflections are expected to be both low in number and of limited biological consequence.

Marine Mammal Biology Concerns

Comment 31:

AWL states that the Bering Sea stock of harbor porpoise is based on “arbitrarily set geographic boundaries.” AWL and Dr. Bain both note that the stock size is likely smaller than what is currently estimated and that smaller stocks tend to be more vulnerable to harm from human activities.

Response:

Currently, there are insufficient samples to draw conclusions about stock structure of harbor porpoise within Alaska. While NMFS acknowledges that perhaps smaller stocks should be recognized in Alaska, the best available science indicates that take from Shell's activities will potentially impact only small numbers of harbor porpoise and will not have a negligible impact on the affected species or stock. Using the current estimated stock size of 48,215 individuals for the Bering Sea stock, only 0.03% is estimated to be taken by harassment. If the number should be 16,271 (as suggested by AWL), this would still represent less than 0.1% of the stock size. NMFS does not agree that just because a stock contains fewer individuals than originally estimated that it is far less able to tolerate takes than expected. Dr. Bain does not provide any scientific evidence for this statement.

Comment 32:

AWL and Dr. Bain note that gray whales use Hanna Shoal for feeding and that Shell's operations may block gray whales' access to this habitat or cause them to abandon their feeding. Additionally, they note that since its Endangered Species Act (ESA) delisting in 1994, numbers have declined.

Response:

The COMIDA 2008-2010 Final Report (Clarke

et al.,

2011) notes 504 sightings of 835 gray whales during that time period, which were seen in every month of surveys each of the 3 years (

i.e.,

June to November) between Wainwright and Barrow within 31 mi (50 km) of shore. Clarke

et al.

(2011) note that sightings were also scattered throughout the study area more than 31 mi (50 km) offshore. The relative lack of gray whale sightings (and mud plumes, which are indicative of the presence of feeding gray whales) offshore was markedly different from that documented during surveys conducted from 1982-1991, when gray whales were frequently seen on Hanna Shoal (Moore and Clarke, 1992 cited in Clarke

et al.,

2011). Gray whale sightings were most common in the survey blocks closer to shore in all months (Clarke

et al.,

2011). Based on this information, it appears that currently nearshore locations are being used more frequently than Hanna Shoal for feeding by gray whales. Shell's operations (which are located more than 65 mi [105 km] from shore) are not expected to block gray whales' access to feeding grounds closer to shore. Additionally, even though it might require a slight deflection or deviation from the migration path, gray whales wanting to access the Hanna Shoal area would be able to do during Shell's operations.

Since 1994, NMFS has continued to monitor the status of the population consistent with its responsibilities under the ESA and the MMPA. In 1999, a NMFS review of the status of the eastern North Pacific stock of gray whales recommended the continuation of this stock's classification as non-threatened (Rugh

et al.,

1999). Workshop participants determined the stock was not in danger of extinction, nor was it likely to become so in the foreseeable future.

In 2001, several organizations and individuals petitioned NMFS to re-list the eastern North Pacific gray whale population. NMFS concluded that there were several factors that may be affecting the gray whale population, but there was no information indicating that the population may be in danger of extinction or likely to become so in the foreseeable future. The population size of the Eastern North Pacific (ENP) gray whale stock has been increasing over the past several decades despite an unusual mortality event in 1999 and 2000. The estimated annual rate of increase, based on the unrevised abundance estimates between 1967 and 1988, is 3.3% with a standard error of 0.44% (Buckland

et al.,

1993); using the revised abundance time series from Laake

et al.

(2009) leads to an annual rate of increase for that same period of 3.2% with a standard error of 0.5% (Punt and Wade, 2010). Prior to the revised abundance estimates of Laake

et al.

(2009), Wade (2002) conducted an assessment of the ENP gray whale stock using survey data through 1995-96. Wade and Perryman (2002) updated the assessment in Wade (2002) to incorporate the abundance estimates from 1997-1998, 2000-2001, and 2001-2002, as well as calf production estimates from the northward migration (1994 to 2001), into a more complete analysis that further increased the precision of the results. All analyses concluded that the population was within the stock's optimum sustainable population level (

i.e.,

there was essentially zero probability that the population was below the stock's maximum net population level), and estimated the population in 2002 was between 71% and 102% of current carrying capacity. NMFS continues to monitor the abundance of the stock through the MMPA stock assessment process, especially as it approaches its carrying capacity. If new information suggests a reevaluation of the ENP gray whales' listing status is warranted, NMFS will complete the appropriate reviews.

Comment 33:

AWL states that any final IHA must analyze potential effects of all of Shell's operations on ribbon, ringed, spotted, and bearded seals and must do so considering the distinct habitats and life histories for each. AWL also notes that portions of the ringed and bearded seal populations are proposed for listing under the ESA and that those listings were prompted, in part, by the effects of climate change on ice seal habitat. The added stress of diminishing habitat should be considered in NMFS' analysis here.

Response:

NMFS has considered the potential effects of Shell's activities on all four ice seal species in the context of the distinct habitats and life histories for each. In the proposed IHA, NMFS acknowledged the importance of sea ice to various life functions, such as breeding, pupping, and resting. Several of these species perform these functions on sea ice outside of the project area. Shell's activities would occur at a time of year when the ice seal species found in the region are not molting, breeding, or pupping. Therefore, these important life functions would not be impacted by Shell's activities. NMFS' EA for this action considers the impacts of climate change on ice seals in the region.

Comment 34:

AWL notes the recent outbreak of skin lesions and sores among ringed seals. The letter states that

NMFS should consider the weakened state of the population as part of the analysis. They also note that some spotted and bearded seals have shown symptoms as well.

Response:

NMFS began receiving reports of the outbreak in summer 2011 and declared an unusual mortality event in December 2011. An investigative team was established, and testing has been underway. Testing has ruled out numerous bacteria and viruses known to affect marine mammals, including Phocine distemper, influenza, Leptospirosis, Calicivirus, orthopoxvirus, and poxvirus. Foreign animal diseases and some domestic animal diseases tested for and found negative include foot and mouth disease, VES, pan picornavirus, and Rickettsial agents. Last month, preliminary radiation testing results were announced which indicate radiation exposure is likely not a factor in the illness. Further quantitative radionuclide testing is occurring this spring. Results will be made publicly available as soon as the analyses are completed.

Reports from the NSB indicate that hunters during early winter observed many healthy bearded and ringed seals. The seals behaved normally: They were playful, curious but cautious, and maintained distance from boats. No lesions were observed on any seals. During December 2011 and January 2012, 20-30 adult ringed seals were harvested from leads in the sea ice in the NSB. Based on local reports, these seals had neither hair loss nor lesions. However, during late February 2012, a young ringed seal with nodular and eroded flipper lesions but no hair loss was harvested. Additionally, necropsy results of the internal organs were consistent with animals with this disease that continues to affect ice seals in the NSB and Bering Strait regions. Chukotka hunters did not report any sightings or harvest of sick and/or hairless seals in December 2011 and January 2012.

NMFS has considered this information as part of its analysis in making the final determinations for this IHA. The data available to date do not indicate that this has weakened the population. Moreover, Shell's activities are anticipated to take less than 1% of the population of all of the stocks of all three species noted by the commenter. The sound that will be produced by Shell's activities is of a low level. Therefore, even if the population were weakened from this outbreak it would not change our evaluation of the impacts of this activity at the population level.

Comment 35:

Dr. Bain states the population censuses for the eastern Chukchi Sea and Beaufort Sea stocks of belugas have not been conducted in the last 10 years and that population trends are unknown. No evidence of population growth was seen when censuses were still being conducted.

Response:

In accordance with NMFS' implementing regulations at 50 CFR 216.102(a), NMFS used the best available science to make the requisite findings for issuance of the IHA. That science indicates that only small numbers of belugas will be taken and that those incidental takings will have no more than a negligible impact on the affected beluga stocks and will not have an unmitigable adverse impact on the availability of those belugas for taking for subsistence uses.

Density and Take Estimate Concerns

Comment 36:

The AEWC, NSB, AWL, and Dr. Bain state that using a strict density approach to estimate take is unreasonable, as it does not account for the movement of animals through the drilling area during the time period over which the activities will occur. The NSB states that this approach likely results in take estimates that are biased low. The AEWC and Dr. Bain suggest that NMFS should draw a line across the ensonified area and estimate the number of marine mammals that would be expected to cross that line during Shell's activities.

Response:

During migration, there are clear changes in the density of animals that pass through a particular area of ocean, and “take” estimates attempt to consider this. In other situations, it is difficult to account for the movements of individuals within a relatively small area of ocean. Using densities provides the best estimate of animals though it assumes that animals are distributed evenly in the environment, which is not correct. This approach has, however, been used for most statistical approaches to dealing with animals in such situations, and NMFS has determined it is the appropriate and most robust approach in this case. In most cases, it overestimates the number of animals actually “taken” by the activities because it assumes no avoidance of the area by individuals.

Other approaches to estimate take were explored, mostly notably application of Quakenbush

et al.

(2010), which produced similar low estimates. Application of probability of occurrence within a specific portion of an area as large as the Chukchi Sea over a period of a month is not the equivalent of estimating occurrence distribution along a cross transect of a migration. Quakenbush

et al.

(2010) do indicate that use of the central Chukchi area by bowhead whales during the fall is low (2% of the total probability of occurrence in September and 1% of the total probability of total occurrence in both October and November). Because Shell's exploration drilling would occur in only three of the 487 active leases in the Chukchi Sea, take estimates do not differ appreciably from those based upon density. Unless data from Quakenbush

et al.

(2010) are reanalyzed across narrow bands of the migration corridor, using density estimates provides a reliable method for estimating take.

Comment 37:

The NSB and AWL note that the modeled 120-dB isopleths for the

Discoverer

are different in the Beaufort and Chukchi Seas (with the isopleth being slightly smaller in the Chukchi Sea). Additionally, they question if the 120-dB isopleth for the

Discoverer

is correct given its nearly identical source level to the

Kulluk

drill rig (proposed for use in the Beaufort Sea), for which sound propagates out to the 120-dB isopleth at a much farther distance. If the modeled propagation is incorrect for the

Discoverer,

then this would bias the take estimates low.

Response:

The primary reason for the difference in the distance of the 120-dB isopleths for the

Discoverer

in the Beaufort Sea vs. the Chukchi Sea is due to differences in the geoacoustic parameters for the two seas that were input to the model. Water depth, seabed density, and seabed sound speed are generally the most important parameters that influence sound propagation.

Differences in sound propagation from the two rigs are real and are caused by differences in the design of the two vessels. While the broadband source levels for the

Discoverer

and

Kulluk

may be similar, their spectral properties differ considerably. Acoustic modeling considers the source levels in 1/3-octave frequency bands. Figures 3 and 4 show the band levels for both drillships during drilling. Of key importance are the significantly lower levels of the

Discoverer

in the 50 to 500 Hz bands that propagate well in the relatively shallow waters of these drilling operations. While the

Discoverer

apparently has higher band levels below 50 Hz, this energy is more rapidly attenuated than higher frequency sound energy. This characteristic of sound propagation in shallow waters leads to predominantly mid-frequency sounds (50-500 Hz) dominating the acoustic field at distance from the drillships. A further consideration is that the

Kulluk

source levels are known to include contributions from support vessels, and much of the mid-high frequency band

energy in its source levels may not originate entirely from the drillship itself, as acknowledged by Greene (1987). The

Discoverer

source level measurements by Austin and Warner (2010) were made at closer distances and do not include significant contributions from other vessels. Additionally, the IHA requires Shell to conduct sound source verification and characterization tests on all equipment used.

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Comment 38:

AWL notes that any final IHA must assess exactly when Shell's ice management/icebreaking will occur and also consider the effects of both ice management vessels operating simultaneously but at some distance apart. Because the fall migration through the Chukchi Sea can last late into October, any ice management during the fall could affect a large number of whales.

Response:

Because it cannot be predicted with absolute certainty as to when ice may be present in the area that could pose a risk to drilling operations, it is difficult to state with absolute certainty when Shell's ice management/icebreaking will occur. Using data on Arctic sea ice presence from recent years, Shell estimated the most likely times that such activities would be required. Shell will also implement an Ice Management Plan (IMP) to ensure real-time ice and weather forecasting is conducted in order to identify conditions that might put operations at risk and will modify activities accordingly. The description of Shell's activities in the proposed IHA indicated that both ice management vessels could be operating simultaneously at different locations and was considered in the analysis.

Comment 39:

Dr. Bain states that density estimates for harbor porpoise may be low since Shell determined densities based on industry vessel-based counts.

Response:

No published densities or data on survey efforts or sightings were available for harbor porpoise, but estimates had been calculated from

industry survey data from 2006-2008, so those densities were used. The commenter is correct that the industry vessels did not conduct standard randomized line-transect surveys while operating (except for short periods in 2006). However, this information was considered the best scientific information available to determine a density estimate for harbor porpoise in the Chukchi Sea. NMFS reviewed the COMIDA 2008-2010 Final Report to see if newer data were available, but the report notes that harbor porpoise were not sighted (Clarke

et al.,

2011), likely due to their small size, making it difficult to positively identify them from the aircraft.

Subsistence Use Concerns

Comment 40:

The AEWC and ICAS state that they have expressed concerns about direct impacts to the subsistence hunts resulting from deflection of bowhead whales by vessel traffic and underwater noise, as well as from icebreaking and geophysical exploration. The letters note that concerns about direct and indirect threats to hunting arise from discharge and associated impacts on water quality, the risk of an oil spill, and the cumulative impacts from the sum of all commercial and industrial activities occurring in our waters. Under the MMPA, NMFS has an obligation to ensure that any proposed activities do not have an unmitigable adverse impact on our subsistence activities.

Response:

NMFS analyzed the potential impacts from the activities noted here in the proposed IHA and the EA. Potential impacts to the availability of marine mammals for subsistence uses were included in those analyses. Based on the mitigation measures contained in the IHA to ensure the availability of marine mammals for subsistence uses, NMFS determined that Shell's activities would not have an unmitigable adverse impact on the availability of marine mammal species or stocks for taking for subsistence uses. Additionally, Shell worked independently with the AEWC to develop and sign a CAA, which also includes measures to reduce impacts to bowhead whaling from their drilling operations and other activities.

Comment 41:

The AEWC states that whaling has resumed in Wainwright, Point Hope, and Point Lay and that these communities have been allocated a quota to use for the fall hunt. The AEWC asks that NMFS correct the information in the notice and carry forward this information into all future analyses. The letter also states that NMFS' “analysis should consider the specific timing and location of subsistence hunting for each community as compared to the specific timing and location of Shell's proposed operations.” Lastly, the AEWC states that NMFS did not include a preliminary finding regarding whether or not Shell's activities would have an unmitigable adverse impact on the fall hunt in the Chukchi villages and must publish this preliminary finding for comment.

Response:

NMFS used the updated information on fall hunting activities in the communities of Wainwright, Point Hope, and Point Lay in the Draft EA (NMFS, 2012) that was released for public comment and has also updated that information in this analysis and will use it in all future analyses. NMFS' analysis considered both location and timing of subsistence hunting activities, as well as location and timing of Shell's operations. Lastly, NMFS is not required to publish a preliminary finding regarding “no unmitigable adverse impact to the availability of marine mammals for subsistence uses” at the proposed IHA stage. The MMPA implementing regulations indicate that NMFS will publish any preliminary finding of “negligible impact” or “no unmitigable adverse impact” for public comment along with the proposed IHA if preliminary findings have been made at that time. 50 CFR 216.104(c). In this instance, at the proposed IHA stage NMFS was still evaluating the available information and believed it would be beneficial to review information and comments submitted by the public before making determinations regarding whether Shell's proposed action will have a negligible impact on the affected species or stocks of marine mammals and no unmitigable adverse impact on the availability of such species or stocks for taking for subsistence uses. Based on our review, we have made the requisite findings of small numbers, negligible impact, and no unmitigable adverse impact on the availability of the taking of marine mammals for subsistence uses.

Comment 42:

The AEWC expressed concern about potential impacts to the subsistence hunt in the Bering Sea communities from end of season transits. Because the proposed IHA noted that Shell's IHA expires on October 31, they believe that this is adequate, at this time, to prevent any conflicts with Bering Sea communities so long as Shell begins transit towards the Bering Strait on October 31. The AEWC requests that NMFS consider late season transits to Bering Sea communities in all future

Federal Register

notices regarding IHAs for oil and gas activities in the Arctic. Shell should have plans in place to communicate with those communities if, for whatever reason, its ships are delayed in the leaving the Chukchi Sea.

Response:

Shell signed the 2012 CAA with the AEWC on March 26, 2012. In the signed 2012 CAA, Shell agreed to establish Communication Centers in the Bering Sea communities and will conduct such communications in the manner laid out in the CAA. Shell's IHA is valid for drilling operations through October 31. Therefore, demobilization and transit out of the area must begin by that date. Information shared with NMFS from hunters on St. Lawrence Island in 2011 noted that the fall bowhead whale hunts typically occur the week of Thanksgiving. Shell will begin to demobilize and transit south towards Dutch Harbor beginning on October 31, and will avoid being in the area when hunters from Gambell and Savoonga (on St. Lawrence Island) are actively hunting bowhead whales.

Comment 43:

The AEWC states that they are concerned about the potential for cumulative impacts to subsistence activities if Shell transits vessels back and forth between the Chukchi Sea and Beaufort Sea drill sites. The AEWC asks that NMFS specify whether and to what extent vessel traffic between the two locations is predicted, what impact that may have on the hunt at Barrow, and whether this vessel traffic may combine with deflection from the Beaufort Sea drill sites to create a large impact on the bowhead migration.

Response:

Shell's Beaufort and Chukchi exploration drilling programs are designed and resourced to be independent and self sufficient. With the exception of the vessels that would be transiting for the purpose of supporting a spill response (in the unlikely event that one occurs), it is not expected that there will be regular transits of vessels related to Chukchi operations into, or out of, the Beaufort theater of operation.

BOEM included the following condition within its approval of Shell's Chukchi Exploration Plan: “If Shell transits to the Chukchi Sea from the Beaufort Sea during the fall bowhead whale migration and before or during Barrow's fall bowhead whale subsistence hunt, Shell shall meet with the appropriate whaling captains to coordinate vessel transit routes westward through the Beaufort Sea to prevent any deflection of the bowhead whale migration and any conflicts with Barrow's fall whaling season. Emergency operations will take precedence over this condition.”

This condition is consistent with existing commitments made by Shell to

consult with subsistence hunters prior to and during vessel transits and other operations. Vessel transit and communication with subsistence hunters are addressed in the signed 2012 CAA. Shell will fund the operation of communication centers in each of the coastal communities throughout the period of exploration activities in the Chukchi Sea. Vessels will report their position and projected transit route and schedule to these communication centers every 6 hours. Information provided to these communication centers will be available to AEWC and other subsistence co-management organizations and to subsistence hunters within the communities for the purpose of supporting the avoidance or reduction of conflicts between industry and subsistence activities. Shell will also operate a network of Subsistence Advisors within each of the coastal communities. The role of the Subsistence Advisors is to actively consult with local hunters on a daily basis, to be aware of typical patterns of subsistence resource movements and behavior and patterns of subsistence harvest, to inform Shell of any potential for conflicts, and to aid in the adaptive resolution of potential for conflicts. Based on the fact that vessel transit between the two programs would only occur in extreme and unlikely circumstances, it is not anticipated that there will be additional impacts beyond those analyzed here.

Comment 44:

The MMC states that negotiating and completing a CAA related to bowhead whales is useful but also prompts the question as to why such agreements are not being developed with subsistence hunters taking other species that might be affected by oil and gas operations. With that in mind, the MMC recommends that NMFS issue the requested IHA but also facilitate the development of CAAs that involve all potentially affected communities and co-management organizations and take into account all potential adverse effects on all marine mammal species taken for subsistence purposes including, but not limited to, bowhead whales.

Response:

The signing of a CAA is not a requirement to obtain an IHA. The CAA is a document that is negotiated between and signed by the industry participant, AEWC, and the Village Whaling Captains' Associations. NMFS has no role in the development or execution of this agreement. Although the contents of a CAA may inform NMFS' no unmitigable adverse impact determination for bowhead (and to some extent beluga) whales, the signing of it is not a requirement. Regulations promulgated pursuant to the 1986 MMPA amendments require that for an activity that will take place near a traditional Arctic hunting ground, or may affect the availability of marine mammals for subsistence uses, an applicant for MMPA authorization must either submit a POC or information that identifies the measures that have been taken to minimize adverse impacts on subsistence uses. Shell submitted a POC with its IHA application, which was available during the public comment period. Additionally, as indicated earlier in this document, Shell signed the 2012 CAA with the AEWC on March 26, 2012.

NMFS (or other Federal agencies) has no authority to require agreements between third parties, and NMFS would not be able to enforce the provisions of CAAs because the Federal government is not a party to the agreements. Regarding the CAA signed with the AEWC, NMFS has reviewed that document, as well as Shell's POC. The majority of the conditions are identical between the two documents. NMFS has also included measures from the 2012 CAA between Shell and the AEWC relevant to ensuring no unmitigable adverse impact on the availability of marine mammals for subsistence uses. NMFS has also determined that the measures in the POC related to species other than the bowhead whale are sufficient to ensure no unmitigable adverse impact on the availability of those species for subsistence uses.

In the recently released Draft EIS on the Effects of Oil and Gas Activities in the Arctic Ocean (NMFS, 2011), NMFS began to examine both the CAA and POC processes. There are strengths and weaknesses in how both processes are currently executed. NMFS is committed to working with the AEWC, Alaska Beluga Whale Committee, and Ice Seal Committee and other stakeholders to improve upon and combine these processes, as appropriate.

Comment 45:

The NSB appreciates Shell's effort to mitigate impacts to the bowhead hunt; however, Shell's proposed activities may adversely impact subsistence hunting of other species in the Chukchi Sea. Mitigation measures are needed to protect eastern Chukchi Sea belugas and beluga hunters. Restricting transit through the Chukchi Sea until the hunt is completed at Point Lay would be an effective measure. NMFS must also evaluate impacts to seals from the transit of vessels associated with Shell's planned activities and how that may impact seal hunts.

Response:

In the proposed IHA, NMFS evaluated potential impacts to subsistence hunts of all species in the project area. Ringed seals are typically hunted from October through June, which is outside the time frame of Shell's operations. Although spotted and bearded seal hunts may overlap temporally with Shell's operations, the hunting grounds are located much closer to shore than where Shell will operate. When Shell conducts supply vessel and other transits between shore and the drill sites, Shell is required to implement mitigation measures to avoid unmitigable adverse impacts to subsistence hunts, including using the Communication Centers to find out about the timing and location of active hunting.

NMFS understands the NSB's concerns regarding vessel transit and how that may affect hunts in the Chukchi Sea communities, especially the summer beluga hunt at Point Lay. Shell has committed to transiting offshore of the hunt and to communicating with Point Lay via the Communication Center regarding vessel transits to ensure that they remain outside of the hunting areas. These measures were part of Shell's POC and are included in the IHA. Therefore, NMFS has determined that there will not be an unmitigable adverse impact on the availability of beluga whales and ice seals for taking for subsistence uses.

Mitigation and Monitoring Concerns

Comment 46:

Shell states that the 1,500 ft (457 m) flight altitude restriction mitigation measure applies to all “non-marine mammal observation” flights, thus allowing for observer flights to fly lower as needed to afford the best possible marine mammal sightings and identifications.

Response:

NMFS concurs. The measure was written in two different ways in several parts of the proposed IHA. One way only exempted takeoffs, landings, and emergency situations from the 1,500 ft (457 m) altitude restriction, while in other parts of the document marine mammal monitoring flights were also exempted. NMFS has eliminated the discrepancy in the final IHA. The exemption now applies to takeoffs, landings, emergency situations, and marine mammal monitoring flights.

Comment 47:

The MMC recommends that NMFS require Shell to develop and employ a more effective means to monitor the entire corrected 120-dB re 1 μPa harassment zone for the presence and movements of all marine mammals and for estimating the actual number of takes, including aerial and acoustic surveys of the proposed drilling sites before, during, and after drilling operations. The NSB and AWL also

recommend that NMFS require Shell to fly aerial surveys in the area of the offshore drill sites.

Response:

Shell's original monitoring plan included an acoustic component to record both equipment sounds and marine mammal vocalizations. Since submitting that monitoring plan, Shell has modified it to include an offshore aerial component. Shell will conduct a photographic aerial survey in 2012, which will serve as a pilot study for future surveys that could use an Unmanned Aerial System to capture the imagery. The proposed photographic surveys in the Chukchi and Beaufort Seas would collect data that will allow direct comparisons of photographic techniques for data collection with data collected by human observers aboard the aircraft in the Beaufort Sea. Additional details on the photographic survey can be found in Shell's revised monitoring plan (see

ADDRESSES

).

While the 120-dB harassment zone from the drill rig will likely extend beyond what the observers can effectively see from the drill rig, Shell will place Protected Species Observers (PSOs) on all vessels used for the drilling operations. Many of these vessels will be located several kilometers from the drill rig, thus expanding the visual observation zone. Moreover, Shell will supplement its vessel-based operations with marine mammal aerial observations, thus expanding the visual observation zone. PSOs will be stationed on the vessels to observe from the best vantage points available and will be equipped with “Big-eyes” and other binoculars to aid in detection. Additionally, NMFS does not contend that PSOs will be able to see every marine mammal within the harassment zone. Using the vessel-based and aerial platforms to detect and count marine mammal sightings and then to use those observations in conjunction with sightings from other surveys such as COMIDA is reasonable for estimating maximum take.

Comment 48:

The MMC recommends that NMFS track and enforce Shell's implementation of mitigation and monitoring measures to ensure that they are executed as expected.

Response:

During Shell's operating season, NMFS will meet weekly with staff from BOEM, the Bureau of Safety and Environmental Enforcement (BSEE), and the USFWS to review and analyze proprietary operations reports, including PSO logs to ensure environmental and regulatory compliance. Additionally, BSEE will have inspectors on the drilling platform 24 hours a day/7 days a week.

Comment 49:

The NSB, MMC, and AWL state that NMFS should require Shell to make monitoring data available to the public. The NSB states that in addition to the monitoring data, locations and activities of drill rigs, icebreakers, and support vessels should also be made publicly available.

Response:

In accordance with an agreement between NOAA, Shell, ConocoPhillips, and Statoil, data from Shell sponsored science and monitoring efforts and from those that are jointly funded by the signatory parties will be made available to NOAA and to the public. The manner of release, format of released data, site(s) of data repository, and rights of data use are currently being addressed by a working group. Public access to these data is being addressed through this process and would not be enhanced by conditions imposed through the IHA.

Shell has committed to the support and operation of communication centers in Kaktovik, Nuiqsut, Barrow, Wainwright, Point Lay, Point Hope, Kivalina, Kotzebue, St. Lawrence Island, and Wales. As required by the CAA (which Shell signed on March 26, 2012), all Shell vessels operating in the Beaufort and Chukchi Sea will contact the nearest communication center every 6 hours and provide the following information:

(A) Vessel name, operator of vessel, charter or owner of vessel, and the project the vessel is working on;

(B) Vessel location, speed, and direction; and

(C) Plans for vessel movement between the time of the call and the time of the next call. The final call of the day will include a statement of the vessel's general area of expected operations for the following day, if known at that time.

The vessels will also contact the nearest communications center in the event that operations change significantly from those projected during the prior 6 hour reporting period. The communication centers will be generally open and available to the public and will provide a capability for direct communications between subsistence hunters and Shell vessels. Shell will operate these centers for the entire duration of operations in the Chukchi and Beaufort Seas, rather than limiting operations to the periods of the bowhead subsistence hunt.

Since 2010, NMFS has required operators in the Arctic to provide vessel tracks during the season as a part of the required 90 day report. Given that the potentially impacted public are provided with multiple avenues with which they can acquire vessel location and activity data, and that vessel tracks will be made available to the general public at the end of the season, there is no additional need for real-time public access to vessel location information. Further, given that there are current and legitimate concerns with respect to security of vessels, crew, and operations, public access to vessel locations and activities may not be in the best interest of safe marine operations.

Cumulative Impact Concerns

Comment 50:

The MMC noted that it is important to consider that some of the animals may already be in a compromised state as a result of climate disruption, stochastic variation in food resources, or variation in physiological state due to normal life history events (

e.g.,

molting or reproduction in pinnipeds).

Response:

In the Notice of Proposed IHA (76 FR 69958, November 9, 2011), NMFS considered others factors, including when pinnipeds and cetaceans conduct varying life history functions and whether or not those activities overlap in time and space with Shell's Chukchi Sea exploratory drilling program. Pupping and breeding for some ice seals do not occur in the Chukchi Sea. Pupping of ringed and bearded seals, which do build subnivean lairs in the Chukchi Sea, occurs outside of Shell's operating timeframe in the Chukchi Sea. Additionally, in the EA for this action, NMFS analyzed impacts of other activities and factors, such as climate disruption. Based on this information, NMFS determined that Shell's activities would have no more than a negligible impact on the affected marine mammal species or stocks.

Comment 51:

Dr. Bain states that cumulative effects are of concern and that the drilling in the Chukchi Sea cannot be considered separately from other planned activities, including similar activities by Shell in the Beaufort Sea, as well as work proposed by other companies. Further, if exploratory drilling results in future production, the cumulative effect of production in the core of the migration route needs to be considered.

Response:

NMFS analyzed the combination of both of Shell's proposed 2012 drilling programs in its EA, as well as other seismic exploration and vessel transportation in the Beaufort and Chukchi Seas. Additionally, NMFS' response to

Comment 8

explains how other factors were taken into consideration when analyzing this proposal under the MMPA. Because it is unknown if Shell will successfully find

oil during its exploratory drilling program, it is premature and speculative to discuss potential impacts from building a production facility in the Chukchi Sea. If Shell finds oil, it would be several years before construction of a production facility would begin. Additional environmental analyses would be required at that time.

ESA Statutory Concerns

Comment 52:

AWL and BOEM note that NMFS should consider ringed and bearded seals in the ESA section 7 consultation.

Response:

The Notice of Proposed IHA (76 FR 69958, November 9, 2011) for this action noted that NMFS would initiate ESA section 7 consultation for bowhead, humpback, and fin whales. However, NMFS has included ringed and bearded seals in the Biological Opinion prepared for this action, which analyzes effects to ESA-listed species, as well as species proposed for listing.

Comment 53:

AWL states that the conclusions reached in NMFS' 2008 and 2010 Biological Opinions for oil and gas activities in the Arctic regarding effects of oil spills must be reconsidered.

Response:

NMFS' Office of Protected Resources Permits and Conservation Division requested consultation under section 7 of the ESA with the NMFS Alaska Regional Office Endangered Species Division. A new Biological Opinion has been prepared for this IHA. In April, 2012, NMFS finished conducting its section 7 consultation and issued a Biological Opinion, and concluded that the issuance of the IHA associated with Shell's 2012 Chukchi Sea drilling program is not likely to jeopardize the continued existence of the endangered bowhead, humpback, and fin whale, the Arctic sub-species of ringed seal, or the Beringia distinct population segment of bearded seal. No critical habitat has been designated for these species, therefore none will be affected.

Comment 54:

BOEM recommends that NMFS consult with USFWS regarding the effects of the proposed action on resources under USFWS jurisdiction, including the compatibility of the joint industry research program that NMFS continues to require in IHAs with existing ESA section 7 consultation between BOEM and USFWS.

Response:

NMFS has determined that issuance of the IHA to Shell will not affect species under USFWS jurisdiction and that formal consultation is not required. However, NMFS strives to work closely with other Federal agencies and would welcome any specific suggestions from BOEM or USFWS on future IHAs that would help to achieve coordinated and complementary mitigation and monitoring measures.

NEPA Statutory Concerns

Comment 55:

The AEWC and NSB states that NMFS must include information regarding upcoming oil and gas activities planned for the Beaufort and Chukchi Seas in 2012 in U.S., Russian, and Canadian waters, as well as reasonably foreseeable future drilling activities. Both letters request that NMFS develop a method for assessing impacts from multiple drilling operations and to ascertain the significance of multiple exposures to underwater noise, ocean discharge, and air pollution and vessel traffic.

Response:

NMFS' EA contains information on upcoming activities in U.S., Russian, and Canadian waters for the 2012 season, as well as reasonably foreseeable future drilling activities in the project area. The EA qualitatively describes how marine mammals could be impacted from multiple activities in a given season and what the results of those exposures might be.

Comment 56:

NSB states that NMFS should be required to prepare an EIS, not an EA, to adequately consider the potentially significant impacts of the proposed IHAs, including the cumulative impacts of Shell's proposed activities.

Response:

NMFS' 2012 EA was prepared to evaluate whether significant environmental impacts may result from the issuance of IHAs to Shell for the take of marine mammals incidental to conducting exploratory drilling programs in the U.S. Beaufort and Chukchi Seas, which is an appropriate application of NEPA. After completing the EA, NMFS determined that there would not be significant impacts to the human environment and accordingly issued a FONSI. Therefore, an EIS is not needed for this action.

Comment 57:

The NSB states that NMFS should consider the cumulative impact of discharge and whether bioaccumulation of contaminants could have lethal or sub-lethal effects on bowhead whales and other marine mammals. NMFS should then synthesize that information into a health impact assessment looking at the overall combined effect to the health of the local residents.

Response:

As explained by the Council on Environmental Quality, an EA is a concise document and should not contain long descriptions or detailed data which the agency may have gathered. Rather, it should contain a brief discussion of the need for the proposal, alternatives to the proposal, the environmental impacts of the proposed action and alternatives, and a list of agencies and persons consulted. See NEPA's Forty Most Asked Questions, 46 FR 18026 (March 23, 1981); 40 CFR 1508.9(b). The EA prepared for this action contains a discussion of water quality, including contaminants, in sections 3.1.5.2 and 4.2.1.5 and incorporates additional material by reference. It also notes that contaminants have the potential to bioaccumulate in marine mammals, but that monitoring has shown that oil and gas developments in the Alaskan Beaufort Sea “are not contributing ecologically important amounts of petroleum hydrocarbons and metals to the near-shore marine food web of the area” (EA at 4.2.2.3). Given that the studies done so far have detected no bioaccumulation of contaminants as a result of oil and gas activity in the Beaufort Sea, it is only a remote and highly speculative possibility that discharges from Shell's exploration drilling program could contribute to cumulative impacts from contaminants that could ultimately result in health impacts to local residents. Agencies are not required to consider such remote or speculative impacts in an EA (see

Ground Zero Ctr. for Non-Violent Action

v.

United States Dept of the Navy,

383 F.3d 1082, 1090 (9th Cir. 2004)). However, NMFS acknowledges the importance of this issue to residents of the NSB, and has included a more extensive discussion of environmental contamination and its potential effects in the Draft EIS on Effects of Oil and Gas Activities in the Arctic Ocean (NMFS, 2011).

Comment 58:

AWL states that it would be illegal for NMFS to approve the IHA without completing the EIS that is in progress. NSB also states that it would be shortsighted to allow Shell to proceed on a 1-year IHA when the impacts could negatively affect arctic resources and preclude options that could be developed in the forthcoming EIS.

Response:

While the Final EIS is still being developed, NMFS conducted a thorough analysis of the affected environment and environmental consequences from exploratory drilling in the Arctic in 2012 and prepared an EA specific to the two exploratory drilling programs proposed to be conducted by Shell. The analysis contained in that EA warranted a FONSI.

The analysis contained in the Final EIS will apply more broadly to multiple Arctic oil and gas operations over a period of five years. NMFS' issuance of IHAs to Shell for the taking of several

species of marine mammals incidental to conducting its exploratory drilling operations in the Beaufort and Chukchi Seas in 2012, as analyzed in the EA, is not expected to significantly affect the quality of the human environment. Additionally, the EA contained a full analysis of cumulative impacts.

Comment 59:

BOEM requests that NMFS' EA fully evaluate the potential for the NMFS-required, periodic low-level aerial marine mammal surveys and vessel operations to impact marine and coastal resources within the Ledyard Bay Critical Habitat Unit (LBCHU) and adjacent areas. BOEM recommends that NMFS require observation reports to include the location and altitude of the aircraft at the time of each marine mammal observation and that NMFS require observations of marine and coastal birds using a systematic survey protocol during any NMFS-required vessel entries into the LBCHU, as well as requiring that these vessels not approach flocks of eiders and that vessel routing be the shortest distance within the LBCHU.

Response:

NMFS' EA analyzes the impacts of all aspects of Shell's activities on all relevant resources in the area. Shell and its representatives maintain frequent communication with the Federal Aviation Administration and USFWS during the period included in the Chukchi aerial surveys program. During this time all notices to aviators are noted and observed,

e.g.

notices related to avoidance of Pacific walrus haul outs. The aerial flights either avoid flying through these areas, or move to a higher altitude when in close proximity to concentrations of sensitive resources. The aircraft also implements mitigation measures, such as changing the flight path or altitude, when the observers on board detect concentrations of sensitive resources or the presence of subsistence hunters.

The altitude and position of the aircraft during survey and transit and from vessels during transit are available from the flight and vessel tracks. Flight altitudes of 1,000 ft (305 m) or greater are of limited value for identification and counting of marine birds. Aerial overflights routinely increase their altitude to 1500 ft (457 m) when flying over the Ledyard Bay area during surveys along the Chukchi Sea coast (rather than the 1000 ft [305 m] altitude flown in other parts of the survey) to avoid disturbance of waterfowl that might be in the area. Any required vessel entries to the LBCHU have included survey protocols to record concentrations of seabirds, particularly eiders and to avoid such areas if concentrations were noted. However, because the IHA is issued pursuant to the MMPA, NMFS does not have the authority to include measures related to non-marine mammal species.

Oil Spill Concerns

Comment 60:

The NSB and MMC state that Shell's application and NMFS' Notice of Proposed IHA (76 FR 68974, November 7, 2011) do not contain adequate information regarding effects of a major oil spill. The MMC notes that NMFS is too dismissive of the potential for a large oil spill. The NSB requests clarification on how NMFS considers the risk of an oil spill when issuing MMPA authorizations for exploratory drilling activities, and contends that NMFS must analyze the potential harm to marine mammals and subsistence activities. The NSB also states that Shell's application lacks any information about potential take resulting from a release of oil in any amount.

Response:

NMFS' Notice of Proposed IHA contained information regarding measures Shell has instituted to reduce the possibility of a major oil spill during its operations, as well as potential impacts on cetaceans and pinnipeds, their habitats, and subsistence activities (see 76 FR 69976-69980, 69984, 70004, November 7, 2011). NMFS' EA also contains an analysis of the potential effects of an oil spill on marine mammals, their habitats, and subsistence activities. Much of that analysis is incorporated by reference from other NEPA documents prepared for activities in the region. There is no information regarding potential take from a release of oil because an oil spill is not a component of the “specified activity.”

DOI's BOEM and BSEE are the agencies with expertise in assessing risks of an oil spill. In reviewing Shell's Chukchi Sea Exploration Plan and Regional OSRP, BOEM and BSEE determined that the risk was low and that Shell will implement adequate measures to minimize the risk. Shell's OSRP identifies the company's prevention procedures; estimates the potential discharges and describes the resources and steps that Shell would take to respond in the unlikely event of a spill; and addresses a range of spill volumes, ranging from small operational spills to the worst case discharge calculations required to account for the unlikely event of a blowout. Additionally, NOAA's Office of Response and Restoration reviewed Shell's OSRP and provided input to DOI requesting changes that should be made to the plan before it should be approved. Shell incorporated NOAA's suggested changes, which included updating the trajectory analysis and the worst case discharge scenario. Based on these revisions, NOAA Ocean Service's Office of Response and Restoration believes that Shell's plans to respond to an offshore oil spill in the U.S. Arctic Ocean are satisfactory, as described in a memorandum provided to NMFS by the Office of Response and Restoration. Lastly, in the unlikely event of an oil spill, Shell will conduct response activities in accordance with NOAA's Marine Mammal Oil Spill Response Guidelines.

Comment 61:

The MMC notes that the risk of an oil spill is not simply a function of its probability of occurrence; it also must take into account the consequences if such a spill occurs. Those consequences are, in part, a function of the spill's characteristics and the ability of the industry and government to mount an effective response. The MMC states: “The assertion that Shell would be able to respond adequately to any kind of major spill is simply unsupported by all the available evidence.” The MMC asserts that the OSRP is still inadequate for addressing a large oil spill in the Arctic.

Response:

As noted in the response to

Comment 60,

DOI approved Shell's OSRP on February 17, 2012. That approval came after an extensive review process, and changes were made to the plan based on comments from DOI, NOAA, and other Federal agencies. The plan calls for Shell to have several response assets near the drill sites for immediate response, while also having additional equipment available for quick delivery, if needed. DOI will also continue to provide oversight, with exercises, reviews, and inspections. NMFS' EA and recent BOEM NEPA analyses assess impacts to the environment from an oil spill.

Comment 62:

The MMC recommends that NMFS require Shell to cease drilling operations in mid- to late September to reduce the possibility of having to respond to a large oil spill in ice conditions. AWL also states that NMFS should consider restrictions on late-season drilling.

Response:

NMFS has not included such a measure in its IHA. In December 2011, BOEM conditionally approved Shell's Chukchi Sea Exploration Plan. One of the conditions of that approval is a measure designed to mitigate the risk of an end-of-season oil spill by requiring Shell to leave sufficient time to implement cap and containment operations as well as significant clean-up before the onset of sea ice, in the event of a loss of well control. Given current technology and weather

forecasting capabilities, Shell must cease drilling into zones capable of flowing liquid hydrocarbons 38 days before the first-date of ice encroachment over the drill site. In a press release issued by BOEM on December 16, 2011, the agency noted that based on a five-year analysis of historic weather patterns, BOEM anticipates November 1 as the earliest anticipated date of ice encroachment. The 38-day period would also provide a window for the drilling of a relief well, should one be required. However, Shell will be permitted to continue other operations, such as ZVSP surveys, after that date.

Comment 63:

The MMC recommends that NMFS require Shell to develop and implement a detailed, comprehensive and coordinated Wildlife Protection Plan that includes strategies and sufficient resources for minimizing contamination of sensitive marine mammal habitats and that provides a realistic description of the actions that Shell can take, if any, to respond to oiled or otherwise affected marine mammals. The plan should be developed in consultation with Alaska Native communities (including marine mammal co-management organizations), state and Federal resource agencies, and experienced non-governmental organizations.

Response:

As noted in the response to

Comment 60,

Shell will operate any needed oil spill response activities in accordance with NOAA's Marine Mammal Oil Spill Response Guidelines. These guidelines were released to the public as part of NMFS' Programmatic EIS on the Marine Mammal Health and Stranding Response Program and were available for public review at that time. Those guidelines also underwent legal and peer review before being released. Those guidelines are currently being updated based on lessons learned from the Deepwater Horizon spill in the Gulf of Mexico.

Proposed IHA Language Concerns

The comments and concerns contained in this grouping relate to the language that was contained in the Notice of Proposed IHA (76 FR 70004-70007, November 9, 2011) in the section titled “Proposed Incidental Harassment Authorization.” The commenters requested clarification or changes to some of the specific wording of the conditions that would be contained in the issued IHA. The referenced condition in the proposed IHA is noted in the comments here. Numbers of the conditions match the proposed IHA and may differ slightly from the issued IHA.

Comment 64:

Regarding Condition 1, Shell asks that the IHA become effective on July 1 instead of July 4 since the company will begin transiting into the Chukchi Sea on July 1 (but not before), if weather permits, and could therefore arrive on location at the Burger prospect before July 4.

Response:

NMFS has made the requested change. Changing the date from July 4 to July 1 does not alter any of the analyses contained in the proposed IHA.

Comment 65:

Regarding Condition 2, Shell asks that the language of the IHA not limit the incidental takings from authorized sound sources to those made while only on Shell lease holdings because ice management activities may occur beyond the lease boundaries and the continuous noise of the drillship may extend beyond the limits of Shell's lease holdings.

Response:

NMFS has retained the first sentence of Condition 2, as originally proposed, which states that only activities associated with Shell's 2012 Chukchi Sea exploration plan are covered by the IHA. Because the exploration plan describes the locations of activities, NMFS has determined that language is legally sufficient. NMFS understands, and did analyze, that ice management may at times occur 25 mi (40 km) from the actual drill site. Additionally, NMFS analyzed the propagation and sound isopleths of the drill rig, which may attenuate beyond the actual lease holding itself.

Comment 66:

Regarding Condition 3(a), Shell requests that narwhal be included in the list of species for which incidental take is authorized.

Response:

As noted in the Notice of Proposed IHA (76 FR 69958, November 9, 2011), NMFS determined that presence of narwhal in the U.S. Chukchi Sea is rare and extralimital. Encounters are unlikely.

Comment 67:

Regarding Condition 4, BOEM recommends that aircraft associated with the marine mammal surveys be included in the list of sound sources for which taking is authorized.

Response:

NMFS concurs and has added aircraft to the list of sound sources covered by the IHA.

Comment 68:

Regarding Condition 7(a), Shell asks whether the response they provided to NMFS on July 29, 2011, for a definition of “group” is consistent with the intent meant by NMFS in the

Federal Register

notice. As a general practice, Shell will adopt a definition of a group as being three or more whales observed within a 547-yd (500-m) area and displaying behaviors of directed or coordinated activity (

e.g.,

group feeding).

Response:

NMFS agrees with this definition and will add the following sentence to Condition 7(a): “For purposes of this Authorization, a group is defined as being three or more whales observed within a 547-yd (500-m) area and displaying behaviors of directed or coordinated activity (

e.g.,

group feeding).

Comment 69:

Shell requests that Condition 7(d) be modified to match with the language contained in Condition 9(f), which allows marine mammal monitoring flights to also fly below the 1,500-ft (457-m) altitude restriction. In the proposed IHA, those two conditions contradicted one another. BOEM also requested clarification of Condition 7(d).

Response:

NMFS agrees that Condition 7(d) should be rewritten to match Condition 9(f). The condition now reads as follows: “Aircraft shall not fly within 1,000-ft (305-m) of marine mammals or below 1,500-ft (457-m) altitude (except during marine mammal monitoring, takeoffs, landings, or in emergency situations) while over land or sea.”

Comment 70:

Regarding Condition 7(e), Shell asks if the length of daily duty restrictions included in the measure apply only to the drillship and ice management vessels or to all vessels, including smaller support vessels. Shell's view is that the remainder of support vessels, not included as “sound sources,” will have fewer observers than either the drillship or ice management vessels (mainly due to bunk space), which will be sufficient to cover marine mammal observations.

Response:

NMFS concurs that the watch requirements were meant to apply to the drillship and two ice management vessels. PSOs will be required to be stationed on the other support vessels. However, they will not need to be on watch 24 hours a day, as those vessels are not always active 24 hours a day. PSOs will need to be on watch when the smaller support vessels are active, such as for supply transport.

Comment 71:

BOEM recommends that Condition 7(f), or a new similar section focusing on aerial observations, require that marine mammal observation reports include the location and altitude of the aircraft at the time of each observation.

Response:

Aircraft altitude and location are available from the flight track logs. NMFS has added a requirement to include this information in the marine mammal sighting logs.

Comment 72:

Regarding Condition 7(f)(iv), Shell requests that the requirement to measure water temperature be removed as a stipulation under this measure given that it lacks material value to the recording of

marine observations and adherence to other more salient mitigation measures.

Response:

NMFS included the recording of water temperature along with other more salient data collection parameters in the proposed IHA because it was included in Shell's original monitoring plan. After further discussion with Shell, NMFS agrees that it is not necessary to record water temperature each time a marine mammal is sighted and has removed the requirement from the IHA.

Comment 73:

Regarding Condition 9(a), Shell notes that the condition should mention the Burger Prospect and not the Camden Bay drill sites. BOEM recommends that NMFS provide a definition of the polynya zone so that Shell can effectively comply with this condition.

Response:

NMFS has corrected the error and removed mention of the Camden Bay drill sites from the condition. NMFS does not have a definition of the polynya zone and does not believe it is necessary to include one in the IHA.

Comment 74:

Regarding Condition 10, BOEM recommends inclusion of a brief description of the 4MP and similar programs as a part of the proposed action.

Response:

NMFS has determined that such a description is unnecessary in the IHA, as it is described in this document and the associated Final EA.

Comment 75:

Regarding Condition 10(c)(i), as well as Condition 11(a), Shell requests that NMFS include language reflecting the flexibility of providing the drilling sounds on a “rolling” basis. Shell states that sound source verifications for the drilling vessel will necessitate that recordings of the various sounds of the drilling program continue throughout the drilling season. Hence, all drilling program sounds will not be available within 5 days of initiating drilling. Instead, Shell volunteers to provide to NMFS a “rolling” transmission of recorded drilling program sounds throughout the drilling program.

Response:

NMFS concurs that a “rolling” transmission of sound signatures is appropriate based on the fact that different activities will be conducted at various times throughout the open-water season. In order to capture all of the different sound signatures and for that data to be transmitted to NMFS, it is not appropriate to do it all in the first 5 days but rather to collect the data on a real-time basis. Spectrograms will be calculated daily, and all information will be included in a weekly report that discusses the drillship and vessel activities that occurred during the week. Language has been included in the IHA to reflect this weekly reporting requirement.

Comment 76:

Regarding Condition 10(c)(ii), Shell asks that the phrase “to the extent practical” precede the last sentence of the measure. Shell fully intends to deploy and execute the study as designed. However, conditional temporal and spatial factors, such as ice at the locations for deployment of acoustic recorders could cause some recorders to not be deployed or to be deployed at alternate locations.

Response:

NMFS has made the requested language change to the condition.

Comment 77:

Regarding Condition 11(d), Shell requests that the IHA stipulate that the comprehensive report be due 240 days from the end of the drilling season instead of 240 days from the date of issuance, since the IHA is being issued months before the start of the program.

Response:

NMFS agrees and has rewritten the condition to state that the comprehensive report is due 240 days from the date of expiration of the IHA (

i.e.,

240 days from October 31, 2012).

Description of Marine Mammals in the Area of the Specified Activity

The Chukchi Sea supports a diverse assemblage of marine mammals, including: Bowhead, gray, beluga, killer, minke, humpback, and fin whales; harbor porpoise; ringed, ribbon, spotted, and bearded seals; narwhals; polar bears (

Ursus maritimus

); and walruses (

Odobenus rosmarus divergens;

see Table 4-1 in Shell's application). The bowhead, humpback, and fin whales are listed as “endangered” under the ESA and as depleted under the MMPA. Certain stocks or populations of gray, beluga, and killer whales and spotted seals are listed as endangered or are proposed for listing under the ESA; however, none of those stocks or populations occur in the activity area. On December 10, 2010, NMFS published a notice of proposed threatened status for subspecies of the ringed seal (75 FR 77476) and a notice of proposed threatened and not warranted status for subspecies and distinct population segments of the bearded seal (75 FR 77496) in the

Federal Register

. Neither of these two ice seal species is considered depleted under the MMPA. Additionally, the ribbon seal is considered a “species of concern” under the ESA. Both the walrus and the polar bear are managed by the USFWS and are not considered further in this IHA notice.

Of these species, 12 are expected to occur in the area of Shell's operations. These species include: The bowhead, gray, humpback, minke, fin, killer, and beluga whales; harbor porpoise; and the ringed, spotted, bearded, and ribbon seals. Beluga, bowhead, and gray whales, harbor porpoise, and ringed, bearded, and spotted seals are anticipated to be encountered more than the other marine mammal species mentioned here. The marine mammal species that is likely to be encountered most widely (in space and time) throughout the period of the drilling program is the ringed seal. Encounters with bowhead and gray whales are expected to be limited to particular seasons. Additional information about species occurrence in the project area was provided in the Notice of Proposed IHA (76 FR 69958, November 9, 2011). Where available, Shell used density estimates from peer-reviewed literature in the application. In cases where density estimates were not readily available in the peer-reviewed literature, Shell used other methods to derive the estimates. NMFS reviewed the density estimate descriptions and articles from which estimates were derived and requested additional information to better explain the density estimates presented by Shell in its application. This additional information was included in the revised IHA application. The explanation for those derivations and the actual density estimates are described later in this document (see the “Estimated Take by Incidental Harassment” section).

Shell's application contains information on the status, distribution, seasonal distribution, abundance, and life history of each of the species under NMFS jurisdiction mentioned in this document. When reviewing the application, NMFS determined that the species descriptions provided by Shell correctly characterized the status, distribution, seasonal distribution, and abundance of each species. Please refer to the application for that information (see

ADDRESSES

). Additional information can also be found in the NMFS Stock Assessment Reports (SAR). The Alaska 2010 and 2011 Draft SARs are available at:

http://www.nmfs.noaa.gov/pr/pdfs/sars/ak2010.pdf

and

http://www.nmfs.noaa.gov/pr/pdfs/sars/ak2011_draft.pdf

, respectively.

Brief Background on Marine Mammal Hearing

When considering the influence of various kinds of sound on the marine environment, it is necessary to understand that different kinds of marine life are sensitive to different

frequencies of sound. Based on available behavioral data, audiograms have been derived using auditory evoked potentials, anatomical modeling, and other data. Southall

et al.

(2007) designate “functional hearing groups” for marine mammals and estimate the lower and upper frequencies of functional hearing of the groups. The functional groups and the associated frequencies are indicated below (though animals are less sensitive to sounds at the outer edge of their functional range and most sensitive to sounds of frequencies within a smaller range somewhere in the middle of their functional hearing range):

• Low frequency cetaceans (13 species of mysticetes): Functional hearing is estimated to occur between approximately 7 Hz and 22 kHz (however, a study by Au

et al.

(2006) of humpback whale songs indicate that the range may extend to at least 24 kHz);

• Mid-frequency cetaceans (32 species of dolphins, six species of larger toothed whales, and 19 species of beaked and bottlenose whales): Functional hearing is estimated to occur between approximately 150 Hz and 160 kHz;

• High frequency cetaceans (eight species of true porpoises, six species of river dolphins, Kogia, the franciscana, and four species of cephalorhynchids): Functional hearing is estimated to occur between approximately 200 Hz and 180 kHz; and

• Pinnipeds in Water: Functional hearing is estimated to occur between approximately 75 Hz and 75 kHz, with the greatest sensitivity between approximately 700 Hz and 20 kHz.

As mentioned previously in this document, 12 marine mammal species (four pinniped and eight cetacean species) are likely to occur in the exploratory drilling area. Of the eight cetacean species likely to occur in Shell's project area, five are classified as low frequency cetaceans (

i.e.,

bowhead, gray, humpback, minke, and fin whales), two are classified as mid-frequency cetaceans (

i.e.,

beluga and killer whales), and one is classified as a high-frequency cetacean (

i.e.,

harbor porpoise) (Southall

et al.,

2007). Additional information regarding marine mammal hearing and sound production is contained in the Notice of Proposed IHA (76 FR 69958, November 9, 2011).

Potential Effects of the Specified Activity on Marine Mammals

The likely or possible impacts of the exploratory drilling program in the Chukchi Sea on marine mammals could involve both non-acoustic and acoustic effects. Potential non-acoustic effects could result from the physical presence of the equipment and personnel. Petroleum development and associated activities introduce sound into the marine environment. Impacts to marine mammals are expected to primarily be acoustic in nature. Potential acoustic effects on marine mammals relate to sound produced by drilling activity, vessels, and aircraft, as well as the ZVSP airgun array. The potential effects of sound from the exploratory drilling program might include one or more of the following: Tolerance; masking of natural sounds; behavioral disturbance; non-auditory physical effects; and, at least in theory, temporary or permanent hearing impairment (Richardson

et al.,

1995a). However, for reasons discussed in the proposed IHA, it is unlikely that there would be any cases of temporary, or especially permanent, hearing impairment resulting from these activities.

In the “Potential Effects of the Specified Activity on Marine Mammals” section of the Notice of Proposed IHA (76 FR 69964-69976, November 9, 2011), NMFS included a qualitative discussion of the different ways that Shell's 2012 Chukchi Sea exploratory drilling program may potentially affect marine mammals. That discussion focused on information and data regarding potential acoustic and non-acoustic effects from drilling activities (

i.e.,

use of the drillship, icebreakers, and support vessels and aircraft) and use of airguns during ZVSP surveys. Marine mammals may experience masking and behavioral disturbance. The information contained in the “Potential Effects of Specified Activities on Marine Mammals” section from the proposed IHA has not changed. Please refer to the proposed IHA for the full discussion (76 FR 69958, November 9, 2011).

Exploratory Drilling Program and Potential for Oil Spill

As noted above, the specified activity involves the drilling of exploratory wells and associated activities in the Chukchi Sea during the 2012 open-water season. The impacts to marine mammals that are reasonably expected to occur will be acoustic in nature. In response to previous IHA applications submitted by Shell, various entities have asserted that NMFS cannot authorize the take of marine mammals incidental to exploratory drilling under an IHA. Instead, they contend that incidental take can be allowed only with a letter of authorization (LOA) issued under five-year regulations because of the potential that an oil spill will cause serious injury or mortality.

There are two avenues for authorizing incidental take of marine mammals under the MMPA. NMFS may, depending on the nature of the anticipated take, authorize the take of marine mammals incidental to a specified activity through regulations and LOAs or annual IHAs.

See

16 U.S.C. 1371(a)(5)(A) and (D). In general, regulations (accompanied by LOAs) may be issued for any type of take (

e.g.,

Level B harassment (behavioral disturbance), Level A harassment (injury), serious injury, or mortality), whereas IHAs are limited to activities that result only in harassment (

e.g.,

behavioral disturbance or injury). Following the 1994 MMPA Amendments, NMFS promulgated implementing regulations governing the issuance of IHAs in Arctic waters. See 60 FR 28379 (May 31, 1995) and 61 FR 15884 (April 10, 1996). NMFS stated in the preamble of the proposed rulemaking that the scope of IHAs would be limited to “ * * * those authorizations for harassment involving incidental harassment that may involve

non-serious injury.”

See 60 FR 28380 (May 31, 1995; emphasis added); 50 CFR 216.107(a). (“[e]xcept for activities that have the potential to result in serious injury or mortality, which must be authorized under 216.105, incidental harassment authorizations may be issued, * * * to allowed activities that may result in only the incidental harassment of a small number of marine mammals.”) NMFS explained further that applications would be reviewed to determine whether the activity would result in more than harassment, and, if so, the agency would either (1) attempt to negate the potential for serious injury through mitigation requirements, or (2) deny the incidental harassment authorization and require the applicant to apply for incidental take regulations. See id. at 28380-81.

NMFS' determination of whether the type of incidental take authorization requested is appropriate occurs shortly after the applicant submits an application for an incidental take authorization. The agency evaluates the proposed action and all information contained in the application to determine whether it is adequate and complete and whether the type of taking requested is appropriate. See 50 CFR 216.104; see also 60 FR 28380 (May 31, 1995). Among other things, NMFS considers the specific activity or class of activities that can reasonably be

expected

to result in incidental take; the

type

of incidental take authorization that is being requested; and the

anticipated

impact of the activity upon

the species or stock and its habitat. See

id.

at 216.104(a). (emphasis added). Any application that is determined to be incomplete or inappropriate for the type of taking requested will be returned to the applicant with an explanation of why the application is being returned. See id. Finally, NMFS evaluates the best available science to determine whether a proposed activity is reasonably expected or likely to result in serious injury or mortality.

NMFS evaluated Shell's incidental take application for its proposed 2012 drilling activities in light of the foregoing criteria and has concluded that Shell's request for an IHA is warranted. Shell submitted information with its IHA Application indicating that an oil spill is a highly unlikely event that is not reasonably expected to occur during the course of exploration drilling or ZVSP surveys.

See

Chukchi Sea IHA Application, pp. 3 and Attachment E—Analysis of the Probability of an “Unspecified Activity” and Its Impacts: Oil Spill. In addition, Shell's 2012 Exploration Plan indicates there is a “very low likelihood of a large oil spill event.” See Shell Offshore, Inc.'s Revised Outer Continental Shelf Lease Exploration Plan, Chukchi Sea, Alaska (May 2011), at p. 8-1; see also, Appendix F to Shell's Revised Outer Continental Shelf Lease Exploration Plan, at p. 4-174.

The likelihood of a large or very large (i.e., ≥1,000 barrels or ≥150,000 barrels, respectively) oil spill occurring during Shell's proposed program has been estimated to be low. A total of 35 exploration wells have been drilled between 1982 and 2003 in the Chukchi and Beaufort seas, and there have been no blowouts. In addition, no blowouts have occurred from the approximately 98 exploration wells drilled within the Alaskan OCS (MMS, 2007a). Attachment E in Shell's IHA Application contains information regarding the probability of an oil spill occurring during the proposed program and the potential impacts should one occur. Based on modeling conducted by Bercha (2008), the predicted frequency of an exploration well oil spill in waters similar to those in the Chukchi Sea, Alaska, is 0.000612 per well for a blowout sized between 10,000 barrels (bbl) to 149,000 bbl and 0.000354 per well for a blowout greater than 150,000 bbl. Please refer to Shell's application for additional information on the model and predicted frequencies (see

ADDRESSES

).

Shell has implemented several design standards and practices to reduce the already low probability of an oil spill occurring as part of its operations. The wells proposed to be drilled in the Arctic are exploratory and will not be converted to production wells; thus, production casing will not be installed, and the well will be permanently plugged and abandoned once exploration drilling is complete. Shell has also developed and will implement the following plans and protocols: Shell's Critical Operations Curtailment Plan; IMP; Well Control Plan; and Fuel Transfer Plan. Many of these safety measures are required by the Department of the Interior's interim final rule implementing certain measures to improve the safety of oil and gas exploration and development on the Outer Continental Shelf in light of the Deepwater Horizon event (see 75 FR 63346, October 14, 2010). Operationally, Shell has committed to the following to help prevent an oil spill from occurring in the Chukchi Sea:

• Shell's Blow Out Preventer (BOP) was inspected and tested by an independent third party specialist;

• Further inspection and testing of the BOP have been performed to ensure the reliability of the BOP and that all functions will be performed as necessary, including shearing the drill pipe;

• Subsea BOP hydrostatic tests will be increased from once every 14 days to once every 7 days;

• A second set of blind/shear rams will be installed in the BOP stack;

• Full string casings will typically not be installed through high pressure zones;

• Liners will be installed and cemented, which allows for installation of a liner top packer;

• Testing of liners prior to installing a tieback string of casing back to the wellhead;

• Utilizing a two-barrier policy; and

• Testing of all casing hangers to ensure that they have two independent, validated barriers at all times.

NMFS has considered Shell's proposed action and has concluded that there is no reasonable likelihood of serious injury or mortality from the 2012 Chukchi Sea exploration drilling program. NMFS has consistently interpreted the term “potential,” as used in 50 CFR 216.107(a), to only include impacts that have more than a discountable probability of occurring, that is, impacts must be reasonably expected to occur. Hence, NMFS has regularly issued IHAs in cases where it found that the potential for serious injury or mortality was “highly unlikely” (

See

73 FR 40512, 40514, July 15, 2008; 73 FR 45969, 45971, August 7, 2008; 73 FR 46774, 46778, August 11, 2008; 73 FR 66106, 66109, November 6, 2008; 74 FR 55368, 55371, October 27, 2009).

Interpreting “potential” to include impacts with any probability of occurring (

i.e.,

speculative or extremely low probability events) would nearly preclude the issuance of IHAs in every instance. For example, NMFS would be unable to issue an IHA whenever vessels were involved in the marine activity since there is always some, albeit remote, possibility that a vessel could strike and seriously injure or kill a marine mammal. This would also be inconsistent with the dual-permitting scheme Congress created and undesirable from a policy perspective, as limited agency resources would be used to issue regulations that provide no additional benefit to marine mammals beyond what can be achieved with an IHA.

Despite concluding that the risk of serious injury or mortality from an oil spill in this case is extremely remote, NMFS nonetheless evaluated the potential effects of an oil spill on marine mammals. While an oil spill is not a component of Shell's specified activity, potential impacts on marine mammals from an oil spill are discussed in more detail in the Notice of Proposed IHA (76 FR 69958, November 9, 2011) and NMFS' EA. Please refer to those documents for the discussion.

Anticipated Effects on Marine Mammal Habitat

The primary potential impacts to marine mammals and other marine species are associated with elevated sound levels produced by the exploratory drilling program (

i.e.

the drillship and the airguns). However, other potential impacts are also possible to the surrounding habitat from physical disturbance and an oil spill (should one occur). The proposed IHA contains a full discussion of the potential impacts to marine mammal habitat and prey species in the project area. No changes have been made to that discussion. Please refer to the proposed IHA for the full discussion of potential impacts to marine mammal habitat (76 FR 69958, November 9, 2011). NMFS has determined that Shell's exploratory drilling program is not expected to have any habitat-related effects that could cause significant or long-term consequences for marine mammals or on the food sources that they utilize.

Mitigation

In order to issue an incidental take authorization (ITA) under Sections 101(a)(5)(A) and (D) of the MMPA, NMFS must, where applicable, set forth the permissible methods of taking

pursuant to such activity, and other means of effecting the least practicable impact on such species or stock and its habitat, paying particular attention to rookeries, mating grounds, and areas of similar significance, and on the availability of such species or stock for taking for certain subsistence uses (where relevant). This section summarizes the contents of Shell's Marine Mammal Monitoring and Mitigation Plan (4MP).

Operational Mitigation Measures

Shell submitted a 4MP as part of its application (Attachment C; see

ADDRESSES

). Shell submitted a revised 4MP after they made voluntary changes to the plan and after the plan was reviewed by an independent peer review panel (see the “

Monitoring Plan Peer Review”

section for additional details). The revised plan is also available to the public (see

ADDRESSES

). The planned offshore drilling program incorporates both design features and operational procedures for minimizing potential impacts on marine mammals and on subsistence hunts. The design features and operational procedures have been described in the IHA and LOA applications submitted to NMFS and USFWS, respectively, and are summarized here. Survey design features include:

• Timing and locating drilling and support activities to avoid interference with the annual subsistence hunts by the peoples of the Chukchi villages;

• Identifying transit routes and timing to avoid other subsistence use areas and communicating with coastal communities before operating in or passing through these areas; and

• Conducting pre-season sound propagation modeling to establish the appropriate exclusion and behavioral radii.

Shell indicates, and we agree, that the potential disturbance of marine mammals during operations will be minimized further through the implementation of several ship-based mitigation measures, which include establishing and monitoring safety and disturbance zones.

Exclusion radii for marine mammals around sound sources are customarily defined as the distances within which received sound levels are greater than or equal to 180 dB re 1 µPa (rms) for cetaceans and greater than or equal to 190 dB re 1 µPa (rms) for pinnipeds. These exclusion criteria are based on an assumption that sounds at lower received levels will not injure these animals or impair their hearing abilities, but that higher received levels might have such effects. It should be understood that marine mammals inside these exclusion zones will not necessarily be injured, as the received sound thresholds which determine these zones were established prior to the current understanding that significantly higher levels of sound would be required before injury would likely occur (see Southall

et al.,

2007). With respect to Level B harassment, NMFS' practice has been to apply the 120 dB re 1 µPa (rms) received level threshold for underwater continuous sound levels and the 160 dB re 1 µPa (rms) received level threshold for underwater impulsive sound levels.

Shell will monitor the various radii in order to implement necessary mitigation measures. Initial radii for the sound levels produced by the

Discoverer,

the icebreaker, and the airguns have been modeled. Measurements taken by Austin and Warner (2010) indicated broadband source levels between 177 and 185 dB re 1 µPa rms for the

Discoverer.

Measurements of the icebreaking supply ship

Robert Lemeur

pushing and breaking ice during exploration drilling operations in the Beaufort Sea in 1986 resulted in an estimated broadband source level of 193 dB re 1 µPa rms (Greene, 1987a; Richardson

et al.,

1995a). Based on a similar airgun array used in the shallow waters of the Beaufort Sea in 2008 by BP, the source level of the airgun is predicted to be 241.4 dB re 1 µPa rms. Once on location in the Chukchi Sea, Shell will conduct SSV tests to establish safety zones for the previously mentioned sound level criteria. The objectives of the SSV tests are: (1) to quantify the absolute sound levels produced by drilling and to monitor their variations with time, distance, and direction from the drillship; and (2) to measure the sound levels produced by vessels operating in support of drilling operations, which include crew change vessels, tugs, ice management vessels, and spill response vessels. The methodology for conducting the SSV tests is fully described in Shell's 4MP (see

ADDRESSES

). Please refer to that document for further details. Upon completion of the SSV tests, the new radii will be established and monitored, and mitigation measures will be implemented in accordance with Shell's 4MP.

Based on the best available scientific literature, the source levels noted above for exploration drilling are not high enough to cause a temporary reduction in hearing sensitivity or permanent hearing damage to marine mammals. Consequently, Shell believes that mitigation as described for seismic activities including ramp ups, power downs, and shutdowns should not be necessary for drilling activities. NMFS has also determined that these types of mitigation measures, traditionally required for seismic survey operations, are not practical or necessary for this proposed drilling activity. Seismic airgun arrays can be turned on slowly (

i.e.,

only turning on one or some guns at a time) and powered down quickly. The types of sound sources used for exploratory drilling have different properties and are unable to be “powered down” like airgun arrays or shutdown instantaneously without posing other risks to operational and human safety. However, Shell plans to use PSOs (formerly referred to as marine mammal observers) onboard the drillship and the various support vessels to monitor marine mammals and their responses to industry activities and to initiate mitigation measures (for ZVSP activities) should in-field measurements of the operations indicate that such measures are necessary. Additional details on the PSO program are described in the “Monitoring and Reporting” section found later in this document. Also, for the ZVSP activities, Shell will implement standard mitigation procedures, such as ramp ups, power downs, and shutdowns.

A ramp up of an airgun array provides a gradual increase in sound levels and involves a step-wise increase in the number and total volume of airguns firing until the full volume is achieved. The purpose of a ramp up (or “soft start”) is to “warn” cetaceans and pinnipeds in the vicinity of the airguns and to provide the time for them to leave the area and thus avoid any potential injury or impairment of their hearing abilities.

During the ZVSP surveys, Shell will ramp up the airgun arrays slowly. Full ramp ups (

i.e.,

from a cold start when no airguns have been firing) will begin by firing a single airgun in the array. A full ramp up will not begin until there has been a minimum of 30 minutes of observation of the 180-dB and 190-dB exclusion zones for cetaceans and pinnipeds, respectively, by PSOs to assure that no marine mammals are present. The entire exclusion zone must be visible during the 30-minute lead-in to a full ramp up. If the entire exclusion zone is not visible, then ramp up from a cold start cannot begin. If a marine mammal(s) is sighted within the exclusion zone during the 30-minute watch prior to ramp up, ramp up will be delayed until the marine mammal(s) is sighted outside of the applicable exclusion zone or the animal(s) is not sighted for at least 15 minutes for small

odontocetes and pinnipeds or 30 minutes for baleen whales.

A power down is the immediate reduction in the number of operating energy sources from all firing to some smaller number. A shutdown is the immediate cessation of firing of all energy sources. The arrays will be immediately powered down whenever a marine mammal is sighted approaching close to or within the applicable exclusion zone of the full arrays but is outside the applicable exclusion zone of the single source. If a marine mammal is sighted within the applicable exclusion zone of the single energy source, the entire array will be shutdown (

i.e.,

no sources firing). The same 15- and 30-minute sighting times described for ramp up also apply to starting the airguns again after either a power down or shutdown.

Additional mitigation measures include: (1) Reducing speed and/or changing course if a whale is sighted within 300 yards (274 m) from a vessel; (2) reducing speed in inclement weather; (3) checking the water immediately adjacent to the vessel(s) to ensure that no whales will be injured when the propellers are engaged; (4) resuming full activity (

e.g.,

full support vessel speed) only after marine mammals are confirmed to be outside the safety zone; (5) implementing flight restrictions prohibiting aircraft from flying below 1,500 ft (457 m) altitude (except during marine mammal monitoring, takeoffs and landings, or in emergency situations); and (6) keeping vessels anchored when approached by marine mammals to avoid the potential for avoidance reactions by such animals.

Shell will also implement additional mitigation measures to ensure no unmitigable adverse impact on the availability of affected species or stocks for taking for subsistence uses. Those measures are described in the “Impact on Availability of Affected Species or Stock for Taking for Subsistence Uses” section found later in this document.

Oil Spill Response Plan

In accordance with BSEE regulations, Shell has developed an OSRP for its Chukchi Sea exploration drilling program. A copy of this document can be found on the Internet at:

http://www.bsee.gov/OSRP/Shell-Chukchi-OSRP.aspx

. Additionally, in its POC, Shell has agreed to several mitigation measures in order to reduce impacts during the response efforts in the unlikely event of an oil spill. Those measures are detailed in the “

Plan of Cooperation (POC)”

section found later in this document. In the unlikely event of a spill, Shell has also agreed to operate, to the maximum extent practicable, in accordance with NOAA's Marine Mammal Oil Spill Response Guidelines, which are available on the Internet at:

http://www.nmfs.noaa.gov/pr/pdfs/health/eis_appendixl.pdf

. BSEE issued approval of Shell's Chukchi Sea OSRP on February 17, 2012. That approval was issued after review of the plan by BSEE in cooperation with other Federal and state agency partners, including NOAA. Many of the changes to the approved OSRP reflect comments from NOAA, such as revising the worst case discharge scenario and providing trajectories of the worst case discharge over a 30-day period instead of a 72-hour period.

NMFS has carefully evaluated Shell's proposed mitigation measures and considered a range of other measures in the context of ensuring that NMFS prescribes the means of effecting the least practicable impact on the affected marine mammal species and stocks and their habitat. Our evaluation of potential measures included consideration of the following factors in relation to one another:

• The manner in which, and the degree to which, the successful implementation of the measure is expected to minimize adverse impacts to marine mammals;

• The proven or likely efficacy of the specific measure to minimize adverse impacts as planned; and

• The practicability of the measure for applicant implementation.

Measures to ensure availability of such species or stock for taking for certain subsistence uses are discussed later in this document (see “Impact on Availability of Affected Species or Stock for Taking for Subsistence Uses” section).

Monitoring and Reporting

In order to issue an ITA for an activity, Section 101(a)(5)(D) of the MMPA states that NMFS must, where applicable, set forth “requirements pertaining to the monitoring and reporting of such taking”. The MMPA implementing regulations at 50 CFR 216.104 (a)(13) indicate that requests for ITAs must include the suggested means of accomplishing the necessary monitoring and reporting that will result in increased knowledge of the species and of the level of taking or impacts on populations of marine mammals that are expected to be present in the action area.

Monitoring Measures

The monitoring plan proposed by Shell can be found in the 4MP (Attachment C of Shell's application; see

ADDRESSES

). Shell's revised 4MP is also available to the public (see

ADDRESSES

). The plan was modified based on comments received from the peer review panel (see the “

Monitoring Plan Peer Review”

section later in this document) and based on voluntary changes committed to by Shell. A summary of the primary components of the plan can be found in the Notice of Proposed IHA (76 FR 69958, November 9, 2011). A shorter description is contained here, with only components of the 4MP that have been modified summarized in greater detail here.

(1) Vessel-Based PSOs

Vessel-based monitoring for marine mammals will be done by trained PSOs throughout the period of drilling operations on all vessels. PSOs will monitor the occurrence and behavior of marine mammals near the drillship during all daylight periods during operation and during most daylight periods when drilling operations are not occurring. PSO duties will include watching for and identifying marine mammals, recording their numbers, distances, and reactions to the drilling operations. A sufficient number of PSOs will be required onboard each vessel and specifically onboard the drillship and ice management vessels to meet the following criteria: (1) 100% monitoring coverage during all periods of drilling operations in daylight; (2) maximum of 4 consecutive hours on watch per PSO; and (3) maximum of 12 hours of watch time per day per PSO. Shell anticipates that there will be provision for crew rotation at least every 3-6 weeks to avoid observer fatigue.

PSOs will watch for marine mammals from the best available vantage point on the drillship and support vessels. Maximizing time with eyes on the water is strongly promoted during training and is a goal of the PSO program. Each ship will have voice recorders available to PSOs. This will allow PSOs to remain focused on the water in situations where a number of sightings occur together. Additionally, Shell has transitioned entirely to real-time electronic data recording and automated as much of the process as possible to minimize time spent recording data as opposed to focusing eyes on the water.

PSOs are instructed to identify animals as unknown when appropriate rather than strive to identify an animal when there is significant uncertainty. Shell also asks that they provide any sightings cues they used and any distinguishable features of the animal even if they are not able to identify the animal and record it as unidentified. Emphasis is also placed on recording

what was not seen, such as dorsal features.

PSOs will be able to plot sightings in near real-time for their vessel. Significant sightings from key vessels (drill rigs, ice management, anchor handlers and aircraft) will be relayed between platforms to keep observers aware of animals that may be in or near the area but may not be visible to the observer at any one time. Emphasis will be placed on relaying sightings with the greatest potential to involve mitigation or reconsideration of a vessel's course (

e.g.,

large group of bowheads, walruses on ice). Data will also be collected to further evaluate night vision equipment.

(2) Coastal and Offshore Aerial Survey Programs

In its original 4MP, Shell proposed conducting a coastal aerial survey program. Since drafting that original 4MP, Shell has agreed to conduct an offshore aerial photographic survey program. Slight changes to the originally proposed coastal aerial program are noted here, along with details on the newly included offshore photographic survey.

Coastal Aerial Survey

—Recent aerial surveys of marine mammals in the Chukchi Sea were conducted over coastal areas to approximately 23 mi (37 km) offshore in 2006-2008 and 2010 in support of Shell's summer seismic exploration activities. These surveys were designed to provide data on the distribution and abundance of marine mammals in nearshore waters of the Chukchi Sea. Shell proposes to conduct an aerial survey program in the Chukchi Sea in 2012 that would be similar to the previous programs.

The current aerial survey program wil

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