[Federal Register Volume 76, Number 215 (Monday, November 7, 2011)]
[Notices]
[Pages 68974-69027]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2011-28641]



[[Page 68973]]

Vol. 76

Monday,

No. 215

November 7, 2011

Part III





Department of Commerce





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National Oceanic and Atmospheric Administration





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 Takes of Marine Mammals Incidental to Specified Activities; Taking 
Marine Mammals Incidental to an Exploration Drilling Program Near 
Camden Bay, Beaufort Sea, AK; Notice

  Federal Register / Vol. 76 , No. 215 / Monday, November 7, 2011 / 
Notices  

[[Page 68974]]


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DEPARTMENT OF COMMERCE

National Oceanic and Atmospheric Administration

RIN 0648-XA804


Takes of Marine Mammals Incidental to Specified Activities; 
Taking Marine Mammals Incidental to an Exploration Drilling Program 
Near Camden Bay, Beaufort Sea, AK;

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

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

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SUMMARY: NMFS received an application from Shell Offshore Inc. (Shell) 
for an Incidental Harassment Authorization (IHA) to take marine 
mammals, by harassment, incidental to offshore exploration drilling on 
Outer Continental Shelf (OCS) leases in the Beaufort Sea, Alaska. 
Pursuant to the Marine Mammal Protection Act (MMPA), NMFS is requesting 
comments on its proposal to issue an IHA to Shell to take, by Level B 
harassment only, eight species of marine mammals during the specified 
activity.

DATES: Comments and information must be received no later than December 
7, 2011.

ADDRESSES: Comments on the application should be addressed to Michael 
Payne, Chief, Permits and Conservation Division, Office of Protected 
Resources, National Marine Fisheries Service, 1315 East-West Highway, 
Silver Spring, MD 20910. The mailbox address for providing email 
comments is [email protected]. NMFS is not responsible for email 
comments sent to addresses other than the one provided here. Comments 
sent via email, including all attachments, must not exceed a 10-
megabyte file size.
    Instructions: All comments received are a part of the public record 
and will generally be posted to http://www.nmfs.noaa.gov/pr/permits/incidental.htm without change. All Personal Identifying Information 
(for example, name, address, etc.) voluntarily submitted by the 
commenter may be publicly accessible. Do not submit Confidential 
Business Information or otherwise sensitive or protected information.
    A copy of the application, which contains several attachments, 
including Shell's marine mammal mitigation and monitoring plan and Plan 
of Cooperation, used in this document may be obtained by writing to the 
address specified above, telephoning the contact listed below (see FOR 
FURTHER INFORMATION CONTACT), or visiting the Internet at: http://www.nmfs.noaa.gov/pr/permits/incidental.htm. Documents cited in this 
notice may 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 May 10, 2011, from Shell for the 
taking, by harassment, of marine mammals incidental to offshore 
exploration drilling on OCS leases in the Beaufort 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 2, 2011. NMFS carefully evaluated Shell's application, 
including their analyses, and determined that the application is 
complete. The September 2, 2011, application is the one available for 
public comment (see ADDRESSES) and considered by NMFS for this proposed 
IHA.
    Shell plans to drill two exploration wells at two drill sites in 
Camden Bay, Beaufort 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 has requested an authorization to take 11 marine mammal 
species by Level B harassment. However, some of these species are not 
expected to be found in the activity area. Therefore, NMFS is proposing 
to authorize take of eight marine mammal species, by Level B 
harassment, incidental to Shell's offshore exploration drilling program 
in Camden Bay. These species include: Beluga whale (Delphinapterus 
leucas); bowhead whale (Balaena mysticetus); gray whale (Eschrichtius 
robustus); 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 north of Point Thomson near Camden Bay in the Beaufort Sea, 
Alaska, during the 2012 open-water season. During the 2012 drilling 
program, Shell plans to complete two exploration wells at two

[[Page 68975]]

drill sites, one well each on the Torpedo prospect (NR06-04 Flaxman 
Island lease block 6610, OCS-Y-1941 [Flaxman Island 6610--Torpedo ``H'' 
or ``J'' drill site]) and the Sivulliq prospect (NR06-04 Flaxman Island 
lease block 6658, OCS-Y 1805 [Flaxman Island 6658--Sivulliq ``N'' or 
``G'' drill sites]). 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.

Exploration Drilling

    Shell plans to drill the Torpedo prospect well (Torpedo ``H'' or 
``J'') first, followed by the Sivulliq well (Sivulliq ``N'' or ``G''), 
unless adverse surface conditions or other factors dictate a reversal 
of drilling sequence. In that case, Shell will mobilize to the Sivulliq 
prospect and drill there first. Because this is an Arctic program, 
weather and ice conditions will dictate actual operations. The Torpedo 
H and J drill sites are located 20.8 and 23.1 mi (33.5 and 37.2 km) 
from shore in water 120 and 124 ft (36.6 and 37.8 m) deep, 
respectively. The Sivulliq G and N drill sites are located 16.6 and 
16.2 mi (26.7 and 26.1 km) from shore in water 110 and 107 ft (33.5 and 
32.6 m) deep, respectively.
(1) Drilling Vessels
    Shell plans to use one of two drilling vessels for its proposed 
2012 Camden Bay exploratory drilling program: The Kulluk (owned by 
Shell and operated by Noble Drilling [Noble]); or the Discoverer (owned 
and operated by Noble). Only one of these drilling vessels would be 
used for the Camden Bay program, not both. Information on each vessel 
is provided next, and additional details can be found in Attachment A 
of Shell's IHA application (see ADDRESSES).
    The Kulluk has an Arctic Class IV hull design, is capable of 
drilling in up to 600 ft (182.9 m) of water and is moored using a 12-
point anchor system. The vessel is 266 ft (81 m) long. The Kulluk's 
mooring system consists of 12 Hepburn winches located on the outboard 
side of the main deck. Anchor wires lead off the bottom of each winch 
drum inboard for approximately 55 ft (16.8 m). The wire is then 
redirected by a sheave, down through a hawse pipe to an underwater, ice 
protected, swivel fairlead. The wire travels from the fairlead directly 
under the hull to the anchor system on the seafloor. The Kulluk would 
have an anchor radius maximum of 3,117 ft (950 m) for the Sivulliq and 
Torpedo drill sites. While on location at the drill sites, the Kulluk 
will be affixed to the seafloor using 12, 15 metric ton Stevpris 
anchors arranged in a radial array.
    The Kulluk is designed to maintain its location in drilling mode in 
moving ice with thickness up to 4 ft (1.2 m) without the aid of any 
active ice management. With the aid of the ice management vessels, the 
Kulluk would be able to withstand more severe ice conditions. In more 
open-water conditions, the Kulluk can maintain its drilling location 
during storm events with wave heights up to 18 ft (5.5 m) while 
drilling, and can withstand wave heights of up to 40 ft (12.2 m) when 
not drilling and disconnected (assuming a storm duration of 24 hours).
    The Discoverer is a true drillship and is a largely self-contained 
drillship that offers full accommodations for a crew of up to 140 
persons. The Discoverer is 514 ft (156.7 m) long with a maximum height 
(above keel) of 274 ft (83.7 m). It is an anchored drillship with an 8-
point anchored mooring system and would likely have a maximum anchor 
radius of 2,969-2,986 ft (905-910 m) at either the Sivulliq or Torpedo 
drill sites. While on location at the drill sites, the Discoverer will 
be affixed to the seafloor using eight 7,000 kg (7.7 ton) Stevpris 
anchors arranged in a radial array. The underwater fairleads prevent 
ice fouling of the anchor lines. Turret mooring allows orientation of 
the vessel's bow into the prevailing ice drift direction to present 
minimum hull exposure to drifting ice. The vessel is rotated around the 
turret by hydraulic jacks. Rotation can be augmented by the use of the 
fitted bow and stern thrusters. The hull has been reinforced for ice 
resistance. Ice-strengthened sponsons have been retrofitted to the 
ship's hull.
(2) Support Vessels
    During the 2012 drilling season, the Kulluk or Discoverer will be 
attended by 11 vessels that will be used for ice-management, anchor 
handling, oil spill response (OSR), refueling, resupply, drill mud/
cuttings and wastewater transfer, equipment and waste holding, and 
servicing of the drilling operations. Tables 1-1a and 1-1b in Shell's 
application provide lists of the support vessels to be used during the 
drilling program and OSR vessels. The workboats associated with OSR 
training (which are stored on an OSR barge) are not counted among the 
11 attending vessels. All vessels are intended to be either in transit 
or staged (i.e., on anchor) in the Beaufort Sea during the exploration 
drilling activities. The oil spill tanker (OST) would be staged such 
that it would arrive at a recovery site, if needed, within 24 hours of 
departure from the staging location. The purpose of the OST would be to 
provide a place to store large volumes of recovered crude oil, emulsion 
and free water in the unlikely event of a spill, and OSR operations. 
Additional information on Shell's fleet of oil spill response vessels 
can be found in the IHA application.
    The M/V Nordica (Nordica) or a similar vessel will serve as the 
primary ice management vessel in support of the Kulluk or Discoverer. 
Hull 247 or a similar vessel will provide anchor handling duties, serve 
as the berthing (accommodations) vessel for the OSR crew, and will also 
serve as a secondary ice management vessel by managing smaller ice 
floes that may pose a potential safety issue to the drillship and the 
support vessels servicing the drillship. This vessel will also provide 
supplemental oil recovery capability (Vessel of Opportunity Skimming 
System [VOSS]). When managing ice, the Nordica (or similar vessel) and 
Hull 247 will generally be confined to a 40[deg] arc up to 3.1 mi (4.9 
km) upwind originating at the drilling vessel (see Figure 1-3 in 
Shell's application). It is anticipated that the ice management vessels 
will be managing ice for up to 38% of the time when within 25 mi (40 
km) of the Kulluk or Discoverer. Active ice management involves using 
the ice management vessel to steer larger floes so that their path does 
not intersect with the drill site. Around-the-clock ice forecasting 
using real-time satellite coverage (available through Shell Ice and 
Weather Advisory Center [SIWAC]) will support the ice management 
duties. When the Nordica and Hull 247 are not needed for ice 
management, they will reside outside the 25 mi (40 km) radius from the 
Kulluk or Discoverer if it is safe to do so. These vessels will enter 
and exit the Beaufort Sea with the Kulluk or Discoverer.
    The exploration drilling operations will require the transfer of 
supplies between either the Deadhorse/West Dock shorebase or Dutch 
Harbor and the drillship (either the Kulluk or Discoverer). While the 
Kulluk or Discoverer is anchored at a drill site, Shell anticipates 24 
visits/tie-ups (if the Kulluk is the drilling vessel being used) or 8 
visits/tie-ups (if the Discoverer is being used) throughout the 
drilling season from support vessels. During resupply, mud/cuttings and 
other waste streams will be transferred to a deck barge or waste barge 
for temporary storage, which will be brought south for disposal at the 
end of the drilling season. Additional information on the resupply and 
waste removal vessels can be found in Shell's application. Removal of 
waste and resupply to the

[[Page 68976]]

drilling vessels will be conducted the same way regardless of drilling 
vessel.
(3) Aircraft
    An AW139 or Sikorsky S-92 helicopter based in Deadhorse will be 
used for flights between the shorebase and drill sites. It is expected 
that on average, up to two flights per day (approximately 12 flights 
per week) will be necessary to transport supplies and rotate crews. A 
Sikorsky S-92 based in Barrow will be used for search and rescue 
operations. Marine mammal monitoring flights will utilize a de 
Havilland Twin Otter aircraft. The de Havilland Twin Otter is expected 
to fly daily. Table 1-1c in Shell's application presents the aircraft 
planned to support the exploration drilling program.

Zero-Offset Vertical Seismic Profile

    At the end of each drill hole, Shell may conduct a geophysical 
survey referred to as ZVSP at each drill site where a well is drilled 
in 2012. During ZVSP surveys, an airgun array is deployed at a location 
near or adjacent to the drilling vessel, while receivers are placed 
(temporarily anchored) in the wellbore. The sound source (airgun array) 
is fired repeatedly, and the reflected sonic waves are recorded by 
receivers (geophones) located in the wellbore. The geophones, typically 
in a string, are then raised up to the next interval in the wellbore, 
and the process is repeated until the entire wellbore has been 
surveyed. The purpose of the ZVSP is to gather geophysical information 
at various depths, which can then be used to tie-in or ground-truth 
geophysical information from the previous seismic surveys with 
geological data collected within the wellbore.
    Shell intends to conduct a particular form of vertical seismic 
profile known as a ZVSP, in which the sound source is maintained at a 
constant location near the wellbore (see Figure 1-2 in Shell's 
application). A typical sound source that would be used by Shell in 
2012 is the ITAGA eight-airgun array, which consists of four 150 in\3\ 
airguns and four 40 in\3\ airguns. These airguns can be activated in 
any combination, and Shell intends to utilize the minimum airgun volume 
required to obtain an acceptable signal. Current specifications of the 
array are provided in Table 1-2 of Shell's application. The airgun 
array is depicted within its frame or sled, which is approximately 6 ft 
x 5 ft x 10 ft (1.8 m x 1.5 m x 3 m) (see photograph in Shell's 
application). Typical receivers would consist of a Schlumberger 
wireline four level Vertical Seismic Imager (VSI) tool, which has four 
receivers 50-ft (15-m) apart.
    A ZVSP survey is normally conducted at each well after total depth 
is reached but may be conducted at a shallower depth. For each survey, 
Shell plans to deploy the airgun array over the side of the Kulluk or 
Discoverer with a crane (sound source will be 50-200 ft [15-61 m] from 
the wellhead depending on crane location) to a depth of approximately 
10-23 ft (3-7 m) below the water surface. The VSI, with its four 
receivers, will be temporarily anchored in the wellbore at depth. The 
sound source will be pressured up to 2,000 pounds per square inch (psi) 
and activated 5-7 times at approximately 20-second intervals. The VSI 
will then be moved to the next interval of the wellbore and reanchored, 
after which the airgun array will again be activated 5-7 times. This 
process will be repeated until the entire well bore is surveyed in this 
manner. The interval between anchor points for the VSI usually is 
between 200 and 300 ft (61 and 91 m). A normal ZVSP survey is conducted 
over a period of about 10-14 hours, depending on the depth of the well 
and the number of anchoring points. Therefore, considering a few 
different scenarios, the airgun array could be fired between 117 and 
245 times during the 10-14 hour period. For example, a 7,000-ft 
(2,133.6-m) well with 200-ft (61-m) spacing and seven activations per 
station would result in the airgun array being fired 245 times to 
survey the entire well. That same 7,000-ft (2,133.6-m) well with 300-ft 
(91-m) spacing and five activations would result in the airgun array 
being fired 117 times to survey the entire well. The remainder of the 
time during those 10-14 hours when the airgun is not firing is used to 
move and anchor the geophone array.

Ice Management and Forecasting

    Shell recognizes that the drilling program is located in an area 
that is characterized by active sea ice movement, ice scouring, and 
storm surges. In anticipation of potential ice hazards that may be 
encountered, Shell has developed and will implement an Ice Management 
Plan (IMP; see Attachment B in Shell's IHA application) to ensure real-
time ice and weather forecasting is conducted in order to identify 
conditions that might put operations at risk and will modify its 
activities accordingly. The IMP also contains ice threat classification 
levels depending on the time available to suspend drilling operations, 
secure the well, and escape from advancing hazardous ice. Real-time ice 
and weather forecasting will be available to operations personnel for 
planning purposes and to alert the fleet of impending hazardous ice and 
weather conditions. Ice and weather forecasting is provided by SIWAC. 
The center is continuously manned by experienced personnel, who rely on 
a number of data sources for ice forecasting and tracking, including:
     Radarsat and Envisat data--satellites with Synthetic 
Aperture Radar, providing all-weather imagery of ice conditions with 
very high resolution;
     Moderate Resolution Imaging Spectroradiometer--a satellite 
providing lower resolution visual and near infrared imagery;
     Aerial reconnaissance--provided by specially deployed 
fixed wing or rotary wing aircraft for confirmation of ice conditions 
and position;
     Reports from ice specialists on the ice management and 
anchor handling vessels and from the ice observer on the drillship;
     Incidental ice data provided by commercial ships 
transiting the area; and
     Information from NOAA ice centers and the University of 
Colorado.
    Drift ice will be actively managed by ice management vessels, 
consisting of an ice management vessel and an anchor handling vessel. 
Ice management for safe operation of Shell's planned exploration 
drilling program will occur far out in the OCS, remote from the 
vicinities of any routine marine vessel traffic in the Beaufort Sea 
causing no threat to public safety or services that occurs near to 
shore. Shell vessels will also communicate movements and activities 
through the 2012 North Slope Communications Centers. Management of ice 
by ice management vessels will occur during a drilling season 
predominated by open water and thus is not expected to contribute to 
ice hazards, such as ridging, override, or pileup in an offshore or 
nearshore environment.
    The ice-management/anchor handling vessels would manage the ice by 
deflecting any ice floes that could affect the Kulluk or Discoverer 
when it is drilling and would also handle the Kulluk's or Discoverer's 
anchors during connection to and separation from the seafloor. When 
managing ice, the ice management and anchor handling vessels will 
generally be operating at a 40[deg] arc up to 3.1 mi (4.9 km) upwind 
originating at the Kulluk or Discoverer (see Figure 1-3 in Shell's 
application).
    It is anticipated that the ice management vessels will be managing 
ice for 38% of the time when within 25 mi (40 km) of the Kulluk or 
Discoverer.

[[Page 68977]]

The ice floe frequency and intensity are unpredictable and could range 
from no ice to ice sufficiently dense that the fleet has insufficient 
capacity to continue operating, and the Kulluk or Discoverer would need 
to disconnect from its anchors and move off site. If ice is present, 
ice management activities may be necessary in early July and towards 
the end of operations in late October, but it is not expected to be 
needed throughout the proposed drilling season. Shell has indicated 
that when ice is present at the drill site, ice disturbance will be 
limited to the minimum needed to allow drilling to continue. First-year 
ice (i.e., ice that formed in the most recent autumn-winter period) 
will be the type most likely to be encountered. The ice management 
vessels will be tasked with managing the ice so that it will flow 
easily around and past the Kulluk or Discoverer without building up in 
front of or around it. This type of ice is managed by the ice 
management vessel continually moving back and forth across the drift 
line, directly up-drift of the Kulluk or Discoverer and making turns at 
both ends. During ice management, the vessel's propeller is rotating at 
approximately 15-20 percent of the vessel's propeller rotation 
capacity. Ice management occurs with slow movements of the vessel using 
lower power and therefore slower propeller rotation speed (i.e., lower 
cavitation), allowing for fewer repositions of the vessel, thereby 
reducing cavitation effects in the water. Occasionally, there may be 
multi-year ice (i.e., ice that has survived at least one summer melt 
season) ridges that would be managed at a much slower speed than that 
used to manage first-year ice.
    During Camden Bay exploration drilling operations, Shell has 
indicated that they do not intend to conduct any icebreaking 
activities; rather, Shell would deploy its support vessels to manage 
ice as described here. As detailed in Shell's IMP (see Attachment B of 
Shell's IHA application), actual breaking of ice would occur only in 
the unlikely event that ice conditions in the immediate vicinity of 
operations create a safety hazard for the drilling vessel. In such a 
circumstance, operations personnel will follow the guidelines 
established in the IMP to evaluate ice conditions and make the formal 
designation of a hazardous, ice alert condition, which would trigger 
the procedures that govern any actual icebreaking operations. 
Historical data relative to ice conditions in the Beaufort Sea in the 
vicinity of Shell's planned operations, and during the timeframe for 
those operations, establish that there is a very low probability (e.g., 
minimal) for the type of hazardous ice conditions that might 
necessitate icebreaking (e.g., records of the National Naval Ice Center 
archives). This probability could be greater at the shoulders of the 
drilling season (early July or late October); therefore, for purposes 
of evaluating possible impacts of the planned activities, Shell has 
assumed limited icebreaking activities for a very limited period of 
time, and estimated incidental takes of marine mammals from such 
activities.

Timeframe of Activities

    Shell's base plan is for the Kulluk or Discoverer and the 
associated support vessels to transit through the Bering Strait, after 
July 1, 2012, then through the Chukchi Sea, around Pt. Barrow, and east 
through the Alaskan Beaufort Sea, before arriving on location at the 
Torpedo ``H'' location on or about July 10, or Sivulliq ``N'' if 
adverse surface conditions or other factors dictate a reversal of 
drilling sequence. At the completion of the drilling season on or 
before October 31, 2012, one or two ice management vessels, along with 
various support vessels, such as the OSR fleet, will accompany the 
Kulluk or Discoverer as it travels west through the Beaufort Sea, then 
south through the Chukchi Sea and the Bering Strait. Subject to ice 
conditions, alternate exit routes may be considered. Shell has planned 
a suspension of all operations beginning on August 25 for the Nuiqsut 
(Cross Island) and Kaktovik subsistence bowhead whale hunts. During the 
suspension for the whale hunts, the drilling fleet will leave the 
Camden Bay project area, will move to a location at or north of 71.25 
[deg] N. latitude and at or west of 146.4 [deg] W. longitude and will 
return to resume activities after the Nuiqsut (Cross Island) and 
Kaktovik subsistence bowhead whale hunts conclude. Shell will consult 
with the Whaling Captain's Associations of Kaktovik and Nuiqsut to 
ascertain the conclusion of their respective fall subsistence bowhead 
whale hunts.
    Shell will cease drilling on or before October 31, after which the 
Kulluk or Discoverer will exit the Alaskan Beaufort Sea. In total, 
Shell anticipates that the exploration drilling program will require 
approximately 78 drilling days, excluding weather delays, the shutdown 
period to accommodate the fall bowhead whale harvests at Kaktovik and 
Cross Island (Nuiqsut), or other operational delays. Time to conduct 
the ZVSP surveys is included in the 78 drilling days. Shell assumes 
approximately 11 additional days will be needed for drillship 
mobilization, drillship moves between locations, and drillship 
demobilization.
    Activities associated with the 2012 Camden Bay, Beaufort Sea, 
exploration drilling program include operation of the drillship (either 
the Kulluk or Discoverer), associated support vessels, crew change 
support, and re-supply, ZVSP surveys, and icebreaking. The Kulluk or 
Discoverer will remain at the location of the designated exploration 
drill sites except when mobilizing and demobilizing to and from Camden 
Bay, transiting between drill sites, and temporarily moving off 
location if it is determined ice conditions require such a move to 
ensure the safety of personnel and/or the environment in accordance 
with Shell's IMP. Ice management vessels, anchor tenders, and OSR 
vessels will remain in close proximity to the drillship during drilling 
operations.

Exploratory Drilling Program Sound Characteristics

    Potential impacts to marine mammals could occur from the noise 
produced by the drillship and its support vessels (including the 
icebreakers), aircraft, and the airgun array during ZVSP surveys. The 
drillship produces continuous noise into the marine environment. NMFS 
currently uses a threshold of 120 dB re 1 [micro]Pa (rms) for the onset 
of Level B harassment from continuous sound sources. This 120 dB 
threshold is also applicable for the icebreakers when actively managing 
or breaking ice. The drilling vessel to be used will be either the 
Kulluk or the Discoverer. The two vessels are likely to introduce 
somewhat different levels of sound into the water during the 
exploration drilling activities. The airgun array proposed to be used 
by Shell for the ZVSP surveys produces pulsed noise into the marine 
environment. NMFS currently uses a threshold of 160 dB re 1 [micro]Pa 
(rms) for the onset of Level B harassment from pulsed sound sources.
(1) Drilling Sounds
    Exploratory drilling will be conducted from the Kulluk or 
Discoverer, vessels specifically designed for such operations in the 
Arctic. Underwater sound propagation results from the use of 
generators, drilling machinery, and the rig itself. Received sound 
levels during vessel-based operations may fluctuate depending on the 
specific type of activity at a given time and aspect from the vessel. 
Underwater sound levels may also depend on the specific equipment in 
operation. Lower sound levels have been reported during well logging 
than during drilling operations

[[Page 68978]]

(Greene, 1987b), and underwater sound levels appeared to be lower at 
the bow and stern aspects than at the beam (Greene, 1987a).
    Most drilling sounds generated from vessel-based operations occur 
at relatively low frequencies below 600 Hz although tones up to 1,850 
Hz were recorded by Greene (1987a) during drilling operations in the 
Beaufort Sea. At a range of 558 ft (170 m) the 20-1000 Hz band level 
was 122-125 dB for the drillship Explorer I. Underwater sound levels 
were slightly higher (134 dB) during drilling activity from the 
Northern Explorer II at a range of 656 ft (200 m), although tones were 
only recorded below 600 Hz. Underwater sound measurements from the 
Kulluk at 0.62 mi (1 km) were higher (143 dB) than from the other two 
vessels. Sounds from the Kulluk were measured in the Beaufort Sea in 
1986 and reported by Greene (1987a). The back propagated broadband 
source level from the measurements (185.5 dB re 1 [micro]Pa at 1 m 
(rms); reported from the 1/3-octave band levels), which included sounds 
from a support vessel operating nearby, were used to model sound 
propagation at the Sivulliq prospect near Camden Bay.
    Sound measurements from the Discoverer have not previously been 
conducted in the Arctic. However, measurements of sounds produced by 
the Discoverer were made in the South China Sea in 2009 (Austin and 
Warner, 2010). The results of those measurements were used to model the 
sound propagation from the Discoverer (including a nearby support 
vessel) at planned exploration drilling locations in the Beaufort Sea 
(Warner and Hannay, 2011). Broadband source levels of sounds produced 
by the Discoverer varied by activity and direction from the ship but 
were generally between 177 and 185 dB re 1 [mu]Pa at 1 m (rms) (Austin 
and Warner, 2010). Once on location at the drill sites in Camden Bay, 
Shell plans to take measurements of the drillship (either the Kulluk or 
Discoverer) to quantify the absolute sound levels produced by drilling 
and to monitor their variations with time, distance, and direction from 
the drilling vessel.
(2) Vessel Sounds
    In addition to the drillship, various types of vessels will be used 
in support of the operations, including ice management vessels, anchor 
handlers, offshore supply vessels, barges and tugs, and OSR vessels. 
Sounds from boats and vessels have been reported extensively (Greene 
and Moore, 1995; Blackwell and Greene, 2002, 2005, 2006). Numerous 
measurements of underwater vessel sound have been performed in support 
of recent industry activity in the Chukchi and Beaufort Seas. Results 
of these measurements were reported in various 90-day and comprehensive 
reports since 2007 (e.g., Aerts et al., 2008; Hauser et al., 2008; 
Brueggeman, 2009; Ireland et al., 2009). For example, Garner and Hannay 
(2009) estimated sound pressure levels of 100 dB at distances ranging 
from approximately 1.5 to 2.3 mi (2.4 to 3.7 km) from various types of 
barges. MacDonald et al. (2008) estimated higher underwater sound 
pressure levels (SPLs) from the seismic vessel Gilavar of 120 dB at 
approximately 13 mi (21 km) from the source, although the sound level 
was only 150 dB at 85 ft (26 m) from the vessel. Like other industry-
generated sound, underwater sound from vessels is generally at 
relatively low frequencies.
    The primary sources of sounds from all vessel classes are propeller 
cavitation, propeller singing, and propulsion or other machinery. 
Propeller cavitation is usually the dominant noise source for vessels 
(Ross, 1976). Propeller cavitation and singing are produced outside the 
hull, whereas propulsion or other machinery noise originates inside the 
hull. There are additional sounds produced by vessel activity, such as 
pumps, generators, flow noise from water passing over the hull, and 
bubbles breaking in the wake. Icebreakers contribute greater sound 
levels during icebreaking activities than ships of similar size during 
normal operation in open water (Richardson et al., 1995a). This higher 
sound production results from the greater amount of power and propeller 
cavitation required when operating in thick ice.
    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 [mu]Pa at 1 m (Greene, 1987a; Richardson et al., 1995a).
    Sound levels during ice management activities would not be as 
intense as during icebreaking, and the resulting effects to marine 
species would be less significant in comparison. During ice management, 
the vessel's propeller is rotating at approximately 15-20 percent of 
the vessel's propeller rotation capacity. Instead of actually breaking 
ice, during ice management, the vessel redirects and repositions the 
ice by pushing it away from the direction of the drillship at slow 
speeds so that the ice floe does not slip past the vessel bow. 
Basically, ice management occurs at slower speed, lower power, and 
slower propeller rotation speed (i.e., lower cavitation), allowing for 
fewer repositions of the vessel, thereby reducing cavitation effects in 
the water than would occur during icebreaking. Once on location at the 
drill sites in Camden Bay, Shell plans to measure the sound levels 
produced by vessels operating in support of drilling operations. These 
vessels will include crew change vessels, tugs, ice management vessels, 
and OSR vessels.
(3) Aircraft Sound
    Helicopters may be used for personnel and equipment transport to 
and from the drillship. Under calm conditions, rotor and engine sounds 
are coupled into the water within a 26[deg] cone beneath the aircraft. 
Some of the sound will transmit beyond the immediate area, and some 
sound will enter the water outside the 26[deg] area when the sea 
surface is rough. However, scattering and absorption will limit lateral 
propagation in the shallow water.
    Dominant tones in noise spectra from helicopters are generally 
below 500 Hz (Greene and Moore, 1995). Harmonics of the main rotor and 
tail rotor usually dominate the sound from helicopters; however, many 
additional tones associated with the engines and other rotating parts 
are sometimes present.
    Because of doppler shift effects, the frequencies of tones received 
at a stationary site diminish when an aircraft passes overhead. The 
apparent frequency is increased while the aircraft approaches and is 
reduced while it moves away.
    Aircraft flyovers are not heard underwater for very long, 
especially when compared to how long they are heard in air as the 
aircraft approaches an observer. Helicopters flying to and from the 
drillship will generally maintain straight-line routes at altitudes of 
at least 1,500 ft (457 m) above sea level, thereby limiting the 
received levels at and below the surface. Aircraft travel would be 
controlled by Federal Aviation Administration approved flight paths.
(4) Vertical Seismic Profile Sound
    A typical eight airgun array (4 x 40 in\3\ airguns and 4 x 150 
in\3\ airguns, for a total discharge volume of 760 in\3\) would be used 
to perform ZVSP surveys, if conducted after the completion of each 
exploratory well. Typically, a single ZVSP survey will be performed 
when the well has reached proposed total depth or final depth; 
although, in some instances, a prior ZVSP will have been performed at a

[[Page 68979]]

shallower depth. A typical survey will last 10-14 hours, depending on 
the depth of the well and the number of anchoring points, and include 
firings of the full array, plus additional firing of a single 40-in\3\ 
airgun to be used as a ``mitigation airgun'' while the geophones are 
relocated within the wellbore. The source level for the airgun array 
proposed for use by Shell will differ based on source depth. At a depth 
of 9.8 ft (3 m), the SPL is 238 dB re 1 [mu]Pa at 1 m, and at a depth 
of 16.4 ft (5 m), the SPL is 241 dB re 1 [mu]Pa at 1 m, with most 
energy between 20 and 140 Hz.
    Airguns function by venting high-pressure air into the water. The 
pressure signature of an individual airgun consists of a sharp rise and 
then fall in pressure, followed by several positive and negative 
pressure excursions caused by oscillation of the resulting air bubble. 
The sizes, arrangement, and firing times of the individual airguns in 
an array are designed and synchronized to suppress the pressure 
oscillations subsequent to the first cycle. Typical high-energy airgun 
arrays emit most energy at 10-120 Hz. However, the pulses contain 
significant energy up to 500-1,000 Hz and some energy at higher 
frequencies (Goold and Fish, 1998; Potter et al., 2007).
    Although there will be several support vessels in the drilling 
operations area, NMFS considers the possibility of collisions with 
marine mammals highly unlikely. Once on location, the majority of the 
support vessels will remain in the area of the drillship throughout the 
2012 drilling season and will not be making trips between the shorebase 
and the offshore vessels. When not needed for ice management/
icebreaking operations, the icebreaker and anchor handler will remain 
approximately 25 mi (40 km) upwind and upcurrent of the drillship. Any 
ice management/icebreaking activity would be expected to occur at a 
distance of 0.6-12 mi (1-19 km) upwind and upcurrent of the drillship. 
As the crew change/resupply activities are considered part of normal 
vessel traffic and are not anticipated to impact marine mammals in a 
manner that would rise to the level of taking, those activities are not 
considered further in this document.

Description of Marine Mammals in the Area of the Specified Activity

    The Beaufort Sea supports a diverse assemblage of marine mammals, 
including: bowhead, gray, beluga, killer (Orcinus orca), minke 
(Balaenoptera acutorostrata), and humpback (Megaptera novaeangliae) 
whales; harbor porpoises; ringed, ribbon, spotted, and bearded seals; 
narwhal (Monodon monoceros); polar bears (Ursus maritimus); and 
walruses (Odobenus rosmarus divergens; see Table 4-1 in Shell's 
application). The bowhead and humpback whales are listed as 
``endangered'' under the Endangered Species Act (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 proposed activity area. On December 10, 2010, 
NMFS published a notice of proposed threatened status for subspecies of 
the ringed seal (75 FR 77476) and a notice of proposed threatened and 
not warranted status for subspecies and distinct population segments of 
the bearded seal (75 FR 77496) in the Federal Register. Neither of 
these two ice seal species is 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 
U.S. Fish and Wildlife Service (USFWS) and are not considered further 
in this Notice of Proposed IHA.
    Of these species, eight are expected to occur in the area of 
Shell's proposed operations. These species include: The bowhead, gray, 
and beluga whales, harbor porpoise, and the ringed, spotted, bearded, 
and ribbon seals. The marine mammal species that is likely to be 
encountered most widely (in space and time) throughout the period of 
the proposed drilling program is the ringed seal. Bowhead whales are 
also anticipated to occur in the proposed project area more frequently 
than the other cetacean species; however, their occurrence is not 
expected until later in the season. Even though harbor porpoise and 
ribbon seals are not typically sighted in Camden Bay, there have been 
recent sightings in the Beaufort Sea near the Prudhoe Bay area, so 
their occurrence could not be completely ruled out. Point Barrow, 
Alaska, is the approximate northeastern extent of the harbor porpoise's 
regular range (Suydam and George, 1992), though there are extralimital 
records east to the mouth of the Mackenzie River in the Northwest 
Territories, Canada, and recent sightings in the Beaufort Sea in the 
vicinity of Prudhoe Bay during surveys in 2007 and 2008 (Christie et 
al., 2009). Two ribbon seal sightings were reported during vessel-based 
activities near Prudhoe Bay in 2008 (Savarese et al., 2009). 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).
    Other cetacean species that have been observed in the Beaufort Sea 
but are uncommon or rarely identified in the project area include 
narwhal and killer, minke, and humpback whales. These species could 
occur in the project area, but each of these species is uncommon or 
rare in the area and relatively few encounters with these species are 
expected during the exploration drilling program. The narwhal occurs in 
Canadian waters and occasionally in the Beaufort Sea, but it is rare 
there and is not expected to be encountered. There are scattered 
records of narwhal in Alaskan waters, including reports by subsistence 
hunters, where the species is considered extralimital (Reeves et al., 
2002). Humpback and minke whales have recently been sighted in the 
Chukchi Sea but very rarely in the Beaufort Sea. Greene et al. (2007) 
reported and photographed a humpback whale cow/calf pair east of Barrow 
near Smith Bay in 2007, which is the first known occurrence of 
humpbacks in the Beaufort Sea. Savarese et al. (2009) reported one 
minke whale sighting in the Beaufort Sea in 2007 and 2008. Due to the 
rarity of these species in the proposed project area and the remote 
chance they would be affected by Shell's proposed Beaufort Sea drilling 
activities, these species are not discussed further in this proposed 
IHA notice.
    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

[[Page 68980]]

2010 SAR is available at: http://www.nmfs.noaa.gov/pr/pdfs/sars/ak2010.pdf.

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, six marine mammal species 
(three cetacean and three pinniped species) are likely to occur in the 
proposed exploratory drilling area. Of the three cetacean species 
likely to occur in Shell's proposed project area, two are classified as 
low frequency cetaceans (i.e., bowhead and gray whales) and one is 
classified as a mid-frequency cetacean (i.e., beluga whales) (Southall 
et al., 2007).
    Underwater audiograms have been obtained using behavioral methods 
for four species of phocinid seals: The ringed, harbor, harp, and 
northern elephant seals (reviewed in Richardson et al., 1995a; Kastak 
and Schusterman, 1998). Below 30-50 kHz, the hearing threshold of 
phocinids is essentially flat down to at least 1 kHz and ranges between 
60 and 85 dB re 1 [mu]Pa. There are few published data on in-water 
hearing sensitivity of phocid seals below 1 kHz. However, measurements 
for one harbor seal indicated that, below 1 kHz, its thresholds 
deteriorated gradually to 96 dB re 1 [mu]Pa at 100 Hz from 80 dB re 1 
[mu]Pa at 800 Hz and from 67 dB re 1 [mu]Pa at 1,600 Hz (Kastak and 
Schusterman, 1998). More recent data suggest that harbor seal hearing 
at low frequencies may be more sensitive than that and that earlier 
data were confounded by excessive background noise (Kastelein et al., 
2009a,b). If so, harbor seals have considerably better underwater 
hearing sensitivity at low frequencies than do small odontocetes like 
belugas (for which the threshold at 100 Hz is about 125 dB).
    Pinniped call characteristics are relevant when assessing potential 
masking effects of man-made sounds. In addition, for those species 
whose hearing has not been tested, call characteristics are useful in 
assessing the frequency range within which hearing is likely to be most 
sensitive. The three species of seals present in the study area, all of 
which are in the phocid seal group, are all most vocal during the 
spring mating season and much less so during late summer. In each 
species, the calls are at frequencies from several hundred to several 
thousand hertz--above the frequency range of the dominant noise 
components from most of the proposed oil exploration activities.
    Cetacean hearing has been studied in relatively few species and 
individuals. The auditory sensitivity of bowhead, gray, and other 
baleen whales has not been measured, but relevant anatomical and 
behavioral evidence is available. These whales appear to be specialized 
for low frequency hearing, with some directional hearing ability 
(reviewed in Richardson et al., 1995a; Ketten, 2000). Their optimum 
hearing overlaps broadly with the low frequency range where exploration 
drilling activities, airguns, and associated vessel traffic emit most 
of their energy.
    The beluga whale is one of the better-studied species in terms of 
its hearing ability. As mentioned earlier, the auditory bandwidth in 
mid-frequency odontocetes is believed to range from 150 Hz to 160 kHz 
(Southall et al., 2007); however, belugas are most sensitive above 10 
kHz. They have relatively poor sensitivity at the low frequencies 
(reviewed in Richardson et al., 1995a) that dominate the sound from 
industrial activities and associated vessels. Nonetheless, the noise 
from strong low frequency sources is detectable by belugas many 
kilometers away (Richardson and Wursig, 1997). Also, beluga hearing at 
low frequencies in open-water conditions is apparently somewhat better 
than in the captive situations where most hearing studies were 
conducted (Ridgway and Carder, 1995; Au, 1997). If so, low frequency 
sounds emanating from drilling activities may be detectable somewhat 
farther away than previously estimated.
    Call characteristics of cetaceans provide some limited information 
on their hearing abilities, although the auditory range often extends 
beyond the range of frequencies contained in the calls. Also, 
understanding the frequencies at which different marine mammal species 
communicate is relevant for the assessment of potential impacts from 
manmade sounds. A summary of the call characteristics for bowhead, 
gray, and beluga whales is provided next.
    Most bowhead calls are tonal, frequency-modulated sounds at 
frequencies of 50-400 Hz. These calls overlap broadly in frequency with 
the underwater sounds emitted by many of the activities to be performed 
during Shell's proposed exploration drilling program (Richardson et 
al., 1995a). Source levels are quite variable, with the stronger calls 
having source levels up to about 180 dB re 1 [mu]Pa at 1 m. Gray whales 
make a wide variety of calls at frequencies from <100-2,000 Hz (Moore 
and Ljungblad, 1984; Dalheim, 1987).
    Beluga calls include trills, whistles, clicks, bangs, chirps and 
other sounds (Schevill and Lawrence, 1949; Ouellet, 1979; Sjare and 
Smith, 1986a). Beluga whistles have dominant frequencies in the 2-6 kHz 
range (Sjare and Smith, 1986a). This is above the frequency range of 
most of the sound energy produced by the proposed exploratory drilling 
activities and associated vessels. Other beluga call types reported by 
Sjare and Smith (1986a,b) included sounds at mean frequencies ranging 
upward from 1 kHz.
    The beluga also has a very well developed high frequency 
echolocation system, as reviewed by Au (1993). Echolocation signals 
have peak frequencies from 40-120 kHz and broadband source levels of up 
to 219 dB re 1 [mu]Pa-m (zero-peak). Echolocation calls are far above 
the frequency range of the sounds produced by the devices proposed for 
use during Shell's Camden Bay exploratory drilling program. Therefore, 
those industrial sounds are

[[Page 68981]]

not expected to interfere with echolocation.

Potential Effects of the Specified Activity on Marine Mammals

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

Potential Acoustic Effects From Exploratory Drilling Activities

(1) Tolerance
    Numerous studies have shown that underwater sounds from industry 
activities are often readily detectable by marine mammals in the water 
at distances of many kilometers. Numerous studies have also shown that 
marine mammals at distances more than a few kilometers away often show 
no apparent response to industry activities of various types (Miller et 
al., 2005; Bain and Williams, 2006). This is often true even in cases 
when the sounds must be readily audible to the animals based on 
measured received levels and the hearing sensitivity of that mammal 
group. Although various baleen whales, toothed whales, and (less 
frequently) pinnipeds have been shown to react behaviorally to 
underwater sound such as airgun pulses or vessels under some 
conditions, at other times mammals of all three types have shown no 
overt reactions (e.g., Malme et al., 1986; Richardson et al., 1995; 
Madsen and Mohl, 2000; Croll et al., 2001; Jacobs and Terhune, 2002; 
Madsen et al., 2002; Miller et al., 2005). In general, pinnipeds and 
small odontocetes seem to be more tolerant of exposure to some types of 
underwater sound than are baleen whales. Richardson et al. (1995a) 
found that vessel noise does not seem to strongly affect pinnipeds that 
are already in the water. Richardson et al. (1995a) went on to explain 
that seals on haul-outs sometimes respond strongly to the presence of 
vessels and at other times appear to show considerable tolerance of 
vessels, and Brueggeman et al. (1992, cited in Richardson et al., 
1995a) observed ringed seals hauled out on ice pans displaying short-
term escape reactions when a ship approached within 0.25-0.5 mi (0.4-
0.8 km).
(2) Masking
    Masking is the obscuring of sounds of interest by other sounds, 
often at similar frequencies. Marine mammals are highly dependent on 
sound, and their ability to recognize sound signals amid other noise is 
important in communication, predator and prey detection, and, in the 
case of toothed whales, echolocation. Even in the absence of manmade 
sounds, the sea is usually noisy. Background ambient noise often 
interferes with or masks the ability of an animal to detect a sound 
signal even when that signal is above its absolute hearing threshold. 
Natural ambient noise includes contributions from wind, waves, 
precipitation, other animals, and (at frequencies above 30 kHz) thermal 
noise resulting from molecular agitation (Richardson et al., 1995a). 
Background noise also can include sounds from human activities. Masking 
of natural sounds can result when human activities produce high levels 
of background noise. Conversely, if the background level of underwater 
noise is high (e.g., on a day with strong wind and high waves), an 
anthropogenic noise source will not be detectable as far away as would 
be possible under quieter conditions and will itself be masked.
    Although some degree of masking is inevitable when high levels of 
manmade broadband sounds are introduced into the sea, marine mammals 
have evolved systems and behavior that function to reduce the impacts 
of masking. Structured signals, such as the echolocation click 
sequences of small toothed whales, may be readily detected even in the 
presence of strong background noise because their frequency content and 
temporal features usually differ strongly from those of the background 
noise (Au and Moore, 1988, 1990). The components of background noise 
that are similar in frequency to the sound signal in question primarily

[[Page 68982]]

determine the degree of masking of that signal.
    Redundancy and context can also facilitate detection of weak 
signals. These phenomena may help marine mammals detect weak sounds in 
the presence of natural or manmade noise. Most masking studies in 
marine mammals present the test signal and the masking noise from the 
same direction. The sound localization abilities of marine mammals 
suggest that, if signal and noise come from different directions, 
masking would not be as severe as the usual types of masking studies 
might suggest (Richardson et al., 1995a). The dominant background noise 
may be highly directional if it comes from a particular anthropogenic 
source such as a ship or industrial site. Directional hearing may 
significantly reduce the masking effects of these noises by improving 
the effective signal-to-noise ratio. In the cases of high-frequency 
hearing by the bottlenose dolphin, beluga whale, and killer whale, 
empirical evidence confirms that masking depends strongly on the 
relative directions of arrival of sound signals and the masking noise 
(Penner et al., 1986; Dubrovskiy, 1990; Bain et al., 1993; Bain and 
Dahlheim, 1994). Toothed whales, and probably other marine mammals as 
well, have additional capabilities besides directional hearing that can 
facilitate detection of sounds in the presence of background noise. 
There is evidence that some toothed whales can shift the dominant 
frequencies of their echolocation signals from a frequency range with a 
lot of ambient noise toward frequencies with less noise (Au et al., 
1974, 1985; Moore and Pawloski, 1990; Thomas and Turl, 1990; Romanenko 
and Kitain, 1992; Lesage et al., 1999). A few marine mammal species are 
known to increase the source levels or alter the frequency of their 
calls in the presence of elevated sound levels (Dahlheim, 1987; Au, 
1993; Lesage et al., 1993, 1999; Terhune, 1999; Foote et al., 2004; 
Parks et al., 2007, 2009; Di Iorio and Clark, 2009; Holt et al., 2009).
    These data demonstrating adaptations for reduced masking pertain 
mainly to the very high frequency echolocation signals of toothed 
whales. There is less information about the existence of corresponding 
mechanisms at moderate or low frequencies or in other types of marine 
mammals. For example, Zaitseva et al. (1980) found that, for the 
bottlenose dolphin, the angular separation between a sound source and a 
masking noise source had little effect on the degree of masking when 
the sound frequency was 18 kHz, in contrast to the pronounced effect at 
higher frequencies. Directional hearing has been demonstrated at 
frequencies as low as 0.5-2 kHz in several marine mammals, including 
killer whales (Richardson et al., 1995a). This ability may be useful in 
reducing masking at these frequencies. In summary, high levels of noise 
generated by anthropogenic activities may act to mask the detection of 
weaker biologically important sounds by some marine mammals. This 
masking may be more prominent for lower frequencies. For higher 
frequencies, such as that used in echolocation by toothed whales, 
several mechanisms are available that may allow them to reduce the 
effects of such masking.
    Masking effects of underwater sounds from Shell's proposed 
activities on marine mammal calls and other natural sounds are expected 
to be limited. For example, beluga whales primarily use high-frequency 
sounds to communicate and locate prey; therefore, masking by low-
frequency sounds associated with drilling activities is not expected to 
occur (Gales, 1982, as cited in Shell, 2009). If the distance between 
communicating whales does not exceed their distance from the drilling 
activity, the likelihood of potential impacts from masking would be low 
(Gales, 1982, as cited in Shell, 2009). At distances greater than 660-
1,300 ft (200-400 m), recorded sounds from drilling activities did not 
affect behavior of beluga whales, even though the sound energy level 
and frequency were such that it could be heard several kilometers away 
(Richardson et al., 1995b). This exposure resulted in whales being 
deflected from the sound energy and changing behavior. These minor 
changes are not expected to affect the beluga whale population 
(Richardson et al., 1991; Richard et al., 1998). Brewer et al. (1993) 
observed belugas within 2.3 mi (3.7 km) of the drilling unit Kulluk 
during drilling; however, the authors do not describe any behaviors 
that may have been exhibited by those animals. Please refer to the 
Arctic Multiple-Sale Draft Environmental Impact Statement (USDOI MMS, 
2008), available on the Internet at: http://www.mms.gov/alaska/ref/EIS%20EA/ArcticMultiSale_209/_DEIS.htm, for more detailed 
information.
    There is evidence of other marine mammal species continuing to call 
in the presence of industrial activity. Annual acoustical 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). Construction, maintenance, and operational 
activities have been occurring from this facility for over 10 years. To 
compensate and reduce masking, some mysticetes may alter the 
frequencies of their communication sounds (Richardson et al., 1995a; 
Parks et al., 2007). Masking processes in baleen whales are not 
amenable to laboratory study, and no direct measurements on hearing 
sensitivity are available for these species. It is not currently 
possible to determine with precision the potential consequences of 
temporary or local background noise levels. However, Parks et al. 
(2007) found that right whales (a species closely related to the 
bowhead whale) altered their vocalizations, possibly in response to 
background noise levels. For species that can hear over a relatively 
broad frequency range, as is presumed to be the case for mysticetes, a 
narrow band source may only cause partial masking. Richardson et al. 
(1995a) note that a bowhead whale 12.4 mi (20 km) from a human sound 
source, such as that produced during oil and gas industry activities, 
might hear strong calls from other whales within approximately 12.4 mi 
(20 km), and a whale 3.1 mi (5 km) from the source might hear strong 
calls from whales within approximately 3.1 mi (5 km). Additionally, 
masking is more likely to occur closer to a sound source, and distant 
anthropogenic sound is less likely to mask short-distance acoustic 
communication (Richardson et al., 1995a).
    Although some masking by marine mammal species in the area may 
occur, the extent of the masking interference will depend on the 
spatial relationship of the animal and Shell's activity. Almost all 
energy in the sounds emitted by drilling and other operational 
activities is at low frequencies, predominantly below 250 Hz with 
another peak centered around 1,000 Hz. Most energy in the sounds from 
the vessels and aircraft to be used during this project is below 1 kHz 
(Moore et al., 1984; Greene and Moore, 1995; Blackwell et al., 2004b; 
Blackwell and Greene, 2006). These frequencies are mainly used by 
mysticetes but not by odontocetes. Therefore, masking effects would 
potentially be more pronounced in the bowhead and gray whales that 
might occur in the proposed project area. If, as described later in 
this document, certain species avoid the proposed drilling locations, 
impacts from masking are anticipated to be low.
(3) Behavioral Disturbance Reactions
    Behavioral responses to sound are highly variable and context-
specific.

[[Page 68983]]

Many different variables can influence an animal's perception of and 
response to (in both nature and magnitude) an acoustic event. An 
animal's prior experience with a sound or sound source affects whether 
it is less likely (habituation) or more likely (sensitization) to 
respond to certain sounds in the future (animals can also be innately 
pre-disposed to respond to certain sounds in certain ways; Southall et 
al., 2007). Related to the sound itself, the perceived nearness of the 
sound, bearing of the sound (approaching vs. retreating), similarity of 
a sound to biologically relevant sounds in the animal's environment 
(i.e., calls of predators, prey, or conspecifics), and familiarity of 
the sound may affect the way an animal responds to the sound (Southall 
et al., 2007). Individuals (of different age, gender, reproductive 
status, etc.) among most populations will have variable hearing 
capabilities and differing behavioral sensitivities to sounds that will 
be affected by prior conditioning, experience, and current activities 
of those individuals. Often, specific acoustic features of the sound 
and contextual variables (i.e., proximity, duration, or recurrence of 
the sound or the current behavior that the marine mammal is engaged in 
or its prior experience), as well as entirely separate factors such as 
the physical presence of a nearby vessel, may be more relevant to the 
animal's response than the received level alone.
    Exposure of marine mammals to sound sources can result in (but is 
not limited to) no response or any of the following observable 
responses: Increased alertness; orientation or attraction to a sound 
source; vocal modifications; cessation of feeding; cessation of social 
interaction; alteration of movement or diving behavior; avoidance; 
habitat abandonment (temporary or permanent); and, in severe cases, 
panic, flight, stampede, or stranding, potentially resulting in death 
(Southall et al., 2007). On a related note, many animals perform vital 
functions, such as feeding, resting, traveling, and socializing, on a 
diel cycle (24-hr cycle). Behavioral reactions to noise exposure (such 
as disruption of critical life functions, displacement, or avoidance of 
important habitat) are more likely to be significant if they last more 
than one diel cycle or recur on subsequent days (Southall et al., 
2007). Consequently, a behavioral response lasting less than one day 
and not recurring on subsequent days is not considered particularly 
severe unless it could directly affect reproduction or survival 
(Southall et al., 2007).
    Detailed studies regarding responses to anthropogenic sound have 
been conducted on humpback, gray, and bowhead whales and ringed seals. 
Less detailed data are available for some other species of baleen 
whales, sperm whales, small toothed whales, and sea otters. The 
following sub-sections provide examples of behavioral responses that 
provide an idea of the variability in behavioral responses that would 
be expected given the different sensitivities of marine mammal species 
to sound.
    Baleen Whales--Richardson et al. (1995b) reported changes in 
surfacing and respiration behavior and the occurrence of turns during 
surfacing in bowhead whales exposed to playback of underwater sound 
from drilling activities. These behavioral effects were localized and 
occurred at distances up to 1.2-2.5 mi (2-4 km).
    Some bowheads appeared to divert from their migratory path after 
exposure to projected icebreaker sounds. Other bowheads however, 
tolerated projected icebreaker sound at levels 20 dB and more above 
ambient sound levels. The source level of the projected sound however, 
was much less than that of an actual icebreaker, and reaction distances 
to actual icebreaking may be much greater than those reported here for 
projected sounds.
    Brewer et al. (1993) and Hall et al. (1994) reported numerous 
sightings of marine mammals including bowhead whales in the vicinity of 
offshore drilling operations in the Beaufort Sea. One bowhead whale 
sighting was reported within approximately 1,312 ft (400 m) of a 
drilling vessel although most other bowhead sightings were at much 
greater distances. Few bowheads were recorded near industrial 
activities by aerial observers. After controlling for spatial 
autocorrelation in aerial survey data from Hall et al. (1994) using a 
Mantel test, Schick and Urban (2000) found that the variable describing 
straight line distance between the rig and bowhead whale sightings was 
not significant but that a variable describing threshold distances 
between sightings and the rig was significant. Thus, although the 
aerial survey results suggested substantial avoidance of the operations 
by bowhead whales, observations by vessel-based observers indicate that 
at least some bowheads may have been closer to industrial activities 
than was suggested by results of aerial observations.
    Richardson et al. (2008) reported a slight change in the 
distribution of bowhead whale calls in response to operational sounds 
on BP's Northstar Island. The southern edge of the call distribution 
ranged from 0.47 to 1.46 mi (0.76 to 2.35 km) farther offshore, 
apparently in response to industrial sound levels. This result however, 
was only achieved after intensive statistical analyses, and it is not 
clear that this represented a biologically significant effect.
    Patenaude et al. (2002) reported fewer behavioral responses to 
aircraft overflights by bowhead compared to beluga whales. Behaviors 
classified as reactions consisted of short surfacings, immediate dives 
or turns, changes in behavior state, vigorous swimming, and breaching. 
Most bowhead reaction resulted from exposure to helicopter activity and 
little response to fixed-wing aircraft was observed. Most reactions 
occurred when the helicopter was at altitudes <= 492 ft (150 m) and 
lateral distances <= 820 ft (250 m; Nowacek et al., 2007).
    During their study, Patenaude et al. (2002) observed one bowhead 
whale cow-calf pair during four passes totaling 2.8 hours of the 
helicopter and two pairs during Twin Otter overflights. All of the 
helicopter passes were at altitudes of 49-98 ft (15-30 m). The mother 
dove both times she was at the surface, and the calf dove once out of 
the four times it was at the surface. For the cow-calf pair sightings 
during Twin Otter overflights, the authors did not note any behaviors 
specific to those pairs. Rather, the reactions of the cow-calf pairs 
were lumped with the reactions of other groups that did not consist of 
calves.
    Richardson et al. (1995b) and Moore and Clarke (2002) reviewed a 
few studies that observed responses of gray whales to aircraft. Cow-
calf pairs were quite sensitive to a turboprop survey flown at 1,000 ft 
(305 m) altitude on the Alaskan summering grounds. In that survey, 
adults were seen swimming over the calf, or the calf swam under the 
adult (Ljungblad et al., 1983, cited in Richardson et al., 1995b and 
Moore and Clarke, 2002). However, when the same aircraft circled for 
more than 10 minutes at 1,050 ft (320 m) altitude over a group of 
mating gray whales, no reactions were observed (Ljungblad et al., 1987, 
cited in Moore and Clarke, 2002). Malme et al. (1984, cited in 
Richardson et al., 1995b and Moore and Clarke, 2002) conducted playback 
experiments on migrating gray whales. They exposed the animals to 
underwater noise recorded from a Bell 212 helicopter (estimated 
altitude=328 ft [100 m]), at an average of three simulated passes per 
minute. The authors observed that whales changed their swimming course 
and sometimes slowed down in response to the playback sound but 
proceeded to migrate past the

[[Page 68984]]

transducer. Migrating gray whales did not react overtly to a Bell 212 
helicopter at greater than 1,394 ft (425 m) altitude, occasionally 
reacted when the helicopter was at 1,000-1,198 ft (305-365 m), and 
usually reacted when it was below 825 ft (250 m; Southwest Research 
Associates, 1988, cited in Richardson et al., 1995b and Moore and 
Clarke, 2002). Reactions noted in that study included abrupt turns or 
dives or both. Green et al. (1992, cited in Richardson et al., 1995b) 
observed that migrating gray whales rarely exhibited noticeable 
reactions to a straight-line overflight by a Twin Otter at 197 ft (60 
m) altitude. Restrictions on aircraft altitude will be part of the 
proposed mitigation measures (described in the ``Proposed Mitigation'' 
section later in this document) during the proposed drilling 
activities, and overflights are likely to have little or no disturbance 
effects on baleen whales. Any disturbance that may occur would likely 
be temporary and localized.
    Southall et al. (2007, Appendix C) reviewed a number of papers 
describing the responses of marine mammals to non-pulsed sound, such as 
that produced during exploratory drilling operations. In general, 
little or no response was observed in animals exposed at received 
levels from 90-120 dB re 1 [micro]Pa (rms). Probability of avoidance 
and other behavioral effects increased when received levels were from 
120-160 dB re 1 [micro]Pa (rms). Some of the relevant reviews contained 
in Southall et al. (2007) are summarized next.
    Baker et al. (1982) reported some avoidance by humpback whales to 
vessel noise when received levels were 110-120 dB (rms) and clear 
avoidance at 120-140 dB (sound measurements were not provided by Baker 
but were based on measurements of identical vessels by Miles and Malme, 
1983).
    Malme et al. (1983, 1984) used playbacks of sounds from helicopter 
overflight and drilling rigs and platforms to study behavioral effects 
on migrating gray whales. Received levels exceeding 120 dB induced 
avoidance reactions. Malme et al. (1984) calculated 10%, 50%, and 90% 
probabilities of gray whale avoidance reactions at received levels of 
110, 120, and 130 dB, respectively. Malme et al. (1986) observed the 
behavior of feeding gray whales during four experimental playbacks of 
drilling sounds (50 to 315 Hz; 21-min overall duration and 10% duty 
cycle; source levels of 156-162 dB). In two cases for received levels 
of 100-110 dB, no behavioral reaction was observed. However, avoidance 
behavior was observed in two cases where received levels were 110-120 
dB.
    Richardson et al. (1990) performed 12 playback experiments in which 
bowhead whales in the Alaskan Arctic were exposed to drilling sounds. 
Whales generally did not respond to exposures in the 100 to 130 dB 
range, although there was some indication of minor behavioral changes 
in several instances.
    McCauley et al. (1996) reported several cases of humpback whales 
responding to vessels in Hervey Bay, Australia. Results indicated clear 
avoidance at received levels between 118 to 124 dB in three cases for 
which response and received levels were observed/measured.
    Palka and Hammond (2001) analyzed line transect census data in 
which the orientation and distance off transect line were reported for 
large numbers of minke whales. The authors developed a method to 
account for effects of animal movement in response to sighting 
platforms. Minor changes in locomotion speed, direction, and/or diving 
profile were reported at ranges from 1,847 to 2,352 ft (563 to 717 m) 
at received levels of 110 to 120 dB.
    Biassoni et al. (2000) and Miller et al. (2000) reported behavioral 
observations for humpback whales exposed to a low-frequency sonar 
stimulus (160- to 330-Hz frequency band; 42-s tonal signal repeated 
every 6 min; source levels 170 to 200 dB) during playback experiments. 
Exposure to measured received levels ranging from 120 to 150 dB 
resulted in variability in humpback singing behavior. Croll et al. 
(2001) investigated responses of foraging fin and blue whales to the 
same low frequency active sonar stimulus off southern California. 
Playbacks and control intervals with no transmission were used to 
investigate behavior and distribution on time scales of several weeks 
and spatial scales of tens of kilometers. The general conclusion was 
that whales remained feeding within a region for which 12 to 30% of 
exposures exceeded 140 dB.
    Frankel and Clark (1998) conducted playback experiments with 
wintering humpback whales using a single speaker producing a low-
frequency ``M-sequence'' (sine wave with multiple-phase reversals) 
signal in the 60 to 90 Hz band with output of 172 dB at 1 m. For 11 
playbacks, exposures were between 120 and 130 dB re 1 [micro]Pa (rms) 
and included sufficient information regarding individual responses. 
During eight of the trials, there were no measurable differences in 
tracks or bearings relative to control conditions, whereas on three 
occasions, whales either moved slightly away from (n = 1) or towards (n 
= 2) the playback speaker during exposure. The presence of the source 
vessel itself had a greater effect than did the M-sequence playback.
    Finally, Nowacek et al. (2004) used controlled exposures to 
demonstrate behavioral reactions of northern right whales to various 
non-pulse sounds. Playback stimuli included ship noise, social sounds 
of conspecifics, and a complex, 18-min ``alert'' sound consisting of 
repetitions of three different artificial signals. Ten whales were 
tagged with calibrated instruments that measured received sound 
characteristics and concurrent animal movements in three dimensions. 
Five out of six exposed whales reacted strongly to alert signals at 
measured received levels between 130 and 150 dB (i.e., ceased foraging 
and swam rapidly to the surface). Two of these individuals were not 
exposed to ship noise, and the other four were exposed to both stimuli. 
These whales reacted mildly to conspecific signals. Seven whales, 
including the four exposed to the alert stimulus, had no measurable 
response to either ship sounds or actual vessel noise.
    Toothed Whales--Most toothed whales have the greatest hearing 
sensitivity at frequencies much higher than that of baleen whales and 
may be less responsive to low-frequency sound commonly associated with 
oil and gas industry exploratory drilling activities. Richardson et al. 
(1995b) reported that beluga whales did not show any apparent reaction 
to playback of underwater drilling sounds at distances greater than 
656-1,312 ft (200-400 m). Reactions included slowing down, milling, or 
reversal of course after which the whales continued past the projector, 
sometimes within 164-328 ft (50-100 m). The authors concluded (based on 
a small sample size) that the playback of drilling sounds had no 
biologically significant effects on migration routes of beluga whales 
migrating through pack ice and along the seaward side of the nearshore 
lead east of Pt. Barrow in spring.
    At least six of 17 groups of beluga whales appeared to alter their 
migration path in response to underwater playbacks of icebreaker sound 
(Richardson et al., 1995b). Received levels from the icebreaker 
playback were estimated at 78-84 dB in the 1/3-octave band centered at 
5,000 Hz, or 8-14 dB above ambient. If beluga whales reacted to an 
actual icebreaker at received levels of 80 dB, reactions would be 
expected to occur at distances on the order of 6.2 mi (10 km). Finley 
et al. (1990) also reported beluga avoidance of icebreaker activities 
in the Canadian High Arctic at distances of

[[Page 68985]]

22-31 mi (35-50 km). In addition to avoidance, changes in dive behavior 
and pod integrity were also noted.
    Patenaude et al. (2002) reported that beluga whales appeared to be 
more responsive to aircraft overflights than bowhead whales. Changes 
were observed in diving and respiration behavior, and some whales 
veered away when a helicopter passed at <= 820 ft (250 m) lateral 
distance at altitudes up to 492 ft (150 m). However, some belugas 
showed no reaction to the helicopter. Belugas appeared to show less 
response to fixed-wing aircraft than to helicopter overflights.
    In reviewing responses of cetaceans with best hearing in mid-
frequency ranges, which includes toothed whales, Southall et al. (2007) 
reported that combined field and laboratory data for mid-frequency 
cetaceans exposed to non-pulse sounds did not lead to a clear 
conclusion about received levels coincident with various behavioral 
responses. In some settings, individuals in the field showed profound 
(significant) behavioral responses to exposures from 90-120 dB, while 
others failed to exhibit such responses for exposure to received levels 
from 120-150 dB. Contextual variables other than exposure received 
level, and probable species differences, are the likely reasons for 
this variability. Context, including the fact that captive subjects 
were often directly reinforced with food for tolerating noise exposure, 
may also explain why there was great disparity in results from field 
and laboratory conditions--exposures in captive settings generally 
exceeded 170 dB before inducing behavioral responses. A summary of some 
of the relevant material reviewed by Southall et al. (2007) is next.
    LGL and Greeneridge (1986) and Finley et al. (1990) documented 
belugas and narwhals congregated near ice edges reacting to the 
approach and passage of icebreaking ships. Beluga whales responded to 
oncoming vessels by (1) Fleeing at speeds of up to 12.4 mi/hr (20 km/
hr) from distances of 12.4-50 mi (20-80 km), (2) abandoning normal pod 
structure, and (3) modifying vocal behavior and/or emitting alarm 
calls. Narwhals, in contrast, generally demonstrated a ``freeze'' 
response, lying motionless or swimming slowly away (as far as 23 mi [37 
km] down the ice edge), huddling in groups, and ceasing sound 
production. There was some evidence of habituation and reduced 
avoidance 2 to 3 days after onset.
    The 1982 season observations by LGL and Greeneridge (1986) involved 
a single passage of an icebreaker with both ice-based and aerial 
measurements on June 28, 1982. Four groups of narwhals (n = 9 to 10, 7, 
7, and 6) responded when the ship was 4 mi (6.4 km) away (received 
levels of approximately 100 dB in the 150- to 1,150-Hz band). At a 
later point, observers sighted belugas moving away from the source at 
more than 12.4 mi (20 km; received levels of approximately 90 dB in the 
150- to 1,150-Hz band). The total number of animals observed fleeing 
was about 300, suggesting approximately 100 independent groups (of 
three individuals each). No whales were sighted the following day, but 
some were sighted on June 30, with ship noise audible at spectrum 
levels of approximately 55 dB/Hz (up to 4 kHz).
    Observations during 1983 (LGL and Greeneridge, 1986) involved two 
icebreaking ships with aerial survey and ice-based observations during 
seven sampling periods. Narwhals and belugas generally reacted at 
received levels ranging from 101 to 121 dB in the 20- to 1,000-Hz band 
and at a distance of up to 40.4 mi (65 km). Large numbers (100s) of 
beluga whales moved out of the area at higher received levels. As noise 
levels from icebreaking operations diminished, a total of 45 narwhals 
returned to the area and engaged in diving and foraging behavior. 
During the final sampling period, following an 8-h quiet interval, no 
reactions were seen from 28 narwhals and 17 belugas (at received levels 
ranging up to 115 dB).
    The final season (1984) reported in LGL and Greeneridge (1986) 
involved aerial surveys before, during, and after the passage of two 
icebreaking ships. During operations, no belugas and few narwhals were 
observed in an area approximately 16.8 mi (27 km) ahead of the vessels, 
and all whales sighted over 12.4-50 mi (20-80 km) from the ships were 
swimming strongly away. Additional observations confirmed the spatial 
extent of avoidance reactions to this sound source in this context.
    Buckstaff (2004) reported elevated dolphin whistle rates with 
received levels from oncoming vessels in the 110 to 120 dB range in 
Sarasota Bay, Florida. These hearing thresholds were apparently lower 
than those reported by a researcher listening with towed hydrophones. 
Morisaka et al. (2005) compared whistles from three populations of 
Indo-Pacific bottlenose dolphins. One population was exposed to vessel 
noise with spectrum levels of approximately 85 dB/Hz in the 1- to 22-
kHz band (broadband received levels approximately 128 dB) as opposed to 
approximately 65 dB/Hz in the same band (broadband received levels 
approximately 108 dB) for the other two sites. Dolphin whistles in the 
noisier environment had lower fundamental frequencies and less 
frequency modulation, suggesting a shift in sound parameters as a 
result of increased ambient noise.
    Morton and Symonds (2002) used census data on killer whales in 
British Columbia to evaluate avoidance of non-pulse acoustic harassment 
devices (AHDs). Avoidance ranges were about 2.5 mi (4 km). Also, there 
was a dramatic reduction in the number of days ``resident'' killer 
whales were sighted during AHD-active periods compared to pre- and 
post-exposure periods and a nearby control site.
    Monteiro-Neto et al. (2004) studied avoidance responses of tucuxi 
(Sotalia fluviatilis) to Dukane[supreg] Netmark acoustic deterrent 
devices. In a total of 30 exposure trials, approximately five groups 
each demonstrated significant avoidance compared to 20 pinger off and 
55 no-pinger control trials over two quadrats of about 0.19 mi\2\ (0.5 
km\2\). Estimated exposure received levels were approximately 115 dB.
    Awbrey and Stewart (1983) played back semi-submersible drillship 
sounds (source level: 163 dB) to belugas in Alaska. They reported 
avoidance reactions at 984 and 4,921 ft (300 and 1,500 m) and approach 
by groups at a distance of 2.2 mi (3.5 km; received levels were 
approximately 110 to 145 dB over these ranges assuming a 15 log R 
transmission loss). Similarly, Richardson et al. (1990) played back 
drilling platform sounds (source level: 163 dB) to belugas in Alaska. 
They conducted aerial observations of eight individuals among 
approximately 100 spread over an area several hundred meters to several 
kilometers from the sound source and found no obvious reactions. 
Moderate changes in movement were noted for three groups swimming 
within 656 ft (200 m) of the sound projector.
    Two studies deal with issues related to changes in marine mammal 
vocal behavior as a function of variable background noise levels. Foote 
et al. (2004) found increases in the duration of killer whale calls 
over the period 1977 to 2003, during which time vessel traffic in Puget 
Sound, and particularly whale-watching boats around the animals, 
increased dramatically. Scheifele et al. (2005) demonstrated that 
belugas in the St. Lawrence River increased the levels of their 
vocalizations as a function of the background noise level (the 
``Lombard Effect'').
    Several researchers conducting laboratory experiments on hearing 
and the effects of non-pulse sounds on hearing in mid-frequency 
cetaceans

[[Page 68986]]

have reported concurrent behavioral responses. Nachtigall et al. (2003) 
reported that noise exposures up to 179 dB and 55-min duration affected 
the trained behaviors of a bottlenose dolphin participating in a TTS 
experiment. Finneran and Schlundt (2004) provided a detailed, 
comprehensive analysis of the behavioral responses of belugas and 
bottlenose dolphins to 1-s tones (received levels 160 to 202 dB) in the 
context of TTS experiments. Romano et al. (2004) investigated the 
physiological responses of a bottlenose dolphin and a beluga exposed to 
these tonal exposures and demonstrated a decrease in blood cortisol 
levels during a series of exposures between 130 and 201 dB. 
Collectively, the laboratory observations suggested the onset of a 
behavioral response at higher received levels than did field studies. 
The differences were likely related to the very different conditions 
and contextual variables between untrained, free-ranging individuals 
vs. laboratory subjects that were rewarded with food for tolerating 
noise exposure.
    Pinnipeds--Pinnipeds generally seem to be less responsive to 
exposure to industrial sound than most cetaceans. Pinniped responses to 
underwater sound from some types of industrial activities such as 
seismic exploration appear to be temporary and localized (Harris et 
al., 2001; Reiser et al., 2009).
    Blackwell et al. (2004) reported little or no reaction of ringed 
seals in response to pile-driving activities during construction of a 
man-made island in the Beaufort Sea. Ringed seals were observed 
swimming as close as 151 ft (46 m) from the island and may have been 
habituated to the sounds which were likely audible at distances < 9,842 
ft (3,000 m) underwater and 0.3 mi (0.5 km) in air. Moulton et al. 
(2003) reported that ringed seal densities on ice in the vicinity of a 
man-made island in the Beaufort Sea did not change significantly before 
and after construction and drilling activities.
    Southall et al. (2007) reviewed literature describing responses of 
pinnipeds to non-pulsed sound and reported that the limited data 
suggest exposures between approximately 90 and 140 dB generally do not 
appear to induce strong behavioral responses in pinnipeds exposed to 
non-pulse sounds in water; no data exist regarding exposures at higher 
levels. It is important to note that among these studies, there are 
some apparent differences in responses between field and laboratory 
conditions. In contrast to the mid-frequency odontocetes, captive 
pinnipeds responded more strongly at lower levels than did animals in 
the field. Again, contextual issues are the likely cause of this 
difference.
    Jacobs and Terhune (2002) observed harbor seal reactions to AHDs 
(source level in this study was 172 dB) deployed around aquaculture 
sites. Seals were generally unresponsive to sounds from the AHDs. 
During two specific events, individuals came within 141 and 144 ft (43 
and 44 m) of active AHDs and failed to demonstrate any measurable 
behavioral response; estimated received levels based on the measures 
given were approximately 120 to 130 dB.
    Costa et al. (2003) measured received noise levels from an Acoustic 
Thermometry of Ocean Climate (ATOC) program sound source off northern 
California using acoustic data loggers placed on translocated elephant 
seals. Subjects were captured on land, transported to sea, instrumented 
with archival acoustic tags, and released such that their transit would 
lead them near an active ATOC source (at 939-m depth; 75-Hz signal with 
37.5-Hz bandwidth; 195 dB maximum source level, ramped up from 165 dB 
over 20 min) on their return to a haul-out site. Received exposure 
levels of the ATOC source for experimental subjects averaged 128 dB 
(range 118 to 137) in the 60- to 90-Hz band. None of the instrumented 
animals terminated dives or radically altered behavior upon exposure, 
but some statistically significant changes in diving parameters were 
documented in nine individuals. Translocated northern elephant seals 
exposed to this particular non-pulse source began to demonstrate subtle 
behavioral changes at exposure to received levels of approximately 120 
to 140 dB.
    Kastelein et al. (2006) exposed nine captive harbor seals in an 
approximately 82 x 98 ft (25 x 30 m) enclosure to non-pulse sounds used 
in underwater data communication systems (similar to acoustic modems). 
Test signals were frequency modulated tones, sweeps, and bands of noise 
with fundamental frequencies between 8 and 16 kHz; 128 to 130 [ 3] dB source levels; 1-to 2-s duration [60-80 percent duty 
cycle]; or 100 percent duty cycle. They recorded seal positions and the 
mean number of individual surfacing behaviors during control periods 
(no exposure), before exposure, and in 15-min experimental sessions (n 
= 7 exposures for each sound type). Seals generally swam away from each 
source at received levels of approximately 107 dB, avoiding it by 
approximately 16 ft (5 m), although they did not haul out of the water 
or change surfacing behavior. Seal reactions did not appear to wane 
over repeated exposure (i.e., there was no obvious habituation), and 
the colony of seals generally returned to baseline conditions following 
exposure. The seals were not reinforced with food for remaining in the 
sound field.
    Potential effects to pinnipeds from aircraft activity could involve 
both acoustic and non-acoustic effects. It is uncertain if the seals 
react to the sound of the helicopter or to its physical presence flying 
overhead. Typical reactions of hauled out pinnipeds to aircraft that 
have been observed include looking up at the aircraft, moving on the 
ice or land, entering a breathing hole or crack in the ice, or entering 
the water. Ice seals hauled out on the ice have been observed diving 
into the water when approached by a low-flying aircraft or helicopter 
(Burns and Harbo, 1972, cited in Richardson et al., 1995a; Burns and 
Frost, 1979, cited in Richardson et al., 1995a). Richardson et al. 
(1995a) note that responses can vary based on differences in aircraft 
type, altitude, and flight pattern. Additionally, a study conducted by 
Born et al. (1999) found that wind chill was also a factor in level of 
response of ringed seals hauled out on ice, as well as time of day and 
relative wind direction.
    Blackwell et al. (2004a) observed 12 ringed seals during low-
altitude overflights of a Bell 212 helicopter at Northstar in June and 
July 2000 (9 observations took place concurrent with pipe-driving 
activities). One seal showed no reaction to the aircraft while the 
remaining 11 (92%) reacted, either by looking at the helicopter (n=10) 
or by departing from their basking site (n=1). Blackwell et al. (2004a) 
concluded that none of the reactions to helicopters were strong or long 
lasting, and that seals near Northstar in June and July 2000 probably 
had habituated to industrial sounds and visible activities that had 
occurred often during the preceding winter and spring. There have been 
few systematic studies of pinniped reactions to aircraft overflights, 
and most of the available data concern pinnipeds hauled out on land or 
ice rather than pinnipeds in the water (Richardson et al., 1995a; Born 
et al., 1999).
    Born et al. (1999) determined that 49% of ringed seals escaped 
(i.e., left the ice) as a response to a helicopter flying at 492 ft 
(150 m) altitude. Seals entered the water when the helicopter was 4,101 
ft (1,250 m) away if the seal was in front of the helicopter and at 
1,640 ft (500 m) away if the seal was to the side of the helicopter. 
The authors noted that more seals reacted to helicopters than to fixed-
wing aircraft. The study concluded that the risk of scaring ringed

[[Page 68987]]

seals by small-type helicopters could be substantially reduced if they 
do not approach closer than 4,921 ft (1,500 m).
    Spotted seals hauled out on land in summer are unusually sensitive 
to aircraft overflights compared to other species. They often rush into 
the water when an aircraft flies by at altitudes up to 984-2,461 ft 
(300-750 m). They occasionally react to aircraft flying as high as 
4,495 ft (1,370 m) and at lateral distances as far as 1.2 mi (2 km) or 
more (Frost and Lowry, 1990; Rugh et al., 1997).
(4) Hearing Impairment and Other Physiological Effects
    Temporary or permanent hearing impairment is a possibility when 
marine mammals are exposed to very strong sounds. Non-auditory 
physiological effects might also occur in marine mammals exposed to 
strong underwater sound. Possible types of non-auditory physiological 
effects or injuries that theoretically might occur in mammals close to 
a strong sound source include stress, neurological effects, bubble 
formation, and other types of organ or tissue damage. It is possible 
that some marine mammal species (i.e., beaked whales) may be especially 
susceptible to injury and/or stranding when exposed to strong pulsed 
sounds. However, as discussed later in this document, there is no 
definitive evidence that any of these effects occur even for marine 
mammals in close proximity to industrial sound sources, and beaked 
whales do not occur in the proposed activity area. Additional 
information regarding the possibilities of TTS, permanent threshold 
shift (PTS), and non-auditory physiological effects, such as stress, is 
discussed for both exploratory drilling activities and ZVSP surveys in 
the next subsection (``Potential Effects from ZVSP Activities'').

Potential Effects From ZVSP Activities

(1) Tolerance
    Numerous studies have shown that pulsed sounds from airguns are 
often readily detectable in the water at distances of many kilometers. 
Weir (2008) observed marine mammal responses to seismic pulses from a 
24 airgun array firing a total volume of either 5,085 in\3\ or 3,147 
in\3\ in Angolan waters between August 2004 and May 2005. Weir recorded 
a total of 207 sightings of humpback whales (n = 66), sperm whales (n = 
124), and Atlantic spotted dolphins (n = 17) and reported that there 
were no significant differences in encounter rates (sightings/hr) for 
humpback and sperm whales according to the airgun array's operational 
status (i.e., active versus silent). For additional information on 
tolerance of marine mammals to anthropogenic sound, see the previous 
subsection in this document (``Potential Effects from Exploratory 
Drilling Activities'').
(2) Masking
    As stated earlier in this document, masking is the obscuring of 
sounds of interest by other sounds, often at similar frequencies. For 
full details about masking, see the previous subsection in this 
document (``Potential Effects from Exploratory Drilling Activities''). 
Some additional information regarding pulsed sounds is provided here.
    There is evidence of some marine mammal species continuing to call 
in the presence of industrial activity. McDonald et al. (1995) heard 
blue and fin whale calls between seismic pulses in the Pacific. 
Although there has been one report that sperm whales cease calling when 
exposed to pulses from a very distant seismic ship (Bowles et al., 
1994), a more recent study reported that sperm whales off northern 
Norway continued calling in the presence of seismic pulses (Madsen et 
al., 2002). Similar results were also reported during work in the Gulf 
of Mexico (Tyack et al., 2003). Bowhead whale calls are frequently 
detected in the presence of seismic pulses, although the numbers of 
calls detected may sometimes be reduced (Richardson et al., 1986; 
Greene et al., 1999; Blackwell et al., 2009a). Bowhead whales in the 
Beaufort Sea may decrease their call rates in response to seismic 
operations, although movement out of the area might also have 
contributed to the lower call detection rate (Blackwell et al., 
2009a,b). Additionally, there is increasing evidence that, at times, 
there is enough reverberation between airgun pulses such that detection 
range of calls may be significantly reduced. In contrast, Di Iorio and 
Clark (2009) found evidence of increased calling by blue whales during 
operations by a lower-energy seismic source, a sparker.
    There is little concern regarding masking due to the brief duration 
of these pulses and relatively longer silence between airgun shots (9-
12 seconds) near the sound source. However, at long distances (over 
tens of kilometers away) in deep water, due to multipath propagation 
and reverberation, the durations of airgun pulses can be ``stretched'' 
to seconds with long decays (Madsen et al., 2006; Clark and Gagnon, 
2006). Therefore it could affect communication signals used by low 
frequency mysticetes when they occur near the noise band and thus 
reduce the communication space of animals (e.g., Clark et al., 2009a,b) 
and cause increased stress levels (e.g., Foote et al., 2004; Holt et 
al., 2009). Nevertheless, the intensity of the noise is also greatly 
reduced at long distances. Therefore, masking effects are anticipated 
to be limited, especially in the case of odontocetes, given that they 
typically communicate at frequencies higher than those of the airguns.
(3) Behavioral Disturbance Reactions
    As was described in more detail in the previous sub-section 
(``Potential Effects of Exploratory Drilling Activities''), behavioral 
responses to sound are highly variable and context-specific. Summaries 
of observed reactions and studies are provided next.
    Baleen Whales--Baleen whale responses to pulsed sound (e.g., 
seismic airguns) have been studied more thoroughly than responses to 
continuous sound (e.g., drillships). Baleen whales generally tend to 
avoid operating airguns, but avoidance radii are quite variable. Whales 
are often reported to show no overt reactions to pulses from large 
arrays of airguns at distances beyond a few kilometers, even though the 
airgun pulses remain well above ambient noise levels out to much 
greater distances (Miller et al., 2005). However, baleen whales exposed 
to strong noise pulses often react by deviating from their normal 
migration route (Richardson et al., 1999). Migrating gray and bowhead 
whales were observed avoiding the sound source by displacing their 
migration route to varying degrees but within the natural boundaries of 
the migration corridors (Schick and Urban, 2000; Richardson et al., 
1999; Malme et al., 1983). Baleen whale responses to pulsed sound 
however may depend on the type of activity in which the whales are 
engaged. Some evidence suggests that feeding bowhead whales may be more 
tolerant of underwater sound than migrating bowheads (Miller et al., 
2005; Lyons et al., 2009; Christie et al., 2010).
    Results of studies of gray, bowhead, and humpback whales have 
determined that received levels of pulses in the 160-170 dB re 1 
[micro]Pa rms range seem to cause obvious avoidance behavior in a 
substantial fraction of the animals exposed. In many areas, seismic 
pulses from large arrays of airguns diminish to those levels at 
distances ranging from 2.8-9 mi (4.5-14.5 km) from the source. For the 
much smaller airgun array used during the ZVSP survey (total discharge 
volume of 760 in\3\), distances to received levels in the 170-160 dB re 
1 [mu]Pa rms range are estimated to be 1.44-

[[Page 68988]]

2.28 mi (2.31-3.67 km). Baleen whales within those distances may show 
avoidance or other strong disturbance reactions to the airgun array. 
Subtle behavioral changes sometimes become evident at somewhat lower 
received levels, and recent studies have shown that some species of 
baleen whales, notably bowhead and humpback whales, at times show 
strong avoidance at received levels lower than 160-170 dB re 1 [mu]Pa 
rms. Bowhead whales migrating west across the Alaskan Beaufort Sea in 
autumn, in particular, are unusually responsive, with avoidance 
occurring out to distances of 12.4-18.6 mi (20-30 km) from a medium-
sized airgun source (Miller et al., 1999; Richardson et al., 1999). 
However, more recent research on bowhead whales (Miller et al., 2005) 
corroborates earlier evidence that, during the summer feeding season, 
bowheads are not as sensitive to seismic sources. In summer, bowheads 
typically begin to show avoidance reactions at a received level of 
about 160-170 dB re 1 [micro]Pa rms (Richardson et al., 1986; Ljungblad 
et al., 1988; Miller et al., 2005).
    Malme et al. (1986, 1988) studied the responses of feeding eastern 
gray whales to pulses from a single 100 in\3\ airgun off St. Lawrence 
Island in the northern Bering Sea. They estimated, based on small 
sample sizes, that 50% of feeding gray whales ceased feeding at an 
average received pressure level of 173 dB re 1 [micro]Pa on an 
(approximate) rms basis, and that 10% of feeding whales interrupted 
feeding at received levels of 163 dB. Those findings were generally 
consistent with the results of experiments conducted on larger numbers 
of gray whales that were migrating along the California coast and on 
observations of the distribution of feeding Western Pacific gray whales 
off Sakhalin Island, Russia, during a seismic survey (Yazvenko et al., 
2007). Data on short-term reactions (or lack of reactions) of cetaceans 
to impulsive noises do not necessarily provide information about long-
term effects. While it is not certain whether impulsive noises affect 
reproductive rate or distribution and habitat use in subsequent days or 
years, certain species have continued to use areas ensonified by 
airguns and have continued to increase in number despite successive 
years of anthropogenic activity in the area. Gray whales continued to 
migrate annually along the west coast of North America despite 
intermittent seismic exploration and much ship traffic in that area for 
decades (Appendix A in Malme et al., 1984). Bowhead whales continued to 
travel to the eastern Beaufort Sea each summer despite seismic 
exploration in their summer and autumn range for many years (Richardson 
et al., 1987). Populations of both gray whales and bowhead whales grew 
substantially during this time. Bowhead whales have increased by 
approximately 3.4% per year for the last 10 years in the Beaufort Sea 
(Allen and Angliss, 2011). In any event, the brief exposures to sound 
pulses from the proposed airgun source (the airguns will only be fired 
for a period of 10-14 hours for each of the two wells) are highly 
unlikely to result in prolonged effects.
    Toothed Whales--Few systematic data are available describing 
reactions of toothed whales to noise pulses. Few studies similar to the 
more extensive baleen whale/seismic pulse work summarized earlier in 
this document have been reported for toothed whales. However, 
systematic work on sperm whales is underway (Tyack et al., 2003), and 
there is an increasing amount of information about responses of various 
odontocetes to seismic surveys based on monitoring studies (e.g., 
Stone, 2003; Smultea et al., 2004; Moulton and Miller, 2005).
    Seismic operators and marine mammal observers sometimes see 
dolphins and other small toothed whales near operating airgun arrays, 
but, in general, there seems to be a tendency for most delphinids to 
show some limited avoidance of seismic vessels operating large airgun 
systems. However, some dolphins seem to be attracted to the seismic 
vessel and floats, and some ride the bow wave of the seismic vessel 
even when large arrays of airguns are firing. Nonetheless, there have 
been indications that small toothed whales sometimes move away or 
maintain a somewhat greater distance from the vessel when a large array 
of airguns is operating than when it is silent (e.g., Goold, 1996a,b,c; 
Calambokidis and Osmek, 1998; Stone, 2003). The beluga may be a species 
that (at least at times) shows long-distance avoidance of seismic 
vessels. Aerial surveys during seismic operations in the southeastern 
Beaufort Sea recorded much lower sighting rates of beluga whales within 
6.2-12.4 mi (10-20 km) of an active seismic vessel. These results were 
consistent with the low number of beluga sightings reported by 
observers aboard the seismic vessel, suggesting that some belugas might 
be avoiding the seismic operations at distances of 6.2-12.4 mi (10-20 
km) (Miller et al., 2005).
    Captive bottlenose dolphins and (of more relevance in this project) 
beluga whales exhibit changes in behavior when exposed to strong pulsed 
sounds similar in duration to those typically used in seismic surveys 
(Finneran et al., 2002, 2005). However, the animals tolerated high 
received levels of sound (pk-pk level > 200 dB re 1 [mu]Pa) before 
exhibiting aversive behaviors.
    Reactions of toothed whales to large arrays of airguns are variable 
and, at least for delphinids, seem to be confined to a smaller radius 
than has been observed for mysticetes. However, based on the limited 
existing evidence, belugas should not be grouped with delphinids in the 
``less responsive'' category.
    Pinnipeds--Pinnipeds are not likely to show a strong avoidance 
reaction to the airgun sources proposed for use. Visual monitoring from 
seismic vessels has shown only slight (if any) avoidance of airguns by 
pinnipeds and only slight (if any) changes in behavior. Ringed seals 
frequently do not avoid the area within a few hundred meters of 
operating airgun arrays (Harris et al., 2001; Moulton and Lawson, 2002; 
Miller et al., 2005). Monitoring work in the Alaskan Beaufort Sea 
during 1996-2001 provided considerable information regarding the 
behavior of seals exposed to seismic pulses (Harris et al., 2001; 
Moulton and Lawson, 2002). These seismic projects usually involved 
arrays of 6 to 16 airguns with total volumes of 560 to 1,500 in\3\. The 
combined results suggest that some seals avoid the immediate area 
around seismic vessels. In most survey years, ringed seal sightings 
tended to be farther away from the seismic vessel when the airguns were 
operating than when they were not (Moulton and Lawson, 2002). However, 
these avoidance movements were relatively small, on the order of 328 ft 
(100 m) to a few hundreds of meters, and many seals remained within 
328-656 ft (100-200 m) of the trackline as the operating airgun array 
passed by. Seal sighting rates at the water surface were lower during 
airgun array operations than during no-airgun periods in each survey 
year except 1997. Similarly, seals are often very tolerant of pulsed 
sounds from seal-scaring devices (Mate and Harvey, 1987; Jefferson and 
Curry, 1994; Richardson et al., 1995a). However, initial telemetry work 
suggests that avoidance and other behavioral reactions by two other 
species of seals to small airgun sources may at times be stronger than 
evident to date from visual studies of pinniped reactions to airguns 
(Thompson et al., 1998). Even if reactions of the species occurring in 
the present study area are as strong as those evident in the telemetry 
study, reactions are expected to be confined to relatively small

[[Page 68989]]

distances and durations, with no long-term effects on pinniped 
individuals or populations. Additionally, the airguns are only proposed 
to be used for a short time during the exploration drilling program 
(approximately 10-14 hours for each well, for a total of 20-28 hours 
over the entire open-water season, which lasts for approximately 4 
months).
(4) Hearing Impairment and Other Physiological Effects
    TTS--TTS is the mildest form of hearing impairment that can occur 
during exposure to a strong sound (Kryter, 1985). While experiencing 
TTS, the hearing threshold rises, and a sound must be stronger in order 
to be heard. At least in terrestrial mammals, TTS can last from minutes 
or hours to (in cases of strong TTS) days, can be limited to a 
particular frequency range, and can be in varying degrees (i.e., a loss 
of a certain number of dBs of sensitivity). For sound exposures at or 
somewhat above the TTS threshold, hearing sensitivity in both 
terrestrial and marine mammals recovers rapidly after exposure to the 
noise ends. Few data on sound levels and durations necessary to elicit 
mild TTS have been obtained for marine mammals, and none of the 
published data concern TTS elicited by exposure to multiple pulses of 
sound.
    Marine mammal hearing plays a critical role in communication with 
conspecifics and in interpretation of environmental cues for purposes 
such as predator avoidance and prey capture. Depending on the degree 
(elevation of threshold in dB), duration (i.e., recovery time), and 
frequency range of TTS and the context in which it is experienced, TTS 
can have effects on marine mammals ranging from discountable to 
serious. For example, a marine mammal may be able to readily compensate 
for a brief, relatively small amount of TTS in a non-critical frequency 
range that takes place during a time when the animal is traveling 
through the open ocean, where ambient noise is lower and there are not 
as many competing sounds present. Alternatively, a larger amount and 
longer duration of TTS sustained during a time when communication is 
critical for successful mother/calf interactions could have more 
serious impacts if it were in the same frequency band as the necessary 
vocalizations and of a severity that it impeded communication. The fact 
that animals exposed to levels and durations of sound that would be 
expected to result in this physiological response would also be 
expected to have behavioral responses of a comparatively more severe or 
sustained nature is also notable and potentially of more importance 
than the simple existence of a TTS.
    Researchers have derived TTS information for odontocetes from 
studies on the bottlenose dolphin and beluga. For the one harbor 
porpoise tested, the received level of airgun sound that elicited onset 
of TTS was lower (Lucke et al., 2009). If these results from a single 
animal are representative, it is inappropriate to assume that onset of 
TTS occurs at similar received levels in all odontocetes (cf. Southall 
et al., 2007). Some cetaceans apparently can incur TTS at considerably 
lower sound exposures than are necessary to elicit TTS in the beluga or 
bottlenose dolphin.
    For baleen whales, there are no data, direct or indirect, on levels 
or properties of sound that are required to induce TTS. The frequencies 
to which baleen whales are most sensitive are assumed to be lower than 
those to which odontocetes are most sensitive, and natural background 
noise levels at those low frequencies tend to be higher. As a result, 
auditory thresholds of baleen whales within their frequency band of 
best hearing are believed to be higher (less sensitive) than are those 
of odontocetes at their best frequencies (Clark and Ellison, 2004), 
meaning that baleen whales require sounds to be louder (i.e., higher dB 
levels) than odontocetes in the frequency ranges at which each group 
hears the best. From this, it is suspected that received levels causing 
TTS onset may also be higher in baleen whales (Southall et al., 2007). 
Since current NMFS practice assumes the same thresholds for the onset 
of hearing impairment in both odontocetes and mysticetes, NMFS' onset 
of TTS threshold is likely conservative for mysticetes. For this 
proposed activity, Shell expects no cases of TTS given the strong 
likelihood that baleen whales would avoid the airguns before being 
exposed to levels high enough for TTS to occur. The source levels of 
the drillship are far lower than those of the airguns.
    In pinnipeds, TTS thresholds associated with exposure to brief 
pulses (single or multiple) of underwater sound have not been measured. 
However, systematic TTS studies on captive pinnipeds have been 
conducted (Bowles et al., 1999; Kastak et al., 1999, 2005, 2007; 
Schusterman et al., 2000; Finneran et al., 2003; Southall et al., 
2007). Initial evidence from more prolonged (non-pulse) exposures 
suggested that some pinnipeds (harbor seals in particular) incur TTS at 
somewhat lower received levels than do small odontocetes exposed for 
similar durations (Kastak et al., 1999, 2005; Ketten et al., 2001; cf. 
Au et al., 2000). The TTS threshold for pulsed sounds has been 
indirectly estimated as being a sound exposure level (SEL) of 
approximately 171 dB re 1 [mu]Pa\2\[middot]s (Southall et al., 2007) 
which would be equivalent to a single pulse with a received level of 
approximately 181 to 186 dB re 1 [mu]Pa (rms), or a series of pulses 
for which the highest rms values are a few dB lower. Corresponding 
values for California sea lions and northern elephant seals are likely 
to be higher (Kastak et al., 2005). For harbor seal, which is closely 
related to the ringed seal, TTS onset apparently occurs at somewhat 
lower received energy levels than for odonotocetes. The sound level 
necessary to cause TTS in pinnipeds depends on exposure duration, as in 
other mammals; with longer exposure, the level necessary to elicit TTS 
is reduced (Schusterman et al., 2000; Kastak et al., 2005, 2007). For 
very short exposures (e.g., to a single sound pulse), the level 
necessary to cause TTS is very high (Finneran et al., 2003). For 
pinnipeds exposed to in-air sounds, auditory fatigue has been measured 
in response to single pulses and to non-pulse noise (Southall et al., 
2007), although high exposure levels were required to induce TTS-onset 
(SEL: 129 dB re: 20 [mu]Pa\2\[middot]s; Bowles et al., unpub. data).
    NMFS has established acoustic thresholds that identify the received 
sound levels above which hearing impairment or other injury could 
potentially occur, which are 180 and 190 dB re 1 [mu]Pa (rms) for 
cetaceans and pinnipeds, respectively (NMFS 1995, 2000). The 
established 180- and 190-dB re 1 [mu]Pa (rms) criteria are the received 
levels above which, in the view of a panel of bioacoustics specialists 
convened by NMFS before additional TTS measurements for marine mammals 
became available, one could not be certain that there would be no 
injurious effects, auditory or otherwise, to marine mammals. TTS is 
considered by NMFS to be a type of Level B (non-injurious) harassment. 
The 180- and 190-dB levels are shutdown criteria applicable to 
cetaceans and pinnipeds, respectively, as specified by NMFS (2000) and 
are used to establish exclusion zones (EZs), as appropriate. 
Additionally, based on the summary provided here and the fact that 
modeling indicates the back-propagated source level for the Kulluk to 
be 185 dB re 1 [mu]Pa at 1 m (Greene, 1987) and for the Discoverer to 
be between 177 and 185 dB re 1 [mu]Pa at 1 m (Austin and Warner, 2010), 
TTS is not expected to occur in any marine mammal species

[[Page 68990]]

that may occur in the proposed drilling area since the source level 
will not reach levels thought to induce even mild TTS. While the source 
level of the airgun is higher than the 190-dB threshold level, an 
animal would have to be in very close proximity to be exposed to such 
levels. Additionally, the 180- and 190-dB radii for the airgun are 0.8 
mi (1.24 km) and 0.3 mi (524 m), respectively, from the source. Because 
of the short duration that the airguns will be used (no more than 20-28 
hours throughout the entire open-water season) and mitigation and 
monitoring measures described later in this document, hearing 
impairment is not anticipated.
    PTS--When PTS occurs, there is physical damage to the sound 
receptors in the ear. In some cases, there can be total or partial 
deafness, whereas in other cases, the animal has an impaired ability to 
hear sounds in specific frequency ranges (Kryter, 1985).
    There is no specific evidence that exposure to underwater 
industrial sound associated with oil exploration can cause PTS in any 
marine mammal (see Southall et al., 2007). However, given the 
possibility that mammals might incur TTS, there has been further 
speculation about the possibility that some individuals occurring very 
close to such activities might incur PTS (e.g., Richardson et al., 
1995, p. 372ff; Gedamke et al., 2008). Single or occasional occurrences 
of mild TTS are not indicative of permanent auditory damage in 
terrestrial mammals. Relationships between TTS and PTS thresholds have 
not been studied in marine mammals but are assumed to be similar to 
those in humans and other terrestrial mammals (Southall et al., 2007; 
Le Prell, in press). PTS might occur at a received sound level at least 
several decibels above that inducing mild TTS. Based on data from 
terrestrial mammals, a precautionary assumption is that the PTS 
threshold for impulse sounds (such as airgun pulses as received close 
to the source) is at least 6 dB higher than the TTS threshold on a 
peak-pressure basis and probably greater than 6 dB (Southall et al., 
2007).
    It is highly unlikely that marine mammals could receive sounds 
strong enough (and over a sufficient duration) to cause PTS during the 
proposed exploratory drilling program. As mentioned previously in this 
document, the source levels of the drillship are not considered strong 
enough to cause even slight TTS. Given the higher level of sound 
necessary to cause PTS, it is even less likely that PTS could occur. In 
fact, based on the modeled source levels for the drillship, the levels 
immediately adjacent to the drillship may not be sufficient to induce 
PTS, even if the animals remain in the immediate vicinity of the 
activity. The modeled source levels from the Kulluk and Discoverer 
suggest that marine mammals located immediately adjacent to a drillship 
would likely not be exposed to received sound levels of a magnitude 
strong enough to induce PTS, even if the animals remain in the 
immediate vicinity of the proposed activity location for a prolonged 
period of time. Because the source levels do not reach the threshold of 
190 dB currently used for pinnipeds and is at the 180 dB threshold 
currently used for cetaceans, it is highly unlikely that any type of 
hearing impairment, temporary or permanent, would occur as a result of 
the exploration drilling activities. Additionally, Southall et al. 
(2007) proposed that the thresholds for injury of marine mammals 
exposed to ``discrete'' noise events (either single or multiple 
exposures over a 24-hr period) are higher than the 180- and 190-dB re 1 
[mu]Pa (rms) in-water threshold currently used by NMFS. Table 1 in this 
document summarizes the SPL and SEL levels thought to cause auditory 
injury to cetaceans and pinnipeds in-water. For more information, 
please refer to Southall et al. (2007).

   Table 1--Proposed Injury Criteria for Cetaceans and Pinnipeds Exposed to ``Discrete'' Noise Events (Either
           Single Pulses, Multiple Pulses, or Non-Pulses Within a 24-hr Period; Southall et al., 2007)
----------------------------------------------------------------------------------------------------------------
                                            Single pulses           Multiple pulses             Non-pulses
----------------------------------------------------------------------------------------------------------------
                                             Low-frequency cetaceans
----------------------------------------------------------------------------------------------------------------
Sound pressure level.................  230 dB re 1 [mu]Pa       230 dB re 1 [mu]Pa       230 dB re 1 [mu]Pa
                                        (peak) (flat).           (peak) (flat).           (peak) (flat).
Sound exposure level.................  198 dB re 1 [mu]Pa       198 dB re 1 [mu]Pa       215 dB re 1 [mu]Pa
                                        \2\[middot]s (Mlf).      \2\[middot]s (Mlf).      \2\[middot]s (Mlf).
----------------------------------------------------------------------------------------------------------------
                                             Mid-frequency cetaceans
----------------------------------------------------------------------------------------------------------------
Sound pressure level.................  230 dB re 1 [mu]Pa       230 dB re 1 [mu]Pa       230 dB re 1 [mu]Pa
                                        (peak) (flat).           (peak) (flat).           (peak) (flat).
Sound exposure level.................  198 dB re 1 [mu]Pa       198 dB re 1 [mu]Pa       215 dB re 1 [mu]Pa
                                        \2\[middot]s (Mlf).      \2\[middot]s (Mlf).      \2\[middot]s (Mlf).
----------------------------------------------------------------------------------------------------------------
                                            High-frequency cetaceans
----------------------------------------------------------------------------------------------------------------
Sound pressure level.................  230 dB re 1 [mu]Pa       230 dB re 1 [mu]Pa       230 dB re 1 [mu]Pa
                                        (peak) (flat).           (peak) (flat).           (peak) (flat).
Sound exposure level.................  198 dB re 1 [mu]Pa       198 dB re 1 [mu]Pa       215 dB re 1 [mu]Pa
                                        \2\[middot]s (Mlf).      \2\[middot]s (Mlf).      \2\[middot]s (Mlf).
----------------------------------------------------------------------------------------------------------------
                                              Pinnipeds (in water)
----------------------------------------------------------------------------------------------------------------
Sound pressure level.................  218 dB re 1 [mu]Pa       218 dB re 1 [mu]Pa       218 dB re 1 [mu]Pa
                                        (peak) (flat).           (peak) (flat).           (peak) (flat).
Sound exposure level.................  186 dB re 1 [mu]Pa       186 dB re 1 [mu]Pa       203 dB re 1 [mu]Pa
                                        \2\[middot]s (Mpw).      \2\[middot]s (Mpw).      \2\[middot]s (Mpw).
----------------------------------------------------------------------------------------------------------------

    Non-auditory Physiological Effects--Non-auditory physiological 
effects or injuries that theoretically might occur in marine mammals 
exposed to strong underwater sound include stress, neurological 
effects, bubble formation, and other types of organ or tissue damage 
(Cox et al., 2006; Southall et al., 2007). Studies examining any such 
effects are limited. If any such effects do occur, they probably would 
be limited to unusual situations when animals might be exposed at close 
range for unusually long periods. It is doubtful that any single marine 
mammal would be exposed to strong sounds for sufficiently long that 
significant physiological stress would develop.
    Classic stress responses begin when an animal's central nervous 
system perceives a potential threat to its homeostasis. That perception 
triggers stress responses regardless of whether a stimulus actually 
threatens the animal; the mere perception of a threat is sufficient to 
trigger a stress response (Moberg, 2000; Sapolsky et al., 2005;

[[Page 68991]]

Seyle, 1950). Once an animal's central nervous system perceives a 
threat, it mounts a biological response or defense that consists of a 
combination of the four general biological defense responses: 
Behavioral responses; autonomic nervous system responses; 
neuroendocrine responses; or immune responses.
    In the case of many stressors, an animal's first and most 
economical (in terms of biotic costs) response is behavioral avoidance 
of the potential stressor or avoidance of continued exposure to a 
stressor. An animal's second line of defense to stressors involves the 
sympathetic part of the autonomic nervous system and the classical 
``fight or flight'' response, which includes the cardiovascular system, 
the gastrointestinal system, the exocrine glands, and the adrenal 
medulla to produce changes in heart rate, blood pressure, and 
gastrointestinal activity that humans commonly associate with 
``stress.'' These responses have a relatively short duration and may or 
may not have significant long-term effects on an animal's welfare.
    An animal's third line of defense to stressors involves its 
neuroendocrine or sympathetic nervous systems; the system that has 
received the most study has been the hypothalmus-pituitary-adrenal 
system (also known as the HPA axis in mammals or the hypothalamus-
pituitary-interrenal axis in fish and some reptiles). Unlike stress 
responses associated with the autonomic nervous system, virtually all 
neuroendocrine functions that are affected by stress--including immune 
competence, reproduction, metabolism, and behavior--are regulated by 
pituitary hormones. Stress-induced changes in the secretion of 
pituitary hormones have been implicated in failed reproduction (Moberg, 
1987; Rivier, 1995), altered metabolism (Elasser et al., 2000), reduced 
immune competence (Blecha, 2000), and behavioral disturbance. Increases 
in the circulation of glucocorticosteroids (cortisol, corticosterone, 
and aldosterone in marine mammals; see Romano et al., 2004) have been 
equated with stress for many years.
    The primary distinction between stress (which is adaptive and does 
not normally place an animal at risk) and distress is the biotic cost 
of the response. During a stress response, an animal uses glycogen 
stores that can be quickly replenished once the stress is alleviated. 
In such circumstances, the cost of the stress response would not pose a 
risk to the animal's welfare. However, when an animal does not have 
sufficient energy reserves to satisfy the energetic costs of a stress 
response, energy resources must be diverted from other biotic 
functions, which impair those functions that experience the diversion. 
For example, when mounting a stress response diverts energy away from 
growth in young animals, those animals may experience stunted growth. 
When mounting a stress response diverts energy from a fetus, an 
animal's reproductive success and fitness will suffer. In these cases, 
the animals will have entered a pre-pathological or pathological state 
which is called ``distress'' (sensu Seyle, 1950) or ``allostatic 
loading'' (sensu McEwen and Wingfield, 2003). This pathological state 
will last until the animal replenishes its biotic reserves sufficient 
to restore normal function. Note that these examples involved a long-
term (days or weeks) stress response exposure to stimuli.
    Relationships between these physiological mechanisms, animal 
behavior, and the costs of stress responses have also been documented 
fairly well through controlled experiment; because this physiology 
exists in every vertebrate that has been studied, it is not surprising 
that stress responses and their costs have been documented in both 
laboratory and free-living animals (for examples see, Holberton et al., 
1996; Hood et al., 1998; Jessop et al., 2003; Krausman et al., 2004; 
Lankford et al., 2005; Reneerkens et al., 2002; Thompson and Hamer, 
2000). Although no information has been collected on the physiological 
responses of marine mammals to anthropogenic sound exposure, studies of 
other marine animals and terrestrial animals would lead us to expect 
some marine mammals to experience physiological stress responses and, 
perhaps, physiological responses that would be classified as 
``distress'' upon exposure to anthropogenic sounds.
    For example, Jansen (1998) reported on the relationship between 
acoustic exposures and physiological responses that are indicative of 
stress responses in humans (e.g., elevated respiration and increased 
heart rates). Jones (1998) reported on reductions in human performance 
when faced with acute, repetitive exposures to acoustic disturbance. 
Trimper et al. (1998) reported on the physiological stress responses of 
osprey to low-level aircraft noise while Krausman et al. (2004) 
reported on the auditory and physiology stress responses of endangered 
Sonoran pronghorn to military overflights. Smith et al. (2004a, 2004b) 
identified noise-induced physiological transient stress responses in 
hearing-specialist fish (i.e., goldfish) that accompanied short- and 
long-term hearing losses. Welch and Welch (1970) reported physiological 
and behavioral stress responses that accompanied damage to the inner 
ears of fish and several mammals.
    Hearing is one of the primary senses marine mammals use to gather 
information about their environment and communicate with conspecifics. 
Although empirical information on the relationship between sensory 
impairment (TTS, PTS, and acoustic masking) on marine mammals remains 
limited, it seems reasonable to assume that reducing an animal's 
ability to gather information about its environment and to communicate 
with other members of its species would be stressful for animals that 
use hearing as their primary sensory mechanism. Therefore, we assume 
that acoustic exposures sufficient to trigger onset PTS or TTS would be 
accompanied by physiological stress responses because terrestrial 
animals exhibit those responses under similar conditions (NRC, 2003). 
More importantly, marine mammals might experience stress responses at 
received levels lower than those necessary to trigger onset TTS. Based 
on empirical studies of the time required to recover from stress 
responses (Moberg, 2000), NMFS also assumes that stress responses could 
persist beyond the time interval required for animals to recover from 
TTS and might result in pathological and pre-pathological states that 
would be as significant as behavioral responses to TTS. However, as 
stated previously in this document, the source levels of the drillships 
are not loud enough to induce PTS or likely even TTS.
    Resonance effects (Gentry, 2002) and direct noise-induced bubble 
formations (Crum et al., 2005) are implausible in the case of exposure 
to an impulsive broadband source like an airgun array. If seismic 
surveys disrupt diving patterns of deep-diving species, this might 
result in bubble formation and a form of the bends, as speculated to 
occur in beaked whales exposed to sonar. However, there is no specific 
evidence of this upon exposure to airgun pulses. Additionally, no 
beaked whale species occur in the proposed exploration drilling area.
    In general, very little is known about the potential for strong, 
anthropogenic underwater sounds to cause non-auditory physical effects 
in marine mammals. Such effects, if they occur at all, would presumably 
be limited to short distances and to activities that extend over a 
prolonged period. The available data do not allow identification of a 
specific exposure level above which non-auditory effects

[[Page 68992]]

can be expected (Southall et al., 2007) or any meaningful quantitative 
predictions of the numbers (if any) of marine mammals that might be 
affected in those ways. The low levels of continuous sound that will be 
produced by the drillship are not expected to cause such effects. 
Additionally, marine mammals that show behavioral avoidance of the 
proposed activities, including most baleen whales, some odontocetes 
(including belugas), and some pinnipeds, are especially unlikely to 
incur auditory impairment or other physical effects.

Stranding and Mortality

    Marine mammals close to underwater detonations of high explosives 
can be killed or severely injured, and the auditory organs are 
especially susceptible to injury (Ketten et al., 1993; Ketten, 1995). 
However, explosives are no longer used for marine waters for commercial 
seismic surveys; they have been replaced entirely by airguns or related 
non-explosive pulse generators. Underwater sound from drilling, support 
activities, and airgun arrays is less energetic and has slower rise 
times, and there is no proof that they can cause serious injury, death, 
or stranding, even in the case of large airgun arrays. However, the 
association of mass strandings of beaked whales with naval exercises 
involving mid-frequency active sonar, and, in one case, a Lamont-
Doherty Earth Observatory (L-DEO) seismic survey (Malakoff, 2002; Cox 
et al., 2006), has raised the possibility that beaked whales exposed to 
strong pulsed sounds may be especially susceptible to injury and/or 
behavioral reactions that can lead to stranding (e.g., Hildebrand, 
2005; Southall et al., 2007).
    Specific sound-related processes that lead to strandings and 
mortality are not well documented, but may include:
    (1) Swimming in avoidance of a sound into shallow water;
    (2) A change in behavior (such as a change in diving behavior) that 
might contribute to tissue damage, gas bubble formation, hypoxia, 
cardiac arrhythmia, hypertensive hemorrhage or other forms of trauma;
    (3) A physiological change, such as a vestibular response leading 
to a behavioral change or stress-induced hemorrhagic diathesis, leading 
in turn to tissue damage; and
    (4) Tissue damage directly from sound exposure, such as through 
acoustically-mediated bubble formation and growth or acoustic resonance 
of tissues.
    Some of these mechanisms are unlikely to apply in the case of 
impulse sounds. However, there are indications that gas-bubble disease 
(analogous to ``the bends''), induced in supersaturated tissue by a 
behavioral response to acoustic exposure, could be a pathologic 
mechanism for the strandings and mortality of some deep-diving 
cetaceans exposed to sonar. However, the evidence for this remains 
circumstantial and is associated with exposure to naval mid-frequency 
sonar, not seismic surveys or exploratory drilling programs (Cox et 
al., 2006; Southall et al., 2007).
    Both seismic pulses and continuous drillship sounds are quite 
different from mid-frequency sonar signals, and some mechanisms by 
which sonar sounds have been hypothesized to affect beaked whales are 
unlikely to apply to airgun pulses or drillships. Sounds produced by 
airgun arrays are broadband impulses with most of the energy below 1 
kHz, and the low-energy continuous sounds produced by drillships have 
most of the energy between 20 and 1,000 Hz. Additionally, the non-
impulsive, continuous sounds produced by the drillship proposed to be 
used by Shell do not have rapid rise times. Rise time is the 
fluctuation in sound levels of the source. The type of sound that would 
be produced during the proposed drilling program will be constant and 
will not exhibit any sudden fluctuations or changes. Typical military 
mid-frequency sonar emits non-impulse sounds at frequencies of 2-10 
kHz, generally with a relatively narrow bandwidth at any one time. A 
further difference between them is that naval exercises can involve 
sound sources on more than one vessel. Thus, it is not appropriate to 
assume that there is a direct connection between the effects of 
military sonar and oil and gas industry operations on marine mammals. 
However, evidence that sonar signals can, in special circumstances, 
lead (at least indirectly) to physical damage and mortality (e.g., 
Balcomb and Claridge, 2001; NOAA and USN, 2001; Jepson et al., 2003; 
Fern[aacute]ndez et al., 2004, 2005; Hildebrand, 2005; Cox et al., 
2006) suggests that caution is warranted when dealing with exposure of 
marine mammals to any high-intensity ``pulsed'' sound.
    There is no conclusive evidence of cetacean strandings or deaths at 
sea as a result of exposure to seismic surveys, but a few cases of 
strandings in the general area where a seismic survey was ongoing have 
led to speculation concerning a possible link between seismic surveys 
and strandings. Suggestions that there was a link between seismic 
surveys and strandings of humpback whales in Brazil (Engel et al., 
2004) were not well founded (IAGC, 2004; IWC, 2007). In September 2002, 
there was a stranding of two Cuvier's beaked whales in the Gulf of 
California, Mexico, when the L-DEO vessel R/V Maurice Ewing was 
operating a 20 airgun (8,490 in\3\) array in the general area. The link 
between the stranding and the seismic surveys was inconclusive and not 
based on any physical evidence (Hogarth, 2002; Yoder, 2002). 
Nonetheless, the Gulf of California incident, plus the beaked whale 
strandings near naval exercises involving use of mid-frequency sonar, 
suggests a need for caution in conducting seismic surveys in areas 
occupied by beaked whales until more is known about effects of seismic 
surveys on those species (Hildebrand, 2005). No injuries of beaked 
whales are anticipated during the proposed exploratory drilling program 
because none occur in the proposed area.

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 Beaufort 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

[[Page 68993]]

(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 
(large or very large oil spill) is highly unlikely and thus not 
reasonably expected to occur during the course of exploration drilling 
or ZVSP surveys. See Camden Bay 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, which 
was conditionally approved by the Department of the Interior, 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, Camden Bay, Beaufort 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; see also, Beaufort Sea Planning 
Area Environmental Assessment for Shell Offshore, Inc.'s 2012 Revised 
Outer Continental Shelf Lease Exploration Plan (August 2011).
    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; BOEMRE, 
2011). 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 Camden Bay, Beaufort 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 Beaufort 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 Camden Bay 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 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 is proposed in this IHA.

[[Page 68994]]

    Despite concluding that the risk of serious injury or mortality 
from an oil spill in this case is extremely remote, NMFS has 
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 below and will be addressed further in the 
Environmental Assessment.

Potential Effects of Oil on Cetaceans

    The specific effects an oil spill would have on bowhead, gray, or 
beluga whales or harbor porpoise are not well known. While mortality is 
unlikely, exposure to spilled oil could lead to skin irritation, baleen 
fouling (which might reduce feeding efficiency), respiratory distress 
from inhalation of hydrocarbon vapors, consumption of some contaminated 
prey items, and temporary displacement from contaminated feeding areas. 
Geraci and St. Aubin (1990) summarize effects of oil on marine mammals, 
and Bratton et al. (1993) provides a synthesis of knowledge of oil 
effects on bowhead whales. The number of whales that might be contacted 
by a spill would depend on the size, timing, and duration of the spill 
and where the oil is in relation to the whales. Whales may not avoid 
oil spills, and some have been observed feeding within oil slicks 
(Goodale et al., 1981). These topics are discussed in more detail next.
    In the case of an oil spill occurring during migration periods, 
disturbance of the migrating cetaceans from cleanup activities may have 
more of an impact than the oil itself. Human activity associated with 
cleanup efforts could deflect whales away from the path of the oil. 
However, noise created from cleanup activities likely will be short 
term and localized. In fact, whale avoidance of clean-up activities may 
benefit whales by displacing them from the oil spill area.
    There is no direct evidence that oil spills, including the much 
studied Santa Barbara Channel and Exxon Valdez spills, have caused any 
deaths of cetaceans (Geraci, 1990; Brownell, 1971; Harvey and Dahlheim, 
1994). It is suspected that some individually identified killer whales 
that disappeared from Prince William Sound during the time of the Exxon 
Valdez spill were casualties of that spill. However, no clear cause and 
effect relationship between the spill and the disappearance could be 
established (Dahlheim and Matkin, 1994). The AT-1 pod of transient 
killer whales that sometimes inhabits Prince William Sound has 
continued to decline after the Exxon Valdez oil spill (EVOS). Matkin et 
al. (2008) tracked the AB resident pod and the AT-1 transient group of 
killer whales from 1984 to 2005. The results of their photographic 
surveillance indicate a much higher than usual mortality rate for both 
populations the year following the spill (33% for AB Pod and 41% for 
AT-1 Group) and lower than average rates of increase in the 16 years 
after the spill (annual increase of about 1.6% for AB Pod compared to 
an annual increase of about 3.2% for other Alaska killer whale pods). 
In killer whale pods, mortality rates are usually higher for non-
reproductive animals and very low for reproductive animals and 
adolescents (Olesiuk et al., 1990, 2005; Matkin et al., 2005). No 
effects on humpback whales in Prince William Sound were evident after 
the EVOS (von Ziegesar et al., 1994). There was some temporary 
displacement of humpback whales out of Prince William Sound, but this 
could have been caused by oil contamination, boat and aircraft 
disturbance, displacement of food sources, or other causes.
    Migrating gray whales were apparently not greatly affected by the 
Santa Barbara spill of 1969. There appeared to be no relationship 
between the spill and mortality of marine mammals. The higher than 
usual counts of dead marine mammals recorded after the spill 
represented increased survey effort and therefore cannot be 
conclusively linked to the spill itself (Brownell, 1971; Geraci, 1990). 
The conclusion was that whales were either able to detect the oil and 
avoid it or were unaffected by it (Geraci, 1990).
(1) Oiling of External Surfaces
    Whales rely on a layer of blubber for insulation, so oil would have 
little if any effect on thermoregulation by whales. Effects of oiling 
on cetacean skin appear to be minor and of little significance to the 
animal's health (Geraci, 1990). Histological data and ultrastructural 
studies by Geraci and St. Aubin (1990) showed that exposures of skin to 
crude oil for up to 45 minutes in four species of toothed whales had no 
effect. They switched to gasoline and applied the sponge up to 75 
minutes. This produced transient damage to epidermal cells in whales. 
Subtle changes were evident only at the cell level. In each case, the 
skin damage healed within a week. They concluded that a cetacean's skin 
is an effective barrier to the noxious substances in petroleum. These 
substances normally damage skin by getting between cells and dissolving 
protective lipids. In cetacean skin, however, tight intercellular 
bridges, vital surface cells, and the extraordinary thickness of the 
epidermis impeded the damage. The authors could not detect a change in 
lipid concentration between and within cells after exposing skin from a 
white-sided dolphin to gasoline for 16 hours in vitro.
    Bratton et al. (1993) synthesized studies on the potential effects 
of contaminants on bowhead whales. They concluded that no published 
data proved oil fouling of the skin of any free-living whales, and 
concluded that bowhead whales contacting fresh or weathered petroleum 
are unlikely to suffer harm. Although oil is unlikely to adhere to 
smooth skin, it may stick to rough areas on the surface (Henk and 
Mullan, 1997). Haldiman et al. (1985) found the epidermal layer to be 
as much as seven to eight times thicker than that found on most whales. 
They also found that little or no crude oil adhered to preserved 
bowhead skin that was dipped into oil up to three times, as long as a 
water film stayed on the skin's surface. Oil adhered in small patches 
to the surface and vibrissae (stiff, hairlike structures), once it made 
enough contact with the skin. The amount of oil sticking to the 
surrounding skin and epidermal depression appeared to be in proportion 
to the number of exposures and the roughness of the skin's surface. It 
can be assumed that if oil contacted the eyes, effects would be similar 
to those observed in ringed seals; continued exposure of the eyes to 
oil could cause permanent damage (St. Aubin, 1990).
(2) Ingestion
    Whales could ingest oil if their food is contaminated, or oil could 
also be absorbed through the respiratory tract. Some of the ingested 
oil is voided in vomit or feces but some is absorbed and could cause 
toxic effects (Geraci, 1990). When returned to clean water, 
contaminated animals can depurate this internal oil (Engelhardt, 1978, 
1982). Oil ingestion can decrease food assimilation of prey eaten (St. 
Aubin, 1988). Cetaceans may swallow some oil-contaminated prey, but it 
likely would be only a small part of their food. It is not known if 
whales would leave a feeding area where prey was abundant following a 
spill. Some zooplankton eaten by bowheads and gray whales consume oil 
particles and bioaccumulation can result. Tissue studies by Geraci and 
St. Aubin (1990) revealed low levels of naphthalene in the livers and 
blubber of baleen whales. This result suggests that prey have low 
concentrations in their tissues, or that

[[Page 68995]]

baleen whales may be able to metabolize and excrete certain petroleum 
hydrocarbons. Whales exposed to an oil spill are unlikely to ingest 
enough oil to cause serious internal damage (Geraci and St. Aubin, 
1980, 1982) and this kind of damage has not been reported (Geraci, 
1990).
(3) Fouling of Baleen
    Baleen itself is not damaged by exposure to oil and is resistant to 
effects of oil (St. Aubin et al., 1984). Crude oil could coat the 
baleen and reduce filtration efficiency; however, effects may be 
temporary (Braithwaite, 1983; St. Aubin et al., 1984). If baleen is 
coated in oil for long periods, it could cause the animal to be unable 
to feed, which could lead to malnutrition or even death. Most of the 
oil that would coat the baleen is removed after 30 min, and less than 
5% would remain after 24 hr (Bratton et al., 1993). Effects of oiling 
of the baleen on feeding efficiency appear to be minor (Geraci, 1990). 
However, a study conducted by Lambertsen et al. (2005) concluded that 
their results highlight the uncertainty about how rapidly oil would 
depurate at the near zero temperatures in arctic waters and whether 
baleen function would be restored after oiling.
(4) Avoidance
    Some cetaceans can detect oil and sometimes avoid it, but others 
enter and swim through slicks without apparent effects (Geraci, 1990; 
Harvey and Dahlheim, 1994). Bottlenose dolphins apparently could detect 
and avoid slicks and mousse but did not avoid light sheens on the 
surface (Smultea and Wursig, 1995). After the Regal Sword spill in 
1979, various species of baleen and toothed whales were observed 
swimming and feeding in areas containing spilled oil southeast of Cape 
Cod, MA (Goodale et al., 1981). For months following EVOS, there were 
numerous observations of gray whales, harbor porpoises, Dall's 
porpoises, and killer whales swimming through light-to-heavy crude-oil 
sheens (Harvey and Dalheim, 1994, cited in Matkin et al., 2008). 
However, if some of the animals avoid the area because of the oil, then 
the effects of the oiling would be less severe on those individuals.
(5) Factors Affecting the Severity of Effects
    Effects of oil on whales in open water are likely to be minimal, 
but there could be effects on whales where both the oil and the whales 
are at least partly confined in leads or at ice edges (Geraci, 1990). 
In spring, bowhead and beluga whales migrate through leads in the ice. 
At this time, the migration can be concentrated in narrow corridors 
defined by the leads, thereby creating a greater risk to animals caught 
in the spring lead system should oil enter the leads. This situation 
would only occur if there were an oil spill late in the season and 
Shell could not complete cleanup efforts prior to ice covering the 
area. The oil would likely then be trapped in the ice until it began to 
thaw in the spring.
    In fall, the migration route of bowheads can be close to shore 
(Blackwell et al., 2009c). If fall migrants were moving through leads 
in the pack ice or were concentrated in nearshore waters, some bowhead 
whales might not be able to avoid oil slicks and could be subject to 
prolonged contamination. However, the autumn migration past Camden Bay 
extends over several weeks, and some of the whales travel along routes 
north of the area, thereby reducing the number of whales that could 
approach patches of spilled oil. Additionally, vessel activity 
associated with spill cleanup efforts may deflect whales traveling near 
Camden Bay farther offshore, thereby reducing the likelihood of contact 
with spilled oil. Also, during years when movements of oil and whales 
might be partially confined by ice, the bowhead migration corridor 
tends to be farther offshore (Treacy, 1997; LGL and Greeneridge, 1996a; 
Moore, 2000).
    Bowhead and beluga whales overwinter in the Bering Sea (mainly from 
November to March). In the summer, the majority of the bowhead whales 
are found in the Canadian Beaufort Sea, although some have recently 
been observed in the U.S. Beaufort and Chukchi Seas during the summer 
months (June to August). Data from the Barrow-based boat surveys in 
2009 (George and Sheffield, 2009) showed that bowheads were observed 
almost continuously in the waters near Barrow, including feeding groups 
in the Chukchi Sea at the beginning of July. The majority of belugas in 
the Beaufort stock migrate into the Beaufort Sea in April or May, 
although some whales may pass Point Barrow as early as late March and 
as late as July (Braham et al., 1984; Ljungblad et al., 1984; 
Richardson et al., 1995a). Therefore, a spill in summer would not be 
expected to have major impacts on these species. Additionally, while 
gray whales have commonly been sighted near Point Barrow, they are much 
less frequently found in the Camden Bay area. Therefore, an oil spill 
is not expected to have major impacts to gray whales.

Potential Effects of Oil on Pinnipeds

    Ringed, bearded, and spotted seals are present in open-water areas 
during summer and early autumn. Externally oiled phocid seals often 
survive and become clean, but heavily oiled seal pups and adults may 
die, depending on the extent of oiling and characteristics of the oil. 
Prolonged exposure could occur if fuel or crude oil was spilled in or 
reached nearshore waters, was spilled in a lead used by seals, or was 
spilled under the ice when seals have limited mobility (NMFS, 2000). 
Adult seals may suffer some temporary adverse effects, such as eye and 
skin irritation, with possible infection (MMS, 1996). Such effects may 
increase stress, which could contribute to the death of some 
individuals. Ringed seals may ingest oil-contaminated foods, but there 
is little evidence that oiled seals will ingest enough oil to cause 
lethal internal effects. There is a likelihood that newborn seal pups, 
if contacted by oil, would die from oiling through loss of insulation 
and resulting hypothermia. These potential effects are addressed in 
more detail in subsequent paragraphs.
    Reports of the effects of oil spills have shown that some mortality 
of seals may have occurred as a result of oil fouling; however, large 
scale mortality had not been observed prior to the EVOS (St. Aubin, 
1990). Effects of oil on marine mammals were not well studied at most 
spills because of lack of baseline data and/or the brevity of the post-
spill surveys. The largest documented impact of a spill, prior to EVOS, 
was on young seals in January in the Gulf of St. Lawrence (St. Aubin, 
1990). Brownell and Le Boeuf (1971) found no marked effects of oil from 
the Santa Barbara oil spill on California sea lions or on the mortality 
rates of newborn pups.
    Intensive and long-term studies were conducted after the EVOS in 
Alaska. There may have been a long-term decline of 36% in numbers of 
molting harbor seals at oiled haul-out sites in Prince William Sound 
following EVOS (Frost et al., 1994a). However, in a reanalysis of those 
data and additional years of surveys, along with an examination of 
assumptions and biases associated with the original data, Hoover-Miller 
et al. (2001) concluded that the EVOS effect had been overestimated. 
The decline in attendance at some oiled sites was more likely a 
continuation of the general decline in harbor seal abundance in Prince 
William Sound documented since 1984 (Frost et al., 1999) rather than a 
result of EVOS. The results from Hoover-Miller et al. (2001) indicate 
that the effects of EVOS were largely

[[Page 68996]]

indistinguishable from natural decline by 1992. However, while Frost et 
al. (2004) concluded that there was no evidence that seals were 
displaced from oiled sites, they did find that aerial counts indicated 
26% fewer pups were produced at oiled locations in 1989 than would have 
been expected without the oil spill. Harbor seal pup mortality at oiled 
beaches was 23% to 26%, which may have been higher than natural 
mortality, although no baseline data for pup mortality existed prior to 
EVOS (Frost et al., 1994a). There was no conclusive evidence of spill 
effects on Steller sea lions (Calkins et al., 1994). Oil did not 
persist on sea lions themselves (as it did on harbor seals), nor did it 
persist on sea lion haul-out sites and rookeries (Calkins et al., 
1994). Sea lion rookeries and haul out sites, unlike those used by 
harbor seals, have steep sides and are subject to high wave energy 
(Calkins et al., 1994).
(1) Oiling of External Surfaces
    Adult seals rely on a layer of blubber for insulation, and oiling 
of the external surface does not appear to have adverse 
thermoregulatory effects (Kooyman et al., 1976, 1977; St. Aubin, 1990). 
Contact with oil on the external surfaces can potentially cause 
increased stress and irritation of the eyes of ringed seals (Geraci and 
Smith, 1976; St. Aubin, 1990). These effects seemed to be temporary and 
reversible, but continued exposure of eyes to oil could cause permanent 
damage (St. Aubin, 1990). Corneal ulcers and abrasions, conjunctivitis, 
and swollen nictitating membranes were observed in captive ringed seals 
placed in crude oil-covered water (Geraci and Smith, 1976) and in seals 
in the Antarctic after an oil spill (Lillie, 1954).
    Newborn seal pups rely on their fur for insulation. Newborn ringed 
seal pups in lairs on the ice could be contaminated through contact 
with oiled mothers. There is the potential that newborn ringed seal 
pups that were contaminated with oil could die from hypothermia.
(2) Ingestion
    Marine mammals can ingest oil if their food is contaminated. Oil 
can also be absorbed through the respiratory tract (Geraci and Smith, 
1976; Engelhardt et al., 1977). Some of the ingested oil is voided in 
vomit or feces but some is absorbed and could cause toxic effects 
(Engelhardt, 1981). When returned to clean water, contaminated animals 
can depurate this internal oil (Engelhardt, 1978, 1982, 1985). In 
addition, seals exposed to an oil spill are unlikely to ingest enough 
oil to cause serious internal damage (Geraci and St. Aubin, 1980, 
1982).
(3) Avoidance and Behavioral Effects
    Although seals may have the capability to detect and avoid oil, 
they apparently do so only to a limited extent (St. Aubin, 1990). Seals 
may abandon the area of an oil spill because of human disturbance 
associated with cleanup efforts, but they are most likely to remain in 
the area of the spill. One notable behavioral reaction to oiling is 
that oiled seals are reluctant to enter the water, even when intense 
cleanup activities are conducted nearby (St. Aubin, 1990; Frost et al., 
1994b, 2004).
(4) Factors Affecting the Severity of Effects
    Seals that are under natural stress, such as lack of food or a 
heavy infestation by parasites, could potentially die because of the 
additional stress of oiling (Geraci and Smith, 1976; St. Aubin, 1990; 
Spraker et al., 1994). Female seals that are nursing young would be 
under natural stress, as would molting seals. In both cases, the seals 
would have reduced food stores and may be less resistant to effects of 
oil than seals that are not under some type of natural stress. Seals 
that are not under natural stress (e.g., fasting, molting) would be 
more likely to survive oiling.
    In general, seals do not exhibit large behavioral or physiological 
reactions to limited surface oiling or incidental exposure to 
contaminated food or vapors (St. Aubin, 1990; Williams et al., 1994). 
Effects could be severe if seals surface in heavy oil slicks in leads 
or if oil accumulates near haul-out sites (St. Aubin, 1990). An oil 
spill in open water is less likely to impact seals.
    The potential effects to marine mammals described in this section 
of the document do not take into consideration the proposed monitoring 
and mitigation measures described later in this document (see the 
``Proposed Mitigation'' and ``Proposed Monitoring and Reporting'' 
sections).

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). 
This section describes the potential impacts to marine mammal habitat 
from the specified activity. Because the marine mammals in the area 
feed on fish and/or invertebrates there is also information on the 
species typically preyed upon by the marine mammals in the area.

Common Marine Mammal Prey in the Project Area

    All eight of the marine mammal species that may occur in the 
proposed project area prey on either marine fish or invertebrates. The 
ringed seal feeds on fish and a variety of benthic species, including 
crabs and shrimp. Bearded seals feed mainly on benthic organisms, 
primarily crabs, shrimp, and clams. Spotted seals feed on pelagic and 
demersal fish, as well as shrimp and cephalopods. They are known to 
feed on a variety of fish including herring, capelin, sand lance, 
Arctic cod, saffron cod, and sculpins. Ribbon seals feed primarily on 
pelagic fish and invertebrates, such as shrimp, crabs, squid, octopus, 
cod, sculpin, pollack, and capelin. Juveniles feed mostly on krill and 
shrimp.
    Bowhead whales feed in the eastern Beaufort Sea during summer and 
early autumn but continue feeding to varying degrees while on their 
migration through the central and western Beaufort Sea in the late 
summer and fall (Richardson and Thomson [eds.], 2002). Aerial surveys 
in recent years have sighted bowhead whales feeding in Camden Bay on 
their westward migration through the Beaufort Sea. When feeding in 
relatively shallow areas, bowheads feed throughout the water column. 
However, feeding is concentrated at depths where zooplankton is 
concentrated (Wursig et al., 1984, 1989; Richardson [ed.], 1987; 
Griffiths et al., 2002). Lowry and Sheffield (2002) found that copepods 
and euphausiids were the most common prey found in stomach samples from 
bowhead whales harvested in the Kaktovik area from 1979 to 2000. Areas 
to the east of Barter Island (which is approximately 60 mi [96.6 km] 
east of Shell's proposed drill sites in Camden Bay) appear to be used 
regularly for feeding as bowhead whales migrate slowly westward across 
the Beaufort Sea (Thomson and Richardson, 1987; Richardson and Thomson 
[eds.], 2002). However, in some years, sizable groups of bowhead whales 
have been seen feeding as far west as the waters just east of Point 
Barrow (which is more than 250 mi [402 km] west of Shell's proposed 
drill sites in Camden Bay) near the Plover Islands (Braham et al., 
1984; Ljungblad et al., 1985; Landino et al., 1994). The situation in 
September-October 1997 was unusual in that bowheads fed widely across 
the Alaskan

[[Page 68997]]

Beaufort Sea, including higher numbers in the area east of Barrow than 
reported in any previous year (S. Treacy and D. Hansen, MMS, pers. 
comm.).
    Beluga whales feed on a variety of fish, shrimp, squid and octopus 
(Burns and Seaman, 1985). Very few beluga whales occur near Northstar; 
their main migration route is much further offshore. Like several of 
the other species in the area, harbor porpoise feed on demersal and 
benthic species, mainly schooling fish and cephalopods. Harbor porpoise 
are also not commonly found in Camden Bay.
    Gray whales are primarily bottom feeders, and benthic amphipods and 
isopods form the majority of their summer diet, at least in the main 
summering areas west of Alaska (Oliver et al., 1983; Oliver and 
Slattery, 1985). Farther south, gray whales have also been observed 
feeding around kelp beds, presumably on mysid crustaceans, and on 
pelagic prey such as small schooling fish and crab larvae (Hatler and 
Darling, 1974).
    Two kinds of fish inhabit marine waters in the study area: (1) True 
marine fish that spend all of their lives in salt water, and (2) 
anadromous species that reproduce in fresh water and spend parts of 
their life cycles in salt water.
    Most arctic marine fish species are small, benthic forms that do 
not feed high in the water column. The majority of these species are 
circumpolar and are found in habitats ranging from deep offshore water 
to water as shallow as 16.4-33 ft (5-10 m; Fechhelm et al., 1995). The 
most important pelagic species, and the only abundant pelagic species, 
is the Arctic cod. The Arctic cod is a major vector for the transfer of 
energy from lower to higher trophic levels (Bradstreet et al., 1986). 
In summer, Arctic cod can form very large schools in both nearshore and 
offshore waters (Craig et al., 1982; Bradstreet et al., 1986). 
Locations and areas frequented by large schools of Arctic cod cannot be 
predicted but can be almost anywhere. The Arctic cod is a major food 
source for beluga whales, ringed seals, and numerous species of 
seabirds (Frost and Lowry, 1984; Bradstreet et al., 1986).
    Anadromous Dolly Varden char and some species of whitefish winter 
in rivers and lakes, migrate to the sea in spring and summer, and 
return to fresh water in autumn. Anadromous fish form the basis of 
subsistence, commercial, and small regional sport fisheries. Dolly 
Varden char migrate to the sea from May through mid-June (Johnson, 
1980) and spend about 1.5-2.5 months there (Craig, 1989). They return 
to rivers beginning in late July or early August with the peak return 
migration occurring between mid-August and early September (Johnson, 
1980). At sea, most anadromous corregonids (whitefish) remain in 
nearshore waters within several kilometers of shore (Craig, 1984, 
1989). They are often termed ``amphidromous'' fish in that they make 
repeated annual migrations into marine waters to feed, returning each 
fall to overwinter in fresh water.
    Benthic organisms are defined as bottom dwelling creatures. 
Infaunal organisms are benthic organisms that live within the substrate 
and are often sedentary or sessile (bivalves, polychaetes). Epibenthic 
organisms live on or near the bottom surface sediments and are mobile 
(amphipods, isopods, mysids, and some polychaetes). Epifauna, which 
live attached to hard substrates, are rare in the Beaufort Sea because 
hard substrates are scarce there. A small community of epifauna, the 
Boulder Patch, occurs in Stefansson Sound.
    Many of the nearshore benthic marine invertebrates of the Arctic 
are circumpolar and are found over a wide range of water depths (Carey 
et al., 1975). Species identified include polychaetes (Spio filicornis, 
Chaetozone setosa, Eteone longa), bivalves (Cryrtodaria kurriana, 
Nucula tenuis, Liocyma fluctuosa), an isopod (Saduria entomon), and 
amphipods (Pontoporeia femorata, P. affinis).
    Nearshore benthic fauna have been studied in lagoons west of Camden 
Bay and near the mouth of the Colville River (Kinney et al., 1971, 
1972; Crane and Cooney, 1975). The waters of Simpson Lagoon, Harrison 
Bay, and the nearshore region support a number of infaunal species 
including crustaceans, mollusks, and polychaetes. In areas influenced 
by river discharge, seasonal changes in salinity can greatly influence 
the distribution and abundance of benthic organisms. Large fluctuations 
in salinity and temperature that occur over a very short time period, 
or on a seasonal basis, allow only very adaptable, opportunistic 
species to survive (Alexander et al., 1974). Since shorefast ice is 
present for many months, the distribution and abundance of most species 
depends on annual (or more frequent) recolonization from deeper 
offshore waters (Woodward Clyde Consultants, 1995). Due to ice 
scouring, particularly in water depths of less than 8 ft (2.4 m), 
infaunal communities tend to be patchily distributed. Diversity 
increases with water depth until the shear zone is reached at 49-82 ft 
(15-25 m; Carey, 1978). Biodiversity then declines due to ice gouging 
between the landfast ice and the polar pack ice (Woodward Clyde 
Consultants, 1995).

Potential Impacts From Seafloor Disturbance on Marine Mammal Habitat

    There is a possibility of some seafloor disturbance or temporary 
increased turbidity in the seabed sediments during anchoring and 
excavation of the mudline cellars (MLCs). The amount and duration of 
disturbed or turbid conditions will depend on sediment material and 
consolidation of specific activity.
    The Kulluk would be anchored using a 12-point anchor system held in 
place with 12, 15 metric ton Stevpris anchors, and the Discoverer would 
be stabilized and held in place with a system of eight 7,000 kg 
Stevpris anchors during operations. The anchors from either drilling 
vessel are designed to embed into the seafloor. Prior to setting, the 
anchors will penetrate the seafloor and drag two or three times their 
length. Both the anchor and anchor chain will disturb sediments and 
create an ``anchor scar'' which is a depression in the seafloor caused 
by the anchor embedding. The anchor scar is a depression with ridges of 
displaced sediment, and the area of disturbance will often be greater 
than the size of the anchor itself because the anchor is dragged along 
the seafloor until it takes hold and sets.
    For the Kulluk, each Stevpris anchor may impact an area of 2,928 
ft\2\ (272 m\2\), whereas each Stevpris anchor from the Discoverer may 
impact an area of 2,027 ft\2\ (188 m\2\) of the seafloor. Minimum 
impact estimates of the seafloor from each well or mooring with the 12 
anchors of the Kulluk is 35,136 ft\2\ (3,264 m\2\) or with the eight 
anchors of the Discoverer is 16,216 ft\2\ (1,507 m\2\). This estimate 
assumes that the anchors are set only once. Shell plans to pre-set 
anchors at each drill site for whichever drillship is used for 
drilling. Unless moved by an outside force such as sea current, anchors 
should only need to be set once per drill site. (Shell proposes to 
drill at two sites in Camden Bay during the 2012 open-water season.) 
Additionally, based on the vast size of the Beaufort Sea, the area of 
disturbance is not anticipated to adversely affect marine mammal use of 
the area.
    Once the drillship ends operation, the anchors will be retrieved. 
Over time, the anchor scars will be filled through natural movement of 
sediment. The duration of the scars depends upon the energy of the 
system, water depth, ice scour, and sediment type. Anchor scars were 
visible under low energy conditions in the North Sea for 5-10 years 
after retrieval. Scars typically do

[[Page 68998]]

not form or persist in sandy mud or sand sediments but may last for 9 
years in hard clays (Centaur Associates Inc., 1984). The surficial 
Holocene soils at the Sivulliq and Torpedo prospects consist primarily 
of soft to stiff silts and clays with low to medium plasticity. The 
fine sand present in contact with underlying silts and clays is 
variable, as the sand tends to infill old gouges. Local depositional 
processes will strongly affect the range of properties for Holocene 
soils. The energy regime plus possible effects of ice gouge in the 
Beaufort Sea suggest that anchor scars would be refilled faster than in 
the North Sea.
    Excavation of each MLC by the Kulluk will displace about 24,579 
ft\3\ (696 m\3\) of seafloor sediments and directly disturb 
approximately 452 ft\2\ (42m\2\) of seafloor. Excavation of each MLC by 
the Discoverer will displace about 17,128 ft\3\ (485 m\3\) of seafloor 
sediments and directly disturb approximately 314 ft\2\ (29 m\2\) of 
seafloor. The MLC excavation amounts range in volume because the MLC 
bits for the Kulluk and Discoverer differ in size and hence excavate 
different diameter MLCs. Material will be excavated from the MLCs using 
a large diameter drillbit. Pressurized air and water (no drilling mud 
used) will be used to assist in the removal of the excavated materials 
from the MLC. Some of the excavated sediments will be displaced to 
adjacent seafloor areas and some will be removed via the air lift 
system and discharged on the seafloor away from the MLC. These 
excavated materials will also have some indirect effects as they are 
deposited on the seafloor in the vicinity of the MLCs. Direct and 
indirect effects would include slight changes in seafloor relief and 
sediment consistency.
    Vessel mooring and MLC construction would result in increased 
suspended sediment in the water column that could result in lethal 
effects on some zooplankton (food source for baleen whales). However, 
compared to the overall population of zooplankton and the localized 
nature of effects, any mortality that may occur would not be considered 
significant. Due to fast regeneration periods of zooplankton, 
populations are expected to recover quickly.
    Impacts on fish resulting from suspended sediments would be 
dependent upon the life stage of the fish (e.g., eggs, larvae, 
juveniles, or adults), the concentration of the suspended sediments, 
the type of sediment, and the duration of exposure (IMG Golder, 2004). 
Eggs and larvae have been found to exhibit greater sensitivity to 
suspended sediments (Wilber and Clarke, 2001) and other stresses, which 
is thought to be related to their relative lack of motility (Auld and 
Schubel, 1978). Sedimentation could affect fish by causing egg 
morbidity of demersal fish feeding near or on the ocean floor (Wilber 
and Clarke, 2001). Surficial membranes are especially susceptible to 
abrasion (Cairns and Scheier, 1968). However, most of the abundant 
Beaufort Sea fish species with demersal eggs spawn under the ice in the 
winter well before MLC excavation would occur. Exposure of pelagic eggs 
would be much shorter as they move with ocean currents (Wilber and 
Clarke, 2001).
    Suspended sediments, resulting from vessel mooring and MLC 
excavation, are not expected to result in permanent damage to habitats 
used by the marine mammal species in the proposed project area or on 
the food sources that they utilize. Rather, NMFS considers that such 
impacts will be temporary in nature and concentrated in the areas 
directly surrounding vessel mooring and MLC excavation activities--
areas which are very small relative to the overall Beaufort Sea region.

Potential Impacts From Sound Generation

    With regard to fish as a prey source for odontocetes and seals, 
fish are known to hear and react to sounds and to use sound to 
communicate (Tavolga et al., 1981) and possibly avoid predators (Wilson 
and Dill, 2002). Experiments have shown that fish can sense both the 
strength and direction of sound (Hawkins, 1981). Primary factors 
determining whether a fish can sense a sound signal, and potentially 
react to it, are the frequency of the signal and the strength of the 
signal in relation to the natural background noise level.
    Fishes produce sounds that are associated with behaviors that 
include territoriality, mate search, courtship, and aggression. It has 
also been speculated that sound production may provide the means for 
long distance communication and communication under poor underwater 
visibility conditions (Zelick et al., 1999), although the fact that 
fish communicate at low-frequency sound levels where the masking 
effects of ambient noise are naturally highest suggests that very long 
distance communication would rarely be possible. Fishes have evolved a 
diversity of sound generating organs and acoustic signals of various 
temporal and spectral contents. Fish sounds vary in structure, 
depending on the mechanism used to produce them (Hawkins, 1993). 
Generally, fish sounds are predominantly composed of low frequencies 
(less than 3 kHz).
    Since objects in the water scatter sound, fish are able to detect 
these objects through monitoring the ambient noise. Therefore, fish are 
probably able to detect prey, predators,conspecifics, and physical 
features by listening to environmental sounds (Hawkins, 1981). There 
are two sensory systems that enable fish to monitor the vibration-based 
information of their surroundings. The two sensory systems, the inner 
ear and the lateral line, constitute the acoustico-lateralis system.
    Although the hearing sensitivities of very few fish species have 
been studied to date, it is becoming obvious that the intra- and inter-
specific variability is considerable (Coombs, 1981). Nedwell et al. 
(2004) compiled and published available fish audiogram information. A 
noninvasive electrophysiological recording method known as auditory 
brainstem response is now commonly used in the production of fish 
audiograms (Yan, 2004). Generally, most fish have their best hearing in 
the low-frequency range (i.e., less than 1 kHz). Even though some fish 
are able to detect sounds in the ultrasonic frequency range, the 
thresholds at these higher frequencies tend to be considerably higher 
than those at the lower end of the auditory frequency range.
    Literature relating to the impacts of sound on marine fish species 
can be divided into the following categories: (1) Pathological effects; 
(2) physiological effects; and (3) behavioral effects. Pathological 
effects include lethal and sub-lethal physical damage to fish; 
physiological effects include primary and secondary stress responses; 
and behavioral effects include changes in exhibited behaviors of fish. 
Behavioral changes might be a direct reaction to a detected sound or a 
result of the anthropogenic sound masking natural sounds that the fish 
normally detect and to which they respond. The three types of effects 
are often interrelated in complex ways. For example, some physiological 
and behavioral effects could potentially lead to the ultimate 
pathological effect of mortality. Hastings and Popper (2005) reviewed 
what is known about the effects of sound on fishes and identified 
studies needed to address areas of uncertainty relative to measurement 
of sound and the responses of fishes. Popper et al. (2003/2004) also 
published a paper that reviews the effects of anthropogenic sound on 
the behavior and physiology of fishes.
    Potential effects of exposure to continuous sound on marine fish 
include TTS, physical damage to the ear region, physiological stress 
responses, and behavioral responses such as startle

[[Page 68999]]

response, alarm response, avoidance, and perhaps lack of response due 
to masking of acoustic cues. Most of these effects appear to be either 
temporary or intermittent and therefore probably do not significantly 
impact the fish at a population level. The studies that resulted in 
physical damage to the fish ears used noise exposure levels and 
durations that were far more extreme than would be encountered under 
conditions similar to those expected during Shell's proposed 
exploratory drilling activities.
    The level of sound at which a fish will react or alter its behavior 
is usually well above the detection level. Fish have been found to 
react to sounds when the sound level increased to about 20 dB above the 
detection level of 120 dB (Ona, 1988); however, the response threshold 
can depend on the time of year and the fish's physiological condition 
(Engas et al., 1993). In general, fish react more strongly to pulses of 
sound rather than a continuous signal (Blaxter et al., 1981), such as 
the type of sound that will be produced by the drillship, and a quicker 
alarm response is elicited when the sound signal intensity rises 
rapidly compared to sound rising more slowly to the same level.
    Investigations of fish behavior in relation to vessel noise (Olsen 
et al., 1983; Ona, 1988; Ona and Godo, 1990) have shown that fish react 
when the sound from the engines and propeller exceeds a certain level. 
Avoidance reactions have been observed in fish such as cod and herring 
when vessels approached close enough that received sound levels are 110 
dB to 130 dB (Nakken, 1992; Olsen, 1979; Ona and Godo, 1990; Ona and 
Toresen, 1988). However, other researchers have found that fish such as 
polar cod, herring, and capeline are often attracted to vessels 
(apparently by the noise) and swim toward the vessel (Rostad et al., 
2006). Typical sound source levels of vessel noise in the audible range 
for fish are 150 dB to 170 dB (Richardson et al., 1995a). (Based on 
models, the 160 dB radius for the Discoverer would extend approximately 
33 ft [10 m] and the 160 dB radius for the Kulluk would extend 
approximately 180 ft [55 m]; therefore, fish would need to be in close 
proximity to the drillship for the noise to be audible). In calm 
weather, ambient noise levels in audible parts of the spectrum lie 
between 60 dB to 100 dB.
    Sound will also occur in the marine environment from the various 
support vessels. Reported source levels for vessels during ice 
management have ranged from 175 dB to 185 dB (Brewer et al., 1993, Hall 
et al., 1994). However, ice management or icebreaking activities are 
not expected to be necessary throughout the entire drilling season, so 
impacts from that activity would occur less frequently than sound from 
the drillship. Sound pressures generated by drilling vessels during 
active drilling operations have been measured during past exploration 
in the Beaufort and Chukchi seas. Sounds generated by drilling and ice 
management/icebreaking are generally low frequency and within the 
frequency range detectable by most fish.
    Shell also proposes to conduct seismic surveys with an airgun array 
for a short period of time during the drilling season (a total of 
approximately 20-28 hours over the course of the entire proposed 
drilling program). Airguns produce impulsive sounds as opposed to 
continuous sounds at the source. Short, sharp sounds can cause overt or 
subtle changes in fish behavior. Chapman and Hawkins (1969) tested the 
reactions of whiting (hake) in the field to an airgun. When the airgun 
was fired, the fish dove from 82 to 180 ft (25 to 55 m) depth and 
formed a compact layer. The whiting dove when received sound levels 
were higher than 178 dB re 1 [micro]Pa (Pearson et al., 1992).
    Pearson et al. (1992) conducted a controlled experiment to 
determine effects of strong noise pulses on several species of rockfish 
off the California coast. They used an airgun with a source level of 
223 dB re 1 [micro]Pa. They noted:
     Startle responses at received levels of 200-205 dB re 1 
[micro]Pa and above for two sensitive species, but not for two other 
species exposed to levels up to 207 dB;
     Alarm responses at 177-180 dB for the two sensitive 
species, and at 186 to 199 dB for other species;
     An overall threshold for the above behavioral response at 
about 180 dB;
     An extrapolated threshold of about 161 dB for subtle 
changes in the behavior of rockfish; and
     A return to pre-exposure behaviors within the 20-60 minute 
exposure period.
    In summary, fish often react to sounds, especially strong and/or 
intermittent sounds of low frequency. Sound pulses at received levels 
of 160 dB re 1 [micro]Pa may cause subtle changes in behavior. Pulses 
at levels of 180 dB may cause noticeable changes in behavior (Chapman 
and Hawkins, 1969; Pearson et al., 1992; Skalski et al., 1992). It also 
appears that fish often habituate to repeated strong sounds rather 
rapidly, on time scales of minutes to an hour. However, the habituation 
does not endure, and resumption of the strong sound source may again 
elicit disturbance responses from the same fish. Underwater sound 
levels from the drillship and other vessels produce sounds lower than 
the response threshold reported by Pearson et al. (1992), and are not 
likely to result in major effects to fish near the proposed drill 
sites.
    Based on a sound level of approximately 140 dB, there may be some 
avoidance by fish of the area near the drillship while drilling, around 
ice management vessels in transit and during ice management, and around 
other support and supply vessels when underway. Any reactions by fish 
to these sounds will last only minutes (Mitson and Knudsen, 2003; Ona 
et al., 2007) longer than the vessel is operating at that location or 
the drillship is drilling. Any potential reactions by fish would be 
limited to a relatively small area within about 0.21 mi (0.34 km) of 
the drillship during drilling (JASCO, 2007). Avoidance by some fish or 
fish species could occur within portions of this area. No important 
spawning habitats are known to occur at or near the drilling locations.
    Some of the fish species found in the Arctic are prey sources for 
odontocetes and pinnipeds. A reaction by fish to sounds produced by 
Shell's proposed operations would only be relevant to marine mammals if 
it caused concentrations of fish to vacate the area. Pressure changes 
of sufficient magnitude to cause that type of reaction would probably 
occur only very close to the sound source, if any would occur at all 
due to the low energy sounds produced by the majority of equipment 
proposed for use. Impacts on fish behavior are predicted to be 
inconsequential. Thus, feeding odontocetes and pinnipeds would not be 
adversely affected by this minimal loss or scattering, if any, of 
reduced prey abundance.
    Some mysticetes, including bowhead whales, feed on concentrations 
of zooplankton. Some feeding bowhead whales may occur in the Alaskan 
Beaufort Sea in July and August, and others feed intermittently during 
their westward migration in September and October (Richardson and 
Thomson [eds.], 2002; Lowry et al., 2004). Reactions of zooplankton to 
sound are, for the most part, not known. Their ability to move 
significant distances is limited or nil, depending on the type of 
zooplankton. Behavior of zooplankters is not expected to be affected by 
the exploratory drilling activities. These animals have exoskeletons 
and no air bladders. Many crustaceans can make sounds, and some 
crustacea and other

[[Page 69000]]

invertebrates have some type of sound receptor. A reaction by 
zooplankton to sounds produced by the exploratory drilling program 
would only be relevant to whales if it caused concentrations of 
zooplankton to scatter. Pressure changes of sufficient magnitude to 
cause that type of reaction would probably occur only very close to the 
sound source, if any would occur at all due to the low energy sounds 
produced by the drillship. Impacts on zooplankton behavior are 
predicted to be inconsequential. Thus, feeding mysticetes would not be 
adversely affected by this minimal loss or scattering, if any, of 
reduced zooplankton abundance.
    Aerial surveys in recent years have sighted bowhead whales feeding 
in Camden Bay on their westward migration through the Beaufort Sea. 
Individuals feeding in the Camden Bay area at the beginning of the 
migration (i.e., approximately late August or early September) are not 
expected to be impacted by Shell's proposed drilling program, primarily 
because of Shell's proposal to suspend operations and depart the area 
on August 25 and not return until the close of the Kaktovik and Nuiqsut 
(Cross Island) hunts, which typically ends around mid- to late 
September (see the ``Plan of Cooperation (POC)'' subsection later in 
this document for more details). If other individual bowheads stop to 
feed in the Camden Bay area after Shell resumes drilling operations in 
mid- to late September, they may potentially be exposed to sounds from 
the drillship or the airguns. However, injury to the bowhead whales is 
not anticipated, as the source level of the drillship is not loud 
enough to cause even mild TTS, as discussed earlier in this document, 
and mitigation measures are proposed to reduce even further the low 
risk of hearing impairment from the airguns. As mentioned earlier in 
this document, some bowhead whales have demonstrated avoidance behavior 
in areas of industrial sound (e.g., Richardson et al., 1999) and some 
have continued to feed even in the presence of industrial activities 
(Richardson, 2004). However, Camden Bay is not the only feeding 
location for bowhead whales in the Beaufort Sea. Also, as discussed 
previously, drilling operations are not expected to adversely affect 
bowhead whale prey species or preclude bowhead whales from obtaining 
sufficient food resources along their traditional migratory path.

Potential Impacts From Drill Cuttings

    Discharging drill cuttings or other liquid waste streams generated 
by the drilling vessel could potentially affect marine mammal habitat. 
Toxins could persist in the water column, which could have an impact on 
marine mammal prey species. However, despite a considerable amount of 
investment in research of exposures of marine mammals to 
organochlorines or other toxins, there have been no marine mammal 
deaths in the wild that can be conclusively linked to the direct 
exposure to such substances (O'Shea, 1999).
    For the Camden Bay proposed exploration drilling program, Shell has 
committed to not discharge various waste streams during routine 
drilling operations. Shell has agreed to not discharge any of the 
following liquid waste streams that are generated by the drilling 
vessel: treated sanitary waste (black water); domestic waste (gray 
water); bilge water; or ballast water. Shell will not discharge 
drilling mud or cuttings that are generated below the depth at which 
the 20-in. (51-cm) diameter casing is set in each well. The mud and 
cuttings collected will be transferred to an OSV then to the deck or 
waste barge. Either barge will hold collected mud, cuttings, and 
wastewater for transport and disposal at an approved and licensed 
onshore facility.
    Shell proposes that cuttings generated while drilling the MLC, the 
36- and 26-in. (91- and 66-cm) hole sections (all drilled with seawater 
and viscous sweeps only) plus cement discharged while cementing the 30- 
and 20-in. (76- and 51-cm) casing strings will be discharged on the 
surface of the seafloor under provisions of an approved National 
Pollutant Discharge Elimination System (NPDES) General Permit (GP) 
administered by the U.S. Environmental Protection Agency (EPA). The 
most recent NPDES GP expired on June 26, 2011. The EPA is currently 
processing two separate requests for NPDES exploration GPs in the 
Beaufort and Chukchi seas.
    The NPDES GP establishes discharge limits for drilling fluids (at 
the end of a discharge pipe) to a minimum 96-hr LC50 of 
30,000 parts per million. Both modeling and field studies have shown 
that discharged drilling fluids are diluted rapidly in receiving waters 
(Ayers et al., 1980a,b; Brandsma et al., 1980; NRC, 1983; O'Reilly et 
al., 1989; Nedwed et al., 2004; Smith et al., 2004; Neff, 2005). The 
dilution rate is strongly affected by the discharge rate; the NPDES GP 
limits the discharge of cuttings and fluids to 750 bbl/hr. For example, 
the EPA modeled hypothetical 750 bbl/hr discharges of drilling fluids 
in water depths of 66 ft (20 m) in the Beaufort and Chukchi Seas and 
predicted a minimum dilution of 1,326:1 at 330 ft (100 m).
    Modeling of similar discharges offshore of Sakhalin Island 
predicted a 1,000-fold dilution within 10 minutes and 330 ft (100 m) of 
the discharge. In a field study (O'Reilly et al., 1989) of a drilling 
waste discharge offshore of California, a 270 bbl discharge of drilling 
fluids was found to be diluted 183-fold at 33 ft (10 m) and 1,049-fold 
at 330 ft (100 m). Neff (2005) concluded that concentrations of 
discharged drilling fluids drop to levels that would have no effect 
within about two minutes of discharge and within 16 ft (5 m) of the 
discharge location.
    Based on the fact that Shell plans to store the drilling muds and 
other liquid waste streams and transport them to a site onshore, no 
impacts to marine mammal habitat or marine mammal prey species are 
anticipated from such an activity.

Potential Impacts From Drillship Presence

    The Kulluk is 266 ft (81 m) in diameter, and the Discoverer is 514 
ft (156.7 m) long. If an animal's swim path is directly perpendicular 
to the drillship, the animal will need to swim around the ship in order 
to pass through the area. The diameter of the Kulluk or the length of 
the Discoverer (approximately one and a half football fields) is not 
significant enough to cause a large-scale diversion from the animals' 
normal swim and migratory paths. Additionally, the eastward spring 
bowhead whale migration will not be affected by the proposed 
exploratory drilling program because the migration will occur prior to 
Shell's arrival in the Beaufort Sea. The westward fall bowhead whale 
migration begins in late August/early September and lasts through 
October. As discussed throughout this document, Shell plans to suspend 
all operations on August 25, move the drillship and all support vessels 
out of the area to a location north and west of the well sites, and 
will not resume drilling activities until the close of the Kaktovik and 
Nuiqsut (Cross Island) bowhead subsistence hunts. This will reduce the 
amount of time that the Kulluk or Discoverer may impede the bowheads' 
normal swim and migratory paths as they move through Camden Bay. 
Moreover, any deflection of bowhead whales or other marine mammal 
species due to the physical presence of the drillship or its support 
vessels would be very minor. The drillship's physical footprint is 
small relative to the size of the geographic region it will occupy and 
will likely not cause marine mammals to deflect

[[Page 69001]]

greatly from their typical migratory route. Also, even if animals may 
deflect because of the presence of the drillship, the Beaufort Sea's 
migratory corridor is much larger in size than the length of the 
drillship (many dozens of miles vs. less than two football fields), and 
animals would have other means of passage around the drillship. While 
there are other vessels that will be on location to support the 
drillship, most of those vessels will remain within a few kilometers of 
the drillship (with the exception of the ice management vessels which 
will remain approximately 25 mi [40 km] upwind of the drillship when 
not in use). In sum, the physical presence of the drillship is not 
likely to cause a significant deflection to migrating marine mammals.

Potential Impacts From an Oil Spill

    Arctic cod and other fishes are a principal food item for beluga 
whales and seals in the Beaufort Sea. Anadromous fish are more 
sensitive to oil when in the marine environment than when in the fresh 
water environment (Moles et al., 1979). Generally, arctic fish are more 
sensitive to oil than are temperate species (Rice et al., 1983). 
However, fish in the open sea are unlikely to be affected by an oil 
spill. Fish in shallow nearshore waters could sustain heavy mortality 
if an oil slick were to remain in the area for several days or longer. 
Fish concentrations in shallow nearshore areas that are used as feeding 
habitat for seals and whales could be unavailable as prey. Because the 
animals are mobile, effects would be minor during the ice-free period 
when whales and seals could go to unaffected areas to feed.
    Effects of oil on zooplankton as food for bowhead whales were 
discussed by Richardson ([ed.] 1987). Zooplankton populations in the 
open sea are unlikely to be depleted by the effects of an oil spill. 
Oil concentrations in water under a slick are low and unlikely to have 
anything but very minor effects on zooplankton. Zooplankton populations 
in near surface waters could be depleted; however, concentrations of 
zooplankton in near-surface waters generally are low compared to those 
in deeper water (Bradstreet et al., 1987; Griffiths et al., 2002).
    Some bowheads feed in shallow nearshore waters (Bradstreet et al., 
1987; Richardson and Thomson [eds.], 2002). Wave action in nearshore 
waters could cause high concentrations of oil to be found throughout 
the water column. Oil slicks in nearshore feeding areas could 
contaminate food and render the site unusable as a feeding area. 
Additionally, gray whales do not commonly feed in the Beaufort Sea and 
are rarely seen near the proposed drill sites in Camden Bay.
    Effects of oil spills on zooplankton as food for seals would be 
similar to those described above for bowhead whales. During the ice-
free period, effects on seal feeding would be minor.
    Bearded seals consume benthic animals. Wave action in nearshore 
waters could cause oil to reach the bottom through adherence to 
suspended sediments (Sanders et al., 1990). There could be mortality of 
benthic animals and elimination of some benthic feeding habitat. During 
the ice-free period, effects on seal feeding would be minor. During the 
ice-free period, seals and whales could find alternate feeding 
habitats.
    Depending on the timing of a spill, planktonic larval forms of 
organisms in arctic kelp communities such as annelids, mollusks, and 
crustaceans may be affected by floating oil. The contact may occur 
anywhere near the surface of the water column (MMS, 1996). Due to their 
wide distribution, large numbers, and rapid rate of regeneration, the 
recovery of marine invertebrate populations is expected to occur soon 
after the surface oil passes. Spill response activities are not likely 
to disturb the prey items of whales or seals sufficiently to cause more 
than minor effects. Spill response activities could cause marine 
mammals to avoid the disturbed habitat that is being cleaned. However, 
by causing avoidance, animals would avoid impacts from the oil itself. 
Additionally, the likelihood of an oil spill is expected to be very 
low, as discussed earlier in this document.

Potential Impacts From Ice Management/Icebreaking Activities

    Ice management activities include the physical pushing or moving of 
ice to create more open-water in the proposed drilling area and to 
prevent ice floes from striking the drillship. Icebreaking activities 
include the physical breaking of ice. Shell does not intend to conduct 
icebreaking activities. However, should there be a need for 
icebreaking, it would only be performed in order to safely move the 
drillship and other vessels off location and to end operations for the 
season. Ringed, bearded, spotted, and ribbon seals (along with the 
walrus) are dependent on sea ice for at least part of their life 
history. Sea ice is important for life functions such as resting, 
breeding, and molting. These species are dependent on two different 
types of ice: pack ice and landfast ice. Should ice management/
icebreaking activities be necessary during the proposed drilling 
program, Shell would only manage pack ice in either early to mid-July 
or mid- to late October. Landfast ice would not be present during 
Shell's proposed operations.
    The ringed seal is the most common pinniped species in the proposed 
project area. While ringed seals use ice year-round, they do not 
construct lairs for pupping until late winter/early spring on the 
landfast ice. Therefore, since Shell plans to conclude drilling on 
October 31, Shell's activities would not impact ringed seal lairs or 
habitat needed for breeding and pupping in the Camden Bay area. Ringed 
seals can be found on the pack ice surface in the late spring and early 
summer in the Beaufort Sea, the latter part of which may overlap with 
the start of Shell's proposed drilling activities. If an ice floe is 
pushed into one that contains hauled out seals, the animals may become 
startled and enter the water when the two ice floes collide. Bearded 
seals breed in the Bering and Chukchi Seas, as the Beaufort Sea 
provides less suitable habitat for the species. Spotted seals are even 
less common in the Camden Bay area. This species does not breed in the 
Beaufort Sea. Additionally, ribbon seals are not known to breed in the 
Beaufort Sea. Therefore, ice used by bearded, spotted, and ribbon seals 
needed for life functions such as breeding and molting would not be 
impacted as a result of Shell's drilling program since these life 
functions do not occur in the proposed project area. For ringed seals, 
ice management/icebreaking would occur during a time when life 
functions such as breeding, pupping, and molting do not occur in the 
proposed activity area. Additionally, these life functions normally 
occur on landfast ice, which will not be impacted by Shell's activity.

Proposed 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). Later in 
this document in the ``Proposed Incidental Harassment Authorization'' 
section, NMFS lays out the proposed conditions

[[Page 69002]]

for review, as they would appear in the final IHA (if issued).

Mitigation Measures Proposed by Shell

    Shell submitted a 4MP as part of its application (Attachment C; see 
ADDRESSES). Shell's 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 fall bowhead whale hunts from 
Kaktovik, Nuiqsut (Cross Island), and Barrow;
     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 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 and shutting down 
activities for a portion of the open-water season.
    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 [mu]Pa (rms) for cetaceans and 
greater than or equal to 190 dB re 1 [mu]Pa (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 could occur (see Southall et al., 2007). With 
respect to Level B harassment, NMFS' practice has been to apply the 120 
dB re 1 [mu]Pa (rms) received level threshold for underwater continuous 
sound levels and the 160 dB re 1 [mu]Pa (rms) received level threshold 
for underwater impulsive sound levels.
    Shell proposes to monitor the various radii in order to implement 
any mitigation measures that may be necessary. Initial radii for the 
sound levels produced by the Kulluk and Discoverer, the icebreaker, and 
the airguns have been modeled. Measurements taken by Greene (1987a) 
indicated a broadband source level of 185.5 dB re 1 [mu]Pa rms for the 
Kulluk. Measurements taken by Austin and Warner (2010) indicated 
broadband source levels between 177 and 185 dB re 1 [mu]Pa 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 [mu]Pa 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 [mu]Pa rms. Once on location in Camden Bay, Shell will 
conduct sound source verification (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 earlier in this document and in Shell's 4MP for the 
drillships 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 Protected Species Observers 
(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 should in-field measurements of the operations indicate that 
such measures are necessary. Additional details on the PSO program are 
described in the ``Proposed Monitoring and Reporting'' section found 
later in this document. Also, for the ZVSP activities, Shell proposes 
to 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 proposed 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-minutes 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-
minutes 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

[[Page 69003]]

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 proposed by Shell include: (1) 
Reducing speed and/or changing course if a marine mammal is sighted 
from a vessel in transit (NMFS has proposed a specific distance in the 
next subsection); (2) resuming full activity (e.g., full support vessel 
speed) only after marine mammals are confirmed to be outside the safety 
zone; (3) implementing flight restrictions prohibiting aircraft from 
flying below 1,500 ft (457 m) altitude (except during takeoffs and 
landings or in emergency situations); and (4) keeping vessels anchored 
when approached by marine mammals to avoid the potential for avoidance 
reactions by such animals.
    Shell has also proposed 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.

Additional Mitigation Measures Proposed by NMFS

    In addition to the mitigation measures proposed in Shell's IHA 
application, NMFS proposes the following measures (which apply to 
vessel operations) be included in the IHA, if issued, in order to 
ensure the least practicable impact on the affected species or stocks. 
NMFS proposes to require Shell to avoid multiple changes in direction 
or speed when within 300 yards (274 m) of whales. Additionally, NMFS 
proposes to require Shell to reduce speed in inclement weather.

Oil Spill Contingency Plan

    In accordance with BOEM regulations, Shell has developed an Oil 
Discharge Prevention and Contingency Plan (ODPCP) for its Camden Bay 
exploration drilling program. A copy of this document can be found on 
the Internet at: http://www.alaska.boemre.gov/fo/ODPCPs/2010_BF_rev1.pdf. Additionally, in its Plan of Cooperation (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. The ODPCP is currently under review by 
the Department of the Interior and other agencies. A final decision on 
the adequacy of the ODPCP is expected prior to the start of Shell's 
2012 Beaufort Sea drilling program.
    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.
    Proposed measures to ensure availability of such species or stock 
for taking for certain subsistence uses is discussed later in this 
document (see ``Impact on Availability of Affected Species or Stock for 
Taking for Subsistence Uses'' section).

Proposed Monitoring and Reporting

    In order to issue an ITA for an activity, Section 101(a)(5)(D) of 
the MMPA states that NMFS must, 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 proposed action area.

Monitoring Measures Proposed by Shell

    The monitoring plan proposed by Shell can be found in the 4MP 
(Attachment C of Shell's application; see ADDRESSES). The plan may be 
modified or supplemented based on comments or new information received 
from the public during the public comment period or from the peer 
review panel (see the ``Monitoring Plan Peer Review'' section later in 
this document). A summary of the primary components of the plan 
follows. Later in this document in the ``Proposed Incidental Harassment 
Authorization'' section, NMFS lays out the proposed monitoring and 
reporting conditions, as well as the mitigation conditions, for review, 
as they would appear in the final IHA (if issued).
(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 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.
    Biologist-observers will have previous marine mammal observation 
experience, and field crew leaders will be highly experienced with 
previous vessel-based marine mammal monitoring projects. Resumes for 
those individuals will be provided to NMFS so that NMFS can review and 
accept their qualifications. Inupiat observers will be experienced in 
the region, familiar with the marine mammals of the area, and complete 
a NMFS approved observer training course designed to familiarize 
individuals with monitoring and data collection procedures. A handbook, 
adapted for the specifics of the planned Shell drilling program, will 
be prepared and distributed beforehand to all PSOs.
    PSOs will watch for marine mammals from the best available vantage 
point on the drillship and support vessels. PSOs will scan 
systematically with the unaided eye and 7 x 50 reticle binoculars, 
supplemented with 20 x 60 image-stabilized Zeiss Binoculars or Fujinon 
25 x 150 ``Big-eye'' binoculars and night-vision equipment when needed. 
Personnel on the bridge will assist the PSOs in watching for marine 
mammals. New or inexperienced PSOs will be paired with an experienced 
PSO or experienced field biologist so that the

[[Page 69004]]

quality of marine mammal observations and data recording is kept 
consistent.
    Information to be recorded by PSOs will include the same types of 
information that were recorded during recent monitoring programs 
associated with industry activity in the Arctic (e.g., Ireland et al., 
2009). The recording will include information about the animal sighted, 
environmental and operational information, and the position of other 
vessels in the vicinity of the sighting. The ship's position, speed of 
support vessels, and water temperature, water depth, sea state, ice 
cover, visibility, and sun glare will also be recorded at the start and 
end of each observation watch, every 30 minutes during a watch, and 
whenever there is a change in any of those variables.
    Distances to nearby marine mammals will be estimated with 
binoculars (Fujinon 7 x 50 binoculars) containing a reticle to measure 
the vertical angle of the line of sight to the animal relative to the 
horizon. PSOs may use a laser rangefinder to test and improve their 
abilities for visually estimating distances to objects in the water. 
However, previous experience showed that a Class 1 eye-safe device was 
not able to measure distances to seals more than about 230 ft (70 m) 
away. The device was very useful in improving the distance estimation 
abilities of the observers at distances up to about 1968 ft (600 m)--
the maximum range at which the device could measure distances to highly 
reflective objects such as other vessels. Humans observing objects of 
more-or-less known size via a standard observation protocol, in this 
case from a standard height above water, quickly become able to 
estimate distances within about 20% when given immediate 
feedback about actual distances during training.
(2) Aerial Survey Program
    Shell proposes to conduct an aerial survey program in support of 
the drilling program in the Beaufort Sea during the summer and fall of 
2012. Shell's objectives for this program include:
    (A) To advise operating vessels as to the presence of marine 
mammals (primarily cetaceans) in the general area of operation;
    (B) To collect and report data on the distribution, numbers, 
movement and behavior of marine mammals near the drilling operations 
with special emphasis on migrating bowhead whales;
    (C) To support regulatory reporting related to the estimation of 
impacts of drilling operations on marine mammals;
    (D) To investigate potential deflection of bowhead whales during 
migration by documenting how far east of drilling operations a 
deflection may occur and where whales return to normal migration 
patterns west of the operations; and
    (E) To monitor the accessibility of bowhead whales to Inupiat 
hunters.
    Aerial survey flights will begin 5 to 7 days before operations at 
the exploration well sites get underway. Surveys will be flown daily 
throughout drilling operations, weather and flight conditions 
permitting, and continue for 5 to 7 days after all activities at the 
site have ended.
    The aerial survey procedures will be generally consistent with 
those used during earlier industry studies (Davis et al., 1985; Johnson 
et al., 1986; Evans et al., 1987; Miller et al., 1997, 1998, 1999, 
2002; Patterson, 2007). This will facilitate comparison and pooling of 
data where appropriate. However, the specific survey grids will be 
tailored to Shell's operations. During the 2012 drilling season, Shell 
will coordinate and cooperate with the aerial surveys conducted by 
BOEMRE/NMFS and any other groups conducting surveys in the same region.
    For marine mammal monitoring flights, aircraft will be flown at 
approximately 120 knots (138 mph) ground speed and usually at an 
altitude of 1,000 ft (305 m). Surveys in the Beaufort Sea are directed 
at bowhead whales, and an altitude of 900-1,000 ft (274-305 m) is the 
lowest survey altitude that can normally be flown without concern about 
potential aircraft disturbance. Aerial surveys at an altitude of 1,000 
ft (305 m) do not provide much information about seals but are suitable 
for both bowhead and beluga whales. The need for a 900-1000+ (374-305 
m) ft cloud ceiling will limit the dates and times when surveys can be 
flown.
    Two primary observers will be seated at bubble windows on either 
side of the aircraft, and a third observer will observe part time and 
record data the rest of the time. All observers need bubble windows to 
facilitate downward viewing. For each marine mammal sighting, the 
observer will dictate the species, number, size/age/sex class when 
determinable, activity, heading, swimming speed category (if 
traveling), sighting cue, ice conditions (type and percentage), and 
inclinometer reading to the marine mammal into a digital recorder. The 
inclinometer reading will be taken when the animal's location is 
90[deg] to the side of the aircraft track, allowing calculation of 
lateral distance from the aircraft trackline.
    Transect information, sighting data and environmental data will be 
entered into a GPS-linked computer by the third observer and 
simultaneously recorded on digital voice recorders for backup and 
validation. At the start of each transect, the observer recording data 
will record the transect start time and position, ceiling height (ft), 
cloud cover (in 10ths), wind speed (knots), wind direction ([deg]T) and 
outside air temperature ([deg]C). In addition, each observer will 
record the time, visibility (subjectively classified as excellent, 
good, moderately impaired, seriously impaired or impossible), sea state 
(Beaufort wind force), ice cover (in 10ths) and sun glare (none, 
moderate, severe) at the start and end of each transect, and at 2 min 
intervals along the transect. The data logger will automatically record 
time and aircraft position (latitude and longitude) for sightings and 
transect waypoints, and at pre-selected intervals along the transects. 
Ice observations during aerial surveys will be recorded and satellite 
imagery may be used, where available, during post-season analysis to 
determine ice conditions adjacent to the survey area. These are 
standard practices for surveys of this type and are necessary in order 
to interpret factors responsible for variations in sighting rates.
    During the late summer and fall, the bowhead whale is the primary 
species of concern, but belugas and gray whales are also present. To 
address concerns regarding deflection of bowheads at greater distances, 
the survey pattern around drilling operations has been designed to 
document whale distribution from about 25 mi (40 km) east of the 
drilling operations to about 37 mi (60 km) west of operations (see 
Figure 1 of Shell's 4MP).
    Bowhead whale movements during the late summer/autumn are generally 
from east to west, and transects should be designed to intercept rather 
than parallel whale movements. The transect lines in the grid will be 
oriented north-south, equally spaced at 5 mi (8 km) and randomly 
shifted in the east-west direction for each survey by no more than the 
transect spacing. The survey grid will total about 808 mi (1,300 km) in 
length, requiring approximately 6 hours to survey at a speed of 120 
knots (138 mph), plus ferry time. Exact lengths and durations will vary 
somewhat depending on the position of the drilling operation and thus 
of the grid, the sequence in which lines are flown (often affected by 
weather), and the number of refueling/rest stops.
    Weather permitting, transects making up the grid in the Beaufort 
Sea will be flown in sequence from west to east. This decreases 
difficulties associated

[[Page 69005]]

with double counting of whales that are (predominantly) migrating 
westward. The survey sequence around the drilling operation is designed 
to monitor the distribution of whales around the drilling operation.
    Shell's 4MP provides an explanation about the importance of 
statistical power in the sampling design and how the aerial survey data 
will be analyzed. Please refer to the 4MP for that information (see 
ADDRESSES).
(3) Acoustic Monitoring
    Shell will conduct SSV tests to establish the isopleths for the 
applicable exclusion radii, mostly to be employed during the ZVSP 
surveys. In addition, Shell proposes to use acoustic recorders to study 
bowhead deflections.
    Drilling Sound Measurements--Drilling sounds are expected to vary 
significantly with time due to variations in the level of operations 
and the different types of equipment used at different times onboard 
the Kulluk or Discoverer. The objectives of these measurements are:
    (1) To quantify the absolute sound levels produced by drilling and 
to monitor their variations with time, distance, and direction from the 
drilling vessel;
    (2) to measure the sound levels produced by vessels operating in 
support of exploration drilling operations. These vessels will include 
crew change vessels, tugs, icebreakers, and OSRVs; and
    (3) to measure the sound levels produced by an end-of-hole ZVSP 
survey, using a stationary sound source.
    The Kulluk or Discoverer, support vessels, and ZVSP sound 
measurements will be performed using one of two methods, both of which 
involve real-time monitoring. The first method would involve use of 
bottom-founded hydrophones cabled back to the Kulluk or Discoverer (see 
Figure 2 in Shell's 4MP). These hydrophones would be positioned between 
1,640 ft (500 m) and 3,281 ft (1,000 m) from the Kulluk or Discoverer, 
depending on the final positions of the anchors used to hold the Kulluk 
or Discoverer in place. Hydrophone cables would be fed to real-time 
digitization systems onboard. In addition to the cabled system, a 
separate set of bottom-founded hydrophones (see Figure 3 in Shell's 
4MP) may be deployed at various distances from the exploration drilling 
operation for storage of acoustic data to be retrieved and processed at 
a later date.
    As an alternative to the cabled hydrophone system (and possible 
inclusion of separate bottom-founded hydrophones), the second (or 
alternative) monitoring method would involve a radio buoy approach 
deploying four sparbuoys 4-5 mi (6-8 km) from the Kulluk or Discoverer. 
Additional hydrophones may be deployed closer to the Kulluk or 
Discoverer, if necessary, to better determine sound source levels. 
Monitoring personnel and recording/receiving equipment would be onboard 
one of the support vessels with 24-hr monitoring capacity. The system 
would allow for collection and processing of real-time data similar to 
that provided by the cabled system but from a wider range of locations.
    Sound level monitoring with either method will occur on a 
continuous basis throughout all exploration drilling activities. Both 
types of systems will be set to record digital acoustic data at a 
sample rate of 32 kHz, providing useful acoustic bandwidth to at least 
15 kHz. These systems are capable of measuring absolute broadband sound 
levels between 90 and 180 dB re 1 [micro]Pa. The long duration 
recordings will capture many different operations performed from the 
drillship. Retrieval of these systems will occur following completion 
of the exploration drilling activities.
    These recorders will provide a capability to examine sound levels 
produced by different drilling activities and practices. This system 
will not have the capability to locate calling marine mammals and will 
indicate only relative proximity. The system will be evaluated during 
operations for its potential to improve PSO observations through 
notification of PSOs on vessel and aircraft of high levels of call 
detections and their general locations.
    The deployment of drilling sound monitoring equipment will occur as 
soon as possible once the drillship is on site. Activity logs of 
exploration drilling operations and nearby vessel activities will be 
maintained to correlate with these acoustic measurements. This 
equipment will also be used to take measurements of the support vessels 
and airguns. Additional details can be found in Shell's 4MP.
    Shell plans to deploy arrays of acoustic recorders in the Beaufort 
Sea in 2012, similar to that which was done in 2007 through 2010 using 
Directional Autonomous Seafloor Acoustic Recorders (DASARs). These 
directional acoustic systems permit localization of bowhead whale and 
other marine mammal vocalizations. The purpose of the array will be to 
further understand, define, and document sound characteristics and 
propagation resulting from vessel-based drilling operations that may 
have the potential to cause deflections of bowhead whales from their 
migratory pathway. Of particular interest will be the east-west extent 
of deflection, if any (i.e., how far east of a sound source do bowheads 
begin to deflect and how far to the west beyond the sound source does 
deflection persist). Of additional interest will be the extent of 
offshore (or towards shore) deflection that might occur.
    In previous work around seismic and drillship operations in the 
Alaskan Beaufort Sea, the primary method for studying this question has 
been aerial surveys. Acoustic localization methods will provide 
supplementary information for addressing the whale deflection question. 
Compared to aerial surveys, acoustic methods have the advantage of 
providing a vastly larger number of whale detections, and can operate 
day or night, independent of visibility, and to some degree independent 
of ice conditions and sea state--all of which prevent or impair aerial 
surveys. However, acoustic methods depend on the animals to call, and 
to some extent, assume that calling rate is unaffected by exposure to 
industrial noise. Bowheads call frequently in fall, but there is some 
evidence that their calling rate may be reduced upon exposure to 
industrial sounds, complicating interpretation. The combined use of 
acoustic and aerial survey methods will provide a suite of information 
that should be useful in assessing the potential effects of drilling 
operations on migrating bowhead whales.
    Using passive acoustics with directional autonomous recorders, the 
locations of calling whales will be observed for a 6- to 10-week 
continuous monitoring period at five coastal sites (subject to 
favorable ice and weather conditions). Essential to achieving this 
objective is the continuous measurement of sound levels near the 
drillship.
    Shell plans to conduct the whale migration monitoring using the 
passive acoustics techniques developed and used successfully since 2001 
for monitoring the migration past Northstar production island northwest 
of Prudhoe Bay and from Kaktovik to Harrison Bay during the 2007 
through 2011 migrations. Those techniques involve using DASARs to 
measure the arrival angles of bowhead calls at known locations, then 
triangulating to locate the calling whale.
    In attempting to assess the responses of bowhead whales to the 
planned industrial operations, it will be essential to monitor whale 
locations at sites both near and far from industry activities. Shell 
plans to monitor at five sites along the Alaskan Beaufort coast as 
shown in

[[Page 69006]]

Figure 9 of Shell's 4MP. The eastern-most site (5 in Figure 9 
of the 4MP) will be just east of Kaktovik (approximately 62 mi [100 km] 
west of the Sivulliq drilling area) and the western-most site 
(1 in Figure 10 of the 4MP) will be in the vicinity of 
Harrison Bay (approximately 109 mi [175 km] west of Sivulliq) . Site 2 
will be located west of Prudhoe Bay (approximately 68 mi [110 km] west 
of Sivulliq). Site 4 will be approximately 6.2 mi (10 km) east of the 
Sivulliq drilling area, and site 3 will be approximately 15.5 mi (25 
km) west of Sivulliq. These five sites will provide information on 
possible migration deflection well in advance of whales encountering an 
industry operation and on ``recovery'' after passing such operations 
should a deflection occur.
    The proposed geometry of DASARs at each site is comprised of seven 
DASARs oriented in a north-south pattern so that five equilateral 
triangles with 4.3-mi (7-km) element spacing is achieved. DASARs will 
be installed at planned locations using a GPS. However, each DASAR's 
orientation once it settles on the bottom is unknown and must be 
determined to know how to reference the call angles measured to the 
whales. Also, the internal clocks used to sample the acoustic data 
typically drift slightly, but linearly, by an amount up to a few 
seconds after 6 weeks of autonomous operation. Knowing the time 
differences within a second or two between DASARs is essential for 
identifying identical whale calls received on two or more DASARs. 
Bowhead migration begins in late August with the whales moving westward 
from their feeding sites in the Canadian Beaufort Sea. It continues 
through September and well into October. However, because of the 
drilling schedule, Shell will attempt to install the 21 DASARs at three 
sites (3, 4 and 5) in early August. The remaining 14 DASARs will be 
installed at sites 1 and 2 in late August. Thus, Shell proposes to be 
monitoring for whale calls from before August 15 until sometime before 
October 15.
    At the end of the season, the fourth DASAR in each array will be 
refurbished, recalibrated, and redeployed to collect data through the 
winter. The other DASARs in the arrays will be recovered. The 
redeployed DASARs will be programmed to record 35 min every 3 hours 
with a disk capacity of 10 months at that recording rate. This should 
be ample space to allow over-wintering from approximately mid-October 
2012, through mid-July 2013.
    Additional details on methodology and data analysis for the three 
types of monitoring described here (i.e., vessel-based, aerial, and 
acoustic) can be found in the 4MP in Shell's application (see 
ADDRESSES).

Monitoring Plan Peer Review

    The MMPA requires that monitoring plans be independently peer 
reviewed ``where the proposed activity may affect the availability of a 
species or stock for taking for subsistence uses'' (16 U.S.C. 
1371(a)(5)(D)(ii)(III)). Regarding this requirement, NMFS' implementing 
regulations state, ``Upon receipt of a complete monitoring plan, and at 
its discretion, [NMFS] will either submit the plan to members of a peer 
review panel for review or within 60 days of receipt of the proposed 
monitoring plan, schedule a workshop to review the plan'' (50 CFR 
216.108(d)).
    NMFS has established an independent peer review panel to review 
Shell's 4MP for Exploration Drilling of Selected Lease Areas in the 
Alaskan Beaufort Sea in 2012. The panel is scheduled to meet in early 
January 2012, and will provide comments to NMFS shortly after they 
meet. After completion of the peer review, NMFS will consider all 
recommendations made by the panel, incorporate appropriate changes into 
the monitoring requirements of the IHA (if issued), and publish the 
panel's findings and recommendations in the final IHA notice of 
issuance or denial document.

Reporting Measures

(1) SSV Report
    A report on the preliminary results of the acoustic verification 
measurements, including as a minimum the measured 190-, 180-, 160-, and 
120-dB (rms) radii of the drillship, support vessels, and airgun array 
will be submitted within 120 hr after collection and analysis of those 
measurements at the start of the field season or in the case of the 
airgun once that part of the program is implemented. This report will 
specify the distances of the exclusion zones that were adopted for the 
exploratory drilling program. Prior to completion of these 
measurements, Shell will use the radii outlined in their application 
and elsewhere in this document.
(2) Technical Reports
    The results of Shell's 2012 Camden Bay exploratory drilling 
monitoring program (i.e., vessel-based, aerial, and acoustic) will be 
presented in the ``90-day'' and Final Technical reports, as required by 
NMFS under the proposed IHA. Shell proposes that the Technical Reports 
will include: (1) Summaries of monitoring effort (e.g., total hours, 
total distances, and marine mammal distribution through study period, 
accounting for sea state and other factors affecting visibility and 
detectability of marine mammals); (2) analyses of the effects of 
various factors influencing detectability of marine mammals (e.g., sea 
state, number of observers, and fog/glare); (3) species composition, 
occurrence, and distribution of marine mammal sightings, including 
date, water depth, numbers, age/size/gender categories (if 
determinable), group sizes, and ice cover; (4) sighting rates of marine 
mammals during periods with and without drilling activities (and other 
variables that could affect detectability); (5) initial sighting 
distances versus drilling state; (6) closest point of approach versus 
drilling state; (7) observed behaviors and types of movements versus 
drilling state; (8) numbers of sightings/individuals seen versus 
drilling state; (9) distribution around the drillship and support 
vessels versus drilling state; and (10) estimates of take by 
harassment. This information will be reported for both the vessel-based 
and aerial monitoring.
    Analysis of all acoustic data will be prioritized to address the 
primary questions, which are to: (a) Determine when, where, and what 
species of animals are acoustically detected on each DASAR; (b) analyze 
data as a whole to determine offshore bowhead distributions as a 
function of time; (c) quantify spatial and temporal variability in the 
ambient noise; and (d) measure received levels of drillship activities. 
The bowhead detection data will be used to develop spatial and temporal 
animal distributions. Statistical analyses will be used to test for 
changes in animal detections and distributions as a function of 
different variables (e.g., time of day, time of season, environmental 
conditions, ambient noise, vessel type, operation conditions).
    The initial technical report is due to NMFS within 90 days of the 
completion of Shell's Beaufort Sea exploratory drilling program. The 
``90-day'' report will be subject to review and comment by NMFS. Any 
recommendations made by NMFS must be addressed in the final report 
prior to acceptance by NMFS.
(3) Comprehensive Report
    Following the 2012 drilling season, a comprehensive report 
describing the vessel-based, aerial, and acoustic monitoring programs 
will be prepared. The comprehensive report will describe the methods, 
results, conclusions and limitations of each of the individual data 
sets in detail. The report will also integrate (to the extent possible) 
the studies into a broad based assessment of

[[Page 69007]]

industry activities, and other activities that occur in the Beaufort 
and/or Chukchi seas, and their impacts on marine mammals during 2012. 
The report will help to establish long-term data sets that can assist 
with the evaluation of changes in the Chukchi and Beaufort Sea 
ecosystems. The report will attempt to provide a regional synthesis of 
available data on industry activity in offshore areas of northern 
Alaska that may influence marine mammal density, distribution and 
behavior.
(4) Notification of Injured or Dead Marine Mammals
    Shell will be required to notify NMFS' Office of Protected 
Resources and NMFS' Stranding Network of any sighting of an injured or 
dead marine mammal. Based on different circumstances, Shell may or may 
not be required to stop operations upon such a sighting. Shell will 
provide NMFS with the species or description of the animal(s), the 
condition of the animal(s) (including carcass condition if the animal 
is dead), location, time of first discovery, observed behaviors (if 
alive), and photo or video (if available). The specific language for 
what Shell must do upon sighting a dead or injured marine mammal can be 
found in the ``Proposed Incidental Harassment Authorization'' section 
of this document.

Estimated Take by Incidental Harassment

    Except with respect to certain activities not pertinent here, the 
MMPA defines ``harassment'' as: any act of pursuit, torment, or 
annoyance which (i) Has the potential to injure a marine mammal or 
marine mammal stock in the wild [Level A harassment]; or (ii) has the 
potential to disturb a marine mammal or marine mammal stock in the wild 
by causing disruption of behavioral patterns, including, but not 
limited to, migration, breathing, nursing, breeding, feeding, or 
sheltering [Level B harassment]. Only take by Level B behavioral 
harassment is anticipated as a result of the proposed drilling program. 
Noise propagation from the drillship, associated support vessels 
(including during icebreaking if needed), and the airgun array are 
expected to harass, through behavioral disturbance, affected marine 
mammals species or stocks. Additional disturbance to marine mammals may 
result from aircraft overflights and visual disturbance of the 
drillship or support vessels. However, based on the flight paths and 
altitude, impacts from aircraft operations are anticipated to be 
localized and minimal in nature.
    The full suite of potential impacts to marine mammals from various 
industrial activities was described in detail in the ``Potential 
Effects of the Specified Activity on Marine Mammals'' section found 
earlier in this document. The potential effects of sound from the 
proposed 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). 
As discussed earlier in this document, NMFS estimates that Shell's 
activities will most likely result in behavioral disturbance, including 
avoidance of the ensonified area or changes in speed, direction, and/or 
diving profile of one or more marine mammals. For reasons discussed 
previously in this document, hearing impairment (TTS and PTS) is highly 
unlikely to occur based on the fact that most of the equipment to be 
used during Shell's proposed drilling program does not have source 
levels high enough to elicit even mild TTS and/or the fact that certain 
species are expected to avoid the ensonified areas close to the 
operations. Additionally, non-auditory physiological effects are 
anticipated to be minor, if any would occur at all. Finally, based on 
the proposed mitigation and monitoring measures described earlier in 
this document and the fact that the back-propagated source levels for 
the drillships proposed to be used are estimated to be between 177 and 
185 dB re 1 [mu]Pa (rms), no injury or mortality of marine mammals is 
anticipated as a result of Shell's proposed exploratory drilling 
program.
    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. Shell provided calculations for the 
120-dB isopleths produced by both the Kulluk and the Discoverer and by 
the icebreaker during icebreaking activities and then used those 
isopleths to estimate takes by harassment. Additionally, Shell provided 
calculations for the 160-dB isopleth produced by the airgun array and 
then used that isopleth to estimate takes by harassment. Shell provides 
a full description of the methodology used to estimate takes by 
harassment in its IHA application (see ADDRESSES), which is also 
provided in the following sections.
    Shell has requested authorization to take bowhead, gray, and beluga 
whales, harbor porpoise, and ringed, spotted, bearded, and ribbon seals 
incidental to exploration drilling, ice management/icebreaking, and 
ZVSP activities. Additionally, Shell provided exposure estimates and 
requested takes of narwhal. However, as stated previously in this 
document, sightings of this species are rare, and the likelihood of 
occurrence of narwhals in the proposed drilling area is minimal. 
Therefore, NMFS has not proposed to authorize take for narwhals.

Basis for Estimating ``Take by Harassment''

    ``Take by Harassment'' is described in this section and was 
calculated in Shell's application by multiplying the expected densities 
of marine mammals that may occur near the exploratory drilling 
operations by the area of water likely to be exposed to continuous, 
non-pulse sounds >=120 dB re 1 [mu]Pa (rms) during drillship operations 
or icebreaking activities and impulse sounds >=160 dB re 1 [mu]Pa (rms) 
created by seismic airguns during ZVSP activities. The single exception 
to this method is for the estimation of exposures of bowhead whales 
during the fall migration where more detailed data were available, 
allowing an alternate approach, described below, to be used. NMFS 
evaluated and critiqued the methods provided in Shell's application and 
determined that they were appropriate. This section describes the 
estimated densities of marine mammals that may occur in the project 
area. The area of water that may be ensonified to the above sound 
levels is described further in the ``Estimated Area Exposed to Sounds 
120 dB or 160 dB re 1 [mu]Pa rms'' subsection.
    Marine mammal densities near the operation are likely to vary by 
season and habitat. However, sufficient published data allowing the 
estimation of separate densities during summer (July and August) and 
fall (September and October) are only available for beluga and bowhead 
whales. As noted above, exposures of bowhead whales during the fall are 
not calculated using densities (see below). Therefore, summer and fall 
densities have been estimated for beluga whales, and a summer density 
has been estimated for bowhead whales. Densities of all other species 
have been estimated to represent the duration of both seasons.
    Marine mammal densities are also likely to vary by habitat type. In 
the Alaskan Beaufort Sea, where the

[[Page 69008]]

continental shelf break is relatively close to shore, marine mammal 
habitat is often defined by water depth. Bowhead and beluga occurrence 
within nearshore (0-131 ft, 0-40 m), outer continental shelf (131-656 
ft, 40-200 m), slope (656-6,562 ft, 200-2000 m), basin (>6,562 ft, 2000 
m), or similarly defined habitats have been described previously (Moore 
et al., 2000; Richardson and Thomson, 2002). The presence of most other 
species has generally only been described relative to the entire 
continental shelf zone (0-656 ft, 0-200 m) or beyond. Sounds produced 
by the drilling vessel and the seismic airguns are expected to drop 
below 120 dB and 160 dB, respectively, within the nearshore zone (0-131 
ft, 0-40 m, water depth) while sounds produced by ice management/
icebreaking activities, if they are necessary, are likely to also be 
present in the outer continental shelf (131-656 ft, 40-200 m).
    In addition to water depth, densities of marine mammals are likely 
to vary with the presence or absence of sea ice (see later for 
descriptions by species). At times during either summer or fall, pack-
ice may be present in some of the area around the drilling operation. 
However, the retreat of sea ice in the Alaskan Beaufort Sea has been 
substantial in recent years, so Shell has assumed that only 33% of the 
area exposed to sounds >=120 dB or >=160 dB by the proposed activities 
will be in ice margin habitat. Therefore, ice-margin densities of 
marine mammals in both seasons have been multiplied by 33% of the area 
exposed to sounds by the drilling vessel and ZVSP activities, while 
open-water (nearshore) densities have been multiplied by the remaining 
67% of the area.
    To provide some allowance for the uncertainties, ``maximum 
estimates'' as well as ``average estimates'' of the numbers of marine 
mammals potentially affected have been derived. For a few marine mammal 
species, several density estimates were available, and in those cases 
the mean and maximum estimates were determined from the survey data. In 
other cases, no applicable estimate (or perhaps a single estimate) was 
available, so correction factors were used to arrive at ``average'' and 
``maximum'' estimates. These are described in detail in the following 
subsections. NMFS has determined that the average density data of 
marine mammal populations will be used to calculate estimated take 
numbers because these numbers are based on surveys and monitoring of 
marine mammals in the vicinity of the proposed project area. Table 6-12 
in Shell's application indicates that the ``average estimate'' for gray 
whales, harbor porpoise, and ribbon seal is zero. Therefore, to account 
for the fact that these species listed as being potentially taken by 
harassment in this document may occur in Shell's proposed drilling 
sites during active operations, NMFS either used the ``maximum 
estimates'' or made an estimate based on typical group size for a 
particular species.
    Detectability bias, quantified in part by f(0), is associated with 
diminishing sightability with increasing lateral distance from the 
trackline. Availability bias [g(0)] refers to the fact that there is 
<100% probability of sighting an animal that is present along the 
survey trackline. Some sources of densities used below included these 
correction factors in their reported densities. In other cases the best 
available correction factors were applied to reported results when they 
had not been included in the reported data (e.g., Moore et al., 2000).
(1) Cetaceans
    As noted above, the densities of beluga and bowhead whales present 
in the Beaufort Sea are expected to vary by season and location. During 
the early and mid-summer, most belugas and bowheads are found in the 
Canadian Beaufort Sea and Amundsen Gulf or adjacent areas. Low numbers 
are found in the eastern Alaskan Beaufort Sea. Belugas begin to move 
across the Alaskan Beaufort Sea in August, and bowheads do so toward 
the end of August.
    Beluga Whales--Summer beluga density estimates were derived from 
survey data in Moore et al. (2000). During the summer, beluga whales 
are most likely to be encountered in offshore waters of the eastern 
Alaskan Beaufort Sea or areas with pack ice. The summer beluga whale 
nearshore density (Table 6-1 in Shell's application and Table 2 here) 
was based on 7,447 mi (11,985 km) of on-transect effort and nine 
associated sightings that occurred in water <=164 ft (50 m) in Moore et 
al. (2000). A mean group size of 1.63, a f(0) value of 2.841, and a 
g(0) value of 0.58 from Harwood et al. (1996) were also used in the 
calculation. Moore et al. (2000) found that belugas were equally likely 
to occur in heavy ice conditions as open-water or very light ice 
conditions in summer in the Beaufort Sea, so the same density was used 
for both nearshore and ice-margin estimates (Table 6-1 in Shell's 
application and Table 2 here). The fall beluga whale nearshore density 
was calculated by using 8,808 mi (14,175 km) of on-transect effort and 
seven associated sightings that occurred in Bowhead Whale Aerial Survey 
Program (BWASP) survey blocks 1, 4, and 5 in 2006-2009 (Clarke et al., 
2011a,b; pers. comm. J. Clarke and M. Ferguson, 2011). A mean group 
size of 2.9 (CV = 1.9), calculated from those 7 reported sightings, 
along with the same f(0) and g(0) values from Harwood et al. (1996), 
were used in the density calculation. Moore et al. (2000) found that 
during the fall in the Beaufort Sea belugas occurred in moderate to 
heavy ice at higher rates than in light ice, so ice-margin densities 
were estimated to be twice the nearshore densities. Based on the CV of 
group size maximum estimates in both season and habitats were estimated 
as four times the average estimates. ``Takes by harassment'' of beluga 
whales during the fall in the Beaufort Sea were not calculated in the 
same manner as described for bowhead whales because of the relatively 
lower expected densities of beluga whales in nearshore habitat near the 
exploration drilling program and the lack of detailed data on the 
likely timing and rate of migration through the area.

[[Page 69009]]

[GRAPHIC] [TIFF OMITTED] TN07NO11.000

    Bowhead Whales--Eastward migrating bowhead whales were recorded 
during industry aerial surveys of the continental shelf near Camden Bay 
in 2008 until July 12 (Christie et al., 2010). No bowhead sightings 
were recorded again, despite continued flights until August 19. Aerial 
surveys by industry operators did not begin until late August of 2006 
and 2007, but in both years bowheads were also recorded in the region 
before the end of August (Lyons et al., 2009). The late August 
sightings were likely of bowheads beginning their fall migration, so 
the densities calculated from those surveys were not used to estimate 
summer densities in this region. The three surveys in July 2008, 
resulted in density estimates of 0.0038, 0.0277, and 0.0072 bowhead 
whales/mi\2\ (0.0099, 0.0717, and 0.0186 whales/km\2\), respectively 
(Christie et al., 2010). The estimate of 0.0072 bowhead whales/mi\2\ 
(0.0186 whales/km\2\) was used as the average summer nearshore density, 
and the estimate of 0.0277 bowhead whales/mi\2\ (0.0717 whales/km\2\) 
was used as the maximum (see Table 6-1 in Shell's application and Table 
2 here). Sea ice was not present during these surveys. Moore et al. 
(2000) reported that bowhead whales in the Alaskan Beaufort Sea were 
distributed uniformly relative to sea ice, so the same nearshore 
densities were used for ice-margin habitat.
    During the fall, most bowhead whales will be migrating west past 
the exploration drilling program, so it is less accurate to assume that 
the number of individuals present in the area from one day to the next 
will be static. However, feeding, resting, and milling behaviors are 
not entirely uncommon at this time and location. In order to 
incorporate the movement of whales past the planned operations, and 
because the necessary data are available, Shell developed an alternate 
method of calculating the number of individual bowheads exposed to 
sounds produced by the exploration drilling program from the method 
used to calculate the number of exposures for bowheads in summer and 
the other marine mammal species for the entire season. The method is 
founded on estimates of the proportion of the population that would 
pass within the =120 dB or =160 dB zones on a 
given day in the fall during the exploration drilling or ZVSP surveys.
    Based on data in Richardson and Thomson (2002), the number of 
whales expected to pass each day after conclusion of the bowhead 
subsistence hunts (assumed to be September 15 for purposes of these 
calculations) was estimated as a proportion of the estimated 2012 
bowhead whale population. The number of whales passing each day was 
based on the 10-day moving average presented by Richardson and Thomson 
(2002; Appendix 9.1). Richardson and Thomson (2002) also calculated the 
proportion of animals within water depth bins (<66 ft [20 m], 66-131 ft 
[20-40 m], 131-656 ft [40-200 m], >656 ft [200 m]). Using this 
information, Shell multiplied the total number of whales expected to 
pass the exploration drilling program each day by the proportion of 
whales that would be in each depth category to estimate how many 
individuals would be within each depth bin on a given day. The 
proportion of each depth bin falling within the >=120 dB zone was then 
multiplied by the number of whales within the respective bins to 
estimate the total number of individuals that would be exposed on each 
day of exploration drilling or program activity, if they showed no 
avoidance of the operations. Based on the fact that most bowhead whales 
will be engaged in the fall migration at this time, NMFS determined 
that this method was appropriate for estimating the number of 
individual bowhead whales that may be exposed to drilling sounds after 
September 15.
    Exploration drilling will be suspended on August 25 prior to the 
start of the bowhead subsistence hunts at Kaktovik and Nuiqsut (Cross 
Island) and will be resumed when the hunts are concluded. After the 
completion of the subsistence hunts (for purposes of these calculations 
this was assumed to be September 15), exploration drilling activity 
would resume and continue as late as October 31. Therefore, the daily 
calculations described above were repeated for all days from September 
15 to October 31, and the results were summed to estimate the total 
number of bowhead whales that might be exposed to either continuous 
sounds >=120 dB rms from exploration drilling or icebreaking activities 
and impulsive sounds >=160 dB rms from ZVSP surveys during the 
migration period in the Beaufort Sea.
    The 2012 bowhead whale population size would be approximately 
15,232 individuals based on a 2001 population of 10,545 (Zeh and Punt, 
2005) and a continued annual growth rate of 3.4% (Allen and Angliss, 
2011). The estimated population size of 15,232 was therefore used by 
Shell as the foundation of the calculations of exposures during the 
migration period. The estimate of the proportion of the population 
passing the exploration drilling operation on each day is based on a 
10-day moving average, and the calculations have been made over a 
substantial length of time, so it would take significant variation in 
the timing

[[Page 69010]]

or nature of the migration to substantially deviate from the estimate 
calculated in this manner. Nonetheless, if a large portion of the 
migration were to be delayed or otherwise distributed closer to the 
area of the exploration drilling operations, more than the estimated 
number of whales could be exposed. Therefore, a maximum estimate of 2 
times the average estimate has been calculated, although it is unlikely 
that a substantial enough variation in the migration timing and 
location would cause such an increase in the number of whales present 
near the operations. If the hunts at Kaktovik and Cross Island 
(Nuiqsut) end later than September 15, then the number of exposures 
calculated by Shell would be an overestimate, as Shell would still need 
to end active operations by October 31 because of the increased chance 
of additional ice covering the drill sites later in the season.
    Gray Whales--For gray whales, densities are likely to vary somewhat 
by season, but differences are not expected to be great enough to 
require estimation of separate densities for the two seasons. Gray 
whales are not expected to be present in large numbers in the Beaufort 
Sea during the fall but small numbers may be encountered during the 
summer. They are most likely to be present in nearshore waters. Since 
this species occurs infrequently in the Beaufort Sea, little to no data 
are available for the calculation of densities. Minimal densities have 
therefore been assigned for calculation purpose and to allow for chance 
encounters (see Table 6-2 in Shell's application and Table 3 here). 
This table includes density estimates for additional cetacean species; 
however, for reasons mentioned earlier in this document are not 
considered for authorization by NMFS.
(2) Pinnipeds
    Extensive surveys of ringed and bearded seals have been conducted 
in the Beaufort Sea, but most surveys have been conducted over the 
landfast ice, and few seal surveys have occurred in open-water or in 
the pack ice. Kingsley (1986) conducted ringed seal surveys of the 
offshore pack ice in the central and eastern Beaufort Sea during late 
spring (late June). These surveys provide the most relevant information 
on densities of ringed seals in the ice margin zone of the Beaufort 
Sea. The density estimate in Kingsley (1986) was used as the average 
density of ringed seals that may be encountered in the ice margin 
(Table 6-2 in Shell's application and Table 3 here). The average ringed 
seal density in the nearshore zone of the Alaskan Beaufort Sea was 
estimated from results of ship-based surveys at times without seismic 
operations reported by Moulton and Lawson (2002; Table 6-2 in Shell's 
application and Table 3 here).
    Densities of bearded seals were estimated by multiplying the ringed 
seal densities by 0.051 based on the proportion of bearded seals to 
ringed seals reported in Stirling et al. (1982; Table 6-2 in Shell's 
application and Table 3 here). Spotted seal densities in the nearshore 
zone were estimated by summing the ringed seal and bearded seal 
densities and multiplying the result by 0.015 based on the proportion 
of spotted seals to ringed plus bearded seals reported in Moulton and 
Lawson (2002; Table 6-2 in Shell's application and Table 3 here). 
Minimal values were assigned as densities in the ice-margin zones 
(Table 6-2 in Shell's application and Table 3 here). This table also 
includes density estimates for ribbon seals; however, due to their 
rarity in the area, this species is not considered for authorization by 
NMFS.
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[[Page 69011]]



Estimated Area Exposed to Sounds >120 dB or >160 dB re 1 [mu]Pa rms

(1) Estimated Area Exposed to Continuous Sounds >=120 dB rms From the 
Drillship
    Shell proposes that exploration drilling in Camden Bay would be 
conducted from either the Kulluk or the Discoverer but not both. The 
two vessels are likely to introduce somewhat different levels of sound 
into the water during exploration drilling activities. Descriptions of 
the expected source levels and propagation distances from the two 
vessels are provided in this section. These distances and associated 
ensonified areas are then used in the following section to calculate 
separate estimates of potential exposures.
    Sounds from the Kulluk were measured in the Beaufort Sea in 1986 
and reported by Greene (1987a). The back propagated broadband source 
level from the measurements (185.5 dB re 1 [mu]Pa  m rms; 
calculated from the reported 1/3-octave band levels), which included 
sounds from a support vessel operating nearby, were used to model sound 
propagation at the Sivulliq prospect near Camden Bay. The model 
estimated that sounds would decrease to 120 dB rms at approximately 
8.25 mi (13.27 km) from the Kulluk (JASCO 2007; see Table 6-3 in 
Shell's application and Table 4 here). As a precautionary approach, 
Shell multiplied that distance by 1.5, and the resulting radius of 
12.37 mi (19.91 km) was used to estimate the total area that may be 
exposed to continuous sounds >=120 dB re 1 [mu]Pa rms by the Kulluk at 
each drill site. Assuming one well site will be drilled in each season 
(summer and fall), the total area of water ensonified to >=120 dB rms 
in each season would be 481 mi\2\ (1,245 km\2\).
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    Sounds from the Discoverer have not previously been measured in the 
Arctic. However, measurements of sounds produced by the Discoverer were 
made in the South China Sea in 2009 (Austin and Warner, 2010). The 
results of those measurements were used to model the sound propagation 
from the Discoverer (including a nearby support vessel) at planned 
exploration drilling locations in the Chukchi and Beaufort seas (Warner 
and Hannay, 2011). Broadband source levels of sounds produced by the 
Discoverer varied by activity and direction from the ship but were 
generally between 177 and 185 dB re 1 [mu]Pa  m rms (Austin and 
Warner, 2010). Propagation modeling at the Sivulliq and Torpedo 
prospects yielded somewhat different results, with sounds expected to 
propagate shorter distances at the Sivulliq site (Warner and Hannay, 
2011). As a precautionary approach, Shell used the larger distance to 
which sounds >=120 dB (2.06 mi [3.32 km]) are expected to propagate at 
the Torpedo site to estimate the area of water potentially exposed at 
both locations. The estimated (2.06 mi [3.32 km]) distance was 
multiplied by 1.5 (= 3.09 mi [4.98 km]) as a further precautionary 
measure before calculating the total area that may be exposed to 
continuous sounds >=120 dB re 1 [mu]Pa rms by the Discoverer at each 
drill site (see Table 6-3 in Shell's application and Table 4 here). 
Assuming one well would be drilled in each season (summer and fall), 
the total area of water ensonified to >=120 dB rms in each season would 
be 30 mi\2\ (78 km\2\). The 160-dB radii for the Kulluk and the 
Discoverer were estimated to be approximately 180 ft (55 m) and 33 ft 
(10 m), respectively. Again, because source levels for the two 
drillships were measured to be between 177 and 185 dB, the 180 and 190-
dB radii were not needed.
    The acoustic propagation model used to estimate the sound 
propagation from both vessels in Camden Bay is JASCO's Marine 
Operations Noise Model (MONM). MONM computes received sound levels in 
rms units when source levels are specified also in those units. MONM 
treats sound propagation in range-varying acoustic environments through 
a wide-angled parabolic equation solution to the acoustic wave 
equation. The specific parabolic equation code in MONM is based on the 
Naval Research Laboratory's Range-dependent Acoustic Model. This code 
has been extensively benchmarked for accuracy and is widely employed in 
the underwater acoustics community (Collins, 1993).
    For analysis of the potential effects on migrating bowhead whales 
Shell calculated the total distance perpendicular to the east-west 
migration corridor ensonified to >=120 dB rms in order to determine the 
number of migrating whales passing the activities that might be exposed 
to that sound level. For the Kulluk, that distance is 2 x 12.4 mi (19.9 
km) (the estimated radius of the 120 dB rms zone), or 24.7 mi (39.8 km) 
(i.e. 12.4 mi [19.9 km] north and 12.4 mi [19.9 km] south of the drill 
site); for the Discoverer, that distance is 2 x 3.09 mi, or 6.19 mi, 
(4.98 km or 9.96 km). At the two Sivulliq sites (G and N, which are 
located close together and positioned similarly relative to the 131 and 
656 ft [40 and 200 m] bathymetric contours), the 24.7 mi (39.8 km) 
distance from the Kulluk covers all of the 23 mi (37 km) wide 0-131 ft 
(0-40 m) water depth category, and approximately 11% of the 22.1 mi 
(35.5 km) wide 131-656 ft (40-200 m) water depth category. The 9.96 km 
distance from the Discoverer covers 27% of the 0-131 ft (0-40 m) 
category and none of the 131-656 ft (40-200 m) category at the Sivulliq 
sites.
    The two drill sites on the Torpedo prospect (designated as H and J) 
are not as close together as the Sivulliq sites, but their position 
relative to the 131 ft (40 m) and 656 ft (200 m) bathymetric contours 
are similar. For simplicity, Shell provided and used only the slightly 
greater estimates resulting from

[[Page 69012]]

calculations at the Torpedo ``H'' site to represent activities at 
either of the two Torpedo sites. At the Torpedo ``H'' site, the 24.7 mi 
(39.8 km) distance from the Kulluk covers approximately 74% of the 37 
km wide 0-131 ft (0-40 m) water depth category and approximately 35% of 
the 22.1 mi (35.5 km) wide 131-656 ft (40-200 m) water depth category. 
The 6.19 mi (9.96 km) distance from the Discoverer covers 27% of the 0-
131 ft (0-40 m) category and none of the 131-656 ft (40-200 m) category 
at either of the Torpedo sites.
    As described in the ``Basis for Estimating `Take by Harassment' '' 
subsection, the percentages of water depth categories described in the 
previous two paragraphs were multiplied by the estimated proportion of 
the whales passing within those categories on each day to estimate the 
number of bowheads that may be exposed to sounds >=120 dB if they 
showed no avoidance of the exploration drilling operations.
(2) Estimated Area Exposed to Continuous Sounds >=120 dB rms From Ice

Management/Icebreaking Activities

    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 [mu]Pa  m (Greene, 1987a; Richardson et al., 1995a). 
Measurements of the icebreaking sounds were made at five different 
distances and those were used to generate a propagation loss equation 
[RL=141.4 - 1.65R - 10Log(R) where R is range in kilometers (Greene, 
1987a); converting R to meters results in the following equation: R = 
171.4 - 10log(R) - 0.00165R]. Using that equation, the estimated 
distance to the 120 dB threshold for continuous sounds from icebreaking 
is 4.74 mi (7.63 km). Since the measurements of the Robert Lemeur were 
taken in the Beaufort Sea under presumably similar conditions as would 
be encountered in 2012, an inflation factor of 1.25 was selected to 
arrive at a precautionary 120 dB distance of 5.9 mi (9.5 km) for 
icebreaking sounds (see Table 6-3 in Shell's application and Table 4 
here).
    If ice is present, ice management/icebreaking activities may be 
necessary in early July and towards the end of operations in late 
October, but it is not expected to be needed throughout the proposed 
exploration drilling season. Icebreaking activities would likely occur 
in a 40[deg] arc up to 3.1 mi (5 km) upwind of the Kulluk or Discoverer 
(see Figure 1-3 and Attachment B in Shell's application for additional 
details). This activity area plus a 5.9 mi (9.5 km) buffer around it 
results in an estimated total area of 162 mi\2\ (420 km2) that may be 
exposed to sounds >=120 dB from ice management/icebreaking activities 
in each season. Icebreaking is not expected to occur during the bowhead 
migration since it is only anticipated to be needed either in early 
July or late October, so additional take estimates during the migration 
period have not been calculated.
(3) Estimated Area Exposed to Impulsive Sounds >=160 dB rms From 
Airguns
    Shell proposes to use the ITAGA eight-airgun array for the ZVSP 
surveys in 2012, which consists of four 150-in\3\ airguns and four 40-
in\3\ airguns for a total discharge volume of 760 in\3\. The >=160 dB 
re 1 [mu]Pa rms radius for this source was estimated from measurements 
of a similar seismic source used during the 2008 BP Liberty seismic 
survey (Aerts et al., 2008). The BP liberty source was also an eight-
airgun array but had a slightly larger total volume of 880 in\3\. 
Because the number of airguns is the same, and the difference in total 
volume only results in an estimated 0.4 dB decrease in the source level 
of the ZVSP source, the 100th percentile propagation model from the 
measurements of the BP Liberty source is almost directly applicable. 
However, the BP Liberty source was towed at a depth of 5.9 ft (1.8 m), 
while Shell's ZVSP source would be lowered to a target depth of 13 ft 
(4 m) (from 10-23 ft [3-7 m]). The deeper depth of the ZVSP source has 
the potential to increase the source strength by as much as 6 dB. Thus, 
the constant term in the propagation equation from the BP Liberty 
source was increased from 235.4 to 241.4 while the remainder of the 
equation (-18*LogR--0.0047*R) was left unchanged. NMFS reviewed the use 
of this equation and the similarities between the 2008 BP Liberty 
project and Shell's proposed drilling sites and determined that it is 
appropriate to base the sound isopleths on those results. This equation 
results in the following estimated distances to maximum received 
levels: 190 dB = 0.33 mi (524 m); 180 dB = 0.77 mi (1,240 m); 160 dB = 
2.28 mi (3,670 m); 120 dB = 6.52 mi (10,500 m). The >=160 dB distance 
was multiplied by 1.5 (see Table 6-3 in Shell's application and Table 4 
here) for use in estimating the area ensonified to >=160 dB rms around 
the drilling vessel during ZVSP activities. Therefore, the total area 
of water potentially exposed to received sound levels >=160 dB rms by 
ZVSP operations at one exploration well sites during each season is 
estimated to be 73.7 mi \2\ (190.8 km \2\).
    For analysis of potential effects on migrating bowhead whales, the 
>=120 dB distance for exploration drilling activities was used on all 
days during the bowhead migration as described previously. This is a 
precautionary approach in the case of the Kulluk since the >=160 dB 
zone for the relatively brief ZVSP surveys is expected to be less than 
the >=120 dB distance from the Kulluk. If the Discoverer were to be 
used, the slightly greater distance to the >=160 dB threshold from the 
ZVSP airguns than the >=120 dB distance from the Discoverer (see Table 
6-3 in Shell's application and Table 3 here) would result in only 3% 
more of the 0-131 ft (0-40 m) depth category being ensonified on up to 
2 days. This would result in an estimated increase of approximately 10 
bowhead whales compared to the estimates shown in (see Table 6-7 in 
Shell's application).
    Shell intends to conduct sound propagation measurements on the 
Kulluk or Discoverer (whichever is used) and the airgun source in 2012 
once they are on location near Camden Bay. The results of those 
measurements would then be used during the season to implement 
mitigation measures.

Potential Number of ``Takes by Harassment''

    Although a marine mammal may be exposed to drilling or icebreaking 
sounds >=120 dB (rms) or airgun sounds >=160 dB (rms), this does not 
mean that it will actually exhibit a disruption of behavioral patterns 
in response to the sound source. Rather, the estimates provided here 
are simply the best estimates of the number of animals that potentially 
could have a behavioral modification due to the noise. However, not all 
animals react to sounds at this low level, and many will not show 
strong reactions (and in some cases any reaction) until sounds are much 
stronger. There are several variables that determine whether or not an 
individual animal will exhibit a response to the sound, such as the age 
of the animal, previous exposure to this type of anthropogenic sound, 
habituation, etc.
    Numbers of marine mammals that might be present and potentially 
disturbed (i.e., Level B harassment) are estimated below based on 
available data about mammal distribution and densities at different 
locations and times of the year as described previously. Exposure 
estimates have been calculated based on the use of either the Kulluk or 
Discoverer operating in Camden Bay beginning in July, as well

[[Page 69013]]

as ice management/icebreaking activities, if needed, and minimal airgun 
usage (see estimates below). Shell will not conduct any activities 
associated with the exploration drilling program in Camden Bay during 
the 2012 Kaktovik and Nuiqsut (Cross Island) fall bowhead whale 
subsistence harvests. Shell will suspend exploration activities on 
August 25, prior to the beginning of the hunts, will resume activities 
in Camden Bay after conclusion of the subsistence harvests, and 
complete exploration activities on or about October 31, 2012. Actual 
drilling may occur on approximately 78 days in Camden Bay (which 
includes the 20-28 hours total needed for airgun operations), 
approximately half of which would occur before and after the fall 
bowhead subsistence hunts.
    The number of different individuals of each species potentially 
exposed to received levels of continuous sound >=120 dB re 1 [mu]Pa 
(rms) or to pulsed sounds >=160 dB re 1 [mu]Pa (rms) within each season 
and habitat zone was estimated by multiplying:
     The anticipated area to be ensonified to the specified 
level in the time period and habitat zone to which a density applies, 
by
     The expected species density.
    The estimate for bowhead whales during the migration period was 
calculated differently as described previously. The numbers of 
exposures were then summed for each species across the seasons and 
habitat zones.
    At times during either summer (July-August) or fall (September-
October), pack-ice may be present in some of the area around the 
exploration drilling operation. However, the retreat of sea ice in the 
Alaskan Beaufort Sea has been substantial in recent years, so Shell 
assumed that only 33% of the area exposed to sounds >=120 dB or >=160 
dB by the exploration drilling program and ZVSP activities will be in 
ice-margin habitat. Therefore, ice-margin densities of marine mammals 
in both seasons have been multiplied by 33% of the area exposed to 
sounds by the drilling and ZVSP activities, while open-water 
(nearshore) densities have been multiplied by the remaining 67% of the 
area. Since any icebreaking activities would only occur in ice-margin 
habitat, the entire area exposed to sounds >=120 dB from icebreaking 
was multiplied by the ice-margin densities.
(1) Cetaceans
    Cetacean species potentially exposed to exploration drilling or 
icebreaking sounds with continuous received levels >=120 dB rms or 
airgun sounds >=160 dB rms may include both mysticetes (bowhead and 
gray whales) and odontocetes (beluga whale). Separate estimates for 
beluga and bowhead whales are provided based on whether the Kulluk (see 
Table 6-4 in Shell's application or Table 5 here) or the Discoverer 
(see Table 6-5 in Shell's application or Table 6 here) is used as the 
drilling vessel in 2012. The results presented in those two tables 
should not be summed, as the operations will only be conducted from one 
of the drilling vessels. Estimates from icebreaking activities, should 
these occur, are shown in Table 6-6 in Shell's application or Table 7 
here. Estimates of exposure to airgun pulses from ZVSP activities are 
provided in Table 6-7 and Table 8 here.
    If the Kulluk is used, the average estimates of the number of 
individual belugas and bowheads exposed to continuous sounds >=120 dB 
from exploration drilling activities during both summer and fall are 10 
and 5,598, respectively (Table 6-4 in Shell's application or Table 5 
here). The smaller size of the expected >=120 dB zone around the 
Discoverer resulted in an average estimate of 0 and 1,388 beluga and 
bowhead whales potentially being exposed to sounds >=120 dB during 
summer and fall, respectively (Table 6-5 in Shell's application and 
Table 6 here). Should icebreaking activities occur in both seasons, an 
additional 4 beluga and 8 bowhead whales may be exposed to continuous 
received sounds >=120 dB (Table 6-6 in Shell's application and Table 7 
here). Because of the relatively small airgun source and short duration 
of the ZVSP surveys, they are not expected to contribute substantially 
to the estimated number of belugas and bowheads exposed by the 
activities (Table 6-7 in Shell's application and Table 8 here). The 
estimated exposure of bowheads to these sounds during the migration has 
already been included in the estimates for the Kulluk (e.g., take of 10 
belugas and 5,598 bowheads). The slightly greater distance to the >=160 
dB threshold from the ZVSP airguns than the >=120 dB distance from the 
Discoverer would result in only 3% more of the 0-131 ft (0-40 m) depth 
category being ensonified on up to 2 days. This would result in an 
estimated increase of approximately 10 bowhead whales from ZVSP 
activities compared to the estimate shown in (Table 6-5 in Shell's 
application and Table 6 here).
    Few other cetaceans are likely to be present in the area of the 
planned operations and the very small estimated densities for those 
species were not large enough for the calculations to result in 
estimates >1% from the Kulluk (Table 6-8 in Shell's application and 
Table 9 here), Discoverer (Table 6-9 in Shell's application and Table 
10 here), icebreaking activities (Table 6-10 in Shell's application and 
Table 11 here), or ZVSP activities (Table 6-11 in Shell's application 
and Table 12 here).
(2) Seals
    The ringed seal is the most widespread and abundant pinniped in 
ice-covered arctic waters, and there appears to be a great deal of 
year-to-year variation in abundance and distribution of these marine 
mammals. As a result of their high abundance, ringed seals account for 
a large number of marine mammals expected to be encountered during the 
exploration drilling program and hence exposed to sounds with received 
levels >=120 dB or >=160 dB rms. If the Kulluk is used, calculations 
based on the average density result in an estimate of 798 ringed seals 
that might be exposed during summer and fall to sounds with received 
levels >=120 dB from the exploration drilling program (Table 6-8 in 
Shell's application and Table 9 here). Should the Discoverer be used, 
the estimated number of ringed seals exposed to >=120 dB during summer 
and fall is 49 (Table 6-9 in Shell's application and Table 10 here). If 
ice management/icebreaking occurred during both seasons, an additional 
211 ringed seals may be exposed to continuous sounds >=120 dB (Table 6-
10 in Shell's application and Table 11 here). The ZVSP activities are 
estimated to expose 60 ringed seals to pulsed airgun sounds >=160 dB 
(Table 6-11 in Shell's application and Table 12 here).
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BILLING CODE 3510-22-C
    Two additional seal species are expected to be encountered with 
lower frequency than ringed seals. Estimates based on average densities 
of bearded seals and spotted seals are 41 and 6, respectively, during 
summer and fall if the exploration drilling program is conducted by the 
Kulluk (Table 6-8 in Shell's application and Table 9 here). If the 
Discoverer is used, the estimates are reduced to 3 and 0 for bearded 
and spotted seals, respectively (Table 6-9 in Shell's application and 
Table 10 here). Should icebreaking occur in both seasons an additional 
11 bearded seals may be exposed to continuous sounds with received 
levels >=120 dB (Table 6-10 in Shell's application and Table 11 here). 
Exposures of individuals from either species to sound levels >=160 dB 
from the ZVSP activities are expected to be quite low due to the 
relative small area expected to be exposed to those sounds (Table 6-11 
in Shell's application and Table 12 here). Although only sighted on 
occasion, ribbon seals may occur in the area, so Shell provided 
estimates for this species as well.

Estimated Take Conclusions

    As stated previously, NMFS' practice has been to apply the 120 dB 
re 1 [micro]Pa (rms) received level threshold for underwater continuous 
sound levels and the 160 dB re 1 [micro]Pa (rms) received level 
threshold for underwater impulsive sound levels to determine whether 
take by Level B harassment occurs. However, not all animals react to 
sounds at these low levels, and many

[[Page 69018]]

will not show strong reactions (and in some cases any reaction) until 
sounds are much stronger. Southall et al. (2007) provide a severity 
scale for ranking observed behavioral responses of both free-ranging 
marine mammals and laboratory subjects to various types of 
anthropogenic sound (see Table 4 in Southall et al. (2007)). Tables 15, 
17, and 21 in Southall et al. (2007) outline the numbers of low-
frequency and mid-frequency cetaceans and pinnipeds in water, 
respectively, reported as having behavioral responses to non-pulses in 
10-dB received level increments. These tables illustrate, especially 
for low- and mid-frequency cetaceans, that more intense observed 
behavioral responses did not occur until sounds were higher than 120 dB 
(rms). Many of the animals had no observable response at all when 
exposed to anthropogenic continuous sound at levels of 120 dB (rms) or 
even higher.
    Although the 120-dB isopleth for the drillships may seem fairly 
expansive (i.e., 12.37 mi [19.91 km] for the Kulluk or 4.6 mi [7.4 km] 
for the Discoverer, which include the 50 percent inflation factor), the 
zone of ensonification begins to shrink dramatically with each 10-dB 
increase in received sound level. The 160-dB rms zones for the Kulluk 
and Discoverer are estimated to extend approximately 180 ft (55 m) and 
33 ft (10 m) for the ship, respectively. As stated previously, source 
levels for the two different drillships are expected to be between 177 
and 185 dB (rms). For an animal to be exposed to received levels 
between 177 and 185 dB, it would have to be within several meters of 
the vessel, which is unlikely, especially give the fact that certain 
species are likely to avoid the area (as described earlier in this 
document).
    For impulsive sounds, such as those produced by the airguns, 
studies reveal that baleen whales show avoidance responses, which would 
reduce the likelihood of them being exposed to higher received sound 
levels. The 180-dB zone (0.77 mi [1.24 km]) is one-third the size of 
the 160-dB zone (2.28 mi [3.67 km], which is the modeled distance 
before the 1.5 inflation factor is included). In the limited studies 
that have been conducted on pinniped responses to pulsed sound sources, 
they seem to be more tolerant and do not exhibit strong behavioral 
reactions (see Southall et al., 2007).
    NMFS is proposing to authorize the average take estimates provided 
in Table 6-12 of Shell's application and Table 13 here for bowhead 
whales and bearded, ringed, and spotted seals. The only exceptions to 
this are for the gray whale, harbor porpoise, and ribbon seal since the 
average estimate is zero for those species and for the beluga whale to 
account for group size. Therefore, for the 2012 Beaufort Sea drilling 
season, NMFS proposes to authorize the take of 38 beluga whales, 5,608 
bowhead whales, 15 gray whales, 15 harbor porpoise, 55 bearded seals, 
1,069 ringed seals, 7 spotted seals, and 5 ribbon seals. For beluga and 
gray whales and harbor porpoise, this represents 0.1% of the Beaufort 
Sea population of approximately 39,258 beluga whales (Allen and 
Angliss, 2011), 0.08% of the Eastern North Pacific stock of 
approximately 18,017 gray whales (Allen and Angliss, 2011), and 0.03% 
of the Bering Sea stock of approximately 48,215 harbor porpoise (Allen 
and Angliss, 2011). This also represents 36.8% of the Bering-Chukchi-
Beaufort bowhead population of 15,232 individuals assuming 3.4% annual 
population growth from the 2001 estimate of 10,545 animals (Zeh and 
Punt, 2005). The take estimates presented for bearded, ringed, and 
spotted seals represent 0.02%, 0.4%, and 0.01% of the Bering-Chukchi-
Beaufort populations for each species, respectively. The take estimate 
for ribbon seals represents 0.01% of the Alaska stock of this species. 
These proposed take numbers are based on Shell utilizing the Kulluk. 
Table 13 here also presents the take numbers and percentages of the 
population if Shell utilizes the Discoverer instead, which has a 
smaller 120-dB radius. If the Discoverer is used for drilling 
operations instead of the Kulluk, the take estimates for bowhead whales 
and ringed and bearded seals drop substantially.
    With the exception of the subsistence mitigation measure of 
shutting down during the Nuiqsut and Kaktovik fall bowhead whale hunts, 
these take estimates do not take into account any of the mitigation 
measures described previously in this document. Additionally, if the 
fall bowhead hunts end after September 15, and Shell still concludes 
activities on October 31, then fewer animals will be exposed to 
drilling sounds, especially bowhead whales, as more of them will have 
migrated past the area in which they would be exposed to continuous 
sound levels of 120 dB or greater or impulsive sound levels of 160 dB 
or greater prior to Shell resuming active operations. These take 
numbers also do not consider how many of the exposed animals may 
actually respond or react to the proposed exploration drilling program. 
Instead, the take estimates are based on the presence of animals, 
regardless of whether or not they react or respond to the activities.

[[Page 69019]]

[GRAPHIC] [TIFF OMITTED] TN07NO11.007

Negligible Impact Analysis

    NMFS has defined ``negligible impact'' in 50 CFR 216.103 as ``* * * 
an impact resulting from the specified activity that cannot be 
reasonably expected to, and is not reasonably likely to, adversely 
affect the species or stock through effects on annual rates of 
recruitment or survival.'' In making a negligible impact determination, 
NMFS considers a variety of factors, including but not limited to: (1) 
The number of anticipated mortalities; (2) the number and nature of 
anticipated injuries; (3) the number, nature, intensity, and duration 
of Level B harassment; and (4) the context in which the takes occur.
    No injuries or mortalities are anticipated to occur as a result of 
Shell's proposed Camden Bay exploratory drilling program, and none are 
proposed to be authorized. Injury, serious injury, or mortality could 
occur if there were a large or very large oil spill. However, as 
discussed previously in this document, the likelihood of a spill is 
extremely remote. Shell has implemented many design and operational 
standards to mitigate the potential for an oil spill of any size. NMFS 
does not propose to authorize take from an oil spill, as it is not part 
of the specified activity. Additionally, animals in the area are not 
expected to incur hearing impairment (i.e., TTS or PTS) or non-auditory 
physiological effects. Instead, any impact that could result from 
Shell's activities is most likely to be behavioral harassment and is 
expected to be of limited duration. Although it is possible that some 
individuals may be exposed to sounds from drilling operations more than 
once, during the migratory periods it is less likely that this will 
occur since animals will continue to move westward across the Beaufort 
Sea. This is especially true for bowhead whales that will be migrating 
past the drilling operations beginning in mid- to late September 
(depending on the date Shell resumes activities after the shutdown 
period for the fall bowhead subsistence hunts by the villages of 
Kaktovik and Nuiqsut).
    Some studies have shown that bowhead whales will continue to feed 
in areas of seismic operations (e.g., Richardson, 2004). Therefore, it 
is possible that some bowheads may continue to feed in an area of 
active drilling operations. It is important to note that the sounds 
produced by drilling operations are of a much lower intensity than 
those produced by seismic airguns. Should bowheads choose to feed in 
the ensonified area instead of avoiding the sound, individuals may be 
exposed to sounds at or above 120 dB (rms) for several hours to days, 
depending on how long the individual animal chooses to remain in the 
area to feed. Should bowheads choose to feed in Camden Bay during the 
ZVSP surveys, this activity will occur only twice during the entire 
drilling season and will not last more than 10-14 hours each time. It 
is anticipated that one such survey would occur prior to the migration 
period and one during the migration period. Therefore, feeding or 
migrating bowhead whales would only be exposed to airgun sounds for a 
total of 10-14 hours throughout the entire open-water season. As noted 
previously, many animals perform vital functions, such as feeding, 
resting, traveling, and socializing on a diel cycle (24-hr cycle). As 
discussed here, some bowhead whales may decide to remain in Camden Bay 
for several days to feed; however, they are not expected to be feeding 
for 24 hours straight each day. While feeding in an area of increased 
anthropogenic sound may potentially result in increased stress, it is 
not anticipated that the level of sound produced by the exploratory 
drilling operations and the amount of time that an individual whale may 
remain in the area to feed would result in noise-induced physiological 
stress to the animal. Additionally, if an animal is excluded from 
Camden Bay for feeding because it decides to avoid the ensonified area, 
this may result in some extra energy expenditure for the animal to find 
an alternate feeding ground. However, Camden Bay is only one of a few 
feeding areas for bowhead whales in the U.S. Arctic Ocean. NMFS 
anticipates that bowhead whales could find feeding opportunities in 
other parts of the Beaufort Sea.
    Some bowhead whales have been observed feeding in the Camden Bay 
area in recent years, even though oil and gas activities have been 
occurring in the general region. There has also been recent evidence 
that some bowhead whales 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, they 
would be in areas where the sound levels are not high enough to cause 
injury (based on the fact that source levels are not expected to reach 
levels known to cause even slight, mild TTS,

[[Page 69020]]

a non-injurious threshold shift). Additionally, if bowhead whales come 
within the 180-dB (rms) radius when the airguns are operational, Shell 
will shutdown the airguns until the animals are outside of the required 
EZ. Although the impact resulting from the generation of sound may 
cause a disruption in feeding activities in and around Camden Bay, this 
disruption is not reasonably likely to adversely affect bowhead whales.
    Shell's proposed exploration drilling program is not expected to 
negatively affect the bowhead whale westward migration through the U.S. 
Beaufort Sea. The migration typically starts around the last week of 
August or first week of September. Shell has agreed to cease operations 
on August 25 for the fall bowhead whale hunts at Kaktovik and Cross 
Island (for the village of Nuiqsut). Operations will not resume until 
both communities have announced the close of the fall hunt, which 
typically occurs around September 15 each year. Therefore, whales that 
migrate through the area the first few weeks of the migration period 
will not be exposed to any acoustic or non-acoustic stimuli from 
Shell's proposed operations. Only the last 6 weeks of Shell's 
operations would occur during the migratory period. Cow/calf pairs 
typically migrate through the area later in the season (i.e., late 
September/October) as opposed to the beginning of the season (i.e., 
late August/early September). Shell's activities are not anticipated to 
have a negative effect on the migration or on the cow/calf pairs 
migrating through the area. If cow/calf pairs migrate through during 
airgun operations, power down and shutdown procedures are proposed to 
be required to reduce impacts further.
    Beluga whales are more likely to occur in the project area after 
the recommencement of activities in September than in July or August. 
Should any belugas occur in the area of active drilling, it is not 
expected that they would remain in the area for a prolonged period of 
time, as their westward migration usually occurs further offshore (more 
than 37 mi [60 km]) and in deeper waters (more than 656 ft [200 m]) 
than that planned for the location of Shell's Camden Bay well sites. 
Gray whales do not occur frequently in the Camden Bay area of the 
Beaufort Sea. Additionally, there are no known feeding grounds for gray 
whales in the Camden Bay area. The most northern feeding sites known 
for this species are located in the Chukchi Sea near Hanna Shoal and 
Point Barrow. Based on these factors, exposures of gray whales to 
industrial sound are not expected to last for prolonged periods (i.e., 
several days or weeks) since they are not known to remain in the area 
for extended periods of time. Since harbor porpoise are considered 
extralimital in the area with recent sightings not occurring east of 
Prudhoe Bay, no adverse impacts that could affect important life 
functions are anticipated for this species.
    Some individual pinnipeds may be exposed to drilling sounds more 
than once during the timeframe of the project. This may be especially 
true for ringed seals, which occur in the Beaufort Sea year-round and 
are the most frequently encountered pinniped species in the area. 
However, as stated previously in this document, pinnipeds appear to be 
more tolerant of anthropogenic sound, especially at lower received 
levels, than other marine mammals, such as mysticetes.
    Ringed seals construct lairs for pupping in the Beaufort Sea. 
However, this species typically does not construct lairs until late 
winter/early spring on the landfast ice. Because Shell will cease 
operations by October 31, they will not be in the area during the 
ringed seal pupping season. Bearded seals breed in the Bering and 
Chukchi Seas, as the Beaufort Sea provides less suitable habitat for 
the species. Spotted and ribbon seals are even less common in the 
Camden Bay area. These species do not breed in the Beaufort Sea. 
Shell's proposed exploration drilling program is not anticipated to 
impact breeding or pupping for any of the ice seal species.
    Of the eight marine mammal species likely to occur in the proposed 
drilling area, only the bowhead whale is listed as endangered under the 
ESA. The species is also designated as ``depleted'' under the MMPA. 
Despite these designations, the Bering-Chukchi-Beaufort stock of 
bowheads has been increasing at a rate of 3.4% annually for nearly a 
decade (Allen and Angliss, 2011), even in the face of ongoing 
industrial activity. Additionally, during the 2001 census, 121 calves 
were counted, which was the highest yet recorded. The calf count 
provides corroborating evidence for a healthy and increasing population 
(Allen and Angliss, 2011). Certain stocks or populations of gray and 
beluga whales and spotted seals are listed as endangered or are 
proposed for listing under the ESA; however, none of those stocks or 
populations occur in the proposed activity area. On December 10, 2010, 
NMFS published a notice of proposed threatened status for subspecies of 
the ringed seal (75 FR 77476) and a notice of proposed threatened and 
not warranted status for subspecies and distinct population segments of 
the bearded seal (75 FR 77496) in the Federal Register. Neither of 
these two ice seal species is currently considered depleted under the 
MMPA. There is currently no established critical habitat in the 
proposed project area for any of these eight species.
    Potential impacts to marine mammal habitat were discussed 
previously in this document (see the ``Anticipated Effects on Habitat'' 
section). Although some disturbance is possible to food sources of 
marine mammals, any impacts to affected marine mammal stocks or species 
are anticipated to be minor. Based on the vast size of the Arctic Ocean 
where feeding by marine mammals occurs versus the localized area of the 
drilling program, any missed feeding opportunities in the direct 
project area would be of little consequence, as marine mammals would 
have access to other feeding grounds.
    If the Kulluk is the drillship used, the estimated takes proposed 
to be authorized represent 0.1% of the Beaufort Sea population of 
approximately 39,258 beluga whales (Allen and Angliss, 2011), 0.08% of 
the Eastern North Pacific stock of approximately 18,017 gray whales 
(Allen and Angliss, 2011), 0.03% of the Bering Sea stock of 
approximately 48,215 harbor porpoise (Allen and Angliss, 2011), and 
36.8% of the Bering-Chukchi-Beaufort population of 15,232 individuals 
assuming 3.4% annual population growth from the 2001 estimate of 10,545 
animals (Zeh and Punt, 2005). The take estimates presented for bearded, 
ringed, and spotted seals represent 0.02%, 0.4%, and 0.01% of the 
Bering-Chukchi-Beaufort populations for each species, respectively. The 
take estimate for ribbon seals represents 0.01% of the Alaska stock of 
this species. If the Discoverer is the drillship used, the estimated 
takes proposed to be authorized represent 0.1% of the Beaufort Sea 
population of approximately 39,258 beluga whales (Allen and Angliss, 
2011), 0.08% of the Eastern North Pacific stock of approximately 18,017 
gray whales (Allen and Angliss, 2011), 0.03% of the Bering Sea stock of 
approximately 48,215 harbor porpoise (Allen and Angliss, 2011), and 
9.2% of the Bering-Chukchi-Beaufort population of 15,232 individuals 
assuming 3.4% annual population growth from the 2001 estimate of 10,545 
animals (Zeh and Punt, 2005). The take estimates presented for bearded, 
ringed, and spotted seals represent 0.01%, 0.1%, and 0.01% of the 
Bering-Chukchi-Beaufort populations for each species,

[[Page 69021]]

respectively. The take estimate for ribbon seals represents 0.01% of 
the Alaska stock of this species. These estimates represent the 
percentage of each species or stock that could be taken by Level B 
behavioral harassment if each animal is taken only once.
    The estimated take numbers are likely somewhat of an overestimate 
for several reasons. First, these take numbers were calculated using a 
50% inflation factor of the 120-dB and 160-dB radii, which is a 
conservative approach recommended by some acousticians when modeling a 
new sound source in a new location. SSV tests could reveal that the 
Level B harassment zone is either smaller or larger than that used to 
estimate take. If the SSV tests reveal that the Level B harassment 
zones are slightly larger than those modeled, the 50% inflation factor 
should cover the discrepancy, however, based on recent SSV tests of 
seismic airguns (which showed that the measured 160-dB isopleths was in 
the area of the modeled value), the 50% correction factor likely 
results in an overestimate of takes. Additionally, the mitigation and 
monitoring measures (described previously in this document) proposed 
for inclusion in the IHA (if issued) are expected to reduce even 
further any potential disturbance to marine mammals. Last, some marine 
mammal individuals, including mysticetes, have been shown to avoid the 
ensonified area around airguns at certain distances (Richardson et al., 
1999), and, therefore, some individuals would not likely enter into the 
Level B harassment zones for the various types of activities.
    The take estimates for the Kulluk are approximately four times 
those for the Discoverer. One explanation for this is that the Kulluk's 
original rigid structure does little to dampen vibration as it moves 
through the structure to the hull. The Kulluk's main engines are welded 
to the deck rather than being on vibration absorbing mounts, which may 
also contribute to the relatively higher sound level. This past year, 
Shell has invested in retrofitting the Kulluk. This retrofit includes 
changing out the engines and installing sound dampening mounts for the 
new engines. This retrofit is expected to help lower the sound levels 
emitted by the Kulluk. As stated previously, Shell intends to conduct 
SSV tests for all vessels, including the drillship, once on location in 
the Beaufort Sea in 2012. Therefore, there is the potential for the 
take estimates to be reduced even further.

Impact on Availability of Affected Species or Stock for Taking for 
Subsistence Uses

Relevant Subsistence Uses

    The disturbance and potential displacement of marine mammals by 
sounds from drilling activities are the principal concerns related to 
subsistence use of the area. Subsistence remains the basis for Alaska 
Native culture and community. Marine mammals are legally hunted in 
Alaskan waters by coastal Alaska Natives. In rural Alaska, subsistence 
activities are often central to many aspects of human existence, 
including patterns of family life, artistic expression, and community 
religious and celebratory activities. Additionally, the animals taken 
for subsistence provide a significant portion of the food that will 
last the community throughout the year. The main species that are 
hunted include bowhead and beluga whales, ringed, spotted, and bearded 
seals, walruses, and polar bears. (As mentioned previously in this 
document, both the walrus and the polar bear are under the USFWS' 
jurisdiction.) The importance of each of these species varies among the 
communities and is largely based on availability.
    The subsistence communities in the Beaufort Sea that have the 
potential to be impacted by Shell's Camden Bay drilling program include 
Kaktovik, Nuiqsut, and Barrow. Kaktovik is a coastal community 60 mi 
(96.6 km) east of the project area. Nuiqsut is 118 mi (190 km) west of 
the project area and about 20 mi (32 km) inland from the coast along 
the Colville River. Cross Island, from which Nuiqsut hunters base their 
bowhead whaling activities, is 47 mi (75.6 km) southwest of the project 
area. Barrow, the community farthest from the project area, lies 298 mi 
(479.6 km) west of Shell's Camden Bay drill sites.
(1) Bowhead Whales
    Of the three communities, Barrow is the only one that currently 
participates in a spring bowhead whale hunt. However, this hunt is not 
anticipated to be affected by Shell's activities, as the spring hunt 
occurs in late April to early May, and Shell's Camden Bay drilling 
program will not begin until July 10, at the earliest.
    All three communities participate in a fall bowhead hunt. In 
autumn, westward-migrating bowhead whales typically reach the Kaktovik 
and Cross Island (Nuiqsut hunters) areas by early September, at which 
points the hunts begin (Kaleak, 1996; Long, 1996; Galginaitis and 
Koski, 2002; Galginaitis and Funk, 2004, 2005; Koski et al., 2005). 
Around late August, the hunters from Nuiqsut establish camps on Cross 
Island from where they undertake the fall bowhead whale hunt. The 
hunting period starts normally in early September and may last as late 
as mid-October, depending mainly on ice and weather conditions and the 
success of the hunt. Most of the hunt occurs offshore in waters east, 
north, and northwest of Cross Island where bowheads migrate and not 
inside the barrier islands (Galginaitis, 2007). Hunters prefer to take 
bowheads close to shore to avoid a long tow, but Braund and Moorehead 
(1995) report that crews may (rarely) pursue whales as far as 50 mi (80 
km) offshore. Whaling crews use Kaktovik as their home base, leaving 
the village and returning on a daily basis. The core whaling area is 
within 12 mi (19.3 km) of the village with a periphery ranging about 8 
mi (13 km) farther, if necessary. The extreme limits of the Kaktovik 
whaling limit would be the middle of Camden Bay to the west. The timing 
of the Kaktovik bowhead whale hunt roughly parallels the Cross Island 
whale hunt (Impact Assessment Inc, 1990b; SRB&A, 2009:Map 64). In 
recent years, the hunts at Kaktovik and Cross Island have usually ended 
by mid- to late September.
    Westbound bowheads typically reach the Barrow area in mid-September 
and are in that area until late October (Brower, 1996). However, over 
the years, local residents report having seen a small number of bowhead 
whales feeding off Barrow or in the pack ice off Barrow during the 
summer. Recently, autumn bowhead whaling near Barrow has normally begun 
in mid-September to early October, but in earlier years it began as 
early as August if whales were observed and ice conditions were 
favorable (USDI/BLM, 2005). The recent decision to delay harvesting 
whales until mid-to-late September has been made to prevent spoilage, 
which might occur if whales were harvested earlier in the season when 
the temperatures tend to be warmer. Whaling near Barrow can continue 
into October, depending on the quota and conditions.
    Shell anticipates arriving on location in Camden Bay around July 10 
and continuing operations until August 25. Shell has stated that it 
will suspend all operations on August 25 for the Nuiqsut (Cross Island) 
and Kaktovik subsistence bowhead whale hunts. The drillship and support 
vessels will leave the Camden Bay project area, will move to a location 
at or north of 71.25[deg] N. latitude and at or west of 146.4[deg] W. 
longitude, and will return to resume activities after the Nuiqsut 
(Cross

[[Page 69022]]

Island) and Kaktovik bowhead hunts conclude. Depending on when Nuiqsut 
and Kaktovik declare their hunts closed, drilling operations may resume 
in the middle of the Barrow fall bowhead hunt.
(2) Beluga Whales
    Beluga whales are not a prevailing subsistence resource in the 
communities of Kaktovik and Nuiqsut. Kaktovik hunters may harvest one 
beluga whale in conjunction with the bowhead hunt; however, it appears 
that most households obtain beluga through exchanges with other 
communities. Although Nuiqsut hunters have not hunted belugas for many 
years while on Cross Island for the fall hunt, this does not mean that 
they may not return to this practice in the future. Data presented by 
Braund and Kruse (2009) indicate that only 1% of Barrow's total harvest 
between 1962 and 1982 was of beluga whales and that it did not account 
for any of the harvested animals between 1987 and 1989.
    There has been minimal harvest of beluga whales in Beaufort Sea 
villages in recent years. Additionally, if belugas are harvested, it is 
usually in conjunction with the fall bowhead harvest. Shell will not be 
operating during the Kaktovik and Nuiqsut fall bowhead harvests.
(3) Ice Seals
    Ringed seals are available to subsistence users in the Beaufort Sea 
year-round, but they are primarily hunted in the winter or spring due 
to the rich availability of other mammals in the summer. Bearded seals 
are primarily hunted during July in the Beaufort Sea; however, in 2007, 
bearded seals were harvested in the months of August and September at 
the mouth of the Colville River Delta. An annual bearded seal harvest 
occurs in the vicinity of Thetis Island (which is a considerable 
distance from Shell's proposed Camden Bay drill sites) in July through 
August. Approximately 20 bearded seals are harvested annually through 
this hunt. Spotted seals are harvested by some of the villages in the 
summer months. Nuiqsut hunters typically hunt spotted seals in the 
nearshore waters off the Colville River delta, which is more than 100 
mi (161 km) from Shell's proposed drill sites.
    Although there is the potential for some of the Beaufort villages 
to hunt ice seals during the summer and fall months while Shell is 
conducting exploratory drilling operations, the primary sealing months 
occur outside of Shell's operating time frame. Additionally, some of 
the more established seal hunts that do occur in the Beaufort Sea, such 
as the Colville delta area hunts, are located a significant distance 
(in some instances 100 mi [161 km] or more) from the proposed project 
area.

Potential Impacts to Subsistence Uses

    NMFS has defined ``unmitigable adverse impact'' in 50 CFR 216.103 
as an impact resulting from the specified activity that is likely to 
reduce the availability of the species to a level insufficient for a 
harvest to meet subsistence needs by causing the marine mammals to 
abandon or avoid hunting areas; directly displacing subsistence users; 
or placing physical barriers between the marine mammals and the 
subsistence hunters; and that cannot be sufficiently mitigated by other 
measures to increase the availability of marine mammals to allow 
subsistence needs to be met.
    Noise and general activity during Shell's proposed drilling program 
have the potential to impact marine mammals hunted by Native Alaskans. 
In the case of cetaceans, the most common reaction to anthropogenic 
sounds (as noted previously in this document) is avoidance of the 
ensonified area. In the case of bowhead whales, this often means that 
the animals divert from their normal migratory path by several 
kilometers. Helicopter activity also has the potential to disturb 
cetaceans and pinnipeds by causing them to vacate the area. 
Additionally, general vessel presence in the vicinity of traditional 
hunting areas could negatively impact a hunt. Native knowledge 
indicates that bowhead whales become increasingly ``skittish'' in the 
presence of seismic noise. Whales are more wary around the hunters and 
tend to expose a much smaller portion of their back when surfacing 
(which makes harvesting more difficult). Additionally, natives report 
that bowheads exhibit angry behaviors in the presence of seismic, such 
as tail-slapping, which translate to danger for nearby subsistence 
harvesters.
    In the case of subsistence hunts for bowhead whales in the Beaufort 
Sea, there could be an adverse impact on the hunt if the whales were 
deflected seaward (further from shore) in traditional hunting areas. 
The impact would be that whaling crews would have to travel greater 
distances to intercept westward migrating whales, thereby creating a 
safety hazard for whaling crews and/or limiting chances of successfully 
striking and landing bowheads.

Plan of Cooperation (POC)

    Regulations at 50 CFR 216.104(a)(12) require IHA applicants for 
activities that take place in Arctic waters to provide a POC or 
information that identifies what measures have been taken and/or will 
be taken to minimize adverse effects on the availability of marine 
mammals for subsistence purposes. Shell has developed a Draft POC for 
its 2012 Camden Bay, Beaufort Sea, Alaska, exploration drilling program 
to minimize any adverse impacts on the availability of marine mammals 
for subsistence uses. A copy of the Draft POC was provided to NMFS with 
the IHA Application as Attachment D (see ADDRESSES for availability). 
Meetings with potentially affected subsistence users began in 2009 and 
continued into 2010 and 2011 (see Table 4.2-1 in Shell's POC for a list 
of all meetings conducted through April 2011). During these meetings, 
Shell focused on lessons learned from prior years' activities and 
presented mitigation measures for avoiding potential conflicts, which 
are outlined in the 2012 POC and this document. For the 2012 Camden Bay 
drilling program, Shell's POC with Chukchi Sea villages primarily 
addresses the issue of transit of vessels, whereas the POC with 
Beaufort Sea villages addresses vessel transit, drilling, and 
associated activities. Communities that were consulted regarding 
Shell's 2012 Arctic Ocean operations include: Barrow, Kaktovik, 
Wainwright, Kotzebue, Kivalina, Point Lay, Point Hope, Kiana, Gambell, 
Savoonga, and Shishmaref.
    Beginning in early January 2009 and continuing into 2011, Shell 
held one-on-one meetings with representatives from the North Slope 
Borough (NSB) and Northwest Arctic Borough (NWAB), subsistence-user 
group leadership, and Village Whaling Captain Association 
representatives. Shell's primary purpose in holding individual meetings 
was to inform and prepare key leaders, prior to the public meetings, so 
that they would be prepared to give appropriate feedback on planned 
activities.
    Shell presented the proposed project to the NWAB Assembly on 
January 27, 2009, to the NSB Assembly on February 2, 2009, and to the 
NSB and NWAB Planning Commissions in a joint meeting on March 25, 2009. 
Meetings were also scheduled with representatives from the Alaska 
Eskimo Whaling Commission (AEWC), and presentations on proposed 
activities were given to the Inupiat Community of the Arctic Slope, and 
the Native Village of Barrow. On December 8, 2009, Shell held 
consultation meetings with

[[Page 69023]]

representatives from the various marine mammal commissions. Prior to 
drilling in 2012, Shell will also hold additional consultation meetings 
with the affected communities and subsistence user groups, NSB, and 
NWAB to discuss the mitigation measures included in the POC. Shell also 
attended the 2011 Conflict Avoidance Agreement (CAA) negotiation 
meetings in support of a limited program of marine environmental 
baseline activities in 2011 taking place in the Beaufort and Chukchi 
seas. Shell has stated that it is committed to a CAA process and will 
demonstrate this by making a good-faith effort to negotiate a CAA every 
year it has planned activities.
    The following mitigation measures, plans and programs, are integral 
to the POC and were developed during consultation with potentially 
affected subsistence groups and communities. These measures, plans, and 
programs will be implemented by Shell during its 2012 exploration 
drilling operations in both the Beaufort and Chukchi Seas to monitor 
and mitigate potential impacts to subsistence users and resources. The 
mitigation measures Shell has adopted and will implement during its 
2012 Camden Bay exploration drilling operations are listed and 
discussed below. The most recent version of Shell's planned mitigation 
measures was presented to community leaders and subsistence user groups 
starting in January of 2009 and has evolved since in response to 
information learned during the consultation process.
    To minimize any cultural or resource impacts to subsistence whaling 
activities from its exploration operations, Shell will suspend drilling 
activities on August 25, 2012, prior to the start of the Kaktovik and 
Cross Island bowhead whale hunting season. The drillship and associated 
vessels will remain outside of the Camden Bay area during the hunt. 
Shell will resume drilling operations after the conclusion of the hunt 
and, depending on ice and weather conditions, continue its exploration 
activities through October 31, 2012. In addition to the adoption of 
this project timing restriction, Shell will implement the following 
additional measures to ensure coordination of its activities with local 
subsistence users to minimize further the risk of impacting marine 
mammals and interfering with the subsistence hunts for marine mammals:
    (1) The drillship and support vessels will transit through the 
Chukchi Sea along a route that lies offshore of the polynya zone. In 
the event the transit outside of the polynya zone results in Shell 
having to break ice (as opposed to managing ice by pushing it out of 
the way), the drillship and support vessels will enter into the polynya 
zone far enough so that ice breaking is not necessary. If it is 
necessary to move into the polynya zone, Shell will notify the local 
communities of the change in the transit route through the Com Centers;
    (2) Shell has developed a Communication Plan and will implement the 
plan before initiating exploration drilling operations to coordinate 
activities with local subsistence users as well as Village Whaling 
Associations in order to minimize the risk of interfering with 
subsistence hunting activities and keep current as to the timing and 
status of the bowhead whale migration, as well as the timing and status 
of other subsistence hunts. The Communication Plan includes procedures 
for coordination with Com and Call Centers to be located in coastal 
villages along the Chukchi and Beaufort Seas during Shell's proposed 
activities in 2012;
    (3) Shell will employ local Subsistence Advisors from the Beaufort 
and Chukchi Sea villages to provide consultation and guidance regarding 
the whale migration and subsistence hunt. There will be a total of nine 
subsistence advisor-liaison positions (one per village), to work 
approximately 8-hours per day and 40-hour weeks through Shell's 2012 
exploration project. The subsistence advisor will use local knowledge 
(Traditional Knowledge) to gather data on subsistence lifestyle within 
the community and advise on ways to minimize and mitigate potential 
impacts to subsistence resources during the drilling season. 
Responsibilities include reporting any subsistence concerns or 
conflicts; coordinating with subsistence users; reporting subsistence-
related comments, concerns, and information; and advising how to avoid 
subsistence conflicts. A subsistence advisor handbook will be developed 
prior to the operational season to specify position work tasks in more 
detail;
    (4) Shell will implement flight restrictions prohibiting aircraft 
from flying within 1,000 ft (305 m) of marine mammals or below 1,500 ft 
(457 m) altitude (except during takeoffs and landings or in emergency 
situations) while over land or sea;
    (5) The drilling support fleet will avoid known fragile ecosystems, 
including the Ledyard Bay Critical Habitat Unit and will include 
coordination through the Com Centers;
    (6) All vessels will maintain cruising speed not to exceed 9 knots 
while transiting the Beaufort Sea;
    (7) Collect all drilling mud and cuttings with adhered mud from all 
well sections below the 26-inch (20-inch casing) section, as well as 
treated sanitary waste water, domestic wastes, bilge water, and ballast 
water and transport them outside the Arctic for proper disposal in an 
Environmental Protection Agency licensed treatment/disposal site. These 
waste streams shall not be discharged into the ocean;
    (8) Drilling mud shall be cooled to mitigate any potential 
permafrost thawing or thermal dissociation of any methane hydrates 
encountered during exploration drilling if such materials are present 
at the drill site; and
    (9) Drilling mud shall be recycled to the extent practicable based 
on operational considerations (e.g., whether mud properties have 
deteriorated to the point where they cannot be used further) so that 
the volume of the mud disposed of at the end of the drilling season is 
reduced.
    The POC also contains measures regarding ice management procedures, 
critical operations procedures, the blowout prevention program, and oil 
spill response. Some of the oil spill response measures to reduce 
impacts to subsistence hunts include: Having the primary OSRV on 
standby at all times so that it is available within 1 hour if needed; 
the remainder of the OSR fleet will be available within 72 hours if 
needed and will be capable of collecting oil on the water up to the 
calculated Worst Case Discharge; oil spill containment equipment will 
be available in the unlikely event of a blowout; capping stack 
equipment will be stored aboard one of the ice management vessels and 
will be available for immediate deployment in the unlikely event of a 
blowout; and pre-booming will be required for all fuel transfers 
between vessels.

Unmitigable Adverse Impact Analysis

    Shell has adopted a spatial and temporal strategy for its Camden 
Bay operations that should minimize impacts to subsistence hunters. 
First, Shell's activities will not commence until after the spring 
hunts have occurred. Additionally, Shell will traverse the Chukchi Sea 
far offshore, so as to not interfere with July hunts in the Chukchi Sea 
and will communicate with the Com Centers to notify local communities 
of any changes in the transit route. Once Shell is on location in 
Camden Bay, Beaufort Sea, whaling will not commence until late August/
early September. Shell has agreed to cease operations on August 25 to 
allow the villages of Kaktovik and Nuiqsut to prepare for the fall 
bowhead hunts, will

[[Page 69024]]

move the drillship and all support vessels out of the hunting area so 
that there are no physical barriers between the marine mammals and the 
hunters, and will not recommence activities until the close of both 
villages' hunts.
    Kaktovik is located 60 mi (96.6 km) east of the project area. 
Therefore, westward migrating whales would reach Kaktovik before 
reaching the area of Shell's activities or any of the ensonified zones. 
Although Cross Island and Barrow are west of Shell's drill sites, sound 
generating activities from Shell's drilling program will have ceased 
prior to the whales passing through the area. Additionally, Barrow lies 
298 mi (479.6 km) west of Shell's Camden Bay drill sites, so whalers in 
that area would not be displaced by any of Shell's activities.
    Adverse impacts are not anticipated on sealing activities since the 
majority of hunts for seals occur in the winter and spring, when Shell 
will not be operating. Sealing activities in the Colville River delta 
area occur more than 100 mi (161 km) from Shell's Camden Bay drill 
sites.
    Shell will also support the village Com Centers in the Arctic 
communities and employ local SAs from the Beaufort and Chukchi Sea 
villages to provide consultation and guidance regarding the whale 
migration and subsistence hunt. The SAs will provide advice to Shell on 
ways to minimize and mitigate potential impacts to subsistence 
resources during the drilling season.
    In the unlikely event of a major oil spill in the Beaufort Sea, 
there could be major impacts on the availability of marine mammals for 
subsistence uses. As discussed earlier in this document, the 
probability of a major oil spill occurring over the life of the project 
is low (Bercha, 2008). Additionally, Shell developed an ODPCP, which is 
currently under review by the Department of the Interior and several 
Federal agencies and the public. Shell has also incorporated several 
mitigation measures into its operational design to reduce further the 
risk of an oil spill. Copies of Shell's 2012 Camden Bay Exploration 
Plan and ODPCP can be found on the Internet at: http://www.alaska.boemre.gov/ref/ProjectHistory/2012Shell_BF/revisedEP/EP.pdf 
and http://www.alaska.boemre.gov/fo/ODPCPs/2010_BF_rev1.pdf, 
respectively.

Proposed Incidental Harassment Authorization

    This section contains a draft of the IHA itself. The wording 
contained in this section is proposed for inclusion in the IHA (if 
issued).
    (1) This Authorization is valid from July 10, 2012, through October 
31, 2012.
    (2) This Authorization is valid only for activities associated with 
Shell's 2012 Camden Bay exploration drilling program. The specific 
areas where Shell's exploration drilling program will be conducted are 
within Shell lease holdings in the Outer Continental Shelf Lease Sale 
195 and 202 areas in the Beaufort Sea.
    (3)(a) The incidental taking of marine mammals, by Level B 
harassment only, is limited to the following species: Bowhead whale; 
gray whale; beluga whale; harbor porpoise; ringed seal; bearded seal; 
spotted seal; and ribbon seal.
    (3)(b) The taking by injury (Level A harassment), serious injury, 
or death of any of the species listed in Condition 3(a) or the taking 
of any kind of any other species of marine mammal is prohibited and may 
result in the modification, suspension or revocation of this 
Authorization.
    (4) The authorization for taking by harassment is limited to the 
following acoustic sources (or sources with comparable frequency and 
intensity) and from the following activities:
    (a) 8-airgun array with a total discharge volume of 760 in\3\;
    (b) continuous drillship sounds during active drilling operations; 
and
    (c) vessel sounds generated during active ice management or 
icebreaking.
    (5) The taking of any marine mammal in a manner prohibited under 
this Authorization must be reported immediately to the Chief, Permits 
and Conservation Division, Office of Protected Resources, NMFS or his 
designee.
    (6) The holder of this Authorization must notify the Chief of the 
Permits and Conservation Division, Office of Protected Resources, at 
least 48 hours prior to the start of exploration drilling activities 
(unless constrained by the date of issuance of this Authorization in 
which case notification shall be made as soon as possible).
    (7) General Mitigation and Monitoring Requirements: The Holder of 
this Authorization is required to implement the following mitigation 
and monitoring requirements when conducting the specified activities to 
achieve the least practicable impact on affected marine mammal species 
or stocks:
    (a) All vessels shall reduce speed to at least 9 knots when within 
300 yards (274 m) of whales. The reduction in speed will vary based on 
the situation but must be sufficient to avoid interfering with the 
whales. Those vessels capable of steering around such groups should do 
so. Vessels may not be operated in such a way as to separate members of 
a group of whales from other members of the group;
    (b) Avoid multiple changes in direction and speed when within 300 
yards (274 m) of whales;
    (c) When weather conditions require, such as when visibility drops, 
support vessels must reduce speed and change direction, as necessary 
(and as operationally practicable), to avoid the likelihood of injury 
to whales;
    (d) All vessels shall maintain cruising speed not to exceed 9 knots 
while transiting the Beaufort Sea in order to reduce the risk of ship-
whale collisions;
    (e) Aircraft shall not fly within 1,000 ft (305 m) of marine 
mammals or below 1,500 ft (457 m) altitude (except during takeoffs, 
landings, or in emergency situations) while over land or sea;
    (f) Utilize two, NMFS-qualified, vessel-based Protected Species 
Observers (PSOs) (except during meal times and restroom breaks, when at 
least one PSO shall be on watch) to visually watch for and monitor 
marine mammals near the drillship or support vessel during active 
drilling or airgun operations (from nautical twilight-dawn to nautical 
twilight-dusk) and before and during start-ups of airguns day or night. 
The vessels' crew shall also assist in detecting marine mammals, when 
practicable. PSOs shall have access to reticle binoculars (7x50 
Fujinon), big-eye binoculars (25x150), and night vision devices. PSO 
shifts shall last no longer than 4 hours at a time and shall not be on 
watch more than 12 hours in a 24-hour period. PSOs shall also make 
observations during daytime periods when active operations are not 
being conducted for comparison of animal abundance and behavior, when 
feasible;
    (g) When a mammal sighting is made, the following information about 
the sighting will be recorded:
    (i) Species, group size, age/size/sex categories (if determinable), 
behavior when first sighted and after initial sighting, heading (if 
consistent), bearing and distance from the MMO, apparent reaction to 
activities (e.g., none, avoidance, approach, paralleling, etc.), 
closest point of approach, and behavioral pace;
    (ii) Time, location, speed, activity of the vessel, sea state, ice 
cover, visibility, and sun glare; and
    (iii) The positions of other vessel(s) in the vicinity of the MMO 
location.
    (iv) The ship's position, speed of support vessels, and water 
temperature, water depth, sea state, ice cover, visibility, and sun 
glare will also be recorded at the start and end of each observation 
watch, every 30 minutes

[[Page 69025]]

during a watch, and whenever there is a change in any of those 
variables.
    (h) PSO teams shall consist of Inupiat observers and experienced 
field biologists. An experienced field crew leader will supervise the 
PSO team onboard the survey vessel. New observers shall be paired with 
experienced observers to avoid situations where lack of experience 
impairs the quality of observations;
    (i) PSOs will complete a two- or three-day training session on 
marine mammal monitoring, to be conducted shortly before the 
anticipated start of the 2012 open-water season. The training 
session(s) will be conducted by qualified marine mammalogists with 
extensive crew-leader experience during previous vessel-based 
monitoring programs. A marine mammal observers' handbook, adapted for 
the specifics of the planned program will be reviewed as part of the 
training;
    (j) If there are Alaska Native PSOs, the PSO training that is 
conducted prior to the start of the survey activities shall be 
conducted with both Alaska Native PSOs and biologist PSOs being trained 
at the same time in the same room. There shall not be separate training 
courses for the different PSOs; and
    (k) PSOs shall be trained using visual aids (e.g., videos, photos), 
to help them identify the species that they are likely to encounter in 
the conditions under which the animals will likely be seen.
    (8) ZVSP Mitigation and Monitoring Measures: The Holder of this 
Authorization is required to implement the following mitigation and 
monitoring requirements when conducting the specified activities to 
achieve the least practicable impact on affected marine mammal species 
or stocks:
    (a) PSOs shall conduct monitoring while the airgun array is being 
deployed or recovered from the water;
    (b) PSOs shall visually observe the entire extent of the exclusion 
zone (EZ) (180 dB re 1 [mu]Pa [rms] for cetaceans and 190 dB re 1 
[mu]Pa [rms] for pinnipeds) using NMFS-qualified PSOs, for at least 30 
minutes (min) prior to starting the airgun array (day or night). If the 
PSO finds a marine mammal within the EZ, Shell must delay the seismic 
survey until the marine mammal(s) has left the area. If the PSO sees a 
marine mammal that surfaces then dives below the surface, the PSO shall 
continue the watch for 30 min. If the PSO sees no marine mammals during 
that time, they should assume that the animal has moved beyond the EZ. 
If for any reason the entire radius cannot be seen for the entire 30 
min period (i.e., rough seas, fog, darkness), or if marine mammals are 
near, approaching, or in the EZ, the airguns may not be ramped-up. If 
one airgun is already running at a source level of at least 180 dB re 1 
[mu]Pa (rms), the Holder of this Authorization may start the second 
airgun without observing the entire EZ for 30 min prior, provided no 
marine mammals are known to be near the EZ;
    (c) Establish and monitor a 180 dB re 1 [mu]Pa (rms) and a 190 dB 
re 1 [mu]Pa (rms) EZ for marine mammals before the 8-airgun array (760 
in\3\) is in operation; and a 180 dB re 1 [mu]Pa (rms) and a 190 dB re 
1 [mu]Pa (rms) EZ before a single airgun (40 in\3\) is in operation, 
respectively. For purposes of the field verification tests, described 
in condition 10(c)(i) below, the 180 dB radius is predicted to be 0.77 
mi (1.24 km) and the 190 dB radius is predicted to be 0.33 mi (524 m);
    (d) Implement a ``ramp-up'' procedure when starting up at the 
beginning of seismic operations, which means start the smallest gun 
first and add airguns in a sequence such that the source level of the 
array shall increase in steps not exceeding approximately 6 dB per 5-
min period. During ramp-up, the PSOs shall monitor the EZ, and if 
marine mammals are sighted, a power-down, or shut-down shall be 
implemented as though the full array were operational. Therefore, 
initiation of ramp-up procedures from shut-down requires that the PSOs 
be able to view the full EZ;
    (e) Power-down or shutdown the airgun(s) if a marine mammal is 
detected within, approaches, or enters the relevant EZ. A shutdown 
means all operating airguns are shutdown (i.e., turned off). A power-
down means reducing the number of operating airguns to a single 
operating 40 in\3\ airgun, which reduces the EZ to the degree that the 
animal(s) is no longer in or about to enter it;
    (f) Following a power-down, if the marine mammal approaches the 
smaller designated EZ, the airguns must then be completely shutdown. 
Airgun activity shall not resume until the PSO has visually observed 
the marine mammal(s) exiting the EZ and is not likely to return, or has 
not been seen within the EZ for 15 min for species with shorter dive 
durations (small odontocetes and pinnipeds) or 30 min for species with 
longer dive durations (mysticetes);
    (g) Following a power-down or shut-down and subsequent animal 
departure, airgun operations may resume following ramp-up procedures 
described in Condition 8(d) above;
    (h) ZVSP surveys may continue into night and low-light hours if 
such segment(s) of the survey is initiated when the entire relevant EZs 
are visible and can be effectively monitored; and
    (i) No initiation of airgun array operations is permitted from a 
shutdown position at night or during low-light hours (such as in dense 
fog or heavy rain) when the entire relevant EZ cannot be effectively 
monitored by the PSO(s) on duty.
    (9) Subsistence Mitigation Measures: To ensure no unmitigable 
adverse impact on subsistence uses of marine mammals, the Holder of 
this Authorization shall:
    (a) Traverse north through the Bering Strait through the Chukchi 
Sea along a route that lies offshore of the polynya zone. In the event 
the transit outside of the polynya zone results in Shell having to 
break ice, the drilling vessel and support vessels will enter into the 
polynya zone far enough so that icebreaking is not necessary. If it is 
necessary to move into the polynya zone, Shell shall notify the local 
communities of the change in transit route through the Communication 
and Call Centers (Com Centers). As soon as the fleet transits past the 
ice, it will exit the polynya zone and continue a path in the open sea 
toward the Camden Bay drill sites;
    (b) Implement the Communication Plan before initiating exploration 
drilling operations to coordinate activities with local subsistence 
users and Village Whaling Associations in order to minimize the risk of 
interfering with subsistence hunting activities;
    (c) Participate in the Com Center Program. The Com Centers shall 
operate 24 hours/day during the 2012 bowhead whale hunt;
    (d) Employ local Subsistence Advisors (SAs) from the Beaufort and 
Chukchi Sea villages to provide consultation and guidance regarding the 
whale migration and subsistence hunt;
    (e) Not operate aircraft below 1,500 ft (457 m) unless engaged in 
marine mammal monitoring, approaching, landing or taking off, or unless 
engaged in providing assistance to a whaler or in poor weather (low 
ceilings) or any other emergency situations;
    (f) Collect all drilling mud and cuttings with adhered mud from all 
well sections below the 26-inch (20-inch casing) section, as well as 
treated sanitary waste water, domestic wastes, bilge water, and ballast 
water and transport them outside the Arctic for proper disposal in an 
Environmental Protection Agency licensed treatment/disposal site. These 
waste streams shall not be discharged into the ocean;
    (g) Cool all drilling mud to mitigate any potential permafrost 
thawing or thermal dissociation of any methane

[[Page 69026]]

hydrates encountered during exploration drilling if such materials are 
present at the drill site;
    (h) Recycle all drilling mud to the extent practicable based on 
operational considerations (e.g., whether mud properties have 
deteriorated to the point where they cannot be used further) so that 
the volume of the mud disposed of at the end of the drilling season is 
reduced; and
    (i) Suspended all drilling activities on August 25 for the Kaktovik 
and Nuiqsut (Cross Island) fall bowhead whale hunts. The drilling 
vessel and support fleet shall leave the Camden Bay project area and 
move to an area north of latitude 71[deg]25' N and west of longitude 
146[deg]4' W. Shell shall not return to the area to resume drilling 
operations until the close of the Kaktovik and Nuiqsut fall bowhead 
whale hunts.
(10) Monitoring Measures
    (a) Vessel-based Monitoring: The Holder of this Authorization shall 
designate biologically-trained PSOs to be aboard the drillship and all 
support vessels. The PSOs are required to monitor for marine mammals in 
order to implement the mitigation measures described in conditions 7 
and 8 above;
    (b) Aerial Survey Monitoring: The Holder of this Authorization must 
implement the aerial survey monitoring program detailed in its Marine 
Mammal Mitigation and Monitoring Plan (4MP). The surveys must commence 
5 to 7 days before operations at the exploration well sites get 
underway. Surveys shall be flown daily throughout operations, weather 
and flight conditions permitting and shall continue for 5 to 7 days 
after all activities at the site have ended; and
    (c) Acoustic Monitoring:
    (i) Field Source Verification: the Holder of this Authorization is 
required to conduct sound source verification tests for the drilling 
vessel, support vessels, and the airgun array. Sound source 
verification shall consist of distances where broadside and endfire 
directions at which broadband received levels reach 190, 180, 170, 160, 
and 120 dB re 1 [mu]Pa (rms) for all active acoustic sources that may 
be used during the activities. For the airgun array, the configurations 
shall include at least the full array and the operation of a single 
source that will be used during power downs. The test results shall be 
reported to NMFS within 5 days of completing the test.
    (ii) Acoustic Study of Bowhead Deflections: Deploy acoustic 
recorders at five sites along the bowhead whale migration path in order 
to record vocalizations of bowhead whales as they pass through the 
exploration drilling area. This program must be implemented as detailed 
in the 4MP.
    (11) Reporting Requirements: The Holder of this Authorization is 
required to:
    (a) Within 5 days of completing the sound source verification tests 
for the drillship, support vessels, and the airguns, the Holder shall 
submit a preliminary report of the results to NMFS. The report should 
report down to the 120-dB radius in 10-dB increments;
    (b) Submit a draft report on all activities and monitoring results 
to the Office of Protected Resources, NMFS, within 90 days of the 
completion of the exploration drilling program. This report must 
contain and summarize the following information:
    (i) Summaries of monitoring effort (e.g., total hours, total 
distances, and marine mammal distribution through the study period, 
accounting for sea state and other factors affecting visibility and 
detectability of marine mammals);
    (ii) analyses of the effects of various factors influencing 
detectability of marine mammals (e.g., sea state, number of observers, 
and fog/glare);
    (iii) species composition, occurrence, and distribution of marine 
mammal sightings, including date, water depth, numbers, age/size/gender 
categories (if determinable), group sizes, and ice cover;
    (iv) sighting rates of marine mammals during periods with and 
without exploration drilling activities (and other variables that could 
affect detectability), such as: (A) Initial sighting distances versus 
drilling state; (B) closest point of approach versus drilling state; 
(C) observed behaviors and types of movements versus drilling state; 
(D) numbers of sightings/individuals seen versus drilling state; (E) 
distribution around the survey vessel versus drilling state; and (F) 
estimates of take by harassment;
    (v) Reported results from all hypothesis tests should include 
estimates of the associated statistical power when practicable;
    (vi) Estimate and report uncertainty in all take estimates. 
Uncertainty could be expressed by the presentation of confidence 
limits, a minimum-maximum, posterior probability distribution, etc.; 
the exact approach would be selected based on the sampling method and 
data available;
    (vii) The report should clearly compare authorized takes to the 
level of actual estimated takes.
    (viii) If, after the independent monitoring plan peer review 
changes are made to the monitoring program, those changes must be 
detailed in the report.
    (c) The draft report will be subject to review and comment by NMFS. 
Any recommendations made by NMFS must be addressed in the final report 
prior to acceptance by NMFS. The draft report will be considered the 
final report for this activity under this Authorization if NMFS has not 
provided comments and recommendations within 90 days of receipt of the 
draft report.
    (d) A draft comprehensive report describing the aerial, acoustic, 
and vessel-based monitoring programs will be prepared and submitted 
within 240 days of the date of this Authorization. The comprehensive 
report will describe the methods, results, conclusions and limitations 
of each of the individual data sets in detail. The report will also 
integrate (to the extent possible) the studies into a broad based 
assessment of all industry activities and their impacts on marine 
mammals in the Arctic Ocean during 2012.
    (e) The draft comprehensive report will be subject to review and 
comment by NMFS, the AEWC, and the NSB Department of Wildlife 
Management. The draft comprehensive report will be accepted by NMFS as 
the final comprehensive report upon incorporation of comments and 
recommendations.
    (12)(a) In the unanticipated event that the drilling program 
operation clearly causes the take of a marine mammal in a manner 
prohibited by this Authorization, such as an injury (Level A 
harassment), serious injury or mortality (e.g., ship-strike, gear 
interaction, and/or entanglement), Shell shall immediately cease 
operations and immediately report the incident to the Chief of the 
Permits and Conservation Division, Office of Protected Resources, NMFS, 
by phone or email and the Alaska Regional Stranding Coordinators. The 
report must include the following information: (i) Time, date, and 
location (latitude/longitude) of the incident; (ii) the name and type 
of vessel involved; (iii) the vessel's speed during and leading up to 
the incident; (iv) description of the incident; (v) status of all sound 
source use in the 24 hours preceding the incident; (vi) water depth; 
(vii) environmental conditions (e.g., wind speed and direction, 
Beaufort sea state, cloud cover, and visibility); (viii) description of 
marine mammal observations in the 24 hours preceding the incident; (ix) 
species identification or description of the animal(s) involved; (x) 
the fate of the animal(s); (xi) and photographs or video footage of the 
animal (if equipment is available).

[[Page 69027]]

    Activities shall not resume until NMFS is able to review the 
circumstances of the prohibited take. NMFS shall work with Shell to 
determine what is necessary to minimize the likelihood of further 
prohibited take and ensure MMPA compliance. Shell may not resume their 
activities until notified by NMFS via letter, email, or telephone.
    (b) In the event that Shell discovers an injured or dead marine 
mammal, and the lead PSO determines that the cause of the injury or 
death is unknown and the death is relatively recent (i.e., in less than 
a moderate state of decomposition as described in the next paragraph), 
Shell will immediately report the incident to the Chief of the Permits 
and Conservation Division, Office of Protected Resources, NMFS, by 
phone or email and the NMFS Alaska Stranding Hotline and/or by email to 
the Alaska Regional Stranding Coordinators. The report must include the 
same information identified in Condition 12(a) above. Activities may 
continue while NMFS reviews the circumstances of the incident. NMFS 
will work with Shell to determine whether modifications in the 
activities are appropriate.
    (c) In the event that Shell discovers an injured or dead marine 
mammal, and the lead PSO determines that the injury or death is not 
associated with or related to the activities authorized in Condition 2 
of this Authorization (e.g., previously wounded animal, carcass with 
moderate to advanced decomposition, or scavenger damage), Shell shall 
report the incident to the Chief of the Permits and Conservation 
Division, Office of Protected Resources, NMFS, by phone or email and 
the NMFS Alaska Stranding Hotline and/or by email to the Alaska 
Regional Stranding Coordinators, within 24 hours of the discovery. 
Shell shall provide photographs or video footage (if available) or 
other documentation of the stranded animal sighting to NMFS and the 
Marine Mammal Stranding Network. Activities may continue while NMFS 
reviews the circumstances of the incident.
    (13) Activities related to the monitoring described in this 
Authorization do not require a separate scientific research permit 
issued under section 104 of the Marine Mammal Protection Act.
    (14) The Plan of Cooperation outlining the steps that will be taken 
to cooperate and communicate with the native communities to ensure the 
availability of marine mammals for subsistence uses must be 
implemented.
    (15) Shell is required to comply with the Terms and Conditions of 
the Incidental Take Statement (ITS) corresponding to NMFS's Biological 
Opinion issued to NMFS's Office of Protected Resources.
    (16) A copy of this Authorization and the ITS must be in the 
possession of all contractors and PSOs operating under the authority of 
this Incidental Harassment Authorization.
    (17) Penalties and Permit Sanctions: Any person who violates any 
provision of this Incidental Harassment Authorization is subject to 
civil and criminal penalties, permit sanctions, and forfeiture as 
authorized under the MMPA.
    (18) This Authorization may be modified, suspended or withdrawn if 
the Holder fails to abide by the conditions prescribed herein or if the 
authorized taking is having more than a negligible impact on the 
species or stock of affected marine mammals, or if there is an 
unmitigable adverse impact on the availability of such species or 
stocks for subsistence uses.

Endangered Species Act (ESA)

    There is one marine mammal species listed as endangered under the 
ESA with confirmed or possible occurrence in the proposed project area: 
the bowhead whale. NMFS' Permits and Conservation Division will 
initiate consultation with NMFS' Endangered Species Division under 
section 7 of the ESA on the issuance of an IHA to Shell under section 
101(a)(5)(D) of the MMPA for this activity. Consultation will be 
concluded prior to a determination on the issuance of an IHA.

National Environmental Policy Act (NEPA)

    NMFS is currently preparing an Environmental Assessment (EA), 
pursuant to NEPA, to determine whether the issuance of an IHA to Shell 
for its 2012 drilling activities may have a significant impact on the 
human environment. NMFS expects to release a draft of the EA for public 
comment, and will inform the public, through the Federal Register and 
posting on our Web site, once a draft is available (see ADDRESSES).

Request for Public Comment

    As noted above, NMFS requests comment on our analysis, the draft 
authorization, and any other aspect of the Notice of Proposed IHA for 
Shell's 2012 Beaufort Sea exploratory drilling program. Please include, 
with your comments, any supporting data or literature citations to help 
inform our final decision on Shell's request for an MMPA authorization.

    Dated: October 31, 2011.
James H. Lecky,
Director, Office of Protected Resources, National Marine Fisheries 
Service.
[FR Doc. 2011-28641 Filed 11-4-11; 8:45 am]
BILLING CODE 3510-22-P