[Federal Register Volume 78, Number 36 (Friday, February 22, 2013)]
[Notices]
[Pages 12542-12584]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2013-03681]



[[Page 12541]]

Vol. 78

Friday,

No. 36

February 22, 2013

Part IV





Department of Commerce





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National Oceanic and Atmospheric Administration





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

  Federal Register / Vol. 78, No. 36 / Friday, February 22, 2013 / 
Notices  

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DEPARTMENT OF COMMERCE

National Oceanic and Atmospheric Administration

RIN 0648-XC494


Takes of Marine Mammals Incidental to Specified Activities; 
Taking Marine Mammals Incidental to an Exploration Drilling Program in 
the Chukchi 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 ConocoPhillips Company (COP) 
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 Chukchi Sea, Alaska. 
Pursuant to the Marine Mammal Protection Act (MMPA), NMFS is requesting 
comments on its proposal to issue an IHA to COP to take, by Level B 
harassment only, 12 species of marine mammals during the specified 
activity.

DATES: Comments and information must be received no later than March 
25, 2013.

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 25-
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 COP'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 March 1, 2012, from COP for the 
taking, by harassment, of marine mammals incidental to offshore 
exploration drilling on OCS leases in the Chukchi Sea, Alaska. However, 
before NMFS had an opportunity to review and comment on the March 1, 
2012, submission, COP notified NMFS that they were making changes to 
the request and submitted a new application on July 16, 2012. NMFS 
reviewed COP's application and identified a number of issues requiring 
further clarification. After addressing comments from NMFS, COP 
modified its application and submitted a final revised application on 
December 6, 2012. NMFS carefully evaluated COP's application, including 
their analyses, and determined that the application was complete. The 
December 6, 2012, submission (2nd application revision) is the one 
available for public comment (see ADDRESSES) and considered by NMFS for 
this proposed IHA.
    COP plans to drill up to two exploration wells on OCS leases 
offshore in the Chukchi Sea, Alaska, at the Devils Paw prospect during 
the 2014 Arctic open-water season (July through October). Impacts to 
marine mammals may occur from noise produced by the drill rig and 
support vessels alongside the drill rig in dynamic positioning (DP) 
mode, vertical seismic profile (VSP) surveys, and supporting vessels 
(including icebreakers) and aircraft. COP has requested an 
authorization to take 12 marine mammal species by Level B harassment, 
and NMFS is proposing to authorize take incidental to COP's offshore 
exploration drilling in the Chukchi Sea of the following species: 
beluga whale (Delphinapterus leucas); bowhead whale (Balaena 
mysticetus); gray whale (Eschrichtius robustus); killer whale (Orcinus 
orca); minke whale (Balaenoptera acutorostrata); fin whale 
(Balaenoptera physalus); humpback whale (Megaptera novaeangliae); 
harbor porpoise (Phocoena phocoena); bearded seal (Erignathus 
barbatus); ringed seal (Phoca hispida); spotted seal (P. largha); and 
ribbon seal (Histriophoca fasciata).

Description of the Specified Activity and Specified Geographic Region

    COP plans to conduct an offshore exploration drilling program on 
U.S.

[[Page 12543]]

Department of the Interior (DOI), Bureau of Ocean Energy Management 
(BOEM) Alaska OCS leases located greater than 70 mi (113 km) from the 
Chukchi Sea coast during the 2014 open-water season. During the 2014 
drilling program, COP plans to drill up to two exploration wells at the 
prospect known as Devils Paw. See Figure 1 in COP's application for the 
lease block and drill site locations (see ADDRESSES). The purpose of 
COP's program is to test whether oil deposits are present in a 
commercially viable quantity and quality. COP has stated that only if a 
significant accumulation of hydrocarbons is discovered will the company 
consider proceeding with development and production of the field.

Exploration Drilling

    All of the possible Chukchi Sea offshore drill sites are located 
approximately 120 mi (193 km) west of Wainwright, the community 
proposed to be used for permanent infrastructure support for the 
project. Approximate distances from the exploration drilling project 
area to other communities along the Chukchi coast are 200 mi (322 km) 
from Barrow, 90 mi (145 km) from Point Lay, and 175 mi (282 km) from 
Point Hope. Water depths at the potential drill sites range from 132-
138 ft (40.2-42 m). Table 2 in COP's application provides the 
coordinates for the potential drill sites (see ADDRESSES).
(1) Drill Rig Mobilization and Positioning
    COP proposes to use a jack-up rig, instead of a drillship, to 
conduct the proposed program. Generally, jack-up rigs consist of a 
buoyant steel hull with three or more legs on which the hull can be 
``jacked'' up or down. The jack-up drill rig has no self-propulsion 
capability and therefore needs to be transported by a heavy-lift vessel 
(HLV) from its original location to an area in the Bering Sea where it 
would then be placed in a floating mode under the control of three 
towing vessels. After delivering the jack-up rig, the HLV would depart 
immediately via the Bering Strait and would not return until completion 
of the project. When weather and ice conditions at the Devils Paw 
Prospect are favorable, the support vessels will tow the rig into 
position over the DP-5 drill site and initiate offloading.
    Offloading procedures are estimated to take from 24 to 36 hrs, 
dependent on weather. Initial drill rig placement and orientation would 
be determined by logistics, current and forecasted weather events, ice 
extent, ice type, underwriter requirements, and safety considerations. 
Actual positioning of the rig would be determined by the well design, 
geology, shallow hazards, and seabed conditions. The rig would then be 
jacked up, manned with a crew, and provisioned for commencing drilling. 
The horizontal dimensions of the rig will be approximately 230 x 225 ft 
(70 x 68 m). When operating, the hull will be about 40 ft (12 m) above 
seawater surface. Maximum dimension of one leg spud can, which is the 
part on the seafloor, is about 60 ft (18 m).
    If weather and ice conditions at the Devils Paw Prospect area are 
initially unfavorable, the HLV would transport the jack-up rig to the 
alternate staging area located about 20 mi (32 km) south of Kivalina 
and 6 mi (9.7 km) offshore (see Figure 1 in COP's application), offload 
the rig, and depart the Chukchi Sea via the Bering Strait. This 
alternative location has been chosen based on its proximity to 
infrastructure and likelihood to be ice free at the time of transfer. 
It may take up to 3 days to reach the prospect location from the 
alternate staging area (approximately 190 mi away [306 km]).
    If the rig is offloaded at the alternate staging area, it would be 
placed into standby mode, which means it would be temporarily jacked up 
and manned by a limited crew to wait for conditions to improve at the 
prospect. In addition, support helicopters would be mobilized to Red 
Dog Mine near Kotzebue as necessary. Once ice conditions and weather at 
the Devils Paw Prospect area turn favorable, the anchor handling supply 
tug (AHST) and other vessels standing by in the immediate vicinity of 
the rig would move the rig to the prospect area. The rig would then be 
jacked up, manned with a crew, and supplied to commence drilling. (2) 
Support Vessel and Aircraft Movements
    Various vessels will be involved in the drilling project, as 
summarized in Table 1 of COP's application (see ADDRESSES). The vessels 
involved in supporting the drilling operations will remain at about 5.5 
mi (9 km) distance from the drill rig when they are not actively 
supporting the drilling operations. Several vessels will also be 
available for oil spill response purposes (see Table 1 in COP's 
application). Most of these vessels are relatively small and will be 
located aboard a mother vessel, either the oil spill response barge or 
the landing craft. These vessels will not be deployed in the water, 
unless needed to respond to a spill or to conduct oil spill response 
exercises as directed by DOI's Bureau of Safety and Environmental 
Enforcement (BSEE). The oil spill response vessel (OSRV) will also be 
on standby at 5.5 mi (9 km) from the drill rig. In addition to the 
vessels required for the actual drilling operations, a science vessel 
will be conducting monitoring activities. Figure 3 in COP's application 
provides an overview of the approximate locations of the vessels 
relative to the rig. The vessels will be located upwind from the rig, 
and, as such, they could be moved to any quadrant (A, B, C, or D) 
denoted in the figure, depending on the prevailing wind and currents.
    COP also intends to have two helicopters and one fixed-wing 
airplane available as part of the operations. Helicopters would be used 
for personnel and equipment transport between shore and the drill rig 
consistently during operations. The airplane would be used for 
personnel and equipment transport between onshore locations. Wainwright 
would be the principal port from which crew transfers would take place; 
however, it is possible that under certain circumstances these 
activities might need to be conducted through Barrow or another 
location.
(3) Drill Rig Resupply
    Transport of supplies to and from the drill rig will primarily be 
done with the ware vessel and offshore supply vessels (OSVs), although 
any other project vessel with the capability of DP could be used. The 
supplies would be loaded in Wainwright onto the large landing craft 
from where they would be transferred to the supply vessels. This 
transfer of supplies will take place somewhere between 5.5 mi (9 km) of 
the drill rig and 5 mi (8 km) offshore of Wainwright. When not engaged 
in transfers of supplies, the ware vessel and OSVs will be located 
about 5.5 mi (9 km) from the drill rig. The large landing craft will be 
located somewhere between 5.5 mi (9 km) of the drill site and 5 mi (8 
km) offshore of Wainwright.
    The duration of each supply trip by the ware vessel and OSV is 
estimated to be up to 7 hrs, assuming the vessels depart from their 
standby location at about 5.5 mi (9 km) of the rig. It would take 
approximately 0.5 hr to travel one-way to the drill rig (cruising 
mode). The supply vessel would be dynamically positioned next to the 
rig for about 6 hrs for each transfer of fuel and less than 6 hrs for 
each transfer of other supplies. The transit time between the large 
landing craft and the supply vessels is about 3 hrs one-way.
    The ware vessel is estimated to make about two to three trips per 
week to the rig but could make an average of almost four resupply trips 
per week over 14 weeks. Based on an estimated 53 trips per season and a 
maximum of 6 hrs for

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supply transfer, the ware vessel would be in DP mode up to a total of 
318 hrs over the drilling season. The OSVs are estimated to make four 
and a half resupply trips per week over 14 weeks. Based on an estimated 
total of 63 trips, unloading supplies from the OSV to the rig would 
take up to a total of 378 hrs (in DP mode) over the course of the 
drilling season. Assuming that at any time only one supply vessel will 
be in DP alongside the drill rig, the total duration of DP is 696 hrs.
(4) Personnel Transfer and Refueling
    About 300 persons are estimated to be involved in the proposed 
exploration drilling overall. The jack-up drill rig, support and oil 
spill response vessels will be self-contained, and the crew will live 
aboard the rig and vessels. Air support will be necessary to meet 
personnel and supply needs once the rig is operational. The helicopter 
will fly a direct route between Wainwright and the drill rig, eight to 
ten times per week.
    Three refueling events per well are expected to be required for the 
drill rig, depending on the circumstances. The duration of a rig-
fueling event will be approximately 6 hrs. All refueling operations 
will follow procedures approved by the U.S. Coast Guard.

Vertical Seismic Profile Test

    COP intends to conduct two or three VSP data acquisition runs 
inside the wellbore to obtain high-resolution seismic images with 
detailed time-depth relationships and velocity profiles of the various 
geological layers. The VSP data can be used to help reprocess existing 
2D or 3D seismic data prior to drilling a potential future appraisal 
well in case oil or gas is discovered during the proposed exploration 
drilling.
    The procedure of one VSP data acquisition run can be summarized as 
follows (Figure 2 in COP's application provides a schematic of the 
layout):
     The source of energy for the VSP data acquisition, 
typically consisting of one or more airguns, will be lowered from the 
drilling platform or a vessel to a depth of approximately 10 ft (3 m) 
to 30 ft (10 m) below the water surface (depending on sea state). The 
total volume of the airgun(s) is not expected to exceed 760 in\3\.
     A minimum of two geophones positioned 50 ft (15.2 m) apart 
will be placed at the end of a wireline cable, which will be lowered 
into the wellbore to total depth. Once total depth has been reached, 
the wireline cable will be pulled up and stopped at predefined depths 
(geophone stations). Data will be acquired by producing a series of 
sound pulses from the airgun(s) over a period of approximately 1 min. 
The sound waves generated by the source and reflected from various 
geological layers will be recorded by the two geophones.
     After each 1-minute airgun activity, the wireline cable 
with the geophones will be pulled up to a shallower position in the 
well after which the airgun(s) will again produce a series of sound 
pulses over a period of approximately 1 min. This process will be 
repeated until data have been acquired at all pre-identified geophone 
stations.
    Two or three VSP data acquisition runs will be conducted; the first 
run will take place upon reaching the bottom of the 17.5-in (44.5 cm) 
borehole at approximately 5,220 ft (1,590 m) below sea level (bsl), the 
second run upon reaching the bottom of the 13.5 and 8.5 in (34.2 and 
21.5 cm) borehole at approximately 9,580 ft (2,920 m) bsl, and a 
possible third run upon reaching the bottom of the 6.5 in (16.5 cm) 
borehole at approximately 11,020 ft (33,590 m) bsl. If the integrity of 
the 8.5 in borehole allows drilling to 11,020 ft without the need for 
an extra casing a third VSP run might not be needed. The number of 
geophone stations for each of the three VSP data acquisition runs 
varies depending on the length of the wellbore to be surveyed. The time 
required to finish a VSP data acquisition run depends on the depth of 
the wellbore (resulting in longer time to lower and pull up the wire 
cable with geophones) and the number of stations (resulting in longer 
data acquisition time). The period between VSP data acquisition runs is 
about 7-10 days, depending on the drilling progress. The total amount 
of time that airguns are operating for the three runs combined that 
might be performed in a well is about 2 hrs, not including ramp up. In 
case a second well is drilled, two or three additional VSP data 
acquisition runs might be conducted, meaning an additional 2 hrs of 
airgun operations over the course of the entire open-water drilling 
season.

Ice Management

    Understanding ice systems and monitoring their movement are 
important aspects of COP's Chukchi Sea operations. COP has monitored 
Chukchi Sea ice since 2008 and would continue that monitoring through 
the proposed drilling season. Initial monitoring would incorporate 
satellite imagery to observe the early stages of sea ice retreat. Upon 
arrival in the project area, the ice management vessel, possibly with 
one other project vessel, would operate at the edge of the ice pack and 
monitor ice activity, updating all interested parties on ice pack 
coordinates to help determine scheduling for mobilization of the rig. 
COP has submitted an Ice Alerts Plan to BOEM for approval in connection 
with the Exploration Plan. The Ice Alerts Plan summarizes historic ice 
monitoring results which has assisted COP in estimating the timing and 
placement of the rig and support vessels. Under the COP Ice Alerts 
Plan, an ice monitoring and management center based out of Anchorage 
will monitor and interpret information collected from project vessels 
and satellite imagery during the entire drilling operation. A summary 
of the major components of COP's Ice Alerts Plan is provided below.
    The ice edge position will be tracked in near real time using 
observations from satellite images, from the ice management vessel or 
other project vessels. The ice management and project vessels used for 
ice observations will remain on standby within about 5.5 mi (9 km) of 
the drill rig, unless deployed to investigate migrating ice-floes. When 
investigating ice, the vessels will likely stay within about 75 mi (121 
km) of the rig. The Ice Alerts Plan includes a process for determining 
how close hazardous ice can approach before the well needs to be 
secured and the jack-up rig moved. This critical distance is a function 
of rig operations at that time, the speed and direction of the ice, the 
weather forecast, and the method of ice management.
    Based on available historical and more recent ice data, there is 
low probability of ice entering the drilling area during the open water 
season. However, if hazardous ice is on a trajectory to approach the 
rig, the ice management vessel will be available to respond. One option 
for responding is to use the vessels fire monitor (water cannon) to 
modify the trajectory of the floe. Another option is to redirect the 
ice by applying pressure with the bow of the ice management vessel, 
slowly pushing the ice away from the direction of the drill rig. At 
these slow speeds, the vessel would use low power and slow propeller 
rotation speed, thereby reducing noise generation from propeller 
rotation effects in the water. Icebreaking is not planned as a way to 
manage ice that may be on a trajectory toward the drilling rig. In case 
the jack-up rig needs to be moved due to approaching ice, the support 
vessels will tow the rig to a secure location.

Timeframe of Activities

    COP's anticipated start and end dates of the mobilization, drilling 
operations, and demobilization are on or about June 15, 2014, and 
November 16, 2014,

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respectively, with actual activities in the lease sale area taking 
place roughly from July through October. Vessels would not arrive at 
the prospect prior to July 1. The HLV with the jack-up drill rig is 
expected to originate from Southeast Asia or the North Sea. The HLV 
will depart the area as soon as it has offloaded the rig. The AHST, 
OSVs, and ware vessel will mobilize from the Gulf of Mexico in early 
June and will be traveling north in close proximity to the HLV and 
jack-up rig. The ice management vessel will be the first to mobilize to 
the drill site to provide information on ice conditions to the HLV and 
other vessels.
    COP anticipates the drilling of one well will take approximately 40 
days. After the first Devils Paw well is drilled, it will be plugged 
and abandoned. If there is enough time, as estimated by the ice 
monitoring system, COP intends to drill a second well, which could take 
another 40 days. Relocation of the rig from the first to the second 
well would take approximately 24-48 hrs. If a second well is drilled, 
it would also be plugged and abandoned.
    When drilling is completed, the jack-up rig will be demobilized and 
excess material transferred from the rig to supply vessels. The rig 
will then be jacked down and taken under tow by the AHST and OSVs to 
the load-out site, anticipated to be located south of the Devils Paw 
prospect area. The rig will remain in tow by the AHST until the HLV 
arrives. In case the drilling season ends earlier than anticipated, the 
rig may be towed to the alternate staging area and jacked up until the 
HLV arrives. In that situation, helicopters will be mobilized to Nome 
or the Red Dog Mine to support the rig as necessary. Once the AHST has 
the jack-up rig under tow, all other support vessels would be 
dismissed. The AHST and OSVs would accompany the rig until it is loaded 
onto the HLV. Once the rig has been loaded onto the HLV, the AHST, 
supply vessels, and air support will be demobilized.

Exploratory Drilling Program Sound Characteristics

    Potential impacts to marine mammals could occur from the noise 
produced by the jack-up rig and its support vessels (including the ice 
management vessels and during DP), aircraft, and the airgun array 
during VSP tests. The drill rig produces continuous noise into the 
marine environment. NMFS currently uses a threshold of 120 dB re 1 
[mu]Pa (rms) for the onset of Level B harassment from continuous sound 
sources. This 120 dB threshold is also applicable for the support 
vessels during DP. The airgun array proposed to be used by COP for the 
VSP tests produces pulsed noise into the marine environment. NMFS 
currently uses a threshold of 160 dB re 1 [mu]Pa (rms) for the onset of 
Level B harassment from pulsed sound sources.
(1) Drill Rig Sounds
    The main contributors to the underwater sound levels from jack-up 
rig drilling activities are the use of generators and drilling 
machinery. Few underwater noise measurements exist from operations 
using a drill rig. Here we summarize the results from the drilling rig 
Ocean General and its two support vessels in the Timor Sea, Northern 
Australia (McCauley, 1998) and the jack-up rig Spartan 151 in Cook 
Inlet, Alaska (MAI, 2011). For comparison, COP also included 
information on drilling sound measurements from a concrete drilling 
island and drillship. However, the sound propagation of a jack-up rig 
is substantially less than that of a drillship because the components 
that generate sound from a jack-up rig sit above the surface of the 
water instead of in the water.
    McCauley (1998) conducted measurements under three different 
conditions: (a) Drilling rig sounds without drilling; (b) actively 
drilling, with the support vessel on anchor; and (c) drilling with the 
support vessel loading the rig (McCauley, 1998). The primary noise 
sources from the drill rig itself were from mechanical plants, fluid 
discharges, pumping systems and miscellaneous banging of gear on the 
rig. The overall noise level was low (117 dB re 1[mu]Pa at 410 ft [125 
m]) mainly because the deck of the rig was well above the waterline 
(which is also the case for jack-up rigs). When the rig was actively 
drilling, the drill rig noise dominated the drilling sounds to a 
distance of about 1,312 ft (400 m). Beyond that distance, the energy 
from the drill string tones (in the 31 and 62 Hz \1/3\ octaves) became 
apparent and resulted in an increase in the overall received noise 
level. With the rig drilling, the highest noise levels encountered were 
on the order of 117 dB re 1[mu]Pa at 410 ft (125 m) and 115 dB 
re1[mu]Pa at 1,228 ft (405 m). The noise source that far exceeded the 
previous two was from the support vessel standing alongside the rig for 
loading purposes. The thrusters and main propellers were engaged to 
keep the vessel in position and produced high levels of cavitation 
sound. The sound was broadband in nature, with highest levels of 137 dB 
1[mu]Pa at 1,328 ft (405 m) and levels of 120 dB re 1[mu]Pa at 1.8-2.4 
mi (3-4 km) from the well head.
    Acoustic measurements of the drilling rig Spartan 151 were 
conducted to report on underwater sound characteristics as a function 
of range using two different systems (moored hydrophone and real time 
system). Both systems provided consistent results. Primary sources of 
rig-based underwater sounds were from the diesel engines, mud pump, 
ventilation fans (and associated exhaust), and electrical generators. 
The loudest source levels (from the diesel engines) were estimated at 
137 dB re 1 [mu]Pa at 1 m (rms) in the 141-178 Hz \1/3\ octave band. 
Based on this estimate, the 120 dB (rms) re 1 [mu]Pa sound pressure 
level would be at about 154 ft (50 m) away from where the energy enters 
the water (jack-up leg or drill riser).
    Hall and Francine (1991) measured drilling sounds from an offshore 
concrete island drilling structure. Source sound pressure level was 131 
dB re 1[mu]Pa at 1 m for the drilling structure at idle (no drilling), 
and a transmission loss rate of 2.6 dB per doubling of distance, 
slightly less than theoretical cylindrical spreading. At a distance of 
912 ft (278 m) from the drilling island the broadband sound pressure 
level was 109 dB re 1[mu]Pa. Strong tonal components at 1.375-1.5 Hz 
were detected in the acoustic records during drilling activities. These 
were likely associated with the rotary turntable, which was rotating 
between 75 and 110 rpm (which corresponds to 1.25-1.83 Hz). The 
received broadband sound pressure level at 849 ft (259 m) was 124 dB re 
1[mu]Pa. The sounds measured from the concrete drilling island were 
almost entirely (>95%) composed of energy below 20 Hz.
    Sound pressure levels of drilling activities from the concrete 
drilling island were substantially less than those reported for drill 
ships (Greene, 1987a). At a range of 557 ft (170 m) the 20-1000 Hz band 
level was 122-125 dB for the drillship Explorer I, with most energy 
below 600 Hz (although tones up to 1850 Hz were recorded). Drilling 
activity from the Explorer was measured as 134 dB at a range of 656 ft 
(200 m), with all energy below 600 Hz. Underwater sound measurements 
from the drillship Kulluk at 3,215 ft (980 m) were substantially higher 
(143 dB re 1[mu]Pa). Underwater sound levels recorded from the 
drillship Stena Forth in Disko Bay, Greenland, corresponded to 
measurements from other drillships and were higher than sound levels 
reported for semi-submersibles and drill rigs (Kyhn et al., 2011). The 
broadband source levels were similar to a fast

[[Page 12546]]

moving merchant vessel with source levels up to 184-190 dB re 1 [mu]Pa 
during drilling and maintenance work, respectively. At a range of 1,640 
ft (500 m) from the drillship the 10-1000 Hz band level during drilling 
at 295 ft (90 m) ranged from approximately 100-128 dB re1 [mu]Pa, with 
the highest sound level at 100 and 400 Hz. Sound levels were <=110 dB 
re1 [mu]Pa at 1.2 mi (2 km) distance.
    Expected sound pressure levels for the proposed drilling activities 
have been modeled by JASCO Applied Research, Inc. for drilling sounds 
only and for drilling sounds in combination with the proximity of a 
support vessel using DP. The acoustic modeling results show that the 
maximum radii to received sound levels of 120 and 160 dB re 1 [mu]Pa 
from drilling operations alone are 689 ft (210 m) and <33 ft (10 m), 
respectively (O'Neill et al., 2012). More detailed results are included 
in Attachment A of COP's IHA application.
(2) Vessel Sounds
    In addition to the drill rig, various types of vessels will be used 
in support of the operations including ice management vessels, anchor 
handlers, supply vessels and oil-spill response vessels. Like other 
industry-generated sound, underwater sound from vessels is generally 
most apparent at relatively low frequencies (20-500 Hz). The sound 
characteristic of each vessel is unique depending upon propulsion unit, 
machinery, hull size and shape. These characteristics change with load, 
vessel speed and weather conditions. For example, increase in vessel 
size, power and speed produces increasing broadband and tonal noise. 
The sound produced by vessels is generated by engine machinery and 
propeller cavitation. When a vessel increases speed, broadband sound 
from propeller cavitation and hull vibration becomes dominant over 
machinery sound. It has been estimated that propeller cavitation 
produces at least 90% of all ship generated ambient noise (Ross, 2005). 
Sound from large vessels is generally higher at low frequencies. Small 
high-powered (>100 horse power [HP]) propeller driven boats often 
exceed large vessel sound at frequencies above 1 kHz.
    Ice management vessels operating in thick ice require a greater 
amount of power and propeller cavitation and hence produce higher sound 
levels than ships of similar size during normal operation in open water 
(Richardson et al., 1995b). Roth and Schmidt (2010) examined ice 
management vessel sound pressure levels during different sea ice 
conditions and modes of propulsion. Comparison of source spectra in 
open-water and while breaking moderate ice showed increases as much as 
15 dB between 20 Hz and 2 kHz. For low frequencies, a sound pressure 
level of about 193 dB re 1[mu]Pa at 1 m was estimated to be a 
reasonable peak value.
    Numerous measurements of underwater vessel sound have been 
performed since 2000 (for review see Wyatt, 2008) mostly in support of 
industry activity. Results of underwater vessel sounds that have been 
measured in the Chukchi and Beaufort Seas were reported in various 90-
day and comprehensive reports since 2007 (e.g., Aerts et al., 2008; 
Hauser et al., 2008; Brueggeman et al., 2009a; Ireland et al., 2009). 
Due to the highly variable conditions under which these measurements 
were conducted, including equipment and methodology used, it is 
difficult to compare source levels (i.e., back calculated sound levels 
at a theoretical 1 m from the source) or even received levels between 
vessels. For example, source sound pressure levels of the same tug with 
barge varied from 173 dB to 182 dB re 1[mu]Pa at 1 m, depending on the 
speed and load at the time of measurement (Zykov and Hannay, 2006). 
Sound pressure levels of a drill rig support vessel traveling at a 
speed of about 11 knots (20 kph) was measured to be 136 dB re 1[mu]Pa 
at 1,312 ft (400 m) (McCauley, 1998). Acoustic measurements of an 
anchor handling support tug of similar size and horsepower traveling at 
4.3 knots (8 kph) resulted in sound pressure levels of approximately 
137 dB re 1[mu]Pa at 1,312 ft (400 m) and 120 dB re 1[mu]Pa at 4,855 ft 
(1,480 m) (Funk et al., 2008).
(3) Aircraft Sounds
    Helicopters are proposed to be used for personnel and equipment 
transport to and from the drill rig. Over calm water away from shore, 
the maximum transmission of rotor and engine sounds from helicopters 
into the water can generally be visualized as a 26[deg] cone under the 
aircraft. The size of the water surface area where transmission of 
sound can take place is therefore generally larger with a higher flight 
altitude, though the sound levels will be much lower due to the larger 
distance from the water. In practice, the width of the area where 
aircraft sounds will be received is usually wider than the 26[deg] cone 
and varies with sea state because waves provide suitable angles for 
additional transmission of the sound. In shallow water, scattering and 
absorption will limit lateral propagation. 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.
    Underwater sounds were measured for a Bell 212 helicopter (Greene 
1982, 1985; Richardson et al., 1990). These measurements show that 
there are numerous prominent tones at frequencies up to about 350 Hz, 
with the strongest measured tone at 20-22 Hz. Received peak sound 
levels of a Bell 212 passing over a hydrophone at an altitude of 
approximately 1,000 ft (300 m), varied between 106-111 dB re 1[mu]Pa at 
29 and 59 ft (9 and 18 m) water depth. Two Class 1 or Group A type 
helicopters will fly to and from the jack-up rig for transportation of 
manpower and supplies. Helicopters will be operated by a flight crew of 
two and capable of carrying 12 to 13 passengers.
(4) Vertical Seismic Profile Airgun Sounds
    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. 
Most energy emitted from airguns is at relatively low frequencies. 
Typical high-energy airgun arrays emit most energy at 10-120 Hz. 
However, the pulses contain significant energy up to 500-1000 Hz and 
some energy at higher frequencies (Goold and Fish, 1998; Potter et al., 
2007). Studies in the Gulf of Mexico have shown that the horizontally-
propagating sound can contain significant energy above the frequencies 
that airgun arrays are designed to emit (DeRuiter et al., 2006; Madsen 
et al., 2006; Tyack et al., 2006). Energy at frequencies up to 150 kHz 
was found in tests of single 60-in\3\ and 250-in\3\ airguns (Goold and 
Coates, 2006). Nonetheless, the predominant energy is at low 
frequencies.
    The strengths of airgun pulses can be measured in different ways, 
and it is important to know which method is being used when 
interpreting quoted source or received levels. Geophysicists usually 
quote peak-to-peak (p-p) levels, in bar-meters or (less often) dB re 1 
[mu]Pa.

[[Page 12547]]

Peak level (zero-to-peak [0-p]) for the same pulse is typically 
approximately 6 dB less. In the biological literature, levels of 
received airgun pulses are often described based on the average or rms 
level, where the average is calculated over the duration of the pulse. 
The rms value for a given airgun pulse is typically approximately 10 dB 
lower than the peak level and 16 dB lower than the p-p value (Greene, 
1997; McCauley et al., 1998, 2000). A fourth measure that is 
increasingly used is the Sound Exposure Level (SEL), in dB re 1 
[mu]Pa2s. Because the pulses, even when stretched by propagation 
effects (see below), are usually <1 s in duration, the numerical value 
of the energy is usually lower than the rms pressure level. However, 
the units are different.
    Because the level of a given pulse will differ substantially 
depending on which of these measures is being applied, it is important 
to be aware which measure is in use when interpreting any quoted pulse 
level. NMFS refers to rms levels when discussing levels of pulsed 
sounds that may harass marine mammals; these are the units used in this 
IHA notice. Specifics about the VSP airgun(s) and expected radii of 
various received rms sound levels are included in the acoustic modeling 
report of JASCO Applied Sciences (Attachment A of COP's application). 
The airgun array proposed for use will not exceed 760 in\3\. The VSP 
airgun operations differ from normal marine seismic surveys in that the 
airguns are fixed to one location (the drill rig), and a limited number 
of shots will be fired (a total of about 2 hrs of airgun activity per 
well, not including time required for ramp ups).
    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 drill rig throughout the 
2014 drilling season and will not be making trips between the shorebase 
and the offshore vessels (with the exception of the resupply transits). 
As noted earlier in this document and in Figure 3 of COP's application, 
the majority of the vessels will sit on standby mode approximately 5.5 
mi (9 km) upwind of the drill rig. 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 Chukchi Sea supports a diverse assemblage of marine mammals, 
including: bowhead, gray, beluga, killer, minke, humpback, and fin 
whales; harbor porpoise; ringed, ribbon, spotted, and bearded seals; 
narwhals (Monodon monoceros); polar bears (Ursus maritimus); and 
walruses (Odobenus rosmarus divergens; see Table 3 in COP's 
application). The bowhead, humpback, and fin whales are listed as 
``endangered'' under the Endangered Species Act (ESA) and as depleted 
under the MMPA. The ringed and bearded seals are listed as 
``threatened'' under the ESA. 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. 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 proposed IHA 
notice.
    Of these species, 12 are expected to occur in the area of COP's 
proposed operations. These species include: the bowhead, gray, 
humpback, minke, fin, killer, and beluga whales; harbor porpoise; and 
the ringed, spotted, bearded, and ribbon seals. Beluga, bowhead, gray, 
and killer whales, harbor porpoise, and ringed, bearded, and spotted 
seals are anticipated to be encountered more than the other four marine 
mammal species mentioned here. The marine mammal species that is likely 
to be encountered most widely (in space and time) throughout the period 
of the proposed drilling program is the ringed seal. Encounters with 
bowhead and gray whales are expected to be limited to particular 
seasons. Where available, COP used density estimates from peer-reviewed 
literature in the application. In cases where density estimates were 
not readily available in the peer-reviewed literature, COP used other 
methods to derive the estimates. NMFS reviewed the density estimate 
descriptions and documents and determined that they were acceptable for 
these purposes. The explanation for those derivations and the actual 
density estimates are described later in this document (see the 
``Estimated Take by Incidental Harassment'' section).
    The narwhal occurs in Canadian waters and occasionally in the 
Alaskan Beaufort Sea and the Chukchi Sea, but it is considered 
extralimital in U.S. waters 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). Due to the rarity of this species 
in the proposed project area and the remote chance it would be affected 
by COP's proposed Chukchi Sea drilling activities, this species is not 
discussed further in this proposed IHA notice.
    COP'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 COP 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 2011 SAR is available at: http://www.nmfs.noaa.gov/pr/pdfs/sars/ak2011.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;

[[Page 12548]]

     High frequency cetaceans (eight species of true porpoises, 
six species of river dolphins, Kogia, the franciscana, and four species 
of cephalorhynchids): functional hearing is estimated to occur between 
approximately 200 Hz and 180 kHz; and
     Pinnipeds in Water: functional hearing is estimated to 
occur between approximately 75 Hz and 75 kHz, with the greatest 
sensitivity between approximately 700 Hz and 20 kHz.
    As mentioned previously in this document, 12 marine mammal species 
(four pinniped and eight cetacean species) are likely to occur in the 
proposed drilling area. Of the eight cetacean species likely to occur 
in COP's project area, five are classified as low frequency cetaceans 
(i.e., bowhead, gray, humpback, minke, and fin whales), two are 
classified as mid-frequency cetaceans (i.e., beluga and killer whales), 
and one is classified as a high-frequency cetacean (i.e., harbor 
porpoise) (Southall et al., 2007).
    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 four 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 COP'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 COP's Chukchi Sea exploratory drilling program. Therefore, 
those industrial sounds are 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 the Chukchi Sea on marine mammals could involve both non-
acoustic and acoustic effects. Potential non-acoustic effects could 
result from the physical presence of the equipment and personnel. 
Petroleum development and associated activities introduce sound into 
the marine environment. Impacts to marine mammals are expected to 
primarily be acoustic in nature. Potential acoustic effects on marine 
mammals relate to sound produced by drilling activity, supply and 
support vessels on DP, and aircraft, as well as the VSP 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., 1995b):

[[Page 12549]]

    (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 wellbeing 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. (1995b) 
found that vessel noise does not seem to strongly affect pinnipeds that 
are already in the water. Richardson et al. (1995b) 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., 
1995b) 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., 1995b). 
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 
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., 1995b). 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

[[Page 12550]]

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., 1995b). 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 COP'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.
    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 since the late 1990s. 
To compensate and reduce masking, some mysticetes may alter the 
frequencies of their communication sounds (Richardson et al., 1995b; 
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. 
(1995b) 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., 1995b).
    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 COP'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. Moreover, the very 
small radius of the 120 dB isopleth of the drill rig (670 ft [210 m]) 
will reduce the possibility of masking even further. The larger 120 dB 
isopleth of the drill rig while a support vessel is in DP mode beside 
it (5 mi [8 km]) and over the VSP airguns (3 mi [5 km]) are also not 
anticipated to result in substantial or long-term masking effects as 
these activities will only occur for a short time during the entire 
open-water season (696 hrs and 2-4 hrs total, respectively).
(3) Behavioral Disturbance Reactions
    Behavioral responses to sound are highly variable and context-
specific. 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

[[Page 12551]]

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. (1995a) 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. However, icebreaking is not a component of COP's 
proposed operations.
    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. (1995a) 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 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

[[Page 12552]]

operations. In general, little or no response was observed in animals 
exposed at received levels from 90-120 dB re 1 [mu]Pa (rms). 
Probability of avoidance and other behavioral effects increased when 
received levels were from 120-160 dB re 1 [mu]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 percent 
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 [mu]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. 
(1995a) 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 Point 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., 1995a). 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 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-

[[Page 12553]]

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 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

[[Page 12554]]

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 percent 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 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

[[Page 12555]]

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 VSP surveys in 
the following section (``Potential Effects from VSP Activities'').

Potential Effects from VSP 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. 
Moreover, because of the extremely short time period over which airguns 
will be used during operations (a total of 2 hrs per well), masking is 
not anticipated to occur.
(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 [mu]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 VSP 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 1.44-3 mi (2.31-5 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

[[Page 12556]]

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 [mu]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, 2012). In any event, the brief exposures to sound 
pulses from the proposed airgun source (the airguns will only be fired 
for a period of 2 hrs 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 (p-p 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 
distances and durations, with no long-term effects on pinniped 
individuals or populations. Additionally, the airguns are only proposed 
to be used for a very short time during the entire exploration drilling 
program (approximately 2 hrs for each well, for a total of 4 hrs over 
the entire open-water season, which lasts for approximately 4 months, 
if both wells are drilled).
(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

[[Page 12557]]

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, COP 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 an 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]Pa2s; 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 source level of the drill rig will be below the 
180 dB threshold (O'Neill et al., 2012), TTS is not expected to occur 
in any marine mammal species 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 0.6 mi (920 m) and 525 ft (160 m), 
respectively, from the source. Because of the short duration that the 
airguns will be used (no more than 4 hrs 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,

[[Page 12558]]

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. Modeled source levels for a jack-up drill rig suggest that 
marine mammals located immediately adjacent to the rig 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 thresholds of 190 dB currently used for 
pinnipeds and 180 dB 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 sound pressure levels 
(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--Injury Criteria for Cetaceans and Pinnipeds Exposed to ``Discrete'' Noise Events (Either Single Pulses, Multiple Pulses, or Non-Pulses Within a
 24-Hr Period; Cited in Southall et al., 2007). This Table Reflects Thresholds Based on Studies Reviewed in Southall et al. (2007) But Do Not Influence
                                 the Estimation of Take in This Proposed IHA Notice as No Injury Is Anticipated To Occur
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                Single pulses                 Multiple pulses                             Non pulses
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                 Low-frequency cetaceans
--------------------------------------------------------------------------------------------------------------------------------------------------------
Sound pressure level..................  230 dB re 1 [mu]Pa (peak)      230 dB re 1 [mu]Pa (peak)      230 dB re 1 [mu]Pa (peak) (flat)
                                         (flat).                        (flat).
Sound exposure level..................  198 dB re 1 [mu]Pa\2\-s (Mlf)  198 dB re 1 [mu]Pa\2\-s (Mlf)  215 dB re 1 [mu]Pa\2\-s (Mlf)
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                 Mid-frequency cetaceans
--------------------------------------------------------------------------------------------------------------------------------------------------------
Sound pressure level..................  230 dB re 1 [mu]Pa (peak)      230 dB re 1 [mu]Pa (peak)      230 dB re 1 [mu]Pa (peak) (flat)
                                         (flat).                        (flat).
Sound exposure level..................  198 dB re 1 [mu]Pa\2\-s (Mlf)  198 dB re 1 [mu]Pa\2\-s (Mlf)  215 dB re 1 [mu]Pa\2\-s (Mlf)
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                High-frequency cetaceans
--------------------------------------------------------------------------------------------------------------------------------------------------------
Sound pressure level..................  230 dB re 1 [mu]Pa (peak)      230 dB re 1 [mu]Pa (peak)      230 dB re 1 [mu]Pa (peak) (flat)
                                         (flat).                        (flat).
Sound exposure level..................  198 dB re 1 [mu]Pa\2\-s (Mlf)  198 dB re 1 [mu]Pa\2\-s (Mlf)  215 dB re 1 [mu]Pa\2\-s (Mlf)
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                  Pinnipeds (in water)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Sound pressure level..................  218 dB re 1 [mu]Pa (peak)      218 dB re 1 [mu]Pa (peak)      218 dB re 1 [mu]Pa (peak) (flat)
                                         (flat).                        (flat).
Sound exposure level..................  186 dB re 1 [mu]Pa\2\-s (Mpw)  186 dB re 1 [mu]Pa\2\-s (Mpw)  203 dB re 1 [mu]Pa\2\-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; 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

[[Page 12559]]

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 level of the drill rig 
is not loud enough to induce PTS or 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 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

[[Page 12560]]

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 drill rigs. Sounds produced by 
airgun arrays are broadband impulses with most of the energy below 1 
kHz, and the low-energy continuous sounds produced by drill rigs have 
most of the energy between 20 and 1,000 Hz. Additionally, the non-
impulsive, continuous sounds produced by the jack-up rig proposed to be 
used by COP does 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.

Oil Spill Response Preparedness and Potential Impacts of an Oil Spill

    As noted above, the specified activity involves the drilling of 
exploratory wells and associated activities in the Chukchi Sea during 
the 2012 open-water season. The impacts to marine mammals that are 
reasonably expected to occur will be acoustic in nature. The likelihood 
of a large or very large oil spill occurring during COP's proposed 
exploratory drilling program is remote. 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). BOEM's Supplemental Environmental Impact 
Statement for the Chukchi Sea Oil and Gas Lease Sale 193 (BOEM, 2011) 
provides a discussion of the extremely low likelihood of an oil spill 
occurring (available on the Internet at: http://www.boem.gov/About-BOEM/BOEM-Regions/Alaska-Region/Environment/Environmental-Analysis/OCS-EIS/EA-BOEMRE-2011-041.aspx). For more recent updates on occurrence 
rates for offshore oil spills from drilling platforms, including spills 
greater than or equal to 1,000 barrels (bbls) and greater than or equal 
to 10,000 bbls, we refer to the BOEM-funded study of McMahon-Anders et 
al. (2012). However, this study did not focus solely on the Alaskan 
OCS. Another BOEM-directed study discusses most recent oil spill 
occurrence estimators and their variability for the Beaufort and 
Chukchi Seas for various sizes of spills as small as 50 bbls (Bercha, 
2011). Bercha (2011) notes that because of the difference in oil spill 
indicators between non-Arctic OCS areas and the Beaufort and Chukchi 
Seas OCS areas, the non-Arctic areas are likely to result in a somewhat 
higher oil spill occurrence probability than comparable developments in 
the Chukchi or Beaufort Seas.
    COP will have various measures and protocols in place that will be 
implemented to prevent oil releases from the wellbore, such as:
     Using information from previous wells in addition to 
recent data collected from 3D seismic and shallow hazard surveys, where 
applicable, to increase knowledge of the subsurface environment;
     Using skilled personnel and providing them with project-
specific training. Implementing frequent drills to keep personnel 
alert;
     Implementation of visual and automated procedures for the 
early detection of a spill:

[[Page 12561]]

    [cir] The drilling operation will be monitored continuously by Pit-
Volume Totalizer equipment and visual monitoring of the mud circulating 
system.
    [cir] Alarms will be sounded if there is a significant volume 
increase of drilling mud in the pits due to an influx into the 
wellbore.
    [cir] Multiple walk-through inspections of the rig are performed 
every day by each crew to inspect and verify all control systems are 
functioning properly.
    [cir] Mobile Offshore Drilling Unit's (MODU) Central Control & 
Radio Room monitors all safety aspects of the rig and is manned 24 hrs 
per day by qualified rig personnel.
    [cir] Established emergency shutdown philosophies will be 
documented in the Contractor's Operations manuals and the crews will be 
trained accordingly. An emergency shutdown can be initiated manually by 
operators at the instrument/control panels or automatically under 
certain conditions.
     Maintaining a minimum of two barriers; the jack-up rig has 
the capability of utilizing advanced well control barriers:
    [cir] Surface blow out preventer (BOP) located on the rig in a 
place that is easily accessible. This BOP can close in well on drill 
pipe or open hole.
    [cir] Thick walled high strength riser designed to contain full 
well pressure.
    [cir] Pre-Positioned Capping Device (PCD) will be installed above 
the wellhead on the sea floor. The PCD can keep the well isolated with 
pressure containment, even if the rig is moved off location. The PCD 
can be triggered remotely from the drill rig or from support vessels.
    Mechanical containment and recovery is COP's primary form of 
response. Actual spill response decisions depend on safety 
considerations, weather, and other environmental conditions. It is the 
discretion of the Incident Commander and Unified Command to select any 
sequence, response measure, or take as much time as necessary, to 
employ an effective response. COP's spill response fleet is mobile and 
capable of responding to incidents affecting open-water, nearshore, and 
shoreline environments. Offshore spill response would be provided by 
the following vessels:
     Oil Spill Response Vessel (OSRV), the primary offshore oil 
spill response platform, located within about 5.5 mi (9 km) of the 
drilling rig;
     Offshore Supply Vessel (OSV), a vessel of opportunity 
response platform, located within about 5.5 mi (9 km) of the drilling 
rig;
     Four workboats, two are located on the OSRV and two on the 
OSV; and
     One Oil Spill Tanker (OST), with a storage capacity of at 
least 520,000 barrels, also located within about 5.5 mi (9 km) from the 
drilling rig.
    Alaska Clean Seas personnel will be stationed on OSRV, OSV, and the 
drill rig. OSRV is the primary spill response vessel; it will also be 
used to support refueling of the jack-up rig. In the event of an 
emergency, OSV will provide oil spill response and fast response craft 
capability near the ware vessel. During non-emergency operations, OSV 
will provide operational drill rig support, including standby support 
during vessel refueling operations. From the standby locations, it will 
take about 30 min for the vessels to arrive at the rig.
    Spill response support for nearshore operations will be located 
about 5.5 mi (9 km) from the drill rig location and approximately 5 mi 
(8 km) offshore of Wainwright. Nearshore spill response operations are 
provided by the following vessels:
     One Oil Spill Response Barge (OSRB) and tug with a storage 
capacity of 40,000 bbls;
     Four workboats, located on the OSRB;
     One large landing craft, located adjacent to the OSRB; and
     Four 32-foot shallow draft landing craft located on the 
large landing craft.
    The OSRB and large landing craft are designed to carry and deploy a 
majority of the nearshore and onshore spill response assets. In the 
event of a spill, additional responders would be mobilized to man the 
OSRB, large landing craft, and other support vessels. From 5 mi (8 km) 
offshore of Wainwright it will take about 24 hrs for the OSRB to arrive 
at the rig, assuming a travel speed of 5 knots and including 
notification time. However, because this barge is equipped primarily 
for nearshore response, it is unlikely to be needed offshore near the 
rig.
    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 COP's specified 
activity for which NMFS is proposing to authorize take, 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 cetaceans 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 cetaceans 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 animals. 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

[[Page 12562]]

(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 
conclude 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 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 in the Gulf of Mexico 
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 cetaceans in open water are likely to be minimal, 
but there could be effects on cetaceans 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 COP 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

[[Page 12563]]

subject to prolonged contamination. However, the autumn migration 
through the Chukchi Sea extends over several weeks, and some of the 
whales travel along routes north or inland 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 the Devils Paw prospect in 
the Chukchi Sea, thereby reducing the likelihood of contact with 
spilled oil.
    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, humpback 
and fin whales are only sighted in the Chukchi Sea in small numbers in 
the summer, as this is thought to be the extreme northern edge of their 
range. Therefore, impacts to these species from an oil spill would be 
extremely limited.

Potential Effects of Oil on Pinnipeds

    Ice 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 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. 
However, COP's activities will not occur during pupping season or when 
lairs are built.
(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

[[Page 12564]]

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.

Potential Effects Conclusion

    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 drill rig and the airguns). 
However, other potential impacts are also possible to the surrounding 
habitat from physical disturbance, discharges, 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 Area

    All 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 in the Beaufort Sea 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 200 mi [322 km] east of COP's proposed drill 
sites in the Chukchi Sea) 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 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.). However, by the time most bowhead whales reach the 
Chukchi Sea (October), they will likely no longer be feeding, or if it 
occurs it will be very limited. The location near Point Barrow is 
currently under intensive study as part of the BOWFEST program 
(BOWFEST, 2011).
    Beluga whales feed on a variety of fish, shrimp, squid, and octopus 
(Burns and Seaman, 1985). Like several of the other species in the 
area, harbor porpoise feed on demersal and benthic species, mainly 
schooling fish and cephalopods. Killer whales from resident stocks 
primarily feed on salmon while killer whales from transient stocks feed 
on other marine mammals, such as harbor seals, harbor porpoises, gray 
whale calves and other pinniped and cetacean species.
    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). Based on data collected from recent Aerial Survey of 
Arctic Marine Mammals (ASAMM, formerly referred to as BWASP for the 
Beaufort Sea or COMIDA for the Chukchi Sea) flights (Clarke and 
Ferguson, 2010; Clarke et al., in prep.; Clarke et al., 2011; Clarke et 
al., 2012) three primary feeding grounds have been identified as 
currently used by gray whales in the Chukchi Sea: (1) Between Point 
Barrow and Icy Cape within approximately 56 mi (90 km) of shore; (2) 
nearshore from south of Point Hope to east of Cape Lisburne; and (3) in 
the south-central Chukchi Sea. These latter two locations are located 
substantial distances from COP's operating area. With the exception of 
vessel transits, the first feeding area is also located outside of 
COP's drilling area.
    Three other baleen whale species may occur in the proposed project 
area, although likely in very small numbers: minke, humpback, and fin 
whales. Minke whales opportunistically feed on crustaceans (e.g., 
krill), plankton (e.g., copepods), and small schooling fish (e.g., 
anchovies, dogfish, capelin, coal fish, cod, eels, herring, mackerel, 
salmon, sand lance, saury, and wolfish) (Reeves et al., 2002). Fin 
whales tend to feed in northern latitudes in the summer months on 
plankton and shoaling pelagic fish (Jonsgard, 1966a,b). Like many of 
the other species in the area, humpback whales primarily feed on 
euphausiids, copepods, and small schooling fish (e.g., herring, 
capelin, and sand lance) (Reeves et al., 2002). However, the primary 
feeding grounds for these species do not occur in the northern Chukchi 
Sea.
    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

[[Page 12565]]

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). The northeastern 
Chukchi Sea supports a higher biomass of benthic organisms than do 
surrounding areas (Grebmeier and Dunton, 2000). Some benthic-feeding 
marine mammals, such as walruses and gray whales, take advantage of the 
abundant food resources and congregate in these highly productive 
areas. Harold and Hanna Shoals are two known highly productive areas in 
the Chukchi Sea rich with benthic animals.
    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). Additionally, kelp beds 
occur in at least two areas in the nearshore areas of the Chukchi Sea 
(Mohr et al., 1957; Phillips et al., 1982; Phillips and Reiss, 1985), 
but they are located within about 15.5 mi (25 km) of the coast, which 
is much closer nearshore than COP's proposed activities.

Potential Impacts From Seafloor Disturbance on Marine Mammal Habitat

    There is a possibility of seafloor disturbance or increased 
turbidity in the vicinity of the drill sites. Seafloor disturbance 
could occur with bottom founding of the drill rig legs and anchoring 
system and also with the anchoring systems of support vessels. These 
activities could lead to direct effects on bottom fauna, through either 
displacement or mortality. Increase in suspended sediments from 
seafloor disturbance also has the potential to indirectly affect bottom 
fauna and fish. The amount and duration of disturbed or turbid 
conditions will depend on sediment material.
    Placement of the drill rig onto the seabed will include firm 
establishment of its legs onto the seafloor. No anchors are required to 
be deployed for stabilization of the rig. Displacement or mortality of 
bottom organisms will likely occur in the area covered by the spud can 
of the legs. The area of seabed that will be covered by these spud cans 
is about 2,165 ft \2\ (200 m \2\) per spud, which is a total of 6,500 
ft \2\ (600 m \2\) for three legs or 8,660 ft \2\ (800 m\2\) for four 
legs. The mean abundance of benthic organisms in the Klondike area was 
about 800 individuals/m \2\ (Blanchard et al., 2010) and consisted 
mostly of polychaete worms and mollusks. The drill rig is a temporary 
structure that will be removed at the end of the field season. Because 
of the placement of the spud cans, benthic organisms are expected to 
decolonize the relatively small disturbed patches from adjacent areas. 
Impacts to marine mammals from such disturbance are anticipated to be 
inconsequential.
    Placement and demobilization of the drill rig can lead to an 
increase in suspended sediment in the water column, with the potential 
to affect zooplankton, including fish eggs and larvae. The magnitude of 
any impact strongly depends on the concentration of suspended 
sediments, the type of sediment, the duration of exposure, and also of 
the natural turbidity in the area. Fish eggs and larvae have been found 
to exhibit greater sensitivity to suspended sediments (Wilber and 
Clarke, 2001) and other stresses than adult fish, which is thought to 
be related to their relative lack of motility (Auld and Schubel, 1978). 
Sedimentation could potentially affect fish by causing egg morbidity of 
demersal fish feeding near or on the ocean floor (Wilber and Clarke, 
2001). However, the increase in suspended sediments from drill rig 
placement, demobilization and anchor handling is very limited, 
localized and temporary, and will likely be indistinguishable from 
natural variations in turbidity and sedimentation. No impacts on 
zooplankton are therefore expected considering the high inter-annual 
variability in abundance and biomass in the Devils Paw Prospect, 
influenced by timing of sea ice melt, water temperatures, northward 
transport of water masses, and nutrients and chlorophyll (Hopcroft et 
al., 2011).
    Benthic organisms inhabiting the Devils Paw Prospect will likely be 
displaced or smothered. However, due to the limited area and duration 
of the proposed drilling program and because the area is mainly 
characterized as a pelagic system (Day et al., 2012) with a low density 
of benthic feeding marine mammals, the limited loss or modification of 
habitat is not expected to result in impacts to marine mammals or their 
populations. Less than 0.0000001 percent of the fish habitat in the 
Lease Sale 193 area would be directly affected by the bottom founding 
of the drill rig legs and anchoring.

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

[[Page 12566]]

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 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 COP'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 jack-up rig would extend 
approximately 33 ft [10 m] approximately 0.4 mi [710 m] when a support 
vessel is in DP mode next to the drill rig; therefore, fish would need 
to be in close proximity to the drill rig 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 activities are not expected to 
be necessary throughout most of the drilling season, so impacts from 
that activity would occur less frequently than sound from the drill 
rig. Sounds generated by drilling and ice-management are generally low 
frequency and within the frequency range detectable by most fish.
    COP also proposes to conduct seismic surveys with an airgun array 
for a short period of time during the drilling season (a total of 
approximately 2-4 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;

[[Page 12567]]

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 drill 
rig 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 jack-up 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 33 ft (10 m) of the 
drill rig during drilling. 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 
COP'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, which is 
not expected to result in reduced prey abundance.
    Some mysticetes, including bowhead whales, feed on concentrations 
of zooplankton. Bowhead whales primarily feed off Point Barrow in 
September and October. 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. 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. However, Barrow is located approximately 200 
mi (322 km) east of COP's Devils Paw prospect. Impacts on zooplankton 
behavior are predicted to be inconsequential. Thus, bowhead whales 
feeding off Point Barrow would not be adversely affected.
    Gray whales are bottom feeders and suck sediment and the benthic 
amphipods that are their prey from the seafloor. The species primary 
feeding habitats are in the northern Bering Sea and Chukchi Sea 
(Nerini, 1984; Moore et al., 1986; Weller et al., 1999). As noted 
earlier in this document, most gray whale feeding locations in the 
Chukchi Sea are located closer to shore. Several of the primary feeding 
grounds are located much further south in the Chukchi Sea than COP's 
proposed activity area. Additionally, Yazvenko et al. (2007) studied 
the impacts of seismic surveys off Sakhalin Island, Russia, on feeding 
gray whales and found that the seismic activity had no measurable 
effect on bottom feeding gray whales in the area.

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 on 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).
    Drilling muds and cuttings discharged to the seafloor can lead to 
localized increased turbidity and increase in background concentrations 
of barium and occasionally other metals in sediments and may affect 
lower trophic organisms. Drilling muds are composed primarily of 
bentonite (clay), and the toxicity is therefore low. Heavy metals in 
the mud may be absorbed by benthic organisms, but studies have shown 
that heavy metals do not bio-magnify in marine food webs (Neff et al., 
1989). There have been no field monitoring studies of effects of water-
based muds and cuttings discharges on biological communities of the 
Alaskan Chukchi Sea and only a few in the development area of the 
Alaskan Beaufort Sea (Neff et al., 2010). However, the results of these 
studies are consistent with the results of many more comprehensive 
microcosm and ecological investigations near cuttings discharge sites 
in cold-water environments of the North Sea, the Barents Sea, off 
Sakhalin Island in the Russian Far East, and in the Canadian Beaufort 
Sea off the Mackenzie River (Neff et al., 2010). All the studies show 
that water-based muds and cuttings discharges have no, or minimal and 
very short-lived effects on zooplankton communities. This might, in 
part, be due to the large inter-annual differences observed in the 
planktonic communities. In the Chukchi Sea the inter-annual variability 
of zooplankton biomass and community structure is influenced by 
differences in ice melt timing, water temperatures, and the northward 
rate of transport of water masses, and nutrients and chlorophyll 
(Hopcroft et al., 2011). Effects on benthic communities are nearly 
always restricted to a zone within about 328 to 492 ft (100 to 150 m) 
of the discharge, where cuttings accumulations are greatest.
    Discharges and drill cuttings could impact fish by displacing them 
from the affected area. Additionally, sedimentation could impact fish, 
as demersal fish eggs could be smothered if discharges occur in a 
spawning area during the period of egg production. However, this is 
unlikely in deeper offshore locations, and no specific demersal fish 
spawning locations have been identified at the Devils Paw well 
locations. The most abundant and trophically important marine fish, the 
Arctic cod, spawns with planktonic eggs and larvae under the sea ice 
during winter and will therefore have little exposure to discharges. 
Based on this information, drilling muds and cutting wastes are not 
anticipated to have long-term impacts to marine mammals or their prey.

Potential Impacts From Drill Rig Presence

    The horizontal dimensions of the jack-up rig will be approximately 
230 x 225 ft (70 x 68 m). Maximum dimension of one leg spud can, which 
is the part on the seafloor, is about 60 ft (18 m). The dimensions of 
the drill rig (less than one football field on either side) are 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 occur prior to the beginning of COP's 
proposed exploratory drilling program. Moreover, any deflection of 
bowhead whales or other marine mammal species

[[Page 12568]]

due to the physical presence of the drillship or its support vessels 
would be very minor. The drill rig'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 greatly from their typical 
migratory route. Also, even if animals may deflect because of the 
presence of the drill rig, the Chukchi Sea is much larger in size than 
the length of the drill rig (many dozens to hundreds of miles vs. less 
than one football field), and animals would have other means of passage 
around the drill rig. While there are other vessels that will be on 
location to support the drill rig, most of those vessels will remain 
within a 5.5 mi (9 km) of the drill rig (with the exception of the ice 
management vessels which will remain approximately 75 mi [121 km] from 
the drill rig when conducting ice reconnaissance). In sum, the physical 
presence of the drill rig is not likely to cause a significant 
deflection to migrating marine mammals.

Potential Impacts From an Oil Spill

    Lower trophic organisms and fish species are primary food sources 
for Arctic marine mammals. However, as noted earlier in this document, 
the offshore areas of the Chukchi Sea are not primary feeding grounds 
for many of the marine mammals that may pass through the area. 
Therefore, impacts to lower trophic organisms (such as zooplankton) and 
marine fishes from an oil spill in the proposed drilling area would not 
be likely to have long-term or significant consequences to marine 
mammal prey. Impacts would be greater if the oil moves closer to shore, 
as many of the marine mammals in the area have been seen feeding at 
nearshore sites (such as bowhead and gray whales).
    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 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 drill rig. Based on extensive 
satellite data analyses of historic and present ice conditions in the 
northeastern Chukchi Sea, it is unlikely that hazardous ice will be 
present in the vicinity of the jack-up rig. COP therefore expects that 
physical management of ice will not be required. However, to ensure 
safe drilling operations, COP has developed an Ice Alerts Plan designed 
to form an integral part of the drilling operations. The Ice Alerts 
Plan contains procedures that will allow early predictions in advance 
of potential hazardous ice that could cause damage if it were to come 
into contact with the jack-up rig.
    The first method of prevention is to identify the presence of 
hazardous ice at a large distance from the rig (tens of miles). The ice 
edge position will be tracked in near real time using observations from 
satellite images and from vessels. Generally, the ice management vessel 
will remain within 5.5 mi (9 km) of the drill rig, unless deployed to 
investigate migrating ice floes. When investigating ice, vessels will 
likely not travel farther than 75 mi (121 km) from the rig. The Ice 
Alerts Plan contains procedures for determining how close hazardous ice 
can approach before the well needs to be secured and the jack-up moved. 
This critical distance is a function of rig operations at that time, 
the speed and direction of the ice, the weather forecast, and the 
method of ice management.
    Based on available historical and more recent ice data, there is 
low probability of ice entering the drilling area during the open-water 
season. However, if hazardous ice is on a trajectory to approach the 
rig, the ice management vessel will be available to respond. One option 
for responding is to use the vessel's fire monitor (water cannon) to 
modify the trajectory of the floe. Another option is to redirect the 
ice by applying pressure with the bow of the ice management vessel, 
slowly pushing the ice away from the direction of the drill rig. At 
these slow speeds, the vessel uses low power and slow propeller 
rotation speed, thereby reducing noise generation from propeller 
rotation effects in the water. In case the jack-up rig needs to be 
moved due to approaching ice, the support vessels will tow the rig to a 
secure location.
    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 activities be 
necessary during the proposed drilling program, COP would only manage 
pack ice. Landfast ice would not be present during COP'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 COP plans to conclude drilling by 
October 31, COP's activities would not impact ringed seal lairs or 
habitat needed for breeding and pupping in the Chukchi Sea. Aerial 
surveys in the eastern Chukchi Sea conducted in late May-early June 
1999-2000 found that ringed seals were four to ten times more abundant 
in nearshore fast and pack ice environments than in offshore pack ice 
(Bengtson et al., 2005). Ringed seals can be found on the pack ice 
surface in the late spring and early summer in the northern Chukchi 
Sea, the latter part of which may overlap with the start of COP'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 from mid-March 
through early May (several months prior to the start of COP's 
operations). Bearded seals require sea ice for molting during the late 
spring and summer period. Because this species feeds on benthic prey, 
bearded seals occur over the pack ice front over the Chukchi Sea shelf 
in summer (Burns and Frost, 1979) but were not associated with the ice 
front when it receded over deep water (Kingsley et al., 1985).
    The spotted seal does not breed in the Chukchi Sea. Spotted seals 
molt most intensely during May and June and then move to the coast 
after the sea ice has melted. Ribbon seals are not known to breed in 
the Chukchi Sea. From July-October, when sea ice is absent, the ribbon 
seal is entirely pelagic, and its distribution is not well known 
(Burns, 1981; Popov, 1982). 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 COP's drilling program since these 
life functions do not occur in the proposed project area or at the same 
time as COP's operations. For ringed seals, ice management activities 
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

[[Page 12569]]

landfast ice, which will not be impacted by COP's activity.
    Based on the preceding discussion of potential types of impacts to 
marine mammal habitat, overall, the proposed specified activity is not 
expected to cause significant impacts on habitats used by the marine 
mammal species in the proposed project area or on the food sources that 
they utilize.

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 
mitigation measures proposed for implementation by COP. Later in this 
document in the ``Proposed Incidental Harassment Authorization'' 
section, NMFS lays out the proposed conditions for review, as they 
would appear in the final IHA (if issued).
    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 would likely occur (see Southall et al., 2007). 
With respect to Level B harassment, NMFS' practice has been to apply 
the 120 dB re 1 [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. As noted earlier in 
this document and in O'Neill et al. (2012), the source level of the 
drill rig does not meet the criteria requiring exclusion zones. 
Therefore, mitigation measures similar to those required for seismic 
surveys are not proposed for the drilling only portion of the program.

General Mitigation Measures

    COP proposes to implement several mitigation measures regarding 
operation of vessels and aircraft. These measures would limit speed and 
vessel movements in the presence of marine mammals and restrict flight 
altitudes except during takeoff, landing, and in emergency situations. 
The exact measures (as proposed) can be found later in this document in 
the ``Proposed Incidental Harassment Authorization'' section.

VSP Airgun Mitigation Measures

    COP proposes to implement standard mitigation measures used in 
previous seismic surveys, including ramp-ups, power downs, and 
shutdowns. The received sound levels have been estimated using an 
acoustic model (see Attachment A of COP's IHA application). These 
modeled distances will be used to establish exclusion zones for the 
implementation of the mitigation measures during the first VSP data 
acquisition run. The exclusion zones (i.e., 180 dB rms for cetaceans 
and 190 dB rms for pinnipeds) might change for subsequent VSP data 
acquisition runs after the distances have been verified based on 
acoustic field measures (more details are provided in the ``Proposed 
Monitoring and Reporting'' section later in this document). The VSP 
data acquisition runs will start during daylight hours.
    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.
    Ramp-up will begin with the smallest airgun in the array. COP 
intends to double the number of operating airguns at 1-min intervals. 
Since the airgun operation at each geophone station only lasts about 1 
min, this interval should be adequate and also reduces the total 
emission of airgun sounds. During the ramp-up, observers will scan the 
exclusion zone for the full airgun array for presence of marine 
mammals.
    The entire exclusion zone must be visible during the 30-minute 
lead-in to a full ramp up. If the entire exclusion zone is not visible, 
then ramp up from a cold start cannot begin. If a marine mammal(s) is 
sighted within the exclusion zone during the 30-minute watch prior to 
ramp up, ramp up will be delayed until the marine mammal(s) is sighted 
outside of the applicable exclusion zone or the animal(s) is not 
sighted for at least 15 minutes for small odontocetes and pinnipeds or 
30 minutes for baleen whales. No ramp-up of airguns will be conducted 
between 1-min airgun operations at subsequent geophone stations (i.e., 
following the relocation of the geophone within the wellbore) if the 
duration of the relocation is 30 min or less, if the exclusion zone of 
the full array has been visible, and no marine mammals have been 
sighted within the applicable exclusion zones or during poor visibility 
or darkness if one airgun has been operating continuously during the 
geophone relocation period.
    A power down is the immediate reduction in the number of operating 
energy sources from all firing to some smaller number. A shutdown is 
the immediate cessation of firing of all energy sources. The arrays 
will be immediately powered down whenever a marine mammal is sighted 
approaching close to or within the applicable exclusion zone of the 
full arrays but is outside the applicable exclusion zone of the single 
source. If a marine mammal is sighted within the applicable exclusion 
zone of the single energy source, the entire array will be shutdown 
(i.e., no sources firing). The same 15 and 30 minute sighting times 
described for ramp up also apply to starting the airguns again after 
either a power down or shutdown.

Oil Spill Response Plan

    In accordance with BSEE regulations, COP has developed an Oil Spill 
Response Plan (OSRP) for its Chukchi Sea exploration drilling program. 
The OSRP is currently under review by DOI and will be shared with other 
agencies, including NOAA, for their review as well. A final 
determination on the adequacy of the COP's OSRP is expected prior to 
the start of drilling operations. In the unlikely event of a large or 
very large oil spill, COP would work with the Unified Command, 
including representatives of the local communities, to use methods that 
would mitigate impacts of a response on subsistence activities.

Proposed Mitigation Measure Conclusion

    NMFS has carefully evaluated COP'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

[[Page 12570]]

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 COP

    The monitoring plan proposed by COP can be found in the Marine 
Mammal Monitoring and Mitigation Plan (4MP; Attachment B of COP'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) Visual Observers
    The distances at which received sound levels occur that have the 
potential to cause Level B behavioral harassment (120 dB rms for 
continuous sounds) are 689 ft (210 m) for drilling only and about 5 mi 
(8 km) for drilling and support vessel activity (O'Neill et al., 2011). 
Protected Species Observers (PSOs) at the drill rig will monitor this 
zone, using big eye binoculars, documenting presence and behavior of 
marine mammals during these activities. At least four PSOs will be 
located on the drill rig to collect marine mammal data during drilling 
and resupply operations. The PSOs will also collect data and implement 
mitigation measures during the VSP data acquisition runs. Two PSOs will 
be present on the ice management vessel, which will be on standby 
within 5.5 mi (9 km) of the drill rig, except when conducting ice 
reconnaissance.
    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 COP 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 ``Big-eye'' binoculars. Personnel on the bridge will 
assist the PSOs in watching for marine mammals.
    When a marine mammal sighting is made, the following information 
will be recorded:
     Species, group size, number of juveniles (where possible), 
behavior when first sighted and after initial sighting, heading (if 
consistent), bearing and distance from PSO, apparent reaction to 
activities, and pace;
     Time, location, vessel speed and activity (where 
applicable), sea state, ice cover, visibility, and sun glare;
     Positions of other vessels in the vicinity of the PSO 
location or the position and distance of the jack-up rig from the 
vessel, where applicable; and
     Ship's position and speed (for PSO on vessels) or the 
drill rig activity (i.e. drilling or not, for PSOs on the drill rig), 
water depth, sea state, ice cover, visibility, and sun glare during the 
watch.
    During helicopter transfers to and from the drill rig, PSOs will 
observe and record marine mammal sightings according to a standardized 
protocol.
    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) Acoustic Monitoring
    Sound levels from drilling activities and vessels are expected to 
vary significantly with time due to variations in the operations and 
the different types of equipment used at different times onboard the 
drill rig. The goals of the project-specific acoustic monitoring 
program are to (1) Quantify the absolute sound levels produced by 
drilling and to monitor their variations with time, distance and 
direction from the drill rig; (2) measure the sound levels produced by 
vessels operating in support of drilling operations; (3) measure sounds 
from VSP data acquisition runs; and (4) detect vocalization of marine 
mammals. To accomplish these goals, implementation of autonomous 
monitoring using bottom-founded acoustic recorders is proposed during 
exploration drilling.
    COP proposes that monitoring of sound levels from drilling and 
vessel activities, as well as from the VSP airguns, will occur on a 
continuous basis throughout the entire drilling season with a set of 
bottom-founded acoustic recorders. At least four recorders will be 
deployed on the seafloor at distances of approximately 0.31 mi (0.5 
km), 0.62 mi (1 km), 2.5 mi (4 km), and 6.2 mi (10 km) from the drill 
rig. The bottom-founded recorders will be set to record at a sample 
rate of 16 or 32 kilohertz (kHz), providing useful acoustic bandwidth 
to 8 or 16 kHz. Calibrated reference hydrophones will be used for the 
measurements, capable of measuring absolute broadband sound levels 
between 90 and 200 dB re [mu]Pa rms. The deployment of the bottom-
founded acoustic monitoring equipment will occur just prior to 
placement of the drill rig at the location(s) where COP intends to 
drill an exploration well.

[[Page 12571]]

After the first VSP data acquisition run, the recorders will be 
retrieved and the data downloaded. Recorders will then be deployed 
again and will remain in place until completion of all drilling 
activities. The three main objectives of the bottom-founded autonomous 
hydrophones are: (1) Provide long duration recordings capturing sound 
levels of all operations performed at the drill rig and of all vessel 
movements in the vicinity through post-season analyses; (2) calculate 
source levels, and distances to sound levels of 160 dB and 120 dB re 
1[mu]Pa rms from drilling activities and vessels supporting the drill 
rig and distances to 160 dB from VSP airgun sounds; and (3) record 
marine mammal vocalizations during the drilling season to be compared 
with visual observations during post-season analyses.
    Additional details on data analysis for the types of monitoring 
described here (i.e., visual PSO and acoustic) can be found in the 4MP 
in COP'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 convened an independent peer review panel, comprised of 
experts in the fields of marine mammal ecology and underwater 
acoustics, to review COP's 4MP for Offshore Exploration Drilling in the 
Devils Paw Prospect, Chukchi Sea, Alaska. The panel met on January 8-9, 
2013. NMFS anticipates receipt of the panel's report containing their 
recommendations on the 4MP shortly. 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) Sound Source Verification and Characterization Report
    COP will be required to submit a report of the acoustic monitoring 
results noting the source levels and received levels (in 10 dB 
increments down to 120 dB) from the jack-up rig, support vessels (also 
while in DP mode), and of the VSP airgun array. Additional information 
to be reported is contained in COP's 4MP. Initial measurements must be 
provided to NMFS within 120 hr of collection and analysis of those 
data. This report will specify the distances of the exclusion zones 
that were adopted for the VSP data acquisition runs. Prior to 
completion of these measurements, COP will use the radii outlined in 
their application and elsewhere in this document.
(2) Technical Reports
    The results of COP's 2014 Chukchi Sea 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. COP proposes that the Technical Reports 
will include: (1) Summaries of monitoring effort (e.g., total hours of 
effort for rig-based observations or observations from the ice 
management vessel when stationary and total kilometer of effort for 
non-stationary vessel-based observations); (2) effective area of 
observation and marine mammal distribution through study period 
(accounting for sea state and other factors affecting visibility and 
detectability of marine mammals); (3) analyses of the effects of 
various factors influencing detectability of marine mammals (e.g., sea 
state, number of observers, and fog/glare); (4) species composition, 
occurrence, and distribution of marine mammal sightings, including 
date, numbers, age/size/gender categories (if determinable), group 
sizes, and ice cover; (5) sighting rates of marine mammals during 
periods with and without drilling activities (and other variables that 
could affect detectability); (6) initial sighting distances and 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 
drill rig and support vessels versus drilling state; and (10) estimates 
of take by harassment.
    The initial technical report is due to NMFS within 90 days of the 
completion of COP's Chukchi 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) Notification of Injured or Dead Marine Mammals
    COP 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, COP may or may not be 
required to stop operations upon such a sighting. COP 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 describing what 
COP 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 drill rig, associated support vessels in DP 
mode, and the airgun array are expected to harass, through behavioral 
disturbance, affected marine mammal species or stocks. Additional 
disturbance to marine mammals may result from aircraft overflights and 
visual disturbance of the drill rig 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., 1995b).

[[Page 12572]]

As discussed earlier in this document, NMFS estimates that COP'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 COP'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 source level for the drill rig is 
estimated to be below 170 dB re 1 [mu]Pa (rms), no injury or mortality 
of marine mammals is anticipated as a result of COP's proposed 
exploratory drilling program.
    For continuous sounds, such as those produced by drilling 
operations and during DP, 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 VSP surveys, NMFS uses a 
received level of 160-dB (rms) to indicate the onset of Level B 
harassment. COP provided calculations for the 120-dB isopleths produced 
by the jack-up rig and the support vessels in DP and then used those 
isopleths to estimate takes by harassment. Additionally, COP provided 
calculations for the 160-dB isopleth produced by the airgun array and 
then used that isopleth to estimate takes by harassment. COP 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.
    COP has requested authorization to take bowhead, gray, fin, 
humpback, minke, killer, and beluga whales, harbor porpoise, and 
ringed, spotted, bearded, and ribbon seals incidental to exploration 
drilling, support vessels operating in DP mode, ice management, and VSP 
activities.
    COP's density estimates are based on the best available peer 
reviewed scientific data, when available. In cases where the best 
available data were collected in regions, habitats, or seasons that 
differ from the proposed survey activities, adjustments to reported 
population or density estimates were made to account for these 
differences insofar as possible. In cases where the best available peer 
reviewed data were based on data from more than a decade old, more 
recent information was used. Species abundance information in the 
northeastern Chukchi Sea from the 2008-2010 COMIDA (now referred to as 
ASAMM) marine mammal aerial surveys (Clarke and Ferguson, 2010; Clarke 
et al., 2011) and the 2008-2010 vessel-based Chukchi Sea Environmental 
Studies Program (CSESP; Aerts et al., 2011) contain current knowledge 
of some whale and seal species. The data from the COMIDA aerial survey 
have undergone several reviews, so although not officially peer 
reviewed, these recent abundance and distribution data were determined 
to be more representative than older peer reviewed publications for 
bowhead and gray whales. The CSESP data are as of yet preliminary so 
are presently only used as a comparison to available peer reviewed 
data, unless no other information was available. In those cases the 
CSESP data were used to estimate densities. After reviewing the density 
estimates, NMFS determined that the data used are appropriate.
    Because most cetacean species show a distinct seasonal 
distribution, density estimates for the northeastern Chukchi Sea have 
been derived for two time periods: the summer period (covering July and 
August) and the fall period (covering September and October). Animal 
densities encountered in the Chukchi Sea during both of these time 
periods will further depend on the presence of ice. However, if ice is 
present close to the project area, drilling operations will not start 
or will be halted, so cetacean densities related to ice conditions are 
not included in COP's IHA application. Pinniped species in the Chukchi 
Sea do not show a distinct seasonal distribution during the period 
July-October (Aerts et al., 2011) and as such density estimates derived 
for seal species are used for both the summer and fall periods.
    Some sources from which densities were used include correction 
factors to account for perception and availability bias in the reported 
densities. Perception bias is associated with diminishing probability 
of sighting with increasing lateral distance from the trackline, where 
an animal is present at the surface but could be missed. Availability 
bias refers to the fact that the animal might be present but is not 
available at the surface. In cases where correction factors were not 
included in the reported densities, the best available correction 
factors were applied.
    To account for variability in marine mammal presence, COP derived 
maximum density estimates were in addition to average density 
estimates. Except where specifically noted, the maximum estimates have 
been calculated as double the average estimates. COP determined that 
this factor was large enough to allow for chance encounters with 
unexpected large groups of animals or for overall higher densities than 
expected. Table 8 in COP's IHA application indicates that the ``average 
estimate'' for humpback, fin, minke, and killer whales is either zero 
or one. Additionally, Table 8 in the application indicates that the 
``average estimate'' for harbor porpoise and beluga whales is low. 
Therefore, to account for the fact that these species listed as being 
potentially taken by harassment in this document may occur in COP'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.
    Estimated densities of marine mammals in the Chukchi Sea project 
area during the summer (July-August) and fall (September-October) 
periods are presented in Table 4 in COP's application and Table 1 here. 
Descriptions of the individual density estimates shown in the tables 
are presented next.

Cetacean Densities

    Eight cetacean species are known to occur in the northeastern 
Chukchi Sea. Of these, bowhead, beluga, gray, and killer whales and 
harbor porpoise are likely to be encountered in the proposed project 
area. Fin, humpback, and minke whales may occur but likely in lower 
numbers than the other cetacean species.
(1) Beluga Whales
    Summer densities of belugas in offshore waters of the Chukchi Sea 
are expected to be low, with higher densities at the ice-margin and in 
nearshore areas. Aerial surveys have recorded few belugas in the 
offshore Chukchi Sea during the summer months (Moore et al., 2000b). 
COMIDA aerial surveys flown in 2008, 2009, and 2010 reported a total of 
733 beluga sightings during >32,202 mi (51,824 km) of on-transect 
effort, resulting in 0.0141 beluga whales per km (Clarke et al., 2011). 
Belugas were seen every month except September, with most sightings in 
July.
    There was one sighting of nearly 300 belugas nearshore between 
Wainwright and Icy Cape in 2009, and several hundred belugas were 
sighted in Elson Lagoon, east of Pt. Barrow in 2010. Group size ranged 
from 1 to 480 individuals. Highest sighting rate per

[[Page 12573]]

depth zone was in shallow water (<= 115 ft [35 m] depth), which was 
likely due to the large groups described above. No beluga whales were 
sighted during the 2008-2010 vessel-based marine mammal CSESP surveys 
that covered the Devils Paw prospect and two other lease areas in the 
northeastern Chukchi Sea (Brueggeman et al., 2009b, 2010; Aerts et al., 
2011). Some beluga vocalizations were detected in October 2009 around 
Barrow and in the Burger lease area by acoustic recorders deployed as 
part of the CSESP program, but none in the Devils Paw prospect (Delarue 
et al., 2011). Also, no beluga sightings were reported during >11,185 
mi (18,000 km) of vessel-based effort in good visibility conditions 
during 2006-2008 industry operations in the northeastern Chukchi Sea 
(Haley et al., 2010).
    The COMIDA aerial survey summer and fall data (Clarke et al., 2011) 
were used to calculate expected average densities in the Devils Paw 
prospect. Because the reported densities (Whales Per Unit Effort) are 
not corrected for perception or availability bias, a f(0) value of 
2.841 and g(0) value of 0.58 from Harwood et al. (1996) were applied to 
arrive at estimated corrected densities, using the equation from 
Buckland et al. (2001). In the months July and August, two on-transect 
beluga sightings of five animals were observed in water depths of 118-
164 ft (36-50 m) along 7,447 mi (11,985 km) line transect. After 
applying the correction factors mentioned above, this resulted in a 
density of 0.0010 whales/km\2\ (Table 4 in COP's application and Table 
1 here). The three on-transect beluga sightings of six animals recorded 
in the period September-October along 6,236 mi (10,036 km) effort 
resulted in a corrected density of 0.0015 whales/km\2\.
    The absence of any beluga sightings during the 2008-2010 CSESP 
marine mammal research (Brueggeman et al., 2009b, 2010; Aerts et al., 
2011), the 2006-2008 industry programs (Haley et al., 2010), and the 
low number of acoustic detections in the vicinity of the project area 
(Delarue et al., 2011), are consistent with the relative low summer and 
fall densities in water depths of 118-164 ft (36-50 m) as calculated 
with the COMIDA aerial survey data.
(2) Bowhead Whales
    Most bowhead whales that will be observed in the northeastern 
Chukchi Sea are either migrating north to feeding grounds in the 
eastern Beaufort Sea during spring (prior to the start of COP's 
proposed activities), or migrating south to their wintering grounds in 
the Bering Sea during the fall. By July, most bowhead whales have 
passed Point Barrow, although some have been visually and acoustically 
detected during the entire summer in low numbers in the northeastern 
Chukchi Sea (Moore et al., 2010; Thomas et al., 2010; Quakenbush et 
al., 2010; Clarke and Ferguson, in prep.). Bowheads are more widely 
scattered in the northeastern Chukchi Sea during the fall migration but 
generally keep an offshore route. During aerial surveys in the COMIDA 
area from 1982-1991 and 2008-2010, a total of 88 on-effort sightings of 
121 bowhead whales were observed. Bowhead whales were seen in all 
months from June to October, with the greatest number of sightings 
occurring in October (Clarke et al., 2011; Clarke and Ferguson, in 
prep.). Similarly, bowhead whales were sighted in July-August during 
nearshore aerial surveys conducted in 2006-2008 in the northeastern 
Chukchi Sea but with increasing number of sightings in September and 
October (Thomas et al., 2010). Vessel-based CSESP marine mammal surveys 
conducted in Devils Paw prospect and two other lease areas in the 
northeastern Chukchi Sea recorded a total of 40 sightings of 59 animals 
during 2008-2010 with all but one sighting in October (Brueggeman et 
al., 2009, 2010; Aerts et al., 2011).
    The estimate of summer and fall bowhead whale density in the 
Chukchi Sea was calculated using the 2008-2010 COMIDA aerial survey 
data (Clarke and Ferguson, in prep.). No bowhead whales were sighted 
during the 7,447 mi (11,985 km) of survey effort in waters of 118-164 
ft (36-50 m) during July-August. However, for density estimates in this 
IHA, COP assumed there was one sighting of one bowhead. To improve the 
understanding of what factors significantly affect bowhead whale 
detections from aerial surveys, a distance detection function was 
estimated using 25 years of aerial line transect surveys in the Bering, 
Chukchi and Beaufort Seas (Givens et al., 2010). Because the correction 
factor from this study is lower than the estimates by Thomas et al. 
(2002), COP used the higher values to estimate densities for the 
purpose of this IHA. When applying a f(0) value of 2 and a g(0) value 
of 0.07 from Thomas et al. (2002), the summer density was estimated to 
be 0.0012 whales/km\2\ (Table 4 in COP's application and Table 1 here). 
Clarke and Ferguson (in prep.) reported 14 sightings of 15 individuals 
during 6,236 mi (10,036 km) of on transect aerial survey effort in 
September and October 2008-2010. Applying the same f(0) and g(0) values 
as for the summer density estimate, the bowhead density estimate for 
the fall is 0.0214 whales/km\2\ (Table 4 in COP's application and Table 
1 here). A total of 36 on-transect sightings of 55 bowheads were 
observed along 8,169 mi (13,146 km) transect effort during the vessel-
based CSESP marine mammal surveys in September and October. Applying 
the same correction factors as above resulted in a corrected bowhead 
density of 0.0598 whales/km\2\. This high density coincided with a peak 
in whale migration the first week of October, which was also apparent 
on the acoustic records (Delarue et al., 2011). Although none of these 
sightings were in the Devils Paw prospect, the maximum fall bowhead 
density estimate has been calculated as triple the average estimates, 
to cover for such migration peaks.
(3) Gray Whales
    Gray whale densities are expected to be highest in nearshore areas 
during the summer months with decreasing numbers in the fall. Moore et 
al. (2000b) reported a scattered distribution of gray whales generally 
limited to nearshore areas where most whales were observed in water 
less than 115 ft (35 m) deep. Nearshore aerial surveys along the 
Chukchi coast also reported substantial declines in the sighting rates 
of gray whales in the fall (Thomas et al., 2010). The average open-
water summer and fall densities presented in Table 4 in COP's 
application and Table 1 here were calculated from the 2008-2010 COMIDA 
aerial survey data (Clarke and Ferguson, in prep.). The summer data for 
water depths 118-164 ft (36-50 m) included 54 sightings of 73 
individuals during 7,447 mi (11,985 km) of on-transect effort. Applying 
the correction factors f(0) = 2.49 and g(0) = 0.95 (Forney and Barlow, 
1998 Table 1, based on aerial survey data) resulted in a summer density 
of 0.0080 whales/km\2\ (Table 4 in COP's application and Table 1 here). 
The number of gray whale sightings in the offshore study areas during 
the 2008-2010 CSESP marine mammal survey were limited in July and 
August; eight sightings of nine animals along 4,223 mi (6,796 km) on-
transect effort. Most of these animals were observed nearshore of 
Wainwright (Brueggeman et al., 2009, 2010; Aerts et al., 2011) and only 
two sightings of three animals were recorded in the Devils Paw 
Prospect. Densities from vessel based surveys in the Chukchi Sea during 
non-seismic periods and locations in July and August of 2006-2008 
(Haley et al., 2010) ranged from 0.0021 to 0.0080 whales/km\2\ with a 
maximum 95 percent CI of 0.0336.

[[Page 12574]]

    In the fall, gray whales may be dispersed more widely through the 
northern Chukchi Sea (Moore et al., 2000b; Clarke and Ferguson, in 
prep.), but overall densities are likely to be decreasing as the whales 
begin migrating south. The average fall density was calculated from 15 
sightings of 19 individuals during 6,236 mi (10,036 km) of on-transect 
effort in water 118-164 ft (36-50 m) deep during September and October 
(Clarke and Ferguson, in prep.). Applying the same f(0) and g(0) values 
as for the summer density, resulted in 0.0025 whales/km\2\ (Table 4 in 
COP's application and Table 1 here). During the CSESP survey in 
September and October, 25 gray whale sightings of 36 individuals were 
observed along 8,169 mi (13,146 km) of on-transect effort, resulting in 
an uncorrected density of 0.0027 whales/km\2\. Most of these whales 
were, however, observed nearshore of Wainwright (within 31 mi [50 km] 
from the coast) and none in the Devils Paw Prospect. Densities from 
vessel based surveys in the Chukchi Sea during non-seismic periods and 
locations in July and August of 2006-2008 (Haley et al., 2010) ranged 
from 0.0026 to 0.0042 whales/km\2\ with a maximum 95% CI of 0.0277.
(4) Harbor Porpoise
    Distribution and abundance data of harbor porpoise were very 
limited prior to 2006, and presence of the harbor porpoise was expected 
to be very low in the northeastern Chukchi Sea.
    Starting in 2006, several vessel-based marine mammal observer 
programs took place in the northeastern Chukchi Sea as part of seismic 
and shallow hazard survey monitoring and mitigation plans (Haley et 
al., 2010). During these surveys, 37 sightings of 61 harbor porpoises 
were reported. Three on-transect sightings of seven harbor porpoises 
were observed in the Devils Paw prospect in July and August along 4,223 
mi (6,796 km) of on-transect effort during the CSESP marine mammal 
surveys. No harbor porpoises were observed in the fall (Brueggeman et 
al., 2009, 2010; Aerts et al., 2011). COP used the 2008-2010 CSESP data 
to calculate densities for the purpose of this IHA. The uncorrected 
average density for the summer based on the three year CSESP data is 
0.0010 porpoises/km\2\ (Table 4 in COP's application and Table 1 here). 
As a comparison, summer density estimates from 2006-2008 marine mammal 
monitoring and mitigation programs during non-seismic periods ranged 
from 0.0008 to 0.0015 animals/km\2\ with a maximum 95 percent CI of 
0.0079 animals/km\2\ (Haley et al., 2010).
    Assuming that one sighting of one animal would have been observed 
along 8,169 mi (13,146 km) transect effort during the 2008-2010 CSESP 
surveys in the fall, the average uncorrected fall density is 0.0001 
porpoises/km\2\ (Table 4 in COP's application and Table 1 here). Harbor 
porpoise densities recorded during non-seismic periods in the fall 
months of 2006-2008 ranged from 0.0002 to 0.0011 animals/km\2\ with a 
maximum 95 percent CI of 0.0093 animals/km\2\. The maximum value of 
0.0011 animals/km\2\ from these surveys was used as the maximum fall 
density estimate for this IHA (Table 4 in COP's application and Table 1 
here).
(5) Other Cetaceans
    The remaining cetacean species that could be encountered in the 
Chukchi Sea during COP's planned activities include the humpback, fin, 
minke, and killer whales. The northeastern Chukchi Sea is at the 
northern edge of the known distribution range of most of these animals, 
although in recent years several sightings of some of these cetaceans 
were recorded in the area. During the 2008-2010 marine mammal aerial 
surveys in the COMIDA area, one humpback and one fin whale were 
observed, but none were observed in 1982-1991 in the same area (Clarke 
et al., 2011). Two sightings of four fin whales were recorded in 2008 
in the northeastern Chukchi Sea during 2006-2008 marine mammal 
monitoring programs from seismic and shallow hazard survey vessels 
(Haley et al., 2010). During the vessel-based 2008-2010 CSESP marine 
mammal surveys, two killer whale pods of 9 individuals were observed in 
the Devils Paw prospect and also one minke whale (Brueggeman et al., 
2009, 2010; Aerts et al., 2011). Although there is evidence of the 
occurrence of these animals in the Chukchi Sea, it is unlikely that 
more than a few individuals will be encountered during the proposed 
activities. The expected average densities of these species for the 
purpose of this IHA are therefore estimated at 0.0001 animal/km\2\. The 
maximum density estimates have been calculated as quadruple the average 
estimates to account for the increasing trend in number of observations 
during recent years (Table 4 in COP's application and Table 1 here).

Pinniped Densities

    Four species of pinnipeds under NMFS jurisdiction occur in the 
Chukchi Sea during COP's proposed activities of which three are most 
likely to be encountered: ringed seal, bearded seal, and spotted seal. 
Each of these species is associated with presence of ice and the 
nearshore area. For ringed and bearded seals the ice margin is 
considered preferred habitat during most seasons (as compared to the 
nearshore areas). Spotted seals are considered to be predominantly a 
coastal species except in the spring when they may be found in the 
southern margin of the retreating sea ice. Satellite tagging studies 
have shown that spotted seals sometimes undertake long excursions into 
offshore waters during summer (Lowry et al., 1994, 1998). Ribbon seals 
were observed during the vessel-based CSESP surveys in 2008, when ice 
was present in the area (Brueggeman et al., 2009), and they were also 
reported in very small numbers within the northeastern Chukchi Sea by 
observers on industry vessels (Haley et al., 2010).

   Table 1--Estimated Densities of Cetaceans and Pinnipeds in the Northeastern Chukchi Sea Expected During the
            Proposed Drilling Operations in the Devils Paw Prospect During the 2014 Open-Water Season
----------------------------------------------------------------------------------------------------------------
                                                                     July/August            September/October
              Density in numbers per square km               ---------------------------------------------------
                                                                  Avg          Max          Avg          Max
----------------------------------------------------------------------------------------------------------------
Beluga whale................................................       0.0010       0.0020       0.0015       0.0030
Killer whale................................................       0.0001       0.0004       0.0001       0.0004
Harbor porpoise.............................................       0.0010       0.0020       0.0001       0.0011
Bowhead whale...............................................       0.0012       0.0024       0.0214       0.0641
Gray whale..................................................       0.0080       0.0160       0.0025       0.0050
Humpback whale..............................................       0.0001       0.0004       0.0001       0.0004
Fin whale...................................................       0.0001       0.0004       0.0001       0.0004
Minke whale.................................................       0.0001       0.0004       0.0001       0.0004

[[Page 12575]]

 
Bearded seal................................................       0.0135       0.0248       0.0135       0.0248
Ringed seal.................................................       0.0516       0.1256       0.0516       0.1256
Spotted seal................................................       0.0244       0.0355       0.0244       0.0355
Ribbon seal.................................................       0.0020       0.0060       0.0020       0.0060
----------------------------------------------------------------------------------------------------------------
Note: Species listed under the U.S. ESA as Endangered are in italics.


Table 2--Modeled Distances to Received Sound Pressure Level Criteria Used by NMFS for the Relevant Sound Sources
       of the Proposed Project and the Areas Used to Estimate the Number of Potential Takes by Harassment
----------------------------------------------------------------------------------------------------------------
                                                                   Received SPL        Modeled      Area (km\2\)
                          Sound source                           (dB re 1 [mu]Pa)  distance  (km)      used *
----------------------------------------------------------------------------------------------------------------
Continuous sound source
    Drilling...................................................            160 db           <0.01  .............
                                                                           120 dB            0.21  .............
    Support vessel in dynamic positioning......................            160 dB            0.71  .............
                                                                           120 dB            7.90          201
    Ice management.............................................            160 dB            0.71  .............
                                                                           120 dB            7.90          201
Pulsed sound source
    VSP airguns................................................            190 dB            0.16  .............
                                                                           180 dB            0.92  .............
                                                                           160 dB            4.90           78.5
                                                                           120 dB        ** 71.0   .............
----------------------------------------------------------------------------------------------------------------
* Areas ensonified with continuous sound levels of 120 dB and pulsed sound levels of 160 dB displayed in this
  column were used to estimate the number of marine mammals potentially exposed to these levels (see Section
  6.2.1).--means not applicable
** Contours of 120 dB re 1 [mu]Pa for airgun sounds extended beyond the modeling area and as such the distance
  shown is based on extrapolation of the data and therefore uncertain.

    Aerial survey data from Bengston et al. (2005) were initially used 
for bearded and ringed seal densities. However, because these surveys 
were conducted in the spring during the seal basking season, the 
reported densities might not be applicable for the open-water summer 
and fall period. Therefore, the 2008-2010 CSESP vessel-based marine 
mammal survey data were used to calculate seal densities. The densities 
for spotted and ribbon seals were also based on the 2008-2010 CSESP 
marine mammal survey data (Aerts et al., 2011). Perception bias was 
accounted for in the CSESP densities, but the number of animals missed 
because they were not available for detection was not taken into 
account. The assumption was made that all animals available at distance 
zero from the observer, this is on the transect line, were detected 
[g(0)=1]. The amount of animals missed due to perception bias was 
calculated using distance sampling methodology (Buckland et al., 2001; 
Buckland et al., 2004). Program Distance 6.1 release 1 (Thomas et al., 
2010) was used to analyze effects of distance and environmental factors 
(e.g., sea state, visibility) on the probability of detecting marine 
mammal species.
    During the CSESP studies, a relatively large percentage of seal 
sightings were classified as ringed/spotted seals (meaning it was 
either a spotted or a ringed seal) and unidentified seals (meaning it 
could be any of the four seal species observed). These sightings had to 
be taken into account to avoid an underestimation of densities for each 
separate seal species. The ratio of ringed versus spotted seal 
densities for each study area and year was used to estimate the 
proportional density of each of these two species from the combined 
ringed/spotted seal densities. This estimated proportional density was 
then added to the observed densities. The same method was used to 
proportionally divide the unidentified seal sightings over spotted, 
ringed, and bearded seal sightings. Applying the ratio of identified 
seal species to the unidentified individuals assumes that the 
disability of identification is similar for each species. Considering 
the conditions of these occurrences (animals either far away or only at 
the surface for a very brief moment), this is likely to be true. The 
above described adjustment increased densities for each species but did 
not change observed trends in occurrence.
(1) Bearded Seals
    Densities from 1999-2000 spring surveys in the offshore pack ice 
zone (zone 12P) of the northern Chukchi Sea (Bengtson et al., 2005) 
were initially consulted for bearded seal average and maximum summer 
densities. A correction factor for bearded seal availability bias, 
based on haul out and diving patterns was not available and therefore 
not included in the reported densities. Average density of bearded 
seals on the offshore pack ice in zone 12P was 0.018 seals/km\2\, with 
a maximum density of 0.027 seals/km\2\ (Bengston et al., 2005). During 
the 2008-2010 CSESP marine mammal survey, bearded seal density in the 
Devils Paw prospect from July-October was 0.025 seals/km\2\ in 2008, 
0.004 seals/km\2\ in 2009, and 0.011 seals/km\2\ in 2010 (Aerts et al., 
2011). The average density over these three years was 0.014 seals/
km\2\, and the maximum density was 0.025 seals/km\2\. The average

[[Page 12576]]

density of the CSESP surveys is about 30% lower than reported by 
Bengston et al. (2005) and the maximum CSESP densities about 10% lower. 
It was decided to use the CSESP average and maximum densities data as 
these were gathered in the area of operation during the same season as 
the proposed operations (Table 4 in COP's application and Table 1 
here).
(2) Ringed Seals
    Ringed seal average and maximum summer densities were also 
calculated from the 1999-2000 spring aerial survey data in the offshore 
pack ice zone (zone 12P) of the northern Chukchi Sea (Bengtson et al., 
2005). Ringed seal availability bias, g(0), based on haul out and 
diving patterns was used in the reported densities. Average density of 
ringed seals on the offshore pack ice in zone 12P was 0.052 seals/km\2\ 
and the maximum density 0.81 seals/km\2\ (Bengston et al., 2005). 
During the 2008-2010 CSESP marine mammal survey, ringed seal density in 
the Devils Paw prospect from July-October was 0.126 seals/km\2\ in 
2008, 0.018 seals/km\2\ in 2009, and 0.012 seals/km\2\ in 2010 (Aerts 
et al., 2011). The average density over these 3 years was 0.052 seals/
km\2\ and the maximum density 0.126 seals/km\2\. The average density of 
the CSESP surveys is very similar to that reported by Bengston et al. 
(2005), but the maximum CSESP density was about 6 times lower. As with 
the bearded seal density, it was decided to use the CSESP average and 
maximum densities data as these were gathered in the area of operation 
during the same season as the proposed operations (Table 4 in COP's 
application and Table 1 here). The maximum density was obtained in a 
year when ice was present in the area.
(3) Spotted Seals
    Little information is available on spotted seal densities in 
offshore areas of the Chukchi Sea. Spotted seal densities were 
calculated based on the data collected during the CSESP marine mammal 
survey (Aerts et al., 2011). Spotted seal density in the Devils Paw 
prospect from July-October was 0.036 seals/km\2\ in 2008, 0.019 seals/
km\2\ in 2009, and 0.018 seals/km\2\ in 2010 (Aerts et al., 2011). The 
average density over these three years was 0.024 seals/km\2\ and the 
maximum density 0.036 seals/km\2\ (Table 4 in COP's application and 
Table 1 here).
(4) Ribbon Seals
    Four ribbon seal sightings of four individuals were recorded in the 
Devils Paw prospect during the CSESP survey from July-October 2008 
(Brueggeman et al., 2009). No ribbon seals were sighted in 2009 and 
2010 (Brueggeman et al., 2010; Aerts et al., 2011). Density calculated 
from this limited number of sightings in 2008 was 0.006 seals/km\2\. 
The average and maximum densities were 0.002 seals/km\2\ and 0.006 
seals/km\2\, respectively. Note that the 2008 density calculated for 
this IHA had, as expected, an extremely large coefficient of variation 
due to the limited number of sightings.

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

    An acoustic propagation model (i.e. JASCO's Marine Operations Noise 
Model) was used to estimate distances to received rms SPLs of 190, 180, 
160, and 120 dB re 1[mu]Pa from the drill rig, support vessel on DP 
alongside the drill rig, and from the VSP airguns. The distances to 
reach received sound levels of 120 dB re 1 [mu]Pa (for continuous sound 
sources, such as drilling activities, support vessels, and ice 
management) and 160 dB re 1 [mu]Pa (for pulsed sound sources, such as 
the VSP airguns) are used to calculate the potential numbers of marine 
mammals potentially harassed by the proposed activities. The distances 
to received levels of 180 dB and 190 dB re 1 [mu]Pa (rms) will be used 
to establish exclusion zones for mitigation purposes (see the 
``Proposed Mitigation'' section earlier in this document). Three 
scenarios were considered for modeling:
    1. Jack-up rig performing drilling operations (without support 
vessels);
    2. Jack-up rig performing drilling operations with the support 
vessel alongside in DP mode, i.e., maintaining position using 
thrusters; and
    3. 760 in\3\ ITAGA airgun array operating at the drill site as 
representative for VSP data acquisition runs.
    The results of these model runs are shown in the report ``Acoustic 
Modeling of Underwater Noise from Drilling Operations at the Devils Paw 
prospect in the Chukchi Sea'' (Attachment A of COP's application) and 
are summarized in Table 5 of COP's application and Table 2 here.
    The ice management vessel is part of an ice alerts system and 
available to assist operations by conducting ice reconnaissance trips 
and protecting the rig from potential ice hazards if necessary. COP 
does not expect physical management of ice to be necessary during the 
open-water season and does not intend to engage in icebreaking. If ice 
floes are determined to require a managed response to protect the drill 
rig, the use of fire monitors (water cannons) or the vessel itself to 
modify ice floe trajectory is the most likely response. As summarized 
earlier in this document, an SPL of about 193 dB re 1[mu]Pa at 1 m was 
estimated to be a reasonable peak value for ice management vessels 
during different sea ice conditions and modes of propulsion level (Roth 
and Schmidt, 2010). Sound levels generated during physical management 
of ice are not expected to be as intense as during icebreaking 
activities described in most literature. Instead of actually breaking 
ice, the vessel will redirect and reposition the ice with slow 
movements, pushing it away from the direction of the drill rig at slow 
speeds so that the ice floe does not form any hazard to the drilling 
operations. At these slow speeds the vessel uses low power, with slow 
propeller rotation speed, thereby reducing noise generation from 
propeller rotation effects in the water. For the purpose of estimating 
the number of marine mammals potentially eliciting behavioral 
responses, COP assumed that the distance to received sound pressure 
levels of 120 dB re 1[mu]Pa from physical ice management is similar to 
that modeled for the support vessel on DP, i.e. 4.9 mi (7.9 km). This 
is considered to be an overestimation, since source levels from the 
proposed physical management of ice are expected to be much lower than 
the 204 dB re 1[mu]Pa used for the support vessel and also lower than 
the 193 dB re 1[mu]Pa reported for icebreaking activities.

Potential Number of Takes by Harassment

    Although a marine mammal may be exposed to drilling, DP, or ice 
management sounds =120 dB (rms) or airgun sounds 
=160 dB (rms), 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.
    The 160 dB criterion is applied to pulsed sounds generated by 
airguns during the two or three VSP data acquisition runs that will be 
of short duration (with a total of about 2 hrs of airgun activity for 
two to three runs per well, not including time required for ramp up). 
The 120 dB criterion is applied to sounds from the drill rig for 
situations where the support vessel is located alongside the drill rig 
in DP mode, i.e., the scenario with highest sound production. This 
situation will occur about four times a week for a

[[Page 12577]]

maximum of 6 hrs per occurrence, i.e., about 318 hrs of DP based on 53 
trips over the entire drilling season for the ware vessel and 4.5 times 
a week, i.e., about 378 hrs for the OSV. The 120 dB criterion is also 
applied to any physical management of ice that might occur. For 
analytical purposes, physical ice management was conservatively 
estimated at up to 72 hrs, only in July and August. The area ensonified 
with continuous sound levels of 120 dB re1 [mu]Pa (rms) during drilling 
activity only is so small (<0.2 km\2\) that it does not appreciably add 
to the total estimated number of marine mammal exposures and is 
therefore not included in the calculations.
    The area around the drill rig ensonified with pulsed sound levels 
>=160 dB re1 [mu]Pa (rms) during VSP runs is estimated at 30 mi\2\ 
(78.5 km\2\; radius of 3.1 mi or 5 km), and 78 mi\2\ (201 km\2\; radius 
of 5 mi or 8 km) for continuous sound levels of >=120 dB re1 [mu]Pa 
(rms) during times when the support vessel is attending the rig and 
during physical management of ice (Table 5 in COP's application and 
Table 2 here).
    The potential number of each species that might be exposed to 
received continuous SPLs of >=120 dB re 1 [mu]Pa (rms) and pulsed SPLs 
of >=160 dB re 1 [mu]Pa (rms) was calculated by multiplying:
     The expected (seasonal) species density as provided in 
Table 4 of COP's application and Table 1 here;
     the anticipated area to be ensonified by the 120 dB re 1 
[mu]Pa (rms) SPL (support vessel in DP mode and ice management 
activity) and 160 dB re 1 [mu]Pa (rms) SPL (VSP airgun operations); and
     the estimated total duration of each of the three 
activities within each season expressed in days (24 hrs).
    To derive at an estimated total duration for each of the three 
activities for each season (summer and fall) the following assumptions 
were made:
     The total duration during which the support vessel will be 
in DP mode is 318 + 378 = 696 hrs. This is the equivalent of 29 days 
over the entire season, with 14.5 days in July/August and 14.5 days in 
September/October.
     Physical management of ice was assumed to take place only 
in the early season, and, for analytical purpose, estimated at a total 
of 72 hrs. No physical management of ice is assumed in September or 
October. If sea ice becomes an issue in October, drilling activities 
will likely be halted and the drill rig prepared for demobilization.
     The ensonified area of 120 dB re 1[mu]Pa for continuous 
sounds of the support vessel in DP mode and active ice management are 
assumed to be similar. To be conservative, COP assumed that the 
ensonified areas of these two activities will not overlap. The duration 
of both of these activities combined, used to calculate marine mammal 
exposures to 120 dB re 1 [mu]Pa (rms), is therefore17.5 days (=14.5 + 
3) for July/August and 14.5 days for September/October.
     The total duration of the two or three VSP data 
acquisition runs per well is estimated to be 24 hrs, during which the 
airguns will be operating a total of about 2 hrs. Assuming COP will do 
additional VSP data acquisition runs for a second well, the total time 
of operating airgun activity is estimated about 4 hrs. To be 
conservative, COP included airgun time for ramp ups. Therefore, COP 
used 12 hrs (0.5 day) in July/August and 12 hrs (0.5 day) in September/
October for the calculations of potential exposures.
    Table 6 in COP's application summarizes the number of marine 
mammals potentially exposed to continuous SPLs of 120 dB re 1 [mu]Pa 
from support vessels on DP and physical ice management. Table 7 in 
COP's application summarizes the estimated number of marine mammals 
potentially exposed to pulsed SPLs of 160 dB re 1 [mu]Pa during the VSP 
runs. The total number of potential marine mammal exposures from all 
three activities combined is provided in Table 8 of COP's application. 
Additional information is contained in Section 6 of COP's IHA 
application.
    NMFS is proposing to authorize the maximum take estimates provided 
in Table 8 of COP's application, except for the species noted earlier 
in this section to account for typical group size of those species. 
Table 3 in this document outlines the abundance, proposed take, and 
percentage of each stock or population for the 12 species that may be 
exposed to sounds =120 dB from the drill rig with support 
vessels in DP mode and ice management activities and to sounds 
=160 dB from VSP activities in COP's proposed Chukchi Sea 
drilling area. Less than 1.3% of each species or stock would 
potentially be exposed to sounds above the Level B harassment 
thresholds. The take estimates presented here do not take any of the 
mitigation measures presented earlier in this document into 
consideration. 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.

 Table 3--Population Abundance Estimates, Total Proposed Level B Take Estimates (When Combining Takes From Drill
  Rig Operations, Ice Management, DP, and VSP Surveys), and Percentage of Stock or Population That may be Taken
         for the Potentially Affected Species That may Occur in COP's Proposed Chukchi Sea Drilling Area
----------------------------------------------------------------------------------------------------------------
                                                                                                   Percentage of
                           Species                               Abundance \1\    Total proposed     stock or
                                                                                       take         population
----------------------------------------------------------------------------------------------------------------
Beluga Whale.................................................              3,710              16             0.4
Killer Whale.................................................                656              20               3
Harbor Porpoise..............................................             48,215              10            0.02
Bowhead Whale................................................         \2\ 15,750             200             1.3
Fin Whale....................................................              5,700               5            0.09
Gray Whale...................................................             18,017              72             0.4
Humpback Whale...............................................              2,845               5             0.2
Minke Whale..................................................          810-1,233               5         0.4-0.6
Bearded Seal.................................................        \3\ 155,000             161             0.1
Ribbon Seal..................................................             49,000              15            0.03
Ringed Seal..................................................    208,000-252,000             818         0.3-0.4
Spotted Seal.................................................            141,479             231             0.2
----------------------------------------------------------------------------------------------------------------
\1\ Unless stated otherwise, abundance estimates are taken from Allen and Angliss (2012).

[[Page 12578]]

 
\2\ Estimate from George et al. (2004) with an annual growth rate of 3.4%.
\3\ Beringia Distinct Population Segment (NMFS, 2010).

Negligible Impact and Small Numbers Analysis and Preliminary 
Determination

    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 
COP's proposed Chukchi Sea 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. COP 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 COP'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 across the Chukchi Sea 
towards their wintering grounds.
    Bowhead and beluga whales are less likely to occur in the proposed 
project area in July and August, as they are found mostly in the 
Canadian Beaufort Sea at this time. The animals are more likely to 
occur later in the season (mid-September through October), as they head 
west towards Russia or south towards the Bering Sea. Additionally, 
while bowhead whale tagging studies revealed that animals occurred in 
the Lease Sale 193 area, a higher percentage of animals were found 
outside of the Lease Sale 193 area in the fall (Quakenbush et al., 
2010). Bowhead whales are not known to feed in areas near COP's leases 
in the Chukchi Sea. The closest primary feeding ground is near Point 
Barrow, which is more than 200 mi (322 km) east of COP's Devils Paw 
prospect. Therefore, if bowhead whales stop to feed near Point Barrow 
during COP's proposed operations, the animals would not be exposed to 
continuous sounds from the drill rig or support operations above 120 dB 
or to impulsive sounds from the airguns above 160 dB, as those sound 
levels only propagate 689 ft (210 m), 4.9 mi (7.9 km), and 3 mi (4.9 
km), respectively. Additionally, the 120-dB radius for the airgun array 
has been modeled to propagate 44 mi (71 km) from the source. Therefore, 
sounds from the operations would not reach the feeding grounds near 
Point Barrow. Gray whales occur in the northeastern Chukchi Sea during 
the summer and early fall to feed. However, the primary feeding grounds 
lies outside of the 120-dB and 160-dB ensonified areas from COP's 
activities. While some individuals may swim through the area of active 
drilling, it is not anticipated to interfere with their feeding in the 
Chukchi Sea. Other cetacean species are much rarer in the proposed 
project area. The exposure of cetaceans to sounds produced by 
exploratory drilling operations (i.e., drill rig, DP, ice management, 
and airgun operations) is not expected to result in more than Level B 
harassment.
    Few seals are expected to occur in the proposed project area, as 
several of the species prefer more nearshore waters. Additionally, 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. COP's proposed 
activities would occur at a time of year when the ice seal species 
found in the region are not molting, breeding, or pupping. Therefore, 
these important life functions would not be impacted by COP's proposed 
activities. The exposure of pinnipeds to sounds produced by COP's 
proposed exploratory drilling operations in the Chukchi Sea is not 
expected to result in more than Level B harassment of the affected 
species or stock.
    Of the 12 marine mammal species likely to occur in the proposed 
drilling area, three are listed as endangered under the ESA--the 
bowhead, humpback, and fin whales--and two are listed as threatened--
ringed and bearded seals. All five species are 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, 2012), 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). An annual increase of 
4.8% was estimated for the period 1987-2003 for North Pacific fin 
whales. While this estimate is consistent with growth estimates for 
other large whale populations, it should be used with caution due to 
uncertainties in the initial population estimate and about population 
stock structure in the area (Allen and Angliss, 2012). Zeribini et al. 
(2006, cited in Allen and Angliss, 2012) noted an increase of 6.6% for 
the Central North Pacific stock of humpback whales in Alaska waters. 
There are currently no reliable data on trends of the ringed and 
bearded seal stocks in Alaska. 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. The ribbon seal is a 
``species of concern.'' None of the other species that may occur in the 
project area are listed as threatened or endangered under the ESA or 
designated as depleted under the MMPA. There is currently no 
established critical habitat in the proposed project area for any of 
these 12 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, the impacts 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.
    The estimated takes proposed to be authorized represent less than 
1.3% of the affected population or stock for all species. These 
estimates represent the percentage of each species or stock that could 
be taken by Level B behavioral

[[Page 12579]]

harassment if each animal is taken only once. The estimated take 
numbers are likely somewhat of an overestimate. First, COP did not 
account for potential overlap of some of the sound sources if they are 
operating simultaneously. This leads to an overestimation of ensonified 
area. 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.
    Based on the analysis contained herein of the likely effects of the 
specified activity on marine mammals and their habitat, and taking into 
consideration the implementation of the proposed mitigation and 
monitoring measures, NMFS preliminarily finds that the proposed 
exploration drilling program will result in the incidental take of 
small numbers of marine mammals, by Level B harassment only, and that 
the total taking from the drilling program will have a negligible 
impact on the affected species or stocks.

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 Chukchi Sea that have the 
potential to be impacted by COP's offshore drilling program include 
Point Hope, Point Lay, Wainwright, Barrow, and possibly Kotzebue and 
Kivalina (however, these two communities are much farther to the south 
of the proposed project area). Point Lay, Wainwright, Point Hope, 
Barrow, and Kivalina are approximately 90 mi (145 km), 120 mi (193 km), 
175 mi (282 km), 200 mi (322 km), and 225 mi (362 km) from the Devils 
Paw prospect, respectively. The communities of Gambell and Savoonga on 
St. Lawrence Island also have the potential to be impacted if vessels 
pass close by the island during times of active hunting.
(1) Bowhead Whales
    Bowhead whale hunting is a key activity in the subsistence 
economies of northwest Arctic communities. The whale harvests have a 
great influence on social relations by strengthening the sense of 
Inupiat culture and heritage in addition to reinforcing family and 
community ties.
    An overall quota system for the hunting of bowhead whales was 
established by the International Whaling Commission (IWC) in 1977. The 
quota is now regulated through an agreement between NMFS and the Alaska 
Eskimo Whaling Commission (AEWC). The AEWC allots the number of bowhead 
whales that each whaling community may harvest annually (USDOI/BLM, 
2005). The annual take of bowhead whales has varied due to (a) changes 
in the allowable quota level and (b) year-to-year variability in ice 
and weather conditions, which strongly influence the success of the 
hunt.
    Bowhead whales migrate around northern Alaska twice each year, 
during the spring and autumn, and are hunted in both seasons. Bowhead 
whales are hunted from Barrow during the spring and the fall migration. 
The spring hunt along Chukchi villages and at Barrow occurs after leads 
open due to the deterioration of pack ice; the spring hunt typically 
occurs from early April until the first week of June. From 1984-2009, 
bowhead harvests by the villages of Wainwright, Point Hope, and Point 
Lay occurred only between April 14 and June 24 and only between April 
23 and June 15 in Barrow (George and Tarpley, 1986; George et al., 
1987, 1988, 1990, 1992, 1995, 1998, 1999, 2000; Philo et al., 1994; 
Suydam et al., 1995b, 1996, 1997, 2001b, 2002, 2003, 2004, 2005b, 2006, 
2007, 2008, 2009, 2010). Point Lay landed its first whale in more than 
70 years during the spring hunt in 2009 and another whale during the 
2011 spring hunt. COP will not mobilize and move into the Chukchi Sea 
prior to July 1.
    The fall migration of bowhead whales that summer in the eastern 
Beaufort Sea typically begins in late August or September. Fall 
migration into Alaskan waters is primarily during September and 
October. In the fall, subsistence hunters use aluminum or fiberglass 
boats with outboards. Hunters prefer to take bowheads close to shore to 
avoid a long tow during which the meat can spoil, but Braund and 
Moorehead (1995) report that crews may (rarely) pursue whales as far as 
50 mi (80 km). The autumn bowhead hunt usually begins in Barrow in mid-
September and mainly occurs in the waters east and northeast of Point 
Barrow. Fall bowhead whaling has not typically occurred in the villages 
of Wainwright, Point Hope, and Point Lay in recent years. However, a 
Wainwright whaling crew harvested the first fall bowhead whale in 90 
years or more on October 8, 2010, and again landed a whale in October 
2011. Because of changing ice conditions, there is the potential for 
these villages to resume a fall bowhead harvest.
    Barrow participates in a fall hunt each year. From 1984-2009, 
Barrow whalers harvested bowhead whales between August 31 and October 
29. While this time period overlaps with that of COP's proposed 
operations, the drill sites are located more than 200 mi (322 km) west 
of Barrow, so the whales would reach the Barrow hunting grounds before 
entering the sound field of COP's operations. COP will be flying 
helicopters out to the drillship for resupply missions. In the past 35 
years, however, Barrow whaling crews have harvested almost all whales 
in the Beaufort Sea to the east of Point Barrow (Suydam et al., 2008), 
indicating that relatively little fall hunting occurs to the west where 
the flight corridor is located. COP intends to base its flights out of 
Wainwright.
(2) Beluga Whales
    Beluga whales are available to subsistence hunters along the coast 
of Alaska in the spring when pack-ice conditions deteriorate and leads 
open up. Belugas may remain in coastal areas or lagoons through June 
and sometimes into July and August. The community of Point Lay is 
heavily dependent on the hunting of belugas in Kasegaluk Lagoon for 
subsistence meat. From 1983-1992 the average annual harvest was 
approximately 40 whales (Fuller and George, 1997). Point Hope residents 
hunt beluga primarily in the lead system during the spring (late March 
to early June) bowhead hunt but also in open-

[[Page 12580]]

water along the coastline in July and August. Belugas are harvested in 
coastal waters near these villages, generally within a few miles from 
shore.
    In Wainwright and Barrow, hunters usually wait until after the 
spring bowhead whale hunt is finished before turning their attention to 
hunting belugas. The average annual harvest of beluga whales taken by 
Barrow for 1962-1982 was five (MMS, 1996). The Alaska Beluga Whale 
Committee (ABWC) recorded that 23 beluga whales had been harvested by 
Barrow hunters from 1987 to 2002, ranging from 0 in 1987, 1988 and 1995 
to the high of 8 in 1997 (Fuller and George, 1997; ABWC, 2002 cited in 
USDOI/BLM, 2005). Barrow residents typically hunt for belugas between 
Point Barrow and Skull Cliffs in the Chukchi Sea (primarily April-June) 
and later in the summer (July-August) on both sides of the barrier 
island in Elson Lagoon/Beaufort Sea (MMS, 2008). Harvest rates indicate 
that the hunts are not frequent. Wainwright residents hunt beluga in 
April-June in the spring lead system, but this hunt typically occurs 
only if there are no bowheads in the area. Communal hunts for beluga 
are conducted along the coastal lagoon system later in July-August.
    COP's proposed exploration drilling activities take place well 
offshore, far away from areas that are used for beluga hunting by the 
Chukchi Sea communities. For vessel movements in nearshore areas, such 
as the alternate drill rig staging area or presence of oil spill 
response vessels, COP will consult with the communities on measures to 
mitigate potential impacts on subsistence hunts.
(3) Ringed Seals
    Ringed seals are hunted mainly in the Chukchi Sea from late March 
through July; however, they can be hunted year-round. In winter, leads 
and cracks in the ice off points of land and along the barrier islands 
are used for hunting ringed seals. The average annual ringed seal 
harvest was 49 seals in Point Lay, 86 in Wainwright, and 394 in Barrow 
(Braund et al., 1993; USDOI/BLM, 2003, 2005). Although ringed seals are 
available year-round, the planned activities will not occur during the 
primary period when these seals are typically harvested (March-July). 
Also, the activities will be largely in offshore waters where they will 
not influence ringed seals in the nearshore areas where they are 
hunted.
(4) Spotted Seals
    Most subsistence harvest of the spotted seal is conducted by the 
communities of Wainwright and Point Lay during the fall (September and 
October), when spotted seals migrate back to their wintering habitats 
in the Bering Sea (USDOI/BLM, 2003). Available maps of recent and past 
subsistence use areas for spotted seals indicate harvest of this 
species within 30-40 mi (48-64 km) of the coastline. Spotted seals are 
also occasionally hunted in the area off Point Barrow and along the 
barrier islands of Elson Lagoon to the east (USDOI/BLM, 2005). The 
planned activities will remain offshore of the coastal harvest area of 
these seals and should not conflict with harvest activities.
(5) Bearded Seals
    Bearded seals, although generally not favored for their meat, are 
important to subsistence activities in Barrow and Wainwright because of 
their skins. Six to nine bearded seal hides are used by whalers to 
cover each of the skin-covered boats traditionally used for spring 
whaling. Because of their valuable hides and large size, bearded seals 
are specifically sought. While bearded seals can be hunted year-round 
in the Chukchi Sea, they are primarily harvested in spring during 
breakup of the ice (Bacon et al., 2009). The animals inhabit the 
environment around the ice floes in the drifting nearshore ice pack, so 
hunting usually occurs from boats in the drift ice. Most bearded seals 
are harvested in coastal areas inshore of the proposed exploration 
drilling area, so no conflicts with the harvest of bearded seals are 
expected.

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 COP'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 
activity, such as tail-slapping, which translate to danger for nearby 
subsistence harvesters.

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. COP has developed a Draft POC for its 
2014 Chukchi Sea, Alaska, exploration drilling program to minimize any 
adverse impacts on the availability of marine mammals for subsistence 
uses. A copy of the POC was provided to NMFS with the IHA application 
(see ADDRESSES for availability). COP began conducting meetings with 
potentially affected communities in 2008. Exhibit 1 of COP's POC 
contains a list of all meetings that have taken place through November 
2012. Communities contacted include: Barrow, Kivalina, Kotzebue, Point 
Hope, Point Lay, and Wainwright. COP also presented this program at the 
2012 Open Water Meeting in Anchorage, Alaska, and plans to present at 
the 2013 Open Water Meeting, scheduled for March 5-7, 2013, in 
Anchorage, Alaska.
    COP intends to meet with the North Slope Borough, Northwest Arctic 
Borough, and Alaska Native marine mammal commissions before and after 
operations. COP will also communicate throughout operations as needed.
    In order to reduce impacts on subsistence hunts, COP intends to 
implement a Communication Plan. COP will establish a central 
communication station (Com-Station) located at Wainwright and 
communication outposts in Point Hope, Poing Lay, and Barrow. The 
Wainwright Com-Station will coordinate communication between the 
drilling rig, marine vessels, aircraft, and the communication outposts 
in each community as well as the

[[Page 12581]]

subsistence hunters in Wainwright. Personnel on the drilling rig or ice 
management vessel will provide information to the Com-Center about the 
timing and location of planned vessel activity. The communication 
outposts will provide information to the Com-Station about the timing 
and location of planned hunts. The Com-Station will relay information 
and facilitate communication so that vessel activities can be modified 
as necessary to prevent avoidable conflicts with subsistence hunting. 
Communication outposts may also be established and manned in other 
villages, such as Kivalina and Kotzebue, if subsistence activities 
associated with those villages are occurring near the exploration 
operations. A communication representative may also be present in Wales 
and Savoonga during mobilization and demobilization activities if 
subsistence activities are occurring.
    The Com-Station and outposts will be staffed by Inupiat 
communicators, if available. The duty of the Com-Station operator will 
be to stay in communication with outposts and with hunters regarding 
their subsistence hunting activities, and to relay information about 
subsistence hunting locations and activities to the drilling rig and 
marine vessels. The Com-Station operator will also provide the location 
of the drilling rig and marine vessels to the subsistence hunters and 
outposts.
    The drill rig, ice management vessel, and monitoring vessel will 
carry on-board an Inupiat Communicator, who will also serve as a PSO, 
during the operating season. If a vessel that is part of the drilling 
program is in the vicinity of a hunting area and the hunters have 
launched their boats, the Inupiat Communicator's primary duty will be 
to stay in communication with the hunters and relay information to the 
vessel captain about hunting location, activities, timing, and overall 
plans. At all other times, the Inupiat Communicator will be serving as 
a PSO and will be responsible for monitoring for bowhead whales and 
other marine mammals.
    COP will plan vessel routes to minimize potential conflict with 
marine mammals and subsistence activities related to marine mammals. 
Vessels will avoid areas of active hunting through communication with 
the established Com-Station by the Inupiat Communicator stationed on 
the rig. Moreover, many of the mitigation measures described earlier in 
this document (see the ``Proposed Mitigation'' section) will also help 
reduce impacts to subsistence hunts and subsistence uses of marine 
mammals. These include vessel operating measures when in the vicinity 
of marine mammals and helicopter flight altitude restrictions. 
Additionally, COP will not enter the Chukchi Sea prior to July 1 and 
will begin demobilization by October 31 so as to transit out of the 
Bering Strait no later than November 15.

Unmitigable Adverse Impact Analysis and Preliminary Determination

    COP's drill sites are located more than 70 mi (113 km) from shore, 
and some of the activities will not begin until after the close of 
spring hunts. Seal hunts typically do not co-occur with COP's proposed 
activities and those that do occur close to shore. COP will utilize 
Com-Stations to avoid conflicts with active hunts. After the close of 
the July beluga whale hunts in the Chukchi Sea villages, very little 
whaling occurs in Wainwright, Point Hope, and Point Lay. Although the 
fall bowhead whale hunt in Barrow will occur while COP is still 
operating (mid- to late September to October), Barrow is located 200 mi 
(322 km) east of the proposed drill sites. Based on these factors, 
COP's Chukchi Sea survey is not expected to interfere with the fall 
bowhead harvest in Barrow. In recent years, bowhead whales have 
occasionally been taken in the fall by coastal villages along the 
Chukchi coast, but the total number of these animals has been small. 
Wainwright landed its first fall whale in more than 90 years in October 
2010 and again landed a whale in October 2011. Hunters from the 
northwest Arctic villages prefer to harvest whales within 50 mi (80 km) 
so as to avoid long tows back to shore.
    COP will also support village Com-Stations in the Arctic 
communities and employ local advisors from the Chukchi Sea villages to 
provide consultation and guidance regarding the whale migration and 
subsistence hunt. They will provide advice to COP on ways to minimize 
and mitigate potential impacts to subsistence resources during the 
drilling season. Support activities, such as helicopter flights, could 
impact nearshore subsistence hunts. However, COP will use flight paths 
and agreed upon flight altitudes to avoid adverse impacts to hunts and 
will communicate regularly with the Com-Station.
    In the unlikely event of a major oil spill in the Chukchi 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. Additionally, COP developed an OSRP, which is currently under 
review by DOI and will also be reviewed by NOAA. COP has also 
incorporated several mitigation measures into its operational design to 
reduce further the risk of an oil spill. Based on the information 
available, the proposed mitigation measures that COP will implement, 
and the extremely low likelihood of a major oil spill occurring, NMFS 
has preliminarily determined that COP's activities will not have an 
unmitigable adverse impact on the availability of marine mammals for 
subsistence uses.

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 1, 2014, through October 
31, 2014.
    (2) This Authorization is valid only for activities associated with 
COP's 2014 Devils Paw, Chukchi Sea, exploration drilling program. The 
specific areas where COP's exploration drilling program will be 
conducted are within COP lease holdings in the Outer Continental Shelf 
Lease Sale 193 area in the Chukchi 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; minke whale; fin whale; humpback whale; 
killer 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) airgun array with a total discharge volume of 760 in\3\;
    (b) continuous drill rig sounds during active drilling operations 
and from support vessels in dynamic positioning mode; and
    (c) vessel sounds generated during active ice management.
    (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

[[Page 12582]]

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 5 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. For purposes of this 
Authorization, a group is defined as being three or more whales 
observed within a 547-yd (500-m) area and displaying behaviors of 
directed or coordinated activity (e.g., group feeding);
    (b) Avoid multiple changes in direction and speed when within 300 
yards (274 m) of whales and also operate the vessel(s) to avoid causing 
a whale to make multiple changes in direction;
    (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) Check the waters immediately adjacent to the vessel(s) to 
ensure that no whales will be injured when the propellers are engaged;
    (e) Vessels should remain as far offshore as weather and ice 
conditions allow and at least 5 mi (8 km) offshore during transit;
    (f) 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;
    (g) Utilize NMFS-qualified, vessel-based Protected Species 
Observers (PSOs) to visually watch for and monitor marine mammals near 
the drill rig or ice management vessels during active drilling, dynamic 
positioning, 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) and big-eye binoculars (25x150). 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;
    (h) 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 PSO, 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 PSO 
location.
    (iv) The ship's position, speed of support vessels, and 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.
    (v) Altitude and position of the aircraft if sightings are made 
during helicopter crew transfers.
    (i) 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;
    (j) PSOs will complete a training session on marine mammal 
monitoring, to be conducted shortly before the anticipated start of the 
2014 open-water season.
    (k) 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;
    (l) 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;
    (m) Within safe limits, the PSOs should be stationed where they 
have the best possible viewing. Viewing may not always be best from the 
ship bridge, and in some cases may be best from higher positions with 
less visual obstructions (e.g., flying bridge);
    (n) PSOs should be instructed to identify animals as unknown where 
appropriate rather than strive to identify a species if there is 
significant uncertainty;
    (o) PSOs should maximize their time with eyes on the water. This 
may require new means of recording data (e.g., audio recorder) or the 
presence of a data recorder so that the observers can simply relay 
information to them; and
    (p) PSOs should plot marine mammal sightings in near real-time for 
their vessel into a GIS software program and relay information 
regarding the animal(s)' position between platforms and vessels with 
emphasis placed on relaying sightings with the greatest potential to 
involve mitigation or reconsideration of the vessel's course.
    (8) VSP 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, COP 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 airgun array 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 is in

[[Page 12583]]

operation. For purposes of the field verification tests, described in 
condition 10(b)(i) below, the 180 dB radius for the airgun array is 
predicted to be 0.6 mi (920 m) and the 190 dB radius for the airgun 
array is predicted to be 525 ft (160 m). New radii will be used upon 
completion of the field verification tests described in the Monitoring 
Measures section below (condition 10(b)(i));
    (d) Implement a ``ramp-up'' procedure when starting up at the 
beginning of seismic operations, which means start the smallest gun 
first and double the number of operating airguns at one-minute 
intervals. 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 shutdown 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 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 shutdown and subsequent animal 
departure, airgun operations may resume following ramp-up procedures 
described in Condition 8(d) above;
    (h) VSP 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;
    (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; and
    (j) When utilizing the mitigation airgun, use a reduced duty cycle 
(e.g., 1 shot/min).
    (9) Subsistence Mitigation Measures: To ensure no unmitigable 
adverse impact on subsistence uses of marine mammals, the Holder of 
this Authorization shall:
    (a) Not enter the Chukchi Sea prior to July 1 to minimize effects 
on spring and early summer whaling;
    (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) Establish Com-Stations and Com-Station outposts. The Com 
Centers shall operate 24 hours/day during the 2012 bowhead whale hunt;
    (d) Employ local Inupiat communicators from the 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; and
    (f) Helicopters may not hover or circle above areas with groups of 
whales or within 0.5 mi (800 m) of such areas.
    (10) Monitoring Measures:
    (a) Vessel-based Monitoring: The Holder of this Authorization shall 
designate biologically-trained PSOs to be aboard the drill rig and ice 
management 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) Acoustic Monitoring:
    (i) Field Source Verification: the Holder of this Authorization is 
required to conduct sound source verification tests for the drill rig, 
support vessels in DP mode, 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. Initial results must be 
provided to NMFS within 120 hours of completing the analysis.
    (ii) The Holder of this Authorization shall deploy acoustic 
recorders in the U.S. Chukchi Sea in order to gain information on the 
distribution of marine mammals in the region. To the extent 
practicable, this program must be implemented as detailed in the 4MP.
    (11) Reporting Requirements: The Holder of this Authorization is 
required to:
    (a) Submit a sound source verification report to NMFS with the 
results for the drill rig, support vessels (including in DP mode), and 
the airguns. The reports should report down to the 120-dB radius in 10-
dB increments;
    (b) Submit daily PSO logs to NMFS;
    (c) 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) Sampling of the relative near-field around operations should 
be corrected for effort to provide the best possible estimates of 
marine mammals in EZs and exposure zones; and

[[Page 12584]]

    (ix) If, after the independent monitoring plan peer review changes 
are made to the monitoring program, those changes must be detailed in 
the report.
    (d) 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.
    (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), COP shall immediately take steps to 
cease operations and immediately report the incident to the Chief of 
the Permits and Conservation Division, Office of Protected Resources, 
NMFS, or his designee by phone or email, the Alaska Regional Office, 
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).
    Activities shall not resume until NMFS is able to review the 
circumstances of the prohibited take. NMFS shall work with COP to 
determine what is necessary to minimize the likelihood of further 
prohibited take and ensure MMPA compliance. COP may not resume their 
activities until notified by NMFS via letter, email, or telephone.
    (b) In the event that COP 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), 
COP will immediately report the incident to the Chief of the Permits 
and Conservation Division, Office of Protected Resources, NMFS, by 
phone or email, the Alaska Regional Office, 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 COP to determine 
whether modifications in the activities are appropriate.
    (c) In the event that COP 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), COP 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. COP 
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) COP 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 are three marine mammal species listed as endangered under 
the ESA with confirmed or possible occurrence in the proposed project 
area: the bowhead, humpback, and fin whales. There are two marine 
mammal species listed as threatened under the ESA with confirmed 
occurrence in the proposed project area: ringed and bearded seals. 
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 COP 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 COP 
for its 2014 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).

Proposed Authorization

    As a result of these preliminary determinations, NMFS proposes to 
authorize the take of marine mammals incidental to COP for its 2014 
open-water exploration drilling program, provided the previously 
mentioned mitigation, monitoring, and reporting requirements are 
incorporated.

    Dated: February 12, 2013.
Helen M. Golde,
Acting Director, Office of Protected Resources, National Marine 
Fisheries Service.
[FR Doc. 2013-03681 Filed 2-21-13; 8:45 am]
BILLING CODE 3510-22-P