[Federal Register Volume 79, Number 72 (Tuesday, April 15, 2014)]
[Notices]
[Pages 21354-21384]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2014-08352]



[[Page 21353]]

Vol. 79

Tuesday,

No. 72

April 15, 2014

Part II





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 a 3D Seismic Survey in Prudhoe Bay, 
Beaufort Sea, Alaska; Notice

  Federal Register / Vol. 79 , No. 72 / Tuesday, April 15, 2014 / 
Notices  

[[Page 21354]]


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DEPARTMENT OF COMMERCE

National Oceanic and Atmospheric Administration

RIN 0648-XD210


Takes of Marine Mammals Incidental to Specified Activities; 
Taking Marine Mammals Incidental to a 3D Seismic Survey in Prudhoe Bay, 
Beaufort Sea, Alaska

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 has received an application from BP Exploration (Alaska) 
Inc. (BP) for an Incidental Harassment Authorization (IHA) to take 
marine mammals, by harassment, incidental to conducting an ocean-bottom 
sensor seismic survey in Prudhoe Bay, Beaufort Sea, Alaska, during the 
2014 open water season. Pursuant to the Marine Mammal Protection Act 
(MMPA), NMFS is requesting comments on its proposal to issue an IHA to 
BP to incidentally take, by Level B harassment only, marine mammals 
during the specified activity.

DATES: Comments and information must be received no later than May 15, 
2014.

ADDRESSES: Comments on the application should be addressed to Jolie 
Harrison, Supervisor, Incidental Take Program, 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 
(e.g., name, address) voluntarily submitted by the commenter may be 
publicly accessible. Do not submit Confidential Business Information or 
otherwise sensitive or protected information.
    An electronic copy of the application containing a list of the 
references used in this document may be obtained by writing to the 
address specified above, telephoning the contact listed below (see FOR 
FURTHER INFORMATION CONTACT), or visiting the Internet at: http://www.nmfs.noaa.gov/pr/permits/incidental.htm. Documents cited in this 
notice may 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, other means of 
effecting the least practicable impact on the species or stock and its 
habitat, 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.''
    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

    On December 30, 2013, NMFS received an application from BP for the 
taking of marine mammals incidental to conducting a 3D ocean-bottom 
sensor (OBS) seismic survey. NMFS determined that the application was 
adequate and complete on February 14, 2014.
    BP proposes to conduct a 3D OBS seismic survey with a transition 
zone component on state and private lands and Federal and state waters 
in the Prudhoe Bay area of the Beaufort Sea during the open-water 
season of 2014. The proposed activity would occur between July 1 and 
September 30; however, airgun operations would cease on August 25. The 
following specific aspects of the proposed activity are likely to 
result in the take of marine mammals: airguns and pingers. Take, by 
Level B harassment only, of 9 marine mammal species is anticipated to 
result from the specified activity.

Description of the Specified Activity

Overview

    BP's proposed OBS seismic survey would utilize sensors located on 
the ocean bottom or buried below ground nearshore (surf zone) and 
onshore. A total of two seismic source vessels will be used during the 
proposed survey, each carrying two airgun sub-arrays. The discharge 
volume of each airgun sub-array will not exceed 620 cubic inches 
(in\3\). To limit the duration of the total survey, the source vessels 
will be operating in a flip-flop mode (i.e., alternating shots); this 
means that one vessel discharges airguns when the other vessel is 
recharging. The program is proposed to be conducted during the 2014 
open-water season.
    The purpose of the proposed OBS seismic survey is to obtain 
current, high-resolution seismic data to image existing reservoirs. The 
data will increase BP's understanding of the reservoir, allowing for 
more effective reservoir management. Existing datasets of the proposed 
survey area include the 1985 Niakuk and 1990 Point McIntyre vibroseis 
on ice surveys. Data from these two surveys were merged for 
reprocessing in 2004. A complete set of OBS data has not previously 
been acquired in the proposed survey area.

Dates and Duration

    The planned start date of receiver deployment is approximately July 
1, 2014, with seismic data acquisition beginning when open water 
conditions allow. This has typically been around July 15. Seismic 
survey data acquisition may take approximately 45 days to complete, 
which includes downtime for weather and other circumstances. Seismic 
data acquisition will occur on a 24-hour per day schedule with 
staggered crew changes. Receiver retrieval and demobilization of

[[Page 21355]]

equipment and support crew will be completed by the end of September. 
To limit potential impacts to the bowhead whale fall migration and 
subsistence hunting, airgun operations will cease by midnight on August 
25. Receiver and equipment retrieval and crew demobilization would 
continue after airgun operations end but would be completed by 
September 30. Therefore, the proposed dates for the IHA (if issued) are 
July 1 through September 30, 2014.

Specified Geographic Region

    The proposed seismic survey would occur in Federal and state waters 
in the Prudhoe Bay area of the Beaufort Sea, Alaska. The seismic survey 
project area lies mainly within the Prudhoe Bay Unit and also includes 
portions of the Northstar, Dewline, and Duck Island Units, as well as 
non-unit areas. Figures 1 and 2 in BP's application outline the 
proposed seismic acquisition areas. The project area encompasses 
approximately 190 mi\2\, comprised of approximately 129 mi\2\ in water 
depths of 3 ft and greater, 28 mi\2\ in waters less than 3 ft deep, and 
33 mi\2\ on land. The approximate boundaries of the project area are 
between 70[deg]16' N. and 70[deg]31' N. and between 147[deg]52' W. and 
148[deg]47' W. and include state and federal waters, as well as state 
and private lands. Activity outside the 190 mi\2\ area may include 
source vessels turning from one line to the other while using 
mitigation guns, vessel transits, and project support and logistics.

Detailed Description of Activities

    OBS seismic surveys are typically used to acquire 3D seismic data 
in water that is too shallow for towed streamer operations or too deep 
to have grounded ice in winter. Data acquired through this type of 
survey will allow for the generation of a 3D sub-surface image of the 
reservoir area. The generation of a 3D image requires the deployment of 
many parallel receiver lines spaced close together over the area of 
interest. The activities associated with the proposed OBS seismic 
survey include equipment and personnel mobilization and demobilization, 
housing and logistics, temporary support facilities, and seismic data 
acquisition.
1. Equipment and Personnel Mobilization and Demobilization
    Mobilization, demobilization, and support activities are primarily 
planned to occur at West Dock, East Dock, and Endicott. Other existing 
pads within the Prudhoe Bay Unit area may be utilized for equipment 
staging or support as necessary. All vessels are expected to be 
transported to the North Slope by truck. Any mobilization by truck does 
not have the potential to take marine mammals. It is possible that one 
of the vessels will be mobilized by sea past Barrow when ice conditions 
allow. The vessels will be prepared at the seismic contractor's base in 
Deadhorse, West Dock, or East Dock. Vessel preparation will include 
assembly of navigation and source equipment, testing receiver 
deployment and retrieval systems, loading recording and safety 
equipment, and initial fueling. Once assembled, the systems (including 
airguns) will be tested within the project area. Equipment will be 
retrieved as part of the operations and during demobilization. Receiver 
retrieval and demobilization of equipment and support crew will be 
completed by the end of September.
2. Housing and Logistics
    Approximately 220 people will be involved in the operation 
including seismic crew, management, mechanics, and Protected Species 
Observers (PSOs). Most of the crew will be accommodated at BP operated 
camps or Deadhorse. Some offshore crew will be housed on vessels.
    Personnel transportation between camps, pads, and support 
facilities will take place by trucks and crew transport buses traveling 
on existing gravel roads. This type of crew transfer does not have the 
potential to take marine mammals. Shallow-water craft such as Zodiac-
type vessels and ARKTOS\TM\ (and Northstar hovercraft if needed and 
available) will be used to transport equipment and crews to shallow 
water and surf-zone areas of the survey area not accessible by road; 
ARKTOS\TM\ will not be used in vegetated areas, including tundra. 
Helicopters will be used to transport equipment and personnel to 
onshore tundra areas, and crews on foot will deploy equipment onshore. 
Trucks may also be used on the existing road system to transfer survey 
equipment and crews to the onshore portions of the survey area 
accessible by road and pads. Helicopter operations will be supported in 
Deadhorse.
    Up to 10,000 gallons of fuel (mostly ultra-low sulfur diesel and 
small quantities of gasoline) may be temporarily stored on existing 
pads to support survey activities. Fuel may be transported to locations 
to refuel equipment. The vehicle transporting fuel to locations off 
pads (helicopter, boat, tracked buggy, or truck) will supply the 
necessary quantity of fuel at the time of transfer. Fueling of 
equipment may occur in floodplains and near water to accommodate marine 
and surf zone operations. All fueling will occur in accordance with 
applicable regulations and BP spill prevention practices.
3. Support Facilities
    West Dock, Endicott, and East Dock, as well as other existing 
Prudhoe Bay Unit infrastructure, will be utilized for seismic staging, 
crew transfers, resupply, and other support activities. Crew transfers 
and resupply may also occur at other nearby vessel accessible locations 
(e.g., by beaching) if needed. For protection from weather, vessels may 
anchor near West Dock, near the barrier islands, or other nearshore 
area locations.
    Receivers (i.e., nodes placed into cache bags) to be transported by 
helicopter via sling-load to the onsite project area for on-foot 
deployment may be temporarily staged on tundra adjacent to pads. These 
staging areas are not expected to exceed 200 ft by 200 ft and will be 
rotated as practicable to minimize tundra disturbance.
    Helicopter support for equipment and personnel transport is 
scheduled to take place during one shift per 24-hour day. The 
helicopter will be based at the Deadhorse airport. A few staging areas 
may be strategically located at existing pads or gravel locations in 
the Prudhoe Bay Unit to minimize flight time and weather exposure.
    A temporary flexi-float dock may be located at West Dock to provide 
support for vessel supply operations, personnel transfers, and 
refueling. The dock size will be a maximum of 170 x 30 ft and will be 
comprised of sections that will be fastened on location and secured 
with spuds to the seafloor. If needed, a smaller temporary dock (up to 
100 x 15 ft) may be used at Endicott for additional support during some 
operations in the eastern project area. Minimal and temporary 
disturbance to marine sediments is expected when docks are placed and 
removed.
4. Seismic Data Acquisition
    The proposed seismic survey will use sensors located on the ocean 
bottom or buried below ground nearshore (surf zone) and onshore and is 
described in more detail below. Sensors will be placed along north-
south oriented receiver lines, with a minimum line spacing of 1,320 ft. 
The sound source will be submerged compressed airgun arrays towed 
behind source vessels. Source lines will be oriented perpendicular to 
receiver lines with typical minimum line spacing of 550 ft. In certain 
situations, such as when lines have been modified to avoid cultural 
sites, mitigate impacts to wildlife, or

[[Page 21356]]

due to bathymetry or geographic features, additional infill source and 
receiver lines may be added to improve data imaging.
    Equipment and Vessels: Equipment will include geophones/receivers, 
airguns, nodes and batteries, helicopters, tracked drills, and vessels. 
Table 1 here and in BP's application lists the number and type of 
vessels and other vehicles anticipated to be used for the data 
acquisition. In the event that a specific vehicle or vessel is not 
available, a vehicle or vessel with similar parameters will be used.
[GRAPHIC] [TIFF OMITTED] TN15AP14.000

    Navigation and Data Management: Surveyors will deploy up to three 
navigation positioning base stations (survey control) onshore or on an 
island and may mark receiver locations in advance of the lay-out crews. 
Scouting of the project area and collecting bathymetry information 
necessary to identify site-specific conditions, such as water depth in 
near-shore areas will be performed prior to receiver deployment. A 
Differential Global Positioning System will be used for navigation. 
This navigation system connects to the onshore base stations and 
remotely links the operating systems on the vessels. The navigation 
system will display known obstructions, islands, identified areas of 
sensitivity, and pre-plotted source and receiver line positions; this 
information will be updated as necessary. The asset monitor will update 
the positions of each vessel in the survey area every few seconds 
providing the crew a quick display as to each vessel's position. Tide 
gauges will also be temporarily installed in the operation area. Tide 
gauges will be used to provide real-time water depth to ensure 
operations occur in the prescribed water depths. The tide gauge 
information will be input into the navigation system to provide real-
time assessment.
    Receiver Deployment and Retrieval: The survey area has been 
separated into three different zones based upon the different types of 
receivers that will be used and the method of receiver deployment and 
retrieval for that zone. Deployment and retrieval methods have been 
designed to facilitate complete equipment retrieval at the end of the 
survey. The three zones are: Offshore zone; surf zone; and onshore 
zone. Details on operations in each zone are provided next.
    The offshore zone is defined as waters of 3 ft or deeper. Receiver 
boats will be used for the deployment and retrieval of receivers 
(marine nodes) that will be placed in lines onto the ocean bottom at 
about 110 ft spacing. Receivers will not be placed east of the Endicott 
Main Production Island, and will therefore not be placed in mapped 
concentrations of the Boulder Patch. Acoustic pingers will be deployed 
on every second node to determine exact positions of the receivers. The 
pingers transmit at frequencies ranging from about 19-36 kHz and have 
an estimated source level of 188-193 dB re [mu]Pa at 1m.
    The surf zone includes waters up to 6 ft deep along the coastline, 
non-vegetated tidelands, and lands within the river delta areas that 
are intermittently submerged with tidal, precipitation, and storm surge 
events. ARKTOSTM and utility type vehicles equipped with a 
bit of approximately 4-

[[Page 21357]]

inch diameter will be used to either drill or flush the receivers to 
approximately 6 ft. Small vessels will then attach autonomous nodes to 
the receivers. The nodes will be protected from the water either 
through placement on specially designed floats anchored to the bottom 
or on support poles. Support poles will primarily be used in water less 
than 18 inches deep and in tidal surge areas to ensure that the nodes 
stay above surface waters and prevent them from becoming inundated as a 
result of fluctuating water levels. Receivers that are installed in the 
seabed may require warm water flushing to facilitate removal.
    The onshore zone is the vegetated area from the coastline inland. 
Autonomous node receivers with geophones will be used in this area. 
Helicopters will be the main method to transport land crews and 
equipment. Equipment will be bagged, with each bag holding several 
nodes. Multiple bags will be transported via sling load from the 
staging area to the receiver lines and temporarily cached. Bag drop 
zones will be 500 to 1,000 ft apart and will be cleared for the 
presence of nesting birds prior to use. Crews on foot will walk from 
bag to bag and lay out the equipment at the surveyed location. Vessels 
may also be used to transport personnel and equipment to a staging area 
on the beach, and vehicles may be used to transport personnel and 
equipment along the road system. Zodiac-type boats may be used in large 
lakes to deploy marine nodes. Boats, nodes, and crews will be 
transported via helicopter to and from the lakes.
    Nodes will be located on the ground surface, and the geophone(s) 
will be inserted approximately 3 ft below ground surface. Geophone 
installation will be either by hand using a planting pole or will be 
inserted into 1.5 inch diameter holes made with a hand-held drill. 
Support poles may be placed in lake margins and marshy areas of tundra 
as needed to ensure the nodes stay above surface waters and prevent 
them from becoming inundated as a result of fluctuating water levels. 
If conditions allow, geophones may be installed in the Sagavanirktok 
River Delta in early April until tundra closure using two tracked 
utility vehicle and a support vehicle. Upon completion of data 
acquisition and recording operations in a particular area, land crews 
will retrieve the nodes. Activities that occur onshore are not 
considered in the take assessment analysis in this proposed IHA.
    Source Vessel Operations: A total of two seismic source vessels 
will be used during the proposed survey. The source vessels will carry 
an airgun array that consists of two sub-arrays, however, it is 
possible that one of the source vessels will tow only one sub-array. 
The discharge volume of the sub-array will not exceed 620 in\3\. Each 
sub-array consists of eight airguns (2 x 110, 2 x 90, 2 x 70, and 2 x 
40 in\3\) totaling 16 guns for the two sub-arrays with a total 
discharge volume of 2 x 620 in\3\, or 1240 in\3\. The 620 in\3\ sub-
array has an estimated source level of ~218 decibels referenced to 1 
microPascal root mean squared (dB re 1 [mu]Pa rms) at 1 meter from the 
source. The estimated source level of the two sub-arrays combined is 
~224 dB re 1 [mu]Pa rms. In the shallowest areas, only one sub-array 
may be used for a given source vessel. Table 2 here and in BP's 
application summarizes the acoustic properties of the proposed airgun 
array. The smallest gun in the array (40 in\3\) or a separate 10 in\3\ 
airgun will be used for mitigation purposes.
    The airgun sub-arrays will be towed at a distance of approximately 
50 ft from the source vessel's stern at depths ranging from 
approximately 3 to 6 ft, depending on water depth and sea conditions. 
The source vessels will travel along pre-determined lines with a speed 
varying from 1 to 5 knots, mainly depending on the water depth.
    To limit the duration of the total survey, the source vessels will 
be operating in flip-flop mode (i.e., alternating shots); this means 
that one vessel discharges airguns when the other vessel is recharging. 
In some instances, only one source vessel will be operating, while the 
second source vessel will be engaged in refueling, maintenance, or 
other activities that do not require the operation of airguns. The 
expected shot interval for each source will be 10 to 12 seconds, 
resulting in a shot every 5 to 6 seconds due to the flip-flop mode of 
operation. The exact shot intervals will depend on the compressor 
capacity, which determines the time needed for the airguns to be 
recharged. Data will record autonomously on the nodes placed offshore, 
in the surf zone, and onshore and may be periodically checked for 
quality control.

Table 2--Proposed Airgun Array Configuration and Sound Source Signatures
      as Predicted by the Gundalf Airgun Array Model for 2 m Depth
------------------------------------------------------------------------
       Array specifics           620 in\3\ array      1240 in\3\ array
------------------------------------------------------------------------
Number of guns..............  Eight 2000 psi        Sixteen 2000 psi
                               sleeve airguns (2 x   sleeve airguns (4 x
                               110, 2 x 90, 2 x      110, 4 x 90, 4 x
                               70, and 2 x 40        70, and 4 x 40
                               in\3\) in one array.  in\3\), equally
                                                     divided over two
                                                     sub-arrays of eight
                                                     guns each.
Zero to peak................  6.96 bar-m (~237 dB   13.8 bar-m (~249 dB
                               re [mu]Pa @1 m).      re 1 [mu]Pa @1 m).
Peak to peak................  14.9 bar-m (~243 dB   29.8 bar-m (~243 dB
                               re [mu]Pa @1 m).      re 1 [mu]Pa @1 m).
RMS pressure................  0.82 bar-m (~218 dB   1.65 bar-m (~224 dB
                               re [mu]Pa @1 m).      re 1 [mu]Pa @1 m).
Dominant frequencies........  Typically less than   Typically less than
                               1 kHz.                1 kHz.
------------------------------------------------------------------------

 Description of Marine Mammals in the Area of the Specified Activity

    The Beaufort Sea supports a diverse assemblage of marine mammals. 
Table 3 lists the 12 marine mammal species under NMFS jurisdiction with 
confirmed or possible occurrence in the proposed project area.

                        Table 3--Marine Mammal Species With Confirmed or Possible Occurrence in the Proposed Seismic Survey Area
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           Common name                Scientific name           Status             Occurrence          Seasonality             Range          Abundance
--------------------------------------------------------------------------------------------------------------------------------------------------------
Odontocetes:
    Beluga whale (Beaufort Sea     Delphinapterus        ...................  Common.............  Mostly spring and    Russia to Canada...       39,258
     stock).                        leucas.                                                         fall with some in
                                                                                                    summer.

[[Page 21358]]

 
    Killer whale.................  Orcinus orca........  ...................  Occasional/          Mostly summer and    California to                552
                                                                               Extralimital.        early fall.          Alaska.
    Harbor porpoise..............  Phocoena phocoena...  ...................  Occasional/          Mostly summer and    California to             48,215
                                                                               Extralimital.        early fall.          Alaska.
    Narwhal......................  Monodon monoceros...  ...................  ...................  ...................  ...................       45,358
Mysticetes:
    Bowhead whale................  Balaena mysticetus..  Endangered;          Common.............  Mostly spring and    Russia to Canada...       16,892
                                                          Depleted.                                 fall with some in
                                                                                                    summer.
    Gray whale...................  Eschrichtius          ...................  Somewhat common....  Mostly summer......  Mexico to the U.S.        19,126
                                    robustus.                                                                            Arctic Ocean.
    Minke whale..................  Balaenoptera          ...................  ...................  ...................  ...................    810-1,003
                                    acutorostrata.
    Humpback whale (Central North  Megaptera             Endangered;          ...................  ...................  ...................       21,063
     Pacific stock).                novaeangliae.         Depleted.
Pinnipeds:
    Bearded seal (Beringia         Erigathus barbatus..  Threatened;          Common.............  Spring and summer..  Bering, Chukchi,         155,000
     distinct population segment).                        Depleted.                                                      and Beaufort Seas.
    Ringed seal (Arctic stock)...  Phoca hispida.......  Threatened;          Common.............  Year round.........  Bering, Chukchi,         300,000
                                                          Depleted.                                                      and Beaufort Seas.
    Spotted seal.................  Phoca largha........  ...................  Common.............  Summer.............  Japan to U.S.            141,479
                                                                                                                         Arctic Ocean.
    Ribbon seal..................  Histriophoca          Species of concern.  Occasional.........  Summer.............  Russia to U.S.            49,000
                                    fasciata.                                                                            Arctic Ocean.
--------------------------------------------------------------------------------------------------------------------------------------------------------
Endangered, threatened, or species of concern under the Endangered Species Act (ESA); Depleted under the MMPA.

    The highlighted (grayed out) species in Table 3 are so rarely 
sighted in the central Alaskan Beaufort Sea that their presence in the 
proposed project area, and therefore take, is unlikely. Minke whales 
are relatively common in the Bering and southern Chukchi seas and have 
recently also been sighted in the northeastern Chukchi Sea (Aerts et 
al., 2013; Clarke et al., 2013). Minke whales are rare in the Beaufort 
Sea. They have not been reported in the Beaufort Sea during the Bowhead 
Whale Aerial Survey Project/Aerial Surveys of Arctic Marine Mammals 
(BWASP/ASAMM) surveys (Clarke et al., 2011, 2012; 2013; Monnet and 
Treacy, 2005), and there was only one observation in 2007 during 
vessel-based surveys in the region (Funk et al., 2010). Humpback whales 
have not generally been found in the Arctic Ocean. However, subsistence 
hunters have spotted humpback whales in low numbers around Barrow, and 
there have been several confirmed sightings of humpback whales in the 
northeastern Chukchi Sea in recent years (Aerts et al., 2013; Clarke et 
al., 2013). The first confirmed sighting of a humpback whale in the 
Beaufort Sea was recorded in August 2007 (Hashagen et al., 2009) when a 
cow and calf were observed 54 mi east of Point Barrow. No additional 
sightings have been documented in the Beaufort Sea. Narwhal are common 
in the waters of northern Canada, west Greenland, and in the European 
Arctic, but rarely occur in the Beaufort Sea (COSEWIC, 2004). Only a 
handful of sightings have occurred in Alaskan waters (Allen and 
Angliss, 2013). These three species are not considered further in this 
proposed IHA notice. Both the walrus and the polar bear could occur in 
the U.S. Beaufort Sea; however, these species are managed by the U.S. 
Fish and Wildlife Service (USFWS) and are not considered further in 
this Notice of Proposed IHA.
    The Beaufort Sea is a main corridor of the bowhead whale migration 
route. The main migration periods occur in spring from April to June 
and in fall from late August/early September through October to early 
November. During the fall migration, several locations in the U.S. 
Beaufort Sea serve as feeding grounds for bowhead whales. Small numbers 
of bowhead whales that remain in the U.S. Arctic Ocean during summer 
also feed in these areas. The U.S. Beaufort Sea is not a main feeding 
or calving area for any other cetacean species. Ringed seals breed and 
pup in the Beaufort Sea; however, this does not occur during the summer 
or early fall. Further information on the biology and local 
distribution of these species can be found in BP's application (see 
ADDRESSES) and the NMFS Marine Mammal Stock Assessment Reports, which 
are available online at: http://www.nmfs.noaa.gov/pr/species/.

Potential Effects of the Specified Activity on Marine Mammals

    This section includes a summary and discussion of the ways that the 
types of stressors associated with the specified activity (e.g., 
seismic airgun and pinger operation, vessel movement) have been 
observed to or are thought to impact marine mammals. This section may 
include a discussion of known effects that do not rise to the level of 
an MMPA take (for example, with acoustics, we may include a discussion 
of studies that showed animals not reacting at all to sound or 
exhibiting barely measurable avoidance). The discussion may also 
include reactions that we consider to rise to the level of a take and 
those that we do not consider to rise to the level of a take. This 
section is intended as a background of potential effects and does not 
consider either the specific manner in which this activity will be 
carried out or the mitigation that will be implemented or how either of 
those will shape the anticipated impacts from this specific activity. 
The ``Estimated Take by Incidental Harassment'' section later in this 
document will include a quantitative analysis of the number of 
individuals that are expected to be taken by this activity. The 
``Negligible Impact Analysis'' section will include the analysis of how 
this specific activity will impact marine mammals and will consider the 
content of this section, the ``Estimated Take by Incidental 
Harassment'' section, the ``Mitigation'' section, and the ``Anticipated 
Effects on

[[Page 21359]]

Marine Mammal Habitat'' section to draw conclusions regarding the 
likely impacts of this activity on the reproductive success or 
survivorship of individuals and from that on the affected marine mammal 
populations or stocks.

Background on Sound

    Sound is a physical phenomenon consisting of minute vibrations that 
travel through a medium, such as air or water, and is generally 
characterized by several variables. Frequency describes the sound's 
pitch and is measured in hertz (Hz) or kilohertz (kHz), while sound 
level describes the sound's intensity and is measured in decibels (dB). 
Sound level increases or decreases exponentially with each dB of 
change. The logarithmic nature of the scale means that each 10-dB 
increase is a 10-fold increase in acoustic power (and a 20-dB increase 
is then a 100-fold increase in power). A 10-fold increase in acoustic 
power does not mean that the sound is perceived as being 10 times 
louder, however. Sound levels are compared to a reference sound 
pressure (micro-Pascal) to identify the medium. For air and water, 
these reference pressures are ``re: 20 [mu]Pa'' and ``re: 1 [mu]Pa,'' 
respectively. Root mean square (RMS) is the quadratic mean sound 
pressure over the duration of an impulse. RMS is calculated by squaring 
all of the sound amplitudes, averaging the squares, and then taking the 
square root of the average (Urick, 1975). RMS accounts for both 
positive and negative values; squaring the pressures makes all values 
positive so that they may be accounted for in the summation of pressure 
levels (Hastings and Popper, 2005). This measurement is often used in 
the context of discussing behavioral effects, in part, because 
behavioral effects, which often result from auditory cues, may be 
better expressed through averaged units rather than by peak pressures.

Acoustic Impacts

    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) to 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 
30 kHz;
     Mid-frequency cetaceans (32 species of dolphins, six 
species of larger toothed whales, and 19 species of beaked and 
bottlenose whales): functional hearing is estimated to occur between 
approximately 150 Hz and 160 kHz;
     High frequency cetaceans (eight species of true porpoises, 
six species of river dolphins, Kogia, the franciscana, and four species 
of cephalorhynchids): functional hearing is estimated to occur between 
approximately 200 Hz and 180 kHz;
     Phocid pinnipeds in Water: functional hearing is estimated 
to occur between approximately 75 Hz and 100 kHz; and
     Otariid pinnipeds in Water: functional hearing is 
estimated to occur between approximately 100 Hz and 40 kHz.
    As mentioned previously in this document, nine marine mammal 
species (five cetaceans and four phocid pinnipeds) may occur in the 
proposed seismic survey area. Of the five cetacean species likely to 
occur in the proposed project area and for which take is requested, two 
are classified as low-frequency cetaceans (i.e., bowhead and gray 
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). A species functional 
hearing group is a consideration when we analyze the effects of 
exposure to sound on marine mammals.
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). 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). The airgun arrays used in the Weir (2008) 
study were much larger than the array proposed for use during this 
seismic survey (total discharge volumes of 620 to 1,240 in\3\). 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. (1995) found that vessel noise does not seem to 
strongly affect pinnipeds that are already in the water. Richardson et 
al. (1995) 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.
2. Masking
    Masking is the obscuring of sounds of interest by other sounds, 
often at similar frequencies. Marine mammals use acoustic signals for a 
variety of purposes, which differ among species, but include 
communication between individuals, navigation, foraging, reproduction, 
avoiding predators, and learning about their environment (Erbe and 
Farmer, 2000; Tyack, 2000). Masking, or auditory interference, 
generally occurs when sounds in the environment are louder than, and of 
a similar frequency as, auditory signals an animal is trying to 
receive. Masking is a phenomenon that affects animals that are trying 
to receive acoustic information about their environment, including 
sounds from other members of their species, predators, prey, and sounds 
that allow them to orient in their environment. Masking these acoustic 
signals can disturb the behavior of individual animals, groups of 
animals, or entire populations.

[[Page 21360]]

    Masking occurs when anthropogenic sounds and signals (that the 
animal utilizes) overlap at both spectral and temporal scales. For the 
airgun sound generated from the proposed seismic survey, sound will 
consist of low frequency (under 500 Hz) pulses with extremely short 
durations (less than one second). Lower frequency man-made sounds are 
more likely to affect detection of communication calls and other 
potentially important natural sounds such as surf and prey noise. There 
is little concern regarding masking near the sound source due to the 
brief duration of these pulses and relatively longer silence between 
airgun shots (approximately 5-6 seconds). However, at long distances 
(over tens of kilometers away), due to multipath propagation and 
reverberation, the durations of airgun pulses can be ``stretched'' to 
seconds with long decays (Madsen et al., 2006), although the intensity 
of the sound is greatly reduced.
    This 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., 2009) and cause 
increased stress levels (e.g., Foote et al., 2004; Holt et al., 2009). 
Marine mammals are thought to be able to compensate for masking by 
adjusting their acoustic behavior by shifting call frequencies, and/or 
increasing call volume and vocalization rates. For example, blue whales 
are found to increase call rates when exposed to seismic survey noise 
in the St. Lawrence Estuary (Di Iorio and Clark, 2010). The North 
Atlantic right whales exposed to high shipping noise increase call 
frequency (Parks et al., 2007), while some humpback whales respond to 
low-frequency active sonar playbacks by increasing song length (Miller 
el al., 2000). Bowhead whale calls are frequently detected in the 
presence of seismic pulses, although the number of calls detected may 
sometimes be reduced (Richardson et al., 1986; Greene et al., 1999), 
possibly because animals moved away from the sound source or ceased 
calling (Blackwell et al., 2013). Additionally, beluga whales have been 
known to change their vocalizations in the presence of high background 
noise possibly to avoid masking calls (Au et al., 1985; Lesage et al., 
1999; Scheifele et al., 2005). 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., 1995). 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 sounds by improving 
the effective signal-to-noise ratio. In the cases of higher frequency 
hearing by the bottlenose dolphin, beluga whale, and killer whale, 
empirical evidence confirms that masking depends strongly on the 
relative directions of arrival of sound signals and the masking noise 
(Penner et al., 1986; Dubrovskiy, 1990; Bain et al., 1993; Bain and 
Dahlheim, 1994). Toothed whales, and probably other marine mammals as 
well, have additional capabilities besides directional hearing that can 
facilitate detection of sounds in the presence of background noise. 
There is evidence that some toothed whales can shift the dominant 
frequencies of their echolocation signals from a frequency range with a 
lot of ambient noise toward frequencies with less noise (Au et al., 
1974, 1985; Moore and Pawloski, 1990; Thomas and Turl, 1990; Romanenko 
and Kitain, 1992; Lesage et al., 1999). A few marine mammal species are 
known to increase the source levels or alter the frequency of their 
calls in the presence of elevated sound levels (Dahlheim, 1987; Au, 
1993; Lesage et al., 1993, 1999; Terhune, 1999; Foote et al., 2004; 
Parks et al., 2007, 2009; Di Iorio and Clark, 2009; Holt et al., 2009).
    These data demonstrating adaptations for reduced masking pertain 
mainly to the very high frequency echolocation signals of toothed 
whales. There is less information about the existence of corresponding 
mechanisms at moderate or low frequencies or in other types of marine 
mammals. For example, Zaitseva et al. (1980) found that, for the 
bottlenose dolphin, the angular separation between a sound source and a 
masking noise source had little effect on the degree of masking when 
the sound frequency was 18 kHz, in contrast to the pronounced effect at 
higher frequencies. Directional hearing has been demonstrated at 
frequencies as low as 0.5-2 kHz in several marine mammals, including 
killer whales (Richardson et al., 1995). This ability may be useful in 
reducing masking at these frequencies. In summary, high levels of sound 
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.
3. Behavioral Disturbance
    Marine mammals may behaviorally react when exposed to anthropogenic 
sound. These behavioral reactions are often shown as: changing 
durations of surfacing and dives, number of blows per surfacing, or 
moving direction and/or speed; reduced/increased vocal activities; 
changing/cessation of certain behavioral activities (such as 
socializing or feeding); visible startle response or aggressive 
behavior (such as tail/fluke slapping or jaw clapping); avoidance of 
areas where sound sources are located; and/or flight responses (e.g., 
pinnipeds flushing into water from haulouts or rookeries).
    The biological significance of many of these behavioral 
disturbances is difficult to predict, especially if the detected 
disturbances appear minor. However, the consequences of behavioral 
modification have the potential to be biologically significant if the 
change affects growth, survival, or reproduction. Examples of 
significant behavioral modifications include:
     Drastic change in diving/surfacing patterns (such as those 
thought to be causing beaked whale stranding due to exposure to 
military mid-frequency tactical sonar);
     Habitat abandonment due to loss of desirable acoustic 
environment; and
     Cessation of feeding or social interaction.
    The onset of behavioral disturbance from anthropogenic noise 
depends on both external factors (characteristics of

[[Page 21361]]

noise sources and their paths) and the receiving animals (hearing, 
motivation, experience, demography, current activity, reproductive 
state) and is also difficult to predict (Gordon et al., 2004; Southall 
et al., 2007; Ellison et al., 2011).
    Mysticetes: 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 BP's proposed survey (total discharge volume 
of 640 in\3\), distances to received levels in the 160 dB re 1 [mu]Pa 
rms range are estimated to be 0.5-3 mi (0.8-5 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 begin to show avoidance 
reactions at a received level of about 160-170 dB re 1 [mu]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. In any event, the proposed survey will 
occur in summer (July through late August) when most bowhead whales are 
commonly feeding in the Mackenzie River Delta, Canada.
    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. (1995) 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., 1995 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., 1995 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., 1995 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., 1995) 
observed that migrating gray whales rarely exhibited noticeable 
reactions to a straight-line overflight by a Twin Otter at 197 ft (60 
m) altitude.

[[Page 21362]]

    Odontocetes: Few systematic data are available describing reactions 
of toothed whales to noise pulses. 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). Miller et al. (2009) conducted at-sea 
experiments where reactions of sperm whales were monitored through the 
use of controlled sound exposure experiments from large airgun arrays 
consisting of 20-guns and 31-guns. Of 8 sperm whales observed, none 
changed their behavior when exposed to either a ramp-up at 4-8 mi (7-13 
km) or full array exposures at 0.6-8 mi (1-13 km).
    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 in certain geographic areas) 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 10-20 km (6.2-12.4 mi) of an active seismic 
vessel. These results were consistent with the low number of beluga 
sightings reported by observers aboard the seismic vessel, suggesting 
that some belugas might have been avoiding the seismic operations at 
distances of 10-20 km (6.2-12.4 mi) (Miller et al., 2005).
    Captive bottlenose dolphins and (of more relevance in this project) 
beluga whales exhibit changes in behavior when exposed to strong pulsed 
sounds similar in duration to those typically used in seismic surveys 
(Finneran et al., 2002, 2005). However, the animals tolerated high 
received levels of sound (pk-pk level >200 dB re 1 [mu]Pa) before 
exhibiting aversive behaviors.
    Observers stationed on seismic vessels operating off the United 
Kingdom from 1997-2000 have provided data on the occurrence and 
behavior of various toothed whales exposed to seismic pulses (Stone, 
2003; Gordon et al., 2004). Killer whales were found to be 
significantly farther from large airgun arrays during periods of 
shooting compared with periods of no shooting. The displacement of the 
median distance from the array was approximately 0.5 km (0.3 mi) or 
more. Killer whales also appear to be more tolerant of seismic shooting 
in deeper water.
    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.
    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.
    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. Monitoring work 
in the Alaskan Beaufort Sea during 1996-2001 provided considerable 
information regarding the behavior of Arctic ice 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 100 m (328 ft) to a few hundreds of meters, and 
many seals remained within 100-200 m (328-656 ft) 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., 1995). 
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.
    Blackwell et al. (2004) 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. (2004) 
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., 1995; Born 
et al., 1999).
4. Threshold Shift (Noise-induced Loss of Hearing)
    When animals exhibit reduced hearing sensitivity (i.e., sounds must 
be louder for an animal to detect them) following exposure to an 
intense sound or sound for long duration, it is referred to as a noise-
induced threshold shift (TS). An animal can experience temporary 
threshold shift (TTS) or permanent threshold shift (PTS). TTS can last 
from minutes or hours to days (i.e., there is complete recovery), can 
occur in specific frequency ranges (i.e., an animal might only have a 
temporary loss of hearing sensitivity between the frequencies of 1 and 
10 kHz), and can be of varying amounts (for example, an animal's 
hearing sensitivity might be reduced initially by only 6 dB or reduced 
by 30 dB). PTS is permanent, but some recovery is possible. PTS can 
also occur in a specific frequency range and amount as mentioned above 
for TTS.
    The following physiological mechanisms are thought to play a role

[[Page 21363]]

in inducing auditory TS: effects to sensory hair cells in the inner ear 
that reduce their sensitivity, modification of the chemical environment 
within the sensory cells, residual muscular activity in the middle ear, 
displacement of certain inner ear membranes, increased blood flow, and 
post-stimulatory reduction in both efferent and sensory neural output 
(Southall et al., 2007). The amplitude, duration, frequency, temporal 
pattern, and energy distribution of sound exposure all can affect the 
amount of associated TS and the frequency range in which it occurs. As 
amplitude and duration of sound exposure increase, so, generally, does 
the amount of TS, along with the recovery time. For intermittent 
sounds, less TS could occur than compared to a continuous exposure with 
the same energy (some recovery could occur between intermittent 
exposures depending on the duty cycle between sounds) (Kryter et al., 
1966; Ward, 1997). For example, one short but loud (higher SPL) sound 
exposure may induce the same impairment as one longer but softer sound, 
which in turn may cause more impairment than a series of several 
intermittent softer sounds with the same total energy (Ward, 1997). 
Additionally, though TTS is temporary, prolonged exposure to sounds 
strong enough to elicit TTS, or shorter-term exposure to sound levels 
well above the TTS threshold, can cause PTS, at least in terrestrial 
mammals (Kryter, 1985). Although in the case of the proposed seismic 
survey, animals are not expected to be exposed to sound levels high for 
a long enough period to result in PTS.
    PTS is considered auditory injury (Southall et al., 2007). 
Irreparable damage to the inner or outer cochlear hair cells may cause 
PTS; however, other mechanisms are also involved, such as exceeding the 
elastic limits of certain tissues and membranes in the middle and inner 
ears and resultant changes in the chemical composition of the inner ear 
fluids (Southall et al., 2007).
    Although the published body of scientific literature contains 
numerous theoretical studies and discussion papers on hearing 
impairments that can occur with exposure to a loud sound, only a few 
studies provide empirical information on the levels at which noise-
induced loss in hearing sensitivity occurs in nonhuman animals. For 
marine mammals, published data are limited to the captive bottlenose 
dolphin, beluga, harbor porpoise, and Yangtze finless porpoise 
(Finneran et al., 2000, 2002b, 2003, 2005a, 2007, 2010a, 2010b; 
Finneran and Schlundt, 2010; Lucke et al., 2009; Mooney et al., 2009a, 
2009b; Popov et al., 2011a, 2011b; Kastelein et al., 2012a; Schlundt et 
al., 2000; Nachtigall et al., 2003, 2004). For pinnipeds in water, data 
are limited to measurements of TTS in harbor seals, an elephant seal, 
and California sea lions (Kastak et al., 1999, 2005; Kastelein et al., 
2012b).
    Marine mammal hearing plays a critical role in communication with 
conspecifics, and 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 
(similar to those discussed in auditory masking, below). 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 occurs 
during a time 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 time when communication is critical 
for successful mother/calf interactions could have more serious 
impacts. Also, depending on the degree and frequency range, the effects 
of PTS on an animal could range in severity, although it is considered 
generally more serious because it is a permanent condition. Of note, 
reduced hearing sensitivity as a simple function of aging has been 
observed in marine mammals, as well as humans and other taxa (Southall 
et al., 2007), so we can infer that strategies exist for coping with 
this condition to some degree, though likely not without cost.
    Marine mammals are unlikely to be exposed to received levels of 
seismic pulses strong enough to cause more than slight TTS, and, given 
the higher level of sound necessary to cause PTS, it is even less 
likely that PTS could occur as a result of the proposed seismic survey.
5. Non-Auditory Physical Effects
    Non-auditory physical effects might 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. 
Some marine mammal species (i.e., beaked whales) may be especially 
susceptible to injury and/or stranding when exposed to strong pulsed 
sounds.
    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 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

[[Page 21364]]

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, we assume that reducing a marine mammal's ability to gather 
information about its environment and communicate with other members of 
its species would induce stress, based on data that terrestrial animals 
exhibit those responses under similar conditions (NRC, 2003) and 
because marine mammals 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. 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.
    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 project 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. There is no definitive evidence that any of 
these effects occur even for marine mammals in close proximity to large 
arrays of airguns, which are not proposed for use during this program. 
In addition, marine mammals that show behavioral avoidance of industry 
activities, including bowheads, belugas, and some pinnipeds, are 
especially unlikely to incur non-auditory impairment or other physical 
effects.
6. Stranding and Mortality
    Marine mammals close to underwater detonations of high explosive 
can be killed or severely injured, and the auditory organs are 
especially susceptible to injury (Ketten et al., 1993; Ketten, 1995). 
Airgun pulses are less energetic and their peak amplitudes have slower 
rise times. To date, there is no evidence that serious injury, death, 
or stranding by marine mammals can occur from exposure to airgun 
pulses, even in the case of large airgun arrays. Additionally, BP's 
project will use medium sized airgun arrays in shallow water. NMFS does 
not expect any marine mammals will incur serious injury or mortality in 
the shallow waters of Prudhoe Bay or strand as a result of the proposed 
seismic survey.
7. Potential Effects From Pingers on Marine Mammals
    Active acoustic sources other than the airguns have been proposed 
for BP's 2014 seismic survey in Prudhoe Bay, Beaufort Sea, Alaska. The 
specifications for the pingers (source levels and frequency ranges) 
were provided earlier in this document. In general, the potential 
effects of this equipment on marine mammals are similar to those from 
the airguns, except the magnitude of the impacts is expected to be much 
less due to the lower intensity of the source.

Vessel Impacts

    Vessel activity and noise associated with vessel activity will 
temporarily increase in the action area during BP's seismic survey as a 
result of the operation of 8-10 vessels. To minimize the effects of 
vessels and noise associated with vessel activity, BP will alter speed 
if a marine mammal gets too

[[Page 21365]]

close to a vessel. In addition, source vessels will be operating at 
slow speed (1-5 knots) when conducting surveys. Marine mammal 
monitoring observers will alert vessel captains as animals are detected 
to ensure safe and effective measures are applied to avoid coming into 
direct contact with marine mammals. Therefore, NMFS neither anticipates 
nor authorizes takes of marine mammals from ship strikes.
    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.
    Odontocetes, such as beluga whales, killer whales, and harbor 
porpoises, often show tolerance to vessel activity; however, they may 
react at long distances if they are confined by ice, shallow water, or 
were previously harassed by vessels (Richardson et al., 1995). Beluga 
whale response to vessel noise varies greatly from tolerance to extreme 
sensitivity depending on the activity of the whale and previous 
experience with vessels (Richardson et al., 1995). Reactions to vessels 
depends on whale activities and experience, habitat, boat type, and 
boat behavior (Richardson et al., 1995) and may include behavioral 
responses, such as altered headings or avoidance (Blane and Jaakson, 
1994; Erbe and Farmer, 2000); fast swimming; changes in vocalizations 
(Lesage et al., 1999; Scheifele et al., 2005); and changes in dive, 
surfacing, and respiration patterns.
    There are few data published on pinniped responses to vessel 
activity, and most of the information is anecdotal (Richardson et al., 
1995). Generally, sea lions in water show tolerance to close and 
frequently approaching vessels and sometimes show interest in fishing 
vessels. They are less tolerant when hauled out on land; however, they 
rarely react unless the vessel approaches within 100-200 m (330-660 ft; 
reviewed in Richardson et al., 1995).
    The addition of 8-10 vessels and noise due to vessel operations 
associated with the seismic survey is not expected to have effects that 
could cause significant or long-term consequences for individual marine 
mammals or their populations.

Anticipated Effects on Marine Mammal Habitat

    The primary potential impacts to marine mammal habitat and other 
marine species are associated with elevated sound levels produced by 
airguns and other active acoustic sources. However, other potential 
impacts to the surrounding habitat from physical disturbance are also 
possible. This section describes the potential impacts to marine mammal 
habitat from the specified activity. Because the marine mammals in the 
area feed on fish and/or invertebrates there is also information on the 
species typically preyed upon by the marine mammals in the area.

Common Marine Mammal Prey in the Project Area

    All 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). When feeding in 
relatively shallow areas, bowheads feed throughout the water column. 
However, feeding is concentrated at depths where zooplankton is 
concentrated (Wursig et al., 1984, 1989; Richardson [ed.], 1987; 
Griffiths et al., 2002). Lowry and Sheffield (2002) found that copepods 
and euphausiids were the most common prey found in stomach samples from 
bowhead whales harvested in the Kaktovik area from 1979 to 2000. Areas 
to the east of Barter Island (which is approximately 120 mi east of 
BP's proposed seismic area) 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).
    Recent articles and reports have noted bowhead whales feeding in 
several areas of the U.S. Beaufort Sea. The Barrow area is commonly 
used as a feeding area during spring and fall, with a higher proportion 
of photographed individuals displaying evidence of feeding in fall 
rather than spring (Mocklin, 2009). A bowhead whale feeding ``hotspot'' 
(Okkonen et al., 2011) commonly forms on the western Beaufort Sea shelf 
off Point Barrow in late summer and fall. Favorable conditions 
concentrate euphausiids and copepods, and bowhead whales congregate to 
exploit the dense prey (Ashjian et al., 2010, Moore et al., 2010; 
Okkonen et al., 2011). Surveys have also noted bowhead whales feeding 
in the Camden Bay area during the fall (Koski and Miller, 2009; 
Quakenbush et al., 2010).
    The 2006-2008 BWASP Final Report (Clarke et al., 2011a) and the 
2009 BWASP Final Report (Clarke et al., 2011b) note sightings of 
feeding bowhead whales in the Beaufort Sea during the fall season. 
During that 4 year period, the largest groups of feeding whales were 
sighted between Smith Bay and Point Barrow (hundreds of miles to the 
west of Prudhoe Bay), and none were sighted feeding in Camden Bay 
(Clarke et al., 2011a,b). Clarke and Ferguson (undated) examined the 
raw BWASP data from the years 2000-2009. They noted that feeding 
behavior was noted more often in September than October and that while 
bowheads were observed feeding throughout the study area (which 
includes the entire U.S. Beaufort Sea), sightings were less frequent in 
the central Alaskan Beaufort than they were east of Kaktovik and west 
of Smith Bay. Additionally, Clarke and Ferguson (undated) and Clarke et 
al. (2011b) refer to information from Ashjian et al. (2010), which 
describes the importance of wind-driven currents that produce favorable 
feeding conditions for bowhead whales in the area between Smith Bay and 
Point Barrow. Increased winds in that area may be increasing the 
incidence of upwelling, which in turn may be the reason for increased 
sightings of feeding bowheads in the area. Clarke and Ferguson 
(undated) also note that the incidence of feeding bowheads in the 
eastern Alaskan Beaufort Sea has decreased since the early 1980s.
    Beluga whales feed on a variety of fish, shrimp, squid and octopus 
(Burns and Seaman, 1985). Very few beluga whales occur nearshore; their 
main migration route is much further

[[Page 21366]]

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

Potential Impacts From Sound Generation

    With regard to fish as a prey source for odontocetes and seals, 
fish are known to hear and react to sounds and to use sound to 
communicate (Tavolga et al., 1981) and possibly avoid predators (Wilson 
and Dill, 2002). Experiments have shown that fish can sense both the 
strength and direction of sound (Hawkins, 1981). Primary factors 
determining whether a fish can sense a sound signal, and potentially 
react to it, are the frequency of the signal and the strength of the 
signal in relation to the natural background noise level.
    Fishes produce sounds that are associated with behaviors that 
include territoriality, mate search, courtship, and aggression. It has 
also been speculated that sound production may provide the means for 
long distance communication and communication under poor underwater 
visibility conditions (Zelick et al., 1999), although the fact that 
fish communicate at low-frequency sound levels where the masking 
effects of ambient noise are naturally highest suggests that very long 
distance communication would rarely be possible. Fishes have evolved a 
diversity of sound generating organs and acoustic signals of various 
temporal and spectral contents. Fish sounds vary in structure, 
depending on the mechanism used to produce them (Hawkins, 1993). 
Generally, fish sounds are predominantly composed of low frequencies 
(less than 3 kHz).
    Since objects in the water scatter sound, fish are able to detect 
these objects through monitoring the ambient noise. Therefore, fish are 
probably able to detect prey, predators, conspecifics, and physical 
features by listening to environmental sounds (Hawkins, 1981). There 
are two sensory systems that enable fish to monitor the vibration-based 
information of their surroundings. The two sensory systems, the inner 
ear and the lateral line, constitute the acoustico-lateralis system.
    Although the hearing sensitivities of very few fish species have 
been studied to date, it is becoming obvious that the intra- and inter-
specific variability is considerable (Coombs, 1981). Nedwell et al. 
(2004) compiled and published available fish audiogram information. A 
noninvasive electrophysiological recording method known as auditory 
brainstem response is now commonly used in the production of fish 
audiograms (Yan, 2004). Generally, most fish have their best hearing in 
the low-frequency range (i.e., less than 1 kHz). Even though some fish 
are able to detect sounds in the ultrasonic frequency

[[Page 21367]]

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 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 BP's proposed survey.
    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). In calm 
weather, ambient noise levels in audible parts of the spectrum lie 
between 60 dB to 100 dB.
    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 [mu]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 [mu]Pa. They noted:
     Startle responses at received levels of 200-205 dB re 1 
[mu]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 [mu]Pa may cause subtle changes in behavior. Pulses at 
levels of 180 dB may cause noticeable changes in behavior (Chapman and 
Hawkins, 1969; Pearson et al., 1992; Skalski et al., 1992). It also 
appears that fish often habituate to repeated strong sounds rather 
rapidly, on time scales of minutes to an hour. However, the habituation 
does not endure, and resumption of the strong sound source may again 
elicit disturbance responses from the same fish.
    Some of the fish species found in the Arctic are prey sources for 
odontocetes and pinnipeds. A reaction by fish to sounds produced by 
BP's proposed survey 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. 
Impacts on fish behavior are predicted to be inconsequential. Thus, 
feeding odontocetes and pinnipeds would not be adversely affected by 
this minimal loss or scattering, if any, of reduced prey abundance.
    Some mysticetes, including bowhead whales, feed on concentrations 
of zooplankton. Some feeding bowhead whales may occur in the Alaskan 
Beaufort Sea in July and August, but feeding bowheads are more likely 
to occur in the area after the cessation of airgun operations. 
Reactions of zooplankton to sound are, for the most part, not known. 
Their ability to move significant distances is limited or nil, 
depending on the type of zooplankton. Behavior of zooplankters is not 
expected to be affected by the survey. These animals have exoskeletons 
and no air bladders. Many crustaceans can make sounds, and some 
crustacea and other invertebrates have some type of sound receptor. A 
reaction by zooplankton to sounds produced by the seismic survey 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. Impacts on zooplankton behavior are 
predicted to be inconsequential. Thus, feeding mysticetes would not be 
adversely affected by this minimal loss or scattering, if any, of 
reduced zooplankton abundance.
    Based on the preceding discussion, the proposed activity is not 
expected to have any habitat-related effects that could cause 
significant or long-term consequences for individual marine mammals or 
their populations.

Proposed Mitigation

    In order to issue an incidental take authorization (ITA) under 
section 101(a)(5)(D) of the MMPA, NMFS must set forth the permissible 
methods of taking pursuant to such activity, and

[[Page 21368]]

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). 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).

Mitigation Measures Proposed by BP

    For the proposed mitigation measures, BP proposed general 
mitigation measures that apply to all vessels involved in the survey 
and specific mitigation measures that apply to the source vessels 
operating airguns. The proposed protocols are discussed next and can 
also be found in Section 11 of BP's application (see ADDRESSES).
1. General Mitigation Measures
    These general mitigation measures are proposed to apply to all 
vessels that are part of the Prudhoe Bay seismic survey, including crew 
transfer vessels. The two source vessels would also operate under an 
additional set of specific mitigation measures during airgun operations 
(described a bit later in this document).
    The general mitigation measures include: (1) adjusting speed to 
avoid collisions with whales and during periods of low visibility; (2) 
checking the waters immediately adjacent to vessels with propellers to 
ensure that no marine mammals will be injured; (3) avoiding 
concentrations of groups of whales and not operating vessels in a way 
that separates members of a group; (4) reducing vessel speeds to less 
than 10 knots in the presence of feeding whales; (5) reducing speed and 
steering around groups of whales if circumstances allow (but never 
cutting off a whale's travel path) and avoiding multiple changes in 
direction and speed when within 900 ft of whales; (6) maintaining an 
altitude of at least 1,000 ft when flying helicopters, except in 
emergency situations or during take-offs and landings; and (7) not 
hovering or circling with helicopters above or within 0.3 mi of groups 
of whales.
2. Seismic Airgun Mitigation Measures
    BP proposes to establish and monitor Level A harassment exclusion 
zones for all marine mammal species. These zones will be monitored by 
PSOs (more detail later). Should marine mammals enter these exclusion 
zones, the PSOs will call for and implement the suite of mitigation 
measures described next.
    Ramp-up Procedure: Ramp-up procedures of an airgun array involve a 
step-wise increase in the number of operating airguns until the 
required discharge volume is achieved. The purpose of a ramp-up 
(sometimes referred to as ``soft-start'') is to provide marine mammals 
in the vicinity of the activity the opportunity to leave the area and 
to avoid the potential for injury or impairment of their hearing 
abilities.
    During ramp-up, BP proposes to implement the common procedure of 
doubling the number of operating airguns at 5-minute intervals, 
starting with the smallest gun in the array. For the 620 in\3\ sub-
array this is estimated to take approximately 15 minutes and for the 
1,240 in\3\ airgun array approximately 20 minutes. During ramp-up, the 
exclusion zone for the full airgun array will be observed. The ramp-up 
procedures will be applied as follows:
    1. A ramp-up, following a cold start, can be applied if the 
exclusion zone has been free of marine mammals for a consecutive 30-
minute period. The entire exclusion zone must have been visible during 
these 30 minutes. If the entire exclusion zone is not visible, then 
ramp-up from a cold start cannot begin.
    2. Ramp-up procedures from a cold start will be delayed if a marine 
mammal is sighted within the exclusion zone during the 30-minute period 
prior to the ramp-up. The delay will last until the marine mammal(s) 
has been observed to leave the exclusion zone or until the animal(s) is 
not sighted for at least 15 minutes (seals) or 30 minutes (cetaceans).
    3. A ramp-up, following a shutdown, can be applied if the marine 
mammal(s) for which the shutdown occurred has been observed to leave 
the exclusion zone or until the animal(s) has not been sighted for at 
least 15 minutes (seals) or 30 minutes (cetaceans). This assumes there 
was a continuous observation effort prior to the shutdown and the 
entire exclusion zone is visible.
    4. If, for any reason, power to the airgun array has been 
discontinued for a period of 10 minutes or more, ramp-up procedures 
need to be implemented. Only if the PSO watch has been suspended, a 30-
minute clearance of the exclusion zone is required prior to commencing 
ramp-up. Discontinuation of airgun activity for less than 10 minutes 
does not require a ramp-up.
    5. The seismic operator and PSOs will maintain records of the times 
when ramp-ups start and when the airgun arrays reach full power.
    Power Down Procedure: A power down is the immediate reduction in 
the number of operating airguns such that the radii of the 190 dB and 
180 dB (rms) zones are decreased to the extent that an observed marine 
mammal is not in the applicable exclusion zone of the full array. 
During a power down, one airgun (or some other number of airguns less 
than the full airgun array) continues firing. The continued operation 
of one airgun is intended to (a) alert marine mammals to the presence 
of airgun activity, and (b) retain the option of initiating a ramp up 
to full operations under poor visibility conditions.
    1. The array will be immediately powered down whenever a marine 
mammal is sighted approaching close to or within the applicable 
exclusion zone of the full array, but is outside the applicable 
exclusion zone of the single mitigation airgun;
    2. Likewise, if a mammal is already within the exclusion zone when 
first detected, the airguns will be powered down immediately;
    3. If a marine mammal is sighted within or about to enter the 
applicable exclusion zone of the single mitigation airgun, it too will 
be shut down; and
    4. Following a power down, ramp-up to the full airgun array will 
not resume until the marine mammal has cleared the applicable exclusion 
zone. The animal will be considered to have cleared the exclusion zone 
if it has been visually observed leaving the exclusion zone of the full 
array, or has not been seen within the zone for 15 minutes (seals) or 
30 minutes (cetaceans).
    Shut-down Procedures: The operating airgun(s) will be shut down 
completely if a marine mammal approaches or enters the 190 or 180 dB 
(rms) exclusion radius of the smallest airgun. Airgun activity will not 
resume until the marine mammal has cleared the applicable exclusion 
radius of the full array. The animal will be considered to have cleared 
the exclusion radius as described above under ramp-up procedures.
    Poor Visibility Conditions: BP plans to conduct 24-hr operations. 
PSOs will not be on duty during ongoing seismic operations during 
darkness, given the very limited effectiveness of visual observation at 
night (there will be no periods of darkness in the survey area until 
mid-August). The proposed provisions associated with operations at 
night or in periods of poor visibility include the following:
     If during foggy conditions, heavy snow or rain, or 
darkness (which may be encountered starting in late August), the full 
180 dB exclusion zone is not visible, the airguns cannot commence a 
ramp-up procedure from a full shut-down; and
     If one or more airguns have been operational before 
nightfall or before the

[[Page 21369]]

onset of poor visibility conditions, they can remain operational 
throughout the night or poor visibility conditions. In this case ramp-
up procedures can be initiated, even though the exclusion zone may not 
be visible, on the assumption that marine mammals will be alerted by 
the sounds from the single airgun and have moved away.
    BP is aware that available techniques to effectively detect marine 
mammals during limited visibility conditions (darkness, fog, snow, and 
rain) are in need of development and has in recent years supported 
research and field trials intended to improve methods of detecting 
marine mammals under these conditions. BP intends to continue research 
and field trials to improve methods of detecting marine mammals during 
periods of low visibility.

Additional Mitigation Measures Proposed by NMFS

    The mitigation airgun will be operated at approximately one shot 
per minute and will not be operated for longer than three hours in 
duration during daylight hours and good visibility. In cases when the 
next start-up after the turn is expected to be during lowlight or low 
visibility, use of the mitigation airgun may be initiated 30 minutes 
before darkness or low visibility conditions occur and may be operated 
until the start of the next seismic acquisition line. The mitigation 
gun must still be operated at approximately one shot per minute.

Mitigation Conclusions

    NMFS has carefully evaluated BP's proposed mitigation measures and 
considered a range of other measures in the context of ensuring that 
NMFS prescribes the means of effecting the least practicable impact on 
the affected marine mammal species and stocks and their habitat. Our 
evaluation of potential measures included consideration of the 
following factors in relation to one another:
     The manner in which, and the degree to which, the 
successful implementation of the measures are 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.
    Any mitigation measure(s) prescribed by NMFS should be able to 
accomplish, have a reasonable likelihood of accomplishing (based on 
current science), or contribute to the accomplishment of one or more of 
the general goals listed below:
    1. Avoidance or minimization of injury or death of marine mammals 
wherever possible (goals 2, 3, and 4 may contribute to this goal).
    2. A reduction in the numbers of marine mammals (total number or 
number at biologically important time or location) exposed to received 
levels of seismic airguns, or other activities expected to result in 
the take of marine mammals (this goal may contribute to 1, above, or to 
reducing harassment takes only).
    3. A reduction in the number of times (total number or number at 
biologically important time or location) individuals would be exposed 
to received levels of seismic airguns or other activities expected to 
result in the take of marine mammals (this goal may contribute to 1, 
above, or to reducing harassment takes only).
    4. A reduction in the intensity of exposures (either total number 
or number at biologically important time or location) to received 
levels of seismic airguns or other activities expected to result in the 
take of marine mammals (this goal may contribute to 1, above, or to 
reducing the severity of harassment takes only).
    5. Avoidance or minimization of adverse effects to marine mammal 
habitat, paying special attention to the food base, activities that 
block or limit passage to or from biologically important areas, 
permanent destruction of habitat, or temporary destruction/disturbance 
of habitat during a biologically important time.
    6. For monitoring directly related to mitigation--an increase in 
the probability of detecting marine mammals, thus allowing for more 
effective implementation of the mitigation.
    Based on our evaluation of the applicant's proposed measures, as 
well as other measures considered by NMFS, NMFS has preliminarily 
determined that the proposed mitigation measures provide the means of 
effecting the least practicable impact on marine mammals species or 
stocks and their habitat, paying particular attention to rookeries, 
mating grounds, and areas of similar significance. Proposed measures to 
ensure availability of such species or stock for taking for certain 
subsistence uses are discussed later in this document (see ``Impact on 
Availability of Affected Species or Stock for Taking for Subsistence 
Uses'' section).

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 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. BP 
submitted information regarding marine mammal monitoring to be 
conducted during seismic operations as part of the IHA application. 
That information can be found in Sections 11 and 13 of the application. 
The monitoring measures may be modified or supplemented based on 
comments or new information received from the public during the public 
comment period.
    Monitoring measures proposed by the applicant or prescribed by NMFS 
should accomplish one or more of the following top-level goals:
    1. An increase in our understanding of the likely occurrence of 
marine mammal species in the vicinity of the action, i.e., presence, 
abundance, distribution, and/or density of species.
    2. An increase in our understanding of the nature, scope, or 
context of the likely exposure of marine mammal species to any of the 
potential stressor(s) associated with the action (e.g. sound or visual 
stimuli), through better understanding of one or more of the following: 
the action itself and its environment (e.g. sound source 
characterization, propagation, and ambient noise levels); the affected 
species (e.g. life history or dive pattern); the likely co-occurrence 
of marine mammal species with the action (in whole or part) associated 
with specific adverse effects; and/or the likely biological or 
behavioral context of exposure to the stressor for the marine mammal 
(e.g. age class of exposed animals or known pupping, calving or feeding 
areas).
    3. An increase in our understanding of how individual marine 
mammals respond (behaviorally or physiologically) to the specific 
stressors associated with the action (in specific contexts, where 
possible, e.g., at what distance or received level).
    4. An increase in our understanding of how anticipated individual 
responses, to individual stressors or anticipated combinations of 
stressors, may impact either: the long-term fitness and survival of an 
individual; or the population, species, or stock (e.g. through effects 
on annual rates of recruitment or survival).

[[Page 21370]]

    5. An increase in our understanding of how the activity affects 
marine mammal habitat, such as through effects on prey sources or 
acoustic habitat (e.g., through characterization of longer-term 
contributions of multiple sound sources to rising ambient noise levels 
and assessment of the potential chronic effects on marine mammals).
    6. An increase in understanding of the impacts of the activity on 
marine mammals in combination with the impacts of other anthropogenic 
activities or natural factors occurring in the region.
    7. An increase in our understanding of the effectiveness of 
mitigation and monitoring measures.
    8. An increase in the probability of detecting marine mammals 
(through improved technology or methodology), both specifically within 
the safety zone (thus allowing for more effective implementation of the 
mitigation) and in general, to better achieve the above goals.

Proposed Monitoring Measures

1. Visual Monitoring
    Two observers referred to as PSOs will be present on each seismic 
source vessel. Of these two PSOs, one will be on watch at all times to 
monitor the 190 and 180 dB exclusion zones for the presence of marine 
mammals during airgun operations. The main objectives of the vessel-
based marine mammal monitoring are as follows: (1) To implement 
mitigation measures during seismic operations (e.g. course alteration, 
airgun power down, shut-down and ramp-up); and (2) To record all marine 
mammal data needed to estimate the number of marine mammals potentially 
affected, which must be reported to NMFS within 90 days after the 
survey.
    BP intends to work with experienced PSOs. At least one Alaska 
Native resident, who is knowledgeable about Arctic marine mammals and 
the subsistence hunt, is expected to be included as one of the team 
members aboard the vessels. Before the start of the seismic survey, the 
crew of the seismic source vessels will be briefed on the function of 
the PSOs, their monitoring protocol, and mitigation measures to be 
implemented.
    On all source vessels, at least one observer will monitor for 
marine mammals at any time during daylight hours (there will be no 
periods of total darkness until mid-August). PSOs will be on duty in 
shifts of a maximum of 4 hours at a time, although the exact shift 
schedule will be established by the lead PSO in consultation with the 
other PSOs.
    The source vessels will offer suitable platforms for marine mammal 
observations. Observations will be made from locations where PSOs have 
the best view around the vessel. During daytime, the PSO(s) will scan 
the area around the vessel systematically with reticle binoculars and 
with the naked eye. Because the main purpose of the PSO on board the 
vessel is detecting marine mammals for the implementation of mitigation 
measures according to specific guidelines, BP prefers to keep the 
information to be recorded as concise as possible, allowing the PSO to 
focus on detecting marine mammals. The following information will be 
collected by the PSOs:
     Environmental conditions--consisting of sea state (in 
Beaufort Wind force scale according to NOAA), visibility (in km, with 
10 km indicating the horizon on a clear day), and sun glare (position 
and severity). These will be recorded at the start of each shift, 
whenever there is an obvious change in one or more of the environmental 
variables, and whenever the observer changes shifts;
     Project activity--consisting of airgun operations (on or 
off), number of active guns, line number. This will be recorded at the 
start of each shift, whenever there is an obvious change in project 
activity, and whenever the observer changes shifts; and
     Sighting information--consisting of the species (if 
determinable), group size, position and heading relative to the vessel, 
behavior, movement, and distance relative to the vessel (initial and 
closest approach). These will be recorded upon sighting a marine mammal 
or group of animals.
    When marine mammals in the water are detected within or about to 
enter the designated exclusion zones, the airgun(s) power down or shut-
down procedures will be implemented immediately. To assure prompt 
implementation of power downs and shut-downs, multiple channels of 
communication between the PSOs and the airgun technicians will be 
established. During the power down and shut-down, the PSO(s) will 
continue to maintain watch to determine when the animal(s) are outside 
the exclusion radius. Airgun operations can be resumed with a ramp-up 
procedure (depending on the extent of the power down) if the observers 
have visually confirmed that the animal(s) moved outside the exclusion 
zone, or if the animal(s) were not observed within the exclusion zone 
for 15 minutes (seals) or for 30 minutes (cetaceans). Direct 
communication with the airgun operator will be maintained throughout 
these procedures.
    All marine mammal observations and any airgun power down, shut-
down, and ramp-up will be recorded in a standardized format. Data will 
be entered into or transferred to a custom database. The accuracy of 
the data entry will be verified daily through QA/QC procedures. 
Recording procedures will allow initial summaries of data to be 
prepared during and shortly after the field program, and will 
facilitate transfer of the data to other programs for further 
processing and archiving.
2. Fish and Airgun Sound Monitoring
    BP proposes to conduct research on fish species in relation to 
airgun operations, including prey species important to ice seals, 
during the proposed seismic survey. The North Prudhoe Bay OBS seismic 
survey offers a unique opportunity to assess the impacts of airgun 
sounds on fish, specifically on changes in fish abundance in fyke nets 
that have been sampled in the area for more than 30 years. The 
monitoring study would occur over a 2-month period during the open-
water season. During this time, fish are counted and sized every day, 
unless sampling is prevented by weather, the presence of bears, or 
other events. Fish mortality is also noted.
    The fish-sampling period coincides with the North Prudhoe seismic 
survey, resulting in a situation where each of the four fyke nets will 
be exposed to varying daily exposures to airgun sounds. That is, as 
source vessels move back and forth across the project area, fish caught 
in nets will be exposed to different sounds levels at different nets 
each day. To document relationships between fish catch in each fyke net 
and received sound levels, BP will attempt to instrument each fyke net 
location with a recording hydrophone. Recording hydrophones, to the 
extent possible, will have a dynamic range that extends low enough to 
record near ambient sounds and high enough to capture sound levels 
during relatively close approaches by the airgun array (i.e., likely 
levels as high as about 200 dB re 1 uPa). Bandwidth will extend from 
about 10 Hz to at least 500 Hz. In addition, because some fish 
(especially salmonids) are likely to be sensitive to particle velocity 
instead of or in addition to sound pressure level, BP will attempt to 
instrument each fyke net location with a recording particle velocity 
meter. Acoustic and environmental data will be used in statistical 
models to assess relationships

[[Page 21371]]

between acoustic and fish variables. Additional information on the 
details of the fish monitoring study can be found in Section 13.1 of 
BP'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 BP's Prudhoe Bay OBS Seismic Survey Monitoring 
Plan. The panel met on January 8-9, 2013, and provided their final 
report to NMFS on February 25, 2013. The full panel report can be 
viewed on the Internet at: http://www.nmfs.noaa.gov/pr/pdfs/permits/openwater/bp_panel2013.pdf.
    NMFS provided the panel with BP's monitoring plan and asked the 
panel to answer the following questions regarding the plan:
    1. Will the applicant's stated objectives effectively further the 
understanding of the impacts of their activities on marine mammals and 
otherwise accomplish the goals stated above? If not, how should the 
objectives be modified to better accomplish the goals above?
    2. Can the applicant achieve the stated objectives based on the 
methods described in the plan?
    3. Are there technical modifications to the proposed monitoring 
techniques and methodologies proposed by the applicant that should be 
considered to better accomplish their stated objectives?
    4. Are there techniques not proposed by the applicant (i.e., 
additional monitoring techniques or methodologies) that should be 
considered for inclusion in the applicant's monitoring program to 
better accomplish their stated objectives?
    5. What is the best way for an applicant to present their data and 
results (formatting, metrics, graphics, etc.) in the required reports 
that are to be submitted to NMFS (i.e., 90-day report and comprehensive 
report)?
    NMFS shared the panel's report with BP in March 2013. BP originally 
submitted this IHA application with a monitoring plan to conduct this 
program during the 2013 open-water season; however, after undergoing 
peer review of the monitoring plan in early 2013, BP subsequently 
cancelled the 2013 operation. The proposed 2014 program is the same as 
that reviewed by the panel in 2013. BP reviewed the 2013 panel 
recommendation report and incorporated several of the panel's 
recommendations into the monitoring plan contained in the 2014 
application. NMFS reviewed the panel's report and agrees with the 
recommendations included in BP's 2014 monitoring plan. A summary of the 
measures that were included is provided next.
    Based on the panel report, NMFS recommends and BP proposes to 
follow a pre-determined regime for scanning of the area by PSOs that is 
based on the relative importance of detecting marine mammals in the 
near- and far fields. PSOs should simply record the primary behavioral 
state (i.e., traveling, socializing, feeding, resting, approaching or 
moving away from vessels) and relative location of the observed marine 
mammals and not try to precisely determine the behavior or the context.
    Other recommendations made by panel members that NMFS supports and 
propose BP include in the monitoring plan include: (1) recording 
observations of pinnipeds on land and not just in the water; (2) 
developing a means by which PSOs record data with as little impact on 
observation time as possible; (3) continuing PSO observation watches 
when there is an extended period when no airguns on any of the source 
vessels are operating to collect additional observation data during 
periods of non-seismic; and (4) accounting for factors such as water 
depth when estimating the actual level of takes because of the 
difficulties in monitoring during darkness or inclement weather. 
Moreover, the panel recommended and NMFS agrees that BP should be very 
clear in the 90-day technical report about what periods are considered 
``seismic'' and ``non-seismic'' for their analyses.
    As recommended by the panel, NMFS encourages BP to examine data 
from ASAMM and other such programs to assess possible impacts from 
their seismic surveys. As noted earlier in this document, BP has 
proposed a fish and airgun sound monitoring study, which has been well 
received by past panel members. This study will also allow BP to 
collect sound signature data on equipment used during this proposed 
survey.
    The panel also recommended that BP work to understand the 
cumulative nature of the activity and sound footprint. As described in 
Section 14 of the IHA application, BP remains committed to working with 
a wide range of experts to improve understanding of the cumulative 
effects of multiple sound sources and has sponsored an expert working 
group on the issue.

Reporting Measures

1. 90-Day Technical Report
    A report will be submitted to NMFS within 90 days after the end of 
the proposed seismic survey. The report will summarize all activities 
and monitoring results conducted during in-water seismic surveys. The 
Technical Report will include the following:
     Summary of project start and end dates, airgun activity, 
number of guns, and the number and circumstances of implementing ramp-
up, power down, shutdown, and other mitigation actions;
     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);
     Analyses of the effects of various factors influencing 
detectability of marine mammals (e.g., sea state, number of observers, 
and fog/glare);
     Species composition, occurrence, and distribution of 
marine mammal sightings, including date, water depth, numbers, age/
size/gender categories (if determinable), and group sizes;
     Analyses of the effects of survey operations;
     Sighting rates of marine mammals during periods with and 
without seismic survey activities (and other variables that could 
affect detectability), such as: (i) Initial sighting distances versus 
survey activity state; (ii) closest point of approach versus survey 
activity state; (iii) observed behaviors and types of movements versus 
survey activity state; (iv) numbers of sightings/individuals seen 
versus survey activity state; (v) distribution around the source 
vessels versus survey activity state; and (vi) estimates of exposures 
of marine mammals to Level B harassment thresholds based on presence in 
the 160 dB harassment zone.
2. Fish and Airgun Sound Report
    BP proposes to present the results of the fish and airgun sound 
study to NMFS in a detailed report that will also be submitted to a 
peer reviewed journal

[[Page 21372]]

for publication, presented at a scientific conference, and presented in 
Barrow and Nuiqsut.
3. Notification of Injured or Dead Marine Mammals
    In the unanticipated event that the specified activity clearly 
causes the take of a marine mammal in a manner prohibited by the IHA 
(if issued), such as an injury (Level A harassment), serious injury or 
mortality (e.g., ship-strike, gear interaction, and/or entanglement), 
BP would immediately cease the specified activities and immediately 
report the incident to the Chief of the Permits and Conservation 
Division, Office of Protected Resources, NMFS, and the Alaska Regional 
Stranding Coordinators. The report would include the following 
information:
     Time, date, and location (latitude/longitude) of the 
incident;
     Name and type of vessel involved;
     Vessel's speed during and leading up to the incident;
     Description of the incident;
     Status of all sound source use in the 24 hours preceding 
the incident;
     Water depth;
     Environmental conditions (e.g., wind speed and direction, 
Beaufort sea state, cloud cover, and visibility);
     Description of all marine mammal observations in the 24 
hours preceding the incident;
     Species identification or description of the animal(s) 
involved;
     Fate of the animal(s); and
     Photographs or video footage of the animal(s) (if 
equipment is available).
    Activities would not resume until NMFS is able to review the 
circumstances of the prohibited take. NMFS would work with BP to 
determine what is necessary to minimize the likelihood of further 
prohibited take and ensure MMPA compliance. BP would not be able to 
resume their activities until notified by NMFS via letter, email, or 
telephone.
    In the event that BP 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), BP 
would immediately report the incident to the Chief of the Permits and 
Conservation Division, Office of Protected Resources, NMFS, and the 
NMFS Alaska Stranding Hotline and/or by email to the Alaska Regional 
Stranding Coordinators. The report would include the same information 
identified in the paragraph above. Activities would be able to continue 
while NMFS reviews the circumstances of the incident. NMFS would work 
with BP to determine whether modifications in the activities are 
appropriate.
    In the event that BP 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 the IHA (e.g., 
previously wounded animal, carcass with moderate to advanced 
decomposition, or scavenger damage), BP would report the incident to 
the Chief of the Permits and Conservation Division, Office of Protected 
Resources, NMFS, and the NMFS Alaska Stranding Hotline and/or by email 
to the Alaska Regional Stranding Coordinators, within 24 hours of the 
discovery. BP would provide photographs or video footage (if available) 
or other documentation of the stranded animal sighting to NMFS and the 
Marine Mammal Stranding Network.

Monitoring Results From Previously Authorized Activities

    BP has not requested and NMFS has not issued an IHA for this 
project previously. However, in 2012, BP conducted (and NMFS issued an 
IHA for) a similar seismic survey (known as an ocean bottom cable [OBC] 
survey) in the Simpson Lagoon area of the Beaufort Sea, Alaska, which 
is less than 50 mi west of Prudhoe Bay. Seismic acquisition for that 
survey occurred from July 29 through September 7, 2012. Three source 
vessels were used and operated in a flip-flop mode, which is the mode 
proposed for this Prudhoe Bay survey.
    During the 2012 Simpson Lagoon seismic survey, BP employed PSOs to 
watch for marine mammals on all three source vessels. Over the course 
of the survey, PSOs observed for a total of 1,239 on-watch hours during 
daylight hours and for 247 on-watch hours during darkness or limited 
visibility hours. On-watch means the vessel was active (transiting, 
line shooting, off-line shooting). There were no periods of darkness 
for the first 2.5 weeks of the survey. The number of hours of darkness 
began to gradually increase beginning in mid-August with up to 8 hours 
of darkness on September 7, the last day of the survey. PSOs did not 
detect any cetaceans during the seismic survey. An estimated 47 
pinnipeds were seen in 45 sightings within the seismic survey area from 
July 29 to September 7 from the three seismic source vessels. Sightings 
were of ringed, bearded, and spotted seals, as well as some recorded as 
unidentified seal or pinniped. Most pinnipeds were observed looking at 
the vessel, and a few swam away or dove after the initial sighting.
    During the 2012 Simpson Lagoon OBC seismic survey, a total of five 
shut-downs (11 percent of sightings), three power-downs (7 percent of 
sightings), and five delayed ramp-ups (11 percent of sightings) 
occurred for pinnipeds. A delayed ramp-up occurred when a marine mammal 
was observed during the 30-min clearance period. If ramp-up was 
initiated (i.e., at least one airgun was operational) when a marine 
mammal was sighted, reducing the number of airguns was considered a 
power-down (one 40 in\3\ airgun) or shut-down (no airguns were 
operational). Given the small size of the bridge on all source vessels, 
PSOs, gunners, and captains were in constant communication, and all PSO 
mitigation requests were implemented as soon as possible (within 
seconds). Four of the five shut-downs occurred when an animal was 
sighted at distances of 50 m, 50 m, 75 m and 150 m from the seismic 
source. The remaining shut-down occurred for an animal that was sighted 
at a distance of 500 m from the seismic source; while this was outside 
of the 190-dB exclusion zone, the animal was headed toward the 
exclusion zone. All three power-downs occurred when an animal was 
observed approaching the exclusion zone. More detail can be found in 
BP's final 90-day technical report on the Internet at: http://www.nmfs.noaa.gov/pr/pdfs/permits/bp_openwater_90dayreport.pdf.
    Based on the information contained in BP's 90-day technical report 
of the 2012 Simpson Lagoon OBC seismic survey, BP complied with all 
mitigation and monitoring requirements in the IHA. The amount of 
estimated take did not exceed that analyzed for the IHA.

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 of some species is anticipated as a result of the proposed 
OBS seismic survey. Anticipated impacts to marine mammals are 
associated with noise propagation from the sound sources (e.g., airguns 
and pingers) used in the seismic survey. No take is expected to result 
from vessel

[[Page 21373]]

strikes because of the slow speed of the vessels (1-5 knots while 
acquiring seismic data) and because of mitigation measures to reduce 
collisions with marine mammals. Additionally, no take is expected to 
result from helicopter operations because of altitude restrictions.
    BP requested take of 11 marine mammal species by Level B 
harassment. However, for reasons mentioned earlier in this document, it 
is highly unlikely that humpback and minke whales would occur in the 
proposed seismic survey area. Therefore, NMFS does not propose to 
authorize take of these two species. The species for which take, by 
Level B harassment only, is proposed include: Bowhead, beluga, gray, 
and killer whales; harbor porpoise; and ringed, bearded, spotted, and 
ribbon seals.
    The airguns produce impulsive sounds. The current acoustic 
thresholds used by NMFS to estimate Level B and Level A harassment are 
presented in Table 4.

        Table 4--Current Acoustic Exposure Criteria Used by NMFS
------------------------------------------------------------------------
           Criterion             Criterion definition       Threshold
------------------------------------------------------------------------
Level A Harassment (Injury)...  Permanent Threshold     180 dB re 1
                                 Shift (PTS) (Any        microPa-m
                                 level above that        (cetaceans)/190
                                 which is known to       dB re 1 microPa-
                                 cause TTS).             m (pinnipeds)
                                                         root mean
                                                         square (rms).
Level B Harassment............  Behavioral Disruption   160 dB re 1
                                 (for impulse noises).   microPa-m
                                                         (rms).
Level B Harassment............  Behavioral Disruption   120 dB re 1
                                 (for continuous,        microPa-m
                                 noise).                 (rms).
------------------------------------------------------------------------

    Section 6 of BP's application contains a description of the 
methodology used by BP to estimate takes by harassment, including 
calculations for the 160 dB (rms) isopleth and marine mammal densities 
in the areas of operation (see ADDRESSES), which is also provided in 
the following sections. NMFS verified BP's methods, and used the 
density and sound isopleth measurements in estimating take. However, as 
noted later in this section, NMFS proposes to authorize the maximum 
number of estimated takes for all species, not just for cetaceans as 
presented by BP in order to ensure that exposure estimates are not 
underestimated for pinnipeds.
    During data acquisition, the source vessels of the proposed OBS 
Prudhoe Bay seismic survey will cover an area of about 190 mi\2\ in 
water depths ranging from 3 to 50 ft. Seismic data acquisition will be 
halted at the start of the Cross Island fall bowhead whale hunt. The 
total duration of seismic data acquisition in the Prudhoe Bay area is 
estimated to be approximately 45 days. About 25% of downtime is 
included in this total, so the actual number of days that airguns are 
expected to be operating is about 34, based on a continuous 24-hr 
operation.

Marine Mammal Density Estimates

    Most whale species are migratory and therefore show a seasonal 
distribution, with different densities for the summer period (covering 
July and August) and the fall period (covering September and October). 
Seal species in the Beaufort Sea do not show a distinct seasonal 
distribution during the open-water period between July and October. 
Data acquisition of the proposed seismic survey will only take place in 
summer (before start of Nuiqsut whaling in late August/early 
September), so BP estimated only summer densities for this proposed 
IHA. Whale and seal densities in the Beaufort Sea will further depend 
on the presence of sea ice. However, if ice cover within or close to 
the seismic survey area is more than approximately 10%, seismic survey 
activities may not start or will be halted. Densities related to ice 
conditions are therefore not included in the IHA application.
    Spatial differentiation is another important factor for marine 
mammal densities, both in latitudinal and longitudinal gradient. Taking 
into account the shallow water operations of the proposed seismic 
survey area and the associated area of influence, BP used data from the 
nearshore zone of the Beaufort Sea for the calculation of densities, if 
available.
    Density estimates are based on best available data. Because 
available data did not always cover the area of interest, this is 
subject to large temporal and spatial variation, and correction factors 
for perception and availability bias were not always known, there is 
some uncertainty in the data and assumptions used in the estimated 
number of exposures. To provide allowance for these uncertainties, 
maximum density estimates have been provided in addition to average 
density estimates.
1. Beluga Whale Density Estimates
    The 1979-2011 BWASP aerial survey database, available from the NOAA 
Web site (http://www.afsc.noaa.gov/NMML/software/bwasp-comida.php), 
contains a total of 62 belugas (31 sightings) in block 1, which covers 
the nearshore and offshore Prudhoe Bay area. Except for one solitary 
animal in 1992, all these belugas were seen in September or October; 
the months with most aerial survey effort. None of the sightings 
occurred south of 70[deg] N., which is to be expected because beluga 
whales generally travel much farther north (Moore et al., 2000). The 
summer effort in the 1979-2011 database is limited. Therefore, BP 
considered and NMFS agreed that the 2012-2013 data to be the best 
available data for calculating beluga summer densities (Clarke et al., 
2013; http://www.asfc.noaa.gov/nmml/cetacean/bwasp/2013), even though 
the 2013 daily flight summaries posted on NOAA's Web site have not 
undergone post-season QA/QC.
    To estimate the density of beluga whales in the Prudhoe Bay area, 
BP used the 2012 on-transect beluga sighting and effort data from the 
ASAMM surveys flown in July and August in the Beaufort Sea. The area 
most applicable to our survey was the area from 140[deg] W.-154[deg] W. 
and water depths of 0-20 m (Table 13 in Clarke et al., 2013). In 
addition, BP used beluga sighting and effort data of the 2013 survey, 
as reported in the daily flight summaries on the NOAA Web site. BP 
intended to only select flights that covered block 1. However, in many 
cases the aerial surveys flown in block 1 also covered blocks 2 and 10, 
which were much farther from shore. Because it was difficult to 
determine the survey effort specific to block 1 from the available 
information, BP included the sighting and effort data from block 2 and 
10 in the calculations. BP used the number of individuals counted on 
transect, together with the transect kilometers flown, to calculate 
density estimates (Table 4 in the application and Table 5 here). To 
convert the number of individuals per transect kilometer (ind/km) to a 
density per area (ind/km\2\), BP used the effective strip width (ESW) 
of 0.614 km for belugas calculated from 2008-2012 aerial survey

[[Page 21374]]

data flown with the Commander aircraft (M. Ferguson, NMML, pers. comm., 
30 Oct 2013).
[GRAPHIC] [TIFF OMITTED] TN15AP14.001

2. Bowhead Whale Density Estimates
    To estimate summer bowhead whale densities, BP used data from the 
2012 and 2013 ASAMM aerial surveys flown in the Beaufort Sea (Clarke et 
al., 2013; www.asfc.noaa.gov/nmml/). The 1979-2011 ASAMM database 
contains only one on-transect bowhead whale sighting during July and 
August (in 2011), likely due to the limited summer survey effort. In 
contrast, the 2012 and 2013 surveys include substantial effort during 
the summer season and are thus considered to be the best available 
data, even though the 2013 daily flight summaries posted on NOAA's Web 
site have not undergone post-season QA/QC.
    To estimate the density of bowhead whales in the Prudhoe Bay area, 
BP used the 2012 on-transect bowhead sighting and effort data from 
surveys flown in July and August in block 1 (Table 4 in Clarke et al., 
2013). In addition, BP used the on-transect bowhead sighting and effort 
data of the 2013 survey, as reported in the daily flight summaries on 
the NOAA Web site. BP intended to only select flights that covered 
block 1. However, in many cases the aerial surveys flown in block 1 
also covered blocks 2 and 10, which were much farther from shore. 
Because it was difficult to determine the survey effort specific to 
block 1 from the available information, BP included the sighting and 
effort data from block 2 and 10 in the calculations (Table 5 in the 
application and Table 6 here). To convert the number of individuals per 
line transect (ind/km) to a density per area (ind/km2), BP used the ESW 
of 1.15 km for bowheads, calculated from 2008-2012 aerial survey data 
flown with the Commander aircraft (M. Ferguson, NMML, pers. comm., 30 
Oct 2013).
[GRAPHIC] [TIFF OMITTED] TN15AP14.002

3. Other Whale Species
    No densities have been estimated for gray whales and for whale 
species that are rare or extralimital to the Beaufort Sea (killer whale 
and harbor porpoise) because sightings of these animals have been very 
infrequent. Gray whales may be encountered in small numbers throughout 
the summer and fall, especially in the nearshore areas. Small numbers 
of harbor porpoises may be encountered as well. During an aerial survey 
offshore of Oliktok Point in 2008, approximately 40 mi (65 km) west of 
the proposed survey area, two harbor porpoises were sighted offshore of 
the barrier islands, one on 25 August and the other on 10 September 
(Hauser et al., 2008). For the purpose of this IHA request, small 
numbers have been included in the requested ``take'' authorization to 
cover incidental occurrences of any of these species during the 
proposed survey.
4. Seal Density Estimates
    Ice seals of the Beaufort Sea are mostly associated with sea ice, 
and most census methods count seals when they are hauled out on the 
ice. To account for the proportion of animals present but not hauled 
out (availability bias) or seals present on the ice but missed 
(detection bias), a correction factor should be applied to the ``raw'' 
counts. This correction factor is dependent on the behavior of each 
species. To estimate what proportion of ringed seals were generally 
visible resting on the sea ice, radio tags were placed on seals during 
spring 1999-2003 (Kelly et al., 2006). The probability that seals were 
visible,

[[Page 21375]]

derived from the satellite data, was applied to seal abundance data 
from past aerial surveys and indicated that the proportion of seals 
visible varied from less than 0.4 to more than 0.75 between survey 
years. The environmental factors that are important in explaining the 
availability of seals to be counted were found to be time of day, date, 
wind speed, air temperature, and days from snow melt (Kelly et al., 
2006). Besides the uncertainty in the correction factor, using counts 
of basking seals from spring surveys to predict seal abundance in the 
open-water period is further complicated by the fact that seal 
movements differ substantially between these two seasons. Data from 
nine ringed seals that were tracked from one subnivean period (early 
winter through mid-May or early June) to the next showed that ringed 
seals covered large distances during the open-water foraging period 
(Kelly et al., 2010b). Ringed seals tagged in 2011 close to Barrow also 
show long distances traveled during the open-water season (Herreman et 
al., 2012).
    To estimate densities for ringed, bearded, and spotted seals, BP 
used data collected during four shallow water OBC seismic surveys in 
the Beaufort Sea (Harris et al., 2001; Aerts et al., 2008; Hauser et 
al., 2008; HDR, 2012). Habitat and survey specifics are very similar to 
the proposed survey; therefore, these data were considered to be more 
representative than basking seal densities from spring aerial survey 
data (e.g., Moulton et al., 2002; Frost et al., 2002, 2004). NMFS 
agreed that these data are likely more representative and appropriate 
for use. However, since these data were not collected during surveys 
designed to determine abundance, NMFS used the maximum estimates for 
the proposed number of takes in this proposed IHA.
    Because survey effort in kilometers was only reported for one of 
the surveys, BP used sighting rate (ind/h) for calculating potential 
seal exposures. No distinction is made in seal density between summer 
and autumn season. Also, no correction factors have been applied to the 
reported seal sighting rates.
    Seal species ratios: During the 1996 OBC survey, 92% of all seal 
species identified were ringed seals, 7% bearded seals and 1% spotted 
seals (Harris et al., 2001). This 1996 survey occurred in two habitats, 
one about 19 mi east of Prudhoe Bay near the McClure Islands, mainly 
inshore of the barrier islands in water depths of 10 to 26 ft and the 
other 6 to 30 mi northwest of Prudhoe Bay, about 0 to 8 mile offshore 
of the barrier islands in water depths of 10 to 56 ft (Harris et al., 
2001). In 2008, two OBC seismic surveys occurred in the Beaufort Sea, 
one in Foggy Island Bay, about 15 mi SE of Prudhoe Bay (Aerts et al., 
2008), and the other at Oliktok Point, >30 mi west of Prudhoe Bay 
(Hauser et al., 2008). In 2012, an OBC seismic was done in Simpson 
Lagoon, bordering the area surveyed in 2008 at Oliktok Point (HDR, 
2012). Based on the number of identified individuals the ratio ringed, 
bearded, and spotted seal was 75%, 8%, and 17%, respectively in Foggy 
Island Bay (Aerts et al., 2008), 22%, 39%, and 39%, respectively at 
Oliktok Point (Hauser et al., 2008), and 62%, 15%, and 23%, 
respectively in Simpson Lagoon (HDR, 2012). Because it is often 
difficult to identify seals to species, a large proportion of seal 
sightings were unidentified in all four OBC surveys described here. The 
total seal sighting rate was therefore used to calculate densities for 
each species, using the average ratio over all four surveys for ringed, 
bearded, and spotted seals, i.e., 63% ringed, 17% bearded, and 20% 
spotted seals.
    Seal sighting rates: During the 1996 OBC survey (Harris et al., 
2001) the sighting rate for all seals during periods when airguns were 
not operating was 0.63 ind/h. The sighting rate during non-seismic 
periods was 0.046 ind/h for the survey in Foggy Island Bay, just east 
of Prudhoe Bay (Aerts et al., 2008). The OBC survey that took place at 
Oliktok Point recorded 0.0674 ind/h when airguns were not operating 
(Hauser et al., 2008), and the maximum sighting rate during the Simpson 
Lagoon OBC seismic survey was 0.030 ind/h (HDR, 2012).
    The average seal sighting rate, based on these four surveys, was 
0.193 ind/h. The maximum was 0.63 ind/h and the minimum 0.03 ind/h. 
Using the proportion of ringed, bearded, and spotted seals as mentioned 
above, BP estimated the average and maximum sighting rates (ind/h) for 
each of the three seal species (Table 6 in the application and Table 7 
here).
5. Marine Mammal Density Summary
    For the purpose of calculating the potential number of beluga and 
bowhead whale exposures to received sound levels of >=160 dB re 1 
[mu]Pa, BP used the minimum density from Tables 5 and 6 in this 
document as the average density. The reason for this decision is that 
the 2012 data only covered block 1 and were considered more 
representative. To derive a maximum estimated number of exposures, BP 
used the average densities from Tables 5 and 6 in this document. BP 
considered this approach reasonable because the 2013 beluga and bowhead 
whale sighting data included areas outside the zone of influence of the 
proposed project. For example, in 2013, only 3 of the 89 beluga 
sightings were seen in block 1. Table 7 in this document summarizes the 
densities used in the calculation of potential number of exposures.

[[Page 21376]]

[GRAPHIC] [TIFF OMITTED] TN15AP14.003

Level A and Level B Harassment Zone Distances

    For the proposed 2014 OBS seismic survey, BP used existing sound 
source verification (SSV) measurements to establish distances to 
received sound pressure levels (SPLs). Airgun arrays consist of a 
cluster of independent sources. Because of this, and many other 
factors, sounds generated by these arrays therefore do not propagate 
evenly in all directions. BP included both broadside and endfire 
measurements of the array in calculating distances to the various 
received sound levels. Broadside and endfire measurements are not 
applicable to mitigation gun measurements.
    Five SSV measurements exist of an array consisting of eight airguns 
(totaling to 880 in\3\) in the shallow water environment of the 
Beaufort Sea. All these measurements were from 2008: One in Foggy 
Island Bay and four in Oliktok Point (two source vessels and two water 
depths). There is one measurement of a 16 airgun array (640 in\3\), 
from the 2012 Simpson Lagoon OBC seismic survey along water depths of 
approximately 40-60 ft (outside the barrier islands). Table 7 in BP's 
application shows average, maximum, and minimum measured distances to 
each of the four received SPL rms levels of the 880 in\3\ array and the 
880 and 640 in\3\ arrays combined. BP used the average distance of the 
combined 640-880 in\3\ SSV measurements as the mitigation radii (see 
Table 8 in BP's application). Although the discharge volumes of the 
proposed sub-array (620 in\3\) and combined sub-arrays (1240 in\3\) are 
different than the airgun arrays measured before, the acoustic 
properties are very similar due to the airgun configuration (number of 
guns and sizes). As an example, the rms source level of the eight-gun 
880 in\3\ array and the eight-gun 620 in\3\ arrays are very similar 
(217 and 218 dB re 1 [mu]Pa rms, respectively). Likewise, the rms 
source levels of the 16-gun 640 in\3\ and 1240 in\3\ were comparable 
(223 and 224 dB re 1 [mu]Pa rms, respectively). BP therefore considered 
the distances derived from the existing airgun arrays as summarized in 
Table 7 in BP's application as representative for the proposed 620-1240 
in\3\ arrays. NMFS concurs with this approach.
    Three shallow water SSV measurements were used to calculate the 
average, maximum, and minimum distances for the 40 in\3\ mitigation gun 
(see Table 7 in BP's application). Two measurements were from the 2012 
Simpson lagoon seismic survey (in water depths of approximately 40-60 
ft and 6.5 ft) and one measurement from the 2011 Harrison Bay shallow 
hazard survey in 6.5 ft water depth (from a 4 x 10 in\3\ cluster). BP 
derived the distances for the 10 in\3\ mitigation gun from four shallow 
hazard SSV measurements in the Beaufort Sea: One in 2007, two in 2008, 
and one in 2011.
    Table 8 in this document presents the radii used to estimate take 
(160 dB isopleth) and to implement mitigation measures (180 dB and 190 
dB isopleths) from the full airgun array and the 40 in\3\ and 10 in\3\ 
mitigation guns. However, take is only estimated using the larger 
radius of the full airgun array.

Table 8--Distances (in Meters) To Be Used for Estimating Take by Level B
  Harassment and for Mitigation Purposes During the Proposed 2014 North
                     Prudhoe Bay 2014 Seismic Survey
------------------------------------------------------------------------
                                                190 dB   180 dB   160 dB
       Airgun discharge volume (in\3\)           re 1     re 1     re 1
                                                [mu]Pa   [mu]Pa   [mu]Pa
------------------------------------------------------------------------
620-1240 in\3\...............................      300      600     5000
40 in\3\.....................................       70      200     2000
10 in\3\.....................................       20       50      600
------------------------------------------------------------------------

Numbers of Marine Mammals Potentially Taken by Harassment

    The potential number of marine mammals that might be exposed to the 
160 dB re 1 [mu]Pa (rms) SPL was calculated differently for cetaceans 
and pinnipeds, as described in Section 6.3 of BP's application and next 
here.
1. Number of Cetaceans Potentially Taken by Harassment
    The potential number of bowhead and beluga whales that might be 
exposed to the 160 dB re 1 [mu]Pa (rms) sound pressure level was 
calculated by multiplying:
     The expected bowhead and beluga density as provided in 
Tables 5 and 6 in this document (Tables 4 and 5 in BP's application);
     the anticipated area around each source vessel that is 
ensonified by the 160 dB re 1 [mu]Pa (rms) sound pressure level; and
     the estimated number of 24-hr days that the source vessels 
are operating.
    The area expected to be ensonified by the 620-1,240 in\3\ array was 
determined based on the maximum distance to the 160 dB re 1 [mu]Pa 
(rms) sound pressure level as determined from the maximum 640-880 in\3\ 
array measurements (Table 7 in BP's application and summarized

[[Page 21377]]

in Table 8 in this document), rounded to 5 km. Based on a radius of 5 
km, the 160 dB isopleth used in the exposure calculations was 78.5 
km\2\. It is expected that on average, two source vessels will be 
operating simultaneously, although one source vessel might sometimes be 
engaged in crew change, maintenance, fueling, or other activities that 
do not require the operation of airguns. The minimum distance between 
the two source vessels will be about 550 ft. Although there will be an 
overlap in ensonified area, for the estimated number of exposures, BP 
summed the exposed area of each source vessel. Using the maximum 
distance and summing the isopleths of both source vessels provides a 
likely overestimate of marine mammal exposures.
    The estimated number of 24-hr days of airgun operations was 
determined by assuming a 25% downtime during the 45-day planned data 
acquisition period. Downtime is related to weather, equipment 
maintenance, mitigation implementation, and other circumstances. The 
total number of full 24-hr days that data acquisition is expected to 
occur is approximately 34 days or 816 hours.
    Average and maximum estimates of the number of bowhead and beluga 
whales potentially exposed to sound pressure levels of 160 dB re 1 
[mu]Pa (rms) or more are summarized in Table 9 in BP's application. 
Species such as gray whale, killer whale, and harbor porpoise are not 
expected to be encountered but might be present in very low numbers; 
the maximum expected number of exposures for these species provided in 
Table 9 of BP's application is based on the likelihood of incidental 
occurrences.
    The average and maximum number of bowhead whales potentially 
exposed to sound levels of 160 dB re 1 [mu]Pa (rms) or more is 
estimated at 8 and 29, respectively. BP requested the maximum number of 
expected exposures based on the unexpected large numbers of bowheads 
observed in August during the 2013 ASAMM survey. The average and 
maximum number of potential beluga exposures to 160 dB is 15 and 36, 
respectively. Belugas are known to show aggregate behavior and can 
occur in large numbers in nearshore zones, as evidenced by the sighting 
at Endicott in August 2013. Therefore, for the unlikely event that a 
group of belugas appears within the 160 dB isopleth during the proposed 
seismic survey, BP added a number of 75 to the requested authorization. 
Chance encounters with small numbers of other whale species are 
possible.
    These estimated exposures do not take into account the proposed 
mitigation measures, such as PSOs watching for animals, shutdowns or 
power downs of the airguns when marine mammals are seen within defined 
ranges, and ramp-up of airguns.
2. Number of Pinnipeds Potentially Taken by Harassment
    The estimated number of seals that might be exposed to pulsed 
sounds of 160 dB re 1 [mu]Pa (rms) was calculated by multiplying:
     The expected species specific sighting rate as provided in 
Table 7 in this document (also in Table 6 in BP's application); and
     the total number of hours that each source vessel will be 
operating during the data acquisition period.
    The estimated number of hours that each source vessel will operate 
its airguns was determined by assuming a 25% downtime during a 45-day 
survey period, which is a total of 816 hours (34 days of 24 hour 
operations). It is expected that on average, two source vessels will be 
operating simultaneously. As a comparison, during a similar survey in 
Simpson Lagoon, three source vessels were operating their airguns for a 
total of approximately 710 hrs to cover an area of 110 mi\2\. The 816 
hours of airgun operations for the North Prudhoe survey seems therefore 
a reasonable estimate. The resulting average and maximum number of 
ringed, bearded, and spotted seal exposures based on 816 hours of 
airgun operations are summarized in Table 9 of BP's application. BP 
assumed that all seal sightings would occur within the 160 dB isopleth. 
These estimated exposures do not take into account the proposed 
mitigation measures, such as PSOs watching for animals, shutdowns or 
power downs of the airguns when marine mammals are seen within defined 
ranges, and ramp-up of airguns.

Estimated Take by Harassment Summary

    Table 9 here outlines the density estimates used to estimate Level 
B takes, the proposed Level B harassment take levels, the abundance of 
each species in the Beaufort Sea, the percentage of each species or 
stock estimated to be taken, and current population trends. As 
explained earlier in this document, NMFS used the maximum density 
estimates or sighting rates and proposes to authorize the maximum 
estimates of exposures. Additionally, as explained earlier, density 
estimates are not available for species that are uncommon in the 
proposed seismic survey area.

   Table 9--Density Estimates or Species Sighting Rates, Proposed Level B Harassment Take Levels, Species or Stock Abundance, Percentage of Population
                                                     Proposed To Be Taken, and Species Trend Status
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                Density
                  Species                     (/    Sighting rate  Proposed level     Abundance     Percentage of              Trend
                                                km\2\)         (ind/hr)         B take                        population
--------------------------------------------------------------------------------------------------------------------------------------------------------
Beluga whale..............................          0.0105  ..............              75          39,258            0.19  No reliable information.
Killer whale..............................              NA  ..............               3             552            0.54  Stable.
Harbor porpoise...........................              NA  ..............               3          48,215            0.01  No reliable information.
Bowhead whale.............................          0.0055  ..............              29          16,892            0.17  Increasing.
Gray whale................................              NA  ..............               3          19,126            0.02  Increasing.
Bearded seal..............................  ..............           0.107              87         155,000            0.06  No reliable information.
Ringed seal...............................  ..............           0.397             324         300,000            0.11  No reliable information.
Spotted seal..............................  ..............           0.126             103         141,479            0.07  No reliable information.
Ribbon seal...............................  ..............              NA               3          49,000            0.01  No reliable information.
--------------------------------------------------------------------------------------------------------------------------------------------------------


[[Page 21378]]

Analysis and Preliminary Determinations

Negligible Impact

    Negligible impact is ``an impact resulting from the specified 
activity that cannot be reasonably expected to, and is not reasonably 
likely to, adversely affect the species or stock through effects on 
annual rates of recruitment or survival'' (50 CFR 216.103). A 
negligible impact finding is based on the lack of likely adverse 
effects on annual rates of recruitment or survival (i.e., population-
level effects). An estimate of the number of Level B harassment takes, 
alone, is not enough information on which to base an impact 
determination. In addition to considering estimates of the number of 
marine mammals that might be ``taken'' through behavioral harassment, 
NMFS must consider other factors, such as the likely nature of any 
responses (their intensity, duration, etc.), the context of any 
responses (critical reproductive time or location, migration, etc.), as 
well as the number and nature of estimated Level A harassment takes, 
the number of estimated mortalities, effects on habitat, and the status 
of the species.
    No injuries or mortalities are anticipated to occur as a result of 
BP's proposed 3D OBS seismic survey, and none are proposed to be 
authorized. Additionally, animals in the area are not expected to incur 
hearing impairment (i.e., TTS or PTS) or non-auditory physiological 
effects. The number of takes that are anticipated and authorized are 
expected to be limited to short-term Level B behavioral harassment. 
While the airguns will be operated continuously for about 34 days, the 
project time frame will occur when cetacean species are typically not 
found in the project area or are found only in low numbers. While 
pinnipeds are likely to be found in the proposed project area more 
frequently, their distribution is dispersed enough that they likely 
will not be in the Level B harassment zone continuously. As mentioned 
previously in this document, pinnipeds appear to be more tolerant of 
anthropogenic sound than mystiectes.
    The Alaskan Beaufort Sea is part of the main migration route of the 
Western Arctic stock of bowhead whales. However, the seismic survey has 
been planned to occur when the majority of the population is found in 
the Canadian Beaufort Sea. Active airgun operations will cease by 
midnight on August 25 before the main fall migration begins and well 
before cow/calf pairs begin migrating through the area. Additionally, 
several locations within the Beaufort Sea serve as feeding grounds for 
bowhead whales. However, as mentioned earlier in this document, the 
primary feeding grounds are not found in Prudhoe Bay. The majority of 
bowhead whales feed in the Alaskan Beaufort Sea during the fall 
migration period, which will occur after the cessation of the airgun 
survey.
    Belugas that migrate through the U.S. Beaufort Sea typically do so 
farther offshore (more than 37 mi [60 km]) and in deeper waters (more 
than 656 ft [200 m]) than where the proposed 3D OBS seismic survey 
activities would occur. Gray whales are rarely sighted this far east in 
the U.S. Beaufort Sea. Additionally, there are no known feeding grounds 
for gray whales in the Prudhoe Bay area. The most northern feeding 
sites known for this species are located in the Chukchi Sea near Hanna 
Shoal and Point Barrow. The other cetacean species for which take is 
proposed are uncommon in Prudhoe Bay, and no known feeding or calving 
grounds occur in Prudhoe Bay for these species. Based on these factors, 
exposures of cetaceans to anthropogenic sounds are not expected to last 
for prolonged periods (i.e., several days or weeks) since they are not 
known to remain in the area for extended periods of time in July and 
August. Also, the shallow water location of the survey makes it 
unlikely that cetaceans would remain in the area for prolonged periods. 
Based on all of this information, the proposed project is not 
anticipated to affect annual rates of recruitment or survival for 
cetaceans in the area.
    Ringed seals breed and pup in the Alaskan Beaufort Sea; however, 
the proposed seismic survey will occur outside of the breeding and 
pupping seasons. The Beaufort Sea does not provide suitable habitat for 
the other three ice seal species for breeding and pupping. Based on 
this information, the proposed project is not anticipated to affect 
annual rates of recruitment or survival for pinnipeds in the area.
    Of the nine marine mammal species for which take is authorized, one 
is listed as endangered under the ESA--the bowhead whale--and two are 
listed as threatened--ringed and bearded seals. Schweder et al. (2009) 
estimated the yearly growth rate to be 3.2% (95% CI = 0.5-4.8%) between 
1984 and 2003 using a sight-resight analysis of aerial photographs. 
There are currently no reliable data on trends of the ringed and 
bearded seal stocks in Alaska. The ribbon seal is listed as a species 
of concern under the ESA. Certain stocks or populations of gray, 
killer, 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 activity area. There is currently no 
established critical habitat in the project area for any of these nine 
species.
    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 monitoring and 
mitigation measures, NMFS preliminarily finds that the total marine 
mammal take from BP's proposed 3D OBS seismic survey in Prudhoe Bay, 
Beaufort Sea, Alaska, will have a negligible impact on the affected 
marine mammal species or stocks.

Small Numbers

    The requested takes proposed to be authorized represent less than 
1% of all populations or stocks (see Table 9 in this document). These 
take estimates represent the percentage of each species or stock that 
could be taken by Level B behavioral harassment if each animal is taken 
only once. The numbers of marine mammals taken are small relative to 
the affected species or stock sizes. In addition, 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. NMFS preliminarily 
finds that small numbers of marine mammals will be taken relative to 
the populations of 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 the proposed seismic survey 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

[[Page 21379]]

these species varies among the communities and is largely based on 
availability.
    Residents of the village of Nuiqsut are the primary subsistence 
users in the project area. The communities of Barrow and Kaktovik also 
harvest resources that pass through the area of interest but do not 
hunt in or near the Prudhoe Bay area. Subsistence hunters from all 
three communities conduct an annual hunt for autumn-migrating bowhead 
whales. Barrow also conducts a bowhead hunt in spring. Residents of all 
three communities hunt seals. Other subsistence activities include 
fishing, waterfowl and seaduck harvests, and hunting for walrus, beluga 
whales, polar bears, caribou, and moose.
    Nuiqsut is the community closest to the seismic survey area 
(approximately 54 mi [87 km] southwest). Nuiqsut hunters harvest 
bowhead whales only during the fall whaling season (Long, 1996). In 
recent years, Nuiqsut whalers have typically landed three or four 
whales per year. Nuiqsut whalers concentrate their efforts on areas 
north and east of Cross Island, generally in water depths greater than 
66 ft (20 m; Galginaitis, 2009). Cross Island is the principal base for 
Nuiqsut whalers while they are hunting bowheads (Long, 1996). Cross 
Island is located approximately 35 mi (56.4 km) east of the seismic 
survey area.
    Kaktovik whalers search for whales east, north, and occasionally 
west of Kaktovik. Kaktovik is located approximately 120 mi (193 km) 
east of Prudhoe Bay. The western most reported harvest location was 
about 13 mi (21 km) west of Kaktovik, near 70[deg]10' N., 144[deg]11' 
W. (Kaleak, 1996). That site is about 112 mi (180 km) east of the 
proposed survey area.
    Barrow whalers search for whales much farther from the Prudhoe Bay 
area--about 155+ mi (250+ km) to the west. Barrow hunters have 
expressed concerns about ``downstream'' effects to bowhead whales 
during the westward fall migration; however, BP will cease airgun 
operations prior to the start of the fall migration.
    Beluga whales are not a prevailing subsistence resource in the 
communities of Kaktovik and Nuiqsut. Kaktovik hunters may harvest one 
beluga whale in conjunction with the bowhead hunt; however, it appears 
that most households obtain beluga through exchanges with other 
communities. Although Nuiqsut hunters have not hunted belugas for many 
years while on Cross Island for the fall hunt, this does not mean that 
they may not return to this practice in the future. Data presented by 
Braund and Kruse (2009) indicate that only 1% of Barrow's total harvest 
between 1962 and 1982 was of beluga whales and that it did not account 
for any of the harvested animals between 1987 and 1989.
    Ringed seals are available to subsistence users in the Beaufort Sea 
year-round, but they are primarily hunted in the winter or spring due 
to the rich availability of other mammals in the summer. Bearded seals 
are primarily hunted during July in the Beaufort Sea; however, in 2007, 
bearded seals were harvested in the months of August and September at 
the mouth of the Colville River Delta, which is approximately 50+ mi 
(80+ km) from the proposed seismic survey area. However, this sealing 
area can reach as far east as Pingok Island, which is approximately 20 
mi (32 km) west of the survey area. An annual bearded seal harvest 
occurs in the vicinity of Thetis Island (which is a considerable 
distance from Prudhoe Bay) in July through August. Approximately 20 
bearded seals are harvested annually through this hunt. Spotted seals 
are harvested by some of the villages in the summer months. Nuiqsut 
hunters typically hunt spotted seals in the nearshore waters off the 
Colville River Delta. The majority of the more established seal hunts 
that occur in the Beaufort Sea, such as the Colville delta area hunts, 
are located a significant distance (in some instances 50 mi [80 km] or 
more) from the project area.

Potential Impacts to Subsistence Uses

    NMFS has defined ``unmitigable adverse impact'' in 50 CFR 216.103 
as: ``. . . an impact resulting from the specified activity: (1) That 
is likely to reduce the availability of the species to a level 
insufficient for a harvest to meet subsistence needs by: (i) Causing 
the marine mammals to abandon or avoid hunting areas; (ii) Directly 
displacing subsistence users; or (iii) Placing physical barriers 
between the marine mammals and the subsistence hunters; and (2) 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 BP's proposed 3D OBS seismic 
survey have the potential to impact marine mammals hunted by Native 
Alaskan. In the case of cetaceans, the most common reaction to 
anthropogenic sounds (as noted previously) is avoidance of the 
ensonified area. In the case of bowhead whales, this often means that 
the animals divert from their normal migratory path by several 
kilometers. Helicopter activity also has the potential to disturb 
cetaceans and pinnipeds by causing them to vacate the area. 
Additionally, general vessel presence in the vicinity of traditional 
hunting areas could negatively impact a hunt. Native knowledge 
indicates that bowhead whales become increasingly ``skittish'' in the 
presence of seismic noise. Whales are more wary around the hunters and 
tend to expose a much smaller portion of their back when surfacing 
(which makes harvesting more difficult). Additionally, natives report 
that bowheads exhibit angry behaviors in the presence of seismic, such 
as tail-slapping, which translate to danger for nearby subsistence 
harvesters.

Plan of Cooperation or Measures To Minimize Impacts to Subsistence 
Hunts

    Regulations at 50 CFR 216.104(a)(12) require IHA applicants for 
activities that take place in Arctic waters to provide a Plan of 
Cooperation 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. BP has begun 
discussions with the Alaska Eskimo Whaling Commission (AEWC) to develop 
a Conflict Avoidance Agreement (CAA) intended to minimize potential 
interference with bowhead subsistence hunting. BP also attended and 
participated in meetings with the AEWC on December 13, 2013, and will 
attend future meetings to be scheduled in 2014. The CAA, when executed, 
will describe measures to minimize any adverse effects on the 
availability of bowhead whales for subsistence uses.
    The North Slope Borough Department of Wildlife Management (NSB-DWM) 
will be consulted, and BP plans to present the project to the NSB 
Planning Commission in 2014. BP will hold meetings in the community of 
Nuiqsut to present the proposed project, address questions and concerns 
from community members, and provide them with contact information of 
project management to which they can direct concerns during the survey. 
During the NMFS Open-Water Meeting in Anchorage in 2013, BP presented 
their proposed projects to various stakeholders that were present 
during this meeting.
    BP will continue to engage with the affected subsistence 
communities regarding its Beaufort Sea activities. As in previous 
years, BP will meet formally and/or informally with several stakeholder 
entities: the NSB Planning Department, NSB-DWM, NMFS, AEWC, Inupiat 
Community of the Arctic Slope, Inupiat History Language and Culture 
Center, USFWS, Nanuq and Walrus

[[Page 21380]]

Commissions, and Alaska Department of Fish & Game.
    Project information was provided to and input on subsistence 
obtained from the AEWC and Nanuq Commission at the following meetings:
     AEWC, October 17, 2013; and
     Nanuq Commission, October 17, 2013.
    Additional meetings with relevant stakeholders will be scheduled 
and a record of attendance and topics discussed will be maintained and 
submitted to NMFS.
    BP proposes to implement several mitigation measures to reduce 
impacts on the availability of marine mammals for subsistence hunts in 
the Beaufort Sea. Many of these measures were developed from the 2013 
CAA and previous NSB Development Permits. In addition to the measures 
listed next, BP will cease all airgun operations by midnight on August 
25 to allow time for the Beaufort Sea communities to prepare for their 
fall bowhead whale hunts prior to the beginning of the fall westward 
migration through the Beaufort Sea. Some of the measures mentioned next 
have been mentioned previously in this document:
     PSOs on board vessels are tasked with looking out for 
whales and other marine mammals in the vicinity of the vessel to assist 
the vessel captain in avoiding harm to whales and other marine mammals;
     Vessels and aircraft will avoid areas where species that 
are sensitive to noise or vessel movements are concentrated;
     Communications and conflict resolution are detailed in the 
CAA. BP will participate in the Communications Center that is operated 
annually during the bowhead subsistence hunt;
     Communications with the village of Nuiqsut to discuss 
community questions or concerns including all subsistence hunting 
activities. Pre-project meeting(s) with Nuiqsut representatives will be 
held at agreed times with groups in the community of Nuiqsut. If 
additional meetings are requested, they will be set up in a similar 
manner;
     Contact information for BP will be provided to community 
members and distributed in a manner agreed at the community meeting;
     BP has contracted with a liaison from Nuiqsut who will 
help coordinate meetings and serve as an additional contact for local 
residents during planning and operations; and
     Inupiat Communicators will be employed and work on seismic 
source vessels. They will also serve as PSOs.

Unmitigable Adverse Impact Analysis and Preliminary Determination

    BP has adopted a spatial and temporal strategy for its Prudhoe Bay 
survey that should minimize impacts to subsistence hunters. First, BP's 
activities will not commence until after the spring hunts have 
occurred. Second, BP will cease all airgun operations by midnight on 
August 25 prior to the start of the bowhead whale fall westward 
migration and any fall subsistence hunts by Beaufort Sea communities. 
Prudhoe Bay is not commonly used for subsistence hunts. Although some 
seal hunting co-occurs temporally with BP's proposed seismic survey, 
the locations do not overlap. BP's presence will not place physical 
barriers between the sealers and the seals. Additionally, BP will work 
closely with the closest affected communities and support 
Communications Centers and employ local Inupiat Communicators. Based on 
the description of the specified activity, the measures described to 
minimize adverse effects on the availability of marine mammals for 
subsistence purposes, and the proposed mitigation and monitoring 
measures, NMFS has preliminarily determined that there will not be an 
unmitigable adverse impact on subsistence uses from BP's proposed 
activities.

Endangered Species Act (ESA)

    Within the project area, the bowhead whale is listed as endangered 
and the ringed and bearded seals are listed as threatened under the 
ESA. NMFS' Permits and Conservation Division has initiated consultation 
with staff in NMFS' Alaska Region Protected Resources Division under 
section 7 of the ESA on the issuance of an IHA to BP 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 conducting an analysis, pursuant to NEPA, to 
determine whether this proposed IHA may have a significant effect on 
the human environment. This analysis will be completed prior to the 
issuance or denial of this proposed IHA.

Proposed Authorization

    As a result of these preliminary determinations, NMFS proposes to 
issue an IHA to BP for conducting a 3D OBS seismic survey in the 
Prudhoe Bay area of the Beaufort Sea, Alaska, during the 2014 open-
water season, provided the previously mentioned mitigation, monitoring, 
and reporting requirements are incorporated. The proposed IHA language 
is provided next.
    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 IHA is valid from July 1, 2014, through September 30, 2014.
    2. This IHA is valid only for activities associated with open-water 
OBS seismic surveys and related activities in the Beaufort Sea. The 
specific areas where BP's surveys will be conducted are within the 
Prudhoe Bay Area, Beaufort Sea, Alaska, as shown in Figures 1 and 2 of 
BP's IHA application.
    3. Species Authorized and Level of Take
    a. The incidental taking of marine mammals, by Level B harassment 
only, is limited to the following species in the waters of the Beaufort 
Sea:
    i. Odontocetes: 75 beluga whales; 3 killer whales; and 3 harbor 
porpoises.
    ii. Mysticetes: 29 bowhead whales and 3 gray whales.
    iii. Pinnipeds: 324 ringed seals; 87 bearded seals; 103 spotted 
seals; and 3 ribbon seals.
    iv. If any marine mammal species not listed in conditions 3(a)(i) 
through (iii) are encountered during seismic survey operations and are 
likely to be exposed to sound pressure levels (SPLs) greater than or 
equal to 160 dB re 1 [mu]Pa (rms) for impulse sources, then the Holder 
of this IHA must shut-down the sound source to avoid take.
    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 IHA.
    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. 620 in\3\ airgun arrays;
    b. 1,240 in\3\ airgun arrays;
    c. 40 in\3\ and/or 10 in\3\ mitigation airguns; and
    d. Vessel activities related to the OBS seismic survey.
    5. The taking of any marine mammal in a manner prohibited under 
this Authorization must be reported within 24 hours of the taking to 
the Alaska Regional Administrator or his designee and the Chief of the 
Permits and Conservation Division, Office of Protected Resources, NMFS, 
or her designee.
    6. The holder of this Authorization must notify the Chief of the 
Permits and

[[Page 21381]]

Conservation Division, Office of Protected Resources, at least 48 hours 
prior to the start of collecting seismic data (unless constrained by 
the date of issuance of this IHA in which case notification shall be 
made as soon as possible).
    7. Mitigation Requirements: The Holder of this Authorization is 
required to implement the following mitigation requirements when 
conducting the specified activities to achieve the least practicable 
impact on affected marine mammal species or stocks:
a. General Vessel and Aircraft Mitigation
    i. Avoid concentrations or groups of whales by all vessels under 
the direction of BP. Operators of support vessels should, at all times, 
conduct their activities at the maximum distance possible from such 
concentrations of whales.
    ii. Transit and node laying vessels shall be operated at speeds 
necessary to ensure no physical contact with whales occurs. If any 
barge or transit vessel approaches within 1.6 km (1 mi) of observed 
whales, except when providing emergency assistance to whalers or in 
other emergency situations, the vessel operator will take reasonable 
precautions to avoid potential interaction with the whales by taking 
one or more of the following actions, as appropriate:
    A. Reducing vessel speed to less than 5 knots within 300 yards (900 
feet or 274 m) of the whale(s);
    B. Steering around the whale(s) if possible;
    C. Operating the vessel(s) in such a way as to avoid separating 
members of a group of whales from other members of the group;
    D. Operating the vessel(s) to avoid causing a whale to make 
multiple changes in direction;
    E. Checking the waters immediately adjacent to the vessel(s) to 
ensure that no whales will be injured when the propellers are engaged; 
and
    F. Reducing vessel speed to less than 9 knots when weather 
conditions reduce visibility.
    iii. When weather conditions require, such as when visibility 
drops, adjust vessel speed accordingly to avoid the likelihood of 
injury to whales.
    iv. In the event that any aircraft (such as helicopters) are used 
to support the planned survey, the mitigation measures below would 
apply:
    A. Under no circumstances, other than an emergency, shall aircraft 
be operated at an altitude lower than 1,000 feet above sea level when 
within 0.3 mile (0.5 km) of groups of whales.
    B. Helicopters shall not hover or circle above or within 0.3 mile 
(0.5 km) of groups of whales.
    C. At all other times, aircraft should attempt not to fly below 
1,000 ft except during emergencies and take-offs and landings.
    b. Seismic Airgun Mitigation
    i. Whenever a marine mammal is detected outside the exclusion zone 
radius and based on its position and motion relative to the ship track 
is likely to enter the exclusion radius, calculate and implement an 
alternative ship speed or track or de-energize the airgun array, as 
described in condition 7(b)(iv) below.
    ii. Exclusion Zones:
    A. Establish and monitor with trained PSOs an exclusion zone for 
cetaceans surrounding the airgun array on the source vessel where the 
received level would be 180 dB re 1 [mu]Pa rms. This radius is 
estimated to be 600 m from the seismic source for the 620 in\3\ airgun 
arrays, 200 m for a single 40 in\3\ airgun, and 50 m for a single 10 
in\3\ airgun.
    B. Establish and monitor with trained PSOs an exclusion zone for 
pinnipeds surrounding the airgun array on the source vessel where the 
received level would be 190 dB re 1 [mu]Pa rms. This radius is 
estimated to be 300 m from the seismic source for the 620 in\3\ airgun 
arrays, 70 m for the single 40 in\3\ airgun, and 20 m for a single 10 
in\3\ airgun.
    iii. Ramp-up
    A. A ramp-up, following a cold start, can be applied if the 
exclusion zone has been free of marine mammals for a consecutive 30-
minute period. The entire exclusion zone must have been visible during 
these 30 minutes. If the entire exclusion zone is not visible, then 
ramp-up from a cold start cannot begin.
    B. Ramp-up procedures from a cold start shall be delayed if a 
marine mammal is sighted within the exclusion zone during the 30-minute 
period prior to the ramp up. The delay shall last until the marine 
mammal(s) has been observed to leave the exclusion zone or until the 
animal(s) is not sighted for at least 15 or 30 minutes. The 15 minutes 
applies to pinnipeds, while a 30 minute observation period applies to 
cetaceans.
    C. A ramp-up, following a shutdown, can be applied if the marine 
mammal(s) for which the shutdown occurred has been observed to leave 
the exclusion zone or until the animal(s) is not sighted for at least 
15 minutes (pinnipeds) or 30 minutes (cetaceans).
    D. If, for any reason, electrical power to the airgun array has 
been discontinued for a period of 10 minutes or more, ramp-up 
procedures shall be implemented. Only if the PSO watch has been 
suspended, a 30-minute clearance of the exclusion zone is required 
prior to commencing ramp-up. Discontinuation of airgun activity for 
less than 10 minutes does not require a ramp-up.
    E. The seismic operator and PSOs shall maintain records of the 
times when ramp-ups start and when the airgun arrays reach full power.
    F. The ramp-up will be conducted by doubling the number of 
operating airguns at 5-minute intervals, starting with the smallest gun 
in the array.
    iv. Power-down/Shutdown
    A. The airgun array shall be immediately powered down (reduction in 
the number of operating airguns such that the radii of exclusion zones 
are decreased) whenever a marine mammal is sighted approaching close to 
or within the applicable exclusion zone of the full array, but is 
outside the applicable exclusion zone of the single mitigation airgun.
    B. If a marine mammal is already within the exclusion zone when 
first detected, the airguns shall be powered down immediately.
    C. Following a power-down, ramp-up to the full airgun array shall 
not resume until the marine mammal has cleared the exclusion zone. The 
animal will be considered to have cleared the exclusion zone if it is 
visually observed to have left the exclusion zone of the full array, or 
has not been seen within the zone for 15 minutes (pinnipeds) or 30 
minutes (cetaceans).
    D. If a marine mammal is sighted within or about to enter the 190 
or 180 dB (rms) applicable exclusion zone of the single mitigation 
airgun, the airgun array shall be shutdown immediately.
    E. Airgun activity after a complete shutdown shall not resume until 
the marine mammal has cleared the exclusion zone of the full array. The 
animal will be considered to have cleared the exclusion zone as 
described above under ramp-up procedures.
    v. Poor Visibility Conditions
    A. If during foggy conditions, heavy snow or rain, or darkness, the 
full 180 dB exclusion zone is not visible, the airguns cannot commence 
a ramp-up procedure from a full shut-down.
    B. If one or more airguns have been operational before nightfall or 
before the onset of poor visibility conditions, they can remain 
operational throughout the night or poor visibility conditions. In this 
case ramp-up procedures can be initiated, even though the exclusion 
zone may not be visible, on the assumption that marine mammals will be 
alerted by the sounds from the single airgun and have moved away.
    C. The mitigation airgun will be operated at approximately one shot 
per

[[Page 21382]]

minute and will not be operated for longer than three hours in duration 
during daylight hours and good visibility. In cases when the next 
start-up after the turn is expected to be during lowlight or low 
visibility, use of the mitigation airgun may be initiated 30 minutes 
before darkness or low visibility conditions occur and may be operated 
until the start of the next seismic acquisition line. The mitigation 
gun must still be operated at approximately one shot per minute.
c. Subsistence Mitigation
    i. Airgun operations must cease no later than midnight on August 
25, 2014;
    ii. BP will participate in the Communications Center that is 
operated annually during the bowhead subsistence hunt; and
    iii. Inupiat communicators will work on the seismic vessels.
    8. Monitoring
    a. The holder of this Authorization must designate biologically-
trained, on-site individuals (PSOs) to be onboard the source vessels, 
who are approved in advance by NMFS, to conduct the visual monitoring 
programs required under this Authorization and to record the effects of 
seismic surveys and the resulting sound on marine mammals.
    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.
    ii. Crew leaders and most other biologists serving as observers 
will be individuals with experience as observers during recent seismic 
or shallow hazards monitoring projects in Alaska, the Canadian 
Beaufort, or other offshore areas in recent years.
    iii. PSOs shall complete a training session on marine mammal 
monitoring, to be conducted shortly before the anticipated start of the 
2014 open-water season. The training session(s) will be conducted by 
qualified marine mammalogists with extensive crew-leader experience 
during previous vessel-based monitoring programs. An observers' 
handbook, adapted for the specifics of the planned survey program will 
be reviewed as part of the training.
    iv. 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.
    v. Crew members should not be used as primary PSOs because they 
have other duties and generally do not have the same level of 
expertise, experience, or training as PSOs, but they could be stationed 
on the fantail of the vessel to observe the near field, especially the 
area around the airgun array and implement a power-down or shutdown if 
a marine mammal enters the exclusion zone).
    vi. If crew members are to be used as PSOs, they shall go through 
some basic training consistent with the functions they will be asked to 
perform. The best approach would be for crew members and PSOs to go 
through the same training together.
    vii. 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.
    viii. BP shall train its PSOs to follow a scanning schedule that 
consistently distributes scanning effort according to the purpose and 
need for observations. For example, the schedule might call for 60% of 
scanning effort to be directed toward the near field and 40% at the far 
field. All PSOs should follow the same schedule to ensure consistency 
in their scanning efforts.
    ix. PSOs shall be trained in documenting the behaviors of marine 
mammals. PSOs should simply record the primary behavioral state (i.e., 
traveling, socializing, feeding, resting, approaching or moving away 
from vessels) and relative location of the observed marine mammals.
    b. To the extent possible, PSOs should be on duty for four (4) 
consecutive hours or less, although more than one four-hour shift per 
day is acceptable; however, an observer shall not be on duty for more 
than 12 hours in a 24-hour period.
    c. Monitoring is to be conducted by the PSOs onboard the active 
seismic vessels to ensure that no marine mammals enter the appropriate 
exclusion zone whenever the seismic acoustic sources are on and to 
record marine mammal activity as described in condition 8(f). Two PSOs 
will be present on each seismic source vessel. At least one PSO shall 
monitor for marine mammals at any time during daylight hours.
    d. At all times, the crew must be instructed to keep watch for 
marine mammals. If any are sighted, the bridge watch-stander must 
immediately notify the PSO(s) on-watch. If a marine mammal is within or 
closely approaching its designated exclusion zone, the seismic acoustic 
sources must be immediately powered down or shutdown (in accordance 
with condition 7(b)(iv)).
    e. Observations by the PSOs on marine mammal presence and activity 
will begin a minimum of 30 minutes prior to the estimated time that the 
seismic source is to be turned on and/or ramped-up.
    f. All marine mammal observations and any airgun power-down, shut-
down and ramp-up will be recorded in a standardized format. Data will 
be entered into a custom database. The accuracy of the data entry will 
be verified daily through QA/QC procedures. These procedures will allow 
initial summaries of data to be prepared during and shortly after the 
field program, and will facilitate transfer of the data to other 
programs for further processing and archiving.
    g. Monitoring shall consist of recording:
    i. The species, group size, age/size/sex categories (if 
determinable), the general behavioral activity, heading (if 
consistent), bearing and distance from seismic vessel, sighting cue, 
behavioral pace, and apparent reaction of all marine mammals seen near 
the seismic vessel and/or its airgun array (e.g., none, avoidance, 
approach, paralleling, etc);
    ii. The time, location, heading, speed, and activity of the vessel 
(shooting or not), along with sea state, visibility, cloud cover and 
sun glare at:
    A. Any time a marine mammal is sighted (including pinnipeds hauled 
out on barrier islands),
    B. At the start and end of each watch, and
    C. During a watch (whenever there is a change in one or more 
variable);
    iii. The identification of all vessels that are visible within 5 km 
of the seismic vessel whenever a marine mammal is sighted, and the time 
observed, bearing, distance, heading, speed and activity of the other 
vessel(s);
    iv. Any identifiable marine mammal behavioral response (sighting 
data should be collected in a manner that will not detract from the 
PSO's ability to detect marine mammals);
    v. Any adjustments made to operating procedures; and
    iv. Visibility during observation periods so that total estimates 
of take can be corrected accordingly.
    h. BP shall work with its observers to develop a means for 
recording data that does not reduce observation time significantly.
    i. PSOs shall use the best possible positions for observing (e.g., 
outside and as high on the vessel as possible), taking into account 
weather and other working conditions. PSOs shall carefully document 
visibility during observation

[[Page 21383]]

periods so that total estimates of take can be corrected accordingly.
    j. PSOs shall scan systematically with the unaided eye and reticle 
binoculars, and other devices.
    k. PSOs shall attempt to maximize the time spent looking at the 
water and guarding the exclusion radii. They shall avoid the tendency 
to spend too much time evaluating animal behavior or entering data on 
forms, both of which detract from their primary purpose of monitoring 
the exclusion zone.
    l. Night-vision equipment (Generation 3 binocular image 
intensifiers, or equivalent units) shall be available for use during 
low light hours, and BP shall continue to research methods of detecting 
marine mammals during periods of low visibility.
    m. PSOs shall understand the importance of classifying marine 
mammals as ``unknown'' or ``unidentified'' if they cannot identify the 
animals to species with confidence. In those cases, they shall note any 
information that might aid in the identification of the marine mammal 
sighted. For example, for an unidentified mysticete whale, the 
observers should record whether the animal had a dorsal fin.
    n. Additional details about unidentified marine mammal sightings, 
such as ``blow only'', mysticete with (or without) a dorsal fin, ``seal 
splash'', etc., shall be recorded.
    o. BP shall conduct a fish and airgun sound monitoring program as 
described in the IHA application and further refined in consultation 
with an expert panel.
    9. Data Analysis and Presentation in Reports:
    a. Estimation of potential takes or exposures shall be improved for 
times with low visibility (such as during fog or darkness) through 
interpolation or possibly using a probability approach. Those data 
could be used to interpolate possible takes during periods of 
restricted visibility.
    b. Water depth should be continuously recorded by the vessel and 
for each marine mammal sighting. Water depth should be accounted for in 
the analysis of take estimates.
    c. BP shall be very clear in their report about what periods are 
considered ``non-seismic'' for analyses.
    d. BP shall examine data from ASAMM and other such programs to 
assess possible impacts from their seismic survey.
    e. To better assess impacts to marine mammals, data analysis shall 
be separated into periods when a seismic airgun array (or a single 
mitigation airgun) is operating and when it is not. Final and 
comprehensive reports to NMFS should summarize and plot:
    i. Data for periods when a seismic array is active and when it is 
not; and
    ii. The respective predicted received sound conditions over fairly 
large areas (tens of km) around operations.
    f. To help evaluate the effectiveness of PSOs and more effectively 
estimate take, if appropriate data are available, BP shall perform 
analysis of sightability curves (detection functions) for distance-
based analyses.
    g. BP should improve take estimates and statistical inference into 
effects of the activities by incorporating the following measures:
    i. Reported results from all hypothesis tests should include 
estimates of the associated statistical power when practicable.
    ii. 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.
    10. Reporting Requirements
    The Holder of this Authorization is required to:
    a. A report will be submitted to NMFS within 90 days after the end 
of the proposed seismic survey. The report will summarize all 
activities and monitoring results conducted during in-water seismic 
surveys. The Technical Report will include the following:
    i. Summary of project start and end dates, airgun activity, number 
of guns, and the number and circumstances of implementing ramp-up, 
power down, shutdown, and other mitigation actions;
    ii. 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);
    iii. Analyses of the effects of various factors influencing 
detectability of marine mammals (e.g., sea state, number of observers, 
and fog/glare);
    iv. Species composition, occurrence, and distribution of marine 
mammal sightings, including date, water depth, numbers, age/size/gender 
categories (if determinable), and group sizes;
    v. Analyses of the effects of survey operations;
    vi. Sighting rates of marine mammals during periods with and 
without seismic survey activities (and other variables that could 
affect detectability), such as:
    A. Initial sighting distances versus survey activity state;
    B. Closest point of approach versus survey activity state;
    C. Observed behaviors and types of movements versus survey activity 
state;
    D. Numbers of sightings/individuals seen versus survey activity 
state;
    E. Distribution around the source vessels versus survey activity 
state; and
    F. Estimates of exposures of marine mammals to Level B harassment 
thresholds based on presence in the 160 dB harassment zone.
    b. 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.
    c. BP will present the results of the fish and airgun sound study 
to NMFS in a detailed report.
    11. Notification of Dead or Injured Marine Mammals
    a. In the unanticipated event that the specified activity clearly 
causes the take of a marine mammal in a manner prohibited by the IHA, 
such as an injury (Level A harassment), serious injury or mortality 
(e.g., ship-strike, gear interaction, and/or entanglement), BP would 
immediately cease the specified activities and immediately report the 
incident to the Chief of the Permits and Conservation Division, Office 
of Protected Resources, NMFS, and the Alaska Regional Stranding 
Coordinators. The report would include the following information:
     Time, date, and location (latitude/longitude) of the 
incident;
     Name and type of vessel involved;
     Vessel's speed during and leading up to the incident;
     Description of the incident;
     Status of all sound source use in the 24 hours preceding 
the incident;
     Water depth;
     Environmental conditions (e.g., wind speed and direction, 
Beaufort sea state, cloud cover, and visibility);
     Description of all marine mammal observations in the 24 
hours preceding the incident;
     Species identification or description of the animal(s) 
involved;
     Fate of the animal(s); and
     Photographs or video footage of the animal(s) (if 
equipment is available).
    Activities would not resume until NMFS is able to review the 
circumstances of the prohibited take. NMFS would work with BP to 
determine what is necessary to minimize the likelihood of further 
prohibited take and ensure MMPA

[[Page 21384]]

compliance. BP would not be able to resume their activities until 
notified by NMFS via letter, email, or telephone.
    b. In the event that BP 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), BP 
would immediately report the incident to the Chief of the Permits and 
Conservation Division, Office of Protected Resources, NMFS, and the 
NMFS Alaska Stranding Hotline and/or by email to the Alaska Regional 
Stranding Coordinators. The report would include the same information 
identified in the paragraph above. Activities would be able to continue 
while NMFS reviews the circumstances of the incident. NMFS would work 
with BP to determine whether modifications in the activities are 
appropriate.
    c. In the event that BP 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 the IHA (e.g., 
previously wounded animal, carcass with moderate to advanced 
decomposition, or scavenger damage), BP would report the incident to 
the Chief of the Permits and Conservation Division, Office of Protected 
Resources, NMFS, and the NMFS Alaska Stranding Hotline and/or by email 
to the Alaska Regional Stranding Coordinators, within 24 hours of the 
discovery. BP would provide photographs or video footage (if available) 
or other documentation of the stranded animal sighting to NMFS and the 
Marine Mammal Stranding Network.
    12. Activities related to the monitoring described in this IHA do 
not require a separate scientific research permit issued under section 
104 of the MMPA.
    13. BP is required to comply with the Reasonable and Prudent 
Measures and Terms and Conditions of the Incidental Take Statement 
(ITS) corresponding to NMFS' Biological Opinion.
    14. A copy of this IHA and the ITS must be in the possession of all 
contractors and PSOs operating under the authority of this IHA.
    15. 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.
    16. 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.

Request for Public Comments

    NMFS requests comment on our analysis, the draft authorization, and 
any other aspect of the Notice of Proposed IHA for BP's proposed 3D OBS 
seismic survey in the Prudhoe Bay area of the Beaufort Sea, Alaska, 
during the 2014 open-water season. Please include with your comments 
any supporting data or literature citations to help inform our final 
decision on BP's request for an MMPA authorization.

    Dated: April 8, 2014.
Donna S. Wieting,
Director, Office of Protected Resources, National Marine Fisheries 
Service.
[FR Doc. 2014-08352 Filed 4-14-14; 8:45 am]
BILLING CODE 3510-22-P