Taking and Importing Marine Mammals:

Federal Register Volume 76, Number 129 (Wednesday, July 6, 2011)

Proposed Rules

Pages 39706-39747

From the Federal Register Online via the Government Printing Office [www.gpo.gov]

FR Doc No: 2011-16327

Page 39705

Vol. 76

Wednesday,

No. 129

July 6, 2011

Part V

Department of Commerce

National Oceanic and Atmospheric Administration

50 CFR Part 217

Taking and Importing Marine Mammals; Taking Marine Mammals Incidental to Operation of Offshore Oil and Gas Facilities in the U.S. Beaufort

Sea; Proposed Rule

Proposed Rules

Page 39706

DEPARTMENT OF COMMERCE

National Oceanic and Atmospheric Administration 50 CFR Part 217

Docket No. 100217096-1312-01

RIN 0648-AY63

Taking and Importing Marine Mammals; Taking Marine Mammals

Incidental to Operation of Offshore Oil and Gas Facilities in the U.S.

Beaufort Sea

AGENCY: National Marine Fisheries Service (NMFS), National Oceanic and

Atmospheric Administration (NOAA), Commerce.

ACTION: Proposed rule; request for comments.

SUMMARY: NMFS has received a request from BP Exploration (Alaska) Inc.

(BP) for authorization for the take of marine mammals incidental to operation of offshore oil and gas facilities in the U.S. Beaufort Sea,

Alaska, for the period 2011-2016. Pursuant to the Marine Mammal

Protection Act (MMPA), NMFS is proposing to issue regulations to govern that take and requesting information, suggestions, and comments on these proposed regulations. These regulations, if issued, would include required mitigation measures to ensure the least practicable adverse impact on the affected marine mammal species and stocks.

DATES: Comments and information must be received no later than August 5, 2011.

ADDRESSES: You may submit comments, identified by 0648-AY63, by any one of the following methods:

Electronic Submissions: Submit all electronic public comments via the Federal eRulemaking Portal http://www.regulations.gov.

Hand delivery or mailing of paper, disk, or CD-ROM comments should be addressed to Michael Payne, Chief, Permits,

Conservation and Education Division, Office of Protected Resources,

National Marine Fisheries Service, 1315 East-West Highway, Silver

Spring, MD 20910.

Comments regarding any aspect of the collection of information requirement contained in this proposed rule should be sent to NMFS via one of the means stated here and to the Office of Information and

Regulatory Affairs, NEOB-10202, Office of Management and Budget (OMB),

Attn: Desk Office, Washington, DC 20503, OIRA@omb.eop.gov.

Instructions: All comments received are a part of the public record and will generally be posted to http://www.regulations.gov without change. All Personal Identifying Information (for example, name, address, etc.) voluntarily submitted by the commenter may be publicly accessible. Do not submit Confidential Business Information or otherwise sensitive or protected information.

NMFS will accept anonymous comments (enter N/A in the required fields if you wish to remain anonymous). Attachments to electronic comments will be accepted in Microsoft Word, Excel, WordPerfect, or

Adobe PDF file formats only.

FOR FURTHER INFORMATION CONTACT: Candace Nachman, Office of Protected

Resources, NMFS, (301) 713-2289, ext. 156, or Brad Smith, Alaska

Region, NMFS, (907) 271-3023.

SUPPLEMENTARY INFORMATION:

Availability

A copy of BP's application may be obtained by writing to the address specified above (see ADDRESSES), calling the contact listed above (see FOR FURTHER INFORMATION CONTACT), or visiting the Internet at: http://www.nmfs.noaa.gov/pr/permits/incidental.htm. To help NMFS process and review comments more efficiently, please use only one method to submit comments.

Background

Sections 101(a)(5)(A) and (D) of the MMPA (16 U.S.C. 1361 et seq.) direct the Secretary of Commerce (Secretary) to allow, upon request, the incidental, but not intentional taking of marine mammals by U.S. citizens who engage in a specified activity (other than commercial fishing) during periods of not more than five consecutive years each if certain findings are made and regulations are issued or, if the taking is limited to harassment, notice of a proposed authorization is provided to the public for review.

Authorization 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, and if the permissible methods of taking and requirements pertaining to the mitigation, monitoring and reporting of such taking 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 November 6, 2009, NMFS received an application from BP requesting authorization for the take of six marine mammal species incidental to operation of the Northstar development in the Beaufort

Sea, Alaska, over the course of 5 years, which would necessitate the promulgation of new five-year regulations. Construction of Northstar was completed in 2001. The proposed activities for 2011-2016 include a continuation of drilling, production, and emergency training operations but no construction or activities of similar intensity to those conducted between 1999 and 2001. The likely or possible impacts of the planned continuing operations at Northstar on marine mammals involve both non-acoustic and acoustic effects. Potential non-acoustic effects could result from the physical presence of personnel, structures and equipment, construction or maintenance activities, and the occurrence of oil spills. Petroleum development and associated activities in marine waters introduce sound into the environment, produced by island construction, maintenance, and drilling, as well as vehicles operating on the ice, vessels, aircraft, generators, production machinery, gas flaring, and camp operations. BP requests authorization to take individuals of three cetacean and three pinniped species by Level B

Harassment. They are: Bowhead, gray, and beluga whales and ringed, bearded, and spotted seals. Further, BP requests authorization to take five individual ringed seals by injury or mortality annually over the course of the 5-year rule.

Description of the Specified Activity

Background on the Northstar Development Facility

BP is currently producing oil from an offshore development in the

Northstar Unit (see Figure 1 in BP's application). This development is the first in the Beaufort Sea that makes use of a subsea pipeline to transport oil to shore and

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then into the Trans-Alaska Pipeline System. The Northstar facility was built in State of Alaska waters on the remnants of Seal Island approximately 6 mi (9.5 km) offshore from Point Storkersen, northwest of the Prudhoe Bay industrial complex, and 3 mi (5 km) seaward of the closest barrier island. It is located approximately 54 mi (87 km) northeast of Nuiqsut, an Inupiat community.

The main facilities associated with Northstar include a gravel island work surface for drilling and oil production facilities and two pipelines connecting the island to the existing infrastructure at

Prudhoe Bay. One pipeline transports crude oil to shore, and the second imports gas from Prudhoe Bay for gas injection at Northstar. Permanent living quarters and supporting oil production facilities are also located on the island.

The construction of Northstar began in early 2000 and continued through 2001. BP states that activities with similar intensity to those that occurred during the construction phase between 2000 and 2001 are not planned or expected for any date within the 5-year period that would be governed by the proposed regulations (i.e., 2011-2016). Well drilling began on December 14, 2000, and oil production commenced on

October 31, 2001. Construction and maintenance activities occurred annually on the protection barrier around Northstar due to ice and storm impacts. In August 2003, two barges made a total of 52 round- trips to haul 30,000 cubic yards of gravel from West Dock for berm construction. Depending on the actual damage, repair and maintenance in the following years consisted of activities such as creating a moat for diver access, removing concrete blocks in areas that had sustained erosion and/or block damage, and installing a new layer of filter fabric. In 2008, BP installed large boulders at the NE corner of the barrier instead of replacing the lower concrete blocks that were removed during a storm.

The planned well-drilling program for Northstar was completed in

May 2004. Drilling activities to drill new wells, conduct well maintenance, and drill well side-tracks continued in 2006 (six wells), 2007 (two wells), and 2008 (two wells). The drill rig was demobilized and removed from the island by barge during the 2010 open water period.

Although future drilling is not specifically planned, drilling of additional wells or well work-over may be required at some time in the future. A more detailed description of past construction, drilling, and production activities at Northstar can be found in BP's application

(see ADDRESSES).

Expected Activities in 2011-2016

During the 5-year period from 2011-2016, BP intends to continue production and emergency training operations. As mentioned previously, drilling is not specifically planned for the 2011-2016 time period but may be required at some point in the future. The activities described next could occur at any time during the 5-year period. Table 2 in BP's application (see ADDRESSES) summarizes the vehicles and machinery used during BP's Northstar activities since the development of Northstar

Island. Although all these activities are not planned to take place during the 2011-2016 operational phase, some of the equipment may be required to repair or replace existing structures or infrastructure on

Northstar in the future.

(1) Transportation of Personnel, Equipment, and Supplies

Transportation needs for the Northstar project include the ability to safely transport personnel, supplies, and equipment to and from the site during repairs or maintenance, drilling, and operations in an offshore environment. During proposed island renewal construction that may take place during the requested time period, quantities of pipes, vertical support members (i.e., posts that hold up terrestrial pipelines), gravel, and a heavy module will be transported to the site.

Drilling operations require movement of pipe materials, chemicals, and other supplies to the island. During ongoing field operations, equipment and supplies will need to be transported to the site. All phases of construction, drilling, and operation require movement of personnel to and from the Northstar area.

During the operations phase from 2002-2009, fewer ice roads were required compared to the construction phase (2000-2001). The future scope of ice road construction activities during ongoing production is expected to be similar to the post-construction period of 2002-2009.

The locations, dimensions, and construction techniques of these ice roads are described in the multi-year final comprehensive report

(Richardson [ed.], 2008). The presence of ice roads allows the use of standard vehicles such as pick-ups, SUVs, buses and trucks for transport of personnel and equipment to and from Northstar during the ice-covered period. Ice roads are planned to be constructed and used as a means of winter transportation for the duration of Northstar operations. The orientation of future ice roads is undetermined, but will not exceed the number of ice roads created during the winter of 2000/2001.

Barges and Alaska Clean Seas (ACS) vessels are used to transport personnel and equipment from the Prudhoe Bay area to Northstar during the open-water season, which extends from approximately mid- to late-

July through early to mid-October. Seagoing barges are used to transport large modules and other supplies and equipment during the construction period.

Helicopter access to Northstar Island continues to be an important transportation option during break-up and freeze-up of the sea ice when wind, ice conditions, or other operational considerations prevent or limit hovercraft travel. Helicopters will be used for movement of personnel and supplies in the fall after freeze-up begins and vessel traffic is not possible but before ice roads have been constructed.

Helicopters will also be used in the spring after ice roads are no longer safe for all-terrain vehicles (ATVs) but before enough open water is available for vessel traffic. Helicopters are also available for use at other times of year in emergency situations. Helicopters fly at an altitude of at least 1,000 ft (305 m), except for take-off, landing, and as dictated for safe aircraft operations. Designated flight paths are assigned to minimize potential disturbance to wildlife and subsistence users.

The hovercraft is used to transport personnel and supplies during break-up and freeze-up periods to reduce helicopter use. BP intends to continue the use of the hovercraft in future years. Specifications of the hovercraft and sound characteristics are described in Richardson

([ed.] 2008) and Blackwell and Greene (2005).

(2) Production Operations

The process facilities for the Northstar project are primarily prefabricated sealift modules that were shipped to the island and installed in 2001. The operational aspects of the Northstar production facility include the following: Two diesel generators (designated emergency generators); three turbine generators for the power plant, operating at 50 percent duty cycle (i.e., only two will be operating at any one time); two high pressure turbine compressors; one low pressure flare; and one high pressure flare. Both flares are located on the 215 ft (66 m) flare tower. Modules for the facility include permanent living quarters (i.e., housing, kitchen/dining, lavatories, medical, recreation, office, and laundry space), utility module (i.e., desalinization plant,

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emergency power, and wastewater treatment plant), warehouse/shop module, communications module, diesel and potable water storage, and chemical storage. Operations have been continuing since oil production began on October 31, 2001 and are expected to continue beyond 2016.

(3) Drilling Operations

The drilling rig and associated equipment was moved by barge to

Northstar Island from Prudhoe Bay during the open-water season in 2000.

Drilling began in December 2000 using power supplied by the installed gas line. The first well drilled was the Underground Injection Control well, which was commissioned for disposal of permitted muds and cuttings on January 26, 2001. After Northstar facilities were commissioned, drilling above reservoir depth resumed, while drilling below that depth is allowed only during the ice covered period.

Although future drilling is not specifically planned during the requested time period for this proposed rule, drilling of additional wells or well work-over may be required at some time during 2011-2016.

(4) Pipeline Design, Inspection, and Maintenance

The Northstar pipelines have been designed, installed, and monitored to assure safety and leak prevention. Pipeline monitoring and surveillance activities have been conducted since oil production began, and BP will conduct long-term monitoring of the pipeline system to assure design integrity and to detect any potential problems through the life of the Northstar development. The program will include visual inspections/aerial surveillance and pig (a gauging/cleaning device) inspections.

The Northstar pipelines include the following measures to assure safety and leak prevention:

Under the pipeline design specifications, the tops of the pipes are 6-8 ft (1.8-2.4 m) below the original seabed (this is 2 times the deepest measured ice gouge);

The oil pipeline uses higher yield steel than required by design codes as applied to internal pressure (by a factor of over 2.5 times). This adds weight and makes the pipe stronger. The 10-in (25.4- cm) diameter Northstar oil pipeline has thicker walls than the 48-in

(122-cm) diameter Trans-Alaska Pipeline;

The pipelines are designed to bend without leaking in the event of ice keel impingement or the maximum predicted subsidence from permafrost thaw;

The pipelines are coated on the outside and protected with anodes to prevent corrosion; and

The shore transition is buried to protect against storms, ice pile-up, and coastal erosion. The shore transition valve pad is elevated and set back from the shoreline.

A best-available-technology leak detection system is being used during operations to monitor for any potential leaks. The Northstar pipeline incorporates two independent, computational leak detection systems: (1) The Pressure Point Analysis (PPA) system, which detects a sudden loss of pressure in the pipeline; and (2) the mass balance leak detection system, which supplements the PPA. Furthermore, an independent hydrocarbon sensor, the LEOS leak detection system, located between the two pipelines, can detect hydrocarbon vapors and further supplements the other systems.

Intelligent inspection pigs are used during operations to monitor pipe conditions and measure any changes.

The line is constructed with no flanges, valves, or fittings in the subsea section to reduce the likelihood of equipment failure.

During operations, BP conducts aerial forward looking infrared

(FLIR) surveillance of the offshore and onshore pipeline corridors at least once per week (when conditions allow), to detect pipeline leaks.

Pipeline isolation valves are inspected on a regular basis. In addition to FLIR observations/inspections, BP conducts a regular oil pipeline pig inspection program to assess continuing pipeline integrity. The

LEOS Leak Detection System is used continuously to detect under-ice releases during the ice covered period.

The pipelines are also monitored annually to determine any potential sources of damage along the pipeline route. The monitoring work has been conducted in two phases: (1) A helicopter-based reconnaissance of strudel drainage features in early June; and (2) a vessel-based survey program in late July and early August. During the vessel-based surveys, multi-beam, single-beam, and side scan sonar are used. These determine the locations and characteristics of ice gouges and strudel scour depressions in the sea bottom along the pipeline route and at additional selected sites where strudel drainage features have been observed. If strudel scour depressions are identified, additional gravel fill is placed in the open water season to maintain the sea bottom to original pipeline construction depth.

(5) Routine Repair and Maintenance

Various routine repair and maintenance activities have occurred since the construction of Northstar. Examples of some of these activities include completion and repair of the island slope protection berm and well cellar retrofit repairs. Activities associated with these repairs or modifications are reported in the 1999-2004 final comprehensive report (Rodrigues and Williams, 2006) and since 2005 in the various Annual Reports (Rodrigues et al., 2006; Rodrigues and

Richardson, 2007; Aerts and Rodrigues, 2008; Aerts, 2009). Some of these activities, such as repair of the island slope protection berm, were major repairs that involved the use of barges and heavy equipment, while others were smaller-scale repairs involving small pieces of equipment and hand operated tools. The berm surrounding the island is designed to break waves and ice movement before they contact the island work surface and is subjected to regular eroding action from these forces. The berm and sheet pile walls will require regular surveying and maintenance in the future. Potential repair and maintenance activities that are expected to occur at Northstar during the period 2011-2016 include pile driving, traffic, gravel transport, dock construction and maintenance, diving and other activities similar to those that have occurred in the past.

(6) Emergency and Oil Spill Response Training

Emergency and oil spill response training activities are conducted at various times throughout the year at Northstar. Oil spill drill exercises are conducted by ACS during both the ice-covered and open- water periods. During the ice-covered periods, exercises are conducted for containment of oil in water and for detection of oil under ice.

These spill drills have been conducted on mostly bottom-fast ice in an area 200 ft x 200 ft (61 m x 61 m) located just west of the island, using snow machines and ATVs. The spill drill includes the use of various types of equipment to cut ice slots or drill holes through the floating sea ice. Typically, the snow is cleared from the ice surface with a Bobcat loader and snow blower to allow access to the ice. Two portable generators are used to power light plants at the drill site.

The locations and frequency of future spill drills or exercises will vary depending on the condition of the sea ice and training needs.

ACS conducts spill response training activities during the open- water season

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during late July through early October. Vessels used as part of the training typically include Zodiacs, Kiwi Noreens, and Bay-class boats that range in length from 12-45 ft (3.7-13.7 m). Future exercises could include other vessels and equipment.

ARKTOS amphibious emergency escape vehicles are stationed on

Northstar Island. Each ARKTOS is capable of carrying 52 people.

Training exercises with the ARKTOS are conducted monthly during the ice-covered period. ARKTOS training exercises are not conducted during the summer. Equipment and techniques used during oil spill response exercises are continually updated, and some variations relative to the activities described here are to be expected.

(7) Northstar Abandonment

Detailed plans for the decommissioning of Northstar will be prepared near the end of field life, which will not occur during the period requested for these proposed regulations. For additional information on abandonment and decommissioning of the Northstar facility, refer to BP's application (see ADDRESSES).

Northstar Sound Characteristics

During continuing production activities at Northstar, sounds and non-acoustic stimuli will be generated by vehicle traffic, vessel operations, helicopter operations, drilling, and general operations of oil and gas facilities (e.g., generator sounds and gas flaring). The sounds generated from transportation activities will be detectable underwater and/or in air some distance away from the area of activity.

The distance will depend on the nature of the sound source, ambient noise conditions, and the sensitivity of the receptor. Take of marine mammals by Level B harassment incidental to the activities mentioned in this document could occur for the duration of these proposed regulations. The type and significance of the harassment is likely to depend on the species and activity of the animal at the time of reception of the stimulus, as well as the distance from the sound source and the level of the sound relative to ambient conditions.

(1) Construction Sounds

Sounds associated with construction of Seal Island in 1982 were studied and described by Greene (1983a) and summarized in the previous petition for regulations submitted by BP (BPXA, 1999). Underwater and in-air sounds and iceborne vibrations of various activities associated with the final construction phases of Northstar were recorded in the winter of 2000-2002 (Greene et al., 2008). The main purpose of these measurements was to characterize the properties of island construction sounds and to use this information in assessing their possible impacts on wildlife. Activities recorded included ice augering, pumping sea water to flood the ice and build an ice road, a bulldozer plowing snow, a Ditchwitch cutting ice, trucks hauling gravel over an ice road to the island site, a backhoe trenching the sea bottom for a pipeline, and both vibratory and impact sheet pile driving (Greene et al., 2008).

Table 5 in BP's application presents a summary of the levels of construction sounds and vibrations measured around the Northstar prospect.

Ice road construction is difficult to separate into its individual components, as one or more bulldozers and several rolligons normally work concurrently. Of the construction activities reported, those related to ice road construction (bulldozers, augering and pumping) produced the least amount of sound, in all three media. The distance to median background for the strongest one-third octave bands for bulldozers, augering, and pumping was less than 1.24 mi (2 km) for underwater sounds, less than 0.62 mi (1 km) for in-air sounds, and less than 2.5 mi (4 km) for iceborne vibrations (see Table 5 in BP's application). Vibratory sheet pile driving produced the strongest sounds, with broadband underwater levels of 143 dB re 1 [micro]Pa at 328 ft (100 m). Most of the sound energy was in a tone close to 25 Hz.

Distances to background levels of underwater sounds (approximately 1.86 mi [3 km]) were somewhat smaller than expected. Shepard et al. (2001) recorded sound near Northstar in April 2001 during construction and reported that the noisiest conditions occurred during sheet pile installation with a vibrating hammer. BP's estimates were 8-10 dB higher at 492 ft (150 m) and 5-8 dB lower at 1.24 mi (2 km) than the measurements by Shepard et al. (2001). Greene et al. (2008) describes sound levels during impact sheet pile driving. However, satisfactory recordings for this activity were only obtained at one station 2,395 ft

(730 m) from the sheet pile driven into the island. The maximum peak pressure recorded on the hydrophone was 136.1 dB re 1 [micro]Pa and 141.1 dB re 1 [micro]Pa on the geophone (Greene et al., 2008).

(2) Operational Sounds

Drilling operations started in December 2000 and were the first sound-producing activities associated with the operational phase at

Northstar. The four principal operations that occur during drilling are drilling itself, tripping (extracting and lowering the drillstring), cleaning, and well-logging (lowering instruments on a cable down the hole). Drilling activities can be categorized as non-continuous sounds, i.e., they contribute to Northstar sounds intermittently. Other non- continuous sounds are those from heavy equipment operation for snow removal, berm maintenance, and island surface maintenance. Sounds from occasional movements of a ``pig'' through the pipeline may also propagate into the marine or nearshore environment.

Sounds from generators, process operations (e.g., flaring, seawater treatment, oil processing, gas injection), and island lighting are more continuous and contribute to the operational sounds from Northstar.

Drilling and operational sounds underwater, in air, and of ice-borne vibrations were obtained at Northstar Island and are summarized here and in a bit more detail in BP's application (Blackwell et al., 2004b;

Blackwell and Greene, 2006).

Drilling--During the ice covered seasons from 1999 to 2002, drilling sounds were measured and readily identifiable underwater, with a marked increase in received levels at 60-250 Hz and 700-1400 Hz relative to no-drilling times. The higher-frequency peak, which was distinct enough to be used as a drilling ``signature'', was clearly detectible 3.1 mi (5 km) from the drill rig, but had fallen to background values by 5.8 mi (9.4 km). Distances at which background levels were reached were defined as the distance beyond which broadband levels remained constant with increasing distance from the source.

Sound pressure levels of island production with and without drilling activities measured at approximately 1,640 ft (500 m) from Northstar are similar, with most of the sound energy below 100 Hz. The broadband

(10-10,000 Hz) level was approximately 2 dB higher during drilling than without, but relatively low in both cases (99 vs. 97 dB re 1 [micro]Pa;

Blackwell and Greene, 2006).

In air, drilling sounds were not distinguishable from overall island sounds based on spectral characteristics or on broadband levels

(Blackwell et al., 2004b). A similar result was found for recordings from geophones: broadband levels of iceborne vibrations with or without drilling were indistinguishable (Blackwell et al., 2004b). Thus, airborne sounds and iceborne vibrations were not strong enough during drilling to have much influence on overall Northstar sound, in contrast to underwater

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sounds, which were higher during drilling (Blackwell and Greene, 2006).

Richardson et al. (1995b) summarized then-available data by stating that sounds associated with drilling activities vary considerably, depending on the nature of the ongoing operations and the type of drilling platform (island, ship, etc.). Underwater sound associated with drilling from natural barrier islands or an artificial island built mainly of gravel is generally weak and is inaudible at ranges beyond several kilometers. The results from the Northstar monitoring work in more recent years are generally consistent with the earlier evidence.

Other Operational Sounds: Ice-covered Season--Both with and without drilling, underwater broadband levels recorded north of the island during the ice-covered season were similar with and without production

(Blackwell et al., 2004b). Although the broadband underwater levels did not seem to be affected appreciably by production activities, a peak at 125-160 Hz could be related to production. This peak was no longer detectable 3.1 mi (5 km) from the island, either with or without simultaneous drilling (Blackwell et al., 2004b).

Other Operational Sounds: Open-water Season--Underwater and in-air production sounds from Northstar Island were recorded and characterized during nine open-water seasons from 2000 to 2008 (Blackwell and Greene, 2006; Blackwell et al., 2009). Island activity sounds recorded during 2000-2003 included construction of the island, installation of facilities, a large sealift transported by several barges and associated Ocean, River, and Point Class tugs, conversion of power generation from diesel-powered generators to Solar gas turbines, drilling, production, and reconstruction of an underwater berm for protection against ice. From 2003-2008 island activities mainly consisted of production related sounds and maintenance activities of the protection barrier. During the open water season, vessels were the main contributors to the underwater sound field at Northstar (Blackwell and Greene, 2006). Vessel noise is discussed in the next subsection.

During both the construction phase in 2000 and the drilling and production phase, island sounds underwater reached background values at distances of 1.2-2.5 mi (2-4 km; Blackwell and Greene, 2006). For each year, percentile levels of broadband sound (maximum, 95th, 50th, and 5th percentile, and minimum) were computed over the entire field season. The range of broadband levels recorded over 2001-2008 for all percentiles is 80.8-141 dB re 1 [micro]Pa. The maximum levels are mainly determined by the presence of vessels and can be governed by one specific event. The 95th percentile represents the sound level generated at Northstar during 95% of the time. From 2004 to 2008 these levels ranged from 110 to 119.5 dB re 1 [micro]Pa at approximately 0.3 mi (450 m) from Northstar. Much of the variation in received levels was dependent on sea state, which is correlated with wind speed. The lowest sound levels in the time series are indicative of the quietest times in the water near the island and generally correspond to times with low wind speeds. Conversely, times of high wind speed usually correspond to increased broadband levels in the directional seafloor acoustic recorder (DASAR) record (Blackwell et al., 2009). The short-term variability in broadband sound levels in 2008 was higher than in previous years. This was attributed to the presence of a new type of impulsive sound on the records of the near-island DASARs, referred to as ``pops''. Bearings pointed to the northeastern part of Northstar

Island, but to date the source is not known. Pops were broadband in nature, of short duration (approximately 0.05 s), and with received sound pressure levels at the near-island DASAR ranging from 107 to 144 dB re 1 [mu]Pa. This sound was also present on the 2009 records, but the source remains unknown.

Airborne sounds were recorded concurrently with the boat-based recordings in 2000-2003 (Blackwell and Greene, 2006). The strongest broadband airborne sounds were recorded approximately 985 ft (300 m) from Northstar Island in the presence of vessels, and reached 61-62 dBA re 20 [mu]Pa. These values are expressed as A-weighted levels on the scale normally used for in-air sounds. In-air sounds generally reached a minimum 0.6-2.5 mi (1-4 km) from the island, with or without the presence of boats.

(3) Transportation Sounds

Sounds related to winter construction activities of Seal Island in 1982 were reported by Greene (1983a) and information on this topic can be found in BP's 1999 application (BPXA, 1999). During the construction and operation of Northstar Island from 2000 to 2002, underwater sound from vehicles constructing and traveling along the ice road diminished to background levels at distances ranging from 2.9 to 5.9 mi (4.6 to 9.5 km). In-air sound levels of these activities reached background levels at distances ranging from 328-1,969 ft (100-600 m; see Table 5 in BP's application).

Sounds and vibrations from vehicles traveling along an ice road constructed across the grounded sea ice and along Flaxman Island (a barrier Island east of Prudhoe Bay) were recorded in air and within artificially constructed polar bear dens in March 2002 (MacGillivray et al., 2003). Underwater recordings were not made. Sounds from vehicles traveling along the ice road were attenuated strongly by the snow cover of the artificial dens; broadband vehicle traffic noise was reduced by 30-42 dB. Sound also diminished with increasing distance from the station. Most vehicle noise was indistinguishable from background

(ambient) noise at 1,640 ft (500 m), although some vehicles were detectable to more than 1.2 mi (2,000 m). Ground vibrations (measured as velocity) were undetectable for most vehicles at a distance of 328 ft (100 m) but were detectable to 656 ft (200 m) for a H[auml]gglunds tracked vehicle (MacGillivray et al., 2003).

Helicopters were used for personnel and equipment transport to and from Northstar during the unstable ice periods in spring and fall.

Helicopters flying to and from Northstar generally maintain straight- line routes at altitudes of 1,000 ft (300 m) ASL, thereby limiting the received levels at and below the surface. Helicopter sounds contain numerous prominent tones at frequencies up to about 350 Hz, with the strongest measured tone at 20-22 Hz. Received peak sound levels of a

Bell 212 passing over a hydrophone at an altitude of approximately 1,000 ft (300 m), which is the minimum allowed altitude for the

Northstar helicopter under normal operating conditions, varied between 106 and 111 dB re 1 [mu]Pa at 30 and 59 ft (9 and 18 m) water depth

(Greene, 1982, 1985). Harmonics of the main rotor and tail rotor usually dominate the sound from helicopters; however, many additional tones associated with the engines and other rotating parts are sometimes present (Patenaude et al., 2002).

Under calm conditions, rotor and engine sounds are coupled into the water within a 26[deg] cone beneath the aircraft. Some of the sound transmits beyond the immediate area, and some sound enters the water outside the 26[deg] cone when the sea surface is rough. However, scattering and absorption limit lateral propagation in shallow water.

For these reasons, helicopter and fixed-wing aircraft flyovers are not heard underwater for very long, especially when compared to how long they are heard in air as the aircraft approaches, passes and moves away

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from an observer. Tones from helicopter traffic were detected underwater at a horizontal distance approximately 1,476 ft (450 m) from

Northstar, but only during helicopter departures from Northstar

(Blackwell et al., 2009). The duration of the detectable tones, when present, was short (20-50 s), and the received sound levels were weak, sometimes barely detectable. The lack of detectable tones during 65% of the investigated helicopter departures and arrivals supports the importance of the aircraft's path in determining whether tones will be detectable underwater. Helicopter tones were not detectable underwater at the most southern DASAR location approximately 4 mi (6.5 km) north of Northstar.

Principally the crew boat, tugs, and self-propelled barges were the main contributors to the underwater sound field at Northstar during the construction and production periods (Blackwell and Greene, 2006).

Vessel sounds are a concern due to the potential disturbance to marine mammals (Richardson et al., 1995b). Characteristics of underwater sounds from boats and vessels have been reported extensively, including specific measurements near Northstar (Greene and Moore, 1995; Blackwell and Greene, 2006). Broadband source levels for most small ships

(lengths about 180-279 ft [55-85 m]) are approximately 160-180 dB re 1

mu

Pa. Both the crew boat and the tugs produced substantial broadband sound in the 50-2,000 Hz range, which could at least in part be accounted for by propeller cavitation (Ross, 1976). Several tones were also apparent in the vessel sounds, including one at 17.5 Hz, corresponding to the propeller blade rate of Ocean Class tugs. Two tones were identified for the crew boat: one at 52-55 Hz, which corresponds to the blade rate, and one at 22-26 Hz, which corresponds to a harmonic of the shaft rate.

The presence of boats considerably expanded the distances to which

Northstar-related sound was detectable. On days with average levels of background sounds, sounds from tug boats were detectable on offshore

DASAR recordings to at least 13.4 mi (21.5 km) from Northstar

(Blackwell et al., 2009). On other occasions, vessel sounds from crew boat, tugs, and self-propelled barges were often detectable underwater as much as approximately 18.6 mi (30 km) offshore (Blackwell and

Greene, 2006). BP therefore looked into options to reduce vessel use.

During the summer of 2003, a small, diesel-powered hovercraft (Griffon 2000TD) was tested to transport crew and supplies between the mainland and Northstar Island. Acoustic measurements showed that the hovercraft was considerably quieter underwater than similar-sized conventional vessels (Blackwell and Greene, 2005). Received underwater broadband sound levels at 21.3 ft (6.5 m) from the hovercraft reached 133 and 131 dB re 1 [mu]Pa for hydrophone depths 3 ft and 23 ft (1 m and 7 m), respectively. In-air unweighted and A-weighted broadband (10-10,000 Hz) levels reached 104 and 97 dB re 20 [mu]Pa, respectively. Use of the hovercraft for Northstar transport resulted in a decreased number of periods of elevated vessel noise in the acoustic records of the near- island DASARs (Blackwell et al., 2009).

Description of Marine Mammals in the Area of the Specified Activity

The Beaufort Sea supports a diverse assemblage of marine mammals, including: Bowhead, gray, beluga, killer, minke, and humpback whales; harbor porpoises; ringed, ribbon, spotted, and bearded seals; narwhals; polar bears; and walruses. The bowhead and humpback whales and polar bear are listed as ``endangered'' under the Endangered Species Act

(ESA) and as depleted under the MMPA. Certain stocks or populations of gray, beluga, and killer whales and spotted seals are listed as endangered or are proposed for listing under the ESA; however, none of those stocks or populations occur in the proposed activity area. On

December 10, 2010, NMFS published a notice of proposed threatened status for subspecies of the ringed seal (75 FR 77476) and a notice of proposed threatened and not warranted status for subspecies and distinct population segments of the bearded seal (75 FR 77496) in the

Federal Register. Neither of these two ice seal species is considered depleted under the MMPA. Additionally, the ribbon seal is considered a

``species of concern'' under the ESA. Both the walrus and the polar bear are managed by the U.S. Fish and Wildlife Service (USFWS) and are not considered further in this proposed rulemaking.

Of the species mentioned here, the ones that are most likely to occur near the Northstar facility include: bowhead, gray, and beluga whales and ringed, bearded, and spotted seals. Ringed seals are year- round residents in the Beaufort Sea and are anticipated to be the most frequently encountered species in the proposed project area. Bowhead whales are anticipated to be the most frequently encountered cetacean species in the proposed project area; however, their occurrence is not anticipated to be year-round. The most common time for bowheads to occur near Northstar is during the fall migration westward through the

Beaufort Sea, which typically occurs from late August through October each year.

Other marine mammal species that have been observed in the Beaufort

Sea but are uncommon or rarely identified in the project area include harbor porpoise, narwhal, killer, minke, and humpback whales, and ribbon seals. These species could occur in the project area, but each of these species is uncommon or rare in the area and relatively few encounters with these species are expected during BP's activities. The narwhal occurs in Canadian waters and occasionally in the Beaufort Sea, but it is rare there and is not expected to be encountered. There are scattered records of narwhal in Alaskan waters, including reports by subsistence hunters, where the species is considered extralimital

(Reeves et al., 2002). Point Barrow, Alaska, is the approximate northeastern extent of the harbor porpoise's regular range (Suydam and

George, 1992), though there are extralimital records east to the mouth of the Mackenzie River in the Northwest Territories, Canada, and recent sightings in the Beaufort Sea in the vicinity of Prudhoe Bay during surveys in 2007 and 2008 (Christie et al., 2009). Monnett and Treacy

(2005) did not report any harbor porpoise sightings during aerial surveys in the Beaufort Sea from 2002 through 2004. Humpback and minke whales have recently been sighted in the Chukchi Sea but very rarely in the Beaufort Sea. Greene et al. (2007) reported and photographed a humpback whale cow/calf pair east of Barrow near Smith Bay in 2007, which is the first known occurrence of humpbacks in the Beaufort Sea.

Savarese et al. (2009) reported one minke whale sighting in the

Beaufort Sea in 2007 and 2008. Ribbon seals do not normally occur in the Beaufort Sea; however, two ribbon seal sightings were reported during vessel-based activities near Prudhoe Bay in 2008 (Savarese et al., 2009). Due to the rarity of these species in the proposed project area and the remote chance they would be affected by BP's proposed activities at Northstar, these species are not discussed further in these proposed regulations.

BP's application contains information on the status, distribution, seasonal distribution, and abundance of each of the six species under

NMFS jurisdiction likely to be impacted by the proposed activities.

When reviewing the application, NMFS determined that the species descriptions provided by BP correctly characterized the status,

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distribution, seasonal distribution, and abundance of each species.

Please refer to the application for that information (see ADDRESSES).

Additional information can also be found in the NMFS Stock Assessment

Reports (SAR). The 2010 Alaska Marine Mammal SAR is available on the

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

Brief Background on Marine Mammal Hearing

When considering the influence of various kinds of sound on the marine environment, it is necessary to understand that different kinds of marine life are sensitive to different frequencies of sound. Based on available behavioral data, audiograms have been derived using auditory evoked potentials, anatomical modeling, and other data,

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

Low frequency cetaceans (13 species of mysticetes): functional hearing is estimated to occur between approximately 7 Hz and 22 kHz (however, a study by Au et al. (2006) of humpback whale songs indicate that the range may extend to at least 24 kHz);

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

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

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

Pinnipeds in Air: functional hearing is estimated to occur between approximately 75 Hz and 30 kHz.

As mentioned previously in this document, six marine mammal species

(three cetacean and three pinniped species) are likely to occur in the

Northstar facility area. Of the three cetacean species likely to occur in BP's project area, two are classified as low frequency cetaceans

(i.e., bowhead and gray whales) and one is classified as a mid- frequency cetacean (i.e., beluga whales) (Southall et al., 2007).

Underwater audiograms have been obtained using behavioral methods for four species of phocinid seals: the ringed, harbor, harp, and northern elephant seals (reviewed in Richardson et al., 1995b; Kastak and Schusterman, 1998). Below 30-50 kHz, the hearing threshold of phocinids is essentially flat down to at least 1 kHz and ranges between 60 and 85 dB re 1 [mu]Pa. There are few published data on in-water hearing sensitivity of phocid seals below 1 kHz. However, measurements for one harbor seal indicated that, below 1 kHz, its thresholds deteriorated gradually to 96 dB re 1 [mu]Pa at 100 Hz from 80 dB re 1

mu

Pa at 800 Hz and from 67 dB re 1 [mu]Pa at 1,600 Hz (Kastak and

Schusterman, 1998). More recent data suggest that harbor seal hearing at low frequencies may be more sensitive than that and that earlier data were confounded by excessive background noise (Kastelein et al., 2009a,b). If so, harbor seals have considerably better underwater hearing sensitivity at low frequencies than do small odontocetes like belugas (for which the threshold at 100 Hz is about 125 dB). In air, the upper frequency limit of phocid seals is lower (about 20 kHz).

Pinniped call characteristics are relevant when assessing potential masking effects of man-made sounds. In addition, for those species whose hearing has not been tested, call characteristics are useful in assessing the frequency range within which hearing is likely to be most sensitive. The three species of seals present in the study area, all of which are in the phocid seal group, are all most vocal during the spring mating season and much less so during late summer. In each species, the calls are at frequencies from several hundred to several thousand hertz--above the frequency range of the dominant noise components from most of the proposed oil production and operational activities.

Cetacean hearing has been studied in relatively few species and individuals. The auditory sensitivity of bowhead, gray, and other baleen whales has not been measured, but relevant anatomical and behavioral evidence is available. These whales appear to be specialized for low frequency hearing, with some directional hearing ability

(reviewed in Richardson et al., 1995b; Ketten, 2000). Their optimum hearing overlaps broadly with the low frequency range where BP's production activities and associated vessel traffic emit most of their energy.

The beluga whale is one of the better-studied species in terms of its hearing ability. As mentioned earlier, the auditory bandwidth in mid-frequency odontocetes is believed to range from 150 Hz to 160 kHz

(Southall et al., 2007); however, belugas are most sensitive above 10 kHz. They have relatively poor sensitivity at the low frequencies

(reviewed in Richardson et al., 1995b) that dominate the sound from industrial activities and associated vessels. Nonetheless, the noise from strong low frequency sources is detectable by belugas many kilometers away (Richardson and Wursig, 1997). Also, beluga hearing at low frequencies in open-water conditions is apparently somewhat better than in the captive situations where most hearing studies were conducted (Ridgway and Carder, 1995; Au, 1997). If so, low frequency sounds emanating from production activities may be detectable somewhat farther away than previously estimated.

Call characteristics of cetaceans provide some limited information on their hearing abilities, although the auditory range often extends beyond the range of frequencies contained in the calls. Also, understanding the frequencies at which different marine mammal species communicate is relevant for the assessment of potential impacts from manmade sounds. A summary of the call characteristics for bowhead, gray, and beluga whales is provided next. More information is available in BP's application (see ADDRESSES).

Most bowhead calls are tonal, frequency-modulated sounds at frequencies of 50-400 Hz. These calls overlap broadly in frequency with the underwater sounds emitted by many construction and operational activities (Richardson et al., 1995b). Source levels are quite variable, with the stronger calls having source levels up to about 180 dB re 1 [micro]Pa at 1 m. Gray whales make a wide variety of calls at frequencies from Startle responses at received levels of 200-205 dB re 1

micro

Pa and above for two sensitive species, but not for two other species exposed to levels up to 207 dB;

Alarm responses at 177-180 dB for the two sensitive species, and at 186 to 199 dB for other species;

An overall threshold for the above behavioral response at about 180 dB;

An extrapolated threshold of about 161 dB for subtle changes in the behavior of rockfish; and

A return to pre-exposure behaviors within the 20-60 minute exposure period.

In summary, fish often react to sounds, especially strong and/or intermittent sounds of low frequency. Sound pulses at received levels of 160 dB re 1 [micro]Pa may cause subtle changes in behavior. Pulses at levels of 180 dB may cause noticeable changes in behavior (Chapman and Hawkins, 1969; Pearson et al., 1992; Skalski et al., 1992). It also appears that fish often habituate to repeated strong sounds rather rapidly, on time scales of minutes to an hour. However, the habituation does not endure, and resumption of the strong sound source may again elicit disturbance responses from the same fish. Underwater sound levels from Northstar, even during construction, were lower than the response threshold reported by Pearson et al. (1992), and are not likely to result in major effects to fish near Northstar.

The reactions of fish to research vessel sounds have been measured in the field with forward-looking echosounders. Sound produced by a ship varies with aspect and is lowest directly ahead of the ship and highest within butterfly-shaped lobes to the side of the ship (Misund et al., 1996). Because of this directivity, fish that react to ship sounds by swimming in the same direction as the ship may be guided ahead of it (Misund, 1997). Fish in front of a ship that show avoidance reactions may do so at ranges of 164 to 1,148 ft (50 to 350 m; Misund, 1997), though reactions probably will depend on the species of fish. In some instances, fish will likely avoid the ship by swimming away from the path and become relatively concentrated to the side of the ship

(Misund, 1997). Most schools of fish are likely to show avoidance if they are not in the path of the vessel. When the vessel passes over fish, some species, in some cases, show sudden escape responses that include lateral avoidance and/or downward compression of the school

(Misund, 1997). Some fish show no reaction. Avoidance reactions are quite variable and depend on species, life history stage, behavior, time of day, whether the fish have fed, and sound propagation characteristics of the water (Misund, 1997).

Some of the fish species found in the Arctic are prey sources for odontocetes and pinnipeds. A reaction by fish to sounds produced by the operations at Northstar would only be relevant to marine mammals if it caused concentrations of fish to vacate the area. Pressure changes of sufficient magnitude to cause that type of reaction would probably occur only very close to the sound source, if any would occur at all due to the low energy sounds produced by the majority of equipment at

Northstar. 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.

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 drilling and production operations at

Northstar. 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. Some mysticetes, including bowhead whales, feed on concentrations of zooplankton. Some feeding bowhead whales may occur in the Alaskan Beaufort Sea in July and August, and others feed intermittently during their westward migration in September and October (Richardson and Thomson [eds.], 2002; Lowry et al., 2004).

A reaction by zooplankton to sounds produced by the operations at

Northstar would only be relevant to whales if it caused concentrations of zooplankton to scatter. Pressure changes of sufficient magnitude to cause that type of reaction would probably occur only very close to the sound source, if any would occur at all due to the low energy sounds produced by the majority of equipment at Northstar. 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.

Potential Impacts From Ice Road Construction

Ringed seals dig lairs in the sea ice near and around Northstar during the pupping season. There is the potential for ice road construction to impact areas of the ice used by ringed seals to create these lairs and breathing holes. Ice habitat for ringed seal breathing holes and lairs (especially for mothers and pups) is normally associated with pressure ridges or cracks (Smith and Stirling, 1975).

The amount of habitat altered by Northstar ice road construction is minimal compared to the overall habitat available in the region.

Densities of ringed seals on the ice near Northstar during late spring are similar to densities seen elsewhere in the region (Miller et al., 1998b; Link et al., 1999; Moulton et al., 2002, 2005). Ringed seals use multiple breathing holes (Smith and Stirling, 1975; Kelly and

Quakenbush, 1990) and are not expected to be adversely affected by the loss of one to two breathing holes within the thickened ice road.

Ringed seals near Northstar appear to have the ability to open new holes and create new structures throughout the winter, and ringed seal use of landfast ice near Northstar did not appear to be much different than that of ice 1.2-2.2 mi away (2-3.5 km; Williams et al., 2002).

Active seal structures were found within tens of meters of thickened ice (Williams et al., 2006b,c). A few ringed seals occur within areas of artificially thickened ice if cracks that can be exploited by seals form in that thickened ice. Therefore, ice road construction activities are not anticipated to have a major impact on the availability of ice for lairs and breathing holes for ringed seals in the vicinity of

Northstar.

Potential Impacts From an Oil Spill

Oil spill probabilities for the Northstar project have been calculated based on historic oil spill data. Probabilities vary depending on assumptions and method of calculation. A reanalysis of worldwide oil spill data indicates the probability of a large oil spill

(>1,000 barrels) during the lifetime of Northstar is low (S.L. Ross

Environmental Research Ltd., 1998). That report uses standardized units such as well-years and pipeline mile-years to develop oil spill probabilities for the Northstar project. Well-years represent the summed number of years that the various wells will be producing, and mile-years represent the length of pipeline times the amount of time the

Page 39729

pipeline is in service. The calculated probability of a large oil spill takes into account the state-of-the-art engineering and procedures used at Northstar. That probability is far lower than previously-estimated probabilities (23-26%), which were based on Minerals Management Service

(MMS, now the Bureau of Ocean Energy Management [BOEM]), studies of offshore oil field experience in the Gulf of Mexico and California

(USACE, 1998a).

Based on the MMS exposure variable and an estimated production of 158 million barrels of oil, the probability of one or more well blowouts or tank spills >1,000 barrels on Seal Island is 7% throughout the life of the project (approximately 15-20 years; USACE, 1998a). The chance of the maximum estimated well blowout volume (225,000 barrels) being released is very low. Tank spills would likely be contained to the island itself. Based on the MMS exposure variable, there is an estimated 19% probability of one or more offshore pipeline ruptures or leaks releasing 1,000 barrels or more. However, of the 12 pipeline spills in OCS areas of >1,000 barrels from 1964-1992, anchor damage to the pipeline caused 7 spills, hurricane damage caused 2, trawl damage caused 2, and pipeline corrosion caused 1. The Northstar pipeline is buried, and there is minimal boat traffic in the area, therefore eliminating damage from anchors or trawls. With these two events eliminated, the risk of an offshore pipeline spill is reduced to 5%. A second exposure variable, based on the CONCAWE exposure variable (which is a European organization that maintains a database relevant to environment, health, and safety activities associated with the oil industry), indicates there is a 1.6 to 2.4% probability for one or more offshore pipeline ruptures or leaks releasing >1,000 barrels (USACE, 1998a). It should also be noted that production at BP's Northstar facility has declined significantly since it originally began operating nearly 10 years ago. The oil spill assessment conducted in the late 1990s was based on original peak production levels (which was approximately 80,000 barrels/day), not current production levels (which is approximately 18,000 barrels/day; B. Streever, BP Senior

Environmental Studies Advisor, 2011, pers. comm.).

In the unlikely event of an oil spill from the Northstar pipeline, flow through the line can be stopped. There are automated isolation valves at each terminus of pipeline and at the mainland landfall, including along the sales line at Northstar Island, where the pipeline comes onshore, and at Pump Station 1. These would allow isolation of the marine portion of the line at the island and at the shore landing south of the island.

The Northstar pipe wall thickness is approximately 2.8 x greater than that required to contain the maximum operating gas pressure.

Therefore, the probability of a gas pipeline leak is considered to be low. Also, a gas pipeline leak is not considered to be a potential source of an oil spill.

(1) Oil Effects on Seal and Whale Prey

Arctic cod and other fishes are a principal food item for beluga whales and seals in the Beaufort Sea. Anadromous fish are more sensitive to oil when in the marine environment than when in the fresh water environment (Moles et al., 1979). Generally, arctic fish are more sensitive to oil than are temperate species (Rice et al., 1983).

However, fish in the open sea are unlikely to be affected by an oil spill. Fish in shallow nearshore waters could sustain heavy mortality if an oil slick were to remain in the area for several days or longer.

Fish concentrations in shallow nearshore areas that are used as feeding habitat for seals and whales could be unavailable as prey. Because the animals are mobile, effects would be minor during the ice-free period when whales and seals could go to unaffected areas to feed.

Effects of oil on zooplankton as food for bowhead whales were discussed by Richardson ([ed.] 1987). Zooplankton populations in the open sea are unlikely to be depleted by the effects of an oil spill.

Oil concentrations in water under a slick are low and unlikely to have anything but very minor effects on zooplankton. Zooplankton populations in near surface waters could be depleted; however, concentrations of zooplankton in near-surface waters generally are low compared to those in deeper water (Bradstreet et al., 1987; Griffiths et al., 2002).

Some bowheads feed in shallow nearshore waters (Bradstreet et al., 1987; Richardson and Thomson [eds.], 2002). Wave action in nearshore waters could cause high concentrations of oil to be found throughout the water column. Oil slicks in nearshore feeding areas could contaminate food and render the site unusable as a feeding area.

However, bowhead feeding is uncommon along the coast near the Northstar

Development area, and contamination of certain areas would have only a minor impact on bowhead feeding. In the Beaufort Sea, Camden Bay and

Point Barrow are more common feeding grounds for bowhead whales.

Additionally, gray whales do not commonly feed in the Beaufort Sea and are rarely seen near the Northstar Development area.

Effects of oil spills on zooplankton as food for seals would be similar to those described above for bowhead whales. Effects would be restricted to nearshore waters. During the ice-free period, effects on seal feeding would be minor.

Bearded seals consume benthic animals. Wave action in nearshore waters could cause oil to reach the bottom through adherence to suspended sediments (Sanders et al., 1990). There could be mortality of benthic animals and elimination of some benthic feeding habitat. During the ice-free period, effects on seal feeding would be minor.

Effects on availability of feeding habitat would be restricted to shallow nearshore waters. During the ice-free period, seals and whales could find alternate feeding habitats.

The ringed seal is the only marine mammal present near Northstar in significant numbers during the winter. An oil spill in shallow waters could affect habitat availability for ringed seals during winter. The oil could kill ringed seal food and/or drive away mobile species such as the arctic cod. Effects of an oil spill on food supply and habitat would be locally significant for ringed seals in shallow nearshore waters in the immediate vicinity of the spill and oil slick in winter.

Effects of an oil spill on marine mammal foods and habitat under other circumstances are expected to be minor.

(2) Oil Effects on Habitat Availability

The subtidal marine plants and animals associated with the Boulder

Patch community of Stefansson Sound are not likely to be affected directly by an oil spill from Northstar Island, seaward of the barrier islands and farther west. The only type of oil that could reach the subtidal organisms (located in 16 to 33 ft [5 to 10 m] of water) would be highly dispersed oil created by heavy wave action and vertical mixing. Such oil has no measurable toxicity (MMS, 1996). The amount and toxicity of oil reaching the subtidal marine community is expected to be so low as to have no measurable effect. However, oil spilled under the ice during winter, if it reached the relevant habitat, could act to reduce the amount of light available to the kelp species and other organisms directly beneath the spill. This could be an indirect effect of a spill. Due to the highly variable winter lighting conditions, any reduction in light penetration resulting from an oil spill would not be expected to have a

Page 39730

significant impact on the growth of the kelp communities.

Depending on the timing of a spill, planktonic larval forms of organisms in arctic kelp communities such as annelids, mollusks, and crustaceans may be affected by floating oil. The contact may occur anywhere near the surface of the water column (MMS, 1996). Due to their wide distribution, large numbers, and rapid rate of regeneration, the recovery of marine invertebrate populations is expected to occur soon after the surface oil passes. Spill response activities are not likely to disturb the prey items of whales or seals sufficiently to cause more than minor effects. Additionally, the likelihood of an oil spill is expected to be very low.

In conclusion, NMFS has preliminarily determined that BP's proposed operation of the Northstar Development area is not expected to have any habitat-related effects that could cause significant or long-term consequences for individual marine mammals or on the food sources that they utilize.

Proposed Mitigation

In order to issue an incidental take authorization (ITA) under section 101(a)(5)(A) of the MMPA, NMFS must, where applicable, set forth the permissible methods of taking pursuant to such activity, and other means of effecting the least practicable adverse 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 subsistence uses (where relevant).

As part of its application, BP proposed several mitigation measures in order to ensure the least practicable adverse impact on marine mammal species that may occur in the proposed project area. BP proposed different mitigation measures for the ice-covered season and for the open-water season. The proposed mitigation measures are described fully in BP's application (see ADDRESSES) and summarized here.

Ice-Covered Season Proposed Mitigation Measures

In order to reduce impacts to ringed seal construction of birth lairs, BP must begin winter construction activities (e.g., ice road construction) on the sea ice as early as possible once weather and ice conditions permit such activities. Any ice road or other construction activities that are initiated after March 1 in previously undisturbed areas in waters deeper than 10 ft (3 m) must be surveyed, using trained dogs, in order to identify and avoid ringed seal structures by a minimum of 492 ft (150 m). If dog surveys are conducted, trained dogs shall search all floating sea ice for any ringed seal structures. Those surveys shall be done prior to the new proposed activity on the floating sea ice to provide information needed to prevent injury or mortality of young seals. Additionally, after March 1 of each year, activities should avoid, to the greatest extent practicable, disturbance of any located seal structure. It should be noted that since 2001, none of BP's activities took place after March 1 in previously undisturbed areas during late winter, so no on-ice searches were conducted.

Open-Water Season Proposed Mitigation Measures

All non-essential boat, hovercraft, barge, and air traffic shall be scheduled to avoid periods when whales (especially bowhead whales) are migrating through the area. Helicopter flights to support Northstar activities shall be limited to a corridor from Seal Island to the mainland, and, except when limited by weather or personnel safety, shall maintain a minimum altitude of 1,000 ft (305 m), except during takeoff and landing.

Impact hammering activities may occur at any time of year to repair sheet pile or dock damage due to ice impingement. Impact hammering is most likely to occur during the ice-covered season or break-up period and would not be scheduled during the fall bowhead migration. However, if such activities were to occur during the open-water or broken ice season, certain mitigation measures that are described here are proposed to be required of BP. Based on studies by Blackwell et al.

(2004a), it is predicted that only impact driving of sheet piles or pipes that are in the water (i.e., those on the dock) could produce received levels of 190 dB re 1 [mu]Pa (rms) and then only in immediate proximity to the pile. The impact pipe driving in June and July 2000 did not produce received levels as high as 180 dB re 1 [mu]Pa (rms) at any location in the water. This was attributable to attenuation by the gravel and sheet pile walls (Blackwell et al., 2004a). BP anticipates that received levels for any pile driving that might occur within the sheet pile walls of the island in the future would also be less than 180 dB (rms) at all locations in the water around the island. If impact pile driving were planned in areas outside the sheet pile walls, it is possible that received levels underwater might exceed the 180 dB re 1

mu

Pa (rms) level.

NMFS has established acoustic thresholds that identify the received sound levels above which hearing impairment or other injury could potentially occur, which are 180 and 190 dB re 1 [mu]Pa (rms) for cetaceans and pinnipeds, respectively (NMFS, 1995, 2000). The established 180- and 190-dB re 1 [mu]Pa (rms) criteria are the received levels above which, in the view of a panel of bioacoustics specialists convened by NMFS before additional TTS measurements for marine mammals became available, one could not be certain that there would be no injurious effects, auditory or otherwise, to marine mammals. To prevent or at least minimize exposure to sound levels that might cause hearing impairment, a safety zone shall be established and monitored for the presence of seals and whales. Establishment of the safety zone of any source predicted to result in received levels underwater above 180 dB

(rms) will be analyzed using existing data collected in the waters of the Northstar facility (see the ``Proposed Monitoring and Reporting'' section later in this document or BP's application).

If observations and mitigation are required, a protected species observer stationed at an appropriate viewing location on the island will conduct watches commencing 30 minutes prior to the onset of impact hammering or other identified activity. The ``Proposed Monitoring and

Reporting'' section later in this document contains a description of the observer program. If pinnipeds are seen within the 190 dB re 1

mu

Pa radius (the ``safety zone''), then operations shall shut down or reduce SPLs sufficiently to ensure that received SPLs do not exceed those prescribed here. If whales are observed within the 180 dB re 1

mu

Pa (rms) radius, operations shall shut down or reduce SPLs sufficiently to ensure that received SPLs do not exceed those prescribed here. The shutdown or reduced SPL shall be maintained until such time as the observed marine mammal(s) has been seen to have left the applicable safety zone or until 15 minutes have elapsed in the case of a pinniped or odontocete or 30 minutes in the case of a mysticete without resighting, whichever occurs sooner.

Should any new drilling into oil-bearing strata be required during the effective period of these regulations, the drilling shall not take place during either open-water or spring-time broken ice conditions.

Oil Spill Contingency Plan

The taking by harassment, injury, or mortality of any marine mammal species incidental to an oil spill is

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prohibited. However, in the unlikely event of an oil spill, BP expects to be able to contain oil through its oil spill response and cleanup protocols. An oil spill prevention and contingency response plan was developed and approved by the Alaska Department of Environmental

Conservation, U.S. Department of Transportation, U.S. Coast Guard, and

BOEM (formerly MMS). The plan has been amended several times since its initial approval, with the last revision occurring in July 2010. Major changes since 1999 include the following: seasonal drilling restrictions from June 1 to July 20 and from October 1 until ice becomes 18 in (46 cm) thick; changes to the response planning standard for a well blowout as a result of reductions in well production rates; and deletion of ice auguring for monitoring potential sub-sea oil pipeline leaks during winter following demonstration of the LEOS leak detection system. Future changes to the response planning standards may be expected in response to declines in well production rates and pipeline throughput. The full plan can be viewed on the Internet at: http://www.nmfs.noaa.gov/pr/permits/incidental.htm.

The plan consists of five parts. A short summary of the information contained in each part of the plan follows next. For more details, please refer to the plan itself.

Part 1 contains the Response Action Plan, which provides initial emergency response actions and oil spill response scenarios. The

Response Action Plan lays out who is to be notified in the case of a spill and how many people need to be on hand and for how long depending on the size and type of spill. It also outlines different deployment strategies, which include the use of vessels, helicopters, fixed-wing aircraft, vehicles, heavy all-terrain vehicles, and air boats, and during which seasons these strategies could be used. Several response scenarios and strategies were developed in accordance with the Alaska

Administrative Code (AAC). They describe equipment, personnel, and strategies that could be used to respond to an oil spill. It should be noted that the scenarios are for illustration only and assume conditions only for the purposes of describing general procedures, strategies, tactics, and selected operational capabilities. This part of the plan discusses oil spill scenarios and response strategies, including: An oil storage tank rupture; a well blowout under typical summer conditions; a well blowout under typical winter conditions; a crude oil transmission pipeline release; a well blowout during typical spring conditions; a crude oil transmission pipeline rupture during spring break-up; a crude oil transmission pipeline rupture during summer; a crude oil transmission pipeline rupture during fall; and a crude oil transmission pipeline rupture during winter.

Part 2 contains the Prevention Plan, which describes prevention measures to be implemented by facility personnel and inspection and maintenance programs. Personnel who handle oil equipment receive training in general North Slope work procedures, spill prevention, environmental protection awareness, safety, and site-specific orientation. Personnel also receive training in oil spill notification, oil spill source control, and hazardous waste operations and emergency response safety. This section of the plan also outlines fuel transfer procedures, leak detection, monitoring, and operating requirements for crude oil transmission pipelines, and management of oil storage tanks, including inspections and protection devices. This section also discusses the possibilities of corrosion and the monitoring that is conducted to manage the corrosion control programs. This section of the plan also contains a table outlining different types, causes, and sizes of spills and the actions that are taken and in place to prevent such potential discharges. Another table in this section outlines the types of inspections that occur on daily, weekly, monthly, and annual schedules at Northstar to ensure the equipment is still functioning properly and that leaks are not occurring.

Part 3 of the plan contains Supplemental Information. Part 3 provides background information on the facility, including descriptions of the facility, the receiving environment for potential spills, the incident command system, maximum response operating limitations, response resources (personnel and equipment), response training and drills, and protection of environmentally sensitive areas. The receiving environments include oil in open-water, in water and ice during the break-up or freeze-up periods, and on ice. In conditions up to approximately 30% ice, the trajectory of spilled oil would be based on the winds and currents at Northstar. Assuming a 10-knot wind from the northeast, oil spilled at Northstar could reach the barrier island shore of Long Island and if not contained, oil moving inland through the barrier island cuts could reach the Kuparuk River Delta. Oil trapped under a floating solid ice cover would rise and gather in pools or lenses at the bottom of the ice sheet and may become trapped or entrained as new ice grows beneath the oil. Based on the very slow moving currents under the ice near Northstar, oil is unlikely to spread beyond the initial point of contact. During freeze-up, the oil will most likely be entrained in the solidifying grease ice and slush present on the water surface prior to forming an ice sheet. Storm winds at this time often break up and disperse the newly forming ice, leaving the oil to spread temporarily in an open water condition until it becomes incorporated in the next freezing cycle. At break-up, ice concentrations are highly variable from hour to hour and over short distances. In high ice concentrations, oil spreading is reduced and the oil is partially contained by the ice. As the ice cover loosens, more oil could escape into larger openings as the floes move apart.

Eventually, as the ice concentration decreases, the oil on the water surface behaves essentially as an open water spill, with localized patches being temporarily trapped by wind against individual floes. Oil present on the surface of individual floes will move with the ice as it responds to winds and nearshore currents. The spreading of oil on ice is similar to spreading of oil on land or snow. The rate is controlled by the density and viscosity of the oil, and the final contaminated area is dictated by the surface roughness of the ice. As the ice becomes rougher, the oil pools get smaller and thicker. Oil spilled on ice spreads much more slowly than on water and covers a smaller final area. As a result, slicks on stable solid ice tend to be much thicker than equivalent slicks on water. The effective containment provided by even a minimal degree of ice roughness (inches) translates to far less cleanup time with the need for fewer resources than would be needed to deal with the equivalent spill on open water. In the Supplemental

Information section of the plan, a description of the different environments (e.g., open-water, freeze-up, etc.) is provided, including when those conditions occur and the types of ice thickness that are typical during each season.

The command system, which is described in Part 3, is compatible with the Alaska Regional Response Team Unified Plan and is based on the

National Incident Management System. According to the plan, oil spill removal during the freeze-up or break-up seasons can be greatly enhanced by in situ burning. The ice provides containment, increasing the encounter rate and concentrating the oil for burning and recovery.

The consensus of research on

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spill response in broken ice conditions is that in situ burning is an effective response technique, with removal rates exceeding 85 percent in many situations (Shell et al., 1983; SL Ross, 1983; SL Ross and DF

Dickins, 1987; Singsaas et al., 1994). A considerable amount of research has demonstrated in situ burning in broken ice. The research includes several smaller-scale field and tank tests (SL Ross et al., 2003; Shell et al., 1983; Brown and Goodman, 1986; Buist and Dickins, 1987; Smith and Diaz, 1987; Bech et al., 1993; Gu[eacute]nette and

Wighus, 1996) and one large field test (Singsaas et al., 1994). Most of the tests involved large volumes of oil placed in a static test field of broken ice, resulting in substantial slick thicknesses for ignition.

The few tests in unrestricted ice fields or in dynamic ice have indicated that the efficacy of in situ burning is sensitive to ice concentration and dynamics and thus the tendency for the ice floes to naturally contain the oil, the thickness (or coverage) of oil in leads between floes, and the presence or absence of brash (created when larger ice features interact or degrade) or frazil (``soupy'' mixture of very small ice particles that form as seawater freezes) ice which can absorb the oil. Oil spilled on solid ice or among broken ice in concentrations equal to or greater than 6-tenths has a high probability of becoming naturally contained in thicknesses sufficient for combustion. Field experience has shown that it is the small ice pieces

(e.g., the brash and frazil, or slush, ice) that accumulate with the oil against the edges of larger ice features (floes) and control the concentration (e.g., thickness) of oil in an area, and control the rate at which the oil subsequently thins and spreads. The plan contains a summary discussion on the current state of understanding the scientific principles and physical processes involved for in situ burning of oil on melt pools during the ice melt phase in June or on water between floes during the break-up period in July, based on SL Ross et al.

(2003). Further discussion also covers in situ burning of thinner slicks in mobile broken ice comprised of brash or frazil ice during the freeze-up shoulder season in October. Please refer to the plan for these discussions.

Part 4 discusses Best Available Technology (BAT). This section provides a rationale for the prevention technology in place at the facility and a determination of whether or not it is the best available technology. The plan identifies two methods for regaining well control once an incident has escalated to a surface blowout scenario as described in Part 1 of the plan. The two methods are: Well-capping and relief well drilling. BP investigations indicate that well-capping constitutes the BAT for source control of a blowout. Well-capping response operations are highly dependent on the severity of the well control situation. BP has the ability to move specialized personnel and equipment, e.g., capping stack or cutting tools, to North Slope locations upon declaration of a well control event. The materials to execute control (e.g., junk shots, hot tapping, freezing, or crimping), are small enough that they can be quickly made available to remote locations, even by aircraft, as necessary. BP has an inventory of well control firefighting equipment permanently warehoused on the North

Slope. This equipment includes two 6,000 gallons per minute (gpm) fire pumps, associated piping, lighting, transfer pumps, Athey wagons, specialized nozzles, and fire monitor shacks. Maintaining this equipment on the North Slope minimizes the time to mobilize and transport well control response equipment in an actual blowout event.

Relief well drilling technology is compatible to North Slope drilling operations although it may be sensitive to both the well location and well types; however, it can be a timely process. Onshore North Slope relief well durations are often estimated in the 40- to 90-day range.

While BP has determined that well capping constitutes BAT for well source control, BP has deemed it prudent to also activate a separate team to pursue a relief well plan parallel to and independent of the primary well capping plan.

The pipeline source control procedures, required by the AAC, involve the placement of automatic shutdown valves at each terminus and at the shore crossing to stop the flow of oil or product/gas into the

Northstar pipelines. Additionally, the oil pipeline across the

Putuligayuk River includes a manual valve on both sides of the river.

There are two technology options for the valves: Automatic ball valves and automatic gate valves. Both valve options, when installed in new condition, are similar in terms of availability, transferability, cost, compatibility, and feasibility. In terms of effectiveness, ball valves typically have slightly faster closure times than gate valves. For

Northstar, automatic ball valves (block and bleed type) are used. As required by 18 AAC 75.055(b), the flow of oil or product/gas can be completely stopped by these valves within one hour after a discharge has been detected. The valve closure time for these types of valves is usually on the order of 2 to 3 minutes.

Part 5 outlines the Response Planning Standard, which provides calculations of the applicable response planning standards for

Northstar, including a detailed basis for the calculation reductions to be applied to the response planning standards.

Mitigation Conclusions

NMFS has carefully evaluated the applicant'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 adverse impact on the affected marine mammal species and stocks and their habitat. Our evaluation of potential measures included consideration of the following factors in relation to one another:

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

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

The practicability of the measure for applicant implementation.

Based on our evaluation of the applicant's proposed measures, NMFS has preliminarily determined that the mitigation measures proposed above provide the means of effecting the least practicable adverse impact on marine mammal 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 is discussed later in this document (see ``Impact on Availability of Affected Species or

Stock for Taking for Subsistence Uses'' section).

The proposed rule comment period will afford the public an opportunity to submit recommendations, views, and/or concerns regarding this action and the proposed mitigation measures. While NMFS has determined preliminarily that the proposed mitigation measures presented in this document will effect the least practicable adverse impact on the affected species or stocks and their habitat, NMFS will consider all public comments to help inform our final decision.

Consequently, the proposed mitigation measures may be refined, modified, removed, or added to prior to the issuance of the final rule based on public comments received, and where appropriate, further analysis of any additional mitigation measures.

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Proposed Monitoring and Reporting

In order to issue an ITA for an activity, section 101(a)(5)(A) of the MMPA states that NMFS must, where applicable, set forth

``requirements pertaining to the monitoring and reporting of such taking''. The MMPA implementing regulations at 50 CFR 216.104 (a)(13) indicate that requests for ITAs must include the suggested means of accomplishing the necessary monitoring and reporting that will result in increased knowledge of the species and of the level of taking or impacts on populations of marine mammals that are expected to be present in the proposed action area.

The monitoring program proposed by BP in its application and described here is based on the continuation of previous monitoring conducted at Northstar. Information on previous monitoring can be found in the ``Previous Activities and Monitoring'' section found later in this document. The proposed monitoring program may be modified or supplemented based on comments or new information received from the public during the public comment period or from the peer review panel

(see the ``Monitoring Plan Peer Review'' section later in this document).

The monitoring proposed by BP focuses on ringed seals and bowhead whales, as they are the most prevalent species found in the Northstar

Development area. No monitoring is proposed specifically for bearded or spotted seals or for gray or beluga whales, as their occurrence near

Northstar is limited. Few, if any, observations of these species were made during the intensive monitoring from 1999 to 2004. However, if sightings of these (or other) species are made, those observations will be included in the monitoring reports (described later in this document) that will be prepared.

Annual Monitoring Plans

BP proposes to continue the long-term observer program, conducted by island personnel, of ringed seals during the spring and summer. This program is intended to assess the continued long-term stability of ringed seal abundance and habitat use near Northstar as indexed by counts obtained on a regular and long-term basis. The proposed approach is to continue the Northstar seal count that is conducted during the period May 15-July 15 each year from the 108 ft (33 m) high process module by Northstar staff following a standardized protocol since 2005.

Counts are made on a daily basis (weather permitting), between 11:00- 19:00, in an area of approximately 3,117 ft (950 m) around the island, for a duration of approximately 15 minutes. Counts will only be made during periods with visibility of 0.62 mi (1 km) or more and with a cloud ceiling of more than 295 ft (90 m).

BP proposes to continue monitoring the bowhead migration in 2011 and subsequent years for approximately 30 days each September through the recording of bowhead calls. BP proposes to deploy a Directional

Autonomous Seafloor Acoustic Recorder (DASAR; Greene et al., 2004) or similar recorder about 9.3 mi (15 km) north of Northstar, consistent with a location used in past years (as far as conditions allow). The data of the offshore recorder can provide information on the total number of calls detected, the temporal pattern of calling during the recording period, possibly the bearing to calls, and call types. These data can be compared with corresponding data from the same site in previous years. If substantially higher or lower numbers of calls are recorded than were recorded at that site in previous years, further analyses and additional monitoring will be considered in consultation with NMFS and North Slope Borough (NSB) representatives. A second

DASAR, or similar recorder, will be deployed at the same location to provide a reasonable level of redundancy.

In addition to the DASAR already mentioned, BP proposes to install an acoustic recorder about 1,476 ft (450 m) north of Northstar, in the same area where sounds have been recorded since 2001. This recorder will be installed for approximately 30 days each September, corresponding with the deployment of the offshore DASAR (or similar recorder). The near-island recorder will be used to record and quantify sound levels emanating from Northstar. If island sounds are found to be significantly stronger or more variable than in the past, and if it is expected that the stronger sounds will continue in subsequent years, then further consultation with NMFS and NSB representatives will occur to determine if more analyses or changes in monitoring strategy are appropriate. A second acoustic recorder will be deployed to provide a reasonable level of redundancy.

Contingency Monitoring Plans

If BP needs to conduct an activity (i.e., pile driving) capable of producing pulsed underwater sound with levels >= 180 or >= 190 dB re 1

micro

Pa (rms) at locations where whales or seals could be exposed, BP proposes to monitor safety zones defined by those levels. [The safety zones were described in the ``Proposed Mitigation'' section earlier in this document.] One or more on-island observers, as necessary to scan the area of concern, will be stationed at location(s) providing an unobstructed view of the predicted safety zone. The observer(s) will scan the safety zone continuously for marine mammals for 30 minutes prior to the operation of the sound source. Observations will continue during all periods of operation. If whales and seals are detected within the (respective) 180 or 190 dB distances, a shutdown or other appropriate mitigation measure (as described earlier in this document) shall be implemented. The sound source will be allowed to operate again when the marine mammals are observed to leave the safety zone or until 15 minutes have elapsed in the case of a pinniped or odontocete or 30 minutes in the case of a mysticete without resighting, whichever occurs sooner. The observer will record the: (1) Species and numbers of marine mammals seen within the 180 or 190 dB zones; (2) bearing and distance of the marine mammals from the observation point; and (3) behavior of marine mammals and any indication of disturbance reactions to the monitored activity.

If BP initiates significant on-ice activities (e.g., construction of new ice roads, trenching for pipeline repair, or projects of similar magnitude) in previously undisturbed areas after March 1, trained dogs, or a comparable method, will be used to search for seal structures. If such activities do occur after March 1, a follow-up assessment must be conducted in May of that year to determine the fate of all seal structures located during the March monitoring. This monitoring must be conducted by a qualified biological researcher approved in advance by

NMFS after a review of the observer's qualifications.

BP will conduct acoustic measurements to document sound levels, characteristics, and transmissions of airborne sounds with expected source levels of 90 dBA or greater created by on-ice activity at

Northstar that have not been measured in previous years. In addition,

BP will conduct acoustic measurements to document sound levels, characteristics, and transmissions of airborne sounds for sources on

Northstar Island with expected received levels at the water's edge that exceed 90 dBA that have not been measured in previous years. These data will be collected in order to assist in the development of future monitoring and mitigation measures.

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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 established an independent peer review panel to review BP's proposed monitoring plan associated with the MMPA application for these proposed regulations. The panel met in early March 2011. After completion of the peer review, NMFS will consider all recommendations made by the panel, incorporate appropriate changes into the monitoring requirements of the final rule and subsequent LOAs, and publish the panel's findings and recommendations in the final rule.

Reporting Measures

An annual report on marine mammal monitoring and mitigation will be submitted to NMFS, Office of Protected Resources, and NMFS, Alaska

Regional Office, on June 1 of each year. The first report will cover the period from the effective date of the LOA through October 31, 2011.

Subsequent reports will cover activities from November 1 of one year through October 31 of the following year. Ending each annual report with October 31 coincides with the end of the fall bowhead whale migration westward through the Beaufort Sea.

The annual reports will provide summaries of BP's Northstar activities. These summaries will include the following: (1) Dates and locations of ice-road construction; (2) on-ice activities; (3) vessel/ hovercraft operations; (4) oil spills; (5) emergency training; and (6) major repair or maintenance activities that might alter the ambient sounds in a way that might have detectable effects on marine mammals, principally ringed seals and bowhead whales. The annual reports will also provide details of ringed seal and bowhead whale monitoring, the monitoring of Northstar sound via the nearshore DASAR, descriptions of any observed reactions, and documentation concerning any apparent effects on accessibility of marine mammals to subsistence hunters.

If specific mitigation and monitoring are required for activities on the sea ice initiated after March 1 (requiring searches with dogs for lairs), during the operation of strong sound sources (requiring visual observations and shutdown procedures), or for the use of new sound sources that have not previously been measured, then a preliminary summary of the activity, method of monitoring, and preliminary results will be submitted within 90 days after the cessation of that activity. The complete description of methods, results, and discussion will be submitted as part of the annual report.

In addition to annual reports, BP proposes to submit a draft comprehensive report to NMFS, Office of Protected Resources, and NMFS,

Alaska Regional Office, no later than 240 days prior to the expiration of these regulations. This comprehensive technical report will provide full documentation of methods, results, and interpretation of all monitoring during the first four and a quarter years of the LOA. Before acceptance by NMFS as a final comprehensive report, the draft comprehensive report will be subject to review and modification by NMFS scientists.

Any observations concerning possible injuries, mortality, or an unusual marine mammal mortality event will be transmitted to NMFS,

Office of Protected Resources, and the Alaska Stranding and

Disentanglement Program, within 48 hours of the discovery. At a minimum, reported information should include: (1) The time, date, and location (latitude/longitude) of the animal(s); (2) the species identification or description of the animal(s); (3) the fate of the animal(s), if known; and (4) photographs or video footage of the animal

(if equipment is available).

Adaptive Management

The final regulations governing the take of marine mammals incidental to operation of the Northstar facility in the U.S. Beaufort

Sea will contain an adaptive management component. In accordance with 50 CFR 216.105(c), regulations for the proposed activity must be based on the best available information. As new information is developed, through monitoring, reporting, or research, the regulations may be modified, in whole or in part, after notice and opportunity for public review. The use of adaptive management will allow NMFS to consider new information from different sources to determine if mitigation or monitoring measures should be modified (including additions or deletions) if new data suggest that such modifications are appropriate for subsequent LOAs.

The following are some of the possible sources of applicable data:

Results from BP's monitoring from the previous year;

Results from general marine mammal and sound research; or

Any information which reveals that marine mammals may have been taken in a manner, extent or number not authorized by these regulations or subsequent LOAs.

If, during the effective dates of the regulations, new information is presented from monitoring, reporting, or research, these regulations may be modified, in whole, or in part after notice and opportunity of public review, as allowed for in 50 CFR 216.105(c). In addition, LOAs shall be withdrawn or suspended if, after notice and opportunity for public comment, the Assistant Administrator finds, among other things, the regulations are not being substantially complied with or the taking allowed is having more than a negligible impact on the species or stock or an unmitigable adverse impact on the availability of marine mammal species or stocks for taking for subsistence uses, as allowed for in 50

CFR 216.106(e). That is, should substantial changes in marine mammal populations in the project area occur or monitoring and reporting show that operation of the Northstar facility is having more than a negligible impact on marine mammals or an unmitigable adverse impact on the availability of marine mammal species or stocks for taking for subsistence uses, then NMFS reserves the right to modify the regulations and/or withdraw or suspend a LOA after public review.

Previous Activities and Monitoring

The ``Background on the Northstar Development Facility'' section earlier in this document discussed activities that have occurred at

Northstar since construction began in the winter of 1999/2000.

Activities that occurred at Northstar under the current regulations

(valid April 6, 2006, through April 6, 2011) include transportation

(e.g., helicopter, hovercraft, tracked vehicles, and vessels), production activities (e.g., power generation, pipe driving, etc.), construction and maintenance activities, and monitoring programs.

Under those regulations and annual LOAs, BP has been conducting marine mammal monitoring within the action area to satisfy monitoring requirements set forth in MMPA authorizations. The monitoring programs have focused mainly on bowhead whales and ringed seals, as they are the two most common

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marine mammal species found in the Northstar Development area.

Monitoring conducted by BP during this time period included: (1)

Underwater and in-air noise measurements; (2) monitoring of ringed seal lairs; (3) monitoring of hauled out ringed seals in the spring and summer months; and (4) acoustic monitoring of the bowhead whale migration. Additionally, although it was not a requirement of the regulations or associated LOAs, BP has also incorporated work done by

Michael Galginaitis. Since 2001, Galginaitis has observed and characterized the fall bowhead whale hunts at Cross Island.

As required by the regulations and annual LOAs, BP has submitted annual reports, which describe the activities and monitoring that occurred at Northstar. BP also submitted a draft comprehensive report, covering the period 2005-2009. The comprehensive report concentrates on

BP's Northstar activities and associated marine mammal and acoustic monitoring projects from 2005-2009. However, monitoring work prior to 2004 is summarized in that report, and activities in 2010 at Northstar were described as well. The annual reports and draft comprehensive report (Richardson [ed.], 2010) are available on the Internet at: http://www.nmfs.noaa.gov/pr/permits/incidental.htm#applications. A summary of the monitoring can be found here and elsewhere in this document. This section summarizes some of the key objectives and findings; however, specific results and findings of some of the monitoring work that has been conducted at Northstar over the past decade are also described in sections throughout this document.

Prior to the start of construction (1997-1999) and during the first few years of Northstar construction and operation (2000-2002), BP conducted aerial surveys to study the distribution and abundance of seals around Northstar. In addition to aerial surveys, specially- trained dogs were also used to locate seal lairs during the ice-covered seasons of 1999-2000 and 2000-2001. It was determined that such intensive monitoring was not required after 2002; however, BP continued to observe and count seals near Northstar in order to determine if seals continued to use the area, and, if so, if that usage was similar to that found in previous years. The current monitoring consists of someone making counts from a platform between May 15 and July 15 each year, although there is some variation in the number of days observations are made during that period from year-to-year. Counts ranged from a low of three seals counted during 57 observation days in 2007 to a high of 811 seals counted during 61 observation days in 2009

(Richardson [ed.], 2010). Based on the counts that have been conducted, ringed seals continue to haul out around Northstar.

The LOAs also contained requirements to conduct underwater measurements of sounds produced by Northstar-related industrial activities. To obtain these measurements, BP deployed DASARs both near and offshore of Northstar. The exact distances and configurations are contained in Richardson [ed.] (2010). Median levels of sound were found to be low offshore of Northstar (95.4-103.1 dB re 1 [micro]Pa when measured 9.2 mi [14.9 km] away). Also, industrial sounds were found to contribute less of the sound in the 10-450 Hz band during 2005-2009 than it did during the period of 2001-2004.

Since 2001, BP has also been conducting acoustic monitoring to study the fall westward migration of bowhead whales through the

Beaufort Sea and to determine whether or not sounds from Northstar are affecting that migration. The DASARs are also used for this monitoring effort. BP has studied the rate of calls per year and has also worked to localize the calls. Some of the key findings from this work showed that in 8 out of 9 seasons during the 2001-2009 period, bearings to whale calls detected at the same DASAR site 9.2 mi (14.9 km) offshore of Northstar were predominantly to the northeast or east-northeast of that location. Additionally, analysis of the 2008 data demonstrated that bowhead whale calls are directional, which may help to explain why fewer calls are detected west of Northstar than to the east (Richardson

ed.

, 2010). In the comprehensive report (Richardson [ed.], 2010), BP compared calls from 2009 with those from 2001-2004 to try and draw conclusions about effects on the distribution of calling bowheads. BP found that from 2001-2004, the southern edge of the distribution of bowhead calls tended to be slightly but statistically significantly farther offshore when the underwater sound level near Northstar increased above baseline values. For the 2009 data, BP was unable to conclusively identify one specific relationship between offshore distances of bowhead calls and industrial sound.

The annual reports and comprehensive report (Richardson [ed.], 2010) also contain information on the fall Nuiqsut bowhead whale hunts.

The information contained in these reports show that during 2005-2009, the whalers struck 3 or 4 whales (of a quota of 4) in all years except 2005 (only one whale struck and landed). The whalers did not attribute the poor harvest in 2005 to activities at Northstar. That year, there was severe local ice and very poor weather. There was some vessel interference; however, none of that was with vessels at or conducting activities for Northstar. Sealing activities were not common near the

Northstar site prior to its construction, and they are not common there now. Most sealing occurs more than 20 mi (32 km) from Northstar.

During the period of validity of the current regulations, no activities have occurred after March 1 in previously undisturbed areas during late winter. Therefore, no monitoring with specially-trained dogs has been required. Also during this period, there were 82 reportable small spills (such as 0.25 gallons of hydraulic fluid, 3 gallons of power steering fluid, or other relatively small amounts of sewage, motor oil, hydraulic oil, sulfuric acid, etc.), three of which reached Beaufort water or ice. All material (for example, 0.03 gallons of hydraulic fluid) from these three spills was completely recovered.

NMFS has determined that BP complied with the mitigation and monitoring requirements set forth in regulations and annual LOAs. In addition, NMFS has determined that the impacts on marine mammals and on the availability of marine mammals for subsistence uses from the activity fell within the nature and scope of those anticipated and authorized in the previous authorization (supporting the analysis in the current authorization).

Estimated Take of Marine Mammals

One of the main purposes of NMFS' effects assessments is to identify the permissible methods of taking, which involves an assessment of the following criteria: the nature of the take (e.g., resulting from anthropogenic noise vs. from ice road construction, etc.); the regulatory level of take (i.e., mortality vs. Level A or

Level B harassment); and the amount of take. In the ``Potential Effects of the Specified Activity on Marine Mammals'' section earlier in this document, NMFS identified the different types of effects that could potentially result from activities at BP's Northstar facility.

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

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patterns, including, but not limited to, migration, breathing, nursing, breeding, feeding, or sheltering [Level B harassment].'' Take by Level

B harassment is anticipated from operational sounds extending into the open-water migration paths of cetaceans and open-water areas where pinnipeds might be present, from the physical presence of personnel on the island, vehicle traffic, and by helicopter overflights. Take of hauled out pinnipeds, by harassment, could also occur as a result of in-air sound sources. Certain species may have a behavioral reaction to the sound emitted during the activities; however, hearing impairment as a result of these activities is not anticipated because of the low source levels for much of the equipment that is used. There is also a potential for take by injury or mortality of ringed seals from ice road construction activities. Because of the slow speed of hovercraft and vessels used for Northstar operations, it is highly unlikely that there would be any take from these activities.

Because BP operates the Northstar facility year-round, take of marine mammals could occur at any time of year. However, take of all marine mammal species that could potentially occur in the area is not anticipated during all seasons. This is because of the distribution and habitat preferences of certain species during certain times of the year. This is explained further in this section and BP's application

(see ADDRESSES).

Estimated Takes in the Ice-covered Season

Potential sources of disturbance to marine mammals from the

Northstar project during the ice-covered period consist primarily of vehicle traffic along the ice-road, helicopter traffic, and the ongoing production and drilling operations on the island. During the ice- covered season, the ringed seal is the only marine mammal that occurs regularly in the area of landfast ice surrounding Northstar. Spotted seals do not occur in the Beaufort Sea in the ice-covered season. Small numbers of bearded seals occur occasionally in the landfast ice in some years. Bowhead and beluga whales are absent from the Beaufort Sea in winter (or at least from the landfast ice portions of the Beaufort

Sea), and in spring their eastward migrations are through offshore areas north of the landfast ice, which excludes whales from areas close to Northstar. Gray whales are also absent from this part of the

Beaufort Sea during the ice-covered season. Therefore, takes of marine mammals during the ice-covered season were only estimated for ringed and bearded seals.

Potential displacement of ringed seals was more closely related to physical alteration of sea ice by industry than to exposure to detectable levels of low-frequency industrial sound during winter and spring (Williams et al., 2006; Richardson et al., 2008b; Moulton et al., MS). The distance within which displacement of ringed seals might occur near a development like Northstar was defined as the physically affected area plus a 328 ft (100 m) buffer zone. A study from a drill site in the Canadian Beaufort Sea provided similar results (Harwood et al., 2007). The Northstar ice road is typically flooded and thickened and/or cleared of snow. The physically affected ice road area is about 1,312 ft (400 m) wide, and this is extended with 328 ft (100 m) on either side to a total width of 1,969 ft (600 m) to derive the zone of displacement. This zone of displacement (or impact zone) around physically affected areas such as the ice road, work areas on the ice, and Northstar Island itself, is used to calculate the number of seals potentially affected (Richardson et al., 2008b).

(1) Bearded Seal

The few bearded seals that remain in the area during winter and spring are generally found north of Northstar in association with the pack ice or the edge of the landfast ice. Bearded seals were not observed on the fast ice during the 1997 or 1998 BP/LGL surveys (G.

Miller, LGL Ltd., pers. comm.), but small numbers were noted there in 1999-2002 (Moulton et al., 2003b). No bearded seals were seen during spring aerial surveys from Oliktok Point to Flaxman Island (Frost et al., 1997, 1998). The large size of this phocid makes it conspicuous to observers, reducing the likelihood of missing animals on the ice and hence underestimating abundance. Based on available data, and the ecology of bearded seals, it is unlikely that more than a few bearded seals (and most likely none) will be present in close proximity (0.62 mi (1 km) from Northstar.

Passing boats and helicopters might cause startle reactions and other short-term effects.

Based on the above assumptions, BP estimated that 15 ringed seals might be present and potentially affected during the open-water season

(i.e., 3.1 km\2\ x 0.38 seals/km\2\ x 13 weeks). BP notes that this estimate is subject to wide uncertainty (in either direction) given the uncertainties in each of the three assumptions listed above. There is no specific evidence that any of the seals occurring near Northstar during the 1997-2009 open-water seasons were disturbed appreciably or otherwise affected by BP's activities (Williams et al., 2006a; Moulton et al., 2003a, 2005; Rodrigues et al., 2006; Rodrigues and Richardson, 2007; Aerts and Rodrigues, 2008; Aerts, 2009). BP requests the take of 15 ringed seals per year during the open-water season by Level B harassment.

(4) Bowhead Whale

Bowhead whales are not resident in the region of activity. During the open-water season, relatively few westward migrating bowheads occur within 6.2 mi (10 km) of Northstar during most years. However, in some years (especially years with relatively low ice cover) a larger percentage of the bowhead population migrates within 6.2-9.3 mi (10-15 km) of Northstar (Treacy, 1998; Blackwell et al., 2007, 2009). The bowhead whale population in the Bering-Chukchi-Beaufort area was estimated to include approximately 10,545 animals (CV = 0.128) in 2001.

To estimate the 2011 population size for purposes of calculating potential ``takes'', the annual rate of increase was assumed to be steady at 3.4% (George et al., 2004). Based on these figures, the 2011 population size could be approximately 14,625 bowhead whales.

About 43.7% of the bowheads in the Bering-Chukchi-Beaufort stock are sexually mature (Koski et al., 2004), and about 25% of the mature females are pregnant during autumn migration (Zeh et al., 1993). About 50.5% of the whales in this stock are juveniles (excluding calves), and 5.8% are calves (Koski et al., 2004). The sex ratio is close to 1:1; about half of each category would be males and half females. There are few data on the age and sex composition of bowhead whales that have been sighted near the Prudhoe Bay area. The few data

Page 39739

from the area and more extensive data from more easterly parts of the

Alaskan Beaufort Sea in late summer/autumn (Koski and Johnson, 1987;

Koski and Miller, 2002, 2009) suggest that almost all age and sex categories of bowheads could be encountered, i.e., males, non-pregnant females, pregnant females, and calves (mostly 3-6 months old). Newly born calves (=180 or >=190 dB re 1

micro

Pa (rms) at locations where whales or seals could be exposed. At least one on-island observer shall be stationed at a location providing an unobstructed view of the predicted safety zone. The observer(s) shall scan the safety zone continuously for marine mammals for 30 minutes prior to the operation of the sound source. Observations shall continue during all periods of operation. The observer shall record the: Species and numbers of marine mammals seen within the 180 or 190 dB zones; bearing and distance of the marine mammals from the observation point; and behavior of marine mammals and any indication of disturbance reactions to the monitored activity.

(e) BP shall conduct any additional monitoring measures contained in a Letter of Authorization issued under Sec. Sec. 216.106 and 217.148 of this chapter.

(f) BP shall submit an annual report to NMFS within the time period specified in a Letter of Authorization issued under Sec. Sec. 216.106 and 217.148 of this chapter.

(g) If specific mitigation and monitoring are required for activities on the sea ice initiated after March 1 (requiring searches with dogs for lairs), during the operation of strong sound sources

(requiring visual observations and shutdown procedures), or for the use of new sound sources that have not previously been measured, then a preliminary summary of the activity, method of monitoring, and preliminary results shall be submitted to NMFS within 90 days after the cessation of that activity. The complete description of methods, results, and discussion shall be submitted as part of the annual report.

(h) BP shall submit a draft comprehensive report to NMFS, Office of

Protected Resources, and NMFS, Alaska Regional Office (specific contact information to be provided in Letter of Authorization), no later than 240 days prior to the expiration of these regulations. This comprehensive technical report shall provide full

Page 39747

documentation of methods, results, and interpretation of all monitoring during the first four and a quarter years of the LOA. Before acceptance by NMFS as a final comprehensive report, the draft comprehensive report shall be subject to review and modification by NMFS scientists.

(i) Any observations concerning possible injuries, mortality, or an unusual marine mammal mortality event shall be transmitted to NMFS,

Office of Protected Resources, and the Alaska Stranding and

Disentanglement Program (specific contact information to be provided in

Letter of Authorization), within 48 hours of the discovery. At a minimum, reported information shall include: The time, date, and location (latitude/longitude) of the animal(s); the species identification or description of the animal(s); the fate of the animal(s), if known; and photographs or video footage of the animal (if equipment is available).

Sec. 217.147 Applications for Letters of Authorization.

(a) To incidentally take marine mammals pursuant to these regulations, the U.S. Citizen (as defined by Sec. 216.103) conducting the activity identified in Sec. 217.140(a) (i.e., BP) must apply for and obtain either an initial Letter of Authorization in accordance with

Sec. 217.148 or a renewal under Sec. 217.149.

(b) [Reserved]

Sec. 217.148 Letters of Authorization.

(a) A Letter of Authorization, unless suspended or revoked, shall be valid for a period of time not to exceed the period of validity of this subpart.

(b) The Letter of Authorization shall set forth:

(1) Permissible methods of incidental taking;

(2) Means of effecting the least practicable adverse impact on the species, its habitat, and on the availability of the species for subsistence uses (i.e., mitigation); and

(3) Requirements for mitigation, monitoring and reporting.

(c) Issuance and renewal of the Letter of Authorization shall be based on a determination that the total number of marine mammals taken by the activity as a whole will have no more than a negligible impact on the affected species or stock of marine mammal(s) and will not have an unmitigable adverse impact on the availability of species or stocks of marine mammals for taking for subsistence uses.

Sec. 217.149 Renewal of Letters of Authorization and adaptive management.

(a) A Letter of Authorization issued under Sec. 216.106 and Sec. 217.148 of this chapter for the activity identified in Sec. 217.140(a) shall be renewed upon request by the applicant or determination by NMFS and the applicant that modifications are appropriate pursuant to the adaptive management component of these regulations, provided that:

(1) NMFS is notified that the activity described in the application submitted under Sec. 217.147 will be undertaken and that there will not be a substantial modification to the described work, mitigation or monitoring undertaken during the upcoming 12 months;

(2) NMFS recieves the monitoring reports required under Sec. 217.146(f) and (g); and

(3) NMFS determines that the mitigation, monitoring and reporting measures required under Sec. Sec. 217.144 and 217.146 and the Letter of Authorization issued under Sec. Sec. 216.106 and 217.148 of this chapter were undertaken and will be undertaken during the upcoming annual period of validity of a renewed Letter of Authorization.

(b) If either a request for a renewal of a Letter of Authorization issued under Sec. Sec. 216.106 and 217.149 of this chapter or a determination by NMFS and the applicant that modifications are appropriate pursuant to the adaptive management component of these regulations indicates that a substantial modification, as determined by

NMFS, to the described work, mitigation or monitoring undertaken during the upcoming season will occur, NMFS will provide the public a period of 30 days for review and comment on the request. Review and comment on renewals of Letters of Authorization are restricted to:

(1) New cited information and data indicating that the determinations made in this document are in need of reconsideration, and

(2) Proposed substantive changes to the mitigation and monitoring requirements contained in these regulations or in the current Letter of

Authorization.

(c) A notice of issuance or denial of a renewal of a Letter of

Authorization will be published in the Federal Register.

(d) Adaptive Management--NMFS may modify or augment the existing mitigation or monitoring measures (after consulting with BP regarding the practicability of the modifications) if doing so creates a reasonable likelihood of more effectively accomplishing the goals of mitigation and monitoring set forth in the preamble of these regulations. Below are some of the possible sources of new data that could contribute to the decision to modify the mitigation or monitoring measures:

(1) Results from BP's monitoring from the previous year;

(2) Results from general marine mammal and sound research; or

(3) Any information which reveals that marine mammals may have been taken in a manner, extent or number not authorized by these regulations or subsequent LOAs.

Sec. 217.150 Modifications of Letters of Authorization.

(a) Except as provided in paragraph (b) of this section, no substantive modification (including withdrawal or suspension) to the

Letter of Authorization issued by NMFS, pursuant to Sec. Sec. 216.106 and 217.148 of this chapter and subject to the provisions of this subpart, shall be made until after notification and an opportunity for public comment has been provided. For purposes of this paragraph, a renewal of a Letter of Authorization under Sec. 217.149, without modification (except for the period of validity), is not considered a substantive modification.

(b) If the Assistant Administrator determines that an emergency exists that poses a significant risk to the well-being of the species or stocks of marine mammals specified in Sec. 217.142(c), a Letter of

Authorization issued pursuant to Sec. Sec. 216.106 and 217.148 of this chapter may be substantively modified without prior notification and an opportunity for public comment. Notification will be published in the

Federal Register within 30 days subsequent to the action.

FR Doc. 2011-16327 Filed 7-5-11; 8:45 am

BILLING CODE 3510-22-P

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