# Small Takes of Marine Mammals Incidental to Specified Activities; Offshore Seismic Activities in the Beaufort Sea > Briefs, arguments, decisions, and more. URL: https://www.frixlaw.com/law-library/documents/fr%3A96-13287 ## Record - **Collection:** Federal Register - **Document type:** Notice - **Published:** May 28, 1996 - **Citation:** 61 FR 26501 ## Text DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration [I.D. 050196A] Small Takes of Marine Mammals Incidental to Specified Activities; Offshore Seismic Activities in the Beaufort Sea AGENCY: National Marine Fisheries Service (NMFS), National Oceanic and Atmospheric Administration (NOAA), Commerce. ACTION: Notice of receipt of application and proposed authorization for a small take exemption; request for comments. ----------------------------------------------------------------------- SUMMARY: NMFS has received a request from the BP Exploration (Alaska) 900 East Benson Boulevard, Anchorage, AK 99519 (BPX) for authorization to take small numbers of marine mammals by harassment incidental to conducting seismic surveys in the Northstar Unit, in the Beaufort Sea in state and federal waters. Under the Marine Mammal Protection Act (MMPA), NMFS is requesting comments on its proposal to authorize BPX to incidentally take, by harassment, small numbers of bowhead whales and other marine mammals in the above mentioned area during the open water period of 1996. DATES: Comments and information must be received no later than June 27, 1996. ADDRESSES: Comments on the application should be addressed to Chief, Marine Mammal Division, Office of Protected Resources, National Marine Fisheries Service, 1315 East-West Highway, Silver Spring, MD 20910- 3225. A copy of the application, an environmental assessment (EA), and a list of references used in this document may be obtained by writing to this address, by telephoning one of the contacts listed below or by leaving a voice mail request at (301) 713-4070. FOR FURTHER INFORMATION CONTACT: Kenneth R. Hollingshead, Office of Protected Resources, NMFS, (301) 713-2055, Ron Morris, Western Alaska Field Office, NMFS, (907) 271-5006. SUPPLEMENTARY INFORMATION: Background Section 101(a)(5)(A) and (D) of the MMPA (16 U.S.C. 1361 et seq.) directs the Secretary of Commerce 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) within a specified geographical region if certain findings are made and either regulations are issued or, if the taking is limited to harassment, notice of a proposed authorization is provided to the public for review. Permission may 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 the permissible methods of taking and requirements pertaining to the monitoring and reporting of such taking are set forth. On April 10, 1996 (61 FR 15884), NMFS published an interim rule establishing, among other things, procedures for issuing incidental harassment authorizations under section 101(a)(5)(D) of the MMPA in Arctic waters. For additional information on the procedures to be followed for this authorization, please refer to that document. Summary of Request On March 18, 1996, NMFS received an application from BPX requesting an authorization for the harassment of small numbers of several species of marine mammals incidental to conducting seismic surveys during the open water season within the Northstar Unit, located in the Beaufort Sea in U.S. waters. The survey is expected to take place between approximately July 20 and October 20, 1996. A detailed description of the work planned is contained in the application (BPX 1996) and is available upon request (see ADDRESSES). Description of Habitat and Marine Mammal Affected by the Activity A detailed description of the Beaufort Sea ecosystem and its associated marine mammals can be found in the EA prepared for this authorization (SAIC 1996) or in other documents (Minerals Management Service (MMS) 1992, 1996) and need not be repeated here. A copy of the EA is available upon request (see ADDRESSES). Marine Mammals The Beaufort/Chukchi Seas support a diverse assemblage of marine mammals including bowhead whales (Balaena glacialis), gray whales (Eschrichtius robustus), belukha (Delphinapterus leucas), ringed seals (Phoca hispida), spotted seals (Phoca largha) and bearded seals (Erignathus barbatus). Descriptions on the biology and distribution of these species, and others, can be found in several other documents (BPX 1996, Lentfer 1988, MMS 1992, NMFS 1990 and 1996, Small and DeMaster 1995). Please refer to those documents for information on these species. Potential Effects of Seismic Surveys on Marine Mammals. Disturbance by seismic noise is the principal means of taking by this activity. Vessel and aircraft will provide a secondary source of noise. Deep seismic surveys are used to obtain data about formations several thousands of feet deep. The physical presence of vessels could also lead to non-acoustic effects involving visual or other cues. These surveys are accomplished by transmitting sound waves into the earth, which are reflected [[Page 26502]] off subsurface formations and recorded with detectors in the water column. A typical marine seismic source is an airgun array, which releases compressed air into the water creating an acoustical energy pulse that is directed downwards toward the seabed. Hydrophones spaced along a streamer cable just below the surface of the water receive the reflected energy from the subsurface formations and transmit data to the seismic vessel. Onboard the vessel, the signals are amplified, digitized, and recorded on magnetic tape. Depending upon ambient conditions and the sensitivity of the receptor, underwater sounds produced by open water seismic operations may be detectable some substantial distance away from the activity. Any sound that is detectable is (at least in theory) capable of eliciting a disturbance reaction by a marine mammal or masking a signal of comparable frequency (BPX 1996). An incidental harassment take is presumed to occur when marine mammals in the vicinity of the seismic source (or other vessels) react to the generated sounds or visual cues. Seismic pulses are known to cause bowhead whales to behaviorally respond within a distance of several kilometers (Richardson et al. 1995). Although some limited masking of low-frequency sounds (e.g., whale calls) is a possibility, the intermittent nature of seismic source pulses will limit the extent of masking. Bowhead whales are known to continue calling in the presence of seismic survey sounds, and their calls can be heard between seismic pulses (Richardson et al. 1986). Hearing damage is not expected to occur during the project. It is not known whether a marine mammal very close to an air gun array would be at risk of temporary or permanent hearing impairment, but temporary threshold shift is a theoretical possibility for animals within a few hundred meters (Richardson et al. 1995). Planned monitoring and mitigation measures (described below) are designed to detect marine mammals occurring near the array and to avoid exposing them to sound pulses that have any possibility of causing hearing damage. When the received levels of noise exceed some behavioral reaction threshold, cetaceans will show disturbance reactions (BPX 1996). The levels, frequencies, and types of noise that will elicit a response vary between and within species, individuals, locations and season. Behavioral changes may be subtle alterations in surface-dive- respiration cycles. More conspicuous responses, include changes in activity or aerial displays, movement away from the sound source, or complete avoidance of the area. The reaction threshold and degree of response are related to the activity of the animal at the time of the disturbance. Whales engaged in active behaviors such as feeding, socializing or mating are less likely than resting animals to show overt behavioral reactions, unless the disturbance is directly threatening (BPX 1996). Bowhead Whales Various studies (Reeves et al. 1984, Fraker et al. 1985, Richardson et al. 1986, Ljungblad et al. 1988) have reported that, when an operating seismic vessel approaches within a few kilometers, most bowhead whales exhibit strong avoidance behavior and changes in surfacing, respiration, and dive cycles. Bowheads exposed to seismic pulses from vessels more than 4.5 miles (7.5 km) away rarely showed observable avoidance of the vessel, but their surface, respiration, and dive cycles appeared altered in a manner similar to that observed in whales exposed at a closer distance (BPX 1996). Within a 3.7-60 mile (6-99 km) range, it has not been possible to determine a specific distance at which subtle behavioral changes no longer occur (Richardson and Malme 1993), given the high variability observed in bowhead whale behavior (BPX 1996). Gray Whales The reactions of gray whales to seismic pulses is similar to those of bowheads. Migrating gray whales along the California coast were noted to slow their speed of swimming, turn away from seismic noise sources, and increase their respiration rates. Malme et al. (1983, 1984, 1988) concluded that about 50 percent showed avoidance when the average received pulse level was 170 dB (re 1 Pa @ 1 m). Less consistent results were indicated at levels of 140-160 dB. Belukha The belukha is the only species of toothed whale (Odontoceti) expected to be encountered in the Beaufort Sea. Because its hearing threshold at frequencies below 100 Hz (where most of the energy from air gun arrays is concentrated) is poor (125 dB re 1 Pa @ 1 m) or more depending upon frequency (Johnson et al. 1989 (as referenced in BPX 1996), Richardson 1991, 1995), belukha are not predicted to be strongly influenced by seismic noise. However, because of the high source levels of seismic pulses, airgun sounds may be audible to belukha at large distances (Richardson 1991, 1995). Ringed, Largha and Bearded Seals No detailed studies of reactions by seals to noise from open water seismic exploration have been published (Richardson et al. 1995). However, there are some data on the reactions of seals to various types of impulsive sounds (J. Parsons as quoted in Greene et al. 1985, Anon. 1975, Mate and Harvey 1985). These studies indicate that ice seals typically either tolerate or habituate to seismic noise produced from open water sources. Underwater audiograms have been obtained using behavioral methods for 3 species of phocinid seals, ringed, harbor, and harp seals (Pagophilus groenlandicus). These audiograms were reviewed in Richardson et al. (1995). 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 Pa @ 1 m). There are few data on hearing sensitivity of phocinid seals below 1 kHz. NMFS considers harbor seals to have a hearing threshold of 70-85 dB at 1 kHz (60 FR 53753, October 17, 1995), and recent measurements for a harbor seal indicate that, below 1 kHz, its thresholds deteriorate gradually to 97 dB (re 1 Pa @ 1 m) at 100 Hz (Kastak and Schusterman, 1995a,b). Because no studies to date have focused on pinniped reaction to underwater noise from pulsed, seismic arrays in open water (Richardson et al., 1991, 1995), as opposed to in-air exposure to continuous noise, substantive conclusions are not possible at this time. However, assuming an sound pressure level needed to be 80-100 dB over its threshold in order to cause annoyance and 130 dB for injury (pain), as is the current thought based upon human studies (ARPA, 1995), then it appears unlikely that pinnipeds would be harassed or injured by low frequency sounds from a seismic source unless they were within close proximity of the array. For permanent injury, marine mammals would need to remain in the high noise field for extended periods of time. Existing evidence also suggests that, while they may be capable of hearing sounds from seismic arrays, seals appear to tolerate intense pulsatile sounds, without known effect, once they learn that there is no danger associated with the noise (see, for example, NMFS/WDFW, 1995). In addition, they will apparently not abandon feeding or breeding areas due to exposure to these noise sources (Richardson et al. 1991) and may habituate to certain noises over time. Since seismic work is fairly common in Western Beaufort Sea waters, pinnipeds have previously been [[Page 26503]] exposed to seismic noise, and may not react to it, after initial exposure. Effects of Seismic Noise and other Activities on Subsistence Needs. The disturbance and potential displacement of marine mammals by sounds from seismic activities is the principle concern related to subsistence use of the area. The harvest of marine mammals (mainly bowhead whales, ringed seals, and bearded seals) is central to the culture and subsistence economies of the coastal North Slope communities (BPX 1996). Displacement of migrating marine mammals farther offshore due to behavioral changes resulting from elevated noise levels could potentially make harvest of these species more difficult. Nuiqsut is the community closest to the area of the proposed activity, and only harvests bowhead whales during the fall whaling season. Nuiqsut whalers typically take zero to three whales each season, with a trend toward larger harvests in the most recent years (BPX 1996). Nuiqsut whalers concentrate their efforts on areas north and east of the Northstar Unit, generally in water depths greater than 65 ft (20 m). Cross Island, located 13 miles (20 km) east of the eastern edge of the primary area of proposed activity, is the principle field camp location for Nuiqsut whalers. Thus, most bowhead whales will not enter the ensonified area until they have passed through the area used by Nuiqsut whalers (BPX 1996). The location of the proposed seismic activity is to the south of the main westward migration route of bowhead whales. BPX believes that although whales may be able to hear the sounds emitted by the seismic array out to a distance of 30 miles (50 km) or more, it is unlikely that changes in migration route will occur at distances of >15 miles (>25 km). As discussed above, scientific studies have shown obvious avoidance reactions at distances up to 3.7-5 miles (6-8 km), with one probable case of avoidance at 15 miles (24 km)(Richardson et al. 1986, Koski and Johnson 1987, Ljungblad et al. 1988). However, other bowheads >3.7 miles (>6 km) from shallow-water seismic operations showed no obvious avoidance (BPX 1996). It is difficult to determine the maximum distance at which reactions occur (Moore and Clark 1992), although whalers believe that some migrating bowheads are deflected by seismic operations at distances greater than those documented by scientific studies done to date. As a result, BPX is developing a Communications and Avoidance Agreement with the whalers (see BPX 1996) to reduce any potential interference with the hunt. Also, it is believed that the monitoring plan proposed by BPX (LGL 1996) will provide information that will help resolve uncertainties about the effects of seismic exploration on the accessibility of bowheads to hunters. In addition, while seismic exploration in the Northstar Unit has some potential to influence subsistence seal hunting activities, the peak season for seal hunting is during the winter months when the harvest consists almost exclusively of ringed seals (BPX 1996). In summer, boat crews hunt ringed, spotted and bearded seals (BPX 1996). The most important sealing area for Nuiqsut hunters is off the Colville delta, extending as far west as Fish Creek and as far east as Pingok Island (BPX 1996). In this area, during summer, sealing occurs by boat when hunters apparently concentrate on bearded seals (BPX 1996). Mitigation BPX proposes to use biological observers to monitor marine mammal presence in the vicinity of the seismic array. To avoid the potential for serious injury to marine mammals, BPX will power down the seismic source if pinnipeds are sighted within 500 ft (150 m) of the source or if cetaceans are sighted within 2,130 ft (650 m) of the source. At 500 ft (150 m), the average pulse levels will be less than 190 dB (re 1 Pa @ 1 m). At 2,130 ft (650 m), the average pulse level is expected to be about 180 dB (re 1 Pa @ 1 m), based on the expected characteristics of the air gun array to be used in this program, and on site-specific propagation loss data (from Miles et al. 1987). In addition, NMFS proposes to require BPX to ramp-up the seismic source from a level less than, or equal to, 160 dB to its operating level immediately preceding transmissions at a rate not exceeding 6 dB/ min and to power-down the array to a level no greater than 160 dB whenever marine mammals enter their respective safety zone. NMFS will recommend ramp-up be accomplished through software designed to fire a specified sequence of guns operating at a designated pressure until the full array of guns are firing at peak operating pressure. Monitoring As part of their application, BPX provided a preliminary monitoring plan for assessing impacts to marine mammals from seismic surveys in the Beaufort Sea (LGL 1996). As required by the MMPA, this monitoring plan will be subject to a peer-review panel of technical experts prior to formal acceptance by NMFS. Preliminarily, BPX plans to conduct the following: (1) Vessel-based Visual Monitoring Two biologist-observers aboard the seismic vessel will search for and observe marine mammals whenever seismic operations are in progress, and immediately preceding the start of shooting. These observers will scan the area immediately around the vessels with binoculars during the daytime and with night vision equipment during the night. When mammals are detected within a safety zone designated to prevent injury to the animals, the geophysical crew leader will be notified so that shutdown procedures can be implemented. (2) Aerial Surveys From September 1, 1996 until the seismic program ends, aerial surveys will be conducted daily, weather permitting. The primary objective will be to document the occurrence, distribution, and movements of bowhead and belukha whales in and near the area where they might be affected by the seismic pulses. These observations will be used to estimate the level of harassment takes and for assessing the possibility that seismic operations affect the accessibility of bowhead whales for subsistence hunting. Pinnipeds will be recorded when seen, and sonobuoys will be dropped to document ambient noise and characteristics of seismic noise near whale sightings. Aerial surveys will be at an altitude of 1,000 ft (300 m) above sea level. It is tentatively proposed to avoid direct overflights of the Cross Island area where whalers from Nuiqsut are based during their fall whale hunt. The daily aerial surveys are proposed to cover two grids: (a) A grid of 12 north-south lines spaced 8 km (5 miles) apart and extending to about 30 mi (50 km) offshore, 30 mi (50 km) east, and 12.5 mi (20 km) west of the Northstar area; (b) A grid of 8 north-south lines within the above region, also spaced 5 mi (8 km) apart and mid-way between the longer lines, to provide more intensive coverage of the area of the seismic operations and immediate surrounding waters. (3) Acoustical Measurements A boat-based acoustical measurement program is proposed for a 10- day period in mid- to late-August 1996. The objectives of this survey will be as follows: [[Page 26504]] (a) To measure the levels and other characteristics of the horizontally-propagating seismic survey sounds as a function of distance and aspect relative to BPX's seismic source vessel. (b) To measure acoustic transmission loss vs. frequency, distance, and propagation direction in and near the Northstar Unit, based on transmission and reception of standardized acoustic signals having a source level of about 165 dB re 1 Pa @ 1 m. Transmissions will not be done if bowheads are seen within 2,130 ft (650 m) of the seismic array. (c) To obtain additional site-specific ambient noise data, which determine signal-to-noise ratios for seismic and other acoustic signals at various ranges from their sources. In addition, data on ambient noise and on characteristics of seismic pulses will be obtained from sonobuoys dropped and monitored from the survey aircraft after September 1, 1996. For a more detailed description of planned monitoring activities, please refer to the application and supporting document (LGL 1996). Reporting BPX will provide an initial report to NMFS within 90 days of the completion of the seismic program. This report will provide dates and locations of seismic operations, details of marine mammal sightings, estimates of the amount and nature of all takes by harassment, and any apparent effects on accessibility of marine mammals to subsistence users. A final technical report will be provided by BPX within 20 working days of receipt of the document from the contractor, but no later than April 30, 1996. The final technical report will contain a description of the methods, results, and interpretation of all monitoring tasks. Consultation Under section 7 of the Endangered Species Act, NMFS has begun consultation on the proposed issuance of this authorization. Consultation will be concluded upon completion of the comment period and consideration of those comments in the final determination on issuance of an authorization. National Environmental Policy Act In conjunction with this notice, NMFS has released an EA that addresses the impacts on the human environment from issuance of the authorization and the alternatives to the proposed action. A copy of the EA is available upon request (see ADDRESSES). Conclusions NMFS has preliminarily determined that the short-term impact of conducting seismic surveys in the Northstar Unit of the Beaufort Sea will result, at worst, in a temporary modification in behavior by certain species of cetaceans. While behavioral modifications may be made by these species of cetaceans to avoid the resultant noise, this behavioral change is expected to have a negligible impact on the animals. As the number of potential incidental harassment takes will depend on the distribution and abundance of marine mammals (which vary annually due to variable ice conditions and other factors) in the area of seismic operations, due to the distribution and abundance of marine mammals during the projected period of activity and the location of the proposed seismic activity in waters generally too shallow and distant from the edge of the pack ice for most marine mammals of concern, the number of potential harassment takings is estimated to be small. In addition, no take by injury and/or death is anticipated and the potential for temporary or permanent hearing impairment will be avoided through incorporation of the mitigation measures mentioned above. Because bowhead whales are east of the seismic area in the Canadian Beaufort Sea until late August/early September, seismic activities are not expected to impact subsistence hunting of bowhead whales prior to that date. After September 1, 1996, BPX will initiate aerial survey flights for bowhead whale assessments. Appropriate mitigation measures to avoid an unmitigable adverse impact on the availability of bowhead whales for subsistence needs will be the subject of consultation between BPX and subsistence users. Also, while summer seismic exploration in the Northstar Unit has some potential to influence seal hunting activities by residents of Nuiqsut, because (1) the peak sealing season is during the winter months, (2) the main summer sealing is off the Colville delta (west and inshore of Northstar), and (3) the zone of influence by seismic sources on belukha and seals is fairly small, NMFS believes the Northstar seismic survey will not have an unmitigable adverse impact on the availability of these stocks for subsistence uses. Proposed Authorization NMFS proposes to issue an incidental harassment authorization for the 1996 Beaufort Sea open water season for a seismic survey within the Northstar Unit provided the above mentioned mitigation, monitoring and reporting requirements are incorporated. NMFS has preliminarily determined that the proposed seismic activity would result in the harassment of only small numbers of bowhead whales, gray whales, and possibly belukha whales, bearded seals, and largha seals; will have a negligible impact on these marine mammal stocks; and will not have an unmitigable adverse impact on the availability of these stocks for subsistence uses. Information Solicited NMFS requests interested persons to submit comments, information, and suggestions concerning this request (see ADDRESSES). Dated: May 17, 1996. Patricia A. Montanio, Acting Director, Office of Protected Resources, National Marine Fisheries Service. [FR Doc. 96-13287 Filed 5-23-96; 10:02 am] BILLING CODE 3510-22-F --- Source: Frix Law Library, https://www.frixlaw.com/law-library/documents/fr%3A96-13287. Public record. Not legal advice.