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 Department of Commerce National Oceanic and Atmospheric Administration [I.D. 052401B]
 AGENCY: National Marine Fisheries Service (NMFS), National Oceanic and Atmospheric Administration (NOAA), Commerce.
 ACTION: ACTION:  Notice of receipt of application and proposed authorization for a small take exemption; request for comments.
 SUMMARY: NMFS has received a request from WesternGeco, LLC (formerly Western Geophysical) for an authorization to take small numbers of marine mammals by harassment incidental to conducting ocean bottom cable (OBC) seismic surveys in the Alaskan Beaufort Sea.  Under the Marine Mammal Protection Act (MMPA), NMFS is requesting comments on its proposal to authorize WesternGeco 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 2001.
 DATES: Comments and information must be received no later than July 16, 2001.
 ADDRESSES: Comments on the application should be addressed to Donna Wieting, Chief, Marine Mammal Conservation Division, Office of Protected Resources, NMFS, 1315 East-West Highway, Silver Spring, MD  20910-3225.  A copy of the application, the Technical Monitoring Plan, the Environmental Assessment (EA), and a list of references used in this document may be obtained by writing to this address or by telephoning one of the contacts listed here.
 FOR FURTHER INFORMATION CONTACT: Simona Perry Roberts, Office of Protected Resources (301) 713-2322, ext. 106, or Brad Smith, Alaska Region (907) 271-5006.


SUPPLEMENTARY INFORMATION: Background Sections 101 (a)(5)(A) and (D) of the MMPA (16 U.S.C. 1361 
                    *et seq*.) direct the Secretary of Commerce to allow, upon request, the incidental, but not intentional taking of small numbers of marine mammals by U.S. citizens who engage in a specified activity (other than commercial fishing) within a specified geographical region if certain findings are made and either regulations are issued or, if the taking is limited to harassment, notice of a proposed authorization is provided to the public for review. Permission may be granted if NMFS finds that the taking will have no more than a negligible impact on the species or stock(s) and will not have an unmitigable adverse impact on the availability of the species or stock(s) for subsistence uses and that 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 (IHAs) under section 101 (a)(5)(D) of the MMPA for activities in Arctic waters.  For additional information on the procedures to be followed for this authorization, please refer to that document. Summary of Request On April 16, 2001, NMFS received an application from WesternGeco requesting an authorization for the harassment of small numbers of several species of marine mammals incidental to conducting OBC seismic surveys during the open water season in the south central Beaufort Sea off Alaska between western Camden Bay and Harrison Bay.  The primary area of seismic activity is expected to be an area approximately 16 by 7 kilometers (km) (10 miles (mi) by 4 mi) in and near Simpson Lagoon, west of Prudhoe Bay and offshore of Oliktok Point.  Weather permitting, the survey is expected to take place between approximately July 15 and late October, 2001.  WesternGeco anticipates completing six survey patches during the 2001 open water season.  A detailed description of the work proposed for 2001 is contained in the application (WesternGeco, 2001) which is available upon request (see 
                    **ADDRESSES**
                    ). Description of the Activity Seismic surveys are used to obtain data about geological formations several thousands of feet deep.  The proposed seismic operation is an OBC survey.  WesternGeco's OBC survey involves dropping cables from a ship to the ocean bottom, forming a patch consisting of 4 parallel cables 8.9 km (5.5 mi) long, separated by approximately 600 meters (m) (1,968 feet (ft)) from each other.  Hydrophones and geophones, attached to the cables, are used to detect seismic energy reflected back from rock strata below the ocean bottom.  The source of this energy is a submerged acoustic source, called a seismic airgun array, that releases compressed air into the water, creating an acoustical energy pulse that is directed downward toward the seabed.  WesternGeco will use two source vessels for the open-water 2001 seismic surveys, one for deep water and one for shallow water, primarily shoreward of the barrier islands. The deep water vessel, the R/V 
                    *Arctic Star*, will utilize an airgun array with an air discharge volume of 1,210 cubic inches 
                    ( print page 32322)
                    (in3
                    ) (19.8 liters, L).  The maximum source levels for the 
                    *Arctic Star*
                     will be at 249 dB re 1 micro Pascal per minute (Pa-m) (when the acoustic pressure is 29.4 bar-meters (zero to peak)), or 253 dB re 1 micro Pa-m (when the acoustic pressure is 45.9 bar-meters (peak-to-peak)).  Most operations utilizing the 1,210 in3
                     array are expected to operate at a gun depth of 2.3 m (7.5 ft) and water depth of <10 m (<32.8 ft).  The shallow water source vessel, the R/V 
                    *Peregrine*
                    , will utilize an airgun array with an air discharge volume of 640 in3
                     (10.48 L).  The source level maximums for the 
                    *Peregrine*
                     will be at 237 dB re 1 micro Pa-m (when the acoustic pressure is 6.7 bar-meters (zero to peak)), or 242 dB re 1 micro Pa-m (when the acoustic pressure is 12.2 bar-meters (peak to peak)).  These airgun arrays are smaller and less powerful than the arrays used in some other seismic programs in the Beaufort Sea prior to 1999 and are expected to operate at a gun depth of 1 m (3.3 ft) in very shallow water. The seismic vessels will sail along pre-plotted source lines arranged orthogonally to the OBCs.  Each source line will be 5 km (3.1 mi) long and adjacent source lines will be approximately 500 m (1,640 ft) apart.  There will be 34  source lines for each seismic patch.  The overall grid of source lines for a given patch will be 4.7 km by 16.5 km (2.9 mi by 10.2 mi) and the source line for one patch will overlap with those from adjacent patches. After sufficient data have been recorded to allow accurate mapping of the rock strata, the cables are lifted onto the deck of one of the two self-powered cable vessels (R/V 
                    *Western Endeavor*
                     and R/V 
                    *Western Frontier*), moved to a new location (ranging from several hundred to a few thousand feet away), and placed onto the seabed again.  A small utility vessel (
                    *Ski Barge*) may also be used to transfer seismic crew and/or marine mammal observers, as well as supplies and refuse, between the seismic vessels and Prudhoe Bay.  Air support will be limited to infrequent (if any) helicopter flights and, starting in early September, aerial surveys at altitudes from 900 to 1500 ft (274 to 457 m). For a more detailed description of the seismic operation, please refer to WesternGeco (2001). Description of Habitat and Marine Mammals Affected by the Activity A detailed description of the Beaufort Sea ecosystem and its associated marine mammals can be found in several documents (Corps of Engineers, 1999; NMFS, 1999; Minerals Management Service (MMS), 1992, 1996) and is not repeated here. Marine Mammals The Beaufort/Chukchi Seas support a diverse assemblage of marine mammals, including bowhead whales (
                    *Balaena mysticetus*), gray whales (
                    *Eschrichtius robustus*), beluga whales(
                    *Delphinapterus leucas*), ringed seals (
                    *Phoca hispida*), spotted seals (
                    *Phoca largha*) and bearded seals (
                    *Erignathus barbatus*).  Descriptions of the biology and distribution of these species and of others can be found in NMFS (1999), Western Geophysical (2000), WesternGeco (2001), the annual monitoring reports for seismic surveys in the Beaufort Sea (LGL Ltd. and Greeneridge Sciences Inc, 1997, 1998, 1999, 2000) and several other documents (Corps of Engineers, 1999; Lentfer, 1988; MMS, 1992, 1996; Ferrero 
                    *et al.*, 2000).  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.  Support vessels and aircraft may provide a potential secondary source of noise.  The physical presence of vessels and aircraft could also lead to non-acoustic effects on marine mammals involving visual or other cues. Underwater pulsed sounds generated by open water seismic operations may be detectable a substantial distance away from the activity.  The effect of these pulsed sounds on living marine resources, particularly marine mammals in the area, will be dependent on the hearing sensitivity of the species, the behavior of the animal at the time the sound is detected, as well as the distance and level of the sound relative to ambient conditions.  Any sound that is detectable is (at least in theory) capable of eliciting a disturbance or avoidance reaction by some marine mammals or of masking signals of comparable frequency that are generated by marine mammals (e.g., whale calls) (WesternGeco, 2001).  An incidental harassment take is presumed to occur when marine mammals in the vicinity of the seismic source, the seismic vessel, other vessels, or aircraft show a disturbance or avoidance reaction to the generated sounds or to visual cues. When the received levels of noise exceed some behavioral reaction threshold, cetaceans will show disturbance reactions.  The levels, frequencies, and types of noise that will elicit a response vary between and within species, individuals, locations, and seasons.  Behavioral changes may be subtle alterations in the surface, respiration, and dive 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.  Seismic pulses have been observed to cause strong avoidance reactions by many of the bowhead whales occurring within a distance of several kilometers, including changes in surfacing, respiration and dive cycles, and to sometimes cause avoidance or other changes in bowhead behavior at considerably greater distances  (Richardson 
                    *et al.*, 1995; Rexford, 1996; MMS, 1997; Miller 
                    *et al.*, 1999).  Airgun pulses may also disturb some other marine mammal species occurring in the area.  Ringed seals within a few hundred meters of an airgun array showed variable behavior to the noise, with some moving somewhat farther away and other seals not moving far at all (Harris 
                    *et al.*, 1997, 1998, in press; Lawson and Moulton, 1999; Moulton and Lawson, 2000). Although some masking of low-frequency sounds (e.g., bowhead and gray whale calls) is a possibility for this activity, the intermittent nature of seismic survey pulses used by WesternGeco (1 second in duration every 16 to 24 seconds), as well as the fact that airgun operations are expected to occur no more than 50 percent of the time, will limit the extent of any masking.  Bowhead whales are known to continue calling in the presence of seismic survey sounds, and their calls can be heard between seismic pulses (Greene 
                    *et al.*, 1997, 1999; Richardson 
                    *et al.*, 1986).  Masking effects are expected to be absent in the case of beluga whales, given that sounds utilized by them are at much higher frequencies (in the 2 to 6 kilohertz (kHz) range) (Sjare and Smith, 1986) than are airgun sounds from WesternGeco's seismic surveys (highest frequency of 188 hertz(Hz)) (WesternGeco, 2001). Permanent hearing damage is not expected to occur during the project.  There is no direct evidence that the hearing systems of marine mammals close to an airgun array would be at risk of temporary or permanent hearing impairment; however, depending on the species, the equipment being used, and the number of pulses to which the animal is exposed, temporary threshold shift (TTS) is a theoretical possibility for 
                    ( print page 32323)
                    animals within a few hundred meters of the source (Richardson 
                    *et al.*, 1995; Finneran 
                    *et al.*,2000).  Planned monitoring and mitigation measures, proposed by WesternGeco and described later in this document, are designed to avoid sudden onsets of seismic pulses at full power, to detect marine mammals occurring near the array, and to avoid exposing them to sound pulses that have any possibility of causing hearing impairment. Bowhead Whales Studies conducted prior to 1996 (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.  In three studies of bowhead whales and one of gray whales during this period, surfacing-dive cycles were unusually rapid in the presence of seismic noise, with fewer breaths per surfacing and longer intervals between breaths (Richardson 
                    *et al.*, 1986; Koski and Johnson, 1987; Ljungblad 
                    *et al.*, 1988; Malme 
                    *et al.*, 1988).  This pattern of subtle effects was evident among bowhead whales 6 km to at least 73 km (3.7 to 45.3 mi) from seismic vessels.  One visibly apparent avoidance response reported from pre-1996 studies involved observations of bowhead whales swimming away from a seismic vessel 24 km (15 mi) away (Koski and Johnson, 1987).  It is likely that some migrating bowhead whales show avoidance at distances exceeding those at which Ljungblad 
                    *et al.*
                    (1988) and Richardson 
                    *et al.*
                     (1986) observed responses.  However, at distances greater than around 24 km (15 mi), only subtle changes in the surfacing, respiration, dive cycles were detectable (Richardson 
                    *et al.*, 1986). Results from the 1996-1998 BP, Inc. and Western Geophysical seismic monitoring program indicate that most migrating bowhead whales deflected seaward to avoid an area within about 20 km (12.4 mi) of an active nearshore seismic operation when there were no barrier islands or very shallow water between the seismic operation and the whales (Miller 
                    *et al.*, 1998, 1999).  The available data do not provide an unequivocal estimate of the distance at which approaching bowhead whales began to deflect, but this may be on the order of 35 km (21.7 mi).  It is also uncertain how far beyond (west of) the seismic operation the seaward deflection persisted (Miller 
                    *et al.*, 1999).  Although very few bowhead whales approached within 20 km (12.4 mi) of the operating seismic vessel, the number of bowhead whales sighted within that area returned to normal within 12-24 hours after the airgun operations ended (Miller 
                    *et al.*, 1999). Inupiat whalers believe that migrating bowhead whales are sometimes displaced at distances considerably greater than suggested by the pre-1996 scientific studies (Rexford, 1996).  Also, whalers believe that avoidance effects can extend out to distances on the order of 30 miles, and that bowhead whales exposed to seismic pulses are also skittish and difficult to approach.  The “skittish” behavior may be related to the observed subtle changes in the behavior of bowhead whales exposed to seismic pulses from distant seismic vessels (Richardson 
                    *et al.*, 1986). Gray Whales The reactions of gray whales to seismic pulses are similar to those documented for bowhead whales during the 1980s.  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 approximately 50 percent of the migrating gray whales showed avoidance when the average received pulse level was 170 dB (re 1 micro-Pa).  By some behavioral measures, clear effects were evident at average pulse levels of 160+ dB, and less consistent results were suspected at levels of 140-160 dB, farther away.  Recent research on migrating gray whales showed responses similar to those observed in the earlier research when the source was moored in the migration corridor 2 km (1.2 mi) from shore.  However, when the source was placed offshore (4 km (2.5 mi)) of the migration corridor, the avoidance response was not evident on track plots (Tyack and Clark, 1998). Beluga Whale The beluga whale is the only species of toothed whale (Odontoceti) expected to be encountered in the Beaufort Sea.  Beluga whales have poor hearing thresholds at frequencies below 200 Hz, where most of the energy from airgun arrays is concentrated.  Their thresholds at these frequencies (as measured in a captive situation), are 125 dB re 1 micro-Pa or more depending upon frequency (Johnson 
                    *et al.*, 1989).  Although not expected to be significantly affected by the noise, given the high source levels of seismic pulses, airgun sounds may sometimes be audible to beluga whales at distances of 100 km (62.1 mi)(Richardson and Wursig, 1997), and perhaps further if actual low-frequency hearing thresholds in the open sea are better than those measured in captivity (WesternGeco, 2001).  The reaction distance for beluga whales, although presently unknown, is expected to be less than that for bowhead whales, given the presumed poorer sensitivity of beluga whales to low-frequency sounds (WesternGeco, 2001). Ringed, Spotted, 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 (LGL and Greeneridge, 1997, 1998, 1999a; J. Parsons as quoted in Greene, 
                    *et al.*
                     1985; Anon., 1975; Mate and Harvey, 1985).  Also, the results from the 1996-2000 BP and Western Geophysical monitoring studies provide a substantial amount of directly relevant information (Harris et al., 1997, 1998, in press; Lawson and Moulton, 1999; Moulton and Lawson, 2000).  During these monitoring studies, the operation of the airgun array had minor and variable effects on the behavior of seals within a few hundred meters of the array and (to a limited extent) the distribution of seals around the source vessel (Moulton and Lawson, 2000).  Nonetheless, seals were observed throughout each season in the general area where seismic operations were occurring.  Seals were sometimes observed within the 190 dB re 1 micro-Pa designated safety radii, and at these times the airguns were shut down. Underwater audiograms have been obtained for three species of phocinid seals - the ringed, harbor, and harp seals (
                    *Pagophilus groenlandicus*).  These audiograms were reviewed in Richardson et al. (1995) and 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 micro-Pa.  There are few published data on hearing sensitivity of phocid 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 micro-Pa at 100 Hz (Kastak and Schusterman, 1998). Based on published references (see LGL and Greeneridge, 1997, 1998, 1999a; Thompson 
                    *et al.*
                     1998), it is unlikely that pinnipeds would be harassed or injured by low frequency sounds from a seismic source unless 
                    ( print page 32324)
                    they were within relatively close proximity of the seismic array.  For permanent injury, pinnipeds would likely need to remain in the high-noise field for extended periods of time.  Existing evidence also suggests that, while seals may be capable of hearing sounds from seismic arrays, they 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/Washington Department of Wildlife, 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 Beaufort Sea waters, pinnipeds have been previously exposed to seismic noise and may not react to it after initial exposure. For a discussion on the anticipated effects of ships, boats, and aircraft on marine mammals and their food sources, please refer to the application (WesternGeco, 2001). Information on these effects is preliminarily adopted by NMFS as the best information available on this subject. Numbers of Marine Mammals Expected to Be Taken WesternGeco estimates that the following numbers of marine mammals may be subject to Level B harassment, as defined in 50 CFR 216.3: *Species*
*Population Size*
*Takes  by  Harassment  in  2001**Maximum  Number1*
*Probable2*Bowhead whale
8,200160  dB  criterion
-
1,000
<50020  km  criterion
-
2,630
1,300Gray whale
26,000
<10
0Beluga whale
39,258
250
<150Ringed  seal3
1-1.5  million
400
<200Spotted  seal3
>
                            200,000
10
<2Bearded  seal3
>
                            300,000
50
<151
                         The  maximum  number  that  might  be  taken  if  seismic  surveys  are  operable  during  the  September/October  period  and  the  bowhead  migration  passes  unusually  close  to  shore  as  in  1997.2
                         The  number  that  could  be  taken  under  the  most  likely  operating  conditions.3
                         Some  individual  seals  may  be  harassed  more  than  once.
 Estimates  of  Marine  Mammal  Takes Estimates  of  takes  by  harassment  will  be  made  through  vessel  and/or  aerial  surveys.   Preliminarily,  WesternGeco  will  estimate  the  number  of  (1)  marine  mammals  observed  within  the  area  strongly  ensonified  by  the  OBC  seismic  vessel  (see  Mitigation  section  below  for  area  description);  (2)  marine  mammals  observed  showing  apparent  avoidance  or  disturbance  reactions  to  seismic  pulses  (e.g.,  heading  away  from  the  seismic  vessel  in  an  atypical  direction);  (3)  marine  mammals  estimated  to  be  subject  to  take  by  type  (1)  or  (2)  when  no  monitoring  observations  were  possible;  and  (4)  bowhead  whales  whose  migration  routes  came  within  20  km  or  greater  (actual  distance  dependent  on  a  combination  of  1996-1998  and  2001  data)  of  the  operating  OBC  seismic  vessel,  or  would  have  if  they  had  not  been  displaced  farther  offshore. Effects  of  Seismic  Noise  and  Other  Activities  on  Subsistence  Needs The  disturbance  and  potential  displacement  of  marine  mammals  by  sounds  from  seismic  activities  are  the  principle  concerns  related  to  subsistence  use  of  the  area.   The  harvest  of  marine  mammals  (mainly  bowhead  whales,  but  also  ringed  and  bearded  seals)  is  central  to  the  culture  and  subsistence  economies  of  the  coastal  North  Slope  communities.   In  particular,  if  migrating  bowhead  whales  are  displaced  farther  offshore  by  elevated  noise  levels,  the  harvest  of  these  whales  could  be  more  difficult  and  dangerous  for  hunters.   The  harvest  could  also  be  affected  if  bowhead  whales  become  more  “skittish”  when  exposed  to  seismic  noise. Nuiqsut  is  the  community  closest  to  the  area  of  the  proposed  activity.   The  communities  of  Barrow  and  Kaktovik  also  harvest  resources  that  pass  through  the  general  area,  but  do  not  regularly  hunt  in  the  planned  seismic  exploration  area.   Subsistence  hunters  from  all  three  communities  conduct  an  annual  hunt  for  migrating  bowhead  whales  during  the  autumn  months.   In  recent  years,  Nuiqsut  whalers  typically  take  two  to  four  whales  each  year  (WesternGeco,  2001).   Nuiqsut  whalers  concentrate  their  efforts  on  areas  north  and  east  of  Cross  Island,  generally  in  water  depths  greater  than  20  m  (65  ft). Whalers  from  the  village  of  Kaktovik  search  for  whales  east,  north,  and  west  of  the  village.   Kaktovik  is  located  72  km  (45  mi)  east  of  the  easternmost  end  of  WesternGeco’s  planned  2001  seismic  exploration  area. Whalers  from  the  village  of  Barrow  search  for  bowhead  whales  much  farther  from  the  planned  seismic  area, 
                    >
                     200  km  (
                    >
                    125  mi)  to  the  west  (WesternGeco,  2001). The  location  of  the  proposed  seismic  activity  is  south  of  the  center  of  the  westward  migration  route  of  bowhead  whales,  but  there  is  some  limited  overlap  with  the  southern  limit  of  the  migration.   Seismic  monitoring  results  from  1996-1998  indicate  that  most  bowhead  whales  avoid  the  area  within  about  20  km  (12.4  mi)  around  the  airgun  array  when  it  is  operating,  and  some  avoid  the  area  within  30  km  (18.6  mi).   In  addition,  bowhead  whales  may  be  able  to  hear  the  sounds  emitted  by  the  seismic  array  out  to  a  distance  of  50  km  (31.1  mi)  or  more,  depending  on  the  ambient  noise  level  and  the  efficiency  of  sound  propagation  along  the  path  between  the  seismic  vessel  and  the  whale  (Miller 
                    *et  al.*,  1997). Cross  Island,  the  principle  field  camp  location  for  Nuiqsut  whalers,  is  located  within  the  general  area  of  the  proposed  2001  seismic  area.   Thus,  the  possibility  and  timing  of  potential  seismic  operations  in  the  Cross  Island  area  requires  WesternGeco  to  provide  NMFS  with  either  (1)  a  Plan  of  Cooperation  with  the  Alaska  Eskimo  Whaling  Commission  (AEWC)  and  the  North  Slope  whaling  communities,  or  (2)  measures  that  have  been  or  will  be  taken  to  avoid  any  unmitigable  adverse  impact  on  the  availability  of  these  animals  for  subsistence  needs.   WesternGeco’s  application  has  preliminarily  identified  those  measures  that  will  be  taken  to  minimize  any  adverse  effect  on  subsistence.   In  addition,  the  timing  of  seismic  operations  will  be  addressed  in  a  Conflict  Avoidance  Agreement  (CAA) 
                    ( print page 32325)
                     with  the  Nuiqsut  whalers  and  the  AEWC  (WesternGeco,  2001).   Also,  the  monitoring  plan  proposed  by  WesternGeco  (2001)  is  expected  to  provide  information  that  will  help  resolve  uncertainties  about  the  effects  of  seismic  exploration  on  the  accessibility  of  bowhead  whales  to  hunters. Nuiqsut  hunters  also  hunt  seals  for  subsistence  purposes.   Most  seal  hunting  has  been  during  the  early  summer  in  open  water.   Boat  crews  hunt  ringed,  spotted,  and  bearded  seals.   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.    The  planned  seismic  exploration  during  the  summer  has  some  potential  to  influence  seal  hunting  activities  by  residents  of  Nuiqsut.   During  BP  and  Western  Geophysical's  1996-2000  seismic  programs,  an  operating  airgun  array  apparently  did  not  displace  seals  by  more  than  a  few  hundred  meters  (and  usually  much  less).  Therefore,  because  WesternGeco  is  proposing  similar  mitigation  and  consultation  procedures  this  year,  it  is  unlikely  that  seismic  activities  would  have  more  than  a  negligible  impact  on  Nuiqsut  seal  hunting. Anticipated  Impact  on  Habitat The  proposed  seismic  activity  is  not  expected  to  cause  significant  and  permanent  impacts  on  habitats  used  by  marine  mammals,  or  to  the  food  sources  they  utilize.   The  main  impact  associated  with  the  proposed  activity  will  be  temporarily  elevated  noise  levels. Prey  fish  often  react  to  sounds,  especially  strong  and/or  intermittent  sounds  of  low  frequency  (Chapman  and  Hawkins,  1969;  Pearson 
                    *et  al.*,  1992;  Skalski 
                    *et  al.*,  1992).   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  disturbing  activity  may  again  elicit  disturbance  responses  from  the  same  fish.   Fish  near  the  airgun  arrays  are  likely  to  dive  to  the  bottom  or  exhibit  some  other  kind  of  behavioral  response  (WesternGeco,  2001).   This  would  likely  have  little  or  no  impact  on  seal  or  beluga  whale  feeding  in  the  shallow  areas  where  seismic  work  is  planned. Many  crustaceans  can  make  sounds  and  some  Crustacea  and  other  invertebrates  have  some  type  of  sound  receptor.   However,  the  reactions  of  zooplankton  and  benthic  animals,  the  primary  prey  species  of  bowhead  and  gray  whales,  to  sound  are  not  known.   Zooplankton  may  react  to  the  shock  wave  from  an  airgun  array  when  they  occur  very  close  to  the  source.   However,  little  or  no  mortality  is  expected.   A  reaction  by  zooplankton  to  a  seismic  impulse  would  only  be  relevant  to  bowhead  whales  if  it  caused  a  concentration  of  zooplankton  to  scatter.   Pressure  changes  of  sufficient  magnitude  to  cause  this  type  of  reaction  would  probably  occur  only  very  close  to  the  source.   Impacts  on  zooplankton  behavior  are  predicted  to  be  negligible  and  this  would  translate  into  negligible  impacts  on  feeding  bowhead  whales. Physical  contact  with  the  ocean  bottom  by  cables  and  ancillary  equipment  will  be  temporary  and  in  a  very  small  fraction  of  the  potential  survey  area.   The  use  of  OBCs  could  result  in  some  short-term  disturbance  to  sediments  and  benthic  organisms  in  the  immediate  area  of  the  cable.   Recovery  of  disturbed  soft-bottom  areas  will  occur  in  a  manner  similar  to  that  occurring  after  natural  disturbances  by  ice  scour. The  2001  OBC  survey  area  may  overlap  with  areas  identified  as  “Boulder  Patch”  habitat.   If  such  overlap  occurs,  WesternGeco  will  adhere  to  any  applicable  requirements  identified  by  the  responsible  governmental  agencies. Mitigation For  the  2001  seismic  operations,  WesternGeco  will  reduce  its  primary  airgun  array  from  the  1,500  in3
                     used  in  1998  to  1,210  in3
                    .   This  reduction  in  volume  will  lower  the  source  levels  and  result  in  lower  received  levels  at  each  distance  compared  to  Western  Geophysical's  1998  project.   The  smaller  volume  640  in3
                     airgun  array  consists  of  sixteen  40  in3
                     airguns  in  four  4-gun  clusters.   The  airguns  comprising  this  small  volume  array  will  be  spread  out  horizontally,  such  that  the  energy  from  the  array,  like  that  from  the  1,210  in3
                     array,  will  be  directed  downward  as  far  as  possible.  The  distances  within  which  received  levels  (see  the  proposed  safety  radii  below)  can  exceed  190  dB  and  180  dB  re  1  micro-Pa  have  been  measured  at  two  airgun  depths  (2.3  and  5  m  or  7.5  and  16.4  ft)  and  in  two  water  depths  (8  and  23  m  or  26.2  and  75.5  ft)  (Greene  and  McLennan,  2000),  and  are  reduced  relative  to  those  around  the  1998  array.   The  shallower  depth  at  which  the  640  in3
                     array  will  operate  will  tend  to  reduce  the  source  level  (and  hence  the  190  and  180  dB  safety  radii)  even  farther;  however,  as  a  precautionary  approach,  the  190  and  180  dB  radii  for  the  1,210  in3
                     airgun  operating  at  2.3  m  (7.5  ft)  depth  will  be  assumed  to  apply  to  the  640  in3
                     array  operating  at  1  m  (3.3  ft)  gun  depth. Proposed  safety  radii  for  OBC  seismic  operations  in  2001  are  based  on  comprehensive  measurements  of  the  sounds  recorded  in  the  water  near  the  OBC  array  in  1999  and  analyzed  by  Greene  and  McLennan  (2000). Vessel-based  observers  will  monitor  marine  mammal  presence  in  the  vicinity  of  the  seismic  arrays  throughout  the  seismic  program.   To  avoid  the  potential  for  injury,  WesternGeco  proposes  to  immediately  shut  down  the  seismic  source  if  seals  and/or  whales  are  sighted  within  the  proposed  safety  radii.   The  proposed  safety  radii  are  as  follows: SOURCE (in3
                            )
AIRGUN  DEPTH (m/ft)
WATER  DEPTH (m/ft)
SAFETY  RADII(m/ft)190 dB (Seals)
180 dB (Whales)1210
2.3/7.5
<
                            10/
                            <
                            32.8
100
1501210
2.3/7.5
>
                            10/
                            >
                            32.8
160
5501210
5/16.4
<10/<32.8
160
3501210
5/16.4
>
                            10/
                            >
                            32.8
260
900640
1/3.3
<
                            10/
                            <
                            32.8
100
150640
1/3.3
>
                            10/
                            >
                            32.8
160
550
 In  addition,  WesternGeco  proposes  to  ramp-up  the  1,210  in3
                     and  640  in3
                     seismic  sources  to  operating  levels  at  a  rate  no  greater  than  6  dB  per  minute.   Under  normal  operational  conditions  (source  vessel  speed  at  least  4  knots),  a  ramp-up  would  be  required  after  the  array  has  been  inactive  for  a  period  lasting  1  minute  or  longer.   If  the  towing  speed  is  reduced  to  3  knots  or  less,  it  is  proposed  that  a  ramp-up  would  be  required  after  the  array  has  been  inactive  for  a  period  lasting  2  minutes  or  longer.   Ramp-up  will  begin  with  an  air  volume  discharge  not  exceeding  80 
                    ( print page 32326)
                     in3
                     for  the  1,210  in3
                    ,  and  40  in3
                     for  the  640  in3
                     array.   Additional  guns  will  be  added  at  appropriate  intervals  so  as  to  limit  the  rate  of  increase  in  source  level  to  6  dB  per  minute. Monitoring As  part  of  its  application,  WesternGeco  provided  a  monitoring  plan  for  assessing  impacts  to  marine  mammals  from  seismic  surveys  in  the  Beaufort  Sea.   This  monitoring  plan  is  described  in  WesternGeco  (2001)  and  in  LGL,  Ltd.  and  Greeneridge  Sciences  Inc.  (2001).   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. WesternGeco  plans  to  conduct  the  following  monitoring: Vessel-based  Visual  Monitoring It  is  proposed  that  one  or  two  marine  mammal  observers  aboard  the  seismic  source  vessel  will  search  for  and  observe  marine  mammals  whenever  seismic  operations  are  in  progress  and  for  at  least  30  minutes  before  the  planned  start  of  seismic  transmissions.   These  observers  will  scan  the  area  immediately  around  the  vessels  with  reticle  binoculars  during  the  daytime.   Laser  rangefinding  binoculars  will  be  available  to  assist  with  distance  estimation.   If  operations  continue  after  mid-August,  when  the  duration  of  darkness  increases,  image  intensifiers  and  additional  light  sources  will  be  used  to  illuminate  the  safety  zone  (see  application  for  more  detail). A  total  of  four  observers  (three  trained  biologists  and  one  Inupiat  observer/communicator)  will  be  based  aboard  the  seismic  source  vessel 
                    *Arctic  Star*.   They  will  work  in  teams  of  two,  with  individual  watches  limited  to  no  more  than  4  consecutive  hours. A  total  of  two  observers  will  be  based  aboard  the  seismic  source  vessel 
                    *Peregrine*.   Individual  watches  will  be  limited  to  no  more  than  4  consecutive  hours.   In  addition,  wheelhouse  staff  aboard  the 
                    *Peregrine*
                     will  assist  in  maintaining  a  watch  for  marine  mammals.   If  operations  continue  for  substantially  more  than  12  hours  per  day,  1  or  2  additional  observers  will  be  required  on  a  rotating  basis. When  marine  mammals  are  detected  within  or  about  to  enter  the  safety  zone  designated  to  prevent  injury  to  the  animals  (see  Mitigation),  the  geophysical  crew  leader  will  be  notified  and  the  airgun(s)  will  be  shut  down  immediately. Aerial  Surveys If  OBC  seismic  work  continues  after  August  31,  2001,  aerial  surveys  by  WesternGeco's  marine  mammal  contractor,  LGL  Ltd.,  would  occur  from  the  date  on  which  OBC  seismic  operations  commence  until  1  day  after  the  OBC  seismic  operations  end.   If  OBC  seismic  work  is  suspended  during  the  bowhead  subsistence  hunting  season,  but  resumes  later  in  the  autumn,  aerial  surveys  will  commence  (or  resume)  when  OBC  seismic  work  resumes.   WesternGeco  proposes  to  continue  aerial  surveys  until  1  day  after  OBC  seismic  work  ends. The  primary  objective  of  the  aerial  surveys  will  be  to  document  the  occurrence,  distribution,  and  movements  of  bowhead  whales,  and  (secondarily)  beluga  and  gray  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  to  assess  the  possibility  that  seismic  operations  affect  the  accessibility  of  bowhead  whales  for  subsistence  hunting.   Pinnipeds  will  be  recorded  when  seen,  although  survey  altitude  will  be  too  high  for  systematic  surveys  of  seals.   Sonobuoys  will  be  dropped  to  document  seismic  and  ambient  noise  at  offshore  locations,  including  locations  near  whales. WesternGeco  proposes  to  fly  at  300  m  (1,000  ft)  in  areas  where  no  whaling  is  underway,  but  it  may  reduce  that  altitude  to  no  less  than  275  m  (900  ft)  under  low  cloud  conditions.   In  addition,  and  subject  to  the  terms  of  the  2001  CAA  with  subsistence  communities,  surveys  may  be  flown  at  457  m  (1500  ft)  altitude  over  areas  where  whaling  is  occurring  on  that  date  and  should  avoid  direct  overflights  of  whaleboats  and  Cross  Island,  where  whalers  from  Nuiqsut  are  based  during  their  autumn  whale  hunt. The  daily  aerial  surveys  are  proposed  to  cover  a  grid  of  18  north-south  lines  spaced  8  km  (5  mi)  apart  and  extending  seaward  to  about  the  100  m  (328  ft)  depth  contour  (typically  about  65  km  (40.4  mi)  offshore).   This  grid  will  extend  from  about  65  km  (40.3  mi)  east  to  65  km  (40.3  mi)  west  of  the  area  in  which  seismic  operations  are  underway  on  that  date.   This  survey  design  will  provide  extended  coverage  to  determine  the  eastward  and  westward  extent  of  the  offshore  displacement  of  whales  by  seismic  operations.   In  2001,  no  “intensive”  grid  surveys  are  planned  to  be  conducted  because  very  few  whales  occur  within  20  km  (12.4  mi)  of  the  seismic  operation. Detailed  information  on  the  aerial  survey  program  can  be  found  in  WesternGeco(2001)  and  in  LGL  Ltd.  and  Greeneridge  Sciences  Inc.  (2001),  which  are  incorporated  in  this  document  by  citation. Acoustical  Measurements The  acoustic  measurement  program  proposed  for  2001  is  designed  to  provide,  in  conjunction  with  existing  results  from  previous  years  (see   LGL  and  Greeneridge  Sciences  Inc.,  1997,  1998,  1999),  the  specific  acoustic  data  needed  to  document  the  seismic  sounds  to  which  marine  mammals  will  be  exposed  in  2001.    Proposed  emphasis  is  on  situations  and  locations  not  studied  in  detail  during  previous  operations. WesternGeco  has  two  basic  objectives  for  collecting  acoustic  measurements,  one  physical  and  one  biological.   The  physical  acoustics  objective  is  to  determine  the  characteristics  of  airgun  array  pulses  as  received  in  the  bowhead  migration  corridor  at  varying  distances  offshore  and  to  the  east  of  the  area  of  seismic  exploration  in  2001  and  in  1996-98  plus  2001  combined.  Pulse  characteristics  to  be  determined  are  received  levels  and  pulse  durations  versus  range  offshore  and  to  the  east,  spectral  properties,  and  signal-to-ambient  ratios.   These  measurements  will  only  be  made  if  seismic  operations  continue  into  September/October.   The  biological  objective  is  to  determine  whether  there  are  differences  in  the  pattern  of  bowhead  call  detection  rates  near,  offshore  of,  and  east  of  the  seismic  exploration  area  at  times  with  and  without  active  seismic  operations  based  on  2001  data  and  combined  1996-98  and  2001  data.   If  there  are  differences,  then  WesternGeco  proposes  to  use  the  combined  acoustic  and  aerial  survey  data  to  evaluate  whether  the  noise-related  differences  in  call  detection  rate  are  attributable  to  differences  in  calling  behavior,  whale  distribution,  or  a  combination  of  the  two. In  2001,  the  acoustic  measurement  program  is  planned  to  include  (1)  deployment  in  late  August/September  of  autonomous  seafloor  acoustic  recorders  (ASARs)  to  provide  continuous  acoustic  data  for  extended  periods,  and  (2)  use  of  air-dropped  sonobuoys  in  September/October.   WesternGeco  proposes  to  use  these  methods  only  if  OBC  surveys  occur  in  September/October. (1)  The  ASARs  would  be  placed  on  the  sea  bottom  at  three  locations  in  late  August  or  September  if  OBC  seismic  work  extends  into  the  September/October  2001  period.   This  method  provides  a  large  number  of  measurements  of  received  characteristics  of  seismic  pulses  in  the  whale  migration  corridor  well  offshore  and  east  of  the  area  of  OBC  seismic  exploration.   ASARs  would  also  provide  continuous  data  on  whale  calling 
                    ( print page 32327)
                     patterns  at  times  with  and  times  without  airgun  operations.  These  recorders  would  also  collect  data  on  ambient  noise  levels. (2)  Sonobuoys  would  be  dropped  and  monitored  from  survey  aircraft  during  September/October  (if  the  seismic  operations  are  continuing  at  that  time)  at  an  average  rate  of  about  two  sonobuoys  per  day  of  aerial  surveys  on  days  when  bowhead  whales  are  seen.   This  method  provides  data  on  received  levels  and  other  characteristics  of  seismic  pulses  received  in  the  bowhead  whale  migration  corridor,  including  some  of  the  specific  locations  where  bowhead  whales  are  observed.   Sonobuoys  would  also  provide  the  ambient  noise  data  needed  to  estimate  signal-to-noise  ratios  for  seismic  pulses  received  by  whales. For  a  more  detailed  description  of  planned  monitoring  activities,  please  refer  to  the  application  and  the  Technical  Monitoring  Plan  (WesternGeco,  2001;  LGL  Ltd.  and  Greeneridge  Sciences  Inc.,  2001). Reporting WesternGeco  will  provide  an  initial  report  on  2001  activities  to  NMFS  within  90  days  after  the  end  of  the  seismic  program.   This  report  will  summarize  dates  and  locations  of  seismic  operations,  marine  mammal  sightings  (dates,  times,  locations,  behaviors,  associated  seismic  survey  activities),  estimates  of  the  amount  and  nature  of  all  takes  by  harassment  or  in  other  ways,  and  any  apparent  effects  on  accessibility  of  marine  mammals  to  subsistence  users. A  final  technical  report  will  be  provided  by  WesternGeco  no  later  than  April  30,  2002.   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  (ESA),  NMFS  completed  an  informal  consultation  on  the  issuance  of  an  IHA  for  similar  activities  on  July  26,  1999.   If  an  authorization  to  incidentally  harass  listed  marine  mammals  is  issued  under  the  MMPA  for  this  activity,  NMFS  will  issue  an  Incidental  Take  Statement  under  section  7  of  the  ESA. National  Environmental  Policy  Act  (NEPA) In  1999,  NMFS  conducted  an  environmental  assessment  (EA)  on  the  impacts  of  conducting  seismic  surveys  during  the  open  water  season  in  the  U.S.  Beaufort  Sea.   In  that  analysis  NMFS  determined  that  neither  the  authorization  for  the  harassment  of  small  numbers  of  several  species  of  marine  mammals  incidental  to  conducting  seismic  surveys  nor  the  alternatives  to  that  action  would  significantly  affect  the  quality  of  the  human  environment.   Since  this  proposed  action  by  WesternGeco,  LLC  does  not  differ  from  actions  previously  analyzed  by  NMFS  under  the  1999  EA,  this  action  is  categorically  excluded  from  further  NEPA  review  (NOAA  NAO  216-6).   A  copy  of  the  1999  EA  is  available  upon  request  (see 
                    **ADDRESSES**
                    ). Preliminary  Conclusions NMFS  has  preliminarily  determined  that  the  short-term  impact  of  conducting  seismic  surveys  in  the  Alaskan  Beaufort  Sea  will  result,  at  worst,  in  a  temporary  modification  in  behavior  by  certain  species  of  cetaceans  and  possibly  by  pinnipeds.   While  behavioral  modifications  may  be  made  by  these  species  to  avoid  the  resultant  noise,  this  behavioral  change  is  expected  to  have  a  negligible  impact  on  the  animals. While  the  number  of  potential  incidental  harassment  takes  will  depend  on  the  annual  variability  in  distribution  and  abundance  of  marine  mammals  within  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  minimized  through  the  incorporation  of  the  mitigation  measures  mentioned  in  this  document.   No  rookeries,  mating  grounds,  year-round  areas  of  concentrated  feeding,  or  other  areas  of  special  significance  for  marine  mammals  occur  within  or  near  the  planned  area  of  operations  during  the  season  of  operations. 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  August  31,  2001,  until  1  day  after  the  OBC  seismic  operations  end,  aerial  survey  flights  for  bowhead  whale  assessments  are  proposed  to  be  undertaken  by  WesternGeco.   If  OBC  seismic  work  is  suspended  during  the  bowhead  subsistence  hunting  season,  but  resumes  later  in  the  autumn,  aerial  surveys  will  commence  (or  resume)  when  OBC  seismic  work  resumes.   The  proposed  duration  for  aerial  surveys  will  be  a  reduction  from  previous  years.   WesternGeco  believes  this  reduction  is  appropriate  because  some  of  the  main  questions  about  disturbance  to  bowhead  whales  from  a  nearshore  seismic  operation  were  answered  by  the  1996-1998  monitoring  projects.   In  addition,  the  MMS  expects  to  conduct  its  broad-scale  aerial  survey  work  from  approximately  August  31  until  the  end  of  the  bowhead  migration  in  October.   WesternGeco  believes  that  this  combined  aerial  survey  data  will  provide  sufficient  information  to  estimate  the  numbers  of  bowhead  whales  taken  by  harassment. 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  WesternGeco  and  subsistence  users. Open-water  seismic  exploration  in  the  Alaskan  Beaufort  Sea  does  have  some  potential  to  influence  seal  hunting  activities  by  residents  of  Nuiqsut.   However,  because  the  main  summer  sealing  by  the  village  of  Nuiqsut  is  conducted  off  the  Colville  Delta,  west  of  the  proposed  survey  area,  and  the  zone  of  influence  by  seismic  sources  on  seals  is  expected  to  be  fairly  small  (less  than  a  few  hundred  meters),  NMFS  believes  that  WesternGeco’s  OBC  seismic  survey  will  not  have  an  unmitigable  adverse  impact  on  the  availability  of  seals  for  subsistence  uses. Proposed  Authorization Provided  the  previously  mentioned  mitigation,  monitoring,  and  reporting  requirements  are  incorporated,  NMFS  proposes  to  issue  an  IHA  to  WesternGeco  for  an  OBC  seismic  survey  during  the  2001  Alaskan  Beaufort  Sea  open  water  season.   NMFS  has  preliminarily  determined  that  the  proposed  seismic  activity  would  result  in  the  harassment  of  only  small  numbers  of  bowhead  whales,  beluga  whales,  ringed  seals,  bearded  seals,  and  possibly  spotted  seals  and  gray  whales;  would  have  no  more  than  a  negligible  impact  on  these  marine  mammal  stocks;  and  would  not  have  an  unmitigable  adverse  impact  on  the  availability  of  marine  mammal  stocks  for  subsistence  uses. Information  Solicited NMFS  requests  interested  persons  to  submit  comments,  and  information,  concerning  this  request  (see 
                    **ADDRESSES**
                    ). Dated:  June 7,  2001. Wanda L. Cain, Acting Deputy Director, Office of Protected Resources.


[FR Doc. 01-15060 Filed 6-13-01; 8:45 am] BILLING CODE  3510-22-S