Marine mammals: Incidental taking; authorization letters, etc.— Lamont-Doherty Earth Observatory; Aleutian Islands; marine seismic surveys; cetaceans and pinnipeds,

[Federal Register: August 4, 2005 (Volume 70, Number 149)]

[Notices]

[Page 44901-44913]

From the Federal Register Online via GPO Access [wais.access.gpo.gov]

[DOCID:fr04au05-33]

DEPARTMENT OF COMMERCE

National Oceanic and Atmospheric Administration

[I.D. 020405A]

Small Takes of Marine Mammals Incidental to Specified Activities; Marine Seismic Survey off the Aleutian Islands in the North Pacific Ocean

AGENCY: National Marine Fisheries Service (NMFS), National Oceanic and Atmospheric Administration (NOAA), Commerce.

ACTION: Notice of issuance of an incidental harassment authorization.

SUMMARY: In accordance with provisions of the Marine Mammal Protection Act (MMPA) as amended, notification is hereby given that an Incidental Harassment Authorization (IHA) to take small numbers of marine mammals, by harassment, incidental to conducting oceanographic seismic surveys in the Aleutian Island area has been issued to Lamont-Doherty Earth Observatory (L-DEO).

DATES: Effective from July 18, 2005 through July 17, 2006.

ADDRESSES: The application and authorization are available by writing to Steve Leathery, Chief, Permits, Conservation and Education Division, Office of Protected Resources, National Marine Fisheries Service, 1315 East-West Highway, Silver Spring, MD 20910-3225, by telephoning the contact listed here and are also available at: http://www.nmfs.noaa.gov/prot_res/PR2/Small_ Take/smalltake--

info.htm#applications. Documents cited in this notice can be viewed by appointment during regular business hours at the address provided here.

FOR FURTHER INFORMATION CONTACT: Kenneth Hollingshead, Office of Protected Resources, NMFS, (301) 713-2289, ext 128.

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 marine mammals by U.S. citizens who engage in a specified activity (other than commercial fishing) within a specified geographical region if certain findings are made and either regulations are issued or, if the taking is limited to harassment, a notice of a proposed authorization is provided to the public for review.

An authorization 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 that the permissible methods of taking and requirements pertaining to the monitoring and reporting of such takings are set forth. NMFS has defined ``negligible impact'' in 50 CFR 216.103 as ''...an impact resulting from the specified activity that cannot be reasonably expected to, and is not reasonably likely to, adversely affect the species or stock through effects on annual rates of recruitment or survival.''

Section 101(a)(5)(D) of the MMPA established an expedited process by which citizens of the United States can apply for an authorization to incidentally take small numbers of marine mammals by harassment. Except with respect to certain activities not pertinent here, the MMPA defines ``harassment'' as:

any act of pursuit, torment, or annoyance which (i) has the potential to injure a marine mammal or marine mammal stock in the wild [Level A harassment]; or (ii) has the potential to disturb a marine mammal or marine mammal stock in the wild by causing disruption of behavioral patterns, including, but not limited to, migration, breathing, nursing, breeding, feeding, or sheltering

[Level B harassment] .

Section 101(a)(5)(D) establishes a 45-day time limit for NMFS review of an application followed by a 30-day public notice and comment period on any proposed authorizations for the incidental harassment of marine mammals. Within 45 days of the close of the comment period, NMFS must either issue or deny issuance of the authorization.

Summary of Request

On December 23, 2004, NMFS received an application from L-DEO for the taking, by harassment, of several species of marine mammals incidental to conducting a low-energy, shallow-penetrating seismic survey and scientific rock dredging program around the Aleutian Islands. The purpose of the proposed study is to examine the east-to- west change in the angle of the convergence of the Pacific-North America plates, which implies systematic westward decreases in the rate of subduction and sediment delivery to the Aleutian trench. The Aleutian Island Arc is the only island arc where systematic changes in physical aspects of the subduction system have been well correlated with magma output rates and with the geochemistry of the melts that the system produces. Despite its potential importance, studies of volcanism in the Aleutians are lacking. In particular, the western Aleutians (west of Adak Island) are now playing a key role in the evolving view of subduction magma genesis, yet it remains a poorly studied area. Few volcanic rock samples are available from that area, and it has not been studied substantially at sea.

In addition to an emphasis on magma genesis and its relationship to tectonics, volcanism in the Aleutians and southern Alaska is important because it is known to present a hazard to air traffic. However, the seismic and geochemical studies proposed by L-DEO are not directly hazard-related. They are aimed at understanding the deep-level processes that underlie the volcanic eruptions, and are thus relevant to the broad goals of understanding volcano behavior and hazard assessment in the Aleutians and elsewhere.

Description of the Activity

The seismic survey will involve one vessel, the R/V Thomas G. Thompson (Thompson). The Thompson replaces the R/V Kilo Moana that was originally proposed for use during this survey. The Thompson will deploy one Generator-injector (GI) airgun as an energy source (discharge volume of 105 in3), plus a towed hydrophone streamer up to 300 m (984 ft) long, or possibly as short as

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50 m (164 ft). The Thompson has a length of 83.5 m (274 ft), and a beam of 16 m (52.5 ft). As the GI gun is towed along the survey lines, the receiving system will receive the returning acoustic signals. The proposed program will consist of approximately 4112 km (2220 nm) of seismic survey, and scientific rock dredging at 10 locations. The seismic survey will take place in water depths from less than 50 m (164 ft) to 3.5 kilometers (km) (1.9 nautical miles (nm)). More than 99 percent of the survey will be in depths greater than 100 m (328 ft), and scientific rock dredging will be conducted in water depths 100-1800 m (328-5906 ft), mostly in depths greater than 400 m (1312 ft).

The proposed program will use conventional seismic methodology with a single towed GI-airgun as the energy source, and a towed hydrophone streamer as the receiver system. The energy to the airguns is compressed air supplied by compressors on board the source vessel.

In addition to the GI gun, additional acoustic systems will be operated during much or all of the research cruise. The ocean floor will be mapped with a 30-kHz multi-beam sonar (Simrad EM300) and a dual-frequency (3.5 and 12 kHz) hydrographic echo sounder (Knudson 320B/R). These two systems are commonly operated simultaneously with an airgun array. Other acoustical systems are a 75-kHz acoustic Doppler current profiler (ADCP)(RDI Ocean Surveyor), a Hydrosweep multi-beam sonar will be used as a backup to the Simrad, an 80-kHz navigational echosounder (Abyss Technologies Model IES-10) and a 200-kHz doppler sonar (Ocean Data Equipment Corporation DSN-450 Mark II). Multi-beam bathymetric and single channel surveys will be conducted prior to scientific rock dredging to ensure that dredging is done as accurately and productively as possible. The surveys will also affect the number of dredges that can be completed. While on station for rock dredging, a 12-kHz pinger will be used to monitor the depth of the dredge relative to the sea floor. A detailed description of the acoustic sources proposed for use during this survey can be found in the L-DEO application, which is available at: http://www.nmfs.noaa.gov/prot_res/PR2/Small_Take/smalltake_info.htm#applications .

GI-Airgun Description

The L-DEO portable high-resolution seismic system will be installed on the research vessel for this cruise. The seismic vessel will tow the single GI-airgun and a streamer containing hydrophones along predetermined lines. Seismic pulses will be emitted at intervals of 5- 10 sec. The 5-10 sec spacing corresponds to a shot interval of about 13-26 m (43-85 ft).

The GI airgun will have a total discharge volume of up to 105 in\3\. The gun will be towed 44.3 m (145.3 ft) behind the stern at a depth of about 3 m (9.8 ft). The GI-airgun has a zero to peak (peak) source output of 231 dB re 1 microPascal-m ( 3.6 bar-m) and a peak-to- peak (pk-pk) level of 237 dB (7.0 bar-m). The dominant frequency components of the airgun are in the range of 0-188 Hz. For a one-gun source, the nominal source level represents the actual level that would be found about 1 m (3.3 ft) from the GI gun. Actual levels experienced by any marine organism more than 1 m (3.3 ft) from the GI gun will be significantly lower.

The rms (root mean square) received levels that are used as impact criteria for marine mammals are not directly comparable to the pk or pk-pk values normally used to characterize source levels of airguns. The measurement units used to describe airgun sources, pk or pk-pk decibels, are always higher than the ``root mean square'' (rms) decibels referred to in much of the biological literature. The rms pressure is an average over the pulse duration. For example, a measured received level of 160 dB rms in the far field would typically correspond to a pk measurement of about 170 to 172 dB, and to a pk-pk measurement of about 176 to 178 decibels, as measured for the same pulse received at the same location (Greene, 1997; McCauley et al., 1998, 2000a). The precise difference between rms and pk or p-pk values depends on the frequency content and duration of the pulse, among other factors. However, the rms level is always lower than the pk or pk-pk level for an airgun-type source.

The depth at which the source is towed has a major impact on the maximum near-field output, because the energy output is constrained by ambient pressure. The normal tow depth of the source to be used in this project is 3 m (9.8 ft), where the ambient pressure is 3 decibars. This also limits output, as the 3 decibars of confining pressure cannot fully constrain the source output, with the result that there is loss of energy at the sea surface.

Received sound levels have been modeled by L-DEO for the single GI- airgun in relation to distance and direction from the gun. This publically available model does not allow for bottom interactions, and is most directly applicable to deep water. Based on the model, the distances from the single GI-airgun where sound levels of 190-, 180-, and 160-dB re 1 microPa (rms) are predicted to be received are shown in the greater than 1000-m (328 ft) line of Table 1.

Table 1. Estimated distances to which sound levels 190, 180, and 160 dB re 1 microPa (rms) might be received from the one 105 in3 GI gun that will be used during the seismic survey around the Aleutian Islands during 2005. The safety radii used during the survey will depend on water depth (see text).

Estimated Distances at Received Levels (m) Water depth

-------------------------- 190 dB 180 dB 160 dB

>1000 m

10 27 275 100-1000 m

15 41 413 1000 m; 3281 ft), the L-DEO model tends to overestimate the received sound levels at a given distance (Tolstoy et al., 2004a,b). However, to be precautionary pending acquisition of additional empirical data, L-DEO has proposed using safety radii during GI-airgun operations in deep water that correspond to the values predicted by L-DEO's model for deep water (Table 1). The assumed 190- and 180-dB radii for one GI-airgun are 10 m (33 ft) and 27 m (88 ft), respectively.

Empirical measurements were not conducted for intermediate water

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depths (100-1000 m (328-3281 ft)). On the expectation that results will be intermediate between those from shallow and deep water, L-DEO has applied a 1.5X correction factor to the estimates provided by the model for deep water situations. This is the same factor that was applied to the model estimates during L-DEO cruises in 2003. The assumed 190 and 180 dB radii in intermediate-depth water are 15 m (49 ft) and 41 m (134 ft), respectively (Table 1). L-DEO has requested NMFS use these values for calculating safety ranges in intermediate-depth waters.

Empirical measurements were not made for a single small source operating in shallow water (800 m), operating at 11.25 and 12.6 kHz, and a Simrad EM1002 for shallow water (10-800 m), operating at a frequency of 92 to 98 kHz. This leads to the following assessment:

1. The Kilo Moana's deep water unit, which would have been used during the majority of the survey (approximately 66 percent), emits sound pulses centered at 12 kHz. Baleen whales that would have heard the 12-kHz sonar pulses from the Kilo Moana are unlikely to hear the 30-kHz pulses from the Thompson.

2. The difference in the operating frequencies will be insignificant to odontocetes and pinnipeds, which hear well at both frequencies.

3. The Kilo Moana would have used a 98-kHz multi-beam in shallow waters, approximately 34 percent of the survey, whereas the Thompson will use its 30-kHz system in shallow as well as deep water. Pinnipeds are less sensitive to the higher frequencies, but mysticetes would not hear either the 98-kHz or 30-kHz sounds. For odontocetes, both frequencies are likely to be audible.

4. The pulse lengths of the multi-beam sonars are not substantially different between the systems on the two vessels in either shallow or deep water. The Thompson's multi-beam has a pulse duration of 2 ms in shallow water and up to 15 ms in deep water; the Kilo Moana's multi- beam has a pulse length of 0.2, 0.7, or 2 ms in shallow water and up to 20 ms in deep water.

Overall, effects on marine mammals from the multi-beam sonars on either vessel would be similar. For both vessels, the fore-aft beam width is narrow, so a marine mammal below the surface near the trackline is not likely to be exposed to strong sounds from more than 1 (or a very few) pulses. The short durations of the pulses from either vessel mean that the energy received from one or a few pulses is low. Any effects induced by the multi-beam emissions are expected to be negligible with regard to masking and hearing impairment. Brief exposure to a few signals from any of the proposed multi-beam sonar systems might cause momentary, insignificant behavioral reactions in cetaceans and pinnipeds.

The Thompson's hydrographic echosounder emits pulses at 3.5 and 12 kHz whereas the Kilo Moana's sounder operates at 12, 38, and 200 kHz. The Kilo Moana's sounder would have been operated at the lower frequencies. The impact to marine mammals from the use of the Thompson's hydrographic echo sounder would be the same as, or perhaps less than, that from the Kilo Moana's hydrographic echo sounder.

An ADCP will be used during the survey. The Thompson's ADCP operates at a frequency of 75 kHz, and the Kilo Moana's ADCP operates at 38 kHz. Neither system would be audible to baleen whales. Both systems will be audible to various species of odontocetes.

Estimates of Take by Harassment for the Aleutian Islands Seismic Survey

Given the mitigation measures implemented by L-DEO (see Mitigation later in this document), all anticipated takes involve a temporary change in behavior that may constitute Level B harassment. The required mitigation measures will minimize or eliminate the possibility of Level A harassment or mortality. L-DEO has calculated the ``best estimates'' for the numbers of animals that could be taken by Level B harassment during the proposed Aleutian Islands seismic survey using data on marine mammal density and abundance from marine mammal surveys in the region by Brueggeman et al. (1987, 1988), Troy and Johnson (1989), Dahlheim et al. (2000), Waite et al. (2002), Doroff et al. (2003), Wade et al. (2003), and Tynan (2004), and estimates of the size of the affected area, as shown in the predicted RMS radii table (see Table 1).

These estimates are based on a consideration of the number of marine mammals that might be exposed to sound levels greater than 160 dB, the criterion for the onset of Level B harassment, by operations with the single GI-airgun planned to be used for this project. No animals are expected to exhibit responses to the sonars or pinger given their characteristics (e.g., narrow, downward-directed beam). Therefore, no additional incidental takings are included for animals that might be affected by the multi-beam sonars or 12-kHz pinger.

Table 2 incorporates the corrected density estimates and provides the best estimate of the numbers of each species that would be exposed to seismic sounds greater than 160 dB. A detailed description on the methodology used by L-DEO to arrive at the estimates of Level B harassment takes that are provided in Table 2 can be found in L-DEO's IHA application for the Aleutian Islands survey. BILLING CODE 3510-22-S

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Conclusions

Effects on Cetaceans

Strong avoidance reactions by several species of mysticetes to seismic vessels have been observed at ranges up to 6-8 km (3.2-4.3 nm) and occasionally as far as 20-30 km (10.8-16.2 nm) from the source vessel. However, reactions at the longer distances appear to be atypical of most species and situations, particularly when feeding whales are involved (Miller et al. in press). Fewer than 150 mysticetes are expected to be encountered during the proposed survey in the Aleutian Islands (Table 2) and disturbance effects would be confined to shorter distances given the low-energy acoustic source to be used during this project. In addition, the estimated numbers presented in Table 2 are considered overestimates of actual numbers that may be harassed. Odontocete reactions to seismic pulses, or at least the reactions of dolphins, are expected to extend to lesser distances than are those of mysticetes. Odontocete low-frequency hearing is less sensitive than that of mysticetes, and dolphins are often seen from seismic vessels. In fact, there are documented instances of delphinids and Dall's porpoise approaching active seismic vessels. However, dolphins as well as some other types of odontocetes sometimes show avoidance responses and/or other changes in behavior when near operating seismic vessels.

Taking into account the small size and the relatively low sound output of the single GI-airgun to be used, and the mitigation measures that are planned, effects on cetaceans are generally expected to be limited to avoidance of a small area around the seismic operation and short-term changes in behavior, falling within the MMPA definition of Level B harassment. Furthermore, the estimated numbers of animals potentially exposed to sound levels sufficient to cause appreciable disturbance are very low percentages of the affected populations.

Based on the 160-dB criterion, the best estimates of the numbers of individual odontocete cetaceans that may be exposed to sounds

[gteqt] 160 dB re 1 microPa (rms) represent 0 to approximately 0.4 percent of the regional species populations, except for approximately 3.1 percent for killer whales (Table 2).

Mitigation measures such as controlled speed, course alteration, observers, and shut downs when marine mammals are seen within defined ranges should further reduce short-term reactions, and minimize any effects on hearing. In all cases, the effects are expected to be short- term, with no lasting biological consequence. In light of the type of take expected and the small percentages of affected stocks of cetaceans, the action is expected to have no more than a negligible impact on the affected species or stocks of cetaceans.

Effects on Pinnipeds

Two pinniped species (the Steller sea lion and the harbor seal) are likely to be encountered in the study area. Also, it is possible that a small number of northern fur seals may be encountered, and possible (but very unlikely) that a few ribbon seals may be encountered. An estimated 56 individual harbor seals and 34 individual Steller sea lions (30 m (98 ft). For this action, L- DEO will monitor a safety/shutdown radius of 750 m (2461 ft) around the airgun for Steller sea lions whenever the seismic survey is taking place within designated critical habitats, irregardless of the depth of water. Critical habitats in the areas of the survey include 20 nm (37 km) surrounding all Steller sea lion haulouts and rookeries as well as the Seguam Pass Foraging Area and Bogoslof Foraging Area (see Figure 3 in the L-DEO application). If any Steller sea lions are found in or seen approaching the safety zone, L-DEO will shut-down the airgun. In addition, L-DEO will comply with the no-approach zone requirements of 50 CFR 223.202(a)(2)(i) for Steller sea lion rookeries, and the vessel will neither approach within 3 nm (5.6 km) of the rookeries or allow SPLs of 190 dB or greater within 3 nm (5.5 km) of a Steller sea lion rookery.

Start-Up Procedures

In order for airgun start-up to occur during day or night, the full safety radius must be visible for at least 30

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consecutive minutes. During night-time operations, if the entire safety radius is visible using vessel lights and night-vision devices (NVDs) (as may be the case in deep and intermediate waters), then start up of the airgun after a shut down may occur. However, lights and NVDs may not be very effective as a basis for monitoring the larger safety radii around the GI airgun operating in shallow water. Therefore in shallow water nighttime start ups of the GI gun from a shut-down condition are not authorized. However, if the GI airgun has been operational before nightfall, it can remain operational throughout the night, even though the entire safety radius may not be visible.

Comments on past IHAs raised the issue of prohibiting nighttime operations as prescribed mitigation. However, this is not practicable due to cost considerations and ship time schedules. The daily cost to the Federal Government to operate vessels such as Thompson is approximately $33,000-$35,000/day (Ljunngren, pers. comm. May 28, 2003). If the vessel was prohibited from operating during nighttime, each trip could require an additional three to five days to complete, or up to $175,000 more, depending on average daylight at the time of work.

If a seismic survey vessel is limited to daylight seismic operations, efficiency would also be much reduced. Without commenting specifically on how that would affect the present project, for seismic operators in general, a daylight-only requirement would be expected to result in one or more of the following outcomes: cancellation of potentially valuable seismic surveys; reduction in the total number of seismic cruises annually due to longer cruise durations; a need for additional vessels to conduct the seismic operations; or work conducted by non-U.S. operators or non-U.S. vessels when in waters not subject to U.S. law.

Marine Mammal Monitoring

L-DEO must have at least three visual observers on board the Thompson and at least two must be experienced marine mammal observers that NMFS has approved in advance of the start of the Aleutian Islands cruise. These observers will be on duty in shifts of no longer than 4 hours.

The visual observers will monitor marine mammals near the seismic source vessel during all daytime airgun operations, during any nighttime start-ups of the airgun (in intermediate and deep waters) and at night, whenever daytime monitoring resulted in one or more shut-down situations due to marine mammal presence. During daylight, vessel-based observers will watch for marine mammals near the seismic vessel during periods with shooting (including ramp-ups), and for 30 minutes prior to the planned start of airgun operations after a shut-down.

Use of multiple observers will increase the likelihood that marine mammals near the source vessel are detected. L-DEO bridge personnel will also assist in detecting marine mammals and implementing mitigation requirements whenever possible (they will be given instruction on how to do so), especially during ongoing operations at night when the designated observers are on stand-by and not required to be on watch at all times.

The observer(s) will watch for marine mammals from the highest practical vantage point on the vessel, which is either the bridge or the flying bridge. On the flying bridge of the Thompson, the observer's eye level will be 13.8 m (45.3 ft) above sea level, allowing for good visibility around the entire vessel (360[deg] for 2 observers, 310[deg] for one observer). The observer(s) will systematically scan the area around the vessel with reticle binoculars (e.g., 7 X 50 Fujinon) and with the naked eye during the daytime. At night, NVDs will be available (ITT F500 Series Generation 3 binocular-image intensifier or equivalent), when required. Laser range-finding binoculars (Leica L.F. 1200 laser rangefinder or equivalent) will be available to assist with distance estimation. The observers will be used to determine when a marine mammal is in or near the safety radii so that the required mitigation measures, such as course alteration and power-down or shut- down, can be implemented. If the GI-airgun is shut down, observers will maintain watch to determine when the animal is outside the safety radius.

Observers will not be on duty during ongoing seismic operations at night; bridge personnel will watch for marine mammals during this time and will call for the airgun to be shut-down if marine mammal(s) are observed in or about to enter the safety radii. However, a biological observer must be on standby at night and available to assist the bridge watch if marine mammals are detected. If the airgun is turned on at night (see previous section for restrictions), two marine mammal observers will monitor the safety zone for marine mammals for 30 minutes prior to ramp-up and during the ramp-up using either deck lighting or NVDs that will be available.

Post-Survey Monitoring

In addition, at times the biological observers will be able to conduct monitoring of most recently-run transect lines as the returns along a parallel transect track. This will provide the biological observers with opportunities to look for injured or dead marine mammals (although, for reasons noted elsewhere in this document, no injuries or mortalities are expected during this research cruise).

Taking into consideration the additional costs of prohibiting nighttime operations and the likely impact of the activity (including all mitigation and monitoring), NMFS has determined that the proposed mitigation and monitoring ensures that the activity will have the least practicable impact on the affected species or stocks. Marine mammals will have sufficient notice of a vessel approaching with an operating seismic airgun, thereby giving them an opportunity to avoid the approaching noise source; two marine mammal observers will be required to monitor the safety radii using shipboard lighting or NVDs for at least 30 minutes before ramp-up begins and verify that no marine mammals are in or approaching the safety radii; and start-up may not begin unless the entire safety radii are visible. Therefore as mentioned earlier, it is likely that the single GI-airgun will not be started-up from a shut-down at night when in waters shallower than 100 m (328 ft).

Reporting

L-DEO will submit a report to NMFS within 90 days after the end of the cruise, which is currently predicted to occur during July and August, 2005. The report will describe the operations that were conducted and the marine mammals that were detected. The report must provide full documentation of methods, results, and interpretation pertaining to all monitoring tasks. The report will summarize the dates and locations of seismic operations, marine mammal sightings (dates, times, locations, activities, associated seismic survey activities), and estimates of the amount and nature of potential take of marine mammals by harassment or in other ways.

Endangered Species Act (ESA)

NMFS has issued a biological opinion regarding the effects of this action on ESA-listed species and critical habitat under the jurisdiction of NMFS. That biological opinion concluded that this action is not likely to jeopardize the continued existence of listed species or result in the destruction or adverse

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modification of critical habitat. A copy of the Biological Opinion is available upon request (see ADDRESSES). On March 23, 2005, the USFWS determined that the proposed survey would not adversely affect sea otters or other species under its jurisdiction.

National Environmental Policy Act (NEPA)

The NSF has made a Finding of No Significant Impact (FONSI) determination based on information contained within its EA that implementation of the subject action is not a major Federal action having significant effects on the environment within the meaning of NEPA. NSF determined, therefore, that an environmental impact statement would not be prepared. On March 21, 2005 (70 FR 13466), NMFS noted that the NSF had prepared an EA for the Aleutian Island surveys and made this EA was available upon request. In accordance with NOAA Administrative Order 216-6 (Environmental Review Procedures for Implementing the National Environmental Policy Act, May 20, 1999), NMFS has reviewed the information contained in NSF's EA and determined that the NSF EA accurately and completely describes the proposed action alternative, and the potential impacts on marine mammals, endangered species, and other marine life that could be impacted by the preferred alternative and the other alternatives. Accordingly, NMFS adopted the NSF EA under 40 CFR 1506.3 and made its own FONSI. The NMFS FONSI also takes into consideration additional mitigation measures required by the IHA that are not in NSF's EA. Therefore, NMFS has determined that it is not necessary to issue a new EA, supplemental EA or an EIS for the issuance of an IHA to L-DEO for this activity. A copy of the EA and the NMFS FONSI for this activity is available upon request (see ADDRESSES).

Determinations

NMFS has determined that the impact of conducting the seismic survey in the Aleutian Islands in the North Pacific Ocean may result, at worst, in a temporary modification in behavior by certain species of marine mammals. This activity is expected to result in no more than a negligible impact on the affected species or stocks.

For reasons stated previously in this document, this determination is supported by (1) the likelihood that, given sufficient notice through relatively slow ship speed and ramp-up, marine mammals are expected to move away from a noise source that is annoying prior to its becoming potentially injurious; (2) recent research that indicates that TTS is unlikely (at least in delphinids) until levels closer to 200-205 dB re 1 microPa are reached rather than 180 dB re 1 microPa; (3) the fact that 200-205 dB isopleths would be well within 100 m (328 ft) of the vessel even in shallow water; and (4) the likelihood that marine mammal detection ability by trained observers is close to 100 percent during daytime and remains high at night to that distance from the seismic vessel. As a result, no take by injury or death is anticipated, and the potential for temporary or permanent hearing impairment is very low and will be avoided through the incorporation of the proposed mitigation measures mentioned in this document.

While the number of potential incidental harassment takes will depend on the distribution and abundance of marine mammals in the vicinity of the survey activity, the number of potential harassment takings is estimated to be small. In addition, the proposed seismic program will not interfere with any legal subsistence hunts, since seismic operations will not take place in subsistence whaling and sealing areas and will not affect marine mammals used for subsistence purposes.

The change of survey vessel and the differences in the timing of the summer 2005 survey are not expected to alter the impacts of the seismic survey on the wildlife resources in the area. The acoustic equipment on both vessels is similar and no substantial differences in impacts to the marine mammal species present and the environment are expected from the use of the Thompson instead of the R/V Kilo Moana. The description of the animal distributions and abundances in the study area is not expected to change over the approximately two month period of both the original and revised schedules. The take estimates provided in the application also apply to the revised schedule.

Authorization

NMFS has issued an IHA to L-DEO to take marine mammals, by harassment, incidental to conducting a low-intensity oceanographic seismic survey in the Aleutian Island area of the North Pacific Ocean, for a 1-year period, provided the mitigation, monitoring, and reporting requirements are undertaken.

Dated: July 28, 2005. James H. Lecky, Director, Office of Protected Resources, National Marine Fisheries Service.

[FR Doc. 05-15374 Filed 8-3-05; 8:45 am]

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