Federal Register / Vol. 70, No. 199 / Monday, October 17, 2005 / Notices 60287 

provide a complete citation or reference 

for retrieving the information. In 

addition, NMFS is seeking 

recommendations for study designs that 

could detect or predict the effects of 

research on right whales. 

For additional information about right 

whales, the permit process, and related 

information, please visit our website at 

http://www.nmfs.noaa.gov/pr/ 

rightwhale/. 

Scoping Meetings Agenda 

Public scoping meetings will be held 

at the following dates, times, and 

locations: 

1. Thursday, November 3, 2005, 3 – 6 

p.m., New Bedford Whaling Museum, 

Auditorium, 18 Johnny Cake Hill, New 

Bedford, MA; 

2. Saturday, December 10, 2005, 6:30 

– 9:30 p.m., Manchester Grand Hyatt, 

Elizabeth A Room, One Market Place, 

San Diego, CA; and 

3. Thursday, January 19, 2006, 1 – 4 

p.m., Silver Spring Metro Center, 

Building 4, Science Center, 1301 EastWest Highway, Silver Spring, MD. 

Comments will be accepted at these 

meetings as well as during the scoping 

period, and can be mailed to NMFS by 

January 31, 2006 (see FOR FURTHER

INFORMATION CONTACT). 

We will consider all comments 

received during the comment period. 

All hardcopy submissions must be 

unbound, on paper no larger than 81⁄2 by 

11 inches (216 by 279 mm), and suitable 

for copying and electronic scanning. We 

request that you include in your 

comments: 

(1) Your name and address; 

(2) Whether or not you would like to 

receive a copy of the Draft EIS; and 

(3) Any background documents to 

support your comments as you feel 

necessary. 

Special Accommodations 

These meetings are accessible to 

people with disabilities. Requests for 

sign language interpretation or other 

auxiliary aids should be directed to 

Carrie Hubard or Tammy Adams, 301- 

713-2289 (voice) or 301–427–2582 (fax), 

at least 5 days before the scheduled 

meeting date. 

Dated: October 12, 2005. 

Patrick Opay, 

Acting Chief, Permits, Conservation and 

Education Division, Office of Protected 

Resources, National Marine Fisheries Service. 

[FR Doc. 05–20715 Filed 10–14–05; 8:45 am] 

BILLING CODE 3510–22–S 

DEPARTMENT OF COMMERCE 

National Oceanic and Atmospheric 

Administration 

[I.D. 080905A] 

Small Takes of Marine Mammals 

Incidental to Specified Activities; LowEnergy Seismic Survey on the 

Louisville Ridge, Southwest Pacific 

Ocean 

AGENCY: National Marine Fisheries 

Service (NMFS), National Oceanic and 

Atmospheric Administration (NOAA), 

Commerce. 

ACTION: Notice of receipt of application 

and proposed incidental take 

authorization; request for comments. 

SUMMARY: NMFS has received an 

application from the Scripps Institution 

of Oceanography, (Scripps), a part of the 

University of California, for an 

Incidental Harassment Authorization 

(IHA) to take small numbers of marine 

mammals, by harassment, incidental to 

conducting an oceanographic survey in 

the southwestern Pacific Ocean (SWPO). 

Under the Marine Mammal Protection 

Act (MMPA), NMFS is requesting 

comments on its proposal to issue an 

authorization to Scripps to incidentally 

take, by harassment, small numbers of 

several species of cetaceans for a limited 

period of time during January and 

February, 2005. 

DATES: Comments and information must 

be received no later than November 16, 

2005. 

ADDRESSES: Comments on the 

application should be addressed to 

Steve Leathery, Chief, Permits, 

Conservation and Education Division, 

Office of Protected Resources, National 

Marine Fisheries Service, 1315 EastWest Highway, Silver Spring, MD 

20910–3225, or by telephoning the 

contact listed here. The mailbox address 

for providing email comments is 

PR1.080905A @noaa.gov. Comments 

sent via e-mail, including all 

attachments, must not exceed a 10– 

megabyte file size. A copy of the 

application (containing a list of the 

references used in this document) and 

an Environmental Assessment (EA) may 

be obtained by writing to this address or 

by telephoning the contact listed here 

and are also available at: http:// 

www.nmfs.noaa.gov/protlres/PR2/ 

SmalllTake/ 

smalltakelinfo.htm#applications. 

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) 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 

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 June 29, 2005, NMFS received an 

application from Scripps for the taking, 

by harassment, of several species of 

marine mammals incidental to 

conducting a low-energy marine seismic 

60288 Federal Register / Vol. 70, No. 199 / Monday, October 17, 2005 / Notices 

survey program during early 2006 in the 

SWPO. Scripps plans to conduct a 

seismic survey of several seamounts on 

the Louisville Ridge in the SWPO as 

part of the Integrated Ocean Drilling 

Program (IODP). As presently 

scheduled, the seismic survey will 

occur from about January 21 to February 

26, 2006. 

The purpose of the research program 

is to conduct a planned scientific rockdredging, magnetic, and seismic survey 

program of six seamounts of the 

Louisville seamount chain. The results 

will be used to: (1) Test hypotheses 

about the eruptive history of the 

submarine volcanoes, the subsequent 

formation (by subaerial erosion and 

submergence) of its many guyots, and 

motion of the hotspot plume; and (2) 

design an effective IODP cruise (not 

currently scheduled) to drill on 

carefully-selected seamounts. Included 

in the research planned for 2006 is 

scientific rock dredging, extensive totalfield and three-component magnetic 

surveys, the use of multi-beam and 

Chirp techniques to map the seafloor, 

and high-resolution seismic methods to 

image the subsea floor. Following the 

cruise, chemical and geochronologic 

analyses will be conducted on rocks 

from 25 sites. 

Description of the Activity 

The seismic surveys will involve one 

vessel. The source vessel, the R/V Roger 

Revelle, will deploy a pair of low-energy 

Generator-Injector (GI) airguns as an 

energy source (each with a discharge 

volume of 45 in3), plus a 450–m (1476–

ft) long, 48–channel, towed hydrophone 

streamer. As the airguns are towed along 

the survey lines, the receiving system 

will receive the returning acoustic 

signals. 

The program will consist of 

approximately 1840 km (994 nm) of 

surveys, including turns. Water depths 

within the seismic survey areas are 800–

2300 m (2625–7456 ft). The GI guns will 

be operated on a small grid (see inset in 

Figure 1 in Scripps (2006)) for about 28 

hours at each of 6 seamounts between 

approximately January 28 to February 

19, 2006. There will be additional 

seismic operations associated with 

equipment testing, start-up, and repeat 

coverage of any areas where initial data 

quality is sub-standard. 

The Revelle is scheduled to depart 

from Papeete, French Polynesia, on or 

about January 21, 2006, and to arrive at 

Wellington, New Zealand, on or about 

February 26, 2006. The GI guns will be 

used for about 28 hours on each of 6 

seamounts between about January 28th 

to February 19th. The exact dates of the 

activities may vary by a few days 

because of weather conditions, 

repositioning, streamer operations and 

adjustments, airgun deployment, or the 

need to repeat some lines if data quality 

is substandard. The overall area within 

which the seismic surveys will occur is 

located between approximately 25° and 

45°S., and between 155° and 175°W. 

The surveys will be conducted entirely 

in International Waters. 

In addition to the operations of the GI 

guns, a 3.5–kHz sub-bottom profiler and 

passive geophysical sensors to conduct 

total-field and three-component 

magnetic surveys will be operated 

during seismic surveys. A KongsbergSimrad EM–120 multi-beam sonar will 

be used continuously throughout the 

cruise. 

The energy to the airguns is 

compressed air supplied by compressors 

on board the source vessel. Seismic 

pulses will be emitted at intervals of 6–

10 seconds. At a speed of 7 knots (13 

km/h), the 6–10 sec spacing corresponds 

to a shot interval of approximately 21.5–

36 m (71–118 ft). 

The generator chamber of each GI 

gun, the one responsible for introducing 

the sound pulse into the ocean, is 45 

in3. The larger (105 in3) injector 

chamber injects air into the previouslygenerated bubble to maintain its shape, 

and does not introduce more sound into 

the water. The two 45/105 in3 GI guns 

will be towed 8 m (26.2 ft) apart side by 

side, 21 m (68.9 ft) behind the Revelle, 

at a depth of 2 m (6.6 ft). 

General-Injector Airguns 

Two GI-airguns will be used from the 

Revelle during the proposed program. 

These 2 GI-airguns have a zero to peak 

(peak) source output of 230.7 dB re 1 

microPascal-m (3.4 bar-m) and a peakto-peak (pk-pk) level of 235.9B (6.2 barm ). However, these downward-directed 

source levels do not represent actual 

sound levels that can be measured at 

any location in the water. Rather, they 

represent the level that would be found 

1 m (3.3 ft) from a hypothetical point 

source emitting the same total amount 

of sound as is emitted by the combined 

airguns in the airgun array. The actual 

received level at any location in the 

water near the airguns will not exceed 

the source level of the strongest 

individual source and actual levels 

experienced by any organism more than 

1 m (3.3 ft) from any GI gun will be 

significantly lower. 

Further, the root mean square (rms) 

received levels that are used as impact 

criteria for marine mammals (see 

Richardson et al., 1995) are not directly 

comparable to these peak or pk-pk 

values that are normally used to 

characterize source levels of airgun 

arrays. The measurement units used to 

describe airgun sources, peak or pk-pk 

decibels, are always higher than the rms 

decibels referred to in biological 

literature. For example, a measured 

received level of 160 dB rms in the far 

field would typically correspond to a 

peak 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, 2000). The precise difference 

between rms and peak or pk-pk values 

depends on the frequency content and 

duration of the pulse, among other 

factors. However, the rms level is 

always lower than the peak or pk-pk 

level for an airgun-type source. 

The depth at which the sources are 

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 

sources to be used in this project is 2.0 

m (6.6 ft), where the ambient pressure 

is approximately 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. Additional discussion of the 

characteristics of airgun pulses is 

provided in Scripps application and in 

previous Federal Register documents 

(see 69 FR 31792 (June 7, 2004) or 69 

FR 34996 (June 23, 2004)). 

Received sound levels have been 

modeled by Lamont-Doherty Earth 

Observatory (L-DEO) for a number of 

airgun configurations, including two 

45–in3 Nucleus G-guns (G guns), in 

relation to distance and direction from 

the airguns. The L-DEO model does not 

allow for bottom interactions, and is 

therefore most directly applicable to 

deep water. Based on the modeling, 

estimates of the maximum distances 

from the GI guns where sound levels of 

190, 180, 170, and 160 dB microPascalm (rms) are predicted to be received are 

shown in Table 1. Because the model 

results are for the G guns, which have 

more energy than GI guns of the same 

size, those distances are overestimates 

of the distances for the 45 in3 GI guns. 

Federal Register / Vol. 70, No. 199 / Monday, October 17, 2005 / Notices 60289 

TABLE 1. DISTANCES TO WHICH SOUND

LEVELS ≥190, 180, 170, AND 160 

DB RE 1 μPA (RMS) MIGHT BE RECEIVED FROM TWO 45–IN3 G GUNS, 

SIMILAR TO THE TWO 45–IN3 GI 

GUNS THAT WILL BE USED DURING

THE SEISMIC SURVEY IN THE SW PACIFIC OCEAN DURING JANUARY FEBRUARY 2006. DISTANCES ARE BASED

ON MODEL RESULTS PROVIDED BY LDEO. 

Water 

depth 

Estimated distances at received 

levels (m) 

190 dB 180 dB 170 dB 160 dB 

100–

1000 

m 15 60 188 525 

>1000 

m 10 40 125 350 

Some empirical data concerning the 

180-, and 160–dB distances have been 

acquired based on measurements during 

an acoustic verification study conducted 

by L-DEO in the northern Gulf of 

Mexico between May 27 and June 3, 

2003 (Tolstoy et al., 2004). Although the 

results are limited, the data showed that 

water depth affected the radii around 

the airguns where the received level 

would be 180 dB re 1 microPa (rms), 

NMFS’ current injury threshold safety 

criterion applicable to cetaceans (NMFS, 

2000). Similar depth-related variation is 

likely in the 190–dB distances 

applicable to pinnipeds. Correction 

factors were developed for water depths 

100–1000 m (328–3281 ft) and less than 

100 m (328 ft). The proposed survey 

will occur in depths 800–2300 m (2625–

7456 ft), so only the correction factor for 

intermediate water depths is relevant 

here. 

The empirical data indicate that, for 

deep water (>1000 m (3281 ft)), the LDEO model tends to overestimate the 

received sound levels at a given 

distance (Tolstoy et al., 2004). However, 

to be precautionary pending acquisition 

of additional empirical data, it is 

proposed that safety radii during airgun 

operations in deep water will be the 

values predicted by L-DEO’s model 

(Table 1). Therefore, the assumed 180- 

and 190–dB radii are 40 m (131 ft) and 

10 m (33 ft), respectively. 

Bathymetric Sonar and Sub-bottom 

Profiler 

The Kongsberg-Simrad EM120 multibeam sonar operates at 11.25–12.6 kHz, 

and is mounted in the hull of the 

Revelle. It operates in several modes, 

depending on water depth. In the 

proposed survey, it will be used in deep 

(>800–m) water, and will operate in 

‘‘deep’’ mode. The beamwidth is 1o or 

2o fore-aft and a total of 150° 

athwartship. Estimated maximum 

source levels are 239 and 233 dB at 1° 

and 2° beam widths, respectively. Each 

‘‘ping’’ consists of nine successive fanshaped transmissions, each ensonifying 

a sector that extends 1° or 2° fore-aft. In 

the ‘‘deep’’ mode, the total duration of 

the transmission into each sector is 15 

ms. The nine successive transmissions 

span an overall cross-track angular 

extent of about 150 degrees, with 16 ms 

gaps between the pulses for successive 

sectors. A receiver in the overlap area 

between two sectors would receive two 

15–ms pulses separated by a 16–ms gap. 

The ‘‘ping’’ interval varies with water 

depth, from approximately 5 sec at 1000 

m (3281 ft) to 20 sec at 4000 m (13123 

ft/2.2 nm). 

Sub-bottom Profiler – The sub-bottom 

profiler is normally operated to provide 

information about the sedimentary 

features and the bottom topography that 

is simultaneously being mapped by the 

multi-beam sonar. The energy from the 

sub-bottom profiler is directed 

downward by a 3.5–kHz transducer 

mounted in the hull of the Revelle. The 

output varies with water depth from 50 

watts in shallow water to 800 watts in 

deep water. Pulse interval is 1 second 

(s) but a common mode of operation is 

to broadcast five pulses at 1–s intervals 

followed by a 5–s pause. The 

beamwidth is approximately 30° and is 

directed downward. Maximum source 

output is 204 dB re 1 microPa (800 

watts) while normal source output is 

200 dB re 1 microPa (500 watts). Pulse 

duration will be 4, 2, or 1 ms, and the 

bandwith of pulses will be 1.0 kHz, 0.5 

kHz, or 0.25 kHz, respectively. 

Although the sound levels have not 

been measured directly for the subbottom profiler used by the Revelle, 

Burgess and Lawson (2000) measured 

sounds propagating more or less 

horizontally from a sub-bottom profiler 

similar to the Scripps unit with similar 

source output (i.e., 205 dB re 1 microPa 

m). For that profiler, the 160– and 180–

dB re 1 microPa (rms) radii in the 

horizontal direction were estimated to 

be, respectively, near 20 m (66 ft) and 

8 m (26 ft) from the source, as measured 

in 13 m (43 ft) water depth. The 

corresponding distances for an animal 

in the beam below the transducer would 

be greater, on the order of 180 m (591 

ft) and 18 m (59 ft) respectively, 

assuming spherical spreading. Thus the 

received level for the Scripps subbottom profiler would be expected to 

decrease to 160 and 180 dB about 160 

m (525 ft) and 16 m (52 ft) below the 

transducer, respectively, assuming 

spherical spreading. Corresponding 

distances in the horizontal plane would 

be lower, given the directionality of this 

source (30o beamwidth) and the 

measurements of Burgess and Lawson 

(2000). 

Characteristics of Airgun Pulses 

Discussion of the characteristics of 

airgun pulses was provided in several 

previous Federal Register documents 

(see 69 FR 31792 (June 7, 2004) or 69 

FR 34996 (June 23, 2004)) and is not 

repeated here. Reviewers are 

encouraged to read these earlier 

documents for additional information. 

Description of Habitat and Marine 

Mammals Affected by the Activity 

Forty species of cetacean, including 

31 odontocete (dolphins and small- and 

large-toothed whales) species and nine 

mysticete (baleen whales) species, are 

believed by scientists to occur in the 

southwest Pacific in the proposed 

seismic survey area. More detailed 

information on these species is 

contained in the Scripps application 

and the National Science Foundation 

(NSF) EA which are available at: http:// 

www.nmfs.noaa.gov/protlres/PR2/ 

SmalllTake/ 

smalltakelinfo.htm#applications. 

Table 2 in both the Scripps application 

and NSF EA summarizes the habitat, 

occurrence, and regional population 

estimate for these species. The following 

species may be affected by this lowintensity seismic survey: Sperm whale, 

pygmy and dwarf sperm whales, 

southern bottlenose whale, Arnoux’s 

beaked whale, Cuvier’s beaked whale, 

Shepherd’s beaked whale, mesoplodont 

beaked whales (Andrew’s beaked whale, 

Blainville’s beaked whale, gingkotoothed whale, Gray’s beaked whale, 

Hector’s beaked whale, spade-toothed 

whale, strap-toothed whale), melonheaded whale, pygmy killer whale, false 

killer whale, killer whale, long-finned 

pilot whale, short-finned pilot whale, 

rough-toothed dolphin, bottlenose 

dolphin, pantropical spotted dolphin, 

spinner dolphin, striped dolphin, shortbeaked common dolphin, hourglass 

dolphin, Fraser’s dolphin , Risso’s 

dolphin, southern right whale dolphin, 

spectacled porpoise, humpback whale, 

southern right whale, pygmy right 

whale, common minke whale, Antarctic 

minke whale. Bryde’s whale, sei whale 

, fin whale and blue whale. Because the 

proposed survey area spans a wide 

range of latitudes (25–45° S), tropical, 

temperate, and possibly polar species 

are all likely to be found there. The 

survey area is all in deep-water habitat 

but is close to oceanic island (Kermadec 

Islands) habitats, so both coastal and 

oceanic species might be encountered. 

60290 Federal Register / Vol. 70, No. 199 / Monday, October 17, 2005 / Notices 

However, abundance and density 

estimates of cetaceans found there are 

provided for reference only, and are not 

necessarily the same as those that likely 

occur in the survey area. 

Five species of pinnipeds could 

potentially occur in the proposed 

seismic survey area: southern elephant 

seal, leopard seal, crabeater seal, 

Antarctic fur seal, and the sub-Antarctic 

fur seal. All are likely to be rare, if they 

occur at all, as their normal 

distributions are south of the Scripps 

survey area. Outside the breeding 

season, however, they disperse widely 

in the open ocean (Boyd, 2002; King, 

1982; Rogers, 2002). Only three species 

of pinniped are known to wander 

regularly into the area (Reeves et al., 

1999): the Antarctic fur seal, the subAntarctic fur seal, and the leopard seal. 

Leopard seals are seen as far north as 

the Cook Islands (Rogers, 2002). 

Potential Effects on Marine Mammals 

As outlined in several previous NMFS 

documents, the effects of noise on 

marine mammals are highly variable, 

and can be categorized as follows (based 

on Richardson et al., 1995): 

(1) The noise may be too weak to be 

heard at the location of the animal (i.e., 

lower than the prevailing ambient noise 

level, the hearing threshold of the 

animal at relevant frequencies, or both); 

(2) The noise may be audible but not 

strong enough to elicit any overt 

behavioral response; 

(3) The noise may elicit reactions of 

variable conspicuousness and variable 

relevance to the well being of the 

marine mammal; these can range from 

temporary alert responses to active 

avoidance reactions such as vacating an 

area at least until the noise event ceases; 

(4) Upon repeated exposure, a marine 

mammal may exhibit diminishing 

responsiveness (habituation), or 

disturbance effects may persist; the 

latter is most likely with sounds that are 

highly variable in characteristics, 

infrequent and unpredictable in 

occurrence, and associated with 

situations that a marine mammal 

perceives as a threat; 

(5) Any anthropogenic noise that is 

strong enough to be heard has the 

potential to reduce (mask) the ability of 

a marine mammal to hear natural 

sounds at similar frequencies, including 

calls from conspecifics, and underwater 

environmental sounds such as surf 

noise; 

(6) If mammals remain in an area 

because it is important for feeding, 

breeding or some other biologically 

important purpose even though there is 

chronic exposure to noise, it is possible 

that there could be noise-induced 

physiological stress; this might in turn 

have negative effects on the well-being 

or reproduction of the animals involved; 

and 

(7) Very strong sounds have the 

potential to cause temporary or 

permanent reduction in hearing 

sensitivity. In terrestrial mammals, and 

presumably marine mammals, received 

sound levels must far exceed the 

animal’s hearing threshold for there to 

be any temporary threshold shift (TTS) 

in its hearing ability. For transient 

sounds, the sound level necessary to 

cause TTS is inversely related to the 

duration of the sound. Received sound 

levels must be even higher for there to 

be risk of permanent hearing 

impairment. In addition, intense 

acoustic or explosive events may cause 

trauma to tissues associated with organs 

vital for hearing, sound production, 

respiration and other functions. This 

trauma may include minor to severe 

hemorrhage. 

Effects of Seismic Surveys on Marine 

Mammals 

The Scripps’ application provides the 

following information on what is known 

about the effects on marine mammals of 

the types of seismic operations planned 

by Scripps. The types of effects 

considered here are (1) tolerance, (2) 

masking of natural sounds, (2) 

behavioral disturbance, and (3) potential 

hearing impairment and other nonauditory physical effects (Richardson et 

al., 1995). Given the relatively small size 

of the airguns planned for the present 

project, its effects are anticipated to be 

considerably less than would be the 

case with a large array of airguns. 

Scripps and NMFS believe it is very 

unlikely that there would be any cases 

of temporary or especially permanent 

hearing impairment, or non-auditory 

physical effects. Also, behavioral 

disturbance is expected to be limited to 

distances less than 520 m (1706 ft) from 

the source, the zone calculated for 160 

dB or the onset of Level B harassment. 

Additional discussion on speciesspecific effects can be found in the 

Scripps application. 

Tolerance 

Numerous studies (referenced in 

Scripps, 2005) have shown that pulsed 

sounds from airguns are often readily 

detectable in the water at distances of 

many kilometers, but that marine 

mammals at distances more than a few 

kilometers from operating seismic 

vessels often show no apparent 

response. That is often true even in 

cases when the pulsed sounds must be 

readily audible to the animals based on 

measured received levels and the 

hearing sensitivity of that mammal 

group. However, most measurements of 

airgun sounds that have been reported 

concerned sounds from larger arrays of 

airguns, whose sounds would be 

detectable farther away than that 

planned for use in the proposed survey. 

Although various baleen whales, 

toothed whales, and pinnipeds have 

been shown to react behaviorally to 

airgun pulses under some conditions, at 

other times mammals of all three types 

have shown no overt reactions. In 

general, pinnipeds and small 

odontocetes seem to be more tolerant of 

exposure to airgun pulses than are 

baleen whales. Given the relatively 

small, low-energy airgun source 

planned for use in this project, 

mammals are expected to tolerate being 

closer to this source than would be the 

case for a larger airgun source typical of 

most seismic surveys. 

Masking 

Masking effects of pulsed sounds 

(even from large arrays of airguns) on 

marine mammal calls and other natural 

sounds are expected to be limited (due 

in part to the small size of the GI 

airguns), although there are very few 

specific data on this. Given the small 

acoustic source planned for use in the 

SWPO, there is even less potential for 

masking of baleen or sperm whale calls 

during the present research than in most 

seismic surveys (Scripps, 2005). GIairgun seismic sounds are short pulses 

generally occurring for less than 1 sec 

every 6–10 seconds or so. The 6–10 sec 

spacing corresponds to a shot interval of 

approximately 21.5–36 m (71–118 ft). 

Sounds from the multi-beam sonar are 

very short pulses, occurring for 15 msec 

once every 5 to 20 sec, depending on 

water depth. 

Some whales are known to continue 

calling in the presence of seismic 

pulses. Their calls can be heard between 

the seismic pulses (Richardson et al., 

1986; McDonald et al., 1995, Greene et 

al., 1999). Although there has been one 

report that sperm whales cease calling 

when exposed to pulses from a very 

distant seismic ship (Bowles et al., 

1994), a recent study reports that sperm 

whales continued calling in the 

presence of seismic pulses (Madsen et 

al., 2002). Given the relatively small 

source planned for use during this 

survey, there is even less potential for 

masking of sperm whale calls during the 

present study than in most seismic 

surveys. Masking effects of seismic 

pulses are expected to be negligible in 

the case of the smaller odontocete 

cetaceans, given the intermittent nature 

of seismic pulses and the relatively low 

source level of the airguns to be used in 

Federal Register / Vol. 70, No. 199 / Monday, October 17, 2005 / Notices 60291 

the SWPO. Also, the sounds important 

to small odontocetes are predominantly 

at much higher frequencies than are 

airgun sounds. 

Most of the energy in the sound 

pulses emitted by airgun arrays is at low 

frequencies, with strongest spectrum 

levels below 200 Hz and considerably 

lower spectrum levels above 1000 Hz. 

Among marine mammals, these low 

frequencies are mainly used by 

mysticetes, but generally not by 

odontocetes or pinnipeds. An industrial 

sound source will reduce the effective 

communication or echolocation 

distance only if its frequency is close to 

that of the marine mammal signal. If 

little or no overlap occurs between the 

industrial noise and the frequencies 

used, as in the case of many marine 

mammals relative to airgun sounds, 

communication and echolocation are 

not expected to be disrupted. 

Furthermore, the discontinuous nature 

of seismic pulses makes significant 

masking effects unlikely even for 

mysticetes. 

A few cetaceans are known to 

increase the source levels of their calls 

in the presence of elevated sound levels, 

or possibly to shift their peak 

frequencies in response to strong sound 

signals (Dahlheim, 1987; Au, 1993; 

Lesage et al., 1999; Terhune, 1999; as 

reviewed in Richardson et al., 1995). 

These studies involved exposure to 

other types of anthropogenic sounds, 

not seismic pulses, and it is not known 

whether these types of responses ever 

occur upon exposure to seismic sounds. 

If so, these adaptations, along with 

directional hearing, pre-adaptation to 

tolerate some masking by natural 

sounds (Richardson et al., 1995) and the 

relatively low-power acoustic sources 

being used in this survey, would all 

reduce the importance of masking 

marine mammal vocalizations. 

Disturbance by Seismic Surveys 

Disturbance includes a variety of 

effects, including subtle changes in 

behavior, more conspicuous dramatic 

changes in behavioral activities, and 

displacement. However, there are 

difficulties in defining which marine 

mammals should be counted as ‘‘taken 

by harassment’’. For many species and 

situations, scientists do not have 

detailed information about their 

reactions to noise, including reactions to 

seismic (and sonar) pulses. Behavioral 

reactions of marine mammals to sound 

are difficult to predict. Reactions to 

sound, if any, depend on species, state 

of maturity, experience, current activity, 

reproductive state, time of day, and 

many other factors. If a marine mammal 

does react to an underwater sound by 

changing its behavior or moving a small 

distance, the impacts of the change may 

not rise to the level of a disruption of 

a behavioral pattern. However, if a 

sound source would displace marine 

mammals from an important feeding or 

breeding area, such a disturbance would 

likely constitute Level B harassment 

under the MMPA. Given the many 

uncertainties in predicting the quantity 

and types of impacts of noise on marine 

mammals, scientists often resort to 

estimating how many mammals may be 

present within a particular distance of 

industrial activities or exposed to a 

particular level of industrial sound. 

With the possible exception of beaked 

whales, NMFS believes that this is a 

conservative approach and likely 

overestimates the numbers of marine 

mammals that are affected in some 

biologically important manner. 

The sound exposure criteria used to 

estimate how many marine mammals 

might be harassed behaviorally by the 

seismic survey are based on behavioral 

observations during studies of several 

species. However, information is lacking 

for many species. Detailed information 

on potential disturbance effects on 

baleen whales, toothed whales, and 

pinnipeds can be found on pages 33–37 

and Appendix A in Scripps’s SWPO 

application. 

Hearing Impairment and Other Physical 

Effects 

Temporary or permanent hearing 

impairment is a possibility when marine 

mammals are exposed to very strong 

sounds, but there has been no specific 

documentation of these effects for 

marine mammals exposed to airgun 

pulses. Current NMFS policy 

precautionarily sets impulsive sounds 

equal to or greater than 180 and 190 dB 

re 1 microPa (rms) as the exposure 

thresholds for onset of Level A 

harassment for cetaceans and pinnipeds, 

respectively (NMFS, 2000). Those 

criteria have been used in defining the 

safety (shut-down) radii for seismic 

surveys. However, those criteria were 

established before there were any data 

on the minimum received levels of 

sounds necessary to cause auditory 

impairment in marine mammals. As 

discussed in the Scripps application 

and summarized here, 

1. The 180–dB criterion for cetaceans 

is probably quite precautionary, i.e., 

lower than necessary to avoid TTS let 

alone permanent auditory injury, at 

least for delphinids. 

2. The minimum sound level 

necessary to cause permanent hearing 

impairment is higher, by a variable and 

generally unknown amount, than the 

level that induces barely-detectable 

TTS. 

3. The level associated with the onset 

of TTS is often considered to be a level 

below which there is no danger of 

permanent damage. 

Given the small size of the two 45 in3

GI-airguns, along with the proposed 

monitoring and mitigation measures, 

there is little likelihood that any marine 

mammals will be exposed to sounds 

sufficiently strong to cause even the 

mildest (and reversible) form of hearing 

impairment. Several aspects of the 

planned monitoring and mitigation 

measures for this project are designed to 

detect marine mammals occurring near 

the 2 GI-airguns (and bathymetric 

sonar), and to avoid exposing them to 

sound pulses that might (at least in 

theory) cause hearing impairment. In 

addition, research and monitoring 

studies on gray whales, bowhead whales 

and other cetacean species indicate that 

many cetaceans are likely to show some 

avoidance of the area with ongoing 

seismic operations. In these cases, the 

avoidance responses of the animals 

themselves will reduce or avoid the 

possibility of hearing impairment. 

Non-auditory physical effects may 

also occur in marine mammals exposed 

to strong underwater pulsed sound. 

Possible types of non-auditory 

physiological effects or injuries that 

theoretically might occur in mammals 

close to a strong sound source include 

stress, neurological effects, bubble 

formation, resonance effects, and other 

types of organ or tissue damage. It is 

possible that some marine mammal 

species (i.e., beaked whales) may be 

especially susceptible to injury and/or 

stranding when exposed to strong 

pulsed sounds. However, Scripps and 

NMFS believe that it is especially 

unlikely that any of these non-auditory 

effects would occur during the proposed 

survey given the small size of the 

acoustic sources, the brief duration of 

exposure of any given mammal, and the 

proposed mitigation and monitoring 

measures. The following paragraphs 

discuss the possibility of TTS, 

permanent threshold shift (PTS), and 

non-auditory physical effects. 

TTS 

TTS is the mildest form of hearing 

impairment that can occur during 

exposure to a strong sound (Kryter, 

1985). When an animal experiences 

TTS, its hearing threshold rises and a 

sound must be stronger in order to be 

heard. TTS can last from minutes or 

hours to (in cases of strong TTS) days. 

Richardson et al. (1995) note that the 

magnitude of TTS depends on the level 

and duration of noise exposure, among 

60292 Federal Register / Vol. 70, No. 199 / Monday, October 17, 2005 / Notices 

other considerations. For sound 

exposures at or somewhat above the 

TTS threshold, hearing sensitivity 

recovers rapidly after exposure to the 

noise ends. Little data on sound levels 

and durations necessary to elicit mild 

TTS have been obtained for marine 

mammals. 

For toothed whales exposed to single 

short pulses, the TTS threshold appears 

to be, to a first approximation, a 

function of the energy content of the 

pulse (Finneran et al., 2002). Given the 

available data, the received level of a 

single seismic pulse might need to be on 

the order of 210 dB re 1 microPa rms 

(approx. 221–226 dB pk pk) in order to 

produce brief, mild TTS. Exposure to 

several seismic pulses at received levels 

near 200 205 dB (rms) might result in 

slight TTS in a small odontocete, 

assuming the TTS threshold is (to a first 

approximation) a function of the total 

received pulse energy (Finneran et al., 

2002). Seismic pulses with received 

levels of 200 205 dB or more are usually 

restricted to a zone of no more than 100 

m (328 ft) around a seismic vessel 

operating a large array of airguns. 

Because of the small airgun source 

planned for use during this project, such 

sound levels would be limited to 

distances within a few meters directly 

astern of the Revelle. 

There are no data, direct or indirect, 

on levels or properties of sound that are 

required to induce TTS in any baleen 

whale. However, TTS is not expected to 

occur during this survey given the small 

size of the source limiting these sound 

pressure levels to the immediate 

proximity of the vessel, and the strong 

likelihood that baleen whales would 

avoid the approaching airguns (or 

vessel) before being exposed to levels 

high enough for there to be any 

possibility of TTS. 

TTS thresholds for pinnipeds exposed 

to brief pulses (single or multiple) have 

not been measured, although exposures 

up to 183 dB re 1 microPa (rms) have 

been shown to be insufficient to induce 

TTS in California sea lions (Finneran et 

al., 2003). However, prolonged 

exposures show that some pinnipeds 

may incur TTS at somewhat lower 

received levels than do small 

odontocetes exposed for similar 

durations (Kastak et al., 1999; Ketten et 

al., 2001; Au et al., 2000). For this 

research cruise therefore, TTS is 

unlikely for pinnipeds. 

A marine mammal within a zone with 

a radius of ≤100 m (≤328 ft) around a 

typical large array of operating airguns 

might be exposed to a few seismic 

pulses with levels of ≥205 dB, and 

possibly more pulses if the mammal 

moved with the seismic vessel. Also, 

around smaller arrays, such as the 2 GIairgun array proposed for use during 

this survey, a marine mammal would 

need to be even closer to the source to 

be exposed to levels greater than or 

equal to 205 dB. However, as noted 

previously, most cetacean species tend 

to avoid operating airguns, although not 

all individuals do so. In addition, 

ramping up airgun arrays, which is now 

standard operational protocol for U.S. 

and some foreign seismic operations, 

should allow cetaceans to move away 

from the seismic source and to avoid 

being exposed to the full acoustic 

output of the airgun array. Even with a 

large airgun array, it is unlikely that 

these cetaceans would be exposed to 

airgun pulses at a sufficiently high level 

for a sufficiently long period to cause 

more than mild TTS, given the relative 

movement of the vessel and the marine 

mammal. However, with a large airgun 

array, TTS would be more likely in any 

odontocetes that bow-ride or otherwise 

linger near the airguns. While bowriding, odontocetes would be at or above 

the surface, and thus not exposed to 

strong sound pulses given the pressurerelease effect at the surface. However, 

bow-riding animals generally dive 

below the surface intermittently. If they 

did so while bow-riding near airguns, 

they would be exposed to strong sound 

pulses, possibly repeatedly. During this 

project, the anticipated 180–dB radius is 

less than 60 m (197 ft), the array is 

towed about 21 m (69 ft) behind the 

Revelle, the bow of the Revelle will be 

about 104 m (341 ft) ahead of the 

airguns, and the 205–dB radius would 

be less than 50 m (165 ft). Thus, TTS 

would not be expected in the case of 

odontocetes bow riding during airgun 

operations, and if some cetaceans did 

incur TTS through exposure to airgun 

sounds, it would very likely be a 

temporary and reversible phenomenon. 

NMFS believes that, to avoid Level A 

harassment, cetaceans should not be 

exposed to pulsed underwater noise at 

received levels exceeding 180 dB re 1 

microPa (rms). The corresponding limit 

for pinnipeds has been set at 190 dB. 

The predicted 180- and 190–dB 

distances for the airgun arrays operated 

by Scripps during this activity are 

summarized in Table 1 in this 

document. These sound levels are not 

considered to be the levels at or above 

which TTS might occur. Rather, they are 

the received levels above which, in the 

view of a panel of bioacoustics 

specialists convened by NMFS (at a time 

before TTS measurements for marine 

mammals started to become available), 

one could not be certain that there 

would be no injurious effects, auditory 

or otherwise, to marine mammals. As 

noted here, TTS data that are now 

available imply that, at least for 

dolphins, TTS is unlikely to occur 

unless the dolphins are exposed to 

airgun pulses substantially stronger than 

180 dB re 1 microPa (rms). 

It has also been shown that most 

whales tend to avoid ships and 

associated seismic operations. Thus, 

whales will likely not be exposed to 

such high levels of airgun sounds. 

Because of the relatively slow ship 

speed, any whales close to the trackline 

could move away before the sounds 

become sufficiently strong for there to 

be any potential for hearing impairment. 

Therefore, there is little potential for 

whales being close enough to an array 

to experience TTS. In addition, ramping 

up the airgun array, which has become 

standard operational protocol for many 

seismic operators including Scripps, 

should allow cetaceans to move away 

from the seismic source and to avoid 

being exposed to the full acoustic 

output of the GI airguns. 

Permanent Threshold Shift (PTS) 

When PTS occurs there is physical 

damage to the sound receptors in the 

ear. In some cases there can be total or 

partial deafness, while in other cases the 

animal has an impaired ability to hear 

sounds in specific frequency ranges. 

Although there is no specific evidence 

that exposure to pulses of airgun sounds 

can cause PTS in any marine mammals, 

even with the largest airgun arrays, 

physical damage to a mammal’s hearing 

apparatus can potentially occur if it is 

exposed to sound impulses that have 

very high peak pressures, especially if 

they have very short rise times (time 

required for sound pulse to reach peak 

pressure from the baseline pressure). 

Such damage can result in a permanent 

decrease in functional sensitivity of the 

hearing system at some or all 

frequencies. 

Single or occasional occurrences of 

mild TTS are not indicative of 

permanent auditory damage in 

terrestrial mammals. However, very 

prolonged exposure to sound strong 

enough to elicit TTS, or shorter-term 

exposure to sound levels well above the 

TTS threshold, can cause PTS, at least 

in terrestrial mammals (Kryter, 1985). 

Relationships between TTS and PTS 

thresholds have not been studied in 

marine mammals but are assumed to be 

similar to those in humans and other 

terrestrial mammals. The low-tomoderate levels of TTS that have been 

induced in captive odontocetes and 

pinnipeds during recent controlled 

studies of TTS have been confirmed to 

be temporary, with no measurable 

Federal Register / Vol. 70, No. 199 / Monday, October 17, 2005 / Notices 60293 

residual PTS (Kastak et al., 1999; 

Schlundt et al., 2000; Finneran et al., 

2002; Nachtigall et al., 2003). In 

terrestrial mammals, the received sound 

level from a single non-impulsive sound 

exposure must be far above the TTS 

threshold for any risk of permanent 

hearing damage (Kryter, 1994; 

Richardson et al., 1995). For impulse 

sounds with very rapid rise times (e.g., 

those associated with explosions or 

gunfire), a received level not greatly in 

excess of the TTS threshold may start to 

elicit PTS. Rise times for airgun pulses 

are rapid, but less rapid than for 

explosions. 

Some factors that contribute to onset 

of PTS are as follows: (1) exposure to 

single very intense noises, (2) repetitive 

exposure to intense sounds that 

individually cause TTS but not PTS, 

and (3) recurrent ear infections or (in 

captive animals) exposure to certain 

drugs. 

Cavanagh (2000) reviewed the 

thresholds used to define TTS and PTS. 

Based on his review and SACLANT 

(1998), it is reasonable to assume that 

PTS might occur at a received sound 

level 20 dB or more above that which 

induces mild TTS. However, for PTS to 

occur at a received level only 20 dB 

above the TTS threshold, it is probable 

that the animal would have to be 

exposed to the strong sound for an 

extended period. 

Sound impulse duration, peak 

amplitude, rise time, and number of 

pulses are the main factors thought to 

determine the onset and extent of PTS. 

Ketten (1994) noted that the criteria for 

differentiating the sound pressure levels 

that result in PTS (or TTS) are location 

and species-specific. PTS effects may 

also be influenced strongly by the health 

of the receiver’s ear. 

Given that marine mammals are 

unlikely to be exposed to received levels 

of seismic pulses that could cause TTS, 

it is highly unlikely that they would 

sustain permanent hearing impairment. 

If we assume that the TTS threshold for 

odontocetes for exposure to a series of 

seismic pulses may be on the order of 

220 dB re 1 microPa (pk-pk) 

(approximately 204 dB re 1 microPa 

rms), then the PTS threshold might be 

about 240 dB re 1 microPa (pk-pk). In 

the units used by geophysicists, this is 

10 bar-m. Such levels are found only in 

the immediate vicinity of the largest 

airguns (Richardson et al., 1995; 

Caldwell and Dragoset, 2000). However, 

it is very unlikely that an odontocete 

would remain within a few meters of a 

large airgun for sufficiently long to incur 

PTS. The TTS (and thus PTS) thresholds 

of baleen whales and pinnipeds may be 

lower, and thus may extend to a 

somewhat greater distance from the 

source. However, baleen whales 

generally avoid the immediate area 

around operating seismic vessels, so it 

is unlikely that a baleen whale could 

incur PTS from exposure to airgun 

pulses. Some pinnipeds do not show 

strong avoidance of operating airguns. 

In summary, it is highly unlikely that 

marine mammals could receive sounds 

strong enough (and over a sufficient 

period of time) to cause permanent 

hearing impairment during this project. 

In the proposed project marine 

mammals are unlikely to be exposed to 

received levels of seismic pulses strong 

enough to cause TTS, and because of the 

higher level of sound necessary to cause 

PTS, it is even less likely that PTS could 

occur. This is due to the fact that even 

levels immediately adjacent to the 2 GIairguns may not be sufficient to induce 

PTS because the mammal would not be 

exposed to more than one strong pulse 

unless it swam alongside an airgun for 

a period of time. 

Strandings and Mortality 

Marine mammals close to underwater 

detonations of high explosives can be 

killed or severely injured, and the 

auditory organs are especially 

susceptible to injury (Ketten et al., 1993; 

Ketten, 1995). Airgun pulses are less 

energetic and have slower rise times. 

While there is no documented evidence 

that airgun arrays can cause serious 

injury, death, or stranding, the 

association of mass strandings of beaked 

whales with naval exercises and an LDEO seismic survey in 2002 have raised 

the possibility that beaked whales may 

be especially susceptible to injury and/ 

or stranding when exposed to strong 

pulsed sounds. Information on recent 

beaked whale strandings may be found 

in Appendix A of the Scripps 

application and in several previous 

Federal Register documents (see 69 FR 

31792 (June 7, 2004) or 69 FR 34996 

(June 23, 2004)). Reviewers are 

encouraged to read these documents for 

additional information. 

It is important to note that seismic 

pulses and mid-frequency sonar pulses 

are quite different. Sounds produced by 

the types of airgun arrays used to profile 

sub-sea geological structures are 

broadband with most of the energy 

below 1 kHz. Typical military midfrequency sonars operate at frequencies 

of 2 to 10 kHz, generally with a 

relatively narrow bandwidth at any one 

time (though the center frequency may 

change over time). Because seismic and 

sonar sounds have considerably 

different characteristics and duty cycles, 

it is not appropriate to assume that there 

is a direct connection between the 

effects of military sonar and seismic 

surveys on marine mammals. However, 

evidence that sonar pulses can, in 

special circumstances, lead to physical 

damage and, indirectly, mortality 

suggests that caution is warranted when 

dealing with exposure of marine 

mammals to any high-intensity pulsed 

sound. 

In addition to the sonar-related 

strandings, there was a September, 2002 

stranding of two Cuvier’s beaked whales 

in the Gulf of California (Mexico) when 

a seismic survey by the R/V Maurice 

Ewing was underway in the general area 

(Malakoff, 2002). The airgun array in 

use during that project was the Ewing’s 

20–gun 8490–in3 array. This might be a 

first indication that seismic surveys can 

have effects, at least on beaked whales, 

similar to the suspected effects of naval 

sonars. However, the evidence linking 

the Gulf of California strandings to the 

seismic surveys is inconclusive, and to 

date, is not based on any physical 

evidence (Hogarth, 2002; Yoder, 2002). 

The ship was also operating its multibeam bathymetric sonar at the same 

time but this sonar had much less 

potential than these naval sonars to 

affect beaked whales. Although the link 

between the Gulf of California 

strandings and the seismic (plus multibeam sonar) survey is inconclusive, this 

plus the various incidents involving 

beaked whale strandings associated 

with naval exercises suggests a need for 

caution in conducting seismic surveys 

in areas occupied by beaked whales. 

However, the present project will 

involve a much smaller sound source 

than used in typical seismic surveys. 

That, along with the monitoring and 

mitigation measures planned for this 

cruise are expected to eliminate any 

possibility for strandings and mortality. 

Non-auditory Physiological Effects 

Possible types of non-auditory 

physiological effects or injuries that 

might theoretically occur in marine 

mammals exposed to strong underwater 

sound might include stress, neurological 

effects, bubble formation, resonance 

effects, and other types of organ or 

tissue damage. There is no evidence that 

any of these effects occur in marine 

mammals exposed to sound from airgun 

arrays (even large ones). However, there 

have been no direct studies of the 

potential for airgun pulses to elicit any 

of these effects. If any such effects do 

occur, they would probably be limited 

to unusual situations when animals 

might be exposed at close range for 

unusually long periods. 

It is doubtful that any single marine 

mammal would be exposed to strong 

seismic sounds for sufficiently long that 

60294 Federal Register / Vol. 70, No. 199 / Monday, October 17, 2005 / Notices 

significant physiological stress would 

develop. That is especially so in the 

case of the present project where the 

airguns are small, the ship’s speed is 

relatively fast (6 knots or approximately 

11 km/h), and, except while on a 

seismic station, the survey lines are 

widely spaced with little or no overlap. 

Gas-filled structures in marine 

animals have an inherent fundamental 

resonance frequency. If stimulated at 

that frequency, the ensuing resonance 

could cause damage to the animal. 

There may also be a possibility that high 

sound levels could cause bubble 

formation in the blood of diving 

mammals that in turn could cause an air 

embolism, tissue separation, and high, 

localized pressure in nervous tissue 

(Gisner (ed), 1999; Houser et al., 2001). 

In April 2002, a workshop (Gentry 

[ed.] 2002) was held to discuss whether 

the stranding of beaked whales in the 

Bahamas in 2000 (Balcomb and 

Claridge, 2001; NOAA and USN, 2001) 

might have been related to air cavity 

resonance or bubble formation in tissues 

caused by exposure to noise from naval 

sonar. A panel of experts concluded that 

resonance in air-filled structures was 

not likely to have caused this stranding. 

Among other reasons, the air spaces in 

marine mammals are too large to be 

susceptible to resonant frequencies 

emitted by mid- or low-frequency sonar; 

lung tissue damage has not been 

observed in any mass, multi-species 

stranding of beaked whales; and the 

duration of sonar pings is likely too 

short to induce vibrations that could 

damage tissues (Gentry (ed.), 2002). 

Opinions were less conclusive about the 

possible role of gas (nitrogen) bubble 

formation/growth in the Bahamas 

stranding of beaked whales. 

Until recently, it was assumed that 

diving marine mammals are not subject 

to decompression injury (the bends) or 

air embolism. However, a short paper 

concerning beaked whales stranded in 

the Canary Islands in 2002 suggests that 

cetaceans might be subject to 

decompression injury in some situations 

(Jepson et al., 2003). If so, that might 

occur if they ascend unusually quickly 

when exposed to aversive sounds. 

However, the interpretation that 

strandings are related to decompression 

injury is unproven (Piantadosi and 

Thalmann, 2004; Fernandez et al., 

2004). Even if that effect can occur 

during exposure to mid-frequency 

sonar, there is no evidence that this type 

of effect occurs in response to lowfrequency airgun sounds. It is especially 

unlikely in the case of this project 

involving only two small, low-intensity 

GI-airguns. 

In summary, little is known about the 

potential for seismic survey sounds to 

cause either auditory impairment or 

other non-auditory physical effects in 

marine mammals. Available data 

suggest that such effects, if they occur 

at all, would be limited to short 

distances from the sound source. 

However, the available data do not 

allow for meaningful quantitative 

predictions of the numbers (if any) of 

marine mammals that might be affected 

in these ways. Marine mammals that 

show behavioral avoidance of seismic 

vessels, including most baleen whales, 

some odontocetes, and some pinnipeds, 

are unlikely to incur auditory 

impairment or other physical effects. 

Also, the planned mitigation and 

monitoring measures are expected to 

minimize any possibility of serious 

injury, mortality or strandings. 

Possible Effects of Mid-frequency Sonar 

Signals 

A multi-beam bathymetric sonar 

(Simrad EM120, 11.25–12.6 kHz) and a 

sub-bottom profiler will be operated 

from the source vessel essentially 

continuously during much of the 

planned survey. Details about these 

sonars were provided previously in this 

document. 

Navy sonars that have been linked to 

avoidance reactions and stranding of 

cetaceans generally: (1) are more 

powerful than the Simrad EM120 sonar; 

(2) have a longer pulse duration; and (3) 

are directed close to horizontally (vs. 

downward for the Simrad EM120). The 

area of possible influence of the Simrad 

EM120 is much smaller--a narrow band 

oriented in the cross-track direction 

below the source vessel. Marine 

mammals that encounter the Simrad 

EM120 at close range are unlikely to be 

subjected to repeated pulses because of 

the narrow fore-aft width of the beam, 

and will receive only limited amounts 

of pulse energy because of the short 

pulses and vessel speed. Therefore, as 

harassment or injury from pulsed sound 

is a function of total energy received, 

the actual harassment or injury 

threshold for the bathymetric sonar 

signals would be at a much higher dB 

level than that for longer duration 

pulses such as seismic signals. As a 

result, NMFS believes that marine 

mammals are unlikely to be harassed or 

injured from the multibeam sonar. 

Masking by Mid-frequency Sonar 

Signals 

Marine mammal communications will 

not be masked appreciably by the 

multibeam sonar signals or the subbottom profiler given the low duty cycle 

and directionality of the sonars and the 

brief period when an individual 

mammal is likely to be within its beam. 

Furthermore, in the case of baleen 

whales, the sonar signals from the 

Simrad EM120 do not overlap with the 

predominant frequencies of their calls, 

which would avoid significant masking. 

For the sub-bottom profiler, marine 

mammal communications will not be 

masked appreciably because of their 

relatively low power output, low duty 

cycle, directionality (for the profiler), 

and the brief period when an individual 

mammal may be within the sonar’s 

beam. In the case of most odonotocetes, 

the sonar signals from the profiler do 

not overlap with the predominant 

frequencies in their calls. In the case of 

mysticetes, the pulses from the pinger 

do not overlap with their predominant 

frequencies. 

Behavioral Responses Resulting from 

Mid-Frequency Sonar Signals 

Behavioral reactions of free-ranging 

marine mammals to military and other 

sonars appear to vary by species and 

circumstance. Observed reactions have 

included silencing and dispersal by 

sperm whales (Watkins et al., 1985), 

increased vocalizations and no dispersal 

by pilot whales (Rendell and Gordon, 

1999), and the previously-mentioned 

strandings by beaked whales. Also, 

Navy personnel have described 

observations of dolphins bow-riding 

adjacent to bow-mounted mid-frequency 

sonars during sonar transmissions. 

However, all of these observations are of 

limited relevance to the present 

situation. Pulse durations from these 

sonars were much longer than those of 

the Scripps multibeam sonar, and a 

given mammal would have received 

many pulses from the naval sonars. 

During Scripps’ operations, the 

individual pulses will be very short, and 

a given mammal would not receive 

many of the downward-directed pulses 

as the vessel passes by. 

Captive bottlenose dolphins and a 

white whale exhibited changes in 

behavior when exposed to 1–sec pulsed 

sounds at frequencies similar to those 

that will be emitted by the multi-beam 

sonar used by Scripps and to shorter 

broadband pulsed signals. Behavioral 

changes typically involved what 

appeared to be deliberate attempts to 

avoid the sound exposure (Schlundt et 

al., 2000; Finneran et al., 2002). The 

relevance of these data to free-ranging 

odontocetes is uncertain and in any case 

the test sounds were quite different in 

either duration or bandwidth as 

compared to those from a bathymetric 

sonar. 

Scripps and NMFS are not aware of 

any data on the reactions of pinnipeds 

Federal Register / Vol. 70, No. 199 / Monday, October 17, 2005 / Notices 60295 

to sonar sounds at frequencies similar to 

those of the 12.0 kHz frequency of the 

Revelle’s multibeam sonar. Based on 

observed pinniped responses to other 

types of pulsed sounds, and the likely 

short duration of exposure to the 

bathymetric sonar sounds, pinniped 

reactions are expected to be limited to 

startle or otherwise brief responses of no 

lasting consequences to the individual 

animals. The pulsed signals from the 

sub-bottom profiler are much weaker 

than those from the multibeam sonar 

and somewhat weaker than those from 

the 2 GI-airgun array. Therefore, 

significant behavioral responses are not 

expected. 

Hearing Impairment and Other Physical 

Effects 

Given stranding events that have been 

associated with the operation of naval 

sonar, there is much concern that sonar 

noise can cause serious impacts to 

marine mammals (for discussion see 

Effects of Seismic Surveys on Marine 

Mammals). However, the multi-beam 

sonars proposed for use by Scripps are 

quite different than tactical sonars used 

for navy operations. Pulse duration of 

the bathymetric sonars is very short 

relative to the naval sonars. Also, at any 

given location, an individual marine 

mammal would be in the beam of the 

multi-beam sonar for much less time 

given the generally downward 

orientation of the beam and its narrow 

fore-aft beam-width. (Navy sonars often 

use near-horizontally directed sound.) 

These factors would all reduce the 

sound energy received from the multibeam sonar rather drastically relative to 

that from the sonars used by the Navy. 

Therefore, hearing impairment by multibeam bathymetric sonar is unlikely. 

Source levels of the sub-bottom 

profiler are much lower than those of 

the airguns and the multi-beam sonar. 

Sound levels from a sub-bottom profiler 

similar to the one on the Revelle were 

estimated to decrease to 180 dB re 1 

microPa (rms) at 8 m (26 ft) horizontally 

from the source (Burgess and Lawson, 

2000), and at approximately 18 m (59 ft) 

downward from the source. 

Furthermore, received levels of pulsed 

sounds that are necessary to cause 

temporary or especially permanent 

hearing impairment in marine mammals 

appear to be higher than 180 dB (see 

earlier discussion). Thus, it is unlikely 

that the sub-bottom profiler produces 

pulse levels strong enough to cause 

hearing impairment or other physical 

injuries even in an animal that is 

(briefly) in a position near the source. 

The sub-bottom profiler is usually 

operated simultaneously with other 

higher-power acoustic sources. Many 

marine mammals will move away in 

response to the approaching higherpower sources or the vessel itself before 

the mammals would be close enough for 

there to be any possibility of effects 

from the less intense sounds from the 

sub-bottom profiler. In the case of 

mammals that do not avoid the 

approaching vessel and its various 

sound sources, mitigation measures that 

would be applied to minimize effects of 

the higher-power sources would further 

reduce or eliminate any minor effects of 

the sub-bottom profiler. 

Estimates of Take by Harassment for 

the SWPO Seismic Survey 

Although information contained in 

this document indicates that injury to 

marine mammals from seismic sounds 

potentially occurs at sound pressure 

levels significantly higher than 180 and 

190 dB, NMFS’ current criteria for onset 

of Level A harassment of cetaceans and 

pinnipeds from impulse sound are, 

respectively, 180 and 190 re 1 microPa 

rms. The rms level of a seismic pulse is 

typically about 10 dB less than its peak 

level and about 16 dB less than its pkpk level (Greene, 1997; McCauley et al., 

1998; 2000a). The criterion for Level B 

harassment onset is 160 dB. 

Given the proposed mitigation (see 

Mitigation later in this document), all 

anticipated effects involve a temporary 

change in behavior that may constitute 

Level B harassment. The proposed 

mitigation measures will minimize or 

eliminate the possibility of Level A 

harassment or mortality. Scripps has 

calculated the ‘‘best estimates’’ for the 

numbers of animals that could be taken 

by level B harassment during the 

proposed SWPO seismic survey using 

data on marine mammal density 

(numbers per unit area) 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 2 GIgun array planned to be used for this 

project. The anticipated zones of 

influence of the multi-beam sonar and 

sub-bottom profiler are less than that for 

the airguns, so it is assumed that during 

simultaneous operations of these 

instruments that any marine mammals 

close enough to be affected by the multibeam and sub-bottom profiler sonars 

would already be affected by the 

airguns. Therefore, no additional 

incidental takings are included for 

animals that might be affected by the 

multi-beam sonar. Given their 

characteristics (described previously), 

no Level B harassment takings are 

considered likely when the multibeam 

and sub-bottom profiler are operating 

but the airguns are silent. 

Table 2 provides the best estimate of 

the numbers of each species that would 

be exposed to seismic sounds greater 

than 160 dB and the number of marine 

mammals requested to be taken by Level 

B harassment. A detailed description on 

the methodology used by Scripps to 

arrive at the estimates of Level B 

harassment takes that are provided in 

Table 2 can be found in Scripps’s IHA 

application for the SWPO survey. 

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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. Few 

mysticetes are expected to be 

encountered during the proposed survey 

in the ETPO (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 dolphins 

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 2 GI-gun array 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 cetaceans that may be 

exposed to sounds ≥160 dB re 1 microPa 

(rms) represent from 0 to approximately 

0.04 percent of the regional SWPO 

species populations (Table 2). In the 

case of endangered balaenopterids, it is 

most likely that no more than 1 

humpback, sei, or fin whale will be 

exposed to seismic sounds ≥160 dB re 

1 microPa (rms), based on estimated 

densities of those species in the survey 

region. Therefore, Scripps has requested 

an authorization to expose up to 1 

individuals of each of those species to 

seismic sounds of ≥160 dB during the 

proposed survey given the possibility of 

encountering one or more groups. Best 

estimates of blue whales are that no 

individuals would be potentially 

exposed to seismic pulses with received 

levels ≥160 dB re 1 microPa (rms)(Table 

2). 

Higher numbers of delphinids may be 

affected by the proposed seismic 

surveys, but the population sizes of 

species likely to occur in the survey area 

are large, and the numbers potentially 

affected are small relative to population 

sizes (Table 2). 

Mitigation measures such as 

controlled speed, course alteration, 

observers, ramp ups, 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 effects 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 

Five pinniped species may be 

encountered at the survey sites, but 

their distribution and numbers have not 

been documented in the proposed 

survey area. In all likelihood, these 

species will be in southern feeding areas 

during the period for this survey. 

However, to ensure that the Scripps 

project remains in compliance with the 

MMPA in the event that a few 

pinnipeds are encountered, Scripps has 

requested an authorization to expose up 

to 3–5 individuals of each of the five 

pinniped species to seismic sounds with 

rms levels ≥160 dB re 1 μPa. Therefore, 

the proposed survey would have, at 

most, a short-term effect on their 

behavior and no long-term impacts on 

individual pinnipeds or their 

populations. Responses of pinnipeds to 

acoustic disturbance are variable, but 

usually quite limited. Effects are 

expected to be limited to short-term and 

localized behavioral changes falling 

within the MMPA definition of Level B 

harassment. As is the case for cetaceans, 

the short-term exposures to sounds from 

the two GI-guns are not expected to 

result in any long-term consequences for 

the individuals or their populations and 

the activity is expected to have no more 

than a negligible impact on the affected 

species or stocks of pinnipeds. 

Potential Effects on Habitat 

The proposed seismic survey will not 

result in any permanent impact on 

habitats used by marine mammals, or to 

the food sources they utilize. The main 

impact issue associated with the 

proposed activity will be temporarily 

elevated noise levels and the associated 

direct effects on marine mammals. 

One of the reasons for the adoption of 

airguns as the standard energy source 

for marine seismic surveys was that they 

(unlike the explosives used in the 

distant past) do not result in any 

appreciable fish kill. Various 

experimental studies showed that 

airgun discharges cause little or no fish 

kill, and that any injurious effects were 

generally limited to the water within a 

meter or so of an airgun. However, it has 

recently been found that injurious 

effects on captive fish, especially on fish 

hearing, may occur at somewhat greater 

distances than previously thought 

(McCauley et al., 2000a,b, 2002; 2003). 

Even so, any injurious effects on fish 

would be limited to short distances from 

the source. Also, many of the fish that 

might otherwise be within the injuryzone are likely to be displaced from this 

region prior to the approach of the 

airguns through avoidance reactions to 

the approaching seismic vessel or to the 

airgun sounds as received at distances 

beyond the injury radius. 

Fish often react to sounds, especially 

strong and/or intermittent sounds of low 

frequency. Sound pulses at received 

levels of 160 dB re 1 μPa (peak) may 

cause subtle changes in behavior. Pulses 

at levels of 180 dB (peak) may cause 

noticeable changes in behavior 

(Chapman and Hawkins, 1969; Pearson 

et al., 1992; Skalski et al., 1992). It also 

appears that fish often habituate to 

repeated strong sounds rather rapidly, 

on time scales of minutes to an hour. 

However, the habituation does not 

endure, and resumption of the 

disturbing activity may again elicit 

disturbance responses from the same 

fish. 

Fish near the airguns are likely to dive 

or exhibit some other kind of behavioral 

response. This might have short-term 

impacts on the ability of cetaceans to 

feed near the survey area. However, 

only a small fraction of the available 

habitat would be ensonified at any given 

time, and fish species would return to 

their pre-disturbance behavior once the 

seismic activity ceased. Thus, the 

proposed surveys would have little 

impact on the abilities of marine 

mammals to feed in the area where 

seismic work is planned. Fish that do 

not avoid the approaching airguns 

(probably a small number) may be 

subject to auditory or other injuries. 

Zooplankton that are very close to the 

source may react to the airgun’s shock 

wave. These animals have an 

exoskeleton and no air sacs; therefore, 

Federal Register / Vol. 70, No. 199 / Monday, October 17, 2005 / Notices 60299 

little or no mortality is expected. Many 

crustaceans can make sounds and some 

crustacea and other invertebrates have 

some type of sound receptor. However, 

the reactions of zooplankton to sound 

are not known. Some mysticetes feed on 

concentrations of zooplankton. A 

reaction by zooplankton to a seismic 

impulse would only be relevant to 

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, so few 

zooplankton concentrations would be 

affected. Impacts on zooplankton 

behavior are predicted to be negligible, 

and this would translate into negligible 

impacts on feeding mysticetes. 

Potential Effects on Subsistence Use of 

Marine Mammals 

There is no known legal subsistence 

hunting for marine mammals in the 

SWPO, so the proposed Scripps 

activities will not have any impact on 

the availability of these species or stocks 

for subsistence users. 

Proposed Mitigation 

For the proposed seismic survey in 

the SWPO, Scripps will deploy 2 GIairguns as an energy source, each with 

a discharge volume of 45 in3. The 

energy from the airguns is directed 

mostly downward. The directional 

nature of the airguns to be used in this 

project is an important mitigating factor. 

This directionality will result in 

reduced sound levels at any given 

horizontal distance as compared with 

the levels expected at that distance if 

the source were omnidirectional with 

the stated nominal source level. Also, 

the small size of these airguns is an 

inherent and important mitigation 

measure that will reduce the potential 

for effects relative to those that might 

occur with large airgun arrays. This 

measure is in conformance with NMFS 

policy of encouraging seismic operators 

to use the lowest intensity airguns 

practical to accomplish research 

objectives. 

The following mitigation measures, as 

well as marine mammal visual 

monitoring (discussed later in this 

document), will be implemented for the 

subject seismic surveys: (1) Speed and 

course alteration (provided that they do 

not compromise operational safety 

requirements); (2) shut-down 

procedures; and (3) ramp-up 

procedures. 

Speed and Course Alteration 

If a marine mammal is detected 

outside its respective safety zone (180 

dB for cetaceans, 190 dB for pinnipeds) 

and, based on its position and the 

relative motion, is likely to enter the 

safety zone, the vessel’s speed and/or 

direct course may, when practical and 

safe, be changed to avoid the mammal 

in a manner that also minimizes the 

effect to the planned science objectives. 

The marine mammal activities and 

movements relative to the seismic vessel 

will be closely monitored to ensure that 

the marine mammal does not approach 

within the safety zone. If the mammal 

appears likely to enter the safety zone, 

further mitigative actions will be taken 

(i.e., either further course alterations or 

shut down of the airguns). 

Shut-down Procedures 

Although power-down procedures are 

often standard operating practice for 

seismic surveys, power-down is not 

proposed to be used for this activity 

because powering down from two guns 

to one gun would make only a small 

difference in the 180– or 190–dB 

radius—probably not enough to allow 

continued one-gun operations if a 

mammal came within the safety radius 

for two guns. 

If a marine mammal is detected 

outside the safety radius but is likely to 

enter the safety radius, and if the 

vessel’s speed and/or course cannot be 

changed to avoid having the mammal 

enter the safety radius, the GI-guns will 

be shut down before the mammal is 

within the safety radius. Likewise, if a 

mammal is already within the safety 

zone when first detected, the airguns 

will be shut down immediately. 

Following a shut down, airgun 

activity will not resume until the marine 

mammal has cleared the safety zone. 

The animal will be considered to have 

cleared the safety zone if it: (1) is 

visually observed to have left the safety 

zone, or (2) has not been seen within the 

zone for 15 min in the case of small 

odontocetes and pinnipeds, or (3) has 

not been seen within the zone for 30 

min in the case of mysticetes and large 

odontocetes, including sperm, pygmy 

sperm, dwarf sperm, beaked and 

bottlenose whales. 

During airgun operations following a 

shut-down whose duration has 

exceeded these specified limits, the 

airgun array will be ramped-up 

gradually. Ramp-up is described later in 

this document. 

Ramp-up Procedure 

A ramp-up procedure will be 

followed when the airguns begin 

operating after a period without airgun 

operations. The two GI guns will be 

added in sequence 5 minutes apart. 

During ramp-up procedures, the safety 

radius for the two GI guns will be 

maintained. 

During the day, ramp-up cannot begin 

from a shut-down unless the entire 180–

dB safety radius has been visible for at 

least 30 minutes prior to the ramp up 

(i.e., no ramp-up can begin in heavy fog 

or high sea states). 

During nighttime 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 airguns from a shut down may 

occur, after completion of the 30–

minute observation period. 

Comments on past IHAs raised the 

issue of prohibiting nighttime 

operations as a practical mitigation 

measure. However, this is not 

practicable due to cost considerations 

and ship time schedules. If the Revelle 

was prohibited from operating during 

nighttime, each trip could require an 

additional several days to complete. 

If a seismic survey vessel is limited to 

daylight seismic operations, efficiency 

would also be much reduced. Without 

commenting specifically on how that 

limitation 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 

Scripps must have at least three visual 

observers on board the Revelle, and at 

least two must be an experienced 

marine mammal observer that NMFS 

has approved in advance of the start of 

the SWPO cruise. These observers will 

be on duty in shifts of no longer than 

4 hours. 

The visual observers will monitor 

marine mammals and sea turtles near 

the seismic source vessel during all 

daytime airgun operations, during any 

nighttime start-ups of the airguns, 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 and sea turtles 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 

60300 Federal Register / Vol. 70, No. 199 / Monday, October 17, 2005 / Notices 

mammals near the source vessel are 

detected. Revelle 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. 

The observer(s) will systematically scan 

the area around the vessel with Big Eyes 

binoculars, reticle binoculars (e.g., 7 X 

50 Fujinon) and with the naked eye 

during the daytime. 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 or 

sea turtle 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-airguns are 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 airguns to be powered-down or 

shut-down if marine mammals 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 at any 

distance from the Revelle. If the 2 GIairgun is ramped-up at night (see 

previous section), two marine mammal 

observers will monitor for marine 

mammals for 30 minutes prior to rampup and during the ramp-up using either 

deck lighting or NVDs that will be 

available (ITT F500 Series Generation 3 

binocular image intensifier or 

equivalent). 

Post-Survey Monitoring 

In addition, the biological observers 

will be able to conduct monitoring of 

most recently-run transect lines as the 

Revelle returns along parallel and 

perpendicular transect tracks (see inset 

of Figure 1 in the Scripps application). 

This will provide the biological 

observers with opportunities to look for 

injured or dead marine mammals 

(although no injuries or mortalities are 

expected during this research cruise). 

Passive Acoustic Monitoring (PAM) 

Because of the very small zone for 

potential Level A harassment, Scripps 

has not proposed to use the PAM system 

during this cruise. 

Summary 

Taking into consideration the 

additional costs of prohibiting nighttime 

operations and the likely impact of the 

activity (including all mitigation and 

monitoring), NMFS has preliminarily 

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 operating 

seismic airguns, thereby giving them an 

opportunity to avoid the approaching 

array; if ramp-up is required, 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; rampup may not begin unless the entire 

safety radii are visible. 

Reporting 

Scripps will submit a report to NMFS 

within 90 days after the end of the 

cruise, which is currently predicted to 

occur during January and February, 

2006. 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) 

Under section 7 of the ESA, the 

National Science Foundation (NSF), the 

agency funding Scripps, has begun 

consultation on the proposed seismic 

survey. NMFS will also consult on the 

issuance of an IHA under section 

101(a)(5)(D) of the MMPA for this 

activity. Consultation will be concluded 

prior to a determination on the issuance 

of an IHA. 

National Environmental Policy Act 

(NEPA) 

The NSF has prepared an EA for the 

SWPO oceanographic surveys. NMFS is 

reviewing this EA and will either adopt 

it or prepare its own NEPA document 

before making a determination on the 

issuance of an IHA. A copy of the NSF 

EA for this activity is available upon 

request and is available online (see 

ADDRESSES). 

Preliminary Conclusions 

NMFS has preliminarily determined 

that the impact of conducting the 

seismic survey on the Louisville Ridge 

in the SWPO 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 preliminary 

determination is supported by: (1) the 

likelihood that, given advance notice 

through relatively slow ship speed and 

ramp-up, marine mammals are expected 

to move away from a noise source that 

is annoying before it becomes 

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 in the safety zone by trained 

observers is close to 100 percent during 

daytime and remains high at night to the 

short 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 would 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 

known 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. 

Proposed Authorization 

NMFS proposes to issue an IHA to 

Scripps for conducting an 

oceanographic seismic survey on the 

Louisville Ridge in the SWPO, provided 

the previously mentioned mitigation, 

monitoring, and reporting requirements 

are incorporated. NMFS has 

preliminarily determined that the 

proposed activity would result in the 

harassment of small numbers of marine 

Federal Register / Vol. 70, No. 199 / Monday, October 17, 2005 / Notices 60301 

mammals; would have no more than a 

negligible impact on the affected marine 

mammal stocks; and would not have an 

unmitigable adverse impact on the 

availability of species or stocks for 

subsistence uses. 

Information Solicited 

NMFS requests interested persons to 

submit comments and information 

concerning this request (see ADDRESSES). 

Dated: October 7, 2005 

James H. Lecky, 

Director, Office of Protected Resources, 

National Marine Fisheries Service. 

[FR Doc. 05–20712 Filed 10–14–05; 8:45 am] 

BILLING CODE 3510–22–S 

DEPARTMENT OF COMMERCE 

National Oceanic and Atmospheric 

Administration 

[I.D. 101105B] 

Fisheries of the South Atlantic; 

Research and Monitoring Workshop 

Supporting Ecosystem Management in 

the South Atlantic Region 

AGENCY: National Marine Fisheries 

Service (NMFS), National Oceanic and 

Atmospheric Administration (NOAA), 

Commerce. 

ACTION: Notice of Research and 

Monitoring Workshop Supporting 

Ecosystem Management in the South 

Atlantic Region. 

SUMMARY: The South Atlantic Fishery 

Management Council (Council) will 

conduct a research and monitoring 

workshop to support the Council’s 

evolution to ecosystem management in 

the South Atlantic region in Charleston, 

SC. 

DATES: The workshop will take place 

November 16–18, 2005. See 

SUPPLEMENTARY INFORMATION for specific 

dates and times. 

ADDRESSES: The workshop will be held 

at the Town and Country Inn and 

Conference Center, 2008 Savannah 

Highway, Charleston, SC 29407, 

telephone: (800) 334–6660 or (843) 571–

1000; fax: (843) 766–9444. 

FOR FURTHER INFORMATION CONTACT: Kim 

Iverson, Public Information Officer, 

South Atlantic Fishery Management 

Council, One Southpark Circle, Suite 

306, Charleston, SC 29407–4699; 

telephone: (843) 571–4366 or toll free 

(866) SAFMC–10; fax: (843) 769–4520; 

email: kim.iverson@safmc.net. 

SUPPLEMENTARY INFORMATION: Invited 

workshop participants will meet from 

8:30 a.m. – 5 p.m. on November 16–17, 

2005, and from 8:30 a.m. – 12:30 p.m. 

on November 18, 2005. The workshop is 

designed to identify priority research 

and monitoring needs by area of 

concern for inclusion into the Council’s 

Fishery Ecosystem Plan. Summary 

outputs from various break-out group 

sessions will provide a foundation from 

which the research and monitoring 

section of the Fishery Ecosystem Plan 

will be developed. They will also 

include recommendations supporting 

the expansion of research programs and 

enhancement of partnerships among 

federal and state agencies, universities, 

and institutions to support the move to 

ecosystem management. 

Although non-emergency issues not 

contained in this agenda may come 

before this group for discussion, those 

issues may not be the subject of formal 

action during these meetings. Action 

will be restricted to those issues 

specifically listed in this notice and any 

issues arising after publication of this 

notice that require emergency action 

under section 305(c) of the MagnusonStevens Act, provided the public has 

been notified of the Council’s intent to 

take final action to address the 

emergency. 

Note: The times and sequence 

specified in this agenda are subject to 

change. 

Special Accommodations 

These meetings are physically 

accessible to people with disabilities. 

Requests for auxiliary aids should be 

directed to the Council office (see 

ADDRESSES) 3 days prior to the meetings. 

Dated: October 12, 2005. 

Emily Menashes, 

Acting Director, Office of Sustainable 

Fisheries, National Marine Fisheries Service. 

[FR Doc. E5–5708 Filed 10–14–05; 8:45 am] 

BILLING CODE 3510–22–S 

DEPARTMENT OF COMMERCE 

National Oceanic and Atmospheric 

Administration 

[I.D. 101205A] 

General Advisory Committee to the 

U.S. Section to the Inter-American 

Tropical Tuna Commission (IATTC); 

Meeting Announcement 

AGENCY: National Marine Fisheries 

Service (NMFS), National Oceanic and 

Atmospheric Administration (NOAA), 

Commerce. 

ACTION: Notice of public meeting. 

SUMMARY: NMFS announces the meeting 

of the General Advisory Committee to 

the U.S. Section to the IATTC on 

November 1, 2005. 

DATES: The open session of the General 

Advisory Committee meeting will be 

held on November 1, 2005, from 10 to 

5 pm. 

ADDRESSES: The meeting will be held at 

NMFS, Southwest Fisheries Science 

Center, Large Conference Room, 8604 La 

Jolla Shores Drive, La Jolla, CA 92037–

1508. 

FOR FURTHER INFORMATION CONTACT: J. 

Allison Routt at (562)980–4019. 

SUPPLEMENTARY INFORMATION: In 

accordance with the Tuna Conventions 

Act, as amended, the Department of 

State has appointed a General Advisory 

Committee to the U.S. Section to the 

IATTC. The U.S. Section consists of the 

four U.S. Commissioners to the IATTC 

and the representative of the Deputy 

Assistant Secretary of State for Oceans 

and Fisheries. The Advisory Committee 

supports the work of the U.S. Section 

ina solely advisory capacity with 

respect to U.S. participation in the work 

of the IATTC, with particular reference 

to the development of policies and 

negotiating positions pursued at 

meetings of the IATTC. NMFS, 

Southwest Region, administers the 

Advisory Committee in cooperation 

with the Department of State. 

The General Advisory Committee to 

the U.S. Section to the IATTC will meet 

to receive and discuss information on: 

(1) the results of the June 2005 Annual 

Meeting of the IATTC, (2) 2005 IATTC 

activities, (3) recent and upcoming 

meetings of the IATTC and its working 

groups, (4) IATTC cooperation with 

other regional fishery management 

organizations, and (5) Advisory 

Committee operational issues. The 

public will have access to the open 

session of the meeting. 

Special Accommodations 

The meeting location is physically 

accessible to people with disabilities. 

Requests for sign language 

interpretation or other auxiliary aids 

should be directed to Allison Routt at 

(562) 980–4019 at least 10 days prior to 

the meeting date. 

Dated: October 12, 2005. 

Alan D. Risenhoover, 

Acting Director, Office of Sustainable 

Fisheries, National Marine Fisheries Service. 

[FR Doc. 05–20714 Filed 10–14–05; 8:45 am] 

BILLING CODE 3510–22–S