Federal Register / Vol. 74, No. 99 / Tuesday, May 26, 2009 / Notices 24799 

such other appropriate matters as the 

Under Secretary refers to the Panel for 

review and advice. 

DATES: Re ́sume ́s should be sent to the 

address, e-mail, or fax specified and 

must be received by June 26, 2009. 

ADDRESSES: Director, Office of Coast 

Survey, National Ocean Service, NOAA 

(N/CS), 1315 East West Highway, Silver 

Spring, MD 20910, fax: 301–713–4019, 

e-mail: Hydroservices.panel@noaa.gov. 

FOR FURTHER INFORMATION CONTACT: 

Captain Steven Barnum, NOAA, 

Director, Office of Coast Survey, 

National Ocean Service (NOS), NOAA 

(N/CS), 1315 East West Highway, Silver 

Spring, Maryland 20910; Telephone: 

301–713–2770, Fax: 301–713–4019; 

e-mail: steven.barnum@noaa.gov. 

SUPPLEMENTARY INFORMATION: Under 33 

U.S.C. 883a, et seq., NOAA’s National 

Ocean Service (NOS) is responsible for 

providing nautical charts and related 

information for safe navigation. NOS 

collects and compiles hydrographic, 

tidal and current, geodetic, and a variety 

of other data in order to fulfill this 

responsibility. The Hydrographic 

Services Review Panel provides advice 

on topics such as ‘‘NOAA’s 

Hydrographic Survey Priorities,’’ 

technologies relating to operations, 

research and development of data 

pertaining to: 

(a) Hydrographic surveying; 

(b) Nautical charting; 

(c) Water level measurements; 

(d) Current measurements; 

(e) Geodetic measurements; and 

(f) Geospatial measurements. 

The Panel comprises fifteen voting 

members appointed by the Under 

Secretary in accordance with section 

105 of Public Law 107–372. Members 

are selected on a standardized basis, in 

accordance with applicable Department 

of Commerce guidance. The Co-Director 

of the Joint Hydrographic Center and 

two other employees of the National 

Oceanic and Atmospheric 

Administration serve as nonvoting 

members of the Panel. The Director, 

Office of Coast Survey, serves as the 

Designated Federal Official (DFO). This 

solicitation is to obtain candidate 

applications for one current voting 

vacancy on the Panel, and for five 

voting members whose terms expire 

January 1, 2010, and candidates for 

voting members who might resign at any 

time during 2009. Be advised that some 

voting members whose terms expire 

January 1, 2010, may be reappointed for 

another full term if eligible. 

Voting members are individuals who, 

by reason of knowledge, experience, or 

training, are especially qualified in one 

or more disciplines relating to 

hydrographic surveying, tides, currents, 

geodetic and geospatial measurements, 

marine transportation, port 

administration, vessel pilotage, and 

coastal or fishery management. An 

individual may not be appointed as a 

voting member of the Panel if the 

individual is a full-time officer or 

employee of the United States. Any 

voting member of the Panel who is an 

applicant for, or beneficiary of (as 

determined by the Under Secretary) any 

assistance under the Act shall disclose 

to the Panel that relationship, and may 

not vote on any other matter pertaining 

to that assistance. 

Voting members of the Panel serve a 

four-year term, except that vacancy 

appointments shall be for the remainder 

of the unexpired term of the vacancy. 

Members serve at the discretion of the 

Under Secretary and are subject to 

government ethics standards. Any 

individual appointed to a partial or full 

term may be reappointed for one 

additional full term. A voting member 

may serve until his or her successor has 

taken office. The Panel selects one 

voting member to serve as the Chair and 

another to serve as the Vice Chair. The 

Vice Chair acts as Chair in the absence 

or incapacity of the Chair but will not 

automatically become the Chair if the 

Chair resigns. Meetings occur at least 

twice a year, and at the call of the Chair 

or upon the request of a majority of the 

voting members or of the Under 

Secretary. Voting members receive 

compensation at a rate established by 

the Under Secretary, not to exceed the 

maximum daily rate payable under 

section 5376 of title 5, United States 

Code, when engaged in performing 

duties for the Panel. Members are 

reimbursed for actual and reasonable 

expenses incurred in performing such 

duties. 

Panel members selected to serve on 

the HSRP FACA committee must 

complete the following: 

(a) Security Clearance (on-line 

Background Security Check process and 

fingerprinting conducted through 

NOAA Workforce Management); 

(b) Confidential Financial Disclosure 

Report—As an SGE you are required to 

file a Confidential Financial Disclosure 

Report to avoid involvement in a real or 

apparent conflict of interest. You may 

find the Confidential Financial 

Disclosure Report at the following Web 

site: http://www.usoge.gov/forms/ 

form_450.aspx. 

(c) Certification of Status Statement 

(certifying statement that as an SGE you 

are not an agent of a foreign principal 

or a lobbyist—document provided by 

NOAA). 

Dated: May 19, 2009. 

Captain Steven Barnum, 

NOAA, Director, Office of Coast Survey, 

National Ocean Service, National Oceanic 

and Atmospheric Administration. 

[FR Doc. E9–12066 Filed 5–22–09; 8:45 am] 

BILLING CODE P 

DEPARTMENT OF COMMERCE 

National Oceanic and Atmospheric 

Administration 

RIN 0648–XO71 

Incidental Takes of Marine Mammals 

During Specified Activities; LowEnergy Marine Seismic Survey in the 

Northeast Pacific Ocean, July 2009 

AGENCY: National Marine Fisheries 

Service (NMFS), National Oceanic and 

Atmospheric Administration (NOAA), 

Commerce. 

ACTION: Notice; proposed incidental 

take authorization; request for 

comments. 

SUMMARY: NMFS has received an 

application from the Scripps Institution 

of Oceanography (SIO), a part of the 

University of California San Diego 

(UCSD), for an Incidental Harassment 

Authorization (IHA) to take small 

numbers of marine mammals, by 

harassment, incidental to conducting a 

marine seismic survey in the Northeast 

Pacific Ocean during July 2009. 

Pursuant to the Marine Mammal 

Protection Act (MMPA), NMFS requests 

comments on its proposal to authorize 

SIO to incidentally take, by Level B 

harassment only, small numbers of 

marine mammals during the 

aforementioned activity. 

DATES: Comments and information must 

be received no later than June 25, 2009. 

ADDRESSES: Comments on the 

application should be addressed to 

Michael Payne, Chief, Permits, 

Conservation and Education Division, 

Office of Protected Resources, National 

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

20910–3225. The mailbox address for 

providing email comments is PR1.0648– 

XO71@noaa.gov. Comments sent via email, 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 may be obtained by writing to 

the address specified above, telephoning 

the contact listed below (see FOR

FURTHER INFORMATION CONTACT), or 

visiting the internet at: http:// 

www.nmfs.noaa.gov/pr/permits/ 

incidental.htm. 

24800 Federal Register / Vol. 74, No. 99 / Tuesday, May 26, 2009 / Notices 

Documents cited in this notice may be 

viewed, by appointment, during regular 

business hours, at the aforementioned 

address. 

FOR FURTHER INFORMATION CONTACT: 

Howard Goldstein or Ken Hollingshead, 

Office of Protected Resources, NMFS, 

301–713–2289. 

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 United States 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. 

Authorization for incidental taking 

shall be granted if NMFS finds that the 

taking will have a negligible impact on 

the species or stock(s), will not have an 

unmitigable adverse impact on the 

availability of the species or stock(s) for 

subsistence uses, and if the permissible 

methods of taking and requirements 

pertaining to the mitigation, monitoring 

and reporting of such 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 

[ALevel 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 

[ALevel 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 small numbers 

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 March 9, 2009, NMFS received an 

application from SIO for the taking, by 

Level B harassment only, of small 

numbers of marine mammals incidental 

to conducting, under cooperative 

agreement with the National Science 

Foundation (NSF), a low-energy marine 

seismic survey in the Northeast Pacific 

Ocean. The funding for the survey is 

provided by the NSF. The proposed 

survey will occur in an overall area 

between approximately 44° and 45° N. 

and 124.5° and 126° W. within the 

Exclusive Economic Zone (EEZ) of the 

U.S.A., and is scheduled to occur from 

July 14–20, 2009. The survey will use a 

single Generator Injector (GI) airgun 

with a discharge volume of 45 in3. Some 

minor deviation from these dates is 

possible, depending on logistics and 

weather. 

The proposed survey is virtually 

identical to one conducted by SIO in 

2007 under an IHA issued in September 

2007 (NMFS 2007). The proposed SIO 

2009 IHA application contains minor 

updates to the project description, 

updated marine mammal population 

sizes based on the most recent NMFS 

annual stock assessment, an assessment 

of the relevance of the marine mammal 

density and distribution data contained 

in the SIO 2007 IHA application based 

on cruise reports from the NMFS 

SWFSC ORCAWHALE 2008 cruise, and 

updated information on effects of 

airguns on marine mammals (see 

Appendix A of SIO’s application). 

Description of the Specified Activity 

SIO plans to conduct an ocean bottom 

seismograph (OBS) deployment and a 

magnetic, bathymetric, and seismic 

survey. The planned survey will involve 

one source vessel, the R/V Wecoma 

(Wecoma), and will occur in the 

Northeast Pacific Ocean off the coast of 

Oregon. 

The purpose of the research program 

is to record micro-earthquakes in the 

forearc to determine whether seismicity 

on the plate boundary is characteristic 

of a locked or a freely slipping fault 

plane. Several earthquakes large enough 

to be recorded on land-based seismic 

nets have occurred along this segment 

in the past several years. The occurrence 

of ‘‘repeating earthquakes’’ (earthquakes 

with identical waveforms indicating 

repeated rupture of almost the same 

fault patch) suggests that this region is 

at a boundary between a freely slipping 

and a locked portion of the fault. Some 

models suggest that the forearc basin 

north of the seismically active zone may 

be locked; others suggest that portion of 

the fault is slipping freely. OBSs have 

been deployed for a year, and a seismic 

survey will be used to characterize the 

shallow sediment structure around the 

instruments. Also, included in the 

research is the use of a magnetometer 

and sub-bottom profiler. 

The source vessel, the Wecoma, will 

deploy a single low-energy GI airgun as 

an energy source (with a discharge 

volume of 45 in3) and a 300 m (984 ft), 

16 channel, towed hydrophone 

streamer. Sixteen OBSs were deployed 

in July and September 2008. They will 

continue to acquire data during this 

cruise, and will be recovered before 

returning to port. The energy to the GI 

airgun is compressed air supplied by 

compressors onboard the source vessel. 

As the GI airgun is towed along the 

survey lines, the receiving systems will 

receive the returning acoustic signals. 

The seismic program will consist of 

approximately 21 km (13 mi) of surveys 

over each of the 16 OBSs (see Figure 1 

of SIO’s application). Water depths at 

the seismic survey locations rang from 

just less than 100 m (328 ft) to almost 

3,000 m (9,842 ft) (see Figure 1 of SIO’s 

application). The GI airgun will be 

operated on a small grid for 

approximately two hours at each of the 

16 OBS sites. There will be additional 

seismic operations associated with 

equipment testing, start-ups, and repeat 

coverage of any areas where initial data 

quality is substandard. 

All planned geophysical data 

acquisition activities will be conducted 

by SIO with on-board assistance by the 

scientists who have proposed the study. 

The Chief Scientist is Dr. Anne Trehu of 

Oregon State University. The vessel will 

be self-contained, and the crew will live 

aboard the vessel for the entire cruise. 

In addition to the seismic operations 

of the single GI airgun, a 3.5 and 12 kHz 

sub-bottom profiler will be used 

continuously throughout the cruise, and 

a magnetometer may be run on the 

transit between OBS locations. 

Vessel Specifications 

The Wecoma has a length of 56.4 m 

(185 ft), a beam of 10.1 m (33.1 ft), and 

a maximum draft of 5.6 m (18.4 ft). The 

ship is powered by a single 3,000–hp 

EMD diesel engine driving a single, 

controllable-pitch propeller through a 

clutch and reduction gear, and an 

electric 350–hp azimuthing bow 

thruster. An operations speed of 11.1 

km/hour (6 knots) will be used during 

seismic acquisition. When not towing 

seismic survey gear, the Wecoma cruises 

at 22.2 km/hour (12 knots) and has a 

maximum speed of 26 km/hour (14 

Federal Register / Vol. 74, No. 99 / Tuesday, May 26, 2009 / Notices 24801 

knots). It has a normal operating range 

of approximately 13,300 km. The 

Wecoma will also serve as the platform 

from which vessel-based Marine 

Mammal Visual Observers (MMVO) will 

watch for animals before and during GI 

airgun operations. 

Acoustic Source Specifications 

Seismic Airguns 

During the proposed survey, the 

Wecoma will tow a single GI airgun, 

with a volume of 45 in3, and a 300 m 

long streamer containing hydrophones 

along predetermined lines. Seismic 

pulses will be emitted at intervals of 10 

seconds. At a speed of 6 knots (11.1 km/ 

hour), the 10 second shot spacing 

corresponds to a shot interval of 

approximately 31 m (101.7 ft). 

The generator chamber of the GI 

airgun, the one responsible for 

introducing the sound pulse into the 

ocean, is 45 in3. The larger (105 in3) 

injector chamber injects air into the 

previously-generated bubble to maintain 

its shape, and does not introduce more 

sound into the water. The 45 in3 GI 

airgun will be towed 21 m (68.9 ft) 

behind the Wecoma at a depth of 4 m 

(13.1ft). The sound pressure field of that 

GI airgun variation at a tow depth of 2.5 

m has been modeled by Lamont-Doherty 

Earth Observatory (L-DEO) in relation to 

distance and direction for the GI airgun. 

As the GI airgun is towed along the 

survey line, the towed hydrophone 

array in the 300 m streamer receives the 

reflected signals and transfers the data 

on the on-board processing system. 

Given the relatively short streamer 

length behind the vessel, the turning 

rate of the vessel while the gear is 

deployed is much higher than the limit 

of five degrees per minute for a seismic 

vessel towing a streamer of more typical 

length (much greater than 1 km). Thus, 

the maneuverability of the vessel is not 

limited much during operations. 

The root mean square (rms) received 

levels that are used as impact criteria for 

marine mammals are not directly 

comparable to the peak (pk or 0–pk) or 

peak-to-peak (pk - pk) values normally 

used to characterize source levels of 

airgun arrays. The measurement units 

used to describe airgun sources, peak or 

peak-to-peak decibels, are always higher 

than the ‘‘root mean square’’ (rms) 

decibels referred to in biological 

literature. A measured received level of 

160 dB re 1 μPa (rms) in the far field 

would typically correspond to a peak 

measurement of approximately 170 to 

172 dB, and to a peak-to-peak 

measurement of approximately 176 to 

178 dB, 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 peak-to-peak 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 peak-to-peak level for 

an airgun-type source. 

Received sound levels have been 

modeled by L-DEO for a number of 

airgun configurations, including one 45 

in3 GI airgun, in relation to distance 

from the airgun(s) (see Figure 2 of SIO’s 

application). The model does not allow 

for bottom interactions, and is most 

directly applicable to deep water. Based 

on modeling, estimates of the maximum 

distances from the GI airgun where 

sound levels of 190, 180, and 160 dB re 

1 μPa (rms) are predicted to be received 

in deep (≤1,000 m) water are shown in 

Table 1 of SIO’s application. Because 

the model results are for a 2.5 m tow 

depth, the distances in Table 1 slightly 

underestimate the distances for the 45 

in3 GI airgun towed at 4 m depth. 

Sub-bottom Profiler 

Along with the GI airgun operations, 

one additional acoustical data 

acquisition system will be operated 

throughout the cruise. The ocean floor 

will be mapped with a Knudsen 

Engineering Model 320BR 12 kHz and 

3.5 kHz sub-bottom profiler (SBP). 

Multi-beam sonar will not be used. 

The Knudsen Engineering Model 

320BR SBP is a dual-frequency 

transceiver designed to operate at 3.5 

and/or 12 kHz. It is used to provide data 

about the sedimentary features that 

occur below the sea floor. The energy 

from the sub-bottom profiler is directed 

downward via a 12 kHz transducer 

(EDO 323B) or a 3.5 kHz array of 16 ORE 

137D transducers in a 4x4 arrangement. 

The maximum power output of the 

320BR is 10 kilowatts for the 3.5 kHz 

section and 2 kilowatts for the 12 kHz 

section. 

The pulse length for the 3.5 kHz 

section of the 320 BR is 0.8–24 ms, 

controlled by the system operator in 

regards to water depth and reflectivity 

of the bottom sediments, and will 

usually be 12 or 24 ms in this survey. 

The system produces one sound pulse 

and then waits for its return before 

transmitting again. Thus, the pulse 

interval is directly dependent upon 

water depth, and in this survey is 4.5– 

8 seconds. Using the Sonar Equations 

and assuming 100 percent efficiency in 

the system (impractical in real world 

applications), the source level for the 

320BR is calculated to be 211 dB re 1 

Pam. In practical operation, the 3.5 kHz 

array is seldom driven at more than 80 

percent of maximum, usually less than 

50 percent. 

Safety Radii 

NMFS has determined that for 

acoustic effects, using acoustic 

thresholds in combination with 

corresponding safety radii is an effective 

way to consistently apply measures to 

avoid or minimize the impacts of an 

action, and to quantitatively estimate 

the effects of an action. Thresholds are 

used in two ways: (1) to establish a 

mitigation shut-down or power-down 

zone, i.e., if an animal enters an area 

calculated to be ensonified above the 

level of an established threshold, a 

sound source is powered down or shut 

down; and (2) to calculate take, in that 

a model may be used to calculate the 

area around the sound source that will 

be ensonified to that level or above, 

then, based on the estimated density of 

animals and the distance that the sound 

source moves, NMFS can estimate the 

number of marine mammals that may be 

‘‘taken.’’ 

As a matter of past practice and based 

on the best available information at the 

time regarding the effects of marine 

sound compiled over the past decade, 

NMFS has used conservative numerical 

estimates to approximate where Level A 

harassment from acoustic sources 

begins: 180 dB re 1 μPa (rms) level for 

cetaceans and 190 dB re 1 μPa (rms) for 

pinnipeds. A review of the available 

scientific data using an application of 

science-based extrapolation procedures 

(Southall et al., 2007) strongly suggests 

that Level A harassment (as well as 

TTS) from single sound exposure 

impulse events may occur at much 

higher levels than the levels previously 

estimated using very limited data. 

However, for purposes of this proposed 

action, SIO’s application sets forth, and 

NMFS is using, the more conservative 

180 and 190 dB re 1 μPa (rms) criteria. 

NMFS also considers 160 dB re 1 μPa 

(rms) as the criterion for estimating the 

onset of Level B harassment from 

acoustic sources like impulse sounds 

used in the seismic survey. 

Emperical data concerning the 180 

and 160 dB distances have been 

acquired based on measurements during 

the acoustic verification study 

conducted by L-DEO in the northern 

Gulf of Mexico from May 27 to June 3, 

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

results are limited the data showed that 

radii around the airguns where the 

received level would be 180 dB re 1 μPa 

(rms), the safety criterion applicable to 

cetaceans (NMFS, 2000), vary with 

water depth. Similar depth-related 

variation is likely in the 190 dB 

distances applicable to pinnipeds. 

24802 Federal Register / Vol. 74, No. 99 / Tuesday, May 26, 2009 / Notices 

Correction factors were developed for 

water depths 100–1,000 m and <100 m. 

The empirical data indicate that, for 

deep water (>1,000 m), the L-DEO 

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 GI 

airgun operations in deep water will be 

values predicted by L-DEO’s model (see 

Table 1 below). Therefore, the assumed 

180 and 190 dB radii are 23 m (75.5 ft) 

and 8 m (26 ft) respectively. 

Empirical measurements indicated 

that in shallow water (<100 m), the LDEO model under estimates actual 

levels. In previous L-DEO projects, the 

exclusion zones were typically based on 

measured values and ranged from 1.3 to 

15x higher than the modeled values 

depending on the size of the airgun 

array and the sound level measured 

(Tolstoy et al., 2004). During the 

proposed cruise, similar factors will be 

applied to derive appropriate shallow 

water radii from the modeled deep 

water radii for the GI airgun (see Table 

1 below). 

Empirical measurements were not 

conducted for intermediate depths 

(100–1,000 m). On the expectation that 

results will be intermediate between 

those from shallow and deep water, a 

1.5x correction factor is applied to the 

estimates provided by the model for 

deep water situations. This is the same 

factor that was applied to the model 

estimates during L-DEO cruises in 2003. 

The assumed 180 and 190 dB radii in 

intermediate depth water are 35 m (115 

ft) and 12 m (39.4 ft), respectively (see 

Table 1 below). 

TABLE 1. PREDICTED DISTANCES TO WHICH SOUND LEVELS ≥190, 180, AND 160 DB RE 1 μPA MIGHT BE RECEIVED IN

SHALLOW (<100 M; 328 FT), INTERMEDIATE (100–1,000 M; 328–3,280 FT), AND DEEP (>1,000 M; 3,280 FT) WATER

FROM THE SINGLE 45 IN3 GI AIRGUN USED DURING THE SEISMIC SURVEYS IN THE NORTHEASTERN PACIFIC OCEAN

DURING JULY 2009. DISTANCES ARE BASED ON MODEL RESULTS PROVIDED BY L-DEO. 

Source and Volume Tow Depth (m) Water Depth 

Predicted RMS Distances (m) 

190 dB 180 dB 160 dB 

Single GI airgun 45 in3 4 Deep (>1,000 m) 8 23 220 

Intermediate (100– 

1,000 m) 

12 35 330 

Shallow (< 100 m) 95 150 570 

Proposed Dates, Duration, and Region 

of Activity 

The Wecoma is scheduled to depart 

from Newport, Oregon, on July 14, 2009 

and to return on July 20, 2009. The GI 

airgun will be used for approximately 

two hours at each of 16 OBS locations. 

The program will consist of 

approximately 7 days of seismic 

acquisition. The exact dates of the 

activities may vary by a few days 

because of weather conditions, 

repositioning, streamer operations, and 

adjustments, GI airgun deployment, or 

the need to repeat some lines if data 

quality is substandard. The seismic 

surveys will take place off the Oregon 

coast in the northeastern Pacific Ocean 

(see Figure 1 of SIO’s application). The 

overall area within which the seismic 

surveys will occur is located between 

approximately 44° and 45° N and 124.5° 

and 126° W (see Figure 1 of SIO’s 

application). The surveys will take place 

in water depths just less than 100 m and 

to almost 3,000 m, entirely within the 

Exclusive Economic Zone (EEZ) of the 

U.S.A. 

Description of Marine Mammals in the 

Proposed Activity Area 

A total of 32 marine mammal species 

may occur or have been documented to 

occur in the marine waters off Oregon 

and Washington, excluding extralimital 

sightings or strandings (Fiscus and 

Niggol, 1965; Green et al., 1992, 1993; 

Barlow, 1997, 2003; Mangels and 

Gerrodette, 1994; Von Saunder and 

Barlow, 1999; Barlow and Taylor, 2001; 

Buchanan et al., 2001; Calambokidis et 

al., 2004; Calambokidis and Barlow, 

2004). The species include 19 

odontocetes (toothed cetaceans, such as 

dolphins), 7 mysticetes (baleen whales), 

5 pinnipeds, and sea otters. Six of the 

species that may occur in the project 

area are listed under the Endangered 

Species Act (ESA) as Endangered, 

including sperm, humpback, sei, fin, 

blue, and North Pacific right whales. 

Another species, the Steller sea lion, is 

listed as Threatened and may occur in 

the project area. 

The study area is located 

approximately 25 to 110 km (15.5 to 

68.4 mi) offshore from Oregon over 

water depths from just less than 100 m 

to almost 3,000 m. Two of the 32 

species, gray whales and sea otters, are 

not expected in the project area because 

their occurrence off Oregon is limited to 

very shallow, coastal waters. Three 

other species, California sea lions, 

Steller sea lions, and harbor seals, are 

mainly coastal, and would be rare at 

most at the OBS locations. Information 

on the habitat, abundance, and 

conservation status of the species that 

may occur in the study area are given 

in Table 2 (below, see Table 2 of SIO’s 

application). Vagrant ringed seals, 

hooded seals, and ribbon seals have 

been sighted or stranded on the coast of 

California (see Mead, 1981; Reeves et 

al., 2002) and presumably passed 

through Oregon waters. A vagrant 

beluga whale was seen off the coast of 

Washington (Reeves et al., 2002). Those 

seven species are not addressed in detail 

in the summaries in SIO’s application. 

The six species of marine mammals 

expected to be most common in the 

deep pelagic or slope waters of the 

project area, where most of the survey 

sites are located, include the Pacific 

white-sided dolphin, northern right 

whale dolphin, Risso’s dolphin, short 

beaked common dolphin, Dall’s 

porpoise, and northern fur seal (Green et 

al., 1992, 1993; Buchanan et al., 2001; 

Barlow, 2003; Barlow and Forney, 2007; 

Carretta et al., 2007). The fin whale, 

Dall’s porpoise, and the northern 

elephant seal were the species sighted 

most often off Oregon and Washington 

during the ORCAWALE 2008 surveys 

(NMFS, 2008). 

Table 2 below outlines the marine 

mammal species, their habitat, 

abundance, density, and conservation 

status in the proposed project area. 

Additional information regarding the 

distribution of these species expected to 

be found in the project area and how the 

estimated densities were calculated may 

be found in SIO’s application. 

BILLING CODE 3510–22–S 

Federal Register / Vol. 74, No. 99 / Tuesday, May 26, 2009 / Notices 24803 


EN26MY09.019</GPH>
24804 Federal Register / Vol. 74, No. 99 / Tuesday, May 26, 2009 / Notices 


EN26MY09.020</GPH>
Federal Register / Vol. 74, No. 99 / Tuesday, May 26, 2009 / Notices 24805 

BILLING CODE 3510–22–C 

Potential Effects on Marine Mammals 

Potential Effects of Airguns 

The effects of sounds from airguns 

might result in one or more of the 

following: tolerance, masking of natural 

sounds, behavioral disturbances, 

temporary or permanent hearing 

impairment, and non-auditory physical 

or physiological effects (Richardson et 

al., 1995; Gordon et al., 2004; Nowacek 

et al., 2007; Southall et al., 2007). 

Permanent hearing impairment, in the 

unlikely event that it occurred, would 

constitute injury, but temporary 

threshold shift (TTS) is not an injury 

(Southall et al., 2007). With the possible 

exception of some cases of temporary 

threshold shift in harbor seals, it is 

unlikely that the project would result in 

any cases of temporary or especially 

permanent hearing impairment, or any 

significant non-auditory physical or 

physiological effects. 

Tolerance 

Numerous studies have shown that 

pulsed sounds from airguns are often 

readily detectable in the water at 

distances of many kilometers. For a brief 

summary of the characteristics of airgun 

pulses, see Appendix A(3) of SIO’s 

application. However, it should be 

noted that most of the measurements are 

for airguns that would be detectable 

considerably farther away than the GI 

airgun planned for use in the present 

project. 

Several studies have shown that 

marine mammals at distances more than 

a few kilometers from operating seismic 

vessels often show no apparent 

response-see Appendix A(5) of SIO’s 

application. 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 the mammal 

group. Although various baleen whales, 

toothed whales, and (less frequently) 

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 

usually seem to be more tolerant of 

exposure to airgun pulses than are 

cetaceans, with relative responsiveness 

of baleen and toothed whales being 

variable. Given the relatively small and 

low-energy GI airgun source planned for 

use in this project, mammals are 

expected to be tolerate being closer to 

this source than would be the case for 

a larger airgun source typical of most 

seismic surveys. 

Masking 

Obscuring of sounds of interest by 

interfering sounds, generally at similar 

frequencies, is known as 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, although 

there are few specific data of relevance. 

Because of the intermittent nature and 

low duty cycle of seismic pulses, 

animals can emit and receive sounds in 

the relatively quiet intervals between 

pulses. However in some situations, 

multi-path arrivals and reverberation 

cause airgun sound to arrive for much 

or all of the interval between pulses 

(Simard et al., 2005; Clark and Gagnon, 

2006), which could mask calls. Some 

baleen and toothed whales are known to 

continue calling in the presence of 

seismic pulses. The airgun sounds are 

pulsed, with quiet periods between the 

pulses, and whale calls often can be 

heard between the seismic pulses 

(Richardson et al., 1986; McDonald et 

al., 1995; Greene et al., 1999; Nieukirk 

et al., 2004; Smultea et al., 2004; Holst 

et al., 2005a,b, 2006). In the northeast 

Pacific Ocean, blue whale calls have 

been recorded during a seismic survey 

off Oregon (McDonald et al., 1995). 

Among odontocetes, there has been one 

report that sperm whales cease calling 

when exposed to pulses from a very 

distant seismic ship (Bowles et al., 

1994). However, more recent studies 

found that sperm whales continued 

calling in the presence of seismic pulses 

(Madsen et al., 2002; Tyack et al., 2003; 

Smultea et al., 2004; Holst et al., 2006; 

Jochens et al., 2006, 2008). Given the 

small source planned for use during the 

proposed survey, there is even less 

potential for masking of baleen or 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 small 

odontocetes given the intermittent 

nature of seismic pulses. Dolphins and 

porpoises commonly are heard calling 

while airguns are operating (Gordon et 

al., 2004; Smultea et al., 2004; Holst et 

al., 2005a,b; Potter et al., 2007). Also, 

the sounds important to small 

odontocetes are predominantly at much 

higher frequencies than the airgun 

sounds, thus further limiting the 

potential for masking. In general, 

masking effects of seismic pulses are 

expected to be minor, given the 

normally intermittent nature of seismic 

pulses. Masking effects on marine 

mammals are discussed further in 

Appendix A (4) of SIO’s application. 

Disturbance Reactions 

Disturbance includes a variety of 

effects, including subtle changes in 

behavior, more conspicuous changes in 

activities, and displacement. 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 responds to an underwater 

sound by changing its behavior or 

moving a small distance, the response 

may or may not rise to the level of 

‘‘harassment,’’ or affect the stock or the 

species as a whole. However, if a sound 


EN26MY09.021</GPH>
24806 Federal Register / Vol. 74, No. 99 / Tuesday, May 26, 2009 / Notices 

source displaces marine mammals from 

an important feeding or breeding area 

for a prolonged period, impacts on 

animals or on the stock or species could 

potentially be significant (Lusseau and 

Bejder, 2007). Given the many 

uncertainties in predicting the quantity 

and types of impacts of noise on marine 

mammals, it is common practice to 

estimate how many mammals are likely 

to be present within a particular 

distance of industrial activities, or 

exposed to a particular level of 

industrial sound. This practice 

potentially overestimates the numbers 

of marine mammals that are affected in 

some biologically-important manner. 

The sound exposure thresholds that 

are used to estimate how many marine 

mammals might be harassed by a 

seismic survey are based on behavioral 

observations during studies of several 

species. However, information is lacking 

for many species. Detailed studies have 

been done on humpback, gray, 

bowhead, and on ringed seals. Less 

detailed data are available for some 

other species of baleen whales, sperm 

whales, small toothed whales, and sea 

otters, but for many species there are no 

data on responses to marine seismic 

surveys. Most of those studies have 

concerned reactions to much larger 

airgun sources than planned for use in 

the proposed project. Thus, effects are 

expected to be limited to considerably 

smaller distances and shorter periods of 

exposure in the present project than in 

most of the previous work concerning 

marine mammal reactions to airguns. 

Baleen Whales – Baleen whales 

generally tend to avoid operating 

airguns, but avoidance radii are quite 

variable. Whales are often reported to 

show no overt reactions to pulses from 

large arrays of airguns at distances 

beyond a few kilometers, even though 

the airgun pulses remain well above 

ambient noise levels out to much longer 

distances. However, as reviewed in 

Appendix A(5) of SIO’s application, 

baleen whales exposed to strong noise 

pulses from airguns often react by 

deviating from their normal migration 

route and/or interrupting their feeding 

activities and moving away from the 

sound source. In the case of the 

migrating gray and bowhead whales, the 

observed changes in behavior appeared 

to be of little or no biological 

consequence to the animals. They 

simply avoided the sound source by 

displacing their migration route to 

varying degrees, but within the natural 

boundaries of the migration corridors. 

Studies of gray, bowhead, and 

humpback whales have demonstrated 

that received levels of pulses in the 

160–170 dB re 1 μPa rms range seem to 

cause obvious avoidance behavior in a 

substantial fraction of the animals 

exposed. In many areas, seismic pulses 

from large arrays of airguns diminish to 

those levels at distances ranging from 

4.5–14.5 km (2.8–9 mi) from the source. 

A substantial proportion of the baleen 

whales within those distances may 

show avoidance or other strong 

disturbance reactions to the airgun 

array. Subtle behavioral changes 

sometimes become evident at somewhat 

lower received levels, and studies 

summarized in Appendix A(5) of SIO’s 

application have shown that some 

species of baleen whales, notably 

bowhead and humpback whales, at 

times show strong avoidance at received 

levels lower than 160–170 dB re 1 μPa 

(rms). Reaction distances would be 

considerably smaller during the 

proposed project, for which the 160 dB 

radius is predicted to be 220 to 570 m 

(722 to 1,870 ft) (see Table 1 above), as 

compared with several km when a large 

array of airguns is operating. 

Responses of humpback whales to 

seismic surveys have been studied 

during migration, on the summer 

feeding grounds, and on Angolan winter 

breeding grounds; there has also been 

discussion of effects on the Brazilian 

wintering grounds. McCauley et al. 

(1998, 2000a) studied the responses of 

humpback whales off Western Australia 

to a full-scale seismic survey with a 16– 

airgun, 2,678 in3 array, and to a single 

20 in3 airgun with a source level of 227 

dB re 1 μPa m peak-to-peak. McCauley 

et al. (1998) documented that initial 

avoidance reactions began at 5 to 8 km 

(3.1 to 5 mi) from the array, and that 

those reactions kept most pods 

approximately 3 to 4 km (1.9 to 2.5 mi) 

from the operating seismic boat. 

McCauley et al. (2000) noted localized 

displacement during migration of 4 to 5 

km (2.5 to 3.1 mi) by traveling pods and 

7 to12 km (4.3 to 7.5 mi) by cow-calf 

pairs. Avoidance distances with respect 

to the single airgun were smaller (2 km 

(1.2 mi)) but consistent with the results 

from the full array in terms of received 

sound levels. The mean received level 

for initial avoidance reactions of an 

approaching airgun was a sound level of 

140 dB re 1 μPa (rms) for humpback 

whale pods containing females. The 

standoff range, i.e., the closest point of 

approach (CPA) of the whales to the 

airgun, corresponded to a received level 

of 143 dB re 1 μPa (rms). The initial 

avoidance response generally occurred 

at distances of 5 to 8 km (3.1 to 5 mi) 

from the airgun array and 2 km (1.2 mi) 

from the single airgun. However, some 

individual humpback whales, especially 

males, approached within distances of 

100 to 400 m (328 to 1,312 ft), where the 

maximum received level was 179 dB re 

1 μPa (rms). 

Humpback whales on their summer 

feeding grounds in southeast Alaska did 

not exhibit persistent avoidance when 

exposed to seismic pulses from a 1.64– 

L (100 in3) airgun (Malme et al., 1985). 

Some humpbacks seemed ‘‘startled’’ at 

received levels of 150–169 dB re 1 μPa 

on an approximate rms basis. Malme et 

al. (1985) concluded that there was no 

clear evidence of avoidance, despite the 

possibility of subtle effects, at received 

levels up to 172 re 1 μPa on an 

approximate rms basis. 

Among wintering humpback whales 

off Angola (n = 52 useable groups), there 

were no significant differences in 

encounter rates (sightings/hr) when a 24 

airgun array (3,147 in3 or 5,805 in3) was 

operating vs. silent (Weir, 2008). There 

was also no significant difference in the 

mean CPA distance of the humpback 

whale sightings when airguns were on 

vs. off (3,050 m vs. 2,700 m or 10,007 

vs. 8,858 ft, respectively). 

It has been suggested that South 

Atlantic humpback whales wintering off 

Brazil may be displaced or even strand 

upon exposure to seismic surveys (Engel 

et al., 2004). The evidence for this was 

circumstantial and subject to alternative 

explanations (IAGC, 2004). Also, the 

evidence was not consistent with 

subsequent results from the same area of 

Brazil (Parente et al., 2006), or with 

results from direct studies of 

humpbacks exposed to seismic surveys 

in other areas and seasons. After 

allowance for data from subsequent 

years, there was ‘‘no observable direct 

correlation’’ between strandings and 

seismic surveys (IWC, 2007b:236). 

There are no data on reactions of right 

whales to seismic surveys, but results 

from the closely-related bowhead whale 

show that their responsiveness can be 

quite variable depending on the activity 

(e.g., migrating vs. feeding). Bowhead 

whales migrating west across the 

Alaskan Beaufort Sea in autumn, in 

particular, are unusually responsive, 

with substantial avoidance occurring 

out to distances of 20–30 km (12.4–18.6 

mi) from a medium-sized airgun source 

at received sound levels of around 120– 

130 dB re 1 μPa (rms) (Miller et al., 

1999; Richardson et al., 1999; see 

Appendix B (5) of L-DEO’s application). 

However, more recent research on 

bowhead whales (Miller et al., 2005a; 

Harris et al., 2007) corroborates earlier 

evidence that, during the summer 

feeding season, bowheads are not as 

sensitive to seismic sources. 

Nonetheless, subtle but statistically 

significant changes in surfacingrespiration-dive cycles were evident 

Federal Register / Vol. 74, No. 99 / Tuesday, May 26, 2009 / Notices 24807 

upon statistical analysis (Richardson et 

al., 1986). In summer, bowheads 

typically begin to show avoidance 

reactions at a received level of about 

160–170 dB re 1 μPa (rms) (Richardson 

et al., 1986; Ljungblad et al., 1988; 

Miller et al., 2005a). 

Reactions of migrating and feeding 

(but not wintering) gray whales to 

seismic surveys have been studied. 

Malme et al. (1986, 1988) studied the 

responses of feeding Eastern Pacific gray 

whales to pulses from a single 100 in3

airgun off St. Lawrence Island in the 

northern Bering Sea. Malme et al. (1986, 

1988) estimated, based on small sample 

sizes, that 50 percent of feeding gray 

whales ceased feeding at an average 

received pressure level of 173 dB re 1 

μPa on an (approximate) rms basis, and 

that 10 percent of feeding whales 

interrupted feeding at received levels of 

163 dB. Those findings were generally 

consistent with the results of 

experiments conducted on larger 

numbers of gray whales that were 

migrating along the California coast 

(Malme et al., 1984; Malme and Miles, 

1985), and with observations of Western 

Pacific gray whales feeding off Sakhalin 

Island, Russia, when a seismic survey 

was underway just offshore of their 

feeding area (Gailey et al., 2007; 

Johnson et al., 2007; Yazvenko et al. 

2007a,b), along with data on gray 

whales off British Columbia (Bain and 

Williams, 2006). Gray whales typically 

show no conspicuous responses to 

airgun pulses with received levels up to 

150 to 160 dB re 1 μPa (rms), but are 

increasingly likely to show avoidance as 

received levels increase above that 

range. 

Various species of Balaenoptera (blue, 

sei, fin, Bryde’s, and minke whales) 

have occasionally been reported in areas 

ensonified by airgun pulses (Stone, 

2003; MacLean and Haley, 2004; Stone 

and Tasker, 2006). Sightings by 

observers on seismic vessels off the 

United Kingdom from 1997 to 2000 

suggest that, at times of good 

sightability, sighting rates for mysticetes 

(mainly fin and sei whales) were similar 

when large arrays of airguns were 

shooting and not shooting (Stone, 2003; 

Stone and Tasker, 2006). However, these 

whales tended to exhibit localized 

avoidance, remaining significantly (on 

average) from the airgun array during 

seismic operations compared with nonseismic periods (Stone and Tasker, 

2006). In a study off Nova Scotia, 

Moulton and Miller (2005) found little 

difference in sighting rates (after 

accounting for water depth) and initial 

sighting distances of balaenopterid 

whales when airguns were operating vs. 

silent. However, there were indications 

that these whales were more likely to be 

moving away when seen during airgun 

operations. Similarly, ship-based 

monitoring studies of blue, fin, sei, and 

minke whales offshore of 

Newfoundland (Orphan Basin and 

Laurentian Sub-basin) found no more 

than small differences in sighting rates 

and swim direction during seismic vs. 

non-seismic periods (Moulton et al., 

2005, 2006a,b). 

Data on short-term reactions (or lack 

of reactions) of cetaceans to impulsive 

noises do not necessarily provide 

information about long-term effects. It is 

not known whether impulsive noises 

affect reproductive rate or distribution 

and habitat use in subsequent days or 

years. However, gray whales continued 

to migrate annually along the west coast 

of North America with substantial 

increases in the population over recent 

years, despite intermittent seismic 

exploration and much ship traffic in 

that area for decades (see Appendix A 

in Malme et al., 1984; Richardson et al., 

1995; Angliss and Outlaw, 2008). The 

Western Pacific gray whale population 

did not seem affected by a seismic 

survey in its feeding ground during a 

prior year (Johnson et al., 2007). 

Bowhead whales continued to travel to 

the eastern Beaufort Sea each summer, 

and their numbers have increased 

notably, despite seismic exploration in 

their summer and autumn range for 

many years (Richardson et al., 1987). In 

any event, brief exposures to sound 

pulses from the proposed airgun source 

are highly unlikely to result in 

prolonged effects. 

Toothed Whales – Little systematic 

information is available about reactions 

of toothed whales to noise pulses. Few 

studies similar to the more extensive 

baleen whale/seismic pulse work 

summarized above have been reported 

for toothed whales. However, systematic 

studies on sperm whales have been 

done (Jochens and Biggs, 2003; Tyack et 

al., 2003; Jochens et al., 2006; Miller et 

al., 2006), and there is an increasing 

amount of information about responses 

of various odontocetes to seismic 

surveys based on monitoring studies 

(Stone, 2003; Smultea et al., 2004; 

Moulton and Miller, 2005; Bain and 

Williams, 2006; Holst et al., 2006; Stone 

and Tasker, 2006; Potter et al., 2007; 

Weir, 2008). 

Seismic operators and MMOs on 

seismic vessels regularly see dolphins 

and other small toothed whales near 

operating airgun arrays, but in general 

there seems to be a tendency for most 

delphinids to show some avoidance of 

operating seismic vessels (Goold, 

1996a,b,c; Calambokidis and Osmek, 

1998; Stone, 2003; Moulton and Miller, 

2005; Holst et al., 2006; Stone and 

Tasker, 2006; Weir, 2008). Some 

dolphins seem to be attracted to the 

seismic vessel and floats, and some ride 

the bow wave of the seismic vessel even 

when large airgun arrays are firing 

(Moulton and Miller, 2005). 

Nonetheless, there have been 

indications that small toothed whales 

sometimes tend to head away or to 

maintain a somewhat greater distance 

from the vessel, when a large array of 

airguns is operating than when it is 

silent (Stone and Tasker, 2006; Weir, 

2008). In most cases, the avoidance radii 

for delphinids appear to be small, on the 

order of 1 km (0.62 mi) or less, and 

some individuals show no apparent 

avoidance. The beluga is a species that 

(at least at times) shows long-distance 

avoidance of seismic vessels. Aerial 

surveys during seismic operations in the 

southeastern Beaufort Sea during 

summer recorded much lower sighting 

rates of beluga whales within 10–20 km 

(6.2–12.4 mi) compared with 20–30 km 

(mi) from an operating airgun array, and 

observers on seismic boats in that area 

rarely see belugas (Miller et al., 2005a; 

Harris et al., 2007). 

Captive bottlenose dolphins and 

beluga whales exhibited changes in 

behavior when exposed to strong pulsed 

sounds similar in duration to those 

typically used in seismic surveys 

(Finneran et al., 2000, 2002, 2005; 

Finneran and Schlundt, 2004). The 

animals tolerated high received levels of 

sound (pk-pk level >200 dB re 1 μPa) 

before exhibiting aversive behaviors. For 

pooled data at 3, 10, and 20 kHz, sound 

exposure levels during sessions with 25, 

50, and 75 percent altered behavior 

were 180, 190, and 199 dB re 1 μPa2, 

respectively (Finneran and Schlundt, 

2004). 

Results for porpoises depend on 

species. Dall’s porpoises seem relatively 

tolerant of airgun operations (MacLean 

and Koski, 2005) and, during a survey 

with a large airgun array, tolerated 

higher noise levels than did harbor 

porpoises and gray whales (Bain and 

Williams, 2006). However, Dall’s 

porpoises do respond to the approach of 

large airgun arrays by moving away 

(Calambokidis and Osmek, 1998; Bain 

and Williams, 2006). The limited 

available data suggest that harbor 

porpoises show stronger avoidance 

(Stone, 2003; Bain and Williams, 2006; 

Stone and Tasker, 2006). This apparent 

difference in responsiveness of these 

two porpoise species is consistent with 

their relative responsiveness to boat 

traffic and some other acoustic sources 

in general (Richardson et al., 1995; 

Southall et al. 2007). 

24808 Federal Register / Vol. 74, No. 99 / Tuesday, May 26, 2009 / Notices 

Most studies of sperm whales exposed 

to airgun sounds indicate that this 

species shows considerable tolerance of 

airgun pulses (Stone, 2003; Moulton et 

al., 2005, 2006a; Stone and Tasker, 

2006; Weir, 2008). In most cases, the 

whales do not show strong avoidance 

and continue to call (see Appendix A in 

SIO’s application). However, controlled 

exposure experiments in the Gulf of 

Mexico indicate that foraging effort is 

somewhat altered upon exposure to 

airgun sounds (Jochens et al., 2006, 

2008). In the SWSS study, D-tags 

(Johnson and Tyack, 2003) were used to 

record the movement and acoustic 

exposure of eight foraging sperm whales 

before, during, and after controlled 

sound exposures of airgun arrays in the 

Gulf of Mexico (Jochens et al., 2008). 

Whales were exposed to maximum 

received sound levels between 111 and 

147 dB re 1 μPa (rms) (131 to 164 dB 

re 1 μPa pk-pk) at ranges of 

approximately 1.4 to 12. 6 km (0.9 to 7.8 

mi) from the sound source. Although 

the tagged whales showed no horizontal 

avoidance, some whales changed 

foraging behavior during full array 

exposure (Jochens et al., 2008). 

There are almost no specific data on 

the behavioral reactions of beaked 

whales to seismic surveys. However, 

northern bottlenose whales (Hyperodon 

ampullatus) continued to produce highfrequency clicks when exposed to sound 

pulses from distant seismic surveys 

(Laurinolli and Cochrane, 2005; Simard 

et al., 2005). Most beaked whales tend 

to avoid approaching vessels of other 

types (Wursig et al., 1998). They may 

also dive for an extended period when 

approached by a vessel (Kasuya, 1986), 

although it is uncertain how much 

longer such dives may be as compared 

to dives by undisturbed beaked whales, 

which also are often quire long (Baird et 

al., 2006; Tyack et al., 2006). In any 

event, it is likely that these beaked 

whales would normally show strong 

avoidance of an approaching seismic 

vessel, but this has not been 

documented explicitly. 

Odontocete reactions to large arrays of 

airguns are variable and, at least for 

delphinids and Dall’s porpoises, seem to 

be confined to a smaller radius than has 

been observed for the more responsive 

of the mysticetes, belugas, and harbor 

porpoises (Appendix A of SIO’s 

application). 

Additional details on the behavioral 

reactions (or the lack thereof) by all 

types of marine mammals to seismic 

vessels can be found in Appendix A(5) 

of SIO’s 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 this for marine 

mammals exposed to sequences of 

airgun pulses. 

NMFS will be developing new noise 

exposure criteria for marine mammals 

that take account of the now-available 

scientific data on temporary threshold 

shift (TTS), the expected offset between 

the TTS and permanent threshold shift 

(PTS) thresholds, differences in the 

acoustic frequencies to which different 

marine mammal groups are sensitive, 

and other relevant factors. Detailed 

recommendations for new science-based 

noise exposure criteria were published 

in late 2007 (Southall et al., 2007). 

Several aspects of the planned 

monitoring and mitigation measures for 

this project (see below) are designed to 

detect marine mammals occurring near 

the airguns to avoid exposing them to 

sound pulses that might, at least in 

theory, cause hearing impairment. In 

addition, many cetaceans and (to a 

limited degree) pinnipeds are likely to 

show some avoidance of the area where 

received levels of airgun sound are high 

enough such that hearing impairment 

could potentially occur. In those cases, 

the avoidance responses of the animals 

themselves will reduce or (most likely) 

avoid any 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, as discussed 

below, there is no definitive evidence 

that any of these effects occur even for 

marine mammals in close proximity to 

large arrays of airguns. It is especially 

unlikely that any effects of these types 

would occur during the present project 

given the brief duration of exposure of 

any given mammal and the proposed 

monitoring and mitigation measures 

(see below). The following subsections 

discuss in somewhat more detail the 

possibilities of TTS, PTS, and nonauditory physical effects. 

Temporary Threshold Shift – TTS is 

the mildest form of hearing impairment 

that can occur during exposure to a 

strong sound (Kryter, 1985). While 

experiencing TTS, the hearing threshold 

rises and a sound must be stronger in 

order to be heard. At least in terrestrial 

mammals, TTS can last from minutes or 

hours to (in cases of strong TTS) days. 

For sound exposures at or somewhat 

above the TTS threshold, hearing 

sensitivity in both terrestrial and marine 

mammals recovers rapidly after 

exposure to the noise ends. Few data on 

sound levels and durations necessary to 

elicit mild TTS have been obtained for 

marine mammals, and none of the 

published data concern TTS elicited by 

exposure to multiple pulses of sound. 

Available data on TTS in marine 

mammals are summarized in Southall et 

al. (2007). 

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, 2005). 

Given the available data, the received 

level of a single seismic pulse (with no 

frequency weighting) might need to be 

approximately 186 dB re 1 μPa2.s (i.e., 

186 dB SEL or approximately 221–226 

dB pk-pk) in order to produce brief, 

mild TTS. Exposure to several strong 

seismic pulses that each have received 

levels near 190 dB re 1 μPa (rms) (175– 

180 dB SEL) might result in cumulative 

exposure of approximately 186 dB SEL 

and thus slight TTS in a small 

odontocete, assuming the TTS threshold 

is (to a first approximation) a function 

of the total received pulse energy. 

Levels ≥ 190 dB 1 μPa (rms) are 

expected to be restricted to radii no 

more than 95 m (312 ft) from the 

Wecoma’s GI airgun. For an odontocete 

closer to the surface, the maximum 

radius with ≥190 dB 1 μPa (rms) would 

be smaller. 

The above TTS information for 

odontocetes is derived from studies on 

the bottlenose dolphin and beluga. 

There is not published TTS information 

for other species of cetaceans. However, 

preliminary evidence from harbor 

porpoise exposed to airgun sound 

suggests that its TTS threshold may 

have been lower (Lucke et al., 2007). 

For baleen whales, there are no data, 

direct or indirect, on levels or properties 

of sound required to induce TTS. The 

frequencies to which baleen whales are 

most sensitive are lower than those for 

odontocetes, and natural background 

noise levels at those low frequencies 

tend to be higher. As a result, auditory 

thresholds of baleen whales within their 

frequency band of best hearing are 

believed to be higher (less sensitive) 

Federal Register / Vol. 74, No. 99 / Tuesday, May 26, 2009 / Notices 24809 

than are those of odontocetes at their 

best frequencies (Clark and Ellison, 

2004). From this, it is suspected that 

received levels causing TTS onset may 

also be higher in baleen whales. In any 

event, no cases of TTS are expected 

given three considerations: 

(1) Small size of the GI airgun source; 

(2) The strong likelihood that baleen 

whales would avoid the approaching 

airguns (or vessel) before being exposed 

to levels high enough for TTS to 

possibly occur; and 

(3) The mitigation measures that are 

planned. 

In pinnipeds, TTS thresholds 

associated with exposure to brief pulses 

(single or multiple) of underwater sound 

have not been measured. Initial 

evidence from prolonged (non-pulse) 

exposures suggested that some 

pinnipeds may incur TTS at somewhat 

lower received levels than do small 

odontocetes exposed for similar 

durations (Kastak et al., 1999, 2005; 

Ketten et al., 2001; Au et al., 2000). The 

TTS threshold for pulsed sounds has 

been indirectly estimated as being an 

SEL of approximately 171 dB re 1 μPa2.s 

(Southall et al., 2007), which would be 

equivalent to a single pulse with 

received level approximately 181–186 re 

1 μPa (rms), or a series of pulses for 

which the highest rms values are a few 

dB lower. Corresponding values for 

California sea lions and northern 

elephant seals are likely to be higher 

(Kastak et al., 2005). 

A marine mammal within a radius of 

less than 100 m (328 ft) around a typical 

large array of operating airguns might be 

exposed to a few seismic pulses with 

levels of greater than or equal to 205 dB, 

and possibly more pulses if the mammal 

moved with the seismic vessel. (As 

noted above, most cetacean species tend 

to avoid operating airguns, although not 

all individuals do so.) In addition, 

ramping up airgun arrays, which is 

standard operational protocol for large 

airgun arrays and proposed for this 

action, should allow cetaceans to move 

away form the seismic source and avoid 

being exposed to the full acoustic 

output of the airgun array. Even with a 

large airgun array, it is unlikely that the 

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. The potential for TTS is much 

lower in this project. With a large array 

of airguns, TTS would be most likely in 

any odontocetes that bow-ride or 

otherwise linger near the airguns. While 

bow-riding, odontocetes would be at or 

above the surface, and thus not exposed 

to strong 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. If some 

cetaceans did incur TTS through 

exposure to airgun sounds, this would 

very likely be mild, temporary, and 

reversible. 

To avoid the potential for injury, 

NMFS has determined that cetaceans 

and pinnipeds should not be exposed to 

pulsed underwater noise at received 

levels exceeding, respectively, 180 and 

190 dB re 1 μPa (rms). As summarized 

above, data that are now available imply 

that TTS is unlikely to occur unless 

odontocetes (and probably mysticetes as 

well) are exposed to airgun pulses 

stronger than 180 dB re 1 μPa (rms). 

Permanent Threshold Shift – When 

PTS occurs, there is physical damage to 

the sound receptors in the ear. In severe 

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 

(Kryter, 1985). 

There is no specific evidence that 

exposure to pulses of airgun sound can 

cause PTS in any marine mammal, even 

with large arrays of airguns. However, 

given the possibility that mammals 

close to an airgun array might incur 

TTS, there has been further speculation 

about the possibility that some 

individuals occurring very close to 

airguns might incur PTS (Richardson et 

al., 1995). Single or occasional 

occurrences of mild TTS are not 

indicative of permanent auditory 

damage. 

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. PTS might occur at 

a received sound level at least several 

decibels above that inducing mild TTS 

if the animal were exposed to strong 

sound pulses with rapid rise time (see 

Appendix A(5) of SIO’s application). 

Based on data from terrestrial mammals, 

a precautionary assumption is that the 

PTS threshold for impulse sounds (such 

as airgun pulses as received close to the 

source) is at least 6 dB higher than the 

TTS threshold on a peak-pressure basis, 

and probably >6 dB (Southall et al., 

2007). On an SEL basis, Southall et al. 

(2007) estimated that received levels 

would need to exceed the TTS threshold 

by at least 15 dB for there to be risk of 

PTS. Thus, for cetaceans they estimate 

that the PTS threshold might be an Mweighted SEL (for the sequence of 

received pulses) of approximately 198 

dB re 1 μPa2μs (15 dB higher than the 

TTS threshold for an impulse). 

Additional assumptions had to be made 

to derive a corresponding estimate for 

pinnipeds, as the only available data on 

TTS thresholds in pinnipeds pertain to 

non-impulse sound. Southall et al. 

(2007) estimate that the PTS threshold 

could be a cumulative Mpw-weighted 

SEL of approximately 186 dB 1 μPa2.s in 

the harbor seal to impulse sound. The 

PTS threshold for the California sea lion 

and northern elephant seal the PTS 

threshold would probably be higher, 

given the higher TTS thresholds in 

those species. 

Southall et al. (2007) also note that, 

regardless of the SEL, there is concern 

about the possibility of PTS if a cetacean 

or pinniped receives one or more pulses 

with peak pressure exceeding 230 or 

218 dB re 1 μPa (3.2 bar. m, 0–pk), 

which would only be found within a 

few meters of the largest (600–in3) 

airguns in the planned airgun array 

(Caldwell and Dragoset, 2000). A peak 

pressure of 218 dB re 1 μPa could be 

received somewhat farther away; to 

estimate that specific distance, one 

would need to apply a model that 

accurately calculates peak pressures in 

the near-field around an array of 

airguns. 

Given the higher level of sound 

necessary to cause PTS as compared 

with TTS, it is considerably less likely 

that PTS could occur. Baleen whales 

generally avoid the immediate area 

around operating seismic vessels, as do 

some other marine mammals. The 

planned monitoring and mitigation 

measures, including visual monitoring 

and shut downs of the airguns when 

mammals are seen about to enter or 

within the proposed exclusion zone 

(EZ), will further reduce the probability 

of exposure of marine mammals to 

sounds strong enough to induce PTS, 

see the section below on Proposed 

Mitigation and Monitoring. 

Non-auditory Physiological Effects – 

Non-auditory physiological effects or 

injuries that theoretically might occur in 

marine mammals exposed to strong 

underwater sound include stress, 

neurological effects, bubble formation, 

resonance effects, and other types of 

organ or tissue damage (Cox et al., 2006; 

Southall et al., 2007). Studies examining 

such effects are limited. However, 

resonance (Gentry, 2002) and direct 

noise-induced bubble formation (Crum 

et al., 2005) are not expected in the case 

of an impulsive source like an airgun 

array. If seismic surveys disrupt diving 

patterns of deep diving species, this 

might perhaps result in bubble 

formation and a form of ‘‘the bends,’’ as 

speculated to occur in beaked whales 

exposed to sonar. However, there is no 

24810 Federal Register / Vol. 74, No. 99 / Tuesday, May 26, 2009 / Notices 

specific evidence of this upon exposure 

to airgun pulses. 

In general, little is known about the 

potential for seismic survey sounds to 

cause auditory impairment or other 

physical effects in marine mammals. 

Available data suggest that such effects, 

if they occur at all, would presumably 

be limited to short distances from the 

sound source and to activities that 

extend over a prolonged period. The 

available data do not allow 

identification of a specific exposure 

level above which non-auditory effects 

can be expected (Southall et al., 2007), 

or any meaningful quantitative 

predictions of the numbers (if any) of 

marine mammals that might be affected 

in those ways. Marine mammals that 

show behavioral avoidance of seismic 

vessels, including most baleen whales, 

some odontocetes, and some pinnipeds, 

are especially unlikely to incur auditory 

impairment or non-auditory physical 

effects. Also, the planned mitigation 

measures, including shut downs of the 

airgun, would reduce any such effects 

that might otherwise occur. 

Strandings and Mortality 

Marine mammals close to underwater 

detonations of high explosives can be 

killed or severely injured, and their 

auditory organs are especially 

susceptible to injury (Ketten et al., 1993; 

Ketten, 1995). However, explosives are 

no longer used for marine seismic 

research or commercial seismic surveys, 

and have been replaced entirely by 

airguns or related non-explosive pulse 

generators. Airgun pulses are less 

energetic and have slower rise times, 

and there is no specific evidence that 

they can cause injury, death, or 

stranding even in the case of large 

airgun arrays. However, the association 

of mass strandings of beaked whales 

with naval exercises and, in one case, an 

L-DEO seismic survey (Malakoff, 2002; 

Cox et al., 2006), has raised the 

possibility that beaked whales exposed 

to strong ‘‘pulsed’’ sounds may be 

especially susceptible to injury and/or 

behavioral reactions that can lead to 

stranding (Hildebrand, 2005; Southall et 

al., 2007). Appendix A(5) of SIO’s 

application provides additional details. 

Specific sound-related processes that 

lead to strandings and mortality are not 

well documented, but may include: 

(1) Swimming in avoidance of a 

sound into shallow water; 

(2) A change in behavior (such as a 

change in diving behavior) that might 

contribute to tissue damage, gas bubble 

formation, hypoxia, cardiac arrhythmia, 

hypertensive hemorrahage or other 

forms of trauma; 

(3) A physiological change such as a 

vestibular response leading to a 

behavioral change or stress-induced 

hemorrahagic diathesis, leading in turn 

to tissue damage; and 

(4) Tissue damage directly from sound 

exposure, such as through acoustically 

mediated bubble formation and growth 

or acoustic resonance of tissues. 

As noted in SIO’s application, some of 

these mechanisms are unlikely to apply 

in the case of impulse sounds. However, 

there are increasing indications that gasbubble disease (analogous to ‘‘the 

bends’’), induced in super-saturated 

tissue by a behavioral response to 

acoustic exposure, could be pathologic 

mechanism for the strandings and 

mortality of some deep diving cetaceans 

exposed to sonar. The evidence for this 

remains circumstantial and associated 

with exposure to naval mid-frequency 

sonar, not seismic surveys (Cox et al., 

2006; Southall et al., 2007). 

Seismic pulses and mid-frequency 

sonar pulses are quite different, and 

some mechanisms by which sonar 

sounds have been hypothesized to affect 

beaked whales are unlikely to apply to 

airgun pulses. Sounds produced by 

airgun arrays are broadband with most 

of the energy below 1 kHz. Typical 

military mid-frequency sonars operate at 

frequencies of 2–10 kHz, generally with 

a relatively narrow bandwidth at any 

one time. A further difference between 

seismic surveys and naval exercises is 

that naval exercises can involve sound 

sources on more than one vessel. Thus, 

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 (at least 

indirectly) to physical damage and 

mortality (Balcomb and Claridge, 2001; 

NOAA and USN, 2001; Jepson et al., 

2003; Fernandez et al., 2004, 2005a,b; 

Hildebrand, 2005; Cox et al., 2006) 

suggests that caution is warranted when 

dealing with exposure of marine 

mammals to any high-intensity pulsed 

sound. 

There is no conclusive evidence of 

cetacean strandings or deaths at sea as 

a result of exposure to seismic surveys, 

but a few cases of strandings in the 

general area where a seismic survey was 

ongoing have led to speculation 

concerning a possible link between 

seismic surveys and strandings. 

Suggestions that there was a link 

between seismic surveys and strandings 

of humpback whales in Brazil (Engel et 

al., 2004) was not well founded based 

on available data (IAGC, 2004; IWC, 

2006). In September 2002, there was a 

stranding of two Cuvier’s beaked whales 

(Ziphius cavirostris) in the Gulf of 

California, Mexico, when the L-DEO 

vessel R/V Maurice Ewing (Ewing) was 

operating a 20–gun, 8,490–in3 array in 

the general area. The link between the 

stranding and the seismic survey was 

inconclusive and not based on any 

physical evidence (Hogarth, 2002; 

Yoder, 2002). Nonetheless, the Gulf of 

California incident plus the beaked 

whale strandings near naval exercises 

involving use of mid-frequency sonar 

suggests a need for caution when 

conducting seismic surveys in areas 

occupied by beaked whales until more 

is known about effects of seismic 

surveys on those species (Hildebrand, 

2005). 

No injuries of beaked whales are 

anticipated during the proposed study 

because of (1) the high likelihood that 

any beaked whales nearby would avoid 

the approaching vessel before being 

exposed to high sound levels, (2) the 

proposed monitoring and mitigation 

measures, including avoiding submarine 

canyons, where deep diving species 

may congregate, and (3) differences 

between the sound sources operated by 

SIO and those involved in the naval 

exercises associated with strandings. 

Potential Effects of Other Acoustic 

Devices 

Sub-bottom Profiler Signals 

A SBP will be operated from the 

source vessel at all times during the 

planned study. Sounds from the SBP are 

very short pulses, occurring for 12 or 24 

ms once every 4.5 to 8 seconds. Most of 

the energy in the sound pulses emitted 

by the SBP is at mid frequencies, 

centered at 3.5 kHz. The beamwidth is 

approximately 80° and is directed 

downward. 

The SBP on the Wecoma has a 

maximum source level of 211 dB re 1 

μPam. Thus the received level would be 

expected to decrease to 180 dB and 160 

dB approximately 35 m (115 ft) and 350 

m (1,148 ft) below the transducer, 

respectively, assuming spherical 

spreading. Corresponding distances in 

the horizontal plane would be 

substantially lower, given the 

directionality of this source. Kremser et 

al. (2005) noted that the probability of 

a cetacean swimming through the area 

of exposure when a bottom profiler 

emits a pulse is small, and if the animal 

was in the area, it would have to pass 

the transducer at close range in order to 

be subjected to sound levels that could 

cause TTS. 

Marine mammal communications will 

not be masked appreciably by the SBP 

signals given their directionality and the 

brief period when an individual 

Federal Register / Vol. 74, No. 99 / Tuesday, May 26, 2009 / Notices 24811 

mammal is likely to be within its beam. 

Furthermore, in the case of most 

odontocetes, the signals do not overlap 

with the predominant frequencies in the 

calls, which would avoid significant 

masking. 

Marine mammal behavioral reactions 

to other pulsed sound sources are 

discussed above, and responses to the 

SBP are likely to be similar to those for 

other pulsed sources if received at the 

same levels. Therefore, behavioral 

responses are not expected unless 

marine mammals are very close to the 

source. 

The source levels of the SBP are much 

lower than those of the airgun. It is 

unlikely that the SBP 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 SBP 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 

SBP. 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 other sources would 

further reduce or eliminate any minor 

effects of the SBP. 

As stated above, NMFS is assuming 

that Level A harassment onset 

corresponds to 180 and 190 dB re 1 μPa 

(rms) for cetaceans and pinnipeds, 

respectively. The precautionary nature 

of these criteria is discussed in 

Appendix A(5) of SIO’s application, 

including the fact that 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 and the 

level associated with the onset of TTS 

is often considered to be a level below 

which there is no danger of permanent 

damage. NMFS also assumes that 

cetaceans or pinnipeds exposed to 

levels exceeding 160 dB re 1 μPa (rms) 

may experience Level B harassment. 

Possible Effects of Acoustic Release 

Signals 

The acoustic release transponder used 

to communicate with the OBSs uses 

frequencies of 9–13 kHz. Once the OBS 

is ready to be retrieved, an acoustic 

release transponder interrogates the 

OBS at a frequency of 9–11 kHz, and a 

response is received at a frequency of 9– 

13 kHz. The burn wire release is then 

activated, and the instrument is released 

from the anchor to float to the surface. 

These signals will be used very 

intermittently. It is unlikely that the 

acoustic release signals would have 

effects on marine mammals through 

masking, disturbance, or hearing 

impairment. Any effects likely would be 

de minimus given the brief exposure at 

low levels. 

Estimated Take by Incidental 

Harassment 

All anticipated takes would be ‘‘takes 

by harassment,’’ involving temporary 

changes in behavior. The proposed 

monitoring and mitigation measures are 

expected to minimize the possibility of 

injurious takes. (However, as noted 

earlier, there is no specific information 

demonstrating that injurious ‘‘takes’’ 

would occur even in the absence of the 

planned monitoring and mitigation 

measures.) The sections below describe 

methods to estimate ‘‘take by 

harassment’’, and present estimates of 

the numbers of marine mammals that 

might be affected during the proposed 

seismic program. The estimates of ‘‘take 

by harassment’’ are based on (1) data 

concerning marine mammal densities 

(numbers per unit area) obtained during 

surveys off Oregon and Washington 

during 1996, 2001, and 2005 

(cetaceans), or 1989 to 1990 (pinnipeds) 

by NMFS Southwest Fisheries Science 

Center (SWFSC), and (2) estimates of the 

size of the 160 dB isolpeths where takes 

could potentially occur from the 

proposed seismic survey off the coast of 

Oregon in the northeastern Pacific 

Ocean. 

Extensive systematic aircraft and 

ship-based surveys have been 

conducted for marine mammals offshore 

of Oregon and Washington (Bonnell et 

al., 1992; Green et al., 1992, 1993; 

Barlow 1997, 2003; Barlow and Taylor, 

2001; Calambokidis and Barlow, 2004; 

Barlow and Forney in prep.). The most 

comprehensive and recent density data 

available for cetacean species in slope 

and offshore waters of Oregon are from 

the 1996, 2001, and 2005 NMFS SWFSC 

‘‘ORCAWALE’’ or ‘‘CSCAPE’’ ship 

surveys as synthesized by Barlow and 

Forney (2007). The surveys were 

conducted up to approximately 550 km 

(342 mi) offshore from June or July to 

November or December. Systematic, 

offshore, at-sea survey data for 

pinnipeds are more limited. The most 

comprehensive such studies are 

reported by Bonnell et al. (1992) based 

on systematic aerial surveys conducted 

in 1989–1990. 

Oceanographic conditions, including 

occasional El Nino and La Nina events, 

influence the distribution and numbers 

of marine mammals present in the 

Northeast Pacific Ocean, including 

Oregon, resulting in considerable yearto-year variation in the distribution and 

abundance of many marine mammal 

species (Forney and Barlow, 1998; 

Buchanan et al., 2001; Escorza-Trevino, 

2002; Ferrero et al., 2002; Philbrick et 

al., 2003). Thus, for some species the 

densities derived from recent surveys 

may not be representative of the 

densities that will be encountered 

during the proposed seismic survey. For 

this IHA application, cruise reports from 

the ORCAWALE 2008 surveys (NMFS, 

2008) were inspected to assess whether 

there were any observable changes from 

the previous surveys of the same area. 

Table 3 of SIO’s application gives the 

average and maximum densities for 

each species of cetacean reported off 

Oregon and Washington, corrected for 

effort, based on the densities reported 

for the 1996, 2001, and 2005 surveys 

(Barlow and Forney, 2007). The 

densities from those studies had been 

corrected, by the original authors, for 

both detectability bias and availability 

bias. Detectability bias is associated 

with diminishing sightability with 

increasing lateral distance from the 

trackline. Availability bias refers to the 

fact that there is <100 percent 

probability of sighting an animals that is 

present along the survey trackline. 

Table 3 of SIO’s application also 

includes mean density information for 

three of the five pinnipeds species that 

occur off Oregon and Washington and 

mean and maximum densities for one of 

those species, from Bonnell et al. (1992). 

Densities were not calculated for the 

other two species because of the small 

number of sightings on systematic 

transect surveys. One of those, the 

northern elephant seal, was the 

dominant seal sighted during the 

ORCAWALE 2008 surveys (29 of 33 

pinnipeds sighted off Oregon and 

Washington), so it was included at a 

density set at twice that of the northern 

fur seal, the other species sighted during 

the ORCAWALE 2008 surveys. 

It should be noted that the following 

estimates of ‘‘takes by harassment’’ 

assume that the surveys will be 

undertaken and completed; in fact, the 

planned number of line kms has been 

increased by 25 percent to accommodate 

lines that may need to be repeated, 

equipment testing, etc. As is typical on 

offshore ship surveys, inclement 

weather, and equipment malfunctions 

are likely to cause delays and may limit 

the number of useful line kms of seismic 

operations that can be undertaken. 

Furthermore, any marine mammal 

sightings within or near the designated 

safety zones will result in the shutdown of seismic operations as a 

24812 Federal Register / Vol. 74, No. 99 / Tuesday, May 26, 2009 / Notices 

mitigation measure. Thus, the following 

estimates of the numbers of marine 

mammals potentially exposed to 160 dB 

are precautionary, and probably 

overestimate the actual numbers of 

marine mammals that might be 

involved. These estimates assume that 

there will be no weather, equipment, or 

mitigation delays, which is highly 

unlikely. 

There is some uncertainty about the 

representativness of the data and the 

assumption used in the calculations. 

However, the approach used is believed 

to be the best available approach. Also, 

to provide some allowance for these 

uncertainties ‘‘maximum estimates’’ as 

well as ‘‘best estimates’’ of the numbers 

potentially affected have been derived. 

Best and maximum estimates are based 

on the average and maximum estimates 

of densities reported primarily by 

Barlow and Forney (2007) and Bonnell 

et al. (1992) described above. The 

estimated numbers of potential 

individuals exposed are presented 

below based on the 160 dB re 1 μPa 

(rms) Level B harassment criterion for 

all cetaceans and pinnipeds. It is 

assumed that a marine mammal exposed 

to airgun sounds this strong might 

change their behavior sufficiently to be 

considered ‘‘taken by harassment.’’ 

The number of different individuals 

that may be exposed to GI airgun sounds 

with received levels ≥160 dB re 1 μPa 

(rms) on one or more occasions was 

estimated by considering the total 

marine area that would be within the 

160 dB radius around the operating 

airgun array on at least one occasion. 

The proposed seismic lines do not run 

parallel to each other in close proximity, 

which minimizes the number of times 

an individual mammal may be exposed 

during the survey. The best estimates in 

this section are based on the averages of 

the densities from the 1996, 2001, and 

2005 NMFS surveys, and maximum 

estimates are based on the highest of the 

three densities. Table 4 of SIO’s 

application and Table 2 of this Federal 

Register notice show the best and 

maximum estimates of the number of 

marine mammals that could potentially 

be affected during the seismic survey. 

The number of different individuals 

potentially exposed to received levels 

≥160 dB re 1 μPa (rms) was calculated 

by multiplying: 

• The expected species density, either 

‘‘mean’’ (i.e., best estimate) or 

‘‘maximum,’’ times; and 

• The area anticipated to be 

ensonified to that level during GI airgun 

operations. 

The area expected to be ensonified 

was determined by entering the planned 

survey lines into a MapInfo Geographic 

Information System (GIS), using the GIS 

to identify the relevant areas by 

‘‘drawing’’ the applicable 160 dB buffer 

around each seismic line (depending on 

water and tow depth) and then 

calculating the total area within the 

buffers. Areas where overlap occurred 

(because of intersecting lines) were 

included only once to determine the 

area expected to be ensonified. In the 

proposed survey, there is minimal 

overlap (5 percent for 160 dB), so 

virtually no marine mammal would be 

ensonified above those thresholds more 

than once. 

Applying the approach described 

above, approximately 208 km2 (80.3 

mi2) would be within the 160 dB 

isopleth on one or more occasions 

during the surveys at all 16 OBS 

locations. For inshore OBS locations, 

approximately 60 km2 (23 mi2) would 

be within the 160 dB isopleths; that area 

was used for calculations for the 

pinniped species that could occur only 

at those locations. This approach does 

not allow for turnover in the mammal 

populations in the study area during the 

course of the surveys. That might 

underestimate actual numbers of 

individuals exposed, although the 

conservative distances used to calculate 

the area may offset this. In addition, the 

approach assumes that no cetaceans will 

move away or toward the trackline as 

the Wecoma approaches, in response to 

increasing sound levels prior to the time 

the levels reach 160 dB. Another way of 

interpreting the estimates that follow in 

Table 3 (below) is that they represent 

the number of individuals that are 

expected (in the absence of a seismic 

program) to occur in the waters that will 

be exposed to ≥160 dB re 1 μPa (rms). 

TABLE 3. THE ESTIMATES OF THE POSSIBLE NUMBERS OF MARINE MAMMALS EXPOSED TO SOUND LEVELS GREATER THAN

OR EQUAL TO 160 DB DURING SIO’S PROPOSED SEISMIC SURVEY OFF OREGON IN JULY 2009. THE PROPOSED SOUND

SOURCE IS A SINGLE GI AIRGUN. RECEIVED LEVELS ARE EXPRESSED IN DB RE 1 μPA (RMS) (AVERAGED OVER PULSE

DURATION), CONSISTENT WITH NMFS’ PRACTICE. NOT ALL MARINE MAMMALS WILL CHANGE THEIR BEHAVIOR WHEN EXPOSED TO THESE SOUND LEVELS, BUT SOME MAY ALTER THEIR BEHAVIOR WHEN LEVELS ARE LOWER (SEE TEXT). SEE

TABLES 2–4 IN SIO’S APPLICATION FOR FURTHER DETAIL. 

Species # of Individuals Exposed 

(best)1

# of Individuals Exposed 

(max)1

Approx. % Regional 

Population (best)2

Mysticetes 

Eastern Pacific gray whale 

(Eschrichtius robustus) 0 0 0 

North Pacific right whale 

(Eubalaena japonica) 0 0 0 

Humpback whale 

(Megaptera novaeangliae) 0 2 0 

Minke whale(Balaenoptera acutorostrata) 0 0 0 

Sei whale(Balaenoptera borealis) 0 0 0 

Fin whale 

(Balaenoptera physalus) 0 1 0 

Blue whale 

(Balaenoptera musculus) 0 1 0 

Federal Register / Vol. 74, No. 99 / Tuesday, May 26, 2009 / Notices 24813 

TABLE 3. THE ESTIMATES OF THE POSSIBLE NUMBERS OF MARINE MAMMALS EXPOSED TO SOUND LEVELS GREATER THAN

OR EQUAL TO 160 DB DURING SIO’S PROPOSED SEISMIC SURVEY OFF OREGON IN JULY 2009. THE PROPOSED SOUND

SOURCE IS A SINGLE GI AIRGUN. RECEIVED LEVELS ARE EXPRESSED IN DB RE 1 μPA (RMS) (AVERAGED OVER PULSE

DURATION), CONSISTENT WITH NMFS’ PRACTICE. NOT ALL MARINE MAMMALS WILL CHANGE THEIR BEHAVIOR WHEN EXPOSED TO THESE SOUND LEVELS, BUT SOME MAY ALTER THEIR BEHAVIOR WHEN LEVELS ARE LOWER (SEE TEXT). SEE

TABLES 2–4 IN SIO’S APPLICATION FOR FURTHER DETAIL.—Continued 

Species # of Individuals Exposed 

(best)1

# of Individuals Exposed 

(max)1

Approx. % Regional 

Population (best)2

Odontocetes 

Sperm whale 

(Physeter macrocephalus) 0 8 0 

Pygmy sperm whale 

(Kogia breviceps) 0 1 N.A. 

Dwarf sperm whale 

(Kogia sima) 0 0 0 

Cuvier’s beaked whale 

(Ziphius cavirostris) 0 0 0 

Baird’s beaked whale 

(Berardius bairdii) 0 1 0 

Blainville’s beaked whale 

(Mesoplodon densirostris) 0 0 0 

Hubb’s beaked whale(Mesoplodon carlhubbsi) 0 0 0 

Stejneger’s beaked whale 

(Mesoplodon stejnegeri) 0 0 0 

Mesoplodon sp. 

(unidentified) 0 1 0 

Offshore bottlenose dolphin 

(Tursiops truncatus) 0 0 0 

Striped dolphin 

(Stenella coeruleoalba) 0 0 0 

Short-beaked common dolphin 

(Delphinus delphis) 4 9 <0.01 

Pacific white-sided dolphin 

Lagenorhynchus obliquidens) 6 9 0.02 

Northern right-whale dolphin 

(Lissodelphis borealis) 5 7 0.02 

Risso’s dolphin 

(Grampus griseus) 3 4 0.03 

False killer whale 

(Pseudorca crassidens) 0 0 N.A. 

Killer whale 

(Orcinus orca) 0 1 0 

Short-finned pilot whale 

(Globicephala macrorhynchus) 0 0 0 

Harbor porpoise 

(Phocoena phocoena) 0 0 0 

Dall’s porpoise 

(Phocoenoides dalli) 39 65 0.1 

Pinnipeds 

Northern fur seal 

(Callorhinus ursinus) 3 26 <0.01 

24814 Federal Register / Vol. 74, No. 99 / Tuesday, May 26, 2009 / Notices 

TABLE 3. THE ESTIMATES OF THE POSSIBLE NUMBERS OF MARINE MAMMALS EXPOSED TO SOUND LEVELS GREATER THAN

OR EQUAL TO 160 DB DURING SIO’S PROPOSED SEISMIC SURVEY OFF OREGON IN JULY 2009. THE PROPOSED SOUND

SOURCE IS A SINGLE GI AIRGUN. RECEIVED LEVELS ARE EXPRESSED IN DB RE 1 μPA (RMS) (AVERAGED OVER PULSE

DURATION), CONSISTENT WITH NMFS’ PRACTICE. NOT ALL MARINE MAMMALS WILL CHANGE THEIR BEHAVIOR WHEN EXPOSED TO THESE SOUND LEVELS, BUT SOME MAY ALTER THEIR BEHAVIOR WHEN LEVELS ARE LOWER (SEE TEXT). SEE

TABLES 2–4 IN SIO’S APPLICATION FOR FURTHER DETAIL.—Continued 

Species # of Individuals Exposed 

(best)1

# of Individuals Exposed 

(max)1

Approx. % Regional 

Population (best)2

California sea lion 

(Zalophus californianus) N.A. N.A. N.A. 

Steller sea lion 

(Eumetopias jubatus) 1 N.A. <0.01 

Harbor seal 

(Phoca vitulina richardsi) 1 N.A. <0.01 

Northern elephant seal 

(Mirounga angustirostris) 5 52 <0.01 

N.A.—Data not available or species status was not assessed 

1 Best estimate and maximum estimate density are from Table 3 of SIO’s application. 2 Regional population size estimates are from Table 2 (above). 

Table 4 of SIO’s application shows the 

best and maximum estimates of the 

number of exposures and the number of 

individual marine mammals that 

potentially could be exposed to greater 

than or equal to 160 dB re 1 μPa (rms) 

during the different legs of the seismic 

survey if no animals move away from 

the survey vessel. 

The ‘‘best estimate’’ of the number of 

individual marine mammals that could 

be exposed to seismic sounds with 

received levels greater than or equal to 

160 dB re 1 μPa (rms) (but below Level 

A harassment thresholds) during the 

survey is shown in Table 4 of SIO’s 

application and Table 3 (shown above). 

The maximum estimates have been 

requested by SIO. The ‘‘best estimate’’ 

total includes 0 baleen whale 

individuals. These estimates were 

derived from the best density estimates 

calculated for these species in the area 

(see Table 4 of SIO’s application). In 

addition, 0 sperm whales (0 percent of 

the regional population) as well as 0 

beaked whales (0 percent of the regional 

population). Based on the best 

estimates, most (85.1 percent) of the 

marine mammals potentially exposed 

are dolphins and porpoises; shortbeaked common, Pacific white-sided, 

Northern right-whale, Risso’s dolphins 

and Dall’s porpoises are estimated to be 

the most common species in the area, 

with best estimates of 4 (<0.01 percent 

of the regional population), 6 (0.02 

percent), 5 (0.02 percent), 3 (0.03 

percent), and 39 (0.01 percent) exposed 

to greater or equal to 160 dB re μPa 

(rms) respectively. The remainder of the 

marine mammals that may be 

potentially exposed are pinnipeds; 

Northern fur, harbor, and Northern 

elephant seals, and Steller sea lions are 

estimated to be the most common 

species in the area, with best estimates 

of 3 (<0.01 percent), 1 (<0.01 percent), 

5 (<0.01 percent), and 1 (<0.01 percent) 

exposed to greater or equal to 160 dB re 

μPa (rms) respectively. Haul-outs of 

California sea lions and harbor seals are 

known to be located in the Newport, 

Oregon area. All of these numbers are 

considered small relative to the 

population sizes of the affected species 

or stocks. 

Potential Effects on Marine Mammal 

Habitat 

The proposed SIO seismic survey will 

not result in any permanent impact on 

habitats used by marine mammals, or to 

the food sources they use. The main 

impact issue associated with the 

proposed activity will be temporarily 

elevated noise levels and the associated 

direct effects on marine mammals, as 

described above. The following sections 

briefly review effects of airguns on fish 

and invertebrates, and more details are 

included in SIO’s application and EA. 

Potential Effects on Fish and 

Invertebrates 

One reason for the adoption of airguns 

as the standard energy source for marine 

seismic surveys is that, unlike 

explosives, they have not been 

associated with large-scale fish kills. 

However, existing information on the 

impacts of seismic surveys on marine 

fish populations is very limited (see 

Appendix B of SIO’s application). There 

are three types of potential effects on 

fish and invertebrates from exposure to 

seismic surveys: (1) pathological, (2) 

physiological, and (3) behavioral. 

Pathological effects involve lethal and 

temporary or permanent sub-lethal 

injury. Physiological effects involve 

temporary and permanent primary and 

secondary stress responses, such as 

changes in levels of enzymes and 

proteins. Behavioral effects refer to 

temporary and (if they occur) permanent 

changes in exhibited behavior (e.g., 

startle and avoidance behavior). The 

three categories are interrelated in 

complex ways. For example, it is 

possible that certain physiological and 

behavioral changes potentially could 

lead to an ultimate pathological effect 

on individuals (i.e., mortality). 

The specific received sound levels at 

which permanent adverse effects to fish 

potentially could occur are little studied 

and largely unknown. Furthermore, the 

available information on the impacts of 

seismic surveys on marine fish is from 

studies of individuals or portions of a 

population; there have been no studies 

at the population scale. Thus, available 

information provides limited insight on 

possible real-world effects at the ocean 

or population scale. This makes drawing 

conclusions about impacts on fish 

problematic because ultimately, the 

most important aspect of potential 

impacts relates to how exposure to 

seismic survey sound affects marine fish 

populations and their viability, 

including their availability to fisheries. 

The following sections provide a 

general synopsis of available 

information on the effects of exposure to 

seismic and other anthropogenic sound 

as relevant to fish. The information 

comprises results from scientific studies 

of varying degrees of rigor plus some 

anecdotal information. Some of the data 

sources may have serious shortcomings 

Federal Register / Vol. 74, No. 99 / Tuesday, May 26, 2009 / Notices 24815 

in methods, analysis, interpretation, and 

reproducibility that must be considered 

when interpreting their results (see 

Hastings and Popper, 2005). Potential 

adverse effects of the program’s sound 

sources on marine fish are then noted. 

Pathological Effects – The potential 

for pathological damage to hearing 

structures in fish depends on the energy 

level of the received sound and the 

physiology and hearing capability of the 

species in question (see Appendix B of 

SIO’s application). For a given sound to 

result in hearing loss, the sound must 

exceed, by some specific amount, the 

hearing threshold of the fish for that 

sound (Popper, 2005). The 

consequences of temporary or 

permanent hearing loss in individual 

fish on a fish population is unknown; 

however, it likely depends on the 

number of individuals affected and 

whether critical behaviors involving 

sound (e.g., predator avoidance, prey 

capture, orientation and navigation, 

reproduction, etc.) are adversely 

affected. 

Little is known about the mechanisms 

and characteristics of damage to fish 

that may be inflicted by exposure to 

seismic survey sounds. Few data have 

been presented in the peer-reviewed 

scientific literature. As far as we know, 

there are only two valid papers with 

proper experimental methods, controls, 

and careful pathological investigation 

implicating sounds produced by actual 

seismic survey airguns with adverse 

anatomical effects. One such study 

indicated anatomical damage and the 

second indicated TTS in fish hearing. 

The anatomical case is McCauley et al. 

(2003), who found that exposure to 

airgun sound caused observable 

anatomical damage to the auditory 

maculae of pink snapper (Pagrus 

auratus). This damage in the ears had 

not been repaired in fish sacrificed and 

examined almost two months after 

exposure. On the other hand, Popper et 

al. (2005) documented only TTS (as 

determined by auditory brainstem 

response) in two of three fish species 

from the Mackenzie River Delta. This 

study found that broad whitefish 

(Coreogonus nasus) that received a 

sound exposure level of 177 dB re 1 

μPa2.s showed no hearing loss. During 

both studies, the repetitive exposure to 

sound was greater than would have 

occurred during a typical seismic 

survey. However, the substantial lowfrequency energy produced by the 

airgun arrays [less than approximately 

400 Hz in the study by McCauley et al. 

(2003) and less than approximately 200 

Hz in Popper et al. (2005)] likely did not 

propagate to the fish because the water 

in the study areas was very shallow 

(approximately 9 m in the former case 

and less than 2 m in the latter). Water 

depth sets a lower limit on the lowest 

sound frequency that will propagate (the 

‘‘cutoff frequency’’) at about one-quarter 

wavelength (Urick, 1983; Rogers and 

Cox, 1988). 

Wardle et al. (2001) suggested that in 

water, acute injury and death of 

organisms exposed to seismic energy 

depends primarily on two features of 

the sound source: (1) the received peak 

pressure, and (2) the time required for 

the pressure to rise and decay. 

Generally, as received pressure 

increases, the period for the pressure to 

rise and decay decreases, and the 

chance of acute pathological effects 

increases. According to Buchanan et al. 

(2004), for the types of seismic airguns 

and arrays involved with the proposed 

program, the pathological (mortality) 

zone for fish and invertebrates would be 

expected to be within a few meters of 

the seismic source. Numerous other 

studies provide examples of no fish 

mortality upon exposure to seismic 

sources (Falk and Lawrence, 1973; 

Holliday et al., 1987; La Bella et al., 

1996; Santulli et al., 1999; McCauley et 

al., 2000a,b, 2003; Bjarti, 2002; Hassel et 

al., 2003; Popper et al., 2005). 

Some studies have reported, some 

equivocally, that mortality of fish, fish 

eggs, or larvae can occur close to 

seismic sources (Kostyuchenko, 1973; 

Dalen and Knutsen, 1986; Booman et 

al., 1996; Dalen et al., 1996). Some of 

the reports claimed seismic effects from 

treatments quite different from actual 

seismic survey sounds or even 

reasonable surrogates. Saetre and Ona 

(1996) applied a ’worst-case scenario’ 

mathematical model to investigate the 

effects of seismic energy on fish eggs 

and larvae. They concluded that 

mortality rates caused by exposure to 

seismic surveys are so low, as compared 

to natural mortality rates, that the 

impact of seismic surveying on 

recruitment to a fish stock must be 

regarded as insignificant. 

Physiological Effects – Physiological 

effects refer to cellular and/or 

biochemical responses of fish to 

acoustic stress. Such stress potentially 

could affect fish populations by 

increasing mortality or reducing 

reproductive success. Primary and 

secondary stress responses of fish after 

exposure to seismic survey sound 

appear to be temporary in all studies 

done to date (Sverdrup et al., 1994; 

McCauley et al., 2000a, 2000b). The 

periods necessary for the biochemical 

changes to return to normal are variable, 

and depend on numerous aspects of the 

biology of the species and of the sound 

stimulus (see Appendix B of SIO’s 

application). 

Summary of Physical (Pathological 

and Physiological) Effects – As 

indicated in the preceding general 

discussion, there is a relative lack of 

knowledge about the potential physical 

(pathological and physiological) effects 

of seismic energy on marine fish and 

invertebrates. Available data suggest 

that there may be physical impacts on 

egg, larval, juvenile, and adult stages at 

very close range. Considering typical 

source levels associated with 

commercial seismic arrays, close 

proximity to the source would result in 

exposure to very high energy levels. 

Whereas egg and larval stages are not 

able to escape such exposures, juveniles 

and adults most likely would avoid it. 

In the case of eggs and larvae, it is likely 

that the numbers adversely affected by 

such exposure would not be that 

different from those succumbing to 

natural mortality. Limited data 

regarding physiological impacts on fish 

and invertebrates indicate that these 

impacts are short term and are most 

apparent after exposure at close range. 

The proposed seismic program for 

2009 is predicted to have negligible to 

low physical effects on the various stags 

of fish and invertebrates for its relatively 

short duration (approximately 7 days) 

and unique survey lines extent. 

Therefore, physical effects of the 

proposed program on fish and 

invertebrates would not be significant. 

Behavioral Effects – Behavioral effects 

include changes in the distribution, 

migration, mating, and catchability of 

fish populations. Studies investigating 

the possible effects of sound (including 

seismic survey sound) on fish behavior 

have been conducted on both uncaged 

and caged individuals (Chapman and 

Hawkins, 1969; Pearson et al., 1992; 

Santulli et al., 1999; Wardle et al., 2001; 

Hassel et al., 2003). Typically, in these 

studies fish exhibited a sharp ‘‘startle’’ 

response at the onset of a sound 

followed by habituation and a return to 

normal behavior after the sound ceased. 

The existing body of information on 

the impacts of seismic survey sound on 

marine invertebrates is very limited. 

However, there is some unpublished 

and very limited evidence of the 

potential for adverse effects on 

invertebrates, thereby justifying further 

discussion and analysis of this issue. 

The three types of potential effects of 

exposure to seismic surveys on marine 

invertebrates are pathological, 

physiological, and behavioral. Based on 

the physical structure of their sensory 

organs, marine invertebrates appear to 

be specialized to respond to particle 

displacement components of an 

24816 Federal Register / Vol. 74, No. 99 / Tuesday, May 26, 2009 / Notices 

impinging sound field and not to the 

pressure component (Popper et al., 

2001; see Appendix C of SIO’s 

application). 

The only information available on the 

impacts of seismic surveys on marine 

invertebrates involves studies of 

individuals; there have been no studies 

at the population scale. Thus, available 

information provides limited insight on 

possible real-world effects at the 

regional or ocean scale. The most 

important aspect of potential impacts 

concerns how exposure to seismic 

survey sound ultimately affects 

invertebrate populations and their 

viability, including availability to 

fisheries. 

The following sections provide a 

synopsis of available information on the 

effects of exposure to seismic survey 

sound on species of decapod 

crustaceans and cephalopods, the two 

taxonomic groups of invertebrates on 

which most such studies have been 

conducted. The available information is 

from studies with variable degrees of 

scientific soundness and from anecdotal 

information. A more detailed review of 

the literature on the effects of seismic 

survey sound on invertebrates is 

provided in Appendix C of SIO’s 

application. 

Pathological Effects – In water, lethal 

and sub-lethal injury to organisms 

exposed to seismic survey sound could 

depend on at least two features of the 

sound source: (1) the received peak 

pressure, and (2) the time required for 

the pressure to rise and decay. 

Generally, as received pressure 

increases, the period for the pressure to 

rise and decay decreases, and the 

chance of acute pathological effects 

increases. For the single GI gun planned 

for the proposed program, the 

pathological (mortality) zone for 

crustaceans and cephalopods is 

expected to be within a few meters of 

the seismic source; however, very few 

specific data are available on levels of 

seismic signals that might damage these 

animals. This premise is based on the 

peak pressure and rise/decay time 

characteristics of seismic airgun arrays 

currently in use around the world. 

Some studies have suggested that 

seismic survey sound has a limited 

pathological impact on early 

developmental stages of crustaceans 

(Pearson et al., 1994; Christian et al., 

2003; DFO, 2004). However, the impacts 

appear to be either temporary or 

insignificant compared to what occurs 

under natural conditions. Controlled 

field experiments on adult crustaceans 

(Christian et al., 2003, 2004; DFO, 2004) 

and adult cephalopods (McCauley et al., 

2000a,b) exposed to seismic survey 

sound have not resulted in any 

significant pathological impacts on the 

animals. It has been suggested that 

exposure to commercial seismic survey 

activities has injured giant squid 

(Guerra et al., 2004), but there is no 

evidence to support such claims. 

Physiological Effects – Physiological 

effects refer mainly to biochemical 

responses by marine invertebrates to 

acoustic stress. Such stress potentially 

could affect invertebrate populations by 

increasing mortality or reducing 

reproductive success. Any primary and 

secondary stress responses (i.e., changes 

in haemolymph levels of enzymes, 

proteins, etc.) of crustaceans after 

exposure to seismic survey sounds 

appear to be temporary (hours to days) 

in studies done to date (J. Payne, DFO, 

pers. comm.). The periods necessary for 

these biochemical changes to return to 

normal are variable and depend on 

numerous aspects of the biology of the 

species and of the sound stimulus. 

Behavioral Effects – There is 

increasing interest in assessing the 

possible direct and indirect effects of 

seismic and other sounds on 

invertebrate behavior, particularly in 

relation to the consequences for 

fisheries. Change in behavior could 

potentially affect such aspects as 

reproductive success, distribution, 

susceptibility to predation, and 

catchability by fisheries. Studies 

investigating the possible behavioral 

effect of exposure to seismic survey 

sound on crustaceans and cephalopods 

have been conducted on both uncaged 

and caged animals. In some cases, 

invertebrates exhibiting startle 

responses (e.g., squid in McCauley et al., 

2000a,b). In other cases, no behavioral 

impacts were noted (e.g., crustaceans in 

Christian et al., 2003, 2004; DFO, 2004). 

There have been anecdotal reports of 

reduced catch rates of shrimp shortly 

after exposure to seismic surveys; 

however, other studies have not 

observed any significant changes in 

shrimp and catch rate (AndriguiettoFilho et al., 2005). Any adverse effects 

on crustacean and cephalopod behavior 

or fisheries attributable to seismic 

survey sound depend on the species in 

question and the nature of the fishery 

(season, duration, fishing method). 

Because of the reasons noted above 

and the nature of the proposed 

activities, the proposed operations are 

not expected to cause significant 

impacts on habitats that could cause 

significant or long-term consequences 

for individual marine mammals or their 

populations or stocks. Similarly, any 

effects to food sources are expected to 

be negligible. 

Subsistence Activities 

There is no subsistence hunting for 

marine mammals in the waters off of the 

coast of Oregon that implicates MMPA 

Section 101(a)(5)(D). 

Proposed Mitigation and Monitoring 

Mitigation and monitoring measures 

proposed to be implemented for the 

proposed seismic survey have been 

developed and refined during previous 

SIO and NSF-funded seismic studies 

and associated environmental 

assessments (EAs), IHA applications, 

and IHAs. The mitigation and 

monitoring measures described herein 

represent a combination of procedures 

required by past IHAs for other similar 

projects and on recommended best 

practices in Richardson et al. (1995), 

Pierson et al. (1998), and Weir and 

Dolman (2007). The measures are 

described in detail below. 

Mitigation measures that will be 

adopted during the proposed survey 

include: 

(1) Speed or course alteration, 

provided that doing so will not 

compromise operational safety 

requirements; 

(2) GI airgun shut-down procedures; 

and 

(3) Special procedures for situations 

or species of particular concern, e.g., 

emergency shut-down procedures if a 

North Pacific right whale and 

minimization of approaches to slopes, if 

possible, to avoid beaked whale habitat. 

Two other common mitigation 

measures, airgun array power-down and 

airgun array ramp-up, are not possible 

because only one, low-volume GI airgun 

will be used for the surveys. The 

thresholds for estimating Level A 

harassment take are also used in 

connection with proposed mitigation. 

Vessel-based Visual Monitoring 

Marine Mammal Visual Observers 

(MMVOs) will be based aboard the 

seismic source vessel and will watch for 

marine mammals near the vessel during 

daytime airgun operations and during 

start-ups of airguns at night. MMVOs 

will also watch for marine mammals 

near the seismic vessel for at least 30 

minutes prior to the start of airgun 

operations and after an extended shutdown of the airguns. When feasible 

MMVOs will also make observations 

during daytime periods when the 

seismic system is not operating for 

comparison of sighting rates and animal 

behavior with vs. without airgun 

operations. Based on MMVO 

observations, the GI airgun will be shutdown (see below) when marine 

mammals are detected within or about 

Federal Register / Vol. 74, No. 99 / Tuesday, May 26, 2009 / Notices 24817 

to enter a designated EZ that 

corresponds to the 180 or 190 dB re 1 

μPa (rms) isopleths, depending on 

whether the animal is a cetacean or 

pinniped . The MMVOs will continue to 

maintain watch to determine when the 

animal(s) are outside the EZ, and airgun 

operations will not resume until the 

animal has left that EZ. The predicted 

distances for the 180, and 190 dB EZs 

are listed according to the water depth 

in Table 1 above. 

During seismic operations off of the 

coast of Oregon, at least two MMVOs 

will be based aboard the Wecoma. 

MMVOs will be appointed by SIO with 

NMFS concurrence. At least one MMVO 

will monitor the EZ for marine 

mammals during ongoing daytime GI 

airgun operations and nighttime 

startups of the airguns. MMVO(s) will 

be on duty in shifts no longer than 4 

hours duration. The vessel crew will 

also be instructed to assist in detecting 

marine mammals and implementing 

mitigation measures (if practical). Before 

the start of the seismic survey the crew 

will be given additional instruction 

regarding how to do so. 

The Wecoma is a suitable platform for 

marine mammal observations. 

Observing stations will be on the bridge 

wings, with observers’ eyes 

approximately 6.5 m (21.3 ft) above the 

waterline and a 180 degree view 

outboard from either side, on the 

whaleback deck in front of the bridge, 

with observers eyes approximately 7 m 

(23 ft) above the waterline and 

approximately 200 degrees view 

forward, and on the aft control station, 

with observer’s eyes approximately 5.5 

m (18 ft) above the waterline and a 

approximately 180 degree view aft that 

includes the 40 m (131 ft) (180 dB) 

radius area around the GI airgun. The 

eyes of the bridge watch will be at a 

height of approximately 6.5 m; MMOs 

will repair to the enclosed bridge during 

any inclement weather. 

During the daytime, the MMVO(s) 

will scan the area around the vessel 

systematically with reticle binoculars 

(e.g., 7x50), Big-eye binoculars (25x150), 

optical range finders, and with the 

naked eye. During darkness, night 

vision devices will be available, when 

required. The MMVOs will be in 

wireless communication with ship’s 

officers on the bridge and scientists in 

the vessel’s operations laboratory, so 

they can advise promptly of the need for 

avoidance maneuvers or GI airgun shut 

down. 

Speed or Course Alteration – If a 

marine mammal is detected outside the 

EZ but is likely to enter based on its 

position and the relative movement of 

the vessel and animal, then if safety and 

scientific objectives allow, the vessel 

speed and/or course may be adjusted to 

minimize the likelihood of the animal 

entering the EZ. Typically, during 

seismic operations, major course and 

speed adjustments are often impractical 

when towing long seismic streamers and 

large source arrays, but are possible in 

this case because only one GI airgun and 

a short streamer will be used. 

Shut-down Procedures – The 

operating airguns(s) will be shut-down 

if a marine mammal is detected within 

or approaching the EZ for the single GI 

airgun source. Following a shut-down, 

GI airgun activity will not resume until 

the marine mammal is outside the EZ 

for the full array. The animal will be 

considered to have cleared the EZ if it: 

• Is visually observed to have left the 

EZ; 

• Has not been seen within the EZ for 

15 min in the case of species with 

shorter dive durations - small 

odontocetes and pinnipeds; and 

• Has not been seen within the EZ for 

30 min in the case of species with 

longer dive durations - mysticetes and 

large odontocetes, including sperm, 

pygmy sperm, dwarf sperm, killer, and 

beaked whales. 

Procedures for Situations or Species 

of Particular Concern – Special 

mitigation procedures will be used for 

these species of particular concern as 

follows: 

(1) The GI airgun will be shut-down 

if a North Pacific right whale is sighted 

at any distance from the vessel; 

(2) To avoid beaked whale habitat, 

approach to slopes will be minimized, 

if possible, during the proposed survey. 

Avoidance of airgun operations over or 

near submarine canyons has become a 

standard mitigation measure, but there 

are none within or near the study area. 

Four of the 16 OBS locations are on the 

continental slope, but the GI airgun is 

low volume and it will operate only for 

a short time (approximately 2 hours at 

each location). 

SIO and NSF will coordinate the 

planned marine mammal monitoring 

program associated with the seismic 

survey off the coast of Oregon with 

applicable U.S. agencies (e.g., NMFS), 

and will comply with their 

requirements. 

Proposed Reporting 

MMVO Data and Documentation 

MMVOs will record data to estimate 

the numbers of marine mammals 

exposed to various received sound 

levels and to document apparent 

disturbance reactions or lack thereof. 

Data will be used to estimate numbers 

of animals potentially ’taken’ by 

harassment (as defined in the MMPA). 

They will also provide information 

needed to order a shutdown of the 

seismic source when a marine mammal 

or sea turtles is within or near the EZ. 

When a sighting is made, the 

following information about the sighting 

will be recorded: 

(1) Species, group size, and age/size/ 

sex categories (if determinable); 

behavior when first sighted and after 

initial sighting; heading (if consistent), 

bearing, and distance from seismic 

vessel; sighting cue; apparent reaction to 

the seismic source or vessel (e.g., none, 

avoidance, approach, paralleling, etc.); 

and behavioral pace. 

(2) Time, location, heading, speed, 

activity of the vessel, sea state, 

visibility, cloud cover, and sun glare. 

The data listed (time, location, etc.) 

will also be recorded at the start and 

end of each observation watch, and 

during a watch whenever there is a 

change in one or more of the variables. 

All observations, as well as 

information regarding seismic source 

shut-down, will be recorded in a 

standardized format. Data accuracy will 

be verified by the MMVOs at sea, and 

preliminary reports will be prepared 

during the field program and summaries 

forwarded to the operating institution’s 

shore facility and to NSF weekly or 

more frequently. MMVO observations 

will provide the following information: 

(1) The basis for decisions about 

shutting down airgun arrays. 

(2) Information needed to estimate the 

number of marine mammals potentially 

’taken by harassment.’ These data will 

be reported to NMFS. 

(3) Data on the occurrence, 

distribution, and activities of marine 

mammals in the area where the seismic 

study is conducted. 

(4) Data on the behavior and 

movement patterns of marine mammals 

seen at times with and without seismic 

activity. 

A report will be submitted to NMFS 

within 90 days after the end of the 

cruise. The report will describe the 

operations that were conducted and 

sightings of marine mammals near the 

operations. The report will be submitted 

to NMFS, providing full documentation 

of methods, results, and interpretation 

pertaining to all monitoring. The 90–day 

report will summarize the dates and 

locations of seismic operations, and all 

marine mammal sightings (dates, times, 

locations, activities, associated seismic 

survey activities). The report will also 

include estimates of the amount and 

nature of potential ‘‘take’’ of marine 

mammals by harassment or in other 

ways. 

24818 Federal Register / Vol. 74, No. 99 / Tuesday, May 26, 2009 / Notices 

All injured or dead marine mammals 

(regardless of cause) will be reported to 

NMFS as soon as practicable. The report 

should include species or description of 

animal, condition of animal, location, 

time first found, observed behaviors (if 

alive) and photo or video, if available. 

Endangered Species Act (ESA) 

Under Section 7 of the ESA, NSF has 

begun consultation with the NMFS, 

Office of Protected Resources, 

Endangered Species Division on this 

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 the IHA. 

National Environmental Policy Act 

(NEPA) 

NSF prepared a draft Environmental 

Assessment titled ‘‘Marine Seismic 

Survey in the Northeast Pacific, July 

2009.’’ NSF’s draft EA incorporates an 

‘‘Environmental Assessment (EA) of a 

Planned Low-Energy Marine Seismic 

Survey by the Scripps Institution of 

Oceanography in the Northeast Pacific 

Ocean, July 2009’’ prepared by LGL 

Limited, Environmental Research 

Associates, on behalf of NSF and SIO. 

NMFS will either adopt NSF’s EA or 

conduct a separate NEPA analysis, as 

necessary, prior to making a 

determination on the issuance of the 

IHA. 

Preliminary Determinations 

NMFS has preliminarily determined 

that the impact of conducting the lowenergy marine seismic survey in the 

Northeast Pacific Ocean may result, at 

worst, in a temporary modification in 

behavior (Level B harassment) of small 

numbers of marine mammals. Further, 

this activity is expected to result in a 

negligible impact on the affected species 

or stocks. The provision requiring that 

the activity not have an unmitigable 

impact on the availability of the affected 

species or stock for subsistence uses is 

not implicated for this proposed action. 

For reasons stated previously in this 

document, the negligible impact 

determination is supported by: 

(1) The likelihood that, given 

sufficient ‘‘notice’’ through relatively 

slow ship speed, marine mammals are 

expected to move away from a noise 

source that is annoying prior to its 

becoming potentially injurious; 

(2) The fact that cetaceans would have 

to be closer than 23 m (75 ft) in deep 

water, 35 m (115 ft) in intermediate 

depths, and 150 m (492 ft) in shallow 

water when the GI airgun is in use from 

the vessel to be exposed to levels of 

sound (180 dB) believed to have even a 

minimal chance of causing PTS; 

(3) The fact that pinnipeds would 

have to closer than 8 m (26 ft) in deep 

water, 12 m (39 ft) in intermediate 

depths, and 95 m (312 ft) in shallow 

water when the GI airgun is in use from 

the vessel to be exposed to levels of 

sound (190 dB) believed to have even a 

minimal chance of causing PTS; 

(4) The fact that marine mammals 

would have to be closer than 220 m (ft) 

in deep water, 330 m at intermediate 

depths, and 570 m (ft) in shallow water 

when the GI airgun is in use from the 

vessel to be exposed to levels of sound 

(160 dB) believed to have even a 

minimal chance at causing TTS; and 

(5) The likelihood that marine 

mammal detection ability by trained 

observers is high at that short distance 

from the vessel, enabling the 

implementation of shut-downs to avoid 

injury, serious injury, or mortality. As a 

result, no take by injury or death is 

anticipated, and the potential for 

temporary or permanent hearing 

impairment is very low and will be 

avoided through the incorporation of 

the proposed mitigation measures. 

While the number of marine 

mammals potentially incidentally 

harassed 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, less than one percent of any of 

the estimated population sizes, and has 

been mitigated to the lowest level 

practicable through incorporation of the 

measures mentioned previously in this 

document. 

Proposed Authorization 

As a result of these preliminary 

determinations, NMFS proposes to issue 

an IHA to SIO for conducting a lowenergy marine seismic survey in the 

Northeast Pacific Ocean in July, 2009, 

provided the previously mentioned 

mitigation, monitoring, and reporting 

requirements are incorporated. 

Dated: March 19, 2009. 

James H. Lecky, 

Director, Office of Protected Resources, 

National Marine Fisheries Service. 

[FR Doc. E9–12149 Filed 5–22–09; 8:45 am] 

BILLING CODE 3510–22–S 

DEPARTMENT OF COMMERCE 

National Oceanic and Atmospheric 

Administration 

RIN 0648–XP28 

Incidental Taking of Marine Mammals; 

Taking of Marine Mammals Incidental 

to the Explosive Removal of Offshore 

Structures in the Gulf of Mexico 

AGENCY: National Marine Fisheries 

Service (NMFS), National Oceanic and 

Atmospheric Administration (NOAA), 

Commerce. 

ACTION: Notice; issuance of letters of 

authorization. 

SUMMARY: In accordance with the 

Marine Mammal Protection Act 

(MMPA) and implementing regulations, 

notification is hereby given that NMFS 

has issued one-year Letters of 

Authorization (LOA) to take marine 

mammals incidental to the explosive 

removal of offshore oil and gas 

structures (EROS) in the Gulf of Mexico. 

DATES: These authorizations are 

effective from June 1, 2009 through May 

31, 2010. 

ADDRESSES: The application and LOAs 

are available for review by writing to P. 

Michael Payne, Chief, Permits, 

Conservation, and Education Division, 

Office of Protected Resources, National 

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

20910–3235 or by telephoning the 

contact listed here (see FOR FURTHER

INFORMATION CONTACT), or online at: 

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

incidental.htm. Documents cited in this 

notice may be viewed, by appointment, 

during regular business hours, at the 

aforementioned address. 

FOR FURTHER INFORMATION CONTACT: 

Howard Goldstein or Ken Hollingshead, 

Office of Protected Resources, NMFS, 

301–713–2289. 

SUPPLEMENTARY INFORMATION: Section 

101(a)(5)(A) of the MMPA (16 U.S.C. 

1361 et seq.) directs the NMFS to allow, 

upon request, the incidental, but not 

intentional, taking of small numbers of 

marine mammals by United States 

citizens who engage in a specified 

activity (other than commercial fishing) 

within a specified geographical region, 

if certain findings are made by NMFS 

and regulations are issued. Under the 

MMPA, the term ‘‘taking’’ means to 

harass, hunt, capture, or kill or to 

attempt to harass, hunt capture, or kill 

marine mammals. 

Authorization for incidental taking, in 

the form of annual LOAs, may be 

granted by NMFS for periods up to five 

years if NMFS finds, after notification