19242 Federal Register / Vol. 77, No. 62 / Friday, March 30, 2012 / Notices 

occurrence in the study area. Therefore, 

section 7 consultation under the ESA for 

NMFS’s proposed issuance of an MMPA 

authorization is not warranted. 

National Environmental Policy Act 

(NEPA) 

The Navy has prepared a Final 

Environmental Impact Statement (EIS) 

for the proposed SSTC training 

activities. The FEIS was released in 

January 2011 and it is available at 

http://www.silverstrandtraining

complexeis.com/EIS.aspx/. NMFS is a 

cooperating agency (as defined by the 

Council on Environmental Quality (40 

CFR 1501.6)) in the preparation of the 

EIS. NMFS has subsequently adopted 

the FEIS for the SSTC training activities. 

Dated: March 20, 2012. 

James H. Lecky, 

Director, Office of Protected Resources, 

National Marine Fisheries Service. 

[FR Doc. 2012–7593 Filed 3–29–12; 8:45 am] 

BILLING CODE 3510–22–P 

DEPARTMENT OF COMMERCE 

National Oceanic and Atmospheric 

Administration 

RIN 0648–XB048 

Takes of Marine Mammals Incidental to 

Specified Activities; Low-Energy 

Marine Geophysical Survey in the 

Central Pacific Ocean, May Through 

June, 2012 

AGENCY: National Marine Fisheries 

Service (NMFS), National Oceanic and 

Atmospheric Administration (NOAA), 

Commerce. 

ACTION: Notice; proposed Incidental 

Harassment Authorization; request for 

comments. 

SUMMARY: NMFS has received an 

application from Lamont-Doherty Earth 

Observatory (L-DEO), a part of Columbia 

University, for an Incidental Harassment 

Authorization (IHA) to take marine 

mammals, by harassment, incidental to 

conducting a low-energy marine 

geophysical survey in the central Pacific 

Ocean, May through June, 2012. 

Pursuant to the Marine Mammal 

Protection Act (MMPA), NMFS is 

requesting comments on its proposal to 

issue an IHA to L-DEO to incidentally 

harass, by Level B harassment only, 16 

species of marine mammals during the 

specified activity. 

DATES: Comments and information must 

be received no later than April 28, 2012. 

ADDRESSES: Comments on the 

application should be addressed to P. 

Michael Payne, Chief, Permits and 

Conservation Division, Office of 

Protected Resources, National Marine 

Fisheries Service, 1315 East-West 

Highway, Silver Spring, MD 20910. The 

mailbox address for providing email 

comments is ITP.Cody@noaa.gov. NMFS 

is not responsible for email comments 

sent to addresses other than the one 

provided here. Comments sent via 

email, including all attachments, must 

not exceed a 10-megabyte file size. 

All comments received are a part of 

the public record and will generally be 

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

permits/incidental.htm#applications 

without change. All Personal Identifying 

Information (for example, name, 

address, etc.) voluntarily submitted by 

the commenter may be publicly 

accessible. Do not submit confidential 

business information or otherwise 

sensitive or protected information. 

An electronic copy of the application 

containing a list of the references used 

in this document may be obtained by 

writing to the above address, 

telephoning the contact listed here (see 

FOR FURTHER INFORMATION CONTACT) or 

visiting the internet at: http:// 

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

incidental.htm#applications. 

The following associated documents 

are also available at the same internet 

address: The U.S. National Science 

Foundation’s (NSF) draft Environmental 

Assessment (EA) Pursuant To The 

National Environmental Policy Act 

(NEPA) and Executive Order 12114. The 

draft EA incorporates an 

‘‘Environmental Assessment of a Marine 

Geophysical Survey by the R/V Marcus 

G. Langseth in the central Pacific Ocean, 

May 2012,’’ prepared by LGL Ltd., 

Environmental Research Associates 

(LGL), on behalf of NSF. 

Documents cited in this notice may be 

viewed, by appointment, during regular 

business hours, at the aforementioned 

address. 

FOR FURTHER INFORMATION CONTACT: 

Jeannine Cody, Office of Protected 

Resources, NMFS, 301–427–8401. 

SUPPLEMENTARY INFORMATION: 

Background 

Section 101(a)(5)(D) of the Marine 

Mammal Protection Act of 1972, as 

amended (MMPA; 16 U.S.C. 1361 et 

seq.) directs the Secretary of Commerce 

(Secretary) to authorize, upon request, 

the incidental, but not intentional, 

taking of small numbers of marine 

mammals of a species or population 

stock, 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, if the taking is limited to 

harassment, NMFS provides a notice of 

a proposed authorization to the public 

for review. 

Authorization for the incidental 

taking of small numbers of marine 

mammals shall be granted if NMFS 

finds that the taking will have a 

negligible impact on the species or 

stock(s), and will not have an 

unmitigable adverse impact on the 

availability of the species or stock(s) for 

subsistence uses (where relevant). The 

authorization must set forth the 

permissible methods of taking, other 

means of effecting the least practicable 

adverse impact on the species or stock 

and its habitat, and requirements 

pertaining to the mitigation, monitoring 

and reporting of such takings. 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. 

Section 101(a)(5)(D) of the MMPA 

establishes a 45-day time limit for 

NMFS’s 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 public comment period, NMFS 

must either issue or deny the 

authorization. NMFS must publish a 

notice in the Federal Register within 30 

days of its determination to issue or 

deny the authorization. 

Except with respect to certain 

activities not pertinent here, the MMPA 

defines ‘‘harassment’’ as: ‘‘* * * any act 

of pursuit, torment, or annoyance which 

(i) has the potential to injure a marine 

mammal or marine mammal stock in the 

wild [Level A harassment]; or (ii) has 

the potential to disturb a marine 

mammal or marine mammal stock in the 

wild by causing disruption of behavioral 

patterns, including, but not limited to, 

migration, breathing, nursing, breeding, 

feeding, or sheltering [Level B 

harassment].’’ 

Summary of Request 

NMFS received an application on 

December 12, 2012, from L-DEO for the 

taking by harassment, of marine 

mammals, incidental to conducting a 

low-energy marine seismic survey in the 

central Pacific Ocean. Upon receipt of 

additional information, NMFS 

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Federal Register / Vol. 77, No. 62 / Friday, March 30, 2012 / Notices 19243 

determined the application complete 

and adequate on February 28, 2012. 

L-DEO, with research funding from 

the NSF, plans to conduct the survey 

from May 1 through May 26, 2012 

offshore the Line Islands in the central 

Pacific Ocean. L-DEO plans to use one 

source vessel, the R/V Marcus G. 

Langseth (Langseth), a seismic airgun 

array and a single hydrophone streamer 

to conduct the low-energy geophysical 

survey that will provide the data 

necessary to understand sedimentation 

patterns on the flanks of the Line 

Islands Ridge and to investigate how 

climate patterns have varied over time 

in the late Pleistocene period. In 

addition to the operations of the seismic 

airgun array and hydrophone streamer, 

L-DEO intends to operate a multibeam 

echosounder (MBES), a sub-bottom 

profiler (SBP), and an acoustic Doppler 

current profiler (ADCP) continuously 

throughout the survey except while on 

station for marine coring activities. 

Acoustic stimuli (i.e., increased 

underwater sound) generated during the 

operation of the seismic airgun array 

may have the potential to cause a shortterm behavioral disturbance for marine 

mammals in the survey area. This is the 

principal means of marine mammal 

taking associated with these activities 

and L-DEO has requested an 

authorization to take 16 species of 

marine mammals by Level B 

harassment. Take is not expected to 

result from the use of the MBES, SBP, 

ADCP, or during marine coring 

operations for reasons discussed in this 

notice. Also, NMFS does not expect take 

to result from collision with the 

Langseth because it is a single vessel 

moving at relatively slow speeds (4.6 

knots (kts); 8.5 kilometers (km) per hour 

(km/h); 5.3 miles (mi) per hour (mph)) 

during seismic acquisition within the 

survey, for a relatively short period of 

time (approximately 6 days). It is likely 

that any marine mammal would be able 

to avoid the vessel. 

Description of the Proposed Specified 

Activity 

L-DEO’s proposed seismic survey in 

the central Pacific Ocean (partly in the 

Exclusive Economic Zone (EEZ) of the 

Republic of Kiribati and partly in the 

U.S. EEZ) is scheduled to commence on 

May 1, 2012 and end on May 26, 2012. 

The Langseth would depart from 

Honolulu, Hawaii (HI) on May 1, 2012 

and transit to the survey area in the 

central Pacific Ocean, approximately 

1,800 km (1,118.4 mi) south of Hawaii. 

At the conclusion of the survey 

activities, the Langseth proposes to 

arrive in Honolulu, HI on May 26, 2012. 

Some minor deviation from these dates 

is possible, depending on logistics, 

weather conditions, and the need to 

repeat some lines if data quality is 

substandard. Therefore, NMFS proposes 

to issue an authorization that is effective 

from May 1, 2012 to June 11, 2012. 

The research program will involve 

one source vessel, the Langseth. 

Geophysical survey activities will 

involve conducting seismic surveys at 

six sites in the Line Islands to determine 

coring locations (see Figure 1 in LDEO’s application). L-DEO will select 

coring sites from undisturbed sediments 

where there is potential for higher-thannormal sedimentation rates. The 

resulting cores will provide data 

necessary to understand how important 

climate patterns such as the El Nin ̃ o/La 

Nin ̃ a-Southern Oscillation and position 

of the Intertropical Convergence Zone 

have varied in the late Pleistocene. LDEO plans to deploy a total of 15 piston 

cores, 30 gravity cores, and eight 

multicores during the cruise. The piston 

and gravity corers have maximum 

diameters of approximately 90 

centimeters (cm) (35 inches (in)) and 45 

cm (17 in), respectively. The multi-corer 

is an eight-legged, cone-shaped frame 

and a weighted inner frame that holds 

up to eight plastic core sampling tubes 

that are 80 cm (31.4 in) long and 

approximately 10 cm (3.9 in) in 

diameter. Considering these 

dimensions, the coring equipment has a 

very small footprint. 

For the seismic component of the 

research program, the Langseth will 

deploy an array of two, low-energy 

Sercel Generator Injector (GI) airguns as 

an energy source. The acoustic receiving 

system will consist of a 2-km-long (1.2 

mi) hydrophone streamer. As the 

airguns are towed along the survey 

lines, the hydrophone streamer will 

receive the returning acoustic signals 

and transfer the data to the on-board 

processing system. 

The proposed study (e.g., equipment 

testing, startup, line changes, repeat 

coverage of any areas, and equipment 

recovery) will require approximately six 

days to complete approximately 1,853 

square km (km2) (715.4 square mi (mi2)) 

of transect lines. The Langseth will 

conduct additional seismic operations 

in the survey area associated with turns, 

airgun testing, and repeat coverage of 

any areas where the initial data quality 

is sub-standard. L-DEO has added 25 

percent of transect lines (463.2 km2; 

178.8 mi2) for contingency operations 

for a total area of 2,316 km2 (894.2 mi2). 

L-DEO, the Langseth’s operator, will 

conduct all planned seismic data 

acquisition activities, with on-board 

assistance by the scientists who have 

proposed the study. The Principal 

Investigators for this survey are Drs. J. 

Lynch-Stieglitz (Georgia Institute of 

Technology) and P. Polissar (L-DEO). 

The vessel will be self-contained, and 

the crew will live aboard the vessel for 

the entire cruise. 

Description of the Specified Geographic 

Region 

L-DEO will conduct the proposed 

survey in international waters in the 

central Pacific Ocean. The study area 

will encompass an area in the Line 

Islands bounded by approximately 0.5– 

8 degrees (°) South by 156–162° West 

(see Figure 1 in L-DEO’s application). 

Water depths in the survey area range 

from approximately 1,100 to 5,000 m 

(0.68 to 3.1 mi). The proposed seismic 

survey will be conducted in the EEZ of 

the Republic of Kiribati and partly in 

the U.S. EEZ. On behalf of NSF and LDEO, the U.S. State Department will 

seek authorization for L-DEO to work in 

Kiribati’s EEZ. 

Vessel Specifications 

The Langseth, owned by NSF, is a 

seismic research vessel with a 

propulsion system designed to be as 

quiet as possible to avoid interference 

with the seismic signals emanating from 

the airgun array. The vessel, which has 

a length of 71.5 meters (m) (235 feet (ft)); 

a beam of 17.0 m (56 ft); a maximum 

draft of 5.9 m (19 ft); and a gross 

tonnage of 3,834 pounds, is powered by 

two 3,550 horsepower (hp) Bergen BRG– 

6 diesel engines which drive two 

propellers. Each propeller has four 

blades and the shaft typically rotates at 

600 or 750 revolutions per minute. The 

vessel also has an 800-hp bowthruster 

which is not used during seismic 

acquisition. The Langseth’s operation 

speed during seismic acquisition will be 

approximately 4.6 kts (8.5 km/h; 5.3 

mph) and the cruising speed of the 

vessel outside of seismic operations is 

typically 18.5 km/h (11.5 mph or 10 

kts). 

The Langseth will tow a pair of 45- to 

105-in3 Sercel GI airguns, as well as the 

2-km-long hydrophone streamer, along 

predetermined lines (see Figure 1 in LDEO’s application). 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 (6 km; 3.7 mi). 

Thus, the vessel is more maneuverable 

during operations. 

The vessel also has an observation 

tower from which protected species 

visual observers (PSVO) will watch for 

marine mammals before and during the 

proposed airgun operations. When 

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19244 Federal Register / Vol. 77, No. 62 / Friday, March 30, 2012 / Notices 

stationed on the observation platform, 

the PSVO’s eye level will be 

approximately 21.5 m (71 ft) above sea 

level providing the PSVO an 

unobstructed view around the entire 

vessel. 

Acoustic Source Specifications 

Seismic Airguns 

The Langseth will deploy and tow an 

array consisting of a pair of 45 to 105 

in3 Sercel GI airguns with a total volume 

of approximately 210 in3 at a tow depth 

of 3 m (9.8 ft). The dominant frequency 

components range from zero to 188 

Hertz (Hz). The array configuration 

consists of the Langseth towing the two 

GI airguns 8 m (26.2 ft) apart, side-byside, approximately 50 m (164 ft) 

behind the vessel. During the survey, 

each airgun will emit a pulse at 

approximately 12-second (s) intervals 

which corresponds to a shot interval of 

approximately 3.75 m (123 ft) at a speed 

of approximately 11 km/hr (5.9 kts; 6.8 

mph). 

The generator chamber of each GI 

airgun, the one responsible for 

introducing the sound pulse into the 

ocean, is either 45 in3 or 105 in3, 

depending on how it is configured. The 

injector chamber injects air into the 

previously-generated bubble to maintain 

its shape, and does not introduce more 

sound into the water. Depending on the 

configuration, the total effective volume 

will be 90 in3 or 210 in3. As a 

precautionary measure, L-DEO assumes 

that they will use the larger volume. 

Metrics Used in This Document 

This section includes a brief 

explanation of the sound measurements 

frequently used in the discussions of 

acoustic effects in this document. Sound 

pressure is the sound force per unit 

area, and is usually measured in 

micropascals (mPa), where 1 pascal (Pa) 

is the pressure resulting from a force of 

one newton exerted over an area of one 

square meter. Sound pressure level 

(SPL) is expressed as the ratio of a 

measured sound pressure and a 

reference level. The commonly used 

reference pressure level in underwater 

acoustics is 1 mPa, and the units for 

SPLs are dB re: 1 mPa. SPL (in decibels 

(dB)) = 20 log (pressure/reference 

pressure). 

SPL is an instantaneous measurement 

and can be expressed as the peak, the 

peak-peak (p-p), or the root mean square 

(rms). Root mean square, which is the 

square root of the arithmetic average of 

the squared instantaneous pressure 

values, is typically used in discussions 

of the effects of sounds on vertebrates 

and all references to SPL in this 

document refer to the root mean square 

unless otherwise noted. SPL does not 

take the duration of a sound into 

account. 

Characteristics of the Airgun Pulses 

Airguns function by venting highpressure air into the water which creates 

an air bubble. The pressure signature of 

an individual airgun consists of a sharp 

rise and then fall in pressure, followed 

by several positive and negative 

pressure excursions caused by the 

oscillation of the resulting air bubble. 

The oscillation of the air bubble 

transmits sounds downward through the 

seafloor and the amount of sound 

transmitted in the near horizontal 

directions is reduced. However, the 

airgun array also emits sounds that 

travel horizontally toward non-target 

areas. 

The nominal source levels of the 

airgun array used by L-DEO on the 

Langseth is 239 dB re: 1 mPa(p-p) and the 

rms value for a given airgun pulse is 

typically 16 dB re: 1 mPa lower than the 

peak-to-peak value (Greene, 1997; 

McCauley et al., 1998, 2000a). However, 

the difference between rms and peak-topeak values for a given pulse depends 

on the frequency content and duration 

of the pulse, among other factors. 

NSF’s EA provides a detailed 

description of L-DEO’s modeling for 

marine seismic source arrays for species 

mitigation as well as the characteristics 

of the airgun pulses in Appendix A. 

These are the nominal source levels 

applicable to downward propagation. 

The effective source levels for 

horizontal propagation are lower than 

those for downward propagation 

because of the directional nature of the 

sound from the airguns. NMFS refers 

the reviewers to the IHA application 

and EA documents for additional 

information. 

Predicted Sound Levels for the Airguns 

L-DEO has modeled the received 

sound levels for the paired 105 in3 GI 

airgun configuration, in relation to 

distance and direction from the airguns 

(see Figure 2 of L-DEO’s application). 

The model does not allow for bottom 

interactions, and thus is most directly 

applicable to deep water. 

Tolstoy et al. (2004, 2009) reported 

results for propagation measurements of 

pulses from the Langseth’s 6-, 10-, 

12-, 20-, and 36-airgun arrays and 2 GI 

airguns in shallow- (approximately 50 m 

(164 ft)) and deep-water depths 

(approximately 1,600 m (5,249 ft)) in the 

Gulf of Mexico. However, Tolstoy et al. 

(2004) did not conduct measurements 

for the 2 GI airguns in deep water 

(greater than 1,000 m; 3,280 ft). Results 

of the Gulf of Mexico calibration studies 

showed that radii around the airguns for 

various received levels varied with 

water depth and that sound propagation 

varied with array tow depth. L-DEO 

used the results from the Gulf of Mexico 

study to determine the algorithm for its 

model that calculates the exclusion 

zones (EZ) for the two GI airguns. LDEO uses these values to designate 

mitigation zones and to estimate take 

(described in greater detail in Section 

VII of L-DEO’s application and Section 

IV of NSF’s EA) for marine mammals. 

Comparison of the Tolstoy et al. 

(2009) calibration study with L-DEO’s 

model for the Langseth’s 6-, 10-, 12-, 20- 

airgun arrays indicated that the model 

represents the actual received levels, 

within the first few kilometers, where 

the predicted EZs are located. However, 

the model for deep water (greater than 

1,000 m; 3,280 ft) overestimated the 

received sound levels at a given 

distance but is still valid for defining 

exclusion zones at various tow depths 

(Tolstoy et al., 2004). Because the 

calibration study did not conduct 

measurements for the 2 GI airgun array 

in deep water, L-DEO proposed to use 

the EZs predicted by L-DEO’s model for 

the proposed GI airgun operations in 

deep water as the EZs are likely 

conservative given the reported results 

for the other airgun arrays. 

Table 1 summarizes the predicted 

distances at which sound levels 

(160-,180-, and 190-dB re: 1 mPa) are 

expected to be received from the two GI 

airguns in deep water. To avoid the 

potential for injury, NMFS (1995, 2000) 

concluded that cetaceans should not be 

exposed to pulsed underwater noise at 

received levels exceeding 180 dB re: 1 

mPa. NMFS believes that to avoid the 

potential for permanent physiological 

damage (Level A harassment), cetaceans 

and pinnipeds should not be exposed to 

pulsed underwater noise at received 

levels exceeding 180 dB re: 1 mPa and 

190 dB re: 1 mPa, respectively. The 180- 

dB and 190-dB levels are shutdown 

criteria applicable to cetaceans and 

pinnipeds, respectively as specified by 

NMFS (1995, 2000). L-DEO used these 

levels were used to establish the EZs. If 

marine mammals are detected within or 

about to enter the appropriate EZ, LDEO will shut-down the airguns 

immediately. NMFS also assumes that 

marine mammals exposed to levels 

exceeding 160 dB re: 1 mPa (rms) may 

experience Level B harassment. 

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TABLE 1—DISTANCES TO WHICH SOUND LEVELS ≥ 160, 180, 190 DB RE: 1 μPA (RMS) COULD BE RECEIVED IN DEEP

WATER DURING THE PROPOSED SEISMIC SURVEY IN THE CENTRAL PACIFIC OCEAN, MAY, 2012 

[Distances Are Based on Model Results Provided by L-DEO] 

Source and volume Tow depth 

(m) 

Water depth 

(m) 

Predicted RMS radii distances (m) 

160 dB 180 dB 190 dB 

Two GI airguns (105 in3) .......................... 2 Deep (> 1,000 ) 670 70 20 

Multibeam Echosounder 

The Langseth will operate a 

Kongsberg EM 122 MBES concurrently 

during airgun operations to map 

characteristics of the ocean floor. The 

hull-mounted MBES emits brief pulses 

of sound (also called a ping) (10.5 to 13 

kilohertz (kHz)) in a fan-shaped beam 

that extends downward and to the sides 

of the ship. The transmitting beamwidth 

is one or two degrees (°) fore-aft and 

150° athwartship and the maximum 

source level is 242 dB re: 1 mPa. 

For deep-water operations, each ping 

consists of eight (in water greater than 

1,000 m; 3,280 ft) or four (less than 

1,000 m; 3,280 ft) successive, fanshaped transmissions, from two to 15 

milliseconds (ms) in duration and each 

ensonifying a sector that extends 1° foreaft. Continuous wave pulses increase 

from two to 15 milliseconds (ms) long 

in water depths up to 2,600 m (8,530 ft). 

The MBES uses frequency-modulated 

chirp pulses up to 100-ms long in water 

greater than 2,600 m (8,530 ft). The eight 

successive transmissions span an 

overall cross-track angular extent of 

about 150°, with 2-ms gaps between the 

pulses for successive sectors. 

Sub-bottom Profiler 

The Langseth will also operate a 

Knudsen Chirp 3260 SBP concurrently 

during airgun and MBES operations to 

provide information about the 

sedimentary features and bottom 

topography. The SBP is capable of 

reaching depths of 10,000 m (6.2 mi). 

The dominant frequency component of 

the SBP is 3.5 kHz which is directed 

downward in a 27ß cone by a hullmounted transducer on the vessel. The 

nominal power output is 10 kilowatts 

(kW), but the actual maximum radiated 

power is three kW or 222 dB re: 1 mPa. 

The ping duration is up to 64 ms with 

a pulse interval of one second, but a 

common mode of operation is to 

broadcast five pulses at 1-s intervals 

followed by a 5-s pause. 

Acoustic Doppler Current Profiler 

The Teledyne OS75 is an ADCP 

operating at a frequency of 75 kHz, 

producing a ping every 1.4 s. The 

system is a four-beam phased array with 

a beam angle of 30°. Each beam has a 

width of 4° and there is no overlap. 

Maximum output power is 1 kW with a 

maximum depth range of 700 m. 

NMFS expects that acoustic stimuli 

resulting from the proposed operation of 

the two GI airguns has the potential to 

harass marine mammals, incidental to 

the conduct of the proposed seismic 

survey. NMFS expects these 

disturbances to be temporary and result 

in a temporary modification in behavior 

and/or low-level physiological effects 

(Level B harassment only) of small 

numbers of certain species of marine 

mammals. NMFS does not expect that 

the movement of the Langseth, during 

the conduct of the seismic survey, has 

the potential to harass marine mammals 

because of the relatively slow operation 

speed of the vessel (4.6 kts; 8.5 km/hr; 

5.3 mph) during seismic acquisition. 

NMFS does not expect that the coring 

equipment, during the conduct of the 

seismic survey, has the potential to 

harass marine mammals because of the 

relatively small footprint and slow 

speed of the coring equipment. 

Description of the Marine Mammals in 

the Area of the Proposed Specified 

Activity 

Twenty-six marine mammal species 

may occur in the proposed survey area, 

including 19 odontocetes (toothed 

cetaceans), 6 mysticetes (baleen whales) 

and one species of pinniped during May 

through June. Six of these species are 

listed as endangered under the U.S. 

Endangered Species Act of 1973 (ESA; 

16 U.S.C. 1531 et seq.), including the 

blue (Balaenoptera musculus), fin 

(Balaenoptera physalus), humpback 

(Megaptera novaeangliae), sei 

(Balaenoptera borealis), and sperm 

(Physeter macrocephalus) whale and the 

Hawaiian monk seal (Monachus 

schauinslandi). 

Hawaiian monk seals have the 

potential to transit in the vicinity of the 

proposed seismic survey, although any 

occurrence would be rare as they are 

vagrants to the area. Based on available 

data, L-DEO does not expect to 

encounter Hawaiian monk seals within 

the proposed survey area and does not 

present analysis for these species. 

Accordingly, NMFS will not consider 

this pinniped species in greater detail 

and the proposed IHA will only address 

requested take authorizations for 

mysticetes and odontocetes. 

The species of marine mammals 

expected to be most common in the 

survey area (all odontocetes) include the 

pantropical spotted dolphin (Stenella 

attenuata), spinner dolphin (Stenella 

longirostris), and short-finned pilot 

whale (Globicephala macrorhynchus). 

The NMFS’ Southwest Fisheries 

Science Center (SWFSC) conducted the 

only cetacean distribution studies in the 

survey area. The Pacific Island Cetacean 

and Ecosystem Assessment Survey 

(PICEAS), conducted during July 

through November 2005, estimated the 

abundance of cetaceans in the U.S. EEZs 

of Palmyra Atoll, Kingman Reef, 

Johnston Atoll, and surrounding waters 

south of Hawaii (Barlow et al., 2008). 

The Hawaiian Island Cetacean 

Ecosystem Assessment Survey 

(HICEAS), conducted in the EEZ of the 

Hawaiian Islands, approximately 1,400 

km north of the survey area in 2002, 

estimated the abundance and 

distribution of cetaceans within the area 

using visual and acoustic methods 

(Barlow et al., 2004). 

Several other studies of marine 

mammal distribution and abundance 

have occurred in the wider eastern 

tropical Pacific Ocean. The most 

extensive regional distribution and 

abundance data come primarily from 

multi-year vessel surveys conducted by 

NMFS’ SWFSC. Researchers conducted 

the surveys during July to December in 

an area generally extending from 30° 

North to 18° South from the coastline to 

153° West (Wade and Gerrodette, 1993; 

Ferguson and Barlow, 2001; Gerrodette 

et al., 2008; and Jackson et al., 2008). 

The western boundary of the survey 

area is ∼350 km east of the proposed 

seismic survey area. Acoustic detections 

of cetaceans were also reported during 

summer/fall shipboard surveys in the 

eastern and central Pacific Ocean 

(Rankin et al. 2008). 

Table 2 presents information on the 

abundance, distribution, and 

conservation status of the marine 

mammals that may occur in the 

proposed survey area in May, 2012. 

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TABLE 2—HABITAT, ABUNDANCE, AND CONSERVATION STATUS OF MARINE MAMMALS THAT MAY OCCUR IN OR NEAR THE

PROPOSED SEISMIC SURVEY AREA IN THE CENTRAL PACIFIC OCEAN

[See text and Tables 2 and 3 in L-DEO’s application and environmental analysis for further details] 

Species 

Occurrence in 

survey area 

during May 

Habitat Abundance 

in the EPT 1 ESA2 Density 3

Mysticetes: 

Humpback whale ....................... Rare .................... Mainly nearshore waters and banks 4 20,800; 36,600 EN 0 

Bryde’s whale ............................ Common ............. Pelagic, coastal ................................ 5 9,000 NL 0 .58 

Sei whale ................................... Rare .................... Mostly pelagic .................................. 6 10,422 EN 0 

Fin whale ................................... Rare .................... Slope, pelagic ................................... 7 7260–12,620 EN 0 

Blue whale ................................. Rare .................... Pelagic, coastal ................................ 8 13,620–18,680 EN 0 .01 

Minke whale .............................. Rare .................... Coastal ............................................. 9 1,400 NL 0 

Odontocetes: 

Sperm whale ............................. Common ............. Pelagic, steep topography ............... 10 26,053 EN 2 .97 

Pygmy sperm whale .................. Uncommon .......... Deep waters off shelf ....................... N.A. NL 0 .03 

Dwarf sperm whale ................... Common ............. Deep, shelf, slope ............................ 11 11,200 NL 7 .65 

Blainville’s beaked whale .......... Uncommon .......... Pelagic .............................................. 9 20,000 NL 0 .35 

Cuvier’s beaked whale .............. Common ............. Slope, pelagic ................................... 12 291 NL 6 .66 

Ginkgo-toothed beaked whale .. Rare .................... Pelagic .............................................. 13 25,300 NL 0 .35 

Longman’s beaked whale ......... Uncommon .......... Pelagic .............................................. 13 25,300 NL 0 .44 

Rough-toothed dolphin .............. Common ............. Mainly pelagic .................................. 107,633 NL 1 .24 

Bottlenose dolphin ..................... Common ............. Coastal, shelf, deep ......................... 335,834 NL 4 .94 

Pantropical spotted dolphin ....... Common ............. Coastal and pelagic ......................... 14 439,208 NL 120 .4 

Spinner dolphin ......................... Common ............. Coastal and pelagic ......................... 15 1,797,716 NL 183 .5 

Striped dolphin .......................... Common ............. Off continental shelf ......................... 964,362 NL 16 .45 

Fraser’s dolphin ......................... Common ............. Pelagic .............................................. 9 289,300 NL 4 .47 

Risso’s dolphin .......................... Common ............. Shelf, slope, seamounts ................... 110,457 NL 0 .81 

Melon-headed whale ................. Common ............. Pelagic .............................................. 9 45,400 NL 1 .29 

Pygmy killer whale .................... Uncommon .......... Pelagic, coastal ................................ 9 38,900 NL 0 

False killer whale ...................... Common ............. Pelagic .............................................. 16 1,329; 9 39,800 NL 0 .10 

Killer whale ................................ Rare .................... Widely distributed ............................. 17 8,500 NL 0 .15 

Short-finned pilot whale ............ Common ............. Pelagic, high-relief ............................ 6 589,315 NL 5 .07 

N.A. Not available or not assessed. 

1Abundance from Gerrodette et al. (2008) unless otherwise indicated. 2 U.S. Endangered Species Act: EN = Endangered, T = Threatened, NL = Not listed. 

3 Density (#/1000 km2) estimates as listed in Table 3 of the application. Cetacean densities are based on NMFS SWFSC ETP ship transect 

surveys conducted in 1986–2006 from predictive modeling (Barlow et al., 2009; Read et al., 2009) or in 2002 from Barlow (2006). Densities are 

corrected for f(0) and g(0). Where no source is given, the species was not included in Read et al. (2009) or Barlow (2006). 4 North Pacific (Barlow et al. 2009a) and Southern Hemisphere (Reilly et al. 2008). 5 North Pacific (Wada 1976). 

6Gerrodette and Forcada (2002). 

7 North Pacific (Tillman 1977). 

8Ohsumi and Wada (1974). 

9Wade and Gerrodette (1993). 

10Whitehead (2002). 11Estimate mostly for K. sima but may also include K. breviceps (Wade and Gerrodette 1993). 12Ferguson and Barlow (2003). 13This estimate includes all species of the genus Mesoplodon (Wade and Gerrodette 1993). 14For the western/southern offshore spotted dolphin. 15For the whitebelly and the eastern spinner dolphin stocks (Gerrodette et al. 2008). 16Palmyra stock (Barlow and Rankin 2007). 17Ford (2009). 

NMFS refers the reader to Sections III 

and IV of L-DEO’s application for 

detailed information regarding the 

abundance and distribution, population 

status, and life history and behavior of 

these species and their occurrence in 

the proposed project area. The 

application also presents how L-DEO 

calculated the estimated densities for 

the marine mammals in the proposed 

survey area. NMFS has reviewed these 

data and determined them to be the best 

available scientific information for the 

purposes of the proposed IHA. 

Potential Effects on Marine Mammals 

Acoustic stimuli generated by the 

operation of the airguns, which 

introduce sound into the marine 

environment, may have the potential to 

cause Level B harassment of marine 

mammals in the proposed survey area. 

The effects of sounds from airgun 

operations might include one or more of 

the following: Tolerance, masking of 

natural sounds, behavioral disturbance, 

temporary or permanent impairment, or 

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). Although the 

possibility cannot be entirely excluded, 

it is unlikely that the proposed project 

would result in any cases of temporary 

or permanent hearing impairment, or 

any significant non-auditory physical or 

physiological effects. Based on the 

available data and studies described 

here, some behavioral disturbance is 

expected, but NMFS expects the 

disturbance to be localized and shortterm. 

Tolerance to Sound 

Studies on marine mammals’ 

tolerance to sound in the natural 

environment are relatively rare. 

Richardson et al. (1995) defines 

tolerance as the occurrence of marine 

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mammals in areas where they are 

exposed to human activities or manmade noise. In many cases, tolerance 

develops by the animal habituating to 

the stimulus (i.e., the gradual waning of 

responses to a repeated or ongoing 

stimulus) (Richardson, et al., 1995; 

Thorpe, 1963), but because of ecological 

or physiological requirements, many 

marine animals may need to remain in 

areas where they are exposed to chronic 

stimuli (Richardson, et al., 1995). 

Numerous studies have shown that 

pulsed sounds from airguns are often 

readily detectable in the water at 

distances of many kilometers. Malme et 

al., (1985) studied the responses of 

humpback whales on their summer 

feeding grounds in southeast Alaska to 

seismic pulses from a airgun with a total 

volume of 100-in3. They noted that the 

whales did not exhibit persistent 

avoidance when exposed to the airgun 

and concluded that there was no clear 

evidence of avoidance, despite the 

possibility of subtle effects, at received 

levels up to 172 dB: re 1 mPa. 

Weir (2008) observed marine mammal 

responses to seismic pulses from a 24- 

airgun array firing a total volume of 

either 5,085 in3 or 3,147 in3 in Angolan 

waters between August 2004 and May 

2005. She recorded a total of 207 

sightings of humpback whales (n=66), 

sperm whales (n=124), and Atlantic 

spotted dolphins (n=17) and reported 

that there were no significant 

differences in encounter rates 

(sightings/hr) for humpback and sperm 

whales according to the airgun array’s 

operational status (i.e., active versus 

silent). 

Masking of Natural Sounds 

The term masking refers to the 

inability of a subject to recognize the 

occurrence of an acoustic stimulus as a 

result of the interference of another 

acoustic stimulus (Clark et al., 2009). 

Introduced underwater sound may, 

through masking, reduce the effective 

communication distance of a marine 

mammal species if the frequency of the 

source is close to that used as a signal 

by the marine mammal, and if the 

anthropogenic sound is present for a 

significant fraction of the time 

(Richardson et al., 1995). 

Masking effects of pulsed sounds 

(even from large arrays of airguns) on 

marine mammal calls and other natural 

sounds are expected to be limited. 

Because of the intermittent nature and 

low duty cycle of seismic airgun pulses, 

animals can emit and receive sounds in 

the relatively quiet intervals between 

pulses. However, in some situations, 

reverberation occurs for much or the 

entire interval between pulses (e.g., 

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, and their calls can 

usually be heard between the seismic 

pulses (e.g., 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; and 

Dunn and Hernandez, 2009). However, 

Clark and Gagnon (2006) reported that 

fin whales in the northeast Pacific 

Ocean went silent for an extended 

period starting soon after the onset of a 

seismic survey in the area. Similarly, 

there has been one report that sperm 

whales ceased calling when exposed to 

pulses from a very distant seismic ship 

(Bowles et al., 1994). However, more 

recent studies found that they continued 

calling in the presence of seismic pulses 

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

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

and Jochens et al., 2008). Dolphins and 

porpoises commonly are heard calling 

while airguns are operating (e.g., 

Gordon et al., 2004; Smultea et al., 2004; 

Holst et al., 2005a, b; and Potter et al., 

2007). The sounds important to small 

odontocetes are predominantly at much 

higher frequencies than are the 

dominant components of airgun sounds, 

thus limiting the potential for masking. 

In general, NMFS expects the masking 

effects of seismic pulses to be minor, 

given the normally intermittent nature 

of seismic pulses. Refer to Appendix 

A(4) of L-DEO’s environmental analysis 

for a more detailed discussion of 

masking effects on marine mammals. 

Behavioral Disturbance 

Disturbance includes a variety of 

effects, including subtle to conspicuous 

changes in behavior, movement, 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 (Richardson et al., 

1995; Wartzok et al., 2004; Southall et 

al., 2007; Weilgart, 2007). If a marine 

mammal does react briefly to an 

underwater sound by changing its 

behavior or moving a small distance, the 

impacts of the change are unlikely to be 

significant to the individual, let alone 

the stock or population. However, if a 

sound source displaces marine 

mammals from an important feeding or 

breeding area for a prolonged period, 

impacts on individuals and populations 

could be significant (e.g., Lusseau and 

Bejder, 2007; Weilgart, 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 would be present within a 

particular distance of industrial 

activities and/or exposed to a particular 

level of industrial sound. In most cases, 

this approach likely overestimates the 

numbers of marine mammals that would 

be affected in some biologicallyimportant manner. 

The sound criteria used to estimate 

how many marine mammals might be 

disturbed to some biologicallyimportant degree by a seismic program 

are based primarily on behavioral 

observations of a few species. Scientists 

have conducted detailed studies on 

humpback, gray, bowhead (Balaena 

mysticetus), and sperm whales. Less 

detailed data are available for some 

other species of baleen whales, small 

toothed whales, and sea otters (Enhydra 

lutris), but for many species there are no 

data on responses to marine seismic 

surveys. 

Baleen Whales—Baleen whales 

generally tend to avoid operating 

airguns, but avoidance radii are quite 

variable (reviewed in Richardson, et al., 

1995). 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 (5.1) of L-DEO’s 

environmental analysis, baleen whales 

exposed to strong noise pulses from 

airguns often react by deviating from 

their normal migration route and/or 

interrupting their feeding and moving 

away. In the cases of migrating gray and 

bowhead whales, the observed changes 

in behavior appeared to be of little or no 

biological consequence to the animals 

(Richardson et al., 1995). 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 shown that 

seismic pulses with received levels of 

160 to 170 dB re: 1 mPa seem to cause 

obvious avoidance behavior in a 

substantial fraction of the animals 

exposed (Malme et al., 1986, 1988; 

Richardson et al., 1995). In many areas, 

seismic pulses from large arrays of 

airguns diminish to those levels at 

distances ranging from four to 15 km 

from the source. A substantial 

proportion of the baleen whales within 

those distances may show avoidance or 

other strong behavioral reactions to the 

airgun array. Subtle behavioral changes 

sometimes become evident at somewhat 

lower received levels, and studies 

summarized in Appendix A(5) of NSF’s 

EA have shown that some species of 

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baleen whales, notably bowhead and 

humpback whales, at times show strong 

avoidance at received levels lower than 

160–170 dB re: 1 mPa. 

Researchers have studied the 

responses of humpback whales to 

seismic surveys during migration, 

feeding during the summer months, 

breeding while offshore from Angola, 

and wintering offshore from Brazil. 

McCauley et al. (1998, 2000a) studied 

the responses of humpback whales off 

western Australia to a full-scale seismic 

survey with a 16-airgun array (2,678-in3) 

and to a single, 20-in3 airgun with 

source level of 227 dB re: 1 mPa (p-p). 

In the 1998 study, the researchers 

documented that avoidance reactions 

began at five to eight km (3.1 to 4.9 mi) 

from the array, and that those reactions 

kept most pods approximately three to 

four km (1.9 to 2.5 mi) from the 

operating seismic boat. In the 2000 

study, McCauley et al. noted localized 

displacement during migration of four 

to five km (2.5 to 3.1 mi) by traveling 

pods and seven to 12 km (4.3 to 7.5 mi) 

by more sensitive resting pods of cowcalf pairs. Avoidance distances with 

respect to the single airgun were smaller 

but consistent with the results from the 

full array in terms of the received sound 

levels. The mean received level for 

initial avoidance of an approaching 

airgun was 140 dB re: 1 mPa for 

humpback pods containing females, and 

at the mean closest point of approach 

distance, the received level was 143 dB 

re: 1 mPa. The initial avoidance response 

generally occurred at distances of five to 

eight km (3.1 to 4.9 mi) from the airgun 

array and two 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 mPa. 

Data collected by observers during 

several seismic surveys in the northwest 

Atlantic Ocean showed that sighting 

rates of humpback whales were 

significantly greater during non-seismic 

periods compared with periods when a 

full array was operating (Moulton and 

Holst, 2010). In addition, humpback 

whales were more likely to swim away 

and less likely to swim towards a vessel 

during seismic versus non-seismic 

periods (Moulton and Holst, 2010). 

Humpback whales on their summer 

feeding grounds in Frederick Sound and 

Stephens Passage, 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 to 169 dB re: 1 

mPa. 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 mPa. 

Other studies have suggested that 

south Atlantic humpback whales 

wintering off Brazil may be displaced or 

even strand upon exposure to seismic 

surveys (Engel et al., 2004). Although, 

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 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, 2007: 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 their 

activity (migrating versus 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 to 30 km (12.4 to 

18.6 mi) from a medium-sized airgun 

source at received sound levels of 

approximately 120 to 130 dB re: 1 mPa 

(Miller et al., 1999; Richardson et al., 

1999; see Appendix A(5) of NSF’s EA). 

However, more recent research on 

bowhead whales (Miller et al., 2005; 

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 surfacing– 

respiration–dive cycles were evident 

upon statistical analysis (Richardson et 

al., 1986). In the summer, bowheads 

typically begin to show avoidance 

reactions at received levels of about 152 

to 178 dB re: 1 mPa (Richardson et al., 

1986, 1995; Ljungblad et al., 1988; 

Miller et al., 2005). 

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. They estimated, 

based on small sample sizes, that 50 

percent of feeding gray whales stopped 

feeding at an average received pressure 

level of 173 dB re: 1 mPa on an 

(approximate) rms basis, and that 10 

percent of feeding whales interrupted 

feeding at received levels of 163 dB re: 

1 mPa. 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 western Pacific gray whales 

feeding off Sakhalin Island, Russia 

(Wursig et al., 1999; 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). 

Various species of Balaenoptera (blue, 

sei, fin, and minke whales) have 

occasionally been seen in areas 

ensonified by airgun pulses (Stone, 

2003; MacLean and Haley, 2004; Stone 

and Tasker, 2006), and calls from blue 

and fin whales have been localized in 

areas with airgun operations (e.g., 

McDonald et al., 1995; Dunn and 

Hernandez, 2009; Castellote et al., 

2010). Sightings by observers on seismic 

vessels off the United Kingdom from 

1997 to 2000 suggest that, during times 

of good sightability, sighting rates for 

mysticetes (mainly fin and sei whales) 

were similar when large arrays of 

airguns were shooting vs. silent (Stone, 

2003; Stone and Tasker, 2006). 

However, these whales tended to exhibit 

localized avoidance, remaining 

significantly further (on average) from 

the airgun array during seismic 

operations compared with non-seismic 

periods (Stone and Tasker, 2006). 

Castellote et al. (2010) also observed 

localized avoidance by fin whales 

during seismic airgun events in the 

western Mediterranean Sea and adjacent 

Atlantic waters from 2006–2009. They 

reported that singing fin whales moved 

away from an operating airgun array for 

a time period that extended beyond the 

duration of the airgun activity. 

Ship-based monitoring studies of 

baleen whales (including blue, fin, sei, 

minke, and whales) in the northwest 

Atlantic found that overall, this group 

had lower sighting rates during seismic 

versus non-seismic periods (Moulton 

and Holst, 2010). Baleen whales as a 

group were also seen significantly 

farther from the vessel during seismic 

compared with non-seismic periods, 

and they were more often seen to be 

swimming away from the operating 

seismic vessel (Moulton and Holst, 

2010). Blue and minke whales were 

initially sighted significantly farther 

from the vessel during seismic 

operations compared to non-seismic 

periods; the same trend was observed 

for fin whales (Moulton and Holst, 

2010). Minke whales were most often 

observed to be swimming away from the 

vessel when seismic operations were 

underway (Moulton and Holst, 2010). 

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Data on short-term reactions by 

cetaceans to impulsive noises are not 

necessarily indicative of long-term or 

biologically significant effects. It is not 

known whether impulsive sounds affect 

reproductive rate or distribution and 

habitat use in subsequent days or years. 

However, gray whales have 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 (Appendix A in 

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

1995; Allen and Angliss, 2011). The 

western Pacific gray whale population 

did not seem affected by a seismic 

survey in its feeding ground during a 

previous year (Johnson et al., 2007). 

Similarly, bowhead whales have 

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; Allen and 

Agliss, 2011). 

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 earlier and (in more detail) 

in Appendix B of NSF’s EA have been 

reported for toothed whales. However, 

there are recent systematic studies on 

sperm whales (e.g., Gordon et al., 2006; 

Madsen et al., 2006; Winsor and Mate, 

2006; Jochens et al., 2008; Miller et al., 

2009). There is an increasing amount of 

information about responses of various 

odontocetes to seismic surveys based on 

monitoring studies (e.g., 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; Hauser et al., 

2008; Holst and Smultea, 2008; Weir, 

2008; Barkaszi et al., 2009; Richardson 

et al., 2009; Moulton and Holst, 2010). 

Seismic operators and protected 

species observers (PSOs) on seismic 

vessels regularly see dolphins and other 

small toothed whales near operating 

airgun arrays, but in general there is a 

tendency for most delphinids to show 

some avoidance of operating seismic 

vessels (e.g., Goold, 1996a,b,c; 

Calambokidis and Osmek, 1998; Stone, 

2003; Moulton and Miller, 2005; Holst 

et al., 2006; Stone and Tasker, 2006; 

Weir, 2008; Richardson et al., 2009; 

Barkaszi et al., 2009; Moulton and 

Holst, 2010). 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 

arrays of airguns are firing (e.g., 

Moulton and Miller, 2005). Nonetheless, 

small toothed whales more often 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 (e.g., Stone and Tasker, 

2006; Weir, 2008, Barry et al., 2010; 

Moulton and Holst, 2010). In most 

cases, the avoidance radii for delphinids 

appear to be small, on the order of one 

km or less, and some individuals show 

no apparent avoidance. The beluga 

whale (Delphinapterus leucas) is a 

species that (at least at times) shows 

long-distance avoidance of seismic 

vessels. Summer aerial surveys 

conducted in the southeastern Beaufort 

Sea reported that sighting rates of beluga 

whales were significantly lower at 

distances of 10 to 20 km (6.2 to 12.4 mi) 

from an operating airgun array 

compared to distances of 20 to 30 km 

(12.4 to 18.6 mi). Further, PSOs on 

seismic boats in that area have rarely 

reported sighting beluga whales (Miller 

et al., 2005; Harris et al., 2007). 

Captive bottlenose dolphins (Tursiops 

truncatus) 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). However, the animals 

tolerated high received levels of sound 

before exhibiting aversive behaviors. 

Results for porpoises depend on 

species. The limited available data 

suggest that harbor porpoises (Phocoena 

phocoena) show stronger avoidance of 

seismic operations than do Dall’s 

porpoises (Stone, 2003; MacLean and 

Koski, 2005; Bain and Williams, 2006; 

Stone and Tasker, 2006). Dall’s 

porpoises seem relatively tolerant of 

airgun operations (MacLean and Koski, 

2005; Bain and Williams, 2006), 

although they too have been observed to 

avoid large arrays of operating airguns 

(Calambokidis and Osmek, 1998; Bain 

and Williams, 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 

(Richardson et al., 1995; Southall et al., 

2007). 

Most studies of sperm whales exposed 

to airgun sounds indicate that the sperm 

whale shows considerable tolerance of 

airgun pulses (e.g., Stone, 2003; 

Moulton et al., 2005, 2006a; Stone and 

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

the whales do not show strong 

avoidance, and they continue to call 

(see Appendix B of NSF’s EA for 

review). However, controlled exposure 

experiments in the Gulf of Mexico 

indicate that foraging behavior was 

altered upon exposure to airgun sound 

(Jochens et al., 2008; Miller et al., 2009; 

Tyack, 2009). 

There are almost no specific data on 

the behavioral reactions of beaked 

whales to seismic surveys. However, 

some northern bottlenose whales 

(Hyperoodon ampullatus) remained in 

the general area and continued to 

produce high-frequency clicks when 

exposed to sound pulses from distant 

seismic surveys (Gosselin and Lawson, 

2004; Laurinolli and Cochrane, 2005; 

Simard et al., 2005). Most beaked 

whales tend to avoid approaching 

vessels of other types (e.g., Wursig et al., 

1998). They may also dive for an 

extended period when approached by a 

vessel (e.g., 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 quite long (Baird et al., 2006; 

Tyack et al., 2006). Based on a single 

observation, Aguilar-Soto et al. (2006) 

suggested that foraging efficiency of 

Cuvier’s beaked whales (Ziphius 

cavirostris) may be reduced by close 

approach of vessels. In any event, it is 

likely that most beaked whales would 

also show strong avoidance of an 

approaching seismic vessel, although 

this has not been documented 

explicitly. In fact, Moulton and Holst 

(2010) reported 15 sightings of beaked 

whales during seismic studies in the 

Northwest Atlantic; seven of those 

sightings were made at times when at 

least one airgun was operating. There 

was little evidence to indicate that 

beaked whale behavior was affected by 

airgun operations; sighting rates and 

distances were similar during seismic 

and non-seismic periods (Moulton and 

Holst, 2010). 

There are increasing indications that 

some beaked whales tend to strand 

when naval exercises involving midfrequency sonar operation are ongoing 

nearby (e.g., Simmonds and LopezJurado, 1991; Frantzis, 1998; NOAA and 

USN, 2001; Jepson et al., 2003; 

Hildebrand, 2005; Barlow and Gisiner, 

2006; see also the Stranding and 

Mortality section in this notice). These 

strandings are apparently a disturbance 

response, although auditory or other 

injuries or other physiological effects 

may also be involved. Whether beaked 

whales would ever react similarly to 

seismic surveys is unknown. Seismic 

survey sounds are quite different from 

those of the sonar in operation during 

the above-cited incidents. 

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 

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porpoises (See Appendix A of NSF’s 

EA). 

Pinnipeds—Pinnipeds are not likely 

to show a strong avoidance reaction to 

the airgun array. Visual monitoring from 

seismic vessels has shown only slight (if 

any) avoidance of airguns by pinnipeds, 

and only slight (if any) changes in 

behavior, see Appendix B(5) of NSF’s 

EA. In the Beaufort Sea, some ringed 

seals avoided an area of 100 m (328 ft) 

to (at most) a few hundred meters 

around seismic vessels, but many seals 

remained within 100 to 200 m (328 to 

656 ft) of the trackline as the operating 

airgun array passed by (e.g., Harris et al., 

2001; Moulton and Lawson, 2002; 

Miller et al., 2005). Ringed seal sightings 

averaged somewhat farther away from 

the seismic vessel when the airguns 

were operating than when they were 

not, but the difference was small 

(Moulton and Lawson, 2002). Similarly, 

in Puget Sound, sighting distances for 

harbor seals and California sea lions 

tended to be larger when airguns were 

operating (Calambokidis and Osmek, 

1998). Previous telemetry work suggests 

that avoidance and other behavioral 

reactions may be stronger than evident 

to date from visual studies (Thompson 

et al., 1998). 

Hearing Impairment and Other Physical 

Effects 

Exposure to high intensity sound for 

a sufficient duration may result in 

auditory effects such as a noise-induced 

threshold shift—an increase in the 

auditory threshold after exposure to 

noise (Finneran et al., 2005). Factors 

that influence the amount of threshold 

shift include the amplitude, duration, 

frequency content, temporal pattern, 

and energy distribution of noise 

exposure. The magnitude of hearing 

threshold shift normally decreases over 

time following cessation of the noise 

exposure. The amount of threshold shift 

just after exposure is called the initial 

threshold shift. If the threshold shift 

eventually returns to zero (i.e., the 

threshold returns to the pre-exposure 

value), it is called temporary threshold 

shift (TTS) (Southall et al., 2007). 

Researchers have studied TTS in 

certain captive odontocetes and 

pinnipeds exposed to strong sounds 

(reviewed in Southall et al., 2007). 

However, there has been no specific 

documentation of TTS let alone 

permanent hearing damage, i.e., 

permanent threshold shift (PTS), in freeranging marine mammals exposed to 

sequences of airgun pulses during 

realistic field conditions. 

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). Table 1 (introduced earlier in 

this document) presents the distances 

from the Langseth’s airguns at which the 

received energy level (per pulse, flatweighted) would be expected to be 

greater than or equal to 180 dB re: 1 mPa. 

To avoid the potential for injury, 

NMFS (1995, 2000) concluded that 

cetaceans should not be exposed to 

pulsed underwater noise at received 

levels exceeding 180 dB re: 1 mPa. 

NMFS believes that to avoid the 

potential for permanent physiological 

damage (Level A harassment), cetaceans 

should not be exposed to pulsed 

underwater noise at received levels 

exceeding 180 dB re: 1 mPa. The 180-dB 

level is a shutdown criterion applicable 

to cetaceans, as specified by NMFS 

(2000); these levels were used to 

establish the EZs. NMFS also assumes 

that cetaceans exposed to SPLs 

exceeding 160 dB re: 1 mPa may 

experience Level B harassment. 

Researchers have derived TTS 

information for odontocetes from 

studies on the bottlenose dolphin and 

beluga. For the one harbor porpoise 

tested, the received level of airgun 

sound that elicited onset of TTS was 

lower (Lucke et al., 2009). If these 

results from a single animal are 

representative, it is inappropriate to 

assume that onset of TTS occurs at 

similar received levels in all 

odontocetes (cf. Southall et al., 2007). 

Some cetaceans apparently can incur 

TTS at considerably lower sound 

exposures than are necessary to elicit 

TTS in the beluga or bottlenose dolphin. 

For baleen whales, there are no data, 

direct or indirect, on levels or properties 

of sound that are required to induce 

TTS. The frequencies to which baleen 

whales are most sensitive are assumed 

to be lower than those to which 

odontocetes are most sensitive, 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) 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 (Southall et al., 2007). For this 

proposed study, L-DEO expects no cases 

of TTS given the low abundance of 

baleen whales in the planned study area 

at the time of the survey, and the strong 

likelihood that baleen whales would 

avoid the approaching airguns (or 

vessel) before being exposed to levels 

high enough for TTS to occur. 

In pinnipeds, TTS thresholds 

associated with exposure to brief pulses 

(single or multiple) of underwater sound 

have not been measured. Initial 

evidence from more prolonged 

(nonpulse) exposures suggested that 

some pinnipeds (harbor seals in 

particular) incur TTS at somewhat 

lower received levels than do small 

odontocetes exposed for similar 

durations (Kastak et al., 1999, 2005; 

Ketten et al., 2001). The indirectly 

estimated TTS threshold for pulsed 

sounds would be approximately 181 to 

186 dB re: 1 mPa (Southall et al., 2007), 

or a series of pulses for which the 

highest SEL 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). 

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, whereas 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 at least mild 

TTS, there has been further speculation 

about the possibility that some 

individuals occurring very close to 

airguns might incur PTS (e.g., 

Richardson et al., 1995, p. 372ff; 

Gedamke et al., 2008). Single or 

occasional occurrences of mild TTS are 

not indicative of permanent auditory 

damage, but repeated or (in some cases) 

single exposures to a level well above 

that causing TTS onset might elicit PTS. 

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 

dBs above that inducing mild TTS if the 

animal were exposed to strong sound 

pulses with rapid rise times—see 

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Appendix A(6) of NSF’s EA. 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 greater than six dB 

(Southall et al., 2007). 

Given the higher level of sound 

necessary to cause PTS as compared 

with TTS, it is considerably less likely 

that PTS would occur. Baleen whales 

generally avoid the immediate area 

around operating seismic vessels, as do 

some other marine mammals. 

Stranding and Mortality 

When a live or dead marine mammal 

swims or floats onto shore and becomes 

‘‘beached’’ or incapable of returning to 

sea, the event is termed a ‘‘stranding’’ 

(Geraci et al., 1999; Perrin and Geraci, 

2002; Geraci and Lounsbury, 2005; 

NMFS, 2007). The legal definition for a 

stranding under the MMPA is that ‘‘(A) 

a marine mammal is dead and is (i) on 

a beach or shore of the United States; or 

(ii) in waters under the jurisdiction of 

the United States (including any 

navigable waters); or (B) a marine 

mammal is alive and is (i) on a beach 

or shore of the United States and is 

unable to return to the water; (ii) on a 

beach or shore of the United States and, 

although able to return to the water, is 

in need of apparent medical attention; 

or (iii) in the waters under the 

jurisdiction of the United States 

(including any navigable waters), but is 

unable to return to its natural habitat 

under its own power or without 

assistance’’ (16 U.S.C. 1421h). 

Marine mammals are known to strand 

for a variety of reasons, such as 

infectious agents, biotoxicosis, 

starvation, fishery interaction, ship 

strike, unusual oceanographic or 

weather events, sound exposure, or 

combinations of these stressors 

sustained concurrently or in series. 

However, the cause or causes of most 

strandings are unknown (Geraci et al., 

1976; Eaton, 1979; Odell et al., 1980; 

Best, 1982). Numerous studies suggest 

that the physiology, behavior, habitat 

relationships, age, or condition of 

cetaceans may cause them to strand or 

might pre-dispose them to strand when 

exposed to another phenomenon. These 

suggestions are consistent with the 

conclusions of numerous other studies 

that have demonstrated that 

combinations of dissimilar stressors 

commonly combine to kill an animal or 

dramatically reduce its fitness, even 

though one exposure without the other 

does not produce the same result 

(Chroussos, 2000; Creel, 2005; DeVries 

et al., 2003; Fair and Becker, 2000; Foley 

et al., 2001; Moberg, 2000; Relyea, 

2005a; 2005b, Romero, 2004; Sih et al., 

2004). 

Strandings Associated with Military 

Active Sonar–Several sources have 

published lists of mass stranding events 

of cetaceans in an attempt to identify 

relationships between those stranding 

events and military active sonar 

(Hildebrand, 2004; IWC, 2005; Taylor et 

al., 2004). For example, based on a 

review of stranding records between 

1960 and 1995, the International 

Whaling Commission (2005) identified 

ten mass stranding events and 

concluded that, out of eight stranding 

events reported from the mid-1980s to 

the summer of 2003, seven had been 

coincident with the use of midfrequency active sonar and most 

involved beaked whales. 

Over the past 12 years, there have 

been five stranding events coincident 

with military MF active sonar use in 

which exposure to sonar is believed by 

NMFS and the Navy to have been a 

contributing factor to strandings: Greece 

(1996); the Bahamas (2000); Madeira 

(2000); Canary Islands (2002); and Spain 

(2006). NMFS refers the reader to Cox et 

al. (2006) for a summary of common 

features shared by the strandings events 

in Greece (1996), Bahamas (2000), 

Madeira (2000), and Canary Islands 

(2002); and Fernandez et al., (2005) for 

an additional summary of the Canary 

Islands 2002 stranding event. 

Potential for Stranding from Seismic 

Surveys—The association of strandings 

of beaked whales with naval exercises 

involving mid-frequency active sonar 

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 (e.g., 

Hildebrand, 2005; Southall et al., 2007). 

Appendix A(6) of NSF’s EA 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 hemorrhage or other forms 

of trauma; 

(3) A physiological change such as a 

vestibular response leading to a 

behavioral change or stress-induced 

hemorrhagic diathesis, leading in turn 

to tissue damage; and 

(4) Tissue damage directly from sound 

exposure, such as through acousticallymediated bubble formation and growth 

or acoustic resonance of tissues. Some 

of these mechanisms are unlikely to 

apply in the case of impulse sounds. 

However, there are increasing 

indications that gas-bubble disease 

(analogous to the bends), induced in 

supersaturated tissue by a behavioral 

response to acoustic exposure, could be 

a pathologic mechanism for the 

strandings and mortality of some deepdiving cetaceans exposed to sonar. 

However, 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 signals 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 impulses 

with most of the energy below one kHz. 

Typical military mid-frequency sonar 

emits non-impulse sounds at 

frequencies of two to 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 signals 

can, in special circumstances, lead (at 

least indirectly) to physical damage and 

mortality (e.g., Balcomb and Claridge, 

2001; NOAA and USN, 2001; Jepson et 

al., 2003; Ferna ́ndez et al., 2004, 2005; 

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) were not well founded (IAGC, 

2004; IWC, 2007). In September 2002, 

there was a stranding of two Cuvier’s 

beaked whales in the Gulf of California, 

Mexico, when the L-DEO vessel R/V 

Maurice Ewing was operating a 20- 

airgun (8,490 in3) array in the general 

area. The link between the stranding 

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and the seismic surveys 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 in 

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 likelihood that any beaked 

whales nearby would avoid the 

approaching vessel before being 

exposed to high sound levels; and 

(2) Differences between the sound 

sources operated by L-DEO and those 

involved in the naval exercises 

associated with strandings. 

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, and other types of organ or 

tissue damage (Cox et al., 2006; Southall 

et al., 2007). Studies examining such 

effects are limited. However, resonance 

effects (Gentry, 2002) and direct noiseinduced bubble formations (Crum et al., 

2005) are implausible in the case of 

exposure to an impulsive broadband 

source like an airgun array. If seismic 

surveys disrupt diving patterns of deepdiving 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 specific evidence of this 

upon exposure to airgun pulses. 

In general, very little is known about 

the potential for seismic survey sounds 

(or other types of strong underwater 

sounds) to cause non-auditory physical 

effects in marine mammals. Such 

effects, if they occur at all, would 

presumably be limited to short distances 

and to activities that extend over a 

prolonged period. The available data do 

not allow identification of a specific 

exposure level above which nonauditory 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 and some 

odontocetes, are especially unlikely to 

incur non-auditory physical effects. 

Potential Effects of Other Acoustic 

Devices 

Multibeam Echosounder 

L-DEO will operate the Kongsberg EM 

122 MBES from the source vessel during 

the planned study. Sounds from the 

MBES are very short pulses, occurring 

for 2 to 15 ms once every 5 to 20 s, 

depending on water depth. Most of the 

energy in the sound pulses emitted by 

this MBES is at frequencies near 12 kHz, 

and the maximum source level is 242 

dB re: 1 mPa. The beam is narrow (1 to 

2°) in fore-aft extent and wide (150°) in 

the cross-track extent. Each ping 

consists of eight (in water greater than 

1,000 m deep) or four (less than 1,000 

m deep) successive fan-shaped 

transmissions (segments) at different 

cross-track angles. Any given mammal 

at depth near the trackline would be in 

the main beam for only one or two of 

the segments. Also, marine mammals 

that encounter the Kongsberg EM 122 

are unlikely to be subjected to repeated 

pulses because of the narrow fore-aft 

width of the beam and will receive only 

limited amounts of pulse energy 

because of the short pulses. Animals 

close to the vessel (where the beam is 

narrowest) are especially unlikely to be 

ensonified for more than one 2- to 

15-ms pulse (or two pulses if in the 

overlap area). Similarly, Kremser et al. 

(2005) noted that the probability of a 

cetacean swimming through the area of 

exposure when an MBES emits a pulse 

is small. The animal would have to pass 

the transducer at close range and be 

swimming at speeds similar to the 

vessel in order to receive the multiple 

pulses that might result in sufficient 

exposure to cause TTS. 

Navy sonars that have been linked to 

avoidance reactions and stranding of 

cetaceans: (1) Generally have longer 

pulse duration than the Kongsberg EM 

122; and (2) are often directed close to 

horizontally versus more downward for 

the MBES. The area of possible 

influence of the MBES is much 

smaller—a narrow band below the 

source vessel. Also, the duration of 

exposure for a given marine mammal 

can be much longer for naval sonar. 

During L-DEO’s operations, the 

individual pulses will be very short, and 

a given mammal would not receive 

many of the downward-directed pulses 

as the vessel passes by. Possible effects 

of an MBES on marine mammals are 

outlined in this section. 

Masking—Marine mammal 

communications will not be masked 

appreciably by the MBES signals given 

the low duty cycle of the echosounder 

and the brief period when an individual 

mammal is likely to be within its beam. 

Furthermore, in the case of baleen 

whales, the MBES signals (12 kHz) do 

not overlap with the predominant 

frequencies in the calls, which would 

avoid any significant masking. 

Behavioral Responses—Behavioral 

reactions of free-ranging marine 

mammals to sonars, echosounders, and 

other sound sources appear to vary by 

species and circumstance. Observed 

reactions have included silencing and 

dispersal by sperm whales (Watkins et 

al., 1985), increased vocalizations and 

no dispersal by pilot whales 

(Globicephala melas) (Rendell and 

Gordon, 1999), and the previouslymentioned beachings by beaked whales. 

During exposure to a 21 to 25 kHz 

‘‘whale-finding’’ sonar with a source 

level of 215 dB re: 1 mPa, gray whales 

reacted by orienting slightly away from 

the source and being deflected from 

their course by approximately 200 m 

(Frankel, 2005). When a 38-kHz 

echosounder and a 150-kHz acoustic 

Doppler current profiler were 

transmitting during studies in the 

eastern Tropical Pacific Ocean, baleen 

whales showed no significant responses, 

while spotted and spinner dolphins 

were detected slightly more often and 

beaked whales less often during visual 

surveys (Gerrodette and Pettis, 2005). 

Captive bottlenose dolphins and a 

beluga whale exhibited changes in 

behavior when exposed to 1-s tonal 

signals at frequencies similar to those 

that will be emitted by the MBES used 

by L-DEO, and to shorter broadband 

pulsed signals. Behavioral changes 

typically involved what appeared to be 

deliberate attempts to avoid the sound 

exposure (Schlundt et al., 2000; 

Finneran et al., 2002; Finneran and 

Schlundt, 2004). The relevance of those 

data to free-ranging odontocetes is 

uncertain, and in any case, the test 

sounds were quite different in duration 

as compared with those from an MBES. 

Hearing Impairment and Other 

Physical Effects—Given recent stranding 

events that have been associated with 

the operation of naval sonar, there is 

concern that mid-frequency sonar 

sounds can cause serious impacts to 

marine mammals (see above this 

section). However, the MBES proposed 

for use by L-DEO is quite different than 

sonar used for navy operations. Pulse 

duration of the MBES is very short 

relative to the naval sonar. Also, at any 

given location, an individual marine 

mammal would be in the beam of the 

MBES for much less time given the 

generally downward orientation of the 

beam and its narrow fore-aft beamwidth; 

navy sonar often uses near-horizontallydirected sound. Those factors would all 

reduce the sound energy received from 

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the MBES rather drastically relative to 

that from naval sonar. 

Based upon the best available science, 

NMFS believes that the brief exposure 

of marine mammals to one pulse, or 

small numbers of signals, from the 

MBES is not likely to result in the 

harassment of marine mammals. 

Sub-Bottom Profiler 

L-DEO will also operate an SBP from 

the source vessel during the proposed 

survey. Sounds from the SBP are very 

short pulses, occurring for one to four 

ms once every second. Most of the 

energy in the sound pulses emitted by 

the SBP is at 3.5 kHz, and the beam is 

directed downward. The sub-bottom 

profiler on the Langseth has a maximum 

source level of 222 dB re: 1 mPa. 

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— 

even for an SBP more powerful than 

that on the Langseth—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. 

Masking—Marine mammal 

communications will not be masked 

appreciably by the SBP signals given the 

directionality of the signal and the brief 

period when an individual mammal is 

likely to be within its beam. 

Furthermore, in the case of most baleen 

whales, the SBP signals do not overlap 

with the predominant frequencies in the 

calls, which would avoid significant 

masking. 

Behavioral Responses—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. However, the pulsed signals from 

the SBP are considerably weaker than 

those from the MBES. Therefore, 

behavioral responses are not expected 

unless marine mammals are very close 

to the source. 

Hearing Impairment and Other 

Physical Effects—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 higher-power 

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. Based upon the best available 

science, NMFS believes that the brief 

exposure of marine mammals to signals 

from the SBP is not likely to result in 

the harassment of marine mammals. 

Potential Effects of Vessel Movement 

and Collisions 

Vessel movement in the vicinity of 

marine mammals has the potential to 

result in either a behavioral response or 

a direct physical interaction. Both 

scenarios are discussed below this 

section. 

Behavioral Responses to Vessel 

Movement 

There are limited data concerning 

marine mammal behavioral responses to 

vessel traffic and vessel noise, and a 

lack of consensus among scientists with 

respect to what these responses mean or 

whether they result in short-term or 

long-term adverse effects. In those cases 

where there is a busy shipping lane or 

where there is a large amount of vessel 

traffic, marine mammals may 

experience acoustic masking 

(Hildebrand, 2005) if they are present in 

the area (e.g., killer whales in Puget 

Sound; Foote et al., 2004; Holt et al., 

2008). In cases where vessels actively 

approach marine mammals (e.g., whale 

watching or dolphin watching boats), 

scientists have documented that animals 

exhibit altered behavior such as 

increased swimming speed, erratic 

movement, and active avoidance 

behavior (Bursk, 1983; Acevedo, 1991; 

Baker and MacGibbon, 1991; Trites and 

Bain, 2000; Williams et al., 2002; 

Constantine et al., 2003), reduced blow 

interval (Ritcher et al., 2003), disruption 

of normal social behaviors (Lusseau, 

2003; 2006), and the shift of behavioral 

activities which may increase energetic 

costs (Constantine et al., 2003; 2004)). A 

detailed review of marine mammal 

reactions to ships and boats is available 

in Richardson et al. (1995). For each of 

the marine mammal taxonomy groups, 

Richardson et al. (1995) provides the 

following assessment regarding 

reactions to vessel traffic: 

Toothed whales: ‘‘In summary, 

toothed whales sometimes show no 

avoidance reaction to vessels, or even 

approach them. However, avoidance can 

occur, especially in response to vessels 

of types used to chase or hunt the 

animals. This may cause temporary 

displacement, but we know of no clear 

evidence that toothed whales have 

abandoned significant parts of their 

range because of vessel traffic.’’ 

Baleen whales: ‘‘When baleen whales 

receive low-level sounds from distant or 

stationary vessels, the sounds often 

seem to be ignored. Some whales 

approach the sources of these sounds. 

When vessels approach whales slowly 

and non-aggressively, whales often 

exhibit slow and inconspicuous 

avoidance maneuvers. In response to 

strong or rapidly changing vessel noise, 

baleen whales often interrupt their 

normal behavior and swim rapidly 

away. Avoidance is especially strong 

when a boat heads directly toward the 

whale.’’ 

Behavioral responses to stimuli are 

complex and influenced to varying 

degrees by a number of factors, such as 

species, behavioral contexts, 

geographical regions, source 

characteristics (moving or stationary, 

speed, direction, etc.), prior experience 

of the animal and physical status of the 

animal. For example, studies have 

shown that beluga whales’ reactions 

varied when exposed to vessel noise 

and traffic. In some cases, naive beluga 

whales exhibited rapid swimming from 

ice-breaking vessels up to 80 km (49.7 

mi) away, and showed changes in 

surfacing, breathing, diving, and group 

composition in the Canadian high 

Arctic where vessel traffic is rare (Finley 

et al., 1990). In other cases, beluga 

whales were more tolerant of vessels, 

but responded differentially to certain 

vessels and operating characteristics by 

reducing their calling rates (especially 

older animals) in the St. Lawrence River 

where vessel traffic is common (Blane 

and Jaakson, 1994). In Bristol Bay, 

Alaska, beluga whales continued to feed 

when surrounded by fishing vessels and 

resisted dispersal even when 

purposefully harassed (Fish and Vania, 

1971). 

In reviewing more than 25 years of 

whale observation data, Watkins (1986) 

concluded that whale reactions to vessel 

traffic were ‘‘modified by their previous 

experience and current activity: 

Habituation often occurred rapidly, 

attention to other stimuli or 

preoccupation with other activities 

sometimes overcame their interest or 

wariness of stimuli.’’ Watkins noticed 

that over the years of exposure to ships 

in the Cape Cod area, minke whales 

changed from frequent positive interest 

(e.g., approaching vessels) to generally 

uninterested reactions; fin whales 

changed from mostly negative (e.g., 

avoidance) to uninterested reactions; 

right whales apparently continued the 

same variety of responses (negative, 

uninterested, and positive responses) 

with little change; and humpbacks 

dramatically changed from mixed 

responses that were often negative to 

reactions that were often strongly 

positive. Watkins (1986) summarized 

that ‘‘whales near shore, even in regions 

with low vessel traffic, generally have 

become less wary of boats and their 

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noises, and they have appeared to be 

less easily disturbed than previously. In 

particular locations with intense 

shipping and repeated approaches by 

boats (such as the whale-watching areas 

of Stellwagen Bank), more and more 

whales had positive reactions to familiar 

vessels, and they also occasionally 

approached other boats and yachts in 

the same ways.’’ 

Although the radiated sound from the 

Langseth will be audible to marine 

mammals over a large distance, it is 

unlikely that animals will respond 

behaviorally (in a manner that NMFS 

would consider MMPA harassment) to 

low-level distant shipping noise as the 

animals in the area are likely to be 

habituated to such noises (Nowacek et 

al., 2004). In light of these facts, NMFS 

does not expect the Langseth’s 

movements to result in Level B 

harassment. 

Vessel Strike 

Ship strikes of cetaceans can cause 

major wounds, which may lead to the 

death of the animal. An animal at the 

surface could be struck directly by a 

vessel, a surfacing animal could hit the 

bottom of a vessel, or an animal just 

below the surface could be cut by a 

vessel’s propeller. The severity of 

injuries typically depends on the size 

and speed of the vessel (Knowlton and 

Kraus, 2001; Laist et al., 2001; 

Vanderlaan and Taggart, 2007). 

The most vulnerable marine mammals 

are those that spend extended periods of 

time at the surface in order to restore 

oxygen levels within their tissues after 

deep dives (e.g., the sperm whale). In 

addition, some baleen whales, such as 

the North Atlantic right whale, seem 

generally unresponsive to vessel sound, 

making them more susceptible to vessel 

collisions (Nowacek et al., 2004). These 

species are primarily large, slow moving 

whales. Smaller marine mammals (e.g., 

bottlenose dolphin) move quickly 

through the water column and are often 

seen riding the bow wave of large ships. 

Marine mammal responses to vessels 

may include avoidance and changes in 

dive pattern (NRC, 2003). 

An examination of all known ship 

strikes from all shipping sources 

(civilian and military) indicates vessel 

speed is a principal factor in whether a 

vessel strike results in death (Knowlton 

and Kraus, 2001; Laist et al., 2001; 

Jensen and Silber, 2003; Vanderlaan and 

Taggart, 2007). In assessing records in 

which vessel speed was known, Laist et 

al. (2001) found a direct relationship 

between the occurrence of a whale 

strike and the speed of the vessel 

involved in the collision. The authors 

concluded that most deaths occurred 

when a vessel was traveling in excess of 

14.9 mph (24.1 km/hr;13 kts). 

L-DEO’s proposed operation of one 

vessel for the proposed survey is 

relatively small in scale compared to the 

number of commercial ships transiting 

at higher speeds in the same areas on an 

annual basis. The probability of vessel 

and marine mammal interactions 

occurring during the proposed survey is 

unlikely due to the Langseth’s slow 

operational speed, which is typically 4.6 

kts (8.5 km/h; 5.3 mph). Outside of 

operations, the Langseth’s cruising 

speed would be approximately 11.5 

mph (18.5 km/h; 10 kts) which is 

generally below the speed at which 

studies have noted reported increases of 

marine mammal injury or death (Laist et 

al., 2001). 

As a final point, the Langseth has a 

number of other advantages for avoiding 

ship strikes as compared to most 

commercial merchant vessels, including 

the following: The Langseth’s bridge 

offers good visibility to visually monitor 

for marine mammal presence; PSVOs 

posted during operations scan the ocean 

for marine mammals and must report 

visual alerts of marine mammal 

presence to crew; and the PSVOs 

receive extensive training that covers 

the fundamentals of visual observing for 

marine mammals and information about 

marine mammals and their 

identification at sea. 

Coring Activities 

None of the coring devices have an 

acoustic component. There would be no 

drilling or hammering associated with 

the coring devices as the coring devices 

would use gravity to penetrate the 

sediment. The Langseth crew would 

lower the coring devices slowly from 

the ship on a wire; the wire would be 

kept taught as a result of the weight of 

the corer equipment and gravity. Due to 

the anticipated taughtness of the wire, 

NMFS does not anticipate entanglement 

with the gear as it is deployed or 

retrieved from the vessel. Marine 

mammals would avoid the gear and 

avoid any potential strikes from the 

equipment. 

The potential effects to marine 

mammals described in this section of 

the document do not take into 

consideration the proposed monitoring 

and mitigation measures described later 

in this document (see the ‘‘Proposed 

Mitigation’’ and ‘‘Proposed Monitoring 

and Reporting’’ sections) which, as 

noted are designed to effect the least 

practicable adverse impact on affected 

marine mammal species and stocks. 

Anticipated Effects on Marine Mammal 

Habitat 

The proposed seismic survey is not 

anticipated to have any permanent 

impact on habitats used by the marine 

mammals in the proposed survey area, 

including the food sources they use (i.e., 

fish and invertebrates). Additionally, no 

physical damage to any habitat is 

anticipated as a result of conducting the 

proposed seismic survey. While it is 

anticipated that the specified activity 

may result in marine mammals avoiding 

certain areas due to temporary 

ensonification, this impact to habitat is 

temporary and reversible and was 

considered in further detail earlier in 

this document, as behavioral 

modification. 

The main impact associated with the 

proposed activity will be temporarily 

elevated noise levels and the associated 

direct effects on marine mammals, 

previously discussed in this notice. The 

next section discusses the potential 

impacts of anthropogenic sound sources 

on common marine mammal prey in the 

proposed survey area (i.e., fish and 

invertebrates). 

Anticipated Effects on Fish 

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 limited (see 

Appendix D of NSF’s EA). There are 

three types of potential effects of 

exposure to seismic surveys: (1) 

Pathological, (2) physiological, and (3) 

behavioral. Pathological effects involve 

lethal and temporary or permanent sublethal 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 could potentially 

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. The studies of 

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individual fish have often been on caged 

fish that were exposed to airgun pulses 

in situations not representative of an 

actual seismic survey. Thus, available 

information provides limited insight on 

possible real-world effects at the ocean 

or population scale. 

Hastings and Popper (2005), Popper 

(2009), and Popper and Hastings 

(2009a,b) provided recent critical 

reviews of the known effects of sound 

on fish. The following sections provide 

a general synopsis of the 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 

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 D of 

NSF’s EA). For a given sound to result 

in hearing loss, the sound must exceed, 

by some substantial 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 are 

unknown; however, they likely depend 

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 papers with proper 

experimental methods, controls, and 

careful pathological investigation 

implicating sounds produced by actual 

seismic survey airguns in causing 

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 

(Coregonus nasus) exposed to five 

airgun shots were not significantly 

different from those of controls. 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 

airguns (less than 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 two 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 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; Thomsen, 2002; Hassel et 

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

al., 2006). 

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. However, Payne 

et al. (2009) reported no statistical 

differences in mortality/morbidity 

between control and exposed groups of 

capelin eggs or monkfish larvae. 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; 

Santulli et al., 1999; McCauley et al., 

2000a,b). 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 C 

of NSF’s EA). 

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 (e.g., 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. 

In general, any adverse effects on fish 

behavior or fisheries attributable to 

seismic testing may depend on the 

species in question and the nature of the 

fishery (season, duration, fishing 

method). They may also depend on the 

age of the fish, its motivational state, its 

size, and numerous other factors that are 

difficult, if not impossible, to quantify at 

this point, given such limited data on 

effects of airguns on fish, particularly 

under realistic at-sea conditions. 

Anticipated Effects on Invertebrates 

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 

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impinging sound field and not to the 

pressure component (Popper et al., 

2001; see also Appendix E of NSF’s EA). 

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. 

Literature reviews of the effects of 

seismic and other underwater sound on 

invertebrates were provided by 

Moriyasu et al. (2004) and Payne et al. 

(2008). 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. Appendix D of L-DEO’s EA 

provides a more detailed review of the 

literature on the effects of seismic 

survey sound on invertebrates. 

Pathological Effects—In water, lethal 

and sub-lethal injury to organisms 

exposed to seismic survey sound 

appears to 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 type of airgun array 

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, at most; 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 the article 

provides little evidence to support this 

claim. 

Andre et al. (2011) exposed four 

cephalopod species (Loligo vulgaris, 

Sepia officinalis, Octopus vulgaris, and 

Ilex coindetii) to two hours of 

continuous sound from 50 to 400 Hz at 

157 ± 5 dB re: 1 mPa. They reported 

lesions to the sensory hair cells of the 

statocysts of the exposed animals that 

increased in severity with time, 

suggesting that cephalopods are 

particularly sensitive to low-frequency 

sound. 

The received SPL was reported as 157 

± 5 dB re: 1 FPa, with peak levels at 175 

dB re 1 FPa. As in the McCauley et al. 

(2003) paper on sensory hair cell 

damage in pink snapper as a result of 

exposure to seismic sound, the 

cephalopods were subjected to higher 

sound levels than they would be under 

natural conditions, and they were 

unable to swim away from the sound 

source. 

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. Primary and 

secondary stress responses (i.e., changes 

in haemolymph levels of enzymes, 

proteins, etc.) of crustaceans have been 

noted several days or months after 

exposure to seismic survey sounds 

(Payne et al., 2007). 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. Changes in behavior could 

potentially affect such aspects as 

reproductive success, distribution, 

susceptibility to predation, and 

catchability by fisheries. Studies 

investigating the possible behavioral 

effects of exposure to seismic survey 

sound on crustaceans and cephalopods 

have been conducted on both uncaged 

and caged animals. In some cases, 

invertebrates exhibited 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 catch rate (Andriguetto-Filho et 

al., 2005). Similarly, Parry and Gason 

(2006) did not find any evidence that 

lobster catch rates were affected by 

seismic surveys. 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). 

Proposed Mitigation 

In order to issue an Incidental Take 

Authorization (ITA) under section 

101(a)(5)(D) of the MMPA, NMFS must 

set forth the permissible methods of 

taking pursuant to such activity, and 

other means of effecting the least 

practicable adverse impact on such 

species or stock and its habitat, paying 

particular attention to rookeries, mating 

grounds, and areas of similar 

significance, and the availability of such 

species or stock for taking for certain 

subsistence uses. 

L-DEO has based the mitigation 

measures described herein, to be 

implemented for the proposed seismic 

survey, on the following: 

(1) Protocols used during previous 

L-DEO seismic research cruises as 

approved by NMFS; 

(2) Previous IHA applications and 

IHAs approved and authorized by 

NMFS; and 

(3) Recommended best practices in 

Richardson et al. (1995), Pierson et al. 

(1998), and Weir and Dolman, (2007). 

To reduce the potential for 

disturbance from acoustic stimuli 

associated with the activities, L-DEO 

and/or its designees would to 

implement the following mitigation 

measures for marine mammals: 

(1) Proposed EZs; 

(2) Speed or course alteration; 

(3) Shut-down procedures; and 

(4) Ramp-up procedures. 

Proposed Exclusion Zones—L-DEO 

uses safety radii to designate EZs and to 

estimate take for marine mammals. 

Table 1 (presented earlier in this 

document) shows the distances at which 

three sound levels (160-, 180-, and 190- 

dB) are expected to be received from the 

two GI airguns. The 180 and 190 dB 

radii are shut-down criteria applicable 

to cetaceans and pinnipeds, 

respectively, as specified by NMFS 

(2000); these levels were used to 

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establish the EZs. If the PSO detects 

marine mammal(s) within or about to 

enter the appropriate EZ, L-DEO would 

shut down the airguns immediately. 

Speed or Course Alteration—If L-DEO 

detects a marine mammal outside the 

EZ and, based on its position and the 

relative motion, the marine mammal is 

likely to enter the EZ, L-DEO could 

change the vessel’s speed and/or direct 

course. L-DEO would implement speed 

or course operation if operationally 

practicable, thus minimizing the effect 

on the planned science objectives. 

L-DEO would monitor the activities and 

movements of the marine mammal 

(relative to the seismic vessel) to 

determine if the animal is approaching 

the applicable EZ. If the animal appears 

likely to enter the EZ, L-DEO would 

implement further mitigative actions, 

i.e., either further course alterations or 

a shut-down of the seismic source. 

Typically, during seismic operations, 

the source vessel is unable to change 

speed or course and one or more 

alternative mitigation measures will 

need to be implemented. 

Shut-down Procedures—L-DEO will 

shut down the operating airgun(s) if a 

marine mammal is seen outside the EZ 

for the airgun(s), and if the vessel’s 

speed and/or course cannot be changed 

to avoid having the animal enter the EZ, 

the seismic source will be shut-down 

before the animal is within the EZ. If a 

marine mammal is already within the 

EZ when first detected, the seismic 

source will be shut-down immediately. 

Following a shut-down, L-DEO will 

not resume airgun activity until the 

marine mammal has cleared the EZ. SIO 

will consider the animal to have cleared 

the EZ if: 

• A PSO has visually observed the 

animal leave the EZ, or 

• A PSO has not sighted the animal 

within the EZ for 15 min for species 

with shorter dive durations (i.e., small 

odontocetes or pinnipeds), or 30 min for 

species with longer dive durations (i.e., 

mysticetes and large odontocetes, 

including sperm, killer, and beaked 

whales). 

Ramp-up Procedures—L-DEO will 

follow a ramp-up procedure when the 

airgun array begins operating after a 

specified period without airgun 

operations or when a shut-down has 

exceeded that period. L-DEO proposes 

that, for the present cruise, this period 

would be approximately 15 min. L-DEO 

has used similar periods (approximately 

15 min) during previous L-DEO surveys. 

L-DEO will begin a ramp-up with a 

single GI airgun (105 in3) and will add 

the second GI airgun (105 in3) after five 

min. During ramp-up, the PSOs will 

monitor the EZ, and if marine mammals 

are sighted, L-DEO will implement a 

shut-down as though both GI airguns 

were operational. 

If the complete EZ has not been 

visible for at least 30 min prior to the 

start of operations in either daylight or 

nighttime, L-DEO will not commence 

the ramp-up. If one airgun has operated, 

ramp-up to full power will be 

permissible at night or in poor visibility, 

on the assumption that marine 

mammals will be alerted to the 

approaching seismic vessel by the 

sounds from the single airgun and could 

move away if they choose. A ramp-up 

from a shut-down may occur at night, 

but only where the EZ is small enough 

to be visible. SIO will not initiate a 

ramp-up of the airguns if a marine 

mammal is sighted within or near the 

applicable EZs during the day or close 

to the vessel at night. 

NMFS has carefully evaluated the 

applicant’s proposed mitigation 

measures and has considered a range of 

other measures in the context of 

ensuring that NMFS prescribes the 

means of effecting the least practicable 

adverse impact on the affected marine 

mammal species and stocks and their 

habitat. NMFS’s evaluation of potential 

measures included consideration of the 

following factors in relation to one 

another: 

(1) The manner in which, and the 

degree to which, the successful 

implementation of the measure is 

expected to minimize adverse impacts 

to marine mammals; 

(2) The proven or likely efficacy of the 

specific measure to minimize adverse 

impacts as planned; and 

(3) The practicability of the measure 

for applicant implementation. 

Based on NMFS’s evaluation of the 

applicant’s proposed measures, as well 

as other measures considered by NMFS 

or recommended by the public for 

previous low-energy seismic surveys, 

NMFS has preliminarily determined 

that the proposed mitigation measures 

provide the means of effecting the least 

practicable adverse impacts on marine 

mammal species or stocks and their 

habitat, paying particular attention to 

rookeries, mating grounds, and areas of 

similar significance. 

Proposed Monitoring and Reporting 

In order to issue an ITA for an 

activity, section 101(a)(5)(D) of the 

MMPA states that NMFS must set forth 

‘‘requirements pertaining to the 

monitoring and reporting of such 

taking.’’ The MMPA implementing 

regulations at 50 CFR 216.104(a)(13) 

indicate that requests for IHAs must 

include the suggested means of 

accomplishing the necessary monitoring 

and reporting that will result in 

increased knowledge of the species and 

of the level of taking or impacts on 

populations of marine mammals that are 

expected to be present in the action 

area. 

Proposed Monitoring 

L-DEO proposes to sponsor marine 

mammal monitoring during the 

proposed project, in order to implement 

the proposed mitigation measures that 

require real-time monitoring, and to 

satisfy the anticipated monitoring 

requirements of the IHA. L-DEO’s 

proposed Monitoring Plan is described 

below this section. L-DEO understands 

that this monitoring plan will be subject 

to review by NMFS, and that 

refinements may be required. The 

monitoring work described here has 

been planned as a self-contained project 

independent of any other related 

monitoring projects that may be 

occurring simultaneously in the same 

regions. L-DEO is prepared to discuss 

coordination of its monitoring program 

with any related work that might be 

done by other groups insofar as this is 

practical and desirable. 

Vessel-Based Visual Monitoring 

L-DEO will position PSOs aboard the 

seismic source vessel to watch for 

marine mammals near the vessel during 

daytime airgun operations and during 

any ramp-ups at night. PSOs will also 

watch for marine mammals near the 

seismic vessel for at least 30 min prior 

to the ramp-up of airgun operations after 

an extended shut-down (i.e., greater 

than approximately 15 min for this 

proposed cruise). When feasible, PSOs 

will conduct observations during 

daytime periods when the seismic 

system is not operating for comparison 

of sighting rates and behavior with and 

without airgun operations and between 

acquisition periods. Based on PSO 

observations, the airguns will be shutdown when marine mammals are 

observed within or about to enter a 

designated EZ. The EZ is a region in 

which a possibility exists of adverse 

effects on animal hearing or other 

physical effects. 

During seismic operations in the 

central Pacific Ocean, at least three 

PSOs will be based aboard the Langseth. 

L-DEO will appoint the PSOs with 

NMFS’ concurrence. At least one PSO 

will monitor the EZs during seismic 

operations. Observations will take place 

during ongoing daytime operations and 

nighttime ramp-ups of the airguns. 

PSO(s) will be on duty in shifts of 

duration no longer than four hours. The 

vessel crew will also be instructed to 

assist in detecting marine mammals. 

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The Langseth is a suitable platform for 

marine mammal observations. When 

stationed on the observation platform, 

the eye level will be approximately 21.5 

m (70.5 ft) above sea level, and the 

observer will have a good view around 

the entire vessel. During daytime, the 

PSVOs will scan the area around the 

vessel systematically with reticle 

binoculars (e.g., 7 × 50 Fujinon), Big-eye 

binoculars (25 × 150), and with the 

naked eye. During darkness, night 

vision devices (NVDs) will be available 

(ITT F500 Series Generation 3 

binocular-image intensifier or 

equivalent), when required. Laser rangefinding binoculars (Leica LRF 1200 laser 

rangefinder or equivalent) will be 

available to assist with distance 

estimation. Those are useful in training 

observers to estimate distances visually, 

but are generally not useful in 

measuring distances to animals directly; 

that is done primarily with the reticles 

in the binoculars. 

When the PSOs observe marine 

mammals within or about to enter the 

designated EZ, the Langseth will 

immediately shut-down the airguns if 

necessary. The PSOs will continue to 

maintain watch to determine when the 

animal(s) are outside the EZ by visual 

confirmation. Airgun operations will 

not resume until the animal is 

confirmed to have left the EZ, or if not 

observed after 15 min for species with 

shorter dive durations (small 

odontocetes and pinnipeds) or 30 min 

for species with longer dive durations 

(mysticetes and large odontocetes, 

including sperm, killer, and beaked 

whales). 

PSO Data and Documentation 

PSOs 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 

shut-down of the airguns when a marine 

mammal is within or near the EZ. 

Observations will also be made during 

daytime periods when the Langseth is 

underway without seismic operations 

(i.e., transits to, from, and through the 

study area) to collect baseline biological 

data. 

When a sighting is made, the 

following information about the sighting 

will be recorded: 

1. Species, group size, 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 

airguns or vessel (e.g., none, avoidance, 

approach, paralleling, etc.), and 

behavioral pace. 

2. Time, location, heading, speed, 

activity of the vessel, Beaufort sea state, 

visibility, and sun glare. 

The data listed under (2) 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 shut-downs of the 

seismic source, will be recorded in a 

standardized format. The data accuracy 

will be verified by the PSOs 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. 

Vessel-based observations by the PSO 

will provide the following information: 

1. The basis for real-time mitigation 

(airgun shut-down). 

2. Information needed to estimate the 

number of marine mammals potentially 

taken by harassment, which must 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. Information to compare the 

distance and distribution of marine 

mammals relative to the source vessel at 

times with and without seismic activity. 

5. Data on the behavior and 

movement patterns of marine mammals 

seen at times with and without seismic 

activity. 

L-DEO will submit a report to NMFS 

and NSF 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 provide 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 number and 

nature of exposures that could result in 

potential ‘‘takes’’ of marine mammals by 

harassment or in other ways. After the 

report is considered final, it will be 

publicly available on the NMFS and 

NSF Web sites. 

In the unanticipated event that the 

specified activity clearly causes the take 

of a marine mammal in a manner 

prohibited by the IHA (if issued), such 

as an injury (Level A harassment), 

serious injury or mortality (e.g., shipstrike, gear interaction, and/or 

entanglement), L-DEO shall 

immediately cease the specified 

activities and immediately report the 

incident to the Chief of the Permits and 

Conservation Division, Office of 

Protected Resources, NMFS, at 301– 

427–8401 and/or by email to 

Jolie.Harrison@noaa.gov and 

ITP.Cody@noaa.gov and the Pacific 

Islands Regional Stranding Coordinator 

at 808–944–2269 

(David.Schofield@noaa.gov). The report 

must include the following information: 

• Time, date, and location (latitude/ 

longitude) of the incident; 

• Name and type of vessel involved; 

• Vessel’s speed during and leading 

up to the incident; 

• Description of the incident; 

• Status of all sound source use in the 

24 hours preceding the incident; 

• Water depth; 

• Environmental conditions (e.g., 

wind speed and direction, Beaufort sea 

state, cloud cover, and visibility); 

• Description of all marine mammal 

observations in the 24 hours preceding 

the incident; 

• Species identification or 

description of the animal(s) involved; 

• Fate of the animal(s); and 

• Photographs or video footage of the 

animal(s) (if equipment is available). 

Activities will not resume until NMFS 

is able to review the circumstances of 

the prohibited take. NMFS will work 

with L-DEO to determine what is 

necessary to minimize the likelihood of 

further prohibited take and ensure 

MMPA compliance. L-DEO may not 

resume their activities until notified by 

NMFS via letter, email, or telephone. 

In the event that L-DEO discovers an 

injured or dead marine mammal, and 

the lead PSVO determines that the cause 

of the injury or death is unknown and 

the death is relatively recent (i.e., in less 

than a moderate state of decomposition 

as described in the next paragraph), 

L-DEO will immediately report the 

incident to the Chief of the Permits and 

Conservation Division, Office of 

Protected Resources, NMFS, at 301– 

427–8401 and/or by email to 

Jolie.Harrison@noaa.gov and 

ITP.Cody@noaa.gov and the Pacific 

Islands Regional Stranding Coordinator 

at 808–944–2269 

(David.Schofield@noaa.gov). The report 

must include the same information 

identified in the paragraph above. 

Activities may continue while NMFS 

reviews the circumstances of the 

incident. NMFS will work with L-DEO 

to determine whether modifications in 

the activities are appropriate. 

In the event that L-DEO discovers an 

injured or dead marine mammal, and 

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the lead PSVO determines that the 

injury or death is not associated with or 

related to the activities authorized in the 

IHA (e.g., previously wounded animal, 

carcass with moderate to advanced 

decomposition, or scavenger damage), 

L-DEO will report the incident to the 

Chief of the Permits and Conservation 

Division, Office of Protected Resources, 

NMFS, at 301–427–8401 and/or by 

email to Jolie.Harrison@noaa.gov and 

ITP.Cody@noaa.gov and the Pacific 

Islands Regional Stranding Coordinator 

at 808–944–2269 

(David.Schofield@noaa.gov), within 24 

hours of the discovery. L-DEO will 

provide photographs or video footage (if 

available) or other documentation of the 

stranded animal sighting to NMFS. 

Activities may continue while NMFS 

reviews the circumstances of the 

incident. 

Estimated Take by Incidental 

Harassment 

Except with respect to certain 

activities not pertinent here, the MMPA 

defines ‘‘harassment’’ as: 

any act of pursuit, torment, or annoyance 

which (i) has the potential to injure a marine 

mammal or marine mammal stock in the wild 

[Level A harassment]; or (ii) has the potential 

to disturb a marine mammal or marine 

mammal stock in the wild by causing 

disruption of behavioral patterns, including, 

but not limited to, migration, breathing, 

nursing, breeding, feeding, or sheltering 

[Level B harassment]. 

Only take by Level B harassment is 

anticipated and proposed to be 

authorized as a result of the proposed 

marine seismic survey in the central 

Pacific Ocean. Acoustic stimuli (i.e., 

increased underwater sound) generated 

during the operation of the seismic 

airgun array may have the potential to 

cause marine mammals in the survey 

area to be exposed to sounds at or 

greater than 160 dB or cause temporary, 

short-term changes in behavior. There is 

no evidence that the planned activities 

could result in injury, serious injury, or 

mortality within the specified 

geographic area for which L-DEO seeks 

the IHA. The required mitigation and 

monitoring measures will minimize any 

potential risk for injury, serious injury, 

or mortality. 

The following sections describe 

L-DEO’s methods to estimate take by 

incidental harassment and present the 

applicant’s estimates of the numbers of 

marine mammals that could be affected 

during the proposed seismic program. 

The estimates are based on a 

consideration of the number of marine 

mammals that could be disturbed 

appreciably by operations with the two 

GI airgun array to be used during 

approximately 2,316 km2 (894 mi2) 

(includes primary and secondary lines 

and an additional 25 percent 

contingency) of survey lines in the 

central Pacific Ocean. 

L-DEO assumes that, during 

simultaneous operations of the airgun 

array and the other sources, any marine 

mammals close enough to be affected by 

the MBES, SBP, and ADCP would 

already be affected by the airguns. 

However, whether or not the airguns are 

operating simultaneously with the other 

sources, marine mammals are expected 

to exhibit no more than short-term and 

inconsequential responses to the MBES, 

SBP, and ADCP given their 

characteristics (e.g., narrow, downwarddirected beam) and other considerations 

described previously. Such reactions are 

not considered to constitute ‘‘taking’’ 

(NMFS, 2001). Therefore, L-DEO 

provides no additional allowance for 

animals that could be affected by sound 

sources other than airguns. 

Density data on the marine mammal 

species in the proposed survey area are 

available from two sources: (1) the 

NMFS Southwest Fishery Science 

Center (SWFSC) habitat model that 

estimates eastern tropical Pacific Ocean 

(ETP) cetacean densities on a finer 

spatial scale than traditional linetransect analyses by using a continuous 

function of habitat variables, e.g., sea 

surface temperature, depth, distance 

from shore, and prey density (Barlow et 

al., 2009b); and (2) densities from the 

offshore stratum of the surveys of 

Hawaiian waters conducted in August– 

November 2002 (Barlow, 2006). 

For the ETP ship transect surveys, the 

SWFSC based the models on data from 

12 SWFSC ship-based cetacean and 

ecosystem assessment surveys 

conducted during July–December 1986– 

2006, extending east of the proposed 

survey area. 

The models have been incorporated 

into a web-based Geographic 

Information System (GIS) developed by 

Duke University’s Department of 

Defense Strategic Environmental 

Research and Development Program 

(SERDP) team in close collaboration 

with the SWFSC SERDP team (Read et 

al., 2009). For the cetacean species in 

the model, L-DEO used the GIS to obtain 

mean densities in the proposed survey 

area, i.e., in a rectangle bounded by 150 

and 156° W and 5 and 10° N. For 

species not included in the model, we 

used densities from the offshore stratum 

of the surveys of Hawaiian waters 

conducted in August–November 2002 

(Barlow 2006). 

Table 3 in L-DEO’s application shows 

estimated densities for each cetacean 

species that could occur in the proposed 

survey area. They have corrected the 

densities for both trackline detection 

probability and availability bias by the 

authors. Trackline detection probability 

bias is associated with diminishing 

sightability with increasing lateral 

distance from the trackline [f(0)]. 

Availability bias refers to the fact that 

there is less than a 100 percent 

probability of sighting an animal that is 

present along the survey trackline [g(0)]. 

Because survey effort within the 

proposed survey area is limited, and 

densities for some species are from 

offshore Hawaiian waters, there is some 

uncertainty about the representativeness 

of the data and the assumptions used in 

the calculations below. However, the 

approach used here is believed to be the 

best available approach. 

L-DEO’s estimates of exposures to 

various sound levels assume that the 

proposed surveys will be completed. As 

is typical during offshore ship surveys, 

inclement weather and equipment 

malfunctions are likely to cause delays 

and may limit the number of useful linekilometers of seismic operations that 

can be undertaken. L-DEO has included 

an additional 25 percent of line 

transects to account for mission 

uncertainty and to accommodate turns 

and lines that may need to be repeated. 

Furthermore, any marine mammal 

sightings within or near the designated 

exclusion zones will result in the power 

down or shut down of seismic 

operations as a mitigation measure. 

Thus, the following estimates of the 

numbers of marine mammals potentially 

exposed to sound levels of 160 dB re: 1 

mPa are precautionary and probably 

overestimate the actual numbers of 

marine mammals that might be 

involved. These estimates also assume 

that there will be no weather, 

equipment, or mitigation delays, which 

is highly unlikely. 

L-DEO estimated the number of 

different individuals that may be 

exposed to airgun sounds with received 

levels greater than or equal to 160 dB re: 

1 mPa on one or more occasions by 

considering the total marine area that 

would be within the 160-dB radius 

around the operating airgun array on at 

least one occasion and the expected 

density of marine mammals. The 

number of possible exposures 

(including repeated exposures of the 

same individuals) can be estimated by 

considering the total marine area that 

would be within the 160-dB radius 

around the operating airguns, including 

areas of overlap. In the proposed survey, 

the seismic lines are parallel and in 

close proximity; thus individuals could 

be exposed on two or more occasions. 

The area including overlap is 1.01 times 

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the area excluding overlap. Thus a 

marine mammal that stayed in the 

survey area during the entire survey 

could be exposed once, on average. 

Moreover, it is unlikely that a particular 

animal would stay in the area during the 

entire survey. 

The number of different individuals 

potentially exposed to received levels 

greater than or equal to 160 re: 1 mPa 

was calculated by multiplying: 

(1) The expected species density, 

times 

(2) The anticipated area to be 

ensonified to that level during airgun 

operations excluding overlap, which is 

approximately 1,853 km2 (715.4 mi2). 

The area expected to be ensonified 

was determined by entering the planned 

survey lines into a MapInfo GIS, using 

the GIS to identify the relevant areas by 

‘‘drawing’’ the applicable 160-dB buffer 

(see Table 1) around each seismic line, 

and then calculating the total area 

within the buffers. Areas of overlap 

were included only once when 

estimating the number of individuals 

exposed. Applying this approach, 

approximately 2,316 km2 (894.2 mi2) 

would be within the 160-dB isopleth on 

one or more occasions during the 

survey. Because this approach does not 

allow for turnover in the mammal 

populations in the study area during the 

course of the survey, the actual number 

of individuals exposed could be 

underestimated. However, the approach 

assumes that no cetaceans will move 

away from or toward the trackline as the 

Langseth approaches in response to 

increasing sound levels prior to the time 

the levels reach 160 dB, which will 

result in overestimates for those species 

known to avoid seismic vessels. 

Table 3 in this notice shows estimates 

of the number of individual cetaceans 

that potentially could be exposed to 

greater than or equal to 160 dB re: 1 mPa 

during the seismic survey if no animals 

moved away from the survey vessel. The 

requested take authorization is shown in 

the far right column of Table 3. For 

endangered species, the requested take 

authorization reflects the mean group 

size in the ETP (Jackson et al., 2008) for 

the particular species in cases where the 

calculated number of individuals 

exposed was between 0.05 and the mean 

group size (i.e., for the sperm whale). 

For non-listed species, the requested 

take authorization reflects the mean 

group size in the SWFSC survey area 

(Barlow et al., 2008) for the particular 

species in cases where the calculated 

number of individuals exposed was 

between one and the mean group size. 

The total estimate of the number of 

individual cetaceans that could be 

exposed to seismic sounds with 

received levels greater than or equal to 

160 dB re: 1 mPa during the proposed 

survey is 828 (see Table 3 in this notice; 

Table 4 in L-DEO’s application). That 

total includes: four Bryde’s whales or 

0.01 percent of the regional population; 

and 7 sperm whales (also listed as 

endangered) or 0.03 percent of the 

regional population could be exposed 

during the survey. L-DEO did not 

estimate take of endangered humpback, 

sei, blue, or fin whales or Hawaiian 

monk seals because of the low 

likelihood of encountering these species 

during the cruise. In addition, 18 beaked 

whales (16 Cuvier’s, one Longman’s, 

and one Mesoplodon spp.) could be 

exposed during the survey (see Table 3 

in this notice; Table 4 in L-DEO’s 

application). Most (94.7 percent) of the 

cetaceans that could be potentially 

exposed are delphinids (e.g., spinner, 

pantropical spotted, and striped 

dolphins are estimated to be the most 

common species in the area) with 

maximum estimates ranging from four 

to 425 species exposed to levels greater 

than or equal to 160 dB re: 1 mPa. 

TABLE 3—ESTIMATES OF THE POSSIBLE NUMBERS OF MARINE MAMMALS EXPOSED TO DIFFERENT SOUND LEVELS

DURING L-DEO’S PROPOSED SEISMIC SURVEY IN THE CENTRAL PACIFIC OCEAN DURING MAY, 2012 

Species 

Estimated number 

of individuals 

exposed to 

sound levels 

≥ 160 dB re: 1 

μPa 1

Approximate 

percent of regional 

population 2

Requested take 

authorization 

Bryde’s whale ............................................................................................................ 1 0.01 4 4 

Blue whale ................................................................................................................. 0 < 0.01 0 

Sperm whale .............................................................................................................. 7 0.03 4 8 

Dwarf sperm whale .................................................................................................... 18 0.16 18

Cuvier’s beaked whale .............................................................................................. 16 0.08 16 

Longman’s beaked whale .......................................................................................... 1 0.36 4 14 

Mesoplodon spp.3 ...................................................................................................... 1 <0.01 4 4 

Rough-toothed dolphin .............................................................................................. 3 <0.01 4 13 

Bottlenose dolphin ..................................................................................................... 11 <0.01 4 12 

Pantropical spotted dolphin ....................................................................................... 279 0.06 279 

Spinner dolphin .......................................................................................................... 425 0.02 425 

Striped dolphin ........................................................................................................... 38 <0.01 4 46 

Fraser’s dolphin ......................................................................................................... 11 <0.01 4 182 

Risso’s dolphin ........................................................................................................... 2 <0.01 4 14 

Melon-headed whale ................................................................................................. 3 0.01 4 101 

False killer whale ....................................................................................................... 0 <0.01 4 9 

Short-finned pilot whale ............................................................................................. 12 <0.01 4 24 

1Estimates are based on densities from Table 3 and an ensonified area (including 25 percent contingency). 

2 Regional population size estimates are from Table 2. 

3 Includes ginkgo-toothed and/or Blainville’s beaked whales. 

4 Requested take authorization increased to mean group size (see text on page 40). 

Encouraging and Coordinating 

Research 

L-DEO and NSF will coordinate the 

planned marine mammal monitoring 

program associated with the seismic 

survey in the central Pacific Ocean with 

any parties that may have or express an 

interest in the proposed seismic survey 

area. L-DEO and NSF have coordinated, 

and will continue to coordinate, with 

other applicable Federal agencies as 

required, and will comply with their 

requirements. Pursuant to IHA 

requirements, L-DEO will submit a 

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monitoring report to NMFS 90 days after 

the proposed survey. 

Negligible Impact and Small Numbers 

Analysis and Determination 

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.’’ In making a 

negligible impact determination, NMFS 

evaluated factors such as: 

(1) The number of anticipated 

injuries, serious injuries, or mortalities; 

(2) The number, nature, and intensity, 

and duration of Level B harassment (all 

relatively limited); 

(3) The context in which the takes 

occur (i.e., impacts to areas of 

significance, impacts to local 

populations, and cumulative impacts 

when taking into account successive/ 

contemporaneous actions when added 

to baseline data); 

(4) The status of stock or species of 

marine mammals (i.e., depleted, not 

depleted, decreasing, increasing, stable, 

and impact relative to the size of the 

population); 

(5) Impacts on habitat affecting rates 

of recruitment/survival; and 

(6) The effectiveness of monitoring 

and mitigation measures (i.e., the 

manner and degree in which the 

measure is likely to reduce adverse 

impacts to marine mammals, the likely 

effectiveness of the measures, and the 

practicability of implementation). 

For reasons stated previously in this 

document, the specified activities 

associated with the marine seismic 

survey are not likely to cause PTS, or 

other non-auditory injury, serious 

injury, or death because: 

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; 

(1) The potential for temporary or 

permanent hearing impairment is 

relatively low and would likely be 

avoided through the incorporation of 

the required monitoring and mitigation 

measures (described above this section); 

(2) The fact that cetaceans would have 

to be closer than 70 m (229.7 ft) in deep 

water when the two GI airgun array is 

in 3 m (9.8 ft) tow depth from the vessel 

to be exposed to levels of sound 

believed to have even a minimal chance 

of causing PTS; and 

(3) The likelihood that marine 

mammal detection ability by trained 

PSOs is high at close proximity to the 

vessel. 

No injuries, serious injuries, or 

mortalities are anticipated to occur as a 

result of L-DEO’s planned marine 

seismic survey, and none are proposed 

to be authorized by NMFS. Only shortterm, behavioral disturbance is 

anticipated to occur due to the brief and 

sporadic duration of the survey 

activities. Table 3 in this document 

outlines the number of Level B 

harassment takes that are anticipated as 

a result of the activities. Due to the 

nature, degree, and context of Level B 

(behavioral) harassment anticipated and 

described (see Potential Effects on 

Marine Mammals section above) in this 

notice, the proposed activity is not 

expected to impact rates of recruitment 

or survival for any affected species or 

stock. 

Many animals perform vital functions, 

such as feeding, resting, traveling, and 

socializing, on a diel cycle (i.e., 24 hr 

cycle). Behavioral reactions to noise 

exposure (such as disruption of critical 

life functions, displacement, or 

avoidance of important habitat) are 

more likely to be significant if they last 

more than one diel cycle or recur on 

subsequent days (Southall et al., 2007). 

While seismic operations are 

anticipated to occur on consecutive 

days, the entire duration of the survey 

is not expected to last more than six 

days and the Langseth will be 

continuously moving along planned 

tracklines. Therefore, the seismic survey 

will be increasing sound levels in the 

marine environment surrounding the 

vessel for several weeks in the study 

area. Of the 26 marine mammal species 

under NMFS’ jurisdiction likely to 

occur in the survey area, six are listed 

as endangered under the ESA: The 

humpback, sei, fin, blue, and sperm 

whale and the Hawaiian monk seal. 

These species are also considered 

depleted under the MMPA. However, no 

take of endangered humpback, sei, blue, 

or fin whales or Hawaiian monk seals 

was requested because of the low 

likelihood of encountering these species 

during the cruise. As mentioned 

previously, the survey would not occur 

in any areas designated as critical 

habitat for ESA-listed species and 

would not adversely impact marine 

mammal habitat. There is generally 

insufficient data to determine 

population trends for the other depleted 

species in the study area. To protect 

these animals (and other marine 

mammals in the study area), L-DEO 

must cease or reduce airgun operations 

if animals enter designated zones. No 

injury, serious injury, or mortality is 

expected to occur and due to the nature, 

degree, and context of the Level B 

harassment anticipated, the activity is 

not expected to impact rates of 

recruitment or survival. 

As mentioned previously, NMFS 

estimates that 16 species of marine 

mammals under its jurisdiction could be 

potentially affected by Level B 

harassment over the course of the 

proposed IHA. For each species, these 

numbers are small (each less than one 

percent) relative to the regional 

population size. The population 

estimates for the marine mammal 

species that may be taken by harassment 

were provided in Table 2 of this 

document. 

NMFS’ practice has been to apply the 

160 dB re 1 mPa (rms) received level 

threshold for underwater impulse sound 

levels to determine whether take by 

Level B harassment occurs. Southall et 

al. (2007) provide a severity scale for 

ranking observed behavioral responses 

of both free-ranging marine mammals 

and laboratory subjects to various types 

of anthropogenic sound (see Table 4 in 

Southall et al. [2007]). 

NMFS has preliminarily determined, 

provided that the aforementioned 

mitigation and monitoring measures are 

implemented, that the impact of 

conducting a marine seismic survey in 

the central Pacific Ocean, May, 2012, 

may result, at worst, in a temporary 

modification in behavior and/or lowlevel physiological effects (Level B 

harassment) of small numbers of certain 

species of marine mammals. See Table 

3 (above) for the requested authorized 

take numbers of cetaceans. 

While behavioral modifications, 

including temporarily vacating the area 

during the operation of the airgun(s), 

may be maCde by these species to avoid 

the resultant acoustic disturbance, the 

availability of alternate areas within this 

region and the short and sporadic 

duration of the research activities, have 

led NMFS to preliminarily determine 

that this action will have a negligible 

impact on the species in the specified 

geographic region. 

Based on the analysis contained 

herein of the likely effects of the 

specified activity on marine mammals 

and their habitat, and taking into 

consideration the implementation of the 

mitigation and monitoring measures, 

NMFS preliminarily finds that L-DEO’s 

planned research activities, will result 

in the incidental take of small numbers 

of marine mammals, by Level B 

harassment only, and that the total 

taking from the marine seismic survey 

will have a negligible impact on the 

affected species or stocks of marine 

mammals; and that impacts to affected 

species or stocks of marine mammals 

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19262 Federal Register / Vol. 77, No. 62 / Friday, March 30, 2012 / Notices 

have been mitigated to the lowest level 

practicable. 

Impact on Availability of Affected 

Species or Stock for Taking for 

Subsistence Uses 

Section 101(a)(5)(D) also requires 

NMFS to determine that the 

authorization will not have an 

unmitigable adverse effect on the 

availability of marine mammal species 

or stocks for subsistence use. There are 

no relevant subsistence uses of marine 

mammals in the study area (offshore 

waters of the Line Islands in the central 

Pacific Ocean) that implicate MMPA 

section 101(a)(5)(D). 

Endangered Species Act 

Of the species of marine mammals 

that may occur in the proposed survey 

area, several are listed as endangered 

under the ESA, including the 

humpback, sei, fin, blue, and sperm 

whale and Hawaiian monk seal. L-DEO 

did not request take of endangered 

humpback, sei, blue, or fin whales or 

Hawaiian monk seals because of the low 

likelihood of encountering these species 

during the cruise. As mentioned 

previously, the survey would not occur 

in any areas designated as critical 

habitat for ESA-listed species and 

would not adversely impact marine 

mammal habitat. 

Under section 7 of the ESA, NSF has 

initiated formal consultation with the 

NMFS’, Office of Protected Resources, 

Endangered Species Act Interagency 

Cooperation Division on this proposed 

seismic survey. NMFS’ Office of 

Protected Resources, Permits and 

Conservation Division has initiated 

formal consultation under section 7 of 

the ESA with NMFS’ Office of Protected 

Resources, Endangered Species Act 

Interagency Cooperation Division to 

obtain a Biological Opinion evaluating 

the effects of issuing the IHA on 

threatened and endangered marine 

mammals and, if appropriate, 

authorizing incidental take. NMFS will 

conclude formal section 7 consultation 

prior to making a determination on 

whether or not to issue the IHA. If the 

IHA is issued, NSF and L-DEO, in 

addition to the mitigation and 

monitoring requirements included in 

the IHA, will be required to comply 

with the Terms and Conditions of the 

Incidental Take Statement 

corresponding to NMFS’ Biological 

Opinion issued to both NSF and NMFS’ 

Office of Protected Resources. 

National Environmental Policy Act 

(NEPA) 

With its complete application, NSF 

and L-DEO provided NMFS a 

‘‘Environmental Assessment and 

Finding of No Significant Impact 

(FONSI) Determination Pursuant to the 

National Environmental Policy Act, 

(NEPA: 42 U.S.C. 4321 et seq.) and 

Executive Order 12114 for a ‘‘Marine 

Geophysical Survey by the R/V Marcus 

G. Langseth in the Central Pacific Ocean 

May, 2012,’’ which incorporates an 

‘‘Environmental Assessment of a Marine 

Geophysical Survey by the R/V Marcus 

G. Langseth in the central Pacific Ocean, 

May, 2012,’’ prepared by LGL on behalf 

of NSF and L-DEO. The EA analyzes the 

direct, indirect, and cumulative 

environmental impacts of the specified 

activities on marine mammals including 

those listed as threatened or endangered 

under the ESA. NMFS conducted an 

independent review and evaluation of 

the document for sufficiency and 

compliance with the Council of 

Environmental Quality and NOAA 

Administrative Order 216–6 § 5.09(d), 

Environmental Review Procedures for 

Implementing the National 

Environmental Policy Act, and 

determined that issuance of the IHA is 

not likely to result in significant impacts 

on the human environment. 

Consequently, NMFS plans to adopt 

NSF’s EA and prepared a FONSI for the 

issuance of the IHA. An Environmental 

Impact Statement is not required and 

will not be prepared for the action. 

Proposed Authorization 

NMFS proposes to issue an IHA to LDEO for conducting a marine 

geophysical survey in the central Pacific 

Ocean, provided the previously 

mentioned mitigation, monitoring, and 

reporting requirements are incorporated. 

The duration of the IHA would not 

exceed one year from the date of its 

issuance. 

Information Solicited 

NMFS requests interested persons to 

submit comments and information 

concerning this proposed project and 

NMFS’ preliminary determination of 

issuing an IHA (see ADDRESSES). 

Concurrent with the publication of this 

notice in the Federal Register, NMFS is 

forwarding copies of this application to 

the Marine Mammal Commission and 

its Committee of Scientific Advisors. 

Dated: March 26, 2012. 

James H. Lecky, 

Director, Office of Protected Resources, 

National Marine Fisheries Service. 

[FR Doc. 2012–7717 Filed 3–29–12; 8:45 am] 

BILLING CODE 3510–22–P 

COMMITTEE FOR PURCHASE FROM 

PEOPLE WHO ARE BLIND OR 

SEVERELY DISABLED 

Procurement List; Additions 

AGENCY: Committee for Purchase From 

People Who Are Blind or Severely 

Disabled. 

ACTION: Additions to the Procurement 

List. 

SUMMARY: This action adds services to 

the Procurement List that will be 

provided by nonprofit agencies 

employing persons who are blind or 

have other severe disabilities. 

DATES: Effective Date: 4/30/2012. 

ADDRESSES: Committee for Purchase 

From People Who Are Blind or Severely 

Disabled, Jefferson Plaza 2, Suite 10800, 

1421 Jefferson Davis Highway, 

Arlington, Virginia, 22202–3259. 

FOR FURTHER INFORMATION CONTACT: 

Barry S. Lineback, Telephone: (703) 

603–7740, Fax: (703) 603–0655, or email 

CMTEFedReg@AbilityOne.gov. 

SUPPLEMENTARY INFORMATION: 

Additions 

On 12/23/2011 (76 FR 80346), 

1/6/2012 (77 FR 780) and 2/3/2012 (77 

FR 5495–5496), the Committee for 

Purchase From People Who Are Blind 

or Severely Disabled published notices 

of proposed additions to the 

Procurement List. 

After consideration of the material 

presented to it concerning capability of 

qualified nonprofit agencies to provide 

the services and impact of the additions 

on the current or most recent 

contractors, the Committee has 

determined that the services listed 

below are suitable for procurement by 

the Federal Government under 41 U.S.C. 

8501–8506 and 41 CFR 51–2.4. 

Regulatory Flexibility Act Certification 

I certify that the following action will 

not have a significant impact on a 

substantial number of small entities. 

The major factors considered for this 

certification were: 

1. The action will not result in any 

additional reporting, recordkeeping or 

other compliance requirements for small 

entities other than the small 

organizations that will provide the 

services to the Government. 

2. The action will result in 

authorizing small entities to provide the 

services to the Government. 

3. There are no known regulatory 

alternatives which would accomplish 

the objectives of the Javits-WagnerO’Day Act (41 U.S.C. 8501–8506) in 

connection with the services proposed 

for addition to the Procurement List. 

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