15060 Federal Register / Vol. 80, No. 54 / Friday, March 20, 2015 / Notices 

DEPARTMENT OF COMMERCE 

National Oceanic and Atmospheric 

Administration 

RIN 0648–XD727 

Takes of Marine Mammals Incidental to 

Specified Activities; Low-Energy 

Marine Geophysical Survey in the 

Southwest Pacific Ocean, East of New 

Zealand, May to June 2015 

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 the Scripps Institution 

of Oceanography (SIO), on behalf of SIO 

and the U.S. National Science 

Foundation (NSF), for an Incidental 

Harassment Authorization (IHA) to take 

marine mammals, by harassment, 

incidental to conducting a low-energy 

marine geophysical (seismic) survey in 

the Southwest Pacific Ocean, East of 

New Zealand, May to June 2015. 

Pursuant to the Marine Mammal 

Protection Act (MMPA), NMFS is 

requesting comments on its proposal to 

issue an IHA to SIO to incidentally 

harass, by Level B harassment only, 32 

species of marine mammals during the 

specified activity. 

DATES: Comments and information must 

be received no later than April 20, 2015. 

ADDRESSES: Comments on the 

application should be addressed to Jolie 

Harrison, 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.Goldstein@noaa.gov. 

Please include 0648–XD727 in the 

subject line. 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 25- 

megabyte file size. 

Instructions: All comments received 

are a part of the public record and will 

generally be posted to: http://

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

incidental/ 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. 

A copy of the IHA application may be 

obtained by writing to the address 

specified above, telephoning the contact 

listed here (see FOR FURTHER

INFORMATION CONTACT) or visiting the 

Internet at: http://www.nmfs.noaa.gov/

pr/permits/incidental/. Documents cited 

in this notice may also be viewed by 

appointment, during regular business 

hours, at the aforementioned address. 

A ‘‘Draft Environmental Analysis of a 

Low-Energy Marine Geophysical Survey 

by the R/V Roger Revelle in the 

Southwest Pacific Ocean, East of New 

Zealand, May to June 2015’’ (Draft 

Environmental Analysis) in accordance 

with the National Environmental Policy 

Act (NEPA) and the regulations 

published by the Council of 

Environmental Quality (CEQ), has been 

prepared on behalf of NSF and SIO. It 

is posted at the foregoing site. NMFS 

has independently evaluated the Draft 

Environmental Analysis and has 

prepared a separate NEPA analysis 

titled ‘‘Draft Environmental Assessment 

on the Issuance of an Incidental 

Harassment Authorization to the 

Scripps Institution of Oceanography to 

Take Marine Mammals by Harassment 

Incidental to a Low-Energy Marine 

Geophysical Survey in the Southwest 

Pacific Ocean, East of New Zealand, 

May to June 2015.’’ Information in the 

SIO’s IHA application, Draft 

Environmental Analysis, Draft EA and 

this notice of the proposed IHA 

collectively provide the environmental 

information related to proposed 

issuance of the IHA for public review 

and comment. NMFS will review all 

comments submitted in response to this 

notice as we complete the NEPA 

process, including a decision of whether 

to sign a Finding of No Significant 

Impact (FONSI), prior to a final decision 

on the IHA request. 

FOR FURTHER INFORMATION CONTACT: 

Howard Goldstein or Jolie Harrison, 

Office of Protected Resources, NMFS, 

301–427–8401. 

SUPPLEMENTARY INFORMATION: 

Background 

Sections 101(a)(5)(A) and (D) of the 

MMPA, (16 U.S.C. 1361 et seq.) direct 

the Secretary of Commerce (Secretary) 

to allow, upon request, the incidental, 

but not intentional, taking of small 

numbers of marine mammals by United 

States citizens who engage in a specified 

activity (other than commercial fishing) 

within a specified geographical region if 

certain findings are made and either 

regulations are issued or, if the taking is 

limited to harassment, a notice of a 

proposed authorization is provided to 

the public for review. 

An authorization for incidental 

takings shall be granted if NMFS finds 

that the taking will have a negligible 

impact on the species or stock(s), will 

not have an unmitigable adverse impact 

on the availability of the species or 

stock(s) for subsistence uses (where 

relevant), and if the permissible 

methods of taking and requirements 

pertaining to the mitigation, monitoring 

and reporting of such takings are set 

forth. NMFS has defined ‘‘negligible 

impact’’ in 50 CFR 216.103 as ‘‘. . . an 

impact resulting from the specified 

activity that cannot be reasonably 

expected to, and is not reasonably likely 

to, adversely affect the species or stock 

through effects on annual rates of 

recruitment or survival.’’ 

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

established an expedited process by 

which citizens of the United States can 

apply for an authorization to 

incidentally take small numbers of 

marine mammals by harassment. 

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. 

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 

On December 15, 2014, NMFS 

received an application from SIO, on 

behalf of SIO and NSF, requesting that 

NMFS issue an IHA for the take, by 

Level B harassment only, of small 

numbers of marine mammals incidental 

to conducting a low-energy marine 

seismic survey as well as heat-flow 

measurements in the Southwest Pacific 

Ocean, at three sites off the east coast of 

New Zealand, during May to June 2015. 

The sediment coring component of the 

proposed project, which was described 

in the IHA application and Draft 

Environmental Analysis, was not 

funded and no piston or gravity coring 

for seafloor samples would be 

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Federal Register / Vol. 80, No. 54 / Friday, March 20, 2015 / Notices 15061 

conducted during the low-energy 

seismic survey. The low-energy seismic 

survey would take place within the 

Exclusive Economic Zone (EEZ) and 

outside the territorial waters of New 

Zealand. On behalf of SIO, the U.S. 

Department of State is seeking 

authorization from New Zealand for 

clearance to work within the EEZ. 

The research would be conducted by 

Oregon State University and funded by 

the U.S. National Science Foundation 

(NSF). SIO plan to use one source 

vessel, the R/V Roger Revelle (Revelle), 

and a seismic airgun array and 

hydrophone streamer to collect seismic 

data in the Southwest Pacific Ocean, 

East of New Zealand. SIO plans to use 

conventional low-energy, seismic 

methodology to perform marine-based 

studies in the Southwest Pacific Ocean 

(see Figure 1 of the IHA application). 

The studies would involve a low-energy 

seismic survey and heat-flow 

measurements from the seafloor to meet 

a number of research goals. In addition 

to the proposed operations of the 

seismic airgun array and hydrophone 

streamer, SIO intends to operate two 

additional acoustical data acquisition 

systems—a multi-beam echosounder 

and sub-bottom profiler continuously 

throughout the low-energy seismic 

survey. 

Acoustic stimuli (i.e., increased 

underwater sound) generated during the 

operation of the seismic airgun array 

have the potential to cause behavioral 

disturbance for marine mammals in the 

proposed study area. This is the 

principal means of marine mammal 

taking associated with these activities, 

and SIO have requested an 

authorization to take 32 species of 

marine mammals by Level B 

harassment. Take is not expected to 

result from the use of the multi-beam 

echosounder and sub-bottom profiler, as 

the brief exposure of marine mammals 

to one pulse, or small numbers of 

signals, to be generated by these 

instruments in this particular case is not 

likely to result in the harassment of 

marine mammals. Also, NMFS does not 

expect take to result from collision with 

the source vessel because it is a single 

vessel moving at a relatively slow, 

constant cruise speed of 5 knots ([kts]; 

9.3 kilometers per hour [km/hr]; 5.8 

miles per hour [mph]) during seismic 

acquisition within the study area, for a 

relatively short period of time 

(approximately 27 operational days). It 

is likely that any marine mammal would 

be able to avoid the vessel. 

Description of the Proposed Specified 

Activity 

Overview 

SIO proposes to use one source vessel, 

the Revelle, a two GI airgun array and 

one hydrophone streamer to conduct the 

conventional seismic survey as part of 

the NSF-funded research project 

‘‘Collaborative Research: The Thermal 

Regime of the Hikurangi Subduction 

Zone and Shallow Slow Slip Events, 

New Zealand.’’ In addition to the 

airguns, SIO intends to conduct a 

bathymetric survey and heat-flow 

measurements at three sites off the 

southwest coast of North Island and 

northeast coast of South Island, New 

Zealand from the Revelle during the 

proposed low-energy seismic survey. 

Proposed Dates and Duration 

The Revelle is expected to depart from 

Auckland, New Zealand on 

approximately May 18, 2015 and arrive 

at Napier, New Zealand on 

approximately June 18, 2015. Airgun 

operations would take approximately 

135 hours in total, and the remainder of 

the time would be spent in transit and 

collecting heat-flow measurements and 

cores. The total distance the Revelle 

would travel in the region to conduct 

the proposed research activities (i.e., 

seismic survey, bathymetric survey, and 

transit to heat-flow measurement 

locations) represents approximately 

2,000 km (1,079.9 nmi). Some minor 

deviation from this schedule is possible, 

depending on logistics and weather 

(e.g., the cruise may depart earlier or be 

extended due to poor weather; or there 

could be additional days of airgun 

operations if collected data are deemed 

to be of substandard quality). 

Proposed Specified Geographic Region 

The proposed project and survey sites 

are located off the southeast coast of 

North Island and northeast coast of the 

South Island, New Zealand in selected 

regions of the Southwest Pacific Ocean. 

The proposed survey sites are located 

between approximately 38.5 to 42.5° 

South and approximately 174 to 180° 

East off the east coast of New Zealand, 

in the EEZ of New Zealand and outside 

of territorial waters (see Figure 1 of the 

IHA Application). Water depths in the 

study area are between approximately 

200 to 3,000 m (656.2 to 9,842.5 ft). The 

proposed low-energy seismic survey 

would be collected in a total of nine 

grids of intersecting lines of two sizes 

(see Figure 1 of the IHA application) at 

exact locations to be determined in the 

field during May to June 2015. Figure 1 

also illustrates the general bathymetry of 

the proposed study area. The proposed 

low-energy seismic survey would be 

within an area of approximately 1,154 

km2 (336.5 nmi2). This estimate is based 

on the maximum number of kilometers 

for the low-energy seismic survey (1,250 

km) multiplied by the area ensonified 

around the planned tracklines (2 x 0.6 

km in intermediate water depths and 

2 x 0.4 km in deep water depths). The 

ensonified area is based on the 

predicted rms radii (m) based on 

modeling and empirical measurements 

(assuming 100% use of the two 45 in3

GI airguns in 100 to 1,000 m or greater 

than 1,000 m water depths), which was 

calculated to be 600 m (1,968.5 ft) or 

400 m (1,312.3 ft). 

BILLING CODE 3510–22–P 

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15062 Federal Register / Vol. 80, No. 54 / Friday, March 20, 2015 / Notices 

BILLING CODE 3510–22–C 

Detailed Description of the Proposed 

Specified Activity 

In support of a research project put 

forward by Oregon State University 

(OSU) and to be funded by NSF, SIO 

proposes to conduct a low-energy 

seismic survey in the Southwest Pacific 

Ocean, East of New Zealand, from May 

to June 2015. In addition to the lowenergy seismic survey, scientific 

research activities would include 

conducting a bathymetric profile survey 

of the seafloor using transducer-based 

instruments such as a multi-beam 

echosounder and sub-bottom profiler; 

and heat-flow measurements from the 

seafloor using various methods and 

equipment at three sites off the 

southeast coast of North Island and 

northeast coast of South Island, New 

Zealand. Water depths in the survey 

area are approximately 200 to 3,000 

meters (m) (656.2 to 9,842.5 feet [ft]). 


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Figure 1. Locations of the proposed low-energy seismic survey and heat-flow probe 

measurement sites east ofNew Zealand, May to June 2015. 
Federal Register / Vol. 80, No. 54 / Friday, March 20, 2015 / Notices 15063 

The proposed low-energy seismic 

survey is scheduled to occur for a total 

of approximately 135 hours over the 

course of the entire cruise, which would 

be for approximately 27 operational 

days in May to June 2015. The proposed 

low-energy seismic survey would be 

conducted during the day (from nautical 

twilight-dawn to nautical twilight-dusk) 

and night, and for up to approximately 

72 hours of continuous operations at a 

time. The operation hours and survey 

length would include equipment 

testing, ramp-up, line changes, and 

repeat coverage. Some minor deviation 

from these dates would be possible, 

depending on logistics and weather. The 

Principal Investigators are Dr. R. N. 

Harris and Dr. A. Trehu of the OSU. 

The proposed surveys would allow 

the development of a process-based 

understanding of the thermal structure 

of the Hikurangi subduction zone, and 

the expansion of this understanding by 

using regional observations of gas 

hydrate-related bottom simulating 

reflections. To achieve the proposed 

project’s goals, the Principal 

Investigators propose to collect lowenergy, high-resolution multi-channel 

system profiles, heat-flow 

measurements, and sediment cores 

along transects seaward and landward 

of the Hikurangi deformation front. 

Heat-flow measurements would be 

made in well-characterized sites, 

increasing the number of publicly 

available heat-flow and thermal 

conductivity measurements from this 

continental margin by two orders of 

magnitude. Seismic survey data would 

be used to produce sediment structural 

maps and seismic velocities to achieve 

the project objectives. Data from 

sediment cores would detect and 

estimate the nature and sources of fluid 

flow through high permeability 

pathways in the overriding plate and 

along the subduction thrust; 

characterize the hydrocarbon and gas 

hydrate system to assist with estimates 

of heat flow from Bottom Simulating 

Reflectors (BSR)s, their role in slope 

stability, and fluid source; and elucidate 

the response of microbes involved in 

carbon cycling to changes in methane 

flux. 

The low-energy seismic survey would 

be collected in a total of 9 grids of 

intersecting lines of two sizes (see 

Figure 1 of the IHA application) at exact 

locations to be determined in the field. 

The water depths would be very similar 

to those at the nominal survey locations 

shown in Figure 1 of the IHA 

application. The northern and middle 

sites off the North Island would be the 

primary study areas, and the southern 

site off the South Island would be a 

contingency area that would only be 

surveyed if time permits. SIO’s 

calculations assume that 7 grids at the 

primary areas and two grids at the 

southern site would be surveyed. The 

total trackline distance of the lowenergy seismic survey would be 

approximately 1,250 km (including the 

two South Island contingency sites), 

almost all in water depths greater than 

1,000 m. 

The procedures to be used for the 

survey would be similar to those used 

during previous low-energy seismic 

surveys by SIO and NSF and would use 

conventional seismic methodology. The 

proposed survey would involve one 

source vessel, the Revelle. SIO would 

deploy a two Sercel Generator Injector 

(GI) airgun array (each with a discharge 

volume of 45 in3 [290.3 cm3], in one 

string, with a total volume of 90 in3

[580.6 cm3]) as an energy source, at a 

tow depth of up to 2 m (6.6 ft) below 

the surface (more information on the 

airguns can be found in SIO’s IHA 

application). The airguns in the array 

would be spaced approximately 8 m 

(26.2 ft) apart and 21 m (68.9 ft) astern 

of the vessel. The receiving system 

would consist of one 600 m (1,968.5 ft) 

long, 48-channel hydrophone 

streamer(s) towed behind the vessel. 

Data acquisition is planned along a 

series of predetermined lines, almost all 

(approximately 95%) of which would be 

in water depths greater than 1,000 m. As 

the GI airguns are towed along the 

survey lines, the hydrophone streamer 

would receive the returning acoustic 

signals and transfer the data to the 

onboard processing system. The seismic 

surveys would be conducted while the 

heat-flow probe is being recharged. All 

planned seismic data acquisition 

activities would be conducted by 

technicians provided by SIO, with 

onboard assistance by the scientists who 

have proposed the study. The vessel 

would be self-contained, and the crew 

would live aboard the vessel for the 

entire cruise. 

The planned seismic survey 

(including equipment testing, start-up, 

line changes, repeat coverage of any 

areas, and equipment recovery) would 

consist of approximately 1,250 

kilometers (km) (674.9 nautical miles 

[nmi]) of transect lines (including turns) 

in the study area in the Southwest 

Pacific Ocean (see Figures 1 of the IHA 

application). Approximately 95% of the 

low-energy seismic survey would occur 

in water depths greater than 1,000 m. In 

addition to the operation of the airgun 

array and heat-flow measurements, a 

multi-beam echosounder and a subbottom profiler would also likely be 

operated from the Revelle continuously 

throughout the cruise. There would be 

additional airgun operations associated 

with equipment testing, ramp-up, and 

possible line changes or repeat coverage 

of any areas where initial data quality is 

sub-standard. In SIO’s estimated take 

calculations, 25% has been added for 

those additional operations. 

TABLE 1—PROPOSED LOW-ENERGY SEISMIC SURVEY ACTIVITIES IN THE SOUTHWEST PACIFIC OCEAN, EAST OF NEW

ZEALAND

Survey length 

(km) 

Total duration 

(hr) 1 Airgun array total volume Time between airgun shots 

(distance) 

Streamer length 

(m) 

1,250 (674.9 nmi) ...... ∼135 2 × 45 = 90 in3 (2 × 1474.8 cm3) ....... 6 to 10 seconds (18.5 to 31 m or 

60.7 to 101.7 ft).

600 (1,968.5 ft) 

1Airgun operations are planned for no more than approximately 72 continuous hours at a time. 

Vessel Specifications 

The Revelle, a research vessel owned 

by the U.S. Navy and operated by SIO 

of the University of California San 

Diego, would tow the two GI airgun 

array, as well as the hydrophone 

streamer. When the Revelle is towing 

the airgun array and the relatively short 

hydrophone streamer, the turning rate of 

the vessel while the gear is deployed is 

approximately 20 degrees per minute, 

which is much higher than the limit of 

5 degrees per minute for a seismic 

vessel towing a streamer of more typical 

length (much greater than 1 km [0.5 

nmi]). Thus, the maneuverability of the 

vessel would not be limited much 

during operations with the streamer. 

The U.S.-flagged vessel, built in 1996, 

has a length of 83 m (272.3 ft); a beam 

of 16.0 m (52.5 ft); a maximum draft of 

5.2 m (19.5 ft); and a gross tonnage of 

3,180. The ship is powered by two 3,000 

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horsepower (hp) Propulsion General 

Electric motors) and a 1,180 hp 

azimuthing jet bowthruster. The GI 

airgun compressor onboard the vessel is 

manufactured by Price Air Compressors. 

The Revelle’s operation speed during 

seismic acquisition is typically 

approximately 9.3 km/hr (5 kts) (varying 

between 7.4 to 11.1 km/hr [4 to 6 kts]). 

When not towing seismic survey gear, 

the Revelle typically cruises at 22.2 to 

23.1 km/hr (12 to 12.5 kts) and has a 

maximum speed of 27.8 km/hr (15 kts). 

The Revelle has an operating range of 

approximately 27,780 km (15,000 nmi) 

(the distance the vessel can travel 

without refueling), which is 

approximately 70 to 75 days. The vessel 

can accommodate 37 scientists and 22 

crew members. 

The vessel also has two observation 

station locations from which Protected 

Species Observers (PSO) would watch 

for marine mammals before and during 

the proposed airgun operations on the 

Revelle. Observing stations would be at 

the 02 level, with a PSO’s eye level 

approximately 10.4 m (34 ft) above sea 

level—one forward on the 02 deck 

commanding a forward-centered, 

approximately 240° view around the 

vessel, and one atop the aft hangar, with 

an aft-centered view that includes the 

radii around the airguns. The eyes on 

the bridge watch would be at a height 

of approximately 15 m (49 ft); PSOs 

would work on the enclosed bridge and 

adjoining aft steering station during any 

inclement weather. More details of the 

Revelle can be found in the IHA 

application and online at: https://

scripps.ucsd.edu/ships/revelle. 

Acoustic Source Specifications— 

Seismic Airguns 

The Revelle would deploy an airgun 

array, consisting of two 45 in3 Sercel GI 

airguns as the primary energy source 

and a 600 m streamer(s) containing 

hydrophones. The airgun array would 

have a supply firing pressure of 1,750 

pounds per square inch (psi). Seismic 

pulses for the GI airguns would be 

emitted at intervals of approximately 6 

to 10 seconds. There would be a 

maximum of approximately 360 shots 

per hour. The number of shots per hour 

would vary based upon the vessel speed 

over ground during the low-energy 

seismic survey. During firing, a brief 

(approximately 20 millisecond) pulse 

sound would be emitted; the airguns 

would be silent during the intervening 

periods. The dominant frequency 

components would range from 0 to 188 

Hertz (Hz). 

The GI airguns would fire the 

compressed air volume in unison in 

‘‘true GI’’ mode. The GI airguns would 

be used in ‘‘true GI’’ mode, that is, the 

volume of the injector chamber (I) (105 

in3 [1721 cm3]) of each GI airgun is 

greater to that of its generator chamber 

(G) (45 in3 [737 cm3]) for each airgun. 

The generator chamber of each GI airgun 

(45 in3) would be the primary source 

and the one responsible for introducing 

the sound pulse into the ocean. The 

larger (105 in3) injector chamber injects 

air into the previously-generated bubble 

to maintain its shape, and would not 

introduce more sound into the water. 

The two GI airguns would be spaced 

approximately 8 m (26.2 ft) apart, sideby-side, 21 m (68.9 ft) behind the 

Revelle, at a depth of up to 2 m during 

the low-energy seismic survey. 

The Nucleus modeling software used 

at Lamont-Doherty Earth Observatory of 

Columbia University (L–DEO) does not 

include GI airguns as part of its airgun 

library, however signatures and 

mitigation models have been obtained 

for two 45 in3 G airguns that are close 

approximations. For the two 45 in3

airgun array, the source output 

(downward) is 230.6 dB re 1 mPam 0-topeak and 235.8 dB re 1 mPam for peakto-peak. The dominant frequency range 

would be 0 to 188 Hz for a pair of GI 

airguns towed at 2 m depth. 

During the low-energy seismic survey, 

the vessel would attempt to maintain a 

constant cruise speed of approximately 

5 knots. The airguns would operate 

continuously for no more than 

approximately 72 hours at a time based 

on operational constraints. The total 

duration of the airgun operations would 

not exceed 135 hours. The relatively 

short, 48-channel hydrophone streamer 

would provide operational flexibility to 

allow the low-energy seismic survey to 

proceed along the designated cruise 

tracklines. The design of the seismic 

equipment is to achieve high-resolution 

images with the ability to correlate to 

the ultra-high frequency sub-bottom 

profiling data and provide crosssectional views to pair with the seafloor 

bathymetry. 

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-to-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 downward-directed 

source levels of the airgun arrays used 

by SIO on the Revelle do not represent 

actual sound levels that can be 

measured at any location in the water. 

Rather, they represent the level that 

would be found 1 m (3.3 ft) from a 

hypothetical point source emitting the 

same total amount of sound as is 

emitted by the combined GI airguns. 

The actual received level at any location 

in the water near the GI airguns would 

not exceed the source level of the 

strongest individual source. In this case, 

that would be about 224.6 dB re 1 mPam 

peak or 229.8 dB re 1 mPam peak-topeak for the two 45 in3 airgun array. 

However, the difference between rms 

and peak or peak-to-peak values for a 

given pulse depends on the frequency 

content and duration of the pulse, 

among other factors. Actual levels 

experienced by any organism more than 

1 m from either GI airgun would be 

significantly lower. 

Accordingly, L–DEO has predicted 

and modeled the received sound levels 

in relation to distance and direction 

from the two GI airgun array. These are 

the nominal source levels applicable to 

downward propagation. A detailed 

description of L–DEO’s modeling for 

this survey’s marine seismic source 

arrays for protected species mitigation is 

provided in the ‘‘Programmatic 

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Environmental Impact Statement/

Overseas Environmental Impact 

Statement prepared for Marine Seismic 

Research that is funded by the National 

Science Foundation and conducted by 

the U.S. Geological Survey’’ (NSF/USGS 

PEIS, 2011). The NSF/USGS PEIS 

discusses the characteristics of the 

airgun pulses. NMFS refers the 

reviewers to that document for 

additional information. 

Predicted Sound Levels for the Airguns 

To estimate takes and determine 

mitigation (i.e., buffer and exclusion) 

zones for the airgun array to be used, 

received sound levels have been 

modeled by L–DEO for a number of 

airgun configurations, including two 45 

in3 G airguns, in relation to distance and 

direction from the airguns (see Figure 2 

of the IHA application). The model does 

not allow for bottom interactions, and is 

most directly applicable to deep water. 

Because the model results are for G 

airguns, which have more energy than 

GI airguns of the same size, those 

distances overestimate (by 

approximately 10%) the distances for 

the two 45 in3 GI airguns. Although the 

distances are overestimated, no 

adjustments for this have been made to 

the radii distances in Table 2 (below). 

Based on the modeling, estimates of the 

maximum distances from the GI airguns 

where sound levels of 190, 180, and 160 

dB re 1 mPa (rms) are predicted to be 

received in intermediate and deep water 

are shown in Table 2 (see Table 1 of the 

IHA application). 

Empirical data concerning the 190, 

180, and 160 dB (rms) distances were 

acquired for various airgun arrays based 

on measurements during the acoustic 

verification studies conducted by L– 

DEO in the northern Gulf of Mexico 

(GOM) in 2003 (Tolstoy et al., 2004) and 

2007 to 2008 (Tolstoy et al., 2009; 

Diebold et al., 2010). Results of the 18 

and 36 airgun array are not relevant for 

the two GI airguns to be used in the 

proposed low-energy seismic survey 

because the airgun arrays are not the 

same size or volume. The empirical data 

for the 6, 10, 12, and 20 airgun arrays 

indicate that, for deep water, the L–DEO 

model tends to overestimate the 

received sound levels at a given 

distance (Tolstoy et al., 2004). For the 

two G airgun array, measurements were 

obtained only in shallow water. When 

compared to measurements in acquired 

in deep water, mitigation radii provided 

by the L–DEO model for the proposed 

airgun operations were found to be 

conservative. The acoustic verification 

surveys also showed that distances to 

given received levels vary with water 

depth; these are larger in shallow water, 

while intermediate/slope environments 

show characteristics intermediate 

between those of shallow water and 

those of deep water environments, and 

documented the influence of a sloping 

seafloor. The only measurements 

obtained for intermediate depths during 

either survey were for the 36-airgun 

array in 2007 to 2008 (Diebold et al., 

2010). Following results obtained at this 

site and earlier practice, a correction 

factor of 1.5, irrespective of distance to 

the airgun array, is used to derive 

intermediate-water radii from modeled 

deep-water radii. 

Measurements were not made for a 

two GI airgun array in intermediate and 

deep water; however, SIO proposes to 

use the buffer and exclusion zones 

predicted by L–DEO’s model for the 

proposed GI airgun operations in 

intermediate and deep water, although 

they are likely conservative given the 

empirical results for the other arrays. 

Using the L–DEO model, Table 2 

(below) shows the distances at which 

three rms sound levels are expected to 

be received from the two GI airguns. 

The 160 dB re 1 mPam (rms) isopleth is 

the threshold specified by NMFS for 

potential Level B (behavioral) 

harassment from impulsive noise for 

both cetaceans and pinnipeds. The 180 

and 190 dB re 1 mPam (rms) isopleths 

are the thresholds currently used to 

estimate potential Level A harassment 

as specified by NMFS (2000) and are 

applicable to cetaceans and pinnipeds, 

respectively. Table 2 summarizes the 

predicted distances at which sound 

levels (160, 180, and 190 dB [rms]) are 

expected to be received from the two 

airgun array (each 45 in3) operating in 

intermediate water (100 to 1,000 m 

[328.1 to 3,280 ft]) and deep water 

(>1,000 m) depths. 

TABLE 2—PREDICTED AND MODELED (TWO 45 IN3 GI AIRGUN ARRAY) DISTANCES TO WHICH SOUND LEVELS ≥160, 180, 

AND 190 dB RE 1 μPA (rms) COULD BE RECEIVED IN INTERMEDIATE AND DEEP WATER DURING THE PROPOSED

LOW-ENERGY SEISMIC SURVEY IN THE SOUTHWEST PACIFIC OCEAN, EAST OF NEW ZEALAND, MAY TO JUNE 2015 

Source and total volume Tow depth 

(m) Water depth (m) 

Predicted RMS radii distances (m) for 2 GI airgun array 

160 dB 180 dB 190 dB 

Two 45 in3 GI Airguns 

(90 in3).

2 Intermediate (100 to 

1,000).

600 (1,968.5 

ft) 

100 (328.1 ft) 15 (49.2 ft) *100 would be used for pinnipeds 

as described in NSF/USGS PEIS* 

Two 45 in3 GI Airguns 

(90 in3).

2 Deep (>1,000) ............. 400 (1,312.3 

ft) 

100 (328.1 

m) 

10 (32.8 ft) *100 would be used for pinnipeds 

as described in NSF/USGS PEIS* 

Based on the NSF/USGS PEIS and 

Record of Decision, for situations which 

incidental take of marine mammals is 

anticipated, proposed exclusion zones 

of 100 m for cetaceans and pinnipeds 

for all low-energy acoustic sources in 

water depths greater than 100 m would 

be implemented. 

NMFS expects that acoustic stimuli 

resulting from the proposed operation of 

the two GI airgun array has the potential 

to harass marine mammals. NMFS does 

not expect that the movement of the 

Revelle, during the conduct of the lowenergy seismic survey, has the potential 

to harass marine mammals because the 

relatively slow operation speed of the 

vessel (approximately 5 kts; 9.3 km/hr; 

5.8 mph) during seismic data 

acquisition should allow marine 

mammals to avoid the vessel. 

Bathymetric Survey 

Along with the low-energy airgun 

operations, two additional geophysical 

(detailed swath bathymetry) 

measurements focused on a specific 

study area within the Southwest Pacific 

Ocean would be made using hullmounted sonar system instruments from 

the Revelle for operational and 

navigational purposes. The ocean floor 

would be mapped with the Kongsberg 

EM 122 multi-beam echosounder and a 

Knudsen Chirp 3260 sub-bottom 

profiler. During bathymetric survey 

operations, when the vessel is not 

towing seismic equipment, its average 

speed would be approximately 10.1 kts 

(18.8 km/hr). In cases where higher 

resolution bathymetric data is sought, 

the average speed may be as low as 5 kts 

(9.3 km/hr). These sound sources would 

be operated continuously from the 

Revelle throughout the cruise. Operating 

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15066 Federal Register / Vol. 80, No. 54 / Friday, March 20, 2015 / Notices 

characteristics for the instruments to be 

used are described below. 

Multi-Beam Echosounder (Kongsberg 

EM 122)—The hull-mounted multibeam sonar would be operated 

continuously during the cruise to map 

the ocean floor. This instrument would 

operate at a frequency of 10.5 to 13 

(usually 12) kilohertz (kHz) and would 

be hull-mounted. The transmitting 

beamwidth would be 1 or 2° fore to aft 

and 150° athwartship (cross-track). The 

estimated maximum source energy level 

would be 242 dB re 1mPa (rms). Each 

‘ping’ of eight (in water greater than 

1,000 m or four (in water less than 1,000 

m) successive fan-shaped transmissions, 

each ensonifying a sector that extends 1° 

fore to aft. Continuous-wave signals 

increase from 2 to 15 milliseconds (ms) 

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

and FM chirp signals up to 100 ms long 

would be used in water greater than 

2,600 m. The successive transmission 

span an overall cross-track angular 

extent of about 150°, with 2 ms gaps 

between the pings for successive 

sectors. 

Sub-Bottom Profiler—The Revelle 

would operate a Knudsen 3260 subbottom profiler continuously throughout 

the cruise simultaneously to map and 

provide information about the seafloor 

sedimentary features and bottom 

topography that is mapped 

simultaneously with the multi-beam 

echosounder. The beam of the subbottom profiler would be transmitted as 

a 27° cone, directed downward by a 3.5 

kHz transducer in the hull of the 

Revelle. The nominal power output 

would be 10 kilowatt (kW), but the 

actual maximum radiated power would 

be 3 kW or 222 dB (rms). The ping 

duration would be up to 64 ms, and the 

ping interval would be 1 second. A 

common mode of operation is a 

broadcast five pulses at 1 second 

intervals followed by a 5 second pause. 

The sub-bottom profiler would be 

capable of reaching depths of 10,000 m 

(32,808.4 ft). 

Acoustic Locator (Pinger)—A pinger 

would be deployed with certain 

instruments and equipment (e.g., heatflow probe) so these devices can be 

located in the event they become 

detached from their lines. The pinger 

used in the heat-flow measurement 

activities would be the Datasonics 

model BFP–312HP. A pinger typically 

operates at a frequency of 32.8 kHz, 

generates a 5 ms pulse per second (10 

pulses over a 10 second period), and has 

an acoustical output of 210 dB re 1 mPa 

(rms). The pinger would be used during 

heat-flow measurement operations only. 

It would operate continuously during 

each heat-flow probe deployment. Each 

heat-flow probe measurement would 

last approximately 24 hours. 

Heat-Flow Probe Deployment 

Heat-flow measurements would be 

made using a ‘‘violin-bow’’ probe with 

11 thermistors that provides real time 

(analog) telemetry of the thermal 

gradient and in-situ thermal 

conductivity. The heat-flow probe that 

would be used on the Revelle consists 

of a lance 6 centimeter (cm) (2.4 in) in 

diameter and 3.5 m (11.5 ft) long, a 

sensor tube housing thermistors and 

heater wires, and a 560 kg (1,234.6 lb) 

weight stand. The probe would be 

lowered to the bottom, and a 12 kHz 

pinger attached to the wire 

approximately 50 m (164 ft) above the 

instrument would monitor the distance 

between the probe and bottom. The 

probe would be driven into the 

sediment by gravity, and temperatures 

within the sediment would be measured 

with equally spaced thermistors. On 

completion of a measurement, the 

instrument would be hoisted 100 to 500 

m (328.1 to 1,640.4 ft) above the 

sediment, the ship is maneuvered to a 

new position, and the process is 

repeated. Heat-flow measurements can 

generally be made at a rate of 1 to 2 

hours per measurement, approximately 

15 minutes for the actual measurement 

and 45 to 90 minutes to reposition the 

ship and probe. Internal power allows 

20 to 24 measurements during a single 

lowering of the tool, with profiles 

lasting as long as 48 hours. Proposed 

heat-flow measurements would have a 

nominal spacing of 0.5 to 1 km (0.3 to 

0.5 nmi), which would be decreased in 

areas of significant basement relief or of 

large changes in gradient. Heat flow 

transect locations are shown in Figure 1 

of the IHA application, and details of 

the probe and its deployment are given 

in Section (f) of the IHA application. In 

total, approximately 200 heat-flow 

measurements would be made. 

Description of the Marine Mammals in 

the Specified Geographic Area of the 

Proposed Specified Activity 

Few scientific systematic surveys for 

marine mammals have been conducted 

in the waters of New Zealand, and these 

mainly consist of single-species surveys 

in shallow coastal waters (e.g., Dawson 

et al., 2004; Slooten et al., 2004, 2006). 

Large-scale, multi-species marine 

mammal surveys are lacking. Various 

sources for data on sightings in the 

proposed study area were used to 

describe the occurrence of marine 

mammals in the waters of New Zealand, 

such as opportunistic sighting records 

presented in previous reports (including 

the New Zealand Department of 

Conservation marine mammals sighting 

database) considered in evaluating 

potential marine mammals in the 

proposed action area. 

New Zealand is considered a 

‘‘hotspot’’ for marine mammal species 

richness (Kaschner et al., 2011). The 

marine mammals that generally occur in 

the proposed action area belong to three 

taxonomic groups: Mysticetes (baleen 

whales), odontocetes (toothed whales), 

and pinnipeds (seals and sea lions). The 

marine mammal species that could 

potentially occur within the Southwest 

Pacific Ocean in proximity to the 

proposed action area East of New 

Zealand include 30 species of cetaceans 

(21 odontocetes and 9 mysticetes) and 2 

species of pinnipeds (32 total species of 

marine mammals). 

Marine mammal species likely to be 

encountered in the proposed study area 

that are listed as endangered under the 

U.S. Endangered Species Act of 1973 

(ESA; 16 U.S.C. 1531 et seq.), includes 

the southern right (Eubalaena australis), 

humpback (Megaptera novaeangliae), 

sei (Balaenoptera borealis), fin 

(Balaenoptera physalus), blue 

(Balaenoptera musculus), and sperm 

(Physeter macrocephalus) whale. The 

Maui’s dolphin (Cephalorhynchus 

hectori maui) and New Zealand sea lion 

(Phocartos hookeri) are two other 

species are ranked as ‘‘nationally 

critical’’ in New Zealand (Baker et al., 

2010). Maui’s dolphin is only found 

along the west coast of the North Island. 

The northern range of the New Zealand 

sea lion is not expected to extend to the 

proposed study area based on New 

Zealand’s National Aquatic Biodiversity 

Information System (NABIS, 2014) and 

is not considered further. 

In addition to the marine mammal 

species known to occur in the 

Southwest Pacific Ocean off the east 

coast of New Zealand, there are 18 

species of marine mammals (12 cetacean 

and 6 pinniped species) with ranges that 

are known to potentially occur in the 

waters of the proposed study area, but 

they are categorized as ‘‘vagrant’’ under 

the New Zealand Threat Classification 

System (Baker et al., 2010). These 

include: Dwarf sperm whale (Kogia 

sima), Arnoux’s beaked whale 

(Berardius arnouxi), ginkgo-toothed 

beaked whale (Mesoplodon ginkgodens), 

pygmy beaked whale (Mesoplodon 

peruvianis), Type B, C, and D killer 

whale (Orcinus orca), melon-headed 

whale (Peponocephala electra), Risso’s 

dolphin (Grampus griseus), Fraser’s 

dolphin (Lagenodelphis hosei), 

pantropical spotted dolphin (Stenella 

attenuata), striped dolphin (Stenella 

coeruleoalba), rough-toothed dolphin 

(Steno bredanensis), spectacled 

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Federal Register / Vol. 80, No. 54 / Friday, March 20, 2015 / Notices 15067 

porpoise (Phocoena dioptrica), 

Antarctic fur seal (Arctocephalus 

gazelle), Subantarctic fur seal 

(Arctocephalus tropicalis), crabeater 

seal (Lobodon carcinophagus), leopard 

seal (Hydrurga leptonyx), Ross seal 

(Ommatophoca rossi), and Weddell seal 

(Leptonychotes weddellii). According to 

Jefferson et al. (2008), the distributional 

range of Hubb’s beaked whale 

(Mesoplodon carlhubbsi) and True’s 

beaked whale (Mesoplodon mirus) may 

also include New Zealand waters. There 

are no records of Hubb’s beaked whale 

in New Zealand, and only a single 

record of True’s beaked whale, which 

stranded on the west coast of South 

Island in November 2011 (Constantine 

et al., 2014). The spinner dolphin’s 

(Stenella longirostris) range includes 

tropical and subtropical zones 40° North 

to 40° South, but would be considered 

vagrant as well. However, these species 

are not expected to occur where the 

proposed activities would take place. 

These species are not considered further 

in this document. Table 3 (below) 

presents information on the habitat, 

occurrence, distribution, abundance, 

population, and conservation status of 

the species of marine mammals that 

may occur in the proposed study area 

during May to June 2015. 

TABLE 3—THE HABITAT, OCCURRENCE, RANGE, REGIONAL ABUNDANCE, AND CONSERVATION STATUS OF MARINE MAMMALS THAT MAY OCCUR IN OR NEAR THE PROPOSED LOW-ENERGY SEISMIC SURVEY AREA IN THE SOUTHWEST PACIFIC OCEAN, EAST OF NEW ZEALAND

[See text and tables 2 in SIO’s IHA application for further details] 

Species Habitat Occurrence Range Population estimate ESA 1 MMPA2

Mysticetes 

Southern right whale 

(Eubalaena australis).

Coastal, shelf, pelagic.Common ...... Circumpolar 20 to 55° 

South.

8,000 3 to 15,000 4— 

Worldwide 12,000 12— 

Southern Hemisphere 

2,700 12—Sub-Antarctic 

New Zealand.

EN D 

Pygmy right whale 

(Caperea marginata).

Pelagic and coastal.Rare ............ Circumpolar 30 to 55° 

South.

NA ..................................... NL NC 

Humpback whale 

(Megaptera 

novaeangliae).

Pelagic, nearshore 

waters, and 

banks.

Common ...... Cosmopolitan Migratory .... 35,000 to 42,000 3 12— 

Southern Hemisphere.

EN D 

Minke whale (Balaenoptera 

acutorostrata including 

dwarf sub-species).

Pelagic and coastal.Uncommon .. Circumpolar—Southern 

Hemisphere to 65° 

South.

720,0000 to 

750,000 12 14 15—Southern Hemisphere.

NL NC 

Antarctic minke whale 

(Balaenoptera 

bonaerensis).

Pelagic, ice floes, 

coastal.

Uncommon .. 7° South to ice edge (usually 20 to 65° South).720,000 to 

750,000 12 14 15—Southern Hemisphere.

NL NC 

Bryde’s whale 

(Balaenoptera edeni).

Pelagic and coastal.Rare ............ Circumglobal—Tropical 

and Subtropical Zones.

At least 30,000 to 

40,000 3—Worldwide 

21,000 12—Northwestern 

Pacific Ocean 48,109 13.

NL NC 

Sei whale (Balaenoptera 

borealis).

Primarily offshore, 

pelagic.

Uncommon .. Migratory, Feeding Concentration 40 to 50° 

South.

80,000 3—Worldwide 

10,000 14—South of Antarctic Convergence.

EN D 

Fin whale (Balaenoptera 

physalus).

Continental slope, 

pelagic.

Uncommon .. Cosmopolitan, Migratory .. 140,000 3—Worldwide 

15,000 14—South of Antarctic Convergence.

EN D 

Blue whale (Balaenoptera 

musculus; including 

pygmy blue whale 

[Balaenoptera musculus 

brevicauda]).

Pelagic, shelf, 

coastal.

Uncommon .. Migratory Pygmy blue 

whale—North of Antarctic Convergence 55° 

South.

8,000 to 9,000 3—Worldwide 2,300 12—True 

Southern Hemisphere 

1,500 14—Pygmy.

EN D 

Odontocetes 

Sperm whale (Physeter 

macrocephalus).

Pelagic, deep sea Common ...... Cosmopolitan, Migratory ... 360,000 3—Worldwide 

30,000 13—South of Antarctic Convergence.

EN D 

Dwarf sperm whale (Kogia 

sima).

Shelf, Pelagic ....... Vagrant ....... Circumglobal—Tropical 

and Temperate Zones.

NA ..................................... NL NC 

Pygmy sperm whale (Kogia 

breviceps).

Shelf, Pelagic ....... Uncommon .. Circumglobal—Temperate 

Zones.

NA ..................................... NL NC 

Arnoux’s beaked whale 

(Berardius arnuxii).

Pelagic ................. Vagrant ........ Circumpolar in Southern 

Hemisphere, 24 to 78° 

South.

NA ..................................... NL NC 

Cuvier’s beaked whale 

(Ziphius cavirostris).

Pelagic ................. Uncommon .. Cosmopolitan .................... 600,000 14 16 ...................... NL NC 

Southern bottlenose whale 

(Hyperoodon planifrons).

Pelagic ................. Rare ............ Circumpolar—30° South to 

ice edge.

500,000 3—South of Antarctic Convergence 

600,000 14 16.

NL NC 

Shepherd’s beaked whale 

(Tasmacetus shepherdi).

Pelagic ................. Rare ............ Circumpolar—Cold temperate waters Southern 

Hemisphere.

600,000 14 16 ...................... NL NC 

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15068 Federal Register / Vol. 80, No. 54 / Friday, March 20, 2015 / Notices 

TABLE 3—THE HABITAT, OCCURRENCE, RANGE, REGIONAL ABUNDANCE, AND CONSERVATION STATUS OF MARINE MAMMALS THAT MAY OCCUR IN OR NEAR THE PROPOSED LOW-ENERGY SEISMIC SURVEY AREA IN THE SOUTHWEST PACIFIC OCEAN, EAST OF NEW ZEALAND—Continued 

[See text and tables 2 in SIO’s IHA application for further details] 

Species Habitat Occurrence Range Population estimate ESA 1 MMPA2

Andrew’s beaked whale 

(Mesoplodon bowdoini).

Pelagic ................. Rare ............ Circumpolar—temperate 

waters of Southern 

Hemisphere, 32 to 55° 

South.

600,000 14 16 ...................... NL NC 

Blainville’s beaked whale 

(Mesoplodon 

densirostris).

Pelagic ................. Rare ............ Circumglobal—tropical and 

temperate waters.

600,000 14 16 ...................... NL NC 

Ginkgo-toothed beaked 

whale (Mesoplodon 

ginkgodens).

Pelagic ................. Vagrant ....... Tropical and Temperate 

waters—Indo-Pacific 

Ocean.

NA ..................................... NL NC 

Gray’s beaked whale 

(Mesoplodon grayi).

Pelagic ................. Common ...... 30° South to Antarctic 

waters.

600,000 14 16 ...................... NL NC 

Hector’s beaked whale 

(Mesoplodon hectori).

Pelagic ................. Rare ............ Circumpolar—cool temperate waters of Southern Hemisphere.600,000 14 16 ...................... NL NC 

Hubb’s beaked whale 

(Mesoplodon carlhubbsi).

Pelagic ................. Vagrant ....... North Pacific Ocean ......... NA ..................................... NL NC 

Pygmy beaked whale 

(Mesoplodon peruvianis).

Pelagic ................. Vagrant ....... 28° North to 30° South in 

Pacific Ocean.

NA ..................................... NL NC 

Spade-toothed beaked 

whale (Mesoplodon 

traversii).

Pelagic ................. Rare ............ Circumantarctic ................. 600,000 14 16 ...................... NL NC 

Strap-toothed beaked 

whale (Mesoplodon 

layardii).

Pelagic ................. Uncommon .. 30° South to Antarctic 

Convergence.

600,000 14 16 ...................... NL NC 

True’s beaked whale 

(Mesoplodon mirus).

Pelagic ................. Vagrant ........ Anti-tropical in Northern 

and Southern Hemisphere.

NA ..................................... NL NC 

Killer whale (Orcinus orca) Pelagic, shelf, 

coastal, pack 

ice.

Common ...... Cosmopolitan .................... 80,000 3—South of Antarctic Convergence.NL NC 

False killer whale 

(Pseudorca crassidens).

Pelagic, shelf, 

coastal.

Uncommon .. Circumglobal—tropical and 

warmer temperate water.

NA ..................................... NL NC 

Long-finned pilot whale 

(Globicephala melas).

Pelagic, shelf, 

coastal.

Common ...... Circumpolar—19 to 68° 

South in Southern 

Hemisphere.

200,000 3 5 14—South of 

Antarctic Convergence.

NL NC 

Short-finned pilot whale 

(Globicephala 

macrocephalus).

Pelagic, shelf, 

coastal.

Uncommon .. Circumglobal—50° North 

to 40° South.

At least 600,000 3—Worldwide.NL NC 

Melon-headed whale 

(Peponocephala electra).

Pelagic, shelf, 

coastal.

Vagrant ....... Circumglocal—40° North 

to 35° South.

45,000 3—Eastern Tropical 

Pacific Ocean.

NL NC 

Bottlenose dolphin 

(Tursiops truncatus).

Coastal, shelf, offshore.Common ...... 45° North to 45° South ..... At least 614,000 3—Worldwide.NL, *C NC 

Dusky dolphin 

(Lagenorhynchus 

obscurus).

Shelf, slope .......... Common ...... Temperate waters—Southern Hemisphere.12,000 to 20,000 17—New 

Zealand.

NL NC 

Fraser’s dolphin 

(Lagenodelphis hosei).

Pelagic ................. Vagrant ........ Pantropical—30° North to 

30° South.

289,000 3—Eastern Tropical Pacific Ocean.NL NC 

Hector’s dolphin 

(Cephalorhynchus 

hectori; including Maui’s 

dolphin subspecies [C. h. 

maui]).

Nearshore ............ Rare ............ Shallow coastal waters— 

New Zealand (Maui’s 

dolpin—west North Island).

7,400 17 ............................. C NC 

Hourglass dolphin 

(Lagenorhynchus 

cruciger).

Pelagic, ice edge Uncommon .. 33° South to pack ice ....... 144,000 3 to 150,000 14— 

South of Antarctic Convergence.

NL NC 

Pantropical spotted dolphin 

(Stenella attenuata).

Coastal, shelf, 

slope.

Vagrant ........ Circumglobal—40° North 

to 40° South.

At least 2,000,000 3— 

Worldwide.

NL NC 

Spinner dolphin (Stenella 

longirostris).

Mainly nearshore Vagrant ....... Circumglobal—40° North 

to 40° South.

At least 1,200,000 3— 

Worldwide.

NL NC 

Striped dolphin (Stenella 

coeruleoalba).

Off continental 

shelf, convergence zones, 

upwelling.

Vagrant ....... Circumglobal—50 to 40 

South.

At least 1,100,000 3— 

Worldwide.

NL NC 

Risso’s dolphin (Grampus 

griseus).

Slope, Pelagic ...... Vagrant ........ Circumglobal—Tropical 

and Temperate waters.

At least 330,000 3—Worldwide.NL NC 

Rough-toothed dolphin 

(Steno bredanensis).

Pelagic ................. Vagrant ........ Circumglobal—40° North 

to 35° South.

NA ..................................... NL NC 

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Federal Register / Vol. 80, No. 54 / Friday, March 20, 2015 / Notices 15069 

TABLE 3—THE HABITAT, OCCURRENCE, RANGE, REGIONAL ABUNDANCE, AND CONSERVATION STATUS OF MARINE MAMMALS THAT MAY OCCUR IN OR NEAR THE PROPOSED LOW-ENERGY SEISMIC SURVEY AREA IN THE SOUTHWEST PACIFIC OCEAN, EAST OF NEW ZEALAND—Continued 

[See text and tables 2 in SIO’s IHA application for further details] 

Species Habitat Occurrence Range Population estimate ESA 1 MMPA2

Short-beaked common dolphin (Delphinus delphis).Pelagic ................. Common ...... Circumglobal—tropical and 

warm temperate waters.

At least 3,500,000 3— 

Worldwide.

NL NC 

Southern right whale dolphin (Lissodelphis 

peronii).

Pelagic ................. Uncommon .. 12 to 65° South ................ NA ..................................... NL NC 

Spectacled porpoise 

(Phocoena dioptrica).

Coastal, pelagic ... Vagrant ........ Circumpolar—Southern 

Hemisphere.

NA ..................................... NL NC 

Pinnipeds 

Crabeater seal (Lobodon 

carcinophaga).

Coastal, pack ice Vagrant ....... Circumpolar—Antarctic ..... 5,000,000 to 

15,000,000 3 6—Worldwide.

NL NC 

Leopard seal (Hydrurga 

leptonyx).

Pack ice, sub-Antarctic islands.Vagrant ....... Sub-Antarctic islands to 

pack ice.

220,000 to 440,000 3 7— 

Worldwide.

NL NC 

Ross seal (Ommatophoca 

rossii).

Pack ice, smooth 

ice floes, pelagic.

Vagrant ....... Circumpolar—Antarctic ..... 130,000 3 20,000 to 

220,000 11—Worldwide.

NL NC 

Weddell seal 

(Leptonychotes weddellii).

Fast ice, pack ice, 

sub-Antarctic islands.

Vagrant ........ Circumpolar—Southern 

Hemisphere.

500,000 to 1,000,000 3 8— 

Worldwide.

NL NC 

Southern elephant seal 

(Mirounga leonina).

Coastal, pelagic, 

sub-Antarctic 

waters.

Uncommon .. Circumpolar—Antarctic 

Convergence to pack 

ice.

640,000 9 to 650,000 3— 

Worldwide 470,000— 

South Georgia Island 11

607,000 17.

NL NC 

Antarctic fur seal 

(Arctocephalus gazella).

Shelf, rocky habitats.Vagrant ........ Sub-Antarctic islands to 

pack ice edge.

1,600,000 10 to 

3,000,000 3—Worldwide.

NL NC 

New Zealand fur seal 

(Arctocephalus forsteri).

Rocky habitats, 

sub-Antarctic islands.

Common ...... North and South Islands, 

New Zealand Southern 

and Western Australia.

135,000 3—Worldwide 

50,000 to 100,000 18— 

New Zealand.

NL NC 

Subantarctic fur seal 

(Arctocephalus tropicalis).

Shelf, rocky habitats.Vagrant ........ Subtropical front to subAntarctic islands and 

Antarctica.

Greater than 310,000 3— 

Worldwide.

NL NC 

New Zealand sea lion 

(Phocarctos hookeri).

Shelf, rocky habitats.Rare ............ Sub-Antarctic islands 

south of New Zealand.

12,500 3 ............................. NL NC 

NA = Not available or not assessed. 

* Fjordland population. 

1 U.S. Endangered Species Act: EN = Endangered, T = Threatened, DL = Delisted, NL = Not listed, C = Candidate. 

2 U.S. Marine Mammal Protection Act: D = Depleted, S = Strategic, NC = Not Classified. 

3 Jefferson et al., 2008. 4Kenney, 2009. 

5Olson, 2009. 

6Bengston, 2009. 

7 Rogers, 2009. 

8Thomas and Terhune, 2009. 

9 Hindell and Perrin, 2009. 

10Arnould, 2009. 11Academic Press, 2009. 12 IWC, 2014. 13 IWC, 1981. 14Boyd, 2002. 15 Dwarf and Antarctic minke whale combined. 16All Antarctic beaked whales combined. 17 New Zealand Department of Conservation. 18Suisted and Neale, 2004. 

Refer to sections 3 and 4 of SIO’s IHA 

application for detailed information 

regarding the abundance and 

distribution, population status, and life 

history and behavior of these marine 

mammal species and their occurrence in 

the proposed action area. The IHA 

application also presents how SIO 

calculated the estimated densities for 

the marine mammals in the proposed 

study 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 of the Proposed 

Specified Activity on Marine Mammals 

This section includes a summary and 

discussion of the ways that the types of 

stressors associated with the specified 

activity (e.g., seismic airgun operation, 

vessel movement, and gear deployment) 

have been thought to impact marine 

mammals. This discussion may also 

include reactions that we consider to 

rise to the level of a take and those that 

we do not consider to rise to the level 

of take (for example, with acoustics, we 

may include a discussion of studies that 

showed animals not reacting at all to 

sound or exhibiting barely measureable 

avoidance). This section is intended as 

a background of potential effects and 

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does not consider either the specific 

manner in which this activity would be 

carried out or the mitigation that would 

be implemented, and how either of 

those would shape the anticipated 

impacts from this specific activity. The 

‘‘Estimated Take by Incidental 

Harassment’’ section later in this 

document would include a quantitative 

analysis of the number of individuals 

that are expected to be taken by this 

activity. The ‘‘Negligible Impact 

Analysis’’ section will include the 

analysis of how this specific activity 

will impact marine mammals and will 

consider the content of this section, the 

‘‘Estimated Take by Incidental 

Harassment’’ section, the ‘‘Proposed 

Mitigation’’ section, and the 

‘‘Anticipated Effects on Marine Mammal 

Habitat’’ section to draw conclusions 

regarding the likely impacts of this 

activity on the reproductive success or 

survivorship of individuals and from 

that on the affected marine mammal 

populations or stocks. 

When considering the influence of 

various kinds of sound on the marine 

environment, it is necessary to 

understand that different kinds of 

marine life are sensitive to different 

frequencies of sound. Based on available 

behavioral data, audiograms have been 

derived using auditory evoked 

potentials, anatomical modeling, and 

other data, Southall et al. (2007) 

designate ‘‘functional hearing groups’’ 

for marine mammals and estimate the 

lower and upper frequencies of 

functional hearing of the groups. The 

functional groups and the associated 

frequencies are indicated below (though 

animals are less sensitive to sounds at 

the outer edge of their functional range 

and most sensitive to sounds of 

frequencies within a smaller range 

somewhere in the middle of their 

functional hearing range): 

• Low-frequency cetaceans (13 

species of mysticetes): Functional 

hearing is estimated to occur between 

approximately 7 Hz and 30 kHz; 

• Mid-frequency cetaceans (32 

species of dolphins, six species of larger 

toothed whales, and 19 species of 

beaked and bottlenose whales): 

Functional hearing is estimated to occur 

between approximately 150 Hz and 160 

kHz; 

• High-frequency cetaceans (eight 

species of true porpoises, six species of 

river dolphins, Kogia spp., the 

franciscana [Pontoporia blainvillei], and 

four species of cephalorhynchids): 

Functional hearing is estimated to occur 

between approximately 200 Hz and 180 

kHz; and 

• Phocid pinnipeds in water: 

Functional hearing is estimated to occur 

between approximately 75 Hz and 100 

kHz; 

• Otariid pinnipeds in water: 

Functional hearing is estimated to occur 

between approximately 100 Hz and 40 

kHz. 

As mentioned previously in this 

document, 32 marine mammal species 

(30 cetacean and 2 pinniped species) are 

likely to occur in the proposed lowenergy seismic survey area. Of the 30 

cetacean species likely to occur in SIO’s 

proposed action area, 9 are classified as 

low-frequency cetaceans (southern right, 

pygmy right, humpback, minke, 

Antarctic minke, Bryde’s, sei, fin, and 

blue whale), 20 are classified as midfrequency cetaceans (sperm, Cuvier’s 

beaked, Shepherd’s beaked, southern 

bottlenose, Andrew’s beaked, 

Blainville’s beaked, Gray’s beaked, 

Hector’s beaked, spade-toothed beaked, 

strap-toothed beaked, killer, false killer, 

long-finned pilot, and short-finned pilot 

whale, and bottlenose, dusky, Hector’s, 

hourglass, short-beaked common, and 

southern right whale dolphin), and 1 is 

classified as high-frequency cetaceans 

(pygmy sperm whale) (Southall et al., 

2007). Of the 2 pinniped species likely 

to occur in SIO’s proposed action area, 

1 is classified as phocid (southern 

elephant seal) and 1 is classified as 

otariid (New Zealand fur seal) (Southall 

et al., 2007). A species functional 

hearing group is a consideration when 

we analyze the effects of exposure to 

sound on marine mammals. 

Acoustic stimuli generated by the 

operation of the airguns, which 

introduce sound into the marine 

environment, have the potential to 

cause Level B harassment of marine 

mammals in the proposed study 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 hearing 

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; Le Prell, 2012). 

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. A more 

comprehensive review of these issues 

can be found in the NSF/USGS PEIS 

(2011) and L–DEO’s ‘‘Final 

Environmental Assessment of a Marine 

Geophysical Survey by the R/V Marcus 

G. Langseth in the Atlantic Ocean off 

Cape Hatteras, September to October 

2014.’’ 

Tolerance 

Richardson et al. (1995) defines 

tolerance as the occurrence of marine 

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 (Nieukirk 

et al., 2012). Several studies have shown 

that marine mammals at distances more 

than a few kilometers from operating 

seismic vessels often show no apparent 

response. That is often true even in 

cases when the pulsed sounds must be 

readily audible to the animals based on 

measured received levels and the 

hearing sensitivity of the marine 

mammal group. Although various 

baleen whales and toothed whales, and 

(less frequently) pinnipeds have been 

shown to react behaviorally to airgun 

pulses under some conditions, at other 

times marine mammals of all three types 

have shown no overt reactions. The 

relative responsiveness of baleen and 

toothed whales are quite variable. 

Masking 

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). 

The airguns for the proposed lowenergy seismic survey have dominant 

frequency components of 0 to 188 Hz. 

This frequency range fully overlaps the 

lower part of the frequency range of 

odontocete calls and/or functional 

hearing (full range about 150 Hz to 180 

kHz). Airguns also produce a small 

portion of their sound at mid and high 

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frequencies that overlap most, if not all, 

frequencies produced by odontocetes. 

While it is assumed that mysticetes can 

detect acoustic impulses from airguns 

and vessel sounds (Richardson et al., 

1995a), sub-bottom profilers, and most 

of the multi-beam echosounders would 

likely be detectable by some mysticetes 

based on presumed mysticete hearing 

sensitivity. Odontocetes are presumably 

more sensitive to mid to high 

frequencies produced by the multi-beam 

echosounders and sub-bottom profilers 

than to the dominant low frequencies 

produced by the airguns and vessel. A 

more comprehensive review of the 

relevant background information for 

odontocetes appears in Section 3.6.4.3, 

Section 3.7.4.3 and Appendix E of the 

NSF/USGS PEIS (2011). 

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. 

Situations with prolonged strong 

reverberation are infrequent. However, 

it is common for reverberation to cause 

some lesser degree of elevation of the 

background level between airgun pulses 

(Gedamke, 2011; Guerra et al., 2011, 

2013), and this weaker reverberation 

presumably reduces the detection range 

of calls and other natural sound to some 

degree. Guerra et al. (2013) reported that 

ambient noise levels between seismic 

pulses were elevated because of 

reverberation at ranges of 50 km (27 

nmi) from the seismic source. Based on 

measurements in deep water of the 

Southern Ocean, Gedamke (2011) 

estimated that the slight elevation of 

background levels during intervals 

between pulses reduced blue and fin 

whale communication space by as much 

as 36 to 51% when a seismic survey was 

operating 450 to 2,800 km (243 to 

1,511.9 nmi) away. Based on 

preliminary modeling, Wittekind et al. 

(2013) reported that airgun sounds 

could reduce the communication range 

of blue and fin whales 2,000 km (1,079.9 

nmi) from the seismic source. Klinck et 

al. (2012) also found reverberation 

effects between pulses. Nieukirk et al. 

(2012) and Blackwell et al. (2013) noted 

the potential for masking effects from 

seismic surveys on large whales. 

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, 2012; 

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 North Atlantic 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). Cerchio et al. (2014) 

suggested that the breeding display of 

humpback whales off Angola could 

have been disrupted by seismic sounds, 

as singing activity declined with 

increasing received levels. In addition, 

some cetaceans are known to change 

their calling rates, shift their peak 

frequencies, or otherwise modify their 

vocal behavior in response to airgun 

sounds (Di Iorio and Clark, 2010; 

Castellote et al., 2012; Blackwell et al., 

2013). Di Iorio and Clark (2009) found 

evidence of increased calling by blue 

whales during operations by a lowerenergy seismic source (i.e., sparker). The 

hearing systems of baleen whales are 

undoubtedly more sensitive to lowfrequency sounds than are the ears of 

small odontocetes that have been 

studied directly (MacGillivary et al., 

2013). 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. 

Pinnipeds have the most sensitive 

hearing and/or produce most of their 

sounds in frequencies higher than the 

dominant components of airgun sound, 

but there is some overlap in the 

frequencies of the airgun pulses and the 

calls. However, the intermittent nature 

of airgun pules presumably reduces the 

potential for masking. 

Marine mammals are thought to be 

able to compensate for masking by 

adjusting their acoustic behavior 

through shifting call frequencies, 

increasing call volume, and increasing 

vocalization rates. For example blue 

whales are found to increase call rates 

when exposed to noise from seismic 

surveys in the St. Lawrence Estuary (Di 

Iorio and Clark, 2009). The North 

Atlantic right whales (Eubalaena 

glacialis) exposed to high shipping 

noise increased call frequency (Parks et 

al., 2007), while some humpback 

whales respond to low-frequency active 

sonar playbacks by increasing song 

length (Miller et al., 2000). In general, 

NMFS expects the masking effects of 

seismic pulses to be minor, given the 

normally intermittent nature of seismic 

pulses. 

Behavioral Disturbance 

Marine mammals may behaviorally 

react to sound when exposed to 

anthropogenic noise. 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; Ellison et al., 2012). These 

behavioral reactions are often shown as: 

Changing durations of surfacing and 

dives, number of blows per surfacing, or 

moving direction and/or speed; 

reduced/increased vocal activities; 

changing/cessation of certain behavioral 

activities (such as socializing or 

feeding); visible startle response or 

aggressive behavior (such as tail/fluke 

slapping or jaw clapping); avoidance of 

areas where noise sources are located; 

and/or flight responses (e.g., pinnipeds 

flushing into the water from haul-outs 

or rookeries). 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 (New et al., 2013). 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). 

The biological significance of many of 

these behavioral disturbances is difficult 

to predict, especially if the detected 

disturbances appear minor. However, 

the consequences of behavioral 

modification could be expected to be 

biologically significant if the change 

affects growth, survival, and/or 

reproduction. Some of these significant 

behavioral modifications include: 

• Change in diving/surfacing patterns 

(such as those thought to be causing 

beaked whale stranding due to exposure 

to military mid-frequency tactical 

sonar); 

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• Habitat abandonment due to loss of 

desirable acoustic environment; and 

• Cessation of feeding or social 

interaction. 

The onset of behavioral disturbance 

from anthropogenic noise depends on 

both external factors (characteristics of 

noise sources and their paths) and the 

receiving animals (hearing, motivation, 

experience, demography) and is also 

difficult to predict (Richardson et al., 

1995; Southall et al., 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 sound. In most cases, this 

approach likely overestimates the 

numbers of marine mammals that would 

be affected in some biologicallyimportant manner. 

Baleen Whales—Baleen whales 

generally tend to avoid operating 

airguns, but avoidance radii are quite 

variable (reviewed in Richardson et al., 

1995; Gordon et al., 2004). 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, 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 (Eschrichtius 

robustus) and bowhead (Balaena 

mysticetus) 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 

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

1985; Richardson et al., 1995). 

Studies of gray, bowhead, and 

humpback whales have shown that 

seismic pulses with received levels of 

160 to 170 dB re 1 mPa (rms) 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 4 to 15 km (2.2 

to 8.1 nmi) 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 have shown 

that some species of baleen whales, 

notably bowhead, gray, and humpback 

whales, at times, show strong avoidance 

at received levels lower than 160 to 170 

dB re 1 mPa (rms). 

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 airgun (20 in3) with 

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

the 1998 study, they documented that 

avoidance reactions began at 5 to 8 km 

(2.7 to 4.3 nmi) from the array, and that 

those reactions kept most pods 

approximately 3 to 4 km (1.6 to 2.2 nmi) 

from the operating seismic boat. In the 

2000 study, they noted localized 

displacement during migration of 4 to 5 

km (2.2 to 2.7 nmi) by traveling pods 

and 7 to 12 km (3.8 to 6.5 nmi) by more 

sensitive resting pods of cow-calf 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 (rms) for 

humpback pods containing females, and 

at the mean closest point of approach 

distance the received level was 143 dB 

re 1 mPa (rms). The initial avoidance 

response generally occurred at distances 

of 5 to 8 km (2.7 to 4.3 nmi) from the 

airgun array and 2 km (1.1 nmi) 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 (rms). Studies examining the 

behavioral responses of humpback 

whales to airguns are currently 

underway off eastern Australia (Cato et 

al., 2011, 2012, 2013). 

Data collected by observers during 

several seismic surveys in the 

Northwest Atlantic 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 vs. non-seismic periods 

(Moulton and Holst, 2010). 

Humpback whales on their summer 

feeding grounds in southeast Alaska did 

not exhibit persistent avoidance when 

exposed to seismic pulses from a 1.64– 

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

Some humpbacks seemed ‘‘startled’’ at 

received levels of 150 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 dB re 1 mPa (rms). However, 

Moulton and Holst (2010) reported that 

humpback whales monitored during 

seismic surveys in the Northwest 

Atlantic had lower sighting rates and 

were most often seen swimming away 

from the vessel during seismic periods 

compared with periods when airguns 

were silent. 

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). 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 reactions of right whales 

to seismic surveys. However, Rolland et 

al. (2012) suggested that ship noise 

causes increased stress in right whales; 

they showed that baseline levels of 

stress-related fecal hormone metabolites 

decreased in North Atlantic right whales 

with a 6 dB decrease in underwater 

noise from vessels. Wright et al. (2011) 

also reported that sound could be a 

potential source of stress for marine 

mammals. 

Results from bowhead whales 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 (10.8 to 

16.2 nmi) from a medium-sized airgun 

source (Miller et al., 1999; Richardson et 

al., 1999). However, more recent 

research on bowhead whales 

corroborates earlier evidence that, 

during the summer feeding season, 

bowheads are not as sensitive to seismic 

sources (Miller et al., 2005). 

Nonetheless, Robertson et al. (2013) 

showed that bowheads on their summer 

feeding grounds showed subtle but 

statistically significant changes in 

surfacing-respiration-dive cycles during 

exposure to seismic sounds, including 

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shorter surfacing intervals, shorter 

dives, and decreased number of blows 

per surface interval. 

Bowhead whale calls detected in the 

presence and absence of airgun sounds 

have been studied extensively in the 

Beaufort Sea. Bowheads continue to 

produce calls of the usual types when 

exposed to airgun sounds on their 

summering grounds, although number 

of calls detected are significantly lower 

in the presence than in the absence of 

airgun pulses; Blackwell et al. (2013) 

reported that calling rates in 2007 

declined significantly where received 

SPLs from airgun sounds were 116 to 

129 dB re 1 mPa. Thus, bowhead whales 

in the Beaufort Sea apparently decrease 

their calling rates in response to seismic 

operations, although movement out of 

the area could also contribute to the 

lower call detection rate (Blackwell et 

al., 2013). 

A multivariate analysis of factors 

affecting the distribution of calling 

bowhead whales during their fall 

migration in 2009 noted that the 

southern edge of the distribution of 

calling whales was significantly closer 

to shore with increasing levels of airgun 

sound from a seismic survey a few 

hundred kms to the east of the study 

area (i.e., behind the westwardmigrating whales; McDonald et al., 

2010, 2011). It was not known whether 

this statistical effect represented a 

stronger tendency for quieting of the 

whales farther offshore in deeper water 

upon exposure to airgun sound, or an 

actual inshore displacement of whales. 

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 (rms). 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 versus 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, 2012) reported 

that singing fin whales in the 

Mediterranean moved away from an 

operating airgun array, and their song 

notes had low bandwidths during 

periods with versus without airgun 

sounds. 

Ship-based monitoring studies of 

baleen whales (including blue, fin, sei, 

minke, and humpback whales) in the 

Northwest Atlantic found that overall, 

this group had lower sighting rates 

during seismic vs. non-seismic periods 

(Moulton and Holst, 2010). Baleen 

whales as a group were also seen 

significantly farther from the vessel 

during seismic compared with nonseismic 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). 

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, 2010). 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 

Angliss, 2010). 

Toothed Whales—Little systematic 

information is available about reactions 

of toothed whales to noise pulses. Few 

studies similar to the more extensive 

baleen whale/seismic pulse work 

summarized above have been reported 

for toothed whales. However, 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 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; Barry et al., 2012). 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. Captive bottlenose dolphins 

(Tursiops truncatus) and beluga whales 

(Delphinapterus leucas) exhibited 

changes in behavior when exposed to 

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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. 

Preliminary findings of a monitoring 

study of narwhals (Monodon 

monoceros) in Melville Bay, Greenland 

(summer and fall 2012) showed no 

short-term effects of seismic survey 

activity on narwhal distribution, 

abundance, migration timing, and 

feeding habits (Heide-Jorgensen et al., 

2013a). In addition, there were no 

reported effects on narwhal hunting. 

These findings do not seemingly 

support a suggestion by Heide-Jorgensen 

et al. (2013b) that seismic surveys in 

Baffin Bay may have delayed the 

migration timing of narwhals, thereby 

increasing the risk of narwhals to ice 

entrapment. 

Results of 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 (Phocoenoides dalli) (Stone, 

2003; MacLean and Koski, 2005; Bain 

and Williams, 2006; Stone and Tasker, 

2006). Thompson et al. (2013) reported 

decreased densities and reduced 

acoustic detections of harbor porpoise 

in response to a seismic survey in 

Moray Firth, Scotland, at ranges of 5 to 

10 km (2.7 to 5.4 nmi) (SPLs of 165 to 

172 dB re 1 mPa; sound exposure levels 

(SELs) of 145 to 151 dB mPa2s); however, 

animals returned to the area within a 

few hours. 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. 

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 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, seem to be confined to a 

smaller radius than has been observed 

for the more responsive of some 

mysticetes. However, other data suggest 

that some odontocete species, including 

harbor porpoises, may be more 

responsive than might be expected 

given their poor low-frequency hearing. 

Reactions at longer distances may be 

particularly likely when sound 

propagation conditions are conducive to 

transmission of the higher frequency 

components of airgun sound to the 

animals’ location (DeRuiter et al., 2006; 

Goold and Coates, 2006; Tyack et al., 

2006; Potter et al., 2007). 

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. In the Beaufort Sea, some 

ringed seals avoided an area of 100 m 

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 (Pusa 

hispida) 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 (Phoca 

vitulina) and California sea lions 

(Zalophus californianus) tended to be 

larger when airguns were operating 

(Calambokidis and Osmek, 1998). 

Previous telemetry work suggests that 

avoidance and other behavioral 

reactions by two other species of seals 

to small airgun sources may be stronger 

than evident to date from visual studies 

of pinnipeds reactions to airguns 

(Thompson et al., 1998). 

During seismic exploration off Nova 

Scotia, gray seals (Halichoerus grypus) 

exposed to noise from airguns and 

linear explosive charges did not react 

strongly (J. Parsons in Greene et al., 

1985). Pinnipeds in both water and air, 

sometimes tolerate strong noise pulses 

from non-explosive and explosive 

scaring devices, especially if attracted to 

the area for feeding and reproduction 

(Mate and Harvey, 1987; Reeves et al., 

1996). Thus pinnipeds are expected to 

be rather tolerant of, or habituate to, 

repeated underwater sounds from 

distant seismic sources, at least when 

the animals are strongly attracted to the 

area. 

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, Carder, Schlundt, and 

Ridgway, 2005). Factors that influence 

the amount of threshold shift include 

the amplitude, duration, frequency 

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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 2 (above) presents the 

estimated distances from the Revelle’s 

airguns at which the received energy 

level (per pulse, flat-weighted) would be 

expected to be greater than or equal to 

180 and 190 dB re 1 mPa (rms). 

The established 180 and 190 dB (rms) 

criteria are not considered to be the 

levels above which TTS might occur. 

Rather, they are the received levels 

above which, in the view of a panel of 

bioacoustics specialists convened by 

NMFS before TTS measurements for 

marine mammals started to become 

available, one could not be certain that 

there would be no injurious effects, 

auditory or otherwise, to marine 

mammals. NMFS also assumes that 

cetaceans and pinnipeds exposed to 

levels exceeding 160 dB re 1 mPa (rms) 

may experience Level B harassment. 

For toothed whales, researchers have 

derived TTS information for 

odontocetes from studies on the 

bottlenose dolphin and beluga. The 

experiments show that exposure to a 

single impulse at a received level of 207 

kPa (or 30 psi, peak-to-peak), which is 

equivalent to 228 dB re 1 Pa (peak-topeak), resulted in a 7 and 6 dB TTS in 

the beluga whale at 0.4 and 30 kHz, 

respectively. Thresholds returned to 

within 2 dB of the pre-exposure level 

within 4 minutes of the exposure 

(Finneran et al., 2002). 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 than those of odontocetes 

(Southall et al., 2007). 

In pinnipeds, researchers have not 

measured TTS thresholds associated 

with exposure to brief pulses (single or 

multiple) of underwater sound. 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 

TTS threshold for pulsed sounds has 

been indirectly estimated as being an 

SEL of approximately 171 dB re 1 mPa2·s 

(Southall et al., 2007) which would be 

equivalent to a single pulse with a 

received level of approximately 181 to 

186 dB re 1 mPa (rms), or a series of 

pulses for which the highest rms values 

are a few dB lower. Corresponding 

values for California sea lions and 

northern elephant seals (Mirounga 

angustirostris) are likely to be higher 

(Kastak et al., 2005). 

Additional data are needed to 

determine the received levels at which 

small odontocetes would start to incur 

TTS upon exposure to repeated, lowfrequency pulses of airgun sounds with 

variable received levels. To determine 

how close an airgun array would need 

to approach in order to elicit TTS, one 

would (as a minimum) need to allow for 

the sequence of distances at which 

airgun pulses would occur, and for the 

dependence of received SEL on distance 

in the region of the airgun operation 

(Breitzke and Bohlen, 2010; Laws, 

2012). At the present state of 

knowledge, it can be assumed that the 

effect is directly related to total receive 

energy, although there is recent 

evidence that auditory effects in a given 

animal are not a simple function of 

received acoustic energy. Frequency, 

duration of the exposure and occurrence 

of gaps within the exposure can also 

influence the auditory effect (Finneran 

and Schlundt, 2010, 2011, 2013; 

Finneran et al., 2010a,b; Finneran 2012; 

Ketten, 2012; Kastelein et al., 2013a). 

The assumption that, in marine 

mammals, the occurrence and 

magnitude of TTS is a function of 

cumulative acoustic energy (SEL) is 

probably an oversimplification 

(Finneran, 2012). Popov et al. (2011) 

examined the effects of fatiguing noise 

on the hearing threshold of Yangtze 

finless porpoises (Neophocaena 

phocaenoides) when exposed to 

frequencies of 32 to 128 kHz at 140 to 

160 dB re 1 mPa for 1 to 30 minutes. 

They found that an exposure of higher 

level and shorter duration produced a 

higher TTS than an exposure of equal 

SEL but of lower level and longer 

duration. Kastelein et al. (2012a,b; 

2013b) also reported that the equalenergy model is not valid for predicting 

TTS in harbor porpoises or harbor seals. 

Recent data have shown that the SEL 

required for TTS onset to occur 

increases with intermittent exposures, 

with some auditory recovery during 

silent periods between (Finneran et al., 

2010b; Finneran and Schlundt, 2011). 

Schlundt et al. (2013) reported that the 

potential for seismic surveys using 

airguns to cause auditory effects on 

dolphins could be lower than 

previously thought. Based on behavioral 

tests, Finneran et al. (2011) and 

Schlundt et al. (2013) reported no 

measurable TTS in bottlenose dolphins 

after exposure to 10 impulses from a 

seismic airgun with a cumulative SEL of 

approximately 195 dB re 1 mPa2s; results 

from auditory evoked potential 

measurements were more variable 

(Schlundt et al., 2013). 

Recent studies have also shown that 

the SEL necessary to elicit TTS can 

depend substantially on frequency, with 

susceptibility to TTS increasing with 

increasing frequency above 3 kHz 

(Finneran and Schlundt, 2010, 2011; 

Finneran, 2012). When beluga whales 

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were exposed to fatiguing noise with 

sound levels of 165 dB re 1 mPa for 

durations of 1 to 30 minutes at 

frequencies of 11.2 to 90 kHz, the 

highest TTS with the longest recovery 

time was produced by lower frequencies 

(11.2 and 22.5 kHz); TTS effects also 

gradually increased with prolonged 

exposure time (Popov et al., 2013a). 

Popov et al. (2013b) also reported that 

TTS produced by exposure to a 

fatiguing noise was larger during the 

first session (or naı ̈ve subject state) with 

a beluga whale than TTS that resulted 

from the same sound in subsequent 

sessions (experienced subject state). 

Therefore, Supin et al. (2013) reported 

that SEL may not be a valid metric for 

examining fatiguing sounds on beluga 

whales. Similarly, Nachtigall and Supin 

(2013) reported that false killer whales 

are able to change their hearing 

sensation levels when exposed to loud 

sounds, such as warning signals or 

echolocation sounds. 

It is inappropriate to assume that 

onset of TTS occurs at similar received 

levels in all cetaceans (Southall et al., 

2007). Some cetaceans could incur TTS 

at lower sound exposures than are 

necessary to elicit TTS in the beluga or 

bottlenose dolphin. Based on the best 

available information, Southall et al. 

(2007) recommended a TTS threshold 

for exposure to a single or multiple 

pulses of 183 dB re 1 mPa2s. Tougaard 

et al. (2013) proposed a TTS criterion of 

165 dB re 1 mPa2s for porpoises based 

on data from two recent studies. 

Gedamke et al. (2011), based on 

preliminary simulation modeling that 

attempted to allow for various 

uncertainties in assumptions and 

variability around population means, 

suggested that some baleen whales 

whose closest point of approach to a 

seismic vessel is 1 km or more could 

experience TTS. 

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 (Southall et al., 

2007). 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. 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 6 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. 

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, some odontocetes, 

and some pinnipeds, are especially 

unlikely to incur non-auditory physical 

effects. 

There is no definitive evidence that 

any of these effects occur even for 

marine mammals in close proximity to 

large airgun arrays. However, Gray and 

Van Waerebeek (2011) have suggested a 

cause-effect relationship between a 

seismic survey off Liberia in 2009 and 

the erratic movement, postural 

instability, and akinesia in a pantropical 

spotted dolphin based on spatially and 

temporally close association with the 

airgun array. Additionally, 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 (Castellote and Llorens, 

2013). 

Stranding and Mortality—When a 

living 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.’’ 

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 

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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—The proposed action is 

not a military readiness activity or using 

military active sonar (non-pulse). 

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 mid1980s 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 mid-frequency active 

sonar use in which exposure to sonar is 

believed to have been a contributing 

factor to strandings: Greece (1996); the 

Bahamas (2000); Madeira (2000); Canary 

Islands (2002); and Spain (2006). Refer 

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—Marine mammals close to 

underwater detonations of high 

explosives can be killed or severely 

injured, and the auditory organs are 

especially susceptible to injury (Ketten 

et al., 1993; Ketten, 1995). However, 

explosives are no longer used in marine 

waters for commercial seismic surveys 

or (with rare exceptions) for seismic 

research. These methods have been 

replaced entirely by airguns or related 

non-explosive pulse generators. Airgun 

pulses are less energetic and have 

slower rise times, and there is no 

specific evidence that they can cause 

serious injury, death, or stranding even 

in the case of large airgun arrays. 

However, the association of strandings 

of beaked whales with naval exercises 

involving mid-frequency active sonar 

(non-pulse sound) and, in one case, the 

regional co-occurrence of an L–DEO 

seismic survey (Malakoff, 2002; Cox et 

al., 2006), has raised the possibility that 

beaked whales exposed to strong 

‘‘pulsed’’ sounds could also be 

susceptible to injury and/or behavioral 

reactions that can lead to stranding (e.g., 

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

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 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 deep-diving cetaceans 

exposed to sonar. The evidence for this 

remains circumstantial and associated 

with exposure to naval mid-frequency 

sonar, not seismic surveys (Cox et al., 

2006; Southall et al., 2007). 

Seismic pulses and mid-frequency 

sonar 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 2 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 

expect that the same effects to marine 

mammals would result from military 

sonar and seismic surveys. 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 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 

region. The link between the stranding 

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 high 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 to be used in the proposed 

study and operated by SIO and those 

involved in the naval exercises 

associated with strandings. 

Potential Effects of Other Acoustic 

Devices and Sources 

Multi-Beam Echosounder 

SIO would operate the Kongsberg EM 

122 multi-beam echosounder from the 

source vessel during the planned study. 

Sounds from the multi-beam 

echosounder are very short pulses, 

occurring for approximately 2 to 15 ms 

once every 5 to 20 seconds, depending 

on water depth. Most of the energy in 

the sound pulses emitted by the multibeam echosounder is at frequencies near 

12 kHz (10.5 to 13), and the maximum 

source level is 242 dB re 1 mPa (rms). 

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 

(in water less than 1,000 m) consecutive 

successive fan-shaped transmissions 

(segments) at different cross-track 

angles. Any given marine mammal at 

depth near the trackline would be in the 

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main beam for only one or two of the 

eight 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 would receive 

only limited amounts of pulse energy 

because of the short pulses. Animals 

close to the ship (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 a multi-beam echosounder 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, as well as omnidirectional, 

versus more downward and narrowly 

for the multi-beam echosounder. The 

area of possible influence of the multibeam echosounder 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 SIO’s 

operations, the individual pulses would 

be very short, and a given mammal 

would not receive many of the 

downward-directed pulses as the vessel 

passes by. Possible effects of a multibeam echosounder on marine mammals 

are described below. 

Stranding—In 2013, an International 

Scientific Review Panel investigated a 

2008 mass stranding of approximately 

100 melon-headed whales in a 

Madagascar lagoon system (Southall et 

al., 2013) associated with the use of a 

high-frequency mapping system. The 

report indicated that the use of a 12 kHz 

multi-beam echosounder was the most 

plausible and likely initial behavioral 

trigger of the mass stranding event. This 

was the first time that a relatively highfrequency mapping sonar system has 

been associated with a stranding event. 

However, the report also notes that there 

were several site- and situation-specific 

secondary factors that may have 

contributed to the avoidance responses 

that lead to the eventual entrapment and 

mortality of the whales within the Loza 

Lagoon system (e.g., the survey vessel 

transiting in a north-south direction on 

the shelf break parallel to the shore may 

have trapped the animals between the 

sound source and the shore driving 

them towards the Loza Lagoon). The 

report concluded that for odontocete 

cetaceans that hear well in the 10 to 50 

kHz range, where ambient noise is 

typically quite low, high-power active 

sonars operating in this range may be 

more easily audible and have potential 

effects over larger areas than lowfrequency systems that have more 

typically been considered in terms of 

anthropogenic noise impacts (Southall 

et al., 2013). However, the risk may be 

very low given the extensive use of 

these systems worldwide on a daily 

basis and the lack of direct evidence of 

such responses previously (Southall et 

al., 2013). It is noted that leading 

scientific experts on multi-beam 

echosounders have expressed concerns 

about the independent scientific review 

panel analyses and findings (Bernstein, 

2013). 

Masking—Marine mammal 

communications would not be masked 

appreciably by the multi-beam 

echosounder 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 multi-beam echosounder 

signals (12 kHz) generally do not 

overlap with the predominant 

frequencies in the calls (16 Hz to less 

than 12 kHz), which would avoid any 

significant masking (Richardson et al., 

1995). 

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 (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 

(656.2 ft) (Frankel, 2005). When a 38 

kHz echosounder and a 150 kHz ADCP 

were transmitting during studies in the 

Eastern Tropical Pacific, 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 second 

tonal signals at frequencies similar to 

those that would be emitted by the 

multi-beam echosounder used by SIO, 

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 a multi-beam echosounder. 

Risch et al. (2012) found a reduction 

in humpback whale song in the 

Stellwagen Bank National Marine 

Sanctuary during Ocean Acoustic 

Waveguide Remote Sensing (OAWRS) 

activities that were carried out 

approximately 200 km (108 nmi) away. 

The OAWRS used three frequencymodulated pulses centered at 

frequencies of 415, 734, and 949 Hz 

with received levels in the sanctuary of 

88 to 110 dB re 1 mPa. Deng et al. (2014) 

measured the spectral properties of 

pulses transmitted by three 200 kHz 

echosounders, and found that they 

generated weaker sounds at frequencies 

below the center frequency (90 to 130 

kHz). These sounds are within the 

hearing range of some marine mammals, 

and the authors suggested that they 

could be strong enough to elicit 

behavioral responses within close 

proximity to the sources, although they 

would be well below potentially 

harmful levels. 

Hearing Impairment and Other 

Physical Effects—Given several 

stranding events that have been 

associated with the operation of naval 

sonar in specific circumstances, there is 

concern that mid-frequency sonar 

sounds can cause serious impacts to 

marine mammals (see above). However, 

the multi-beam echosounder proposed 

for use by SIO is quite different than 

sonar used for Navy operations. Pulse 

duration of the multi-beam echosounder 

is very short relative to the naval sonar. 

Also, at any given location, an 

individual marine mammal would be in 

the beam of the multi-beam 

echosounder for much less time, given 

the generally downward orientation of 

the beam and its narrow fore-aft 

beamwidth; Navy sonar often uses nearhorizontally-directed sound and have 

higher duty cycles. Those factors would 

all reduce the sound energy received 

from the multi-beam echosounder rather 

drastically relative to that from naval 

sonar. NMFS believes that the brief 

exposure of marine mammals to one 

pulse, or small numbers of signals, from 

the multi-beam echosounder in this 

particular case is not likely to result in 

the harassment of marine mammals. 

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Sub-Bottom Profiler 

SIO would operate a sub-bottom 

profiler (Knudsen 3260) from the source 

vessel during the proposed study. 

Sounds from the sub-bottom profiler are 

very short pulses, occurring for 1 to 4 

ms once ever second. Most of the energy 

in the sound pulses emitted by the subbottom profiler is at frequencies 3.5 

kHz, and the beam is directed 

downward. The sub-bottom profiler that 

may be used on the Revelle has a 

maximum source level of 204 dB re 1 

mPa. The sonar emits energy in a 27° 

beam from the bottom of the ship. 

Marine mammals that encounter the 

Knudsen 3260 are unlikely to be 

subjected to repeated pulses because of 

the relatively narrow fore–aft width of 

the beam and would receive only 

limited amounts of pulse energy 

because of the short pulses. Animals 

close to the ship (where the beam is 

narrowest) are especially unlikely to be 

ensonified for more than one 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 a sub-bottom profiler emits a 

pulse is small—even for a sub-bottom 

profiler more powerful than that that 

may be on the Revelle. 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 Knudsen 3260; 

and (2) are often directed close to 

horizontally versus more downward for 

the sub-bottom profiler. The area of 

possible influence of the single-beam 

echosounder 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 SIO’s operations, the 

individual pulses would be very short, 

and a given mammal would not receive 

many of the downward-directed pulses 

as the vessel passes by. Possible effects 

of a sub-bottom profiler on marine 

mammals are described below. 

Masking—Marine mammal 

communications would not be masked 

appreciably by the sub-bottom profiler 

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 baleen whales, the sub-bottom 

profiler signals do not overlap with the 

predominant frequencies in the calls (16 

Hz to less than 12 kHz), which would 

avoid any significant masking 

(Richardson et al., 1995). 

Behavioral Responses—Marine 

mammal behavioral reactions to other 

pulsed sound sources are discussed 

above, and responses to the sub-bottom 

profiler are likely to be similar to those 

for other pulsed sources if received at 

the same levels. However, the pulsed 

signals from the sub-bottom profiler are 

considerably weaker than those from the 

multi-beam echosounder. 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 

sub-bottom profiler produces pulse 

levels strong enough to cause hearing 

impairment or other physical injuries 

even in an animal that is (briefly) in a 

position near the source. The subbottom profiler is usually operated 

simultaneously with other higher-power 

acoustic sources, including airguns. 

Many marine mammals will move away 

in response to the approaching higherpower sources or the vessel itself before 

the mammals would be close enough for 

there to be any possibility of effects 

from the less intense sounds from the 

sub-bottom profiler. 

Heat-Flow Probe Deployment 

During heat-flow measurements using 

a probe, the probe is a passive 

instrument and no noise is created by 

the mechanical action of the devices on 

the seafloor is not expected to be 

perceived by nearby fish and other 

marine organisms. Heat-flow 

measurement activities would be highly 

localized and short-term in duration and 

would not be expected to significantly 

interfere with marine mammal behavior. 

The potential direct effects include 

temporary localized disturbance or 

displacement from associated physical 

movement/actions of the operations. 

Additionally, the potential indirect 

effects may consist of very localized and 

transitory/short-term disturbance of 

bottom habitat and associated prey in 

shallow-water areas as a result of heatflow probe measurements. NMFS 

believes that the since the heat-flow 

probe is a passive instrument and has 

no mechanical action, it would not 

likely result in the harassment of marine 

mammals. 

A maximum total of 200 heat-flow 

measurements would be obtained using 

these devices and ranging from 1 to 2 

hours per measurement (for a total of 

approximately 320 hours of operations) 

and it is estimated that the pinger would 

operate continuously during each heatflow probe deployment. The vessel 

would be stationary during heat-flow 

probe deployment and repositioned to 

repeat the process, so the likelihood of 

a collision or entanglement with a 

marine mammal is very low. For the 

heat-flow measurements, the lance is 4.5 

m and would disturb an area 

approximately 8 cm x 20 cm (3.1 in x 

7.9 in). Assuming approximately 200 

heat-flow measurements, the cumulative 

area of seafloor that could be disturbed 

during the proposed study would be 

approximately 32,000 cm2 (4,960 in2). 

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 in 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 (especially low frequency 

specialists) 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 

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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’ reaction 

varied when exposed to vessel noise 

and traffic. In some cases, beluga whales 

exhibited rapid swimming from icebreaking vessels up to 80 km (43.2 nmi) 

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; 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 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 whalewatching 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 

Revelle would be audible to marine 

mammals over a large distance, it is 

unlikely that marine mammals would 

respond behaviorally (in a manner that 

NMFS would consider harassment 

under the MMPA) 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 

Revelle’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 dolphins) 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 

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

SIO’s proposed operation of one 

source vessel for the proposed lowenergy seismic survey is relatively small 

in scale (i.e., a one vessel operation) 

compared to the number of other ships 

(e.g., fishing, tourist, and other vessels) 

transiting at higher speeds in the same 

areas on an annual basis. The 

probability of vessel and marine 

mammal interactions occurring during 

the proposed low-energy seismic survey 

is unlikely due to the Revelle’s slow 

operational speed, which is typically 5 

kts. Outside of seismic operations, the 

Revelle’s cruising speed would be 

approximately 10.1 to 14.5 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 Revelle has a 

number of other advantages for avoiding 

ship strikes as compared to most 

commercial merchant vessels, including 

the following: The Revelle’s bridge and 

other observing stations offer good 

visibility to visually monitor for marine 

mammal presence; PSOs posted during 

operations scan the ocean for marine 

mammals and must report visual alerts 

of marine mammal presence to crew; 

and the PSOs receive extensive training 

that covers the fundamentals of visual 

observing for marine mammals and 

information about marine mammals and 

their identification at sea. 

Entanglement 

Entanglement can occur if wildlife 

becomes immobilized in survey lines, 

cables, nets, or other equipment that is 

moving through the water column. The 

proposed low-energy seismic survey 

would require towing approximately 

one 600 m cable streamers. While 

towing this size of an array carries some 

level of risk of entanglement for marine 

mammals due to the operational nature 

of the activity, entanglement is unlikely. 

Wildlife, especially slow moving 

individuals, such as large whales, have 

a low probability of becoming entangled 

due to slow speed of the survey vessel 

and onboard monitoring efforts. In May 

2011, there was one recorded 

entrapment of an olive ridley sea turtle 

(Lepidochelys olivacea) in the R/V 

Marcus G. Langseth’s barovanes after 

the conclusion of a seismic survey off 

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Costa Rica. There have been cases of 

baleen whales, mostly gray whales 

(Heyning, 1990), becoming entangled in 

fishing lines. The probability for 

entanglement of marine mammals is 

considered very low because of the 

vessel speed and the monitoring efforts 

onboard the survey vessel. Furthermore, 

there has been no history of marine 

mammal entanglement with seismic 

equipment used by the U.S. academic 

research fleet. 

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 impact on affected marine 

mammal species and stocks. 

Anticipated Effects on Marine Mammal 

Habitat 

The proposed low-energy seismic 

survey is not anticipated to have any 

permanent impact on habitats used by 

the marine mammals in the proposed 

study 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 airgun operations during the 

proposed low-energy seismic survey. 

While it is anticipated that the specified 

activity may result in marine mammals 

avoiding certain areas due to brief, 

temporary ensonification, this impact to 

habitat is temporary and was considered 

in further detail earlier in this 

document, as behavioral modification. 

The main impact associated with the 

proposed activity would be temporarily 

elevated noise levels and the associated 

direct effects on marine mammals in 

any particular area of the approximately 

1,154 km 2 proposed study area, 

previously discussed in this notice. 

The next section discusses the 

potential impacts of anthropogenic 

sound sources on common marine 

mammal prey in the proposed study 

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 and invertebrate populations is 

limited. 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 sub-lethal 

injury. Physiological effects involve 

temporary and permanent primary and 

secondary stress responses, such as 

changes in levels of enzymes and 

proteins. Behavioral effects refer to 

temporary and (if they occur) permanent 

changes in exhibited behavior (e.g., 

startle and avoidance behavior). The 

three categories are interrelated in 

complex ways. For example, it is 

possible that certain physiological and 

behavioral changes 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 

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. This makes drawing 

conclusions about impacts on fish 

problematic because, ultimately, the 

most important issues concern effects 

on marine fish populations, their 

viability, and their availability to 

fisheries. 

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 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. 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. There are only two 

known 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 nine 

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 would 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. 

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(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). 

An experiment of the effects of a 

single 700 in 3 airgun was conducted in 

Lake Meade, Nevada (USGS, 1999). The 

data were used in an Environmental 

Assessment of the effects of a marine 

reflection survey of the Lake Meade 

fault system by the National Park 

Service (Paulson et al., 1993, in USGS, 

1999). The airgun was suspended 3.5 m 

(11.5 ft) above a school of threadfin shad 

in Lake Meade and was fired three 

successive times at a 30 second interval. 

Neither surface inspection nor diver 

observations of the water column and 

bottom found any dead fish. 

For a proposed seismic survey in 

Southern California, USGS (1999) 

conducted a review of the literature on 

the effects of airguns on fish and 

fisheries. They reported a 1991 study of 

the Bay Area Fault system from the 

continental shelf to the Sacramento 

River, using a 10 airgun (5,828 in3) 

array. Brezzina and Associates were 

hired by USGS to monitor the effects of 

the surveys and concluded that airgun 

operations were not responsible for the 

death of any of the fish carcasses 

observed. They also concluded that the 

airgun profiling did not appear to alter 

the feeding behavior of sea lions, seals, 

or pelicans observed feeding during the 

seismic surveys. 

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. 

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. 

The former Minerals Management 

Service (MMS, 2005) assessed the 

effects of a proposed seismic survey in 

Cook Inlet. The seismic survey proposed 

using three vessels, each towing two 

four-airgun arrays ranging from 24,580.6 

to 40,967.7 cm3 (1,500 to 2,500 in3). 

MMS noted that the impact to fish 

populations in the survey area and 

adjacent waters would likely be very 

low and temporary. MMS also 

concluded that seismic surveys may 

displace the pelagic fishes from the area 

temporarily when airguns are in use. 

However, fishes displaced and avoiding 

the airgun noise are likely to backfill the 

survey area in minutes to hours after 

cessation of seismic testing. Fishes not 

dispersing from the airgun noise (e.g., 

demersal species) may startle and move 

short distances to avoid airgun 

emissions. 

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 

impinging sound field and not to the 

pressure component (Popper et al., 

2001). 

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. A more detailed review of 

the literature on the effects of seismic 

survey sound on invertebrates is 

provided in Appendix D of NSF/USGS’s 

PEIS (2011). 

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 

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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. Tenera Environmental (2011b) 

reported that Norris and Mohl (1983, 

summarized in Mariyasu et al., 2004) 

observed lethal effects in squid (Loligo 

vulgaris) at levels of 246 to 252 dB after 

3 to 11 minutes. 

Andre et al. (2011) exposed four 

species of cephalopods (Loligo vulgaris, 

Sepia officinalis, Octopus vulgaris, and 

Ilex coindetii), primarily cuttlefish, to 

two hours of continuous 50 to 400 Hz 

sinusoidal wave sweeps at 157+/–5 dB 

re 1 mPa while captive in relatively 

small tanks. They reported 

morphological and ultrastructural 

evidence of massive acoustic trauma 

(i.e., permanent and substantial 

alterations [lesions] of statocyst sensory 

hair cells) to 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 mPa, with peak levels 

at 175 dB re 1 mPa. 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). It was noted 

however, that no behavioral impacts 

were exhibited by crustaceans (Christian 

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

information on the potential effects of 

airguns on fish and invertebrates are 

reviewed in section 3.2.4.3, section 

3.3.4.3, and Appendix D of the NSF/

USGS PEIS (2011). 

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 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 

(where relevant). 

SIO reviewed the following source 

documents and incorporated a suite of 

appropriate mitigation measures into 

the project description. 

(1) Protocols used during previous 

NSF and USGS-funded seismic research 

cruises as approved by NMFS and 

detailed in the ‘‘Final Programmatic 

Environmental Impact Statement/

Overseas Environmental Impact 

Statement for Marine Seismic Research 

Funded by the National Science 

Foundation or Conducted by the U.S. 

Geological Survey;’’ 

(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, SIO 

proposed to implement the following 

mitigation measures for marine 

mammals: 

(1) Proposed exclusion zones around 

the sound source; 

(2) Speed and course alterations; 

(3) Shut-down procedures; and 

(4) Ramp-up procedures. 

Proposed Exclusion Zones—During 

pre-planning of the cruise, the smallest 

airgun array was identified that could be 

used and still meet the geophysical 

scientific objectives. SIO use radii to 

designate exclusion and buffer zones 

and to estimate take for marine 

mammals. Table 2 (presented earlier in 

this document) shows the distances at 

which one would expect to receive three 

sound levels (160, 180, and 190 dB) 

from the two GI airgun array. The 180 

and 190 dB level shut-down criteria are 

applicable to cetaceans and pinnipeds, 

respectively, as specified by NMFS 

(2000) and would be used to establish 

the exclusion and buffer zones. 

Received sound levels have been 

modeled by L–DEO for a number of 

airgun configurations, including two 45 

in 3 Nucleus G airguns, in relation to 

distance and direction from the airguns 

(see Figure 2 of the IHA application). In 

addition, propagation measurements of 

pulses from two GI airguns have been 

reported for shallow water 

(approximately 30 m [98.4 ft] depth) in 

the Gulf of Mexico (Tolstoy et al., 2004). 

However, measurements were not made 

for the two GI airguns in deep water. 

The model does not allow for bottom 

interactions, and is most directly 

applicable to deep water. Based on the 

modeling, estimates of the maximum 

distances from the GI airguns where 

sound levels are predicted to be 190, 

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180, and 160 dB re 1 mPa (rms) in 

intermediate and deep water were 

determined (see Table 2 above). 

Empirical data concerning the 190, 

180, and 160 dB (rms) distances were 

acquired for various airgun arrays based 

on measurements during the acoustic 

verification studies conducted by 

L–DEO in the northern Gulf of Mexico 

in 2003 (Tolstoy et al., 2004) and 2007 

to 2008 (Tolstoy et al., 2009). Results of 

the 18 and 36 airgun arrays are not 

relevant for the two GI airguns to be 

used in the proposed low-energy 

seismic survey because the airgun arrays 

are not the same size or volume. The 

empirical data for the 6, 10, 12, and 20 

airgun arrays indicate that, for deep 

water, the L–DEO model tends to 

overestimate the received sound levels 

at a given distance (Tolstoy et al., 2004). 

Measurements were not made for the 

two GI airgun array in deep water; 

however, SIO proposes to use the safety 

radii predicted by L–DEO’s model for 

the proposed GI airgun operations in 

intermediate and deep water, although 

they are likely conservative given the 

empirical results for the other arrays. 

Based on the modeling data, the 

outputs from the pair of 45 in 3 GI 

airguns proposed to be used during the 

low-energy seismic survey are 

considered a low-energy acoustic source 

in the NSF/USGS PEIS (2011) for 

marine seismic research. A low-energy 

seismic source was defined in the NSF/ 

USGS PEIS as an acoustic source whose 

received level is less than or equal to180 

dB at 100 m (including any single or any 

two GI airguns and a single pair of 

clustered airguns with individual 

volumes of less than or equal to 250 

in 3). The NSF/USGS PEIS also 

established for these low-energy sources 

a standard exclusion zone of 100 m for 

all low-energy sources in water depths 

greater than 100 m. This standard 100 

m exclusion zone would be used during 

the proposed low-energy seismic survey 

using the pair of 45 in 3 GI airguns. The 

180 and 190 dB (rms) radii are the 

current Level A harassment shut-down 

criteria applicable to cetaceans and 

pinnipeds, respectively; these levels 

were used to establish exclusion zones. 

Therefore, the assumed 180 and 190 dB 

radii are 100 m for intermediate and 

deep water. If the PSO detects a marine 

mammal within or about to enter the 

appropriate exclusion zone, the airguns 

would be shut down immediately. 

Speed and Course Alterations—If a 

marine mammal is detected outside the 

exclusion zone and, based on its 

position and direction of travel (relative 

motion), is likely to enter the exclusion 

zone, changes of the vessel’s speed and/ 

or direct course would be considered if 

this does not compromise operational 

safety or damage the deployed 

equipment. This would be done if 

operationally practicable while 

minimizing the effect on the planned 

science objectives. For marine seismic 

surveys towing large streamer arrays, 

course alterations are not typically 

implemented due to the vessel’s limited 

maneuverability. However, the Revelle 

would be towing a relatively short 

hydrophone streamer, so its 

maneuverability during operations with 

the hydrophone streamer would not be 

limited as vessels towing long 

streamers, thus increasing the potential 

to implement course alterations, if 

necessary. After any such speed and/or 

course alteration is begun, the marine 

mammal activities and movements 

relative to the seismic vessel would be 

closely monitored to ensure that the 

marine mammal does not approach 

within the applicable exclusion zone. If 

the marine mammal appears likely to 

enter the exclusion zone, further 

mitigation actions would be taken, 

including further speed and/or course 

alterations, and/or shut-down of the 

airgun(s). Typically, during airgun 

operations, the source vessel is unable 

to change speed or course, and one or 

more alternative mitigation measures 

would need to be implemented. 

Shut-Down Procedures—If a marine 

mammal is detected outside the 

exclusion zone for the airgun(s) but is 

likely to enter the exclusion zone, and 

the vessel’s speed and/or course cannot 

be changed to avoid having the animal 

enter the exclusion zone, SIO would 

shut-down the operating airgun(s) 

before the animal is within the 

exclusion zone. Likewise, if a marine 

mammal is already within the exclusion 

zone when first detected, the airguns 

would be shut-down immediately. 

Following a shut-down, SIO would 

not resume airgun activity until the 

marine mammal has cleared the 

exclusion zone, or until the PSO is 

confident that the animal has left the 

vicinity of the vessel. SIO would 

consider the animal to have cleared the 

exclusion zone if: 

• A PSO has visually observed the 

animal leave the exclusion zone, or 

• A PSO has not sighted the animal 

within the exclusion zone for 15 

minutes for species with shorter dive 

durations (i.e., small odontocetes and 

pinnipeds), or 30 minutes for species 

with longer dive durations (i.e., 

mysticetes and large odontocetes, 

including sperm, dwarf and pygmy 

sperm, killer, and beaked whales). 

Although power-down procedures are 

often standard operating practice for 

seismic surveys, they are not proposed 

to be used during this planned lowenergy seismic survey because powering 

down from two airguns to one airgun 

would make only a small difference in 

the exclusion zone(s) that probably 

would not be enough to allow continued 

one-airgun operations if a marine 

mammal came within the exclusion 

zone for two airguns. 

Ramp-Up Procedures—Ramp-up of an 

airgun array provides a gradual increase 

in sound levels, and involves a stepwise increase in the number and total 

volume of airguns firing until the full 

volume of the airgun array is achieved. 

The purpose of a ramp-up is to ‘‘warn’’ 

marine mammals in the vicinity of the 

airguns and to provide the time for them 

to leave the area, avoiding any potential 

injury or impairment of their hearing 

abilities. SIO would 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. 

SIO proposes that, for the present 

cruise, this period would be 

approximately 15 minutes. SIO, L–DEO, 

USGS, NSF, and ASC have used similar 

periods (approximately 15 minutes) 

during previous low-energy seismic 

surveys. 

Ramp-up would begin with a single 

GI airgun (45 in 3). The second GI airgun 

(45 in 3) would be added after 5 

minutes. During ramp-up, the PSOs 

would monitor the exclusion zone, and 

if marine mammals are sighted, a shutdown would be implemented as though 

both GI airguns were operational. 

If the complete exclusion zone has not 

been visible for at least 30 minutes prior 

to the start of operations in either 

daylight or nighttime, SIO would not 

commence the ramp-up. Given these 

provisions, it is likely that the airgun 

array would not be ramped-up from a 

complete shut-down during low light 

conditions, at night, or in thick fog, (i.e., 

poor visibility conditions) because the 

outer part of the exclusion zone for that 

array would not be visible during those 

conditions. If one airgun has been 

operating, ramp-up to full power would 

be permissible during low light, at 

night, or in poor visibility, on the 

assumption that marine mammals 

would be alerted to the approaching 

seismic vessel by the sounds from the 

single airgun and could move away if 

they choose. SIO would not initiate a 

ramp-up of the airguns if a marine 

mammal is sighted within or near the 

applicable exclusion zones during day 

or night. NMFS refers the reader to 

Figure 2, which presents a flowchart 

representing the ramp-up and shutdown protocols described in this notice. 

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BILLING CODE 3510–22–C 

Proposed Mitigation Conclusions 

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 

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. 

Any mitigation measure(s) prescribed 

by NMFS should be able to accomplish, 

have a reasonable likelihood of 

accomplishing (based on current 

science), or contribute to the 

accomplishment of one or more of the 

general goals listed below: 

(1) Avoidance of minimization of 

injury or death of marine mammals 

wherever possible (goals 2, 3, and 4 may 

contribute to this goal). 

(2) A reduction in the numbers of 

marine mammals (total number or 


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number at biologically important time 

or location) exposed to received levels 

of airguns, or other activities expected 

to result in the take of marine mammals 

(this goal may contribute to 1, above, or 

to reducing harassment takes only). 

(3) A reduction in the number of time 

(total number or number at biologically 

important time or location) individuals 

would be exposed to received levels of 

airguns, or other activities expected to 

result in the take of marine mammals 

(this goal may contribute to 1, above, or 

to reducing harassment takes only). 

(4) A reduction in the intensity of 

exposures (either total number or 

number at biologically important time 

or location) to received levels of airguns, 

or other activities, or other activities 

expected to result in the take of marine 

mammals (this goal may contribute to a, 

above, or to reducing the severity of 

harassment takes only). 

(5) Avoidance or minimization of 

adverse effects to marine mammal 

habitat, paying special attention to the 

food base, activities that block or limit 

passage to or from biologically 

important areas, permanent destruction 

of habitat, or temporary destruction/

disturbance of habitat during a 

biologically important time. 

(6) For monitoring directly related to 

mitigation—an increase in the 

probability of detecting marine 

mammals, thus allowing for more 

effective implementation of the 

mitigation. 

Based on NMFS’s evaluation of the 

applicant’s proposed measures, as well 

as other measures considered by NMFS 

or recommended by the public, NMFS 

has preliminarily determined that the 

proposed mitigation measures provide 

the means of effecting the least 

practicable impact 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 would 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 proposed 

action area. SIO submitted a marine 

mammal monitoring plan as part of the 

IHA application. It can be found in 

Section 13 of the IHA application. The 

plan may be modified or supplemented 

based on comments or new information 

received from the public during the 

public comment period. 

Monitoring measures prescribed by 

NMFS should accomplish one or more 

of the following general goals: 

(1) An increase in the probability of 

detecting marine mammals, both within 

the mitigation zone (thus allowing for 

more effective implementation of the 

mitigation) and in general to generate 

more data to contribute to the analyses 

mentioned below; 

(2) An increase in our understanding 

of how many marine mammals are 

likely to be exposed to levels of sound 

(airguns) that we associate with specific 

adverse effects, such as behavioral 

harassment, TTS, or PTS; 

(3) An increase in our understanding 

of how marine mammals respond to 

stimuli expected to result in take and 

how anticipated adverse effects on 

individuals (in different ways and to 

varying degrees) may impact the 

population, species, or stock 

(specifically through effects on annual 

rates of recruitment or survival) through 

any of the following methods: 

• Behavioral observations in the 

presence of stimuli compared to 

observations in the absence of stimuli 

(need to be able to accurately predict 

received level, distance from source, 

and other pertinent information); 

• Physiological measurements in the 

presence of stimuli compared to 

observations in the absence of stimuli 

(need to be able to accurately predict 

received level, distance from source, 

and other pertinent information); and 

• Distribution and/or abundance 

comparisons in times or areas with 

concentrated stimuli versus times or 

areas without stimuli; 

(4) An increased knowledge of the 

affected species; and 

(5) An increase in our understanding 

of the effectiveness of certain mitigation 

and monitoring measures. 

Proposed Monitoring 

SIO 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. SIO’s proposed 

‘‘Monitoring Plan’’ is described below 

this section. 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. SIO is prepared to 

discuss coordination of their monitoring 

program with any related work that 

might be done by other groups insofar 

as this is practical and desirable. 

Vessel-Based Visual Monitoring 

PSOs would be based aboard the 

seismic source vessel and would watch 

for marine mammals near the vessel 

during daytime airgun operations and 

during any ramp-ups of the airguns at 

night. PSOs would also watch for 

marine mammals near the seismic 

vessel for at least 30 minutes prior to the 

start of airgun operations and after an 

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

approximately 15 minutes for this 

proposed low-energy seismic survey). 

When feasible, PSOs would conduct 

observations during daytime periods 

when the seismic system is not 

operating (such as during transits) for 

comparison of sighting rates and 

behavior with and without airgun 

operations and between acquisition 

periods. Based on PSO observations, the 

airguns would be shut-down when 

marine mammals are observed within or 

about to enter a designated exclusion 

zone. 

During airgun operations in the 

Southwest Pacific Ocean, East of New 

Zealand, at least three PSOs would be 

based aboard the Revelle. At least one 

PSO would stand watch at all times 

while the Revelle is operating airguns 

during the proposed low-energy seismic 

survey; this procedure would also be 

followed when the vessel is in transit. 

SIO would appoint the PSOs with 

NMFS’s concurrence. The lead PSO 

would be experienced with marine 

mammal species in the Pacific Ocean 

and/or off the east coast of New 

Zealand, the second and third PSOs 

would receive additional specialized 

training from the lead PSO to ensure 

that they can identify marine mammal 

species commonly found in the 

Southwest Pacific Ocean. Observations 

would take place during ongoing 

daytime operations and ramp-ups of the 

airguns. During the majority of seismic 

operations, at least one PSO would be 

on duty from observation platforms (i.e., 

the best available vantage point on the 

source vessel) to monitor marine 

mammals near the seismic vessel. 

PSO(s) would be on duty in shifts no 

longer than 4 hours in duration. Other 

crew would also be instructed to assist 

in detecting marine mammals and 

implementing mitigation requirements 

(if practical). Before the start of the lowenergy seismic survey, the crew would 

be given additional instruction on how 

to do so. 

The Revelle is a suitable platform for 

marine mammal observations and 

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would serve as the platform from which 

PSOs would watch for marine mammals 

before and during airgun operations. 

The Revelle has been used for marine 

mammal observations during the 

routine California Cooperative Oceanic 

Fisheries Investigations (CalCOFI). Two 

locations are likely as observation 

stations onboard the Revelle. Observing 

stations are located at the 02 level, with 

PSO eye level at approximately 10.4 m 

(34 ft) above the waterline and the PSO 

would have a good view around the 

entire vessel. At a forward-centered 

position on the 02 deck, the view is 

approximately 240° around the vessel; 

and one atop the aft hangar, with an aftcentered view includes the 100 m radius 

around the GI airguns. The PSO eye 

level on the bridge is approximately 15 

m (49.2 ft) above sea level. PSOs would 

work on the enclosed bridge and 

adjoining aft steering station during any 

inclement weather. 

Standard equipment for PSOs would 

be reticle binoculars and optical range 

finders. Night-vision equipment would 

be available at night and low-light 

conditions during the cruise. The PSOs 

would be in communication with ship’s 

officers on the bridge and scientists in 

the vessel’s operations laboratory, so 

they can advise promptly of the need for 

avoidance maneuvers or seismic source 

shut-down. During daylight, the PSO(s) 

would scan the area around the vessel 

systematically with reticle binoculars 

(e.g., 7 x 50 Fujinon FMTRC–SX), Bigeye binoculars (e.g., 25 x 150 Fujinon 

MT), optical range-finders (to assist with 

distance estimation), and the naked eye. 

These binoculars would have a built-in 

daylight compass. Estimating distances 

is done primarily with the reticles in the 

binoculars. The optical range-finders are 

useful in training PSOs to estimate 

distances visually, but are generally not 

useful in measuring distances to 

animals directly. At night, night-vision 

equipment would be available. The 

PSO(s) would be in direct (radio) 

wireless communication with ship’s 

officers on the bridge and scientists in 

the vessel’s operations laboratory during 

seismic operations, so they can advise 

the vessel operator, science support 

personnel, and the science party 

promptly of the need for avoidance 

maneuvers or a shut-down of the 

seismic source. 

When a marine mammal is detected 

within or about to enter the designated 

exclusion zone, the airguns would 

immediately be shut-down, unless the 

vessel’s speed and/or course can be 

changed to avoid having the animal 

enter the exclusion zone. The PSO(s) 

would continue to maintain watch to 

determine when the animal is outside 

the exclusion zone by visual 

confirmation. Airgun operations would 

not resume until the animal is 

confirmed to have left the exclusion 

zone, or is not observed after 15 minutes 

for species with shorter dive durations 

(small odontocetes and pinnipeds) or 30 

minutes for species with longer dive 

durations (mysticetes and large 

odontocetes, including sperm, dwarf 

and pygmy sperm, killer, and beaked 

whales). 

PSO Data and Documentation 

PSOs would 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 would be used to estimate numbers 

of animals potentially ‘‘taken’’ by 

harassment. They would also provide 

information needed to order a shutdown of the airguns when a marine 

mammal is within or near the exclusion 

zone. Observations would also be made 

during daylight periods when the 

Revelle is underway without seismic 

airgun 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 

would 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 

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

avoidance, approach, paralleling, etc.), 

and behavioral pace. 

2. Time, location, heading, speed, 

activity of the vessel (including number 

of airguns operating and whether in 

state of ramp-up or shut-down), sea 

state, wind force, visibility, cloud cover, 

and sun glare. 

The data listed under (2) would 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 ramp-ups or shutdowns, would be recorded in a 

standardized format. Data would be 

entered into an electronic database. The 

data accuracy would be verified by 

computerized data validity checks as 

the data are entered and by subsequent 

manual checking of the database by the 

PSOs at sea. These procedures would 

allow initial summaries of data to be 

prepared during and shortly after the 

field program, and would facilitate 

transfer of the data to statistical, 

graphical, and other programs for 

further processing and archiving. 

Results from the vessel-based 

observations would 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 airgun 

operations. 

5. Data on the behavior and 

movement patterns of marine mammals 

seen at times with and without airgun 

operations. 

Proposed Reporting 

SIO would submit a comprehensive 

report to NMFS and NSF within 90 days 

after the end of the cruise. The report 

would describe the operations that were 

conducted and sightings of marine 

mammals near the operations. The 

report submitted to NMFS and NSF 

would provide full documentation of 

methods, results, and interpretation 

pertaining to all monitoring. The 90-day 

report would summarize the dates and 

locations of airgun operations and all 

marine mammal sightings (i.e., dates, 

times, locations, activities, and 

associated seismic survey activities). 

The report would include, at a 

minimum: 

• Summaries of monitoring effort— 

total hours, total distances, and 

distribution of marine mammals 

through the study period accounting for 

Beaufort sea state and other factors 

affecting visibility and detectability of 

marine mammals; 

• Analyses of the effects of various 

factors influencing detectability of 

marine mammals including Beaufort sea 

state, number of PSOs, and fog/glare; 

• Species composition, occurrence, 

and distribution of marine mammals 

sightings including date, water depth, 

numbers, age/size/gender, and group 

sizes, and analyses of the effects of 

airgun operations; 

• Sighting rates of marine mammals 

during periods with and without airgun 

operations (and other variables that 

could affect detectability); 

• Initial sighting distances versus 

airgun operations state; 

• Closest point of approach versus 

airgun operations state; 

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• Observed behaviors and types of 

movements versus airgun operations 

activity state; 

• Numbers of sightings/individuals 

seen versus airgun operations state; and 

• Distribution around the source 

vessel versus airgun operations state. 

The report would also include 

estimates of the number and nature of 

exposures that could result in ‘‘takes’’ of 

marine mammals by harassment or in 

other ways. NMFS would review the 

draft report and provide any comments 

it may have, and SIO would incorporate 

NMFS’s comments and prepare a final 

report. After the report is considered 

final, it would be publicly available on 

the NMFS Web site at: http://

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

incidental/. 

Reporting Prohibited Take—In the 

unanticipated event that the specified 

activity clearly causes the take of a 

marine mammal in a manner prohibited 

by this IHA, such as an injury (Level A 

harassment), serious injury or mortality 

(e.g., ship-strike, gear interaction, and/or 

entanglement), SIO would 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 

Howard.Goldstein@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 shall not resume until 

NMFS is able to review the 

circumstances of the prohibited take. 

NMFS shall work with SIO to determine 

what is necessary to minimize the 

likelihood of further prohibited take and 

ensure MMPA compliance. SIO may not 

resume their activities until notified by 

NMFS via letter or email, or telephone. 

Reporting an Injured or Dead Marine 

Mammal With an Unknown Cause of 

Death—In the event that SIO discover 

an injured or dead marine mammal, and 

the lead PSO 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), 

SIO shall 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 

Howard.Goldstein@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 shall work with SIO to 

determine whether modifications in the 

activities are appropriate. 

Reporting an Injured or Dead Marine 

Mammal Not Related to the Activities— 

In the event that SIO discovers an 

injured or dead marine mammal, and 

the lead PSO 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 or advanced 

decomposition, or scavenger damage), 

SIO shall 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 

Howard.Goldstein@noaa.gov, within 24 

hours of discovery. SIO shall 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]. 

TABLE 4—NMFS’S CURRENT UNDERWATER ACOUSTIC EXPOSURE CRITERIA

Criterion Criterion 

definition Threshold 

Impulsive (non-explosive) sound 

Level A 

harassment 

(injury).

Permanent 

threshold 

shift (PTS) 

(Any level 

above that 

which is 

known to 

cause TTS).

180 dB re 1 

μPa-m (root 

means 

square [rms]) 

(cetaceans) 

190 dB re 1 

μPa-m (rms) 

(pinnipeds) 

Level B 

harassment.

Behavioral disruption (for 

impulsive 

noise).

160 dB re 1 

μPa-m (rms) 

Level B 

harassment.

Behavioral disruption (for 

continuous 

noise).

120 dB re 1 

μPa-m (rms) 

Level B harassment is anticipated and 

proposed to be authorized as a result of 

the proposed low-energy seismic survey 

in the Southwest Pacific Ocean, East of 

New Zealand. Acoustic stimuli (i.e., 

increased underwater sound) generated 

during the operation of the seismic 

airgun array are expected to result in the 

behavioral disturbance of some marine 

mammals. NMFS’s current underwater 

exposure criteria for impulsive sound 

are detailed in Table 4 (above). There is 

no evidence that the planned activities 

for which SIO seek the IHA could result 

in injury, serious injury, or mortality. 

The required mitigation and monitoring 

measures would minimize any potential 

risk for injury, serious injury, or 

mortality. 

The following sections describe SIO’s 

methods to estimate take by incidental 

harassment and present the applicant’s 

estimates of the numbers of marine 

mammals that could be affected. The 

estimates are based on a consideration 

of the number of marine mammals that 

could be harassed during the 

approximately 135 hours and 1,250 km 

of seismic airgun operations with the 

two GI airgun array to be used. 

There are no known systematic 

aircraft- or ship-based surveys 

conducted for marine mammals stock 

assessments and very limited 

population information available for 

marine mammals in offshore waters of 

the Southwest Pacific Ocean off the east 

coast of New Zealand. For most 

cetacean species, SIO and NMFS used 

densities from extensive NMFS 

Southwest Fisheries Science Center 

(SWFSC) cruises (Ferguson and Barlow, 

2001, 2003; Barlow, 2003, 2010; Forney, 

2007) in one province of Longhurst’s 

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Federal Register / Vol. 80, No. 54 / Friday, March 20, 2015 / Notices 15089 

(2006) pelagic biogeography, the 

California Current Province (CALC). 

That province is similar to the South 

Subtropical Convergence Province 

(SSTC) in which the proposed lowenergy seismic survey is located, in that 

productivity is high and large pelagic 

fish such as tuna occur. Specifically, 

SIO and NMFS used the 1986 to 1996 

data from blocks 35, 36, 47, 48, 59, and 

60 of Ferguson and Barlow (2001, 2003), 

the 2001 data from Barlow (2003) for the 

Oregon, Washington, and California 

strata, and the 2005 and 2008 data from 

Forney (2007) and Barlow (2010), 

respectively, for the two strata 

combined. The densities used were 

effort-weighted means for the 10 

locations (blocks or States). The surveys 

off California, Oregon, and Washington 

were conducted up to approximately 

556 km (300.2 nmi) offshore, and most 

of those data were from offshore areas 

that overlap with the above blocks 

selected from Ferguson and Barlow 

(2001, 2003). 

For pinnipeds, SIO and NMFS used 

the densities in Bonnell et al. (1992) of 

northern fur seals (Callorhinus ursinus) 

and northern elephant seals in offshore 

areas of the western U.S. (the only 

species regularly present in offshore 

areas there) to estimate the numbers of 

pinnipeds that might be present off New 

Zealand. 

The marine mammal species that 

would be encountered during the 

proposed low-energy seismic survey 

would be different from those sighted 

during surveys off the western U.S. and 

in the Eastern Tropical Pacific Ocean. 

However, the overall abundances of 

species groups with generally similar 

habitat requirements are expected to be 

roughly similar. Thus, SIO and NMFS 

used the data described above to 

estimate the group densities of beaked 

whales, delphinids, small whales, and 

mysticetes in the proposed study area. 

SIO and NMFS then estimated the 

relative abundance of individual 

southern species within the species 

groups using various surveys and other 

information from areas near the study 

area, and general information on 

species’ distributions such as latitudinal 

ranges and group sizes. Group densities 

from northern species were multiplied 

by their estimated relative abundance 

off New Zealand divided by the relative 

abundance for all species in the species 

group to derive estimates for the 

southern species (see Table 3 of the IHA 

application). 

Densities for several cetacean species 

are available for the Southern Ocean 

(Butterworth et al., 1994), as follows: (1) 

For humpback, sei, fin, blue, sperm, 

killer, and pilot whales in Antarctic 

Management areas I to VI south of 60° 

South, based on the 1978/1979 to 1984 

and 1985/1986 to 1990/1991 IWC/IDCR 

circumpolar sighting survey cruises, and 

(2) for humpback, sei, fin, blue, and 

sperm whales extrapolated to latitudes 

30 to 40° South, 40 to 50° South, 50 to 

60° South based on Japanese scouting 

vessel data from 1965/1966 to 

1977/1978 and 1978/1979 to 1987/1988. 

SIO and NMFS calculated densities 

based on abundance and surface areas 

given in Butterworth et al. (1994) and 

used the weighted or mean density for 

the Regions V and/or VI (whichever is 

available) due to locations that represent 

foraging areas or distributions for 

animals that are likely to move past 

New Zealand during northerly 

migrations or breed in New Zealand 

waters. 

The densities used for purposes of 

estimating potential take do not take 

into account the patchy distributions of 

marine mammals in an ecosystem, at 

least on the moderate to fine scales over 

which they are known to occur. Instead, 

animals are considered evenly 

distributed throughout the assessed 

study area and seasonal movement 

patterns are not taken into account, as 

none are available. Although there is 

some uncertainty about the 

representativeness of the data and the 

assumptions used in the calculations 

below, the approach used here is 

believed to be the best available 

approach, using the best available 

science. 

TABLE 5—ESTIMATED DENSITIES AND POSSIBLE NUMBER OF MARINE MAMMAL SPECIES THAT MIGHT BE EXPOSED TO

GREATER THAN OR EQUAL TO 160 dB (AIRGUN OPERATIONS) DURING SIO’S PROPOSED LOW-ENERGY SEISMIC SURVEY (APPROXIMATELY 1,250 km OF TRACKLINES/APPROXIMATELY 1,154 km 2 ENSONIFIED AREA FOR AIRGUN OPERATIONS) IN THE SOUTHWEST PACIFIC OCEAN, EAST OF NEW ZEALAND, MAY TO JUNE 2015 

Species 

Density U.S. 

West Coast/ 

Southern 

Ocean/estimate used 

(number of 

animals/1,000 

km2) 1

Calculated 

take from seismic airgun operations (i.e., 

estimated 

number of individuals exposed to 

sound levels 

≥160 dB re 1 

μPa) 2

Proposed take 

authorization 3 Abundance 4

Approximate percentage of population estimate 

(proposed take) 5

Population 

trend 6

Mysticetes 

Southern right 

whale.

0.98/NA/0.98 1.13 2 8,000 to 15,000—Worldwide. 

12,000—Southern Hemisphere. 

2,700—Sub-Antarctic New Zealand.

0.03—Worldwide. 0.02— 

Southern 

Hemisphere. 

0.07—SubAntarctic New 

Zealand.

Increasing at 7 

to 8% per 

year. 

Pygmy right 

whale.

0.39/NA/0.39 0.45 2 NA ................................................. NA ..................... NA. 

Humpback whale 0.98/0.25/0.25 0.29 2 35,000 to 42,000—Southern 

Hemisphere.

<0.01—Southern 

Hemisphere.

Increasing. 

Antarctic minke 

whale.

0.59/NA/0.59 0.68 2 720,000 to 750,000—Southern 

Hemisphere.

<0.01—Southern 

Hemisphere.

Stable. 

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15090 Federal Register / Vol. 80, No. 54 / Friday, March 20, 2015 / Notices 

TABLE 5—ESTIMATED DENSITIES AND POSSIBLE NUMBER OF MARINE MAMMAL SPECIES THAT MIGHT BE EXPOSED TO

GREATER THAN OR EQUAL TO 160 dB (AIRGUN OPERATIONS) DURING SIO’S PROPOSED LOW-ENERGY SEISMIC SURVEY (APPROXIMATELY 1,250 km OF TRACKLINES/APPROXIMATELY 1,154 km 2 ENSONIFIED AREA FOR AIRGUN OPERATIONS) IN THE SOUTHWEST PACIFIC OCEAN, EAST OF NEW ZEALAND, MAY TO JUNE 2015—Continued 

Species 

Density U.S. 

West Coast/ 

Southern 

Ocean/estimate used 

(number of 

animals/1,000 

km2) 1

Calculated 

take from seismic airgun operations (i.e., 

estimated 

number of individuals exposed to 

sound levels 

≥160 dB re 1 

μPa) 2

Proposed take 

authorization 3 Abundance 4

Approximate percentage of population estimate 

(proposed take) 5

Population 

trend 6

Minke whale (including dwarf 

minke whale 

sub-species).

0.59/NA/0.59 0.68 2 720,000 to 750,000—Southern 

Hemisphere.

<0.01—Southern 

Hemisphere.

NA. 

Bryde’s whale .... 0.20/NA/0.20 0.23 2 At least 30,000 to 40,000—Worldwide. 21,000—Northwestern 

Pacific Ocean 48,109.

<0.01—Worldwide. <0.01— 

Northwestern 

Pacific Ocean 

<0.01.

NA. 

Sei whale ........... 0.59/0.08/0.08 0.09 2 80,000—Worldwide. 10,000— 

South of Antarctic Convergence.

<0.01—Worldwide. 0.02— 

South of Antarctic Convergence.

NA. 

Fin whale ........... 0.59/0.13/0.13 0.15 2 140,000—Worldwide. 15,000— 

South of Antarctic Convergence.

<0.01—Worldwide. 0.01— 

South of Antarctic Convergence.

NA. 

Blue whale ......... 0.59/0.05/0.05 0.06 2 8,000 to 9,000—Worldwide. 

2,300—True Southern Hemisphere. 1,500—Pygmy.

0.03—Worldwide. 0.09— 

True Southern 

Hemisphere. 

0.13—Pygmy.

NA. 

Odontocetes 

Sperm whale ..... 1.62/1.16/1.16 1.34 10 360,000—Worldwide. 30,000— 

South of Antarctic Convergence.

<0.01—Worldwide. 0.03— 

South of Antarctic Convergence.

NA. 

Pygmy sperm 

whale.

0.97/NA/0.97 1.12 5 NA ................................................. NA ..................... NA. 

Cuvier’s beaked 

whale.

0.69/NA/0.69 0.80 2 600,000 ......................................... <0.01 ................. NA 

Shepherd’s 

beaked whale.

0.46/NA/0.46 0.53 3 600,000 ......................................... <0.01 ................. NA. 

Southern 

bottlenose 

whale.

0.46/NA/0.46 0.53 2 50,000—South of Antarctic Convergence 600,000.<0.01—South of 

Antarctic Convergence 

<0.01.

NA. 

Andrew’s beaked 

whale.

0.46/NA/0.46 0.53 2 600,000 ......................................... <0.01 ................. NA. 

Blainville’s 

beaked whale.

0.23/NA/0.23 0.27 2 600,000 ......................................... <0.01 ................. NA. 

Gray’s beaked 

whale.

0.92/NA/0.92 1.06 2 600,000 ......................................... <0.01 ................. NA. 

Hector’s beaked 

whale.

0.46/NA/0.46 0.53 2 600,000 ......................................... <0.01 ................. NA. 

Spade-toothed 

beaked whale.

0.23/NA/0.23 0.27 2 600,000 ......................................... <0.01 ................. NA. 

Strap-toothed 

beaked whale.

0.69/NA/0.69 0.80 3 600,000 ......................................... <0.01 ................. NA. 

Killer whale ........ 0.45/5.70/5.70 6.58 12 80,000—South of Antarctic Convergence.0.02—South of 

Antarctic Convergence.

NA. 

False killer whale 0.27/NA/0.27 0.31 10 NA ................................................. NA ..................... NA. 

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TABLE 5—ESTIMATED DENSITIES AND POSSIBLE NUMBER OF MARINE MAMMAL SPECIES THAT MIGHT BE EXPOSED TO

GREATER THAN OR EQUAL TO 160 dB (AIRGUN OPERATIONS) DURING SIO’S PROPOSED LOW-ENERGY SEISMIC SURVEY (APPROXIMATELY 1,250 km OF TRACKLINES/APPROXIMATELY 1,154 km 2 ENSONIFIED AREA FOR AIRGUN OPERATIONS) IN THE SOUTHWEST PACIFIC OCEAN, EAST OF NEW ZEALAND, MAY TO JUNE 2015—Continued 

Species 

Density U.S. 

West Coast/ 

Southern 

Ocean/estimate used 

(number of 

animals/1,000 

km2) 1

Calculated 

take from seismic airgun operations (i.e., 

estimated 

number of individuals exposed to 

sound levels 

≥160 dB re 1 

μPa) 2

Proposed take 

authorization 3 Abundance 4

Approximate percentage of population estimate 

(proposed take) 5

Population 

trend 6

Long-finned pilot 

whale.

0.27/6.41/6.41 7.40 20 200,000—South of Antarctic Convergence.0.01—South of 

Antarctic Convergence.

NA. 

Short-finned pilot 

whale.

0.45/NA/0.45 0.52 20 At least 600,000—Worldwide ....... <0.01—Worldwide.NA. 

Bottlenose dolphin.81.55/NA/ 

81.55 

94.11 95 At least 614,000—Worldwide ....... 0.02—Worldwide NA. 

Dusky dolphin .... 81.55/NA/ 

81.55 

94.11 95 12,000 to 20,000—New Zealand 0.79—New Zealand.NA. 

Hector’s dolphin 32.62/NA/ 

32.62 

37.64 38 7,400 ............................................. 0.51 ................... Declining. 

Hourglass dolphin.48.93/NA/ 

48.93 

56.47 57 144,000 to 150,000—South of 

Antarctic Convergence.

0.04—South of 

Antarctic Convergence.

NA. 

Short-beaked 

common dolphin.

163.10/NA/ 

163.10 

188.22 189 At least 3,500,000—Worldwide .... <0.01—Worldwide.NA. 

Southern right 

whale dolphin.

48.93/NA/ 

48.93 

56.46 57 NA ................................................. NA ..................... NA. 

Pinnipeds 

Southern elephant seal.5.11/NA/5.11 5.90 6 640,000 to 650,000—Worldwide. 

470,000—South Georgia Island 

607,000.

<0.01—Worldwide or South 

Georgia Island.

Increasing, decreasing, or 

stable depending on breeding population. 

New Zealand fur 

seal.

12.79/NA/ 

12.79 

14.76 15 135,000—Worldwide. 50,000 to 

100,000—New Zealand.

0.01—Worldwide. 0.03— 

New Zealand.

Increasing. 

NA = Not available or not assessed. 

1 Densities based on sightings from NMFS SWFSC, IWC, and Bonnell et al. (2012) data. 2 Calculated take is estimated density multiplied by the area ensonified to 160 dB (rms) around the proposed seismic tracklines, increased by 

25% for contingency. 3Adjusted to account for average group size. 

4See population estimates for marine mammal species in Table 3 (above). 

5Total proposed authorized takes expressed as percentages of the species or regional populations. 

6 Jefferson et al. (2008). 

Numbers of marine mammals that 

might be present and potentially 

disturbed are estimated based on the 

available data about marine mammal 

distribution and densities in the U.S. 

west coast and Southern Ocean as a 

proxy for the proposed study area off 

the east coast of New Zealand. SIO 

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 

(rms) for seismic airgun operations 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 in the area (in the 

absence of the low-energy seismic 

survey). The number of possible 

exposures can be estimated by 

considering the total marine area that 

would be within the 160 dB radius (the 

diameter is 400 m multiplied by 2 for 

deep water depths, the diameter is 600 

m multiplied by 2 for intermediate 

water depths) around the operating 

airguns, including areas of overlap. The 

spacing of tracklines is 500 m (1,640.4 

ft) in the smaller grids and 1,250 m 

(4,101.1 ft) in the larger grids. Overlap 

was measured using GIS and was 

minimal (area with overlap is equal to 

1.13 multiplied by the area without 

overlap). The take estimates were 

calculated without overlap. The 160 dB 

radii are based on acoustic modeling 

data for the airguns that may be used 

during the proposed action (see SIO’s 

IHA application). During the proposed 

low-energy seismic survey, the transect 

lines are widely spaced relative to the 

160 dB distance. As summarized in 

Table 2 (see Table 1 and Figure 2 of the 

IHA application), the modeling results 

for the proposed low-energy seismic 

airgun array indicate the received levels 

are dependent on water depth. Since the 

majority of the proposed airgun 

operations would be conducted in 

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waters 100 to 1,000 m deep or greater 

than 1,000 m deep, the buffer zone of 

600 m or 400 m, respectively, for the 

two 45 in3 GI airguns was used. 

The number of different individuals 

potentially exposed to received levels 

greater than or equal to 160 dB re 1 mPa 

(rms) from seismic airgun operations 

was calculated by multiplying: 

(1) The expected species density (in 

number/km2), times. 

(2) The anticipated area to be 

ensonified to that level during airgun 

operations (excluding overlap). 

The area expected to be ensonified 

was determined by entering the planned 

tracklines into MapInfo GIS using the 

GIS to identify the relevant areas by 

‘‘drawing’’ the applicable 160 dB (rms) 

isopleth around each trackline, and then 

calculating the total area within the 

isopleth. Applying the approach 

described above, approximately 1,153.6 

km2 (including the 25% contingency 

[approximately 923 km2 without 

contingency]) would be ensonified 

within the 160 dB isopleth for seismic 

airgun operations on one or more 

occasions during the proposed lowenergy seismic survey. The total 

ensonified area (1,154 km2 [336.5 nmi2]) 

was calculated by adding 847 km2

(246.9 nmi2) in deep water, 76 km2 (22.2 

nmi2), and 230.8 km2 (67.3 nmi2) for the 

25% contingency. The take calculations 

within the study sites do not explicitly 

add animals to account for the fact that 

new animals (i.e., turnover) not 

accounted for in the initial density 

snapshot could also approach and enter 

the area ensonified above 160 dB for 

seismic airgun operations. However, 

studies suggest that many marine 

mammals would avoid exposing 

themselves to sounds at this level, 

which suggests that there would not 

necessarily be a large number of new 

animals entering the area once the 

seismic survey started. Because this 

approach for calculating take estimates 

does not account for turnover in the 

marine mammal populations in the area 

during the course of the proposed lowenergy seismic survey, the actual 

number of individuals exposed may be 

underestimated. However, any 

underestimation is likely offset by the 

conservative (i.e., probably 

overestimated) line-kilometer distances 

(including the 25% contingency) used 

to calculate the survey area, and the fact 

the approach assumes that no cetaceans 

or pinnipeds would move away or 

toward the tracklines as the Revelle 

approaches in response to increasing 

sound levels before the levels reach 160 

dB for seismic airgun operations, which 

is likely to occur and which would 

decrease the density of marine 

mammals in the survey area. Another 

way of interpreting the estimates in 

Table 6 is that they represent the 

number of individuals that would be 

expected (in absence of a seismic 

program) to occur in the waters that 

would be exposed to greater than or 

equal to 160 dB (rms) for seismic airgun 

operations. 

SIO’s estimates of exposures to 

various sound levels assume that the 

proposed low-energy seismic survey 

would be carried out in full; however, 

the ensonified areas calculated using the 

planned number of line-kilometers has 

been increased by 25% to accommodate 

lines that may need to be repeated, 

equipment testing, etc. As is typical 

during offshore seismic surveys, 

inclement weather and equipment 

malfunctions would be likely to cause 

delays and may limit the number of 

useful line-kilometers of airgun 

operations that can be undertaken. The 

estimates of the numbers of marine 

mammals potentially exposed to 160 dB 

(rms) received levels are precautionary 

and probably overestimate the actual 

numbers of marine mammals that could 

be involved. These estimates assume 

that there would be no weather, 

equipment, or mitigation delays that 

limit the airgun operations, which is 

highly unlikely. 

Table 5 shows the estimates of the 

number of different individual marine 

mammals anticipated to be exposed to 

greater than or equal to 160 dB re 1 mPa 

(rms) for seismic airgun operations 

during the low-energy seismic survey if 

no animals moved away from the survey 

vessel. The total proposed take 

authorization is given in the column 

that is fourth from the left of Table 5. 

Encouraging and Coordinating 

Research 

SIO and NSF would coordinate the 

planned marine mammal monitoring 

program associated with the proposed 

low-energy seismic survey with other 

parties that express interest in this 

activity and area. SIO and NSF would 

coordinate with applicable U.S. 

agencies (e.g., NMFS) and the 

government of New Zealand, and would 

comply with their requirements. The 

proposed low-energy seismic survey 

falls under Level 3 of the ‘‘Code of 

Conduct for minimizing acoustic 

disturbance to marine mammals from 

seismic survey operations’’ issued by 

New Zealand. Level 3 seismic surveys 

are exempt from the provisions of the 

Code of Conduct. 

Impact on Availability of Affected 

Species or Stock for Taking for 

Subsistence Uses 

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

also requires NMFS to determine that 

the authorization would not have an 

unmitigable adverse impact on the 

availability of marine mammal species 

or stocks for subsistence use. There are 

no relevant subsistence uses of marine 

mammals implicated by this action (in 

the Southwest Pacific Ocean, East of 

New Zealand study area). Therefore, 

NMFS has determined that the total 

taking of affected species or stocks 

would not have an unmitigable adverse 

impact on the availability of such 

species or stocks for taking for 

subsistence purposes. 

Analysis and Preliminary 

Determinations 

Negligible Impact 

Negligible impact is ‘‘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’’ 

(50 CFR 216.103). A negligible impact 

finding is based on the lack of likely 

adverse effects on annual rates of 

recruitment or survival (i.e., populationlevel effects). An estimate of the number 

of Level B harassment takes, alone, is 

not enough information on which to 

base an impact determination. In 

addition to considering estimates of the 

number of marine mammals that might 

be ‘‘taken’’ through behavioral 

harassment, NMFS must consider other 

factors, such as the likely nature of any 

responses (their intensity, duration, etc.) 

and the context of any responses 

(critical reproductive time or location, 

migration, etc.), as well as the number 

and nature of estimated Level A 

harassment takes, the number of 

estimated mortalities, effects on habitat, 

and the status of the species. 

In making a negligible impact 

determination, NMFS evaluated factors 

such as: 

(1) The number of anticipated serious 

injuries and or mortalities; 

(2) The number and nature of 

anticipated injuries; 

(3) The number, nature, intensity, and 

duration of takes by Level B harassment 

(all of which are relatively limited in 

this case); 

(4) The context in which the takes 

occur (e.g., impacts to areas of 

significance, impacts to local 

populations, and cumulative impacts 

when taking into account successive/

contemporaneous actions when added 

to baseline data); 

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(5) The status of stock or species of 

marine mammals (i.e., depleted, not 

depleted, decreasing, increasing, stable, 

impact relative to the size of the 

population); 

(6) Impacts on habitat affecting rates 

of recruitment/survival; and 

(7) The effectiveness of monitoring 

and mitigation measures. 

NMFS has preliminarily determined 

that the specified activities associated 

with the marine seismic survey are not 

likely to cause PTS, or other (nonauditory) injury, serious injury, or 

death, based on the analysis above and 

the following factors: 

(1) The likelihood that, given 

sufficient notice through relatively slow 

ship speed, marine mammals are 

expected to move away from a noise 

source that is annoying prior to its 

becoming potentially injurious; 

(2) The availability of alternate areas 

of similar habitat value for marine 

mammals to temporarily vacate the 

survey area during the operation of the 

airgun(s) to avoid acoustic harassment; 

(3) The potential for temporary or 

permanent hearing impairment is 

relatively low and would likely be 

avoided through the implementation of 

the required monitoring and mitigation 

measures (including shut-down 

measures); and 

(4) 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 the SIO’s planned low-energy 

seismic survey, and none are proposed 

to be authorized by NMFS. Table 5 of 

this document outlines the number of 

requested Level B harassment takes that 

are anticipated as a result of these 

activities. Due to the nature, degree, and 

context of Level B (behavioral) 

harassment anticipated and described in 

this notice (see ‘‘Potential Effects on 

Marine Mammals’’ section above), the 

activity is not expected to impact rates 

of annual recruitment or survival for 

any affected species or stock, 

particularly given NMFS’s and the 

applicant’s proposed mitigation, 

monitoring, and reporting measures to 

minimize impacts to marine mammals. 

Additionally, the low-energy seismic 

survey would not adversely impact 

marine mammal habitat. 

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 airgun operations are anticipated 

to occur on consecutive days, the 

estimated duration of the survey would 

not last more than a total of 

approximately 27 operational days. 

Additionally, the low-energy seismic 

survey would be increasing sound levels 

in the marine environment in a 

relatively small area surrounding the 

vessel (compared to the range of the 

animals), which is constantly travelling 

over distances, so individual animals 

likely would only be exposed to and 

harassed by sound for less than a day. 

As mentioned previously, NMFS 

estimates that 32 species of marine 

mammals under its jurisdiction could be 

potentially affected by Level B 

harassment over the course of the IHA. 

The population estimates for the marine 

mammal species that may be taken by 

Level B harassment were provided in 

Table 3 and 5 of this document. As 

shown in those tables, the proposed 

takes represent small proportions of the 

overall populations of these marine 

mammal species where abundance 

estimates are available (i.e., less than 

1%). 

Of the 32 marine mammal species 

under NMFS jurisdiction that may or 

are known to likely occur in the study 

area, six are listed as threatened or 

endangered under the ESA: Southern 

right, humpback, sei, fin, blue, and 

sperm whales. These species are also 

considered depleted under the MMPA. 

None of the other marine mammal 

species that may be taken are listed as 

depleted under the MMPA. Of the ESAlisted species, incidental take has been 

requested to be authorized for six 

species. As mitigation to reduce impacts 

to the affected species or stocks, SIO 

would be required to cease airgun 

operations if any marine mammal enters 

designated exclusion zones. No injury, 

serious injury, or mortality is expected 

to occur for any of these species, and 

due to the nature, degree, and context of 

the Level B harassment anticipated, and 

the activity is not expected to impact 

rates of recruitment or survival for any 

of these species. 

NMFS has preliminarily determined 

that, provided that the aforementioned 

mitigation and monitoring measures are 

implemented, the impact of conducting 

a low-energy marine seismic survey in 

the Southwest Pacific Ocean, May to 

June 2015, may result, at worst, in a 

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

harassment) of certain species of marine 

mammals. 

While behavioral modifications, 

including temporarily vacating the area 

during the operation of the airgun(s), 

may be made by these species to avoid 

the resultant acoustic disturbance, the 

availability of alternate areas for species 

to move to and the short and sporadic 

duration of the research activities, have 

led NMFS to preliminary determine that 

the taking by Level B harassment from 

the specified activity would have a 

negligible impact on the affected species 

in the specified geographic region. 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 annual recruitment or 

survival for any affected species or 

stock, particularly given the NMFS and 

applicant’s proposal to implement 

mitigation and monitoring measures 

would minimize impacts to marine 

mammals. 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 proposed monitoring and 

mitigation measures, NMFS 

preliminarily finds that the total marine 

mammal take from SIO’s proposed lowenergy seismic survey would have a 

negligible impact on the affected marine 

mammal species or stocks. 

Small Numbers 

As mentioned previously, NMFS 

estimates that 32 species of marine 

mammals under its jurisdiction could be 

potentially affected by Level B 

harassment over the course of the IHA. 

The population estimates for the marine 

mammal species that may be taken by 

Level B harassment were provided in 

Tables 3 and 5 of this document. 

The estimated numbers of individual 

cetaceans and pinnipeds that could be 

exposed to seismic sounds with 

received levels greater than or equal to 

160 dB re 1 mPa (rms) during the 

proposed low-energy seismic survey 

(including a 25% contingency) are in 

Table 5 of this document. Of the 

cetaceans, 2 southern right, 2 pygmy 

right, 2 humpback, 2 Antarctic minke, 2 

minke, 2 Bryde’s, 2 sei, 2 fin, 2 blue, 

and 10 sperm whales could be taken by 

Level B harassment during the proposed 

low-energy seismic survey, which 

would represent 0.03, unknown, 0.1, 

less than 0.01, less than 0.01, less than 

0.01, less than 0.01, less than 0.01, 0.03, 

and 0.03% of the affected worldwide or 

regional populations, respectively. In 

addition, 5 pygmy sperm, 2 Cuvier’s 

beaked, 3 Shepherd’s beaked, 2 

southern bottlenose, 2 Andrew’s beaked, 

2 Blainville’s beaked, 2 Gray’s beaked, 

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2 Hector’s beaked, 2 spade-toothed 

beaked, and 3 strap-toothed beaked 

could be taken be Level B harassment 

during the proposed low-energy seismic 

survey, which would represent 

unknown, less than 0.01, less than 0.01, 

less than 0.01, less than 0.01, less than 

0.01, less than 0.01, less than 0.01, less 

than 0.01, and less than 0.01% of the 

affected worldwide or regional 

populations, respectively. Of the 

delphinids, 12 killer whales, 10 false 

killer whales, 20 long-finned pilot 

whales, 20 short-finned pilot whales, 95 

bottlenose dolphins, 95 dusky dolphins, 

38 Hector’s dolphins, 57 hourglass 

dolphins, 189 short-beaked common 

dolphins, and 57 southern right whale 

dolphins could be taken by Level B 

harassment during the proposed lowenergy seismic survey, which would 

represent 0.02, unknown, 0.01, less than 

0.01, 0.02, 0.79, 0.51, 0.04, less than 

0.01, and unknown of the affected 

worldwide or regional populations, 

respectively. Of the pinnipeds, 15 New 

Zealand fur seals and 6 southern 

elephant seals could be taken by Level 

B harassment during the proposed lowenergy seismic survey, which would 

represent 0.01 and less than 0.01 of the 

affected worldwide or regional 

population, respectively. 

No known current worldwide or 

regional population estimates are 

available for 4 species under NMFS’s 

jurisdiction that could potentially be 

affected by Level B harassment over the 

course of the IHA. These species are the 

pygmy right, pygmy sperm, and false 

killer whales and southern right whale 

dolphins. Pygmy right whales have a 

circumglobal distribution and occur 

throughout coastal and oceanic waters 

in the Southern Hemisphere (between 

30 to 55° South) (Jefferson et al., 2008). 

Pygmy sperm whales occur in deep 

waters on the outer continental shelf 

and slope in tropical to temperate 

waters of the Atlantic, Indian, and 

Pacific Oceans. False killer whales 

generally occur in deep offshore tropical 

to temperate waters (between 50° North 

to 50° South) of the Atlantic, Indian, 

and Pacific Oceans (Jefferson et al., 

2008). Southern right whale dolphins 

have a circumpolar distribution and 

generally occur in deep temperate to 

sub-Antarctic waters in the Southern 

Hemisphere (between 30 to 65° South) 

(Jefferson et al., 2008). Based on these 

distributions and preferences of these 

species, NMFS concludes that the 

requested take of these species likely 

represent small numbers relative to the 

affected species’ overall population 

sizes. 

NMFS makes its small numbers 

determination based on the numbers of 

marine mammals that would be taken 

relative to the populations of the 

affected species or stocks. The proposed 

take estimates all represent small 

numbers relative to the affected species 

or stock size (i.e., all are less than 1%), 

with the exception of the four species 

(i.e., pygmy right, pygmy sperm, and 

false killer whales and southern right 

whale dolphins) for which a qualitative 

rationale was provided. 

Endangered Species Act 

Of the species of marine mammals 

that may occur in the proposed survey 

area, six are listed as endangered under 

the ESA: The southern right, humpback, 

sei, fin, blue, and sperm whales. Under 

section 7 of the ESA, NSF, on behalf of 

SIO, has initiated formal consultation 

with the NMFS, Office of Protected 

Resources, Endangered Species Act 

Interagency Cooperation Division, on 

this proposed low-energy seismic 

survey. NMFS’s Office of Protected 

Resources, Permits and Conservation 

Division, has initiated formal 

consultation under section 7 of the ESA 

with NMFS’s 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 

would conclude formal section 7 

consultation prior to making a 

determination on whether or not to 

issue the IHA. If the IHA is issued, in 

addition to the mitigation and 

monitoring requirements included in 

the IHA, NSF and SIO would be 

required to comply with the Terms and 

Conditions of the Incidental Take 

Statement corresponding to NMFS’s 

Biological Opinion issued to both NSF 

and SIO, and NMFS’s Office of 

Protected Resources. 

National Environmental Policy Act 

With SIO’s complete IHA application, 

NSF and SIO provided NMFS a ‘‘Draft 

Environmental Analysis of a LowEnergy Marine Geophysical Survey by 

the R/V Roger Revelle in the Southwest 

Pacific Ocean, East of New Zealand, 

May to June 2015,’’ (Draft 

Environmental Analysis), prepared by 

LGL Limited, Environmental Research 

Associates, on behalf of NSF and SIO. 

The Draft Environmental Analysis 

analyzes the direct, indirect, and 

cumulative environmental impacts of 

the proposed specified activities on 

marine mammals, including those listed 

as threatened or endangered under the 

ESA. NMFS, after independently 

reviewing and evaluating the document 

for sufficiency and compliance with 

Council on Environmental Quality 

(CEQ) NEPA regulations and NOAA 

Administrative Order 216–6 § 5.09(d), 

will conduct a separate NEPA analysis 

and prepare a ‘‘Draft Environmental 

Assessment on the Issuance of an 

Incidental Harassment Authorization to 

the Scripps Institution of Oceanography 

to Take Marine Mammals by 

Harassment Incidental to a Low-Energy 

Marine Geophysical Survey in the 

Southwest Pacific Ocean, East of New 

Zealand, May to June 2015,’’ and decide 

whether to sign a Finding of No 

Significant Impact (FONSI), prior to 

making a determination on the issuance 

of the IHA. 

Proposed Authorization 

As a result of these preliminary 

determinations, NMFS proposes to issue 

an IHA to SIO for conducting the lowenergy seismic survey in the Southwest 

Pacific Ocean, East of New Zealand, 

provided the previously mentioned 

mitigation, monitoring, and reporting 

requirements are incorporated. This 

section contains a draft of the IHA itself. 

The wording contained in this section is 

proposed for inclusion in the IHA (if 

issued). The proposed IHA language is 

provided below: 

The NMFS hereby authorizes the 

Scripps Institution of Oceanography, 

8602 La Jolla Shores Drive, La Jolla, 

California 92037, under section 

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

Protection Act (MMPA) (16 U.S.C. 

1371(a)(5)(D)), to harass small numbers 

of marine mammals incidental to a lowenergy marine geophysical (seismic) 

survey conducted by the R/V Roger 

Revelle (Revelle) in the Southwest 

Pacific Ocean, East of New Zealand, 

May to June 2015: 

1. Effective Dates 

This Authorization is valid from May 

18, 2015 through July 30, 2015. 

2. Specified Activity and Geographic 

Region 

This Authorization is valid only for 

SIO’s activities associated with lowenergy seismic survey, bathymetric 

profile, and heat-flow probe 

measurements conducted aboard the 

Revelle that shall occur in the following 

specified geographic area: 

(a) In selected regions of the 

Southwest Pacific Ocean off the east 

coast of New Zealand. The survey sites 

are located in the Exclusive Economic 

Zone, outside of territorial waters 

(located between approximately 38.5 

and 42.5° South, and between 174 and 

180° East). Water depths in the survey 

area are expected to be approximately 

200 to 3,000 m. No airgun operations 

would occur in shallow (less than 100 

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m) water depths. Airgun operations 

would take approximately 135 hours in 

total and 1,250 km, and the remainder 

of the time would be spent in transit 

and collecting heat-flow measurements 

and sediment core samples. The lowenergy seismic survey would be 

conducted as specified in SIO’s IHA 

application and the associated NSF and 

SIO Environmental Analysis. 

3. This Authorization does not permit 

incidental takes of marine mammals in 

the territorial sea of foreign nations, as 

the MMPA does not apply in those 

waters. The territorial sea extends at the 

most 22.2 kilometers (km) (12 nautical 

miles [nmi]) from the baseline of a 

coastal State. 

4. Species Authorized and Level of 

Takes 

(a) The incidental taking of marine 

mammals, by Level B harassment only, 

is limited to the following species in the 

waters of the Southwest Pacific Ocean, 

East of New Zealand: 

(i) Mysticetes—see Table 5 (above) for 

authorized species and take numbers. 

(ii) Odontocetes—see Table 5 (above) 

for authorized species and take 

numbers. 

(iii) Pinnipeds—see Table 5 (above) 

for authorized species and take 

numbers. 

(iv) If any marine mammal species are 

encountered during seismic activities 

that are not listed in Table 5 (above) for 

authorized taking and are likely to be 

exposed to sound pressure levels (SPLs) 

greater than or equal to 160 dB re 1 mPa 

(rms) for seismic airgun operations, then 

the SIO must alter speed or course or 

shut-down the airguns to prevent take. 

(b) The taking by injury (Level A 

harassment), serious injury, or death of 

any of the species listed in Condition 

4(a) above or the taking of any kind of 

any other species of marine mammal is 

prohibited and may result in the 

modification, suspension, or revocation 

of this Authorization. 

5. The sources authorized for taking 

by Level B harassment are limited to the 

following acoustic sources, absent an 

amendment to this Authorization: 

A two Generator Injector (GI) airgun 

array (each with a discharge volume of 

45 cubic inches [in3]) with a total 

volume of 90 in3 (or smaller). 

6. Prohibited Take 

The taking of any marine mammal in 

a manner prohibited under this 

Authorization must be reported 

immediately to the Office of Protected 

Resources, National Marine Fisheries 

Service (NMFS), at 301–427–8401. 

7. Mitigation and Monitoring 

Requirements 

The SIO is required to implement the 

following mitigation and related 

monitoring requirements when 

conducting the specified activities to 

achieve the least practicable impact on 

affected marine mammal species or 

stocks: 

Protected Species Observers and Visual 

Monitoring 

(a) Utilize at least one NMFSqualified, vessel-based Protected 

Species Observer (PSO) to visually 

watch for and monitor marine mammals 

near the seismic source vessel during 

daylight airgun operations (from 

nautical twilight-dawn to nautical 

twilight-dusk) and before and during 

ramp-ups of airguns day or night. Three 

PSOs shall be based onboard the vessel. 

(i) The Revelle’s vessel crew shall also 

assist in detecting marine mammals, 

when practicable. 

(ii) PSOs shall have access to reticle 

binoculars (7 x 50 Fujinon) equipped 

with a built-in daylight compass and 

range reticles, big-eye binoculars (25 x 

150), optical range finders, and nightvision devices. 

(iii) PSO shifts shall last no longer 

than 4 hours at a time. 

(iv) PSO(s) shall also make 

observations during daylight periods 

when the seismic airguns are not 

operating, when feasible, for 

comparison of animal abundance and 

behavior. 

(v) PSO(s) shall conduct monitoring 

while the airgun array and streamer(s) 

are being deployed or recovered from 

the water. 

(b) PSO(s) shall record the following 

information when a marine mammal is 

sighted: 

(i) 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 

including responses to ramp-up), and 

behavioral pace; and 

(ii) Time, location, heading, speed, 

activity of the vessel (including number 

of airguns operating and whether in 

state of ramp-up or shut-down), 

Beaufort sea state and wind force, 

visibility, and sun glare; and 

(iii) The data listed under Condition 

7(b)(ii) shall 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. 

Buffer and Exclusion Zones 

(c) Establish a 160 dB re 1 m Pa (rms) 

buffer zone, as well as a180 dB re 1 m Pa 

(rms) exclusion zone for cetaceans and 

a 190 dB re 1 m Pa (rms) exclusion zone 

for pinnipeds before the two GI airgun 

array (90 in3 total volume) is in 

operation. See Table 2 (above) for 

distances and buffer and exclusion 

zones. 

Visual Monitoring at the Start of the 

Airgun Operations 

(d) Visually observe the entire extent 

of the exclusion zone (180 dB re 1 m Pa 

[rms] for cetaceans and 190 dB re 1 m Pa 

[rms] for pinnipeds; see Table 2 [above] 

for distances) using two NMFS-qualified 

PSOs, for at least 30 minutes prior to 

starting the airgun array (day or night). 

(i) If the PSO(s) sees a marine 

mammal within the exclusion zone, SIO 

must delay the seismic survey until the 

marine mammal(s) has left the area. If 

the PSO(s) sees a marine mammal that 

surfaces, then dives below the surface, 

the PSO(s) shall continue to observe the 

exclusion zone for 30 minutes, and if 

the PSO sees no marine mammals 

during that time, the PSO should 

assume that the animal has moved 

beyond the exclusion zone. 

(ii) If for any reason the entire radius 

cannot be seen for the entire 30 minutes 

(i.e., rough seas, fog, darkness), or if 

marine mammals are near, approaching, 

or in the exclusion zone, the airguns 

may not be ramped-up. If one airgun is 

already running at a source level of at 

least 180 dB re 1 m Pa (rms), SIO may 

start the second airgun without 

observing the entire exclusion zone for 

30 minutes prior, provided no marine 

mammals are known to be near the 

exclusion zone (in accordance with 

Condition 7[e] below). 

Ramp-Up Procedures 

(e) Implement a ‘‘ramp-up’’ 

procedure, which means starting with a 

single GI airgun and adding a second GI 

airgun after five minutes, when starting 

up at the beginning of seismic 

operations or anytime after the entire 

array has been shut-down for more than 

15 minutes. During ramp-up, the two 

PSOs shall monitor the exclusion zone, 

and if marine mammals are sighted, a 

shut-down shall be implemented as 

though the full array (both GI airguns) 

were operational. Therefore, initiation 

of ramp-up procedures from shut-down 

requires that the two PSOs be able to 

view the full exclusion zone as 

described in Condition 7(d) (above). 

Shut-Down Procedures 

(f) Shut-down the airgun(s) if a marine 

mammal is detected within, approaches, 

or enters the relevant exclusion zone (as 

defined in Table 2, above). A shut-down 

means all operating airguns are shutdown (i.e., turned off). 

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(g) Following a shut-down, the airgun 

activity shall not resume until the 

PSO(s) has visually observed the marine 

mammal(s) exiting the exclusion zone 

and determined it is not likely to return, 

or has not seen the marine mammal 

within the exclusion zone for 15 

minutes, for species with shorter dive 

durations (small odontocetes and 

pinnipeds), or 30 minutes for species 

with longer dive durations (mysticetes 

and large odontocetes, including sperm, 

dwarf and pygmy sperm, killer, and 

beaked whales). 

(h) Following a shut-down and 

subsequent animal departure, airgun 

operations may resume, following the 

ramp-up procedures described in 

Condition 7(e). 

Speed or Course Alteration 

(i) Alter speed or course during 

seismic operations if a marine mammal, 

based on its position and relative 

motion, appears likely to enter the 

relevant exclusion zone. If speed or 

course alteration is not safe or 

practicable, or if after alteration the 

marine mammal still appears likely to 

enter the exclusion zone, further 

mitigation measures, such as a shutdown, shall be taken. 

Survey Operations During Low-Light 

Hours 

(j) Marine seismic surveying may 

continue into low-light hours if such 

segment(s) of the survey is initiated 

when the entire relevant exclusion 

zones are visible and can be effectively 

monitored. 

(k) No initiation of airgun array 

operations is permitted from a shutdown position during low-light hours 

(such as in dense fog or heavy rain) 

when the entire relevant exclusion zone 

cannot be effectively monitored by the 

PSO(s) on duty. 

(l) To the maximum extent 

practicable, schedule seismic operations 

(i.e., shooting airguns) during daylight 

hours, and heat-flow measurements at 

nighttime hours. 

8. Reporting Requirements 

SIO are required to: 

(a) Submit a draft report on all 

activities and monitoring results to the 

Office of Protected Resources, NMFS, 

within 90 days of the completion of the 

Revelle’s Southwest Pacific Ocean, East 

of New Zealand cruise. This report must 

contain and summarize the following 

information: 

(i) Dates, times, locations, heading, 

speed, weather, sea conditions 

(including Beaufort sea state and wind 

force), and associated activities during 

all seismic operations and marine 

mammal sightings; 

(ii) Species, number, location, 

distance from the vessel, and behavior 

of any marine mammals, as well as 

associated seismic activity (e.g., number 

of shut-downs), observed throughout all 

monitoring activities. 

(iii) An estimate of the number (by 

species) of marine mammals that: (A) 

Are known to have been exposed to the 

seismic activity (based on visual 

observation) at received levels greater 

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

(for seismic airgun operations), and/or 

180 dB re 1 mPa (rms) for cetaceans and 

190 dB re 1 mPa (rms) for pinnipeds, 

with a discussion of any specific 

behaviors those individuals exhibited; 

and (B) may have been exposed (based 

on modeled values for the two GI airgun 

array) to the seismic activity at received 

levels greater than or equal to 160 dB re 

1 mPa (rms) (for seismic airgun 

operations), and/or 180 dB re 1 mPa 

(rms) for cetaceans and 190 dB re 1 mPa 

(rms) for pinnipeds, with a discussion of 

the nature of the probable consequences 

of that exposure on the individuals that 

have been exposed. 

(iv) A description of the 

implementation and effectiveness of the: 

(A) Terms and Conditions of the 

Biological Opinion’s Incidental Take 

Statement (ITS) (attached); and (B) 

mitigation measures of the IHA. For the 

Biological Opinion, the report shall 

confirm the implementation of each 

Term and Condition, as well as any 

conservation recommendations, and 

describe their effectiveness, for 

minimizing the adverse effects of the 

action on Endangered Species Act-listed 

marine mammals. 

(b) Submit a final report to the Chief, 

Permits and Conservation Division, 

Office of Protected Resources, NMFS, 

within 30 days after receiving comments 

from NMFS on the draft report. If NMFS 

decides that the draft report needs no 

comments, the draft report shall be 

considered to be the final report. 

8. Reporting Prohibited Take 

(a) (i) In the unanticipated event that 

the specified activity clearly causes the 

take of a marine mammal in a manner 

prohibited by this Authorization, such 

as an injury (Level A harassment), 

serious injury or mortality (e.g., through 

ship-strike, gear interaction, and/or 

entanglement), SIO 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 

Howard.Goldstein@noaa.gov. The report 

must include the following information: 

(ii) Time, date, and location (latitude/ 

longitude) of the incident; the name and 

type of vessel involved; the 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 marine mammal 

observations in the 24 hours preceding 

the incident; species identification or 

description of the animal(s) involved; 

the fate of the animal(s); and 

photographs or video footage of the 

animal (if equipment is available). 

Activities shall not resume until 

NMFS is able to review the 

circumstances of the prohibited take. 

NMFS shall work with SIO to determine 

what is necessary to minimize the 

likelihood of further prohibited take and 

ensure MMPA compliance. SIO may not 

resume their activities until notified by 

NMFS via letter, email, or telephone. 

Reporting an Injured or Dead Marine 

Mammal With an Unknown Cause of 

Death 

(b) In the event that SIO discover an 

injured or dead marine mammal, and 

the lead PSO 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), 

SIO shall 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 

Howard.Goldstein@noaa.gov. The report 

must include the same information 

identified in Condition 8(c)(i) above. 

Activities may continue while NMFS 

reviews the circumstances of the 

incident. NMFS shall work with SIO to 

determine whether modifications in the 

activities are appropriate. 

Reporting an Injured or Dead Marine 

Mammal Not Related to the Activities 

(c) In the event that SIO discovers an 

injured or dead marine mammal, and 

the lead PSO determines that the injury 

or death is not associated with or related 

to the activities authorized in Condition 

2 of this Authorization (e.g., previously 

wounded animal, carcass with moderate 

to advanced decomposition, or 

scavenger damage), SIO shall 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 

Howard.Goldstein@noaa.gov, within 24 

hours of the discovery. SIO shall 

provide photographs or video footage (if 

available) or other documentation of the 

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stranded animal sighting to NMFS. 

Activities may continue while NMFS 

reviews the circumstances of the 

incident. 

9. Endangered Species Act Biological 

Opinion and Incidental Take Statement 

(a) SIO is required to comply with the 

Terms and Conditions of the ITS 

corresponding to NMFS’s Biological 

Opinion issued to both NSF and SIO, 

and NMFS’s Office of Protected 

Resources. 

(b) A copy of this Authorization and 

the ITS must be in the possession of all 

contractors and PSO(s) operating under 

the authority of this Incidental 

Harassment Authorization. 

Request for Public Comments 

NMFS requests comment on our 

analysis, the draft authorization, and 

any other aspect of the notice of the 

proposed IHA for SIO’s low-energy 

seismic survey. Please include with 

your comments any supporting data or 

literature citations to help inform our 

final decision on SIO’s request for an 

MMPA authorization. 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 12, 2015. 

Perry Gayaldo, 

Deputy Director, Office of Protected 

Resources, National Marine Fisheries Service. 

[FR Doc. 2015–06261 Filed 3–19–15; 8:45 am] 

BILLING CODE 3510–22–P 

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