Taking and Importing Marine Mammals; Taking Marine Mammals Incidental to Navy Operations of Surveillance Towed Array Sensor System Low Frequency Active Sonar

address or by telephoning one of the contacts listed here (see FOR

FURTHER INFORMATION CONTACT). A copy of the draft environmental impact

statement (DEIS) for SURTASS LFA sonar may be obtained by contacting

Mr. J.S. Johnson, SURTASS-LFA Sonar Program Manager, 901 North Stewart

Street, Suit 708, Arlington, VA 22203. Comments on the DEIS will be

accepted at this address until October 28, 1999.

FOR FURTHER INFORMATION CONTACT: Kenneth R. Hollingshead (301) 713-

2055, ext. 128.

SUPPLEMENTARY INFORMATION:

Background

Section 101(a)(5)(A) of the Marine Mammal Protection Act (MMPA) (16

U.S.C. 1361 et seq.) directs the Secretary of Commerce (Secretary) to

allow, upon request, the incidental, but not intentional taking of

marine mammals by U.S. citizens who engage in a specified activity

(other than commercial fishing) within a specified geographical region

if certain findings are made and regulations are issued.

Permission may be granted for periods of 5 years or less if the

Secretary finds that the taking will have a negligible impact on the

species or stock(s) of affected marine mammals, will not have an

unmitigable adverse impact on the availability of the species or

stock(s) for subsistence uses, and regulations are prescribed setting

forth the permissible methods of taking and the requirements pertaining

to the monitoring and reporting of such taking.

Summary of Request

On August 12, 1999, NMFS received an application from the U.S. Navy

requesting a small take exemption under section 101(a)(5)(A) of the

MMPA for the taking of marine mammals by harassment incidental to

operation of the SURTASS LFA sonar for a period of time not to exceed 5

years, beginning in FY 2000. SURTASS LFA sonar will operate a maximum

of 4 ship systems in the ten geographic operating regions in which

SURTASS LFA sonar could potentially operate. There would be a maximum

of four SURTASS LFA sonar systems with a nominal maximum of two systems

at sea at any one time.

Description of the Activity

n of the SURTASS LFA sonar for a period of time not to exceed 5

years, beginning in FY 2000. SURTASS LFA sonar will operate a maximum

of 4 ship systems in the ten geographic operating regions in which

SURTASS LFA sonar could potentially operate. There would be a maximum

of four SURTASS LFA sonar systems with a nominal maximum of two systems

at sea at any one time.

Description of the Activity

The SURTASS LFA sonar system is a long-range, low frequency

(between 100 and 500 Hertz) sonar that has both active and passive

components. It does not rely on detection of noise generated by the

target. The active component of the system is a set of low frequency

(LF) acoustic transmitting source elements (called projectors)

suspended from a cable from underneath a ship. The projectors are

devices that produce the active sound or pulse.

The typical SURTASS LFA sonar signal is not a constant tone, but

rather a transmission of various waveforms that vary in frequency and

duration. A complete sequence of sound transmissions is referred to as

a ``ping'' and can last for as short as 6 seconds (sec) to as long as

100 sec. The time between pings is typically from 6 to 15 minutes.

Average duty cycle (ratio of sound ``on'' time to total time) can be

controlled but is less than 20 percent; typical duty cycle is between

10 and 20 percent.

The passive or listening component of the system is SURTASS, which

detects returning echoes from submerged objects, such as submarines,

through the use of hydrophones. The hydrophones are mounted on a

horizontal array that is towed behind the ship. The SURTASS LFA sonar

ship maintains a minimum speed of 5.6 km/hr (3.0 knots).

The Navy anticipates that a nominal, or typical SURTASS LFA sonar

deployment schedule for a single vessel would involve about 270 days/

year at sea (underway). A typical at-sea mission would occur over a 30-

day period, made up of two 9-day exercise segments

unted on a

horizontal array that is towed behind the ship. The SURTASS LFA sonar

ship maintains a minimum speed of 5.6 km/hr (3.0 knots).

The Navy anticipates that a nominal, or typical SURTASS LFA sonar

deployment schedule for a single vessel would involve about 270 days/

year at sea (underway). A typical at-sea mission would occur over a 30-

day period, made up of two 9-day exercise segments. Active sonar

operations could be conducted up to 20 hrs during an exercise day,

although the system would actually be transmitting for only a

maximum of 4 hrs/day (resulting in 432 hrs of active transmission time

per year for each SURTASS LFA sonar system in operation based on a

maximum duty cycle of 20 percent). The remaining 12 days of the at-sea

mission would be spent in transit or repositioning the vessel. In a

nominal year there could be a maximum of 9 missions, six of which would

involve the employment of SURTASS LFA sonar in the active mode and

three of which would employ the SURTASS LFA sonar in the passive mode.

Between missions, an estimated 95 days would be spent in port for

upkeep and repair. With two vessels in the Pacific-Indian Ocean area

and two vessels in the Atlantic Ocean-Mediterranean Sea area, there

could be up to 12 operations in each area per year.

At present, only one SURTASS LFA sonar system is operational. A

second SURTASS LFA sonar system is expected to be operational in FY

2000. The third and fourth systems are tentatively planned for FY 2003

and FY 2004, but their delivery may be postponed until after FY 2005.

With 4 systems, a nominal maximum of two vessels would be at sea at any

one time. As a result, under 5-year regulations NMFS would propose to

authorize marine mammal harassment takings for 2 SURTASS LFA sonar

vessels for FY 2000 through FY 2002, 3 vessels for FY 2003, and 4

vessels for FY 2004.

Affected Marine Mammal Species

d FY 2004, but their delivery may be postponed until after FY 2005.

With 4 systems, a nominal maximum of two vessels would be at sea at any

one time. As a result, under 5-year regulations NMFS would propose to

authorize marine mammal harassment takings for 2 SURTASS LFA sonar

vessels for FY 2000 through FY 2002, 3 vessels for FY 2003, and 4

vessels for FY 2004.

Affected Marine Mammal Species

In their DEIS analysis and small take application, the Navy

excluded from take consideration those marine mammal species that

either do not inhabit the areas wherein SURTASS LFA sonar would operate

or do not possess sensory mechanisms that allow the mammal to perceive

low frequency (LF) sounds. Where data was not available or was

insufficient for one species, comparable data for a related species was

used, if available. Because all species of baleen whales produce LF

sounds, and anatomical evidence strongly suggests that their inner ears

are well adapted for LF hearing, all species are considered sensitive

to LF sound and at risk from exposure to LF sounds. The ten species of

baleen whales that may be affected by SURTASS LFA sonar are: blue

(Balaenoptera musculus), fin (Balaenoptera physalus), minke

(Balaenoptera acutorostrata), Bryde's (Balaenoptera borealis), sei

(Balaenoptera borealis), humpback (Megaptera novaeangliae), northern

right (Eubalaena glacialis), southern right (Eubalaena australis),

pygmy right (Capera marginata), and gray whales (Eschrichtius

robustus)

whales that may be affected by SURTASS LFA sonar are: blue

(Balaenoptera musculus), fin (Balaenoptera physalus), minke

(Balaenoptera acutorostrata), Bryde's (Balaenoptera borealis), sei

(Balaenoptera borealis), humpback (Megaptera novaeangliae), northern

right (Eubalaena glacialis), southern right (Eubalaena australis),

pygmy right (Capera marginata), and gray whales (Eschrichtius

robustus).

The odontocetes (toothed whales) that may be affected because they

inhabit the deeper, offshore waters where SURTASS LFA sonar might

operate include both the pelagic (oceanic) whales and dolphins and

those coastal species that also occur in deep water including Stenella

spp., Risso's dolphin (Grampus griseus), rough-toothed dolphin (Steno

bredanensis), Fraser's dolphin (Lagenodelphis hosei), right-whale

dolphin (Lissodelphis spp.), Lagenorhynchus spp., Cephalorhynchus spp.,

bottlenose dolphin (Tursiops truncatus), common dolphin (Delphinus

delphis), Dall's porpoise (Phocoenoides dalli), melon-headed whale

(Peponocephala spp.), beaked whales (Berardius spp., Hyperoodon spp.,

Mesoplodon spp., Cuvier's beaked whale (Ziphius cavirostris), Shepard's

beaked whale (Tasmacetus shepherdi), Longman's beaked whale

(Indopacetus pacificus), killer whale (Orcinus orca), false killer

whale (Pseudorca crassidens), pygmy killer whale (Feresa attenuata),

sperm whale (Physeter macrocephalus, Kogia spp.), and pilot whale

(Globicephala spp.).

Potentially affected pinnipeds include: 8 phocid (true seal)

species including, the Hawaiian and Mediterranean monk seals (Monachus

spp.), harbor seals (Phoca spp), and elephant seals (Mirounga spp.); 8

species of fur seals (Arctocephalus spp., Callorhinus ursinus); and 5

species of sea lions, including the Steller sea lion (Eumetopias

jubatus) and California sea lion (Zalophus californianus)

Potentially affected pinnipeds include: 8 phocid (true seal)

species including, the Hawaiian and Mediterranean monk seals (Monachus

spp.), harbor seals (Phoca spp), and elephant seals (Mirounga spp.); 8

species of fur seals (Arctocephalus spp., Callorhinus ursinus); and 5

species of sea lions, including the Steller sea lion (Eumetopias

jubatus) and California sea lion (Zalophus californianus).

A description of affected marine mammal species and the criteria

used to determine those species that have the potential for taking by

harassment are provided and explained in detail in the Navy application

and DEIS and need not be repeated here.

Impacts to Marine Mammals

The analysis of potential impacts on marine mammals was developed

by the Navy based on the results of a literature review, the Navy's LF

Sound Scientific Research Program (LFS SRP), and a complex,

comprehensive program of underwater acoustical modeling. To assess

potential impact of the SURTASS LFA sonar source on marine mammals

operating at a given site, it was necessary for the Navy to predict the

sound field that a given marine mammal species could be exposed to over

time. This is a multi-part process involving (1) the ability to measure

or estimate an animal's location in space and time, (2) the ability to

measure or estimate the three-dimensional sound field at these times

and locations, (3) the integration of these two data sets to estimate

the total acoustic exposure for each animal in the modeled population,

e mammal species could be exposed to over

time. This is a multi-part process involving (1) the ability to measure

or estimate an animal's location in space and time, (2) the ability to

measure or estimate the three-dimensional sound field at these times

and locations, (3) the integration of these two data sets to estimate

the total acoustic exposure for each animal in the modeled population,

(4) converting the resultant cumulative exposures for a modeled

population into an estimate of the risk from a prolonged disruption of

a biologically important behavior, and (5) converting these estimates

of behavioral risk into an assessment of risk in terms of the level of

potential biological removal.

Next, a relationship for converting the resultant cumulative

exposures for a modeled population into an estimate of the risk to the

entire population of a prolonged disruption of a biologically important

behavior and of injury was developed. This process assessed risk in

relation to received level (RL) and repeated exposure. The resultant

``risk continuum'' is based on the assumption that the threshold of

risk is variable and occurs over a range of conditions rather than at a

single threshold.

Taken together, the LFS SRP results, the acoustical modeling, and

the risk assessment, provide an estimate of potential environmental

impacts to marine mammals.

The acoustical modeling process was accomplished using the Navy's

standard acoustical performance prediction transmission loss model-

Parabolic Equation (PE) version 3.4. The results of this model are the

primary input to the Acoustic Integration Model (AIM). AIM was used to

estimate mammal sound exposures and essentially integrates simulated

movements (including dive patterns) of marine mammals, a schedule of

SURTASS LFA sonar transmissions, and the predicted sound field for each

transmission to estimate acoustic exposure during a hypothetical

SURTASS LFA sonar operation

f this model are the

primary input to the Acoustic Integration Model (AIM). AIM was used to

estimate mammal sound exposures and essentially integrates simulated

movements (including dive patterns) of marine mammals, a schedule of

SURTASS LFA sonar transmissions, and the predicted sound field for each

transmission to estimate acoustic exposure during a hypothetical

SURTASS LFA sonar operation. Description of the PE and AIM models,

including AIM input parameters for animal movement, diving behavior,

and marine mammal distribution, abundance, and density are described in

detail in the Navy application and the DEIS and are not discussed

further in this document.

Using the AIM model, the Navy developed 31 acoustic modeling

scenarios for the major ocean regions (which are described in the

application and DEIS). Locations were carefully selected to represent

reasonable ``worst case'' scenarios for each of the three major ocean

acoustic regimes where SURTASS LFA sonar would be employed. These

acoustic regimes were (1) deep-water convergence propagation zone, (2)

near surface duct propagation zone, and (3) shallow water bottom

interaction propagation zone. These scenarios represent the condition

under

which, on average, the greatest number of animals could be exposed to

the greatest number of pings at the highest RLs and were considered the

most severe conditions that could be expected from operation of the

SURTASS LFA sonar system. Thus, if SURTASS LFA sonar operations were

conducted in an area that was not acoustically modeled, the potential

effects would almost certainly be less than those obtained from the

most similar scenario in the analysis.

Risk Analysis

reatest number of pings at the highest RLs and were considered the

most severe conditions that could be expected from operation of the

SURTASS LFA sonar system. Thus, if SURTASS LFA sonar operations were

conducted in an area that was not acoustically modeled, the potential

effects would almost certainly be less than those obtained from the

most similar scenario in the analysis.

Risk Analysis

The Navy interprets the results of the LFS SRP to justify use of

unlimited exposure during a mission to 120 dB as the lowest value for

risk. Below this level, there is no risk of prolonged biologically

significant responses from marine mammals. It is important to note that

risk varies with both level and number of exposures.

The Navy calculated the risks for take by injury based on criteria

of 180 dB RL, which is a conservative value for the onset of a minor

temporary threshold (TTS) shift in hearing (see Ridgway et al. (1997)).

Ridgway et al.'s (1997) measurement at one second duration implies that

the TTS threshold for a 100-second signal lies between 182 and 172 dB,

depending upon the formula used. The Navy believes that the 180-dB

single ping criterion can be considered conservative. However, the RL

for serious injury would be much higher, and the marine mammal would

have to be much closer to the array than the 2 km (1.1 nm) radius

around the vertical array delineating the 180 dB sound field. With

three levels of mitigation monitoring for marine mammals (described

later in this document), it is unlikely that any marine mammal would

get that close before either turning away from the annoyance, or being

detected and the SURTASS LFA sonar shut down (see Mitigation). However,

because the probability is not zero, the Navy has included this

scenario in its authorization request.

Mitigation and Monitoring

f mitigation monitoring for marine mammals (described

later in this document), it is unlikely that any marine mammal would

get that close before either turning away from the annoyance, or being

detected and the SURTASS LFA sonar shut down (see Mitigation). However,

because the probability is not zero, the Navy has included this

scenario in its authorization request.

Mitigation and Monitoring

SURTASS LFA sonar operations would be conducted to ensure that the

sound field does not exceed 180 dB re 1 Parms

(i.e., the zone of potential injury for marine mammals) within 22 km

(12 nm) of any coastline, nor in offshore biologically important areas

that are outside the 22 km (12 nm) zone during the biologically

important season(s) for that particular area.

SURTASS LFA sonar operators would estimate sound pressure levels

prior to and during operations to provide the information necessary to

modify operations, including delay or suspension of transmissions, in

order not to exceed the sound field criteria. Please refer to the

Navy's application for the criteria used to determine biologically

important areas.

In order to minimize risks to potentially affected marine mammals

that may be present in waters surrounding SURTASS LFA sonar, the Navy

will: (1) Conduct visual monitoring from the ship's bridge during

daylight hours, (2) use passive (LF) SURTASS LFA sonar to listen for

vocalizing marine mammals; and (3) use high frequency (HF) active sonar

(i.e., commercial fish finder) to monitor/locate/track marine mammals

in relation to the SURTASS LFA sonar vessel and the sound field

produced by the SURTASS LFA sonar source array.

Through observation, acoustic tracking and establishment of shut-

down criteria, the Navy will ensure that no marine mammals approach the

SURTASS LFA sonar source close enough to be subjected to potentially

harmful sound levels (inside the 180 dB re 1 Parms

sound field; approximately 2 km (1.1 nm) from the source)

onar vessel and the sound field

produced by the SURTASS LFA sonar source array.

Through observation, acoustic tracking and establishment of shut-

down criteria, the Navy will ensure that no marine mammals approach the

SURTASS LFA sonar source close enough to be subjected to potentially

harmful sound levels (inside the 180 dB re 1 Parms

sound field; approximately 2 km (1.1 nm) from the source). The Navy

estimates that the probability of detecting a marine mammal within the

180 dB sound field of the source array by at least one of these

monitoring methods is estimated to be between 70 and 99 percent.

However, nominally, an effectiveness of 80 percent is used in the take

calculations. This assumption incorporates the 70 percent effectiveness

of the HF sonar, and an additional conservative 5- percent contribution

each for visual and passive monitoring. In general, small, solitary

marine mammals would be the most difficult to detect, while large

whales and dolphin schools would be much easier to detect.

Reporting

During routine operations of SURTASS LFA sonar, technical and

environmental data would be collected and recorded. These would include

data from visual and acoustic monitoring, ocean environmental

measurements, and technical operational inputs. This information would

become part of the data required from the Long Term Monitoring (LTM)

Program.

Research

The Navy proposes to provide a LTM program to conduct annual

assessments of the potential cumulative impact of SURTASS LFA sonar

operations on the marine environment, provide the necessary reporting

to increase knowledge of the species, and to coordinate research

opportunities and activities. This would include cumulative impact

analyses of the annually tabulated injuries (if any) and harassments

over the next 5 years.

While research conducted to date is sufficient to assess impacts on

marine mammals, it is prudent to continue research over the course of

the first 5 years of the Navy's operations of SURTASS LFA sonar

ecies, and to coordinate research

opportunities and activities. This would include cumulative impact

analyses of the annually tabulated injuries (if any) and harassments

over the next 5 years.

While research conducted to date is sufficient to assess impacts on

marine mammals, it is prudent to continue research over the course of

the first 5 years of the Navy's operations of SURTASS LFA sonar.

The purpose of the LTM program would be to continue scientific data

collection once SURTASS LFA sonar is deployed.

Conclusions

Based on the scientific analyses detailed in the Navy application

and further supported by the DEIS for SURTASS LFA sonar operations, the

Navy concludes that the incidental taking of marine mammals resulting

from SURTASS LFA sonar operations would be small and have no more than

a negligible impact on the affected marine mammal stocks or habitats.

This conclusion is particularly supported by the proposed mitigation

measures that would be implemented for all SURTASS LFA sonar operations

and the proposed LTM program. The former includes geographic

restrictions, monitoring and reporting that would result in increased

knowledge of marine mammal species. The latter offers means of learning

of, encouraging, and coordinating research opportunities, plans, and

activities relating to reducing the incidental taking of marine mammals

from anthropogenic underwater sound, and evaluating the possible long-

term effects from exposing marine mammals to anthropogenic underwater

sound.

Information Solicited

n increased

knowledge of marine mammal species. The latter offers means of learning

of, encouraging, and coordinating research opportunities, plans, and

activities relating to reducing the incidental taking of marine mammals

from anthropogenic underwater sound, and evaluating the possible long-

term effects from exposing marine mammals to anthropogenic underwater

sound.

Information Solicited

NMFS requests interested persons to submit comments, information,

and suggestions concerning the Navy's request for a single LOA valid

for SURTASS LFA sonar operations in all 10 biogeographic regions, and

the structure and content of the regulations to allow takings by LFA

sonar operations. NMFS would propose a single set of regulations,

effective for a period of time up to 5 years, that would govern

incidental takings for LFA sonar operations. All commenters are

requested to review the DEIS and/or the application prior to submitting

comments and, because of its brevity, not submit comments solely on

this Federal Register document.

NMFS is also requesting comment on an alternative proposal to issue

annual LOAs to each vessel as it becomes operational. Based upon

applications for annual LOAs, individual vessel LOAs

may specify which of the 10 operating areas were scheduled for the

upcoming year. For security reasons, locations and times for certain

operations may be classified and not provided to the public.

If NMFS proposes regulations governing the taking, interested

parties will be provided a 45-day comment period on the content of the

proposed rule.

This action has been determined to be not significant for purposes

of Executive Order 12866.

Dated: October 15, 1999.

Andrew A. Rosenberg,

Deputy Assistant Administrator for Fisheries, National Marine Fisheries

Service.

[FR Doc. 99-27579 Filed 10-21-99; 8:45 am]

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