Small Takes of Marine Mammals Incidental to Specified Activities; McDonnell Douglas Aerospace Delta II Vehicles at Vandenberg Air Force Base, CA

DEPARTMENT OF COMMERCE

National Oceanic and Atmospheric Administration

[I.D. 081696A]

Small Takes of Marine Mammals Incidental to Specified Activities;

McDonnell Douglas Aerospace Delta II Vehicles at Vandenberg Air Force

Base, CA

AGENCY: National Marine Fisheries Service (NMFS), National Oceanic and

Atmospheric Administration (NOAA), Commerce.

ACTION: Notice of receipt of application and proposed authorization for

a small take exemption; request for comments.

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SUMMARY: NMFS has received a request from the U.S. Air Force for

continuation of an authorization to take small numbers of harbor seals

by harassment incidental to launches of McDonnell Douglas Aerospace

(MDA) Delta II (Delta II) vehicles at Space Launch Complex 2W (SLC-2W),

Vandenberg Air Force Base, CA (Vandenberg). Under the Marine Mammal

Protection Act (MMPA), NMFS is requesting comments on its proposal to

authorize the Air Force to incidentally take, by harassment, small

numbers of harbor seals, California sea lions and northern elephant

seals in the vicinity of Vandenberg for a period of 1 year.

DATES: Comments and information must be received no later than

September 30, 1996.

ADDRESSES: Comments on the application should be addressed to Michael

Payne, Chief, Marine Mammal Division, Office of Protected Resources,

National Marine Fisheries Service, 1315 East-West Highway, Silver

Spring, MD 20910. A copy of the application, a list of the references

used in this document, and/or previous Federal Register notices on this

activity may be obtained by writing to this address or by telephoning

one of the contacts listed below.

FOR FURTHER INFORMATION CONTACT: Kenneth Hollingshead, Office of

Protected Resources at 301-713-2055, or Irma Lagomarsino, Southwest

Regional Office at 310-980-4016.

SUPPLEMENTARY INFORMATION:

Background

Section 101(a)(5)(A) of the MMPA (16 U.S.C. 1361 et seq.) directs

NMFS 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.

[[Page 45405]]

Permission may be granted if NMFS finds that the taking will have a

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

unmitigable adverse impact on the availability of the species or

stock(s) for subsistence uses, and the permissible methods of taking

and requirements pertaining to the monitoring and reporting of such

taking are set forth.

Subsection 101(a)(5)(D) of the MMPA established an expedited

process by which U.S. citizens can apply for an authorization to

incidentally take small numbers of marine mammals by harassment for a

period of up to 1 year. The MMPA defines ``harassment'' as:

* * *any act of pursuit, torment, or annoyance which (a) has

the potential to injure a marine mammal or marine mammal stock in

the wild; or (b) 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.

Subsection 101(a)(5)(D) establishes a 45-day time limit for NMFS

review of an application followed by a 30-day public notice and comment

period on any proposed authorizations for the incidental harassment of

small numbers of marine mammals. Within 45 days of the close of the

comment period, NMFS must either issue or deny issuance of the

authorization.

Summary of Request

On July 17, 1996, NMFS received an application from the U.S. Air

Force requesting continuation of an authorization for the harassment of

small numbers of harbor seals and potentially for other pinniped

species incidental to launches of Delta II vehicles at SLC-2W,

Vandenberg. These launches would place Department of Defense, National

Aeronautics and Space Administration (NASA), and commercial medium-

weight payloads into polar or near-polar orbits. MDA/NASA intends to

launch up to 10 Delta IIs during the period of this proposed 1-year

authorization.

Because SLC-2W is located north of most other launch complexes at

Vandenberg, and because there are oil production platforms located off

the coast to the south of SLC-2W, missions flown from SLC-2W cannot fly

directly on their final southward course. The normal trajectory for a

SLC-2W launch is 259.50 deg. west for the first 90 seconds, then a 41-

second dog-leg maneuver to bring the vehicle on its southward course of

196 deg.. This trajectory takes the launch vehicle away from the coast

and nearly 30 mi west of San Miguel Island (SMI), the westernmost

Channel Island (Air Force, 1995b)1.

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\1\ A list of references used in this document can be obtained

by writing to the address provided above (see ADDRESSES).

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Description of Habitat and Marine Mammals Affected by Delta IIs

The Southern California Bight (SCB), including the Channel Islands

area, support a diverse assemblage of pinnipeds (seals and sea lions)

and cetaceans (whales, dolphins, and porpoises). California sea lions

(Zalophus californianus), northern elephant seals (Mirounga

angustirostris), harbor seals (Phoca vitulina) and northern fur seals

(Callorhinus ursinus) breed on the Islands, with the largest rookeries

on SMI and San Nicolas Island.

A small breeding population of California sea lions occurs on

Vandenberg and both sea lions and northern elephant seals are regular

visitors to the shoreline near SLC-2W. A small population of harbor

seals are normal residents of Purisima Point adjacent to SLC-2W and

southern sea otters (Enhydra lutra) were censused there during the

spring of 19952.

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\2\ Sea otters are under the jurisdiction of the U.S. Fish and

Wildlife Service (USFWS) and not NMFS. Discussions between the

applicant and the USFWS have taken place. Please contact those

agencies for additional information.

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Because it is the only species that hauls out along the Vandenberg

coast, the only marine mammal anticipated to be incidentally harassed

by Delta II launches is the harbor seal. A description of the SCB

population of harbor seals and other pinniped species was provided on

August 18, 1995, in conjunction with publication of the previous notice

of application for this activity (60 FR 43120) and is therefore not

repeated here. Only new information on harbor seals is provided below.

Interested reviewers are encouraged to refer to the document cited

above for the appropriate discussion. That document is also available

from NMFS (see ADDRESSES).

Harbor seals are considered abundant throughout most of their range

and have increased substantially in the last 20 years. Hanan and Beeson

(1994) reported 21,462 seals counted on the mainland coast and islands

of California during May and June, 1994. Using that count and Huber et

al.'s (1993) correction factor (1.61 times the count) for animals not

hauled out gives a best population estimate of 34,554 harbor seals in

California (Barlow et al. 1995).

Vandenberg supports a substantial population of harbor seals. A

total of 19 distinct haulout sites are present on Vandenberg (between

Point Sal and Jalama Beach), although not all sites are used regularly

(Roest 1995). For most of the year, the average number of harbor seals

on the Vandenberg coast is about 330 individuals. This number nearly

doubles during the molting season (June) to roughly 610. The largest

population occurs on South Vandenberg, although a smaller permanent

population is present at two sites near Purisima Point on North

Vandenberg. Based on aerial surveys completed between 1983 and 1993 in

May or June by the California Department of Fish and Game, harbor seal

populations on Vandenberg varied from a low of 139 in 1983 to a high of

864 in 1990 (Roest 1995). Some variability in numbers may be due to

actual changes in population densities while others may be due to

refinement in techniques for completing the aerial surveys. In general,

it appears that the current population of harbor seals at all 19

haulout sites on Vandenberg peaks at roughly 600 to 800 seals (Air

Force 1996).

Maximum numbers of harbor seals at Purisima Point in May/June

average about 40 while the Spur Road site seems to have an average

maximum of from 60 to 80 individuals. More than other sites, Spur Road

appears to have peak numbers in the fall (Air Force 1996, Roest 1995).

However, both sites are submerged at high tide, making them unavailable

to harbor seals during those times.

Potential Effects of Delta II Launches on Marine Mammals

As a result of the noise associated with the launch itself, there

is a potential to cause a startle response to those harbor seals and

other pinnipeds that may haul out on the coastline of North Vandenberg,

principally Purisima Point and Spur Road. Launch noise would be

expected to occur over the coastal habitats in the vicinity of SLC-2W

while low-level sonic booms could be heard over the water in the area

west of the Channel Islands.

The effect on pinnipeds would be disturbance by sound, which is

anticipated to result in a negligible short-term impact to the small

number of harbor seals and other pinnipeds that may be hauled out along

the coast near SLC-2W at the time of Delta II launches. NMFS is unaware

of any evidence that any marine mammals, other than those onshore at

the time of launch, would be subject to harassment by launch noises,

although the potential does exist that marine mammal species may hear

either the launch noise or the sonic boom. In addition, because of the

mostly

[[Page 45406]]

horizontal propagation of launch noise, little noise is expected to

penetrate the water interface.

At North Vandenberg, launch noises are expected to impact mostly

harbor seals, as other pinniped species (California sea lions and

northern elephant seals) are known to haul out at these sites only

infrequently and in smaller numbers. Based upon measurements made in

1995 (Aerospace Corporation 1996), the maximum overall sound pressure

levels from launch noise associated with the Delta II under typical

conditions is predicted to be about 115 dBA (129 dB unweighted)(re

20Pa @ 1 m) at the nearest potential harbor seal haulout

(3,000 ft (914.4 m) from launch site) and 110 dBA (125 dB) at Purisima

Point (5,000 ft (1,524 m) from launch site) and last for approximately

1 minute.

Because of high-tide and pre-dawn conditions at the time of the two

previous launches of Delta IIs at Vandenberg, few to no seals were

expected to be ashore at these launch times. However, based upon

monitoring 3 days prior to, and after, these launches, there appeared

to be no differences in the number of harbor seals using these sites

for hauling out before and after launchings of Delta IIs (Air Force

1996).

As a result of the launch of a Taurus rocket (slightly smaller in

size to the Delta II) in March 1994 at SLC-2W, Stewart et al. (1994)

observed that 20 of 23 harbor seals on Purisima Point fled into the

water. The A-weighted sound exposure level at Purisima Point for that

launch was 108.1 dB (127.5 dB unweighted). Therefore, it can be

predicted that most, if not all, pinnipeds onshore near SLC-2W will

leave the shore as a result of launchings of Delta IIs. Harbor seals

and other pinnipeds, hauled out at Point Arguello and Rocky Point

(approximately 15 mi (24.1 km) south of SLC-2W), may alert to the

launch noise but are not expected to flee to the water, because of the

distance and the resultant attenuation of launch noise at that

distance.

Launch noises are not expected to impact marine mammals offshore,

although pinnipeds in the nearshore waters around SLC-2W may alert to

the noise, and some may possibly submerge. In order to be detectable by

a marine mammal, airborne noise needs to be greater than ambient within

the same frequency as the animal's hearing range. For harbor seals,

recent research (Terhune 1988, Turnbull and Terhune 1989, Terhune 1991,

Turnbull 1994) indicates that harbor seals have relatively poor hearing

capacity in the frequencies of sound that dominate the noise produced

by a rocket launch. At the lowest frequency measured (100 Hz), the

threshold was between 65 dB and 75 dB. Terhune (1991) indicated that

the critical ratio at the lowest frequency measured (250 Hz) was 24 dB.

Thus, noise would need to be roughly 24 dB or more above background to

be perceived by a harbor seal. With launch noises expected to quickly

attenuate offshore, and with ambient noise level expected to range

between 56 and 96 dBA (Air Force, 1995a), there is presently reasonable

expectation that no marine mammals, other than pinnipeds onshore at the

time of launch, would be subject to harassment by launch noises,

although the potential does exist that other marine mammal species may

hear the launch noise. However, simply hearing the noise does not mean

that the animals have been harassed.

Northern Channel Islands

Sonic booms resulting from launches of the Delta II vary with the

vehicle trajectory and the specific ground location. Sonic booms are

not expected to intersect with the ocean surface until the vehicle

changes its launch trajectory. This location will be well offshore.

Depending upon the intensity and location of a sonic boom,

pinnipeds on SMI could exhibit an alert response or stampede into the

water. However, while it is highly probable that a sonic boom from the

Delta II would occur over SMI, maximum overpressures of these sonic

booms are estimated to be 1.0 lb/ft2 (psf) over SMI (Air Force

1995c). A sonic boom with an overpressure of 1.0 psf or less is not

considered significant (equivalent to hearing two hands clapped

together at a distance of 1 ft). Also, the maximum overall sound

pressure level is not expected to exceed 78 dBA (112 dB) (Air Force

1995c). A sonic boom of this magnitude is unlikely to be

distinguishable from background noises caused by wind and surf (Air

Force 1995a). Monitoring of the effects of noise generated from Titan

IV launches on SMI pinnipeds in 1991, Stewart et al. (1992)

demonstrated that noise levels from a sonic boom of 133 dB (111.7 dBA)

caused an alert response by small numbers of California sea lions, but

no response from other pinniped species present (including harbor

seals). In 1993, an explosion of a Titan IV created a sonic boom-like

pressure wave and caused approximately 45 percent of the California sea

lions (approximately 23,400, including 14,000-15,000 1-month old pups,

were hauled out on SMI during the launch) and 2 percent of the northern

fur seals to enter the surf zone. Although approximately 15 percent of

the sea lion pups were temporarily abandoned when their mothers fled

into the surf, no injuries or mortalities were observed. Most animals

were returning to shore within 2 hours of the disturbance (Stewart et

al. 1993).

Since the noise level from Delta II launches is expected to be well

below both these levels and the threshold criteria of 101 dBA

identified by Stewart et al. (1993), no incidental harassment takings

are anticipated to occur on the northern Channel Islands.

Cetaceans and pinnipeds in the water should also be unaffected by

the sonic booms, although, depending upon location and ambient noise

levels, some species may be able to hear the sonic boom. While the

maximum magnitude of sonic booms from launches of the Delta II is

unknown, because of its similarity in size and weight to the Lockheed

launch vehicles (LLV) (see 60 FR 38308, July 26, 1995), the sonic boom

signature from the largest of those vehicles (LLV-3--3.5 psf/125.6 dB),

can be used to predict the impact by the Delta II. Pressure levels of

this magnitude would be less than those measured for other launch

vehicles, such as the Titan IV and the Space Shuttle, for which small

take authorizations for harassment have been issued previously (see 56

FR 41628, August 22, 1991 and 51 FR 11737, April 7, 1986).

Although rough seas may provide some surfaces, at the proper angle,

for sound to penetrate the water surface (Richardson et al. 1991,

1995), sound entering a water surface at an angle greater than 130 deg.

from the vertical has been shown to be largely deflected at the

surface, with very little sound entering the water (Chappell 1980,

Richardson et al. 1991). Chappell (1980) believes that a sonic boom

would need to have a peak overpressure in the range of 138 to 169 dB to

cause a temporary hearing threshold shift (TTS) in marine mammals,

lasting at most a few minutes. Therefore, with only a remote likelihood

that a marine mammal will be almost directly under the line of flight

of the Delta II, and with the Delta II having overpressures below the

threshold for potentially causing TTS in marine mammals, NMFS believes

that sonic booms are not likely to result in the harassment of, or

injury to, cetacean or pinniped populations in offshore waters of the

SCB.

Mitigation

Unless constrained by other factors including, but not limited to,

human safety, national security or launch

[[Page 45407]]

trajectories, efforts to ensure minimum negligible impacts of Delta II

launches on harbor seals and other pinnipeds are proposed for inclusion

in the Incidental Harassment Authorization. These proposals include:

1. Avoidance whenever possible of launches during the harbor seal

pupping season of February through May; and

2. Preference for night launches during the period of the year when

harbor seals are hauled out in any numbers along the coast of North

Vandenberg.

Monitoring

NMFS proposes that the holder of the Incidental Harassment

Authorization would monitor the impact of Delta II launches on the

harbor seal haulouts in the vicinity of Spur Road and Purisima Point.

The applicant proposes to conduct at least 3 sets of seal abundance and

behavioral observations with the first no more than 7 days prior to the

launch and the final set as soon as practicable after the launch. Video

monitoring of daylight launches would also be required. A report on

this monitoring program would be required to be submitted prior to next

year's authorization request, unless the monitoring indicated that

serious injuries or mortalities had occurred that might relate to the

launching. In this case, the authorization would require immediate

notification of this fact to the Southwest Regional Director, NMFS.

Conclusions

The short-term impact of the launching of Delta II rockets is

expected to result at worst, in a temporary reduction in utilization of

the haulout as seals or sea lions leave the beach for the safety of the

water. Launchings are not expected to result in any reduction in the

number of pinnipeds, and they are expected to continue to occupy the

same area. In addition, there will not be any impact on the habitat

itself. Based upon studies conducted for previous space vehicle

launches at Vandenberg, significant long-term impacts on pinnipeds at

Vandenberg and the northern Channel Islands are unlikely.

Proposed Authorization

NMFS proposes to issue an incidental harassment authorization for 1

year for launches of the Delta II rocket at SLC-2W, provided the above-

mentioned monitoring and reporting requirements are incorporated. NMFS

has preliminarily determined that the proposed launches of the Delta II

at SLC-2W would result in the harassment taking of only small numbers

of harbor seals and possibly other pinniped species, will have a

negligible impact on pinniped stocks in the SCB and will not have an

unmitigable adverse impact on the availability of these stocks for

subsistence uses.

Information Solicited

NMFS requests interested persons to submit comments, information,

and suggestions concerning this request (see ADDRESSES).

Dated: August 23, 1996.

Rennie S. Holt,

Acting Director, Office of Protected Resources, National Marine

Fisheries Service.

[FR Doc. 96-22057 Filed 8-28-96; 8:45 am]

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