Small Takes of Marine Mammals Incidental to Specified Activities; Explosives Testing at Eglin Air Force Base, FL

Summary:

NMFS has received a request from the U.S. Air Force to take, by harassment, bottlenose dolphins, and spotted dolphins incidental to explosive testing of obstacle and mine clearance systems at Eglin Air Force Base, FL (Eglin). Under the Marine Mammal Protection Act (MMPA), NMFS is requesting comments on its proposal to authorize these takings for a period not to exceed 1 year.

Table of Contents

Dates:

Comments and information must be received no later than November 20, 2000. Comments will not be accepted if submitted via e-mail or the Internet.

Addresses:

Comments on this application should be addressed to Donna Wieting, Chief, Marine Mammal Conservation Division, Office of Protected Resources, NMFS, 1315 East-West Highway, Silver Spring, MD 20910. A copy of the application, the Environmental Assessment (EA), and/or a list of references used in this document, may be obtained by writing to this address or by telephoning one of the contacts listed here.

For further information contact:

Kenneth Hollingshead 301-713-2055 ext. 128, or Kathy Wang, 727-570-5312.

Supplementary information:

Background

Sections 101(a)(5)(A) and (D) of the MMPA (16 U.S.C. 1361 et seq.) directs the Secretary of Commerce to allow, upon request, the incidental, but not intentional, taking of small numbers 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 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.

Permission may be granted if NMFS finds that the taking will have a negligible impact on the affected species or stock(s) of marine mammals, will not have an unmitigable adverse impact on the availability of the species or stock(s) for subsistence uses, and if permissible methods of taking and requirements pertaining to the 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.”

Subsection 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. 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 August 6, 2000, NMFS received an application from the U.S. Air Force at Eglin. The Air Force, in cooperation with the Naval Surface Warfare Center-Coastal Systems Station (NSWC-CSS), U.S. Navy, is requesting an authorization to take, by harassment and non-serious injury, bottlenose dolphins (Tursiops truncatus), and spotted dolphins (Stenella frontalis) incidental to explosive testing of an obstacle clearance system at Eglin. Eglin is located in the Florida Panhandle approximately midway between the cities of Pensacola and Panama City, FL. The location of the proposed action is on the beach areas on Santa Rosa Island (SRI), approximately 27 kilometers (km)(17 mi) west of Destin, FL.

The Navy’s current capability to clear obstacles and mines in the surf zone is limited to the hand placement of explosive charges by Navy combat swimmers. The effectiveness of this capability is limited by the ability of swimmers to locate submerged targets and to carry sufficient explosives to destroy the targets. Such operations are considered highly hazardous, and the reliability of obstacle removal is considered to be poor. During the Gulf War, U.S. forces were prevented from landing on the beaches of Kuwait because of the nature and density of the mines and obstacles present on the beaches and in the shallow surf zone. To facilitate future amphibious assaults, the U.S. Navy is committed to developing and testing methods to safely and effectively clear a path through such obstacles, allowing U.S. Marines to conduct an amphibious assault.

NWSC-CSS has requested permission from Eglin to test the Mk-82 general purpose bomb (GPB) in the shallow surf zone along U.S. Air Force-controlled lands of SRI. The taking of bottlenose and spotted dolphins incidental to testing the Shallow Water Assault Breaching system, the Distributed Explosive Technology system, the MK-82 GPBs, and the MK-5 Mine Clearance System (MCS) was authorized by NMFS in December, 1998 (see 63 FR 67669, December 8, 1998). That authorization expired on March 31, 1999. However, testing of the Mk-82 GPB was not conducted during that authorization period.

The proposed action by the NSWC-CSS is an evaluation of the Mk-82 GPBs to clear anti-invasion beach obstacles and mines in the surf zone. The objectives of the test are to: (1) determine the performance of the Mk-82 GPBs against threat obstacles and mines in the surf zone, and (2) provide data and verify empirical models used to assess surf zone obstacle and mine clearance.

The MK-82 GPBs to be tested consist of seven GPBs, each containing 192 lbs (87.1 kg) of explosive for a total weight of 1,344 lbs (610 kg). Three configurations for testing will be used for the proposed test: (1) A linear arrangement of seven GPBs spaced 24 ft (7.3 m) apart, located parallel to the shoreline, (2) a linear arrangement of 7 GPBs spaced 24 ft (7.3 m) apart located perpendicular to the shore, and (3) a matrix (2-3-2) arrangement.

Two separate deployments and firings are required to test each configuration. All MK-82s will be buried vertically to approximately one-half length (about 3 ft (0.9 m)) by jetting. The MK-82s will be detonated using approximately 1/4 block of C-4 explosive paced into the aft fuse well. The MK-82s will be detonated simultaneously in 6 ft (1.8 m) of water using remote detonators to detonate the C-4. All Mk-82 GPBs will be placed in shallow water in the surf zone between the shore and the sand bar.

Each test event will require several days to set up. Beach obstacles (log posts, concrete cubes, and steel hedgehogs) and inert mines will be placed around the bombs to serve as targets for bomb fragments and blast. The Mk-82 GPBs will be detonated and the obstacles and mine field scored and cleaned up to the extent feasible.

In order to avoid impacting the endangered West Indian manatee (Trichiechus manatus)(which is more commonly found south of the region and during warmer months) and sea turtles, tests are planned to be conducted between November 2000 and March, 2001.

More detailed descriptions of the activity and the expected impact on marine mammals can be found in the Air Force Incidental Harassment (IHA) application. Additional information can be found in the EA prepared in 1998 by the Air Force under the National Environmental Policy Act (NEPA). These documents are available upon request (see ADDRESSES).

Description of Habitat and Marine Mammals Affected by the Activity

A description of the eastern Gulf of Mexico (GOM) ecosystems can be found in general biological oceanographicreferences and in the previously mentioned EA and is not repeated here.

Marine Mammals

Although approximately 27 species of marine mammals (whales, dolphins and porpoises) reside in or pass through the northeastern GOM, the only species of marine mammals that are likely to be impacted by the activities proposed for the shallow coastal waters off SRI are the bottlenose dolphin (Tursiops truncatus) and the Atlantic spotted dolphin (Stenella frontalis). Information on these and other species of marine mammals in the GOM can be found in Blaylock et al. (1995) and Waring et al. (1999). Please refer to those documents for information on the biology, distribution, and abundance of these marine mammal species. Information on the two species of marine mammals that potentially may be affected can also be found in the application and EA on this project.

Potential Effects of Explosives on Marine Mammals

Potential impacts to those marine mammal species known to occur in the SRI area from explosives include both lethal and non-lethal injury, as well as incidental harassment. The pressure wave from the explosive can impact air cavities, such as lungs and intestines. Extensive hemorrhaging into the lungs due to underwater shock waves may cause death to a marine mammal through suffocation (Hill, 1978). Other common injuries which may result in mortality include circulatory failure, broncho-pneumonia in damaged lungs, or peritonitis resulting from perforations of the intestinal wall (Hill, 1978). Because impulse levels sufficient to cause lethal injury increase with increased mammal mass (Yelverton et al., 1973), conservative criteria are based on the lowest possible affected mammalian weight (e.g., an infant dolphin). Extensive lung hemorrhage is an injury which would be debilitating, and not all animals would be expected to survive (1 percent mortality is predicted at the onset level). As the severity of extensive lung hemorrhage increases beyond the onset level, gastro-intestinal tract injuries can increase significantly. The expected mortality level associated with these combined severe injuries would be significantly higher than 1 percent (U.S. Navy, 1998).

Non-lethal injuries involve slight lung hemorrhage and tympanic membrane (TM) rupture from which the mammal is expected to recover (Yelverton et al., 1973; Richmond et al., 1973). Eardrum damage criteria are based upon a limited number of small charge tests (Yelverton et al., 1973; Richmond et al.,1973). Ranges for percent TM rupture incurred by underwater explosives can be calculated by a conservative TM damage model (U.S. Navy, 1996). General criteria for TM damage has been reported to occur at impulse levels down to 20 psi-msec (Yelverton et al., 1973).

Because TM rupture, rather than slight lung hemorrhage, usually occurs at lower impulse levels, TM rupture is used by NMFS and others to conservatively define the non-lethal injury zone. A maximum impulse of 10 psi-msec is often considered to define the non-lethal injury zone, where a very low incidence of blast injuries are likely to occur (Yelverton et al., 1973). A level of pressure impulse at which marine mammals are not expected to experience non-lethal injury (nor instantaneous mortality or lethal injury) is reported to be 5 psi-msec (Yelverton et al., 1973). This is the impulse level adopted by the Air Force to designate no injurious takings by its proposed activity.

In addition to lethal, serious, and non-serious injury, harassment of marine mammals may occur as a result of non-injurious physiological responses to an explosion-generated shockwave and its acoustic signature. Based upon information provided in the SEAWOLF shock trial final environmental impact statement (U.S. Navy, 1998), a dual criterion for marine mammal acoustic harassment has been developed for explosive-generated signals: (1) an energy-based temporary threshold shift (TTS) injury criterion of 182 dB re 1 uPa [2] -sec derived by the Navy from experiments with bottlenose dolphins by Ridgway et al.(1997), and (2) a 12 lbs/in [2] (psi) peak pressure cited by Ketten (1995) as associated with a “safe outer limit (for the 10,000 lb charge for minimal, recoverable auditory trauma” (i.e., TTS)). While recognizing that while there is some disagreement in the scientific community on criteria for predicting auditory impacts on marine mammals, for the activity described in this document, the Air Force and NMFS are retaining the determinations made for this action previously (see 63 FR 67669, December 8, 1998), that noise levels that fall between the 5 psi-msec distance out to a transmission distance where a noise level of 180 dB re 1 uPa [2] -sec (Air Force, 1998, 2000) will be considered to fall within the incidental harassment zone. It should be recognized however, that because the Air Force utilized the noise level of 180 dB re 1 uPa [2] -sec, instead of the previously mentioned level of 182 dB re 1 uPa2-sec, for modeling the proposed test activities, it will use the more precautionary level for estimating potential harassment.

The potential impact to Atlantic bottlenose dolphins and the Atlantic spotted dolphins, the two species that may potentially be affected, was evaluated using modeling on the effects of underwater explosions resulting from each of the test systems described previously (see application). Based upon data provided in the application, the maximum number of Atlantic bottlenose dolphins potentially within the injury exposure zone from all tests during the 4-month test period is estimated to be 27-28. The maximum number of Atlantic spotted dolphins potentially injured from all tests combined is less than 1. These are the maximum potential injury levels without implementation of mitigation.

The estimated total numbers of bottlenose dolphins and spotted dolphins potentially exposed to takes by harassment (because they may be within the area between 5 psi-msec and 180 dB re 1 uPa [2] -sec) are 19 and 1, respectively. However, mitigation is expected to obviate any potential for injury or harassment to marine mammals.

Mitigation

There are two forms of mitigation proposed for implementation by the Air Force: (1) Natural, as provided by the environment and (2) human, designed to protect marine mammals to the greatest extent practicable.

Natural mitigation: Physical characteristics of the proposed test area and test methods will ameliorate the underwater shock wave. Tests will be conducted in approximately 3 to 10 ft (0.9 to 3.0 m) of water. At this shallow depth, some portion of the energy from the detonations will be directed through the surface of the water rather than transmitted through the water. Another consequence of the shallow detonation depth is that bubble pulse is not significant and there will be far less energy in any oscillations, compared with deep water detonations (Shockley, 1995). Additionally, these tests will be conducted inside the offshore bar at the SRI site. The offshore bar ameliorates the transmission of the underwater portion of the shock wave. Also, MK-82 GPBs will be buried in bottom sands to approximately their center of gravity (3 ft (0.9 m)), a factor expected to mitigate the transmission of the shock wave as the detonations will be directed downwards.

Human mitigation: Eglin has established the following safety zones to prevent marine mammal injury fortesting MK-82 GPBs: (1) 6.0 km (3.7 mi) radius for the configuration parallel to beach and for the matrix; and (2) 5.0 km (3.1 mi) radius for the configuration perpendicular to the beach.

Eglin has proposed that base personnel conduct a 30-minute pre-detonation aerial monitoring survey immediately prior to each test to ensure no marine mammals are within the test area’s designated safety zone. With water depths less than 18 m (59 ft), low turbidity, and white sand bottom, exceptional marine mammal visibility is ensured. Aerial surveys will be conducted at approximately 100 ft (30.5 m) elevation.

In order to ensure adequate visibility for locating marine mammals (and sea turtles), no detonations will take place if sea state conditions are greater than category 3 and water clarity is not adequate for conducting surveys. No tests will take place if marine mammals or sea turtles are sighted within the safety zone.

Monitoring

In addition to pre-detonation monitoring mentioned previously, Eglin will conduct aerial surveys immediately following each detonation event. The post-test monitoring will be conducted in a similar manner to the pre-test monitoring, except that observation personnel will be focused on locating any injured marine mammals. If any injured marine mammals are observed during post-test monitoring, subsequent detonations will be postponed, and the local stranding network notified. The project will be required to be reviewed by Air Force and NMFS personnel prior to conducting any additional tests.

Reporting

Any takes of marine mammals other than authorized by the IHA will be reported to the Regional Administrator, NMFS, by the next working day. A draft final report of the entire test results and marine mammal observations for pre- and post-detonation monitoring will be submitted to NMFS within 90 days after completion of the last test. Unless notified by NMFS to the contrary, that draft final report will be considered the final report under the IHA.

NEPA

Previously, the U.S. Air Force prepared an EA on the Mk-82 GPB and Mk-5 MCS systems. This EA, which supplements information contained in the Air Force application provides additional information for determining whether the activity proposed for obtaining a small take authorization will have no more than a negligible impact on affected marine mammal stocks. NMFS reviewed the EA in December, 1998, and concurred with the findings in the EA (see 63 FR 67669, December 8, 1998). As a result, NMFS found that it is unnecessary to prepare its own NEPA documentation and adopted the Air Force EA as its own, as provided by 40 CFR 1506.3. At that time, NMFS found that the issuance of an IHA to the Air Force would not result in a significant environmental impact on the human environment and that it is unnecessary to either prepare its own NEPA documentation or to recirculate the Air Force EA for additional comments. NMFS believes that the findings made in December 1998, remain appropriate.

Consultation

On October 15, 1998, NMFS completed consultation with the Air Force under section 7 of the Endangered Species Act. The finding of that consultation was that the proposed testing activity is not likely to adversely affect endangered or threatened species of whales or sea turtles, if the conservation and mitigation measures specified in the Biological Assessment prepared by the Air Force are undertaken. NMFS concludes, therefore, that the issuance of an IHA to the Air Force to take small numbers of bottlenose dolphins, spotted dolphins and possibly other cetacean species by harassment incidental to explosive testing at Eglin is not likely to adversely affect endangered or threatened species of whales or sea turtles.

Proposed Authorization

NMFS proposes to issue an IHA to the U.S. Air Force for the harassment of a small number of bottlenose dolphins and spotted dolphins incidental to testing the Mk-82 GPBs off SRI, Eglin. NMFS has preliminarily determined that, provided the proposed mitigation and monitoring measures are enacted, the short-term impact of testing Mk-82 GPBs for obstacle and mine clearance systems at Eglin has the potential to result in only small numbers of marine mammals being affected, and have no more than a negligible impact on affected marine mammal stocks.

Information Solicited

NMFS requests interested persons to submit ments, information, and suggestions concerning this request (see ADDRESSES).

Dated: October 10, 2000. Art Jeffers,

Deputy Director, Office of Protected Resources, National Marine Fisheries Service.

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