Contact: Gordon Helm FOR IMMEDIATE RELEASE
5/31/96
The National Oceanic and Atmospheric Administration is seeking comment on an application and proposed authorization for BP Exploration (Alaska) of Anchorage, AK., to potentially disturb small numbers of marine mammals while conducting a seismic survey in the Northstar Unit of the Western Beaufort Sea in state and federal waters of Alaska.
Under the Marine Mammal Protection Act, BP Exploration applied for a permit to incidentally disturb small numbers of bowhead whales and other marine mammals during an oil and gas survey.
NOAAþs National Marine Fisheries Service may grant permission to incidentally harass these mammals if it finds that the survey will have a negligible impact on affected marine mammals and on the availability of some species for subsistence uses, and provided BP Exploration meets proposed mitigation, monitoring and reporting guidelines.
If approved, the survey is expected to take place between approximately July 20 and October 20, 1996, during the open water season in and near the Northstar Unit.
The Beaufort/Chukchi Seas support a diverse assembly of marine mammals, including bowhead whales, gray whales, beluga, ringed seals, spotted seals and bearded seals.
It is possible that the harvest of some marine mammals (mainly bowhead whales, ringed seals and bearded seals) by native hunters from coastal north slope communities may be affected. Movement of migrating marine mammals farther offshore, principally the bowhead and gray whales due to possible behavioral changes from elevated noise levels, could potentially make the subsistence harvest of these species more difficult.
Deep seismic surveys obtain data about formations several thousands of meters deep. These surveys are accomplished by transmitting sound waves into the earth, which are reflected off subsurface formations and recorded. A typical marine seismic source is an airgun array that releases compressed air into the water, creating an acoustical energy pulse that is directed into the earth. Hydrophones spaced along the ocean bottom receive the reflected energy from the subsurface formations and transmit the data to the surface vessels. On board, the signals are amplified, digitized and recorded on magnetic tape.
The airguns emit pulsed energy primarily at frequencies in the 10 to 300 Hz range. Dolphin, small whale, seal and sea lion hearing is believed to be poor at frequencies less than 1,000 Hz, and should be unaffected by the survey. The beluga whale also is unlikely to detect sounds at these frequencies. However, bowhead and gray whales have been known to move away from a seismic search area.
As part of the proposed authorization, the fisheries service proposes that BP Exploration observe several operating procedures designed to avoid potential injury to marine mammals. The fisheries services proposes that 1) biological observers onboard the seismic vessels monitor marine mammal presence in the vicinity of the seismic array. To avoid the potential for serious injury, the array would be powered down if pinnipeds are sighted within 500 feet or if cetaceans are sighted within 2,130 feet; 2) the airguns be brought to operating levels over a several minute period at the commencement of operations or after any period where the array is powered down; and 3) if marine mammals are observed within a safety zone designated to prevent injury to the animals, delaying start-up operations until all marine mammals are outside that distance.
In addition, BP Exploration is developing an agreement with Native American subsistence whalers to reduce any potential interference with their hunt as well as provide monitoring information to help resolve uncertainties about the effects of seismic exploration on the accessibility of bowheads to hunters.
Comments will be received through June 24, 1996, and should be addressed to Chief, Marine Mammal Division, Office of Protected Resources, National Marine Fisheries Service, 1315 East-West Highway, Silver Spring, MD 20910- 3225. Copies of the application and an environmental assessment may be obtained by contacting the above office.
###
Additional information can be found on the Internet.
National Marine Fisheries Service:
http://kingfish.ssp.nmfs.gov
Marine Mammals:
http://kingfish.ssp.nmfs.gov/tmcintyr/prot_res.html