In the Gulf of Mexico, the great sperm whales of Moby Dick fame, (Physeter macrocephalus), are being silently tracked. Navy's former "silent runners" - quiet ships originally designed to trail enemy submarines - follow the whales to areas off the Mississippi Delta rich in food sources, but also rich in potentially hazardous underwater noise.
Concerned that the increasing levels of manmade noise can hurt this endangered species as well as others, the Office of Naval Research (ONR) cooperates with a team of agencies interested in knowing exactly how the sperm whale is being affected behaviorally by the noise of off-shore drilling and seismic surveys. Lead by the Department of the Interior's Minerals Management Service, the ecology of the entire Gulf is being studied to assess the noise problem.
"This is logistically challenging," says Dr. Bob Gisiner, ONR's marine mammal expert, "But it's a highly effective way to determine if, and at what scale large wide-ranging species like whales might be affected by manmade sounds from activities like geophysical exploration. ONR is helping with the acoustics expertise."
Last summer several whales were tagged to assess their responses to manmade noise and to record the sounds they made themselves while diving. Tagging teams use short duration suction cup mountings to attach acoustic tags on the whales. The tags can collect several gigabytes of sound recordings and movement data. After a few hours the tags are retrieved, the data are downloaded into a computer, and within minutes the tag is ready to 'go on board' another whale. The tagging involves a coordination of spotters on the bridge of the ship, acoustics and recording teams in the ship's computer room, and the actual tagging teams aboard a specially built close-approach vessel.
The Gulf sperm whale study, begun in summer 2000, will be repeated in summer 2001. This study provides the concurrent, integrated oceanographic, climactic, and biological data needed for graphical modeling and environmental risk assessment systems like Global Information Systems (GIS) and ONR's ESME (Effects of Sound on the Marine Environment) project.
Materials provided by Office Of Naval Research. Note: Content may be edited for style and length.
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