By Sid Perkins
Field tests in the Gulf of Mexico suggest that sperm whales there don’t swim away from boats conducting seismic surveys of the seafloor. However, the surveys’ noise—typically generated during the hunt for oil and natural gas deposits—may be having subtle effects on the whales’ feeding behavior.
Scientists use a device called an air gun to probe the seafloor. A burst of compressed air at the ocean’s surface creates intense pressure pulses that travel through the water. The intensity and timing of the echoes from the ocean bottom provide information about buried geological structures. Biologists have been concerned that such pulses may damage a whale’s hearing or mask the clicks that whales make to home in on food, says Patrick J. Miller, a marine biologist at the University of St. Andrews in Scotland.