Navy to study possible link between beached whales and sonar

Seven whales that beached themselves in the Bahamas might have been affected by powerful sonar from Navy ships

July 28, 2000
Web posted at: 3:25 PM EDT (1925 GMT)

(CNN) -- Important clues have surfaced that may help prove a suspected link between beached whales and powerful sonar equipment used by the U.S. Navy and other nations around the world.

Scientists discovered the clues earlier this year in March, when seven whales were found dead on a Bahamas beach, near the time and location of a U.S. Navy sonar operation.

"We did have an operational exercise going on using ships with operational sonars," said Robert Pirie, assistant secretary, U.S. Navy. "...and that was closely correlated with the ... strandings and that's the source of our concern."

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"The whale beachings came about the same day as a naval operation," said Roger Gentry of the National Marine Fisheries Service.

The seven dead whales were found to have inner ear damage, which scientists said might have ruined their sense of direction and ability to navigate.

Whales with inner ear damage can become disoriented and mistakenly swim too close to shore, beaching themselves and eventually dying.

Because multiple inner ear damage among beached whales is very rare, officials said creatures might have been injured by the Navy's powerful sonar technology.

"The kind of acoustic event that would cause the trauma we saw would be fairly intense," Gentry said.

Although scientists have long suspected that whale beachings were linked to Navy activities, the March beaching has provided some of the strongest evidence to date reinforcing that suspicion.

In previous beachings where sonar was the suspected cause, no whale carcasses were recovered for study.

"What's different about the present beaching is that we do have good biological material," Gentry said.

Researchers studying the beached whale carcasses discovered inner ear damage, possibly caused by sonar

The Navy has not accepted responsibility for the Bahamas beaching, but it has agreed to release technical data about the underwater region during the sonar operation.

The National Marine Fisheries Service and the U.S. Navy plan to release a final report on the whale beaching by summer, 2001.

The report may provide more insight into how marine mammals use underwater sounds and possibly may prevent deadly whale beachings in the future.

CNN Correspondent David George contributed to this report.

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More info on beaked whales from Texas A & M University
U.S. Navy
NOAA

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