No Sonar Link Found in Dolphin Deaths

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Virginian-Pilot | March 04, 2008

From a public relations perspective, the strandings of four marine mammals here last week couldn't have come at a worse time for the Navy.

The service is hosting a public hearing in Virginia Beach today on the effects of its sonar training on marine mammals. Some scientists insist sonar harms dolphins, whales and the like.

But those investigating the recent strandings say they have found no link to Navy sonar.

This weekend, three dolphins were found on the shores of the Back Bay National Wildlife Refuge.

Days before, a porpoise washed ashore on the Cape Hatteras National Seashore in North Carolina. It was airlifted from Suffolk to a marine rehabilitation center in New York, where it died. The dolphins had to be euthanized because they were too weak to be saved.

U.S. Fleet Forces Command spokesman Jim Brantley said the Navy hasn't conducted sonar tests within 200 nautical miles of the Virginia coast for more than a week.

Virginia Aquarium & Marine Science Center spokeswoman Joan Barns said a necropsy on the first of the three dolphins established no cause for the stranding - including the telltale physical effects scientists say are caused by sonar.

Marine biologists say sonar can harm or kill marine mammals by causing hemorrhages around the eardrums. They say the injuries cause irregular diving patterns, which can induce something akin to the decompression sickness - "the bends" - that divers experience.

Barns said the necropsy revealed no such trauma, though tests won't be conclusive until lab results are returned.

She said park rangers are scouring the Virginia coast for further strandings; they have found nothing so far.

About 100 marine mammals wash ashore on the Virginia coast each year, Barns said, with only about 10 percent alive when found. It's rare that a marine mammal washed ashore survives.

Three or more mammals stranded constitute a "mass stranding," a cause for alarm in itself.

"Whenever you have a mass stranding, it's possible there could be more further up the coast, or below," Barns said.

The Navy generally denies its anti-submarine sonar system causes strandings. But links between sonar and strandings have been established, including in 2000, when 17 whales were beached in the Bahamas. In 2005, more than 30 whales died on Outer Banks beaches following a sonar exercise.

In 2002, 14 beached whales in the Canary Islands were linked to sonar tests conducted more than a week before - about 150 miles away, according to the Natural Resources Defense Council .

"You could have an animal affected on day one and see no physical evidence for some time thereafter," Natural Resources Defense Council policy analyst Michael Jasny said in a telephone interview from Santa Monica, Calif. "People think of noise literally driving animals onto the beach, that it's a pure panic response, but we see evidence of another pathway of harm."

The Navy has proposed four locations for a $100 million, 625- square-mile sonar training facility, including locations off Wallops Island and Cape Fear, N.C.

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