20 December 2001
December 20, 2001
SAN JUAN, Puerto Rico (AP) -- U.S. Navy sonar tests likely caused 16 whales to beach themselves in the Bahamas last year, according to a federal study released Thursday.
The whales swam on shore on the islands of Abaco, Grand Bahamas and North Eleuthera on March 15 and 16 as Navy ships were testing sonar in the area. Six whales died, including five Cuvier beaked whales and a Blainville's beaked whale. The others were pushed back into the sea.
Earlier, the Navy had questioned a link between its sonar tests and whale beachings.
But the joint study by the Navy and U.S. National Marine Fisheries Service was based on examinations of the corpses of five of the six dead whales.
Each of the whales had hemorrhaged near its ears, said the 66-page report. It said the wounds would not be fatal but could have led the animals to become disoriented and swim on shore.
``The investigation team concludes that tactical mid-range frequency sonars aboard U.S. Navy ships that were in use during the sonar exercise in question were the most plausible source of this acoustic or impulse trauma,'' the report said.
The ships from the U.S. Navy Atlantic Fleet had been conducting intensive tests of multiple anti-submarine sonar units in the Providence Channel separating the islands, the report said. The unusual narrowness of the channel aggravated the problem for the whales.
Previously, scientists' efforts to link whale beachings to sonar have been frustrated because corpses were too decomposed to study. They included the 1996 beachings of 12 Cuvier beaked whales in the Ionian Sea between Greece and Italy during NATO anti-submarine exercises.
In the Bahamas, many of the whales were beached in front of the Abaco Island home of Ken Balcomb, research director of the Washington-based Center for Whale Research.
He made sure the corpses were well preserved for study.
In the report, the Navy said it will work to decrease the chance of causing whales to beach themselves as long as national security is not compromised.