Was sub cause of dolphins' beaching?
Both the Navy and marine experts are investigating whether sonar is to blame.
Published March 6, 2005
KEY WEST - The Navy and marine wildlife experts are investigating whether a submarine used sonar before dozens of dolphins beached themselves near Marathon.
More than 20 rough-toothed dolphins have died since Wednesday's mass grounding of about 68 dolphins, Florida Keys National Marine Sanctuary spokeswoman Cheva Heck said Saturday.
The beachings came a day after the USS Philadelphia conducted exercises off Key West, about 45 miles from Marathon.
Navy officials refused to say whether the submarine used its sonar during a training exercise with Navy SEALs.
But naval ships emitting pulses of sound have been blamed for at least one mass beaching. Scientists surmise that sonar may disorient or scare marine mammals, causing them to surface too quickly and creating the equivalent of what divers know as the bends - when nitrogen is formed in tissue by sudden decompression, leading to hemorrhaging.
"This is absolutely high priority," said Lt. Cmdr. Jensin Sommer, a spokeswoman for Naval Submarine Forces, which is based in Norfolk, Va. "We are looking into this. We want to be good stewards of the environment, and any time there are strandings of marine mammals we look into the operations and locations of any ships that might have been operating in that area."
The National Marine Fisheries Service is conducting necropsies on the dead dolphins, looking for signs of acoustic trauma.
"We certainly will do a thorough exam on as many as possible before we go to the Navy," said Teri Rowles, coordinator of the service's marine mammal health and stranding response program. "We have not, in this particular case, gone to them and said, "What were you doing?' and asking them to do (a sound impact study)."