Sub linked to dolphins' death

The US government has launched an investigation into whether the mass beaching of dolphins in south Florida this past week was caused by naval exercises involving a sonar-equipped submarine, officials said late on Saturday.

More than 60 disoriented dolphins swam into ankle-deep waters off the Florida Keys near the town of Marathon last Wednesday, prompting a massive rescue operation involving wildlife officials and dozens of volunteers.

Some mammals have been successfully led back to deep water. But about two dozen others have already died or have been euthanized to stop their suffering. More dolphins are being taken care of by biologists and park rangers.

Nobody knows exactly at this point what caused the dolphins to beach.

But US Navy and environmental officials said they were looking into the possibility that top-secret exercises involving the USS Philadelphia, a Los-Angeles-class attack submarine, had anything to do with the tragic events.

"The Navy takes this very seriously and is, of course, interested in the outcome" of the investigation, senior chief Gregg Snaza, a spokesman for the US Fleet Force Command, told AFP in a telephone interview from Norfolk, Virginia.

Navy researching the incident
He said the National Oceanic and Atmospheric Administration was leading the probe, but the military was "concerned" about the incident and was providing full co-operation as they wait for the results of post-mortems.

The Philadelphia, which is reported to have been about 65km off the Florida Keys on Wednesday, had on board a group of SEAL commandos, one of the elite US special operations teams trained to stealthily penetrate enemy territory, often from submerged vessels.

Snaza declined to describe the nature of the mission, but said it was "an interoperability exercise" designed to fine-tune co-operation between various components of the Navy.

"They were working with the SEALs in support of special ops forces," he said of the Groton, Connecticut-based submarine crew. "That is one of the many missions our attack submarines are capable of doing."

The spokesperson could not confirm or deny whether sonar was used by the Philadelphia, saying, "The Navy is researching that."