Key West, Fla. – When more than 70 dolphins beached themselves near here in March, leaving well over half of them dead, there was one immediate suspect: a U.S. Navy submarine conducting exercises off the Florida Keys in the days before the marine mammals came to shore.
Nearly two months later, National Oceanic and Atmospheric Administration investigators are still conducting tests that may show whether submarine sonar was responsible.
A few biologists who necropsied some of the animals observed heart and lung problems in the dead dolphins that may not be indicative of harm from sonar.
“We haven’t ruled anything out. We are in the process of compiling results,” said Laura Engleby, a NOAA Fisheries biologist involved in the stranding response.
Sonar – short for “sound navigation and ranging” – determines distance by transmitting a sound pulse into the water and measuring how long it takes the sound waves to bounce off objects and return.
Marine mammals also have their own highly developed “sonar” systems of echo-location “clicks.”
