MIAMI – Rescue teams are on standby in case more dolphins are spotted in shallow waters off the western edge of Florida's Everglades.
According to the National Oceanic and Atmospheric Administration's fisheries service, 81 false killer whales had died or been euthanized by Monday afternoon.
The Coast Guard first spotted the large, black dolphins Saturday in the Gulf of Mexico off southwest Florida. NOAA officials say over a dozen more dolphins had been spotted over the weekend off Hog Key but haven't been found.
Necropsies will be performed on the dead dolphins. NOAA officials said Tuesday that it could take months for biologists to determine what caused so many of the animals to become stranded.
According to NOAA information , false killer whales usually swim in large groups. The animals also are known to strand in large groups.