Large pod of false killer whales strands in mainland Monroe

Rescue efforts continue Monday in the largest stranding of false killer whales in recorded Florida history, taking place at a remote mangrove beach in mainland Monroe County.

Estimates say 95 of the marine mammals — actually a large dolphin frequently mistaken for orcas — swam into Gulf of Mexico shallows near the Highland Beach area, inside western Everglades National Park.

As of midday Monday, 81 of the false killer whales had died. Nine were “humanely euthanized” and 72 others died. Search and rescue efforts continue for other false killer whales that disappeared during the night.

“There are all age classes, males and females ranging from adults to juveniles and calves,” Blair Mase, NOAA Fisheries Southeast Marine Mammal Stranding Network coordinator, said Monday.

The first reports came in not long before nightfall Saturday with the full response mobilizing Sunday.

The site, about 54 miles north of the Florida Keys city of Marathon by boat, creates major problems for responders, Mase said. There are no roads and responders make about an hour’s boat trip to reach the Gulf of Mexico scene .

The dolphins (Pseudorca crassidens) were “scattered along the beach and deeply embedded into the mangrove shoreline, making response extremely difficult,” she said.

Rescue groups, including members of the Dolphins Plus Oceanside Marine Mammal Responders unit from Key Largo, “are dealing with sharks and things like that,” Mase said. Even telephone communication to the area, south of Chokoloskee, is spotty.

Male false killer whales can reach 20 feet, females growing to about 15 feet. They can weigh 1,500 pounds.

Only two other strandings of false killer whales have been recorded in Florida. The first was in 1986 when 28 false killer whales beached near Key West. Three years later, 40 false killer whales beached off Cedar Key.

Biologists are examining the dead dolphins in an effort to determine the cause of the stranding, Mase said.

Agencies taking part in the rescue effort include the Florida Fish and Wildlife Conservation Commission, Mote Marine Laboratory, Harbor Branch Oceanographic Institute, Marine Animal Rescue Society, Chicago Zoological Society, National Park Service, NOAA Fisheries, Rookery Bay National Estuarine Research, the University of Florida, U.S. Coast Guard and U.S. Geological Survey.

This story was originally published January 16, 2017 at 2:48 PM with the headline "Large pod of false killer whales strands in mainland Monroe."