MIAMI: More than 80 dolphins known as false killer whales have died off the southwest coast of Florida after getting stranded in shallow waters, US officials said.

A pod of 95 of the dolphins, which are black in colour and look like killer whales without white markings, became stranded in the Gulf Coast off Everglades National Park, the park said on Twitter.

Photos on social media showed dozens of these dolphins, some grouped in clusters of four or five, just a few feet from a sandy beach lined with trees.

“Sadly, 81 have already been confirmed dead,” Everglades National Park said Monday, adding that marine mammal rescue operations were being carried out.

The dolphins had become “deeply embedded in some of the mangroves making response efforts extremely difficult,” Blair Mase, a stranding coordinator with NOAA’s fisheries service, said in the Miami Herald newspaper.

The National Oceanic and Atmospheric Administration said that of the remaining dolphins, one had been seen alive and 13 others were unaccounted for.

While 72 had died on their own, rescuers put down nine that were too sick to survive, Mase said.

The stranded dolphins include adults, juveniles and calves, and were first spotted Saturday in an area called Hog Key, part of a string of islands, according to the Herald.

False killer whales can be found in large groups of more than one hundred in warm waters across the globe. They have long, slender bodies and narrow, tapered heads with rounded snouts.

They are much smaller and less aggressive than their distant relative, the Orca, or killer whale. Like Orcas, scientists classify them as dolphins rather than whales.

The phenomenon of strandings and the causes remain the subject of scientific debate.

The National Park Service has closed the area surrounding the dolphins to flyovers and boats.

Published in Dawn January 18th, 2017