Dozens of pilot whales stranded in Everglades National Park in Florida

Rangers and wildlife workers are battling to save dozens of pilot whales that are beached or stranded in shallow waters in the Everglades National Park in southwest Florida.

At least 10 of the 51 short-finned pilot whales have died since the pod was first spotted on Tuesday afternoon. Rescuers don’t know how long the whales had been there. 

A glimmer of hope did emerge Thursday afternoon for 20 of the whales, which were spotted swimming in live-saving deeper water, according to The Associated Press.

The two pods were about 11 miles offshore.

Wildlife officials prepared to use sound and other herding techniques to try to get the whales out of the Everglades and back into the Gulf of Mexico.

The whales are stranded in a remote part of the national park, which has complicated rescue efforts. 

The area is covered with sand bars and sand flats, and attempts to herd the whales to deeper waters have so far failed.

The outlook for their survival “does not look good,” Blair Mase, a marine mammal scientist with the National Oceanic and Atmospheric Administration, told CNN.

"We want to set the expectations low" that the remaining stranded whales can be saved, Mase said.

Such mass strandings of pilot whales in Florida are not uncommon.