Everglades National Park, Florida (CNN) -- Dozens of short-finned pilot whales moved Thursday to slightly deeper water off Florida's Everglades National Park, raising hope a day after the mass stranding saw 11 of the mammals die.
Wildlife officials were cautiously optimistic that the 35 remaining whales would make it into deep open waters but warned that the mammals still had miles to go, said Blair Mase, a marine mammal scientist with the National Oceanic and Atmospheric Administration.
Calling it a "very fluid situation," scientists continue to monitor the whales, Mase said.
The whales were in about 18 feet of water and were moving offshore, she said.
Wildlife officials are unsure how long the pod of whales has been stranded or why. Fishermen spotted the pod of 51 whales, several of which had beached themselves, on Tuesday night in a remote area accessible only by boat off the west coast of the Everglades, park spokeswoman Linda Friar said.
Eleven of the whales have died, including four found in "poor condition" and euthanized, and five more went missing overnight, according to Mase.
The Coast Guard conducted an aerial search for the missing five but have been unable to locate them. It's possible the whales have died, Mase said.
The whales are very communal and stay together, and the fact that the remaining pod moved away from shore overnight could help their chances of survival.
"We were surprised they were not in the area and that they had moved so far north and were moving in an off shore direction," Mase said.
Rescuers used about 15 boats to herd the whales toward more open waters in the Gulf of Mexico.
On Wednesday, with the whales in waters of 2 to 4 feet, herding efforts failed.
Mass strandings by pilot whales are not altogether uncommon in Florida. In 2012, nearly two dozen pilot whales stranded and beached themselves. In 2011, 23 pilot whales stranded and beached themselves.
CNN's John Zarrella reported this story from Everglades National Park; Chelsea J. Carter reported and wrote from Atlanta