EVERGLADES NATIONAL PARK, Fla. — Wildlife workers in boats struggled unsuccessfully Wednesday to coax nearly four dozen pilot whales out of dangerous shallow waters in Florida’s Everglades National Park, hoping to spare them the fate of 10 others that already had died.

The workers suspended their efforts after dark, but planned to return Thursday morning to try again, said Kim Amendola, spokeswoman for the National Oceanic and Atmospheric Administration, which is taking part in the effort.

Six of the whales were found dead, and four of the whales had to be euthanized Wednesday, said Blair Mase, coordinator for NOAA’s marine mammal stranding network. At least three could be seen on the beach, out of the water.

The whales are stranded in a remote area near Highland Beach, the western boundary of Everglades National Park and about 20 miles east of where they normally live. It takes more than an hour to reach the spot from the nearest boat ramp and there is no cellphone service, complicating rescue efforts.

“We want to set the expectation low, because the challenges are very, very difficult,” Mase said.

Park spokeswoman Linda Friar said rescuers were trying to surround the whales, which were in roughly 3 feet of salt water about 75 feet from shore, and herd them back to sea.

“They are not cooperating,” Friar said.

Workers also tried to nudge the whales out to sea earlier in the day with no success.