By Jane Sutton
MIAMI (Reuters) - Some of the pilot whales that were stranded in the Florida Everglades swam out into deeper water on Thursday while rescuers tried to chase the rest out to sea by banging on pipes and revving their boat engines.
Wildlife workers had hoped the cacophony would encourage the whales to leave the shallow water where 51 short-finned pilot whales beached in a remote part of Everglades National Park earlier this week.
Ten have died, the National Oceanic and Atmospheric Administration, or NOAA said.
On Thursday morning, Coast Guard helicopter crews spotted 15 to 20 of the survivors well north of the location where they were spotted a day earlier. By midafternoon on Thursday, they were in deeper water several miles from shore, NOAA said.
Biologists cautioned that beached pilot whales often re-beach and that survival rates in mass strandings were very low.
"Hard for them to get back to home range," NOAA said via Twitter.
Biologists were collecting samples from some of the carcasses in hopes of learning how they died.
About three dozen would-be rescuers from NOAA, the National Park Service, the Florida Fish and Wildlife Conservation Commission and local police set out in boats to join the rescue effort, while the Coast Guard tracked them from the air.
A Coast Guard cutter crew was also enforcing a safety zone to protect the whales and keep sightseers away.
"A lot of people may have good intentions of helping them and do more harm than good," Coast Guard Chief Petty Officer Ryan Doss said.
Pilot whales live in tightly cohesive groups and typically will not leave ailing or dead members behind. They are a deep-water species that forages on squid, octopus and fish and cannot live long in shallow water.
(Reporting by Jane Sutton; Editing by Bernadette Baum and Andre Grenon)