At least 380 whales dead in Australia mass stranding

At least 380 whales have died in a mass stranding in southern Australia, officials said Wednesday, as hopes faded of saving more than a few dozen of those creatures still trapped.

Nearly the entire pod of 460 long-finned pilot whales stuck in Macquarie Harbour -- on the rugged and sparsely populated west coast of Tasmania -- has now perished.

"We can confirm that 380 whales are dead," Tasmania's Parks and Wildlife Service manager Nic Deka said, describing the three-day rescue effort as emotionally and physically taxing.

"There's around 30 left still alive, but the good news is that we have saved 50," he said.

It is believed to be the largest mass stranding ever recorded in Australia, and is among the largest anywhere in the world.

The first of the giant mammals were discovered floundering on Monday, sparking a major effort to free them from sandbars and beaches only accessible by boat.

A rescue crew of 60 conservationists, skilled volunteers and local fish farm workers have spent days wading in icy water trying to release the whales -- which can grow up to six metres (20 feet) long and weigh a tonne each.

The crews have focused efforts on a group of 30 partially submerged whales, using boats fitted with special slings to guide them back to the open ocean.

"They're focused on the job -- it's demanding work, some of them are up to their chest in cold water so we're trying to rotate the crews," Deka said.

"Its very draining physically. It's also draining emotionally."

Nearby, rescuers decked in florescent uniforms tried to cloak fully beached whales in wet sheets to keep them alive, while other members of the once close-knit pod lay dead.

"As time goes on (the whales) do become more fatigued so their chances of survival reduces," Deka said. "But we'll keep working as long as there's live animals at the site."

"Increasingly our focus is shifting to what to do with the retrieval and disposal of the carcases."

The whales have been found stranded across an area 10 kilometres (six miles) long, and the search area has been expanded to see if more of the mammals are stuck nearby.

Some of the whales rescued Tuesday re-stranded overnight, in line with predictions by whale behaviour experts, who say the highly social creatures would try to return to be with family and friends.

But Deka remained upbeat about the immediate prospects for those that made it to the ocean.

"The good news is the majority of whales that were rescued are still out in deep water and swimming," he told reporters in the nearby town of Strahan.

"They haven't stranded. So we've been more successful than not."

The causes of mass strandings remain unknown -- even to scientists who have been studying the phenomenon for decades.

Some researchers have suggested the pilot whales may have gone off track after feeding close to the shoreline or by following one or two whales that strayed.

Tasmanian environment department marine biologist Kris Carlyon said it was a "natural event" with strandings of the species occurring regularly throughout history in both southern Australian and neighbouring New Zealand.

"We do step in and respond in these situations, but as far as being able to prevent these occurring in the future, there's really little that we can do," he said.

Carlyon said animal welfare issues were a major reason authorities and conservationists intervened in mass strandings, along with public expectations and the opportunity to learn more about a species.

It would have been a "hugely stressful" experience for the whales that were freed, he said, but past events showed they were likely to thrive in the wild.

"We have shown fairly conclusively that animals will regroup, they will reform those social bonds, and they will -- at least in the short- to medium-term for the duration that they've been tracked -- demonstrate normal and natural behaviour," Carlyon said.