SURVIVORS OF A pod of almost 100 whales that beached on the southwestern Australian coast have been euthanised after a second day of frantic but unsuccessful efforts to rescue them, authorities have said.

The pod of long-finned pilot whales stranded themselves on Tuesday on Cheynes Beach, east of the former whaling station of Albany in Western Australia state, south of the capital Perth.

Despite the efforts of 100 wildlife officers and 250 volunteers wearing wetsuits to protect against the southern hemisphere winter cold, 52 stranded whales died on the beach.

The remaining 45 were euthanised yesterday after efforts to lead them to deeper water failed.

The survivors continually returned to the shallows, the Western Australia Parks and Wildlife Service said in a statement last night.

“Sadly, the decision had to be made to euthanise the remaining whales to avoid prolonging their suffering,” the service said.

“It was a difficult decision for all involved, however the welfare of the whales had to take precedence.”

The service thanked the officials and volunteers who helped with the attempt to save the whales.

A storm lashed the beach with wind and rain yesterday afternoon and two volunteers were treated by paramedics for hypothermia, Australian Broadcasting Corp reported.

Peter Hartley, a manager of the Department of Biodiversity, Conservation and Attractions who oversaw the response, today described the decision to euthanise the survivors as “incredibly hard”.

“Probably one of the hardest decisions of my 34 years of wildlife management. Really, really difficult,” he told reporters in Albany.

“It was a considered and well thought out decision. And you know, we thank the support of the … veterinarians that assisted with the assessments and the advice that they gave me to make that decision.”

Wildlife experts speculated the beaching could be an indicator of stress or illness within the pod but said the reasons will likely remain a mystery.

Pilot whales are highly social animals and maintain complex familial relationships with their pods from birth.

Drone footage released by the state government showed the whales clustering and forming into a heart shape before stranding themselves on the beach.

Hartley said samples would be taken from the whale carcasses for analysis before they are buried at an inland location.

“We’re getting requests from around the world from scientists wanting the video footage of them all huddled together on the Tuesday,” he said.

“We’re going to be learning a lot about the behaviour. We’re also going to be learning a great deal about the genetics, the make up of that group. Were they related?”

The incident was reminiscent of one last September, when 200 pilot whales died after a pod stranded itself on the remote west coast of the island state of Tasmania, off Australia’s southeastern coast.

The following month, nearly 500 pilot whales died after stranding themselves on two remote beaches in New Zealand.