Volunteers working to save nearly 100 beached whales in Australia, but more than half have died.

Nearly 100 long-finned pilot whales stranded themselves on the beach by the city of Albany, on the southern tip of Western Australia, south of Perth, on Tuesday.

They were first spotted swimming on Tuesday morning near Cheynes Beach east of Albany. As the day progressed, the pod began moving closer to the beach, sparking the concern of conservation officers. By 4pm, a large stretch of the shoreline was covered in beached whales.

Reece Whitby, Western Australia’s environment minister, said it was particularly frustrating because it is unknown why the phenomenon occurs.

“What we’re seeing is utterly heartbreaking and distressing,” he told reporters. “It’s just a terrible, terrible tragedy to see these dead pilot whales on the beach.”

He said 52 whales had perished, and volunteers were doing what they could to try and save 45 still alive.

“People are committed to doing what they can to save as many whales as they can,” Whitby said.

Western Australia state’s Department of Biodiversity, Conservation and Attractions set up an overnight camp to monitor the whales.

Peter Hartley, a manager from the department, told the Australian Broadcasting Corp that the volunteers were trying to get the living whales back into the water and encourage them to swim away.

“We are optimistic that we will save as many as we can,” Hartley said.

The team helping the whales includes Perth Zoo veterinarians and marine fauna experts. They have been using specialised equipment, including vessels and slings.

Hundreds of volunteers also offered to help – so many that officials said they had enough registered volunteers and urged other members of the public to stay away from the beach.

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

Pilot whales are notorious for their strong social bonds, so when one whale gets into difficulty and strands, the rest usually follow, according to marine experts.

‘We just don’t know’

Wildlife experts said the whales’ unusual behaviour could indicate stress or illness within the pod. Pilot whales are highly social animals and often maintain close relationships with their pods throughout their lives.

Macquarie University wildlife scientist Vanessa Pirotta said the drone footage could suggest the whales had become disoriented, although she said the exact reasons for mass strandings remain unclear.

“The fact that they were in one area very huddled, and doing really interesting behaviours, and looking around at times, suggests that something else is going on that we just don’t know,” she said.

Pirotta said she thought it unlikely the whales were trying to avoid a predator.

“They often have a follow-the-leader type mentality, and that can very much be one of the reasons why we see stranding of not just one but many,” Pirotta added.

The incident is reminiscent of one in September, where some 200 pilot whales died after a pod stranded itself on the remote west coast 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.