People walk near whales stranded on a beach at Toby's Inlet, Dunsborough, Australia, on Thursday. Reuters

Marine biologists raced Thursday to save more than 100 pilot whales after a mass stranding on an Australian beach, with officials fearing many will have to be euthanised.

Western Australia's Parks and Wildlife Service said 26 of the beached pilot whales had already died.

As many as 160 pilot whales became stranded Thursday morning at Toby's Inlet, officials said, located about three hours' drive south of state capital Perth.

"A team of experienced staff including wildlife officers, marine scientists, veterinarians are on site or on their way," the Parks and Wildlife Service said in a statement.

Wildlife officers will try to guide some of the pilot whales away from the beach and into deeper water.

But the service said that "these events usually result in the beached animals having to be euthanised as the most humane outcome".

"We always hope for the best outcome," the wildlife service added.

Mass strandings of pilot whales are not uncommon in Australia and New Zealand.

This handout photo shows pilot whales stranded at Toby's Inlet near Dunsborough in Western Australia. AFP

Around 500 pilot whales died when they beached on New Zealand's remote Chatham Islands in 2022.

Scientists do not fully understand why mass strandings occur, but some researchers think pods go off track after feeding too close to shore.

Pilot whales — which can grow to more than six metres (20 feet) long -- are highly sociable, so they may follow pod-mates who stray into danger.

Agence France-Presse