The whales are stranded at Toby Inlet in Geographe Bay, the Western Australia department of biodiversity, conservation and attractions said. The area is near the town of Dunsborough in the southwestern region popular with tourists, and about 236km south of state capital Perth.

“We understand there are four pods of up to 160 pilot whales in total spread across about 500m. Unfortunately, 26 whales that stranded on the beach have died,” a department spokesman said in a statement.

“A team of experienced staff including wildlife officers, marine scientists, veterinarians are on site or on their way.”

Based on previous strandings, “these events usually result in the beached animals having to be euthanised as the most humane outcome,” the spokesman said.

In July last year, more than 50 pilot whales died after stranding on a remote Western Australia beach.

Pilot whales are known for their tight-knit social bonds, so when one gets into difficulty and strands, the rest often follow, according to the University of Western Australia.