A fisherman came across about 150 carcasses of short-finned pilot whales on Friday morning and reported the situation to local authorities.
“When leaving the anchorage, we have seen four or five whales. I think there is more to the beaches, ”said fisherman Graham Pateman, who alerted authorities, to Australian television channel ABC.
Fears that dead whales may attract sharks prompted officials to close several beaches in the Hamelin Bay area of Australia's extreme southwest, about 196 miles south of Perth.
"It is possible that dead and dying animals act as an attractant, which could lead to sharks approaching the shoreline along this stretch of coast," the alert said.
Only 15 of the roughly 150 beached whales are still alive, authorities said.
The Incident Controller for the Department of Biodiversity, Conservation and Attractions, Jeremy Chick, said the priority was the safety of the surviving whales, as well as the 25 or so animals that are still found in deeper waters near the coast.
"The strength of the animals and windy and possibly wet weather conditions will affect when and where we try to get them out to sea," he told ABC. "The main objectives are to ensure the safety of staff and volunteers, as well as the best chance of survival for the whales."
Adult short-finned pilot whales are approximately 16.4 feet long and weigh up to three tons. They are found in most of the world's waters and generally travel in groups of less than 100.
Authorities said they will continue to sweep the surrounding beaches by air and sea on Saturday. Rescue efforts were hampered by dead whales in the water, rocky terrain, and rough seas.
The corpses were removed from the beach and authorities took DNA samples in an attempt to gather clues as to why the whales fell.
In 2009, more than 80 whales and dolphins died on a beach in Hamelin Bay.
The largest mass of whale strandings in Western Australia occurred in 1996 at Dunsborough. That year, 320 long-finned pilot whales went into hiding.