DARWIN, Australia – They may have taken a wrong turn, chased their prey into shallow waters or blindly followed a dying matriarch who intended to beach herself. But the pilot whales, more than 450 of them, somehow ended up stranded on a remote beach in Tasmania.

More than half of them are likely already dead. Now, scientists are racing to save the others.

“It is quite confronting,” Kris Carlyon, a marine biologist with the Tasmanian government, said Tuesday. “This is such a tricky event, a complex event, that any whale we save we consider a real win. We’re focusing on having as many survivors as we can.”

Already by Tuesday, a day after the pod was first seen, the team of scientists, government workers and police officers had saved at least 25 whales by dragging them off sandbars and away from the shore, guiding them back out to sea.

On Wednesday morning, a further 200 whales were found 4 to 6 miles deeper into the harbor. Most of them were believed to be dead.

Mass strandings off Tasmania, an Australian state, are not uncommon, but the recent beaching is among the worst in the state’s history and the first involving more than 50 pilot whales since 2009.

Once beached, whales find it difficult to make their way back to the safety of the open ocean. The creatures can quickly become exhausted and stressed, and eventually drown.

Carlyon, who has spent more than a decade studying such strandings, is leading a team of more than 60 rescue workers. The team places a sling under each animal and drags it by boat to the opening of the harbor, which is very narrow. The whales can measure up to 25 feet long and can weigh more than 3 tons. Complicating the effort are the frigid water temperatures.