Hundreds of volunteers gathered at the northern tip of New Zealand’s Golden Bay early Friday morning after a government conservation worker discovered at least 416 pilot whales washed up on Farewell Spit beach ― one of the country’s largest whale strandings on record.

A team of more than 500 people managed to re-float up to 140 whales during high tide, but many swam in the wrong direction. Only 50 made it out into the bay without stranding themselves again. At least 250 died on the beach, according to a situation report from New Zealand’s Department of Conservation.

Farewell Spit is a curved, narrow sand landform on the northwestern coast of the South Island of New Zealand: Experts have described it as a “whale trap.” Nearly 200 pilot whales beached themselves in the area two years ago, and many died.

The latest rescue mission is ongoing, but DoC operations manager Andrew Lamason told local media that hope is “slowly slipping away.” Volunteers, DoC workers and members of marine mammal charity Project Jonah will attempt to re-float the remaining whales again during high tide on Saturday.

Barry Coates, a Green Party member of parliament, was at the scene of the rescue mission on Friday, and stressed the urgent need for increased DoC funding to research why this continues to happen.

“We need to change our policy and make sure we protect these magnificent mammals and these marine sanctuaries,” he said from the beach. “This is such a tragic situation.”

The photos below show volunteers rapidly working to save the surviving whales at Farewell Spit.

Anthony Phelps/Reuters

Anthony Phelps/Reuters

Anthony Phelps/Reuters

Anthony Phelps/Reuters

Anthony Phelps/Reuters

Anthony Phelps/Reuters

Anthony Phelps/Reuters

Anthony Phelps/Reuters

Anthony Phelps/Reuters

Anthony Phelps/Reuters