Tim Cuff/Associated Press

Volunteers in New Zealand are struggling to keep pace with hundreds of pilot whales that have accidentally beached themselves and need assistance returning to the sea. A group of more than 400 whales were first found on the beach Friday. About 300 of them died before they could be rescued, but roughly 100 members of the pod were refloated.

Saturday morning, however, about 240 additional pilot whales were beached in the same three-mile stretch. They are mostly not the same as the 100 refloated whales, which were tagged as they were released, but 20 of the 100 did return and had to be euthanized. Fresh rescue efforts remain underway.

The area where the whales are turning up is called Farewell Spit, a long peninsula that forms the boundary of one side of Golden Bay on New Zealand's South Island, where Christchurch is located. "It's a very difficult place if you get lost in there and you are a whale," said Herb Christophers of New Zealand's conservation department. The whales' echolocation ability is inhibited in shallower waters, and Farewell Spit has played host to mass whale beachings before.