The BBC reported that the 240 more pilot whales have been stranded on a remote beach in New Zealand. On Saturday, volunteers refloated about 100 of the 400 pilot whales that beached on Thursday.

The whale stranding, at Farewell Spit at the top of the South Island, is one of the worst ever in New Zealand. It is not understood why whales beach. One theory is that they have been attacked by sharks and driven on to land, after bite marks were found on one of the dead whales.

An expert from New Zealand’s department of conservation Herb Christophers said that the whales were trying to swim around South Island, but if their navigation had gone wrong they ended up on the beach.