About 50 whales were found dead Wednesday after they beached for a second time on a Chiba Prefecture beach, despite an earlier attempt to redirect them to the sea, an official said Wednesday.

The dead whales were among a pod of about 70 melon-headed whales that had first beached themselves in Ichinomiya, Chiba Prefecture, early Tuesday morning, said Ichinomiya town official Mieko Ishii.

Surfers and local residents had helped return the whales to sea, but by Wednesday morning the pod had run itself back up on the shore, Ishii said.

She said about 50 whales were found dead, while the remaining 20 -- each measuring about 2 meters long -- were transported to a relatively calm fishing port and would be released into the sea at a later date.

Experts would examine some of the dead mammals to determine a cause of the death, while the remaining will be buried in the town, Ishii said.

The whales resemble dolphins and usually inhabit only deep water. It was not immediately known why such a large number of the whales washed up at one time, Ishii said.