TOKYO -- About 150 dolphins beached themselves and became stranded on Japan's northeastern coast, but frantic rescue efforts Friday saved just a few of them.

Mostly melon-headed whales or blackfish, the dolphins were found alive but were extremely weak and later died.

Television footage showed dozens of people carrying buckets and pouring sea water over the dolphins, or even covering them with bath towels, to keep them from drying up. The dolphins were wobbling and moving their fins as rescuers gently rubbed them.

They dolphins between 2 to 3 metres long were scratched badly, possibly from moving in the shallow coastal waters and on dry land.

The stranding occurred along about 10 kilometres of beach in Hokota, northeast of Tokyo.

The coast guard and police patrol boats transported three of the dolphins in good health offshore and released them in the water. Nearly all of the others were thought to be hopeless. Those that die were to be buried.

Tadasu Yamada, a cetacean expert at the National Museum of Nature and Science, told Japan's NHK public television that the dolphins may have had a physiological or psychological problem and faced an unknown threat and panicked, before becoming stranded.

Smaller beachings have occurred around Japanese coasts, including some 50 dolphins on a nearby beach in 2011.