Local officials in Hokota, some 60 miles northeast of Tokyo, said that rescue efforts had to be abandoned as darkness fell. Volunteers managed to save just three of the group before efforts were halted, according to AFP. Melon-headed whales are a member of the dolphin family which usually lives in the deep ocean, and it is not known why such a large group became stranded.

Around 150 Dolphins Thought To Have Died In Japan

Animals so weak they could not swim

Locals joined coastguard teams in trying to save the animals, but they became very weak over the course of the day. Volunteers, who struggled without the aid of heavy equipment, had to leave the beach as night fell due to dangerous conditions.

Some of the animals were taken back to the sea in slings, but the tide carried them back to shore soon after being released. According to officials, it was the first time that a pod of over 100 sea mammals has washed ashore in Japan.

The three surviving animals were taken 10 kilometers offshore in a coastguard vessel before being released. News footage showed weakened dolphins being pushed around by the waves in shallow waters.

Dolphins: Complicated Japanese relationship with cetaceans

Tadsu Yamadao, a researcher at Japan’s National Museum of Nature and Science, said that the dolphins may have got lost. “Sonar waves the dolphins emit might have been absorbed in the shoals, which could cause them to lose their sense of direction,” he said.

Melon-headed whales are also known as electra dolphins, and are fairly common in the waters off Japan. Around 50 animals from the same species beached themselves on a nearby beach in 2011.

The rescue effort flies in the face of worldwide perceptions of Japan’s relationship with cetaceans. Despite criticism, Japan continues to hunt minke and pilot whales off its coast, and also hunted in the Antarctic for many years, with the meat brought back for human consumption.

Japan insists that whaling is a tradition which should be allowed to continue, calling environmental campaigners “cultural imperialists.” A UN court ordered the end of the practice last year but Tokyo claims that it will restart the Antarctic expeditions.

Perhaps the most famous instance of cetacean slaughter in Japan was exposed by Oscar-winning documentary “The Cove,” which shows the annual slaughter of hundreds of dolphins in a bay in the south of the country.