Dozens of Dolphins Have Washed Up on Japan’s Beaches. No One Knows Why.

Eight dolphins were found washed up on beaches in the Greater Tokyo Area on Tuesday morning, according to local news reports. 

The mammals, identified as melon-headed whales, looked like they were struggling to breathe, said Mibu Saito, a local official who visited the site nearby Isumi and Ichinomiya in Chiba Prefecture. 

“I felt sorry for all those weak dolphins that had washed ashore and we still don’t know why they were stranded there,” Saito told VICE World News. 

Of the eight found, four were dead, while the rest were returned to the ocean. A day earlier, 33 dolphins were also found beached just a few hundred meters away. Passersby and surfers tried to carry or roll the dolphins towards the ocean, but two died, Saito said. 

News of dolphins washing up on Japan’s beaches follows similar reports of whale and dolphin deaths around the world. 

Since early December, 23 dead whales have washed ashore along the U.S.’ east coast. Scientists in France have also observed 910 dead dolphins washed up along the country’s Atlantic coast since the start of winter, prompting the country’s highest court to mandate that the government curb fishing in certain areas. 

In South Korea, a whale carcass was found in March. Authorities said there were no signs of illegal capture of the mammal, identified as a Bryde's whale, an endangered species. 

Researchers are still trying to confirm why so many whales and dolphins are washing up on beaches.

In the U.S., the National Oceanic and Atmospheric Administration identified vessel strikes, entanglement in fishing equipment and changing water temperatures as some of the biggest threats to humpback whales, a species frequently found dead along the country’s east coast. 

In Japan, the National Museum of Nature and Science plans to conduct autopsies on the dolphins to analyze what could’ve caused their deaths, Saito said. 

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