Tonnes of dead sardines and mackerel were recently discovered on Hamamachi beach in Hakodate, northern Japan, local media reported.
Local fishermen have been working on collecting and disposing of dead fish, and 85 tonnes had been collected as of December 14.
Tens of thousands of sardines and mackerel are washed up on Hamamachi beach in Hakodate, Hokkaido Prefecture, Japan, December 7, 2023. /CFP
Ealier this month on December 7, an estimated 1,000 tonnes of sardines and mackerel were found floating on the surface of the sea off the fishing port of Hakodate in Hokkaido, forming a silver blanket stretching for more than a kilometer.
City officials warned people not to eat the fish. As the fish were covered in sand, the officials said they can't be used as food or fertilizer for fish farming. Incineration is being considered, but the sheer mass of fish to be collected presents a daunting challenge.
Tens of thousands of sardines and mackerel are washed up on Hamamachi beach in Hakodate, Hokkaido Prefecture, Japan, December 7, 2023. /CFP
Experts have speculated that the migratory fish in both areas had been stranded after being chased to the point of exhaustion by amberjack and other predatory fish. Mass mortality events can also occur when there are sudden drops in the water temperature, causing the fish to go into shock, they added.
But no one has been able to confirm the cause. "The cause is unknown at the moment," said Mikine Fujiwara, a local fisheries official.