NEARLY 100 tonnes of dead fish have washed up on a Russian island in a mystery that’s left experts baffled.

Hundreds of thousands of Pacific herring were found dead over a 150ft stretch of Piltun Bay on Russia's Sakhalin Island.

5 Nearly 100 tonnes of dead fish were found washed up on the Russian island Credit: Central European News

Wildlife experts said the 93 tonnes of dead fish were piled up in 28 different clusters – some of them 12 inches thick.

A spokesman for the regional NGO Ecological Watch of Sakhalin said: "The death scale of the Pacific herring in Piltun Bay is enormous.

"The death of such an amount of uneven-aged fish of the same species is an abnormal event, and it may be a question of the destruction of a large part of the population of the herring of the bay."

The cause of death is still being investigated and samples have been sent to the Russian capital city of Moscow for testing.

5 Experts have been left scratching their heads over what killed all the fish Credit: Central European News

5 A local man stares at the masses of dead herring on Sakhalin Island Credit: Central European News

5 The fish were found dead over a 150ft stretch of beach on the island Credit: Central European News

5 Hundreds of thousands of Pacific herring were found washed up dead Credit: Central European News

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Social media users were just as baffled as experts as to what caused the disaster.

One said: "This is awful. This is some sort of a herring genocide. I really wonder what happened to them."

Another wrote: "Dear friends, words fail me! What happened there?"

Some suggested the massacre might have a dramatic effect on fish prices in supermarkets.

The Pacific herring is considered a keystone species because of its very high productivity and interactions with a large number of predators and prey.

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