Thousands of fish and insects killed as unidentified substance pollutes Somerset river

Twelve-year-old boy alerted Environment Agency to pollution with photo of dead fish he pulled from River Sheppey

A 12-year-old boy removed these fish from a small stretch of the river and staged the photograph for the Environment Agency (Environment Agency Wessex/Facebook)

Thousands of fish have died after an unknown source polluted a 9.3-mile stretch of the River Sheppey in Somerset.

The Wessex branch of the Environment Agency said it had tracked the pollution to a “probable source” and were working to protect the lower end of the river.

“But the pollution has likely killed thousands of fish and invertebrates,” the agency wrote in a Facebook post.

The agency also thanked an unnamed local child, who had noticed the dead fish and alerted them to it.

It said in its Facebook post: “We are very grateful to a 12-year-old boy who removed fish from a small stretch of the river, put them in his bucket, then staged a photograph for us.”

The agency was spraying hydrogen peroxide and aerating the water in an effort to clean up the river and rejuvenate its oxygen supply.

The latest pollution incident is the second such incident in a week.

On Thursday, more than 6,000 fish died after a pollution incident on the River Mole in South Molton, Devon.