BROWN trout are spawning in the River Thames in Oxfordshire for the first time in more than 20 years.

The fish have moved into an area of the river near Eynsham that the Environment Agency worked on in 2007 to improve breeding grounds for coarse fish like chub and barbel.

The presence of young brown trout, which are thought to be about 15 months old, has been hailed as an unexpected bonus of the agency’s work.

Chris Bell, an agency fisheries officer based at Wallingford, said: “Brown trout indicate good water quality and also good habitat.

“The important thing for us was we found the fish in the exact location where we carried out improvement work on spawning grounds for fish.

“It was done for the usual Thames fish like chub, dace and barbel, so to find brown trout there is the cherry on the cake.

“It was something we hadn’t really expected and it does show the success in what we were aiming for.”

The project restored a 300-metre section of river known as the Eynsham Loop.

The £13,000 scheme was largely funded by the sale of anglers’ rod licences and saw about 40 tonnes of gravel placed on the river bed and new trees planted.

Limestone rocks were also used to raise the river bed in five areas, creating shallow areas of clean gravel with fast flows across them.

Mr Bell added: “There are brown trout elsewhere in the county, but all of these fish have been stocked into weir pools or come from Cotswold tributaries.

“This is the first time we’ve found direct evidence of them reproducing in the river.”

Asked whether anglers could wipe out the stocks, Mr Bell said he very much doubted it saying most anglers were “natural conservationists”.