River Mole: Environment Agency investigates after dead fish found

The Environment Agency has deployed equipment in an attempt to re-oxygenate the water

The Environment Agency is investigating after reports of dead fish along a stretch of the River Mole, near Gatwick, in Surrey.

Geographer Simon Collins, who lives in Reigate, tweeted he had seen "many fish dead or struggling" on a 1km (0.6 mile) stretch downstream from Man's Brook.

The Environment Agency said oxygen levels were "significantly reduced" along the impacted stretch.

It said it was looking into whether it was due to pollution or natural causes.

Mr Collins tweeted pictures of the fish he had seen and reported "widespread fish death".

He said dissolved oxygen levels were at 9% and efforts to oxygenate the stream were taking place, with pumps running overnight.

A number of factors can affect the amount of oxygen dissolved in water, and good levels are critical for the health of a river system.

On Monday, the Environment Agency tweeted that it had received calls about fish in distress.

It said this was "due to the warmer weather and heavy rain which reduce the oxygen in water in some areas".

In a statement on Tuesday, it added: "Initial investigations have established that dissolved oxygen levels are significantly reduced along the impacted stretch of river.

"Our officers are deploying equipment in an attempt to re-oxygenate the water.

"An investigation is being undertaken to establish whether the low dissolved oxygen is a result of pollution or natural causes."

Follow BBC South East on Facebook, on Twitter, and on Instagram. Send your story ideas to [e-mail].