Environment officer Shani Gaskell checks oxygen levels in Hinksey Lake About 1,000 dead fish were found in an Oxford lake as a result of 10 months of below average rainfall followed by sustained downpours.

The fish were found dead in Hinksey Lake, South Oxford, on Wednesday. Two days earlier, hundreds were also killed in the River Cherwell in Banbury.

Environment Agency officers investigated both incidents and found that the sustained hot weather had caused algal blooms at Hinksey Lake. When the blooms die, bacteria feed off them and use up the oxygen fish rely on.

Agency officers have installed aeration equipment to pump oxygen into the water.

Initial investigations suggest that the fish in the Cherwell were killed by polluted rainwater which entered the river from drains in Banbury during down- pours last weekend.

Petrol and diesel deposits on the roads would have been washed into the drains, which discharge into the river.

The Cherwell suffers from low flows during the summer and so its ability to dilute contaminated water is reduced, increasing the environmental impact.

Agency environment manager Sally Coble said: "We are currently exper- iencing an increase in incidents like this across the Thames Valley, as a direct result of an exceptionally dry winter and summer.

"I'd ask anyone who sees dead fish or fish gasping for air to report this to us on our emergency hotline, 0800 807060.

"But the public can also help avoid situations like this by limiting the amount of water they use.

"This will reduce the amount of water that needs to be extracted from our lakes and rivers and from underground sources that feed our rivers, lakes and ponds, minimising the environmental impact this can have."