Fish checked in River Churnet after chemical incident
The Environment Agency is checking fish stocks in a Staffordshire river two years after more than 700 were killed by a chlorine leak.
An electric current will lightly stun fish in the River Churnet in Leek so they can be counted easily.
The agency said it wanted to see if numbers were recovering after Severn Trent admitted a clip had corroded on an underground pipe, causing the leak.
It was fined £15,000 and paid thousands of pounds for the clean-up.
'Five years recovery'
A total of 740 dead fish were found, including 344 brown trout, the agency said.
The water company said as well as the metal clip failing at its treatment works in Tittesworth, near Leek, in December 2008, a secondary pipe, which should have contained any leakage, had been incorrectly connected and failed to stop the pollution reaching the river.
It was estimated at the time that stocks could take five years to recover.
A spokesman for the Environment Agency said: "Severn Trent offered to pay £63,500 to restock the river, but we want the fish population to recover naturally so the river can keep its genetic integrity.
"Severn Trent paid £32,600 to 'tanker' away the chemical, £8,300 to plug the leak, £6,000 on an initial fish survey, £60,000 on installing new equipment to detect a leak, £2,271 to us for our officers responding to the incident, and £20,000 for further fish surveys."