WILDLIFE in a river has been put at risk and dozens of fish killed after the Environment Agency opened a sluice gate, leaving a west Suffolk river almost dry, according to a conservation group.

Yesterday morning, members of Swan Watch in Sudbury were shocked to find an offshoot of the river Stour, known as Mill Cut, virtually empty of water and littered with dead or dying fish.

A swan nesting on the bank was also left high and dry as thick mud replaced flowing water.

Early-morning walkers and guests at the nearby Mill Hotel were asking: “Where has all the water gone?”

Because of flooding caused by recent downpours, the agency took the decision to open the Croft sluice gate at 1.30pm on Wednesday after heavy rain was forecast for later that evening. The rainfall was nowhere near as heavy as predicted, but the gates were still open 24 hours later.

When the gates are closed, water is channelled toward a mill pond via Mill Cut. If water levels rise, the gates are opened to allow water to flow out of the river and minimise the risk of flooding the common land meadows, where cattle usually graze.

Chris Harvey and Roy Spicer, who run the Swan Watch group, initially contacted the agency late on Wednesday afternoon. They also put in a call on Thursday morning asking for the gates to be closed as a matter of urgency.

Mr Spicer said: “When I arrived at the river this morning, I couldn’t believe it. There were just puddles of water left and the fish that hadn’t already perished were gasping for air because there was no oxygen in the water.”

Mr Harvey added: “Wildlife is facing enough threats at the moment and I feel gutted about this situation because it could have been avoided. We did warn the agency that they needed to get down here immediately and we were told someone would be out some time during the day.”

An environment agency spokesman told the EADT yesterday afternoon, that based on Met Office forecasts for heavy rain overnight, they had opened the sluice gates to prevent flooding.

He added: “Our officers returned to close the gates this afternoon. We are unable to confirm the reported fish deaths and these could have been due to natural causes.

“However, we will review the operation of the mill gates for future flood events.”

Mill Cut is usually home to fish such as perch, roach and rudd, and swans use it as a sheltered place to nest.

Sudbury Common Lands ranger Ian Crighton insisted that the wildlife was in no serious danger, adding: “They (the Environment Agency) have to open the gates to keep the river at proper levels, because everything comes out on to the meadows and we can’t put the livestock on there.

“Fish can survive for some time in very little water and we knew the agency would come out and close the gates again at some point today.”