VAST concentrations of dead fish have surfaced along the River Weaver in Winsford.

Eyewitnesses report thousands have perished along the water course, from the flashes down to Newbridge.

The Environment Agency (EA) has classed the incident as Category 1– its highest degree of severity.

The EA is awaiting laboratory results on water samples from the affected area to determine what caused the rapid de-oxygenation of the river.

The organisation has suggested natural, algae-related causes. Others involved in the cleanup operation suggest a deliberate dumping of toxins.

The EA is working alongside the Canal and Rivers Trust and Winsford and District Anglers Association (WDAA) to return oxygen levels to normal.

The slick, or ‘slug’ of the de-oxygenated water took one day to travel from Bottom Flash to Newbridge, just beyond the Winsford Salt Mines, off New Road.

The water at Newbridge would usually read between 50 to 100 per cent oxygenation.

An early reading by the EA returned a reading of just 2 per cent.

The EA set up aerators – water pumps designed to increase the amount of oxygen in the river - on Sunday.

On Monday morning, further EA employees arrived to set up jet hoses, which fired hydrogen peroxide into the water, releasing concentrated bursts of oxygen.

Guy Humphreys, fisheries manager for WDAA described the moment he discovered the dead fish.

He said: “I got a call about a tree that was down, overhanging the water. I went to have a look and noticed in the river there were all these dead fish.

“There were so many dead or dying that I could have walked across the water on them. There’s tens of thousands of fish have been killed.”

Mr Humphreys promptly phoned the EA.

Meanwhile, people back up the river in Winsford began to witness the grizzly scene at the flashes.

Deputy mayoress of Winsford, Hilary Kennedy, said: “I was on the high Street walking the dog when a friend of mine came towards me from the direction of the flashes and stopped to talk.

“She told me that she was shocked to see there were a lot of dead fish in the water around the marina, the Town Bridge and all along the river.

“She said that there were policemen there and a heck of lot of other men, plus someone in a canoe.”

The river has a rich diversity of species, including bream, roach, silver fish, carp, tench, perch and pike.

Jane Hamilton, fisheries and biodiversity team leader fo the EA, said: “Officers have been working around the clock to identify what was affecting the fish, and taking action to help them.

“We know there are very low amounts of oxygen in the water and we think that this could be due to a naturally occurring algae.

“We have been investigating the cause, and will know more following results of tests later in the week. Once we have this information we can look into further options to tackle the problem.”

EA employees worked until midnight on Sunday.

However, Mr Humphreys felt the organisation could have responded to his call earlier.

“I called it in about 3pm on Saturday, and unfortunately no one’s been available to come down and have a look until Sunday morning. During that time, it’s continually killing fish,” he said.

At 8am on Sunday, Guy was phoned by Winsford Town Clr Brian Clarke, who had also called the disaster in to the EA.

Mr Humphreys continued: “At 9.30am, a man from the EA turned up. We went up and down the river and took oxygen readings. It was dinner time by the time we got the oxygenation equipment set up.

“If EA had been quicker, we could have averted this, but they don’t have the man power. I don’t blame the people on the ground. They were working very hard.

“It’s a major disaster for us. We had an incident on the River Dane a few years ago. The stocks in the area were just recovering from that, but this has just killed it.

“It takes 15-20 years to get stocks back up to the way they were. It’s soul destroying. It’s not just fishing either, there’s the knock on affect on all wildlife in the area.”

On the cause, Mr Humphreys said: “Up to now we’re presuming somebody has tipped something in.”

The WDAA is one of many regional voluntary organisations that maintain fishing spots in their local area out of their own pockets.

Secretary of WDAA, Steve Beech, called for national reform on the way rivers are managed.

He said: “Last time we had pollution like this was in 2008, and the people responsible were fined £80,000.

“It’s a national disgrace that the agency that deals with these incidents is underfunded by this Government. They do their best with limited resources and limited manpower.

“It shouldn’t be left to a group of volunteers to monitor water quality. Angling is the country’s biggest participation sport. It should be funded sufficiently to maintain the quality of waterways.”

- Children’s summer canoeing sessions due to take place at Winsford marina have been suspended for the week.

- It is hoped the duck race, planned for Bank Holiday Monday, will go ahead. Tickets are still available for the event. Call WINCAP on 01606 551766 for details.