Discovery of 10,000 dead fish baffles environment inspectors

An urgent investigation has been launched by the Environment Agency after 10,000 fish died in an urban lake.

An urgent investigation has been launched by the Environment Agency after 10,000 fish died in an urban lake.

A hotline number has been opened by the agency, which said it was baffled by the deaths but was looking at the possibility of a mystery pollutant getting into the water.

Fisheries officers were called to Killingworth Lake, on the outskirts of Newcastle upon Tyne, on Monday when an angler reported dead fish in the lake.

As many as 6,000 roach and up to 1,500 perch, bream and carp have been collected from the lake and the agency expects another 2,500 fish to be recovered in the next few days.

Water samples from the lake, fast-tracked through the Environment Agency's laboratory in Leeds, have shown that the pH level of the water was average and while the level of oxygen in the water was low, it was not low enough to have caused such a major reaction.

Graham Siddle, spokesman for the agency, said: "We've never seen anything that has had such a devastating but localised effect like this. We're asking for every test we can to get as much information as possible.

"More than six square kilometres of land drain into the surface water system that empties into this lake, so we have a lot of ground to cover."

Improvement work was carried out at Killingworth Lake in January, including a habitat-creation project to provide a good environment in which young fish could mature.

Mick Donkin, ecological appraisal officer for the agency, said: "It's ironic that the success of this work has probably added to the death toll. We're picking up lots of young fish - between one and two years old.

"We've only got dead fish in a small area of the lake near where four pipes enter it, so something must have got into the lake and been diluted by the water so it only affected the fish in that area.

"The majority of the dead fish were in the pipes and it's likely they were feeding in there."

The agency's incident hotline number is 0800 807 060.