MYSTERY surrounds the sudden appearance of dead fish and eels in a Chester nature park.

The Environment Agency has investigated reports of pollution at the brook in Caldy Nature Park, Boughton Heath, and found nothing amiss.

But a volunteer group that looks after the reserve maintains there is something fishy about the situation.

The Leader was alerted to the situation by Julie Casey, secretary of Friends of Caldy Nature Park.

She and other members were particularly concerned about the effect on the European eels, which are a critically endangered species.

They suspected a “serious water pollution incident” early last week when the colour of the water changed.

“The pollution was first noticed on Tuesday morning when the water in the brook was a strange colour,” said Julie.

“The following morning local residents found dead eels and fish in the brook. This is particularly upsetting as eels are a critically endangered species and earlier this year an eel pass was constructed in the brook to assist the eels with their migration.”

However, an Environment Agency spokesman said the water was running clear when an officer went to investigate, despite the presence of large amounts of litter.

He said: “We can confirm we received a report on Tuesday, August 1, of a green patch of water in Caldy Brook and of dead fish in the water.

“An environment officer went to the brook and although they found six dead sticklebacks next to the bridge there was no sign of pollution in the water which was running clear.

“There was a substantial amount of litter in the water and this is believed to have been caused by heavy rain. Welsh Water kindly offered to undertake a litter pick and have also offered any further support we may need with our follow up investigations.”

People should report pollution incidents to the agency's 24 hour Incident Hotline on 0800 807060.