Conservationists are “extremely worried” amid reports of 100 dead fish at a nature reserve as the Environment Agency investigates “potential pollution”.

A nearby resident alerted Maple Lodge Nature Reserve after finding dead fish in “milky” discoloured water along a stream – known as Maple Lodge Ditch - that feeds into its lakes on Saturday, October 12.

This was then raised with the Environment Agency which confirmed it is investigating what happened as a “potential pollution”.

(Image: Maple Cross and West Hyde Residents Association) The Maple Cross and West Hyde Residents Association and the nature reserve have said they are “extremely worried” about the impact on wildlife.

Maple Lodge Conservation Society chairman Keith Pursall explained that it is still unclear what has caused the deaths, including whether it is toxic and could therefore spread to fish-eating animals.

The society have apparently counted more than 100 dead roach and "four or five" large fish in the reserve’s lakes have also been found dead.

(Image: Maple Cross and West Hyde Residents Association) Kingfishers, herons, egrets, other fish-eating birds, and water voles – a threatened species – also inhabit the nature reserve.

“It’s extremely worrying that this has happened,” Mr Pursall said.

Carolyn Weston, from the resident’s association, added: “It’s important that that we ascertain what the chemical is that’s done the damage so we can determine the knock-on effect, because from the nature reserve it goes on to the river Colne.”

(Image: Maple Cross and West Hyde Residents Association) BCL (Maple Cross) LLP, which has two warehouses due to be completed this year in development near Maple Lodge Ditch, has confirmed the Environment Agency is investigating potential pollution of the water.

“A short length of the watercourse flows to the west of our development site at Maple Cross and our team is fully supporting the Environment Agency’s enquiries,” a spokesperson said.

“We regard sustainable operations and environment protection as matters of the highest priority and always ensure appropriate protocols and safeguards are in place.

(Image: Maple Cross and West Hyde Residents Association) “All operations at the Maple Cross development site are carried out under the Construction and Environmental Management Plan that was agreed with the local authority.”

An Environment Agency spokesperson said: “Our team was made aware of a potential pollution of the ‘Maple Lodge Ditch’ in Maple Cross on October 12, 2024.

“As this is an ongoing investigation we cannot disclose any further information at this time."