"It is shameful that something like this can happen in this day and age

Robin Darker of the Welsh Federation of Coarse Anglers

Environment Agency officials say they have traced the company responsible for the fuel spill and are in the process of compiling evidence for prosecution.

They have refused to name the firm but have said the spill came from a disused fuel tank.

The company is co-operating fully with the clean-up operation and weather conditions are helping, with the wind helping the fuel to evaporate.

The affected lake is part of the �27m Llanelli Millennium Coastal Park project. The incident is the second pollution blow - following the discovery of blue asbestos last November.

Rescue hindered

Environmentalists are concerned that the surviving fish are being attracted to the culvert where the fuel entered the lake, and experts are working on ways of keeping them away from the area.

Anglers are saddened by the toll of dead fish

Efforts on Tuesday to net them away from the pollution were hindered by metal spikes on bottom of the lake which were put there to stop poachers.

Fire officers have checked the surrounding area and have confirmed there is no risk to residents.

Park director Gerry Phillips said : "This is a very serious incident and I am furious at the speed with which it affected so many fish in the lake.

"We are determined to ensure that public safety and protection comes first."

Fishermen angry

Robin Darker from the Welsh Federation of Coarse Anglers, said he was angered by events.

"It is shameful that something like this can happen in this day and age.

"People have to be more aware of what pollutants can do to various wildlife."

The coastal park hosted the National Eisteddfod last year and work to create a national angling centre are due to be completed this summer.