A major fish kill in a County Londonderry river is believed to have been caused by agricultural effluent, investigators say.
Several thousand fish have died since the pollution spill at the River Faughan on Monday, officials say.
The Department of Agriculture, Environment and Rural Affairs (DAERA) has said the fish kill stretches over several kilometres.
A department spokesman said the cause is “suspected to be silage effluent”.
‘Several thousand dead fish’
Anglers reported dead fish in two separate locations on the river. One near Claudy village, the other much further downstream at Campsie, close to where the Faughan runs into the River Foyle.
The Loughs Agency said it was investigating whether there were two separate pollution events, or both were part of the same one.
Norman Henderson, from the Northern Ireland Environment Agency (NIEA), said it would take many months for the river to recover.
“It’s a significant kill, there’s no doubt about that. The latest figures we’re getting from the Loughs Agency is several thousand dead fish,” said Mr Henderson.
“We believe it is agricultural and we have narrowed it down to a particular part of the river and we are following a definite line of inquiry.
“It would obviously have to be a fairly strong effluent, something like silage.”
But there was no risk to public health, said Mr Henderson, who is a senior scientific officer with the NIEA.
“The river is safe in the sense that it has affected the fish but there is no risk to drinking water,” he said.
“The river will recover, its difficult to put an exact timescale on it but you’re certainly talking many months or possibly longer before the river is back to normal.
“Certainly the overall stocks in the river will still have taken a hit.”
The River Faughan is an important waterway for breeding salmon.
It also contains sea trout, trout, lamprey, eel and many other fish species.
‘Major pollution tragedy’
East Londonderry MP Gregory Campbell has written to the Environment Minister Michelle McIlveen seeking answers.
“This is a major pollution tragedy on the Faughan which is a well-known salmon and trout river in the North West for anglers,” he said.
“The wider implications on this major fish kill for future generations of fish stock cannot be underestimated and it is imperative that the source of the pollution is found as soon as possible to minimise further losses.”
Sinn Féin MLA Caoimhe Archibald asked whether enough was being done to prevent such incidents.
“This incident needs to be fully investigated, those responsible must be held accountable and brought before the courts,” she said.
“The penalties imposed for incidents such as this should be as severe as the law allows.
“At times the fines are not a sufficient deterrent and do not match the damage being done to the environment.”
SDLP MLA for East Londonderry Gerry Mullan described the scene as like “something out of a horror movie.”
“The news that in excess of 1,000 fish near Claudy have been killed is deeply disturbing, with eyewitness reports that this was like something out of a horror movie,” said Mr Mullan.
“Causing water pollution is a criminal offence and whoever is behind this must be brought before the courts,” he said.
“It is unclear how long it will take before the stretch of water recovers. I will be seeking a full report from the environment minister on this shocking situation.”
Courtesy of BBC News