An investigation has been launched after a major pollution incident in which 100,000 gallons of slurry inadvertently released into a Co Tyrone river.
The incident occurred on the Owenreagh River near Dromore on Wednesday and it has been estimated 15 miles of water has been affected.
It happened when a slurry lagoon failed near Dromore.
In a statement the Loughs Agency said: "On Wednesday 23rd May, Loughs Agency received a call about a pollution incident on the Owenreagh River near Dromore, Co Tyrone.
"Agency staff located the source and are investigating the incident.
"Statutory samples have been taken and despatched for analysis.
"The investigation carried on during the night and the pollution has continued to move downstream into the Drumragh River.
"The Agency has unfortunately found evidence of dead fish.
"The Agency have deployed aeration equipment to re-oxygenate the water. The Northern Ireland Environment Agency has been advised of the incident and the investigation is ongoing."
The fish kill in the Strule is devastating. I have been in contact with the council who are working with other statutory bodies to limit damage. Aeration equipment is in place to reoxiginate the river. pic.twitter.com/byvT4oaZ0e— Chris Smyth UUP (@ChrisSmyth237) May 24, 2018
Ulster Unionist councillor Chris Smyth said hard lessons had to be learned from the incident.
“The scenes which I have witnessed downstream in the Strule river highlight the devastation which has resulted from this pollution incident," he said.
"Omagh as a town is situated on the river side and has a deep affinity with it.
“The local community has in recent times been very proactive in protecting the river and it is extremely disappointing to see so much of the good work undone by this pollution which has affected literally miles of the river.
“The river will take quite a while to recover but I am confident that the Loughs Agency, the Environment Agency and the council will do everything possible to minimise the damage and manage the situation as best they can.”
Sinn Fein MLA Catherine Kelly expressed concern about the amount of fish that have been killed as a result.
She said: "Up to fifteen mile of river could be affected, including the Drumragh which is an important salmon river and the Strule. There is extensive damage and a huge number of fish killed between Dromore and Omagh.
“I understand the Loughs Agency are investigating and taking emergency remedial action by aerating the river but it could take years for the river to repair itself.
“It is important that a full investigation is undertaken to determine precisely what happened, so that this devastating environmental damage and fish kill can be avoided in the future."