More than 20,000 fish found dead in Co Louth river pollution incident

Authorities are investigating a significant fish kill in Co Louth (David Cheskin/PA)

More than 20,000 fish have been discovered dead in the River Glyde in Co Louth, Inland Fisheries Ireland (IFI) has said.

The state agency said the “locally significant fish kill” was reported on Tuesday evening and affected a “considerable stretch of the river”.

Speaking on RTÉ Radio 1’s News at One, Ronan Matson, director of the IFI’s Eastern River Basin District, said he believed the incident had been caused by an agricultural discharge upstream of Tallanstown.

The IFI has taken samples of river water for laboratory analysis to confirm the cause and said local authorities have been notified.

Mr Matson said all species of fish in the river have been impacted, but the majority of the dead fish were minnows and sticklebacks.

Salmon, eel, brown trout, roach and pike have also been killed.

Monitoring and assessment of the impact will continue to be carried out by IFI staff.

“Recovery will start immediately… the pollution will wash out relatively quickly,” Mr Matson said.

“But it can take a few years for the fish to come back.

“So if there are fish there that are two or three-years-old it will take that two or three years for those fish to recolonise.”

He said it was “good news” that most spawning happens upstream of the affected area.

“So there should be good regeneration, once the source of pollution has stopped, which we are confident it has.”