More than 20,000 fish killed after river polluted

Atlantic salmon are among the species of fish killed./SCREENGRAB

More than 20,000 fish have been killed after a river in the Republic of Ireland was polluted.

Inland Fisheries Ireland (IFI) said the "harmful ecological event" at the River Glyde near Tallanstown in County Louth was discovered on Tuesday.

Species of fish discovered dead include adult and juvenile Atlantic salmon, eel, brown trout, pike, and coarse fish.

In a statement IFI said a definite line of enquiry is being pursued, and local authorities have been notified.

The agency's eastern river basin district director Ronan Matson told Irish broadcaster RTÉ the cause is believed to be an "agricultural discharge upstream of Tallanstown".

"Right now, you can see a few dead fish around Tallanstown," he said.

"Where I am it's kind of washed down a bit but there are other locations where there are thousands. So the current estimate is in excess of about 20,000 fish."

He said the majority of dead fish are made up of minnow and stickleback, which are both tiny, common, freshwater fish.

A water sample has been sent on for testing to confirm the cause, Matson said, and river recovery will begin immediately.

"Pollution will wash out relatively quickly, but it can take a few years for the fish to come back," he said.

Matson added that the pollution appears to have occurred away from where "most of the spawning seems to be occurring".

"So, there should be good regeneration once the source of pollution is stopped, which we're confident it is," he said.