MORE THAN 10,000 protected lamprey were among thousands of fish killed in a suspected chemical poisoning along a small Tipperary river earlier this month.

An investigation is underway after Inland Fisheries Ireland confirmed that nearly 15,000 fish were killed on the Ollatrim River, a tributary of the Nenagh River, on the weekend of 7-8 July.

Locals first reported seeing dead fish in the river on 7 July, before the agency inspected a site at Ballinahemery Bridge near Ballymackey, Nenagh on 9 July.

Dead fish were observed over a 5km-stretch of the river, with Inland Fisheries Ireland estimating that 14,749 fish were killed in total.

The dead fish included around 10,500 lamprey, 1,820 minnow, 1,400 brown trout, 805 stoneloach, 84 stickleback, 70 salmon, and 70 crayfish.

Some of the dead lamprey in the Ollatrim River Inland Fisheries Ireland Inland Fisheries Ireland

The agency reported that the incident was the largest kill of lamprey in recent years, and anticipates that the recovery of the species will take several years.

It also suspects that a chemical agent, possibly a herbicide or pesticide which passed through the river, is responsible for the kill.

In a statement, the agency reminded the public and the farming community to be aware that herbicides and pesticides are extremely toxic to aquatic species and fish.

It also said that mixing of chemicals must be done far from natural watercourses, especially in current conditions when diluting waters are in short supply and the toxicity of chemicals is increased.

Inland Fisheries Ireland added that its confidential hotline is available to members of the public who wish to report water pollution incidents on 1890 34 74 24 or 1890 FISH 24.