Inland Fisheries Ireland has said that silage effluent was responsible for a pollution incident that killed thousands of fish in a midlands river over the weekend.

The IFI confirmed this evening the incident occurred on the River Owenass and a minor tributary of the Owenass, near Mountmellick, Co Laois.

The species affected include primarily brown trout, and it is estimated that thousands of fish have been affected over a 6.5km stretch of the river.

Fisheries officers attended the site after receiving a report from a member of the public and immediately opened an investigation to identify the source of the fish kill.

In a statement this evening, the IFI said that "while the investigation continues, it would appear at this early stage that silage effluent was the potential cause of the mortality."

Inland Fisheries Ireland has a confidential hotline number to enable members of the general public to report incidents of water pollution, fish kills and illegal fishing (1890 34 74 24).