A pollution incident on the Carrowbeg River in Westport last weekend was linked to an accidental discharge of detergent into the river.
Inland Fisheries Ireland investigated the incident after receiving a number of calls to their hotline number on Saturday .
Locals reported that an excessive amount of foam had appeared in the river.
The source was identified and immediate remedial works were carried out.
Inland Fisheries Ireland says their staff have carried out kayak and drone surveys of the catchment area to assess possible fisheries implications, and the surveys to date have not found any evidence of a fish kill resulting from the incident.
Fisheries staff are continuing to monitor the site, as the Carrowbeg river - which runs through Westport town - has an abundant indigenous brown trout population, and is an important amenity to the local community.
Members of the public are urged to report any suspected pollution incidents to the Inland Fisheries 24-hour confidential hotline on 1890 34 74 24.