Inland Fisheries Ireland (IFI) has welcomed a conviction it secured against Uisce Éireann after a sewage discharge polluted a popular angling lake in Co. Mayo which killed almost 1,000 fish.

The case, held recently at Castlebar District Court, heard that effluent from Uisce Éireann’s wastewater pumping station in Claremorris flowed into Clare Lake, killing at least 945 fish over a two-week period.

The utility was found to have committed a water pollution breach, and must pay a fine of €4,000 and €7,131 in costs and expenses to IFI.

IFI said that the pollution incident occurred on April 26, 2024 and may have also had a secondary impact on water quality in the River Robe as the lake forms part of its catchment.

Commenting following the case, Dr Rachel Cooper IFI’s Galway director, said that "a large number of fish, including perch and roach, were impacted in this very damaging event".

"It may take years for Clare Lake to recover. Pollution incidents such as these severely affect water quality and pose a serious threat to our natural environment, and fish stocks," she added.

According to IFI, the lake is a well-used and very important local angling amenity, with floating fishing stands, wheelchair access, and seating areas for members of the public.

These works were completed by IFI in 2016, in conjunction with a local community employment (CE) scheme initiative.

Established in 2010, IFI is the State environmental agency responsible for conserving, protecting, and managing Ireland's inland fisheries and sea angling resources.

The agency, which employs 320 people across the country, has statutory responsibility for Ireland’s 74,000km of rivers and streams, together with 128,000 lake hectares. It also has a coastline patrol jurisdiction of 12 nautical miles.

Its core mission is to protect freshwater fish and their habitats and operates under the Department of the Environment, Climate and Communications (DECC).

IFI continues to urge the public to report instances of water pollution, fish kills, habitat destruction, or illegal fishing, to its confidential 24/7 number, 0818 34 74 24.

In a statement, Uisce Éireann said that it is committed to safeguarding public health and protecting the environment in all its activities.

"Following an overflow incident in April 2024 which regretfully resulted in a fish kill in the Clare Lake, Claremorris, we put in place a number of measures to reduce overflows at Clare Lake and ensure such an incident does not recur," the company said.

The infiltration works, which saw an investment of €1.5 million, included the following:

Rehabilitation of 2km of sewer pipelines in Claremorris town to reduce the volume of ground water entering Mayfield pumping station;
Replacement of foul pumps to increase throughput at Mayfield pumping station;
Improvements to telemetry and monitoring at Mayfield and connection to the national telemetry system (INTS).

In addition, Uisce Éireann also recently completed works to reconstruct a section of sewer near Mayfield where significant ground water infiltration was occurring.

The company said that reinstatement works on site will be completed shortly.