INLAND FISHERIES IRELAND has said it is investigating the re-appearance of the invasive fish species Chub along the River Inny in Co Longford.

The state agency has expressed concerns that the re-appearance of the fish presents a “real and pending concern” to the biodiversity of the Shannon, which the Inny flows into. 

It says that Chub have the potential to compete with native Irish fish for food and space and that they are potentially a carrier of diseases and parasites.

“IFI is investigating the extent of the invasion and assessing strategies for eradication and control,” a statement said.

“The threat of Chub spreading through the Shannon system is of real and pending concern to the biodiversity of Ireland’s biggest catchment.”

The agency confirmed the presence of the fish after a Chub was caught at a location identified by IFI staff, who had recorded potential sightings at several locations.

That followed sightings by the National Biodiversity Data Centre by members of the public.

Chub are non-native in Ireland, and the River Inny is the only Irish river in which they have been recorded.

The species was initially subject to removal operations between 2006 and 2010, and it had been hoped that the species had been eradicated from Irish waters.

“It is unclear at this stage whether these fish represent growth in the original population or are as a result of a second introduction,” IFI said.

“Inland Fisheries Ireland are endeavouring to establish the status and distribution of the species within the catchment which will help inform potential management programmes.”

Dr Cathal Gallagher, IFI’s head of research, explained that non-native fish species threaten Irish ecosystems in unforeseen ways, and are therefore a cause for concern.

“We would appeal to anglers to protect our fisheries by not moving fish between watercourses for any reason and submit any sightings directly to IFI or through the IFI hotline on 1850 34 74 24,” he said.