Chub is a species of freshwater fish found mainly in running water throughout central and southern mainland Europe. It is not native to Ireland, but it has turned up here. How it got here is unknown. Chub are prized as a sport fish by some anglers so it is suspected that anglers may have introduced the species here for its sporting value.
While the sporting value of the Chub to anglers is not disputed, best practice dictates that a scientific assessment of any negative impact that a proposed introduction may have on our freshwater ecosystems should be carried out before any non-native species of fish is introduced to our waters.
Inland Fisheries Ireland (IFI) regard the Chub as an undesirable alien and a threat to our local wildlife as they have the potential to compete with our native fishes for food and space and are potentially a carrier of fish diseases and parasites. IFI is a statutory body whose principal function is the protection and conservation of Ireland's inland fisheries resource. IFI's position is backed by law; the introduction of Chub into Irish waters is prohibited, except under licence, by statutory instrument No 477 of 2011.
Chub have a voracious appetite and could do significant damage. Elsewhere, large adult Chub have been recorded eating considerable numbers of small fish as well as frogs, crayfish, voles and young water birds. They have even been observed eating berries such as blackberries and elderberry from trees overhanging the water.
The River Inny in Co Longford is the only Irish river in which Chub have been recorded. The alien fish were first recorded in the Inny, a tributary of the River Shannon, in 2001. IFI spent four years (2006-2010) trying to eradicate the species and prevent its spread into Lough Ree and the wider Shannon catchment.
It was believed that the invasive fish species had been controlled by electro-fishing but recently Chub have been reported again from the River Inny. It is not clear whether this is due to the earlier eradication programme not being as successful as originally believed, or whether the present fish are the result of a second illegal introduction.
IFI is investigating and appealing to anglers to protect our fisheries by not moving fish between watercourses and to submit reports of invasive alien fish to the IFI hotline 1850 34 74 24.