Dace (Leuciscus leucisus)

The dace is native to most of Europe and Siberia, but it is not native to Ireland. Dace were introduced to the Munster Blackwater in 1889 as live bait, along with roach, by anglers visiting from England. Although they have not spread as prolifically as roach, dace have unfortunately also become an invasive species where present because they grow rapidly and reproduce in high numbers, competing with native species, such as brown trout and salmon, for food and habitat. They can particularly reduce the breeding success of salmon because these species compete for their preferred spawning habitat in well-oxygenated gravels. Dace have spread to a number of other river systems across Ireland, including the Barrow, Nore, Suir and Shannon catchments.

Dace are a slim, silvery fish that have yellow eyes, which distinguishes them from roach, which have red eyes. They can also be distinguished by the dorsal fin on their backs and anal fin on their bellies, which both have a concave edge. Dace swim close to the surface and can appear in dense shoals. Dace like to inhabit fast flowing, clean water, particularly in the middle to lower reaches of rivers. They eat insects and crustaceans, and they also graze on algae and aquatic plants. Coarse anglers can catch dace in large numbers where they are present due to their shoaling behaviour.

Dace caught in the Munster Blackwater in 2016.

Dace (Leuciscus leuciscus L.): an Invasive Fish Species in Ireland

Dace (Leuciscus leuciscus L.): an Invasive Fish Species in Ireland

Published on 7 Sep 2010
  • Research
  • Research theme: Invasive species