This small mussel is a native of the Caspian and Black Seas region and has been in Irish waters for only a little over a decade. A mainly freshwater species, zebra mussels can spread very quickly in the right conditions and have done in Ireland. They are now found throughout the Shannon and Shannon-Erne catchments, in the Grand Canal and in a total of over 50 lakes across Ireland. It is also possible that they are now in other catchments such as the Barrow / Nore.
Problems associated with this species include:
Zebra mussels are filter feeders and remove much of the plankton that juvenile fish depend upon and can cause other changes to water habitats. They attach to hard surfaces such as boats, buoys and water intake pipes, where they form reef-like clusters. They can block up water intake pipe, causing many thousands of Euros worth of damage.