Hemimysis anomala is established in the Shannon River Basin District in Ireland

The Ponto-Caspian mysid shrimp Hemimysis anomala was found in Ireland for the first time in April 2008. During 2009 it was found throughout most of the Shannon River Navigation (similar to 250km) occurring in swarms at estimated densities of similar to 6 per litre in shallows and in lower densities at depths of similar to 20m where its distribution overlaps with the native Mysis salemaai. Broods were found from March to September. It occurs mainly in lakes but small numbers were found at one river site. In summer, shallow-water specimens were found only during the night but in winter could be captured in daytime. It is not known by what means the species arrived in Ireland, or when.