The Distribution of the Exotic Ascidian, Styela clava Herdman, in Cork Harbour

The solitary ascidian Styela clava Herdman is a native of the north-western Pacific and ranges from Japan to Siberia. It is believed to have been introduced to Europe on the hulls of warships following the Korean war, probably during 1952. It was first recorded from Plymouth in 1953. Since that time this species has been found at a number of localities on the S and W coasts of England, and across the Channel to Dieppe, France. The first record of this species in Irish waters was in 1972 from Cork Harbor, and this is still the only known Irish population.