Evidence for the Invasion and Successful Establishment of Hemigrapsus Takanoi Asakura & Watanabe, 2005 (decapoda, Varunidae) in Great Britain

Following the recent discovery of the brush-clawed shore crab, Hemigrapsus takanoi Asakura & Watanabe, 2005, in Great Britain, new data are presented here on the occurrence of this species from additional locations, five in north Kent and one in Suffolk. This study provides significant evidence to suggest that in Suffolk the species has become well established and now forms a large reproducing population. A new earliest date for introduction of the species to Great Britain is given and the possible vectors involved at the various localities in the SE of England are discussed. Management and eradication of H. takanoi from this area are now considered to be unfeasible. The future spread and potential impact of H. takanoi in Great Britain should be carefully monitored.