Date of introduction and origin
Rhithropanopeus harrisii was first found in Roath
Docks, Cardiff, South Wales, in 1996. It is not known where the
introduction came from, although this species is native to the east
coast of the American continent from New Brunswick to north-east
Brazil (Christiansen 1969).
Method of introduction
The method of introduction to Britain is unknown but was
probably in association with ships, possibly in ballast water or
clinging to hulls. Ships arrive in Cardiff Docks from all over the
world, including coal barges from the U.S.A. It was first observed
in Europe in the Zuiderzee, The Netherlands and Christiansen (1969)
consider it probably arrived in the ballast or on the hulls of
Reasons for success
Its reason for success is unknown. However, the dock water in
which Rhithropanopeus harrisii has been found is of low
salinity (about 12%o).
Rate of spread and methods involved
Rhithropanopeus harrisii spread through much of
continental Europe between the 1870s and 1950s (Christiansen 1969).
However, it has only very recently arrived in Britain. Its spread
in Britain is unknown, and so far it has not been found outside
Cardiff Docks. Its spread is probably associated with
In Britain this species has only been recorded as established
throughout Cardiff Docks. Elsewhere in Europe it is found in
Denmark, Belgium, The Netherlands (where it is much less common
than previously), Poland, West Germany and France, and in Russia,
Romania and Bulgaria - from the Black and Caspian Seas and also in
the Sea of Azov (Christiansen 1969).
Factors likely to influence spread and distribution
Shipping routes are likely to affect the spread and
distribution of this species.
Effects on the environment
Effects on commercial interests
Control methods used and effectiveness
Cardiff Docks harbour other non-native species, including the
tube worm Ficopomatus enigmaticus, with which R..
harrisii may associate, possibly on trophic levels.
Ingle, R.W. 1980. British crabs. London & Oxford,
British Museum (Natural History) & Oxford University
Christiansen, M.E. 1969. Marine invertebrates of
Scandinavia. No. 2 Crustacea, Decapoda, Brachyura. Oslo,
Acknowledgements (contributions from questionnaire)
Dr C. Mettam, University of Cardiff.
P.F. Clark, Natural History Museum, London.