Estuarine mud crab (Harris mud crab, white-fingered mud crab) in Denmark: Old guest and new invasive species
Rhithropanopeus harrisii has been recognized in Europe since 1949. It was, however, introduced from the American east coast at least 75 years earlier, but was described and became known under another name, the Zuidersee crab (Pilumnus tridentatus Maitland, 1874). In Denmark it was found for the first time in 1953 in the harbour of Copenhagen. It seems to have been absent for more than 50 years, until it turned up again in 2008 in southern Denmark (Nysted Nor, the Baltic coast of Lolland) and around Copenhagen. It was reported also in 2009 and 2010 from the earlier known localities and some new in southern Zealand. A specimen with 28 mm
carapace width is the largest ever recorded for the species.