DNA and morphological identification of an invasive swimming crab, Charybdis japonica, in New Zealand waters

Mitochondrial DNA sequences were used to identify an invasive swimming crab found in Waitemata Harbour, New Zealand. A 457 base sequence of the cytochrome oxidase 1 gene was compared in New Zealand specimens and nine species of Charybdis from Australia and Asia. The New Zealand specimens aligned with C. japonica. The diagnostic morphological characters of C. japonica were also checked in 54 specimens of the species collected in Waitemata Harbour, and concur with the mtDNA result. This is the first record of C. japonica establishing populations outside its native range. C. japonica, along with C. hellerii and the Lessepsian migrant C. longicollis, are the only known invasive species of Charybdis. C. japonica and C. hellerii are two of the few Charybdis species that inhabit the intertidal zone, and it is likely that the intertidal characteristics of these species contribute to their success as invasive species.