Scientific nameCharybdis japonica


Marine, Terrestrial


English: Asian crab, paddle crab, Asian paddle crab, swimming crab, blue crab

Charybdis japonica have a carapace width of up to 12cm (Gust et al. 2003). They have a pilose (hairy) carapace (although amount of hair varies to little or none). The carapace has ridges with six frontal teeth, triangular and sharp. The inner supraorbital lobe is broadly triangular (Smith et al. 2003). Wee and Ng (1995) record the colour of C. japonica in Japan as mottled cream and purple. In the Waitemata harbour (New  Zealand) specimens varied from pale green and off-white, through olive green to a deep chestnut with purplish markings on the carapace and upper surfaces of the appendages (Smith et al. 2003). In addition, most Waitemata specimens have yellow-orange markings, some with only a hint of yellow-orange and some with very noticeable brown-orange on parts of the carapace and the legs, especially on the chelae where the upper colouration grades into the white to off-white ventral surfaces (Smith et al. 2003).


ASEAN: Malaysia, Thailand
World: China, Democratic People's Republic of Korea, Republic of Korea, Taiwan


New Zealand
Transport – Ship/boat ballast water


The paddle crab may have been introduced from ship ballast water (Gust et al. 2003). This is known to be a potential route of spread of the Asian paddle crab.

Disease transmission is one of the key potential impacts of the paddle crab in introduced environments. C. japonica is known to be a host or carrier of the White Spot Syndrome Virus (WSSV) (Maeda et al. 1998, in Potential next pests 2003). WSSV is a serious fisheries threat as it infects a broad spectrum of crustaceans, and can cause cumulative mortalities of up to 100% within 3 to 10 days from the first sign of disease
(Lightner 1996, in Potential next pests 2003).
Source: Global Invasive Species Database (GISD) 2015. Species profile Charybdis japonica. Available from: [Accessed 09 September 2019]
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Last updated on 09/12/2019 22:39