About Helice tridens (De Haan, 1835)
Helice tridens (De Haan, 1835) is a species of crab that inhabits mudflats along the coasts of Japan and the Korean Peninsula. It is a semi-terrestrial species, and returns to the sea to spawn. The invasive predatory raccoon (Procyon lotor) appears to have an adverse effect on H. tridens populations. This crab species has a salinity requirement that falls between those of two other estuarine crab species found in Japan: Helicana japonica and Chiromantes dehaani. Smaller H. tridens individuals shelter in burrows located in reed marshes, likely to avoid cannibalism from larger individuals. This same cannibalism avoidance may explain why larger crabs migrate to brackish water lagoons during summer, when the crab population exceeds the carrying capacity of their original habitat.
