Occurrence Pattern and Behavior of the Japanese MittenCrab Eriocheir japonicus DE HAAN in the Marine Environment

Abstract

The habitat, period of occurrence and behavior of Eriocheir japonicus in the sea was described. E. japonicus was collected from various types of sea bottom. The period when E. japonicus appeared in the sea (early September to early July) overlapped with that of small-size brachyurans but for a shorter period with larger migratory brachyurans. E. japonicus was observed not to dig burrows, but to bury itself in the sand or hide under rocks. Many males were collected while wandering, whereas many females were collected while hiding under rocks. Attached organisms (mainly green algae) on the exoskeleton were found more frequently on males than on females, suggesting that males are more active on the bottom than females.