Feeding habits of an exotic species, the Mediterranean green crab Carcinus aestuarii, in Tokyo Bay

Abstract

Feeding habits of an exotic species, the Mediterranean green crab Carcinus aestuarii, in Tokyo Bay, Japan, were studied based on the analysis of stomach contents. Monthly samples were taken from May 2000 to October 2001 at stations near the Keihin Canal along the northern shore of Tokyo Bay. Stomach contents of 367 crabs (male n = 200, female n = 167) were examined. Carapace width ranged from 18.50 mm to 60.67 mm. Eleven food categories were identified: Bivalvia (mostly Mytilus galloprovincialis), other Mollusca, Cirripedia, Amphipoda, Brachyura, other Crustacea, Polychaeta, Pisces, unidentified animal materials, plant materials, and unidentified materials. The results showed that C. aestuarii is an omnivorous predator and that its diet depends greatly upon the availability of local prey species, especially in intertidal areas. Moreover, the analysis found no significant differences in the feeding habits of crabs of different sizes or sexes.