Relation of size and sex to the natural diet of the red crab Charybdis feriatus Linnaeus (Brachyura: Portunidae) from Pilar-Capiz Bays, Northern Panay

Abstract

A total of 395 (males= 282; females=113) specimens of the red crab Charybdis feriatus were collected from Pilar-Capiz Bays from January-December 2002 and were used for the present study. Relative fullness index were computed for both sexes of different size classes. Results showed that stomachs of females were slightly fuller than that of males. Similar observation was made between juvenile and adult specimens. A total of 75 (males= 57; females= 18) gut contents were analyzed in detail. Major food items in the diet of the crabs include unidentified matter, unidentified eggs, fish, crab, and shrimp remains. Frequency of occurrence and combined visual estimation of unidentified organic matter were used for the examination. No dietary differences due to ontogenetic change were observed in the species while diet of male crabs were found to be more varied than those of females. However, frequency of occurrence of major food items in the stomachs of both sexes was comparable.