Feeding ecology of blue swimming crab, Portunus segnis (Forskal, 1775) in Coastal waters of Chabahar, (Oman Sea)

Feeding habits of the blue swimming crab, Portunus segnis were studied in the coastal waters of Chabahar (Oman Sea) during the period from January 2015 to June 2015. The stomach contents of 623 crabs (included 138 males and 125 females) were analyzed. Their contents appeared to consist of mainly large quantities fish (48.2 %), crustaceans (19 %) and molluscs (15.7 %), also small quantities of seagrass (3.3 %), mixed matter (8.8 %), unidentifiable matter (5 %) and debris. The C.V. index was 44.8 %, also the crabs in the warm season most voracious (CV=38.9 %) than in cold season (CV=51.1 %). The crabs without barnacle comparatively voracious with barnacle-carrying crabs (p<0.05). There was no difference observed in the quantity of the food consumed in both sexes and also significant differences observed in the preference for food items in the different size groups. Based on the major food items were observed in different size groups, the crustaceans, fish, and molluscs were the most dominant in juvenile crabs and the fish items were the most dominant (with 62 %) in adult and larger size groups crabs.