Feeding strategy analysis of blue swimming crab (Portunus pelagicus, Linnaeus, 1758) using Castello's graphical model in Khuzestan coastal water

Feeding strategy of blue swimming crab (Portunus pelagicus) was investigated monthly in Khuzestan province water from April-2016 to march-2017. Samples were catch by trawl net. The content of P. pelagicus stomachs, percentage of occurrence frequency and Frequency percentage of feeding items was checked. In crab stomachs different feeding items group such as crustacean, mollusks, sponges, phytoplanktons, corals, fish, sand particles and etc. Was observed. The highest frequency of occurrence belonging to sponges, crustaceans and mollusks, respectively. Furthermore, Frequency percentage of sponges (38.65%) was higher than other preys. Costello's graphical model analysis Results analysis of P. pelagicus stomach content by Costello's model showed that this crab is a predator with specific feeding nich and feeding specific prey include sponges, crustacean and mollusks during a year. Though, it's feeding pattern show few seasonally fluctuations. In this model, phytoplanktons, fish, polycheats, corals, nematode, protista, ctenophore, nematodes, cestod, sea insects and sand identified as accidental or rare prey. Probably, ingest by crab while feeding from specific prey.