Food and feeding of <i>Portunus (Portunus) sanguinolentus</i> (Herbst) and <i>Portunus (Portunus) pelagicus</i> (Linnaeus) (Brachyura: Portunidae) along Karnataka coast

Abstract

The diet of Portunus (Portunus) sanguinolentus and P.(P.) pelagicus mainly consisted of crustaceans, fishes, molluscs, large quantity of unidentified matter and debris. Quantitative analysis of the gut contents revealed that crustaceans contributed to 47.1 % and 42.6 %, fish remains 29.0 % and 20.4 %, molluscs 5.7 % and 20.0 %, detritus 4.9 % and 4.7 % respectively of the gut content by volume in both species respectively. The study indicated that these crabs are primarily predators of sessile and slow moving benthic macro invertebrates. P.(P.) pelagicus had a strong preference for bivalves as food. The presence of detritus and unidentified items in the stomachs examined suggested that these crabs are detrivorous consuming fresh and decaying flesh of all kinds. The sexwise, sizewise and seasonal variability of diet in these crabs may be largely due to relative abundance of prey species in the habitat or related to change in cheliped strength and foraging behaviour.