Diet of yellowfin and skipjack tunas in the eastern Arabian Sea

Diet composition, feeding strategies and predator-prey relationships of yellowfin Thunnus albacares (Bonnaterre, 1788) and skipjack Katsuwonus pelamis (Linnaeus, 1758) tunas in the western Indian Exclusive Economic Zone (eastern Arabian Sea) were studied by stomach content analysis. Stomachs of 406 yellowfin tuna specimens in the fork length range of 48 to 165.5 cm caught during exploratory longlining conducted in the eastern Arabian Sea were examined, of which, 15.52% were empty. Purple back flying squid (Sthenoteuthis oualaniensis) was the dominant prey species, followed by the swimming crab (Charybdis smithii), bigeyecigarfish (Cubiceps pauciradiatus) and flyingfishes (family Exocoetidae). Diet breadth index and the Tokeshi graphical analysis showed dominance of few prey species which are available in high densities in the Arabian Sea, indicating opportunistic feeding nature of this apex predator. A total number of 72 skipjack stomachs were studied, of which, 22.22% were empty. Purple back flying squid was the dominant food item, followed by the flyingfish.