Feed comparison and feeding ecology in five sympatric teleost species of the northern Oman Sea

Investigating the relations and mechanisms of coexistence among sympatric species is essential to comprehend their ecological roles in the food webs. In the present study, the diet and trophic interactions of 5 abundant teleost species coexisting in the northern Oman Sea were examined using stomach contents analyses. The cumulative prey curves showed that the sample size of each studied species was large enough to clarify the general dietary preferences. The vacuity indices of Netuma thalassina, Plicofollis dussumieri and Otolithes ruber were less than 50%, indicating the comparatively gluttonous behavior of these species, while the estimated vacuity indices of Lutjanus johnii and Carangoides malabaricus were more than 50%. Assessment of %IRI (index of relative importance) revealed that diets of N. thalassina, O. ruber and C. malabaricus were similar and consisted mostly of teleost fishes followed by crustaceans. Conversely, P dussumieri and L. johnii mostly fed on crustaceans followed by teleost fishes. Results showed that P. dussumieri and L. johnii occupied an intermediate trophic level, whereas N. thalassina, O. ruber and C. malabaricus occupied high trophic levels, placing them as top predators in the food web. In total, analyses indicated that there were no significant differences in diets between these 5 teleost species.