Feeding ecology and dietary comparisons among three stingrays (Elasmobranchii; Dasyatidae) in the Iranian waters of Gulf of Oman and Strait of Hormoz

The aims of the current study were feeding ecology, trophic interactions and trophic level estimation of three stingrays (Elasmobranchii; Dasyatidae) including Himantura imbricata, H. randalli and Pastinachus sephen in the Oman Sea. A total of 191 individuals belonging to three species were obtained and studied using VI, %FO, index of relative importance (%IRI), trophic level analysis and Pianka index. Results showed that H. imbricata had very specialized diet, consuming mainly on Crustacean. While H. randalli had moderate niche breadth and crustaceans, followed by polychaeta were the most important prey category in its stomach contents. Finally, P. sephen had the greatest niche breadth, with a varied diet divided among items such as Bivalve, Echinodermata and Polychaeta. An analysis of similarity showed significant differences among three species in their diet, indicating a partitioning of food resources between them. It also represented the minimum of food competition between the three species, facilitating coexistence within a habitat. The trophic levels of the stingrays are less than 4, a position shared them as intermediate food webs.