S. Behzadi - Fisheries Department, Faculty of Marine Science and Technology, Hormozgan University, Bandar Abbas, Iran. P.O. Box; ۳۹۵۵
E. Kamrani - Fisheries Department, Faculty of Marine Science and Technology, Hormozgan University, Bandar Abbas, Iran. P.O. Box; ۳۹۵۵
F. Kaymaram - Iranian Fisheries Science Research Institute (IFSRI), Agricultural Research Education and Extension Organization (AREEO), P.O. Box: ۱۵۷۴۵/۱۳۳. Tehran, Iran.
M.Sh. Ranjbar - Department of Marine biology, Hormozgan University, Bandar Abbas, Iran. P.O.Box; ۳۹۵۵.

This study examined the ecological factors associated with feeding in Rachycentron canadum (cobia) in the waters of Persian Gulf and Oman Sea. Seasonally variation of stomach condition of cobia male, females, pooled and size wise were analyzed. In general, ۵۷۷ cobia were collected (۳۴۰ males, ۲۳۷ females) (۲۰–۱۶۱ cm Total length) from Sept. ۲۰۱۴ to Sept. ۲۰۱۵ by the Ferdows-۱ survey ship and from the landing areas in Bandar Abbas harbor seasonally. Our results provide the first estimates of trophic level (Tr.L) (۴.۳۲±۰.۷۶, mean±Se), consumption per biomass (Q/B) (۶.۱۳), and aspect ratio of the caudal fin (ARc.f) (۳.۱) for R. canadum in the Hormuzgan Province. We also found that bony fish made up more than ۸۰ percent of the relative importance of particular prey (IRI %), indicating R. canadum primarily preys on these species. The immature group (۲۰–۴۰ cm,T.L), tended to feed on Penaeidae family, small crabs, and mollusks. Hierarchical clustering revealed that the frequencies of different types of prey could be applied to categorize the length classes into three levels. The result of this study revealed that the immature group and the ۲۰-۴۰ cm length class tended to feed on Penaeidae family, crabs, and mollusks. Also, we found that males generally fed more than females in all seasons and that R. canadum had an average dietary intake. The findings of this study can be used to prepare a food formulation for cobia that resembles the native diet.

Rachycentron canadum, Feeding Ecology, Trophic level, Consumption per biomass Persian Gulf and Oman Sea