Journal of the Marine Biological Association of the UK

Research Article

Diet composition and food habits of Caranx rhonchus (Carangidae) from the Gulf of Gabes (central Mediterranean)

Ayda Sleya1 c1, Othman Jarbouia2, Mohamed Ghorbela2 and Abderrahmen Bouaina1

a1 Faculté des Sciences de Sfax, BP 802–3018 Sfax, Tunisie

a2 Institut National des Sciences et Technologies de la Mer (Centre de Sfax), BP 1035–3018, Sfax, Tunisie

Abstract

From June 2004 to May 2006, 1040 Caranx rhonchus (Carangidae) ranging from 6.5 to 30.6 cm in total length (TL), fished in the Gulf of Gabes (south Tunisia, central Mediterranean), were used to investigate feeding habits of the species. This study was based mainly on the evolution of the index of relative importance (IRI) with respect to sex, fish size and season. Among 1040 stomachs examined, 595 were empty (%VI = 57.2). The vacuity index (%VI) differed significantly across months and declined slightly with season. A total of 13 species representing 12 different families belonging to four major groups: teleosts, crustaceans, molluscs and annelids, were identified in stomach contents of Caranx rhonchus.

Caranx rhonchus is primarily an opportunistic piscivorous fish with a diet characterized by a wide range of species. Teleosts occurred in the majority of stomachs, with a total of the relative importance (%IRI) of 52.7%. The anchovy Engraulis encrasicolus were the most important teleost species (%IRI = 11.2), while crustaceans were the second most important food category consumed (47.1%).

There were no significant differences in the diet between males and females, but significant differences were found with season and among size-classes.

(Received September 04 2007)

(Accepted January 30 2008)

Correspondence:

c1 Correspondence should be addressed to: Ayda Sley Faculté des Sciences de Sfax BP 802–3018 Sfax, Tunisie email: sley_aida@yahoo.fr