Stomach content and seasonal variation in diet composition of cobia, Rachycentron canadum in the Dungun coast, Malaysia

Aim: Analysis of food and feeding habit of cobia, R. canadum in Dungun coat, Malaysia was carried out in this research in order to provide information on their diet preference and feeding intensity of cobia in the area. Methodology: Monthly samples were collected from licensed commercial trawls in Dungun, Terengganu, Malaysia for food and feeding studies. Results: Out of 231 cobias examined between April 2014 and May 2015, 111 contained food in their stomach out of which 98 had at least one identifiable prey item. Analysis of gut content analysis showed that bony fish was consumed by cobia all the year round with Hilsa sp., Aiepes sp. and Carangides sp. being the most frequently encountered species. Bony fish was the dominant group in the diet with percentage index of relative important (% IRI) value of 72.27 %, while crustacean and mollusc contributed less with % IRI values of 2.98 % and 24.75 % respectively. Higher stomach fullness index (SFI) was recorded during April (2.88), June (2.06) and November (2.42) months, while SFI was lower in May (0.67) and August (0.86). The percentage of empty stomach (EC) was higher in October (80%), August (70%) and July (69%), respectively, intermediate in the remaining months as values were about 50 %. This stomach fullness index SFI and EC suggest moderate feeding intensity of cobia in the waters of Dungun. Interpretation: The dominance of squid by volume in April and July in cobia indicates the influence of habitat on their food preference, as seasonal availability of food items in the habitat may be a dictating factor. Fish dominated in diets of cobia for most of the months while crustaceans and molluscs can be regarded as occasional food. This study demonstrates that cobia in Dungun, Malaysia predominantly consumed bony fishes and squids.