Sciences marines : recherche et développement

Abstrait

Feeding Ecology and Prey Preference of Grey Mullet, Mugil cephalus (Linnaeus, 1758) in Extensive Brackish Water Farming System

Asish Mondal, Deepta Chakravortty, Susmita Mandal, Bhattacharyya SB and Abhijit Mitra

Feeding ecology and prey preference of Mugil cephalus reared in extensive brackish water farming system was studied based on monthly examination of stomach contents over a period of 10 months (February-November, 2014). Feeding intensity, planktonic constituents in water and food constituents in the stomach were estimated numerically. The percentage compositions of food items in the stomach falling under different groups were then compared with that of fish pond to evaluate prey preferences. Lower feeding intensity was observed during the initial months which gradually increased as the fish’s grew. The dominant phytoplankton groups in pond water according to the order of dominance were Chlorophyceae, Bacillariophyceae and Myxophyceae. Most abundant zooplankton group was Dinoflagellates followed by Copepods. The main phytoplankton groups found in the stomach according to the order of dominance were Bacillarophyceae, Chlorophyceae and Myxophyceae. Dominant zooplankton group in the stomachs were Dinoflagellets followed by copepods. Prey preference analysis revealed that M. Cephalus actively selected Bacillariophyceae as most preferred food material. Myxophyceae was also selected as second preference. Chlorophyceae was not at all selected and was probably swallowed mechanically during intake of other food stuffs. True positive selection of copepods during initial months of rearing indicates preference by M. cephalus juveniles.