FORAGING STRATEGY OF THE MUDSKIPPER PERIOPHTHALMUS-SOBRINUS EGGERT INA KENYAN MANGROVE

The feeding behaviour of Periophthalmus sobrinus was studied in a popu lation living along the channels of the Tana river delta. In November 1993 mudskippers were sampled every 2 tidal h for two consecutive spri ng and neap tides both during the day and night. The fishes were sexed and their stomach contents analysed. The results indicated that the m udskipper has a carnivorous diet and forages during both day and night although feeding greatly decreases after dark. Quantitative and quali tative differences in diet were found during the day and night of the two synodic and tidal phases. These differences were also demonstrable in the two sexes. The study showed that females of P. sobrinus are mo re selective than males and that differences between the two sexes may be related to reproductive condition. Furthermore, the mudskippers sh owed a tidal rhythm in feeding behaviour with peaks of activity around low tide (LT) on spring tides and around high tide (HT) on neap tides . Foraging activity seems to be influenced by the different spatial an d temporal distributions of the mudskipper's prey caused by synodic, t idal and diel changes in the environment.