A preliminary investigation of winter daily food intake by four small teleost fish species from the Igoda Estuary, Eastern Cape, South Africa

Abstract

The winter diet and daily ration of four small size classes of estuary-associated fishes, Rhabdosargus holubi, Gilchristella aestuaria, Glossogobius callidus and Monodactylus falciformis, from the temporarily open/closed Igoda Estuary were investigated. The diet of G. callidus was dominated by gammarid amphipods and copepods. Copepods accounted for 70% by volume of the stomach contents of M. falciformis and 50% in G. aestuaria. Plant material and copepods were the most prominent food items in the stomach contents of R. holubi. All species except G. aestuaria showed a diel pattern in feeding activity. Gut evacuation rates ranged between 0.3 and 2.5 h^–1 for incubations, and from 0.1–0.4 h^–1 in situ. Daily ingestion rates, estimated using an in situ stomach content analysis technique, ranged between 4.0% and 10.2% body dry mass.

Keywords: fish diet, diel feeding pattern, daily ration, gut evacuation rate, estuaries

African Journal of Aquatic Science 2008, 33(1): 83–86