The diet, food selectivity and niche of Rhabdosargus sarba (Teleostei: Sparidae) in Natal estuaries

Abstract

The juveniles and subadults of Rhabdosargus sarba are one of the most common components of the benthic fish community of Natal estuaries. The diet consists mainly of aquatic macrophytes and filamentous algae although a significant proportion is made up of bivalves and the amphipod Grandidierella lignorum. The last two taxa are positively selected when little plant material is consumed. R. sarba feeds during daylight with a peak in the early afternoon. The relationship between R. sarba and the very similar sympatric R. holubi and R. auriventris are discussed in relation to their diet, divergence and distribution. Resource partitioning in Natal estuaries between R. sarba, the Gerreidae and Pomadasys commersonii is also discussed.