Diet of the demersal feeding Leiognathus equula in the Mfolozi–Msunduzi estuarine system, South Africa, in response to an impoverished macrobenthic invertebrate community

Abstract

Leiognathus equula, a species generally regarded as a zoobenthic feeder, was the most abundant fish species sampled in the Mfolozi–Msunduzi estuarine system in 2008–2010, despite the zoobenthos in this system being impoverished. Four dietary assessment methods all confirmed that its diet, both spatially and temporally, was overwhelmingly dominated by the copepod Pseudodiaptomus stuhlmanni. Plankton data indicated the presence of high P. stuhlmanni densities supporting this fish species. It appears likely that L. equula are present in relatively large numbers due to their ability to target P. stuhlmanni, probably preying on them during daylight hours when these copepods are on or near the estuary bottom.