Occurrence of fish larvae in the St Lucia Estuary, KwaZulu-Natal, South Africa

Abstract

Ichthyoplankton samples were collected over 12 consecutive months. at a fixed station 4 km upstream from the mouth of the St Lucia Estuary, in order to study the recruitment of fish larvae into the estuary. In all, 51 690 fish larvae, representing 44 families and 85 species, were collected. The Gobiidae and the Clupeidae were the two dominant families, representing 74 and 19% of the larvae respectively. The most abundant species were the river go by Glossogobius callidus and the estuarine round herring Gilchristella aestuaria, which contributed 67 and 19% respectively. The proportion of species which are dependent on estuaries to some degree contributed 54% of the total number of taxa. Environmental variables correlated with larval densities in each estuarine-association group and were species-specific. Turbidity and salinity accounted for 45% of the variation in larval densities in the estuarine-dependent group, where densities were greater at higher turbidities and lower salinities. Densities of larvae ...