Temporal variation in the recruitment of larval fish into the Mhlathuze Estuary in northern KwaZulu-Natal, South Africa

Abstract

In total, 136 taxa of larval fishes representing at least 49 families were recorded in the Mhlathuze Estuary over one year. Community structure was very similar to that found in a similar study at the adjacent Richards Bay Harbour, with dominating families being the Engraulidae, Gobiidae, Sciaenidae and Clupeidae. Marine-spawned larvae dominated the catch, with the most dominant being euryhaline species that usually breed at sea and whose juveniles show varying degrees of dependence on estuaries. High recruitment (238 per 100 m³ and 308 per 100 m³) occurred during November 1998 and July 1999 respectively, these being the months of lowest river discharge. Results indicated that a physical variable, in this case river flow, is probably the forcing factor regulating spawning and recruitment.