A preliminary survey of the estuaries on the southeast coast of South Africa, Cape Padrone – Great Fish River, with particular reference to the fish fauna

Abstract

ABSTRACT A basic ichthyofaunal and physico-chemical survey of 10 estuaries on the southeast coast of South Africa from Cape Padrone to the Great Fish River was conducted during October and November 1991. The greatest diversity of fishes was found in the freshwater-deprived but permanently open Kariega, Kowie and Bushmans estuaries and this can be attributed in part to the influence of clear, marine waters and the greater number of marine stragglers recorded. The number of species recorded in the freshwater-dominated Great Fish Estuary was lower but published information suggests that a higher fish biomass per unit area occurs in this system when compared to equivalent freshwater-deprived estuaries. Six systems (Boknes, Kasouga, Rufane, Riet, West Kleinemonde and East Kleinemonde) were temporarily open/closed estuaries and although supporting lower species diversity also provided important habitat for a number of estuarine associated species, particularly resident species, which were recorded in high numbers.