A PRELIMINARY SURVEY OF ESTUARIES ON THE SOUTH-WEST COAST OF SOUTH AFRICA, CAPE HANGKLIP—CAPE AGULHAS, WITH PARTICULAR REFERENCE TO THE FISH FAUNA

SUMMARY

The estuaries of the south-west coast of South Africa from Cape Hangklip to Cape Agulhas were surveyed during the period September 1994. The ichthyofaunal and physico-chemical characteristics of each system are presented and their suitability as estuarine nursery areas is discussed. Eight systems drain this area and, apart from a small coastal stream which does not appear to have any estuarine characteristics, range from estuaries which are permanently open to small and large systems which occasionally open to the sea. All these systems have variable temperatures, salinities, water levels and water currents which are linked to the seasonal nature of rainfall and runoff in the region. The fish fauna of the estuaries in this region were dominated by estuarine and estuarine-dependent marine taxa. The dominant estuarine species were Atherina breviceps, Gilchristella aestuaria and Psammogobius knysnaensis while important estuarine-dependent marine fishes included Liza richardsonii, Mugil cephalus and Galeichthys feliceps. Despite their great variability, the reproductive strategies of estuarine and estuarine-dependent marine fishes enable these species to utilise these estuaries as nursery areas.