The distribution of the freshwater cichlid Sarotherodon mossambicus in estuarine systems

Synopsis The distribution of Sarotherodon mossambicus in south east African estuaries is reviewed. It occurs commonly in closed estuaries and coastal lakes but is absent from open tidal estuaries. When a closed estuary opens to the sea the species usually retreats to the upper reaches. It is euryhaline and eurythermal and can feed on a wide variety of foods but experiments indicate that S. mossambicus avoids areas where current speeds exceed 370 m h^–1. It is concluded that the distribution of S. mossambicus in estuarine systems is governed by an interplay of the following factors: salinity stability, water currents, suitable breeding sites, presence of marginal vegetation, marine competitors and marine piscivorous fish.