Freshwater Fish Abundance and Distribution in the Orange River, South Africa

Abstract

Fish species abrmdance and distribution in the middle and lower Orange river basin were investigated in November 2010. Fish specimens were collected by means of an electric shocker and seine nets. Sixteen fish species comprising of a total mnnber of 13,7 62 individuals belonging to five families were collected. The nwnber of individuals caught showed that 64.7% were represented by the family Cyprinidae, 34.1% Cichlidae, 0.25% Claridae, 0.67% Austroglanidae and 0.36% Poecilidae. Aliens Cyprinus carpio, Gambusia affinis and translocated Oreochromis mossambicus were also recorded during the study. Labeo capensis, Labeobarbus aeneus and Pseudocrilabrus philander were the most abrmdant in the middle section of the river while Mesobola brevianalis and Barbus hospes were more abrmdant in the lower section of the river. During this study, a new distribution of Gambusa affinis was recorded at all sites except at site one and seven. High abrmdance of Austroglanis sclateri. was only recorded at site three.