Post-impoundment study of the fish communities of Tugwi-Mukosi Reservoir, Zimbabwe

Abstract

A post-impoundment ichthyofaunal survey was carried out in 2017 in Tugwi-Mukosi Reservoir using gill nets, seine net and fyke nets. The objective was to determine the present fish assemblages after impoundment of the reservoir in order to provide a baseline study that could be used to inform management decisions and for comparison with future predicted ecological changes associated with fishery development. The fish community composition was fairly diverse, comprising of 11 species belonging to four families, including Cichlidae (Oreochromis mossambicus; Coptodon rendalli; Tilapia sparmanii), Momyridae (Marcusenius macrolepidotus), Cyprinidae (Labeo cylindricus; Enteromius paludinosus; E. afrohamiltoni; E. topinni; E. trimaculatus; Engraulicypris brevianalis) and Clariidae (Clarias gariepinus). Oreochromis mossambicus was present at all sampled sites, with only two species (O. mossambicus; M. macrolepidotus) sampled downstream of the reservoir. Twenty-two prey/forage categories were observed in the guts of analysed fish, with macrophytes having the highest frequency of occurrence (90%). All the body condition values of fish from the reservoir exceeded one, and the estimated fish yield is 33.34 t/year. Collective efforts involving various stakeholders should be made to ensure the reservoir develops into a successful fishery resource, while also serving other purposes.