Post-filling phase ichthyofaunal community and fishery potential of Chitsuwa Reservoir, a small tropical reservoir in Zimbabwe

Abstract

Many small reservoirs exist throughout Southern Africa, and with adequate management have the potential to contribute significantly to food security. The fisheries and limnology of the newly created Chitsuwa Reservoir in Zimbabwe were studied with the objective of generating information to support the development, management and sustainable use of fisheries to enhance the socio-economic status of riparian communities. Based on gill nets of various mesh sizes, it was confirmed that the reservoir is presently inhabited by a fairly diverse fish community comprising ten species belonging to five families (Clarias gariepinus; Coptodon rendalli; Labeo cylindricus; Marcusenius macrolepidotus; Micropterus salmoides; Momyrus longirostris; Oreochromis mossambicus; Oreochromis niloticus; Serranochromis microcephalus; and Tilapia sparrmanii). Oreochromis niloticus dominated the reservoir with respect to both abundance, biomass and catch. The index of relative importance revealed O. niloticus and M. macrolepidotus were the most important species. Results from the Canonical Correspondence Analysis revealed a clear division of the fish species that followed the environmental variables. Although fisheries may benefit from the invasive M. salmoides and the established O. niloticus, their presence in the reservoir is a cause for concern for conserving native congeneric species that risk extirpation through documented mechanisms. The results of the present study suggest sound management of the reservoir is required to raise its potential of supporting the livelihoods of the surrounding communities with a predicted annual fish yield of 61.5 t/year. Management of this reservoir should involve the local communities, empowering them so that they practice sustainable non-destructive fishing methods.