Protected area concept effect on species composition and abundance: a case of Lake Mutirikwi, Zimbabwe

Abstract

A study to investigate the concept of protected areas in the conservation of targeted fish species was carried out on Lake Mutirikwi, Zimbabwe. The research was aimed at establishing differences in fish species composition, abundance and catch per unit effort (CPUE) on different sites of the lake and to enhance conservation and management of targeted fish species through better understanding on the concept of protected area. The study was done using a Completely Randomised Design (CRD) with two treatments and no blocking factor. Biological data (species, count and weight) for individual fish samples were collected from two sampling stations, one protected and the other fished using monofilament gillnets. Species composition, species diversity (H'), species evenness and CPUE were determined in each station. A total of 1310 specimens belonging to 7 species (Tilapia rendalli, Oreochromis niloticus, Oreochromis macrochir, Serranochromis robustus, Micropterus salmoides, Clarius gariepinus, and Mormyrus longirostris) representing 4 families (Cichlidae, Centrachidae, Clariidae, and Mormyridae) were recorded in the 10 sampled stations. All statistical analysis was performed with GenStat Version 14 software. The findings reviewed no significant difference in fish species composition (F = 0.581; p > 0.05), a significant difference in fish abundance (F = 0.018; p < 0.05); in terms of biomass (F = 0.019; p < 0.05) and catch per unit effort (CPUE) (F = 0.019; p < 0.05) between the protected areas and fished areas. The results add to a growing body of evidence that, populations of commercially exploited fish species can rise considerably within protected areas given time and adequate protection. It is therefore strongly recommended that the Zimbabwe Parks and Wildlife Management Authority is to put in place strong law enforcement and stiff penalties to minimise poaching activities and zone encroachment within the protected areas and also to establish closed fishing seasons, regular monitoring of mesh sizes, and prohibiting fishing activities in littoral zones so as to realise the value of protected areas.