ABSTRACT
This study was carried out to fill a knowledge gap and provide useful information for fish management and conservation in the Malilangwe reservoir. Length–weight relationships and condition factors (K) of six fish species, Oreochromis macrochir, Oreochromis mossambicus, Hydrocynus vittatus, Clarias gariepinus, Oreochromis placidus and Labeo altivelis, were investigated in Malilangwe reservoir, Zimbabwe between February and October 2011. Samples were collected monthly with seine and gill nets during three seasons: hot-wet (February to April), cool-dry (May to August) and hot-dry (September to October). The length–weight relationship had a significant positive correlation (r>0.5) for the six species. The growth exponent (b) indicated a negative allometric growth for seven species (b range = 1.52–2.81). Condition factor (K) values were greater than one (1.34–9.29) for O. macrochir, O. mossambicus, C. gariepinus, O. placidus and L. altivelis while it was less than one for H. vittatus (0.82–3.09). The value of K varied with seasons. The study provides new information on length–weight parameters for O. mossambicus and O. placidus.
ACKNOWLEDGEMENTS
German Academic Exchange Services (DAAD - A/10/02914) and the Malilangwe Trust Postgraduate Research Grant supported this study. We were assisted in the field by Lenin Dzibakwe Chari, Patrick Mutizamhepo and Clemence Chakuya from the University of Zimbabwe and Philemon Chivambu, Pandeni Chitimela and Pamushana, guides from the Malilangwe Wildlife Reserve. Elizabeth Munyoro and the technical staff of the Department of Biological Sciences, University of Zimbabwe, provided technical support.