1. Department of Fisheries and Water Resources, School of Natural Resources, University of Energy and Natural Resources, Sunyani, Ghana
2. Department of Theoretical and Applied Biology, Kwame Nkrumah University of Science and Technology (KNUST), Kumasi, Ghana
3. Department of Biology, University of Waterloo, Waterloo, Ontario, Canada
4. Biology Department and Large Lakes Observatory, University of Minnesota-Duluth, Duluth MN 55812, USA.