1. Department of Zoology, Faculty of Science, Charles University, Vinicna 7, 12844 Prague, Czech Republic
2. Faculty of Fisheries and Protection of Waters, South Bohemian Research Center of Aquaculture and Biodiversity of Hydrocenoses, Research Institute of Fish Culture and Hydrobiology, University of South Bohemia in České Budějovice, Zátiší 728/II, 389 25 Vodňany, Czech Republic
3. Department of Management of Fisheries and Aquatic Ecosystems, University of Douala, Douala P.O. Box 7236, Cameroon
4. Department of Biological Sciences, University of Ngaoundéré, Ngaoundéré P.O. Box 454, Cameroon