The Cichlid Fishes of Lake Malawi, Africa

Abstract of Publication

Nsiku, E. 2002. Exploration of management and conservation strategies for the multispecies fisheries of Lake Malawi using an ecosystem modelling approach. University of British Columbia Fisheries Centre Research Reports 10 (2): 54-67.  

Lake Malawi, one the African Great Lakes, is the most species-rich freshwater body in the world. Conservation of the lake is thus one of the important areas that needs to be focused by the riparian countries bordering it as well as the scientific community and international funding agencies. The lake's ecosystem and fish resources, which are some of the important factors in the implementation of conservation initiatives, are analyzed through construction of an Ecopath model. Application of Ecosim routine follows in order to optimize policy, particularly of fisheries, in the objectives of maximizing fisheries rent, social benefits, rebuilding of mandated species and ecosystem structure or health. Trophic interrelationships in the functional groups, which include the main fish species caught, and trophic structure of the lake are assessed. Twenty-six functional groups are quantified. Chaoborus edulis, Engraulicypris sardella larvae and the predatory zooplankton, Mesocyclops aequatorialis aequatorialis; form the main pathway through which energy flows from bottom to top trophic levels in the Lake Malawi ecosystem. The trophic structure of the lake system deteriorates over time. Maturity of the lake ecosystem is in the middle stages. Standing biomass and production rates, i.e. model control regimes, are dependent more on food availability rather than impact of predation The model supports observations of overexploitation in most fish resources that form the main fisheries in Lake Malawi. This includes even offshore species, especially those that are also exploited by traditional fisheries such as kampango. The traditional fisheries sector contributes more than the commercial sector to the influence fisheries has on the ecosystem of the lake. The analysis optimizes the exploitation and conservation goals for the ecosystem and fish resources of Lake Malawi at reduced fishing effort and catch from the current levels.




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