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.