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This paper reviews the importance of African lakes and their management challenges. African inland lakes contribute significantly to food security, livelihoods and national economies through direct exploitation of fisheries, water resources for irrigation and hydropower generation. Because of these key contributions, the ecosystem services provided are under significant stress mainly owing to high demand by increasing populations, negative anthropogenic impacts on lake catchments and high levels of poverty which result in unsustainable use. Climate variability exacerbates the stress on these ecosystems. Current research findings show that the lakes cannot sustain further development activities on the scale seen over the past few decades. Millions of people are at risk of losing livelihoods through impacts on livestock and wildlife. The review further shows that the problems facing these lakes are beyond the purview of current management practices. A much better understanding of the interactions and feedbacks between different components of the lake socio-ecological systems is needed to address the complex challenges of managing these ecosystem services. This review suggests that the three small wetlands of Chad, Chilwa and Naivasha provide an opportunity for testing novel ideas that integrate sustainability of natural resource management with livelihoods in order to inform policy on how future land use and climatic variability will affect both food security and the ecosystem services associated with it.

This chapter presents an ex post impact assessment of the development and dissemination of small-scale integrated aquaculture-agriculture (IAA) technologies in Malawi over more than 15 years by the WorldFish Centre and its national and international partners. The results indicate that the adoption of IAA technology in Malawi has improved total farm productivity by 10%, increased per hectare farm income by 134% and total farm income by 61%, and improved the technical efficiency of farming by almost 40%. In addition, the increased per capita consumption of fresh fish by about 208% and per capita consumption of dried fish by about 21% have resulted in an enhanced consumption of protein-rich foods. IAA has improved the sustainability and environment of the adopters' farms, reduced nitrogen loss by half and improved nitrogen use efficiency. The development and dissemination of IAA technologies in Malawi have also institutionalized the natural resource management approach within the Malawi Department of Fisheries, strengthened local institutions and improved the overall welfare of both producers and consumers. The internal rate of return from research and dissemination of IAA technologies in Malawi is at least 12.2%. This estimated rate of return is a very conservative estimate and does not include many of the positive non-market benefits of IAA technology such as impact on ecosystem health and local institutions.

This study analyses land use and cover changes in the Likangala River catchment of Lake Chilwa, Malawi, an endorheic tropical African lake. It also examines how land use-related physico-chemical and hydrological parameters in two affluent rivers of the lake affect the migratory and reproductive behaviour of Barbus paludinosus and B. trimaculatus, which are migratory, ecologically and economically important fish species. Land use analysis indicated increasing deforestation and conversion of agricultural land to homestead development. High soil losses of 100t ha -1 yr -1 were estimated in the upper reaches of the catchment. High rainfall kinetic energy and poor vegetation cover were major determinants of soil loss. Sediment yield was high (374t km -2 yr -1 ) in the more degraded catchment of the Likangala River, compared to 315t km -2 yr -1 in the less degraded Domasi River catchment. A situation analysis for the Likangala River catchment showed that a marked reduction in soil loss occurred when a combined 20% increase of contour ridging, maize yield and tree canopy was assumed. Multiple regression analysis indicated that sediment yield, river flow rate, electrical conductivity and total suspended solids are significant predictors of the migration dynamics and reproductive status of both Barbus species. Our results suggest that the most critical soil loss factor should form an integral part of soil conservation measures in the catchment and that appropriate management actions that reduce fishing pressure on breeding Barbus females in the affluent rivers should be formulated to ensure the success of spawning migrations of breeding females into these rivers. The study further demonstrates how a combination of land use modelling, community outreach, river water quality analysis and fish population dynamics analysis can be used to identify factors useful for managing and monitoring the catchments of small tropical lakes.

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