Ecosystem monitoring in the development of sustainable fisheries in Lake Tanganyika

Ecological, socio-economical, and institutional elements were combined when the Lake Tanganyika Framework Fisheries Management Plan was designed as the outcome of the FAO/Finland Lake Tanganyika Research Project in 1992–1999. The scientific synthesis provided a physical and limnological reference for understanding the biological productivity of the Lake Tanganyika pelagic ecosystem. Socio-economic surveys and community referenda were conducted to introduce and evaluate the proposed management measures amongst fishers, fish processors, and traders. During the transitional period prior to the implementation phase of the Fisheries Management Plan, an ecosystem approach in its simplest form is being utilized in monitoring the lake and fishery. Key parameters in meteorology and water movements are followed to assess the physical forces affecting upwelling, vertical mixing, and flow regimes of the pelagic ecosystem. Basic limnology, zooplankton community, and fish biology are studied to complement the time series of earlier project data. The long-term monitoring helps to identify which changes are caused by, for example, global climate change, and which ones may be owing to the fishery or other human activities. Some correlation occurs between the seasonal development of catch per unit effort of Stolothrissa tanganicae and copepod biomass. Sound data collection, timely conclusions, and appropriate reporting are essential for the decision-making in regard to management measures and applying the precautionary approach of FAO Code of Conduct for Responsible Fisheries. Strong personnel commitment and close links to the local fishery community are needed to supply the local development attempts with valuable scientific advice. In Tanganyika the institutional sustainability is required to harmonise legal arrangements and establish regional organization. The project results show the lake fisheries are best managed for the whole lake rather than separately by each country.