Authored by Brad Czerniak

Over 800 million people are malnourished and the global population is growing, and at the current trend 9 out of 10 children living in poverty in 2030 will be from Sub-Saharan Africa. The Sustainable Development Goal (SDG) Zero hunger and the SDG Life below water'promote the conservation and sustainable use of aquatic resources for sustainable development. The FAO emphasizes that we must meet the huge challenge of feeding our planet while safeguarding its natural resources , and that fish are a vital source of protein and essential nutrients, especially for many poorer members of our global community. The Conservation of Biological Diversity (CBD) states that a key feature of the ecosystem approach includes conservation of ecosystem structure and functioning . The uniform fish community pattern in aquatic ecosystems is that productivity decreases with body size, which means that more biomass is available from exploitation of small fish than from big fish. Thus meeting the food challenge and the ecosystem approach to fisheries is hindered by widely used, minimum size regulations in fisheries, driven by markets for big fish in the developed world. This research project shows theoretically and empirically that small-scale fisheries, operating without such regulations, would end up catching both small and large fish in proportion to their productivities. This corresponds to balanced harvesting and gives greater biomass yields with less ecosystem disruption than conventional management. These benefits are evident in a small-scale African fishery compared with a major European commercial fishery. Despite its potential benefits, balanced harvesting has been criticized as impractical from a management perspective. The results here show that balanced harvesting is actually the emergent outcome of allowing individual fishers to choose what size fish to catch. This has important implications for the establishment of co-management in African lakes.