Maximizing fisheries yields while maintaining community structure

Under the Ecosystem Approach to Fisheries an optimal fishing pattern is one that gives the highest possible yield while causing the least structural impact on the community. Unregulated, open access African inland fisheries have been observed to sustain high catches by harvesting a broad spectrum of species and sizes, often in conflict with current management regulations in terms of mesh and gear regulations. Using a size and trait-based model we explore whether such exploitation patterns are commensurable with the Ecosystem Approach to Fisheries, by comparing the impacts on size spectrum slope and yield with the different size limit regimes employed in the Zambian and Zimbabwean side of man-made Lake Kariba. Long-term multispecies data under fished and unfished conditions are used to compare and validate the model results. Both model and observations show that the highest yields and low structural impact on the ecosystem are obtained by targeting small individuals in the community. These results call for a re-evaluation of the size based management regulations that are ubiquitous in most fisheries.The accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author