Optimizing effort allocation in data poor mixed fisheries

Management of mixed fisheries requires reconciling many different and often conflicting objectives (achieving MSY targets and ensuring economic viability among others). In multi-gear mixed fisheries, where many fleets exploit the same species, reallocation of fishing effort can optimize the biological and socioeconomic output of the fishery. Most existing effort allocation tools require extensive data for their parameterization (i.e. detailed effort data and/or analytical assessment of stock status). We present a low-data demanding effort allocation framework for fisheries managed through effort control, with minimum data requirements the surplus production assessment of key stock, catch shares and basic economic fleet data. Profit maximization is considered the overall management goal, which is constrained by single-species biological targets. The method is tested on the Aegean Sea demersal fishery, where two fleet segments exploit numerous species. To achieve sustainable exploitation for the main Aegean stocks, the total effort should be reduced by similar to 30%. The framework allows integrating various biological, economic, or other objectives and provides a simple graphical illustration of the allocation result, which can provide a useful tool to convey complex information to managers. To facilitate its application, the source code developed in R programming environment is provided as a supplement.