A combined Gadget/FLR model for management strategy evaluations of the Barents Sea fisheries

A biologically sensible age–length structured multispecies Gadget model (incorporating minke whales, cod, herring, and capelin) forthe Barents Sea—acting as the operating model—has been linked to Fisheries Library in R—acting as the management procedure—toperform management strategy evaluations. Assessments may be run using either XSA, survey-based methods, or by taking modelledstock numbers directly. Total allowable catches are based on the assessment and harvest control rules (HCRs). The tool can be used forassessing a wide variety of sources of uncertainties within the assessment process. Model structure and linkages are described and a fitto the historical data is presented. A base case of future dynamic (non-steady state) stock trends, based on the existing HCRs, is com-pared with alternative management and environmental scenarios. The relative differences for each scenario in terms of stock size andcatches highlight a number of uncertainties within the biological and fisheries system. The results indicate that the current manage-ment rules are robust to the range of scenarios examined so far.