Evaluating fishery management strategies using an ecosystem model as an operating model

Management Strategy Evaluation (MSE) is an effective tool to gauge the relative performance of fishery management options. For the most part, MSEs have been applied to single-species management procedures. However, to be more inclusive of all the biological and technical interactions occurring within a system, ecosystem-based strategies are emerging. In order to test the feasibility of these strategies, a full ecosystem model should be used as an operating model. Mass balance food web models include many features that managers are interested in and therefore can be useful as an operating model. Until recently, full feedback interactions between a management strategy and a mass balance operating model were impractical. However, with the development of Rpath, users now have the ability to fully customize their mass balance models. We developed new functionality for the Rpath modelling framework that allows it to be used as a flexible operating model. Using an example Georges Bank model, we demonstrate how Rpath can now pause the simulation, evaluate an external model, and use the results to modify the parameters of the operating model. This new flexibility will allow users to test a variety of management strategies or couple to other models making Rpath a valuable tool for conducting MSEs.