Uncertainty and Risk Evaluation in Stock Assessment Advice for U.S. Marine Fisheries

This paper describes some of the ways that the uncertainty in fisheries scientific advice has been communicated to managers for different fisheries in the United States in the past several years. Describing the uncertainty can be important in allowing managers to weigh the benefits and losses of different management strategies and to allay concerns about the effects of process, measurement, and model errors on the scientific advice, even if a formal decision theoretic risk analysis has not been carried out. The four general steps in analyzing uncertainty and assessing risk are estimation of the uncertainty in the assessment of current stock status due to measurement error, evaluation of the impacts of potential model errors on the assessment, stochastic projections incorporating estimation error and process errors to investigate the impacts of different management options, and assessment of risk using simple utility functions. At least one of these steps has been included in assessment analyses of about 20 major U.S. fisheries. All of these steps have been incorporated in the scientific advice on a few fisheries to date and should be attempted whenever possible to improve the information available to fishery managers.