An application of the composite risk assessment method in assessing fisheries stock status

The status of a fishery stock is often determined by comparing an indicator reference point (e.g., current fishing mortality) with a management reference point (e.g., F0.1). Both references are likely subject to large uncertainty. Thus, it is necessary to incorporate such uncertainties in determining the status of fisheries. The composite risk assessment method, which is commonly used in civil engineering, can be used to quantify uncertainty associated with both indicator and management references in evaluating the status of a fishery. Ignoring either part of the uncertainty may result in overexploitation in fisheries management. We applied this method to the Atlantic cod (Gadus morhua) fishery of eastern Newfoundland and Labrador. The results suggest that the uncertainties in both indicator and management reference points can influence the evaluation of the fishery stock status. Uncertainty can come from different sources and is difficult to quantify. We suggest conducting a sensitivity analysis to evaluate the relative importance of uncertainties resulting from different sources. Such an analysis will enable one to identify key factors influencing the assessment of stock status and management.