Fisheries assessment and management: a synthesis of common approaches with special reference to deepwater and data-poor stocks

Deepwater fish populations are often characterized by their life-history as being highly susceptible to overexploitation. Moreover, dependent fisheries often develop rapidly, so overexploitation may occur before resource dynamics are quantified sufficiently to assess safe biological limits. It is therefore crucial to employ assessment methods that make the best use of limited data and management procedures that account for large uncertainties. This review provides a critical synthesis of assessment and management approaches for deepwater fisheries. Given limitations in the data, it is clear that assessments are likely to benefit from the application of derived relationships between life-history characteristics and the sharing of this and other information across stocks. It is important that uncertainty in assessment results is represented adequately, and management methods must in turn ensure that decision mechanisms are robust to an incomplete picture of resource dynamics. This requires construction and testing of harvest control rules within a simulation framework. Harvest control rules themselves, however, need not be complicated, and simple empirical approaches can be adequate for situations in which only relative changes in biomass can be discerned from the data. Development and testing of these control rules is likely to prove a productive area of future research.