Design of operational management strategies for achieving fishery ecosystem objectives

Ecosystem objectives in fisheries management usually flow from high-level nationalpolicies or strategies and international agreements. Consequently they are oftenbroadly stated and hence are difficult to incorporate directly in management plans.Predicting the results of any management action is very uncertain because thedynamics of ecosystems are complex and poorly understood. Methods to design andevaluate operational management strategies have advanced considerably in the pastdecade. These management-strategy-evaluation (MSE) methods rely on simulationtesting of the whole management process using performance measures derived fromoperational objectives. The MSE approach involves selecting (operational) managementobjectives, specifying performance measures, specifying alternative managementstrategies, and evaluating these using simulation. The MSE framework emphasizes theidentification and modelling of uncertainties, and propagates these through to theireffects on the performance measures. The framework is outlined and illustrated bythree ecosystem-related applications: management of benthic habitats and broad fishcommunity composition; by-catch of species of high conservation value; and foodchaininteractions and dependencies. Challenges to be overcome before broaderecosystem-related objectives can be fully handled are discussed briefly.