Incorporating Ecosystem Dynamics in Fishery Stock Assessment and Management: Progress and Challenges Part 1

The fundamental goals of fisheries management are to prevent overfishing and optimize fishing opportunity over the long term. This long-term view infers that management measures should be responsive to fluctuations or shifts in any relevant ecosystem variables. Managers rely on stock assessments to estimate stock status and sustainable harvest levels.  However, most stock assessment models are constructed without calibrating to dynamics in the ecosystem and often assume that many essential parameters that determine stock dynamics are either stable or vary according to a random process. For many stocks, this stationarity assumption is challenged by dynamics such as climate change, ecosystem cycles, and regime shifts. Yet, while there are well-established connections between stock productivity and various ecosystem attributes, numerous studies have demonstrated that including ecosystem variables in the stock assessment often does not improve the ability to achieve management goals.  This presents a challenge to fishery management in determining how to account for major ecosystem oscillations, regime shifts, altered trophic structure, or climate change. The goal of this symposium is to stimulate discussion on how to best incorporate environmental information in the fishery management process so as to be responsive to major ecosystem shifts and fluctuations. The symposium will include theoretical papers demonstrating novel concepts, relevant case studies, as well as syntheses of techniques and lessons learned.