Rebuilding mixed stock fisheries: lessons from the U.S. West Coast

Abstract

Management of commercial fisheries is imperative to global food security, economies, and sustainability. However, common management frameworks are often challenged when species with differing sustainable exploitation rates are caught simultaneously in a mixed stock fishery. The tradeoffs which emerge are often magnified when overfished stocks are persistent in the system. As observed in the U.S. West Coast groundfish fishery, the priority to rebuild overfished stocks according to a strict timeline can result in forgone yield of abundant species and negative impacts on communities. In this thesis, I retrospectively analyzed alternative rebuilding scenarios for the West Coast to test if a management approach based on meeting fishing mortality targets could result in fewer tradeoffs for stakeholders while still meeting conservation objectives. I then developed a two-area single species age structure model to evaluate if marine closures can be used as an alternative management approach to single-species catch limits and provide adequate rebuilding protection while minimizing forgone yield of abundant stocks. The analyses on alternative management approaches described in this thesis can be applied to global fishery managers as they address similar challenges in their respective fisheries.