Tangled Up and Blue: Evaluating Alternatives to Reduce Whale Entanglements in Commercial Dungeness Crab Fishing Gear

Abstract

Since 2014, the U.S. West Coast has experienced a sudden increase in reported whale entanglements with commercial fishing gear. The increase has been particularly acute in reported entanglements between Humpback whales (Megaptera novaeangliae) and commercial Dungeness crab gear. The current rate of entanglements is alarming and could trigger consequences for the responsible fisheries under the Marine Mammal Protection Act (MMPA) and Endangered Species Act (ESA); it seems likely that some change in the social-ecological status quo will be necessary to avoid significant harm to either the fishing community or the whales. Here, I compare several gear modifications and management alternatives to reduce entanglements, thereby reducing conflicts between whales and fishermen, scoring policy alternatives according to estimated cost to fishermen, likelihood of the alternative to reduce whale entanglements, and anticipated reaction of fishermen in response to the change. The intent of this study was to create a decision-aid tool for managers and policy makers to use when contemplating changes to the West Coast commercial Dungeness fishery. A small number of policy options consistently ranked high in a multi-criteria decision analysis; these included the use of Galvanic Timed Releases, which minimize the time that crab-pot lines are in the water and thus reduce the likelihood of entanglement. In addition, I include potential regulatory and non-regulatory pathways for implementing changes to the commercial Dungeness fishery, thereby providing both a substantive and procedural roadmap for reducing fishery-whale conflict.