Identifying highly used Dungeness crab fleet fishing areas off central and northern California to inform entanglement risks of large whales
- Foraging
- Entanglement
Abstract
Large whales seasonally aggregate into highly productive areas to feed, which often overlap with regions popular for various fishing activities. This spatial and temporal overlap can lead to whale entanglements in fishing gear. Along the California coast, such impacts have been amplified by intense marine heat waves and climate-driven shifts in whale migration and habitat use, resulting in unprecedented reports of entangled whales and substantial disruptions to the region’s valuable Dungeness crab fishery. In response, the Risk Assessment and Mitigation Program (RAMP) was established to reduce entanglement risk through collaboration and adaptive management. As part of this program, we sought to quantify the spatial footprint of crabbing effort in California waters. To achieve this, we analyzed solar logger positional data collected from a sample of commercial crabbing vessels in Central and Northern California, applying movement models adapted from animal behavior studies to identify where crabbing occurred. We then fitted resource selection functions using environmental and operational variables predicted to influence crab fishing behavior, producing a spatial surface of crabbing probability. This information on the timing and location of crabbing activity enhances our understanding of fishing effort distribution and enables managers to implement targeted strategies that, when combined with whale distribution data, may reduce entanglement risk while maintaining optimal crabbing opportunities.
Johns, M., George, K., Lane, R., & Jahncke, J. (2026). Identifying highly used Dungeness crab fleet fishing areas off central and northern California to inform entanglement risks of large whales. California Fish and Wildlife Journal, (112), e5. https://doi.org/10.51492/cfwj.112.5
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{"image":"\/People\/Portrait\/kathi-george.jpg","alt":"Kathi George","title":"Kathi George","text":"Director of Cetacean Conservation Biology","link_url":"https:\/\/www.marinemammalcenter.org\/person\/kathi-george","link_text":"Read Bio"}
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