Bering Sea | Fishes and Fish Habitats DOCTORATE ORAL PRESENTATION Size and density-dependent incidence of BCD suggests cod predation more important than fishery for disease control Presenter: Laurinne Balstad , lbalstad@ucdavis.edu Cody Szuwalski , cody.szuwalski@noaa.gov, Alaska Fisheries Science Center, NOAA Fisheries The unprecedented crash of the Eastern Bering Sea (EBS) snow crab ( Chionoecetes opilio ) population (2019-2022) coincided with multi-year increases in regional temperature and bitter crab disease (BCD, Hematodinium sp .) prevalence across the region. This has prompted numerous management suggestions, including increased fishing pressure (i.e., “fishing out”) to minimize BCD spread and BCD-induced mortality. Better understanding of disease ecology and environmental correlates of BCD allows managers to determine the appropriateness of such suggestions. Here, we identify environmental correlates of BCD using spatio-temporal species distribution modeling. Our results indicate higher BCD occurrence in smaller crabs, especially crabs below legal fishing size. This suggests that increased fishing pressure will not reduce BCD occurrence in the EBS. Additionally, we demonstrate that temperature and cod populations both impact BCD occurrence, pointing to potential avenues for future research to explore the combined effects disease, temperature, and predation on snow crab population dynamics. Better understanding the interaction of these effects can help determine when, or if, BCD plays a role in population dynamics of snow crab. Identifying factors that shape parasite distributions can help inform management policy levers that respond effectively to climate-mediated changes in parasite incidence, and minimize ecological and economic impact to marine fisheries.
Alaska Marine Science Symposium 2023 46
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