Bering Sea | Fishes and Fish Habitats
Drivers of bitter crab syndrome in eastern Bering Sea snow and Tanner crab Presenter: Erin Fedewa , erin.fedewa@noaa.gov, Alaska Fisheries Science Center, NOAA Fisheries Mike Litzow , mike.litzow@noaa.gov, Alaska Fisheries Science Center, NOAA Fisheries Leah Zacher , leah.zacher@noaa.gov, NOAA - Alaska Fisheries Science Center Chris Long , chris.long@noaa.gov, NOAA Alaska Fishery Science Center Stan Kotwicki , stan.kotwicki@noaa.gov, NOAA Michael Malick , michael.malick@noaa.gov, Northwest Fisheries Science Center, NOAA Fisheries
Pam Jensen , pamjensen58@gmail.com Christie Lang , christie.lang@noaa.gov
Warming oceans are expected to increase the frequency and intensity of disease outbreaks like bitter crab syndrome, a fatal disease of crustaceans caused by a parasitic dinoflagellate Hematodinium sp . Visually diagnosed prevalence of bitter crab syndrome (BCS) in the eastern Bering Sea reached all-time highs in immature snow crab prior to the 2021 population collapse, however, this gross assessment method is insensitive and likely underestimates true population prevalence. Index sites were developed in 2014 to monitor Hematodinium sp . infection in Tanner and snow crab on the annual NOAA eastern Bering Sea bottom trawl survey using species-specific PCR assays. Here, we quantify Hematodinium prevalence in Tanner and snow crab across eastern Bering Sea monitoring sites (2015-2017), and investigate the potential role of endogenous and exogenous factors in driving BCS occurrence. Across all eastern Bering Sea monitoring sites, Hematodinium prevalence in Tanner crab increased each year from 21.1% in 2015 to 42% in 2017. Likewise, overall prevalence in snow crab increased from 11.5% in 2015 to 35.9% in 2017. Bayesian logistic regression modeling results indicated that while temperature effects on Hematodinium infection probability were weak, crab size and the seasonal progression of sampling appear to be the most important drivers in the probability of infection in both Tanner and snow crab. Additionally, we highlight preliminary findings from a pilot laboratory study to examine the effects of Hematodinium infection on snow crab survival, and discuss future studies aimed at better understanding the potential role of BCS on recent snow crab population declines.
Alaska Marine Science Symposium 2023 45
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