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The Pribilof Islands blue king crab ( Paralithodes platypus) fishery collapsed over two decades ago, is considered overfished, and has not recovered in the absence of fishing. Red king crab ( Paralithodes camtschaticus) abundance estimates have exceeded blue king crab for over three decades. We investigated the roles of larval recruitment and habitat availability as potential mechanisms limiting blue king crab recovery. We conducted young-of-year abundance and habitat assessments near Saint Paul Island from 2017 to 2019 and compared these results to 1983–1984 historical data to assess changes in larval supply and benthic substrates. Historically abundant blue king crab settlers were rarely encountered in our surveys. Red king crab settlers, once rare in historical surveys, are now more common throughout the region in low abundance. Benthic habitats did not change over time, as 90% of resampled sites had similar substrates. We conclude that larval supply and not benthic habitat is limiting juvenile recruitment. Our results could inform future fishery rebuilding efforts for blue king crab, which could include approaches to increase larval supply and juvenile recruitment through aquaculture.
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Drivers of bitter crab disease occurrence in eastern Bering Sea snow crab ( Chionoecetes opilio )
Abstract A recent population collapse of eastern Bering Sea (EBS) snow crab (Chionoecetes opilio) led to the first-ever closure of the snow crab fishery in 2022. The population collapse, caused, in part, by unprecedented warming, was preceded by peaks in juvenile snow crab density (2018) and bitter crab disease (BCD, Hematodinium sp.; 2016), a fatal crustacean disease. Annual bottom trawl surveys in the EBS show high year-to-year spatiotemporal variation in BCD-infected crab, yet it remains unclear what ecological drivers might explain the variation. We used statistical models of BCD presence/absence to examine the relative importance of intrinsic and extrinsic factors as drivers of BCD. We found a dome-shaped relationship between temperature and BCD presence, and results suggest that 2–4°C bottom temperatures are more likely to support BCD. Matching with past work across the globe, we find that stations with high population density of small, new shell crab are most likely to be BCD-positive. While our work highlights the challenges of disease monitoring in the EBS, our results indicate that indirect management measures related to snow crab rebuilding and recruitment may be more appropriate than directed fisheries management in mitigating BCD impacts.
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- Award ID(s):
- 1734999
- PAR ID:
- 10516241
- Publisher / Repository:
- Oxford University Press
- Date Published:
- Journal Name:
- ICES Journal of Marine Science
- Volume:
- 81
- Issue:
- 6
- ISSN:
- 1054-3139
- Format(s):
- Medium: X Size: p. 1073-1083
- Size(s):
- p. 1073-1083
- Sponsoring Org:
- National Science Foundation
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