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Abstract Coastal habitats are experiencing decreases in seawater pH and increases in temperature due to anthropogenic climate change. The Caribbean king crab,Maguimithrax spinosissimus, plays a vital role on Western Atlantic reefs by grazing macroalgae that competes for space with coral recruits. Therefore, identifying its tolerance to anthropogenic stressors is critically needed if this species is to be considered as a potential restoration management strategy in coral reef environments. We examined the effects of temperature (control: 28 °C and elevated: 31 °C) and pH (control: 8.0 and reduced pH: 7.7) on the king crab’s larval and early juvenile survival, molt-stage duration, and morphology in a fully crossed laboratory experiment. Survival to the megalopal stage was reduced (13.5% lower) in the combined reduced pH and elevated temperature treatment relative to the control. First-stage (J1) juveniles delayed molting by 1.5 days in the reduced pH treatment, while second-stage (J2) crabs molted 3 days earlier when exposed to elevated temperature. Juvenile morphology did not differ among treatments. These results suggests that juvenile king crabs are tolerant to changes associated with climate change. Given the important role of the king crab as a grazer of macroalgae, its tolerance to climate stressors suggests that it could benefit restoration efforts aimed at making coral reefs more resilient to increasingly warm and acidic oceans into the future.
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Blue king crab ( Paralithodes platypus ) and red king crab ( P. camtschaticus ) juvenile settlement to nearshore nursery habitats of Saint Paul Island, Pribilof Islands, Alaska
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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- Award ID(s):
- 2022190
- PAR ID:
- 10658082
- Publisher / Repository:
- Canadian Journal of Fisheries and Aquatic Sciences
- Date Published:
- Journal Name:
- Canadian Journal of Fisheries and Aquatic Sciences
- Volume:
- 82
- ISSN:
- 0706-652X
- Page Range / eLocation ID:
- 1 to 21
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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Abstract Blue crab (Callinectes sapidus) supports lucrative Mid‐Atlantic crustacean fisheries and plays an important role in estuarine ecology, so their larval transport and recruitment dynamics in the Maryland Coastal Bays system were investigated using simulated and observed surface drifters. Relative contributions of winds, tides, density gradients, and waves to larval recruitment success were identified during the spawning season, particularly under hurricane conditions in 2014. Based on temperature (e.g., 19–29°C) and salinity conditions (e.g., 23–33 PSU), particles representing virtual blue crab larvae were released into the model domain from early June to late October 2014. During the spawning season, variations in the larval recruitment success caused by wind speed and direction, tides (e.g., affecting through inlets), density gradients (e.g., salinity variations), and surface gravity waves were 17%, 4%, −9%, and 17%, respectively. During Hurricane Arthur (2014), variability of self‐recruitment success caused by density gradients are negligible while by other three factors are comparable at 3%–4%. Surface drifter experiments support the modeling results that larval recruitment success is strongly associated with the coastal circulation. The high (low) self‐recruitment success in the Assawoman and Chincoteague Bays (Sinepuxent Bay) is related to the locally weak (strong) circulation; released larvae escape from inlets are likely recruited to southern Fenwick and northern Assateague Islands, and the coastal regions outside the Chincoteague Inlet. Understanding physical factors influencing larval recruitment success helps resource managers make informed decisions about habitat restoration and harvest regulations, in addition to seafood‐related food security.more » « less
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- Free Publicly Accessible Full Text
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Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.1139/cjfas-2024-0227
