Let’s Go Crabbing!

Nicole Doran, the Ohio State University

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This is me driving the boat to one of our sampling sites, photo credit to Stevie Czwartacki

The problem: If you go to any seafood restaurant in Charleston, South Carolina, there is a good chance that you will see dishes with blue crab in it. Blue crab (Callinectes sapidus) are popular on the East Coast, especially in South Carolina, Maine and Maryland because of their salty-sweet flavor, especially the lump meat that is used for dishes such as crab cakes! Because of the high demand for blue crab meat, it is one of the top three commercial fisheries in South Carolina, so this little crab plays a big role in the South Carolina economy.Something that could help resource managers and fisheries in predicting the fate of the blue crab is looking at their life histories, or how they reproduce, mature and behave throughout their life cycle. Blue crabs spawn in the sea and larvae move into tidal creeks and estuaries, where the salinity (salt concentration) is lower because of freshwater input. These important ecosystems serve as a nursery where juvenile crabs feed, grow, and mature. Then something interesting happens; the females migrate away from the tidal creeks back into the sea to spawn (release their eggs) while the male crabs typically remain in the creeks to live out the remainder of their lives. This pattern has been observed in the fishery’s trawl data, which shows catches from the ocean are predominantly female.

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A mature blue crab.  Photo:(http://www.dnr.sc.gov/marine/pub/ seascience/bluecrab.html)

The question I will be trying to answer is if male and female blue crabs tolerate high and low salinities differently. For my experiment, I collected juvenile crabs from creeks using trawl nets and crab pots, and will place the crabs in a laboratory setting in two different salinity conditions. Previous research has shown blue crabs grow at greater rates in high salinity, but not much research has been done on the physiological differences between males and females.

This work is important to the blue crab fisheries because local fishers and businesses rely on this crab as income and a food source. It is predicted that climate change will alter the environmental conditions in Charleston’s creeks and harbor, but it is uncertain how this could potentially affect the blue crab populations. By studying the conditions blue crabs are able to tolerate, resource managers can better understand how blue crab populations will respond to future environmental changes.

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Me on a boat surrounded by the crab pots used by the DNR and fishers to catch blue crab! Photo credit to Stevie Czwartacki

Acknowledgments 

I would like to acknowledge and thank the Fort Johnson REU program and NSF DBI-1757899 for making this research possible, the South Carolina Department of Natural Resources, Jeff Brunson, Stevie Czwartacki, and my mentor Dr. Michael Kendrick.

References

Archambault, J.A., Wenner, E.L., and Whitaker, J.D. 1990. Life history and abundance of blue crab, Callinectes sapidus Rathbun, at Charleston Harbor, South Carolina. Bulletin of Marine Science. 46(1): 145-158.

Cadman, Linda R. and Weinstein, Michael P. 1988. Effects of temperature and salinity on the growth of laboratory-reared juvenile blue crabs Callinectes sapidus Rathbun.  Exp. Mar. Biol. Ecol. 121: 193-207.

Mense, David J. and Wenner, Elizabeth L. 1989. Distribution and abundance of early life history stages of the blue crab, Callinectes sapidus, in tidal marsh creeks near Charleston, South Carolina. Estuaries. 12: 157-168.

Tagatz, Marlin E. 1968. Growth of juvenile blue crabs, Callinectes sapidus Rathbun, in the St. Johns River, Florida. Fishery Bulletin. 67: 281-288.

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