Blue Crab Habitat Study

The blue crab (Callinectes sapidus) is an important fishery species in coastal Florida. Reliant on coastal biogenic habitats, blue crabs may be sensitive to changes in the distribution of different foundation species. Due to climate change, it is imperative to understand how the displacement of salt marsh by tropical mangroves will affect blue crab abundances. This project will investigate the abundance, diet, and chemotaxis of blue crabs in salt marshes versus mangroves along the Florida. Activities to be Undertaken: 1) Assess the abundance of blue crabs in mangrove, salt marsh, and mixed stands along the ecotone between these two habitats; 2) Investigate chemotactic response to chemical signals from salt marsh and mangrove vegetation; and 3) Using stable isotope analysis, determine the contribution of salt marsh versus mangrove biomass to blue crab diets. This study will reveal how blue crabs are affected by the displacement of salt marsh by range-expanding mangroves along Florida’s coastal fringe. Censuses will reveal habitat suitability for blue crabs of different age classes, lab experiments will reveal crab sensory capability and preference in distinguishing between mangrove and salt marsh habitats, and stable isotope analyses will detect to what degree these different foundation species are important for food. This work will benefit recreational and commercial fishers of blue crabs, which constitute a $15.3 million fishery in Florida. Outreach activities in Cedar Key and Gainesville will inform the public on issues surrounding fisheries management and habitat conservation in response to climate change.