Benthic Environments VII: Shallow-Water Habitats Posters - Ocean Sciences [OS]

Benthic Environments VII: Shallow-Water Habitats Posters - Ocean Sciences [OS]: "The Importance of Benthic Macro-algae (Gracilaria) as a Refuge Habitat for Juvenile Blue Crab, Callinectes sapidus
* Falls, J A (jfalls@vims.edu) , William & Mary Virginia Institute of Marine Science, P.O. Box 1346 Rt. 1208 Greate Road, Gloucester Point, VA 23062 United States
Seid, C (gs04@vims.ed) , Thomas Jefferson High School fo Science and Technology, 6560 Braddock Road, Alexandria, VA 22312 United States
Lipcius, R (rom@vims.edu) , William & Mary Virginia Institute of Marine Science, P.O. Box 1346 Rt. 1208 Greate Road, Gloucester Point, VA 23062 United States

The availability of nursery habitats for juvenile blue crabs is important to population persistence. Prior studies have shown the importance of sea grass, shallow mud flats, and marshes as nurseries for blue crab recruits. The importance of benthic macro-algae like Gracilaria has not been previously demonstrated. In summer 2005, a mesocosm predation study was used to compare the mortality of free and tethered juvenile crabs in contained mudflat and macro-algal systems. Juvenile crabs (12mm-21 mm carapace width) were placed in these systems with larger blue crabs (80mm-140 mm carapace width) as predators. The tanks were checked once or twice daily and the survival time in hours was recorded. In addition, suction sampling was used to compare juvenile crab abundance between mudflat and macro-algal habitats in the field. The results indicate that crabs survive longer in habitats with macro-algal nursery habitat, which may therefore be a critical nursery habitat. The field comparison is continuing and will be completed fall 2005. "