BIODIVERSITY OF SESSILE AND MOTILE MACROFAUNA ON INTERTIDAL OYSTER REEFS IN MOSQUITO LAGOON, FLORIDA

Abstract

Our research focused on determining the diversity and abundance of sessile and motile macrofauna that use intertidal reefs of the eastern oyster Crassostrea virginica for feeding, settlement space or refuge in Mosquito Lagoon, Florida. Five replicate lift nets were deployed at six sites (three impacted reefs with seaward margins of disarticulated shells, three reference reefs without dead margins) to determine the species composition and numbers present on these reef types. All nets were deployed intertidally on backreef areas on living oyster reefs, just above mean low water. One and a half liters of live oysters and oyster shells were placed in each net (1m2) on deployment. Nets were surveyed for all fauna monthly for one year. Metrics used to evaluate habitat use were species richness (total number of different species found) and density (total number of organisms per net). Comparisons were also made between community assemblages found on the two different types of reefs in the area (with and without dead margins) and for sessile species, recruitment on living oysters versus disarticulated shells. Forty sessile and 64 motile species of macroorganisms were found utilizing the oyster reefs in Mosquito Lagoon. However, recruitment on live oysters was twice that on disarticulated shells. Significant temporal variations were documented. When the two reef types were compared, however, no differences were found.