Effects of desiccation practices and ploidy on Vibrio spp. abundances of cultured oysters, Crassostrea virginica

Abstract

The expansion of off-bottom aquaculture of the eastern oyster, Crassostrea virginica, to the Gulf of Mexico accompanied by high temperatures, which are correlated with Vibrio parahaemolyticus and Vibrio vulnificus, has raised human health concerns. Two routine oyster desiccation practices expected to elevate Vibrio spp. abundance in the oysters, 3 hour freshwater dip followed by 24 hour ambient air exposure and 27 hour ambient air exposure, were investigated in diploid and triploid C. virginica to determine the number of days of re-submersion prior to harvest necessary to drop Vibrio spp. levels back to ambient (non-elevated) levels. Results indicate that seven days of re-submersion allowed Vibrio spp. levels to return to submersed levels and decrease from elevated levels. This study found no consistent significant differences between ploidy, triploid and diploid, or desiccation practice, indicating no additional benefit or risk using either desiccation practice, with appropriate re-submersion time, or oyster ploidy.