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PROGRESSION OF DISEASES CAUSED BY THE OYSTER PARASITES, PERKINSUS MARINUS AND HAPLOSPORIDIUM NELSONI, IN CRASSOSTREA VIRGINICA ON CONSTRUCTED INTERTIDAL REEFS
Volety, A. K., F. O. Perkins, A. R. Mann, AND P. R. Hershberg. PROGRESSION OF DISEASES CAUSED BY THE OYSTER PARASITES, PERKINSUS MARINUS AND HAPLOSPORIDIUM NELSONI, IN CRASSOSTREA VIRGINICA ON CONSTRUCTED INTERTIDAL REEFS. Presented at International Conference on Shellfish Restoration, Hilton Head Island, SC, November 18 - 21, 1998.
The progression of diseases caused by the oyster parasites, Perkinsus marinus and Haplosporidium nelsoni, were evaluated by periodic sampling (May 1994-Dec. 1995) of oysters, Crassostrea virginica, that set on an artificial reef located in the Piankatank River, Virginia, in August 1993. The infections observed were recorded as a function of 1) prevalence and intensity, 2) oyster size and age, and 3) depth below mean low water at which the host oyster was found on the reef. Only a very small (insignificant) number of oysters were infected with the two species of pathogens on the oyster reef during the first eleven months of life. In the second year of oyster life, epizootiological patterns of disease development followed temperature and salinity trends. Oysters at residence depths =45 cm below mean low water exhibited significantly (P<0.0001) higher prevalence and intensity of infections than oysters at depths =90 cm. In contrast, oysters at residence depths =90 cm had significantly higher growth rates (P<0.05) than those at =45 cm. However, size differences were not significant (P>0.05) at the end of the study. Results from the curent study may be used in managing oyster fisheries on natural or artificial reefs.