R/ODR-15

Description:

There is presently an increasing effort to plant specific pathogen-free (SPF) seed oysters on beds in the upper low-salinity reaches of many estuarine rivers to manage around disease by avoidance. But simply planting SPF seed in these areas may not prevent subsequent infections by Perkinsus marinus (dermo) if resident oyster populations harbor and transmit this disease. Whether dermo disease transmission and mortalities among planted SPF seed occur may depend on temperature, salinity and the prevalence and intensity of P. marinus infections in resident native oyster populations (Burreson and Ragone Calvo 1996). Due to limited availability of SPF seed oysters, it is imperative that they be deployed by strategies which maximize their resource enhancement return. To inform and validate such strategies, we propose to empirically determine the seasonal dynamics of dermo disease transmission to SPF seed planted at three salinity regimes in enzootic estuarine waters, to localize tissue sites of early P. marinus lesions to elucidate probable portals of pathogen entry, and to determine effects of environmental parameters and resident oyster disease status on disease transmission rates, and on subsequent seed oyster growth and survival rates.