R/ODR-30

Strategic focus area:

Description:

*This project is a continuing project initially funded through award NA05OAR4171042 (year one) and currently funded through award NA10OAR4170072 (year two)* Objectives: We propose to test the relationship between diel cycling hypoxia, "infection risk," and the acquisition and progression of Perkinsus marinus infections in the Eastern oyster, Crassostrea virginica, in shallow waters within Chesapeake Bay. Specifically, we will examine (1) the effect of temporally varying patterns of hypoxia in shallow subestuaries and embayments on the acquisition and progression of P. marinus infections in C. virginica, and (2) how the interactive effects of temporally varying hypoxia and P. marinus infections influence oyster mortality and growth. Methodology: Field deployments of P. marinus-infected and uninfected oysters at shallow-water water quality monitoring sites will be used to examine the relationship between diel cycling hypoxia and the acquisition and progression of infections in the field. Experimental deployments of infected and nominally infection-free oysters will be complemented with assays of infection risk that used qPCR techniques to quantify waterborne P. marinus abundances. Laboratory experiments in which we specifically manipulate the diel DO cycle will allow us to isolate hypoxia effects from other environmental covariates. Rationale: In spite of a rich body of literature, the link between water quality and fisheries in Chesapeake Bay remains unclear. A better understanding of the reciprocal influences of fisheries and water quality is critical to maximizing the potential for water quality improvements to enhance the health of exploited populations and the sustainability of fisheries, and for restoration and management of harvested species to benefit water quality. Results will provide an important basis for coordinated geographic targeting of water quality and oyster restoration efforts; spatial linkage of fisheries and water quality restoration targeting is an important step towards ecosystem-based management in Chesapeake Bay.