Outbreaks of pathogenic V. parahaemolyticus severely restrict both recreational and commercial shellfish harvesting and threaten the vitality of the $108 million per year shellfish industry in Washington State. Currently there are no predictive tools available to shellfish growers and health managers to provide advanced warning of outbreaks. Instead, managers must rely on the results of intensive and sometimes ineffective monitoring programs to detect increases in V. parahaemolyticus populations. Outbreaks can occur with little or no warning leaving managers and shellfish growers little time to react and initiate the appropriate mitigation measures. This can result in costly recalls of contaminated shellfish, create a public health hazard and also reduce consumer confidence. The goal of this project is to identify oceanographic and climatic patterns associated with high densities of V. parahaemolyticus in the environment and occurrences of illnesses associated with consumption of oysters. Forecasts of "high risk" ocean and climate conditions may then better enable managers to initiate proactive mitigation strategies to minimize illnesses.