The project of cultivation of oyster has been designed to evaluate the growth rate, the mortality, the reproductive effort, production and biochemical composition of the oyster function of the density and the depth. This plan was intended: - to build model of growth rate, - to demonstrate the action of the different parameters on growth rate (temperature, food effect...), - to evaluate the density effect to see if the available food could be a limiting factor, - to estimate the effect of the depth joined to the impact of the high turbidity near the bot tom, - to detect the mortality related to the prevalence of diseases. The project began in July 1989 by dredging 20 000 small oysters at the mouth of the Patuxent River near Cove Point. Three experimental stations were selected in the Patuxent River to set up the structures, Benedict Bridge in the upper and the brackish water zone, Green Holly Pond at the mouth of the river and Chesapeake Biological Laboratory's Piero