Small-scale and short-term variation in food availability to natural oyster populations: Field observations and modeling results

Field studies were conducted at Confederate Reef, Galveston Bay to access the variability of food resources and water flow speeds on the short temporal and small spacial scales relevant to feeding in natural oyster populations. The quantity and quality of food resources varied. Food resources were plentiful but of low quality. Not one level of the water column was higher or lower in food than any other. Water flow speeds were also highly variable. Under most conditions, water flow speed was more important than food quantity in determining flux. Rapid flow rates result in high fluxes, and slow flow rates result in low fluxes. For oysters, water flow rate is very important in maintaining food supply. Models showed that water flow is very important in determining productivity because of its control on food supply. This emphasizes the necessity of measuring both food availability and flow speed.