CHARACTERIZATION OF ORGANIC PARTICLES ASSOCIATED WITH RAPID GROWTH IN JUVENILE WHITE SHRIMP, PENAEUS-VANNAMEI BOONE, REARED UNDER INTENSIVE CULTURE CONDITIONS

Aquaculture ponds possess unique ecological characteristics which contribute significantly to the growth and survival of the target species. In this study, shrimp growth rates were monitored in microcosm tanks containing flow-through water with varying concentrations of organic particles produced autochthonously in an intensive shrimp pond. Rapid growth occurred in unfiltered pond water with a mean particulate organic carbon (POC) concentration of 6.98 mg/l over six sampling days. In contrast, slowest growth occurred in well water with a mean POC concentration of 0.38 mg/l. Within the POC pool, as the percentage of living carbon increased, shrimp growth rates increased. Unfiltered pond water contained more than 45% living carbon, whereas well water had greater than 85% detrital carbon. Living biomass was dominated by pennate and centric diatoms, whereas contributions from bacteria and protozoans were minor. There was a highly significant linear relationship between shrimp growth and POC concentration (r2 = 0.895, p < 0.0001), although there appeared to be a minimum threshold concentration below which shrimp growth was unaffected. Temporal variability in algal cell density (ACD) indicated a bloom and crash cycle, suggesting that the availability of live algal cells to shrimp was sporadic. Further research on pond ecology is needed in order to manipulate organic carbon pools to improve shrimp growth.