Evaluation of Stocking Density and Feeding Regime on Production of Red Swamp Crawfish in Outdoor Mesocosms

Seven stocking densities and three feeding regimes were evaluated, in combination, to determine their effects on production and relative condition of red swamp crawfish, Procambarus clarkii, in outdoor mesocosms. Juveniles were grown from November through June at densities of 5 to 35/m2 with either no cultivated rice, cultivated rice, or cultivated rice+formulated pellets as food resources. Crawfish size was influenced primarily by stocking density, survival was equally influenced by density and feeding regime, and yield was affected mostly by feeding regime. Individual harvest weight and survival decreased with an increase in stocking density. Most crawfish exceeded 20 g at 5 and 10/m2 in treatments with cultivated rice, but significant stunting occurred in all feeding regimes at 15/m2 or higher. Survival decreased with increased density, and was significantly less in the no-rice system, presumably from starvation and cannibalism. Mean crawfish yield in rice (1549 kg/ha) and rice+feed (1629 kg/ha) treatments was about 2.5 times higher than in the no-rice treatment (618 kg/ha). Formulated feed did not prevent stunting at high densities, but crawfish provided feed were in better physiological condition. Planted rice with an initial population density of about 10/m2 appears to provide the best combination to maximize both size and yield.