Productive performance of the nile tilapia (<em>Oreochromis niloticus</em> L.) in tanks with different water exchanges and stocking density in raceway

Abstract

Nile tilapia, Oreochromis niloticus L. (Perciformes Cichlidae) fingerlings were stocked at 90, 120 and 150 fishes in 24 circular tanks (0,5 m³), submitted to two full water exchanges, in a 30 and 60 minutes, in raceway system, to evaluate productive performance. The performance results were analyzed through a completely randomized design, in a 3x2 factorial scheme. After 128 days, the final weight and the weight gain were higher in larger water exchange and lower stocking density. The feed conversion ratio with non-significant statistical differences. The total biomass increased with the water exchange and stocking density increasing for 120 and 150 fishes/m³; the specific growth ratio increased with water exchange increasing; the fillet yield and the carcass yield decreased significantly with lower water exchange and bigger stocking density. In this research, it was concluded that the best performance parameters were obtained with full water exchange in 30 minutes, at bigger stocking densities.