Effect of stocking density on zootechnical parameters of shrimp Litopenaeus schmitti culturea

Abstract

Litopenaeus schmitti post larvae (0.081 ± 0.01 g) were cultured at the Marine Shrimp Laboratory of Federal University of Santa Catarina (LCM í  UFSC). The present study aimed to evaluate the effects of three stocking densities (8, 20 and 50 shrimp m^-2) on zootechnical parameters. Shrimps were fed 4 times a day with a feeding rate that varied from 3 to 50% of biomass; water exchange varied from 5 to 50%. The data were analyzed by one-way analysis of variance (ANOVA), followed by Tukey test to determine differences among treatments (Pâ"°¤0.05). The results showed significant differences in productivity: 463.2, 918.5 and 2,340 kg ha^-1 per cycle, representing the treatments 8, 20 and 50 shrimp m^-2, respectively. Survival was over 90% for 20 and 50 shrimp m^-2. Greatest final weight was obtained in the density of 8 shrimp m^-2 (8.20 g) while in 20 and 50 shrimp m^-2 densities the final weight were 4.95 and 5.38 g, respectively. The best weekly growth rate was obtained with 8 shrimp m^-2 (0.55 g). Feed conversion rate (FCR) showed no significant differences and range from 3.58 and 4.43. Water quality variables (dissolved oxygen, pH, salinity, transparency, ammonium, nitrite, nitrate and total suspended solids) did not demonstrate significantly differences between treatments, being acceptable ranges for shrimp culture. These results indicate effect of stocking density on final weight (negative), weekly growth rate (negative) and productivity (positive).