Effects of stocking density on the performance of Pacific white shrimp Litopenaeus vannamei cultured under pond and outdoor tank conditions using a high soybean meal diet

The objective of this study was to evaluate the effect of stocking density on the growth performance and economic feasibility for the culture of Litopenaeus vannamei fed plant based diets and cultured in production ponds and an outdoor tank system. juvenile shrimps (0.015 g initial weight) were stocked in sixteen 0.1 ha ponds with stocking densities of 17, 26, 35, and 45 shrimp m(-2) and cultured under standardized pond production conditions for 16 weeks. Daily feed rates were predetermined using expected growth per week of 1.3 g. a feed conversion ratio (FCR) of 1.2, and an estimated survival rate of 78%. Additionally, juvenile L vannamei (2.8 g initial weight) were stocked into 24,800-L tanks at the densities of 15, 25, 35, 45, 55, and 65 shrimp m(-2) with 4 replicates per treatment and cultured for 10 weeks. Daily feed inputs were calculated based upon an expected weekly weight gain of 1.3 g and an expected FCR of 1.2. At the conclusion of the trials, final production, final mean weight, FCR, size distribution and survival were determined. The results for the pond study demonstrated that there was a trend of negative correlation between stocking density and growth. Mean final weight (+/- SD) of shrimp across treatments ranged from 20.70 to 25.25g. Survival ranged from 58.0 to 65.1%, and FCR was between 1.17 and 1.54. These differences were not significant (P >= 0.10) among treatments, however, higher stocking density resulted in significantly greater yield. Final production was between 2660 and 6149 kg ha(-1). There were no significant differences in partial returns among different densities for the pond study. The results for the outdoor tanks showed that shrimp growth were inversely related to stocking density, with mean final weight ranged from 13.42 to 16.13g. Final biomass ranged between 286.15 and 637.20 g tank(-1). There was a negative correlation between stocking density and FCR with FCR ranging from 1.15 to 1.54. Survival ranged from 93.4 +/- 5.6 to 100.0 +/- 0.0%, however, there was no significant effect of stocking density on survival rate. Additionally, there were no significant differences in production value and partial income data among treatments under pond production study. (C) 2011 Elsevier B.V. All rights reserved.