Study on white leg shrimp (Litopenaeus vannamei) co-culture with different densities of sea grape (Caulerpa lentillifera)

Abstract

This study was performed to assess the effect of using different densities of sea grape (Caulerpa lentillifera) in coculture with white leg shrimp (Litopenaeus vannamei) on water quality and shrimp performance. Five treatments were randomly designed in triplicate tanks. Shrimp were monocultured as control treatment, while shrimp in the other four treatments were cocultured with sea grape at different densities (0.5, 1, 1.5 and 2 kg/m3) were randomly designed in triplicates. Shrimp juvenile with mean initial weight of 0.37g were stocked at a density of 300 ind./m3 in 500-L plastic tanks, at salinity of 30 ppt for 56 days. The results showed that water quality parameters in terms of nitrogen compounds (TAN, NO2-, NO3-) and PO43- in coculture tanks were much lower than in the monoculture. Survival, final weight, and productivity of shrimps varied in the ranges of 54.8-78.5%, 12.29- 16.47 g/ m3 and 2.02-3.87 g/m3, respectively of which the coculture treatments were significantly higher compared to those in the control group (p<0.05). Moreover, feed conversion ratios (FCR) in the coculture groups (0.80-0.87) were significantly lower than in the monoculture group (0.97). Applying coculture of shrimp and sea grape at a density of 1 kg/m3 gave relatively better shrimp performance and FCR than other sea grape densities, although not significantly. These results suggested that sea grape can be applied at densities of 0.5-2 kg/m3 in coculture with white leg shrimp, of which 1 kg/m3 gave high production and feed efficiency.