Larval reảing of striped catfish (Pangasianodon hypophthalmus) in recirculating aquaculture system at diffẻrent stocking densities

Abstract

Striped catfish Pangasianodon hyphophthalmus is the main cultured species in the Mekong Delta. Total production 1.31 million tons and exported value 2.26 billion USD (2018). However, the main problem in larval rearing is low survival rate due to the cannibalism, lack of feed at the first feeding and unstable the water quality. The objective of the study is to find the appropriate density of striped catfish in RAS to apply this technology to practical production. The experiment include 3 treatments with differences stocking densities 5, 10 and 15 inds/L was performed on a 200L tank, connected to a recirculating aquaculture system. The live foods at first 2 weeks are copepods, rotifers and moina with densities from 3-10 inds/mL. Results showed that during the experiment, water quality (temperature, pH, DO, TAN and NO2 - ) had slight fluctuation but still in suitable range for striped catfish in all treatments. After 45 days, growth rate included weight gain (W45), daily weight gain (DWG), specific growth rate (SGR) were not significant difference (p>0.05) between all treatments. The highest survival rate (20.7±2.2% and 20±2.1%) achieved at rearing densities of 5 and 10 inds/L, these were significantly higher than the survival rate at treatment 15 inds/L. Therefore, it is possible to recommend a suitable stocking density in RAS to be 5-10 inds/L