The Stepwise Intermediate Culture of Trachinotus ovatus Fingerlings in Large Cage

Key words: 
• Trachinotu ovatus /
• fingerlings /
• survival rate /
• stepwise intermediate culture /
• length concentration ratio

Abstract: A new model for intermediate culture of Trachinotus ovatus fingerlings in large cage was designed,and the main technical parameters were determined by experiment. This culture model included three stages of culture:primary,secondary and tertiary,and the initial size of Trachinotus ovatus fingerlings were 2. 9^-3. 2 cm. For the primary,secondary and tertiary culture the stocking densities were 280^-300 ind·m^-3,150-180 ind·m^-3 and 120-150 ind·m^-3,respectively,and the net mesh size was 2 a = 1. 2 cm,2. 0 cm and 3. 0 cm,respectively.The fingerlings were selected by sieving for the secondary culture when they were 4. 4 cm or more long and accounted for（ 40 ±2） % of the total. Likewise,the fingerlings of 5. 8 cm or more were sieved and selected for tertiary culture when they were（ 90 ±2） % of the total. The fingerlings were sieved for adult fish culture when they were7. 2 cm or more long and made up（ 90 ±2） % of the total. When cultured in this model,the fingerlings had a survival rate of more than 85%,and the number of fingerlings with the body length between 7. 2 cm and 8. 2 cm accounted for more than 85%. Compared with the traditional culture,this culture model had a higher survival rate by above 10%,reducing the production cost effectively and increasing the profit.