Effects of stocking density，water quality and multi-stage rearing strategy on Siniperca chuatsi fry culture

To study the effects of stocking density，water quality and multi-stage rearing strategy on fry culture of Siniperca chuatsi in concrete tanks，different stocking densities and three stage rearing were designed in the experiment and the water quality was detected. S. chuatsi was fed with live fry of Cirrhinus mrigala. The results showed that， the proper stocking density of S. chuatsi fry at small size（< 2.5 cm）was 4 000 individuals/m3，while no more than 800 individuals/m3 at a larger size（2.5-6.5 cm）. There was a positive relationship between the concentrations of NH4 +-N，NO2 --N and the stocking density. The higher was the stocking density of fry culture of S. chuatsi，the more diseases came up. The difference of body size became wider when the fry grew to 2-3 cm，5-6 cm，8-9 cm. Three-stage rearing could effectively increase fry size uniformity and improve the survival rate significantly