中文摘要：

为了解早期多级分养对翘嘴鳜（Sinipercachuatsi）的生长及水质影响，用网箱将翘嘴鳜幼鱼在不同培育密度（1000，1500，2000尾／m2）下进行连续三级筛选养殖试验。结果显示，各密度组鳜幼鱼的生长速度存在差异，随着养殖密度的增加，鱼体生长速度降低；存活率在中等密度（1500尾／m2）组最高；在鱼苗3cm之后，水体氨氮含量显著性升高。结果表明，三级分养策略可以有效提高苗种规格整齐度；使存活率显著性提高。鱼种在幼鱼早期生长速度快，需注意此阶段的营养需求。

英文摘要：

This experiment studied the effects of early size grading on growth and water quality of mandarin fish （ Siniperca chuatsi ）. Three-stage rearing strategy was carried out in mandarin fish fry at different rearing density （1000, 1500, 2000 individuals per m2 ） in experimental cages. The results showed that, the fish fry growth speed was reduced with the stocking density increaseing. The survival rate of the fry rearing in medium density （ 1500 individuals per m： ） was the highest. After the fry grew up to 3 cm in length, the water content of ammonia inwater increased significantly. The results showed that three-stage rearing strategy could effectively increase fry size uniformity and improve the survival rate significantly. We should also pay attention to the nutritional requirements at the early larval stage for its fast growth.