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在室内水池以溢水法收集真鲷 (Pagrosomusmajor)受精卵 ,并置于不同盐度海水中静水孵化 ,孵出仔鱼以流水培育。设置盐度梯度为 17.0、2 2 .0、2 7.0及自然盐度 3 3 .0 ,水温分别为 19.5～ 2 1.5℃ (孵化 )、2 0 .5～ 2 3 .5℃(培育 )。结果表明∶①真鲷受精卵在自然盐度海水中发育很好 ,孵化率较高 ( 85 .0 %～ 97.0 % ) ,畸形率较低 ( 3 .2 %～ 2 3 .7% ) ;在低盐度条件下静水孵化 ,发育不好 ,孵化率为 4 8.0 %～ 1.0 % ,且盐度越低 ,孵化率也越低。充气孵化时 ,盐度低至 17.0 ,孵化率有时也可达 97.1% ,但畸形率高达 85 .7%～ 10 0 %。②孵化仔鱼中有 2类畸形 ,第 1类畸形表现为身体或尾部弯曲 ,油球位于卵黄囊中部或前部 ,油球数多于 1个 ,盐度越低 ,畸形率越高 ;第 2类畸形表现为仔鱼膜膨大、围心腔扩大 ,这类畸形只出现于低盐度条件下 ,盐度越低 ,畸形率越高 ,且往往与第 1类畸形症状并发。③不同盐度对真鲷仔稚鱼的生长速度没有显著影响 ,各盐度条件仔稚鱼经 3 1d的培养 ,其平均全长为 19.6～ 2 0 .7mm( P >0 .0 5 ) ,没有显著的差别。④海水盐度越低 ,仔稚鱼的存活率越高 ,各组的平均存活率为 ,盐度17.0时 ,3 6.3 % ;盐度 2 2 .0时 ,3 6.2 % ;盐度 2 7.0时 ,2 7.1% ;盐度 3 3 .0时 ,16.3 %。
Pagrosomus major zygotes were collected by overflow method in indoor ponds, incubated in still seawater with different salinity seawater, and hatched larvae were cultured in running water. The salinity gradients were set at 17.0,2.2.0,2 7.0 and natural salinity at 33.0. The water temperature was 19.5-2.15 ℃ (incubation) and 20.5-5.2 ℃ (incubation) respectively. The results showed that: (1) The zygophila eggs developed well in natural salinity seawater with high hatching rate (85.0% -97.0%) and low deformity rate (3.2% -2.37%). Under low salinity conditions, the water still hatched and developed poorly. The hatching rate was 4 8.0% -1.0%, and the lower the salinity, the lower the hatching rate. Inflatable incubation, the salinity as low as 17.0, hatching rate sometimes up to 97.1%, but the deformity rate as high as 85.7% ~ 100%. There were two kinds of deformities in hatching larvae, the first type of deformity manifested as body or tail bending, the oil ball located in the middle or front of the yolk sac, the number of oil balls more than one, the lower the salinity, the higher the deformity rate; the second Class deformities showed laeval inflated membrane, enlarged cardiac cavity, such deformities only appear in low salinity conditions, the lower the salinity, the higher the deformity rate, and often associated with the first category of deformity symptoms. ③The salinity had no significant effect on the growth of juvenile seabream, and the average length of the juvenile juvenile was 31.6-20.7 mm (P> 0.05) No significant difference. The lower the salinity of seawater, the higher the survival rate of juvenile larvae was. The average survival rates of each group were 3 6.3% at salinity 17.0%, 6.22% at salinity 2 2.0% and 2 7.0% , 21 7.1%; salinity 33.0, 16.3%.