用1000 m L量筒进行全雌牙鲆卵浮性试验，每次取卵500粒，观察了全雌牙鲆卵在不同盐度下的悬浮状况。在不充气、不投饵、水温15～16℃条件下，取盐度试验孵化出的正常仔鱼100尾放入20 cm ×20 cm ×20 cm的小方型水槽中，设置10个盐度梯度，10、15、20、25、30、35、40、45、50，自然海水作对照；同时在不充气、不投饵、水温17～18℃条件下，取在自然海水中孵化出的正常仔鱼100尾放入20 cm ×20 cm ×20 cm的小方型水槽中，设置12个盐度梯度，5、10、15、20、25、30、35、40、45、50、55，自然海水作对照，观察不同盐度对全雌牙鲆胚胎发育及仔鱼存活的影响。试验结果表明，全雌牙鲆卵在盐度≤27时，全部沉底，盐度为27～30时，呈悬浮状态，盐度≥30时，全部上浮。胚胎发育在盐度为30～50时，孵化率均超过71．8％，差异不显著（ P＞0．05），畸形率小于4．3％；盐度为10～30时的孵化率超过64．5％，畸形率小于5．5％。盐度为10～25时的孵化率低于盐度30～50的孵化率，差异显著（ P＜0．05）；其畸形率高于盐度30～50的畸形率，差异不显著（ P＞0．05）。因此，高盐度比低盐度更适合胚胎发育。仔鱼在盐度为10～40时，均能很好地成活，盐度为20时，仔鱼的无投饵存活系数生存活力指数值最高。盐度5以下、50以上，仔鱼的无投饵存活系数小于5，仔鱼基本不能存活。%The sinking and buoyancy of eggs were observed in hologynic Japanese flounder Paralichthys oliv aceus under various salinities to investigate the effects of salinity on embryonic development and larval survival .The results showed that hologynic Japanese flounder eggs sank at a salinity of below 27 ,were pelagic at salinity from 27 to 30 ,and were buoyancy on the water surface at a salinity of above 30 .The hatching rate of over 71 .8% was observed at a salinity of 30-50 ,no significant difference (P>0 .05) ,and deformity rate of less than 4 .3% .The hatching rate of over 64 .5% was found at salinity from 10 to 30 , with deformity rate of less than 5 .5% .There was significantly lower hatching rate at salinity from 10 to 25 than that in salinity from 30 to 50 (P <0 .05) ,while there was higher deformity at salinity from 10 to 25 than that in salinity from 30 to 50 ( P > 0 .05 ) ,indicating properly high salinity more suitable for embryonic development .The larvae tolerated the salinity from 10 to 40 ,the maximal survival activity index (SAI) value of unfed larvae at a salinity of 20 .The unfed larvae had SAI value of less than 5 (mortality ) at salinity of below 5 and over 50 .
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