盐度对棘头梅童鱼胚胎发育和仔鱼存活的影响

Effects of salinity on embryo development andlarval survival of Collichthys lucidus

观察比较了11个盐度梯度[0、5、10、15、20、25、30(自然海水)、35、40、45、50]下,棘头梅童鱼(Collichthys lueidus)胚胎的沉浮情况、孵化时间、孵化率和畸形率,并测定了初孵仔鱼的不投饵存活系数(SAI)。结果表明:(1)棘头梅童鱼胚胎在海水盐度为30及以上时100%漂浮;盐度为25时,95%漂浮,5%悬浮;盐度为20时95%悬浮,5%沉底;盐度为15时95%沉底,5%悬浮;盐度为10及以下时100%沉底。在水温18～20℃的条件下,棘头梅童鱼胚胎在盐度5～40范围内经28～32 h能孵化出仔鱼,盐度对孵化时间影响不显著(P>0.05)。但孵化率和畸形率因盐度不同而有显著差异。综合分析表明棘头梅童鱼胚胎孵化的适宜盐度范围为15～35,孵化最适盐度范围在20～30之间。(2)在可孵出鱼苗盐度范围(5～40)内,棘头梅童鱼仔鱼SAI值为(1.80±0.03)～(11.85±0.02),与卵的孵化率呈正相关关系。仔鱼生存的适宜生长盐度为10～30,最适盐度范围为20～25。

Sinkage,incubation time,hatching rate and abnormality rate of embryos of Collichthys lueidus wereanalyzed and survival activity index（SAI） of newly hatched larvae were observed under a gradient of different salinities. 11 different levels of salinity were set as follows ：0,5,10,15,20,25,30 （ natural seawater salinity ） , 35,40,45 and 50. The results showed： （ 1 ） the embryo floated 100% above salinity 30, and sank 100% below 10 ; at the salinity of 25,95% floated and 5% suspended ; at the salinity of 20,95% suspended and 5% sank ; at the salinity of 15, 95% sank and 5% suspended. The larvae were hatched after 28 - 32 h in water temperature 18 - 20℃, and the incubation time was not significantly affected by the salinity （ P 〉 0. 05 ）. Some larvae were hatched at salinity 5 -40, however, the hatching rate and abnormality rate were significantly different with the salinity changes. The results showed that salinities 15 - 35 were suitable and 20 - 30 were the best for hatching C. lucidus; （2） the SAI values of C. lucidus larvae at salinities 5 - 40 were（ 1.80 ±0.03 ） - （ 11.85 ± 0.02） and showed positive relationship to the hatching rate. The suitable salinity range for larval survival activity was 10 -30 and the optimum was 20 -25 according to SAI values.