盐度对拟目乌贼受精卵卵径、重量和孵化率的影响

Effect on Diameter,Weight and Hatchability of Fertilized Egg of Cuttlefish(Sepia lycidas)by Different Salinity Water Environment

在水温(23±0.5)℃、pH 7.0~8.0、溶解氧>5mg·L-1的条件下,研究孵化过程中不同盐度对拟目乌贼胚胎发育和孵化率的影响。结果表明,拟目乌贼卵透明略带奶油色,近椭圆形,短径为0.596~1.758cm,长径为1.452~3.136cm,刚产出的卵重约2g;孵化完成时,卵膜内的重量达到4.5g。在盐度为28‰时,经过28~30d孵化,卵的短径和长径平均分别增加了0.601、0.615cm,孵化率为57.0%;盐度为23‰时,卵的长径和短径也相应增加,增幅分别为0.567、1.263cm,孵化率为13.5%;盐度为33‰时,经过28~30d孵化,卵短径平均增长0.150cm,而长径却缩短了0.141cm,孵化率为9.5%;在盐度为13‰、18‰、38‰和43‰条件下,胚胎停止发育,孵化率为0。结果表明,拟目乌贼属于狭盐性种类,盐度变化对拟目乌贼胚胎发育和孵化有直接影响。

In the temperature(23±0.5)℃,pH 7.4,dissolved oxygen> 5mg·L-1 water environment conditions,the effect on hatchability,weight and diameter of fertilized egg of cuttlefish Sepia lycidas was determined at different salinity.The results showed that fertilized egg was transparent and slightly creamy,nearly oval,short diameter of 0.596~1.758cm,long diameter of 1.452~3.136cm.Just produced egg was about 2g in weight,and hatching finished egg weight was about 4.5g.Short diameter and long diameter of fertilized eggs respectively increased 0.601cm,0.615cm at the salinity 28‰ water environment conditions,and the hatching rate was 57.0%.Long diameter and short diameter of fertilized eggs respectively increased 0.567cm and 1.263cm at the salinity 23‰ water environment conditions,and the hatching rate was 13.5%.Short diameter of fertilized eggs increased 0.150cm,while long diameter decreased 0.141cm at the salinity 33‰ water environment conditions,and the hatching rate was 9.5%.At the salinity 13‰,18‰,38‰and 43‰,the hatching rate was 0.It showed that Sepia lycidas belonged to stenohaline and salinity had a direct effect on its embryonic development and hatchability.