盐度对卵形鲳鲹胚胎发育和早期仔鱼的影响

Effects of salinity on embryonic development and early larvae in ovate pompano Trachinotus ovatus

  • 摘要: 观察比较了10种不同盐度(5.0~50.0)条件下卵形鲳鲹 (Trachinotus ovatus) 受精卵的沉浮性、孵化率和畸形率,以及8种不同盐度(10.0~45.0)下仔鱼存活情况及不投饵存活系数(survival activity index,SAI)。结果表明,受精卵在不同盐度下表现出不同的沉浮性,在盐度为25.0以下的海水中呈沉性;在盐度30.0时为半沉浮性;在盐度为35.0的海水中呈浮性。盐度低于10.0或高于50.0,胚胎均不发育;在盐度15.0~45.0范围内,卵形鲳鲹胚胎能完成发育过程孵出仔鱼,但盐度对早期仔鱼的成活和畸形率的影响比较大。统计分析了总孵化率与盐度、畸形率与盐度的相关关系,求得胚胎孵化的预测适盐范围为14.9~39.4,最适盐度为26.0~28.2。在盐度25.0~30.0和无投饵状态下,仔鱼的SAI值为44.19~47.44。

     

    Abstract: The effects of salinity on the buoyancyhatching and abnormal rate of fertilized eggs of ovate pompano (Trachinotus ovatus) at 10 different salinities ranging from 5.0 to 50.0 were studied. Moreover, the survivorship as well as survival activity index (SAI) of larvae of T.ovatus at 8 different salinities ranging from 10.0 to 45.0were also observed. The results showed that different buoyancies of fertilized eggs were exhibited under different salinity conditions: all eggs sank at salinity bellow 25.0; most of eggs suspended in the middle of water at 30.0; all eggs floated on the surface at salinity above 35.0. Eggs did not hatch out at salinity below 10.0 or above 50.0, and the salinities for their hatching out ranged from 15.0 to 45.0. However, the effects ofsalinity on the survival rate and abnormal rate of early larval were significant. The relationship between total hatching rate and salinity variation as well as thatbetween abnormal rate and salinity was analyzed statistically. Expected suitable salinity for embryonic development was estimated as 14.9~39.4and the optimal salinity of 26.0~28.2. SAI value of early larvae was calculated as 4.19~47.44 under non-feeding condition and at salinities ranging from 25.0 to 30.0.

     

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