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

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.