The Observation Early Development Of Embryos And Larvae Of Siniperca Scherzeri

Artificial propagation tests on Siniperca scherzeri broodstock of wild and atificially cultured in a pond were succesfully spawned under controlled conditions in2011～2013. Siniperca scherzeri, which is one of the most important economical freshwater fish, distributed in China uniquely. In recent decades, the resources of Siniperca scherzeri declined rapidly because of the deterioration of ecological enviroments and excessive catching. In order to protect and exploit it reasonally, the artificial propagation was conducted in Fujian province. The fertilized eggs were obtained by injecting interior hormone into the parent female fish and using artificial dry-fertilization, and were hatched at temperature20℃. The development of embryo and larva of Siniperca scherzeri were observed consecutively. The morphological feature and development characteristics of Siniperca scherzeri were described during the embryo and larva stage. The adhesive egg were found to be about glutinous, light yellow in color, and (1.76±0.08)mm in diameter,(2.20±0.09)mm5min after fertilization and inflation. When water temperature was20℃, the hatching time was189.33h, and the newly hatched larvae had mean total length (5.57±0.18)mm and phototaxis. Under the water temperature24℃, the larvae began feeding on3days old and entered the mixed nutrition stage and the phototaxis disappeared. The yolk-sac exhausted at the5days old, their oil globes were absorbed completely at the6days old and the larvae came into the stage of nutrition outside completely. There was an extremely significant linear relationship between total length and age:y=0.4916x+5.7209(P＜0.01) The effects of temperature on the embryonic development of Siniperca scherzeri were investigated in this study. The results showed that the embryo could be hatched at the range of18～28℃, and with the increase of temperature, the periods of embryonic development reached blastula, gastrula and hatching stage were relatively shorter, temperature had little effects on the development of blastocyst stage before, after embryos developped into blastocyst stage, elevated temperature significantly speed up the process, incubation time shortened with the increase of temperature. There was a very significant negative correlation between incubation time (T) and temperature (x), and the equation was T=306738x-2.463,R2=0.9966(P＜0.01). The mortality rates were lower and the hatching rates were higher when embryionic developped into the mid gastrula stage at the range of18～26℃, and the difference between groups was not significant (P<0.05). When the temperature reached28℃, the mortality rate of the mid gastrula stage increased very significantly, and the hatching rate decreased very significantly (P＜0.01). There was a very significant square curve correlation between hatching rate(y) and temperature(x), and the equation was y=-1.0321x2+44.107x-379.99,R2=0.9174(P<0.01). The optimal temperature range for fertilized eggs hatching was20～26℃.