Studies On Technique Of Artificial Larva Rearing And Acclimating Seedlings By Pellet Feed In Trachidermus Fasciatus

Sexually matured Chinese rough-skin sculpin (Trachidermus fasciatus) were captured from Qinhuangdao gulf. Artificial hatch and larva rearing for Trachidermus fasciatus was carried out and observation was also made on embryonic and larval development. After seedlings being cultured for 40d, we come to desalt the culture media with different gradients to find out the most optimum velocity of desalting seawater. In addition, with the experiment on domesticating Trachidermus fasciatus seedlings by pellet feed, we studied the effects of different feeds on effectiveness of feeding, survival rate and development in body weight and length. The data were further carried on regression analysis for the relationship between different feeds and development in body weight and length.The results of the studies showed: (1) After cultured for two weeks, semen was able to be squeezed out of 4 male Trachidermus fasciatus among the 9 parents fish (5 ♂ /4♀ ) . 2 female parents fish laid eggs in the daytime and another 2 at night. We observed that one female laid eggs twice. In addition, two female parent fish laid ova on oyster's shell but another two on the bottom of aquaria. (2)From the gonads of the four dissected female parents fish, the grade of maturity of gonads were all above III phase with maturing coefficients in the range from 24.5% to 34.0%, and the higher the maturing coefficient was , the more mature the gonad was; Absolute fecundity varied from 1274 to 5439, and was a positively related to body weight. Relative fecundity varied from 98 to 122 ind/g. (3)Trachidermus fasciatus reproduced adhesive and agglomerated eggs, which colored orange or yellowish with the diameter of from 1.45 to 1.60 mm. Under the condition of increasing oxygen and keeping water flowing, zygotes hatched after 24~27d. Water temperature in course of hatching gradually increased from 7°C to 12°C, and hatching rate was 74% . (3)After desalting seawater, death rates of velocity I (0.003 kg/L . d) and velocity II (0.005 kg/L . d) all were 2% , and rates of velocity III(0.007 kg/L . d) and velocity IV (0.009 kg/L . d) were respectively 6% and 12%. This study indicated that the most optimum velocity of desalting of seawater was 0.005 kg/L .d. (5)Feeding rate for live chironomid larvae was highest (100%), for the trash fish was 98%; and for the formulated pellet feed was 65%. Survival rate of Trachidermus fasciatus fed with trash fish meat was highest (100%); fed with live chironomid larvae was lower (90%); and with formulated pellet feed was lowest (75%). Formulated pellet feed was inferior to the other two kinds of...