Study on artificial breeding technology of cultured Takifugu ocellatus

Objective The study aims to analysis the growth, reproduction, and gonadal development of Takifugu ocellatus under artificial breeding conditions.

Methods The growth and gonadal development of artificial breeding T. ocellatus F₁ were observed by three-year artificial culture, and the effects of different salinity (0, 5, 10, 15, 20, 25, 30) on the fertilization and hatching of mature eggs of T. ocellatus F₁ were studied during the breeding season.

Results 1) The body mass were (55.4 ± 14.6) g at one year old, and (105.9±25.8) g at two years old, and (148.0 ± 35.5) g at three years old under freshwater rearing conditions, respectively; most individuals could develop to sexual maturity at two years old. 2) T. ocellatus reproduced once a year in the Zhangzhou area of Fujian, and the breeding time was from early October to mid-November. The gonads of female fish could develop to stage Ⅳ from 2-year-old to 3-year-old in freshwater culture conditions, but they couldn’t naturally ovulate. Female broodstocks could obtain physiologically mature eggs after injection of the hormone HCG or LRH-A. 3) Salinity had a significant effect on the fertilization of mature eggs and hatching of fertilized eggs of T. ocellatus. When the salinity was 0, mature eggs couldn’t be fertilized, and fertilized eggs couldn’t be hatched; when the salinities were 5.0 and 10.0, the fertilization rate and hatching rate were 78.6%, 94.4%, and 7.6%, 31.3%, respectively. 4) The eggs of T. ocellatus were adhesive eggs, and that of the diameter of egg after water absorption and expansion was 1.131 to 1.163 mm. The absolute egg production was (1.92－6.25)×10⁴ eggs of female broodstocks which body mass changed from 82.3 g to 115.7 g. It took 5－6 days from fertilized eggs to the hatching of fry under the conditions of salinity 20 and water temperature 20.2－25.5 ℃.

Conclusion The successful full-artificial breeding of T. ocellatus can initially solve the problem of seedling sources, and also lay a foundation for the research on the artificial mass breeding and the release of wild resources.