澜沧江中国结鱼人工驯养和繁殖技术研究

Domestication and Artificial Propagation of Tor sinensis in Lancang River

开展中国结鱼的人工驯养和人工繁育,为中国结鱼的物种保护和资源恢复提供基础技术资料。用于研究的中国结鱼后备亲鱼于2019年6-7月分批次来源于澜沧江景洪江段,体质健壮无伤,共50尾,1-5龄,水泥池培育。经过1年驯养(水温19.6-29.0℃),中国结鱼成活率90%,体增重80%-100%。选择体重大于3.0 kg的雌亲鱼和体重大于2.0 kg雄亲鱼用于繁殖,2020年10月24日采用2次注射法人工催产20尾亲鱼,针距11-12 h,效应时间11-20 h,共产卵3万粒,平均受精率2%。受精卵倒入纱网孵化框放入水泥池中流水孵化,密度为1.0×10^(5)粒/m^(3),自然水温(24.3-25.3℃),共产卵3万粒,只出苗500多尾,经84-90 h孵化,获得初孵仔鱼。仔鱼用5%甲醛固定后电子显微成像系统拍照观察,初孵仔鱼全长1.10 cm;8日龄50%以上的鱼苗已经开口摄食;11日龄仔鱼卵黄吸尽;32日龄进入稚鱼期。

Wild Tor sinensis populations have drastically declined due to the development and opera⁃tion of cascaded hydropower stations on Lancang River.Therefore,breeding and release is important for protecting and restoring the Tor sinensis population.In this study,we illustrated and described the process of domestication and artificial propagation of Tor sinensis at Nuozhadu fish breeding station.The objective was to provide basic data for conserving and restoring Tor sinensis.Results show that the gonads of Tor sinensis matured under the condition of flowing water in a cement pond and the fish could be induced to spawn artificially.On October 24 of 2020,8 females and 12 males were selected for artificial spawning and propagation.Fish were injected twice,with an interval of 11-12 h,and the response time was 11-20 h.A total of 30,000 eggs were obtained and fertilized by dry method of artificial fertilization with an average fertilization rate of 2%at a water temperature of 24.3-25.3℃.The zygotes were incubated under flowing water at 24.3-25.3℃,with an incubation density of 1.0×10^(5) eggs/m^(3).The release of newly hatched larvae from the membrane was at 84-90 h after fertilization,and a total of 600 larvae hatched.The total length of the newly hatched larvae was 1.10 cm,and the yolk was completely absorbed by day 11.Over 50%of the larvae were feeding on day 8 and developed to the juvenile stage at day 32.The results of this study will provide a theoretical reference for artificial propagation and release of Tor sinensis and the success of this artificial propagation effort helps assure future large-scale artificial propagation and release.