【摘要】 1998— 2 0 0 2年期间 ,向长江放流人工繁殖中华鲟 2月龄稚鲟 (全长 7 5— 17 0cm) 17 5 2万尾 ,其中 7795 7尾用CWT进行标记 ;14月龄幼鲟 (全长 5 5 0— 98 0cm) 4 0 0尾 ,全部用外挂银牌和CWT双重标记。放流后沿长江及沿海收集中华鲟稚鲟和幼鲟样本 ,4年共回收稚鲟样本 6 4 0 0尾 ,幼鲟样本 13尾 ,检测到携带标记的稚鲟和幼鲟各 13尾。人工放流的幼鲟降海洄游的速度平均达到 2 8 6km/ 2 4h(7 1— 10 0 2km/ 2 4h) ,回捕时离放流点的距离从 346—2 4 5 9km ,平均 16 0 0km ,回捕的标志幼鲟有 4 6 2 %的个体来自海区。初步估算出 1999年和 2 0 0 0年人工放流个体在长江口幼鲟种群中的贡献率分别为 2 2 81%和 0 997%。结果表明 ,人工放流中华鲟稚鲟和幼鲟的生长、洄游及分布与自然种群没有明显差异。放流较大规格的幼鲟有利于提高成活率 ,而目前长江中华鲟种群的补充仍以自然繁殖种群为主。更多还原

【Abstract】 From 1998—2002,1752 thousands of juvenile Chinese sturgeon were released in the Yangtze River.Among them,77957 of two month old fingerlings(7 5—17 0cm Total Length)were tagged with Coded Wire Tags,and 400 fourteen month old juveniles(55—98cm Total Length)were tagged with both Coded Wire Tags and external silver tags.We sampled fishes after the release along the Yangtze River and costal areas.Within four years,6400 fingerlings and 13 juveniles were captured.All captured juveniles were tagged and only 13 individuals of captured fingerlings were with tags.No significant difference between the wild fish and cultured released stock regarding the growth and the timing of appearance in the mouth of the Yangtze River.The average downstream migration speed of released juveniles was about 28 6km/d(7 1—100 2km/d),with average distance between the release and recapture sites was 1,600 km,ranging from 346km to 2,459km .46 2% of recapture happened in the ocean.Based on the initial estimates,the contribution of culture released juveniles to the natural juvenile stock in the estuary of the Yangtze River is 2 281% in 1999 and 0 997% in 2000,respectively.The wild stock of Chinese sturgeon is still the main source to maintain the population in the Yangtze River.However,to release larger juveniles could contribute more to the maintaining of Chinese sturgeon population since the survival rate of them would be much higher than the fingerlings.更多还原