美国鲥鱼对我国淡水生态系统的潜在入侵风险

近年来美国鲥鱼已被引入到我国的上海和广东等地进行水产养殖。本实验报道了在纯淡水人工养殖条件下美国鲥鱼的繁殖和生长情况。人工养殖鲥鱼的生长速度接近美国北卡罗莱纳州沿岸野生鲥鱼的生长速度,而高于特拉华河野生鲥鱼的生长速度;人工养殖的2龄鲥鱼既可以在养殖池中自然产卵,也可以通过注射激素人工诱导产卵,其平均受精率、孵化率和仔鱼17天内的存活率分别约15%、75%和54%。这一结果表明,尽管鲥鱼是在海水中进行繁殖的洄游性鱼类,但在生长环境适宜的淡水条件下同样可以正常生长,并达到性成熟和繁育后代,有可能在适宜的淡水水体中形成自我维持的种群。结合本实验结果和美国鲥鱼的其他生物学特性,本文认为美国鲥鱼在我国天然水体生态系统中具有潜在的入侵性。

Potential invasion risk of the introduced American shad Alosa sapidissima to aquatic ecosystem in China

American shad Alosa sapidissima were introduced into China for aquaculture several years ago.Growth and reproduction of American shad maintained exclusively in artificial freshwater culture system were reported in this study.Size of cultured population in this experiment was similar to that of the wild population from the coastal North Carolina,and somewhat higher than that of the wild population from the Delaware River near Lambertville,USA.Two-year-old broodfish spawned naturally in ponds,or were induced to spawn with injections of Ovaprim.Mean fertilization,hatching and seventeen day survival rates of larvae were about 15%,75% and 54% respectively.These results indicate American shad can be successfully established in artificial freshwater culture system when its favorable living environments are provided.Based on these results and other biological characteristics,it can be concluded that American shad may become a potential invader to the aquatic ecosystem in China when escaping from farms.