新疆乌伦古湖河鲈二十年来种群生长变化及原因

Perch (Perca fluviatilis Linnaeus) growth variation and inducing reasons of Lake Ulungur,Xinjiang Province in the last two decades

新疆乌伦古湖是中国内陆主要渔业基地之一.为了充分开发其渔业资源,在过去的40余年中共引进鱼类15种;乌伦古湖土著鱼类的生态位大部分已经为外来鱼类所占据,曾为乌伦古湖最重要的土著经济鱼类的河鲈物种濒临灭绝.为了探讨河鲈种群数量锐减的原因和外来鱼类对乌伦古湖土著鱼类的入侵机制,2007-2008年对乌伦古湖河鲈的生长状况进行了调查,并与1987-1989年的调查数据进行了比较分析.调查结果表明:除1^+龄组外,乌伦古湖河鲈其它各龄组的平均体长和体重均明显减小;拟合Von Bertalanffy生长方程的各参数L_∞=41.317cm,W_∞=15475.1g,k=0.1649,t_0=-0.2626;求得生长特征指数φ=2.4493.L_∞和φ值明显减小,k值有所增加;但生长式型没有改变,生长拐点与1987-1989年一致,仍为t_(IP)=7.探讨了乌伦古湖河鲈种群生长变化的主要原因及作用机制.

Lake Ulungur is one of the most important fishery ground in Chinese inland area. To exploit the potential fishery resources, 15 species of fishes were introduced in the past 40 years. By far, most of the niches to the fishes endemic in Lake Ulungur were occupied by the introduced fishes. Perch（Percafluviatilis Linnaeus） as the most economic important fish has endangered. The age structure and growth of perch population were studied in 2007-2008, and compared with the corresponding data in 1987-1989 to analyze the reason why population size decreased sharply. Body weight and length of captured perch were both smaller than those in 1987-1989 at each age except age 1^＋. The growth parameters using Von Bertalantty equations were L∞=41.317cm, W∞=15475.1g, k-0.1649, t0=-0.2626; growth performance indices were Ф=2.4493. L∞ and Ф reduced since 1987-1989 while k increased. However, the growth inflection point of body weight was the same as 1987-1989 （r=7）. This investigation confirmed the remarkable effects of environment factors on perch growth and the effect mode of fish invasion on Perch（Perca fluviatilis Linnaeus） growth in Lake Ulungur were also revealed.