三峡库区木洞江段圆口铜鱼幼鱼的生长特征及资源保护

GROWTH FEATURES OF JUVENILE COREIUS GUICHENOTIAND ITS CONSERVATION IN THE THREE GORGES RESERVOIR

根据2007年6月至2008年11月在三峡库区木洞江段进行的船罾网渔获物调查的数据,运用FAO开发的体长频率数据分析软件FisatⅡ对圆口铜鱼幼鱼的生长、死亡参数以及种群补充模式进行了估算。结果表明:圆口铜鱼幼鱼的体长范围为20~231 mm,优势体长为40~80 mm,占74.67%;体长和体重的关系式为W=1×10-5L3.030 2,von Bertalanffy生长方程的各参数为:渐进体长L∞=694 mm,生长系数K=0.16,t0=-0.748。总死亡系数Z=3.101 a-1,自然死亡系数M=0.346 7 a-1,捕捞死亡系数F=2.754 3 a-1。种群补充模式表明,每年4~7月份为圆口铜鱼幼鱼主要补充期。开发率E=0.89,圆口铜鱼处于资源过度利用状态。因此必须加强对圆口铜鱼资源的保护,建议适当调整禁渔期,并取缔船罾网,以利于圆口铜鱼资源的恢复与保护。

Based on length-frequency data collected from trawl fishery survey in the Mudong Reach of the Three Gorges Reservoir from July,2007 to November,2008,growth,mortality and recruitment of juvenile Coreius guichenoti were estimated using FisatⅡsoftware.The results are summarized as follows:the length of C.guichenoti population ranged from 20 to 231 mm,40~80 mm being predominant;the relationship between body length(mm) and body weight(g) can be expressed as W=1×10-5L3.030 2;the estimated parameter for von Bertalanffy growth equation was L∞=694 mm,K=0.16,t0=-0.748.Total mortality(Z) was estimated as 3.101 a-1,natural mortality(M) 0.346 7 a-1,and fishing mortality(F) 2.754 3 a-1.The recruitment pattern was continuous with one major peak within the months from April to July.The exploitation rate in recent years was 0.89,and the resources of C.guichenoti were on the state of overexploitation in the study area.Therefore,it is suggested that protection and management of fish resources should be intensified,fishing ban period should be adjusted and the trawl net should be banned in order to restore and conserve the C.guichenoti resources.