丹江口水库凶猛鱼集团生长特性组型的聚类分析

ANALYSIS OF CLUSTERING ON GROWTH OF PREDATORY FISH GUILD IN THE DANJIANGKOU RESERVOIR

选择体重-体长关系W=aL^b中的回归系数a和回归指数b;阶段生长参数的年增长、相对增长率、体长生长比速、生长常数、生长指标和体重的年增重、相对增重率、体重生长比速、年增积量;一般生长型的渐近体长、渐近体重、生长系数、起点年龄、拐点年龄、拐点体重、拐点瞬时增重率等18个反映鱼类生长特性的指标,运用系统聚类方法,将丹江口水库5种主要凶猛鱼组成的集团,从生长特性的差异上划分为大、中、小3个组型,并对划分结果的具体应用和鱼类集团划分的依据等问题进行了讨论。

From October 1986 to November 1987, in Danjiangkou Reservoir of Hanjiang Valley, 1192 specimen of five predator fish, Elopichthys bambusa, Culter mongolicus, C. alburnus, Silurus asotus, and Siniperca chuatsi were collected for the prensent study. Eighteen indices were selected in the calculation of exponential similarity coefficient of Hier-achical Clustering Methods. Thus, the five species were regarded as a guild of predators, and sub-divided into three growth groups, including large-sized group of E. bambusa, middle-sized group of Cullers, and S . chuatsi. and small-sized group of S . asotus.