网湖似刺鳊鮈种群生长和死亡率研究

STUDY ON THE POPULATION GROWTH AND MORTALITY OF PARACANTHOBRAMA GUICHENOTI BLEEKER IN WANGHU LAKE

本文根据６６９尾标本，研究长江中游网湖小型经济鱼类似刺鳊的种群生长和死亡率，从理论推导证明，鱼类的生长拐点与其临界年龄是一致的，并据以对网湖似刺鳊等小型经济鱼类的合理渔业对策问题进行了初步分析讨论。

The present paper deals with the population growth and mortality of Paracanlhobramaguichenoti.A total of 669 specimens were collected from Wanghu Lake during the periodnom l985 to·1986.Data of the scales were used to detenlline the age and to backcalculatethe body length of the fish at various ages.The relationship between body length and scaleradius can be expressed as the following equation:L=76,24l3R￣(0.6762) and the weight-lengthrelation as:W=1.0889×10￣(-5)L￣(3.1012).Von Bertalanffy growth equation was fitted to the bodylength and also body weightin relation to ages as:Lt=254.4 (1-e￣((-0.4518(t+0.19)) and Wt=314.0(1-e￣((-0.4518(t+0.19))￣3.1012 At different age intervals of the catch, the total mortality was 0.72 with 0.37 and 0.35 forthe natural and fishing mortalities respectively. The age of the inflection point of the bodyweight coincides with the critical age of the maximum generation biomass.It is at age 2.32year,and correspondingly the body weight is 94.4g for the species studied。In order to maintain a sustainable fisheries in lake,the rational exploitation of the stock15 discussed.