滆湖天然鱼类小型化及其对策

ON TBE CAUSES OF MINIATURIZATION OF FISH COMPOSITION AND CORRESPONDING COUNTERMEASURE IN LAKE GEHU

本文通过1986～1988年对滆湖几种渔具(特别是簖)的渔获物进行的统计,对鲫、红鳍鲌、乌鳢等鱼类的生物学特性的研究,分析了滆湖鱼类的群落和种群结构中存在的小型化现象?峁砻?群落结构中以小型、低值鱼类和种群结构中低龄鱼占有较大的比例。用Bertalanffy生长方程和Beverton-Holt,动态综合模式分析了鲫种群数量变动,据此提出了合适的捕捞强度和起捕规格。本文还从湖泊渔业生态系统角度,探讨了造成滆湖天然鱼类小型化的原因及其相应的对策。

The present paper deals with the fact of miniaturization of fish communityand population structures through analysing the fish catch and the characteristics of fishbiology (gut contents, growth, reproductive habits, etc.)of Carassius auratus, Cultererythropterus, Channa argus sampled from weirs and other fishing gear in Lake Gehuduring 1986-1988. The results show that the small-sized, low-value fishes in thecommunity and young fishes(younger than 1^+ group)in population take high proportions. The von Bertalanffy's growth equation and Beverton-Holt dynamic pool model areused for analysing the population dynamics of Carassius auratus. On the ecosystem ofLake Gehu fisheries, the causes of miniaturization of fish composition and correspondingcountermeasure have been discussed. An optimal age for first catch and optimal fishingintensity are suggested.