太湖鲫鱼生物学调查和增殖问题

INVESTIGATION ON THE BIOLOGY AND PROPAGATION OF CRUCIAN CARP IN TAI HU

本文对太湖鲫鱼种群的性状、年龄结构、生长速度、性成熟年龄、产卵群体组成和繁殖力、产卵习性以及渔业动态等生物学特性作了重点调查;并就其实际产量至今仍低于50年代初期水平的原因和增殖问题作了初步探讨。共采集标本5批,计887尾。

The biology and propagation of crucian carp Carassius auratus Linnaeu in Tai Hu had been investigated during 1979 to 1982,again in 1989.Eight hund red and eighty seven specimens were collected and studied.The age structure of these collections was composed of 5 age classes from age o to age 4 and the age group of o-2 contributed more than 90% of the collections.The growth of body length is faster in the first two years and then decreased greatly with age,but the body weight is increased with age(Table 3).The largest specimen collected male was 20.2era in length and 306.6g in weight,female was 24.5em in length and 512.4g in weight.The fish at- tained sex maturity at age 1.Spawning ocuures from April to August.The reproductive stock was formed by 4 age classes from age 1 to age 5.Fishes at age 1-2 contribuled 75.6% of the breeding stock(Table 5).The fecundity was varied from 1056 to 56187 and increased rapidly with age(Table 6).The population abundance was significantly decreased during 1960-1970s. and the present yield of the fish was lower than that in 1950s.In order to develop the population, thea author gave suggestions on regulating minimum mesh size and protecting the spawning ground.