【摘要】 <正> 鱼类的种群结构是该物种主要的生存形式之一,而任何一种生存形式都是以达到繁衍后代和保持其一定数量对环境条件适应的结果,查明其存在形式对了解该物种的历史发展掌握和种群动态有重要意义。带鱼Trichiurus haumela(Forskl)在我国渔业经济中占有重要位置,五十年代以来,其产量基本呈上升趋势,七十年代中期产量开始有所波动;在不断增加捕捞强度下单更多还原

【Abstract】 The hairtails were sampled from April to June 1978 to 1979, April to October 1980 and April to May 1981 in northern East China Sea. Specimens were obtained from 8667 hairtails. The results are as follows. The seasonal variation of age composition shows that the population consists of four generations (0—3 years old). But only two generations (0—1 year old) play an important part in the catches. 98 per cent of fish were 1 year old and 0 year old fish dominated catches throughout the year. Those over 2 years old account for a small amount in the catch stock. The age composition of the population after August became more complex than that before. The occurrence of 0 year old and 1~- year old (the later brood group of last year) makes the structure of population more complicated. The population can be divided into schools that are different in biological conditions. The hairtails inhabiting the Haijiao area are of medium lengths, that outside the Haijiao area are either smaller or larger. The length composition of the population during the 1978—1981 period showed little variation from year to year; modal lengths ranged (May to June) from 180 to 240 mm. Age composition showed also little change from year to year. However difference were obvious in length and age composition of hairtails as compared with that in the past. This might have been due to excess exploitation. A comparative analysis of the population structure of hairtails with Large Yellow Croaker will show the following characteristics: 1. It has shorter life-span (maximum age of the 6 years) and its age composition is rather simple (4 age groups). 2. The population attains sexual maturity much earlier and its recruitment is rather fast (the process maturation takes about one year). 3. The population possesses higher reproduction capacity.更多还原