浙江海域蓝圆鯵年龄和生长的研究

蓝圆鲹在东、黄、南海均有分布,是围网渔业的主要捕捞对象,本文将分布于东海北部一个数量较大的群体进行了年龄和生长的研究。基础材料取自1980年5月到1983年4月浙江海域围、拖网等渔获物中共2727尾渔获物样品,选择其中644尾的鳞片和耳石作了年龄鉴定和生长研究。结果表明:蓝图鲹的鳞片和耳石显示的年轮特征均甚清晰,都是一年形成一次,出现年轮的时间大部在5—6月;蓝圆鲹体长与体重的关系式为:W=1.652×10~(-6)L~(2.947),其生长规律可用von Bertalanffy的生长方程描述,求得长度生长方程的各个参数是:L_∞=361毫米,K=0.276,t_0=-1.846;求得重量生长方程的各个参数是:W_∞=570克,K=0.282,t=-1.80,其重量生长曲线的拐点位于t=2.098龄处。

THE AGE AND GROWTH OF ROUND SCAD OF ZHEJIANG OFFSHORE WATERS

Round secad (Decapterus maruadsi), a widely distributal fish.is one of the main targets for purse seine fishing in China. This study is based onobservation of scales and otoliths of 644 fishes collected from commercial catches offZhejiang coast from January of 1981 to March of 1983. The results are summarized asfollows: 1. The scales and otoliths are reliable in age determination of this species. Newrings are formed once a year, and they usually appear in May and June. 2. The body length and the scale length prescnt a linear relation: L=1.259R-2 .691.The correlation equation of the body length and weight is W=1.652×10~(-5)L~(2.947). 3. The growth rate of the fish is uneven within a year. The growth is rapidfrom May to Oct. and is slow from Nov. to April. 4. The general law of growth between years may be expressed by von Dertalanf-fy growth equation. The changing feature in the growth process is charanacterized bythe body length and weight tending towards the asymptotic value with the increase oftime. The growth rew and acceleration tend to the zero gradually, The length seemedto be more rapid tending to the terminal than the weight.