北部湾二长棘鲷生长、死亡及其群体组成

利用2006年7月至2008年3月北部湾渔业商业捕捞底拖网和刺网渔获物中采集的样本,对北部湾二长棘鲷的生长、死亡及其群体组成进行了初步研究。结果表明,北部湾二长棘鲷优势体长70～140 mm,占82.2%;优势体重为20～60 g,占54.29%;ARSS分析表明雌雄生长不存在显著性差异(P>0.05),繁殖期性比为1.21∶1;von Bertalanffy生长方程的主要参数分别为:L∞=292.8 mm,K=0.167,t0=-1.116;体重的生长拐点为5.463龄;总死亡系数、自然死亡系数和捕捞死亡系数分别为1.041 4、0.282 8和0.752 6,当前开发率为0.728。

Growth, Mortality and Population Composition of Crimson Sea Bream, Paragyrops edita Tanaka in Beibu Gulf

Growth,mortality and population composition of crimson sea bream Paragyrops edita Tanaka were studied according to data collected in fishery-dependent bottom trawl and gillnet fleets caught in Beibu Gulf from July 2006 to March 2008.The result showed that the dominant length of the Paragyrops edita Tanaka ranged from 70 to 140 mm,accounting for 82.2%of the total;the dominant weight was between 20 g and 60 g,accounting for 54.29% of the total.ARSS indicated that there were no significant differences in growth between the male and female(P>0.05),and the sex ratio in spawning season is 1.21 to 1.The estimated parameters for von Bertalanffy growth function of the stock were L∞=292.8 mm,K = 0.167 and t0 =-0.116,respectively.The turning point in body weight growth curve of the stock was situated at the age of 5.463.The instantaneous rates of total mortality,natural mortality and fishing mortality were 1.0414,0.2828 and 0.7526,respectively.The exploitation rate in recent years was 0.728.