北部湾多齿蛇鲻雌雄群体组成、生长、死亡特征的差异

利用2006年6月~2008年11月从广西北海,广东江洪、企水,海南东方、三亚等五个港口底拖网和流刺网渔获物中随机采集的样本,对北部湾海域多齿蛇鲻雌、雄群体的组成、生长、死亡特性进行了比较。结果表明,多齿蛇鲻雌性个体大于雄性个体,雌性渔获群体叉长范围104.3~398.0 mm,平均叉长215.4±62.9 mm;体重范围8.0~809.0 g,平均体重121.2±122.8 g;雄性渔获群体叉长范围122.7~345.0 mm,平均叉长211.1±45.9 mm;体重范围13.3~434.5 g,平均体重101.1±72.6 g。雌、雄个体数量不平衡,全年各月渔获量中雌性个体均多于雄性个体,雌、雄性比约为1.79∶1,周年变化呈现一定的波动,各月性比波动于1.29∶1~3.68∶1;雌、雄个体的性腺发育基本同步,但雄性个体比雌性个体进入性成熟季节的时间稍早;雌、雄群体的生长特性差异明显,生长参数K值分别为0.44 a-1和0.53 a-1,体重生长拐点年龄分别为2.41和1.97;雌、雄群体的死亡特征也存在明显差异,总死亡系数分别为2.73和3.01,自然死亡系数分别为0.89和1.04。

The difference of growth, mortality and group composition between female and male Saurida tumbil in the Beibu Gulf

The research on the difference of growth, mortality and group composition between female and male Saurida tumbil was carried out by making use of random samples from the catch got by bottom trawls and gill nets in the Beibu Gulf from June 2006 to November 2008.The result shows that female S. tumbil are bigger than male in size. The fork length constitution of the female S. tumbil ranges from 104.3 mm to 398.0 mm with the average of 215.4±62.9 mm.The body weight constitution of the female ranges from 8.0 g to 809.0 g with the average of 121.2±122.8 g.While the fork length constitution of the male ranges from 122.7 mm to 345.0 mm with the average of 211.1±45.9 mm and the body weight constitution of the male ranges from 13.3 g to 434.5 g with the averag of 101.1±72.6 g.There is an imbalance in the number between the female and the male.The female was more than the male in the catch of every month around the year.Sex ratio is 1.79:1 and annual change presents a certain undulation with the range from 1.29:1 to 3.68:1.Their gonadal development is almost synchronous,but the male reaches gonad maturation earlier than the female.There is a significant difference between the female and the male in growth.The turning point of body weight growth curve is situated at the age of 2.41 for the female while 1.97 for the male.The difference between the female and the male in mortality is also obvious.The total mortality coefficient(Z)is 2.73 for the female and 3.01 for the male while natural mortality coefficient(M)is 0.89 for the female and 1.04 for the male.