南海扁舵鲣生物学特性的初步研究

A preliminary study on biological characteristics of Auxis thazard in the South China Sea

根据2014年春、秋两季灯光罩网船在南海海域生产调查期间采集的扁舵鲣（Auxis thazard）样本,对其生物学进行初步分析。结果显示,春季扁舵鲣优势叉长为240-300 mm,占总数的60.3%,秋季为220-260 mm,占77.8%;春、秋季样本叉长与体质量关系式差异不大（P〉0.05）;春、秋季样本总体性比无显著差异,但各叉长组性比有显著差异（P〈0.001）;春季样本性腺成熟度各期均有分布,以Ⅰ期和Ⅱ期为主,且随着叉长增大,性成熟的雌鱼比例减小,雄鱼比例上升;不同性腺发育阶段的平均性腺指数（GSI）随着性腺的发育而上升,且雌性大于雄性;初次性成熟叉长为304.5 mm;摄食等级都以0级和1级为主,分别占总数的43.1%和43.4%。

We investigated the biological characteristics of Auxis thazard collected from light-falling net fishery in the South China Sea in spring and autumn of 2014. The results show that the dominant fork length ranged from 240 to 300 mm in spring while from 220 to260 mm in autumn,accounting for 60. 3% and 77. 8% of the total number,respectively. The relationship between fork length and body weight had little difference in spring and autumn. Significant difference was not found in total sex ratio in spring and autumn（ P〈0. 05）,but was found in fork length groups in spring and autumn（ P〈0. 001）. StageⅡ had the maximum maturity in spring. The proportion of mature females decreased and mature males increased with increasing fork length. With the development of gonad,the average GSI values increased at different gonadal stages and females had higher GSI values than males. The fork length of the first gonadal maturity was 304. 5 mm. Stage 0 and Stage 1 had the highest feeding intensity,accounting for 43. 1% and 43. 4% of the total number,respectively.