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根据2012年9-12月所罗门群岛海域采集的307尾长鳍金枪鱼样本,分析其性别比、性腺成熟度和性腺指数等繁殖生物学参数。结果表明:繁殖群体总性别比和性成熟个体性别比均不符合1:1(P<0.05),雄性个体比例大于雌性,性别比在产卵期间出现一定波动,但普遍小于1:1。性别比与个体大小密切相关,雄性比例随叉长增长而降低。性成熟度分析表明,产卵期间性成熟个体比例达到70%以上,其中存在大量的产卵后群体,未成熟比例较低。雌性不同性成熟度大小差异明显(P<0.05),但雄性并不明显(P>0.05)。相同性成熟度雄性个体平均叉长均大于雌性,但并没有体现出一致的变化。雌、雄个体初次性成熟叉长分别为84.88 cm和85.61 cm。性腺指数(GSI)在各性成熟度和叉长组间存在显著差异(P<0.05),雌性GSI大于1.2几乎全部为成熟个体,尤其GSI大于2普遍为即将产卵(Ⅴ期)和产卵后(Ⅵ期)群体;雄性个体GSI普遍小于2,各叉长组雌性GSI普遍高于雄性,这表明雌性性腺发育较快。而调查期间9月GSI均值明显高于其他3月(P<0.05),综合分析认为该海域长鳍金枪鱼9-10月达到产卵高峰期。
Based on the sample of 307 long-handled albacore tuna collected in the Solomon Islands from September to December 2012, reproductive biology parameters such as sex ratio, gonadal maturity and gonadal index were analyzed. The results showed that the sex ratio of reproductive population did not fit 1: 1 (P <0.05), and the proportion of male individuals was greater than that of female. The sex ratio fluctuated during the spawning period but was generally less than 1: 1. The sex ratio is closely related to the size of the individual, and the proportion of males decreases as the length of the fork increases. The analysis of sexual maturity showed that the proportion of sexual maturity individuals reached more than 70% during the spawning period, among which there were a large number of post-oviposition groups with low immature percentage. The difference of female sexual maturity was significant (P <0.05), but the male was not obvious (P> 0.05). The same-degree maturity male average fork length is greater than females, but did not show a consistent change. The initial maturity length of female and male individuals were 84.88 cm and 85.61 cm, respectively. The gonadal index (GSI) was significantly different between the sex maturity and the long fork group (P <0.05). Female GSI> 1.2 was almost all mature individuals, especially the GSI> 2 was generally about to lay eggs (Ⅴ) (Group VI). The GSI of males was generally less than 2, and the female GSI of each fork was generally higher than that of males, indicating that female gonads developed rapidly. During the survey period, the average GSI in September was significantly higher than that in other March (P <0.05). According to a comprehensive analysis, the average length of GSI reached the peak of spawning from September to October in this area.