所罗门群岛海域长鳍金枪鱼繁殖生物学初步研究

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84．88cm和85．61cm。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。

Preliminary Study of Reproductive Biology of Albacore in the Waters of Solomon Islands

Reproductive biology parameters including sex ratio, maturity stage and gonadosomatic index （GSI） and so on were analyzed based on the 307 albacore （Thunnus alalunga） individuals continuously sampled in the waters of Solomon Islands from September to December, 2012. The results showed that the sex ratio foralbacore and mature individuals were both significantly different from the expected l：l（P〈O.05）, indicating that the proportion of female was higher than for male in the catch. The sex ratio is always below 1：1 and fluctuate during the spawning season, and closely related with body size, with the proportion of males increasing wit] size. Mature individuals accounted for more than 70% with a great deal of post-spawning, but only few immature individuals during the spawning season based on maturity stage analysis. And the difference of bod size for females in maturity stages was detected （P〈0.05）, but was not significant for males （P〉O.05）. The men fork length （FL） of males was larger than for females at the same maturity stage, however, their differences wer not always significant. The FL at first maturity for females and males was 84.88cm and 85.61cm, respectivel3 GSI changes with maturity stage and FL increasing （P〈0.05）, females with GSI〉I.2 were classed as mature especially most with GSI〉2.0 were either active-spawning （stage V） or post-spawning （stage VI）. The GSI c females was larger than for males at the FL classes which suggested that the gonad of females develops faster than for males. While the mean of GSI for September was the highest during the survey months. Spawnin activity of albacore peaks between September and October in the waters of Solomon Islands based on th results of comprehensive analysis.