中西印度洋的黄鳍金枪鱼繁殖生物学研究

根据我国国家金枪鱼渔业观察员2012年10月-2013年1月和2013年10月-2014年2月两个阶段在印度洋中西部采集1233尾黄鳍金枪鱼的样本,对其进行了繁殖生物学的研究,主要分析黄鳍金枪鱼纯重、叉长、性比、性成熟率和性腺指数等繁殖生物学参数。结果表明:(1)雌性雄性叉长-纯重关系式分别是W=7×10-6L3.244和W=6×10-6L3.197;(2)雌雄之比为0.74∶1,达到性成熟的雌雄个体性别比为0.69∶1;(3)雌性性腺指数为0.39~5.92,在雌性个体中性腺指数大于2的占52.03%;雄性性腺指数为0.44~3.37,在雄性个体中性腺指数大于2的占31.43%。(4)雌、雄性成熟叉长的Logistic曲线分别是P=1/1+e0.08276×(122.991-FLm)]和P=1/1+e0.03767×(118.618-FLm)];(5)采样期间(10月至翌年2月)雌、雄性个体分别在12月和1月的性成熟率达到最高,在2月份性成熟率最低;(6)根据体长分布推算,叉长为115 cm可以作为黄鳍金枪鱼个体分为大小两个群体的基准,雌雄样本中大个体所占比例分别是63.13%和75.40%,两个群体中,雌雄个体大小存在显著性差异(P0.05)。本文的研究结果有助于更好地了解印度洋西部黄鳍金枪鱼的生物学特征,为我国进一步开发该种渔业资源提供基础资料。

Study on reproductive biology of yellowfin tuna (Thunnus albacares) in the Central and Western Indian Ocean

Yellowfin tuna (Thunnus albacares) is the main target species for Chinese tuna fisheries fleets in Indian Ocean. According to a total of 1233 yellowfin tuna samples collected by Chinese national observers in the central-western Indian Ocean during two stages (Oct. 2012-Jan. 2013 and Oct. 2013-Feb. 2014),we conducted the study on the reproductive biology of this tuna. The main reproductive biological parameters were estimated in this study. The results indicated: (1)The relationship between fork length and dressed weight for female and male were W=7×10^-6L^3.244 and W=6×10^-6L^3.197, respectively. (2) From these samples, the total sex ratio of female to male was 0.74:1, and the sex ratio was 0.69:1 in such mature samples. (3) The gonadsomatic index for female and male were calculated from 0.39 to 5.92, and from 0.44 to 3.37, respectively.(4) The logistic regression was described the relationships between fork length and maturity for both female and male which were P=1/1+e^{0.08276×(122.991-FLm)}] and P=1/1+e^{0.03767×(118.618-FLm)}], respectively. (5)The maturity analysis showed that the percentages of female and male samples which reached mature were highest in January and December, respectively. And the lowest percentages of both female and male were in February. (6) The cut-off point for larger and smaller groups was 115 cm,and the percentage of larger female and male were 63.13% and 75.40%,respectively, which was significantly different between male and female. This study will contribute to the evaluation for this fish resources.