根据2007年7—10月西北太平洋海域采集的1342尾柔鱼样本,分析其性腺成熟度和性腺成熟度指数等生物学特征,进行繁殖生物学研究。结果表明,总性别比均接近1:1,性成熟个体的雌性比例小于雄性,说明雄性繁殖期较长,性成熟较早。性成熟个体比例的动态变化表明,9月底雌性达到性成熟高峰。8—10月胴长组成出现双峰结构,对应于未成熟、性成熟个体,同时存在少量繁殖后雌性个体。渔获组成表明,捕获样本中存在较大胴长的秋季产卵群体和个体较小的冬春生产卵群体。雌、雄柔鱼初次性成熟胴长分别为33.17cm和29.90cm。性腺成熟度指数(GSI)与胴长之间呈现显著的线性关系(雌性GSI=0.0093ML+0.0084;雄性GSI=0.15ML-3.313),这也说明雄性性腺发育较快。
Reproductive biology dynamics including sex ratio,maturity stage and gonado-somatic index(GSI)were analyzed based on the 1342 neon flying squids continuously sampled in the northwest Pacific Ocean from July to October,2007.The total sex ratio of female to male was kept at 1:1,but for matured individuals females were less than males,indicating that the male squid has longer breeding season and matures earlier.Dynamics of percentage of matured individuals showed that females reached the reproductive peak at the end of September.During August—October,mantle length structure had 2 modes corresponding to immature and mature individuals,but there was a small group of spent females existing.These results suggest that the study region has an autumn-spawning cohort with great length and a winter-spring spawning cohort with low length.The mantle length at first maturity for females or males was 33.17 or 29.90cm,respectively.There was a regression relationship between GSI and mantle length(ML/cm)(GSI=0.0093ML+0.0084 for females and GSI=0.15ML-3.313 for males).It is suggested that the reproductive system growth of males increases with the growth of body.