西北太平洋秋刀鱼主要体征及繁殖特性研究

根据2014年6—7月和10—11月于西北太平洋公海两航次采集的秋刀鱼样本,分析其性别比例、体长和体质量组成、摄食等级,以探究其生长、性腺及繁殖特性。研究结果表明,随着月份的增大,秋刀鱼雌性比例逐渐降低,雄性占比升高;6、7月雌、雄样本优势体长组与体质量组范围均较10、11月小;体长和体质量关系中,秋刀鱼雌性生长系数为3.24,雄性为2.82;各月样本胃饱满度以1级为主,F检验表明,除0级外,4个月内各摄食等级间呈显著差异(P<0.01);秋刀鱼雌、雄样本性腺发育以Ⅱ期为主,各性腺等级间差异不显著(P>0.05),雌性性腺指数在Ⅱ、Ⅲ、Ⅳ期内大于雄性,Ⅴ、Ⅵ期内相反,逻辑斯蒂方程表明,秋刀鱼50%性成熟体长雌性为284.7 mm,雄性为267.4 mm;雌性秋刀鱼绝对繁殖力为1032～17 708粒/尾,平均值为(5522±3196)粒/尾,绝对繁殖力高的个体体长和体质量分别为280～320 mm、110～150 g。

Main Physical Feature and Reproduction Characteristics of Pacific Saury Cololabis saira in the Northwest Pacific Ocean

The sex ratio,body length and body weight composition,feeding grade,growth,gonadal development and reproduction characteristics were investigated in samples of Pacific saury Cololabis saira collected during the two voyages in the Northwest Pacific Ocean from June to July and from October to November in 2014. The results showed that the proportion of female was gradually decreased while the proportion of male increased elapse of month. The ranges of dominant body length and body weight were found to be narrower in June and July than those in October and November with growth coefficient of 3.24 for female and 2.82 for male in the relationship between body length and body weight. F test revealed that there was significant difference in the feeding grades in four months except for grade 0 ( P <0.01),even though the monthly stomach fullness of grade 1 in the most samples. The stage Ⅱ was dominated in the developmental gonads of male and female,without significant difference in each gonadal developmental grade ( P > 0.05 ). However,there was higher gonado-somatic index (GSI)in female with Ⅱ,Ⅲ and Ⅳ stage than that in male with Ⅴ and Ⅵ stage. The Logistic equation indicated that the female had body length of 284.7 mm and male had body length of 267.4 mm when they became maturity at a proportion of 50%,with absolute fecundity from 1032 to 17 708 eggs/individual female,an average of (5522±3196) eggs/individual,absolute fecundity in body length of 290-310 eggs/mm body length and absolute fecundity in body weight of 110-150 g.