北部湾多齿蛇鲻繁殖生物学特征

Reproductive biology of Saurida tumbil in the Beibu Gulf

基于2020年在北部湾海域采集的1 214尾多齿蛇鲻(Saurida tumbil)样本,通过对生物学特征和卵巢组织学进行分析,探究该海域多齿蛇鲻种群的繁殖特性及其适应性变化。结果表明,2020年北部湾多齿蛇鲻雌雄性比为1.82∶1,雌性群体成熟性腺四季均有分布,3—8月性成熟系数(Gonad somatic index, GSI)保持较高水平,为主要繁殖期,其中3月和7月为繁殖高峰期;成熟卵巢中存在不同卵径大小的卵粒,卵径组成分布呈明显多峰型;绝对繁殖力波动范围较大(2 774~158 986粒),且成熟卵巢中存在不同发育时相的卵母细胞,综合GSI、繁殖期、卵径分布及组织切片等结果推断多齿蛇鲻为分批非同步产卵型鱼类;相对繁殖力(267粒/g)保持在较高的水平,有利于其在高强度捕捞压力下迅速建立稳定种群;采用Logistic回归方程估算雌性群体的初次性成熟体长为19.0 cm,与性比随体长变化的重要转折点相同。研究发现,北部湾多齿蛇鲻的繁殖特性相较以往结果有所改变,同时,研究结果进一步丰富了北部湾多齿蛇鲻的繁殖生物学资料,为渔业资源保护和可持续利用提供科学参考依据。

Based on 1214 greater lizardfish,Saurida tumbil,collected from the Beibu Gulf in 2020,the reproductive characteristics and its adaptive changes of the population were investigated by assessing the biological characteristics and ovary histology.The results showed that the overall sex ratio of female to male was 1.82∶1,the mature gonads of the female population were distributed in all four seasons,and the gonad somatic index(GSI)remained higher level from March to August,which was the main spawning season with the peak spawning occurring in March and July.Oocytes with different egg diameters were found in the mature ovaries,and obviously multi-modal type was showed in the distribution of egg diameters.The range of absolute fecundity was large(2774–158986),and there were oocytes at different developmental stages in the mature ovaries.Based on the results of GSI,spawning season,oocyte diameter distribution and histological sections,it is concluded that S.tumbil belongs to the non-synchronized multiple batch spawner.The relative fecundity(267 eggs/g)was maintained at a higher level,which was conducive to establishing a stable population rapidly under the high intensity fishing pressure.The estimated body length at the first sexual maturity(L50)for females(19.0 cm)was the same as the body length of the important turning point of the sex ratio.In this study,it was found that the reproductive characteristics of S.tumbil in the Beibu Gulf had difference compared with the previous population.The results further enriched the reproductive biological data available for S.tumbil and provided a scientific basis for the protection and sustainable utilization of S.tumbil resources in the Beibu Gulf.