基于线粒体DNA控制区序列的短棘鲾群体遗传学

物种的遗传结构对推断群体历史动态如有效群体大小、地理分布变迁、基因流、遗传分化等具有重要意义。本实验采用线粒体DNA控制区高变区序列对采自我国海南和台湾的3个短棘鲾群体进行了遗传学比较研究。结果显示,92尾个体共检测到32个单倍型,其中共享单倍型7个;单倍型多样性指数的范围为0.61±0.12～0.86±0.05;核苷酸多样性指数的范围为0.003 3±0.002 4～0.005 3±0.003 4;32个单倍型构建的邻接关系树和最小跨度树均可分为2个单倍型类群,单倍型类群A共有22个单倍型,全部由海南文昌和三亚新村群体构成,单倍型类群B共有10个单倍型,除Hap13外,其余全部由台湾新竹群体构成;台湾新竹群体与海南2个群体之间存在显著差异,但海南文昌群体和三亚新村群体之间无显著差异;中性检验与核苷酸不配对分布分析的结果均显示,短棘鲾2个单倍型类群可能发生了群体扩张事件,扩张时间分别为52 500～105 000和67 600～135 200年前。     

Reproductive biology of the common ponyfish <Emphasis Type="Italic">Leiognathus equulus</Emphasis> in the south-western waters off Taiwan

ABSTRACT:   Reproductive biology of the common ponyfish Leiognathus equulus was described based on 958 specimens caught by otter trawlers in the south-western waters off Taiwan and landed at Tungkang and Linuan fishing ports from March 2000 to February 2001. Macroscopic appearance of the ovary, gonad-somatic index, oocyte diameter frequency distribution, and histological examination suggested that the spawning season of the common ponyfish in south-western Taiwan waters is from May to August. Eight stages of oocyte development were determined based on histological examination, and ovarian development can be divided as immature, early maturing, late maturing, mature and spent stages. The sex ratio of 0.52 was not significantly different from 0.5 using χ² test, but females were overwhelmingly more when fork length (FL) was greater than 170 mm. The relations between fecundity (F), batch fecundity (BF), and body weight (BW) were estimated to be F =−5328 + 1.2946 BW ( n  = 132, P  < 0.05) and BF = −11.26 + 0.2748 BW ( n  = 25, P  < 0.05), respectively. Mean fecundity and mean batch fecundity (± standard error) were estimated to be 129 955 ± 79 343 and 28 160 ± 14 698, respectively. Sizes at 50% maturity estimated from the Logistic model were 162 mm FL and 158 mm FL for females and males, respectively.