Environmental and Life Sciences Programme, Faculty of Science, Universiti Brunei Darussalam, Jalan Tungku Link, Gadong, BE 1410, Brunei Darussalam.
Institute of Oceanography and Environment, Universiti Malaysia Terengganu, 21030 Kuala Terengganu, Terengganu, Malaysia.
Sci Rep. 2017 Jan 30;7:41649. doi: 10.1038/srep41649.
Information on the spawning migration, spawning ecology and life history of tropical eels in the Indo-Pacific region is very limited. The physiological and morphological characteristics of tropical freshwater eels, Anguilla bicolor bicolor and A. bengalensis bengalensis collected in Malaysia were examined in relation to their downstream migration patterns. A total of 455 eels were collected over monthly intervals between February 2014 and January 2016 and we examined both gonadosomatic index and gonad histology features. In both species, close positive relationships between advanced maturation stages and eye, fin, gonadosomatic indexes were found in males and females. A. bengalensis bengalensis was found to be larger and heavier than A. bicolor bicolor at the time of seaward migration. The final stage of maturation for seaward spawning migration occurred throughout the year in A. bicolor bicolor, although that of A. bengalensis bengalensis was estimated to six months due to the limited number of samples. These results suggest that year-round spawning in the open ocean occurs in the tropical eel. This non-seasonal spawning ecology is notably different from that of temperate eels, which are known to follow a well-defined spawning season, with spawning migrations generally taking place during autumn months.
有关印度洋-太平洋地区热带鳗鲡的产卵洄游、产卵生态学和生活史的信息非常有限。本研究采集了 2014 年 2 月至 2016 年 1 月期间每月间隔采集的马来西亚热带淡水鳗鲡（双色鳗鲡和孟加拉鳗鲡）共 455 尾，分析了它们的下行洄游模式，并研究了其生理和形态特征。在雌雄两性中，成熟阶段的高级别与眼睛、鳍和性腺体指数之间均存在密切的正相关关系。在向海洄游时，孟加拉鳗鲡的体型和体重均大于双色鳗鲡。尽管由于样本数量有限，估计孟加拉鳗鲡的产卵洄游期为 6 个月，但在双色鳗鲡中，全年都存在向海产卵的最终成熟阶段。这些结果表明，热带鳗鲡在开阔海域中全年产卵。这种非季节性的产卵生态学与温带鳗鲡明显不同，温带鳗鲡的产卵洄游期通常在秋季进行，具有明确的产卵季节。
