Arai Takaomi, Chino Naoko
Environmental and Life Sciences Programme, Faculty of Science, Universiti Brunei Darussalam, Jalan Tungku Link, Gadong, BE 1410, Brunei Darussalam.
Atmosphere and Ocean Research Institute, The University of Tokyo, 5-1-5, Kashiwanoha, Kashiwa, Chiba 277-8564 Japan.
Heliyon. 2022 May 20;8(5):e09491. doi: 10.1016/j.heliyon.2022.e09491. eCollection 2022 May.
The recent noticeable depletion of the catadromous eel populations has created global concerns for the eel stocks. Thus, the demand for tropical catadromous eels, which are a major alternate target species to compensate temperate species, is sharply increasing. However, eminently little is known regarding the biology and ecology of tropical eels across the Indo-Pacific region. To elucidate the contribution to reproduction among migratory types in a tropical eel, , which is currently considered a major commercial target species, the otolith microchemistry was examined in silver (matured) stage eels. The broad range of otolith Sr:Ca ratios indicated that the habitat use was opportunistic among sea, brackish and fresh waters after recruitment to the continental habitats. Two migratory types, estuarine resident and marine resident eels, were found, but no freshwater resident eel, which is considered as the typical catadromous migration, was found. The lack of freshwater resident eels among all silver eels suggests that the estuarine and marine migrants colonizing adjacent to coastal areas might facilitate a substantial contribution to reproduction for the following generation in this area.
近期降河产卵鳗鱼种群数量显著减少，引发了全球对鳗鱼资源的关注。因此，作为补偿温带鳗鱼的主要替代目标物种，热带降河产卵鳗鱼的需求急剧增加。然而，对于印度-太平洋地区热带鳗鱼的生物学和生态学，人们知之甚少。为了阐明热带鳗鱼（目前被认为是主要商业目标物种）不同洄游类型对繁殖的贡献，对银（成熟）阶段的鳗鱼进行了耳石微化学分析。耳石锶钙比的广泛范围表明，在进入大陆栖息地后，鳗鱼在海洋、咸淡水和淡水环境中的栖息地利用具有机会主义特征。发现了两种洄游类型，即河口定居型和海洋定居型鳗鱼，但未发现被视为典型降河洄游的淡水定居型鳗鱼。在所有银鳗中缺乏淡水定居型鳗鱼，这表明在沿海地区附近定居的河口和海洋洄游型鳗鱼可能对该地区下一代的繁殖做出了重大贡献。
