Habitat use and habitat transitions in the tropical eel, Anguilla bicolor bicolor
Habitat use and habitat transitions in the tropical eel, Anguilla bicolor bicolor
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DOI：
10.1007/s10641-010-9677-y
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发表时间：
2010-12-01
影响因子：
1.4
通讯作者：
Arai, Takaomi
中科院分区：
文献类型：
--
作者：
Chino, Naoko;Arai, Takaomi
近年来，人们利用微量化学分析技术对温带鳗鱼的迁徙历史进行了深入的研究，以确定耳石中锶与钙的比值(锶：钙)。然而，关于热带鳗鱼物种的这一性质的研究很少。为了阐明淡水鳗属的迁徙生态，以及其生活史和栖息地的用途，我们研究了印度尼西亚水域采集的热带双色鳗耳石中锶和钙的浓度。在泻湖地区采集的双色沙棘中，高锶：钙核心以外的锶/钙比值的变化显示出两种栖息地利用模式：(1)持续生活在没有淡水生活的咸水或海水中(居民，37%)；(2)栖息地从淡水转移到咸水或海水(候鸟，63%)。对于迁徙鱼类，大多数鱼的栖息地从耳石核心转移到520-950亩(平均740亩)之间。这些转变表明这些标本迁移到了更高盐度的环境中。双色黄鳗耳石的锶钙比范围很大(距全部耳石中心150亩以外的所有分析点均为0.02×10~(-3)~12.79×10~(-3))，表明热带鳗鱼在沿海淡水、微咸水和海水中的栖息地利用是兼性的。这种灵活的栖息地使用与温带鳗鱼相同。因此，鳗鱼迁徙到淡水中显然不是强制性行为。
Recently, the migratory history of temperate species of anguillid eels has been intensively studied using analytical microchemical techniques to determine the ratios of strontium to calcium (Sr:Ca) in the otoliths. However, there have been few studies of this nature on tropical anguillid eel species. To elucidate the migration ecology of the freshwater eel genus Anguilla, as well as its life history and habitat use, we examined the otolith Sr and Ca concentrations of a tropical anguillid eel Anguilla bicolor bicolor collected in Indonesian waters. In A. bicolor bicolor collected in a lagoon area, the change in Sr:Ca ratios outside the high Sr:Ca core showed two patterns of habitat use, (1) constantly living in either brackish or sea waters with no freshwater life (residents, 37%), and (2) habitat shift from freshwater to brackish or sea waters (migrants, 63%). For migrant fishes, most fish shifted their residence between 520 and 950 mu m (mean: 740 mu m) from the otolith core. These transitions suggest that these specimens moved to a higher salinity environment. The wide range of otolith Sr:Ca ratios (0.02 x 10(-3) to 12.79 x 10(-3) in all analytical points outside of 150 mu m from the core of all otoliths) in A. bicolor bicolor indicated that the habitat use of the tropical eel was facultative among fresh, brackish and marine waters during their growth phases after recruitment to the coastal areas. This flexible habitat use was the same as that of temperate eels. Thus, the migrations of anguillid eels into freshwater is clearly not an obligatory behavior.