Downstream migration of silver-phase anguillid eels
Downstream migration of silver-phase anguillid eels
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银相鳗鱼的下游洄游
DOI：
10.1007/978-4-431-65907-5_15
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发表时间：
2003
期刊：
影响因子：
--
通讯作者：
A. Haro
中科院分区：
文献类型：
--
作者：
A. Haro
淡水栖息地的成年鳗鱼的下游迁移标志着一个漫长的，一般缓慢的增长阶段的结束，放弃了一个家庭的范围，并开始向海产卵迁移。虽然不同种类的Anguilla表现出变化的特点，这一迁移阶段，一些广义的特点，在迁移是共同的大多数物种。对于温带和亚热带物种ofAnguilla，洄游期通常与一年中水温下降和流量增加的时间有关。北方半球的安圭拉物种通常在8月至12月间迁徙，而南半球的安圭拉物种在1月至3月间离开淡水栖息地。在北方，A.在高纬度地区，喙层鱼的迁徙时间较早（图1）。Tesch（1977）认为，A.安圭拉不能仅仅根据地理来预测。银迁移期的开始在大多数种类的安圭拉中通常具有形态学特征，如背表面和鳍边缘变暗，侧珠被镀银，眼睛直径扩大，以及性腺发育增加（Lecomte-Finiger 1990）。其他内分泌变化也发生在变态期间（Durif等人，2000年）。
Downstream migration of adult anguillid eels in freshwater habitats marks the end of a long, generally slow growth phase, abandonment of a home range, and initiation of a seaward spawning migration. Although different species ofAnguillaexhibit variation in characteristics of this migratory phase, some generalized traits in migration are common to most species. For temperate and subtropical species ofAnguilla,migratory periods are usually associated with times of year when water temperatures are decreasing and flows are increasing. Species ofAnguillain the northern hemisphere usually emigrate between the months of August and December, while those of the southern hemisphere leave freshwater habitats between January and March. In the northern hemisphere,A. rostratatends to emigrate earlier at higher latitudes (Fig. 1). However, Tesch (1977) concluded that the migration date ofA. anguillacould not be predicted on the basis of geography alone. Onset of the silver migratory phase is generally morphologically characterized in most species ofAnguillaas a darkening of dorsal surfaces and fin margins, silvering of lateral integument, enlargement of eye diameter, and an increase in gonad development (Lecomte-Finiger 1990). Other endocrinological changes also occur during metamorphosis (Durif et al. 2000).