Abstract

Unlike in nonregulated rivers, new ecological filters are formed in artificial reservoirs: structures (gradient zones between biotopes) which affect the behavior and distribution of juvenile fish and therefore change parameters of the downstream migration. One distinct feature of such filters is their selective effect on different species and age groups of migrants when they pass boundaries between biotopes. The differential transparency of boundaries considerably affects the composition of migrants and dispersal of juvenile fish over biotopes. These suggestions are confirmed by the data of long-term studies on the downstream migration of juvenile Cyprinidae and Percidae in several reservoirs in Eurasia: Sheksna (Sheksna River), Ivankovo (Volga River), Kapchagay (Ili River), and Sarez (Murghab River) Reservoirs. The formation of ecological filters is shown in the zone of wedging-out backwaters (lotic–limnetic transformation) and in the zone between the littoral (resident) and pelagic (migratory) biotopes in the reservoir and in the near-dam broads. Emigration of juveniles from the reservoir depends on the location of the water intake (deep-water or surface) and overlapping of water intake zones with those of the spatial distribution of juvenile fish. The different selectivity of water intake sites of the hydroelectric power station located not far from each other and of a navigation lock forms different (in species and age composition) complexes of emigrants. The mechanisms and consequences of functioning ecological filters and ecological barriers are considered.

中文翻译：

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受管制河流中幼鱼的迁移：生态过滤器的影响（综述）

摘要

与不受管制的河流不同，在人工水库中形成了新的生态过滤器：结构（生物群落之间的梯度带）会影响幼鱼的行为和分布，从而改变下游迁移的参数。此类过滤器的一个独特特征是，当它们经过生物群落之间的边界时，它们对移民的不同物种和年龄组的选择性作用。边界的不同透明度极大地影响了移民的组成以及幼鱼在生物群落上的扩散。这些建议已被关于欧亚大陆几个水库中的鲤科和Per科的下游迁移的长期研究数据所证实，这些水库包括：Sheksna（Sheksna河），Ivankovo（伏尔加河），Kapchagay（伊犁河）和Sarez（Murghab河） ）水库。生态过滤器的形成显示在蓄水的回水区（地层-岩相转换）以及水库和近坝区的滨海（居民）和中上（迁移）生物群落之间的区域。幼鱼从水库中的迁移取决于进水口（深水或地表）的位置以及进水区与幼鱼空间分布的重叠。彼此相距不远的水力发电站的水位和导航船闸的不同选择性形成了不同的（在物种和年龄组成上）移民群。考虑了起作用的生态过滤器和生态屏障的机制和后果。