Despite the large number of dams in most important rivers of Brazil, little is known about fish vertical distribution in neotropical reservoirs, especially deep ones. This study aims to understand how fish were vertically distributed in the deepest reservoir in Brazil, located in the Jequitinhonha River. Three areas of the reservoir were sampled quarterly using an echosounder. The deepest fish detected was at 115 m, but most were shallower than 25 m. Diel vertical migration of fish was detected, but not in all the sampling areas and campaigns. Fish distribution was determined by several limnological factors of the reservoir, but mainly by thermal variation in water column. These results can provide guidance for environmental and fisheries managers and ecologists to improve sampling techniques in deep reservoirs since vertical distribution and its relation with habitat use are determinant to propose management measures in similar ecosystems.

中文翻译：

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巴西最深水库鱼类的垂直分布

尽管巴西最重要的河流中有大量水坝，但人们对新热带水库，尤其是深水库中鱼类的垂直分布知之甚少。本研究旨在了解鱼类在巴西最深水库中的垂直分布情况，该水库位于 Jequitinhonha 河。使用回声测深仪每季度对水库的三个区域进行采样。探测到的最深的鱼在 115 m，但大多数都比 25 m 浅。检测到鱼类的昼夜垂直洄游，但并非在所有采样区域和活动中都检测到。鱼类分布由水库的几个湖泊学因素决定，但主要由水柱的热变化决定。