Different techniques have been employed for fish surveys in freshwater impoundments, however, despite the increasing applicability of underwater video systems for fish sampling in different aquatic ecosystems, such technology has not been tested in reservoirs. This study compares estimates of fish species richness, community composition, and size structure derived from visual census (VC) and underwater video (UWV) in two Neotropical reservoirs. The total number of species recorded by both sampling methods was similar, even though UWV recorded higher mean number of species than VC, in both reservoirs. In general, VC was more efficient in recording cryptic and resident species, while UWV, was better for highly mobile species. Considering size classes, VC was more efficient than UWV in detecting smaller individuals (i.e., 31–79 mm total length). Although observational sampling methods depend on water transparency, UWV can be considered a complementary and promising technique for fish surveys in shallow areas of clear reservoirs.

中文翻译：

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新热带水库鱼类取样目测与水下视频对比

淡水蓄水池中的鱼类调查采用了不同的技术，然而，尽管水下视频系统在不同水生生态系统中进行鱼类采样的适用性越来越强，但此类技术尚未在水库中进行测试。本研究比较了根据视觉普查 (VC) 和水下视频 (UWV) 在两个新热带水库中得出的鱼类物种丰富度、群落组成和大小结构的估计值。两种采样方法记录的物种总数相似，尽管 UWV 在两个水库中记录的物种平均数高于 VC。一般来说，VC 在记录隐蔽和常驻物种方面更有效，而 UWV 对高度流动的物种更好。考虑到尺寸等级，在检测较小个体（即总长度为 31-79 毫米）方面，VC 比 UWV 更有效。