Accurate estimates of salmonids passing Lower Granite Dam on the Snake River, by species and origin, are a critical input to assessing the status and trends of various populations as well as successful management of fisheries in the Snake River basin. Here, we describe a state-space model that estimates such escapement past a dam by using window counts, PIT tag observations, and data from an adult fish trap, accounting for issues such as nighttime passage, fallback and reascension, potential observation error at the window, and uncertainty in the adult trap rate. We tested the approach using a simulation framework that mimicked several levels of observation error, differences between nighttime passage and reascension rates, and the possibility of the adult trap being closed for some period of time. Our results demonstrate that the model produced unbiased estimates across all tested scenarios. We also applied this model to empirical data from Lower Granite Dam to produce estimates of wild, clipped hatchery, and unclipped hatchery spring/summer-run Chinook Salmon Oncorhynchus tshawytscha and steelhead O. mykiss from spawn years 2010–2019.

中文翻译：

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使用多个数据源估计鲑鱼逃逸的状态空间模型

按物种和来源对通过蛇河下游花岗岩大坝的鲑鱼的准确估计是评估蛇河流域各种种群状况和趋势以及渔业成功管理的关键输入。在这里，我们描述了一个状态空间模型，该模型通过使用窗口计数、PIT 标记观察和来自成鱼陷阱的数据来估计这种越过大坝的擒纵装置，并考虑了诸如夜间通过、回落和重新上升、在窗口，以及成人诱捕率的不确定性。我们使用模拟框架测试了该方法，该框架模拟了几个级别的观察误差、夜间通过和重新扬升率之间的差异，以及成人陷阱关闭一段时间的可能性。我们的结果表明，该模型在所有测试场景中都产生了无偏估计。我们还将这个模型应用于下花岗岩大坝的经验数据，以估计野生、修剪孵化场和未修剪孵化场春季/夏季运行的奇努克鲑鱼Oncorhynchus tshawytscha和 steelhead O. mykiss产卵期为 2010-2019。