Shovelnose Sturgeon Scaphirhynchus platorynchus were extirpated from the Bighorn River, Wyoming during the 20th century after the construction of two main-stem dams and the resulting modifications to fish passage and flow and thermal regimes. The species was reintroduced to the river between 1996 and 2020, but nothing was known about how these fish used the river and whether they could sustain themselves without consistent stocking. Radio telemetry during 2015–2018 identified at least two putative spawning locations 95.6 and 139.5 river kilometers upstream from a reservoir transition zone. Temperature and velocity data suggest that most of the drifting larvae will have insufficient fluvial habitat to complete their drift stage and are likely to enter the Bighorn Lake transition zone. Benthic dissolved oxygen concentrations in the reservoir transition zone were low enough to cause recruitment reduction or failure for drifting larvae that reach this habitat. Future monitoring will determine whether this population persists, but this study highlights the importance of understanding species life history and the causes of extirpations to better predict reintroduction success.

中文翻译：

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怀俄明州比格霍恩河重新引入的铲鼻鲟种群的自然补充潜力

铲鼻鲟Scaphirhynchus platorynchus20 世纪，在建造了两座主干水坝以及对鱼类通道、水流和热状况进行了修改后，它们从怀俄明州的比格霍恩河中灭绝。该物种在 1996 年至 2020 年间被重新引入河流，但人们对这些鱼如何利用河流以及它们是否可以在没有持续放养的情况下维持生计一无所知。2015-2018 年期间的无线电遥测确定了至少两个假定的产卵地点，位于水库过渡区上游 95.6 和 139.5 河流公里处。温度和速度数据表明，大多数漂流幼虫的河流栖息地不足以完成其漂流阶段，很可能进入比格霍恩湖过渡带。水库过渡区的底栖溶解氧浓度低到足以导致到达该栖息地的漂流幼虫的补充减少或失败。未来的监测将确定该种群是否持续存在，但这项研究强调了了解物种生活史和灭绝原因以更好地预测重新引入成功的重要性。