1. Large-scale movement of fishes is a challenge for conservation and management in rivers, especially when individuals can cross jurisdictional boundaries.
2. Assessing large-scale movement is particularly difficult during early life stages, especially when endangered species are involved. After hatching, free embryos of the federally endangered pallid sturgeon (Scaphirhynchus albus) drift long distances during development. Following the transition to exogenous feeding, individuals may continue to move downstream, resulting in a potential two-step migration.
3. Tagged age-0 pallid sturgeon were stocked into the lower Missouri River, which provided an opportunity to assess pallid sturgeon dispersal as well as the hypothesized two-step migration. From July 2018 to April 2021, 79 individuals were captured, with most dispersing 200–800 km downstream from the stocking location.
4. The observed dispersal of pallid sturgeon supports the two-step downstream migration hypothesis. This migration may lead to dispersal into the Mississippi River, which highlights the need for expanded monitoring into the Mississippi River for an effective evaluation of pallid sturgeon recovery actions. This study also reinforces the importance of inter-jurisdictional management and collaboration to better account for the large-scale movement of river fishes.

中文翻译：

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评估濒危鱼类的大规模移动：密苏里河下游放养的 0 岁苍白鲟鱼的散布

1. 鱼类的大规模移动是河流保护和管理的挑战，尤其是当个人可以跨越管辖边界时。
2. 在生命早期阶段评估大规模移动尤其困难，尤其是在涉及濒危物种时。孵化后，联邦濒临灭绝的苍白鲟（Scaphirhynchus albus）的游离胚胎在发育过程中会漂移很长一段距离。在转向外源喂养后，个体可能会继续向下游移动，从而导致潜在的两步迁移。
3. 标记为 0 岁的苍白鲟被放养在密苏里河下游，这为评估苍白鲟的扩散以及假设的两步迁移提供了机会。从 2018 年 7 月到 2021 年 4 月，共捕获了 79 只个体，大多数分布在放养地点下游 200-800 公里处。
4. 观察到的苍白鲟鱼的扩散支持了两步下游迁移假说。这种迁移可能会导致扩散到密西西比河，这凸显了扩大对密西西比河的监测以有效评估苍白鲟鱼恢复行动的必要性。这项研究还强调了跨辖区管理和合作的重要性，以更好地解释河流鱼类的大规模移动。