Floodplains are generally considered important nursery habitat for young fish, but little information exists regarding the importance of this habitat for Scaphirhynchus sturgeon. During 2019, the lower Missouri River experienced widespread, prolonged floodplain connectivity, and this study provides the first documentation of age-0 Scaphirhynchus sturgeon floodplain prey consumption. Individuals captured on the floodplain primarily consumed chironomids, but the amount of prey consumed was similar to or lower than individuals captured from nearby mainstem reaches and a side-channel during previous years. Similarly, 2019 floodplain sampling often yielded lower age-0 sturgeon condition when assessing length–weight relationships among years. Further downstream, we also analyzed diets from 2019 in two mainstem reaches below Kansas City for comparison with data from 2014 to 2015. In both reaches, 2019 condition was lower than 2014 and 2015 despite a relatively higher growth rate. The amount of prey consumed in 2019 was also similar to or lower than 2014 and 2015 in Glasgow Reach, whereas 2019 yielded the highest prey consumption in Monarch Reach. Our results suggest that the 2019 high-water event did not yield increased prey consumption or condition for age-0 sturgeon on the floodplain, while the findings for mainstem habitats below Kansas City were inconsistent. Overall, empty stomachs were rare regardless of capture location and floodplain individuals appeared to be growing and surviving despite the observed differences. These results address an important information gap for age-0 sturgeon and future data from additional floodplain sites would provide valuable context regarding the applicability of these findings to other areas.

中文翻译：

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密苏里河下游的洪泛区连通性和 0 岁鲟鱼猎物消费

泛滥平原通常被认为是幼鱼的重要育苗栖息地，但关于该栖息地对Scaphirhynchus sturgeon的重要性的信息很少。2019 年，密苏里河下游经历了广泛、长期的洪泛区连通性，这项研究首次提供了 0 岁Scaphirhynchus 的记录鲟鱼以泛滥平原为食。在洪泛区捕获的个体主要食用摇蚊，但消耗的猎物数量与前几年从附近主干河段和侧河道捕获的个体相似或更低。同样，2019 年洪泛区采样在评估年份之间的体长-体重关系时通常会产生较低的 0 龄鲟鱼状况。在更下游，我们还分析了堪萨斯城以下两个主要河段 2019 年的饮食，以与 2014 年至 2015 年的数据进行比较。在这两个河段，尽管增长率相对较高，但 2019 年的状况低于 2014 年和 2015 年。Glasgow Reach 2019 年的猎物消耗量也与 2014 年和 2015 年相似或更低，而 2019 年 Monarch Reach 的猎物消耗量最高。我们的研究结果表明，2019 年的高水位事件并未导致泛滥平原上 0 岁鲟鱼的猎物消耗或状况增加，而堪萨斯城以下主要栖息地的调查结果不一致。总体而言，无论捕获地点如何，空腹都是罕见的，尽管观察到差异，但洪泛区个体似乎仍在成长和生存。这些结果解决了 0 岁鲟鱼的重要信息差距，未来来自其他洪泛区站点的数据将为这些发现对其他地区的适用性提供有价值的背景。无论捕获地点如何，空腹都是罕见的，尽管观察到差异，但洪泛区个体似乎正在成长和生存。这些结果解决了 0 岁鲟鱼的重要信息差距，未来来自其他洪泛区站点的数据将为这些发现对其他地区的适用性提供有价值的背景。无论捕获地点如何，空腹都是罕见的，尽管观察到差异，但洪泛区个体似乎正在成长和生存。这些结果解决了 0 岁鲟鱼的重要信息差距，未来来自其他洪泛区站点的数据将为这些发现对其他地区的适用性提供有价值的背景。