The movement patterns of native migratory fishes may reflect different selection pressures in different environments that are associated with predictable patterns of temperature and discharge. Spatial and temporal variability in the movement patterns of adult Coho Salmon Oncorhynchus kisutch were explored with data that were collected from the Umpqua River basin, Oregon, focusing on two points in their return migration: (1) main‐stem midriver migration timing of adult Coho Salmon as they pass Winchester Dam, Oregon, and (2) adult spawn timing in tributary streams of the Smith River. Main‐stem migration of Coho Salmon as they pass Winchester Dam began 7 to 15 d after peak annual water temperature, when mean daily temperatures cooled to 18°C, but before the increases in discharge that are associated with autumn rains. Although migration timing appeared to be strongly related to river temperature, spawn timing of Coho Salmon in tributaries of the Smith River subbasin appeared to respond to a combination of both discharge and temperature thresholds. Spawning occurred after initial annual peak discharge events and when stream temperatures fell below a threshold of 12°C. These results directly inform water conservation and protection planning for environmental flow criteria and thermal ranges during migration and spawn timing of imperiled Coho Salmon in the Oregon Coast Range.

中文翻译：

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俄勒冈Umpqua流域河水流量和温度差异对银大麻哈鱼迁移和产卵时机的影响

本地迁徙鱼类的移动方式可能反映了在不同环境中与温度和流量的可预测方式相关的不同选择压力。成年Coho鲑Oncorhynchus kisutch的运动方式的时空变化使用从俄勒冈州乌姆普夸河流域收集的数据进行了探索，重点研究了回迁的两个点：（1）成年Coho鲑鱼经过俄勒冈州温彻斯特大坝时，其主干微动子迁移时机，以及（2）成年鲑在史密斯河的支流中产卵的时间。当Coho鲑鱼通过温彻斯特大坝时，其主干迁移开始于年度水温峰值之后的7至15 d，那时年平均温度降到18°C，但在与秋季降雨相关的流量增加之前。尽管迁移时间似乎与河水温度密切相关，但史密斯河流域支流中的Coho Salmon产卵时间似乎对流量和温度阈值的组合都有反应。产卵发生在最初的年度峰值排放事件之后，并且溪流温度降至12°C以下时。这些结果直接为在俄勒冈海岸山脉受威胁的Coho鲑鱼迁移和产卵时的环境流量标准和热范围提供了节水和保护的规划。