Barge transportation of steelhead Oncorhynchus mykiss smolts through the Snake and Columbia rivers can increase the probability of straying by returning adults at the individual scale. However, the effect of barge transportation on a major population group has not been evaluated. We estimated the proportion of hatchery‐origin steelhead spawners present in the John Day River from 2004 to 2018 via observation of adults on spawning ground surveys and in traps. Despite no hatchery releases within the John Day River, up to 42% of the observed spawners in nature were of hatchery origin. The proportion of hatchery‐origin spawners in the John Day River was best explained by the number of smolts that were barge transported from the Snake River 2–3 years prior to spawning and natural‐origin spawner abundance. At an individual scale, barged hatchery steelhead from the Snake River, when compared with hatchery and wild steelhead that were allowed to migrate in‐river as smolts, were 73 times more likely to be detected in the John Day River during their adult return migration. Barged hatchery and barged wild steelhead exhibited no difference in the probability of adult detection in the John Day River. Our study demonstrates how a salmonid recovery effort in one portion of the Columbia River basin had an unintended and potentially adverse impact on non‐target populations. To minimize stray spawners (both hatchery and wild) in the John Day River, transportation of Snake River steelhead smolts should replicate spawning years 2013–2018 (i.e., the 2010–2016 smolt cohorts), with transportation not beginning until May 1 and with the total number of transported hatchery smolts maintained at a level no greater than 2.3 million annually.

中文翻译：

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mol运输影响野生和孵化场蛇河斯蒂尔黑德向约翰·戴特河的逃亡

昂首鱼Oncorhynchus mykiss的驳船运输通过Snake和Columbia河的大虫可以通过成年个体返回成年后增加流浪的可能性。但是，驳船运输对主要人口群体的影响尚未得到评估。通过对产卵场调查和陷阱中的成虫进行观察，我们估算了约翰·戴河（John Day River）在2004年至2018年间孵化场产的硬头鲨鱼产卵场的比例。尽管约翰·戴特河（John Day River）内没有孵化场，但自然界中观察到的产卵者中有多达42％是孵化场起源的。约翰代河（John Day River）中孵化场产卵场的比例最好用产卵前2-3年从斯内克河（Snake River）运来的mol鱼数量和天然产卵场的丰富性来最好地解释。在个体规模上，来自斯内克河（Snake River）的带刺孵化场的孵化场，与孵化场和野生硬头鱼被允许以鲑鱼的形式迁徙相比，在约翰·戴特河成年后的迁徙过程中被发现的可能性要高73倍。约翰·戴河（John Day River）的带刺孵化场和带刺野生​​野性黑头鱼的成年检出率没有差异。我们的研究表明，哥伦比亚河流域一部分地区鲑鱼的恢复工作如何对非目标人群产生意料之外的潜在影响。为了最大程度地减少约翰·戴特河的流浪产卵场（孵化场和野生场），Snake River硬头head鱼的运输应复制2013-2018年的产卵年（即2010-2016年的mol鱼队列），直到5月1日才开始运输，每年运输的孵化场小白鹭总数保持在不超过230万的水平。