Migrations of juvenile salmon smolts are generally high‐risk, with predation often implicated in reduced survival. In theory, smolts can maximise survival via depensation, or synchronising movements to swamp predators. Depensation, however, is difficult to assess in the wild. Accounting for depensation could also generate more realistic telemetry‐based survival estimates for management. Here, we assess six years (2010–2014, 2016) of acoustic telemetry and outmigration density data for sockeye salmon (Oncorhynchus nerka) from Chilko Lake, British Columbia, Canada. Prevoiusly, depensation for this population wasassessed for a single year, but interannual consistency is not known. We found evidence of depensation in each year, although its strength varied. In addition, by integrating depensation with outmigration densities, annual population‐level survival estimates in this initial (14‐km) migratory segment increased by 0.02–0.24 relative to previously published estimates. However, when extending these survival rates from the first 14 km through the entire tracked migration (1,044 km), increases in estimates were small (~0.01). Potential conservation and management applications of depensation include implications for recovering imperiled populations and informing hatchery release strategies.

中文翻译：

---

鲑鱼迁徙表现出一致的年际掠食性沼泽：对基于遥测的生存估计的影响

鲑鱼幼体的迁徙通常是高风险的，捕食通常会降低生存率。从理论上讲，软体动物可以通过繁殖或与沼泽掠食者同步运动来最大化生存。但是，野外作业很难评估。计帐工作也可以生成更现实的基于遥测的生存估计以进行管理。在这里，我们评估了红鲑鱼（Oncorhynchus nerka）的六年（2010-2014年，2016年）声学遥测和迁移密度数据）来自加拿大不列颠哥伦比亚省奇尔科湖。以前，对该人群的离职时间进行了一年的评估，但年际一致性尚不清楚。尽管强度各不相同，但我们每年都可以找到免税的证据。此外，通过将人口迁移与移民密度结合起来，相对于先前发表的估计值，在此初始（14-km）迁徙阶段的年人口水平的生存估计数增加了0.02-0.24。但是，将这些生存率从最初的14公里扩展到整个追踪的迁徙（1,044公里）时，估计值的增加很小（〜0.01）。养殖场的潜在养护和管理应用包括恢复贫困人口和通知孵化场放养策略。