Adult Pacific salmon Oncorhynchus spp. undertake energetically demanding migrations where they must have adequate energy reserves to survive to reach spawning locations and reproduce. Lethal proximate analysis provides insight into available energy stores (e.g., lipids), but the ability to monitor energetic status nonlethally may be useful for managers. Nonlethal monitoring may be more cost effective, reduce harm to sensitive populations, allow for more fish to be sampled, and assessments can be done relatively quickly. Chinook Salmon Oncorhynchus tshawytscha (N = 129) were sampled for proximate analysis from four populations in Alaska to examine variation in energetic status before and after spawning migration and to create predictive bioelectrical impedance analysis (BIA) models for this species. In addition to proximate analysis we tested the variability between two BIA devices (Q2 and CQR), whether BIA models were generalizable to a congener, Chum Salmon Oncorhynchus keta, and the feasibility of integrating BIA into field studies. The populations that were sampled at prespawning migration had higher %lipid (N = 77; mean = 43%) than those that were collected at postspawning migration (N = 52; mean = 20%). Total %lipid and %water was more accurately predicted based on BIA measurements that were made by using the Q2 device (RMSE = 5.33 and RMSE = 2.43, respectively) than on those that were made by using the CQR device measurements (RMSE = 6.27; RMSE = 2.66). The between‐species (Chinook Salmon to Chum Salmon RMSE = 19.47; Chum to Chinook RMSE = 7.69) models were less accurate than species‐specific models that were created for Chinook Salmon and Chum Salmon, suggesting that single‐species models should be used. We field‐tested the BIA model to predict %lipid and %water for Chinook Salmon on a remote Southeast Alaska river. The range of predicted values of %lipid and %water was similar to the results that are obtained via proximate composition from the other populations. Our results indicate that BIA could be a valuable tool for assessing the spatial and temporal patterns of energetic status for Chinook Salmon populations.

中文翻译：

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阿拉斯加奇努克鲑鱼的活力状态：种群之间的比较和使用生物电阻抗分析的预测模型。

成年太平洋鲑鱼Oncorhynchus spp。进行能源要求苛刻的迁徙，他们必须有足够的能量储备才能生存到产卵地并繁殖。致命的最近分析可以深入了解可用的能量存储（例如脂质），但是非致命性地监测精力充沛状态的能力可能对管理人员有用。非致命性监测可能更具成本效益，可以减少对敏感种群的危害，可以对更多鱼类进行采样，并且可以相对快速地进行评估。奇努克鲑鱼Oncorhynchus tshawytscha（N  = 129）从阿拉斯加的四个种群中取样进行近期分析，以检查产卵迁移前后的能量状态变化，并为该物种建立预测性生物电阻抗分析（BIA）模型。除了进行近距离分析外，我们还测试了两个BIA设备（Q2和CQR）之间的变异性，BIA模型是否可推广到同类动物Chum Salmon Oncorhynchus keta以及将BIA集成到现场研究中的可行性。产卵前迁徙时采样的种群的脂类含量较高（N  =  77；平均值= 43％），高于产卵后迁徙所采集的种群（N  = 52; 平均值= 20％）。根据使用Q2装置进行的BIA测量（分别为RMSE = 5.33和RMSE = 2.43），比使用CQR装置进行的BIA测量（RMSE = 6.27；更准确地预测总脂质和％水分）。 RMSE = 2.66）。种间模型（奇努克鲑鱼至大马哈鱼RMSE = 19.47;奇姆鲑鱼至奇努克RMSE = 7.69）比为奇努克鲑鱼和大马哈鱼创建的特定物种模型的准确性较差，建议应使用单物种模型。我们对BIA模型进行了现场测试，以预测遥远的阿拉斯加东南部奇努克鲑鱼的脂质和％水分。％脂质和％水的预测值的范围类似于通过其他人群的近似组成获得的结果。