Data from: Resurrecting an extinct salmon evolutionarily significant unit: archived scales, historical DNA, and implications for restoration

Archival scales from 603 sockeye salmon (Oncorhynchus nerka), sampled from May to July 1924 in the lower Columbia River, were analyzed for genetic variability at 12 microsatellite loci, and compared to 17 present-day O. nerka populations—exhibiting either anadromous (sockeye salmon) or non-anadromous (kokanee) life histories—from throughout the Columbia River Basin, including areas upstream of impassable dams built subsequent to 1924. Statistical analyses identified four major genetic assemblages of sockeye salmon in the 1924 samples. Two of these putative historical groupings were found to be genetically similar to extant evolutionarily significant units (ESUs) in the Okanogan and Wenatchee rivers (pairwise FST = 0.004 and 0.002, respectively) and assignment tests were able to allocate 77% of the fish in these two historical groupings to the contemporary Okanogan River and Lake Wenatchee ESUs. A third historical genetic grouping was most closely aligned with contemporary sockeye salmon in Redfish Lake, Idaho, although the association was less robust (pairwise FST = 0.060). However, a fourth genetic grouping did not appear to be related to any contemporary sockeye salmon or kokanee population, assigned poorly to the O. nerka baseline, and had distinctive early return migration-timing suggesting that this group represented a putative historical ESU originating in headwater lakes in British Columbia that was likely extirpated sometime after 1924. The lack of a contemporary O. nerka population possessing the genetic legacy of this extinct ESU indicates that efforts to reestablish early-migrating sockeye salmon to the headwater lakes region of the Columbia River will be difficult.

本数据集涵盖1924年5月至7月于哥伦比亚河下游采集的603份红大马哈鱼（sockeye salmon，Oncorhynchus nerka）的归档鳞片样本，对其12个微卫星位点（microsatellite loci）的遗传变异进行分析，并与哥伦比亚河流域全域（含1924年后修建的不可逾越大坝上游区域）的17个现存O. nerka种群进行比对；这些现存种群兼具溯河洄游型（红大马哈鱼）与陆封型（科卡尼鲑，kokanee）两种生活史类型。
统计分析显示，1924年的样本中可划分为4个主要的红大马哈鱼遗传集群。其中2个推定的历史种群集群，与奥卡诺根河与韦纳奇河的现存进化显著单元（evolutionarily significant units, ESU）遗传相似度极高，成对固定指数（pairwise FST）分别为0.004与0.002；个体归属测试可将这2个历史集群中77%的个体，归至当代奥卡诺根河与韦纳奇湖的ESU中。
第三个历史遗传集群，与爱达荷州雷德菲什湖的现存红大马哈鱼亲缘关系最近，但该关联的支持度相对较弱（成对FST=0.060）。
然而，第四个遗传集群未发现与任何现存红大马哈鱼或科卡尼鲑种群存在遗传关联，对O. nerka遗传基准数据库的归属度极低，且具有独特的早期洄游返巢时间特征，表明该集群代表了一个起源于不列颠哥伦比亚省源头湖泊的推定历史ESU，该类群大概率在1924年后的某一时间点发生局域灭绝。
目前尚未发现携带该灭绝ESU遗传遗产的现存O. nerka种群，这意味着将早期洄游型红大马哈鱼重新引入哥伦比亚河源头湖泊区域的工作将面临极大挑战。