Data from: Sockeye salmon repatriation leads to population re-establishment and rapid introgression with native kokanee

Re-establishing salmonid populations to areas historically occupied has substantial potential for conservation gains, however, such interventions also risk negatively impacting native resident stocks. Here, we assessed the success of the hatchery-assisted reintroduction of anadromous sockeye salmon (Oncorhynchus nerka) into Skaha Lake, British Columbia, Canada, and evaluated the genetic consequences for native kokanee, a freshwater-obligate ecotype, using single nucleotide polymorphism genotypic data collected from reference samples of spawning Okanagan River sockeye and Skaha Lake kokanee pre-sockeye reintroduction, along with annual trawl survey and angler-caught samples obtained over an eight-year period. Significant differentiation was detected between sockeye and kokanee reference samples, with >99% stock assignment. Low proportions of sockeye and hybrids were detected within 2008 and 2010 age-0 trawl samples, however, by 2012, 28% were sockeye, rising to 41% in 2014. The number of hybrids detected rose proportionally with the increase in sockeye, and exhibited an intermediate phenotype. Our results indicate that reintroduction of anadromous sockeye to Skaha Lake is succeeding, with large numbers returning to spawn. However, hybridization with native kokanee is of concern due to the potential for demographic or genetic swamping, with on-going genetic monitoring necessary to assess the long-term effects of introgression and to support interactive fisheries management.

将鲑科鱼类种群重建至其历史分布区域，对物种保护具有可观的增益潜力，但此类干预措施也可能对本地定居种群造成负面影响。本研究针对加拿大不列颠哥伦比亚省斯卡哈湖开展的孵化场辅助溯河产卵红大马哈鱼（Oncorhynchus nerka）再引入项目的成效进行评估，并针对作为淡水专性生态型的本地科卡尼鲑（kokanee）的遗传影响展开分析。研究采用两类基因分型数据：一是红大马哈鱼再引入前，产卵期奥卡诺根河红大马哈鱼与斯卡哈湖科卡尼鲑的参考样本的单核苷酸多态性（single nucleotide polymorphism）基因分型数据；二是八年期间逐年收集的拖网调查与垂钓捕获样本的对应数据。参考样本分析显示，红大马哈鱼与科卡尼鲑之间存在显著遗传分化，种群归属判定准确率超过99%。2008年与2010年的0龄幼鱼拖网样本中，仅检测到少量红大马哈鱼个体与杂交个体；但到2012年，红大马哈鱼个体占比达28%，2014年进一步升至41%。检测到的杂交个体数量随红大马哈鱼种群占比提升呈比例增长，且表现出中间表型。本研究结果表明，斯卡哈湖溯河产卵红大马哈鱼的再引入项目已取得成功，大量个体洄游至该湖产卵。但与本地科卡尼鲑的杂交现象值得关注，因为这可能引发种群数量或遗传物质的淹没效应，因此需开展持续的遗传监测，以评估基因渐渗的长期影响，并辅助交互式渔业管理。