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.

将鲑科鱼类种群重新引入其历史分布区域，在物种保护方面具备可观的应用潜力，但此类干预措施亦存在对本土定居种群造成负面影响的风险。本研究针对加拿大不列颠哥伦比亚省斯卡哈湖开展的人工繁育辅助溯河产卵红大马哈鱼（Oncorhynchus nerka）重新引入项目的成效进行了评估，并针对本土专性淡水生态型科卡尼鲑（kokanee）的遗传影响展开分析。研究采用的遗传数据包括红大马哈鱼重新引入前的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, SNP）基因型数据，以及为期8年的年度拖网调查与垂钓捕获样本。结果显示，红大马哈鱼与科卡尼鲑的参考样本间存在显著遗传分化，种群归属鉴定准确率超过99%。2008年与2010年的0龄组拖网样本中，红大马哈鱼与杂交个体的占比极低；但到2012年，红大马哈鱼个体占比已达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，且表现出中间表型特征。本研究结果表明，溯河产卵红大马哈鱼在斯卡哈湖的重新引入项目已取得成功，大量个体洄游至该湖产卵。但需警惕其与本土科卡尼鲑的杂交现象，因为该过程可能引发种群替代或遗传淹没风险，因此需开展持续的遗传监测，以评估基因渐渗的长期影响，并为互动式渔业管理提供支撑。