Data from: Loss of genetic integrity in wild lake trout populations following stocking: insights from an exhaustive study of 72 lakes from Québec, Canada

Stocking represents the most important management tool worldwide to increase and sustain commercial and recreational fisheries in a context of overexploitation. Genetic impacts of this practice have been investigated in many studies, which examined population and individual admixture, but few have investigated determinants of these processes. Here, we addressed these questions from the genotyping at 19 microsatellite loci of 3341 adult lake trout (Salvelinus namaycush) from 72 unstocked and stocked lakes. Results showed an increase in genetic diversity and a twofold decrease in the extent of genetic differentiation among stocked populations when compared to unstocked. Stocked populations were characterized by significant admixture at both population and individual levels. Moreover, levels of admixture in stocked populations were strongly correlated with stocking intensity and a threshold value of total homogenization between source and stocked populations was identified. Our results also suggest that under certain scenarios, the genetic impacts of stocking could be of short duration. Overall, our study emphasizes the important alteration of the genetic integrity of stocked populations and the need to better understand determinants of admixture to optimize stocking strategies and to conserve the genetic integrity of wild populations.

在渔业资源过度开发的背景下，人工放流是全球范围内用于提升并维持商业性与休闲性渔业产量的核心管理手段。此前诸多研究已针对该实践的遗传影响展开探讨，多聚焦于种群与个体层面的遗传混合，但鲜有研究探究此类过程的驱动因素。本研究基于对72个未放流与放流湖泊中的3341条成年湖鳟（Salvelinus namaycush）在19个微卫星位点（microsatellite loci）的基因分型数据，对上述问题进行了分析。结果显示，相较于未放流种群，放流种群的遗传多样性有所提升，种群间遗传分化程度较未放流种群降低了一半。放流种群在种群与个体层面均表现出显著的遗传混合特征。此外，放流种群的遗传混合程度与放流强度呈显著相关，研究还识别出供体种群与放流种群间实现完全遗传均质化的阈值。本研究结果还表明，在特定场景下，人工放流的遗传影响可能持续时长有限。总体而言，本研究凸显了放流种群遗传完整性所遭受的显著改变，并指出需进一步厘清遗传混合的驱动因素，以优化放流策略、保护野生种群的遗传完整性。