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 of 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 in order 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（stocking）是全球范围内提升并维持商业性与休闲渔业产能的核心管理手段。现有诸多研究已针对该实践对种群与个体遗传混合（admixture）的遗传效应展开探讨，但针对上述过程的驱动因素的相关研究仍较为稀缺。本研究基于对72个未放流与已放流湖泊中的3341条成年湖红点鲑（Salvelinus namaycush）在19个微卫星位点（microsatellite loci）上的基因分型数据，解答了上述科学问题。研究结果显示，相较于未放流种群，已放流种群的遗传多样性显著提升，且种群间遗传分化程度降至原先的一半。已放流种群在种群与个体水平上均表现出显著的遗传混合特征。此外，已放流种群的遗传混合程度与放流强度显著相关，本研究还鉴定出了源种群与放流种群间实现完全遗传同质化的阈值。本研究结果还表明，在特定情景下，人工放流的遗传效应可能仅持续较短时间。综上，本研究揭示了人工放流对已放流种群遗传完整性的显著改变，并强调需进一步明晰遗传混合的驱动因素，以此优化放流策略、保护野生种群的遗传完整性。