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.

在全球渔业资源过度开发的背景下，人工放养（stocking）是提升并维系商业性与休闲渔业产能的核心管理手段。已有诸多研究针对该实践的遗传影响展开探讨，聚焦种群与个体层面的遗传混合（admixture），但鲜有研究关注此类过程的影响决定因素。
本研究基于采自72个未放养与已放养湖泊的3341条成年湖鳟（Salvelinus namaycush）在19个微卫星位点（microsatellite loci）的基因分型（genotyping）数据，对上述问题展开探究。研究结果显示，相较于未放养种群，已放养种群的遗传多样性有所提升，种群间遗传分化程度降低了一半。已放养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，已放养种群的遗传混合程度与放养强度显著相关，研究还鉴定出源种群与放养种群间实现完全遗传均质化的阈值。本研究结果还提示，在特定情景下，人工放养的遗传影响可能仅持续较短时长。
总体而言，本研究凸显了人工放养对种群遗传完整性的显著破坏，同时强调亟需深入解析遗传混合的影响决定因素，以优化放养策略并保护野生种群的遗传完整性。