Data from: Genetic and phenotypic changes in an Atlantic salmon population supplemented with non-local individuals: a longitudinal study over 21 years

While introductions and supplementations using non-native and potentially domesticated individuals may have dramatic evolutionary effects on wild populations, few studies documented the evolution of genetic diversity and life-history traits in supplemented populations. Here, we investigated year-to-year changes from 1989 to 2009 in genetic admixture at 15 microsatellite loci and in phenotypic traits in an Atlantic salmon (Salmo salar) population stocked during the first decade of this period with two genetically and phenotypically distinct source populations. We detected a pattern of temporally increasing introgressive hybridization between the stocked population and both source populations. The proportion of fish returning to the river after a single winter at sea (versus several ones) was higher in fish assigned to the main source population than in local individuals. Moreover, during the first decade of the study, both single-sea-winter and multi-sea-winter (MSW) fish assigned to the main source population were smaller than local fish. During the second decade of the study, MSW fish defined as hybrids were lighter and smaller than fish from parental populations, suggesting outbreeding depression. Overall, this study suggests that supplementation with non-local individuals may alter not only the genetic diversity of wild populations but also life-history traits of adaptive significance.尽管利用非本土且可能已驯化的个体开展种群引种与增殖放流，可能对野生种群造成显著的进化影响，但目前鲜有研究记录增殖补充种群的遗传多样性与生活史性状的演化规律。本研究针对1989年至2009年间的大西洋鲑（Salmo salar）种群展开跟踪调查，该种群在研究初期的十年间，接受了两个遗传特征与表型特征均存在显著差异的外来源种群的增殖放流。我们分析了该种群在15个微卫星位点（microsatellite loci）上的遗传混合情况，以及表型性状随年度的变化趋势。研究结果显示，放流种群与两个外来源种群之间的渐渗杂交（introgressive hybridization）水平随时间推移逐渐升高。相较于本地种群个体，归属于主要源种群的鲑鱼中，仅在海中越冬一次便洄游至河流的个体占比更高（相较于多次越冬后洄游的个体）。此外，在研究的第一个十年间，归属于主要源种群的单越冬（single-sea-winter, SSW）个体与多越冬（multi-sea-winter, MSW）个体，其体型均小于本地种群个体。在研究的第二个十年间，被鉴定为杂交个体的多越冬（MSW）鲑鱼，其体重与体型均低于亲本种群个体，这表明存在远交衰退（outbreeding depression）现象。综上，本研究表明，引入非本土个体开展种群增殖补充，不仅可能改变野生种群的遗传多样性，还会影响具有适应意义的生活史性状。