Data from: Genetic monitoring reveals temporal stability over 30 years in a small, lake resident brown trout population

Knowledge of the degree of temporal stability of population genetic structure and composition is important for understanding microevolutionary processes and for addressing issues on human impact on natural populations. We know little about how representative single samples in time are to reflect population genetic constitution. We explore the temporal genetic variability patterns over a 30-year period of annual sampling of a lake resident brown trout (Salmo trutta) population, covering 37 consecutive cohorts and five generations. Levels of variation remain largely stable over this period with no indication of substructuring within the lake. We detect genetic drift, however, and the genetically effective population size (Ne) was assessed from allele frequency shifts between consecutive cohorts using an unbiased estimator that accounts for the effect of overlapping generation. The overall mean Ne is estimated as 74. We find indications that Ne varies over time, but th ere is no obvious temporal trend. We also estimated Ne using a one-sample approach based on linkage disequilibrium (LD) not accounting for the effect of overlapping generations. Combining one-sample estimates for all years gives an Ne estimate of 76. This similarity between estimates may be coincidental or reflecting a general robustness of the LD approach to violations of the discrete generations assumption. In contrast to the observed genetic stability, body size and catch per effort have increased over the study period. Estimates of annual effective number of breeders (Nb) correlated with catch per effort suggesting that genetic monitoring can be used for detecting fluctuations in abundance.

明晰种群遗传结构（population genetic structure）与组成的时间稳定性程度，对于理解微进化过程、解析人类活动对自然种群的影响具有重要意义。目前学界对单次时间采样能否反映种群遗传组成的代表性仍知之甚少。本研究针对一个定居湖泊的褐鳟（Salmo trutta）种群开展了长达30年的年度采样，覆盖连续37个同龄群与5个世代，以此探究其时间遗传变异模式。

研究期间，种群遗传变异水平整体保持稳定，未在该湖泊内发现种群亚结构的迹象。但我们检测到了遗传漂变现象：通过可校正重叠世代效应的无偏估计量，基于连续同龄群间的等位基因频率偏移估算了遗传有效种群大小（Ne），其总体均值为74。结果显示Ne随时间存在波动，但未呈现显著的时间趋势。

我们同时采用基于连锁不平衡（LD）的单样本方法估算Ne，该方法未考虑重叠世代的影响。合并所有年度的单样本估算结果，得到的Ne估值为76。两种估算结果的一致性或属偶然，也可能反映出连锁不平衡方法对违背离散世代假设的场景具备一定稳健性。

与观测到的遗传稳定性形成鲜明对比的是，本研究期间种群的体型与单位捕捞努力量渔获量均呈上升趋势。年度繁殖有效种群数量（Nb）的估算值与单位捕捞努力量渔获量呈显著相关，这表明遗传监测可用于探测种群丰度的波动。