Data from: Quantifying heritable variation in fitness-related traits of wild, farmed and hybrid Atlantic salmon families in a wild river environment

Farmed fish are typically genetically different from wild conspecifics. Escapees from fish farms may contribute one-way gene flow from farm to wild gene pools, which can depress population productivity, dilute local adaptations and disrupt coadapted gene complexes. Here, we reanalyse data from two experiments (McGinnity et al., 1997, 2003) where performance of Atlantic salmon (Salmo salar) progeny originating from experimental crosses between farm and wild parents (in three different cohorts) were measured in a natural stream under common garden conditions. Previous published analyses focussed on group-level differences but did not account for pedigree structure, as we do here using modern mixed-effect models. Offspring with one or two farm parents exhibited poorer survival in their first and second year of life compared with those with two wild parents and these group-level inferences were robust to excluding outlier families. Variation in performance among farm, hybrid and wild families was generally similar in magnitude. Farm offspring were generally larger at all life stages examined than wild offspring, but the differences were moderate (5–20%) and similar in magnitude in the wild versus hatchery environments. Quantitative genetic analyses conducted using a Bayesian framework revealed moderate heritability in juvenile fork length and mass and positive genetic correlations (>0.85) between these morphological traits. Our study confirms (using more rigorous statistical techniques) previous studies showing that offspring of wild fish invariably have higher fitness and contributes fresh insights into family-level variation in performance of farm, wild and hybrid Atlantic salmon families in the wild. It also adds to a small, but growing, number of studies that estimate key evolutionary parameters in wild salmonid populations. Such information is vital in modelling the impacts of introgression by escaped farm salmon.养殖鱼类通常与野生同类存在遗传差异。水产养殖场逃逸的个体可能会引发从养殖种群到野生种群的单向基因流动，此举会降低种群生产力、冲淡本地适应性，并破坏共适应基因复合体。本研究重新分析了两项实验（McGinnity等，1997、2003）的数据：该实验针对养殖与野生大西洋鲑（Salmo salar）亲本开展杂交，并在三个不同的同期群中，于自然溪流的共同花园实验条件下测量了其后代的生长表现。此前已发表的相关分析仅聚焦于组间差异，并未像本研究这般借助现代混合效应模型考量系谱结构。 携带一个或两个养殖亲本的后代，在生命的第一及第二个生长季的存活率均低于携带两个野生亲本的后代；且在剔除异常家系后，此类组水平的推断结果依然稳健。养殖、杂交与野生家系间的表现差异幅度总体相近。 各检测生活史阶段中，养殖后代的体型普遍大于野生后代，但差异幅度中等（5%~20%），且在野生环境与孵化场环境下的差异幅度相似。 采用贝叶斯框架开展的定量遗传分析显示，幼鱼的叉长与体重具有中等程度的遗传力，且这两个形态性状间存在较强的正遗传相关（>0.85）。 本研究借助更为严谨的统计技术，验证了此前"野生鱼类后代始终具有更高适合度"的研究结论，并为野生环境下养殖、野生与杂交大西洋鲑家系的表现差异提供了全新的家系水平解析视角。本研究还为为数不多但数量持续增长的、估算野生鲑科鱼类种群关键进化参数的研究成果增添了新的证据。此类信息对于模拟逃逸养殖鲑的基因渐渗所带来的生态影响至关重要。