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.

养殖鱼类通常在遗传上与野生同种个体存在差异。养殖场逃逸的鱼类可能导致从养殖群体到野生基因库的单向基因流，这会降低种群生产力、稀释本地适应性并破坏协同适应的基因复合体。本研究重新分析了两项实验（McGinnity等，1997，2003）的数据，这些实验在自然溪流的共同园条件（common garden conditions）下，测定了来自养殖与野生亲本实验杂交的大西洋鲑（Salmo salar）后代（三个不同群体）的表现。先前发表的分析聚焦于群体水平的差异，但未考虑谱系结构（pedigree structure），而本研究使用现代混合效应模型（mixed-effect models）对此进行了校正。与双亲均为野生的后代相比，具有一个或两个养殖亲本的后代在其生命的第一年和第二年存活率更低，且排除异常值家系后，这些群体水平的推断依然稳健。养殖、杂交和野生家系之间的表现变异程度总体相似。在所有检测的生命阶段，养殖后代总体上比野生后代体型更大，但差异程度中等（5-20%），且在野生与孵化场环境中差异幅度相似。利用贝叶斯框架（Bayesian framework）进行的数量遗传学分析（quantitative genetic analyses）显示，幼鱼叉长和体重具有中等遗传力（heritability），且这些形态性状之间存在强正遗传相关（>0.85）。本研究（通过更严谨的统计技术）证实了先前研究的结论——野生鱼类后代始终具有更高的适合度（fitness），并为养殖、野生及杂交大西洋鲑家系在自然环境中的家系水平表现变异提供了新见解。此外，本研究还补充了数量虽少但不断增长的、估算野生鲑科鱼类种群关键进化参数的研究。此类信息对于模拟养殖逃逸鱼类基因渗入（introgression）的影响至关重要。