Data from: Oceanographic connectivity and environmental correlates of genetic structuring in Atlantic herring in the Baltic Sea

Marine fish often show little genetic structuring in neutral marker genes, and Atlantic herring (Clupea harengus) in the Baltic Sea are no exception; historically, very low levels of population differentiation (FST ≈ 0.002) have been found, despite a high degree of interpopulation environmental heterogeneity in salinity and temperature. Recent exome sequencing and SNP studies have however shown that many loci are under selection in this system. Here, we combined population genetic analyses of a large number of transcriptome-derived microsatellite markers with oceanographic modelling to investigate genetic differentiation and connectivity in Atlantic herring at a relatively fine scale within the Baltic Sea. We found evidence for weak but robust and significant genetic structuring (FST = 0.008) explainable by oceanographic connectivity. Genetic differentiation was also associated with site differences in temperature and salinity, with the result driven by the locus Her14 which appears to be under directional selection (FST = 0.08). The results show that Baltic herring are genetically structured within the Baltic Sea, and highlight the role of oceanography and environmental factors in explaining this structuring. The results also have implications for the management of herring fisheries, the most economically important fishery in the Baltic Sea, suggesting that the current fisheries management units may be in need of revision.

海洋鱼类的中性标记基因通常几乎不存在遗传结构分化，波罗的海大西洋鲱（Clupea harengus）亦不例外；既往研究虽观测到种群间盐度与温度存在高度环境异质性，但群体分化水平极低（FST≈0.002，即固定化指数Fixation Index）。然而近期的外显子组测序（exome sequencing）与单核苷酸多态性（Single Nucleotide Polymorphism, SNP）研究表明，该体系下诸多基因座处于选择压力之下。本研究结合大量转录组衍生微卫星标记的群体遗传学分析与海洋学模拟，在波罗的海海域内以相对精细的尺度探究大西洋鲱的遗传分化与连通性。结果显示存在微弱但稳健且显著的遗传结构分化（FST=0.008），该分化可通过海洋连通性得到解释。遗传分化还与各采样点的温度、盐度差异相关，这一结果主要由处于定向选择压力下的基因座Her14所驱动（FST=0.08）。本研究结果证实波罗的海大西洋鲱在海域内存在遗传结构分化，并凸显了海洋学过程与环境因子对该结构形成的关键作用。此外，该结果对波罗的海规模最大、经济价值最高的鲱鱼渔业管理具有重要参考意义，表明当前的渔业管理单元或需进行修订。