Dynamic marine environments can shape complex spatial and temporal patterns in the population connectivity of marine species, and this is often exemplified in species with long larval phases. Here, we used a genotyping-by-sequencing (GBS) approach to examine fine-scale spatial and temporal genomic variation among Dungeness crab Cancer magister larval recruits sampled in the California Current Ecosystem. Specifically, we compared samples collected during expectedand late-season recruitment time periods within 2 consecutive years (2017 and 2018) at 2 sites in Oregon, USA (Yaquina Bay and Coos Bay). Evidence was found for high gene flow between the expectedand late-season recruits within each year and at both sites based on 1389 neutral loci. In contrast, strong genetic differentiation was observed between these 2 groups within each year and at both sites based on variation at 2 putatively adaptive loci. Contrary to prediction, the magnitude of genetic differentiation between these 2 seasonal groups was greater in 2017 when the Pacific Decadal Oscillation was stronger, upwelling was weaker, and the spring transition was later. Spatial genetic variation was not observed within 2017 or 2018. Comparing across years, expectedand late-season groups were differentiated at putatively adaptive loci. Interestingly, strong genetic differentiation was also observed between late-season groups across years. We found no evidence for cohesive larval dispersal among recruits based on genetic related ness estimates. Overall, our findings provide evidence for high connectivity within Dungeness crab, but suggest that selective pressures and ocean conditions influence the genetic composition of larval recruits both intraand inter-annually.

中文翻译：

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加州当前生态系统中邓杰内斯蟹（巨蟹座）幼虫新兵的精细时空基因组变异

动态海洋环境可以塑造海洋物种种群连通性的复杂时空模式，这通常在具有较长幼虫阶段的物种中得到体现。在这里，我们使用基因分型测序 (GBS) 方法来检查在加利福尼亚当前生态系统中采样的邓杰内斯蟹癌症 magister 幼虫新兵之间的精细时空基因组变异。具体来说，我们比较了连续两年（2017 年和 2018 年）在美国俄勒冈州的两个地点（亚奎纳湾和库斯湾）的预期和晚季招募时间段收集的样本。根据 1389 个中性位点，在每年和两个地点的预期和晚季新兵之间发现了高基因流动的证据。相比之下，基于 2 个假定的适应性位点的变异，每年在这两个群体之间以及在两个地点都观察到强烈的遗传分化。与预测相反，2017年太平洋年代际振荡较强，上升流较弱，春季过渡较晚，这两个季节组之间的遗传分化程度更大。2017 年或 2018 年未观察到空间遗传变异。跨年比较，预期和晚季组在推定的适应性位点上有所区分。有趣的是，在不同年份的晚季组之间也观察到了强烈的遗传分化。根据遗传相关性估计，我们没有发现新兵之间有凝聚力的幼虫扩散的证据。总体而言，我们的发现提供了邓杰内斯蟹内部高度连通性的证据，