Sandeels are an ecologically important group of fishes; they are a key part of the food chain serving as food for marine mammals, seabirds and fish. Sandeels are further targeted by a large industrial fishery, which has led to concern about ecosystem effects. In the North Sea, the lesser sandeel Ammodytes marinus is by far the most prevalent species of sandeel in the fishery. Management of sandeel in the North Sea plus the Kattegat is currently divided into seven geographical areas, based on subtle differences in demography, population dynamics and results from simulations of larval dispersal. However, little is known about the underlying genetic population structure. In this study, we used 2,522 SNPs derived from restriction site‐associated DNA sequencing (RADseq) typed in 429 fish representing four main sandeel management areas. Our main results showed (a) a lack of a clear spatially defined genetic structure across the majority of genetic markers and (b) the existence of a group of at least 13 SNPs under strong linkage disequilibrium which together separate North Sea sandeel into three haplotype clusters, suggestive of one or more structural variants in the genome. Analyses of the spatial distribution of these putative structural variants suggest at least partial reproductive isolation of sandeel in the western management area along the Scottish coast, supporting a separate management. Our results highlight the importance of the application of a large number of markers to be able to detect weak patterns of differentiation. This study contributes to increasing the genetic knowledge of this important exploited species, and results can be used to improve our understanding of population dynamics and stock structure.

中文翻译：

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尽管在北海较小的沙e中，尽管有很强的基因组信号，但遗传结构仍然很弱。

沙e鱼是具有重要生态意义的鱼类。它们是食物链的重要组成部分，是海洋哺乳动物，海鸟和鱼类的食物。大型工业渔业进一步将桑德尔作为目标，这引起了人们对生态系统影响的关注。在北海，较小的三趾A Ammodytes marinus是迄今为止渔业中最普遍的桑德尔鱼种。基于人口，人口动态和幼虫扩散模拟结果的细微差异，北海和Kattegat地区的沙sand管理目前分为七个地理区域。但是，关于潜在的遗传种群结构知之甚少。在这项研究中，我们使用了来自于429个鱼类的限制性位点相关DNA测序（RADseq）的2,522个SNP，这些鱼类代表了四个主要的桑德尔管理区域。我们的主要结果表明（a）大多数遗传标记均缺乏明确的空间定义遗传结构，并且（b）在强连锁不平衡下存在一组至少13个SNP，它们将北海sandelel分为三个单倍型簇，提示基因组中的一种或多种结构变异。这些假定的结构变体的空间分布分析表明，在苏格兰沿海的西部管理地区，至少部分地隔离了桑德尔的繁殖，从而支持了单独的管理。我们的结果突出了应用大量标记物以检测弱分化模式的重要性。这项研究有助于增加这一重要开发物种的遗传知识，其结果可用于增进我们对种群动态和种群结构的了解。我们的结果突出了应用大量标记物以检测弱分化模式的重要性。这项研究有助于增加这一重要开发物种的遗传知识，其结果可用于增进我们对种群动态和种群结构的了解。我们的结果突出了应用大量标记物以检测弱分化模式的重要性。这项研究有助于增加这一重要开发物种的遗传知识，其结果可用于增进我们对种群动态和种群结构的了解。