Jiménez-Mena Belén, Le Moan Alan, Christensen Asbjørn, van Deurs Mikael, Mosegaard Henrik, Hemmer-Hansen Jakob, Bekkevold Dorte
Section for Marine Living Resources National Institute of Aquatic Resources Technical University of Denmark Silkeborg Denmark.
Evol Appl. 2019 Nov 1;13(2):376-387. doi: 10.1111/eva.12875. eCollection 2020 Feb.
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 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.
玉筋鱼是一类在生态上具有重要意义的鱼类；它们是食物链的关键部分，为海洋哺乳动物、海鸟和鱼类提供食物。玉筋鱼还受到大型工业渔业的捕捞，这引发了对生态系统影响的担忧。在北海，细纹玉筋鱼是渔业中目前最为常见的玉筋鱼种类。北海加卡特加特海峡的玉筋鱼管理目前基于种群统计学、种群动态以及幼体扩散模拟结果的细微差异，划分为七个地理区域。然而，对于其潜在的遗传种群结构却知之甚少。在本研究中，我们使用了通过限制性位点关联DNA测序（RADseq）获得的2522个单核苷酸多态性（SNP），对代表四个主要玉筋鱼管理区域的429条鱼进行了分型。我们的主要结果显示：（a）在大多数遗传标记中缺乏明确的空间定义的遗传结构；（b）存在一组至少13个处于强连锁不平衡状态的SNP，它们共同将北海玉筋鱼分为三个单倍型簇，这表明基因组中存在一个或多个结构变异。对这些假定结构变异的空间分布分析表明，沿着苏格兰海岸的西部管理区域的玉筋鱼至少存在部分生殖隔离，这支持了单独管理的必要性。我们的结果凸显了应用大量标记以检测微弱分化模式的重要性。本研究有助于增加对这种重要的被开发利用物种的遗传知识了解，其结果可用于增进我们对种群动态和种群结构的理解。
