1. Sharks are a priority for conservation because numerous species, including small‐sized coastal species, are being heavily exploited by commercial and recreational fisheries. Understanding the genetic population structure of sharks is key to effective management, maximizing their evolutionary potential in a rapidly changing environment and preventing population declines.
2. Limited dispersal is an important factor promoting population divergence for several coastal shark species. The genetic variation in 14 microsatellite loci and 21,006 single nucleotide polymorphisms genotyped using restriction‐site‐associated DNA sequencing was analysed to assess the genetic structure of the bonnethead shark, Sphyrna tiburo, in the western North Atlantic.
3. Genetic differences were identified among three well‐defined regions: the western Florida coast, the south‐eastern US Atlantic coast, and the southern Gulf of Mexico. Results support previous studies based on mitochondrial DNA sequences in defining differences among these regions and suggest limitations of bonnethead sharks in routinely performing long‐distance migrations.
4. The limited connectivity among regions explains the pattern of genetic divergence but also reported divergence at the species/subspecies level. These genetically discrete bonnethead populations have independent evolutionary histories that may include local adaptations to specific areas.
5. Bonnethead sharks are currently managed as two stocks in the USA owing to recent genetic, tagging, and life history studies; however, no stock assessments or management plans exist for Mexico. These results not only serve to reinforce US management strategies and provide critical data about the extent of gene flow and sex dispersal among populations, but also begin the process of effective management in the waters of Mexico to ensure the long‐term productivity and resilience of this species. With an absence of gene flow between populations from US waters and the southern Gulf of Mexico, there is a need for management plans based upon independent biological and population dynamics data since limited or no opportunities for populations to interchange individuals may occur to re‐establish population viability.

中文翻译：

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北大西洋西部鱼鲨的种群遗传多样性：对保护的意义

1. 鲨鱼是保护工作的重中之重，因为商业和休闲渔业正在大量开发包括小型沿海物种在内的许多物种。了解鲨鱼的遗传种群结构是有效管理，在迅速变化的环境中最大化其进化潜力并防止种群减少的关键。
2. 有限的扩散是促进几种沿海鲨鱼物种种群差异的重要因素。在14个微卫星标记和21006个的单核苷酸多态性的遗传变异使用限制位点相关的DNA测序分析，以评估所述窄头双髻鲨鲨鱼，遗传结构基因分型Sphyrna tiburo，在北大西洋西部。
3. 在三个明确定义的区域之间鉴定出遗传差异：佛罗里达州西部沿海，美国东南部东南沿海和墨西哥湾南部。结果支持先前基于线粒体DNA序列的研究，以定义这些区域之间的差异，并表明在常规进行长距离迁移时，net鱼鲨的局限性。
4. 区域之间有限的连通性解释了遗传差异的模式，但也报告了物种/亚种水平的差异。这些遗传上离散的net蜂种群具有独立的进化史，其中可能包括对特定区域的局部适应。
5. 由于最近的遗传，标签和生活史研究，头鲨目前在美国作为两种种群进行管理。但是，墨西哥没有存货评估或管理计划。这些结果不仅有助于加强美国的管理策略，并提供有关人群中基因流动和性别扩散程度的重要数据，而且还可以在墨西哥海域开始有效管理的过程，以确保该种群的长期生产力和复原力。种类。由于美国水域和墨西哥湾南部的种群之间没有基因流动，因此有必要基于独立的生物学和种群动态数据制定管理计划，因为可能不会出现种群互换的机会有限或没有机会重建种群可行性。