In the present study, the population genetic structure of the Pacific thread herring (Opisthonema libertate) was analyzed through mitochondrial DNA (mtDNA) control region sequences. Organisms were collected from June 2015 to July 2015 from four commercial landing sites (Bahia Magdalena, Guaymas and Mazatlan, Mexico, and Puntarenas, Costa Rica) and one artisanal sampling site (Puerto La Libertad, El Salvador). A total of 125 sequences were analyzed. High levels of haplotype (h = 0.990) and nucleotide (π = 0.030) diversity were found. Pairwise Φst comparisons indicated differences attributed mainly to the organisms from El Salvador. However, Bayesian inferences did not support the existence of different populations. The haplotype distribution between locations did not show a clear phylogeographic pattern. Mismatched distribution showed a unimodal pattern for the five sampled areas, indicative of sudden demographic expansion. These results were supported by Bayesian skyline plot. Our results do not support the hypothesis that the Pacific thread herring presents a population genetic structure. Future genetic comparisons should include a larger number of samples as well as more polymorphic molecular markers to further support our results.

在本研究中，通过线粒体DNA（mtDNA）控制区序列分析了太平洋线鲱（Opisthonema libertate）的种群遗传结构。从2015年6月至2015年7月，从四个商业着陆点（墨西哥的巴伊亚·马格达莱纳和墨西哥的马萨特兰，哥斯达黎加的蓬塔雷纳斯）和一个手工采样点（萨尔瓦多的波利托·拉·利伯塔德）收集了生物。总共分析了125个序列。高单倍型（h  = 0.990）和核苷酸（π= 0.030）的多样性。成对的Φst比较表明差异主要归因于萨尔瓦多的生物。但是，贝叶斯推论并不支持不同人群的存在。位置之间的单倍型分布没有显示明确的系统地理模式。分布不匹配显示五个采样区域的单峰模式，表明人口突然膨胀。这些结果得到了贝叶斯天际线图的支持。我们的结果不支持太平洋线鲱呈现种群遗传结构的假设。未来的遗传比较应包括更多的样本以及更多的多态性分子标记，以进一步支持我们的结果。