Barragán-Barrera Dalia C, May-Collado Laura J, Tezanos-Pinto Gabriela, Islas-Villanueva Valentina, Correa-Cárdenas Camilo A, Caballero Susana
Laboratorio de Ecología Molecular de Vertebrados Acuáticos LEMVA, Departamento de Ciencias Biológicas, Universidad de los Andes, Laboratorio J-202, Bogotá, Colombia.
Fundación Macuáticos Colombia, Medellín, Colombia.
PLoS One. 2017 Dec 13;12(12):e0189370. doi: 10.1371/journal.pone.0189370. eCollection 2017.
The current conservation status of the bottlenose dolphin (Tursiops truncatus) under the IUCN is 'least concern'. However, in the Caribbean, small and localized populations of the 'inshore form' may be at higher risk of extinction than the 'worldwide distributed form' due to a combination of factors including small population size, high site fidelity, genetic isolation, and range overlap with human activities. Here, we study the population genetic structure of bottlenose dolphins from the Archipelago of Bocas del Toro in Panama. This is a small population characterized by high site fidelity and is currently heavily-impacted by the local dolphin-watching industry. We collected skin tissue samples from 25 dolphins to study the genetic diversity and structure of this population. We amplified a portion of the mitochondrial Control Region (mtDNA-CR) and nine microsatellite loci. The mtDNA-CR analyses revealed that dolphins in Bocas del Toro belong to the 'inshore form', grouped with the Bahamas-Colombia-Cuba-Mexico population unit. They also possess a unique haplotype new for the Caribbean. The microsatellite data indicated that the Bocas del Toro dolphin population is highly structured, likely due to restricted movement patterns. Previous abundance estimates obtained with mark-recapture methods reported a small population of 80 dolphins (95% CI = 72-87), which is similar to the contemporary effective population size estimated in this study (Ne = 73 individuals; CI = 18.0 - ∞; 0.05). The combination of small population size, high degree of genetic isolation, and intense daily interactions with dolphin-watching boats puts the Bocas del Toro dolphin to at high risk of extinction. Despite national guidelines to regulate the dolphin-watching industry in Bocas del Toro and ongoing educational programs for tour operators, only in 2012 seven animals have died due to boat collisions. Our results suggest that the conservation status of bottlenose dolphins in Bocas del Toro should be elevated to 'endangered' at the national level, as a precautionary measure while population and viability estimates are conducted.
根据国际自然保护联盟（IUCN）的标准，宽吻海豚（Tursiops truncatus）目前的保护状况为“无危”。然而，在加勒比地区，由于种群规模小、地点忠诚度高、基因隔离以及与人类活动范围重叠等多种因素的综合作用，“近岸型”的小型局部种群可能比“全球分布型”面临更高的灭绝风险。在此，我们研究了巴拿马博卡斯德尔托罗群岛宽吻海豚的种群遗传结构。这是一个以高地点忠诚度为特征的小种群，目前受到当地观豚业的严重影响。我们从25只海豚身上采集了皮肤组织样本，以研究该种群的遗传多样性和结构。我们扩增了线粒体控制区（mtDNA-CR）的一部分以及九个微卫星位点。mtDNA-CR分析表明，博卡斯德尔托罗的海豚属于“近岸型”，与巴哈马-哥伦比亚-古巴-墨西哥种群单元归为一组。它们还拥有一种加勒比地区新发现的独特单倍型。微卫星数据表明，博卡斯德尔托罗海豚种群结构高度分化，可能是由于活动模式受限所致。先前通过标记重捕法获得的丰度估计报告称，该种群数量少，仅有80只海豚（95%置信区间 = 72 - 87），这与本研究中估计的当代有效种群大小相似（Ne = 73只个体；置信区间 = 18.0 - ∞；0.05）。种群规模小、高度的基因隔离以及与观豚船的日常密集互动，使得博卡斯德尔托罗的海豚面临极高的灭绝风险。尽管博卡斯德尔托罗有国家规范观豚业的指导方针，并且针对旅游经营者开展了持续的教育项目，但仅在2012年就有7只海豚死于船只碰撞。我们的结果表明，作为一项预防措施，在进行种群和生存力估计的同时，博卡斯德尔托罗宽吻海豚在国家层面的保护状况应提升至“濒危”。
