Data from: Habitat-driven population structure of bottlenose dolphins, Tursiops truncatus, in the North-East Atlantic

Despite no obvious barrier to gene flow, historical environmental processes and ecological specializations can lead to genetic differentiation in highly mobile animals. Ecotypes emerged in several large mammal species as a result of niche specializations and/or social organization. In the North-West Atlantic, two distinct bottlenose dolphin (Tursiops truncatus) ecotypes (i.e. ‘coastal’ and ‘pelagic’) have been identified. Here, we investigated the genetic population structure of North-East Atlantic (NEA) bottlenose dolphins on a large scale through the analysis of 381 biopsy-sampled or stranded animals using 25 microsatellites and a 682-bp portion of the mitochondrial control region. We shed light on the likely origin of stranded animals using a carcass drift prediction model. We showed, for the first time, that coastal and pelagic bottlenose dolphins were highly differentiated in the NEA. Finer-scale population structure was found within the two groups. We suggest that distinct founding events followed by parallel adaptation may have occurred independently from a large Atlantic pelagic population in the two sides of the basin. Divergence could be maintained by philopatry possibly as a result of foraging specializations and social organization. As coastal environments are under increasing anthropogenic pressures, small and isolated populations might be at risk and require appropriate conservation policies to preserve their habitats. While genetics can be a powerful first step to delineate ecotypes in protected and difficult to access taxa, ecotype distinction should be further documented through diet studies and the examination of cranial skull features associated with feeding.

尽管基因交流不存在明显障碍，但历史环境进程与生态特化仍可导致高度移动性动物出现遗传分化。若干大型哺乳动物类群的生态型（ecotype）即因生态位特化或社会组织而形成。在西北大西洋，研究者已发现两种截然不同的宽吻海豚（Tursiops truncatus）生态型，即“近岸型”与“远洋型”。本研究通过对381份活检采样或搁浅个体的25个微卫星（microsatellite）位点以及线粒体控制区（mitochondrial control region）682 bp片段进行分析，对东北大西洋（North-East Atlantic, NEA）宽吻海豚的种群遗传结构开展了大规模探究。本研究还利用尸体漂移预测模型，揭示了搁浅个体的潜在来源。本研究首次证实，东北大西洋海域的近岸型与远洋型宽吻海豚存在显著遗传分化。两类生态型内部还存在更精细的种群结构。研究推测，大西洋远洋大型种群可能分别在该海域盆地两侧经历了独立的奠基事件，随后发生了趋同适应。这种遗传分化可能因出生地眷恋（philopatry）得以维持，而出生地眷恋或许由觅食特化与社会组织所催生。由于近岸环境正面临日益加剧的人为活动压力，小型且孤立的种群可能面临生存风险，亟需制定合理的保护政策以保护其栖息生境。尽管遗传学可作为界定受保护且难以观测类群生态型的高效首要手段，但生态型的区分还需通过食性研究以及与摄食相关的颅骨形态特征分析来进一步佐证。