Bottlenose dolphins (Tursiops truncatus) have been surveyed for at least two decades on the southern Brazilian coast. However, little is known about their distribution and habitat use in lower latitudes of the South-western Atlantic Ocean. Aiming to study the movements and distribution of the species along the south-eastern Brazilian coast, we made a comparison of photo-identified individuals of the species catalogued in 21 cruises conducted between 2012 and 2015. Additionally, we performed stable isotope analyses of carbon and nitrogen in skin samples (N = 35) to provide some insights of dolphin habitat use and trophic ecology through comparisons among individuals of distinct surveyed sectors (northern and southern) and sex. A total of 177 individuals were identified. Re-sightings (N = 24) occurred at intervals from 82 to 979 days at distances from 7 to 179 km. No individual was sighted in both sectors, suggesting spatial segregation. Isotopic comparisons showed no significant differences in carbon and nitrogen signatures between distinct sectors. However, ecological divergences were found when we divided the samples by gender. Wider isotopic niches were found for the northern bottlenose dolphinsvsthe southern ones, which could be related to temporal and spatial variation in the availability of resources, as well as possible differences in the home ranges of males and females in each region. This study represents a preliminary evaluation of ecological aspects of bottlenose dolphins along the Brazilian south-eastern coast, however, long-term studies on the feeding ecology and habitat use of this species are important to further improve our knowledge.

中文翻译：

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巴西东南部宽吻海豚 (Tursiops truncatus) 的活动和栖息地利用

宽吻海豚 (截尾草) 在巴西南部海岸进行了至少 20 年的调查。然而，人们对它们在西南大西洋低纬度地区的分布和栖息地利用知之甚少。为了研究该物种沿巴西东南部海岸的运动和分布，我们对 2012 年至 2015 年间进行的 21 次航行中记录的物种的照片识别个体进行了比较。此外，我们对碳和皮肤样本中的氮（N = 35），通过不同调查部门（北部和南部）和性别的个体之间的比较，提供有关海豚栖息地使用和营养生态学的一些见解。共确定了 177 人。在 7 至 179 公里的距离处，以 82 至 979 天的间隔发生重新目击（N = 24）。在这两个部门都没有看到任何个体，这表明存在空间隔离。同位素比较显示不同部门之间的碳和氮特征没有显着差异。然而，当我们按性别划分样本时，发现了生态差异。北方宽吻海豚发现了更广泛的同位素生态位对比南方的，这可能与资源可用性的时间和空间差异有关，以及每个地区男性和女性的家庭范围可能存在差异。这项研究代表了对巴西东南沿海宽吻海豚生态方面的初步评估，然而，对该物种的摄食生态和栖息地利用的长期研究对于进一步提高我们的知识很重要。