Large diversity and abundance of cetacean species occur along the Brazilian outer continental shelf and slope waters. In the present study, we analyzed carbon (δ13C) and nitrogen (δ15N) stable isotopes in skin biopsies of ten odontocete species (Delphinidae and Physeteridae) to assess the intra- and inter-specific patterns in the use of resources along the region. Our isotopic analysis allowed us to identify two potential subpopulations of Stenella frontalis. High core isotopic niche overlap between S. frontalis from the southern range of the study area and Delphinus delphis, especially in spring, suggested that they share similar resources and rely on spatiotemporal segregation to achieve niche differentiation and to minimize competition. Our isotopic data also pointed to high similarity among Tursiops truncatus, S. frontalis, and Globicephala melas in the use of resources. Steno bredanensis had the highest δ15N and δ13C, which agrees with its occurrence in neritic waters. S. longirostris showed consistently low δ15N values, indicating that they feed at relatively lower trophic levels, and lack of niche overlap with most delphinid species, except S. attenuata. Orcinus orca and G. melas had very similar δ13C and δ15N values, that were consistent with feeding in offshore waters. δ13C and δ15N in Physeter macrocephalus suggested that individuals feed on similar trophic levels, but over a wide spatial range. The analyses of stable isotopes in skin biopsies helped us to refine our knowledge about the intra-specific resource and habitat use, ecological niches, and the trophic interactions amongst co-occurring cetaceans from the oceanic waters of the subtropical western South Atlantic.

中文翻译：

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皮肤 δ13C 和 δ15N 揭示了大西洋西南部自由放养的齿鲸栖息地和资源利用的时空模式

沿巴西外大陆架和斜坡水域分布着大量的鲸类物种。在本研究中，我们分析了 10 种齿科动物（海豚科和鸬鹚科）皮肤活检中的碳 (δ13C) 和氮 (δ15N) 稳定同位素，以评估该地区资源利用的种内和种间模式。我们的同位素分析使我们能够确定 Stenella frontalis 的两个潜在亚群。来自研究区南部范围的 S. frontalis 和 Delphinus delphis 之间的高核心同位素生态位重叠，特别是在春季，表明它们共享相似的资源并依靠时空隔离来实现生态位分化并最大限度地减少竞争。我们的同位素数据还表明 Tursiops truncatus、S. frontalis、和 Globicephala melas 在资源的利用上。Steno bredanensis δ15N 和 δ13C 最高，这与它在浅海水域中的出现一致。S. longirostris 显示出始终较低的 δ15N 值，表明它们以相对较低的营养水平为食，并且与除 S. attenuata 之外的大多数海豚科物种缺乏生态位重叠。Orcinus orca 和 G. melas 具有非常相似的 δ13C 和 δ15N 值，这与在近海水域觅食一致。Physeter macrocephalus 中的 δ13C 和 δ15N 表明个体以相似的营养水平为食，但空间范围很广。皮肤活检中稳定同位素的分析帮助我们完善了对特定资源和栖息地利用、生态位、