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 dolphins vs the 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.

We investigated the habitat use and feeding ecology of 10 cetacean species encountered along the south-eastern coast of Brazil (24–26°S) using carbon (δ13C) and nitrogen (δ15N) stable isotopes. Hierarchical cluster analysis distinguished two main groups based on their isotopic patterns. One group included migratory baleen whales (Megaptera novaeangliae and Eubalaena australis) with the lowest δ13C and δ15N values, reflecting baseline isotopic values of their Subantarctic feeding grounds and consumption of lower trophic level prey. Resident species and those occasionally occurring in Brazilian coastal waters highly differed from the migratory whales in their isotopic values. In this group, Tursiops truncatus had the highest δ13C and δ15N values, indicating coastal habits and relatively higher trophic position. Similar δ13C values were observed in Sotalia guianensis, Pontoporia blainvillei, Orcinus orca and Steno bredanensis. However, the former two species had lower δ15N values than the latter two, indicating different trophic positions. The relatively lower δ13C values observed in Stenella frontalis suggest greater influence of pelagic prey in their diet. Furthermore, the lower δ13C values observed in Delphinus delphis and Balaenoptera edeni were associated with upwelling events that occur along the region, affecting the isotopic values of their main prey. Juvenile M. novaeangliae had higher δ13C and δ15N than the adults, which may indicate feeding in areas with different isoscapes and consumption of pelagic schooling fish with relatively higher trophic levels than krill. This study provides preliminary information that are useful to understand the habitat use and coexistence of cetacean species occurring in south-eastern Brazil.

Trophic ecology and foraging areas of cetaceans sampled in the coastal waters of south-eastern Brazil assessed through skin δ13C and δ15N -CORRIGENDUM.

Agradeço ao Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) pela bolsa concedida durante os dois anos de mestrado, a qual foi essencial para o desenvolvimento deste projeto. À empresa "Alucia Productions", atualmente "Ocean X", e ao Woods Hole Oceanographic Institution (WHOI), por ter proporcionado a oportunidade de realização de dois cruzeiros oceanográficos em 2017 em Fernando de Noronha, e que envolveram a coleta de material biológico para este estudo. Ao meu orientador, Prof. Dr. Marcos César de Oliveira Santos, por todos os ensinamentos científicos, pela paciência, conselhos, brincadeiras e por me proporcionar desde o início da minha graduação, e agora pós, a oportunidade de me conectar com as maravilhas envolvendo os mamíferos aquáticos e o oceano de modo geral. Gostaria de agradecer também aos membros da minha banca, os Professores Teodóro Vaske Júnior e Silvina Botta, pelas fantásticas contribuições que me proporcionaram muito aprendizado para a finalização desta importante etapa da minha vida. Ao Prof. Dr. Raymond Lee, coordenador do Stable Isotope Core Laboratory da Universidade do Estado de Washington (WSU), pelo auxílio nas análises isotópicas das amostras utilizadas no presente trabalho. A