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Marine Biology

, 166:76 | Cite as

Origin and foraging ecology of male loggerhead sea turtles from southern Brazil revealed by genetic and stable isotope analysis

  • Luciana MedeirosEmail author
  • Danielle S. Monteiro
  • Silvina Botta
  • Maíra C. Proietti
  • Eduardo R. Secchi
Original paper

Abstract

The southwestern Atlantic Ocean (SWA) represents an important foraging ground for loggerhead sea turtles (Caretta caretta). Most studies at the region have focused on adult females and juveniles, and little is known about males. Here, we present the first insights about origin and foraging ecology of male loggerheads from the SWA, by integrating genetic and stable isotope analysis (SIA). Skin samples were obtained from 26 males stranded along the southern coast of Brazil (from 31°21′S–51°05′W to 33°44′S–53°22′W), from February 2014 to March 2017. Samples of potential food sources (benthic and pelagic organisms) were also collected for SIA. A fragment of the mitochondrial DNA control region was sequenced and a Bayesian Mixed Stock Analysis was performed to estimate natal origins of male loggerheads. Bayesian Stable Isotope Mixing Models were fitted to assess the relative contribution of different food sources assimilated by males. Most males exhibit endemic haplotypes from Brazilian rookeries, followed by a low frequency of a haplotype from the North Atlantic and the Mediterranean Sea, as well as olive ridley (Lepidochelys olivaea) haplotype, showing hybridization. SIA showed life stage-related differences in feeding and habitat use by male loggerheads, with benthic invertebrates dominating the diet of adults, while pelagic prey items dominated the diet of juveniles. Our findings demonstrate the importance of southern Brazil neritic and oceanic habitats for male loggerheads and highlight the value of this area for the maintenance of SWA reproductive management units, which are the main contributors to these feeding aggregations.

Notes

Acknowledgements

We thank Núcleo de Educação e Monitoramento Ambiental—NEMA for support in tissue samplings. All samples were collected as part of beach and fisheries monitoring programs carried out by Laboratório de Ecologia e Conservação da Megafauna Marinha, Universidade Federal do Rio Grande—EcoMega/FURG—or by NEMA. We also thank Dr. Manuel Haimovici and Dr. Leonir André Colling for identification of invertebrates, Dr. Leandro Bugoni and Dr. Luis Gustavo Cardoso and two anonymous reviewers for the revision and comments that improved this manuscript. We also thank Tiago B. R. Gandra for map design. This article is part of L.M.’s Ph.D. thesis in Biological Oceanography (FURG, Brazil) under the supervision of E.R.S. and M.C.P and was authorized under SISBIO Licenses Nos. 15962-5 and 49019-1 to 49019-3. Financial support was provided by The Rufford Foundation, Coordenação de Aperfeiçoamento de Pessoal de Nível Superior- CAPES (Ministry of Education), Conselho Nacional de Desenvolvimento Científico e Tecnológico- CNPq (Brazilian Science, Technology and Innovation Ministry), Petrobras, Superintendência do Porto do Rio Grande and Yaqu Pacha. This work is a contribution of the research group Ecologia e Conservação da Megafauna Marinha—EcoMega/CNPq.

Funding

This study was financed in part by the Coordenação de Aperfeiçoamento de Pessoal de Nível SuperiorBrasil (CAPES)—Finance Code 001. CAPES provided a scholarship to L.M., as well as access to the Portal de Periódicos and financial support through Programa de Excelênca AcadêmicaPROEX. Financial support for sample collection during beach monitoring was provided by Petrobras, Superintendência do Porto do Rio Grande and Yaqu Pacha. The Rufford Foundation provided funding for laboratory work and analyses through the Rufford Small Grants program (Project nº 18836-1). Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) provided a Research Fellowship to E.R.S. (PQ 310597/2018-8) and M.C.P. (PQ 312470/2018-5).

Compliance with ethical standards

Conflict of interest

The authors declare that they have no conflict of interest.

Ethical approval

This article does not contain any studies with human participants. All applicable international, national, and institutional guidelines for the care and use of animals were followed. Sampling was conducted under SIBIO licenses Nos. 15962-5 and 49019-1 to 49019-3 (SISBIO- Sistema de Autorização e Informação em Biodiversidade). No live animals were used for experiments or sampling. All procedures performed in studies involving animals were in accordance with the ethical standards of the institution or practice at which the studies were conducted.

Supplementary material

227_2019_3524_MOESM1_ESM.pdf (318 kb)
Supplementary material 1 (PDF 318 kb)

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Authors and Affiliations

  1. 1.Programa de Pós-Graduação em Oceanografia BiológicaUniversidade Federal do Rio Grande-FURGRio GrandeBrazil
  2. 2.Laboratório de Ecologia e Conservação da Megafauna Marinha-EcoMegaUniversidade Federal do Rio Grande-FURGRio GrandeBrazil
  3. 3.Laboratório de Ecologia Molecular Marinha-LEMMUniversidade Federal de Rio Grande-FURGRio GrandeBrazil
  4. 4.Núcleo de Educação e Monitoramento Ambiental-NEMARio GrandeBrazil

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