Trophic relationships and habitat preferences of delphinids from the southeastern Brazilian coast determined by carbon and nitrogen stable isotope composition

PLoS One. 2013 Dec 16;8(12):e82205. doi: 10.1371/journal.pone.0082205. eCollection 2013.

Abstract

To investigate the foraging habitats of delphinids in southeastern Brazil, we analyzed stable carbon (δ(13)C) and nitrogen (δ(15)N) isotopes in muscle samples of the following 10 delphinid species: Sotalia guianensis, Stenella frontalis, Tursiops truncatus, Steno bredanensis, Pseudorca crassidens, Delphinus sp., Lagenodelphis hosei, Stenella attenuata, Stenella longirostris and Grampus griseus. We also compared the δ(13)C and δ(15)N values among four populations of S. guianensis. Variation in carbon isotope results from coast to ocean indicated that there was a significant decrease in δ(13)C values from estuarine dolphins to oceanic species. S. guianensis from Guanabara Bay had the highest mean δ(13)C value, while oceanic species showed significantly lower δ(13)C values. The highest δ(15)N values were observed for P. crassidens and T. truncatus, suggesting that these species occupy the highest trophic position among the delphinids studied here. The oceanic species S. attenuata, G. griseus and L. hosei had the lowest δ(15)N values. Stable isotope analysis showed that the three populations of S. guianensis in coastal bays had different δ(13)C values, but similar δ(15)N results. Guiana dolphins from Sepetiba and Ilha Grande bays had different foraging habitat, with specimens from Ilha Grande showing more negative δ(13)C values. This study provides further information on the feeding ecology of delphinids occurring in southeastern Brazil, with evidence of distinctive foraging habitats and the occupation of different ecological niches by these species in the study area.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Brazil
  • Carbon Isotopes / analysis*
  • Dolphins / physiology*
  • Ecosystem*
  • Feeding Behavior / physiology*
  • Muscle, Skeletal / chemistry*
  • Nitrogen Isotopes / analysis*
  • Nutritional Status

Substances

  • Carbon Isotopes
  • Nitrogen Isotopes

Grants and funding

This study was supported by Rio de Janeiro State Government Research Agency – FAPERJ (“Pensa Rio” Program – Proc. E-26/110.371/2007 and APQ1-2009/1 - Proc. E26-110.858-2009), Ministry of Education of Brazil – CAPES (“Ciências do Mar” – Proc. 23038.051661/2009-18), Brazilian Research Council – CNPq (Proc. 482938/2007-2 and Proc. 480701/2009-1) and Cetacean Society International grant. This study was also supported by a scientific cooperation established between CNPq and F.R.S.-FNRS (Proc. 490471/2010-2 CNPq). TLB had a scholarship from the Ministry of Education of Brazil – CAPES, JL-B has a research grant from FAPERJ/UERJ (“Prociência” Program) and CNPq (grant #305303/2010-4), AFA has a research grant from CNPq (grant #304826/2008-1) and FAPERJ (JCNE #101.449/2010), OM has a research grant from CNPq and FAPERJ (CNE). GL and KD are F.R.S.-FNRS Research Associates. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.