Dear MARMAM Readers,

My co-authors and I are pleased to announce the publication of our recent article in Marine Biology:

Troina, G.C., Botta, S., Dehairs, F., Di Tullio, J., Elskens, M., Secchi, E.R. Skin δ¹³C and δ¹⁵N reveal spatial and temporal patterns of habitat and resource use by free-ranging odontocetes from the southwestern Atlantic Ocean. Mar Biol 167, 186 (2020). https://doi.org/10.1007/s00227-020-03805-8

ABSTRACT: Large diversity and abundance of cetacean species occur along the Brazilian outer continental shelf and slope waters. In the present study we analysed carbon (δ¹³C) and nitrogen (δ¹⁵N) stable isotopes in skin biopsies of ten odontocete species (Delphinidae and Physeteridae) to assess the intra- and interspecific 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 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. 

 

The article can be accessed via the link https://rdcu.be/cbadj

Do not hesitate to contact me (genyffertroina@gmail.com) if you have any comments or questions.  

Kind regards,

Genyffer Troina