[MARMAM] New publication: The isotopic niche of a tropical cetacean community

Mariana C Neves maricneves at gmail.com
Fri Jul 28 18:23:24 PDT 2023

Deal all,

My co-authors and I are pleased to share our new contribution:

 M.C. Neves, M. Vannuci-Silva, G. Montanini, A.F. Azevedo, J.
Lailson-Brito, T.L. Bisi (2023). From narrow and overlapped to wide and
segregated: The isotopic niche of a tropical cetacean community. Ecological

Species in sympatry can coexist due to some degree of niche partitioning.
Four cetacean species, Guiana (Sotalia guianensis), franciscana (Pontoporia
blainvillei), Atlantic spotted (Stenella frontalis), and rough-toothed
dolphins (Steno bredanensis), frequently occur in Ilha Grande Bay (RJ),
with three of them presenting residence pattern. This tropical bay is
considered a biodiversity hotspot and preserved by marine protected areas,
though located in a highly developed region of the Southwestern Atlantic
Ocean. To verify niche partitioning and segregation in these species and to
explore the trophic structure of this cetacean community, their isotopic
niches were investigated through carbon (δ13C) and nitrogen (δ15N) stable
isotopes in the muscle of specimens stranded in the region between 2012 and
2022. The rough-toothed dolphin had the largest niche area and high
segregation. On the other hand, there was a high niche overlap between the
species that have site fidelity patterns in the bay. The Atlantic spotted
dolphin had the highest values for almost all the Layman metrics, a large
niche area, and trophic diversity; the Guiana dolphin explored a diverse
variety of resources, and the franciscana dolphin presented the narrowest
and most overlapped niche and the lowest niche diversification. This is the
first study to access the trophic ecology of this cetacean community. Our
results indicate that the region is an important foraging area for three of
the studied species, with a high diversity and availability of resources
that might enable the high niche overlap observed for resident species. The
findings for the threatened and small franciscana population in this
recently discovered habitat bring concern. Therefore, the area deserves
conservation attention to prevent anthropogenic stressors from interfering
in the relationship balance between these sympatric predators.

The article can be downloaded at

Please feel free to email me if you have any questions: maricneves at gmail.com

Kind regards,

Msc. Mariana Cappello Neves

Ph.D. student
Programa de Pós-graduação em Oceanografia - UERJ
Laboratório de Mamíferos Aquáticos e Bioindicadores (MAQUA)
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