[MARMAM] New publication on South American fur seals individual variation in habitat and resource use

Renan Lima renancdl at gmail.com
Mon Feb 4 13:14:46 PST 2019

On behalf of my co-authors, I am pleased to announce the publication
of our research article "Individual foraging specialization and sexual
niche segregation in South American fur seals".

Lima, R.C., Franco-Trecu, V., Vales, D.G., Inchausti, P., Secchi,
E.R., and Botta, S. Individual foraging specialization and sexual
niche segregation in South American fur seals.


Individual variation in habitat and resource use has been reported for
many top predators. This variation becomes important when comparing
individuals taking into account sex, size, or age classes, since it
can influence population dynamics and stability. We evaluated the
individual variation and sexual/geographical isotopic niche overlap of
the South American fur seal (SAFS) from the western South Atlantic.
Whiskers of adult individuals from Brazil (n = 19), Uruguay (n = 29),
and Argentina (n = 5) collected between 2005 and 2016 were serially
sampled, resulting in 1001 samples, and their carbon and nitrogen
isotopic ratios were analyzed longitudinally. According to its length,
time integrated by whiskers ranged between 1.4 and 5.6 years. Males
had δ13C (− 14.5 ± 0.6‰) and δ15N (18.9 ± 1.2‰) values significantly
higher than females (δ13C = − 15.2 ± 0.5‰, δ15N = 17.8 ± 1.2‰).
Females from Uruguay and Brazil were isotopically similar, displaying
a large isotopic niche overlap (65.2–84%). Contrary, moderate isotopic
niche overlaps were observed between males from Uruguay and Brazil
(40.1–48.4%), and Uruguay and Patagonia (22.3–27.8%), indicating the
use of different prey and/or feeding grounds. The WIC/TNW index of
individual specialization pointed a significant specialization in
males (0.38 for δ15N and 0.39 for δ13C). Females, on the other hand,
are more generalists compared to males (0.53 and 0.71, for δ15N and
δ13C, respectively). Differences in the ecological opportunity between
sexes can account for these variations. Our study points out that
trophic generalist populations of SAFS are composed of specialist and
generalist individuals.

The article is available in:

You can also request a free pdf copy in my e-mail: renancdl at gmail.com

Best regards,


MSc Renan Costa de Lima
Doutorando do Programa de Pós-Graduação em Oceanografia Biológica
Laboratório de Ecologia e Conservação da Megafauna Marinha - EcoMega
Instituto de Oceanografia
Universidade Federal do Rio Grande (FURG)
Fone: (53) 99718994

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