[MARMAM] New publication on foraging ecology of South American fur seals

Renan Lima renancdl at gmail.com
Sat Oct 16 06:52:13 PDT 2021

Dear MARMAM community,

On behalf of my co-authors, I am pleased to announce that our newest paper
in Aquatic Ecology is now online:

"Segregation of diets by sex and individual in South American fur seals"
RC de Lima, V Franco-Trecu, TS Carrasco, P Inchausti, ER Secchi, S Botta

Trophic niche width and individual specialization among marine predators
are often subjected to seasonal constraints. Differences are expected to
arise for sexually dimorphic species exposed to distinct ecological
opportunities, as well as intrinsic differences in physiological abilities
or energetic requirements. We assess seasonal and sexual differences in
isotopic niche overlap and width and analyze inter-individual foraging
variation throughout the year of the South American fur seal (Arctocephalus
australis). We obtained chronologically ordered δ13C and δ15N data from
vibrissae of 25 males and 24 females from southern Brazil and Uruguay.
There were significant differences between sexes for both isotopes with
males showing higher values (δ13C = − 14.5 ± 0.5‰; δ15N = 18.9 ± 1.2‰) than
females (δ13C = − 15.2 ± 0.5‰; δ15N = 17.8 ± 1.2‰), but not among seasons
or years. A very small isotopic niche overlap found between sexes
(1.1–9.5%), with limited seasonal variation, likely resulted from
differences in prey consumption and foraging habitats. Compared to other
seasons, females had a wider isotopic niche in spring. While males showed
seasonal stability in the foraging niche, females showed some small
variation, which is probably influenced by central place foraging. Both
sexes had considerable interindividual variation in estimated dietary
composition and had different proportions of potential prey contribution at
the population level. These findings enlighten the knowledge of South
American fur seal trophic ecology, and how they may seasonally and
spatially shift their foraging strategies according to their distinct life
histories. It ultimately reflects in a small niche partitioning and
possibly low intraspecific competition at the species northernmost area of
occurrence in the western South Atlantic.

Please feel free to contact me via email (renancdl at gmail.com) for any
questions or a pdf copy of the paper.

Best regards,
Renan Lima

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: +55(53)99718994
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