Assessing the influence of blubber stratification on the estimation of diet in phocid seals using the MixSIAR model

Abstract Blubber stratification can significantly impact diet estimation, as using the inner or outer blubber layer may lead to different results depending on the degree of stratification present. We aimed to quantitatively evaluate the effect of blubber stratification on diet estimation at the popu...

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Main Authors: Antonia Carrasco-Cárdenas, Carmen Barrios-Guzmán, Javier Negrete, Tracey L. Rogers, Alicia I. Guerrero
Format: Article
Language:English
Published: Nature Portfolio 2025-07-01
Series:Scientific Reports
Online Access:https://doi.org/10.1038/s41598-025-07004-7
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author Antonia Carrasco-Cárdenas
Carmen Barrios-Guzmán
Javier Negrete
Tracey L. Rogers
Alicia I. Guerrero
author_facet Antonia Carrasco-Cárdenas
Carmen Barrios-Guzmán
Javier Negrete
Tracey L. Rogers
Alicia I. Guerrero
author_sort Antonia Carrasco-Cárdenas
collection DOAJ
description Abstract Blubber stratification can significantly impact diet estimation, as using the inner or outer blubber layer may lead to different results depending on the degree of stratification present. We aimed to quantitatively evaluate the effect of blubber stratification on diet estimation at the population and individual levels in two species of phocid seals: the leopard seal (Hydrurga leptonyx) and the crabeater seal (Lobodon carcinophaga), using the mixing model MixSIAR. In leopard seals, krill contributed most significantly to the diet based on the inner layer (68.2%), while Antarctic silverfish dominated the outer layer (59.2%). For crabeater seals, krill was the primary prey in both layers, but with different contributions (87.1% inner layer vs. 63.4% outer layer). Both species exhibited greater individual specialization according to the outer layer compared to the inner layer, suggesting lower individual variability in the summer than in winter, when it may increase due to reduced prey availability. These findings have implications for trophic studies in marine mammals, as the sampling method may lead to contrasting diet estimates, altering prey contribution percentages and their relative dominance, in particular in generalist species. In specialists with low stratification, however, the need to obtain the inner blubber for accurate results is reduced.
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spelling doaj-art-a58055f5f1744b92ad20a364984119172025-08-20T04:01:36ZengNature PortfolioScientific Reports2045-23222025-07-0115111310.1038/s41598-025-07004-7Assessing the influence of blubber stratification on the estimation of diet in phocid seals using the MixSIAR modelAntonia Carrasco-Cárdenas0Carmen Barrios-Guzmán1Javier Negrete2Tracey L. Rogers3Alicia I. Guerrero4Centro de Investigación y Gestión de Recursos Naturales (CIGREN), Instituto de Biología, Facultad de Ciencias, Universidad de ValparaísoCentro de Investigación y Gestión de Recursos Naturales (CIGREN), Instituto de Biología, Facultad de Ciencias, Universidad de ValparaísoDepartamento Biología de Predadores Tope, Instituto Antártico ArgentinoEvolution and Ecology Research Centre, School of Biological, Earth and Environmental Sciences, University of New South WalesCentro de Investigación y Gestión de Recursos Naturales (CIGREN), Instituto de Biología, Facultad de Ciencias, Universidad de ValparaísoAbstract Blubber stratification can significantly impact diet estimation, as using the inner or outer blubber layer may lead to different results depending on the degree of stratification present. We aimed to quantitatively evaluate the effect of blubber stratification on diet estimation at the population and individual levels in two species of phocid seals: the leopard seal (Hydrurga leptonyx) and the crabeater seal (Lobodon carcinophaga), using the mixing model MixSIAR. In leopard seals, krill contributed most significantly to the diet based on the inner layer (68.2%), while Antarctic silverfish dominated the outer layer (59.2%). For crabeater seals, krill was the primary prey in both layers, but with different contributions (87.1% inner layer vs. 63.4% outer layer). Both species exhibited greater individual specialization according to the outer layer compared to the inner layer, suggesting lower individual variability in the summer than in winter, when it may increase due to reduced prey availability. These findings have implications for trophic studies in marine mammals, as the sampling method may lead to contrasting diet estimates, altering prey contribution percentages and their relative dominance, in particular in generalist species. In specialists with low stratification, however, the need to obtain the inner blubber for accurate results is reduced.https://doi.org/10.1038/s41598-025-07004-7
spellingShingle Antonia Carrasco-Cárdenas
Carmen Barrios-Guzmán
Javier Negrete
Tracey L. Rogers
Alicia I. Guerrero
Assessing the influence of blubber stratification on the estimation of diet in phocid seals using the MixSIAR model
Scientific Reports
title Assessing the influence of blubber stratification on the estimation of diet in phocid seals using the MixSIAR model
title_full Assessing the influence of blubber stratification on the estimation of diet in phocid seals using the MixSIAR model
title_fullStr Assessing the influence of blubber stratification on the estimation of diet in phocid seals using the MixSIAR model
title_full_unstemmed Assessing the influence of blubber stratification on the estimation of diet in phocid seals using the MixSIAR model
title_short Assessing the influence of blubber stratification on the estimation of diet in phocid seals using the MixSIAR model
title_sort assessing the influence of blubber stratification on the estimation of diet in phocid seals using the mixsiar model
url https://doi.org/10.1038/s41598-025-07004-7
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