Variation in trophic resources in females South American sea lions at a small geographic scale

GRANDI, M. FLORENCIA; LOIZAGA, R.; CRESPO, E.A.; CRESPO, E.A.; VALES, D.; VALES, D.; GRANDI, M. FLORENCIA; LOIZAGA, R.

MARINE MAMMAL SCIENCE

WILEY-BLACKWELL PUBLISHING, INC

Lugar: Londres; Año: 2020 vol. 37 p. 314 - 327

0824-0469

Difference among colonies in the populationstructure of otariids can be driven by philopatry and/or by specializations inthe foraging ecology of females. In northern Patagonia, the South American sealion (SASL) shows some degree of spatial genetic structure among colonies fromnorth and south zones. This study aims to explore the isotopic niche of SASLfemales in the last period of the pregnancy from different colonies of northernPatagonia and to consider whether the fine scale genetic spatial structuring ispotentially related to variation in trophic resources. Stable isotope analysis wasperformed on 101 skin samples of newborn pups in 10 colonies, as a proxy for thefeeding ecology of their mothers. Differences among colonies in the metricsstudied revealed the plasticity of the species and support individual trophicspecialization of SASL females at a small geographic scale. Also, significantdifferences were found in all isotopic metrics between the north and southzones. Several hypotheses were proposed to explain the differences in SASLfemales? isotope values (e.g., use of different foraging areas or prey,isotopic baseline variation). Nonetheless, further research is needed to betterunderstand the relation between fine scale genetic structuring and the foragingecology of SASL females.