Diet of lactating South American sea lions, as inferred from stable isotopes, influences pup growth

DRAGO, MASSIMILIANO; CARDONA, LUIS; AGUILAR, ALEX; CRESPO, ENRIQUE A.; AMEGHINO, SANTIAGO; GARCÍA, NÉSTOR

MARINE MAMMAL SCIENCE

WILEY-BLACKWELL PUBLISHING, INC

Año: 2010 vol. 26 p. 309 - 323

0824-0469

Serum and blood cell 13C and 15N signals from 26 suckling pups of the SouthAmerican sea lion from northern Patagonia were used as proxies of the compositionof their mothers? diet to test the hypothesis that the foraging habits of the motherinfluence pup growth. Samples of primary producers and the female potential preywere analyzed to establish baseline isotopic values and to determine energy density.Pups were weighed to determine specific growth rate. Individual variability infemale diet was large, probably as a consequence of dissimilarities in the foragingperformance that depends on the individual?s age, body size, and/or foraging skills.Growth of a pup was influenced by its mother?s diet, as pups of females mostlyrelying on pelagic offshore prey were found to grow faster than those of femalesbasing their diet on benthic coastal prey.