Dispersal patterns of South American sea lions (Otaria flavescens) in the Atlantic revealed by oxygen isotopes from bone carbonate

ZENTENO LISETTE; CRESPO ENRIQUE ALBERTO; GOODALL RAE NATALIE PROSSER; AGUILAR ALEJANDRO; OLIVEIRA LARISSA ROSA DE; DRAGO MAXIMILIANO; SECCHI EDUARDO; GARCÍA NÉSTOR ANÍBAL; CARDONA LUIS

JOURNAL OF ZOOLOGY (1987)

WILEY-BLACKWELL PUBLISHING, INC

Lugar: Londres; Año: 2013 vol. 291 p. 119 - 126

0952-8369

AbstractStable isotopes of oxygen have been widely used to reconstruct paleotemperaturesand to investigate the thermal environment of fishes and mollusks, but they haveonly occasionally been used as geographical markers in marine systems. As boneapatite grows at a constant temperature in marine mammals and food is the majorsource of water for these animals, particularly for pinnipeds, variations in the ratioof stable isotopes of oxygen (d18O) of bone apatite will likely reflect changes in thed18O values of diet, and thus of the surrounding water mass, despite the potentialconfounding role of factors as the proximate composition of diet, sex and bodysize. Here, we used the d18O values in bone apatite to investigate whether adultmales of South American sea lion (Otaria byronia), from three regions in southwesternAtlantic Ocean (Brazil, Patagonia and Tierra del Fuego in Argentina),used the same water masses to forage and whether differences exist in the watermasses used by sea lions differing according to sex and developmental stage.Statistically significant differences were observed among the d18O bone values ofadult males from the three regions, with those from Patagonia more enriched in18O, as expected from the d18Oseawater values. These results revealed restricted dispersalmovements of adult males between the three areas. On the other hand, adultmales and females from Patagonia did not differ in average d18Obone values, thusindicating the use of foraging grounds within the same water mass. Finally, thevariability in the d18Obone values of young of both sexes was much wider than theadults of the same sex from the same region, which suggests the existence of ajuvenile dispersal phase in both sexes, although much shorter in females than inmales. These results confirm the usefulness of stable isotopes of oxygen as habitatstracers in marine mammals.