The diet of the Antarctic fur seal Arctocephalus gazella at the South Orkney Islands in ten consecutive years

RICARDO CASAUX; MARIANA A. JUARES; ALEJANDRO R. CARLINI; ALDO CORBALÁN

POLAR BIOLOGY

SPRINGER

Lugar: Berlin; Año: 2016 vol. 39 p. 1197 - 1206

0722-4060

To improve the knowledge on the foraging behavior of the Antarctic fur seal, evaluate if changes in its diet are associated to changes in prey availability, and evaluate if fisheries had negative impacts on Antarctic fur seal populations, a total of 1359 scats of non-breeding males were collected in ten consecutive sampling periods between 1994 and 2003 at Laurie Island, South Orkney Islands. Antarctic krill was the most numerous prey throughout the sampling period followed in importance by fish prey. Antarctic krill also predominated by reconstructed mass, except during 1994 and 1998 when penguins were the most important prey, and during 1995 when fish dominated. Among fish, demersal-benthic species (mainly Gobionotothen gibberifrons, Chaenocephalus aceratus and Chionodraco rastrospinosus) dominated in the diet except in 1997, 1998, 1999 and 2002 when myctophids (mainly Gymnoscopelus nicholsi and Electrona antarctica) were the most important fish prey. In seasons when fish dominated the diet, the diet was primarily comprised of demersal species. Although our results are in overall agreement with previous studies, the contribution to the diet of the main preys changed throughout the sampling period probably in parallel with changes in prey abundances. According to our information on fish consumption, the fisheries carried out in the past have had negative impacts on seal populations from the South Orkney Islands.