Intraspecific differences in the diet of Antarctic fur seals at Nyrøysa, Bouvetøya

• Published in: Polar biology 2010-09, Vol.33 (9), p.1171-1178
• Main Authors: Hofmeyr, G. J. Greg, Bester, Marthán N, Kirkman, Steve P, Lydersen, Christian, Kovacs, Kit M
• Format: Article
• Language: English
• Subjects: Analysis; Animal and plant ecology; Animal behavior; Animal populations; Animal, plant and microbial ecology; Aquatic mammals; Biological and medical sciences; Biomedical and Life Sciences; Diet; Ecology; Foraging behavior; Fundamental and applied biological sciences. Psychology; Gender differences; Life history; Life Sciences; Marine mammals; Microbiology; Oceanography; Offspring; Original Paper; Otoliths; Particular ecosystems; Plant Sciences; Prey; Sea water ecosystems; Seals; Sexual behavior; Synecology; Zoology
• ISSN: 0722-4060; 1432-2056
• DOI: 10.1007/s00300-010-0805-0

Intraspecific differences in the diets of many species of pinnipeds are to be expected in view of the great differences in morphology, life history and foraging behaviour between the sexes of many species. We examined the diet of the Antarctic fur seal population at Bouvetøya, Southern Ocean, to assess intersexual differences. This was made possible by the analysis of prey remains extracted from scats and regurgitations collected in areas used primarily by one or the other sex. The results indicate that both males and females feed primarily on Antarctic krill Euphausia superba with several species of fish and squid being taken, likely opportunistically given their prevalence. Significant differences were identified in the frequency of occurrence of otoliths in scats and the percentage numerical abundance of the major fish prey species in the diet. Adult males ate a smaller quantity of fish overall, but ate significantly more of the larger fish species. The greater diving capabilities of males and the fact that they are not limited in the extent of their foraging area by having to return regularly to feed dependant offspring may play a role in the differences found between the diets of males and females. Additionally, females might be more selective, favouring myctophids because they are richer in energy than krill. The absence of major differences in the diet between the sexes at this location is likely due to the high overall abundance of prey at Bouvetøya.