eCite Digital Repository

Antarctic fur seals foraging in the Polar Frontal Zone: inter-annual shifts in diet as shown from fecal and fatty acid analyses


Lea, MA and Cherel, Y and Guinet, C and Nichols, PD, Antarctic fur seals foraging in the Polar Frontal Zone: inter-annual shifts in diet as shown from fecal and fatty acid analyses, Marine Ecology Progress Series, 245 pp. 281-297. ISSN 0171-8630 (2002) [Refereed Article]

DOI: doi:10.3354/meps245281


We studied the dietary preferences of Antarctic fur seals Arctocephalus gazella from Cap Noir, Îles Kerguelen, foraging in the Antarctic Polar Frontal Zone (PFZ) in February of 1998, 1999 and 2000. Scats were collected and analyzed for remaining prey hard parts in each of the 3 years, and in 1999 and 2000, the fatty acid (FA) composition of fur seal milk samples was also examined for longer-term dietary preferences. Scat analyses revealed that seals foraged primarily on fish and some squid in all 3 years with 25 species of fish being taken during the study. Myctophid fish accounted for an average of 94 % by number of all fish consumed with 3 species, Gymnoscopelus nicholsi, G. piabilis and Electrona subaspera, forming the core diet. Inter-annual differences in dietary species composition were apparent, however, with the presence of the mackerel icefish Champsocephalus gunnari in 1998 and the myctophid Protomyctophum tenisoni in 1999 accounting primarily for the differences observed between years. While reconstituted prey biomass per scat was similar between years, scats from 1998 represented less energy per gram than those from 1999 and 2000. This study highlights the usefulness of using FA signature analysis to confirm longer-term shifts in dietary intake of fur seals using milk samples. Polyunsaturated fatty acids (PUFAs) were significantly more prevalent in the 1999 milk samples, which were also lower in overall lipid content (43% vs 53%). G. nicholsi, a particularly oily fish, occurred in higher proportions in the diet in 2000, perhaps explaining the higher incidence of monounsaturated fatty acids (MUFAs) in this year and the generally higher lipid levels present in milk samples. The inter-annual variation in the diet of Antarctic fur seals confirmed by these 2 techniques lends support to the hypothesis that previously identified variations in oceanographic conditions surrounding Îles Kerguelen in 1998, 1999 and 2000 affect the availability of fur seal prey resources.

Item Details

Item Type:Refereed Article
Research Division:Environmental Sciences
Research Group:Environmental management
Research Field:Wildlife and habitat management
Objective Division:Environmental Management
Objective Group:Coastal and estuarine systems and management
Objective Field:Assessment and management of coastal and estuarine ecosystems
UTAS Author:Lea, MA (Professor Mary-Anne Lea)
ID Code:25180
Year Published:2002
Web of Science® Times Cited:86
Deposited By:Zoology
Deposited On:2002-08-01
Last Modified:2011-08-02

Repository Staff Only: item control page