Adult female southern elephant seals are predominantly pelagic, coming ashore biannually solely to breed and to moult. The success of the post-moult foraging trip has direct implications for female breeding success and the final weaning weight and future survival of the pup and may impact population fluctuations. In 2007 and 2008, a total of 13 post-moult adult female southern elephant seals from sub-Antarctic Marion Island were tracked via satellite transmitters. Ten of the resulting tracks were completed by recurrence of the female to Marion Island, with mean track durations of 250 days. The total trip distances ranged between 22 810.6 km and 13 169.7 km (mean = 18 980.9 km). Seals tracked in 2008 displayed longer total trip distances (20 450.6 km ± 5362.5 km) than seals tracked in 2007 (16 776.3 km ± 6106.5 km). The mean maximum distance attained was 2 793.9 km ± 845.6 km and did not vary between years. In contrast to southern elephant seals tracked from Kerguelen Island in 2003/2004, adult female seals (this study) travelled extensive distances due west of Marion Island. Only three individuals travelled to and within the Antarctic sea ice during the study period. The remaining animals travelled extensively along the South West Indian Ridge, often resulting in overlap of large portions of the tracks. Tracks displayed areas of restricted movement, which either coincided with areas of higher chlorophyll concentrations, anomalous sea-surface temperatures or mesoscale sea-surface height anomalies. An understanding of the relationships between southern elephant seal female movements and the variability of oceanographic features may help to identify driving forces of Marion Island southern elephant seal population fluctuations. Quantification of heterogeneity within marine habitats is thus necessary in order to further our understanding of such relationships.
Helmholtz Research Programs > PACES I (2009-2013) > TOPIC 1: The Changing Arctic and Antarctic > WP 1.6: Ocean Warming and Acidification: Organisms and their changing Role in Marine Ecosystems