Southern elephant seals come ashore twice a year to breed and moult, with foraging periods at sea of more than 10 months. The adult males and females we tracked were satellite tagged at the southernmost breeding site of elephant seals on King George Island in 1997/98 and 2000/01 respectively. Both sexes moved far south into the deep pack ice - but to different feeding grounds: females moved along the shelf break west of the Antarctic Peninsula to forage for six months in the ice-covered Bellingshausen Sea, whereas males travelled into the Weddell Sea along the shelf break east of the Peninsula until they reached the region of the Filchner Trough outflow where they remained in a localized 100 km wide shelf-slope area for several winter months. Here the sea floor consists of canyons and ridges that support intensive mixing between the warm saline waters of the Weddell Gyre, the very cold outflow waters, and the ice shelf water at the Antarctic Slope Front. The Filchner region corresponds with one of the main source regions for the production of Weddell Sea Deep Water, being important for the export of Antarctic Bottom Water, a water body along which cold, dense and oxygenated water is exported from the Antarctic to the surrounding oceans initiating the global circulation.

The seals' area restricted movements in the Filchner region indicate active foraging in locally attractive feeding spots. The factors contributing to these hotspots of enhanced food availability are largely unexplored. What makes certain areas of the ocean better for foraging than others, and how stable are these feeding grounds over time? Are our findings of sex-specific use of different food habitats reproducible? To what degree are the seals' movements associated with hydrographic properties? What are oceanographic key features under the sea ice particularly in wintertime, and how do the seals respond to the distribution and extent of sea ice? These are some of the questions which form the basis of our interdisciplinary approach with physical and biological oceanographers, zooplankton and fishery biologists and specialists in remote sensing technology. Combination of observational data with proxy data such as sea-ice concentration, bathymetry and sea-surface height will allow extension of the findings into regions hitherto unobserved.

A commensurate research approach is being carried out by Prof. Dr. Marthan Bester and co-workers of the Mammal Research Institute at the University of Pretoria, RSA, at Marion Island. Our collaboration with Prof. Bester and his team has resulted in several joint expeditions since 1998 and is being continued as a long term collaboration project. Here we focus on synoptic analyses and syntheses of data on the foraging ecology of southern elephant seals in two different regions of the Southern Ocean.