Long-lived animals such as elephant seals may endure variation in food resources over large spatial and temporal scales. Understanding how they respond to these fluctuations requires knowledge of how their foraging behavior and habitat utilization varies over time. Advances in satellite-linked data logging have made it possible to correlate the foraging behavior of marine mammals with their ... physical and chemical environment and provide insight into the mechanisms controlling at-sea movements, foraging behavior and, ultimately, reproductive success of these pelagic predators. In addition, these technological advances enable marine mammals to be used as highly cost-effective platforms from which detailed oceanographic data can be collected on a scale not possible with conventional methods. The project will extend the four-year-time-series collected on the foraging behavior and habitat utilization of southern elephant seal (Mirounga leonina) foraging in the Western Antarctic Peninsula. It also will extend the oceanographic time-series of CTD profiles collected by the elephant seals foraging from the Livingston Island rookery. Seals have been collecting CTD profiles in the vicinity of the Wilkins Ice Shelf (WIS) since 2005. We thus have a 4 year data set that preceding and during the breakup of the WIS that occurred during March 2008. Deployment of additional tags on seals will provide a unique opportunity to collect oceanographic data after the ice shelf has collapsed.