Winter use of sea ice and ocean water-mass habitat by southern elephant seals: The length and breadth of the mystery

•Time-series of 35 elephant seal winter foraging trips to Antarctica were analyzed.•A high resolution dive behaviour dataset was used to predict foraging events.•The links between foraging and sea ice, hydrography and topography were quantified.•Foraging strategies depended on the sex of seals.•The foraging activity was associated with a number of oceanographic discontinuities.