OVER-WINTER MOVEMENTS AND DIVING BEHAVIOR OF FEMALE WEDDELL SEALS (LEPTONYCHOTES-WEDDELLII) IN THE SOUTHWESTERN ROSS SEA, ANTARCTICA

The movements and diving behavior of 18 adult female Weddell seals (Le ptonychotes weddellii) were determined by satellite telemetry during t he over-winter period in 1990 and 1991. Nine seals provided diving and movement data for 8-9 months. Seals that normally bred in the eastern part of McMurdo Sound spent most of the winter in the middle and nort hern parts of McMurdo Sound before the annual shore-fast ice had forme d in those areas, or in the pack ice 0-50 km north of the sound and Ro ss Island. This is a greater use of pack ice, as opposed to shore-fast ice, in winter than was previously believed. Some long-distance movem ents (one over 1500 km in total) to the middle and northwestern parts of the Ross Sea also occurred. Although highly variable within and bet ween individuals, dives indicative of foraging were primarily to midwa ter regions (100-350 m) in both years, and were similar to those that have been observed in spring and summer, when Pleuragramma antarcticum is the primary prey of Weddell seals in McMurdo Sound.