A population study of Weddell seal in Lutzow-Holm Bay and its adjacent waters, Antarctica

A population study of the Weddell seal (Leptonychotes weddelli LESSON) was carried out in the fast ice area between 34°E and 44°30′E along the coastline of Lutzow-Holm Bay and the Prince Olav Coast, East Antarctica. The observations were made in April and in the period from September to December 1980. The study comprises ground survey and aerial census. The ground survey was done to obtain detailed information on the age and sex structures of the Weddell seal. It was made in a limited part of the area studied. The aerial census was undertaken to estimate the total population of seals in the whole of the area investigated and to examine their seasonal movement there. The Weddell seal began to appear on the ice in early spring and its population number reached a peak between October and November. The total seal population in the study area was estimated to be about 10000. The population density was 0.27/(km)^2. The population density in the Prince Olav Coast area was high compared with that in Lutzow-Holm Bay. It was higher in the coastal area than in the offshore area. A remarkable decrease of seal population in the coastal area and its increase in the offshore area occurred concurrently with the progress of the season