A population decline in Weddell seals: real or sampling artefact?

Abstract

Aerial counts of Weddell seals during the moult did not provide a useful index of population trends. Seals may spent longer foraging in the water in some years than in others (possibly because of changes in food availability), with the result that differing proportions of the population are counted in different years. It is concluded that little can be inferred about interannual differences in population sizes without reference to the size of the breeding population.