CHANGES IN POPULATION SIZES AND DISTRIBUTION OF FUR SEALS AT MARION ISLAND

Population censuses of the Antarctic fur seal (Arctocephalus gazella) and the sub-Antarctic fur seal (A. tropicalis) were conducted during t he 1994/1995 breeding season at Marion Island. Pup numbers, determined from direct counts and a mark-recapture experiment, were used to esti mate population sizes. Pup numbers of A. tropicalis showed a mean annu al change of 2.0% over the previous 6 years, culminating in an estimat ed total population of 49,523 for 1994/1995. The population appears to be entering the maturity phase of population growth and may therefore have recovered from the effects of uncontrolled sealing that ended in the early twentieth century. Numbers at the major colonies on Marion Island showed little change since 1989 and these sites may have reache d carrying capacity. The extension of breeding to other parts of the i sland continues. Over the same period, A. gazella pup numbers showed a mean annual change of 17% and the total population numbered 1,205 in 1994/1995. This species has possibly entered the rapid recolonisation phase of population growth. A few hybrid seals were found.