South Georgia has been the site of a controlled commercial sealing industry since 1909. The Southern Elephant Seal (Mirounga leonina) is killed for the oil obtained from the processing of the skin and subcutaneous fat, in a manner similar to the processing of whale blubber.

The island is divided into four sealing divisions, each with an annual catch quota which is subject to revision if necessary at the completion of each season, depending on information obtained from the average age of the catch, and an annual population census. There are also reserve areas, in which commercial killing is prohibited and which provide controls for comparison between commercially exploited herds and those which are undisturbed. The latter begin to breed an earlier age, reach their peak breeding period earlier and bear a smaller ratio of cow to bull calves than the former. The total kill permissible over the last decade has remained at 6000 adult bull seals over 3·5 m in length. At present, the catch quotas in each division are as follows:

In 1949 the Australian National Antarctic Research Expeditions (ANARE) began a long-term ecological study of the Southern Elephant Seal (Mirounga leonina) at HeardIsland. The biologists devised a method of branding seals for individual recognition (Chittleborough and Ealey, 1953) which has been modified only in detail since then (Carrick and Ingham, 1962a). At Heard Island, pups were branded every year until 1953, but the study here came to an end with the closing of the ANARE station in 1955. At Macquarie Island, pups have been branded every year from 1951 to 1965, giving a sample of individuals of known age and known history.