This is a general account of the scientific investigations carried out in cruises between Cape Town and So. Georgia, the So. Shetland, and the Falkland Islands 1925-1927. Hydrographic, chemical, and planktonic observations were made as a basis for a scientific study of the whaling industry of this region. Vertical distribution of plankton down to considerable depths at several stations was ascertained by means of a closing net, and a large amount of material was obtained at the surface with a continuous plankton recorder. Plankton was most abundant near So. Georgia. Euphausia superba was obtained in great abundance off the northeast coast of the island; the So. Georgia blue, fin, and humpback whales feed exclusively on this crustacean.