The slow-moving Humpback whale (Megaptera novaengliae), with its long knobbed flippers and hunched back, is occasionally to be seen close in to shore around the coasts, while the Southern Right whale (Eubalaena glacialis) is occasionally sighted around South Georgia, though it rarely enters polar waters.

All of these whales feed by filtering out plankton from the surface waters of the sea, using horny plates-baleen - hanging from the upper jaws as a filter bed, and by far the most important organism in their diet is krill.

However, they do not all feed indiscriminately: Sei whales, which have very fine baleen, take significant quantities of copepods, particularly in the more northerly part of their Antarctic distribution; Blue whales concentrate on first year krill with a length of 20-30mm; Fin whales take mostly second year krill 30-40mm long; Right whales have very long baleen plates and tend not to gulp at concentrations of plankton, as do the others, but feed continuously, skimming the surface waters and catching the dispersed organisms such as copepods.