Southern Ocean Southern Hemisphere, with the greatest concentration located on and around Antarctica. Four of the 18 penguin species live and breed on the mainland and its close offshore islands. Another four species live on the subantarctic islands. Emperor penguins have four overlapping layers of feathers, keeping them warm. They are the only Antarctic animal to breed during the winter. There are relatively few fish species in few families in the Southern Ocean. The most species-rich family are the snailfish (Liparidae), followed by the cod icefish (Nototheniidae) and eelpout (Zoarcidae). Together the snailfish, eelpouts and notothenioids (which includes cod icefish and several
Flightless cormorant A large oil spill would pose a threat. However, although the flightless cormorant population is small and its range limited, the ability of the species to breed quickly can allow it to recover from disasters as long as the population remains above a critical level. The flightless cormorant is one of the world's rarest birds. A survey carried out by the Charles Darwin Research Station in 2004 indicated that the species has a population of about 1,500 individuals. In 2009, BirdLife International set the number of individuals of the flightless cormorant at only 900 individuals, although a more recent estimate