Three species of pinnipeds breed and feed on the coasts of the Patagonian Sea: the South American Sea Lion (Otaria flavescens), the South American Fur Seal (Arctocephalus australis) and the Southern Elephant Seal (Mirounga leonina). A fourth species, the Antarctic Fur Seal (Arctocephalus gazella), forages in the area but breeds in South Georgia and other Antarctic islands.

The principal threat to pinnipeds is their interaction with fisheries and competition for food resources. Entanglement and incidental mortality in fishing gears are additional threats.