There are 18 seal species still inhabiting the seas today, but not long ago there were 19 species. Seals can be found in all the oceans and a few freshwater lakes, one of which is Lake Baikal in Russia. The Caribbean monk seal was last sighted in 1952 and is now listed as extinct. One of the seal species on the endangered species list is the Hawaiian monk seal (Monachus schauinslandi). The United States is one of many nations that are actively attempting to protect and bring back a healthy population of this endangered seal species.