The brown trout (Salmo trutta) is a European species of salmonid fish (Salmonidae) that has been widely introduced into suitable environments globally. The native range of brown trouts extends from northern Norway and White Sea tributaries in Russia in the Arctic Ocean to the Atlas Mountains in North Africa. The western limit of Salmo trutta is Iceland in the north Atlantic, while the eastern limit is in Aral Sea tributaries in Afghanistan and Pakistan.