Salmo

Salmo is a genus of ray-finned fish in the subfamily Salmoninae of family Salmonidae, most of whose members are commonly called trout; the exact number of species and subspecies is debated, with roughly 50 named taxa recognized including two known only from fossils. Nearly all Salmo species are confined to the Old World, across Europe, coastal North Africa and parts of West Asia around the Black Sea, the exception being the Atlantic salmon, which also occurs naturally in eastern North America. The Atlantic salmon and brown trout are widespread and have been introduced globally for farming and sport fishing, while most other Salmo species are narrowly distributed, each endemic to a single watershed; the genus fossil record extends back to the Middle Miocene.