<P> Salmon / ˈsæmən / is the common name for several species of ray - finned fish in the family Salmonidae . Other fish in the same family include trout, char, grayling and whitefish . Salmon are native to tributaries of the North Atlantic (genus Salmo) and Pacific Ocean (genus Oncorhynchus). Many species of salmon have been introduced into non-native environments such as the Great Lakes of North America and Patagonia in South America . Salmon are intensively farmed in many parts of the world . </P> <P> Typically, salmon are anadromous: they hatch in fresh water, migrate to the ocean, then return to fresh water to reproduce . However, populations of several species are restricted to fresh water through their lives . Various species of salmon display anadromous life strategies while others display freshwater resident life strategies . Folklore has it that the fish return to the exact spot where they hatched to spawn; tracking studies have shown this to be mostly true . A portion of a returning salmon run may stray and spawn in different freshwater systems . The percent of straying depends on the species of salmon . Homing behavior has been shown to depend on olfactory memory . Salmon date back to the Neogene . </P> <P> The term "salmon" comes from the Latin salmo, which in turn might have originated from salire, meaning "to leap". The nine commercially important species of salmon occur in two genera . The genus Salmo contains the Atlantic salmon, found in the north Atlantic, as well as many species commonly named trout . The genus Oncorhynchus contains eight species which occur naturally only in the North Pacific . As a group, these are known as Pacific salmon . Chinook salmon have been introduced in New Zealand and Patagonia . Coho, freshwater sockeye, and Atlantic salmon have been established in Patagonia, as well . </P> <Table> <Tr> <Td> This article is part of a series on </Td> </Tr> <Tr> <Th> Commercial fish </Th> </Tr> <Tr> <Td> </Td> </Tr> <Tr> <Th> Large pelagic </Th> </Tr> <Tr> <Td> <Ul> <Li> billfish </Li> <Li> bonito </Li> <Li> mackerel </Li> <Li> salmon </Li> <Li> shark </Li> <Li> tuna </Li> </Ul> </Td> </Tr> <Tr> <Th> Forage </Th> </Tr> <Tr> <Td> <Ul> <Li> anchovy </Li> <Li> herring </Li> <Li> menhaden </Li> <Li> sardine </Li> <Li> shad </Li> <Li> sprat </Li> </Ul> </Td> </Tr> <Tr> <Th> Demersal </Th> </Tr> <Tr> <Td> <Ul> <Li> cod </Li> <Li> eel </Li> <Li> flatfish </Li> <Li> pollock </Li> <Li> ray </Li> </Ul> </Td> </Tr> <Tr> <Th> Mixed </Th> </Tr> <Tr> <Td> <Ul> <Li> carp </Li> <Li> tilapia </Li> </Ul> </Td> </Tr> <Tr> <Td> <Ul> <Li> </Li> <Li> </Li> <Li> </Li> </Ul> </Td> </Tr> </Table>

How many types of salmon fish are there