Abstract
Salmon are very interesting fish with complicated life cycles. They are born and die in freshwater but can live in both freshwater and seawater and migrate between rivers and oceans. Salmon previously inhabited only cold-water regions of the Northern Hemisphere but have been transplanted to the Southern Hemisphere and are now distributed around the world, and these fish have an amazing ability to imprint and precisely home to their natal stream. This chapter describes the terminology and taxonomy of salmon and related species associated with their phylogenetic evolution, the salmon species found around the world, the life cycles of Pacific salmon with special reference to imprinting and homing migration, the migration of other important migratory fish species, and the impact of climate change on migratory fish.