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How do salmon migrate between freshwater streams and the ocean during their life cycle?
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fish
Diodon hystrix is a species of porcupine fish. These fishes are short and broad-bodied, with large eyes and spines covering their skin. Like puffer fishes, they inflate their bodies when threatened.
Salmon are anadromous fish, meaning they are born in freshwater, migrate to the ocean to mature, and return to freshwater to spawn.1
The Life Cycle Journey
- Freshwater Beginnings: Salmon hatch in cold, clear streams or lakes. Depending on the species, they may remain in these freshwater environments for anywhere from a few weeks to several years before migrating seaward.12
- Ocean Maturation: Once they reach the ocean, salmon spend much of their adult lives there, growing and accumulating energy reserves in the form of oils.34
- The Return Migration: Driven by instinct, adult salmon return to their natal streams to spawn. This journey can span thousands of miles, requiring them to navigate rapids and waterfalls. During this phase, they stop eating and rely entirely on stored energy.324
- Navigation: Salmon use their sense of smell to identify the specific chemical signature of their home stream, a process aided by early-life imprinting. Some species, such as the sockeye, also utilize Earth’s magnetic field for navigation.12
Upon reaching their destination, salmon spawn in gravel beds. While many Pacific salmon die after this single, strenuous reproductive effort, some Atlantic salmon survive to return to the sea.124