The diagram illustrates how the salmon's life cycle takes place.
Overall, the salmon's life cycle has 3 phases. It is immediately apparent that the salmon spend a half of their lives inhabiting in freshwater, while the other half is in the sea.
As shown in the diagram, in the upper , where the water flows slowly, countless salmon eggs are laid and incubated between reeds and small stones within about 5-6 months before hatching. In the next stage, they develop into tiny fish with the length from 3 to 8cm and migrate to the downstream river or estuary, where there is fast-flowing water for approximately 4 years.
It is clear from the diagram that in the Smolt stage, the young fish continue to grow in size, about 12 to 15cm, then migrate further downriver into the open sea which is their new habitat in roughly 5 years. After that, they grow into mature adult salmons and become much bigger in length, about 70-76cm. Finally, they swim against the river to the upstream region and start a new cycle life.