Salmon is a general term for several salmon fishes, which are native to the Pacific Ocean and Atlantic Ocean. Since the Paleolithic Age, people carved salmon in caves as an artistic symbol and began to eat salmon.
Salmon usually has migratory characteristics. Take Pacific salmon as an example. After living in the ocean for several years, they will migrate in groups in summer or autumn, return to freshwater rivers or streams to lay eggs, and usually return to the same river or even the same place where they were born. Then they will go to the distant ocean until the breeding season comes back again and bring back nutrients from the ocean.
Later, due to the increasing demand for salmon, there were salmon breeding bases in freshwater areas all over the world.
There are many kinds of salmon, such as Atlantic salmon. Different kinds of salmon may be different in appearance, growth environment and habits.
If you want to know more about salmon, you can consult relevant zoological materials or consult professional aquaculture personnel.