Salmon are a widely spread group of fish. They live most of their lives in the open ocean, but come to the lake of which they hatched to lay their own eggs. There are many species of salmon.
Salmon hatch in freshwater streams far inland. They spend the first few years of their life in lakes, pools, and small rivers; feeding off mayflies, insect larvae, and other small creatures. Then, they migrate to the Pacific ocean. They spend up to four years here, eating small fish. Then, they migrate back to the river from which they hatched. They navigate by using the Earths magnetic field and their incredible sense of smell. They swim upstream several hundred miles to spawn. They don’t eat during this entire journey. When they reach their spawning grounds, (often the same pool from which they hatched) they are weak and tired. The female digs a hole in the gravely bottom, then lays her eggs in it. She and her mate die soon afterwards.
Salmon have been a major food source for people for thousands of years. Native American tribes have caught salmon with nets, spears, and hooks to eat since about 3,000 BC. When Europeans came to America, they decimated salmon populations not only to eat. Deforestation heated up rivers and killed the salmon. Pollution from factories poisoned them. They almost went extinct because of this. Thanks to conservationists, healthy salmon populations can be found all along the west coast.