They must be instinctive. Sexual maturity can be achieved at the age of 2 ~ 4 years. After sexual maturity, salmon begins to migrate to the river to lay eggs. In the process of migration, they gradually complete the development of sperm eggs, and when they come to the spawning ground, the sperm eggs are mature. In the process of salmon going upstream, it eats nothing and relies entirely on its rich nutrition to fight the waves. At this time, the female fish is chasing the tail of the male fish, commonly known as "biting patrol." When a male fish is bitten by a female fish, there will be foam. After the female fish sucks, the pregnant eggs begin to hatch, but the female fish still chases day and night. Only when she reached the beach did she stop swimming. The female fish beat the gravel with her tail fin and formed an egg hole by the impact of the current, commonly known as "patrol field". After ovulation and fertilization, the female fish cover the fertilized egg with gravel on the tail fin, and the male and female fish wander around the spawning hole (around the patrol field). When they were exhausted and died in the cave, their short lives passed by in such a hurry. In the second year, the fertilized egg melted and the embryo hatched. The small fish stayed in the "patrol farm" for a month or two, began to feed, and soon drifted into the sea.

After a long journey, coupled with long-term lack of food and physical exertion during breeding, the parent salmon died after spawning.