Fish have a special ability. If they are moved from somewhere in the river to another section upstream or downstream, people will find that they will definitely swim back to their original place. This ability is called return performance.
According to research by scientists, the return performance of fish is the fish’s response to the unique smell of the water body in the river section where it originally lived. Young salmon are born in the river and enter the ocean to grow and develop. Mature salmon can still return to the place of their birth after living in the ocean for several years. Scientists have discovered that when a young fish leaves its place of birth, it remembers the special faint smell of the water where it was born. Therefore, when it grows up, it will definitely return to the water that exudes this faint smell to lay eggs.
Scientists also discovered that the faint odor that affects the return of fish to their homes is similar to the properties of a synthetic substance, morpholine. The smell of morpholine can overwhelm the natural "rustic smell", so it is possible to use morpholine to control and change the migration routes and spawning sites of fish.
