After salmon spawn and the eggs hatch what percentage of young fish survive to spawn eight years later

30 to 70% survive.

Explanation:

The term "spawning" refers to the moment when in the water environment the female fish deposit their eggs in the water while the male fish deposit the seed to fertilize them. After a period of time, these eggs hatch and the larvae of fish that must grow and develop in order to continue the process of species reproduction leave.

However, depending on the environment and the amount of natural enemies, not all fish larvae will be able to grow and develop. It is believed that only 30-70% of them reach the reproductive stage.

segmented body, an exoskeleton made from chitin, and joint appendages.