What would happen if the number of salmon decreased

What would most likely occur is that the organisms that eat salmon would have less food to eat and if their food supply, in this case, salmon were to run out, they would die or they would have to find something else to eat. If the organism that eats the salmon dies, in this case we'll call that organism, organism A, any other organisms that eat organism A will die or will have to find another means of food. So basically it causes a disruption in the food chain which can lead to the extinction of different species