Population Demographics for St Joseph, Minnesota in 2016 and 2015.
Princeton's WordNet(0.00 / 0 votes)Rate this definition: 1  spawn(verb) the mass of eggs deposited by fish or amphibians or molluscs. 2  engender, breed, spawn(verb) call forth. 3  spawn(verb) lay spawn. The salmon swims upstream to spawn.
Quick Answer. Salmon jump to clear obstacles in their path while travelling to their spawning grounds. Salmon hatch in freshwater rivers and then swim downstream to reach the ocean, where they mature. When they reach adulthood, the salmon swim back upstream to reach the spawning grounds where they hatched.