What is the act of migrating, or ascending a river to spawn; -- said of fish; also, an assemblage or school of fishes which migrate, or ascend a river for the purpose of spawning called?

run — The act of migrating, or ascending a river to spawn; -- said of fish; also, an assemblage or school of fishes which migrate, or ascend a river for the purpose of spawning. (Webster's 1913.)

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