A group of salmon is called a run, a term that captures one of the most extraordinary journeys in the animal kingdom. Salmon are anadromous fish, meaning they’re born in freshwater rivers, migrate out to the ocean to grow and mature, and then return, often to the exact stream where they hatched, to spawn.
This return migration is exactly what’s meant by a “run”: massive numbers of salmon swimming upstream together, often against strong currents and over obstacles like waterfalls and rapids, driven entirely by instinct to reach their spawning grounds. Salmon runs can involve staggering numbers of fish and are a critical food source for bears, eagles, and other wildlife along their migration routes, making them a cornerstone event for entire ecosystems.
The physical toll of a salmon run is immense. Many species stop eating entirely once they enter freshwater, relying on stored energy to complete the journey and spawn, after which most Pacific salmon species die, having completed their single, singular purpose.