How Do Salmon Find Their Way Back to Their Home River?

Pacific and Atlantic salmon hatch in freshwater streams, migrate to the ocean, and return years later to spawn. Research suggests young salmon imprint on the magnetic signature of the coast where they enter the sea and use it to find that region again. Once they reach the coast, they follow the unique chemical scent of their birth stream, which they memorised as juveniles. Some salmon travel over 1,000 kilometres upstream, leaping waterfalls and rapids along the way. Most Pacific salmon die shortly after spawning, and their bodies enrich the river ecosystem with ocean nutrients.