Central California Coast coho "run" upstream to their spawning grounds during the winter months. Although considered to have only one run, coho populations inhabiting coastal streams north of California may begin their migration earlier, with runs beginning in the fall or even late summer.
Central California Coast and South/Central California Coast steelhead are "winter run," which means that adults run (migrate) upstream to their spawning grounds during the winter season. Coastal streams north of San Francisco Bay may support a summer run, as well as the more common winter run.
*Steelhead juveniles may smolt their first year or spend up to three additional years rearing in freshwater before migrating to sea.