Chinook salmon have seventeen distinctive runs in California. These runs vary in many ways, and are categorized into six evolutionarily significant units. Some units have been listed as threatened species. Fall-run Chinook salmon from the Mokelumne River are spawned and reared at the Mokelumne River Hatchery.
Steelhead trout are an anadromous form of the rainbow trout that go to the ocean for one or more years and then return to spawn upstream, similar to a salmon. They differ from salmon in that a steelhead may spawn and return to the ocean, and then spawn again in another year.
Mokelumne River Hatchery main page