According to the Ca DFW, there are 17 distinct runs. These are classified on the DFW website as follows:
California streams support the southern-most Chinook salmon runs on the west coast. Chinook salmon in California display a wide array of life history patterns that allow them to take advantage of the diverse and variable riverine and ocean environments. Chinook salmon are “anadromous” fish, migrating upstream as adults to spawn in freshwater streams, and migrating as juveniles downstream to the ocean to grow and mature. The time spent in the ocean and freshwater varies greatly among the various runs. At least seventeen distinct runs of Chinook salmon are recognized in California . These runs have been classified into six major groups, or Evolutionarily Significant Units.
Southern Oregon and Northern California Coastal Chinook Salmon
The Southern Oregon and Northern California Coastal Chinook salmon ESU includes fall-run Chinook salmon in coastal streams from Cape Blanco in Oregon south to the Klamath River. Southern Oregon and Northern California Coastal Chinook salmon were proposed for federal listing in 1999, but listing was determined to be not warranted.
California Coastal Chinook Salmon
The California Coastal Chinook salmon ESU includes all; naturally spawned populations of Chinook salmon from rivers and streams south of the Klamath River to the Russian River, California, as well as seven artificial propagation programs: the Humboldt Fish Action Council (Freshwater Creek), Yager Creek, Redwood Creek, Hollow Tree, Van Arsdale Fish Station, Mattole Salmon Group, and Mad River Hatchery fall-run Chinook hatchery programs.
Due to concern over depressed population sizes relative to historical abundance, California Coastal Chinook salmon were federally listed as threatened in 1999.
Upper Klamath - Trinity River Chinook Salmon
Fall, late-fall, and spring-run Chinook spawn and rear in the Trinity River and in the Klamath River upstream of the mouth of the Trinity River. In the Trinity River, Chinook salmon spawn in the mainstem (with their upstream distribution limited by Lewiston Dam), the north and south forks, Hayfork Creek, New River, and Canyon Creek. In the Klamath River, Chinook salmon once ascended into Upper Klamath Lake, Oregon, to spawn in the major tributaries to the lake (Williamson, Sprague, and Wood Rivers), but access to this region was blocked by Copco Dam, built in 1917. Today Chinook are known to spawn in the mainstem Klamath River, Bogus Creek, Shasta River, Scott River, Indian Creek, Elk Creek, Clear Creek, Salmon River, Bluff Creek, Blue Creek, and the lower reaches of some of the other smaller tributaries to the mainstem river.
Upper Klamath – Trinity River Chinook salmon were proposed for federal listing in 1998, but listing was determined to be not warranted.
Central Valley Fall and Late Fall-run Chinook Salmon
Four distinct runs of Chinook salmon spawn in the Sacramento-San Joaquin River system, named for the season when the majority of the run enters freshwater as adults. Fall-run Chinook migrate upstream as adults from July through December and spawn from early October through late December. The timing of runs varies from stream to stream. Late fall-run Chinook migrate into the rivers from mid-October through December and spawn from January through mid-April. The majority of young salmon of these races migrate to the ocean during the first few months following emergence, although some may remain in freshwater and migrate as yearlings.
Fall-run Chinook are currently the most abundant of the Central Valley races, contributing to large commercial and recreational fisheries in the ocean and popular sportfisheries in the freshwater streams. Fall-run Chinook are raised at five major Central Valley hatcheries which release more than 32 million smolts each year. Due to concerns over population size and hatchery influence, Central Valley fall/late fall-run Chinook salmon are a Species of Concern under the federal Endangered Species Act.
Central Valley Spring-run Chinook Salmon
Four distinct runs of Chinook salmon spawn in the Sacramento-San Joaquin River system, named for the season when the majority of the run enters freshwater as adults. Spring-run Chinook enter the Sacramento River from late March through September. Adults hold in cool water habitats through the summer, then spawn in the fall from mid-August through early October. Spring-run juveniles migrate soon after emergence as young-of-the-year, or remain in freshwater and migrate as yearlings.
Spring-run Chinook were historically the most abundant race in the Central Valley. Now only remnant runs remain in Butte, Mill, Deer, Antelope, and Beegum Creeks, tributaries to the Sacramento River. In the mainstem Sacramento River and the Feather River, early-running Chinook salmon occur, but significant hybridization with fall-run has occurred. Due to the small number of non-hybridized populations remaining and low population sizes, Central Valley spring-run were listed as threatened under both the state and federal endangered species acts in 1999.
Sacramento River Winter-run Chinook Salmon
Four distinct runs of Chinook salmon spawn in the Sacramento-San Joaquin River system, named for the season when the majority of the run enters freshwater as adults. Adult winter-run pass under the Golden Gate Bridge from November through May, and pass into the Sacramento River from December through early August. Winter-run Chinook spawn in the upper mainstem Sacramento River from mid-April through August. Fry and smolts emigrate downstream from July through March through the Sacramento River, reaching the Delta from September through June.
Historically, winter-run Chinook spawned in the upper reaches of Sacramento River tributaries, including the McCloud, Pit, and Little Sacramento Rivers. Shasta and Keswick dams now block access to the historic spawning areas. Winter-run Chinook, however, were able to take advantage of cool summer water releases downstream of Keswick Dam. In the 1940’s and 1950’s the population recovered. However, beginning in 1970, the population experienced a dramatic decline, to a low of approximately 200 spawners by the early 1990’s. The run was classified as endangered under the state Endangered Species Act in 1989, and as endangered under the federal Endangered Species Act in 1994