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California Fish Website Species
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Chinook Salmon, Oncorhynchus tshawytscha
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Chinook salmon parr, approximately 10 cm
(4”) long. Location: Center for Aquatic Biology and Aquaculture, UC
Davis. Date: 5/21/2007. Thanks to Timothy Mussen.
This photo of a female spring-run Chinook salmon spawner was taken
by Lisa Thompson. Location: Butte
Creek, California.
Date: 9/16/2006. Thanks to Clint Garman, CDFG.
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Appearance
and Identification:
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Commonly 75-80 cm SL (9-10kg), sometimes exceeding 140 cm SL (45 kg)
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Various shades: white, pink, red
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Spots on both lobes of tail, black pigment along jaw
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Spawning adults olive brown or dark maroon, males darker
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Spawning males may have slightly hooked jaws and humped back
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Juvenile chinook: 6-12 large parr marks, window-like adipose fin with dark pigmented
edge, anal fin has white leading edge like coho, no black pigmented line
following
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Fin rays: dorsal 10-14, anal 14-19, pectoral 14-19, pelvic 10-11
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Lateral line scales:130-165 pored
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Life History:
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Chinook salmon are the largest of all the Pacific salmon
species and are thus commonly called king salmon. These fish are anadromous: they are born
and rear in freshwater, migrate to the ocean to feed, and return to their natal
streams to spawn and die. Two forms
of anadromy exist in the Chinook salmon,
specifically stream-type and ocean-type.
The duration of time spent in freshwater and then in saltwater
varies between types of anadromy and between
individual populations or runs of fish.
Stream-type Chinook salmon typically spend more than a year in
freshwater before swimming out to sea, where their stay will vary from one
to several years. Stream-type
Chinook salmon return to their natal streams in
spring or summer before reaching full maturity. The ocean-type Chinook salmon spend
several months to a year in freshwater before smoltification. The ocean phase then varies from one to
several years. Ocean-type Chinook
salmon return to their natal streams fully mature in August to
December. Within the classification
as stream or ocean-type Chinook salmon, fish may be further labeled based
upon the time of spawning, i.e. fall run, late fall run, winter run, or
spring run. The spawning fish
typically choose regions of deep pools with large rocky substrate. The female builds a series of nests or redds where she deposits a total of 2,000 to 17,000
eggs depending on body size. The
males fertilize the eggs, which will remain in the gravel for 40-60
days. When the alevins
hatch they remain in the safety of the substrate for another 4-6 weeks
while absorbing the nutrients of a yolk sac. When young Chinook salmon emerge as fry
they are typically swept down to areas of slower water velocities. Young
Chinook salmon tend to occupy a specific pool or area before moving
downstream to the ocean. Typically
small fry occupy the margins of a stream: back eddies, behind roots and
logs, and other areas of bank cover.
As the fish grow they begin to move into deeper and faster
water. Growth rates are largely
influenced by water temperature and the optimal range is 13-18°C. Young Chinook salmon will survive and
grow within the range of 5-19°C, whereas steady temperatures above 24°C are
lethal. Juveniles feed primarily on
drifting insects of different sizes and stages, though the Chinook salmon
may also consume zooplankton or fish larvae. Most feeding occurs at dawn and in the
afternoon when favored food sources are present in the water column. Throughout their residence in freshwater,
juvenile Chinook salmon feed opportunistically and the prey size remains
fairly constant. When Chinook salmon
reach the ocean, the salmon focus on a diet of crustaceans and other fish,
fueling rapid growth rates.
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Links to Other Research
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Here's a list of California
watersheds where Chinook
Salmon may be found.
© 2003 - Regents of the University
of California
Division of Agriculture and Natural Resources
Communication Services
E-Mail Web Master
ANR
Non-Discrimination Statement
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