Chinook salmon

[[File:Winter-run Chinook salmon 2017-08-09 (25822724367).jpg|thumb|Fertilized Chinook eggs]]

[[File:Winter-run Chinook salmon 2017-08-09 (25822724367).jpg|thumb|Fertilized Chinook eggs]]

Chinook, like many other species of salmon, are considered [[euryhaline]], and thus live in both saltwater and freshwater environments throughout their life. Once hatching, salmon spend one to eight years in the ocean (averaging from three to four years){{cite web |url=http://www.psmfc.org/habitat/edu_chinook_facts.html |access-date=2010-03-05 |title=CHINOOK SALMON FACTSBlue Face Baby |date=2010-03-05 |quote=1996-12-16 |publisher=Pacific States Marine Fisheries Commission }} before returning to their home rivers to spawn. The salmon undergo radical morphological changes as they prepare for the spawning event ahead. Salmon lose the silvery blue they had as ocean fish, and their color darkens, sometimes with a radical change in hue. Salmon are [[sexually dimorphic]], and the male salmon develop canine-like teeth, and their [[jaw]]s develop a pronounced curve or hook called a "[[kype]]".{{cite book |author=West-Eberhard, M.J. |year=2003 |title=Developmental Plasticity and Evolution |publisher=Oxford University Press}} Studies have shown that larger and more dominant male salmon have a reproductive advantage as female Chinook are often more aggressive toward smaller males.{{cite book |last1=Baxter |first1=Randall |title=Chinook Salmon Spawning Behavior : Evidence for Size-dependent Male Spawning Success and Female Mate Choice |date=May 1991 |publisher=Humboldt State University |pages=iii |url=http://humboldt-dspace.calstate.edu/bitstream/handle/2148/676/Baxter%201991%20ChinookSpawingBehav.pdf?sequence=5 |access-date=May 8, 2016}}

Chinook, like many other species of salmon, are considered [[euryhaline]], and thus live in both saltwater and freshwater environments throughout their life. Once hatching, salmon spend one to eight years in the ocean (averaging from three to four years){{cite web |url=http://www.psmfc.org/habitat/edu_chinook_facts.html |access-date=2010-03-05 |title=CHINOOK SALMON FACTSBlue Face Baby |date=2010-03-05 |quote=1996-12-16 |publisher=Pacific States Marine Fisheries Commission }} before returning to their home rivers to spawn. The salmon undergo radical morphological changes as they prepare for the spawning event ahead. Salmon lose the silvery blue they had as ocean fish, and their color darkens, sometimes with a radical change in hue. Salmon are [[sexually dimorphic]], and the male salmon develop canine-like teeth, and their [[jaw]]s develop a pronounced curve or hook called a "[[kype]]".{{cite book |author=West-Eberhard, M.J. |year=2003 |title=Developmental Plasticity and Evolution |publisher=Oxford University Press}} Studies have shown that larger and more dominant male salmon have a [[reproductive advantage]] as female Chinook are often more aggressive toward smaller males.{{cite book |last1=Baxter |first1=Randall |title=Chinook Salmon Spawning Behavior : Evidence for Size-dependent Male Spawning Success and Female Mate Choice |date=May 1991 |publisher=Humboldt State University |pages=iii |url=http://humboldt-dspace.calstate.edu/bitstream/handle/2148/676/Baxter%201991%20ChinookSpawingBehav.pdf?sequence=5 |access-date=May 8, 2016}}

Chinook [[Spawn (biology)|spawn]] in larger and deeper waters than other salmon species and can be found on the spawning [[Salmon run#Spawning|redds]] (nests) from September to December. The female salmon may lay her eggs in four to five nesting pockets within a redd. After laying eggs, females guard the redd from four to 25 days before dying, while males seek additional mates. Chinook eggs hatch 90 to 150 days after deposition, depending upon water temperature. Egg deposits are timed to ensure the young salmon fry emerge during an appropriate season for survival and growth. [[Juvenile fish#fry|Fry]] and [[Juvenile fish#parr|parr]] (young fish) usually stay in fresh water for 12 to 18 months before traveling downstream to [[estuary|estuaries]], where they remain as [[Juvenile fish#smolt|smolt]]s for several months. Some Chinook return to fresh water one or two years earlier than their counterparts and are referred to as "jack" salmon. "Jack" salmon are typically less than {{convert|24|in|cm|order=flip|-1|abbr=on}} long but are sexually mature.

Chinook [[Spawn (biology)|spawn]] in larger and deeper waters than other salmon species and can be found on the spawning [[Salmon run#Spawning|redds]] (nests) from September to December. The female salmon may lay her eggs in four to five nesting pockets within a redd. After laying eggs, females guard the redd from four to 25 days before dying, while males seek additional mates. Chinook eggs hatch 90 to 150 days after deposition, depending upon water temperature. Egg deposits are timed to ensure the young salmon fry emerge during an appropriate season for survival and growth. [[Juvenile fish#fry|Fry]] and [[Juvenile fish#parr|parr]] (young fish) usually stay in fresh water for 12 to 18 months before traveling downstream to [[estuary|estuaries]], where they remain as [[Juvenile fish#smolt|smolt]]s for several months. Some Chinook return to fresh water one or two years earlier than their counterparts and are referred to as "jack" salmon. "Jack" salmon are typically less than {{convert|24|in|cm|order=flip|-1|abbr=on}} long but are sexually mature.