coho salmon

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| caption1 = Male (spawning phase), Oregon

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During their ocean phase, coho salmon have silver sides and dark-blue backs with spots on their back and upper tail lobe.{{Cite web |author=((NOAA Fisheries)) |date=2023-10-12 |title=Coho Salmon {{!}} NOAA Fisheries |url=https://www.fisheries.noaa.gov/species/coho-salmon |access-date=2024-02-12|website=NOAA |language=en}} During their spawning phase, their jaws and teeth become hooked. After entering fresh water, they develop bright-red sides, bluish-green heads and backs, dark bellies and dark spots on their backs. Sexually maturing fish develop a light-pink or rose shading along the belly, and the males may show a slight arching of the back. Mature adults have a pronounced red skin color with darker backs and spots, with females having darker shades than males.{{Cite journal |last1=Fleming |first1=Ian A. |last2=Gross |first2=Mart R. |date=January 1989 |title=Evolution of Adult Female Life History and Morphology in a Pacific Salmon (Coho: Oncorhynchus kisutch) |url=http://dx.doi.org/10.2307/2409170 |journal=Evolution |volume=43 |issue=1 |pages=141–157 |doi=10.2307/2409170 |jstor=2409170 |pmid=28568502 |issn=0014-3820|url-access=subscription }}

Coho salmon average 20 to 28 inches (50.8 to 71 cm) and {{convert|7|to|11|lb|kg}}, occasionally reaching up to {{convert|36|lb|kg}}. Size can vary depending on age and geographic location.{{Cite book |last1=Groot |first1=Cornelis |url=https://books.google.com/books?id=I_S0xCME0CYC&dq=Coho+Salmon&pg=PA397 |title=Pacific Salmon Life Histories |last2=Sandercock |first2=F.K. |date=1991 |publisher=UBC Press |isbn=978-0-7748-0359-5 |pages=397–444 |language=en}} Males tend to be slightly larger than females. Mature adults also develop a large kype (hooked beak) which is used to attract a mate during spawning, with males having a more pronounced kype than females.{{cite web |title=Coho Salmon |url=http://www.adfg.alaska.gov/static/education/wns/coho_salmon.pdf |access-date=18 March 2022 |website=Adfg.alaska.gov}}{{Cite web |title=Why do salmon change color and die after they spawn? {{!}} U.S. Geological Survey |url=https://www.usgs.gov/faqs/why-do-salmon-change-color-and-die-after-they-spawn#:~:text=Salmon%20change%20color%20to%20attract,to%20the%20ocean%20after%20spawning. |access-date=2023-11-17 |website=www.usgs.gov| date=14 July 2016 }} The coho salmon's lower jaw can be distinguished by a light shade at its superior edge.

File:My Public Lands Roadtrip- Counting Fish in the Salmon River in Oregon (19165618101).jpg

File:Dead salmon in spawning season.jpg

File:Silver Salmon at Smith River Falls (49021167137).jpg]]

Once the mature coho has reached three or four years old, it swims up freshwater rivers and streams to spawn (reproduce). Coho will swim up streams as far as they are physically able, usually reaching areas of water as little as {{convert|5|cm|in}} deep. Females seek out beds of gravel at the head of a riffle, where they turn on their sides to dig a nest with movements of their tail, creating round or oval depressions roughly the same lengths and width as the fish.{{cite book |last=Becker |first=George C. |date=1983 |title=Fishes of Wisconsin |url=https://search.library.wisc.edu/digital/AWFIWUVZSK4EFH9B |location=Madison, Wisconsin |publisher=University of Wisconsin Press |page=307-311 |isbn=978-0299087906 |url-status=live |archive-url=https://web.archive.org/web/20241115005747/https://search.library.wisc.edu/digital/AWFIWUVZSK4EFH9B |archive-date=15 Nov 2024 |access-date=22 Feb 2025}} This process is repeated for up to seven nests, each called a redd. Females become extremely aggressive with each other over nesting sites, and with males until these are dug. Males then fight for the right to mate. Once a female has chosen a mate, usually the largest male, she lays her eggs onto the redd, while he simultaneously releases milt (sperm) onto the eggs. Unchosen males also sneak in to release milt at this time. Once all eggs are laid, she covers them with rocks and pebbles using her tail. The adults then begin semelparity, whereby they stop eating and deteriorate to death.

{{See also|Salmon run}}

File:Smallmouth and coho (cropped).jpg and a rainbow trout]]

The eggs hatch in the late winter or early spring after six to seven weeks in the redd. Once hatched, they remain mostly immobile in the redd during the alevin life stage, which also lasts for six to seven weeks.{{cite web|url=https://www.parksconservancy.org/conservation/coho-salmon|title=Coho Salmon|website=Golden Gate National Parks Conservancy|year=2023|access-date=2024-02-12}} Alevin no longer have the protective egg shell, or chorion, and rely on their yolk sacs for nourishment during growth. The alevin life stage is very sensitive to aquatic and sedimental contaminants. When the yolk sac is completely resorbed, the alevin leaves the redd.{{Cite web |date=2009-02-25 |title=Columbia River Basin |url=http://www.blm.gov/education/00_resources/articles/Columbia_river_basin/posterback.html |access-date=2023-11-17 |archive-url=https://web.archive.org/web/20090225075127/http://www.blm.gov/education/00_resources/articles/Columbia_river_basin/posterback.html |archive-date=2009-02-25 }} Young coho spend one to two years in their freshwater natal streams, often spending the first winter in off-channel sloughs, before transforming to the smolt stage. Smolts are generally {{convert|100|-|150|mm|in|abbr=on}} and as their parr marks fade and the adult's characteristic silver scales start to dominate. Smolts migrate to the ocean from late March through July. Some fish leave fresh water in the spring, spend summer in brackish estuarine ponds, and then return to fresh water in the fall. Coho salmon live in salt water for one to three years before returning to spawn. Some precocious males, known as "jacks", return as two-year-old spawners. Spawning males develop kypes, which are strongly hooked snouts and large teeth.

File:Coho salmon fingerling (SC) 1.JPG|Fingerling

File:Lake Washington Ship Canal Fish Ladder pamphlet - ocean phase Coho.jpg|Male ocean phase coho

File:Lake Washington Ship Canal Fish Ladder pamphlet - male freshwater phase Coho.jpg|Male freshwater phase coho

File:Coho salmon.jpg, Alaska]]

File:Coho and Sockeye Salmon.jpg, Russian River, Alaska]]

The traditional range of the coho salmon runs along both sides of the North Pacific Ocean, from Hokkaidō, Japan and eastern Russia, around the Bering Sea to mainland Alaska, and south to Monterey Bay, California.{{cite journal |title=Coho Salmon Are Native South of San Francisco Bay: A Reexamination of North American Coho Salmon's Southern Range Limit |journal=Fisheries |date=September 2007 |pages=441–451 |doi=10.1577/1548-8446(2007)32[441:CSANSO]2.0.CO;2 |issn=1548-8446 |volume=32 |author=Peter B. Adams |issue=9|display-authors=etal}} Coho salmon have also been introduced in all the Great Lakes, as well as many landlocked reservoirs throughout the United States.{{Cite web|url=http://www.michigan.gov/dnr/0,4570,7-153-10364_18958-45666--,00.html|title=Coho Salmon, Oncorhynchus kisutch|website=Michigan.gov|access-date=18 March 2022}} Coho salmon were first introduced in Lake Erie in the 1920s to control the lake's alewife population. Large-scale stocking began in 1966, when 660,000 fingerlings were introduced in Lake Michigan. Wisconsin began a program of introduction of 500,000 fry a year, mainly on the coastline of Lake Michigan. By 1970, the species was present in all of the Great Lakes. Ontario and Minnesota adopted stocking programs in 1969, but later abandoned them. Colorado began stocking coho salmons in the early 1900s, although only limited reproduction is recorded in the Colorado River. Another stocking was done in New Hampshire in the late 1960s, which dispersed to Maine and Massachusetts and were recorded to engage in sporadic reproduction.{{cite web | url=https://nas.er.usgs.gov/queries/FactSheet.aspx?SpeciesID=908 | title=Coho Salmon (Oncorhynchus kisutch) - Species Profile }}

Natural reproduction in introduced areas is generally low. Limited self-sustaining populations are recorded in Lake Superior and Michigan, but the salmon does not reproduce naturally in the Wisconsin tributaries of Lake Michigan and relies on stocking to maintain a large population. The species is no longer stocked in Lake Erie, although stray individuals from elsewhere in the Great Lakes are caught on occasion. Efforts to establish the species in Connecticut began in the 1800s, but were discontinued when the species failed to establish a stable population. Introductions in Connecticut and Delaware also failed to found permanent populations.

Over twenty specimens were caught in waters surrounding Denmark and Norway in 2017. Their source is currently unknown, but the salmon species is farmed at several locations in Europe, making it probable that the animal has slipped the net at such a farm.{{cite news |title=Danish fishermen catch salmon not from Denmark |newspaper=The Local Denmark |date=27 September 2017 |access-date=26 October 2017 |url=https://www.thelocal.dk/20170927/danish-fishermen-catch-salmon-not-from-denmark |publisher=The Local}}

In their freshwater stages, coho feed on plankton and aquatic invertebrates in the benthos and water column, such as Chironomids, midge larvae, and terrestrial insects that fall into the water.{{cite journal |last1=Johnson |first1=James |last2=Ringler |first2=Neil |title=Diets of juvenile coho salmon (Oncorhynchus kisutch) and steelhead trout (Salmo gairdneri) relative to prey availability |journal=Canadian Journal of Zoology |date=1980 |volume=58 |issue=4 |pages=553–558 |doi=10.1139/z80-077|bibcode=1980CaJZ...58..553J }} Upon entering the marine environment, they switch to a diet of plankton and fish, with fish making up most of their diets after a certain size.{{cite journal |last1=Daly |first1=Elizabeth |last2=Brodeur |first2=Richard |last3=Weitkamp |first3=Laurie |title=Ontogenetic Shifts in Diets of Juvenile and Subadult Coho and Chinook Salmon in Coastal Marine Waters: Important for Marine Survival? |journal=Transactions of the American Fisheries Society |date=2009 |volume=138 |issue=6 |pages=1420–1438 |doi= 10.1577/T08-226.1|bibcode=2009TrAFS.138.1420D }} Introduced populations in the Great Lakes feed primarily on alewife and smelt. Great Lakes salmon are known to compete with native lake trout, brook trout, and brown trout for food and space when resources are scarce. Due to emerging earlier and having a larger hatching size, coho salmon typically have an advantage in these confrontations.

Salmonid species on the west coast of the United States have experienced dramatic declines in abundance during the past several decades as a result of human-induced and natural factors.{{cite web |url=http://www.nmfs.noaa.gov/pr/species/fish/salmon.htm |title=Pacific salmonids threats |date=9 July 2021 |publisher=U.S. National Marine Fisheries Service}}

File:Coho(=silver) salmon total production thousand tonnes 1950-2022.svg{{Cite web |title=Fisheries and Aquaculture - Global Production |url=https://www.fao.org/fishery/en/collection/global_production?lang=en |access-date=2024-05-06 |website=Food and Agriculture Organization of the United Nations (FAO)}}]]

The total North Pacific harvest of coho salmon in 2010 exceeded 6.3 million fish, of which 4.5 million were taken in the United States and 1.7 million in Russia. This corresponds to some 21,000 tonnes in all.[http://www.npafc.org/new/publications/Statistical%20Yearbook/Data/2010/2010page.htm Annual Statistics 2010: Commercial salmon catch by species and country] North Pacific Anadromous Fish Commission Statistical Yearbook. Retrieved 2015 March 16. These numbers do not include fish taken in Russian waters by foreign fleet. Coho salmon are the backbone of the Alaskan troll fishery, though the majority are caught by the net fishery (gillnet and seine fishing). They average 3.5% by fish and 5.9% by weight of the annual Alaska salmon harvest.(Alaska Seafood Marketing Institute, 2003, p. 2) The North Pacific yields of pink salmon, chum salmon and sockeye salmon are about 15 times larger by weight.

File:Coho on Bumper.jpgIn North America, coho salmon is a game fish in fresh and salt water from July to December, especially with light fishing tackle. It is one of the most popular sport fish in the Pacific Northwest of the United States and Canada.L. Blair Holtby, Ronald K. Kadowaki, and Kent S. Simpson. 1992. Factors Affecting the Vulnerability of Juvenile Coho (Oncothynchus kisutch) and Chinook Salmon (O. tshawytscha) in a Saltwater Sport Fishery. Canadian Journal of Fisheries and Aquatic Sciences. 49(10): 2164-2178. https://doi.org/10.1139/f92-239 Its popularity is due in part to the reckless abandon which it frequently displays chasing bait and lure while in salt water, and the large number of coastal streams it ascends during its spawning runs. Its habit of schooling in relatively shallow water, and often near beaches, makes it accessible to anglers on the banks, as well as in boats.{{cite web |last1=Sisnyak |first1=Nancy |last2=Ragan |first2=Ryan |title=Fishing for Coho Salmon |url=http://www.adfg.alaska.gov/index.cfm?adfg=wildlifenews.view_article&articles_id=887 |website=Adfg.alaska.gov |publisher=Alaska Department of Fish and Game |access-date=8 December 2020}}

It is also pursued by fly fishermen in salt water.{{cite web |last1=Caputi |first1=Gary |title=Fly Fishing for Silver Salmon |url=https://www.saltwatersportsman.com/story/howto/fly-fishing-for-silver-salmon/ |website=Saltwatersportsman.com|date=28 August 2020 |access-date=8 December 2020}}

Ocean-caught coho is regarded as excellent table fare. It has a moderate to high amount of fat, which is considered to be essential when judging taste. Only spring chinook and sockeye salmon have higher levels of fat in their meat. When smoking coho it is best to use a cold-smoking rather than hot-smoking process, due to their lower fat content compared to sockeye and chinook.

Historically coho, along with other species, has been a staple in the diet of several indigenous peoples, who would also use it to trade with other tribes farther inland.William I Atlas, Natalie C Ban, Jonathan W Moore, Adrian M Tuohy, Spencer Greening, Andrea J Reid, Nicole Morven, Elroy White, William G Housty, Jess A Housty, Christina N Service, Larry Greba, Sam Harrison, Ciara Sharpe, Katherine I R Butts, William M Shepert, Elissa Sweeney-Bergen, Donna Macintyre, Matthew R Sloat, Katrina Connors, Indigenous Systems of Management for Culturally and Ecologically Resilient Pacific Salmon (Oncorhynchus spp.) Fisheries, BioScience, Volume 71, Issue 2, February 2021, Pages 186–204, https://doi.org/10.1093/biosci/biaa144 The coho salmon is also a symbol of several tribes, representing life and sustenance.Carothers, Courtney et al. (2021). Indigenous peoples and salmon stewardship: a critical relationship. 26(1). https://doi.org/10.5751/ES-11972-260116

{{See also|Steelhead and salmon distinct population segments}}

File:Homestead coho salmon Tillamook Forest.jpg, Oregon]]

The U.S. National Marine Fisheries Service (NMFS) has identified seven populations, called Evolutionary Significant Units (ESUs), of coho salmon in Washington, Oregon and California.

{{cite web |url=http://www.nmfs.noaa.gov/pr/glossary.htm#esu |title=Evolutionary Significant Units |year=2005 |publisher=U.S. National Marine Fisheries Service}}{{cite web|url=http://www.nwr.noaa.gov/ESA-Salmon-Listings/Salmon-Populations/Coho/|title=Coho salmon ESUs|access-date=2008-01-28|archive-url=https://web.archive.org/web/20130202014228/http://www.nwr.noaa.gov/ESA-Salmon-Listings/Salmon-Populations/Coho/|archive-date=2013-02-02|url-status=dead}} Four of these ESUs are listed under the U.S. Endangered Species Act (ESA).

{{cite web |url=http://www.nmfs.noaa.gov/pr/laws/esa/ |title=Endangered Species Act|website=Nmfs.noaa.gov|date=9 July 2021}} These are the Lower Columbia River (threatened), Oregon Coast (threatened), Southern Oregon and Northern California Coasts (threatened), and Central California Coast (endangered). The long-term trend for the listed populations is still downward, though there was one recent good year with an increasing trend in 2001.{{cite web |url=http://www.nwr.noaa.gov/Publications/Biological-Status-Reviews/upload/SR2005-allspecies.pdf |title=2005 status review report |access-date=2008-01-28 |archive-url=https://web.archive.org/web/20081002154104/http://www.nwr.noaa.gov/Publications/Biological-Status-Reviews/upload/SR2005-allspecies.pdf |archive-date=2008-10-02 |url-status=dead }}

The Puget Sound/Strait of Georgia ESU in Washington is an NMFS "Species of Concern".

{{cite web |url=http://www.nmfs.noaa.gov/pr/species/concern/ |title=Species of Concern|website=Nmfs.noaa.gov|date=9 July 2021}} Species of Concern are those species for which insufficient information prevents resolving the U.S. National Oceanic and Atmospheric Administration's concerns regarding status and threats and whether to list the species under the ESA.

On May 6, 1997, NMFS, on behalf of the Secretary of Commerce, listed as threatened the Southern Oregon/Northern California Coast coho salmon ESU.62 Fed.Reg. 24588 The coho salmon population in the Southern Oregon/Northern California region has declined from an estimated 150,000–400,000 naturally spawning fish in the 1940s to fewer than 10,000 naturally producing adults today. These reductions are due to natural and man-made changes, including short-term atmospheric trends (such as El Niño, which causes extremes in annual rainfall on the northern California coast), predation by the California sea lion and Pacific harbor seal, and commercial timber harvesting.{{Citation needed|date=October 2008}}

More than 680,000 coho salmon returned to Oregon in 2009, double that of 2007. The Oregon Department of Fish and Wildlife required volunteers to herd fish into hatchery pens. Some creeks were reported to have so many fish, "you could literally walk across on the backs of coho," claimed a Portland television station. Lower temperatures in 2008 North Pacific waters brought in fatter plankton, which, along with greater outflows of Columbia River water, fed the resurgent populations.Galbreath, P. F., Bisbee, M. A., Dompier, D. W., Kamphaus, C. M., & Newsome, T. H. (2014). Extirpation and Tribal Reintroduction of Coho Salmon to the Interior Columbia River Basin. Fisheries, 39(2), 77–87. https://doi.org/10.1080/03632415.2013.874526 The 2009 run was so large, food banks were able to freeze {{convert|40|t}} for later use.

{{cite news

|url=https://www.wsj.com/articles/SB10001424052748703657604575005562712284770

|title=Fish Boom Makes Splash in Oregon

|date=January 21, 2010

|publisher=Wall Street Journal

|access-date=January 21, 2010

| first=Joel

| last=Millman

}}

• Pre-spawn mortality in coho salmon
• Inbreeding in fish

==Footnotes==

{{Reflist|30em}}

• {{ITIS |id=161977 |taxon=Oncorhynchus kisutch |access-date=24 January 2006}}
• {{FishBase|genus=Oncorhynchus|species=kisutch|year=2005|month=10}}
• {{cite web |url=http://www.seagrant.wisc.edu/greatlakesfish/cohosalmon.html |title=Coho salmon in the Great Lakes |access-date=2007-09-14 |archive-url=https://web.archive.org/web/20070923020126/http://www.seagrant.wisc.edu/greatlakesfish/cohosalmon.html |archive-date=2007-09-23 |url-status=dead }}

• [http://library.state.ak.us/asp/edocs/2007/04/ocn131700823.pdf Use of three microhabitats by juvenile coho salmon in Jordan Creek during the winter, 2004-2005 / by Ryan J. Briscoe.] Hosted by the [https://web.archive.org/web/20071012120420/http://library.state.ak.us/asp/ Alaska State Publications Program.]

{{Commons category|Oncorhynchus kisutch}}

{{salmon|state=expanded}}

{{Commercial fish topics}}

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coho salmon

Category:Salmon

Category:Cold water fish

Category:Fish of the Pacific Ocean

Category:Fish of the United States

Category:Freshwater fish of Japan

Category:Western North American coastal fauna

Category:Commercial fish

Category:Game fish

coho salmon

Category:Taxa named by Johann Julius Walbaum