The coho salmon (''Oncorhynchus kisutch;''
Karuk
The Karuk people are an indigenous people of California, and the Karuk Tribe is one of the largest tribes in California. Karuks are also enrolled in two other federally recognized tribes, the Cher-Ae Heights Indian Community of the Trinidad Ra ...
: achvuun) is a
species
In biology, a species is the basic unit of Taxonomy (biology), classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of ...
of
anadromous
Fish migration is mass relocation by fish from one area or body of water to another. Many types of fish migrate on a regular basis, on time scales ranging from daily to annually or longer, and over distances ranging from a few metres to thousa ...
fish in the
salmon family and one of the five
Pacific salmon
''Oncorhynchus'' is a genus of fish in the family Salmonidae; it contains the Pacific salmon and Pacific trout. The name of the genus is derived from the Greek ὄγκος (ónkos, “lump, bend”) + ῥύγχος (rhúnkhos, “snout”), in r ...
species. Coho salmon are also known as silver salmon or "silvers". The scientific species name is based on the
Russian
Russian(s) refers to anything related to Russia, including:
*Russians (, ''russkiye''), an ethnic group of the East Slavic peoples, primarily living in Russia and neighboring countries
* Rossiyane (), Russian language term for all citizens and p ...
common name ''kizhuch'' (кижуч).
Description
During their
ocean phase, coho salmon have silver sides and dark-blue backs. During their spawning phase, their
jaw
The jaw is any opposable articulated structure at the entrance of the mouth, typically used for grasping and manipulating food. The term ''jaws'' is also broadly applied to the whole of the structures constituting the vault of the mouth and serv ...
s and
teeth
A tooth ( : teeth) is a hard, calcified structure found in the jaws (or mouths) of many vertebrates and used to break down food. Some animals, particularly carnivores and omnivores, also use teeth to help with capturing or wounding prey, tea ...
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 average and , occasionally reaching up to . They also develop a large
kype
A kype is a hook-like secondary sex characteristic which develops at the distal tip of the lower jaw in some male salmonids prior to the spawning season. The structure usually develops in the weeks prior to, and during, migration to the spawning g ...
(hooked beak) during spawning. Mature females may be darker than males, with both showing a pronounced hook on the nose.
Reproduction
The eggs hatch in the late winter or early spring after six to seven weeks in the
redd
Redd is a Turkish rock band established in 1996 by tenor opera singer Doğan Duru and guitarist Berke Hatipoğlu under the name ''Ten''. They used to play at bars until they set up their own studio in 2004. Their first album, titled ''"50/50" ...
. Once hatched, they remain mostly immobile in the redd during the
alevin
Fish go through various life stages between fertilization and adulthood. The life of a fish start as spawned eggs which hatch into immotile larvae. These larval hatchlings are not yet capable of feeding themselves and carry a yolk sac whic ...
life stage, which lasts for 6–7 weeks. Alevin no longer have the protective egg shell, or
chorion
The chorion is the outermost fetal membrane around the embryo in mammals, birds and reptiles (amniotes). It develops from an outer fold on the surface of the yolk sac, which lies outside the zona pellucida (in mammals), known as the vitelline me ...
, 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. 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 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
Brackish water, sometimes termed brack water, is water occurring in a natural environment that has more salinity than freshwater, but not as much as seawater. It may result from mixing seawater (salt water) and fresh water together, as in estuar ...
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
Spawn or spawning may refer to:
* Spawn (biology), the eggs and sperm of aquatic animals
Arts, entertainment, and media
* Spawn (character), a fictional character in the comic series of the same name and in the associated franchise
** '' Spawn: A ...
. Some precocious males, known as "jacks", return as two-year-old spawners. Spawning males develop kypes, which are strongly hooked
snout
A snout is the protruding portion of an animal's face, consisting of its nose, mouth, and jaw. In many animals, the structure is called a muzzle, rostrum, or proboscis. The wet furless surface around the nostrils of the nose of many mammals is c ...
s and large
teeth
A tooth ( : teeth) is a hard, calcified structure found in the jaws (or mouths) of many vertebrates and used to break down food. Some animals, particularly carnivores and omnivores, also use teeth to help with capturing or wounding prey, tea ...
.
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 Breeding Male.jpg, Breeding male
Range
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
The Bering Sea (, ; rus, Бе́рингово мо́ре, r=Béringovo móre) is a marginal sea of the Northern Pacific Ocean. It forms, along with the Bering Strait, the divide between the two largest landmasses on Earth: Eurasia and The Ame ...
to mainland
Alaska
Alaska ( ; russian: Аляска, Alyaska; ale, Alax̂sxax̂; ; ems, Alas'kaaq; Yup'ik: ''Alaskaq''; tli, Anáaski) is a state located in the Western United States on the northwest extremity of North America. A semi-exclave of the U.S., ...
, and south to
Monterey Bay, California. Coho salmon have also been introduced in all the
Great Lakes, as well as many landlocked reservoirs throughout the
United States. A number of specimens, (more than 20), 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.
Human uses
Fisheries
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.
[ 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; however, the majority are caught by the net fishery (
gillnet
Gillnetting is a fishing method that uses gillnets: vertical panels of netting that hang from a line with regularly spaced floaters that hold the line on the surface of the water. The floats are sometimes called "corks" and the line with corks is ...
and
seine). Coho salmon average 3.5% by fish and 5.9% by weight of the annual Alaska salmon harvest. The total North Pacific yields of the
pink salmon
Pink salmon or humpback salmon (''Oncorhynchus gorbuscha'') is a species of anadromous fish in the salmon family. It is the smallest and most abundant of the Pacific salmon. The scientific species name is based on the Russian common name for ...
,
chum salmon
The chum salmon (''Oncorhynchus keta''), also known as dog salmon or keta salmon, is a species of anadromous salmonid fish from the genus ''Oncorhynchus'' (Pacific salmon) native to the coastal rivers of the North Pacific and the Beringian Arcti ...
and
sockeye salmon are some 10–20 fold larger by weight.
[
]
Game fish
In 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. Its popularity is due in part to the reckless abandon which it frequently displays chasing bait and lure while in salt water
Saline water (more commonly known as salt water) is water that contains a high concentration of dissolved salts (mainly sodium chloride). On the United States Geological Survey (USGS) salinity scale, saline water is saltier than brackish w ...
, 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.
It is also pursued by fly fisherman in salt water.
Nutritional value
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.
Cultural tradition
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. The coho salmon is also a symbol of several tribes, representing life and sustenance.
Ecology
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. 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. Adult coho feed on a vast variety of prey items that depend on the region they reside in during their second year at sea. Spawning habitats are small streams with stable gravel substrates.
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.
Conservation
The U.S. National Marine Fisheries Service
The National Marine Fisheries Service (NMFS), informally known as NOAA Fisheries, is a United States federal agency within the U.S. Department of Commerce's National Oceanic and Atmospheric Administration (NOAA) that is responsible for the stew ...
(NMFS) has identified seven populations, called Evolutionary Significant Units (ESUs), of coho salmon in Washington
Washington commonly refers to:
* Washington (state), United States
* Washington, D.C., the capital of the United States
** A metonym for the federal government of the United States
** Washington metropolitan area, the metropolitan area centered o ...
, Oregon and California. Four of these ESUs are listed under the U.S. Endangered Species Act (ESA). These are the Lower Columbia River
The Columbia River ( Upper Chinook: ' or '; Sahaptin: ''Nch’i-Wàna'' or ''Nchi wana''; Sinixt dialect'' '') is the largest river in the Pacific Northwest region of North America. The river rises in the Rocky Mountains of British Columbia, ...
(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.
The Puget Sound/ Strait of Georgia ESU in Washington is an NMFS "Species of Concern". 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
The United States secretary of commerce (SecCom) is the head of the United States Department of Commerce. The secretary serves as the principal advisor to the president of the United States on all matters relating to commerce. The secretary rep ...
, listed as threatened the Southern Oregon/Northern California Coast coho salmon ESU. 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
The California sea lion (''Zalophus californianus'') is a coastal eared seal native to western North America. It is one of six species of sea lions. Its natural habitat ranges from southeast Alaska to central Mexico, including the Gulf of Califo ...
and Pacific harbor seal
The harbor (or harbour) seal (''Phoca vitulina''), also known as the common seal, is a true seal found along temperate and Arctic marine coastlines of the Northern Hemisphere. The most widely distributed species of pinniped (walruses, eared se ...
, and commercial timber harvesting.
More than 680,000 coho salmon returned to Oregon in 2009, double that of 2007. The Oregon Department of Fish and Wildlife
The Oregon Department of Fish and Wildlife (ODFW) is a government agency of the U.S. state of Oregon responsible for programs protecting Oregon fish and wildlife resources and their habitats.
The agency operates hatcheries, issues hunting and ...
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
The Columbia River ( Upper Chinook: ' or '; Sahaptin: ''Nch’i-Wàna'' or ''Nchi wana''; Sinixt dialect'' '') is the largest river in the Pacific Northwest region of North America. The river rises in the Rocky Mountains of British Columbia, ...
water, fed the resurgent populations. The 2009 run was so large, food banks were able to freeze for later use.[
]
See also
* Pre-spawn mortality in coho salmon
Footnotes
References
*
*
*
Technical reports
Use of three microhabitats by juvenile coho salmon in Jordan Creek during the winter, 2004-2005 / by Ryan J. Briscoe.
Hosted by th
Alaska State Publications Program.
External links
{{Authority control
coho salmon
The coho salmon (''Oncorhynchus kisutch;'' Karuk: achvuun) is a species of anadromous fish in the salmon family (biology), family and one of the five Pacific salmon species. Coho salmon are also known as silver salmon or "silvers". The scientif ...
Salmon
Cold water fish
Fish of the Pacific Ocean
Fish of the United States
Freshwater fish of Japan
Western North American coastal fauna
Commercial fish
Sport fish
coho salmon
The coho salmon (''Oncorhynchus kisutch;'' Karuk: achvuun) is a species of anadromous fish in the salmon family (biology), family and one of the five Pacific salmon species. Coho salmon are also known as silver salmon or "silvers". The scientif ...
Taxa named by Johann Julius Walbaum