The Coho or Silver Salmon (Oncorhynchus kisutch) has black spots on the back and upper lobe of the caudal fin. The gums are light at the base of the teeth. At sea, these salmon are metallic blue above and silver below. Breeding males have dusky green on the back and head, with bright red sides and a black belly; females have bonze to pink-red sides. Spawning males develop a strongly hooked snout and large teeth. Maximum length is around 100 cm. Chinook Salmon (O. tshawytscha) are very similar in appearance to Coho Salmon while at sea, but Chinook Salmon are larger, have black spots on both the upper and lower caudal fin lobes, and have gums that are dark at the base of the teeth. (Page and Burr 1991)

Coho Salmon occur in northeastern Asia and, in North America, in Arctic and Pacific drainages from Point Hope, Alaska, to Monterey Bay, California (occasionally as far south as Baja California). These fish are anadromous, returning from the ocean to the coastal streams or rivers where they were born to spawn. They reproduce just once, then die. (Page and Burr 1991)

For detailed information on the biology and status of this species, including conservation issues, see this resource from the NOAA Fisheries Office of Protected Resources.

The fish occur in the ocean or in lakes; adults return to the rivers where they were born (Ref. 27547). The young fish emerge in springtime and they usually live in fresh water for 1-2 years (sometimes up to 4 years, Ref. 27547); later they migrate at night to freshwater lakes or to the sea (Ref. 1998). Epipelagic (Ref. 58426). The fish that stay more than two years in fresh water and become sexually ripe without ever going to sea, are called residuals; they never spawn (Ref. 27547). Young fish in lakes and rivers eat mainly insects; they stay almost entirely in deep parts of the river and soon become strongly territorial (Ref. 27547). Upon reaching the sea, the smolts remain close to the coast for a certain time, eating planktonic crustaceans (Ref. 27547). As they grow, they migrate farther out into the sea and hunt larger organisms (Ref. 27547) such as jellyfish, squids and fishes (Ref. 58426). They are hunted by various fishes, birds (mergansers, loons and kingfishers), mammals and lampreys (Ref. 1998). This kind is traded as fresh fish, dried or salted, smoked, canned, preserved and frozen (Ref. 9988). They are steamed, grilled, broiled, cooked in the microwave and baked (Ref. 9988). The Alaska Salmon fishery of this species has been certified by the Marine Stewardship Council (http://www.msc.org/) as well-managed and sustainable (http://www.msc.org/html/content_485.htm).

Baltic sea, British Columbia, Canadian Exclusive Economic Zone [Pacific part], Coastal Waters of Southeast Alaska and British Columbia, European waters (ERMS scope), FAO fishing area 67, Gulf of Maine, North East Pacific, North Pacific, North West Atlantic, North West Territories, Swedish Exclusive Economic Zone, United Kingdom Exclusive Economic Zone

North Pacific: distributed from the Anadyr River in Russia south towards Hokkaido, Japan, and from Point Hope in Alaska southwards to Chamalu Bay in Baja California, Mexico.

Oncorhynchus kisutch, commonly known as coho salmon, are primarily found in coastal waters. Coho salmon do not range widely in the open ocean like that of many other salmon species. Oncorhynchus kisutch are also found in fresh water, during their first year and later while spawning. They are found in fresh streams of the North Pacific, ranging from Baja, California to Alaska (Wheeley, 1985).

Biogeographic Regions: nearctic (Native ); arctic ocean (Native ); atlantic ocean (Native ); pacific ocean (Native )

New Brunswick to Chesapeake Bay

occurs (regularly, as a native taxon) in multiple nations

Canada

Origin: Native

Regularity: Regularly occurring

Currently: Present

Confidence: Confident

Type of Residency: Year-round

United States

Origin: Native

Regularity: Regularly occurring

Currently: Present

Confidence: Confident

Type of Residency: Year-round

Global Range: Native range includes the Pacific Ocean and tributary drainages, in eastern Asia from the Anadyr River south to northern Japan and in North America from Point Hope, Alaska, south to central California and infrequently at sea as far south as Baja California. The species is most abundant between Oregon and southeastern Alaska, rare south of central California. It has been widely stocked in lakes and reservoirs throughout North America and elsewhere.

See Frissell (1993) for a map indicating present and former distribution in the Pacific Northwest and California. See Moyle et al. (1989) for further information on distribution in California.

North Pacific and Eurasia.

Dorsal spines (total): 0; Dorsal soft rays (total): 9 - 13; Analspines: 0; Analsoft rays: 12 - 17; Vertebrae: 61 - 69

Oncorhynchus kisutch typically spend the first year of their life in fresh water. Upon moving to the ocean, growth increases dramatically. At about the third year, coho salmon reach maturity. They weigh from 6 to 12 pounds and can be up to 38 inches in length.

Oncorhynchus kisutch are deep-bodied salmon with unique color characteristics. The dorsal surface is a metallic blue while the sides are a silver color. Black spots appear on the back and upper lobe of the caudal fin. A lateral line is also present. The line is curved toward the front of the fish and straightens out as it approaches the back of the fish. While spawning, the fish's back and belly turn dark. Spawning males' sides develop a bright red line and their jaws become hooked (Clemens and Wilby, 1961).

Range mass: 3 to 6 kg.

Other Physical Features: ectothermic ; heterothermic ; bilateral symmetry

Sexual Dimorphism: sexes colored or patterned differently

Maximum size: 980 mm TL

108 cm TL (male/unsexed; (Ref. 40637)); 65.5 cm (female); max. published weight: 15.2 kg (Ref. 40637); max. reported age: 5 years (Ref. 36794)

Length: 61 cm

Weight: 6000 grams

Characterized by the presence of small black spots on the back and on the upper lobe of the caudal fin, and by the lack of dark pigment along the gum line of the lower jaw (Ref. 27547). The gill rakers are rough and widely spaced; the lateral line is nearly straight (Ref. 27547). The adipose fin is slender; the pelvic fins have an axillary extension (Ref. 27547). Fish in the sea are dark metallic blue or greenish on the back and upper sides, a brilliant silver color on middle and lower sides, and white below; small black spots are present on the back and upper sides and on the upper lobe of the caudal fin (Ref. 27547). During the spawning season fish turn dark to bright green on head and back, bright red on the sides, and often dark on the belly (Ref. 27547). Females are less brightly colored than males (Ref. 27547).

This taxon is one of a number of demersal species in the Amur River system. Demersal river fish are found at the river bottom, feeding on benthos and zooplankton

The persistence of mercury contamination in Amur River bottom sediments is a major issue, arising from historic cinnabar mining in the basin and poor waste management practises, especially in the communist Soviet era, where industrial development was placed ahead of sound conservation practises.

The largest native demersal fish species in the Amur River is the 560 centimeter (cm) long kaluga (Huso dauricus); demersal biota are those that inhabit the bottom of a surface water body. Another large demersal fish found in the Amur is the 300 cm Amur sturgeon (Acipenser schrenckii), a taxon which is endemic to the Amur basin.

Other demersal endemic fish species (all in the concubitae family) of the Amur Basin are Iksookimia longicorpa, I. koreensis, I. hugowolfeldi, Cobitis melanoleuca melanoleuca and the Puan spine loach (Iksookimia pumila).

demersal; anadromous (Ref. 51243); freshwater; brackish; marine; depth range 0 - 250 m (Ref. 50550)

Coho Salmon live in fresh and ocean water. In fresh water, coho like relatively slow moving water with fine gravel. In the ocean, coho tend to live closer to shores than in the open ocean. (StreamNet, 1996)

Aquatic Biomes: rivers and streams; coastal

benthic

anadromous species; born in freshwater, spends most of life at sea, returns upriver to spawn

Depth range based on 34 specimens in 1 taxon.
Water temperature and chemistry ranges based on 1 sample.

Environmental ranges
  Depth range (m): 0.065 - 151
  Temperature range (°C): 7.819 - 7.819
  Nitrate (umol/L): 20.559 - 20.559
  Salinity (PPS): 33.279 - 33.279
  Oxygen (ml/l): 4.214 - 4.214
  Phosphate (umol/l): 1.826 - 1.826
  Silicate (umol/l): 30.305 - 30.305

Graphical representation

Depth range (m): 0.065 - 151
 
Note: this information has not been validated. Check this *note*. Your feedback is most welcome.

Habitat Type: Freshwater

Comments: Coho salmon usually spend 2 (range 1-3) growing seasons in the ocean before spawning. In the ocean, they remain over the continental shelf and generally stay within 30 km of their natal stream (but some may range up to several hundred kilometers away).

Spawning occurs in just about any accessible coastal stream, generally in forested areas, usually at 6-12 C in loose coarse gravel at heads of riffles (or tails of pools) in rounded troughs excavated by females where water is 10-54 cm deep. Females construct and deposit eggs in each of several redds. Individuals generally spawn in their natal stream; however, rapid colonization of newly accessible habitat has been observed.

Young spend a few weeks to 2 years (varies geographically) in freshwater streams before migrating to the sea (young in the north spend a longer time in fresh water than do those in the south). Often this period is substantial and amounts to approximately half of the life cycle. Hatchlings that have left the spawning site seek shallow water, usually along stream margins. Older juveniles prefer pools and runs with good cover, high oxygen levels, and abundant invertebrate populations. Fry may summer in brackish water in southeastern Alaska.

Stocked populations in lakes and reservoirs migrate upstream to spawn or more commonly do not reproduce (must be restocked annually).

Depth: 0 - 250m.
Recorded at 250 meters.

Habitat: demersal.

Anadromous. Fish that ascend rivers to spawn, as salmon and hilsa do. Sub-division of diadromous. Migrations should be cyclical and predictable and cover more than 100 km.

This species has been introduced or released in Dutch waters.

Non-Migrant: No. All populations of this species make significant seasonal migrations.

Locally Migrant: Yes. At least some populations of this species make local extended movements (generally less than 200 km) at particular times of the year (e.g., to breeding or wintering grounds, to hibernation sites).

Locally Migrant: Yes. At least some populations of this species make annual migrations of over 200 km.

Adults migrate up streams typically in late summer and fall (late fall through mid-winter in the far south), when heavy fall rains result in flows strong enough to breach sand bars at the mouths of coastal streams (Moyle et al. 1989).. Some populations, now considered extinct, may have migrated hundreds of miles inland to spawn in tributaries of the upper Columbia River in Washington and the Snake River in Idaho (NMFS 1995).

See NMFS (1995) for information on the oceanic distributions of the different spawning stocks in Washington, Oregon, and California.

In California, "big river coho salmon" begin entering streams typically in September or October, migrate upstream 100-200 km or more to spawning sites; "short-run coho salmon" rarely migrate more than 100 km upstream (Moyle et al. 1989). In California, juveniles begin migration downstream to ocean in early spring; migrate in schools of 10-50 (Moyle et al. 1989).

The fish occur in the ocean or in lakes; adults return to the rivers where they were born (Ref. 27547). The young fish emerge in springtime and they usually live in fresh water for 1-2 years (sometimes up to 4 years, Ref. 27547); later they migrate at night to freshwater lakes or to the sea (Ref. 1998). Epipelagic (Ref. 58426). The fish that stay more than two years in fresh water and become sexually ripe without ever going to sea, are called residuals; they never spawn (Ref. 27547). Young fish in lakes and rivers eat mainly insects; they stay almost entirely in deep parts of the river and soon become strongly territorial (Ref. 27547). Upon reaching the sea, the smolts remain close to the coast for a certain time, eating planktonic crustaceans (Ref. 27547). As they grow, they migrate farther out into the sea and hunt larger organisms (Ref. 27547) such as jellyfish, squids and fishes (Ref. 58426). They are hunted by various fishes, birds (mergansers, loons and kingfishers), mammals and lampreys (Ref. 1998).

In fresh water streams and rivers, juvenile coho salmon defend territories and compete for limited feeding sites with other fish. In order to attain these feeding sites, they may charge or chase other fish away, as growth and fitness depend on it. Coho salmon attack prey by sprinting and striking. They are able to maneuver well in order to capture prey. In fresh water, coho eat insects and smaller fish. When they move to the ocean they begin to grow rapidly due to the abundance of food. Once these fish reach the ocean their diet changes to other fish, such as herring and squid (Groot et. al., 1995).

Comments: Fry feed on a variety of small invertebrates. Parr feed on aquatic insects and their larvae, terrestrial insects, and some small fishes. At sea, preys primarily on other fishes (Moyle 1976), also inverts (see Hassler 1987 for details).

Epitheliocystis. Bacterial diseases

Enteric Redmouth Disease. Bacterial diseases

Note: For many non-migratory species, occurrences are roughly equivalent to populations.

Estimated Number of Occurrences: 81 to >300

Comments: In a survey of populations in the contiguous U.S., Huntington et al. (1996) identified only three healthy native stocks, all in Washington.

10,000 to >1,000,000 individuals

Fry initially form schools, later become territorial after attaining parr stage. Tends to form schools in ocean.

Comments: Feeding activity of juveniles reduced in winter.

Adults migrate from the sea or lake, school at mouths of rivers, and move upstream when rains increase river flow (Ref. 1998). As a rule, the winter entries (December and January) occur in the southern part of the range, with appearance in fresh water becoming progressively earlier to the north (Ref. 30381, 30382, 30383). At the spawning area, the female finds a spot and digs a pitt. At this point she is aggressive toward other females. While digging, an attendant male courts her or is busy driving away other males. As soon as the pitt is completed, the female drops into it and is immediately followed by the male. The pair are side by side, they open their mouth, quiver and release egg and sperm (Ref. 27547). At this point, other males move in and release sperm into the nest (Ref. 1998). The female quickly moves to the upstream edge of the nest and starts digging a new pitt, covering the eggs. The whole process is repeated for several days until the female deposits all her eggs. The male then leaves and may seek another female. The spent female usually continues to dig, until she dies (Ref. 27547).Reproductive strategy: synchronous ovarian organization, determinate fecundity (Ref. 51846).

Average lifespan

Status: wild: 4.1 years.

Average lifespan

Status: wild: 5.0 years.

Average lifespan

Status: wild: 4.0 years.

Maximum longevity: 5 years (wild) Observations: The salmon ages and dies shortly after spawning. It is not considered ageing but rather sudden death.

At three to four years of age, coho salmon reach sexual maturity. From September to October, coho swim to the fresh water streams where they were born (up to 400 miles). Once the fish reach their natal site females dig a nest in a gravel-type area. After the nest is made a female and one male (occasionally 2) breed. In this breeding, the female lays her eggs and the male's sperm is spread over them, thus fertilizing them. After fertilization has occurred, the eggs are buried by other female coho that are digging their nests. Following reproduction, males and females die, giving the waters more nutrients. Larvae hatch 6-8 weeks after fertilization. The larvae remain in the gravel for 2-3 weeks. Coho live in streams or rivers for about a year until they move to the ocean. (Wheeler, 1985)

Average age at sexual or reproductive maturity (male)

Sex: male: 1095 days.

Average age at sexual or reproductive maturity (female)

Sex: female: 1095 days.

Spawning occurs mainly November-January in California, mainly in December in southern Oregon and northern California, most frequently in January south of the Mattole River, and September-December (mainly November-December) in Washington and Oregon

Female may guard nest for up to 2 weeks. Eggs incubate in winter and hatch in 1.5-4 months, depending on temperature. Young emerge from gravel 2-10 weeks after hatching.

Adults die soon after spawning, at age 2-5 years (usually at three years in Washington, Oregon, and California, 4 years in southeastern Alaska); some males return to spawn after only 6 months at sea.

Stocked populations usually do not reproduce.

The following is a representative barcode sequence, the centroid of all available sequences for this species.


There are 163 barcode sequences available from BOLD and GenBank.  Below is a sequence of the barcode region Cytochrome oxidase subunit 1 (COI or COX1) from a member of the species.  See the BOLD taxonomy browser for more complete information about this specimen and other sequences.


Download FASTA File

Barcode of Life Data Systems (BOLDS) Stats
Public Records: 159
Specimens with Barcodes: 175
Species With Barcodes: 1

There has been a serious decline of wild coho stocks in the Strait of Georgia, due to loss of habitat (from dams) and overfishing. A plan of harvest management has been developed and implemented by the Dept. of Fisheries and Oceans. (Pacific Salmon Foundation, 1995)

US Federal List: no special status

CITES: no special status

State of Michigan List: no special status

Canada

Rounded National Status Rank: N4 - Apparently Secure

United States

Rounded National Status Rank: N4 - Apparently Secure

Rounded Global Status Rank: G4 - Apparently Secure

Reasons: Still widespread around the margins of the North Pacific Ocean, and abundant in some areas, but logging and poor watershed management have caused many local extirpations and numerous declines; many runs are reported as now being of less than 25-50 individuals each.

Other Considerations: The wild populations are of primary concern. Each coastal stream probably comprises a distinctive strain adapted for local environments.

Current Listing Status Summary

Status: Endangered
Date Listed: 11/20/1996
Lead Region:   National Marine Fisheries Service (Region 11)   
Where Listed: Central California Coast ESU

Status: Threatened
Date Listed: 06/18/1997
Lead Region:   National Marine Fisheries Service (Region 11)   
Where Listed: Southern Oregon Northern California Coast ESU

Status: Threatened
Date Listed: 06/28/2005
Lead Region:   National Marine Fisheries Service (Region 11)   
Where Listed: Lower Columbia River ESU

Status: Threatened
Date Listed: 04/13/2011
Lead Region:   National Marine Fisheries Service (Region 11)   
Where Listed: Oregon Coast ESU


For most current information and documents related to the conservation status and management of Oncorhynchus kisutch, see its USFWS Species Profile

Global Short Term Trend: Decline of 10-30%

Comments: Of 2594 stocks in British Columbia and Yukon, Slaney et al. (1996) categorized 29 as extirpated, 214 as high risk, 22 as moderate risk, 21 as special concern, 1024 as unthreatened, and 1284 as unknown status. In the 1900s, indigenous, naturally reproducing populations are believed to have been extirpated in nearly all Columbia River tributaries and to be in decline in numerous coastal streams in Washington, Oregon, and California; at least 33 populations have been identified by agencies and conservation groups as being at moderate to high risk of extinction (NMFS 1995); at least 15 stocks in the contiguous U.S. have been extirpated (Nehlsen et al. 1991). Wild fish are increasingly rare throughout the range, especially at the southern and eastern parts of the range (see Nehlsen et al. 1991 for a review of the status and declines of these populations). Stable or increasing in a portion of northern California and in northwestern Washington; special concern, threatened, endangered, or extirpated elsewhere (see map in Frissell 1993). In California, populations fluctuate, but the general trend seems to be downward for wild, short-run populations in small coastal streams.

Not Evaluated

Degree of Threat: B : Moderately threatened throughout its range, communities provide natural resources that when exploited alter the composition and structure of the community over the long-term, but are apparently recoverable

Comments: Many populations have been negatively impacted by logging, agricultural activities, overgrazing, urbanization, stream channelization, wetland loss, and poor watershed management practices that increase stream temperatures, cause siltation, or otherwise destroy or degrade habitat; road construction also has negatively altered many smaller coastal streams; dams, water withdrawals, and unscreened diversions for irrigation also have contributed to the decline. Poor ocean conditions (e.g., El Nino conditions) are believed to have played a prominent role in the decline of populations in Washington, Oregon, and California (NMFS 1995). The effects of extended drought on water supplies and water temperatures are a major concern for California populations of coho salmon. Native populations are most at risk in the southern and eastern parts of the range, largely as a result of the effects of successful hatchery programs (Nehlsen et al. 1991). Potential problems associated with hatchery programs include genetic impacts on indigenous, naturally reproducing populations, disease transmission, predation on wild fishes, difficulty in determination of wild run status due to incomplete marking of hatchery releases, and replacement (rather than supplementation) of wild stocks through competition and continued annual introductions of hatchery fishes (NMFS 1995). It is difficult to assess the degree to which recreational and commercial harvest have contributed to the decline. Spawning fish can withstand moderate disturbance. See NMFS (Federal Register, 6 May 1997) for further information on threats.

Restoration Potential: Recovery will be difficult due to the large number of small coastal streams in which changes in logging and road construction plans would have to be made (Moyle et al. 1989).

Management Requirements: Hatcheries contribute to much of production (Hassler 1987). Meffe (1992) gave reasons why the hatchery approach to recovery ultimately will fail, and he emphasized that overharvest and habitat destruction need to be addressed in a major landscape-level effort. See Thomas et al. (1993) for information on habitat management for this and other at-risk fish species in the Pacific Northwest.

To regulate fishery for optimum yield, California, Washington, and Oregon have limited entry of new fishing boats into fleet and have instituted catch quotas (Hassler 1987).

Stocks transplanted to non-native streams exhibit reduced survival (see Williams et al. 1992).

Allendorf et al. (1997) proposed criteria for prioritizing Pacific salmon stocks for conservation; data limitations introduce subjectivity into the process, so expert judgment and peer review should be incorporated into the process.

Biological Research Needs: Determine genetic variation among wild populations in different streams.

Global Protection: Few to several (1-12) occurrences appropriately protected and managed

Comments: Some spawning streams are protected in state parks and TNC preserves, but adults are harvested on the way up river to spawn.

Needs: Protect spawning and rearing (juvenile) habitats. See Nehlsen et al. (1991) for general protection and management recommendations for anadromous salmonids.

fisheries: highly commercial; aquaculture: commercial; gamefish: yes; price category: medium; price reliability: reliable: based on ex-vessel price for this species

Oncorhynchus kisutch make a good meal. Often, coho are either sold frozen or canned by commercial fisherman. Twice as many coho salmon are harvested commercially in North America than in Asia. During the late 1950's about 10 million coho salmon per year were caught. These numbers declined to 4.5 million coho per year in the 60's and have now risen to about 10.5 million coho per year. Fishing for coho is also an important sport for trollers and flyfisherman. (McNeil et. al, 1980)

Comments: Provides extensive commercial and sport fishery (Hassler 1987). Comprised around 10% of the commercial Pacific salmon catch in the 1970s, with several million caught in North America waters (see Sandercock 1991).

Comments: Apparently does not comprise genetically distinct, temporally segregated runs within a single river drainage, such as those that characterize the chinook salmon and steelhead trout; however, each coastal stream probably has a distinctive strain adapted to local conditions (Moyle et al. 1989). NMFS (1995) determined that there are six major stock groupings in the region extending from southern British Columbia to southern California.

Moyle et al. (1989) divided coho populations in California into two groups: "big river coho salmon" and "short-run coho salmon" (see GMIGRCOM).