Product Code Database
Salmon (; : salmon) are any of several commercially important species of euryhaline ray-finned fish from the genera Salmo and Oncorhynchus of the family Salmonidae, native to tributary of the North Atlantic ( Salmo) and North Pacific ( Oncorhynchus) basins. Salmon is a colloquial or common name used for fish in this group, but is not a scientific name. Other closely related fish in the same family include trout, Salvelinus, Thymallus, whitefish, lenok and Hucho, all coldwater fish of the subarctic and cooler temperate regions with some sporadic endorheic populations in Central Asia.
Salmon are typically fish migration: they hatch in the shallow gravel stream bed of freshwater and spend their juvenile fish years in , and freshwater , migrate to the ocean as and live like sea fish, then natal homing to reproduce. However, populations of several species are restricted to fresh waters (i.e. landlocked) throughout their lives. Folklore has it that the fish return to the exact stream where they themselves hatched to spawn, and tracking studies have shown this to be mostly true. A portion of a returning salmon run may stray and spawn in different freshwater systems; the percent of straying depends on the species of salmon. Homing behavior has been shown to depend on olfactory memory.
Salmon are important food fish and are intensively farmed in many parts of the world, (2025). 9781888569780, American Fisheries Society. ISBN 9781888569780 with Norway being the world's largest producer of farmed salmon, followed by Chile. They are also highly prized game fish for recreational fishing, by both freshwater and saltwater angling. Many species of salmon have since been introduced and naturalized into non-native environments such as the Great Lakes of North America, Patagonia in South America and South Island of New Zealand.McDowall, R. M. (1994). The origins of New Zealand's chinook salmon, Oncorhynchus tshawytscha. Marine Fisheries Review, 1 January 1994.
| Chum salmon | Oncorhynchus keta (Walbaum, 1792) | 7 years | 3.5 | Least concern Accessed on 25 May 2025. | |||||||
| Coho salmon | Oncorhynchus kisutch (Walbaum, 1792) | 5 years | 4.2 | Least concern Accessed on 25 May 2025 | |||||||
| Masu salmon | Oncorhynchus masou (Brevoort, 1856) | 3 years | 3.6 | Not assessed | |||||||
| Pink salmon | Oncorhynchus gorbuscha (Walbaum, 1792) | 3 years | 4.2 | Least concern Accessed on 25 May 2025 | |||||||
| Sockeye salmon | Oncorhynchus nerka (Walbaum, 1792) | 8 years | 3.7 | Least concern |
The extinct Eosalmo driftwoodensis, the oldest known Salmoninae fish in the fossil record, helps scientists figure how the different species of salmon diverged from a common ancestor. The Eocene salmon's fossil from British Columbia provides evidence that the divergence between Pacific and Atlantic salmon had not yet occurred 40 million years ago. Both the fossil record and analysis of mitochondrial DNA suggest the divergence occurred 10 to 20 million years ago during the Miocene. This independent evidence from DNA analysis and the fossil record indicate that salmon divergence occurred long before the Quaternary glaciation began the cycle of glacial advance and retreat.
| Australian salmon | Arripis trutta (Forster, 1801) | Perciformes | 26 years | 4.1 | Not assessed | ||||||
| Danube salmon | Hucho hucho (Linnaeus, 1758) | Salmoniformes | 15 years | 4.2 | Endangered | ||||||
| Hawaiian salmon | Elagatis bipinnulata (Quoy & Gaimard, 1825) | Carangiformes | 6 years | 3.6 | Not assessed | ||||||
| Indian salmon | Eleutheronema tetradactylum (Shaw, 1804) | Perciformes | years | 4.4 | Not assessed |
The smolt body chemistry changes, allowing them to live in salt water. While a few species of salmon remain in fresh water throughout their life cycle, the majority are Fish migration and migrate to the ocean for maturation: in these species, smolts spend a portion of their out-migration time in brackish water, where their body chemistry becomes accustomed to osmoregulation in the ocean. This body chemistry change is hormone-driven, causing physiological adjustments in the function of osmoregulatory organs such as the gills, which leads to large increases in their ability to secrete salt. Hormones involved in increasing salinity tolerance include insulin-like growth factor I, cortisol, and thyroid hormones, which permits the fish to endure the transition from a freshwater environment to the ocean.
The salmon spend about one to five years (depending on the species) in the open ocean, where they gradually become sexually mature. The adult salmon then return primarily to their natal streams to spawn. Atlantic salmon spend between one and four years at sea. When a fish returns after just one year's sea feeding, it is called a grilse in Canada, Britain, and Ireland. Grilse may be present at spawning, and go unnoticed by large males, releasing their own sperm on the eggs. (2025). 9781466598485, CRC Press. ISBN 9781466598485
Prior to spawning, depending on the species, salmon undergo changes. They may grow a hump, develop canine-like teeth, or develop a kype (a pronounced curvature of the jaws in male salmon). All change from the silvery blue of a fresh-run fish from the sea to a darker colour. Salmon can make amazing journeys, sometimes moving hundreds of miles upstream against strong currents and rapids to reproduce. Chinook and sockeye salmon from central Idaho, for example, travel over and climb nearly from the Pacific Ocean as they return to spawn. Condition tends to deteriorate the longer the fish remain in fresh water, and they then deteriorate further after they spawn, when they are known as kelts. In all species of Pacific salmon, the mature individuals die within a few days or weeks of spawning, a trait known as semelparity. Between 2 and 4% of Atlantic salmon kelts survive to spawn again, all females. However, even in those species of salmon that may survive to spawn more than once (iteroparity), postspawning mortality is quite high (perhaps as high as 40 to 50%).
To lay her roe, the female salmon uses her tail (caudal fin), to create a low-pressure zone, lifting gravel to be swept downstream, excavating a shallow depression, called a redd. The redd may sometimes contain 5,000 eggs covering . The eggs usually range from orange to red. One or more males approach the female in her redd, depositing sperm, or milt, over the roe. The female then covers the eggs by disturbing the gravel at the upstream edge of the depression before moving on to make another redd. The female may make as many as seven redds before her supply of eggs is exhausted.
Each year, the fish experiences a period of rapid growth, often in summer, and one of slower growth, normally in winter. This results in ring formation around an earbone called the otolith (annuli), analogous to the growth rings visible in a tree trunk. Freshwater growth shows as densely crowded rings, sea growth as widely spaced rings; spawning is marked by significant erosion as body mass is converted into eggs and milt.
Freshwater streams and estuary provide important habitat for many salmon species. They feed on insects and aquatic insects, amphipods, and other crustaceans while young, and primarily on other fish when older. Eggs are laid in deeper water with larger gravel and need cool water and good water flow (to supply oxygen) to the developing embryos. Mortality of salmon in the early life stages is usually high due to natural predation and human-induced changes in habitat, such as siltation, high water temperatures, low oxygen concentration, loss of stream cover, and reductions in river flow. Estuaries and their associated wetlands provide vital nursery areas for the salmon prior to their departure to the open ocean. Wetlands not only help buffer the estuary from silt and pollutants, but also provide important feeding and hiding areas.
Salmon not killed by other means show greatly accelerated deterioration (phenoptosis, or "programmed aging") at the end of their lives. Their bodies rapidly deteriorate right after they spawn as a result of the release of massive amounts of .
As adults, salmon behave like other mid-sized pelagic fish, eating a variety of sea creatures including smaller forage fish such as lanternfish, , , and barracudina. They also eat krill, squid and Polychaete.
In the case of Pacific salmon, most (if not all) of the salmon that survive to reach the headwater spawning grounds will semelparity and their dead bodies sink to cover the gravel beds, with the nutrients released from the biodegradation of their corpses providing a significant boost to these otherwise biomass-poor shallow streams.
An example of this was seen in the years following 1818 in the Columbia River Basin. In 1818, the British government made an agreement with the U.S. government to allow U.S. citizens access to the Columbia catchment (see Treaty of 1818). At the time, the Hudson's Bay Company sent word to fur trapping to extirpate all furbearers from the area in an effort to make the area less attractive to U.S. fur traders. In response to the elimination of beavers from large parts of the river system, plummeted, even in the absence of many of the factors usually associated with the demise of salmon runs. Salmon recruitment can be affected by beavers' dams because dams can:
Beaver dams are able to nurture salmon juveniles in estuarine where the salinity is less than 10 ppm. Beavers build small dams of generally less than high in channels in the myrtle zone. These dams can be overtopped at high tide and hold water at low tide. This provides refuges for juvenile salmon so they do not have to swim into large channels where they are subject to predation by larger fish.
Henneguya and other parasites in the myxosporean group have complex life cycles, where the salmon is one of two hosts. The fish releases the spores after spawning. In the Henneguya case, the spores enter a second host, most likely an invertebrate, in the spawning stream. When juvenile salmon migrate to the Pacific Ocean, the second host releases a stage infective to salmon. The parasite is then carried in the salmon until the next spawning cycle. The myxosporean parasite that causes whirling disease in trout has a similar life cycle. However, as opposed to whirling disease, the Henneguya infestation does not appear to cause disease in the host salmon—even heavily infected fish tend to return to spawn successfully.
According to Dr. Kieser, a lot of work on Henneguya salminicola was done by scientists at the Pacific Biological Station in Nanaimo in the mid-1980s, in particular, an overview report which states, "the fish that have the longest fresh water residence time as juveniles have the most noticeable infections. Hence in order of prevalence, coho are most infected followed by sockeye, chinook, chum and pink. As well, the report says, at the time the studies were conducted, stocks from the middle and upper reaches of large river systems in British Columbia such as Fraser River, Skeena River, Nass River and from mainland coastal streams in the southern half of B.C., "are more likely to have a low prevalence of infection." The report also states, "It should be stressed that Henneguya, economically deleterious though it is, is harmless from the view of public health. It is strictly a fish parasite that cannot live in or affect warm blooded animals, including man".
According to Klaus Schallie, Molluscan Shellfish Program Specialist with the Canadian Food Inspection Agency, " Henneguya salminicola is found in southern B.C. also and in all species of salmon. I have previously examined smoked chum salmon sides that were riddled with cysts and some sockeye runs in Barkley Sound (southern B.C., west coast of Vancouver Island) are noted for their high incidence of infestation."
Sea lice, particularly Lepeophtheirus salmonis and various Caligus species, including C. clemensi and C. rogercresseyi, can cause deadly infestations of both farm-grown and wild salmon. Sea lice are which feed on mucus, blood, and skin, and migrate and latch onto the skin of wild salmon during free-swimming, planktonic nauplii and copepodid larval stages, which can persist for several days.
Large numbers of highly populated, open-net salmon farms can create exceptionally large concentrations of sea lice; when exposed in river estuaries containing large numbers of open-net farms, many young wild salmon are infected, and do not survive as a result. Adult salmon may survive otherwise critical numbers of sea lice, but small, thin-skinned juvenile salmon migrating to sea are highly vulnerable. On the Pacific coast of Canada, the louse-induced mortality of pink salmon in some regions is commonly over 80%.
Nearly all captured wild salmon are Pacific salmon. The capture of wild Atlantic salmon has always been relatively small, and has declined steadily since 1990. In 2011 only 2,500 tonnes were reported. In contrast, about half of all farmed salmon are Atlantic salmon.
Salmon are carnivorous, and need to be fed meals produced from catching other wild forage fish and other marine organisms. Salmon farming leads to a high demand for wild forage fish. As a predator, salmon require large nutritional intakes of protein, and farmed salmon consume more fish than they generate as a final product. On a dry weight basis, 2–4 kg of wild-caught fish are needed to produce one kilogram of salmon. As the salmon farming industry expands, it requires more forage fish for feed, at a time when 75% of the world's monitored fisheries are already near to or have exceeded their maximum sustainable yield. The industrial-scale extraction of wild forage fish for salmon farming affects the survivability of other wild predatory fish which rely on them for food. Research is ongoing into sustainable and plant-based salmon feeds.
Intensive salmon farming uses open-net cages, which have low production costs. It has the drawback of allowing disease and sea lice to spread to local wild salmon stocks.
Another form of salmon production, which is safer but less controllable, is to raise salmon in hatchery until they are old enough to become independent. They are released into rivers in an attempt to increase the salmon population. This system is referred to as ranching. It was very common in countries such as Sweden, before the Norwegians developed salmon farming, but is seldom done by private companies. As anyone may catch the salmon when they return to spawn, a company is limited in benefiting financially from their investment.
Because of this, the ranching method has mainly been used by various public authorities and non-profit groups, such as the Cook Inlet Aquaculture Association, as a way to increase salmon populations in situations where they have declined due to , construction of and habitat destruction or fragmentation. Negative consequences to this sort of population manipulation include genetic "dilution" of the wild stocks. Many jurisdictions are now beginning to discourage supplemental fish planting in favour of harvest controls, and habitat improvement and protection.
A variant method of fish stocking, called ocean ranching, is under development in Alaska. There, the young salmon are released into the ocean far from any wild salmon streams. When it is time for them to spawn, they return to where they were released, where fishermen can catch them.
An alternative method to hatcheries is to use spawning channels. These are canal, usually parallel to an existing stream, with concrete or rip-rap sides and gravel bottoms. Water from the adjacent stream is piped into the top of the channel, sometimes via a header pond, to settle out sediment. Spawning success is often much better in channels than in adjacent streams due to the control of floods, which in some years can wash out the natural redds. Because of the lack of floods, spawning channels must sometimes be cleaned out to remove accumulated sediment. The same floods that destroy natural redds also clean the regular streams. Spawning channels preserve the natural selection of natural streams, as there is no benefit, as in hatcheries, to use prophylactic chemicals to control diseases.
Farm-raised salmon are fed the carotenoids astaxanthin and canthaxanthin to match their flesh colour to wild salmon to improve their marketability. Wild salmon get these , primarily astaxanthin, from eating shellfish and krill.
One proposed alternative to the use of wild-caught fish as feed for the salmon, is the use of soy-based products. This should be better for the local environment of the fish farm, but producing soy beans has a high environmental cost for the producing region. The fish omega-3 fatty acid content would be reduced compared to fish-fed salmon.
Another possible alternative is a yeast-based coproduct of bioethanol production, fermentation biomass. Substituting such products for engineered feed can result in equal (sometimes enhanced) growth in fish. With its increasing availability, this would address the problems of rising costs for buying hatchery fish feed.
Yet another attractive alternative is the increased use of seaweed. Seaweed provides essential minerals and vitamins for growing organisms. It offers the advantage of providing natural amounts of dietary fiber and having a lower glycemic load than grain-based fish meal. In the best-case scenario, widespread use of seaweed could yield a future in aquaculture that eliminates the need for land, freshwater, or fertilizer to raise fish. Salmon Recovery Planning. nwr.noaa.gov. p. 57.
Alaska fishery stocks are still abundant, and catches have been on the rise in recent decades, after the state initiated limitations in 1972. Some of the most important Alaskan salmon sustainable wild fisheries are located near the Kenai River, Copper River, and in Bristol Bay. Fish farming of Pacific salmon is outlawed in the United States Exclusive Economic Zone, however, there is a substantial network of publicly funded hatchery, media.aprn.org |low fish returns in Southeast this summer have been tough on the region's hatcheries and the State of Alaska's fisheries management system is viewed as a leader in the management of wild Fish stocks.
In Canada, returning Skeena River wild salmon support commercial, Artisan fishing and recreational fisheries, as well as the area's diverse wildlife on the coast and around communities hundreds of miles inland in the watershed. The status of wild salmon in Washington is mixed. Of 435 wild stocks of salmon and steelhead, only 187 of them were classified as healthy; 113 had an unknown status, one was extinct, 12 were in critical condition and 122 were experiencing depressed populations.
The commercial salmon fisheries in California have been either severely curtailed or closed completely in recent years, due to critically low returns on the Klamath and or Sacramento rivers, causing millions of dollars in losses to commercial fishermen. Both Atlantic and Pacific salmon are popular sportfish.
Salmon populations have been established in all the Great Lakes. Coho stocks were planted by the state of Michigan in the late 1960s to control the growing population of non-native alewife. Now Chinook (king), Atlantic, and coho (silver) salmon are annually stocked in all Great Lakes by most bordering states and provinces. These populations are not self-sustaining and do not provide much in the way of a commercial fishery, but have led to the development of a thriving sport fishery.
Wild, self sustaining Pacific salmon populations have been established in New Zealand, Chile, and Argentina. They are highly prized by sport fishers, but others worry about displacing native fish species. Also, and especially in Chile (Aquaculture in Chile), both Atlantic and Pacific salmon are used in net pen farming.
In 2020 researchers reported widespread declines in the sizes of four species of wild Pacific salmon: Chinook, chum, coho, and sockeye. These declines have been occurring for 30 years, and are thought to be associated with climate change and competition with growing numbers of pink and hatchery salmon. Text and images are available under a Creative Commons Attribution 4.0 International License.
Salmon flesh is generally orange to red, although white-fleshed wild salmon with white-black skin colour occurs. The natural colour of salmon results from carotenoid pigments, largely astaxanthin, but also canthaxanthin, in the flesh. Wild salmon get these carotenoids from eating krill and other tiny shellfish.
The vast majority of Atlantic salmon available in market around the world are farmed (almost 99%), whereas the majority of Oncorhynchus are wild-caught (greater than 80%). Canned salmon in the U.S. is usually wild Pacific catch, though some farmed salmon is available in canned form. Smoked salmon is another popular preparation method, and can either be hot or cold smoked. Lox can refer to either cold-smoked salmon or salmon cured in a brine solution (also called gravlax). Traditional canned salmon includes some skin (which is harmless) and bone (which adds calcium). Skinless and boneless canned salmon is also available.
Raw salmon flesh may contain Anisakis , marine that cause anisakiasis. Before the availability of refrigeration, the did not consume raw salmon. Salmon and salmon roe have only recently come into use in making sashimi (raw fish) and sushi.
To the Indigenous peoples of the Pacific Northwest Coast, salmon is considered a vital part of the diet. Specifically, the indigenous peoples of Haida Gwaii, located near former Queen Charlotte Island in British Columbia, rely on salmon as one of their main sources of food, although many other bands have fished Pacific waters for centuries. Salmon are not only ancient and unique, but it is important because it is expressed in culture, art forms, and ceremonial feasts. Annually, salmon spawn in Haida, feeding on everything on the way upstream and down. Within the Haida nation, salmon is referred to as "tsiin", and is prepared in several ways including smoking, baking, frying, and making soup.
Historically, there has always been enough salmon, as traditional subsistence fishing methods did not result in overfishing, and people only took what they needed. In 2003, a report on First Nations participation in commercial fisheries, including salmon, commissioned by BC's Ministry of Agriculture and Food found that there were 595 First Nation-owned and operated commercial vessels in the province. Of those vessels, First Nations' members owned 564. However, employment within the industry has decreased overall by 50% in the last decade, with 8,142 registered commercial fishermen in 2003. This has affected employment for many fisherman, who rely on salmon as a source of income.
Black bears also rely on salmon as food. The leftovers the bears leave behind are considered important nutrients for the Canadian forest, such as the soil, trees and plants. In this sense, the salmon feed the forest and in return receive clean water and gravel in which to hatch and grow, sheltered from extremes of temperature and water flow in times of high and low rainfall. However, the condition of the salmon in Haida has been affected in recent decades. Due to logging and development, much of the salmon's habitat (i.e., Ain River) has been destroyed, resulting in the fish being close to endangered. For residents, this has resulted in limits on catches, in turn, has affected families diets, and cultural events such as feasts. Some of the salmon systems in danger include: the Davidon, Naden, Mamim, and Mathers.
Many tribes, such as the Yurok, had a taboo against harvesting the first fish that swam upriver in summer, but once they confirmed that the salmon run had returned in abundance they would begin to catch them in plentiful. The indigenous practices were guided by deep ecological wisdom, which was eradicated when Euro-American settlements began to be developed. Salmon have a much grander history than what is presently shown today. The salmon that once dominated the Pacific Ocean are now just a fraction in population and size. The Pacific salmon population is now less than 1–3% of what it was when Lewis and Clark arrived at the region. In his 1908 State of the Union address, U.S. President Theodore Roosevelt observed that the fisheries were in significant decline:
The salmon fisheries of the Columbia River are now but a fraction of what they were twenty-five years ago, and what they would be now if the United States Government had taken complete charge of them by intervening between Oregon and Washington. During these twenty-five years the fishermen of each State have naturally tried to take all they could get, and the two legislatures have never been able to agree on joint action of any kind adequate in degree for the protection of the fisheries. At the moment the fishing on the Oregon side is practically closed, while there is no limit on the Washington side of any kind, and no one can tell what the courts will decide as to the very statutes under which this action and non-action result. Meanwhile very few salmon reach the spawning grounds, and probably four years hence the fisheries will amount to nothing; and this comes from a struggle between the associated, or gill-net, fishermen on the one hand, and the owners of the fishing wheels up the river.
On the Columbia River, the Chief Joseph Dam completed in 1955 completely blocks salmon migration to the upper Columbia River system.
The Fraser River salmon population was affected by the 1914 slide caused by the Canadian Pacific Railway at Hells Gate. The 1917 catch was one quarter of the 1913 catch.
The salmon argument was one of the arguments about the location of the origin of the Indo-European languages.
Salmon also feature in Welsh mythology. In the prose tale Culhwch and Olwen, the Salmon of Llyn Llyw is the oldest animal in Britain, and the only creature who knows the location of Mabon ap Modron. After speaking to a string of other ancient animals who do not know his whereabouts, King Arthur's men Sir Kay and Bedivere are led to the Salmon of Llyn Llyw, who lets them ride its back to the walls of Mabon's prison in Gloucester.
In Norse mythology, after Loki tricked the blind god Höðr into killing his brother Baldr, Loki jumped into a river and transformed himself into a salmon to escape punishment from the other gods. When they held out a net to trap him he attempted to leap over it but was caught by Thor who grabbed him by the tail with his hand, and this is why the salmon's tail is tapered.
Salmon are central spiritually and culturally to Native American mythology on the Pacific coast, from the Haida people and Coast Salish peoples, to the Nuu-chah-nulth peoples in British Columbia.
|
|
