Salmon

occupied:

Some other fishes called salmon
Common name	Scientific name	Order	Maximum length	Common length	Maximum weight	Maximum age	Trophic level	Fish Base	FAO	ITIS	IUCN status
Australian salmon	Arripis trutta (Forster, 1801)	Perciformes	89 cm (2 ft 11 in)	47 cm (1 ft 7 in)	9.4 kilograms (21 lb)	26 years	4.1	[34]		[35]	Not assessed
Danube salmon	Hucho hucho (Linnaeus, 1758)	Salmoniformes	150 cm (4 ft 11 in)	70 cm (2 ft 4 in)	52 kilograms (115 lb)	15 years	4.2	[36]		[37]	Endangered[38]
Hawaiian salmon	Elagatis bipinnulata (Quoy & Gaimard, 1825)	Carangiformes	180 cm (5 ft 11 in)	90 cm (2 ft 11 in)	46.2 kilograms (102 lb)	6 years	3.6	[39]	[40]	[41]	Not assessed
Indian salmon	Eleutheronema tetradactylum (Shaw, 1804)	Perciformes	200 cm (6 ft 7 in)	50 cm (1 ft 8 in)	145 kilograms (320 lb)	years	4.4	[42]		[43]	Not assessed

Distribution

Pacific salmon leaping at Willamette Falls, Oregon

Commercial production of salmon in million tonnes 1950–2010^[44]

• Atlantic salmon (Salmo salar) reproduce in northern rivers on both coasts of the Atlantic Ocean.
  • Landlocked Atlantic salmon (Salmo salar m. sebago) is a
    morph that live in a number of lakes in eastern North America and in Northern Europe, for instance in lakes Sebago, Onega, Ladoga, Saimaa, Vänern and Winnipesaukee
    . They are not a different species from the sea-run Atlantic salmon but have independently evolved a freshwater-only life cycle, which they maintain even when they could access the ocean.
• king salmon or "blackmouth salmon", and as "spring salmon" in British Columbia, Canada. Chinook salmon is the largest of all Pacific salmon, frequently exceeding 6 ft (1.8 m) and 14 kg (30 lb).^[45] The name tyee is also used in British Columbia to refer to Chinook salmon over 30 pounds and in the Columbia River watershed, especially large Chinooks were once referred to as June hogs. Chinook salmon are known to range as far north as the Mackenzie River and Kugluktuk in the central Canadian arctic,^[46] and as far south as the Central Californian Coast.^[47]
• Kyūshū in the Sea of Japan
  .
• silver salmon. This species is found throughout the coastal waters of Alaska and British Columbia and as far south as Central California (Monterey Bay).^[49] It is also now known to occur, albeit infrequently, in the Mackenzie River.^[46]
• Masu salmon (Oncorhynchus masou), also known as "cherry trout" (桜鱒 サクラマス, sakura masu) in Japan, are found only in the western Pacific Ocean in Japan, Korea, and Russian Far East. A landlocked subspecies known as the Taiwanese salmon or Formosan salmon (Oncorhynchus masou formosanus) is found in central Taiwan's Chi Chia Wan Stream.^[50]
• Pink salmon (Oncorhynchus gorbuscha), known as humpback salmon or "humpies" in southeast and southwest Alaska, are found in the western Pacific from Lena River in Siberia to Korea, found throughout northern Pacific, and in the eastern Pacific from the Mackenzie River in Canada^[46] to northern California, usually in shorter coastal streams. It is the smallest of the Pacific species, with an average weight of 1.6 to 1.8 kg (3.5 to 4.0 lb).^[51]
• Hokkaidō island in Japan. Although most adult Pacific salmon feed on small fish, shrimp, and squid, sockeye feed on plankton they filter through gill rakers.^[53] Kokanee salmon
  are the landlocked form of sockeye salmon.
• Danube salmon, or huchen (Hucho hucho), are the largest permanent freshwater salmonid species.

Life cycle

See also:

Juvenile salmon

Eggs in different stages of development: In some, only a few cells grow on top of the yolk, in the lower right, the blood vessels surround the yolk, and in the upper left, the black eyes are visible, even the little lens.

Salmon fry hatching—the baby has grown around the remains of the yolk—visible are the arteries spinning around the yolk and small oil drops, also the gut, the spine, the main caudal blood vessel, the bladder, and the arcs of the gills.

Salmon eggs are laid in freshwater streams typically at high latitudes. The

eggs hatch into alevin or sac fry. The fry quickly develop into parr with camouflaging vertical stripes. The parr stay for six months to three years in their natal stream before becoming smolts, which are distinguished by their bright, silvery colour with scales that are easily rubbed off. Only 10% of all salmon eggs are estimated to survive to this stage.^[54]

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

insulin-like growth factor I, cortisol, and thyroid hormones,^[56]

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.[57]^{[page needed]}

Prior to spawning, depending on the

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 2.8 m² (30 sq ft).^[58] 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.^[53] 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.^[53]

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

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 corticosteroids.

• 
  Juvenile salmon, parr, grow up in the relatively protected natal river
• 
  The parr lose their camouflage bars and become smolt as they become ready for the transition to the ocean.
• 
  Male ocean-phase adult sockeye
• 
  Male spawning-phase adult sockeye

Diet

Salmon are mid-

fish eggs

(even those of other salmon).

As adults, salmon behave like other mid-sized pelagic fish, eating a variety of sea creatures including smaller forage fish such as lanternfish, herrings, sand lances, mackerels and barracudina. They also eat krill, squid and polychaete worms.^[60]

Ecology

See also: Salmon run

In the

forest ecosystem

.

In the case of

die after laying eggs 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.

Bears

riparian woodlands. The foliage of spruce trees up to 500 m (1,600 ft) from a stream where grizzlies fish salmon have been found to contain nitrogen originating from the fished salmon.^[66]

Beavers

juvenile salmon

.

An example of this was seen in the years following 1818 in the

trappers 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, salmon runs 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:^[67][68][69]

• Slow the rate at which nutrients are flushed from the water system; nutrients provided by adult salmon dying throughout the fall and winter remain available in the spring to newly hatched juveniles
• Provide deeper salmon pools where young salmon can avoid avian predators
• Increase productivity through
  detritus cycle^{[clarification needed}
  ]
• Create slow-water environments where juvenile salmon put the food they ingest into growth rather than into fighting currents
• Increase structural complexity with many physical niches where salmon can avoid predators

Beaver dams are able to nurture salmon juveniles in estuarine tidal marshes where the salinity is less than 10 ppm. Beavers build small dams of generally less than 60 cm (2 ft) high in channels in the myrtle zone^{[clarification needed]}. 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.^[70]

Lampreys

It has been discovered that rivers which have seen a decline or disappearance of anadromous lampreys, loss of the lampreys also affects the salmon in a negative way. Like salmon, anadromous lampreys stop feeding and die after spawning, and their decomposing bodies release nutrients into the stream. Also, along with species like rainbow trout and Sacramento sucker, lampreys clean the gravel in the rivers during spawning.^[71] Their larvae, called ammocoetes, are filter feeders which contribute to the health of the waters. They are also a food source for the young salmon, and being fattier and oilier, it is assumed predators prefer them over salmon offspring, taking off some of the predation pressure on smolts.^{[72][unreliable source?]} Adult lampreys are also the preferred prey of seals and sea lions, which can eat 30 lampreys to every salmon, allowing more adult salmon to enter the rivers to spawn without being eaten by the marine mammals.^[73][74]

Parasites

Main article: Diseases and parasites in salmon

According to Canadian biologist Dorothy Kieser, the

Haida Gwaii Islands

. The fish responds by walling off the parasitic infection into a number of cysts that contain milky fluid. This fluid is an accumulation of a large number of parasites.

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."^{[citation needed]}

Large numbers of highly populated, open-net salmon farms[A] 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.

As can be seen from the production chart at the left, the global capture reported by different countries to the

Farms

This section needs additional citations for verification. Please help improve this article by adding citations to reliable sources in this section. Unsourced material may be challenged and removed. Find sources: "Salmon" – news · newspapers · books · scholar · JSTOR (April 2023) (Learn how and when to remove this template message)

Salmon aquaculture is a major contributor to the world production of farmed finfish, representing about US$10 billion annually. Other commonly cultured fish species include tilapia, catfish, sea bass, carp and bream. Salmon farming is significant in Chile, Norway, Scotland, Canada and the Faroe Islands; it is the source for most salmon consumed in the United States and Europe. Atlantic salmon are also, in very small volumes, farmed in Russia and Tasmania, Australia.

Salmon are

Another form of salmon production, which is safer but less controllable, is to raise salmon in

Because of this, the ranching method has mainly been used by various public authorities and non-profit groups, such as the

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 artificial streams, 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.^{[citation needed]}

Farm-raised salmon are fed the carotenoids astaxanthin and canthaxanthin to match their flesh colour to wild salmon^[93] to improve their marketability.^[94] Wild salmon get these carotenoids, 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

Another possible alternative is a yeast-based coproduct of

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.^[95] 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.^{[96][failed verification]}

Management

Salmon population levels are of concern in the Atlantic and in some parts of the Pacific.^[98] The population of wild salmon declined markedly in recent decades, especially North Atlantic populations, which spawn in the waters of western Europe and eastern Canada, and wild salmon in the Snake and Columbia River systems in northwestern United States.

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.^[105] They are highly prized by sport fishers, but others worry about displacing native fish species.^[106] 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

Salmon is a popular

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.^[119] 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.^[119] 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.^[119] It is clear that further protection is needed for salmon, such as their habitats, where logging commonly occurs.

Fishing

History

The salmon has long been at the heart of the culture and livelihood of coastal dwellers, which can be traced as far back as 5,000 years when archeologists discovered

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.^[129]

The

The salmon is an important creature in several strands of Celtic mythology and poetry, which often associated them with wisdom and venerability. In Irish folklore, fishermen associated salmon with fairies and thought it was unlucky to refer to them by name.^[130] In Irish mythology, a creature called the Salmon of Knowledge^[131] plays key role in the tale The Boyhood Deeds of Fionn. In the tale, the Salmon will grant powers of knowledge to whoever eats it, and is sought by poet Finn Eces for seven years. Finally Finn Eces catches the fish and gives it to his young pupil, Fionn mac Cumhaill, to prepare it for him. However, Fionn burns his thumb on the salmon's juices, and he instinctively puts it in his mouth. In so doing, he inadvertently gains the Salmon's wisdom. Elsewhere in Irish mythology, the salmon is also one of the incarnations of both Tuan mac Cairill^[132] and Fintan mac Bóchra.^[133]

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 Cai and Bedwyr are led to the Salmon of Llyn Llyw, who lets them ride its back to the walls of Mabon's prison in Gloucester.^[134]

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.^[135]

Salmon are central spiritually and culturally to

References

Further reading

• Atlas of Pacific Salmon, Xanthippe Augerot and the State of the Salmon Consortium, University of California Press, 2005, hardcover, 152 pages,
  ISBN 0-520-24504-0
• Making Salmon: An Environmental History of the Northwest Fisheries Crisis, Joseph E. Taylor III, University of Washington Press, 1999, 488 pages,
  ISBN 0-295-98114-8
• Trout and Salmon of North America,
  ISBN 0-7432-2220-2
• Come back, salmon, By Molly Cone,
  ISBN 0-87156-572-2
  – A book for juveniles describes the restoration of 'Pigeon Creek'.
• The salmon: their fight for survival, By Anthony Netboy, 1973, Houghton Mifflin Co., 613 pages,
  ISBN 0-395-14013-7
• A River Lost, by Blaine Harden, 1996, WW Norton Co., 255 pages,
  ISBN 0-393-31690-4
  . (Historical view of the Columbia River system).
• River of Life, Channel of Death, by Keith C. Peterson, 1995, Confluence Press, 306 pages,
  ISBN 978-0-87071-496-2
  . (Fish and dams on the Lower Snake River.)
• Salmon, by Dr Peter Coates, 2006,
  ISBN 1-86189-295-0
• Lackey, Robert T (2000) "Restoring Wild Salmon to the Pacific Northwest: Chasing an Illusion?" In: Patricia Koss and Mike Katz (Eds) What we don't know about Pacific Northwest fish runs: An inquiry into decision-making under uncertainty, Portland State University, Portland, Oregon. Pages 91–143.
• Mills D (2001) "Salmonids" In: pp. 252–261, Steele JH, Thorpe SA and Turekian KK (2010) Marine Biology: A Derivative of the Encyclopedia of Ocean Sciences, Academic Press.
  ISBN 978-0-08-096480-5
  .
• NEWS January 31, 2007: U.S. Orders Modification of Klamath River – Dams Removal May Prove More Cost-Effective for allowing the passage of Salmon
• Salmon age and sex composition and mean lengths for the Yukon River area, 2004 / by Shawna Karpovich and Larry DuBois. Hosted by Alaska State Publications Program.
• "Studies in the Natural History of the Sacramento Salmon" .
  Popular Science Monthly
  . Vol. 61. July 1902.
• Trading Tails: Linkages Between Russian Salmon Fisheries and East Asian Markets. Shelley Clarke. (November 2007). 120pp.
  ISBN 978-1-85850-230-4
  .
• The Salmons Tale, one of the twelve Ionan Tales by Jim MacCool

External links

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