102-409: For the fish, see Salmon . Sammon may refer to: People [ edit ] Sammon (surname) , notable persons with the surname Sammon Other [ edit ] Jimon and Sammon , one of the factions of Tendai Buddhism Sammon projection , an algorithm that maps a high-dimensional space to a space of lower dimensionality Topics referred to by
204-501: 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
306-414: A couple of weeks. Once the salmon die in the river, they are either scavenged by other animals, or they decompose and release inorganic nutrients to the plankton in the river and the riparian vegetation in the floodplain . The Pacific salmon are a classic example of a semelparous animal, which reproduce only once in their lifetime. Semelparity is sometimes called "big bang" reproduction, since
408-442: A few species of salmon remain in fresh water throughout their life cycle, the majority are anadromous 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
510-473: 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. 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
612-639: A future in aquaculture that eliminates the need for land, freshwater, or fertilizer to raise fish. Salmon population levels are of concern in the Atlantic and in some parts of the Pacific. 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 run A salmon run
714-401: A gravel bed in the upper reaches of a stream or river. These are the salmon spawning grounds where salmon eggs are deposited, for safety, in the gravel. The salmon spawning grounds are also the salmon nurseries, providing a more protected environment than the ocean usually offers. After 2 to 6 months the eggs hatch into tiny larvae called sac fry or alevin . The alevin have a sac containing
816-569: 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
918-532: 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
1020-487: A pattern of spots and vertical bars. They remain in this stage for up to three years. As they approach the time when they are ready to migrate out to the sea the parr lose their camouflage bars and undergo a process of physiological changes which allows them to survive the shift from freshwater to saltwater. At this point salmon are called smolt . Smolt spend time in the brackish waters of the river estuary while their body chemistry adjusts their osmoregulation to cope with
1122-414: A range of biota, including poor swimmers. Skilled predators, such as bears , bald eagles and fishermen can await the salmon during the run. Normally solitary animals, grizzly bears congregate by streams and rivers when the salmon spawn. Predation from harbor seals , California sea lions , and Steller sea lions can pose a significant threat, even in river ecosystems. Black bears also fish
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#17331050490901224-452: A salmon depends on the position of the standing wave or hydraulic jump at the base of the fall, as well as how deep the water is. Fish ladders , or fishways, are specially designed to help salmon and other fish to bypass dams and other man-made obstructions, and continue on to their spawning grounds further upriver. Data suggest that navigation locks have a potential to be operated as vertical slot fishways to provide increased access for
1326-482: A shallow depression. The redd may contain up to 5,000 eggs, each about the size of a pea, covering 30 square feet (2.8 m ). The eggs usually range from orange to red. One or more males will approach the female in her redd, depositing his sperm, or milt, over her eggs. 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 will make as many as seven redds before her supply of eggs
1428-456: A spawning area will in fact survive to spawn." The eggs of a female salmon are called her roe . To lay her roe, the female salmon builds a spawning nest, called a redd , in a riffle with gravel as its streambed . A riffle is a relatively shallow length of stream where the water is turbulent and flows faster. She builds the redd by using her tail ( caudal fin ) to create a low-pressure zone, lifting gravel to be swept downstream, and excavating
1530-412: A technically demanding kind of sport fishing , not necessarily intuitive for beginning fishermen. A conflict exists between commercial fishermen and recreational fishermen for the right to salmon stock resources . Commercial fishing in estuaries and coastal areas is often restricted so enough salmon can return to their natal rivers where they can spawn and be available for sport fishing. On parts of
1632-619: A whole food web, we like to think of them as North America's answer to the Serengeti's wildebeest . Wolves normally hunt for deer. A 2008 study suggests that when the salmon run starts, wolves choose to fish for salmon, even if plenty of deer are still available. "Selecting benign prey such as salmon makes sense from a safety point of view. While hunting deer, wolves commonly incur serious and often fatal injuries. In addition to safety benefits we determined that salmon also provides enhanced nutrition in terms of fat and energy." The upper reaches of
1734-407: Is a dynamic equilibrium, controlled by genes, between homing and straying. If the spawning grounds have a uniform high quality, then natural selection should favour the descendants that home accurately. If the spawning grounds have a variable quality, then natural selection should favour a mixture of the descendants that stray and the descendants that home accurately. Prior to the run up the river,
1836-836: 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 carnivorous , and need to be fed meals produced from catching other wild forage fish and other marine organisms. Salmon farming leads to
1938-415: Is an annual fish migration event where many salmonid species, which are typically hatched in fresh water and live most of their adult life downstream in the ocean , swim back against the stream to the upper reaches of rivers to spawn on the gravel beds of small creeks . After spawning, all species of Pacific salmon and most Atlantic salmon die, and the salmon life cycle starts over again with
2040-487: Is because upstream freshwater bodies (especially creeks) typically do not have sufficient food available for the adult salmon diet, and they have used large amounts of energy swimming upriver, thus exhausting their own internal nutrient reserves. Spawning salmon also have programmed senescence , which is "characterized by immunosuppression and organ deterioration", making them more vulnerable to diseases. Most zombie fish die within days of spawning, but some can last up to
2142-687: Is called the salmon run. Anadromous salmon are Northern Hemisphere fish that spend their ocean phase in either the Atlantic Ocean or the Pacific Ocean . They do not thrive in warm water. There is only one species of salmon found in the Atlantic, commonly called the Atlantic salmon . These salmon run up rivers on both sides of the ocean. Seven different species of salmon inhabit the Pacific (see table), and these are collectively referred to as Pacific salmon . Five of these species run up rivers on both sides of
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#17331050490902244-412: Is cloudy. Likewise, electronically tagged salmon were observed to maintain direction even when swimming in water much too deep for sunlight to be of use. In 1973, it was shown that Atlantic salmon have conditioned cardiac responses to electric fields with strengths similar to those found in oceans. "This sensitivity might allow a migrating fish to align itself upstream or downstream in an ocean current in
2346-417: Is different from Wikidata All article disambiguation pages All disambiguation pages Salmon all other members of Salmoninae Salmon ( / ˈ s æ m ən / ; pl. : salmon) is the common name for several commercially important species of euryhaline ray-finned fish from the genera Salmo and Oncorhynchus of the family Salmonidae , native to tributaries of
2448-416: Is exhausted. Male pink salmon and some sockeye salmon develop pronounced humps just before they spawn. These humps may have evolved because they confer species advantages. The humps make it less likely the salmon will spawn in the shallow water at margins of the streambed, which tend to dry out during low water flows or freeze in winter. Further, riffles can contain many salmon spawning simultaneously, as in
2550-403: Is faced with two major challenges: it must supply energy suitable for swimming the river rapids, and it must supply the sperm and eggs required for the reproductive events ahead. The water in the estuary receives the freshwater discharge from the natal river. Relative to ocean water, this has a high chemical load from surface runoff . Researchers in 2009 found evidence that, as the salmon encounter
2652-441: 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 m (30 sq ft). The eggs usually range from orange to red. One or more males approach the female in her redd, depositing sperm, or milt, over
2754-946: 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 ectoparasites which feed on mucus, blood, and skin, and migrate and latch onto
2856-511: Is that there are geomagnetic and chemical cues which the salmon use to guide them back to their birthplace. The fish may be sensitive to the Earth's magnetic field, which could allow the fish to orient itself in the ocean, so it can navigate back to the estuary of its natal stream. Salmon have a strong sense of smell. Speculation about whether odours provide homing cues go back to the 19th century. In 1951, Hasler hypothesised that, once in vicinity of
2958-476: 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
3060-773: The Atlantic salmon , found in both sides of the North Atlantic , as well as more than 40 other species commonly named as trout . The genus Oncorhynchus contains 12 recognised species which occur naturally only in the North Pacific, six of which are known as Pacific salmon while the remainder are considered trout. Outside their native habitats, Chinook salmon have been successfully introduced in New Zealand and Patagonia , while coho , sockeye and Atlantic salmon have been established in Patagonia, as well. Both
3162-617: The Chilkat River in Alaska has particularly good spawning grounds. Each year these attract a run of up to half a million chum salmon . As the salmon run up the river, bald eagles arrive in their thousands to feast at the spawning grounds. This results in some of the world's largest congregations of bald eagles. The number of participating eagles is directly correlated with the number of spawning salmon. Residual nutrients from salmon can also accumulate downstream in estuaries. A 2010 study suggests
Sammon - Misplaced Pages Continue
3264-610: The Cook Inlet Aquaculture Association , as a way to increase salmon populations in situations where they have declined due to overharvesting , construction of dams 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,
3366-553: The Great Lakes of North America , Patagonia in South America and South Island of New Zealand . The Modern English term salmon is derived from Middle English : samoun , samon and saumon , which in turn are from Anglo-Norman : saumon , from Old French : saumon , and from Latin : salmō (which in turn might have originated from salire , meaning "to leap". ). The unpronounced "l" absent from Middle English
3468-484: The Japanese word for trout. On the other hand, the steelhead and sea trout , the anadromous forms of rainbow trout and brown trout respectively, are from the same genera as salmon and live identical migratory lives, but neither is termed "salmon" . The extinct Eosalmo driftwoodensis , the oldest known Salmoninae fish in the fossil record , helps scientists figure how the different species of salmon diverged from
3570-581: The North Atlantic ( Salmo ) and North Pacific ( Oncorhynchus ) basins. Other closely related fish in the same family include trout , char , grayling , whitefish , lenok and taimen , all coldwater fish of the subarctic and cooler temperate regions with some sporadic endorheic populations in Central Asia . Salmon are typically anadromous : they hatch in the shallow gravel beds of freshwater headstreams and spend their juvenile years in rivers , lakes and freshwater wetlands , migrate to
3672-518: The Pacific Northwest and Alaska , salmon are keystone species . The migration of salmon represent a massive retrograde nutrient transfer, rich in nitrogen , sulfur , carbon and phosphorus , from the ocean to the inland freshwater ecosystems . Predation by piscivorous land animals (such as ospreys , bears and otters ) along the journey serve to transfer the nutrients from the water to land, and decomposition of salmon carcass benefits
3774-456: The Pacific coast of Canada , the louse-induced mortality of pink salmon in some regions is commonly over 80%. The risk of injury caused by underwater pile driving has been studied by Dr. Halvorsen and her co-workers. The study concluded that the fish are at risk of injury if the cumulative sound exposure level exceeds 210 dB relative to 1 μPa s. As can be seen from the production chart at
3876-504: The Quaternary glaciation began the cycle of glacial advance and retreat. There are several other species of fish which are colloquially called "salmon" but are not true salmon. Of those listed below, the Danube salmon or huchen is a large freshwater salmonid closely related (from the same subfamily) to the seven species of salmon above, but others are fishes of unrelated orders , given
3978-654: The Salmo and Oncorhynchus genera also contain a number of trout species informally referred to as salmon. Within Salmo , the Adriatic salmon ( Salmo obtusirostris ) and Black Sea salmon ( Salmo labrax ) have both been named as salmon in English , although they fall outside the generally recognized seven salmon species. The masu salmon ( Oncorhynchus masou ) is actually considered a trout ("cherry trout") in Japan , with masu actually being
4080-615: The estuary or entrance to its birth river, salmon may use chemical cues which they can smell, and which are unique to their natal stream, as a mechanism to home onto the entrance of the stream. In 1978, Hasler and his students found that the way salmon locate their home rivers with such precision was because they could recognise its characteristic smell. They further demonstrated that the smell of their river becomes imprinted in salmon when they transform into smolts, just before they migrate out to sea. Homecoming salmon can also recognise characteristic smells in tributary streams as they move up
4182-497: The forest ecosystem . In the case of Pacific salmon , most (if not all) of the salmon that survive to reach the headwater spawning grounds will 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. Grizzly bears function as ecosystem engineers , capturing salmon and carrying them into adjacent dry land to eat
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4284-524: 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. 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
4386-473: The ocean as adults and live like sea fish , then return to their freshwater birthplace 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;
4488-590: 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 estuaries provide important habitat for many salmon species. They feed on terrestrial 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
4590-468: The North American West Coast salmon sport fishing has completely replaced inshore commercial salmon fishing. In most cases, the commercial value of a salmon sold as seafood can be several times less than the value attributed to the same fish caught by a sport fisherman. This is "a powerful economic argument for allocating stock resources preferentially to sport fishing". Salmon aquaculture
4692-558: 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,
4794-573: The Pacific, but two species are found only on the Asian side. In the early 19th century, Chinook salmon were successfully established in the Southern Hemisphere, far from their native range, in New Zealand rivers. Attempts to establish anadromous salmon elsewhere have not succeeded. The life cycle of an anadromous salmon begins and, if it survives the full course of its natural life, usually ends in
4896-500: The absence of fixed references." In 1988, researchers found iron, in the form of single domain magnetite , resides in the skulls of sockeye salmon. The quantities present are sufficient for magnetoception . Tagging studies have shown a small number of fish do not find their natal rivers, but travel instead up other, usually nearby streams or rivers. It is important some salmon stray from their home areas; otherwise new habitats could not be colonized. In 1984, Quinn hypothesized there
4998-432: 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
5100-455: The animal kingdom's more extreme migrations , the salmon return from the saltwater ocean back to a freshwater river to spawn afresh. After several years wandering huge distances in the ocean, most surviving salmon return to the same natal rivers where they were spawned. Then most of them swim up the rivers until they reach the very spawning ground that was their original birthplace. There are various theories about how this happens. One theory
5202-438: The base of the tail ( caudal peduncle ) of an opponent. The physical condition of the salmon deteriorates the longer they remain in fresh water. Once the salmon have spawned, most of them deteriorate rapidly (a.k.a. "spawned out") and soon die. Some deteriorating salmon are still alive, but their bodies have already begun the process of rotting, and these deteriorating salmon are sometimes colloquially called "zombie fish". This
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#17331050490905304-608: The common name "salmon" simply due to similar shapes, behaviors and niches occupied: 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. The smolt body chemistry changes, allowing them to live in salt water. While
5406-487: The density and diversity of many estuarine breeding birds in the summer "were strongly predicted by salmon biomass in the autumn". Anadromous salmon provide nutrients to these "diverse assemblages ... ecologically comparable to the migrating herds of wildebeest in the Serengeti ". In 1997, researchers noted that the future of salmon runs worldwide would depend on many factors, most of which are driven by human actions. Among
5508-430: 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
5610-536: The ecological impact they have on other wildlife is greater than would be expected in relation to their biomass . Most salmon species migrate during the autumn (September through November) , which coincides with the pre- winter activities of many hibernating animals. The annual salmon run can be a major feeding event for predators such as grizzly bears and bald eagles , as well as an important window period for sport fishermen . The post-spawning death of salmon also has important ecological consequences, because
5712-472: 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: 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
5814-821: 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 . Salmon are mid- level carnivores whose diet change according to their life stage. Salmon fry predominantly feed upon zooplanktons until they reach fingerling sizes, when they start to consume more aquatic invertebrates such as insect larvae , micro crustaceans and worms . As juveniles (parrs), they become more predatory and actively prey upon aquatic insects , small crustaceans, tadpoles and small bait fishes . They are also known to breach
5916-443: The fish. There they deposit nutrient-rich urine and feces and partially eaten carcasses. Bears preparing for hibernation tend to preferentially consume the more nutrient- and energy -rich salmon roes and brain over the actual flesh , and are estimated to discard up to half the salmon they've harvested uneaten on the forest floor, in densities that can reach 4,000 kg (8,800 lb) per hectare, providing as much as 24% of
6018-566: 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
6120-574: The higher salt levels they will encounter in the ocean. Smolt also grow the silvery scales which visually confuse ocean predators. When they have matured sufficiently in late spring, and are about 15 to 20 centimetres long, the smolt swim out of the rivers and into the sea. There they spend their first year as a post-smolt . Post-smolt form schools with other post-smolt, and set off to find deep-sea feeding grounds. They then spend up to four more years as adult ocean salmon while their full swimming ability and reproductive capacity develop. Then, in one of
6222-439: The image on the right. Predators, such as bears, will be more likely to catch the more visually prominent humped males, with their humps projecting above the surface of the water. This may provide a protective buffer for the females. Dominant male salmon defend their redds by rushing at and chasing intruders. They butt and bite them with the canine-like teeth they developed for the spawning event. The kypes are used to clamp around
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#17331050490906324-805: The key driving factors are (1) harvest of salmon by commercial, recreational, and subsistence fishing, (2) alterations in stream and river channels, including construction of dikes and other riparian corridor modifications, (3) electricity generation, flood control, and irrigation supplied by dams, (4) alteration by humans of freshwater, estuarine, and marine environments used by salmon, coupled with aquatic changes due to climate and ocean circulatory regimes, (5) water withdrawals from rivers and reservoirs for agricultural, municipal, or commercial purposes, (6) changes in climate caused at least in part by human activities, (7) competition from non-native fishes, (8) salmon predation by marine mammals, birds, and other fish species, (9) diseases and parasites, including those from outside
6426-681: The left, the global capture reported by different countries to the FAO of commercial wild salmon has remained fairly steady since 1990 at about one million tonnes per year. This is in contrast to farmed salmon (below) which has increased in the same period from about 0.6 million tonnes to well over two million tonnes. 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. Recreational salmon fishing can be
6528-458: 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
6630-449: The main river. They may also be sensitive to characteristic pheromones given off by juvenile conspecifics . There is evidence that they can "discriminate between two populations of their own species". The recognition that each river and tributary has its own characteristic smell, and the role this plays as a navigation aid, led to a widespread search for a mechanism or mechanisms that might allow salmon to navigate over long distances in
6732-644: The native region, and (10) reduced nutrient replenishment from decomposing salmon. In 2009, NOAA advised that continued runoff into North American rivers of three widely used pesticides containing neurotoxins would "jeopardize the continued existence" of endangered and threatened Pacific salmon. Global warming could see the end of some salmon runs by the end of the century, such as the Californian runs of Chinook salmon. A 2010 United Nations report said that increases in acidification of oceans would mean that shellfish such as pteropods , an important component of
6834-402: The new generation of hatchlings . Salmon are anadromous , spending their juvenile life in rivers or lakes, and then migrating out to sea where they spend adult lives and gain most of their body mass . When they reach sexual maturity , the adults return to the upstream rivers to reproduce . Usually they return with uncanny precision to the natal river where they were born, and even to
6936-513: The night because their black fur is easily spotted by salmon in the daytime. In 2009, researchers compared the foraging success of black bears with the white-coated Kermode bear , a morphed subspecies of the black bear. They found the Kermode bear had no more success catching salmon at night time, but had greater success than the black bears during the day. Otters are also common predators. In 2011, researchers showed that when otters predate salmon,
7038-533: The ocean salmon diet, would be finding it more difficult to build their aragonite shells. There were concerns that this too could endanger future salmon runs. In a 1982 video game called Salmon Run , the player takes the role of Sam the Salmon, swimming upriver to mate. Along the way he encounters waterfalls, a bear, fishermen, and seagulls. In the Disney animated feature film, Brother Bear , Kenai and Koda reached
7140-645: The ocean where they can recover and spawn again the next season. In the Pacific Northwest and Alaska, salmon is a keystone species , supporting wildlife from birds to bears and otters. The bodies of salmon represent a transfer of nutrients from the ocean, rich in nitrogen, sulfur, carbon and phosphorus, to the forest ecosystem . Grizzly bears function as ecosystem engineers , capturing salmon and carrying them into adjacent wooded areas. There they deposit nutrient-rich urine and faeces and partially eaten carcasses. It has been estimated that bears leave up to half
7242-413: The ocean. They need high swimming and leaping abilities to battle the rapids and other obstacles the river may present, and they need a full sexual development to ensure a successful spawn at the end of the run. All their energy goes into the physical rigours of the journey and the dramatic morphological transformations they must still complete before they are ready for the spawning events ahead. The run up
7344-411: The open ocean. In 1977, Leggett identified, as mechanisms worth investigating, the use of the sun for navigation, and orientation to various possible gradients, such as temperature, salinity or chemicals gradients, or geomagnetic or geoelectric fields. There is little evidence salmon use clues from the sun for navigation. Migrating salmon have been observed maintaining direction at nighttime and when it
7446-446: The parasitic infection into a number of cysts that contain milky fluid. This fluid is an accumulation of a large number of parasites. 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
7548-525: 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, 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 anglers . Many species of salmon have since been introduced and naturalized into non-native environments such as
7650-517: 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. According to Canadian biologist Dorothy Kieser, the myxozoan parasite Henneguya salminicola is commonly found in the flesh of salmonids. It has been recorded in the field samples of salmon returning to the Haida Gwaii Islands . The fish responds by walling off
7752-408: 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
7854-466: 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 carotenoids , primarily astaxanthin, from eating shellfish and krill . One proposed alternative to
7956-408: The remainder of the yolk, and they stay hidden in the gravel while they feed on the yolk. When the yolk has gone they must find food for themselves, so they leave the protection of the gravel and start feeding on plankton . At this point the baby salmon are called fry . At the end of the summer the fry develop into juvenile fish called parr . Parr feed on small invertebrates and are camouflaged with
8058-420: The resulting drop in salinity and increase in olfactory stimulation, two key metabolic changes are triggered: there is a switch from using red muscles for swimming to using white muscles, and there is an increase in the sperm and egg load. "Pheromones at the spawning grounds [trigger] a second shift to further enhance reproductive loading." The salmon also undergo radical morphological changes as they prepare for
8160-509: The riparian zones the salmon reach. The nutrients can also be washed downstream into estuaries where they accumulate and provide significant support for invertebrates and estuarine-breeding waterbirds . Most salmon are anadromous , a term which comes from the Greek anadromos , meaning "running upward". Anadromous fish grow up mostly in the saltwater in oceans. When they have matured they migrate or "run up" freshwater rivers to spawn in what
8262-604: The river can be exhausting, sometimes requiring the salmon to battle hundreds of miles upstream against strong currents and rapids. They cease feeding during the run. Chinook and sockeye salmon from central Idaho must travel 900 miles (1,400 km) and climb nearly 7,000 feet (2,100 m) before they are ready to spawn. Salmon deaths that occur on the upriver journey are referred to as en route mortality . Salmon negotiate waterfalls and rapids by leaping or jumping. They have been recorded making vertical jumps as high as 3.65 metres (12 ft). The height that can be achieved by
8364-407: 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
8466-634: The salmon can "sniff them out". They demonstrated that once otters have eaten salmon, the remaining salmon could detect and avoid the waters where otter faeces was present. The term prespawn mortality is used to refer to fish that arrive successfully at the spawning grounds, and then die without spawning. Prespawn mortality is surprisingly variable, with one study observing rates between 3% and 90%. Factors that contribute to these mortalities include high temperatures, high river discharge rates, and parasites and diseases. "At present there are no reliable indicators to predict whether an individual arriving at
8568-503: 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
8670-546: The salmon they harvest on the forest floor, in densities that can reach 4,000 kilograms per hectare, providing as much as 24% of the total nitrogen available to the 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 fished salmon. Salmon continue to surprise us, showing us new ways in which their oceanic migrations eventually permeate entire terrestrial ecosystems. In terms of providing food and nutrients to
8772-409: The salmon undergo profound physiological changes. Fish swim by contracting longitudinal red muscle and obliquely oriented white muscles. Red muscles are used for sustained activity, such as ocean migrations. White muscles are used for bursts of activity, such as bursts of speed or jumping. As the salmon comes to end of its ocean migration and enters the estuary of its natal river, its energy metabolism
8874-456: The salmon. Black bears usually operate during the day, but when it comes to salmon they tend to fish at night. This is partly to avoid competition with the more powerful brown bears, but it is also because they catch more salmon at night. During the day, salmon are very evasive and attuned to visual clues, but at night they focus on their spawning activities, generating acoustic clues the bears tune into. Black bears may also fish for salmon during
8976-408: The same term [REDACTED] This disambiguation page lists articles associated with the title Sammon . If an internal link led you here, you may wish to change the link to point directly to the intended article. Retrieved from " https://en.wikipedia.org/w/index.php?title=Sammon&oldid=864818339 " Category : Disambiguation pages Hidden categories: Short description
9078-400: The significant nutrients in their carcasses , rich in nitrogen , sulfur , carbon and phosphorus , are transferred from the ocean and released to inland aquatic ecosystems , terrestrial animals (such as bears) and the wetlands and riparian woodlands adjacent to the rivers. This has knock-on effects not only for the next generation of salmon, but to every wildlife species living in
9180-421: 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 1,400 km (900 mi) and climb nearly 2,100 m (7,000 ft) from the Pacific Ocean as they return to spawn. Condition tends to deteriorate
9282-553: The single reproductive event of semelparous organisms is usually large and fatal to the spawners. It is an evolutionary strategy that concentrates all available resources into maximizing reproduction, at the expense of individual organism's life, which is common among insects but rare among vertebrates . All six species of Pacific salmons live for many years in the ocean before swimming to the freshwater stream of its birth, spawning, and then dying. Most Atlantic salmon also die after spawning, but about 5 to 10% (mostly female) return to
9384-546: 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
9486-421: The spawning event ahead. All salmon lose the silvery blue they had as ocean fish, and their colour darkens, sometimes with a radical change in hue. Salmon are sexually dimorphic , and the male salmon develop canine-like teeth and their jaws develop a pronounced curve or hook ( kype ). Some species of male salmon grow large humps. Salmon start the run in peak condition, the culmination of years of development in
9588-458: The stream. Also, along with species like rainbow trout and Sacramento sucker , lampreys clean the gravel in the rivers during spawning. 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. Adult lampreys are also
9690-534: 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 hatcheries until they are old enough to become independent. They are released into rivers in an attempt to increase
9792-488: The time the studies were conducted, stocks from the middle and upper reaches of large river systems in British Columbia such as Fraser , Skeena , Nass 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
9894-467: The total nitrogen available to the 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. Beavers also function as ecosystem engineers; in the process of tree-cutting and damming , beavers alter the local ecosystems extensively. Beaver ponds can provide critical habitat for juvenile salmon . An example of this
9996-597: 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, proteinaceous fermentation biomass. Substituting such products for engineered feed can result in equal (sometimes enhanced) growth in fish. With its increasing availability, this would address
10098-844: The very spawning ground of their birth. It is thought that, when they are in the ocean, they use magnetoreception to locate the general position of their natal river, and once close to the river, that they use their sense of smell to home in on the river entrance and even their natal spawning ground. Trout , which are sister species of salmon, also perform similar migrations, although they mostly move potamodromously between creeks and large freshwater lakes, except for some coastal/ estuary subspecies such as steelhead and sea trout that migrate seasonally between salty / brackish and fresh water just like salmon do. There are also landlocked populations of some salmon species that have adapted to spend their entire life in freshwater like trout. In Northwest America , salmons are keystone species , which means
10200-417: The water to attack terrestrial insects such as grasshoppers and dragonflies , as well as consuming 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 . In
10302-435: Was later added as a Latinisation to make the word closer to its Latin root. The term salmon has mostly displaced its now dialectal synonym lax , in turn from Middle English : lax , from Old English : leax , from Proto-Germanic : * lahsaz from Proto-Indo-European : *lakso- . The seven commercially important species of salmon occur in two genera of the subfamily Salmoninae . The genus Salmo contains
10404-621: 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 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
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