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112-541: The rainbow trout ( Oncorhynchus mykiss ) is a species of trout native to cold-water tributaries of the Pacific Ocean in North America and Asia. The steelhead (sometimes called steelhead trout ) is an anadromous (sea-run) form of the coastal rainbow trout ( O. m. irideus ) or Columbia River redband trout ( O. m. gairdneri ) that usually returns to freshwater to spawn after living two to three years in
224-410: A steelhead subspecies, generally accepted as coming from Sonoma Creek . The rainbow trout of New Zealand still show the steelhead tendency to run up rivers in winter to spawn. In Australia, the rainbow trout was introduced in 1894 from New Zealand and is an extremely popular gamefish in recreational angling. Despite severely impacting the distribution and abundance of native Australian fish, such as
336-451: A backbone like snails, worms, or insects. They also eat flies, and most people who try to use lures to fish trout mimic flies because they are one of trout's most fed on meals. Trout enjoy certain land animals, including insects like grasshoppers. They also eat small animals like mice when they fall in. (Although only large trout have mouths capable of eating mice.) They consume a diet of aquatic life like minnows or crawfish as well. Trout have
448-419: A bed of fine gravel in a riffle above a pool. A female trout clears a redd in the gravel by turning on her side and beating her tail up and down. Female rainbow trout usually produce 2000 to 3000 4-to-5-millimetre ( 5 ⁄ 32 – 3 ⁄ 16 in) eggs per kilogram of weight. During spawning, the eggs fall into spaces between the gravel, and immediately the female begins digging at the upstream edge of
560-747: A broad reddish stripe along the lateral line , from gills to the tail, which is most vivid in breeding males. Wild-caught and hatchery -reared forms of the species have been transplanted and introduced for food or sport in at least 45 countries and every continent except Antarctica. Introductions to locations outside their native range in the United States, Southern Europe, Australia, New Zealand, and South America have damaged native fish species. Introduced populations may affect native species by preying on them, out-competing them, transmitting contagious diseases (such as whirling disease ), or hybridizing with closely related species and subspecies. The rainbow trout
672-415: A century ago, but its range has spread and it has appeared in most of Europe, northern Asia, the U.S., South Africa and other countries. In the 1980s, M. cerebralis was found to require Tubifex tubifex (a kind of segmented worm ) to complete its life cycle . The parasite infects its hosts with its cells after piercing them with polar filaments ejected from nematocyst -like capsules. This parasite
784-622: A century of hatchery stocking. Genetic analysis shows that the South Central California Coast and Southern California populations from Malibu Creek north, including the San Gabriel River , Santa Ana River , and San Mateo Creek , are not hatchery strains. Steelhead from Topanga Creek and the Sweetwater River were partly, and those from San Juan Creek completely, of hatchery origin. Genetic analysis has also shown that
896-408: A condition known as physostome . Unlike many other physostome fish, trout do not use their bladder as an auxiliary device for oxygen uptake, relying solely on their gills . There are many species, and even more populations, that are isolated from each other and morphologically different. However, since many of these distinct populations show no significant genetic differences, what may appear to be
1008-539: A decline or even elimination of whole cohorts of fish. The parasite M. cerebralis was first recorded in North America in 1956 in Pennsylvania, but until the 1990s, whirling disease was considered a manageable problem affecting only rainbow trout in hatcheries. It eventually became established in the natural waters of the Rocky Mountain states ( Colorado , Wyoming, Utah , Montana , Idaho , New Mexico ), where it
1120-595: A diverse diet they follow; they have plenty of different oppositions. Compared to other salmonids, trout are somewhat more bony , but the flesh is generally considered delicious, and the texture is often indistinguishable from that of salmon . The flavor of the flesh is heavily influenced by the diet of the fish. For example, trout that have been feeding on crustaceans tend to be more flavorful than those feeding primarily on insects and larvae . Because of their popularity, trout are often raised on fish farms and then stocked into heavily fished waters, in an effort to mask
1232-449: A fish caught on Saskatchewan 's Lake Diefenbaker by Sean Konrad on September 5, 2009, which weighed 48 lb (22 kg). The record is controversial because the fish was a genetically modified triploid and was part of a large number of triploid rainbow trout which escaped from an aquaculture facility. Rainbow trout is sometimes used as a biological indicator for water quality in water purification facilities. Rainbow trout
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#17328546227091344-600: A force the native salmon and trout have to reckon with. Not only do the non-native fish drive the native fish to occupy new niches, but they also try to hybridize with them, contaminating the native gene construction. As more hybrids between native and non-native fish are formed, the lineage of the pure fish is continuously being contaminated by other species and soon may no longer represent the sole native species. The Rio Grande cutthroat trout ( Oncorhynchus clarki virginalis ) are susceptible to hybridization with other salmonids such as rainbow trout ( Oncorhynchus mykiss ) and yield
1456-432: A generally appealing flavor. Seafood Watch ranks farmed rainbow trout as a "Best Choice" fish for human consumption. In Montana , it is illegal to sell or market wild-caught rainbow trout, which are legally classified as game fish. The color and flavor of the flesh depend on the diet and freshness of the trout. Farmed trout and some populations of wild trout, especially anadromous steelhead, have reddish or orange flesh as
1568-696: A good fight when caught with a hook and line . As trout are predatory fish , lure fishing (which use replica baits called lures to imitate live prey) is the predominant form of sport fishing involving trout, although traditional bait fishing techniques using floats and/or sinkers (particularly with moving live baits such as baitfish , crayfish or aquatic insects ) are also successful, especially against stocked trout that are hatchery / farm -raised and thus more accustomed to artificial feeds . Many species of trout, most noticeably rainbow trout and brown trout , have been widely introduced into waterbodies outside of their native ranges purely for
1680-477: A large number of species is considered a much smaller number of distinct species by most ichthyologists . The trout found in the eastern United States are a good example of this. The brook trout , the aurora trout , and the (extinct) silver trout all have physical characteristics and colorations that distinguish them, yet genetic analysis shows that they are one species, Salvelinus fontinalis . Lake trout ( Salvelinus namaycush ), like brook trout, belong to
1792-479: A large part of the diet. In general, trout longer than about 300 millimetres (12 in) prey almost exclusively on fish, where they are available. Adult trout will devour smaller fish up to one-third of their length. Trout may feed on shrimp , mealworms , bloodworms , insects , small animal parts, and eel . Trout who swim the streams love to feed on land animals, aquatic life, and flies. Most of their diet comes from macroinvertebrates, or animals that do not have
1904-515: A mechanism were under discussion. The current system of "modified priority" was essentially put in place at the Cambridge Congress of 1930. By the 19th century, the Linnaean binomial system was generally adopted by zoologists. In doing so, many zoologists tried to dig up the oldest possible scientific names as a result of which proper and consistent names prevailing at the time including those by
2016-429: A new " cutbow " trout, which is a contamination of both lineages’ genes. One solution to this issue is implemented by New Mexico Department of Game and Fish hatcheries : stock only sterile fish in river streams. Hatcheries serve as a reservoir of fish for recreational activities but growing and stocking non-sterile fish would worsen the hybridization issue on a quicker, more magnified time scale. By stocking sterile fish,
2128-515: A plant can bear the same name, which is then called a hemi homonym . There are formal provisions for making exceptions to the principle of priority under each of the Codes. If an archaic or obscure prior name is discovered for an established taxon, the current name can be declared a nomen conservandum (botany) or conserved name (zoology), and so conserved against the prior name. Conservation may be avoided entirely in zoology as these names may fall in
2240-748: A rainbow trout species that can be completely fed on a vegan diet through genetic selection. Research from a study team led by USDA research geneticist Dr. Ken Overturf concluded that such natural genetic variation of vegan trouts does exist and believe they can produce rainbow trouts that can be completely fed on a 100% plant-based diet. Populations of many rainbow trout subspecies, including anadromous forms (steelhead) of O. m. irideus (coastal rainbow trout) and O. m. gairdneri (Columbia River redband trout), have declined in their native ranges due to over-harvest, habitat loss, disease, invasive species , pollution and hybridization with other subspecies, and some introduced populations, once healthy, have declined for
2352-637: A result of high astaxanthin levels in their diets. Astaxanthin is a powerful antioxidant that may be from a natural source or a synthetic trout feed. Rainbow trout raised to have pinker flesh from a diet high in astaxanthin are sometimes sold in the U.S. with labeling calling them "steelhead". As wild steelhead are in decline in some parts of their range, farmed rainbow trout are viewed as a preferred alternative. In Chile and Norway , rainbow trout farmed in saltwater sea cages are sold labeled as steelhead. Trout can be cooked as soon as they are cleaned, without scaling , skinning , or filleting . If cooked with
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#17328546227092464-682: A similar latitude. The range of coastal rainbow trout ( O. m. irideus ) extends north from the Pacific basin into tributaries of the Bering Sea in northwest Alaska, while forms of the Columbia River redband trout ( O. m. gairdneri ) extend east into the upper Mackenzie River and Peace River watersheds in British Columbia and Alberta, Canada, which eventually drain into the Beaufort Sea , part of
2576-543: A single species. The International Code of Nomenclature for algae, fungi, and plants (ICN) defines it as: "A right to precedence established by the date of valid publication of a legitimate name or of an earlier homonym, or by the date of designation of a type." Basically, it is a scientific procedure to eliminate duplicate or multiple names for a species, for which Lucien Marcus Underwood called it "the principle of outlaw in nomenclature". The principle of priority has not always been in place. When Carl Linnaeus laid
2688-588: A source of nutrients for scavengers , detrivores and riparian florae , making trout keystone species across aquatic and terrestrial ecosystems . The name "trout" is commonly used for many (if not most) species in three of the seven genera in the subfamily Salmoninae: Salmo ( Atlantic ), Oncorhynchus ( Pacific ) and Salvelinus ( circum - arctic ). Fish species referred to as trout include: Trout that live in different environments can have dramatically different colorations and patterns. Mostly, these colors and patterns form as camouflage , based on
2800-529: Is a non-profit organization dedicated to the conservation of North American freshwater streams, rivers, and associated upland habitats for trout, salmon, other aquatic species, and people. A typical TU project is the Circle Creek Fish Passage Project, in which access to a spawning stream is being improved for steelhead and other salmonid species. The Wild Salmon Center , an international coalition of Russian, Canadian and U.S. scientists, sponsors
2912-447: Is a principle in biological taxonomy by which a valid scientific name is established based on the oldest available name. It is a decisive rule in botanical and zoological nomenclature to recognise the first binomial name (also called binominal name in zoology) given to an organism as the correct and acceptable name. The purpose is to select one scientific name as a stable one out of two or more alternate names that often exist for
3024-402: Is allowed for fossil-taxa that represent different parts, life-history stages, or preservational states of what may have been a single organismal taxon or even a single individual (Art. 1.2). Priority has two aspects: Note that nomenclature for botany and zoology is independent, and the rules of priority regarding homonyms operate within each discipline but not between them. Thus, an animal and
3136-412: Is also used for some similar-shaped but non-salmonid fish, such as the spotted seatrout/speckled trout ( Cynoscion nebulosus , which is actually a croaker ). Trout are closely related to salmon and have similar migratory life cycles . Most trout are strictly potamodromous , spending their entire lives exclusively in freshwater lakes , rivers and wetlands and migrating upstream to spawn in
3248-556: Is common. Rainbow trout can also be caught on various live and dead natural baits . Many anglers consider the rainbow trout the hardest-fighting trout species, as this fish is known for leaping when hooked and putting up a powerful struggle. It is considered one of the top five sport fish in North America, and the most important game fish west of the Rocky Mountains . There are tribal commercial fisheries for steelhead in Puget Sound ,
3360-460: Is damaging several sport fishing rivers. Some streams in the western U.S. lost 90 percent of their trout. Whirling disease threatens recreational fishing, which is important for the tourism industry, a key component of the economies of some U.S. western states. For example, in 2005 anglers in Montana spent approximately $ 196,000,000 in activities directly related to trout fishing in the state. Some of
3472-522: Is evidence North American fishes are unable to digest the tiny but hard shells of the mud snail, and that their presence may result in poor growth outcomes for rainbow trout. The mud snail was first detected in the U.S. in Idaho's Snake River in 1987. Since then, the snail has spread to the Madison River , Firehole River, and other watercourses around Yellowstone National Park, and has been discovered throughout
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3584-483: Is included in the list of the top 100 globally invasive species . Other introductions into waters previously devoid of fish or with severely depleted stocks of native fish have created sport fisheries , such as the Great Lakes and Wyoming 's Firehole River . Some local populations of specific subspecies, or in the case of steelhead, distinct population segments , are listed as either threatened or endangered under
3696-546: Is isolated in Lake Crescent (Washington), is threatened by the loss of its only spawning grounds in the Lyre River to siltation and other types of habitat degradation. Myxobolus cerebralis is a myxosporean parasite of salmonids (salmon, trout, and their allies) that causes whirling disease in pen farmed salmon and trout and also in wild fish populations . It was first described in rainbow trout introduced to Germany
3808-661: Is much cheaper than the imported Atlantic salmon and the meat are indistinguishable to the untrained eyes, and the news of trout being sold as salmon triggered public scrutiny accusing seafood suppliers of bait-and-switch and unethical business practices . Also, many people believe freshwater trout are more prone to parasites than oceanic salmon (even though both live in freshwater for significant periods of their life cycles) and thus unsafe for raw eating . One fillet of trout (about 79 g or 2.8 oz) contains: Trout are very popular freshwater game fish highly prized especially by creek fishermen, because they generally put up
3920-555: Is popular in Western cuisine ; both wild-caught and farmed fish are eaten. It has tender flesh and a mild, somewhat nutty flavor. Wild fish has a stronger, gamier taste than farmed fish. While the taste of wild-caught trout is often promoted as superior, rainbow trout and "steelhead" sold in American restaurants is typically farmed . Farmed rainbow trout are considered one of the safest fish to eat and are noted for high levels of vitamin B and
4032-463: Is virtually impossible to define a particular color pattern as belonging to a specific breed; however, in general, wild fish are claimed to have more vivid colors and patterns. Trout have fins entirely without spines, and all of them have a small adipose fin along the back, near the tail. The pelvic fins sit well back on the body, on each side of the anus. The swim bladder is connected to the esophagus , allowing for gulping or rapid expulsion of air,
4144-597: The Columbia River who provided Richardson with specimens. In 1855, William P. Gibbons, the curator of Geology and Mineralogy at the California Academy of Sciences , found a population and named it Salmo iridia (Latin: rainbow), later corrected to Salmo irideus . These names faded once it was determined that Walbaum's description of type specimens was conspecific and therefore had precedence . In 1989, morphological and genetic studies indicated that trout of
4256-608: The Endangered Species Act . The steelhead is the official state fish of Washington . The scientific name of the rainbow trout is Oncorhynchus mykiss . The species was originally named by German naturalist and taxonomist Johann Julius Walbaum in 1792 based on type specimens from the Kamchatka Peninsula in Siberia. Walbaum's original species name, mykiss , was derived from the local Kamchatkan name used for
4368-579: The Pacific Basin were genetically closer to Pacific salmon ( Oncorhynchus species) than to the Salmo s – brown trout ( Salmo trutta ) or Atlantic salmon ( Salmo salar ) of the Atlantic Basin . Thus, in 1989, taxonomic authorities moved the rainbow, cutthroat , and other Pacific Basin trout into the genus Oncorhynchus . Walbaum's name had precedence, so the species name Oncorhynchus mykiss became
4480-495: The Washington coast, and in the Columbia River , but there has been controversy regarding overharvesting of native stocks . The highly desirable sporting qualities and adaptability of the rainbow trout to hatchery rearing and new habitats resulted in it being introduced to many countries around the world by or at the behest of sport fishermen. Many of these introductions have resulted in environmental and ecological problems, as
4592-691: The adipose fin is a management tool used to identify hatchery-reared fish. Rainbow trout, including steelhead forms, generally spawn in early to late spring (January to June in the Northern Hemisphere and September to November in the Southern Hemisphere) when water temperatures reach at least 6 to 7 °C (42 to 44 °F). The maximum recorded lifespan for a rainbow trout is 11 years. Freshwater resident rainbow trout usually inhabit and spawn in small to moderately large, well-oxygenated, shallow rivers with gravel bottoms. They are native to
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4704-517: The alluvial or freestone streams that are typical tributaries of the Pacific basin but introduced rainbow trout have established wild, self-sustaining populations in other river types such as bedrock and spring creeks . Lake-resident rainbow trout are usually found in moderately deep, cool lakes with adequate shallows and vegetation to support the production of sufficient food sources. Lake populations generally require access to gravelly-bottomed streams to be self-sustaining. Spawning sites are usually
4816-645: The climbing galaxias , millions of rainbow and other trout species are released annually from government and private hatcheries. The closest resemblance of seema trout and other trout family can be found in the Himalayan Region of India, Nepal, Bhutan, Pakistan and in Tian Shan mountains of Kyrgyzstan . Trout generally feed on other fish, and soft-bodied aquatic invertebrates , such as flies , mayflies , caddisflies , stoneflies , mollusks and dragonflies . In lakes, various species of zooplankton often form
4928-674: The mitochondria are the most important organelle contributing to tissue damage because of their role in metabolism and production of reactive oxygen species . In a study done by Almaida-Pagàn et al., researchers identified changes to the heart and brain mitochondrial membrane phospholipid composition in rainbow trout due to the differing levels of oxidative stress each organ faced during a high-stress time such as rapid growth and development. Stock rainbow trout of ages 1, 2, and 4 years had their heart and brain mitochondria isolated and analyzed for fatty acid composition. The tissues showed an overall similar percentage of total phospholipids but differed in
5040-404: The "final epithet" of the name is combined with the new genus name, with any adjustments necessary for Latin grammar, for example: In zoology, the principle of priority applies to names between the rank of superfamily and subspecies (not to varieties, which are below the rank of subspecies). Also unlike in botany, the authorship of new combinations is not tracked, and only the original authority
5152-445: The 19th century, the principle gradually came to be accepted by almost all botanists, but debate continued to rage over the conditions under which the principle might be ignored. Botanists on one side of the debate argued that priority should be universal and without exception. This would have meant a one-off major disruption as countless names in current usage were overturned in favour of archaic prior names. In 1891, Otto Kuntze , one of
5264-536: The 3,400 km (2,100 mi) river system. Neither method of control is 100% effective and are best regarded as methods to change the relative population sizes of fish species. Steelhead populations in parts of its native range have declined due to a variety of human and natural causes. While populations in Alaska and along the British Columbia coast are considered healthy, populations in Kamchatka and some populations along
5376-491: The Arctic Ocean. Since 1875, the rainbow trout has been widely introduced into suitable lacustrine and riverine environments throughout the United States and around the world. Many of these introductions have established wild, self-sustaining populations. Since 1870, rainbow trout have been artificially propagated in fish hatcheries to restock streams and introduce them into non-native waters. The first rainbow trout hatchery
5488-589: The Code or by any ruling of the Commission. According to the ICZN preamble: Priority of publication is a basic principle of zoological nomenclature; however, under conditions prescribed in the Code its application may be modified to conserve a long-accepted name in its accustomed meaning. When stability of nomenclature is threatened in an individual case, the strict application of the Code may under specified conditions be suspended by
5600-821: The Columbia River. Winter-run fish are ready to spawn when they leave the ocean, typically between November and April, and spawn shortly after returning to fresh water. Winter-run fish generally spawn in shorter, coastal rivers typically found along the Olympic Peninsula and British Columbia coastline, and summer-run fish are found in some shorter, coastal streams. Once steelhead enter riverine systems and reach suitable spawning grounds, they spawn just like resident freshwater rainbow trout. During periods of rapid growth and aging, trout display high levels of metabolic activity. High metabolic activity has been correlated with increased levels of oxidative stress and decreased machinery repair in rainbow trout. During high oxidative stress,
5712-665: The Garmat Ali River in Iraq since 2008), Europe (since 1859 in England), and North America (U.S. and Canada: Thunder Bay in Ontario since 2001, British Columbia since July 2007), most likely inadvertently during human activity. It can reach concentrations greater than 500,000 per square metre (46,000/sq ft), endangering the food chain by outcompeting native snails and water insects for food, leading to sharp declines in native populations. There
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#17328546227095824-507: The Great Lakes is as high as 70 percent. As young steelhead transition from freshwater to saltwater, a process called " smoltification " occurs where the trout undergoes physiological changes to allow it to survive in seawater. There are genetic differences between freshwater and steelhead populations that may account for the smoltification in steelhead. Juvenile steelhead may remain in the river for one to three years before smolting and migrating to sea. Individual steelhead populations leave
5936-681: The International Commission on Zoological Nomenclature. In botany, the principle if defined by the Shenzhen Code (or the International Code of Nomenclature for algae, fungi, and plants ) in 2017 in its article 11: Each family or lower-ranked taxon with a particular circumscription, position, and rank can bear only one correct name. Special exceptions are made for nine families and one subfamily for which alternative names are permitted (see Art. 18.5 and 19.8). The use of separate names
6048-557: The Kamchatka Steelhead Project, a 20-year (1994–2014) scientific program to study and conserve the present condition of Kamchatkan steelhead ("mikizha"), a species listed in the Red Data Book of Russia . Other high-profile organizations involved in rainbow trout conservation include California Trout , which protects wild trout and other salmonids in the waters of California. The Steelhead Society of British Columbia promotes
6160-788: The Pacific basin, from the Kamchatka Peninsula in Russia, east along the Aleutian Islands , throughout southwest Alaska, the Pacific coast of British Columbia and southeast Alaska, and south along the west coast of the U.S. to northern Mexico. It is claimed that the Mexican forms of Oncorhynchus mykiss represent the southernmost native range of any trout or salmon ( Salmonidae ), though the Formosan landlocked salmon ( O. masou formosanus ) in Asia inhabits
6272-598: The U.S. In Tasmania they are commercially propagated in sea cages and are known as ocean trout , although they are the same species. Like salmon, steelhead return to their original hatching grounds to spawn . Similar to Atlantic salmon, but unlike their Pacific Oncorhynchus salmonid kin, steelhead are iteroparous (able to spawn several times, each time separated by months) and make several spawning trips between fresh and salt water, although fewer than 10 percent of native spawning adults survive from one spawning to another. The survival rate for introduced populations in
6384-501: The U.S. West Coast are in decline. The U.S. National Marine Fisheries Service has 15 identified distinct population segments , in Washington , Oregon , and California. Eleven of these populations are listed under the U.S. Endangered Species Act , ten as threatened and one as endangered. One distinct population segment on the Oregon coast is designated a U.S. Species of Concern . The Southern California distinct population segment , which
6496-627: The U.S. by the Environmental Protection Agency . Once the chemicals have dissipated, native trout are released into the river. Another method is to use electrofishing which enables the fish to be caught alive and harvested or re-located. This technique has been used in the Great Smokey Mountains National Park to rid it of rainbow trout that were introduced in the 1930s and have thrived ever since. They are hoping to re-establish native brook trout in at least some of
6608-578: The U.S., Iran, Turkey, the United Kingdom, and Lesotho . While the U.S. rainbow trout industry as a whole is viewed as ecologically responsible, trout raised elsewhere are not necessarily farmed with the same methods. About three-quarters of U.S. production comes from Idaho, particularly the Snake River area, due in part to the quality and temperature of the water available there. California and Washington also produce significant numbers of farmed trout. In
6720-509: The U.S., and nearly all domestic production is consumed within the country; very little is exported. The U.S. produces about 7 percent of the world's farmed trout. Rainbow trout, especially those raised in farms and hatcheries, are susceptible to enteric redmouth disease . A considerable amount of research has been conducted on redmouth disease, given its serious implications for rainbow trout farming. The disease does not infect humans. There have been recent interest and efforts in introducing
6832-483: The U.S., there are hundreds of hatcheries operated by the United States Fish and Wildlife Service and various state agencies and tribal governments propagating rainbow trout for conservation and recreational sport fishing. Six of ten Canadian provinces have rainbow trout farms, with Ontario leading production. Rainbow trout are commercially farmed in many countries throughout the world. The practice began in
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#17328546227096944-431: The bottom of rivers and streams in late winter. It is not considered a significant human health risk, but it can affect stream habitats and sources of food for fish, including rainbow trout, and make recreational activities unpleasant. Even though it is native in North America, it is considered a nuisance organism or invasive species. Enteric redmouth disease is a bacterial infection of freshwater and marine fish caused by
7056-483: The case of the westslope cutthroat trout ( O. clarki lewisi ), hybridization with introduced rainbow and Yellowstone cutthroat trout ( O. clarki bouvieri ) is threatening the westslope cutthroat trout with genomic extinction . Such introductions into the ranges of redband trout ( O. m. gairdneri , newberrii , and stonei ) have severely reduced the range of pure stocks of these subspecies, making them "species of concern" in their respective ranges. Within
7168-422: The char genus. Lake trout inhabit many of the larger lakes in North America, and live much longer than rainbow trout , which have an average maximum lifespan of seven years. Lake trout can live many decades, and can grow to more than 30 kilograms (66 lb). As salmonids, trout are coldwater fish that are usually found in cool (50–60 °F or 10–16 °C), clear streams, wetlands and lakes, although many of
7280-576: The day and larger trout crowding in during morning and evening feeding periods. Fishing for trout under the ice generally occurs in depths of 4 to 8 feet (1.2 to 2.4 m). Because trout are cold water fish, during the winter they move from up-deep to the shallows, replacing the small fish that inhabit the area during the summer. Trout in winter constantly cruise in shallow depths looking for food, usually traveling in groups, although bigger fish may travel alone and in water that's somewhat deeper, around 12 feet (3.7 m). Rainbow, Brown, and Brook trout are
7392-452: The east, Pennsylvania , North Carolina and West Virginia have farming operations. Rainbow trout farming is one of the largest finfish aquaculture industries in the U.S. They are raised inland in facilities where raceways or ponds have continuously flowing water with little pollution and a low risk of escape. The U.S. industry is noted for using best management practices . Imports constitute only about 15 percent of farmed rainbows sold in
7504-554: The effects of overfishing . Farmed trout are also sold commercially as seafood , although they are not saltwater fish . Trout meat is typically prepared the same way as salmon, often by smoking . In Mainland China , farm-raised rainbow trout from Qinghai was officially sanctioned to be labeled and sold domestically as salmon, which caused much controversy regarding food safety and consumer rights violation , as raw fish dishes or yusheng using Atlantic salmon are gaining popularity in southern China . Farmed rainbow trout
7616-405: The eggs of other rainbow trout. Rainbows also consume decomposing flesh from the carcasses of other fish. They have even been observed to have consumed hatchling snakes, such as the barred grass snake ( Natrix helvetica ). Adult steelhead in the ocean feed primarily on other fish, squid and amphipods . The native range of Oncorhynchus mykiss is in the coastal waters and tributary streams of
7728-700: The eminent zoologists like Louis Agassiz , Georges Cuvier , Charles Darwin , Thomas Huxley , Richard Owen , etc. came to be challenged. Scientific organisations tried to established practical rules to changing names, but not a uniform system. The first zoological code with priority rule was first formulated in 1842 by a committee appointed by the British Association . The committee comprising Charles Darwin, John Stevens Henslow , Leonard Jenyns , William Ogilby , John O. Westwood , John Phillips , Ralph Richardson and Hugh Edwin Strickland . The first meeting
7840-646: The first federal fish hatchery in the National Fish Hatchery System , was established on Campbell Creek, a McCloud River tributary. The McCloud River hatchery indiscriminately mixed coastal rainbow trout eggs with the eggs of local McCloud River redband trout ( O. m. stonei ) . Eggs from the McCloud hatchery were also provided to the San Leandro hatchery, thus making the origin and genetic history of hatchery-bred rainbow trout somewhat diverse and complex. In
7952-458: The fish, mykizha . The name of the genus is from the Greek ὄγκος ( ónkos ) "lump, bend, hook" and ῥύγχος ( rhúnkhos ) " snout ", in reference to the hooked jaws of males in the mating season (the " kype "). Sir John Richardson , a Scottish naturalist, named a specimen of this species Salmo gairdneri in 1836 to honor Meredith Gairdner, a Hudson's Bay Company surgeon at Fort Vancouver on
8064-448: The formal category of nomen oblitum . Similarly, if the current name for a taxon is found to have an archaic or obscure prior homonym , the current name can be declared a nomen protectum (zoology) or the older name suppressed ( nomen rejiciendum , botany). In botany and horticulture, the principle of priority applies to names at the rank of family and below. When moves are made to another genus or from one species to another,
8176-400: The foundations of modern nomenclature, he offered no recognition of prior names. The botanists who followed him were just as willing to overturn Linnaeus's names. The first sign of recognition of priority came in 1813, when A. P. de Candolle laid out some principles of good nomenclatural practice. He favoured retaining prior names, but left wide scope for overturning poor prior names. During
8288-467: The impassable barriers; a 2007 genetic study of fin samples collected from steelhead at 20 different sites both above and below passage barriers in the watershed found that although 30 million hatchery trout were stocked in the river from 1911 to 1925, the steelhead remain of native and not hatchery origin. Releases of conventionally reared hatchery steelhead pose ecological risks to wild steelhead populations. Hatchery steelhead are typically larger than
8400-612: The introduced rainbow trout disrupt local ecosystems and outcompete or prey upon indigenous fishes. Other introductions to support sport angling in waters either devoid of fish or with seriously depleted native stocks have created world-class fisheries such as in the Firehole River in Yellowstone National Park and in the Great Lakes . The International Game Fish Association recognizes the world record for rainbow trout as
8512-543: The late 19th century, and since the 1950s commercial production has grown dramatically. Worldwide, in 2007, 604,695 tonnes (666,562 short tons) of farmed rainbow trout were harvested with a value of about US$ 2.6 billion. The largest producer is Chile. In Chile and Norway, sea cage production of steelhead has expanded to supply export markets. Inland production of rainbow trout to supply domestic markets has increased in countries such as Italy, France, Germany, Denmark, and Spain. Other significant trout-producing countries include
8624-831: The length of the body. Adult fish have a broad reddish stripe along the lateral line, from gills to the tail, which is most pronounced in breeding males. The caudal fin is squarish and only mildly forked. Lake-dwelling and anadromous forms are usually more silvery in color with the reddish stripe almost completely gone. Juvenile rainbow trout display parr marks (dark vertical bars) typical of most salmonid juveniles. In some redband and golden trout forms, parr marks are typically retained into adulthood. Some coastal rainbow trout ( O. m. irideus ) and Columbia River redband trout ( O. m. gairdneri ) populations and cutbow hybrids may also display reddish or pink throat markings similar to cutthroat trout. In many regions, hatchery-bred trout can be distinguished from native trout via fin clips . Fin clipping
8736-507: The marks. These small juvenile trout are sometimes called 'fingerlings' because they are approximately the size of a human finger. In streams where rainbow trout are stocked for sport fishing, but no natural reproduction occurs, some of the stocked trout may survive and grow or "carryover" for several seasons before they are caught or perish. The oceangoing (anadromous) form, including those returning for spawning, are known as steelhead in Canada and
8848-744: The most common trout species caught through the ice. By information from International Game Fish Association (IGFA), the most outstanding records are: Salmonid populations in general have been declining due to numerous factors, including invasive species , hybridization, wildfires, and climate change. Native salmonid fish in the western and southwestern United States are threatened by non-native species that were introduced decades ago. Non-native salmonids were introduced to enrich recreational fishing; however, they quickly started outcompeting and displacing native salmonids upon their arrival. Non-native, invasive species are quick to adapt to their new environment and learn to outcompete any native species, making them
8960-410: The most vocal proponents of this position, did just that, publishing over 30000 new combinations in his Revisio Generum Plantarum . He then followed with further such publications in 1893, 1898 and 1903. His efforts, however, were so disruptive that they appear to have benefited his opponents. By the 1900s, the need for a mechanism for the conservation of names was widely accepted, and details of such
9072-485: The native Gila trout will be evacuated from streams that are threatened by nearby fires and be reintroduced after the threat is resolved. Climate change is also dwindling native salmonid populations. Global warming continually affects various cold-water fish such as trout, especially as inland waterbodies are more prone to warming than oceans. With an increase of temperature along with changes in spawning river flow, an abundance of trout species are effected negatively. In
9184-522: The native salmonids can't share genes with the non-native hatchery fish, thus, preventing further gene contamination of the native trout in New Mexico. Fire is also a factor in deteriorating Gila trout ( Oncorhynchus gilae ) populations because of the ash and soot that can enter streams following fires. The ash lowers water quality, making it more difficult for the Gila trout to survive. In some New Mexico streams,
9296-733: The nest, covering the eggs with the displaced gravel. As eggs are released by the female, a male moves alongside and deposits milt (sperm) over the eggs to fertilize them. The eggs usually hatch in about four to seven weeks although the time of hatching varies greatly with region and habitat. Newly hatched trout are called sac fry or alevin . In approximately two weeks, the yolk sac is completely consumed, and fry commence feeding mainly on zooplankton . The growth rate of rainbow trout varies with area, habitat, life history, and quality and quantity of food. As fry grow, they begin to develop "parr" marks or dark vertical bars on their sides. In this juvenile stage, immature trout are often called "parr" because of
9408-443: The ocean and migrate into their freshwater spawning tributaries at different times of the year. Two general forms exist—"summer-run steelhead" and "winter-run steelhead". Summer-run fish leave the ocean between May and October before their reproductive organs are fully mature. They mature in freshwater while en route to spawning grounds where they spawn in the spring. Summer-run fish generally spawn in longer, more inland rivers such as
9520-417: The ocean. Freshwater forms that have been introduced into the Great Lakes and migrate into tributaries to spawn are also called steelhead. Adult freshwater stream rainbow trout average between 0.5 and 2.5 kilograms (1 and 5 lb), while lake-dwelling and anadromous forms may reach 9 kg (20 lb). Coloration varies widely based on subspecies , forms, and habitat . Adult fish are distinguished by
9632-473: The past, a mere 8 °F (4.4 °C) increase was predicted to eliminate half of the native brook trout in the Southern Appalachian Mountains . Trout generally prefer streams with colder water (50–60 °F or 10–16 °C) to spawn and thrive, but raising water temperatures are altering this ecosystem and further deteriorate native populations. Principle of priority Priority
9744-560: The pathogen Yersinia ruckeri . It is primarily found in rainbow trout and other cultured salmonids . The disease is characterized by subcutaneous hemorrhaging of the mouth, fins, and eyes. It is most commonly seen in fish farms with poor water quality. Redmouth disease was first discovered in Idaho rainbow trout in the 1950s. Some fisheries are focused on removing rainbow trout in order to reestablish native trout populations. This can be done by poisoning rivers with chemicals such as antimycin or rotenone which have been declared safe in
9856-522: The range of the Kern River golden trout of Southern California, hatchery-bred rainbows introduced into the Kern River have diluted the genetic purity of the Kern River rainbow trout (O. m. gilberti) and golden trout (O. m. aguabonita) through intraspecific breeding. The Beardslee trout ( O. m. irideus var. beardsleei ) , a genetically unique lake-dwelling variety of the coastal rainbow trout that
9968-496: The sake of recreational fishing , and some of these introduced populations have even become invasive in the new habitats. While trout can be caught with a normal rod and reel , fly fishing is a distinctive lure fishing method developed for trout, and now extended to other species. Due to the high proportion of insects and small crustaceans within the trout's diet, small lures made of hand-tied hairs and threads are often used to imitate these aquatic invertebrates that
10080-434: The salmonids that M. cerebralis infects ( bull trout , cutthroat trout, and anadromous forms of rainbow trout—steelhead) are already threatened or endangered, and the parasite could worsen their population decline. The New Zealand mud snail ( Potamopyrgus antipodarum ) , once endemic to New Zealand, has spread widely and has become naturalised and an invasive species in many areas including Australia, Asia (Japan, in
10192-758: The same fashion as a salmon run . Brook trout and three other extant species of North American trout, despite the names, are actually char (or charr) , which are salmonids also closely related to trout and salmon. Trout are classified as oily fish and have been important food fish for humans . As mid-level predators , trout prey upon smaller aquatic animals including crustaceans , insects , worms , baitfish and tadpoles , and themselves in turn are also important staple prey items for many wildlifes including brown bears , otters , raccoons , birds of prey (e.g. sea eagles , ospreys , fish owls ), gulls , cormorants and kingfishers , and other large aquatic predators. Discarded remains of trout also provide
10304-794: The same reasons. As a consequence, some rainbow populations, particularly anadromous forms within their native range, have been classified as endangered , threatened or species of special concern by federal or state agencies. Rainbow trout, and subspecies thereof, are currently a U.S. Environmental Protection Agency -approved indicator species for acute freshwater toxicity testing. Many non-profit organizations have formed to protect, conserve and restore native rainbow trout and steelhead populations. Generally, in partnership with various universities, state, federal and tribal agencies, and private interests, these organizations sponsor projects to restore habitat, prevent habitat loss and promote awareness of threats to native trout populations. Trout Unlimited (TU)
10416-826: The scientific name of the rainbow trout. The previous species names irideus and gairdneri were adopted as subspecies names for the coastal rainbow and Columbia River redband trout, respectively. Anadromous forms of the coastal rainbow trout ( O. m. irideus ) or Columbia River redband trout ( O. m. gairdneri ) are commonly known as steelhead . Subspecies of Oncorhynchus mykiss are listed below as described by fisheries biologist Robert J. Behnke (2002). Resident freshwater rainbow trout adults average between 0.5 and 2.5 kg (1 and 5 lb) in riverine environments, while lake-dwelling, and anadromous forms may reach 9 kg (20 lb). Coloration varies widely between regions and subspecies. Adult freshwater forms are generally blue-green or olive green with heavy black spotting over
10528-523: The shallow gravel beds of smaller headwater creeks . The hatched fry and juvenile trout, known as alevin and parr , will stay upstream growing for years before migrating down to larger waterbodies as maturing adults . There are some anadromous species of trout, such as the steelhead (a coastal subspecies of rainbow trout ) and sea trout (the sea-run subspecies of brown trout ), that can spend up to three years of their adult lives at sea before returning to freshwater streams for spawning, in
10640-483: The skin on, the meat tends to hold together better. While trout sold commercially in Europe is often prepared and served this way, most trout sold commercially in the United States have the fish heads removed and have been fully or partially deboned and filleted. Medium to heavy-bodied white wines , such as chardonnay , sauvignon blanc , or pinot gris , are typical wine pairings for trout. In Mainland China since 2018, it
10752-527: The species have anadromous populations as well. Juvenile trout are referred to as troutlet, troutling or parr. They are distributed naturally throughout North America , northern Asia and Europe . Several species of trout were introduced to Australia and New Zealand by amateur fishing enthusiasts in the 19th century, effectively displacing and endangering several upland native fish species. The introduced species included brown trout from England and rainbow trout from California . The rainbow trout has
10864-530: The steelhead in the streams of the Santa Clara County and Monterey Bay basins are not of hatchery origin, including the Coyote Creek , Guadalupe River , Pajaro River , Permanente Creek , Stevens Creek , San Francisquito Creek , San Lorenzo River , and San Tomas Aquino Creek basins. Natural waterfalls and two major dams have isolated Russian River steelhead from freshwater rainbow trout forms above
10976-501: The surroundings, and will change as the fish moves to different habitats. Trout in, or newly returned from the sea, can look very silvery, while the same fish living in a small stream or in an alpine lake could have pronounced markings and more vivid coloration; it is also possible that in some species, this signifies that they are ready to mate. In general, trout that are about to breed have extremely intense coloration and can look like an entirely different fish outside of spawning season. It
11088-555: The transfer of one to another." In zoology, the principle of priority is defined by the International Code of Zoological Nomenclature (4th edition, 1999 ) in its article 23: The valid name of a taxon is the oldest available name applied to it, unless that name has been invalidated or another name is given precedence by any provision of the Code or by any ruling of the Commission [the International Commission on Zoological Nomenclature ]. For this reason priority applies to
11200-551: The trout prey upon. These ultralight fly lures cannot be cast adequately by conventional techniques, and a specialized heavy line (i.e. fly line) is needed to launch the lure. Understanding how moving water shapes the stream channel makes it easier to find trout. In most streams, the current creates a riffle-run-pool pattern that repeats itself over and over. A deep pool may hold a big brown trout, but rainbow trout and smaller brown trout are likely found in runs. Riffles are where fishers will find small trout, called troutlet, during
11312-853: The trout's development into an adult, a time of intense growth, the mitochondrial membrane composition and fluidity changes, which can cause defects in the electron transport chain . These defects combined with altered machinery repair and reactive oxygen species may cause more detrimental effects on the mitochondria in the fish as it matures. Rainbow trout are predators with a varied diet and will eat nearly anything they can capture. They are not as piscivorous or aggressive as brown trout or chars . Rainbow trout, including juvenile steelhead in fresh water, routinely feed on larval , pupal , and adult forms of aquatic insects (typically caddisflies , stoneflies , mayflies and aquatic diptera ). They also eat fish eggs and adult forms of terrestrial insects (typically ants, beetles, grasshoppers, and crickets) that fall into
11424-422: The types and proportions of phospholipids. With age, the heart showed more unsaturated phospholipids, which are more susceptible to peroxidation, and thus, damage. The brain mitochondria of rainbow trout show decreased levels of docosahexaenoic acid and a lower peroxidation index, suggesting a lower susceptibility to damage by oxidative stress and a different reaction to growth compared to heart mitochondria. During
11536-524: The validity of synonyms [Art. 23.3], to the relative precedence of homonyms [Arts. 53-60], the correctness or otherwise of spellings [Arts. 24, 32], and to the validity of nomenclatural acts (such as acts taken under the Principle of the First Reviser [Art. 24.2] and the fixation of name-bearing types [Arts. 68, 69, 74.1.3, 75.4]). There are exceptions: another name may be given precedence by any provision of
11648-458: The water, as well as algae. Other prey includes small fish up to one-third of their length, crayfish , shrimp, and other crustaceans . As rainbow trout grow, the proportion of fish consumed increases in most populations. Some lake-dwelling forms may become planktonic feeders. In rivers and streams populated with other salmonid species, rainbow trout eat varied fish eggs, including those of salmon, brown and cutthroat trout, mountain whitefish , and
11760-567: The wellbeing of wild salmonids in British Columbia. In 1997, a group of approximately 40 ichthyologists, biologists and naturalists from several U.S. and Mexican institutions formed a collaborative group—Truchas Mexicanas—to study the diversity of Mexican native trout , most of which are considered subspecies of O. mykiss . Rainbow trout, primarily hatchery-raised fish of the coastal rainbow trout subspecies ( O. m. irideus ) introduced into waters inhabited with cutthroat trout, will breed with cutthroats and produce fertile hybrids called cutbows. In
11872-499: The western U.S. The exact means of transmission is unknown, but it is likely that it was introduced in water transferred with live game fish and has been spread by ship ballast or contaminated recreational equipment such as wading gear. Didymosphenia geminata , commonly known as didymo or rock snot, is a species of diatom that produces nuisance growths in freshwater rivers and streams with consistently cold water temperatures. In New Zealand, invasive didymo can form large mats on
11984-519: The wild forms and can displace wild-form juveniles from optimal habitats. The dominance of hatchery steelhead for optimal microhabitats within streams may reduce wild steelhead survival as a result of reduced foraging opportunities and increased rates of predation. Rainbow trout and steelhead are highly regarded game fish among anglers . Rainbow trout are a popular target for fly fishers , and several lure fishing methods are used. The use of lures presented via spinning, casting, or trolling techniques
12096-581: Was at Darwin's house in London. The committee's report written by Strickland was implemented as the Rules of Zoological Nomenclature, and popularly known as the Stricklandian Code . It was not endorsed by all zoologists as it allowed naming, renaming and reclassifying with relative ease, as Science reported: "The worst feature of this abuse is not so much the bestowal of unknown names of well-known creatures as
12208-489: Was established on San Leandro Creek , a tributary of San Francisco Bay , in 1870, and trout production began in 1871. The hatchery was stocked with the locally native rainbow trout, and likely steelhead of the coastal rainbow trout subspecies ( O. m. irideus ) . The fish raised in this hatchery were shipped to hatcheries out of state for the first time in 1875, to Caledonia, New York , and then in 1876 to Northville, Michigan . In 1877, another California rainbow trout hatchery,
12320-613: Was listed as endangered in 2011, has been affected by habitat loss due to dams, confinement of streams in concrete channels, water pollution , groundwater pumping, urban heat island effects, and other byproducts of urbanization. Steelhead in the Kamchatka Peninsula are threatened by over-harvest, particularly from poaching and potential development, and are listed in the Red Data Book of Russia that documents rare and endangered species. Several studies have shown that almost all California coastal steelhead are of native origin, despite over
12432-526: Was originally a mild pathogen of brown trout in central Europe and other salmonids in northeast Asia, and the spread of the rainbow trout has greatly increased its impact. Having no innate immunity to M. cerebralis , rainbow trout are particularly susceptible, and can release so many spores that even more resistant species in the same area, such as Salmo trutta , can become overloaded with parasites and incur mortalities of 80 to 90 percent. Where M. cerebralis has become well-established, it has caused
12544-424: Was ruled by an industrial association that rainbow trout can be labelled and sold as salmon . Trout Trout ( pl. : trout) is a generic common name for numerous species of carnivorous freshwater ray-finned fishes belonging to the genera Oncorhynchus , Salmo and Salvelinus , all of which are members of the subfamily Salmoninae in the family Salmonidae . The word trout
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