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86-558: Lago Argentino lies within Los Glaciares National Park , in a landscape accented by numerous glaciers , and the lakes of the area are fed by the glacial meltwater of several rivers. For example, the waters of Lake Viedma are fed by the La Leona River , and many other, smaller mountain streams. Lago Argentino's drainage basin amounts to more than 17,000 km (6,564 sq mi). Water from Lake Argentino flows into

172-659: A World Heritage Site by UNESCO . The park's name refers to the giant ice cap in the Andes , the largest outside of Antarctica , Greenland and Iceland , feeding 47 large glaciers , of which 13 flow towards the Pacific Ocean . In other parts of the world, glaciers start at a height of at least 2,500 m (8,200 ft) above mean sea level , but due to the size of the ice cap, these glaciers begin at only 1,500 m (4,900 ft), sliding down to 200 m (660 ft). Los Glaciares borders Torres del Paine National Park to

258-399: 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

344-747: 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

430-418: 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

516-623: 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

602-598: 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

688-437: 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

774-749: 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

860-641: 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

946-682: 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

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1032-467: Is a federal protected area in Santa Cruz Province , Argentina . The park covers an area of 726,927 ha (7,269.27 km ; 2,806.68 sq mi), making it the largest national park in the country. Established on 11 May 1937, it hosts a representative sample of Magellanic subpolar forest and west Patagonian steppe biodiversity in good state of conservation. In 1981, it was declared

1118-531: 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

1204-526: Is an accepted version of this page 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

1290-558: 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 ,

1376-448: 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 the marks. These small juvenile trout are sometimes called 'fingerlings' because they are approximately

1462-462: 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

1548-523: 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

1634-503: Is home to numerous living organisms; as of 2024, the biodiversity database iNaturalist lists nearly 500 recorded plant and almost 400 animal species as being found in the area, as well as nearly 100 types of fungi and lichen . Birds Around 150 species of birds have been documented in and around the lake. Many are endemic to the region, such as the roughly 50-60 species of wading birds and waterfowl ; iconic amphibious species, like Andean and Chilean flamingos , as well as

1720-483: 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

1806-548: 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

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1892-559: 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

1978-592: The Atlantic Ocean through the Santa Cruz River . The glaciers, the nearby town of El Calafate , and the lake itself are all important tourist destinations, with many unique hostels, hotels and other amenities catering to the outdoors located in the region. The lake, in particular, is appreciated for fishing . Perch , common galaxias (" puyen grande "), lake trout and rainbow trout —in both anadromous and potamodromous forms—are all found. Lago Argentino

2064-600: 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

2150-610: 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

2236-581: 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

2322-496: 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

2408-694: 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

2494-518: 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

2580-414: The black-headed duck , black-necked swan , cinnamon teal , crested duck , Coscoroba swan , kelp goose , silver teal , torrent duck and many others can be found here, as well as varied species of coot , cormorant , dotterel , gallinule , godwit , grebe , gull , knot , lapwing , oystercatcher , phalarope , plover , sandpiper , snipe , stilt , tern and yellowlegs . Other birds include

2666-675: 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

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2752-537: 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

2838-493: 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

2924-684: The Atlantic. Between the two halves is a non-touristic zone without lakes called Zona Centro . The northern half consists of part of Viedma Lake , the Viedma Glacier and a few minor glaciers, and a number of mountains very popular among fans of climbing and trekking, including Mount Fitz Roy and Cerro Torre . The southern part has, as well as a number of smaller ones, the major glaciers which flow into Lake Argentino: Perito Moreno Glacier , Upsala Glacier , and Spegazzini Glacier . Typical excursion boats travel between icebergs to visit Onelli Bay , and

3010-669: 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

3096-399: 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

3182-559: 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

3268-789: 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

3354-504: 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

3440-627: 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

3526-585: 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

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3612-511: 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

3698-488: 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

3784-433: 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

3870-485: 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

3956-456: 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

4042-407: 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

4128-402: The famous Andean condor (the largest New World vulture ), Austral parakeet , Austral pygmy-owl , cinereous harrier , crested caracara , the flightless Darwin's rhea (the largest bird in the area), lesser horned owl , Magellanic woodpecker , and the short-eared owl . Fish Puyen ( Galaxias maculatus ) and perca ( Percichthys ), are two registered species of fish that live in

4214-648: 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

4300-459: 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

4386-468: 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

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4472-579: 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

4558-542: The lake include Alsodes coppingeri , the Eden Harbour toad ( Nannophryne variegata ), the large four-eyed frog ( Pleurodema bufoninum ), Nibaldo's wood frog ( Batrachyla nibaldoi ), and the Puerto Eden frog ( Chaltenobatrachus grandisonae ). Argentino Lake has a cold desert climate (Köppen BWk ). Los Glaciares National Park Los Glaciares National Park ( Spanish : Parque Nacional Los Glaciares )

4644-550: The lake. Also present are introduced and non-native brown trout ( Salmo trutta ), chinook salmon ( Oncorhynchus tshawytscha ), lake trout ( Salvelinus namaycush ) and rainbow trout ( O . mykiss ). Reptiles and Amphibians Of the roughly 10-15 reptile species recorded in the vicinity of Lago Argentino, the majority of them are lizards ( Squamata ) of the generas Diplolaemus and Liolaemus , including several species of tree "iguanas", smooth-headed and smooth-throated lizards. Anurans ( frogs and toads ) that inhabit

4730-546: 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

4816-750: The latter of which has suffered from the invasion of the cattle industry and are endangered . The guanaco, while not endangered, has had a dramatic decline in historic population due to large scale grazing of livestock throughout much of Patagonia. There are over 100 species of birds in the area ( condors , eagles , and others). Between the ice and the Patagonian steppe there is a fertile area of Magellanic subpolar forests composed mainly of lengas and guindos , but also ñires . Within these more hospitable areas also live huemul deer and torrent duck . Los Glaciares National Park faces many issues around tourism, overgrazing , forest fires and more. There are areas of

4902-835: 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

4988-417: 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

5074-423: The otherwise inaccessible Spegazzini and Upsala. Perito Moreno is reachable by land. The park has a cool and moist temperate climate. Mean temperatures range from 0.6 °C (33.1 °F) in winter to 13.4 °C (56.1 °F) in summer although at higher altitudes, the mean annual temperature can be around −3 °C (26.6 °F). The park receives an average annual rainfall of 500 mm (20 in) in

5160-420: The park where overgrazing is quite a problem and contains many alien/ invasive and feral species such as cattle, European hares and certain types of trout. Forest fires have had a strong impact on the site and degraded and destroyed parts of it as well. Los Glaciares is a major attraction for international tourists. Starting points of tours are the city of El Calafate at the shore of Lake Argentino but outside

5246-525: The park, where the park's administration has its headquarters, and El Chaltén village in the northern part of the park, at the foot of the Fitz Roy. Other touristic points in the park include Lago del Desierto and Lago Roca . It was also used as one of the filming locations for "Return of the Ice", the second episode of the speculative science documentary series The Future is Wild . Rainbow trout This

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5332-561: 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

5418-525: 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

5504-471: The river for one to three years before smolting and migrating to sea. Individual steelhead populations leave 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

5590-437: 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

5676-796: 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)

5762-479: 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

5848-829: 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

5934-526: 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 the U.S. In Tasmania they are commercially propagated in sea cages and are known as ocean trout , although they are

6020-485: 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

6106-575: The south in Chilean territory. Los Glaciares, of which 30% is covered by ice, can be divided in two parts, each corresponding with one of the two elongated big lakes partially contained by the park. Lake Argentino , 1,466 km (566 sq mi) and the largest in Argentina, is in the south, while Lake Viedma , 1,100 km (420 sq mi), is in the north. Both lakes feed the Santa Cruz River that flows down to lower part Puerto Santa Cruz on

6192-909: The spring. Summer-run fish generally spawn in longer, more inland rivers such as 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,

6278-531: 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

6364-853: 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

6450-422: 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

6536-409: The upstream edge of 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

6622-459: 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

6708-570: 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

6794-512: The west and 900 mm (35 in) in the east which is evenly distributed throughout the year. Snowfall is common during the colder months. The mountains hold most of the humidity from the Pacific Ocean , letting through only the ice coldness (annual average of 7.5 °C (45.5 °F)) and creating the arid Patagonian steppe on the Argentine side of the range. This area is habitat for rheas , guanaco , cougar , and South American gray fox ,

6880-502: 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

6966-520: 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

7052-489: The world record for rainbow trout as 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

7138-400: Was also the name of the airport that served the area until 2000. This airport is currently closed, and its runway was incorporated into the city's road system. It has since been replaced by Comandante Armando Tola International Airport , which serves the town of El Calafate and Lago Argentino with many national and international flights each day. Lago Argentino, and its surrounding terrain,

7224-489: 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,

7310-615: 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

7396-526: 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

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