Steelhead_Trout

From Wikipedia, the free encyclopedia Rainbow trout Rainbow trout Rainbow trout Conservation status Secure Scientific classification Kingdom: Phylum: Class: Order: Family: Genus: Species: Animalia Chordata Actinopterygii Salmoniformes Salmonidae Oncorhynchus O. mykiss Binomial name Oncorhynchus mykiss Walbaum, 1792 specimens from Kamchatka. Richardson named a specimen of this species Salmo gairdneri in 1836, and in 1855, W. P. Gibbons found a population and named it Salmo iridia, later corrected to Salmo irideus, however these names became deprecated once it was determined that Walbaum’s type description was conspecific and therefore had precedence (see e.g. Behnke, 1966).[3] More recently, DNA studies showed rainbow trout are genetically closer to Pacific salmon (Onchorhynchus species) than to brown trout (Salmo trutta) or Atlantic Salmon (Salmo salar), so the genus was changed. Unlike the species’ former name’s epithet iridia (Latin: "rainbow"), the specific epithet mykiss derives from the local Kamchatkan name ’mykizha’; all of Walbaum’s species names were based on Kamchatkan local names. Life cycle Subspecies See text The rainbow trout (Oncorhynchus mykiss) is a species of salmonid native to tributaries of the Pacific Ocean in Asia and North America as well as much of the central, western, eastern, and especially the northern portions of the United States. The ocean going (anadromous) form (including those returning for spawning) are known as steelhead, or ocean trout (Australia and United States). The species has been introduced for food or sport to at least 45 countries, and every continent except Antarctica. In some of these locations, such as Southern Europe, Australia and South America, they have had very serious negative impacts on upland native fish species, either by eating them, outcompeting them, transmitting contagious diseases, or hybridization with closely related species and subspecies that are native to western North America.[1][2] The species was originally named by Johann Julius Walbaum in 1792 based on type Illustration of a rainbow trout Like salmon, steelhead are anadromous: they return to their original hatching ground to spawn. Steelhead rejuvenate after spawning, so they may return to the oceans to start the anadromous cycle once again. The steelhead smolts (immature or young fish) usually remain in the river for about a year before heading to sea, whereas salmon typically return to the seas as smolts. Different populations of steelheads migrate upriver at different times of the year. "Summer-run steelhead" migrate between May and October, before their reproductive organs are fully 1 From Wikipedia, the free encyclopedia mature. They mature in freshwater before spawning in the spring. "Winter-run steelhead" mature fully in the ocean before migrating, between November and April, and spawn shortly after returning. Similar to Atlantic salmon, but unlike their Pacific Oncorhynchus kin, steelhead are iteroparous and may make several spawning trips between fresh and salt water. The life-span of a rainbow trout is 1 to 2.5 years. Salmon is often sold as a replacement because they taste similar. Rainbow trout Worldwide, in 2007, 604,695 tonnes of farmed salmon trout were harvested with a value of 2.589 billion USD dollars.[4] The largest producer is Chile. In Chile and Norway, the ocean cage production of steelhead has expanded to supply export markets. Inland production of rainbow trout to supply domestic markets has increased strongly in countries such as Italy, France, Germany, Denmark and Spain. Other significant producing countries include the USA, Iran, Germany and the UK.[4] There are tribal commercial fisheries for steelhead in the Puget Sound, the Washington Coast and in the Columbia River. Diet Rainbow trout are predators with a varied diet, and will eat nearly anything they can grab, in contrast to the legendary, selective image people often have of the fish’s dietary habits. Rainbows are not quite as piscivorous or aggressive as the brown trout or lake trout (char). When young, insects make up a large portion of the diet, smaller fish (up to 1/3 of their length), along with crayfish and other crustaceans make up the remainder. As they grow, though, the proportion of fish increases in most all populations. Some lake dwelling lines may become planktonic feeders. While in flowing waters populated with salmon, trout will eat salmon eggs, salmon fry, and even salmon carcasses. Although near the top of the food chain in most freshwater environments, they are prey to other freshwater predators such as pike, muskie, lake trout, and chinook salmon. Raptors, bears, and, of course, man take trout. Threats and conservation Steelhead trout have declined due to a number of human and natural causes. The U.S. National Marine Fisheries Service has a detailed description of threats. Steelhead that spawn in Southern California streams (south of Point Conception) have 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. The rainbow trout is susceptible to enteric redmouth disease. There has been considerable research conducted on redmouth disease, as its implications for rainbow trout farmers are significant. The disease does not affect humans.[5] Rainbow trout, and subspecies thereof, are currently EPA approved indicator species for acute fresh water aquatic toxicity testing. [6] Fisheries Steelhead Male ocean phase steelhead Male freshwater Steelhead phase steelhead attempting to jump some rapids Rainbow trout See also: Aquaculture of salmon Rainbow trout and steelhead are both highly desired food and sportfish. They are farmed in many countries throughout the world. Since the 1950s commercial production has grown exponentially, particularly in Europe and recently in Chile. Steelhead with clear spot pattern on fins and body As food 2 From Wikipedia, the free encyclopedia Rainbow trout • Columbia River redband trout, Oncorhynchus mykiss gairdnerii (Richardson, 1836). • Coastal rainbow trout, Oncorhynchus mykiss irideus (Gibbons, 1855). • Beardslee trout, isolated in Lake Crescent (Washington), Oncorhynchus mykiss irideus var. beardsleei (not a true subspecies, but a lake dwelling variety of Coastal rainbow trout) (Jordan, 1896). • Great Basin redband trout, Oncorhynchus mykiss newberrii (Girard, 1859). • Golden trout, Oncorhynchus mykiss aguabonita (Jordan, 1892). • Kamloops rainbow trout, Oncorhynchus mykiss kamloops (Jordan, 1892). • Kern River rainbow trout, Oncorhynchus aguabonita gilberti (Jordan, 1894). • Sacramento golden trout, Oncorhynchus aguabonita stonei (Jordan, 1894). • Little Kern golden trout, Oncorhynchus aguabonita whitei (Evermann, 1906). • Baja California rainbow trout, Nelson’s trout, or San Pedro Martir trout, Oncorhynchus mykiss nelsoni (Evermann, 1908). • Eagle Lake rainbow trout, Oncorhynchus mykiss aquilarum (Snyder, 1917). • McCloud River redband, Oncorhynchus mykiss stonei • Sheepheaven Creek redband, Oncorhynchus mykiss spp. Rainbow trout and potatoes Rainbow trout and steelhead are popular in Western cuisine and are both caught wild and farmed for food. It has tender flesh and a mild, somewhat nutty flavor. However, farmed trout and those taken from certain lakes have a pronounced earthy flavor which many people find unappealing; many shoppers therefore make it a point to ascertain the source of the fish before buying. Rainbow trout are raised in many countries throughout the world. Rainbow trout that are wild have a diet of scuds (freshwater shrimp), insects such as flies, and crayfish are the most appealing. Dark red/orange meat indicates that it is either an anadromous steelhead or a farmed Rainbow trout given a supplemental diet with a high astaxanthin content. The resulting pink flesh is marketed under monikers like Ruby Red or Carolina Red. Steelhead meat is pink like that of salmon, and is more flavorful than the light-colored meat of rainbow trout.[7] Cultivated varieties Golden rainbow trout are bred from a single mutated color variant of Oncorhynchus mykiss.[8] Golden rainbow trout are predominantly yellowish, lacking the typical green field and black spots, but retaining the diffuse red stripe.[9][8] The palomino trout is a mix of golden and common rainbow trout, resulting in an intermediate color. The golden rainbow trout should not be confused with the naturally occurring golden trout. Medicine The sperm of rainbow trout contains protamine as does that of salmon and some other species of similar fish. Protamine sulphate is an "antidote" to the anticoagulant heparin. Originally protamine was isolated from fish sperm, but is now produced in the laboratory. See also • • • • • Cutbow Fly fishing Golden trout Sport fishing Trout worms Subspecies A few populations are recognized as subspecies: • Kamchatkan rainbow trout, Oncorhynchus mykiss mykiss (Walbaum, 1792). 3 From Wikipedia, the free encyclopedia Rainbow trout Research Board of Canada. Page 189. ISBN 0-660-10239-0 References [1] Salmo marmoratus [2] Salmothymus obtusirostris salonitana [3] Robert J. Behnke. 1966. Relationships of the Far Eastern Trout, Salmo mykiss walbaum Copeia, Vol. 1966, No. 2 (Jun. 21, 1966), pp. 346-348 [4] ^ FAO: Species Fact Sheets: Oncorhynchus mykiss (Walbaum, 1792) Rome. Accessed 9 May 2009. [5] LSC - Fish Disease Leaflet 82 [6] EPA Whole Effluent Toxicity [7] Your Christmas Steelhead [8] ^ Golden Rainbow Trout. Pennsylvania Fish & Boat Commission FAQ. [9] Golden Rainbow Trout. Photo. • "Oncorhynchus mykiss". FishBase. Ed. Ranier Froese and Daniel Pauly. February 2006 version. N.p.: FishBase, 2006. • Oncorhynchus mykiss (TSN 161989). Integrated Taxonomic Information System. Retrieved on 30 January 2006. Scott and Crossman. 1985. Freshwater Fishes of Canada. Bulletin 184. Fisheries External links • Steelhead Trout – Napa County Resource Conservation District • Association of Northwest Steelheaders • Fish-On! - Full Rainbow Trout Chapter at TheFishingNetwork.com • Rainbow trout page from the Alaska Department of Fish and Game • Rainbow trout information from Northern State University • Australian Aquaculture Portal • Fishbase.org article on Oncorhynchus mykiss, Rainbow trout • Kenai River, Alaska Rainbow Trout Fact Page • ZipcodeZoo fact page • Season/Timing information for Steelhead in the Great Lakes region • [1] Huge Alaska Rainbow Trout Photo Page Retrieved from "http://en.wikipedia.org/wiki/Rainbow_trout" Categories: Oncorhynchus, Cold water fish, Introduced freshwater fish of New Zealand, Washington (U.S. state) culture, Fauna of the United States, Invasive animal species, Fly fishing target species, Fish of the Pacific, Fishes of Michigan, Fish of the Great Lakes (US) This page was last modified on 23 May 2009, at 17:35 (UTC). 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