Common carp
The common carp or European carp is a widespread freshwater fish of eutrophic waters in lakes and large rivers in Europe and Asia. The native wild populations are considered vulnerable to extinction by the International Union for Conservation of Nature, but the species has been domesticated and introduced into environments worldwide, is considered a destructive invasive species, being included in the list of the world's 100 worst invasive species, it gives its name to the carp family Cyprinidae. The two subspecies are: C. c. carpio is native to much of Europe. C. c. yilmaz is from Anatolian Turkey. A third subspecies, C. c. haematopterus native to eastern Asia, was recognized in the past, but recent authorities treat it as a separate species under the name C. rubrofuscus. The common carp and various Asian relatives in the pure forms can be separated by meristics and differ in genetics, but they are able to interbreed. Common carp can interbreed with the common goldfish; the common carp is native to Europe and Asia, has been introduced to every part of the world except the poles.
They are the third most introduced species worldwide, their history as a farmed fish dates back to Roman times. Carp are used as food in many areas, but are regarded as a pest in several regions due to their ability to out-compete native fish stocks; the original common carp was found in the inland delta of the Danube River about 2000 years ago, was torpedo-shaped and golden-yellow in colour. It had two pairs of a mesh-like scale pattern. Although this fish was kept as an exploited captive, it was maintained in large, specially built ponds by the Romans in south-central Europe; as aquaculture became a profitable branch of agriculture, efforts were made to farm the animals, the culture systems soon included spawning and growing ponds. The common carp's native range extends to the Black Sea, Caspian Sea and Aral Sea. Both European and Asian subspecies have been domesticated. In Europe, domestication of carp as food fish was spread by monks between the 13th and 16th centuries; the wild forms of carp had reached the delta of the Rhine in the 12th century with some human help.
Variants that have arisen with domestication include the mirror carp, with large, mirror-like scales, the leather carp, the scaled carp. Koi carp is a domesticated ornamental variety that originated in the Niigata region of Japan in the 1820s, but its parent species are the East Asian carp C. rubrofuscus. Wild common carp are slimmer than domesticated forms, with body length about four times body height, red flesh, a forward-protruding mouth. Common carp can grow to large sizes if given adequate space and nutrients, their average growth rate by weight is about half the growth rate of domesticated carp They do not reach the lengths and weights of domesticated carp, which can grow to a maximum length of 120 centimetres, a maximum weight of over 40 kilograms, an oldest recorded age of 38 years. The largest recorded carp, caught by an angler in January 2010 at Lac de curtons near Bordeaux, weighed 42.6 kilograms. The largest recorded carp, caught by British angler, Colin Smith, in 2013 at Etang La Saussaie Fishery, weighed 45.59 kilograms.
The average size of the common carp is around 40 -- 2 -- 14 kg. Although tolerant of most conditions, common carp prefer large bodies of slow or standing water and soft, vegetative sediments; as schooling fish, they prefer to be in groups of five or more. They live in temperate climates in fresh or brackish water with a pH of 6.5–9.0 and salinity up to about 0.5%, temperatures of 3 to 35 °C. The ideal temperature is 23 to 30 °C, with spawning beginning at 17 to 18 °C. Carp are able to tolerate water with low oxygen levels, by gulping air at the surface. Common carp are omnivorous, they can eat a herbivorous diet of aquatic plants, but prefer to scavenge the bottom for insects, crustaceans and benthic worms. An egg-layer, a typical adult female can lay 300,000 eggs in a single spawn. Although carp spawn in the spring, in response to rising water temperatures and rainfall, carp can spawn multiple times in a season. In commercial operations, spawning is stimulated using a process called hypophysation, where lyophilized pituitary extract is injected into the fish.
The pituitary extract contains gonadotropic hormones which stimulate gonad maturation and sex steroid production promoting reproduction. A single carp can lay over a million eggs in a year, yet their population remains the same, so the eggs and young perish in vast numbers. Eggs and fry fall victim to bacteria and the vast array of tiny predators in the pond environment. Carp which survive to juvenile are preyed upon by other fish such as the northern pike and largemouth bass, a number of birds and mammals. Common carp have been introduced to some 59 countries. In abs
Rainbow trout
The rainbow trout is a trout and species of salmonid native to cold-water tributaries of the Pacific Ocean in Asia and North America. The steelhead is an anadromous form of the coastal rainbow trout or Columbia River redband trout that returns to fresh water to spawn after living two to three years in the ocean. Freshwater forms that have been introduced into the Great Lakes and migrate into tributaries to spawn are called steelhead. Adult freshwater stream rainbow trout average between 1 and 5 lb, while lake-dwelling and anadromous forms may reach 20 lb. Coloration varies based on subspecies and habitat. Adult fish are distinguished by a broad reddish stripe along the lateral line, from gills to the tail, most vivid in breeding males. Wild-caught and hatchery-reared forms of this 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, 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, or hybridizing with related species and subspecies, thus reducing genetic purity. The rainbow trout is included in the list of the top 100 globally invasive species. Nonetheless, other introductions into waters devoid of any fish species or with 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 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 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, was derived from the local Kamchatkan name used for the fish, mykizha.
The name of the genus is from the Greek onkos and rynchos, in reference to the hooked jaws of males in the mating season. 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 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 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 the Pacific basin were genetically closer to Pacific salmon than to the Salmos – brown trout or Atlantic salmon of the Atlantic basin. Thus, in 1989, taxonomic authorities moved the rainbow and other Pacific basin trout into the genus Oncorhynchus. Walbaum's name had precedence, so the species name Oncorhynchus mykiss became 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 or redband trout are known as steelhead. Subspecies of Oncorhynchus mykiss are listed below as described by fisheries biologist Robert J. Behnke. Resident freshwater rainbow trout adults average between 1 and 5 lb in riverine environments, while lake-dwelling and anadromous forms may reach 20 lb. Coloration varies between regions and subspecies. Adult freshwater forms are blue-green or olive green with heavy black spotting over the length of the body. Adult fish have a broad reddish stripe along the lateral line, from gills to the tail, most pronounced in breeding males; the caudal fin is only mildly forked. Lake-dwelling and anadromous forms are more silvery in color with the reddish stripe completely gone. Juvenile rainbow trout display parr marks typical of most salmonid juveniles. In some redband and golden trout forms parr marks are retained into adulthood.
Some coastal rainbow trout and Columbia River redband trout populations and cutbow hybrids may 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 the adipose fin is a management tool used to identify hatchery-reared fish. Rainbow trout, including steelhead forms spawn in early to late spring when water temperatures reach at least 42 to 44 °F; the maximum recorded lifespan for a rainbow trout is 11 years. Freshwater resident rainbow trout inhabit and spawn in small to moderately large, well oxygenated, shallow rivers with gravel bottoms, they are native to 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 found in moderately deep, cool lakes with
Green River, Wyoming
Green River is a city in and the county seat of Sweetwater County, United States, in the southwestern part of the state. The population was 12,515 at the 2010 census. Green River was incorporated in 1868 in what was the Dakota Territory, on the banks of the Green River; the city was the starting point from which John Wesley Powell started his famous expeditions of the Green River, the Colorado River, the Grand Canyon in the late 1800s. The town of Green River was supposed to be the site of a division point for the Union Pacific Railroad, but when the railroad reached the point, officials were surprised to find that the large town had been established there requiring costly negotiations for railroad land, they moved the division point 12 miles west, creating the town of Bryan, on the Blacks Fork of the Green River. At the time of its incorporation in 1868, Green River had about 2000 residents and permanent adobe buildings were being built. However, when the division point of the railroad was moved west, the settlement shrank to a mere 101 residents.
Just when Green River was on the verge of becoming a ghost town, Blacks Fork dried up during a drought and the railroad was forced to move the division point back to Green River to ensure adequate water for its steam locomotives. The town was re-incorporated under the new laws of Wyoming on May 5, 1891, while Bryan became the ghost town; the city is known as being one of the first in the United States to ban door-to-door solicitation, under the Green River Ordinance. According to the United States Census Bureau, the city has a total area of 14.02 square miles, of which, 13.73 square miles is land and 0.29 square miles is water. Green River experiences a semi-arid climate with long, dry winters and hot wetter summers; as of the census of 2010, there were 12,515 people, 4,642 households, 3,406 families residing in the city. The population density was 911.5 inhabitants per square mile. There were 5,002 housing units at an average density of 364.3 per square mile. The racial makeup of the city was 92.1% White, 0.4% African American, 0.8% Native American, 0.5% Asian, 0.1% Pacific Islander, 4.1% from other races, 2.0% from two or more races.
Hispanic or Latino of any race were 13.4% of the population. There were 4,642 households of which 39.0% had children under the age of 18 living with them, 59.4% were married couples living together, 7.9% had a female householder with no husband present, 6.0% had a male householder with no wife present, 26.6% were non-families. 21.6% of all households were made up of individuals and 5.7% had someone living alone, 65 years of age or older. The average household size was 2.68 and the average family size was 3.12. The median age in the city was 33.9 years. 28.4% of residents were under the age of 18. The gender makeup of the city was 51.6% male and 48.4% female. As of the census of 2000, there were 11,808 people, 4,177 households, 3,212 families residing in the city; the population density was 861.5 people per square mile. There were 4,426 housing units at an average density of 322.9 per square mile. The racial makeup of the city was 92.13% White, 0.27% African American, 1.36% Native American, 0.32% Asian, 0.06% Pacific Islander, 4.23% from other races, 1.63% from two or more races.
Hispanic or Latino of any race were 10.21% of the population. There were 4,177 households out of which 42.5% had children under the age of 18 living with them, 64.4% were married couples living together, 8.4% had a female householder with no husband present, 23.1% were non-families. 19.3% of all households were made up of individuals and 6.0% had someone living alone, 65 years of age or older. The average household size was 2.80 and the average family size was 3.22. In the city, the population was spread out with 31.1% under the age of 18, 8.8% from 18 to 24, 28.9% from 25 to 44, 24.8% from 45 to 64, 6.5% who were 65 years of age or older. The median age was 34 years. For every 100 females, there were 102.8 males. For every 100 females age 18 and over, there were 100.7 males. The median income for a household in the city was $53,164, the median income for a family was $59,100. Males had a median income of $51,418 versus $24,306 for females; the per capita income for the city was $20,398. About 3.1% of families and 4.5% of the population were below the poverty line, including 6.0% of those under age 18 and 5.3% of those age 65 or over.
The Green River Basin contains the world's largest known deposit of trona ore. Soda ash mining from trona veins 900 and 1,600 feet deep is a major industrial activity in the area, employing over 2000 persons at five mines; the mining operation is less expensive for production of soda ash in the United States than the synthetic Solvay process, which predominates in the rest of the world. The trona in Sweetwater County was created by an ancient body of water known as Lake Gosiute. Over time, the lake shrank. With the loss of outflows alkaline water began to evaporate, depositing the beds of trona; the four mines are run by these companies: Tata Chemicals Ltd. Tronox Limited Ciner Resources LP Solvay Chemicals Inc; the Green River Basin has large oil shale and natural gas reserves, which remain untouched due to the high cost of extracting the oil from the hard shale formations. However, an increase in oil prices in 2008 and a national desire to become more energy independent led to an increase in well drilling and oil exploration.
Expansion growth from Halliburton and Exxon, as well as other oil companies, creat
Flaming Gorge Dam
Flaming Gorge Dam is a concrete thin-arch dam on the Green River, a major tributary of the Colorado River, in northern Utah in the United States. Flaming Gorge Dam forms the Flaming Gorge Reservoir, which extends 91 miles into southern Wyoming, submerging four distinct gorges of the Green River; the dam is a major component of the Colorado River Storage Project, which stores and distributes upper Colorado River Basin water. The dam takes its name from a nearby section of the Green River canyon, named by John Wesley Powell in 1869, it was built by the U. S. Bureau of Reclamation between 1958 and 1964; the dam is 502 feet high and 1,285 feet long, its reservoir has a capacity of more than 3.7 million acre feet, or about twice the annual flow of the upper Green. Operated to provide long-term storage for downstream water-rights commitments, the dam is a major source of hydroelectricity and is the main flood-control facility for the Green River system; the dam and reservoir have fragmented the upper Green River, blocking fish migration and impacting many native species.
Water released from the dam is cold and clear, as compared to the river's natural warm and silty flow, further changing the local riverine ecology. However, the cold water from Flaming Gorge has transformed about 28 miles of the Green into a "Blue Ribbon Trout Fishery"; the Flaming Gorge Reservoir situated in Flaming Gorge National Recreation Area, is considered one of Utah and Wyoming's greatest fisheries. Contrary to its namesake, Flaming Gorge, the dam lies in steep, rapid-strewn Red Canyon in northeastern Utah, close to where the Green River cuts through the Uinta Mountains; the canyon, for which the dam is named, is buried under the reservoir 20 miles upstream. Red Canyon is the narrowest and deepest of the four on the Green in the area which made it the best site for the building of a dam. Flaming Gorge, on the other hand, was named by John Wesley Powell on his 1869 expedition down the Green and Colorado rivers for the "brilliant, flaming red of its rocks."Flaming Gorge Dam is one of six that make up the Colorado River Storage Project, a massive system of reservoirs created in the upper Colorado River Basin by the Bureau of Reclamation from the 1950s to the 1970s.
The project itself was the indirect result of a system of agreements signed by the seven U. S. states and two Mexican provinces in the early 20th century dividing the flow of the Colorado River among them. Among the terms stated in the 1922 Colorado River Compact reserved 7.5 million acre feet for the Upper Basin states of Wyoming, Colorado and New Mexico and an equal amount for the Lower Basin states of Arizona and California. Due to the Colorado's high year-to-year variations in flow, the upper basin could not fulfill the lower basin's allotments in dry years, much water was wasted during wet years because of the lack of a means to impound it. Well before the CRSP's inception in 1956, the Bureau had begun to look for suitable reservoir sites along the upper Colorado and tributaries such as the Green, San Juan and Gunnison Rivers. One of the earlier proposals was called Echo Park Dam, at the confluence of the Green and Yampa Rivers within the Dinosaur National Monument in northwestern Colorado.
The Sierra Club, led by David Brower, rallied against the proposal in the media and in the courts. When the Bureau backed down from the Echo Park proposal, it was seen as one of the environmentalism movement's early victories – but it came with a compromise. A dam would still be built on the Green River, just 50 miles upstream near a brilliant red-rock canyon called Flaming Gorge. A common misconception is that the building of the controversial Glen Canyon Dam was part of this "compromise for Echo Park", but in reality the Bureau had always planned to build a dam at Glen Canyon regardless of the outcome of the Echo Park debate; the building of Flaming Gorge Dam started just a few months after the CRSP was approved in Congress, when President Dwight D. Eisenhower pressed a button on his desk in the White House and set off the first blast in Red Canyon. Site preparations and geologic inspections continued as Dutch John, the company town that provided housing for the workers, was completed just northeast of the dam site by 1958.
More than 3000 people would inhabit Dutch John at the peak of construction. The main contract for dam construction was awarded to Arch Dam Constructors, a conglomerate of Peter Kiewit Sons, Morrison-Knudsen Company, Mid-Valley Utility Constructors Inc. and Coker Construction Company. Actual construction at the dam site did not begin until late 1958, when work began on the diversion tunnel that would send the Green River around the dam site in order to clear it. By April 1959, excavation of the diversion tunnel had been completed and concrete lining was finished on August 17. Work on a pair of earthen cofferdams above and below the dam site commenced when the tunnel was ready and the river was channeled around the dam site on November 19 with the completion of the upper cofferdam. Keyway excavations for the dam on the right abutment and construction of the spillway inlet works in the left abutment was begun in September, all preliminary canyon wall structures were complete by early 1960; the lower cofferdam was finished in February, allowing workers to pump water out of the space between the two barriers.
The silt and sediment that comprised the riverbed had to be removed in order to reach solid rock where foundations could be drilled. Flaming Gorge was built in block-shaped stages of concrete called "forms"; the f
Canyon
A canyon or gorge is a deep cleft between escarpments or cliffs resulting from weathering and the erosive activity of a river over geologic timescales. Rivers have a natural tendency to cut through underlying surfaces wearing away rock layers as sediments are removed downstream. A river bed will reach a baseline elevation, the same elevation as the body of water into which the river drains; the processes of weathering and erosion will form canyons when the river's headwaters and estuary are at different elevations through regions where softer rock layers are intermingled with harder layers more resistant to weathering. A canyon may refer to a rift between two mountain peaks, such as those in ranges including the Rocky Mountains, the Alps, the Himalayas or the Andes. A river or stream and erosion carve out such splits between mountains. Examples of mountain-type canyons are Provo Canyon in Utah or Yosemite Valley in California's Sierra Nevada. Canyons within mountains, or gorges that have an opening on only one side, are called box canyons.
Slot canyons are narrow canyons that have smooth walls. Steep-sided valleys in the seabed of the continental slope are referred to as submarine canyons. Unlike canyons on land, submarine canyons are thought to be formed by turbidity currents and landslides; the word canyon is Spanish in origin, with the same meaning. The word canyon is used in North America while the words gorge and ravine are used in Europe and Oceania, though gorge and ravine are used in some parts of North America. In the United States, place names use canyon in the southwest and gorge in the northeast, with the rest of the country graduating between these two according to geography. In Canada, a gorge is narrow while a ravine is more open and wooded; the military-derived word defile is used in the United Kingdom. Most canyons were formed by a process of long-time erosion from table-land level; the cliffs form because harder rock strata that are resistant to erosion and weathering remain exposed on the valley walls. Canyons are much more common in arid than in wet areas because physical weathering has a more localized effect in arid zones.
The wind and water from the river combine to erode and cut away less resistant materials such as shales. The freezing and expansion of water serves to help form canyons. Water seeps into cracks between the rocks and freezes, pushing the rocks apart and causing large chunks to break off the canyon walls, in a process known as frost wedging. Canyon walls are formed of resistant sandstones or granite. Sometimes large rivers run through canyons as the result of gradual geological uplift; these are called entrenched rivers, because they are unable to alter their course. In the United States, the Colorado River in the Southwest and the Snake River in the Northwest are two examples of tectonic uplift. Canyons form in areas of limestone rock; as limestone is soluble to a certain extent, cave systems form in the rock. When these collapse, a canyon is left, as in the Mendip Hills in Somerset and Yorkshire Dales in Yorkshire, England. A box canyon is a small canyon, shorter and narrower than a river canyon, with steep walls on three sides, allowing access and egress only through the mouth of the canyon.
Box canyons were used in the western United States as convenient corrals, with their entrances fenced. The definition of "largest canyon" is imprecise, because a canyon can be large by its depth, its length, or the total area of the canyon system; the inaccessibility of the major canyons in the Himalaya contributes to their not being regarded as candidates for the biggest canyon. The definition of "deepest canyon" is imprecise if one includes mountain canyons as well as canyons cut through flat plateaus; the Yarlung Tsangpo Grand Canyon, along the Yarlung Tsangpo River in Tibet, is regarded by some as the deepest canyon in the world at 5,500 m. It is longer than the Grand Canyon in the United States. Others consider the Kali Gandaki Gorge in midwest Nepal to be the deepest canyon, with a 6400 m difference between the level of the river and the peaks surrounding it. Vying for deepest canyon in the Americas are the Cotahuasi Canyon and Colca Canyon, in southern Peru. Both have been measured at over 3500 m deep.
The Grand Canyon of northern Arizona in the United States, with an average depth of 1,600 m and a volume of 4.17 trillion cubic metres, is one of the world's largest canyons. It was among the 28 finalists of the New7Wonders of Nature worldwide poll; the largest canyon in Africa is the Fish River Canyon in Namibia. In August 2013, the discovery of Greenland's Grand Canyon was reported, based on the analysis of data from Operation IceBridge, it is located under an ice sheet. At 750 kilometres long, it is believed to be the longest canyon in the world; the Capertee Valley in Australia is reported as being the second largest canyon in the world. Some canyons have notable cultural significance. Evidence of early humanoids has been discovered in Africa's Olduvai Gorge. In the southwestern United States, canyons are important archeologically because of the many cliff-dwellings built in such areas by the ancient Pueblo people who were their first inhabitants; the following list contains only the most notable canyons of the world, arranged by continent and country.
Fish River Canyon Blyde Riv
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