Oncorhynchus туқымдас балықтар туралы

Genus of fishes

Oncorhynchus is a genus of ray finned fish in the subfamily Salmoninae of the family Salmonidae, native to coldwater tributaries of the North Pacific basin. The genus contains twelve extant species, namely six species of Pacific salmon and six species of Pacific trout, all of which are migratory (either anadromous or potamodromous) mid level predatory fish that display natal homing and semelparity. The name of the genus is derived from the Greek ὄγκος (ónkos, 'lump, bend') + ῥύγχος (rhúnkhos, 'snout'), in reference to the hooked secondary sexual characteristic — known as the kype — that the males develop on the lower jaw tip during mating season.

Salmon and trout within Onchorhynchus are native to the tributaries of the North Pacific Ocean, with their native ranges extend from the Bering Sea coasts southwards to as far as Taiwan in the west and Mexico in the east, although most of them are distributed in high latitude cold waters from the Russian Far East to the Pacific Northwest. In North America, some subspecies of cutthroat trout (O. clarkii) have become landlocked populations native to endorheic waters in the Rocky Mountains and the Great Basin, while others have crossed the Continental Divide to inhabit the Rio Grande and western tributaries of the Mississippi River, both of which drain into the Gulf of Mexico instead of the Pacific Ocean. Several species of Oncorhynchus, such as the rainbow trout (O. mykiss) and Chinook salmon (O. tshawytscha), have been widely introduced into non native waters around the globe, establishing self sustaining wild populations. The six Pacific salmons of Oncorhynchus are anadromous (migratory) and semelparous (die after spawning). Migration can be affected by parasites. Infected individuals can become weak and probably have shortened lifespans. Infection with parasites creates an effect known as culling whereby fish that are infected are less likely to complete the migration. Anadromous forms of Oncorhynchus mykiss known as steelhead are iteroparous. The coastal cutthroat trout (Oncorhynchus clarkii clarkii) is considered semi anadromous, as it spends some time in the ocean, usually much closer to its native stream than its fully anadromous relatives.

Several Late Miocene (about 7 million years ago (Mya)) trout like fossils in Idaho, in the Clarkia Lake beds, appear to be of Oncorhynchus. The presence of these species so far inland established Oncorhynchus was not only present in the Pacific drainages before the beginning of the Pliocene (5–6 Mya), but also that rainbow and cutthroat trout, and Pacific salmon lineages had diverged before the beginning of the Pliocene. Consequently, the split between Oncorhynchus and Salmo (Atlantic salmon) must have occurred well before the Pliocene. Suggested dates have gone back as far as the Early Miocene (about 20 Mya). Speciation among Oncorhynchus has been examined for decades, and a family "tree" is not yet completely developed for the Pacific salmonids. Mitochondrial DNA (mtDNA) research has been completed on a variety of Pacific trout and salmonid species, but the results do not necessarily agree with fossil research, or molecular research. Chum, pink and sockeye salmon lineages are generally agreed to have diverged in the sequence after other species. Montgomery (2000) discusses the pattern of the fossil record as compared to tectonic shifts in the plates of the Pacific Northwest of America. The (potential) divergence in Oncorhynchus lineages appear to follow the uprising of the Pacific Rim. The climatic and habitat changes that would follow such a geologic event are discussed, in the context of potential stressors leading to adaptation and speciation. One interesting case involving speciation with salmon is that of the kokanee salmon (landlocked sockeye salmon). Kokanee sockeye evolve differently from anadromous sockeye—they reach the level of "biological species". Biological species—as opposed to morphological species—are defined by the capacity to maintain themselves in sympatry as independent genetic entities. This definition can be vexing because it apparently applies only to sympatry, and this limitation makes the definition difficult to apply. Examples in Washington State, Canada, and elsewhere have two populations living in the same lake, but spawning in different substrates at different times, and eating different food sources. There is no pressure to compete or interbreed (two responses when resources are short). These types of kokanee salmon show the principal attributes of a biological species: they are reproductively isolated and show strong resources partitioning.

A general decline in overall Pacific salmon populations began in the mid 19th century. As the result of western expansion and development in the U. S., experts estimate salmon populations in the Columbia River basin had been reduced to less than 20% of their pre 1850 levels by 1933. In 2008, Lackey estimated that Pacific salmon stocks in the Pacific Northwest were less than 10% of their pre 1850 numbers. Many of the remaining salmon runs are dominated by hatchery raised salmon, not wild salmon.]] [[File:Pacific salmon size declines could result in negative consequences for ecosystems and people. webp|thumb|200px|"Salmon body size declines over the past 30 years have negative consequences for a fecundity, b nutrient transport, c commercial fishery value, and d rural food security". The mean body length of Oncorhynchus species decreased by 2 8% between 1990 and 2010. fishing practices, and increased competition in the ocean. The problem is that hatcheries can never truly replicate the environment of wild salmon, an issue which often results in physiological and behavioral differences between wild salmon and those reared in hatcheries. These differences are often the product of genetic changes associated with inbreeding, artificial selection, and natural selection, as well as different environmental pressures acting on hatchery fish than wild populations. Due to the size selective nature of fishing favoring larger fish, a reduction in average size of the adult salmon has been observed over time. The smaller salmon make a greater proportion of the remaining individuals continuing the population, and problems arise when these hatchery reared fish are introduced into the wild populations. Unlike wild salmon, larger salmon are selected for in hatcheries and are typically much larger than wild salmon. The result is that hatchery produced salmon tend to out compete wild salmon for space, food, and other resources. Some salmon species in hatcheries exhibit predatory behavior toward wild salmon because they grow to be much larger. Regardless of whether predation is observed, natural social interactions are disturbed by the release of large numbers of hatchery reared salmon where wild populations are low because salmon in hatcheries naturally have a higher propensity towards aggressive behavior. Overall, natural salmon populations are put at risk when hatchery reared salmon populations are introduced due to competition for resources, predation by larger individuals, and negative social interactions that upset the natural order observed in wild salmon populations. As a result, wild salmon populations are steadily dropping as the pressure to continue breeding salmon in hatcheries increases. Conservation efforts that work to place limitations on hatcheries to increase the wild salmon populations are hindered by financial pressures because hatcheries effectively support many states economically by accounting for over 70% of the salmon harvested for recreational and commercial purposes.

Pacific salmon are harvested throughout the world as a source of food in countries ranging from the United States to South Korea. Over the past century, Pacific salmon have been extensively fished through both recreational, artisan and commercial fishing. In fact, since the 1970s there has been a nearly threefold increase in catch of Pacific salmon. In part, this decline in body weight has been related to the size selective effect of fishing gear used in the harvesting of salmon populations. The life history of salmon favors delayed reproduction because fecundity increased with body size. This means that multiple species of salmon would be looked at when it comes to conservation as well as multiple areas that each species live in. COSEWIC, a Canadian organization for the conservation of species, has named the Interior Fraser River Coho, the Cultus Lake Sockeye, and the Sakinaw Lake Sockeye to all be endangered. In British Columbia sockeye salmon in four different watersheds were certified by the Marine Stewardship Council, or MSC, as sustainable fisheries in July 2010 and the certification is good for a period of five years. In 2011 MSC also certified the Pink Salmon Fishery and as of 2012 The Chum Salmon Fisheries started their review under the MSC to become certified as a sustainable fishery.

The US government has been working to develop a nationwide policy for the salmon populations. The Pacific Salmon Stronghold Conservation Act was re submitted to congress and if passed will create geographic strongholds for salmon populations. Other policies include the Wild Salmon Policy which was enacted in 2005; its number one focus is the conservation of salmon off of the coasts. Even localized policies have begun, with one in Oregon which focuses on the southernmost watershed and was approved January 2013. In the Alaskan efforts, there is evidence of eight known regional groups of survival. It is also seen that the emigration of smolts (young salmon) from freshwater to other areas such as marine areas have shown significant consequences on the survival of different salmon groups. The Alaska Department of Fish and Game first received MSC, Marine Stewardship Council, Certification in sustainable seafood back in 2000.

Poaching is a threat to Oncorhynchus salmon and steelhead populations in Russia. It is estimated that illegal catching of salmon is 1.5 times more than the reported catch. The Wild Salmon Center is working with Russian authorities to try to help improve traceability systems so that markets can distinguish between legal sustainable salmon and the illegal salmon. The Wild Salmon Center has secured some of its protected locations for the salmon populations. In efforts with the WWF, the Wild Salmon Center was also able to have a Sockeye Salmon fishery certified as completely sustainable in 2012. The Iturup Island Pink and Chum Salmon Fishery was first certified in 2009 and was the first Russian salmon fishery to receive certification in sustainability by MSC. and Chinook in New Zealand (known there as quinnat, king or spring salmon). Aquaculture of Chinook and Coho salmon and Rainbow Trout are major industries in Chile and Australia. Chinook from Chile were released into Argentinean rivers and there were stockings of Coho and Sockeye Salmon and Rainbow Trout in Patagonia.

Some of the species in this genus are highly variable and a number of now obsolete taxa have been described. In 1989, morphological and genetic studies by Gerald Smith and Ralph Stearley indicated that trouts of the Pacific basin were genetically closer to Pacific salmon (Onchorhynchus species) than to the Salmos – 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 trouts into the genus Oncorhynchus. Currently, 12 species and numerous subspecies in this genus are recognized: Behnke (2002). Image Scientific name Common Name Subspecies Distribution120px Oncorhynchus apache (R. R. Miller, 1972) Apache trout, Arizona trout the upper Salt River watershed (Black and White rivers) and the upper Little Colorado River watershed Oncorhynchus chrysogaster (Needham & Gard, 1964) Mexican golden trout the headwaters of the Fuerte River, Sinaloa River, and Culiacán River drainages in the Sierra Madre Occidental120px Oncorhynchus clarki (J. Richardson, 1836) cutthroat trout O. c. clarki (J. Richardson, 1836) – coastal cutthroat trout
O. c. bouvieri (Jordan & Gilbert, 1883) – Yellowstone cutthroat trout
O. c. lewisi (Pratt & Graham, 1884) – westslope cutthroat trout
O. c. pleuriticus (Cope, 1872) – Colorado River cutthroat trout
O. c. alvordensis (Behnke, 2002) – Alvord cutthroat trout† (extinct)
O. c. behnkei (Montgomery, 1995) – Snake River fine spotted cutthroat trout
O. c. clarki f. crescentii – Lake Crescent cutthroat trout, Crescenti trout (sometimes O. c. crescentii)
O. c. henshawi (Richardson, 1836) – Lahontan cutthroat trout
O. c. macdonaldi (Jordan & Fisher, 1891) – yellowfin cutthroat trout† (extinct)
O. c. seleniris (John O. Snyder, 1933) – Paiute cutthroat trout
O. c. stomias (Cope, 1871) – greenback cutthroat trout
O. c. utah (Suckley, 1874) – Bonneville cutthroat trout
O. c. virginalis – Rio Grande cutthroat trout the Pacific Northwest coast from Alaska through British Columbia into northern California, in the Cascade Range, the Great Basin and throughout the Rocky Mountains, including southern Alberta120px Oncorhynchus gilae (R. R. Miller, 1950) Gila trout the Gila River in Arizona and New Mexico120px Oncorhynchus gorbuscha (Walbaum, 1792) pink salmon, humpback salmon the Pacific and Arctic coastal waters and rivers, from the Sacramento River in northern California to the Mackenzie River in Canada; and in the west from the Lena River in Siberia to Korea and Honshu, Japan120px Oncorhynchus kawamurae (D. S. Jordan & E. A. McGregor, 1925) kunimasu, black kokanee Lake Saiko120px Oncorhynchus keta (Walbaum, 1792) chum salmon, dog salmon, keta salmon, silverbrite salmon the Yukon River and deep into the Amur River basin in Asia. In lesser numbers they migrate thousands of kilometres up the Mackenzie River, the North Pacific, in the waters of Korea, Japan, and the Okhotsk and Bering Seas (Kamchatka, Chukotka, the Kuril Islands, Sakhalin, Khabarovsk Krai, Primorsky Krai), British Columbia in Canada, and from Alaska to California in the United States120px Oncorhynchus kisutch (Walbaum, 1792) coho salmon, silver salmon, silvers both sides of the North Pacific Ocean, from Hokkaidō, Japan and eastern Russia, around the Bering Sea to mainland Alaska, and south to Monterey Bay, California120px Oncorhynchus masou (Brevoort, 1856) masu salmon, cherry salmon, Japanese salmon, seema
O. m. masou (Brevoort, 1856) – masu salmon, cherry salmon, Japanese salmon
O. m. formosanus (D. S. Jordan & Ōshima, 1919) – Formosan landlocked salmon, Taiwanese salmon
O. m. macrostomus (Günther, 1877) – amago, red spotted masu salmon
O. m. ishikawae (Brevoort, 1856) – Satsukimasu salmon, masu salmon, yamame
O. m. rhodurus D. S. Jordan & E. A. McGregor, 1925 – Biwa trout
O. m. var. iwame Seiro Kimura & M. Nakamura, 1961 – Iwame trout, markless trout (intrapopoulation variant) Kamchatka, the Kuril Islands, Sakhalin, and Primorsky Krai south through Korea, Taiwan, and Japan120px Oncorhynchus mykiss (Walbaum, 1792) rainbow trout, steelhead, ocean trout, redband trout O. m. mykiss (Walbaum, 1792) – Kamchatkan rainbow trout
O. m. aguabonita (D. S. Jordan, 1892) – golden trout
O. m. irideus f. beardsleei – Beardslee trout, (sometimes O. m. beardsleei)
O. m. newberrii (Richardson, 1836) – Great Basin redband trout
O. m. irideus (Walbaum, 1792) – coastal rainbow trout
O. m. gairdneri (Richardson, 1836) – Columbia River redband trout
O. m. stonei – McCloud River redband trout
O. m. nelsoni (Evermann, 1908) – Baja California rainbow trout
O. m. ssp. – Mexican native trout
O. m. gilberti – Kern River rainbow trout
O. m. whitei (Evermann, 1906) – Little Kern golden trout the Pacific basin, from the Kamchatka Peninsula in Russia, east along the Aleutian Islands, throughout southwestern Alaska, the Pacific Coast of British Columbia and southeast Alaska, and south along the west coast of the U. S. to northern Mexico120px Oncorhynchus nerka (Walbaum, 1792) sockeye salmon, red salmon, blueback salmon, kokanee the Columbia River in the eastern Pacific (although individuals have been spotted as far south as the 10 Mile River on the Mendocino Coast of California) and in northern Hokkaidō Island in Japan in the western Pacific120px Oncorhynchus tshawytscha (Walbaum, 1792) Chinook salmon, blackmouth, black salmon, chub salmon, Columbia River salmon, hookbill salmon, king salmon, Quinnat salmon, spring salmon, Tyee salmon, winter salmon the Ventura River in California in the south to Kotzebue Sound in Alaska in the north