View source for Trout

{{Short description|Freshwater fish from subfamily Salmoninae}}
{{Other uses}}
{{pp-semi-indef|small=yes}}
{{more citations needed|date=May 2008}}
{{Use mdy dates|date=December 2017}}
[[File:Salmo trutta.jpg|thumb|[[Brown trout]]]]
'''Trout''' ({{plural form}}: trout) is a [[umbrella term|generic]] [[common name]] for numerous [[species]] of [[carnivorous]] [[freshwater fish|freshwater]] [[ray-finned fish]]es belonging to the [[genera]] ''[[Oncorhynchus]]'', ''[[Salmo]]'' and ''[[Salvelinus]]'', all of which are members of the [[subfamily (biology)|subfamily]] [[Salmoninae]] in the [[family (biology)|family]] [[Salmonidae]]. The word ''trout'' is also used for some similar-shaped but non-salmonid fish, such as the [[Cynoscion nebulosus|spotted seatrout/speckled trout]] (''Cynoscion nebulosus'', which is actually a [[Sciaenidae|croaker]]).
Trout are closely related to [[salmon]] and have similar [[fish migration|migratory]] [[biological life cycle|life cycle]]s. Most trout are strictly [[potamodromous]], spending their entire lives exclusively in [[freshwater]] [[lake]]s, [[river]]s and [[wetland]]s and migrating upstream to [[spawn (biology)|spawn]] in the shallow [[gravel]] [[stream bed|bed]]s of smaller [[headwater]] [[Stream|creek]]s. The hatched [[fry (fish)|fry]] and [[juvenile fish|juvenile]] trout, known as ''alevin'' and ''parr'', will stay upstream growing for years before migrating down to larger waterbodies as maturing [[adult]]s. There are some [[anadromous]] species of trout, such as the [[steelhead trout|steelhead]] (a coastal [[subspecies]] of [[rainbow trout]]) and [[sea trout]] (the sea-run subspecies of [[brown trout]]), that can spend up to three years of their adult lives at sea before returning to freshwater streams for spawning, in the same fashion as a [[salmon run]]. [[Brook trout]] and three other [[Extant taxon|extant]] species of [[North America]]n trout, despite the names, are actually [[Salvelinus|char (or charr)]], which are salmonids also closely related to trout and salmon.
Trout are classified as [[oily fish]]<ref>{{cite web|url=http://www.food.gov.uk/multimedia/faq/oilyfishfaq/oilyfishqa02|title=What are oily fish?|date=June 23, 2004|publisher=[[Food Standards Agency]]|access-date=February 17, 2013|archive-date=December 4, 2013|archive-url=https://web.archive.org/web/20131204081530/http://www.food.gov.uk/multimedia/faq/oilyfishfaq/oilyfishqa02|url-status=dead}}</ref> and have been important [[food fish]] for [[human]]s. As mid-level [[predator]]s, trout prey upon smaller [[aquatic animal]]s including [[crustacean]]s, [[insect]]s, [[worm]]s, [[baitfish]] and [[tadpole]]s, and themselves in turn are also important [[staple food|staple]] [[prey]] items for many wildlifes including [[brown bear]]s, [[otter]]s, [[raccoon]]s, [[birds of prey]] (e.g. [[sea eagle]]s, [[osprey]]s, [[fish owl]]s), [[gull]]s, [[cormorant]]s and [[kingfisher]]s, and other large aquatic predators. Discarded remains of trout also provide a source of nutrients for [[scavenger]]s, [[detrivore]]s and [[riparian]] [[flora]]e, making trout [[keystone species]] across [[aquatic ecosystem|aquatic]] and [[terrestrial ecosystem]]s.
==Species==
The name "trout" is commonly used for many (if not most) species in three of the seven [[genus|genera]] in the [[subfamily]] Salmoninae: ''[[Salmo]]'' ([[Atlantic Ocean|Atlantic]]), ''[[Oncorhynchus]]'' ([[Pacific Ocean|Pacific]]) and ''[[Salvelinus]]'' ([[circumpolar distribution|circum]]-[[arctic]]). Fish species referred to as trout include:
[[File:Marble trout from zadlaščica.jpg|upright=1.35|thumb|''[[Salmo]]'': [[marble trout]], ''S. marmoratus'']]
* Genus ''[[Salmo]]'', all extant species except [[Atlantic salmon]]
** [[Adriatic trout]], ''Salmo obtusirostris''
** [[Brown trout]], ''Salmo trutta''
*** [[River trout]], [[S. trutta fario|''S. t.'' morpha ''fario'']]
*** Lake trout/Lacustrine trout, [[S. trutta lacustris|''S. t''. morpha ''lacustris'']]
*** [[Sea trout]], ''S. t.'' morpha ''trutta''
** [[Flathead trout]], ''Salmo platycephalus''
** [[Marble trout]], Soca River trout or Soča trout – ''Salmo marmoratus''
** [[Ohrid trout]], ''Salmo letnica, S. balcanicus (extinct), S. lumi, and S. aphelios''
** [[Sevan trout]], ''Salmo ischchan''
[[File:Rainbow Trout.jpg|thumb|upright=1.35|''[[Oncorhynchus]]'': [[rainbow trout]], ''O. mykiss'']]
* Genus ''[[Oncorhynchus]]'', six of the 12 extant species
** [[Apache trout]], ''Oncorhynchus apache''
** [[Biwa trout]], ''Oncorhynchus masou rhodurus''
** [[Cutthroat trout]], ''Oncorhynchus clarki''
*** [[Coastal cutthroat trout]], ''O. c. clarki''
**** [[Crescenti trout]], ''O. c. c.'' f. crescenti
*** [[Alvord cutthroat trout]], ''O. c. alvordensis'' (extinct)
*** [[Bonneville cutthroat trout]], ''O. c. utah''
*** [[Humboldt cutthroat trout]], ''O. c. humboldtensis''
*** [[Lahontan cutthroat trout]], ''O. c. henshawi''
**** [[Whitehorse Basin cutthroat trout]]
*** [[Paiute cutthroat trout]], ''O. c. seleniris''
*** [[Snake River fine-spotted cutthroat trout]], ''O. c. behnkei''
*** [[Westslope cutthroat trout]], ''O. c. lewisi''
*** [[Yellowfin cutthroat trout]], ''O. c. macdonaldi'' (extinct)
*** [[Yellowstone cutthroat trout]], ''O. c. bouvieri''
*** [[Colorado River cutthroat trout]], ''O. c. pleuriticus''
*** [[Greenback cutthroat trout]], ''O. c. stomias''
*** [[Rio Grande cutthroat trout]], ''O. c. virginalis''
** [[Gila trout]], ''Oncorhynchus gilae''
** [[Rainbow trout]], ''Oncorhynchus mykiss''
*** [[Kamchatkan rainbow trout]], ''[[Oncorhynchus mykiss mykiss]]''
*** [[Columbia River redband trout]], ''Oncorhynchus mykiss gairdneri''
*** [[Coastal rainbow trout]] ([[steelhead]]), ''Oncorhynchus mykiss irideus''
**** [[Beardslee trout]], ''Oncorhynchus mykiss irideus var. beardsleei''
*** [[Great Basin redband trout]], ''Oncorhynchus mykiss newberrii''
*** [[Golden trout]], ''Oncorhynchus mykiss aguabonita''
**** [[Kern River rainbow trout]], ''[[Oncorhynchus mykiss aguabonita]] var. gilberti''
**** Sacramento golden trout, ''[[Oncorhynchus mykiss aguabonita]] var. stonei''
**** [[Little Kern golden trout]], ''[[Oncorhynchus mykiss aguabonita]] var. whitei''
*** [[Kamloops rainbow trout]], ''[[Oncorhynchus mykiss kamloops]]''
*** [[Baja California rainbow trout]], Nelson's trout, or San Pedro Martir trout, ''[[Oncorhynchus mykiss nelsoni]]''
*** [[Eagle Lake trout]], ''[[Oncorhynchus mykiss aquilarum]]''
*** [[McCloud River redband trout]], ''[[Oncorhynchus mykiss stonei]]''
*** [[Sheepheaven Creek redband trout]]
** [[Mexican golden trout]], ''Oncorhynchus chrysogaster''
[[File:Brook trout 1918.jpg|upright=1.35|thumb|''[[Salvelinus]]'': [[brook trout]], ''S. fontinalis'']]
* Genus ''[[Salvelinus]]'', five of the 52 extant species
** [[Brook trout]], ''Salvelinus fontinalis''
*** [[Aurora trout]], ''S. f. timagamiensis''
** [[Bull trout]], ''Salvelinus confluentus''
** [[Dolly Varden trout]], ''Salvelinus malma''
** [[Lake trout]], ''Salvelinus namaycush''
** [[Silver trout]], † ''Salvelinus agassizi'' (extinct)
*Hybrids
** [[Tiger trout]], ''Salmo trutta X Salvelinus fontinalis'' (infertile)
** Speckled Lake ([[Splake]]) trout, ''Salvelinus namaycush X Salvelinus fontinalis'' (fertile)
===Fish from other families===
*Pseudaphritidae
** Genus ''Pseudaphritis''
***[[Sand trout]], ''Pseudaphritis urvillii''
* [[Sciaenidae]]
** Genus ''Cynoscion''
*** [[Cynoscion nebulosus|Spotted sea-trout]], ''Cynoscion nebulosus''
==Anatomy==
Trout that live in different environments can have dramatically different colorations and patterns. Mostly, these colors and patterns form as [[camouflage]], based on the surroundings, and will change as the fish moves to different habitats. Trout in, or newly returned from the sea, can look very silvery, while the same fish living in a small stream or in an alpine lake could have pronounced markings and more vivid coloration; it is also possible that in some species, this signifies that they are ready to mate. In general, trout that are about to breed have extremely intense coloration and can look like an entirely different fish outside of spawning season. It is virtually impossible to define a particular color pattern as belonging to a specific breed; however, in general, wild fish are claimed to have more vivid colors and patterns.
Trout have fins entirely without spines, and all of them have a small [[adipose]] fin along the back, near the tail. The pelvic fins sit well back on the body, on each side of the anus. The [[swim bladder]] is connected to the [[esophagus]], allowing for gulping or rapid expulsion of air, a condition known as [[physostome]]. Unlike many other physostome fish, trout do not use their bladder as an auxiliary device for [[oxygen]] uptake, relying solely on their [[gills]].
There are many species, and even more populations, that are isolated from each other and morphologically different. However, since many of these distinct populations show no significant genetic differences, what may appear to be a large number of species is considered a much smaller number of distinct species by most [[Ichthyology|ichthyologists]]. The trout found in the eastern [[United States]] are a good example of this. The [[brook trout]], the [[aurora trout]], and the (extinct) [[silver trout]] all have physical characteristics and colorations that distinguish them, yet [[gene]]tic analysis shows that they are one species, ''Salvelinus fontinalis''.
[[Lake trout]] (''Salvelinus namaycush''), like brook trout, belong to the char genus. Lake trout inhabit many of the larger lakes in North America, and live much longer than [[rainbow trout]], which have an average maximum lifespan of seven years. Lake trout can live many decades, and can grow to more than {{convert|30|kg}}.
==Habitat==
[[File:Forel farm Sochi.jpg|thumb|upright=1.15|A trout farm in [[Sochi]], [[Russia]]]]
As salmonids, trout are [[coldwater fish]] that are usually found in cool ({{convert|50|-|60|F|C|disp=or}}), clear streams, wetlands and lakes, although many of the species have [[anadromous]] populations as well. Juvenile trout are referred to as troutlet, troutling or parr. They are distributed naturally throughout [[North America]], northern [[Asia]] and [[Europe]]. Several species of trout were introduced to [[Australia]] and [[New Zealand]] by amateur fishing enthusiasts in the 19th century, effectively displacing and endangering several [[Upland and lowland (freshwater ecology)|upland]] native fish species. The introduced species included [[brown trout]] from [[England]] and [[rainbow trout]] from [[California]]. The rainbow trout has a [[steelhead]] subspecies, generally accepted as coming from [[Sonoma Creek]]. The rainbow trout of New Zealand still show the steelhead tendency to run up rivers in winter to spawn.<ref>{{Cite journal |doi = 10.1016/S0165-7836(98)00215-X|title = Spawning of anadromous rainbow trout, Oncorhynchus mykiss (Walbaum): A threat to sea trout, Salmo trutta L., populations?|journal = Fisheries Research|volume = 40|pages = 55–63|year = 1999|last1 = Landergren|first1 = Peter| issue=1 | bibcode=1999FishR..40...55L }}</ref>
In Australia, the rainbow trout was introduced in 1894 from New Zealand and is an extremely popular gamefish in recreational angling.<ref name="fishes">{{cite web|last1=Gomon|first1=Martin|last2=Bray|first2=Dianne|title=Rainbow Trout, Oncorhynchus mykiss|url=http://www.fishesofaustralia.net.au/home/species/2083|website=Fishes of Australia|access-date=August 30, 2014|archive-date=September 4, 2014|archive-url=https://web.archive.org/web/20140904090858/http://www.fishesofaustralia.net.au/home/species/2083|url-status=dead}}</ref>
Despite severely impacting the distribution and abundance of native Australian fish, such as the [[climbing galaxias]], millions of rainbow and other trout species are released annually from government and private hatcheries.<ref name="fishes" />
The closest resemblance of seema trout and other trout family can be found in the [[Himalayas|Himalayan Region]] of India, Nepal, Bhutan, Pakistan and in [[Tian Shan]] mountains of [[Kyrgyzstan]].{{clarify|date=November 2019}}
==Diet==
[[File:Truite doree.jpg|thumb|upright=1.15|[[Golden trout]], ''Oncorhynchus aguabonita'']]
Trout generally feed on other fish, and soft-bodied aquatic [[invertebrate]]s, such as [[Diptera|flies]], [[mayfly|mayflies]], [[Trichoptera|caddisflies]], [[Plecoptera|stoneflies]], [[mollusk]]s and [[Odonata|dragonflies]]. In lakes, various species of [[Plankton|zooplankton]] often form a large part of the diet. In general, trout longer than about {{convert|300|mm}} prey almost exclusively on fish, where they are available. Adult trout will devour smaller fish up to one-third of their length. Trout may feed on [[shrimp]], [[mealworm]]s, [[Chironomidae|bloodworms]], [[insect]]s, small animal parts, and [[eel]].
Trout who swim the streams love to feed on land animals, aquatic life, and flies.<ref name="Trout Food {{!}} Stream Explorers">{{Cite web|url=http://www.streamexplorers.org/fish-facts/trout-food|title=Trout Food {{!}} Stream Explorers|website=www.streamexplorers.org|access-date=2020-04-09}}</ref> Most of their diet comes from macroinvertebrates, or animals that do not have a backbone like snails, worms, or insects. They also eat flies, and most people who try to use lures to fish trout mimic flies because they are one of trout's most fed on meals.<ref name="Trout Food {{!}} Stream Explorers"/> Trout enjoy certain land animals, including insects like grasshoppers. They also eat small animals like mice when they fall in. (Although only large trout have mouths capable of eating mice.) They consume a diet of aquatic life like minnows or crawfish as well. Trout have a diverse diet they follow; they have plenty of different oppositions.<ref name="Trout Food {{!}} Stream Explorers"/>
== Trout as food==
[[File:Baked trout.jpg|thumb|upright=1.15|Baked trout]]
Compared to other salmonids, trout are somewhat more [[fish bone|bony]], but the flesh is generally considered delicious, and the texture is often indistinguishable from [[salmon as food|that of salmon]]. The flavor of the flesh is heavily influenced by the diet of the fish. For example, trout that have been feeding on crustaceans tend to be more flavorful than those feeding primarily on [[insect]]s and [[larva]]e. Because of their popularity, trout are often raised on [[fish farm]]s and then [[fish stocking|stocked]] into heavily fished waters, in an effort to mask the effects of [[overfishing]].{{Citation needed|date=May 2022|reason=Unsupported claims about overfishing}} Farmed trout are also sold commercially as [[seafood]], although they are not [[saltwater fish]]. Trout meat is typically prepared the same way as salmon, often by [[smoking (cooking)|smoking]].<ref>{{Cite book|last=Tennant|first=S. G. B.|url=https://books.google.com/books?id=HKPF_S849O0C&pg=PA27|title=Trout|date=2000|publisher=Willow Creek Press|isbn=978-1-57223-276-1|language=en |page=27}}</ref>
In [[Mainland China]], farm-raised [[rainbow trout]] from [[Qinghai]] was officially sanctioned to be labeled and sold domestically as salmon, which caused much controversy regarding [[food safety]] and [[consumer protection|consumer rights violation]],<ref>{{cite web|url=https://www.scmp.com/news/china/society/article/2159890/rainbow-trout-same-salmon-china-says-yes-despite-food-safety|title=Is rainbow trout the same as salmon? China says yes despite food safety fears|last=Zheng|first=Sarah|date=2018-08-15|publisher=[[South China Morning Post]]|accessdate=2023-05-08}}</ref> as [[raw fish dish]]es or ''[[yusheng]]'' using [[Atlantic salmon]] are gaining popularity in [[southern China]]. Farmed rainbow trout is much cheaper than the imported Atlantic salmon and the meat are indistinguishable to the untrained eyes, and the news of trout being sold as salmon triggered public scrutiny accusing seafood suppliers of [[bait-and-switch]] and [[business ethics|unethical business practice]]s. Also, many people believe freshwater trout are more prone to [[fish parasite|parasite]]s than oceanic salmon (even though both live in freshwater for significant periods of their life cycles) and thus unsafe for [[raw foodism|raw eating]].
=== Nutritional value ===
One [[fish fillet|fillet]] of trout (about {{cvt|79|g|disp=or}}) contains:<ref>{{cite web |url=http://www.nal.usda.gov/fnic/foodcomp/search/ |title=Search the USDA National Nutrient Database for Standard Reference |publisher=Nal.usda.gov |access-date=December 26, 2011 |archive-date=March 3, 2015 |archive-url=https://web.archive.org/web/20150303184216/http://www.nal.usda.gov/fnic/foodcomp/search/ |url-status=dead }}</ref>
* [[Food energy|Energy]]: {{cvt|117|kcal|kJ|order=flip}}
* [[Fat]] (g): 5.22
* [[Carbohydrate]]s (g): 0
* [[Dietary fiber|Fiber]]s (g): 0
* [[Protein]] (g): 16.41
* [[Cholesterol]] (mg): 46
==Trout fishing==
Trout are very popular freshwater [[game fish]] highly prized especially by creek fishermen, because they generally put up a good fight when caught with a [[fish hook|hook]] and [[fishing line|line]]. As trout are [[predatory fish]], [[angling#Lure fishing|lure fishing]] (which use [[replica]] baits called [[fishing lure|lure]]s to imitate live prey) is the predominant form of [[sport fishing]] involving trout, although traditional [[fishing bait|bait fishing]] techniques using [[fishing float|float]]s and/or [[fishing sinker|sinker]]s (particularly with moving [[live food|live bait]]s such as [[baitfish]], [[crayfish]] or [[aquatic insect]]s) are also successful, especially against [[fish stocking|stocked]] trout that are [[fish hatchery|hatchery]]/[[fish farm|farm]]-raised and thus more accustomed to [[fish feed|artificial feed]]s.
Many species of trout, most noticeably [[rainbow trout]] and [[brown trout]], have been widely [[introduced species|introduced]] into waterbodies outside of their [[native range]]s purely for the sake of [[recreational fishing]], and some of these introduced populations have even become [[invasive species|invasive]] in the new habitats.
===River fishing===
While trout can be caught with a normal [[fishing rod|rod]] and [[fishing reel|reel]], [[fly fishing]] is a distinctive lure fishing method developed for trout, and now extended to other species. Due to the high proportion of [[insect]]s and small [[crustacean]]s within the trout's diet, small lures made of [[fly tying|hand-tied]] [[hair]]s and [[thread (yarn)|thread]]s are often used to imitate these aquatic [[invertebrate]]s that the trout prey upon. These ultralight [[fly lure]]s cannot be [[casting (fishing)|cast]] adequately by conventional techniques, and a specialized heavy line (i.e. fly line) is needed to launch the lure.
Understanding how moving water shapes the stream channel makes it easier to find trout. In most streams, the current creates a riffle-run-pool pattern that repeats itself over and over. A deep pool may hold a big brown trout, but rainbow trout and smaller brown trout are likely found in runs. [[Riffle]]s are where fishers will find small trout, called troutlet, during the day and larger trout crowding in during morning and evening feeding periods.<ref>{{Cite web|url=https://cotrout.org/|title=Cotrout - The Outdoor Resources|website=Cotrout|language=en-US|access-date=2019-06-03}}</ref>
* Riffles have a fast current and shallow water. This gives way to a bottom of gravel, rubble or boulder. Riffles are morning and evening feeding areas. Trout usually spawn just above or below riffles, but may spawn right in them.
* Runs are deeper than riffles with a moderate current and are found between riffles and pools. The bottom is made up of small gravel or rubble. These hot spots hold trout almost anytime, if there is sufficient cover.
* Pools are smoother and look darker than the other areas of the stream. The deep, slow-moving water generally has a bottom of silt, sand, or small gravel. Pools make good midday resting spots for medium to large trout.
* It is recommended that when fishing for trout, that the fisher(s) should use line in the 4–8&nbsp;lb test for streamfish, and stronger line with the same diameter for trout from the sea or from a large lake, such as Lake Michigan. It is also recommended to use a hook size 8–5 for trout of all kind. Trout, especially farm-raised ones, tend to like [[salmon roe]]s, [[worm]]s, [[minnow]]s, cut bait, [[maize]], or [[marshmallow]]s.
===Ice fishing===
Fishing for trout under the ice generally occurs in depths of {{Convert|4 to 8|ft}}. Because trout are cold water fish, during the winter they move from up-deep to the shallows, replacing the small fish that inhabit the area during the summer. Trout in winter constantly cruise in shallow depths looking for food, usually traveling in groups, although bigger fish may travel alone and in water that's somewhat deeper, around {{Convert|12|ft}}. Rainbow, Brown, and Brook trout are the most common trout species caught through the ice.<ref>{{Cite web|last=Straw|first=Matt|date=2012-12-05|title=Ice Fishing Trout|url=https://www.in-fisherman.com/editorial/ice-fishing-trout/153754|access-date=2023-02-07|website=In-Fisherman|language=en}}</ref>
===Trout fishing records===
By information from [[International Game Fish Association]] (IGFA), the most outstanding records are:<ref>{{cite web |url=http://wrec.igfa.org |title=IGFA World Records |publisher=International Game Fish Association |access-date=November 1, 2015}}</ref>
* [[Brook trout]] caught by Dr. W. Cook in the Nipigon River, Canada, on July 1, 1916, that weighed {{convert|6.57|kg|lboz|abbr=on}}
* [[Cutthroat trout]] caught by John Skimmerhorn in Pyramid Lake located in Nevada, US, on December 1, 1925, that weighed {{convert|18.59|kg|lboz|abbr=on}}
* [[Bull trout]] caught by N. Higgins in Lake Pend Oreille located in Idaho, US, on October 27, 1949, that weighed {{convert|14.51|kg|lboz|abbr=on}}
* [[Golden trout]] caught by Chas Reed in Cooks Lake located in Wyoming, US, on August 5, 1948, that weighed {{convert|4.98|kg|lboz|abbr=on}}
* [[Rainbow trout]] caught by Sean Konrad in Lake Diefenbaker, Canada, on September 5, 2009, that weighed {{convert|21.77|kg|lboz|abbr=on}}
* [[Lake trout]] caught by Lloyd Bull in Great Bear Lake, Canada, on August 19, 1995, that weighed {{convert|32.65|kg|lboz|abbr=on}}
===Baits===
<gallery>
File:Achroia grisella caterpillars kleine wasmot rupsen (1).jpg|[[Waxworm]]s are used as [[Fishing bait|live-bait]] for trout fishing.
File:Corn borer.jpg|[[European corn borer|Corn worm]]s are also excellent [[Fishing bait|live-bait]] when trout fishing.
File:Plecoptera.jpg|[[Nymph (biology)|Nymph]] of a golden [[stonefly]] are used as [[Fishing bait|live-bait]] for trout fishing.
File:Ecdyonurus tobiironis Kurotanigawakagerou larva.jpg|[[Nymph (biology)|Nymph]] [[mayfly]]
File:Ikorka.jpg|[[Salmon roe]] ([[red caviar]])
File:Jyväskylä - worm.jpg|Worms are cheap and effective bait to use for trout and most types of fish.
File:Orange-trout-worms2.jpg|A [[soft plastic lure]] or "trout worm"
</gallery><gallery mode="nolines" perrow="3" caption="Fly Fishing Flies">
File:MoscaWoolyBugger.jpg|Wooly buggers can be tied in every color imaginable.
File:Pink-roe-egg-fly 02.jpg|Egg patterns are effective for steelhead and trout in rivers.
File:Muddler minnow fly.JPG|Muddler minnow
</gallery>
== Declines in native trout populations ==
Salmonid populations in general have been declining due to numerous factors, including [[invasive species]], hybridization, wildfires, and climate change. Native salmonid fish in the western and southwestern United States are threatened by non-native species that were introduced decades ago. Non-native salmonids were introduced to enrich recreational fishing;<ref>{{Cite journal|last=Quist|first=Michael|date=2004|title=Bioinvasive species and the preservation of cutthroat trout in the western United States: ecological, social, and economic issues|journal=Environmental Science & Policy|volume=7|issue=4|pages=303–313|doi=10.1016/j.envsci.2004.05.003|bibcode=2004ESPol...7..303Q }}</ref> however, they quickly started outcompeting and displacing native salmonids upon their arrival. Non-native, invasive species are quick to adapt to their new environment and learn to outcompete any native species, making them a force the native salmon and trout have to reckon with. Not only do the non-native fish drive the native fish to occupy new niches, but they also try to hybridize with them, contaminating the native gene construction. As more hybrids between native and non-native fish are formed, the lineage of the pure fish is continuously being contaminated by other species and soon may no longer represent the sole native species. The [[Rio Grande cutthroat trout]] (''Oncorhynchus clarki virginalis'') are susceptible to hybridization with other salmonids such as [[rainbow trout]] (''Oncorhynchus mykiss'') and yield a new "[[cutbow]]" trout, which is a contamination of both lineages’ genes. One solution to this issue is implemented by [[New Mexico Department of Game and Fish]] [[fish hatchery|hatcheries]]: stock only sterile fish in river streams. Hatcheries serve as a reservoir of fish for recreational activities but growing and stocking non-sterile fish would worsen the hybridization issue on a quicker, more magnified time scale. By stocking sterile fish, the native salmonids can't share genes with the non-native hatchery fish, thus, preventing further gene contamination of the native trout in New Mexico. Fire is also a factor in deteriorating [[Gila trout]] (''Oncorhynchus gilae'') populations because of the ash and soot that can enter streams following fires.<ref>{{Cite web|url=http://www.wildlife.state.nm.us/fishing/native-new-mexico-fish/gila-trout-recovery-angling/|title=Gila Trout Recovery and Angling|website=New Mexico Department of Game and Fish|access-date=Dec 2, 2019}}</ref> The ash lowers water quality, making it more difficult for the Gila trout to survive. In some New Mexico streams, the native Gila trout will be evacuated from streams that are threatened by nearby fires and be reintroduced after the threat is resolved.
[[Climate change]] is also dwindling native salmonid populations. [[Global warming]] continually affects various cold-water fish such as trout, especially as inland waterbodies are more prone to warming than oceans. With an increase of temperature along with changes in spawning river flow, an abundance of trout species are effected negatively. In the past, a mere {{Convert|8|F-change}} increase was predicted to eliminate half of the native [[brook trout]] in the Southern [[Appalachian Mountains]].<ref>{{Cite book|title=Climate Change and Cold Water Fish|publisher=United States Environmental Protection Agency|year=1999}}</ref> Trout generally prefer streams with colder water ({{cvt|50|-|60|F|disp=or}}) to spawn and thrive, but raising water temperatures are altering this ecosystem and further deteriorate native populations.
== See also ==
{{Portal|Food}}
* [[Introduced trout in lake ecosystems]]
* [[List of smoked foods]]
* [[Trout tickling]]
== References ==
{{Reflist}}
== Further reading ==
* Robert J. Behnke, ''Trout and Salmon of North America.'' Illustrated by Joseph R. Tomelleri. New York: The Free Press, 2002.
* Jen Corrinne Brown, ''Trout Culture: How Fly Fishing Forever Changed the Rocky Mountain West.'' Seattle, WA: University of Washington Press, 2015.
==External links==
{{Commons category}}
{{Cookbook}}
* [http://www.trout.co.uk Trout.co.uk] – Website focused purely on fishing for trout
* [https://www.tu.org/ Trout Unlimited] – Conserving, protecting and restoring North America's coldwater fisheries and their watersheds
* [http://www.troutlet.com/Trout-Science-W30C54.aspx "Trout Science,"] www.troutlet.com, 2000.
{{Seafood}}
{{Meat|state=collapsed}}
{{Authority control}}
[[Category:Fish common names]]
[[Category:Salmonidae]]
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[[Category:Holarctic fauna]]