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100-568: In the Little Delaware River the wild brown trout and brook trout populations are supplemented with the stocking of about 700 brown trout yearlings each year. The fish are stocked in a 0.8 miles (1.3 km) zone at the mouth and a 1.2 miles (1.9 km) zone downstream of the hamlet of Bovina Center . Brown trout are the dominant wild trout in the stream, but there are also large amounts of brook trout upstream of Bovina Center. The Little Delaware River's watershed makes up for 7.84% of

200-423: A mutation–selection balance . It is predicted that a viral quasispecies at a low but evolutionarily neutral and highly connected (that is, flat) region in the fitness landscape will outcompete a quasispecies located at a higher but narrower fitness peak in which the surrounding mutants are unfit, "the quasispecies effect" or the "survival of the flattest". There is no suggestion that a viral quasispecies resembles

300-495: A riverine ecotype called river trout or Salmo trutta morpha fario ; a lacustrine ecotype or S. trutta morpha lacustris , also called the lake trout (not to be confused with the lake trout in North America ); and anadromous populations known as the sea trout or S. trutta morpha trutta , which upon adulthood migrate downstream to the oceans for much of its life and only returns to fresh water to spawn in

400-400: A "classical" method of determining species, such as with Linnaeus, early in evolutionary theory. However, different phenotypes are not necessarily different species (e.g. a four-winged Drosophila born to a two-winged mother is not a different species). Species named in this manner are called morphospecies . In the 1970s, Robert R. Sokal , Theodore J. Crovello and Peter Sneath proposed

500-424: A 'smallest clade' idea" (a phylogenetic species concept). Mishler and Wilkins and others concur with this approach, even though this would raise difficulties in biological nomenclature. Wilkins cited the ichthyologist Charles Tate Regan 's early 20th century remark that "a species is whatever a suitably qualified biologist chooses to call a species". Wilkins noted that the philosopher Philip Kitcher called this

600-428: A connected series of neighbouring populations, each of which can sexually interbreed with adjacent related populations, but for which there exist at least two "end" populations in the series, which are too distantly related to interbreed, though there is a potential gene flow between each "linked" population. Such non-breeding, though genetically connected, "end" populations may co-exist in the same region thus closing

700-432: A different species from its ancestors. Viruses have enormous populations, are doubtfully living since they consist of little more than a string of DNA or RNA in a protein coat, and mutate rapidly. All of these factors make conventional species concepts largely inapplicable. A viral quasispecies is a group of genotypes related by similar mutations, competing within a highly mutagenic environment, and hence governed by

800-525: A favoured target for fly fishing . Sea trout are fished for especially at night using wet flies . Brown trout can be caught with lures such as spoons, spinners, jigs, plugs, plastic worm imitations, and live or dead baitfish . Brown trout rarely form hybrids with other species; if they do, they are almost invariably infertile. One such example is the tiger trout , a hybrid with the brook trout . Field studies have demonstrated that brown trout fed on several animal prey species, aquatic invertebrates being

900-508: A genetic boundary suitable for defining a species concept is present. DNA barcoding has been proposed as a way to distinguish species suitable even for non-specialists to use. One of the barcodes is a region of mitochondrial DNA within the gene for cytochrome c oxidase . A database, Barcode of Life Data System , contains DNA barcode sequences from over 190,000 species. However, scientists such as Rob DeSalle have expressed concern that classical taxonomy and DNA barcoding, which they consider

1000-494: A lighter golden cast with some red spotting and fewer dark spots. Notably, both strains can show considerable individual variation from this general description. Early stocking efforts in the United States used fish taken from Scotland and Germany . The brown trout is a medium-sized fish, growing to 20 kg (44 lb) or more and a length of about 100 cm (39 in) in some localities, although in many smaller rivers,

1100-465: A lineage should be divided into multiple chronospecies , or when populations have diverged to have enough distinct character states to be described as cladistic species. Species and higher taxa were seen from the time of Aristotle until the 18th century as categories that could be arranged in a hierarchy, the great chain of being . In the 19th century, biologists grasped that species could evolve given sufficient time. Charles Darwin 's 1859 book On

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1200-652: A marked reduction in intraspecific competition in the fish population, facilitating the partitioning of resources. First feeding of newly emerged fry is very important for brown trout survival in this phase of the lifecycle, and first feeding can occur even prior to emergence. Fry start to feed before complete yolk absorption and the diet composition of newly emerged brown trout is composed of small prey such as chironomid larvae or baetid nymphs. The species has been widely introduced for sport fishing into North America , South America , Australia , New Zealand , and many other countries, including Bhutan , where they are

1300-514: A mature weight of 1.0 kg (2.2 lb) or less is common. S. t. lacustris reaches an average length of 40–80 cm (16–31 in) with a maximum length of 140 cm (55 in) and about 60 pounds (27 kg). On September 11, 2009, a 41.45-lb (18.80-kg) brown trout was caught by Tom Healy in the Manistee River system in Michigan, setting a new state record. As of late December 2009,

1400-492: A misnomer, need to be reconciled, as they delimit species differently. Genetic introgression mediated by endosymbionts and other vectors can further make barcodes ineffective in the identification of species. A phylogenetic or cladistic species is "the smallest aggregation of populations (sexual) or lineages (asexual) diagnosable by a unique combination of character states in comparable individuals (semaphoronts)". The empirical basis – observed character states – provides

1500-449: A particular species, including which genus (and higher taxa) it is placed in, is a hypothesis about the evolutionary relationships and distinguishability of that group of organisms. As further information comes to hand, the hypothesis may be corroborated or refuted. Sometimes, especially in the past when communication was more difficult, taxonomists working in isolation have given two distinct names to individual organisms later identified as

1600-400: A perfect model of life, it is still a useful tool to scientists and conservationists for studying life on Earth, regardless of the theoretical difficulties. If species were fixed and clearly distinct from one another, there would be no problem, but evolutionary processes cause species to change. This obliges taxonomists to decide, for example, when enough change has occurred to declare that

1700-568: A popular game fish of European anglers for centuries. It was first mentioned in angling literature as "fish with speckled skins" by Roman author Aelian ( circa 200 AD) in On the Nature of Animals . This work is credited with describing the first instance of fly fishing for trout, the trout being the brown trout found in Macedonia. The Treatyse of Fysshynge with an Angle (1496) by Dame Juliana Berners , O.S.B

1800-421: A reduction in dissolved oxygen levels which can cause "summer kills" of local populations if temperatures remain high for sufficient duration and deeper/cooler or fast, turbulent more oxygenated water is not accessible to the fish. This phenomenon can be further exacerbated by eutrophication of rivers due to pollution —often from the use of agricultural fertilizers within the drainage basin . Overfishing

1900-400: A short way of saying that something applies to many species within a genus, but not to all. If scientists mean that something applies to all species within a genus, they use the genus name without the specific name or epithet. The names of genera and species are usually printed in italics . However, abbreviations such as "sp." should not be italicised. When a species' identity is not clear,

2000-564: A slender body with a long, narrow head. The mouth is large, and on its roof, vomerine teeth are developed in a zig-zag pattern. The caudal fin is deltaform without forking, unlike that of the related Atlantic salmon ( Salmo salar ). Dark and red spots are often present on the sides, but do not extend to the tail. Parr trout (juvenile) often have a red margin on their adipose fin , with dark blotches along their sides that also become inconspicuous with age. Freshwater brown trout range in colour from largely silver with relatively few spots and

2100-404: A specialist may use "cf." before the epithet to indicate that confirmation is required. The abbreviations "nr." (near) or "aff." (affine) may be used when the identity is unclear but when the species appears to be similar to the species mentioned after. With the rise of online databases, codes have been devised to provide identifiers for species that are already defined, including: The naming of

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2200-523: A species as groups of actually or potentially interbreeding natural populations, which are reproductively isolated from other such groups. It has been argued that this definition is a natural consequence of the effect of sexual reproduction on the dynamics of natural selection. Mayr's use of the adjective "potentially" has been a point of debate; some interpretations exclude unusual or artificial matings that occur only in captivity, or that involve animals capable of mating but that do not normally do so in

2300-400: A species as determined by a taxonomist. A typological species is a group of organisms in which individuals conform to certain fixed properties (a type), so that even pre-literate people often recognise the same taxon as do modern taxonomists. The clusters of variations or phenotypes within specimens (such as longer or shorter tails) would differentiate the species. This method was used as

2400-488: A species. All species definitions assume that an organism acquires its genes from one or two parents very like the "daughter" organism, but that is not what happens in HGT. There is strong evidence of HGT between very dissimilar groups of prokaryotes , and at least occasionally between dissimilar groups of eukaryotes , including some crustaceans and echinoderms . The evolutionary biologist James Mallet concludes that there

2500-685: A species. Generally the term includes the unknown element of a distinct act of creation. Many authors have argued that a simple textbook definition, following Mayr's concept, works well for most multi-celled organisms , but breaks down in several situations: Species identification is made difficult by discordance between molecular and morphological investigations; these can be categorised as two types: (i) one morphology, multiple lineages (e.g. morphological convergence , cryptic species ) and (ii) one lineage, multiple morphologies (e.g. phenotypic plasticity , multiple life-cycle stages). In addition, horizontal gene transfer (HGT) makes it difficult to define

2600-519: A taxonomic decision at the discretion of cognizant specialists, is not governed by the Codes of Zoological or Botanical Nomenclature, in contrast to the PhyloCode , and contrary to what is done in several other fields, in which the definitions of technical terms, like geochronological units and geopolitical entities, are explicitly delimited. The nomenclatural codes that guide the naming of species, including

2700-506: A traditional biological species. The International Committee on Taxonomy of Viruses has since 1962 developed a universal taxonomic scheme for viruses; this has stabilised viral taxonomy. Most modern textbooks make use of Ernst Mayr 's 1942 definition, known as the Biological Species Concept as a basis for further discussion on the definition of species. It is also called a reproductive or isolation concept. This defines

2800-447: A variation on the morphological species concept, a phenetic species, defined as a set of organisms with a similar phenotype to each other, but a different phenotype from other sets of organisms. It differs from the morphological species concept in including a numerical measure of distance or similarity to cluster entities based on multivariate comparisons of a reasonably large number of phenotypic traits. A mate-recognition species

2900-515: A variety of reasons. Viruses are a special case, driven by a balance of mutation and selection , and can be treated as quasispecies . Biologists and taxonomists have made many attempts to define species, beginning from morphology and moving towards genetics . Early taxonomists such as Linnaeus had no option but to describe what they saw: this was later formalised as the typological or morphological species concept. Ernst Mayr emphasised reproductive isolation, but this, like other species concepts,

3000-413: A white belly, to the more well-known brassy reddish-brown cast fading to creamy white on the fish's belly, with medium-sized spots surrounded by lighter halos. The more silver forms can be mistaken for rainbow trout. Regional variants include the so-called "Loch Leven" trout, distinguished by larger fins, a slimmer body, and heavy black spotting, but lacking red spots. The continental European strain features

3100-438: Is "an entity composed of organisms which maintains its identity from other such entities through time and over space, and which has its own independent evolutionary fate and historical tendencies". This differs from the biological species concept in embodying persistence over time. Wiley and Mayden stated that they see the evolutionary species concept as "identical" to Willi Hennig 's species-as-lineages concept, and asserted that

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3200-700: Is a 97-centimetre (38 in) fish caught in Milwaukee Harbor, Wisconsin on 16 December 2011. The spawning behaviour of brown trout is similar to that of the closely related Atlantic salmon . A typical female produces about 2,000 eggs per kg (900 eggs per lb) of body weight at spawning. Brown trout can live 20 years, but as with the Atlantic salmon, a high proportion of males die after spawning, and probably fewer than 20% of anadromous female kelts recover from spawning . The migratory forms grow to significantly larger sizes for their age due to abundant forage fish in

3300-586: Is a fish that feeds clean and purely, in the swiftest streams, and on the hardest gravel; and that he may justly contend with all fresh water fish, as the Mullet may with all sea fish, for precedency and daintiness of taste; and that being in right season, the most dainty palates have allowed precedency to him. Throughout the 17th, 18th, and 19th centuries, angling authors, mostly British, some French, and later American, writing about trout fishing were writing about fishing for brown trout. Once brown trout were introduced into

3400-400: Is a group of sexually reproducing organisms that recognise one another as potential mates. Expanding on this to allow for post-mating isolation, a cohesion species is the most inclusive population of individuals having the potential for phenotypic cohesion through intrinsic cohesion mechanisms; no matter whether populations can hybridise successfully, they are still distinct cohesion species if

3500-427: Is a problem where anglers fail to identify and return mature female fish into the lake or stream. Each large female removed can result in thousands fewer eggs released back into the system when the remaining fish spawn. In small streams, brown trout are important predators of macroinvertebrates , and declining brown trout populations in these specific areas affect the entire aquatic food web . Global climate change

3600-458: Is a set of organisms adapted to a particular set of resources, called a niche, in the environment. According to this concept, populations form the discrete phenetic clusters that we recognise as species because the ecological and evolutionary processes controlling how resources are divided up tend to produce those clusters. A genetic species as defined by Robert Baker and Robert Bradley is a set of genetically isolated interbreeding populations. This

3700-452: Is a species of salmonid ray-finned fish and the most widely distributed species of the genus Salmo , endemic to most of Europe , West Asia and parts of North Africa , and has been widely introduced globally as a game fish , even becoming one of the world's worst invasive species outside of its native range . Brown trout are highly adaptable and have evolved numerous ecotypes / subspecies . These include three main ecotypes:

3800-483: Is also of concern. S. trutta morpha fario prefers well-oxygenated water in the temperature range of 60 to 65 °F (16 to 18 °C). S. trutta bones from an archaeological site in Italy, and ancient DNA extracted from some of these bones, indicate that both abundance and genetic diversity increased markedly during the colder Younger Dryas period, and fell during the warmer Bølling-Allerød event. Cover or structure

3900-414: Is called speciation . Charles Darwin was the first to describe the role of natural selection in speciation in his 1859 book The Origin of Species . Speciation depends on a measure of reproductive isolation , a reduced gene flow. This occurs most easily in allopatric speciation, where populations are separated geographically and can diverge gradually as mutations accumulate. Reproductive isolation

4000-412: Is called the specific name or the specific epithet (in botanical nomenclature , also sometimes in zoological nomenclature ). For example, Boa constrictor is one of the species of the genus Boa , with constrictor being the species' epithet. While the definitions given above may seem adequate at first glance, when looked at more closely they represent problematic species concepts. For example,

4100-456: Is considered a foundational work in the history of recreational fishing , especially fly fishing. One of the most prominent fish described in the work is the brown trout of English rivers and streams: The trout, because he is a right dainty fish and also a right fervent biter, we shall speak of next. He is in season from March until Michaelmas. He is on clean gravel bottom and in a stream. The renowned The Compleat Angler (1653) by Izaak Walton

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4200-403: Is described formally, in a publication that assigns it a unique scientific name. The description typically provides means for identifying the new species, which may not be based solely on morphology (see cryptic species ), differentiating it from other previously described and related or confusable species and provides a validly published name (in botany) or an available name (in zoology) when

4300-671: Is further weakened by the existence of microspecies , groups of organisms, including many plants, with very little genetic variability, usually forming species aggregates . For example, the dandelion Taraxacum officinale and the blackberry Rubus fruticosus are aggregates with many microspecies—perhaps 400 in the case of the blackberry and over 200 in the dandelion, complicated by hybridisation , apomixis and polyploidy , making gene flow between populations difficult to determine, and their taxonomy debatable. Species complexes occur in insects such as Heliconius butterflies, vertebrates such as Hypsiboas treefrogs, and fungi such as

4400-726: Is hard or even impossible to test. Later biologists have tried to refine Mayr's definition with the recognition and cohesion concepts, among others. Many of the concepts are quite similar or overlap, so they are not easy to count: the biologist R. L. Mayden recorded about 24 concepts, and the philosopher of science John Wilkins counted 26. Wilkins further grouped the species concepts into seven basic kinds of concepts: (1) agamospecies for asexual organisms (2) biospecies for reproductively isolated sexual organisms (3) ecospecies based on ecological niches (4) evolutionary species based on lineage (5) genetic species based on gene pool (6) morphospecies based on form or phenotype and (7) taxonomic species,

4500-454: Is important to trout, and they are more likely to be found near submerged rocks and logs, undercut banks, and overhanging vegetation. Structure provides protection from predators, bright sunlight, and higher water temperatures. Access to deep water for protection in winter freezes, or fast water for protection from low oxygen levels in summer are also ideal. Trout are more often found in heavy and strong currents. Defining characteristics include

4600-403: Is no easy way to tell whether related geographic or temporal forms belong to the same or different species. Species gaps can be verified only locally and at a point of time. One is forced to admit that Darwin's insight is correct: any local reality or integrity of species is greatly reduced over large geographic ranges and time periods. The botanist Brent Mishler argued that the species concept

4700-468: Is not valid, notably because gene flux decreases gradually rather than in discrete steps, which hampers objective delimitation of species. Indeed, complex and unstable patterns of gene flux have been observed in cichlid teleosts of the East African Great Lakes . Wilkins argued that "if we were being true to evolution and the consequent phylogenetic approach to taxa, we should replace it with

4800-425: Is replete with advice on "the trout": The Trout is a fish highly valued, both in this and foreign nations. He may be justly said, as the old poet said of wine, and we English say of venison, to be a generous fish: a fish that is so like the buck, that he also has his seasons; for it is observed, that he comes in and goes out of season with the stag and buck. Gesner says, his name is of a German offspring; and says he

4900-586: Is similar to Mayr's Biological Species Concept, but stresses genetic rather than reproductive isolation. In the 21st century, a genetic species could be established by comparing DNA sequences. Earlier, other methods were available, such as comparing karyotypes (sets of chromosomes ) and allozymes ( enzyme variants). An evolutionarily significant unit (ESU) or "wildlife species" is a population of organisms considered distinct for purposes of conservation. In palaeontology , with only comparative anatomy (morphology) and histology from fossils as evidence,

5000-594: Is threatened by hybridisation, but this can be selected against once a pair of populations have incompatible alleles of the same gene, as described in the Bateson–Dobzhansky–Muller model . A different mechanism, phyletic speciation, involves one lineage gradually changing over time into a new and distinct form (a chronospecies ), without increasing the number of resultant species. Horizontal gene transfer between organisms of different species, either through hybridisation , antigenic shift , or reassortment ,

5100-906: The Arctic Ocean to the Atlas Mountains in North Africa. The western limit of their native range is Iceland in the north Atlantic, while the eastern limit is in Aral Sea tributaries in Afghanistan and Pakistan . Brown trout have been widely introduced into suitable environments around the world, including North and South America, Australasia, Asia, and South and East Africa. Introduced brown trout have established self-sustaining, wild populations in many introduced countries. The first introductions were in Australia in 1864 when 300 of 1500 brown trout eggs from

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5200-817: The Cold Spring Hatchery operated by Mather, one in Caledonia, New York , operated by pisciculturalist Seth Green , and other hatchery in Northville, Michigan . Additional shipments of "von Behr" brown trout eggs arrived in 1884. In 1885, brown trout eggs from Loch Leven, Scotland , arrived in New York. These "Loch Leven" brown trout were distributed to the same hatcheries. Over the next few years, additional eggs from Scotland, England, and Germany were shipped to U.S. hatcheries. Behnke (2007) believed all life forms of brown trout—anadromous, riverine, and lacustrine—were imported into

5300-574: The Falklands . Species A species ( pl. : species) is a population of organisms in which any two individuals of the appropriate sexes or mating types can produce fertile offspring , typically by sexual reproduction . It is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity . Other ways of defining species include their karyotype , DNA sequence, morphology , behaviour, or ecological niche . In addition, paleontologists use

5400-523: The ICZN for animals and the ICN for plants, do not make rules for defining the boundaries of the species. Research can change the boundaries, also known as circumscription, based on new evidence. Species may then need to be distinguished by the boundary definitions used, and in such cases the names may be qualified with sensu stricto ("in the narrow sense") to denote usage in the exact meaning given by an author such as

5500-560: The Natal and Cape Provinces of South Africa took place in 1890 and 1892, respectively. By 1909, brown trout were established in the mountains of Kenya . The first introductions into the Himalayas in northern India took place in 1868, and by 1900, brown trout were established in Kashmir and Madras . In the 1950s and 1960s, Edgar Albert de la Rue  [ fr ] , a French geologist, began

5600-562: The Northwest Territories . Introductions into South America began in 1904 in Argentina . Brown trout are now established in Chile , Peru and the Falklands . Sea-run forms of brown trout exceeding 20 lb (9.1 kg) are caught by local anglers on a regular basis. The first introductions into the U.S. started in 1883 when Fred Mather , a New York pisciculturist and angler , under

5700-738: The River Itchen survived a four-month voyage from Falmouth, Cornwall to Melbourne on the sailing ship Norfolk . By 1866, 171 young brown trout were surviving in a Plenty River hatchery in Tasmania . Thirty-eight young trout were released in the river, a tributary of the River Derwent in 1866. By 1868, the Plenty River hosted a self-sustaining population of brown trout which became a brood source for continued introduction of brown trout into Australian and New Zealand rivers. Successful introductions into

5800-399: The fly agaric . Natural hybridisation presents a challenge to the concept of a reproductively isolated species, as fertile hybrids permit gene flow between two populations. For example, the carrion crow Corvus corone and the hooded crow Corvus cornix appear and are classified as separate species, yet they can hybridise where their geographical ranges overlap. A ring species is

5900-1029: The gravel beds of headstreams . Sea trout in Ireland and Great Britain have many regional names: sewin in Wales , finnock in Scotland , peal in the West Country , mort in North West England , and white trout in Ireland. The lacustrine and riverine morphs of brown trout are both potamodromous , meaning they are also migratory, though only between freshwater bodies. Lacustrine trout mainly inhabit large lakes with calm and stratified deep water, while riverine trout forms fluvial populations typically in large rivers but sometimes in shallower creeks and alpine streams , both still migrating upstream during reproductive seasons. Anadromous and potamodromous morphs coexisting in

6000-498: The jaguar ( Panthera onca ) of Latin America or the leopard ( Panthera pardus ) of Africa and Asia. In contrast, the scientific names of species are chosen to be unique and universal (except for some inter-code homonyms ); they are in two parts used together : the genus as in Puma , and the specific epithet as in concolor . A species is given a taxonomic name when a type specimen

6100-406: The "cynical species concept", and arguing that far from being cynical, it usefully leads to an empirical taxonomy for any given group, based on taxonomists' experience. Other biologists have gone further and argued that we should abandon species entirely, and refer to the "Least Inclusive Taxonomic Units" (LITUs), a view that would be coherent with current evolutionary theory. The species concept

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6200-622: The Origin of Species explained how species could arise by natural selection . That understanding was greatly extended in the 20th century through genetics and population ecology . Genetic variability arises from mutations and recombination , while organisms themselves are mobile, leading to geographical isolation and genetic drift with varying selection pressures . Genes can sometimes be exchanged between species by horizontal gene transfer ; new species can arise rapidly through hybridisation and polyploidy ; and species may become extinct for

6300-498: The U.S. By 1900, 38 states and two territories had received stocks of brown trout. Their adaptability resulted in most of these introductions establishing wild, self-sustaining populations. The fish is not considered to be endangered , although some individual stocks are under various degrees of stress mainly through habitat degradation, overfishing , and artificial propagation leading to introgression . Increased frequency of excessively warm water temperatures in high summer causes

6400-693: The U.S. and intermingled genetically to create what he calls the American generic brown trout and a single subspecies the North European brown trout ( S. t. trutta ). In April 1884, the U.S. Fish Commission released 4900 brown trout fry into the Baldwin River , a tributary of the Pere Marquette River in Michigan. This was the first release of brown trout into U.S. waters. Between 1884 and 1890, brown trout were introduced into suitable habitats throughout

6500-507: The U.S. in the 1880s, they became a major subject of American angling literature. In 1889, Frederic M. Halford , a British angler, author published Dry-Fly Fishing in Theory and Practice , a seminal work codifying a half century of evolution of fly fishing with floating flies for brown trout. In the late 19th century, American angler and writer Theodore Gordon , often called the "Father of American Dry Fly Fishing", perfected dry-fly techniques for

6600-558: The West Branch Delaware River's drainage area. The United States Geological Survey (USGS) maintains one stream gauge along the Little Delaware River. The station by the Village of Delhi has been in operation since October 1937, but only making maximum measurements since December 1996. It is located on the left bank 10 feet (3.0 m) downstream from the bridge on Thomson Cross Road and 1.5 miles (2.4 km) upstream from

6700-405: The abbreviation "sp." in the singular or "spp." (standing for species pluralis , Latin for "multiple species") in the plural in place of the specific name or epithet (e.g. Canis sp.). This commonly occurs when authors are confident that some individuals belong to a particular genus but are not sure to which exact species they belong, as is common in paleontology . Authors may also use "spp." as

6800-570: The amount of hybridisation is insufficient to completely mix their respective gene pools . A further development of the recognition concept is provided by the biosemiotic concept of species. In microbiology , genes can move freely even between distantly related bacteria, possibly extending to the whole bacterial domain. As a rule of thumb, microbiologists have assumed that members of Bacteria or Archaea with 16S ribosomal RNA gene sequences more similar than 97% to each other need to be checked by DNA–DNA hybridisation to decide if they belong to

6900-536: The authority of the U.S. Fish Commissioner, Spencer Baird , obtained brown trout eggs from a Baron Lucius von Behr, president of the German Fishing Society  [ de ] . The von Behr brown trout came from both mountain streams and large lakes in the Black Forest region of Baden-Württemberg . The original shipment of "von Behr" brown trout eggs were handled by three hatcheries, one on Long Island ,

7000-474: The biological species concept, "the several versions" of the phylogenetic species concept, and the idea that species are of the same kind as higher taxa are not suitable for biodiversity studies (with the intention of estimating the number of species accurately). They further suggested that the concept works for both asexual and sexually-reproducing species. A version of the concept is Kevin de Queiroz 's "General Lineage Concept of Species". An ecological species

7100-505: The biological species concept, a cladistic species does not rely on reproductive isolation – its criteria are independent of processes that are integral in other concepts. Therefore, it applies to asexual lineages. However, it does not always provide clear cut and intuitively satisfying boundaries between taxa, and may require multiple sources of evidence, such as more than one polymorphic locus, to give plausible results. An evolutionary species, suggested by George Gaylord Simpson in 1951,

7200-428: The boundaries between closely related species become unclear with hybridisation , in a species complex of hundreds of similar microspecies , and in a ring species . Also, among organisms that reproduce only asexually , the concept of a reproductive species breaks down, and each clone is potentially a microspecies. Although none of these are entirely satisfactory definitions, and while the concept of species may not be

7300-433: The concept of a chronospecies can be applied. During anagenesis (evolution, not necessarily involving branching), some palaeontologists seek to identify a sequence of species, each one derived from the phyletically extinct one before through continuous, slow and more or less uniform change. In such a time sequence, some palaeontologists assess how much change is required for a morphologically distinct form to be considered

7400-416: The concept of the chronospecies since fossil reproduction cannot be examined. The most recent rigorous estimate for the total number of species of eukaryotes is between 8 and 8.7 million. About 14% of these had been described by 2011. All species (except viruses ) are given a two-part name , called a "binomial". The first part of a binomial is the genus to which the species belongs. The second part

7500-435: The evidence to support hypotheses about evolutionarily divergent lineages that have maintained their hereditary integrity through time and space. Molecular markers may be used to determine diagnostic genetic differences in the nuclear or mitochondrial DNA of various species. For example, in a study done on fungi , studying the nucleotide characters using cladistic species produced the most accurate results in recognising

7600-399: The family Galaxiidae , which also have affinity for well-oxygenated, cold streams. Brown trout additionally are voracious predators of invertebrates and can carry microbial pathogens like Aeromonas salmonicida . Genetic background is a very important factor when determining the success of trout populations, this information is vital to restore and enhance previous populations. Because of

7700-559: The first comprehensive text, The Book of The Sea Trout , specifically addressing angling techniques for the anadromous forms of brown trout. Introductions of brown trout into the American West created new angling opportunities, none so successful from an angling perspective as was the introduction of browns into the upper Firehole River in Yellowstone National Park in 1890. One of the earliest accounts of trout fishing in

7800-808: The fish captured by Healy was confirmed by both the International Game Fish Association and the Fresh Water Fishing Hall of Fame as the new all-tackle world record for the species. This fish, which supplanted the former world record from the Little Red River in Arkansas, has in turn been exceeded by a 20.1-kilogram (44 lb) specimen caught in the Ohau Canal in Twizel, New Zealand on 27 October 2020. The all-tackle length IGFA world record

7900-509: The focus of a specialised fly fishery. The first planting in the United States occurred on April 11, 1884, into the Baldwin River, one mile east of Baldwin, Michigan . Brown trout have had serious negative impacts on upland native fish species in some of the countries where they have been introduced, particularly Australia. In Chile , Australia , New Zealand and other locations in the southern hemisphere, brown trout compete with fish from

8000-512: The introduction of several species of salmonids on the remote Kerguelen Islands in the southern Indian Ocean . Of the seven species introduced, only brook trout , Salvelinus fontinalis , and brown trout survived to establish wild populations. The first introductions in Canada occurred in 1883 in Newfoundland and continued until 1933. The only Canadian regions without brown trout are Yukon and

8100-426: The most abundant prey items. However, brown trout also feed on other taxa such as terrestrial invertebrates (e.g. Hymenoptera) or other fish. Moreover, in brown trout, as in many other fish species, a change in the diet composition normally occurs during the life of the fish, and piscivorous behaviour is most frequent in large brown trout. These shifts in the diet during fish lifecycle transitions may be accompanied by

8200-576: The mouth. This station had a maximum discharge of about 6,100 cubic feet per second (170 m/s) and a gauge height of 8.51 feet (2.59 m) from floodmark on January 19, 1996, and a minimum discharge of .8 cubic feet per second (0.023 m/s) on August 10–12, 1964 and September 24–25,1964. This article related to a river in New York is a stub . You can help Misplaced Pages by expanding it . Brown trout Salmo trutta morpha trutta Salmo trutta morpha fario Salmo trutta morpha lacustris The brown trout ( Salmo trutta )

8300-578: The newly arrived, but difficult-to-catch brown trout in Catskill rivers such as the Beaverkill and Neversink Rivers . In the early 20th century, British angler and author G. E. M. Skues pioneered nymphing techniques for brown trout on English chalk streams. His Minor Tactics of the Chalk Stream (1910) began a revolution in fly fishing techniques for trout. In 1917, Scottish author Hamish Stuart published

8400-478: The numerous fungi species of all the concepts studied. Versions of the phylogenetic species concept that emphasise monophyly or diagnosability may lead to splitting of existing species, for example in Bovidae , by recognising old subspecies as species, despite the fact that there are no reproductive barriers, and populations may intergrade morphologically. Others have called this approach taxonomic inflation , diluting

8500-585: The paper is accepted for publication. The type material is usually held in a permanent repository, often the research collection of a major museum or university, that allows independent verification and the means to compare specimens. Describers of new species are asked to choose names that, in the words of the International Code of Zoological Nomenclature , are "appropriate, compact, euphonious, memorable, and do not cause offence". Books and articles sometimes intentionally do not identify species fully, using

8600-557: The park is from Mary Trowbridge Townsend's 1897 article in Outing Magazine "A Woman's Trout Fishing in Yellowstone Park" in which she talks about catching the von Behr trout in the river: Long dashes down stream taxed my unsteady footing; the sharp click and whirr of the reel resounded in desperate efforts to hold him somewhat in check; another headlong dash, then a vicious bulldog shake of the head as he sawed back and forth across

8700-674: The person who named the species, while the antonym sensu lato ("in the broad sense") denotes a wider usage, for instance including other subspecies. Other abbreviations such as "auct." ("author"), and qualifiers such as "non" ("not") may be used to further clarify the sense in which the specified authors delineated or described the species. Species are subject to change, whether by evolving into new species, exchanging genes with other species, merging with other species or by becoming extinct. The evolutionary process by which biological populations of sexually-reproducing organisms evolve to become distinct or reproductively isolated as species

8800-487: The result of misclassification leading to questions on whether there really are any ring species. The commonly used names for kinds of organisms are often ambiguous: "cat" could mean the domestic cat, Felis catus , or the cat family, Felidae . Another problem with common names is that they often vary from place to place, so that puma, cougar, catamount, panther, painter and mountain lion all mean Puma concolor in various parts of America, while "panther" may also mean

8900-573: The ring. Ring species thus present a difficulty for any species concept that relies on reproductive isolation. However, ring species are at best rare. Proposed examples include the herring gull – lesser black-backed gull complex around the North pole, the Ensatina eschscholtzii group of 19 populations of salamanders in America, and the greenish warbler in Asia, but many so-called ring species have turned out to be

9000-418: The rocks. Every wile inherited from generations of wily ancestors was tried until, in a moment of exhaustion, the net was slipped under him. Wading ashore with my prize, I had barely time to notice his size—a good four-pounder, and unusual markings, large yellow spots encircled by black, with great brilliancy of iridescent color—when back he flopped into the water and was gone. However, I took afterward several of

9100-517: The same river appear genetically identical. What determines whether they migrate to sea or not remains unknown. The scientific name of the brown trout is Salmo trutta . The specific epithet trutta derives from the Latin trutta , meaning, literally, " trout ". Behnke (2007) relates that the brown trout was the first species of trout described in the 1758 edition of Systema Naturae by Swedish zoologist Carl Linnaeus . Systema Naturae established

9200-508: The same species. This concept was narrowed in 2006 to a similarity of 98.7%. The average nucleotide identity (ANI) method quantifies genetic distance between entire genomes , using regions of about 10,000 base pairs . With enough data from genomes of one genus, algorithms can be used to categorize species, as for Pseudomonas avellanae in 2013, and for all sequenced bacteria and archaea since 2020. Observed ANI values among sequences appear to have an "ANI gap" at 85–95%, suggesting that

9300-529: The same species. When two species names are discovered to apply to the same species, the older species name is given priority and usually retained, and the newer name considered as a junior synonym, a process called synonymy . Dividing a taxon into multiple, often new, taxa is called splitting . Taxonomists are often referred to as "lumpers" or "splitters" by their colleagues, depending on their personal approach to recognising differences or commonalities between organisms. The circumscription of taxa, considered

9400-859: The same variety, known in the Park as the Von Baer [sic] trout, and which I have since found to be the Salmo fario , the veritable trout of Izaak Walton. Within the US, brown trout introductions have created self-sustaining fisheries throughout the country. Many are considered "world-class" such as in the Great Lakes and in several Arkansas tailwaters. Outside the U.S. and outside its native range in Europe, introduced brown trout have created "world-class" fisheries in New Zealand, Patagonia , and

9500-502: The species concept and making taxonomy unstable. Yet others defend this approach, considering "taxonomic inflation" pejorative and labelling the opposing view as "taxonomic conservatism"; claiming it is politically expedient to split species and recognise smaller populations at the species level, because this means they can more easily be included as endangered in the IUCN red list and can attract conservation legislation and funding. Unlike

9600-448: The system of binomial nomenclature for animals . Salmo trutta was used to describe anadromous or sea-run forms of brown trout. Linnaeus also described two other brown trout species in 1758. Salmo fario was used for riverine forms. Salmo lacustris was used for lake-dwelling forms. The native range of brown trout extends from northern Norway and White Sea tributaries in Russia in

9700-513: The trout's importance as a food and game fish, it has been artificially propagated and stocked in many places in its range, and fully natural populations (uncontaminated by allopatric genomes ) probably exist only in isolated places, for example in Corsica or in high alpine valleys on the European mainland. Farming of brown trout has included the production of infertile triploid fish by increasing

9800-670: The water temperature just after fertilisation of eggs, or more reliably, by a process known as pressure shocking. Triploids are favoured by anglers because they grow faster and larger than diploid trout. Proponents of stocking triploids argue, because they are infertile, they can be introduced into an environment that contains wild brown trout without the negative effects of cross-breeding. However, stocking triploids may damage wild stocks in other ways. Triploids certainly compete with diploid fish for food, space, and other resources. They could also be more aggressive than diploid fish and they may disturb spawning behaviour. The brown trout has been

9900-456: The waters where they spend most of their lives. Sea trout are more commonly female in less nutrient-rich rivers. Brown trout are active both by day and by night and are opportunistic feeders. While in freshwater, their diets frequently include invertebrates from the streambed , other fish, frogs, mice, birds, and insects flying near the water's surface. The high dietary reliance upon insect larvae , pupae , nymphs , and adults allows trout to be

10000-537: The wild. It is difficult to define a species in a way that applies to all organisms. The debate about species concepts is called the species problem. The problem was recognised even in 1859, when Darwin wrote in On the Origin of Species : I was much struck how entirely vague and arbitrary is the distinction between species and varieties. He went on to write: No one definition has satisfied all naturalists; yet every naturalist knows vaguely what he means when he speaks of

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