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From both a modern and a historical perspective there is little
doubt that the Arctic charr, Salvelinus alpinus, in Britain and Ireland (as
well as elsewhere) is a ‘difficult’ species. Historically 15 separate species
have been recognised from populations in Britain and Ireland and there
have been recent attempts to reassert these specific names. H...
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... In the mountainous regions of Fennoscandia, the Alps, and the British Isles, arctic char lives exclusively in lakes, where it forms a huge number of local forms. Although some of them are proposed to be considered certain species by the features of some morphological characters (Kottelat and Freyhof, 2007), there are still no convincing facts indicating the species status of the forms of charrs of the British Isles (Adams and Maitland, 2007) and Fennoscandia . Considering the only species of the genus Salvelinus (S. alpinus) inhabiting entire Europe is much more reasonable. ...
Until recently, cold-water species were believed to have appeared in Europe during the Quaternary glaciations. However, ample molecular genetic and zoogeographic data obtained in recent years allow us to state confidently that the formation of the cold-water fauna of Europe was a long process with several distinct steps. Species whose ancestors migrated westwards from the Far East through the Paratethys invaded southern and then central Europe as early as the Miocene. The first wave of invaders from Siberia found its way into central Europe later, in the Pliocene. The second wave of Siberian species entered Europe in an interglacial period (possibly through a strait that connected the future White Sea to the future Baltic Sea). The third wave of invaders from Siberia entered northeastern Europe during the last deglaciation (approximately 10000 years ago), along with small groups of migrants from North America and the Pacific basin. The cross distribution of cold-water species (from Europe to Siberia) was extremely rare. Apparently, such a high evolutionary and adaptive plasticity of many Siberian aquatic organisms is apparently related to their origin from the giant Siberian sea lake water body that existed east of the Urals over several millions of years and experienced many fluctuations in water level, temperature, and salinity.
... The charrs manifest a full range of transition paths from the groups with non-inherited contrasting growth rate to genetically independent sympatric species (Jonsson and Jonsson 2001;Wilson et al. 2004;Klemetsen 2010;Reist et al. 2013;. The typical divergence modes in charrs proceed along the pelagic-benthic resource axes, the depth gradient and sharing lacustrine-riverine spawning sites (Jonsson and Jonsson 2001;Wilson et al. 2004;Adams and Maitland 2007;Reist et al. 2013;. Moreover, adaptive divergence within the coastal zone by shifts in the feeding tactics was also singled out as one of the main charr divergence modes (Sandlund et al. 1992;Knudsen et al. 2011;Chavarie et al. 2013;Markevich et al. 2017a). ...
Adaptive radiation in fishes entering novel post-glacial lakes ubiquitously gives rise to a set of typical forms specializing under the pressure of the same ecological gradients. The world’s most diverse flock of salmonids from Lake Kronotskoe (Kamchatka, N-E Asia) serves as a good model to study evolutionary divergence modes. Eight forms with different feeding types and habitat preferences are known to originate from Salvelinus malma. To determine the phasing of the flock radiation we analyzed morphometry, muscle isotope content, parasite fauna abundance and microsatellite DNA polymorphism in the sympatric forms inhabiting the lake. We found that seven out of eight morphologically independent forms can be distinguished by a stable feeding niche through comparing the stomach content, isotopic status and parasite fauna abundance. Five eco-morphs were found to be genetically independent, while three other morphs fell into one cluster without any significant restriction of the gene flow among the members. Partitioning of the resources in pelagic—benthic, epilimnetic—deepwater and lacustrine—riverine environments leads to divergence of the most genetically and morphologically distant forms. Smaller genetic and morphometric distances were found for the form pairs diverged along one or two of these gradients. The divergence of the last three eco-morphs in feeding tactics within the coastal zone is not associated with differentiation in microsatellite polymorphism suggesting a more recent and/or subtle specialization within this environment.
... In addition, in some cases, Kottelat and Freyhof (2007) used species descriptions that were based on few specimens and were described long ago without inclusion of more recent information. For example, 12 out of the 15 designated Salvelinus species from Britain and Ireland are based on descriptions from more than 100 years ago, of which 7 species were described from just one or two specimens (Adams and Maitland 2007). Few specimens from a limited number of locations should often be insufficient to grasp the large intraspecific variations of salmonids and their remarkable phenotypic plasticity (Chapter 6). ...
... Few specimens from a limited number of locations should often be insufficient to grasp the large intraspecific variations of salmonids and their remarkable phenotypic plasticity (Chapter 6). Adams and Maitland (2007) examined the original descriptions of the 15 designated species and concluded that all the species belong to Salvelinus alpinus. Genetic studies have also confirmed synonyms of some designated species (e.g., Snoj et al. 2011), but the old designations have not been updated in the influential Kottelat and Freyhof (2007) book. ...
... However, Kottelat and Freyhof (2007) recognize 4 species of Brown Trout and 19 species of Arctic Char here. While these Brown Trout species are supported by phylogeographical evidence (Ferguson 2004;McKeown et al. 2010), most of the char species are described solely by phenetic characteristics, many of which are known to be phenotypically plastic (e.g., Adams et al. 2003), and thus the validity of such species has been questioned (Adams and Maitland 2007). ...
This chapter covers Britain (England, Scotland, and Wales), Ireland (Northern Ireland and Republic of Ireland), Iceland, the Faroe Islands, and Greenland. Brown Trout Salmo trutta, which belongs to the Eurasian and North African species complex, is native to all regions in the North Atlantic Isles (NAI) with the exception of Greenland. Arctic Char Salvelinus alpinus is native to all regions covered. Since it is not possible to provide details of the many thousands of Brown Trout and Arctic Char populations in the NAI, general information is provided on the current status together with a number of examples dealing with specific life histories, populations of national importance, sympatric populations and regions where detailed studies have been undertaken. Current management and conservation activities are outlined. Introduced non-native species of trout and char are covered briefly.
The book, either as a hard copy or pdf, and pdfs of individual chapters are available for purchase at: https://fisheries.org/bookstore/all-titles/professional-and-trade/55081c/
... For some species complexes of char, the diversity has been described as a "taxonomic nightmare" (Klemetsen 2010). Understanding and developing classification schemes for char has been particularly difficult because of the occurrence of morphological polymorphisms within water bodies occupied by char populations (Adams and Maitland 2007;Reist et al. 2013). For example, Arctic Char found in lakes from Scandinavia, the United Kingdom, and North America may have phenotypic varieties in the same water body (Adams et al. 1998;Power et al. 2009;Knudsen et al. 2016a). ...
Origins, Species Diversity, and Ecological Diversification in Trout and Char
... It also generates a bias against the assignment of populations to species, with frequent reference to species complexes (e.g. brown trout -Pustovrh, Snoj, & Bajec, 2014;Arctic char-Taylor, 2016) and often differing views on the classification of distinct populations as species (e.g. in northern hemisphere fishes (Adams & Maitland, 2007;Kottelat and Freyhof, 2007). ...
... The novel profundal benthic form found in Laidon appears to be the ecological and morphological equivalent to profundal benthic forms of Arctic char as found in adjacent Lochs Rannoch and Ericht (Adams et al., 1998(Adams et al., , 2007Walker et al., 1988). Although unverified second-hand accounts of its presence exist (Campbell, 1979) tend to be excluded from the pelagic and deep benthic zones by char (Jonsson & Jonsson, 2011;Klemetsen et al., 2003;Langeland et al., 1991) suggesting that the evolution of a profundal trout form may not co-occur where Arctic char are present. ...
• The full extent of sympatric intraspecific population diversity (SIPD) i.e. structuring into multiple genetically distinct Mendelian populations, remains uncertain for most lacustrine fish species, particularly in northern lakes. However, increasing application of molecular genetics is advancing understanding and has shown both that many known intraspecific sympatric lacustrine morphological and behavioural polymorphisms represent SIPD, and resolved the existence of phenotypically cryptic structuring.
• Uncertainty remains as only a few northern lakes have been comprehensively surveyed and existing studies focus on known phenotypic polymorphisms or exploit ad hoc field sampling, marker selection and data analysis methods. Such unfocused approaches constrain resolving power and increase the likelihood of failing to detect SIPD when present.
• Brown trout (Salmo trutta L.) in a previously unstudied Scottish lake were collected by 3D stratified random netting. They were screened with both an arbitrary set of molecular markers and markers pre‐selected for their ability to resolve regional allopatric brown trout population structuring and data analysed by both Bayesian and non‐Bayesian approaches.
• Depth clines for mitochondrial and microsatellite markers variation were observed and found to arise from different, but overlapping, depth distributions of four genetically distinct piscivorous, limnetic, shallow benthic, and profundal benthic populations. This is the highest number of ecologically and phenotypically distinct sympatric brown populations identified in any lake to date, and includes the first reported profundal benthic form.
• The detection of the SIPD in Loch Laidon depended critically on the random 3D sampling and using markers preselected for their power to differentiate regional allopatric populations of trout, as well as aided by using both Bayesian and non‐Bayesian analytical approaches.
• The findings support the view that the extent of ecologically and evolutionarily significant SIPD is probably underestimated in brown trout and other fish species, and probably is a significant component of the biodiversity in many northern hemisphere lakes.
... The assumption that representatives of the genus Salvelinus are closest to the ancestor of salmonids is favored by the fact that Arctic charrs are distinguished by a very high ecological and morphological diversity (reviews: Savvaitova, 1989;Adams and Maitland, 2007;Knudsen et al., 2016), which is characteristic of the ancient groups (Mamkaev, 1968;Rozhnov, 2006). ...
We have analyzed the partial sequences of the mitochondrial COI gene along with the amino acid sequences of cytochrome oxidase subunit I, encoded by this gene region, in representatives of 11 genera of salmonoid fish. For amino acid sequences, two alternative networks are constructed with outgroups represented by either Esocoidei or Osmeroidei as the supposed ancestral groups. This way, Osmeroidei appear to be closer to the salmonoid fish than Esocoidei, and their presence in the network as an outgroup explains the available data on the morphology and karyology of salmonoids much better. A number of the results of this study are fundamentally new. In particular, the slowing down of the molecular evolution of the grayling (Thymallidae) is shown. We conclude that the charr (Salvelinus) is one of the modern genera of salmonoids closest to their ancestor. The hypothesis of the phylogenetic proximity of the genera Brachymystax, Hucho, and Salmo has been confirmed. We also discuss the possibility that it is namely the changes in the amino acid sequence of cytochrome oxidase subunit I that lead to postzygotic reproductive isolation between taxa.
... Salvelinus alpinus and S. taranetzi seems to be the leaders in forming of lake morphs. Both species are pre-adapted to living in lacustrine environment, and in dozens of lakes from two to four morphs are normally formed (Jonsson and Jonsson, 2001;Adams and Maitland, 2007;Reist et al., 2013). ...
... According to the data obtained at the end of the 19ththe beginning of the 20th century, in northern Britain (Scotland) and Ireland 15 species of the lake charrs were described (Adams and Maitland, 2007). The overview of the diversity (Alexander and Adams, 2000) includes the description of 24 lakes, some of which are inhabited by several sympatric morphs. ...
To date a considerable amount of data on sympatric diversification of the laсustrine fish has been accumulated and many important advances made. However, the evolutionary mechanisms of the process still remain unclear. The paper discusses fish polymorphism in the water bodies of different latitudes, but the major focus is the question of sympatry in the charrs of the genus Salvelinus across the northern lakes. Numerous cases of diversification were comparatively analyzed, which provides evidence for the existence of several main pathways of evolutionary process. The pathways are controlled by environmental factors, which determine the structure of the lake ecosystems in the northern latitudes.
... Sympatric morphs displaying discrete phenotypes commonly originate and develop in parallel, but are characterized by contrasting life histories. Diversification is often closely associated with trophic adaptations (Jonsson & Jonsson, 2001;Adams & Maitland, 2007;Reist et al., 2013), and some of the most striking examples of sympatric diversification in animals takes place in lakedwelling fishes (Schluter, 1996;Robinson & Parsons, 2002;Klemetsen, 2013). ...
Identifying the mechanisms initiating sympatric diversification in vertebrates has remained a conceptual challenge. Here we analyze an assemblage of sympatric charr (Salvelinus malma) morphs from landlocked Lake Kronotskoe basin as a model to uncover the divergence pathways in freshwater fishes during the early life history stages. All morphs have distinct developmental biology, but a similar developmental rate retardation compared to the ancestor. Our study reveals that adult morphological differences, which acquire functionality at maturation, originate in the early juvenile stages due to heterochrony in skeletogenesis and allometric changes triggered by variation in metabolic activity. The craniofacial differences among the morphs result from asynchronous development of several skeletal modules. The accelerated ossification of teeth‐armed bones occurs in predatory feeding morphs, while cranial cover ossification is promoted in benthivorous morphs. These contrasting growth patterns have led to seven phenotypes that span a range far beyond the ancestral variability. The most distinct morphs are a riverine‐spawning, epilimnetic predator and a lacustrine‐spawning, profundal benthic feeder. Taken together, we argue that the adaptive morphological differentiation in these sympatric freshwater fishes is driven by diverging patterns in ossification rate and metabolic activity against a background of uneven somatic growth. This divergence is primarily associated with basic environmental differences on the nursery grounds that might be unrelated to resource use. This non‐heritable phenotype divergence is then exposed to natural selection that could result in further adaptive genetic changes.
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... Рекордсменами по количеству озерных форм среди гольцов являются представители S. alpinus и S. taranetzi. Обе группы хорошо преадаптированы к озерному образу жизни и в десятках водоемов образуют от двух до четырех форм (Jonsson, Jonsson, 2001;Adams, Maitland, 2007;Reist et al., 2013). Морфологический полиморфизм в симпатрических пучках S. alpinus не уступает межвидовому морфологическому разнообразию в роде, а в некоторых случаях -превосходит его (рис. ...
... Согласно сводке А. Вильсона (Wilson et al., 2004) генетическая сегрегация выявлена для 6 из 18 местных озер. В северной Британии (Шотландии) и Ирландии по материалам конца XIX -начала XX века было описано 15 видов озерных гольцов (Adams, Maitland, 2007). Ревизия этого разнообразия (Alexander, Adams, 2000) включает описание популяций из 24 озер, в некоторых из которых отмечено наличие нескольких симпатричных форм. ...
Монография посвящена рыбам рода гольцы Salvelinus семейства лососевые
Salmonidae отряда Salmoniformes. В первой части книги представлен аналитический обзор современных представлений о возникновении основных видов гольцов, описаны механизмы их внутриозерной диверсификации. Общие вопросы возникновения современной мозаики разнообразия рассматриваются как внутри рода, так и с привлечением примеров из других групп рыб. Во второй части детально описано и проиллюстрировано современное разнообразие гольцов азиатской части Северной Пацифики – исторического центра эволюционной радиации группы. Значительная часть представленных материалов является оригинальной, получена авторами в ходе многолетних исследований и публикуется впервые. Предложенная схема описания гольцов структурирует современные знания о разнообразии внутри рода и путях формирования разнообразия в отдельно взятом регионе, что позволяет не только специалистам, но и широкому кругу заинтересованных читателей получить актуальные представления об этой сложнейшей и интереснейшей группе лососевых рыб.
