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Houting
The houting (''Coregonus oxyrhynchus'') is a European, allegedly extinct species of whitefish in the family Salmonidae. It is native to the estuaries and rivers draining to the North Sea. The houting is distinguishable from other ''Coregonus'' taxa by having a long, pointed snout, an inferior mouth and a different number of gill rakers.Freyhof, J. and C. Schöter. 2005. The houting Coregonus oxyrinchus (L.)(Salmoniformes: Coregonidae), a globally extinct species from the North Sea basin. Journal of Fish Biology 67:3, 713–729.Schöter C., 2002. Revision der Schnäpel und Großen Maränen des Nordseeund südwestlichen Ostseeraumes (Teleostei: Coregonidae). Diplomarbeit, Rheinischen Friedrich-Wilhelms-Universität, Bonn. The houting once occurred in Belgium, France, Germany, the Netherlands and England.Freyhof, J. & Kottelat, M. 2008. Coregonus oxyrinchus. In: IUCN 2008. 2008 IUCN Red List of Threatened Species. . Downloaded on 21 December 2008. Controversial status There is how ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Wadden Sea
The Wadden Sea ( nl, Waddenzee ; german: Wattenmeer; nds, Wattensee or ; da, Vadehavet; fy, Waadsee, longname=yes; frr, di Heef) is an intertidal zone in the southeastern part of the North Sea. It lies between the coast of northwestern continental Europe and the range of low-lying Frisian Islands, forming a shallow body of water with tidal flats and wetlands. It has a high biological diversity and is an important area for both breeding and migrating birds. In 2009, the Dutch and German parts of the Wadden Sea were inscribed on UNESCO's World Heritage List and the Danish part was added in June 2014. The Wadden Sea stretches from Den Helder, in the northwest of the Netherlands, past the great river estuaries of Germany to its northern boundary at Skallingen in Denmark along a total coastline of some and a total area of about . Within the Netherlands, it is bounded from the IJsselmeer by the Afsluitdijk. Historically, the coastal regions were often subjected to large floods, r ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Coregonus
''Coregonus'' is a diverse genus of fish in the salmon family (Salmonidae). The ''Coregonus'' species are known as whitefishes. The genus contains at least 68 described extant taxa, but the true number of species is a matter of debate. The type species of the genus is '' Coregonus lavaretus''. Most ''Coregonus'' species inhabit lakes and rivers, and several species, including the Arctic cisco (''C. autumnalis''), the Bering cisco (''C. laurettae''), and the least cisco (''C. sardinella'') are anadromous, moving between salt water and fresh water. Many whitefish species or ecotypes, especially from the Great Lakes and the Alpine lakes of Europe, have gone extinct over the past century or are endangered. Among 12 freshwater fish considered extinct in Europe, 6 are ''Coregonus''. All ''Coregonus'' species are protected under appendix III of the Bern Convention. Taxonomy Phylogenetic evidence indicates that the most basal member of the genus is the highly endang ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Local Extinction
Local extinction, also known as extirpation, refers to a species (or other taxon) of plant or animal that ceases to exist in a chosen geographic area of study, though it still exists elsewhere. Local extinctions are contrasted with global extinctions. Local extinctions mark a change in the ecology of an area. In recent times, local extinction has sometimes been followed by a replacement of the species taken from other locations; wolf reintroduction is an example of this. The term "local extinction" is highly vernacular. The more proper biological term is ''extirpation''. Discussion Glaciation can lead to local extinction. This was the case during the Pleistocene glaciation event in North America. During this period, most of the native North American species of earthworm were killed in places covered by glaciation. This left them open for colonization by European earthworms brought over in soil from Europe. Species naturally become extirpated from islands over time. The number ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
The LIFE Programme
The LIFE programme (French: L’Instrument Financier pour l’Environnement) is the European Union's funding instrument for the environment and climate action. The general objective of LIFE is to contribute to the implementation, updating and development of EU environmental and climate policy and legislation by co-financing projects with European added value. LIFE began in 1992 and to date there have been five phases of the programme (LIFE I: 1992–1995, LIFE II: 1996–1999, LIFE III: 2000–2006, LIFE+: 2007–2013 and LIFE 2014–2020). During this period, LIFE has co-financed some 4600 projects across the EU, with a total contribution of approximately 6.5 billion Euros to the protection of the environment and of climate. For the next phase of the programme (2021–2027) the European Commission proposed to raise the budget to 5.45 billion Euro. The European Commission ( DG Environment and DG Climate Action) manages the LIFE programme. The commission has delegated the implem ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Elbe
The Elbe (; cs, Labe ; nds, Ilv or ''Elv''; Upper and dsb, Łobjo) is one of the major rivers of Central Europe. It rises in the Giant Mountains of the northern Czech Republic before traversing much of Bohemia (western half of the Czech Republic), then Germany and flowing into the North Sea at Cuxhaven, northwest of Hamburg. Its total length is . The Elbe's major tributaries include the rivers Vltava, Saale, Havel, Mulde, Schwarze Elster, and Ohře. The Elbe river basin, comprising the Elbe and its tributaries, has a catchment area of , the twelfth largest in Europe. The basin spans four countries, however it lies almost entirely just in two of them, Germany (65.5%) and the Czech Republic (33.7%, covering about two thirds of the state's territory). Marginally, the basin stretches also to Austria (0.6%) and Poland (0.2%). The Elbe catchment area is inhabited by 24.4 million people, the biggest cities within are Berlin, Hamburg, Prague, Dresden and Leipzig. Etymology Firs ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rhine
), Surselva, Graubünden, Switzerland , source1_coordinates= , source1_elevation = , source2 = Rein Posteriur/Hinterrhein , source2_location = Paradies Glacier, Graubünden, Switzerland , source2_coordinates= , source2_elevation = , source_confluence = Reichenau , source_confluence_location = Tamins, Graubünden, Switzerland , source_confluence_coordinates= , source_confluence_elevation = , mouth = North Sea , mouth_location = Netherlands , mouth_coordinates = , mouth_elevation = , progression = , river_system = , basin_size = , tributaries_left = , tributaries_right = , custom_label = , custom_data = , extra = The Rhine ; french: Rhin ; nl, Rijn ; wa, Rén ; li, Rien; rm, label= Sursilvan, Rein, rm, label= Sutsilvan and Surmiran, Ragn, rm, label=Rumantsch Grischun, Vallader and Puter, Rain; it, Reno ; gsw, Rhi(n), inclu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Introgression
Introgression, also known as introgressive hybridization, in genetics is the transfer of genetic material from one species into the gene pool of another by the repeated backcrossing of an interspecific hybrid with one of its parent species. Introgression is a long-term process, even when artificial; it may take many hybrid generations before significant backcrossing occurs. This process is distinct from most forms of gene flow in that it occurs between two populations of different species, rather than two populations of the same species. Introgression also differs from simple hybridization. Simple hybridization results in a relatively even mixture; gene and allele frequencies in the first generation will be a uniform mix of two parental species, such as that observed in mules. Introgression, on the other hand, results in a complex, highly variable mixture of genes, and may only involve a minimal percentage of the donor genome. Definition Introgression or introgressive hybri ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hybrid (biology)
In biology, a hybrid is the offspring resulting from combining the qualities of two organisms of different breeds, varieties, species or genera through sexual reproduction. Hybrids are not always intermediates between their parents (such as in blending inheritance), but can show hybrid vigor, sometimes growing larger or taller than either parent. The concept of a hybrid is interpreted differently in animal and plant breeding, where there is interest in the individual parentage. In genetics, attention is focused on the numbers of chromosomes. In taxonomy, a key question is how closely related the parent species are. Species are reproductively isolated by strong barriers to hybridisation, which include genetic and morphological differences, differing times of fertility, mating behaviors and cues, and physiological rejection of sperm cells or the developing embryo. Some act before fertilization and others after it. Similar barriers exist in plants, with differences in flowering tim ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Evolutionarily Significant Unit
An evolutionarily significant unit (ESU) is a population of organisms that is considered distinct for purposes of conservation. Delineating ESUs is important when considering conservation action. This term can apply to any species, subspecies, geographic race, or population. Often the term "species" is used rather than ESU, even when an ESU is more technically considered a subspecies or variety rather than a biological species proper. In marine animals the term "stock" is often used as well. Definition Definitions of an ESU generally include at least one of the following criteria:Jeffrey Conner, Daniel Hartl. ''A Primer of Ecological Genetics''. 2004, # Current geographic separation, # Genetic differentiation at neutral markers among related ESUs caused by past restriction of gene flow, or # Locally adapted phenotypic traits caused by differences in selection. Criterion 2 considers the gene flow between populations, measured by FST. A high degree of differentiation between tw ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Baltic Sea
The Baltic Sea is an arm of the Atlantic Ocean that is enclosed by Denmark, Estonia, Finland, Germany, Latvia, Lithuania, Poland, Russia, Sweden and the North and Central European Plain. The sea stretches from 53°N to 66°N latitude and from 10°E to 30°E longitude. A marginal sea of the Atlantic, with limited water exchange between the two water bodies, the Baltic Sea drains through the Danish Straits into the Kattegat by way of the Øresund, Great Belt and Little Belt. It includes the Gulf of Bothnia, the Bay of Bothnia, the Gulf of Finland, the Gulf of Riga and the Bay of Gdańsk. The " Baltic Proper" is bordered on its northern edge, at latitude 60°N, by Åland and the Gulf of Bothnia, on its northeastern edge by the Gulf of Finland, on its eastern edge by the Gulf of Riga, and in the west by the Swedish part of the southern Scandinavian Peninsula. The Baltic Sea is connected by artificial waterways to the White Sea via the White Sea–Baltic Canal and to the German ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Coregonus Maraena
''Coregonus maraena'', referred to in English as the maraene, maraena whitefish or the whitefish, is a whitefish of the family Salmonidae that occurs in the Baltic Sea basin - in the sea itself and the inflowing rivers, and in several lakes as landlocked populations. It is found in Denmark, Estonia, Finland, Germany, Latvia, Lithuania, Netherlands, Norway, Poland, Slovakia (Štrbské pleso), Russia and Sweden. As of 2013, it has been listed as a vulnerable species by the IUCN and as endangered by HELCOM. It is an extremely important fish within the Baltic Sea ecosystem, both for population equilibrium and for the local diets of the surrounding human population. Due to a variety of factors, mostly overfishing, the maraena’s population dwindled to near-extinction levels. Thus, rampant repopulation was enacted to preserve this important fish. In the Baltic basin countries, this species has traditionally been known as '' Coregonus lavaretus'' (the common whitefish). The name ''Co ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Species Complex
In biology, a species complex is a group of closely related organisms that are so similar in appearance and other features that the boundaries between them are often unclear. The taxa in the complex may be able to hybridize readily with each other, further blurring any distinctions. Terms that are sometimes used synonymously but have more precise meanings are cryptic species for two or more species hidden under one species name, sibling species for two (or more) species that are each other's closest relative, and species flock for a group of closely related species that live in the same habitat. As informal taxonomic ranks, species group, species aggregate, macrospecies, and superspecies are also in use. Two or more taxa that were once considered conspecific (of the same species) may later be subdivided into infraspecific taxa (taxa within a species, such as bacterial strains or plant varieties), that is complex but it is not a species complex. A species complex is in most cas ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
