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Gravenche
The gravenche (''Coregonus hiemalis''), also known as the Lake Geneva whitefish or the little fera, is a presumably extinct freshwater fish from Lake Geneva in Switzerland and France. Description The gravenche was a species of freshwater whitefish (Coregoninae) that reached a length between .Christian TrépeyCorégone (Féra - Palée)www.plongee-passion.ch The status of the gravenche is disputed because there are no specimens in museums. While Emile Dottrens described it as subspecies of the common whitefish ''Coregonus lavaretus'' in 1958, other experts like Maurice Kottelat regarded it as a full species endemic to Lake Geneva.Maurice Kottelat: ''European Freshwater Fisches. An heuristic checklist of the freshwater fishes of Europe (exclusive of former USSR), with an introduction for non - systematists and comments on nomenclature and conservation''; Biologia: Section Zoology vol. 52/5, Slovak Academic Press, Bratislava 1997, Kottelat, M. & Freyhof, J. (2007). Handbook of Eur ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Louis Jurine
Louis Jurine (; 6 February 1751 – 20 October 1819) was a Swiss physician, surgeon and naturalist mainly interested in entomology. He lived in Geneva. Surgeon He studied surgery in Paris and quickly acquired a great reputation for his expertise in medicine and natural history beyond that which he had in Geneva. He taught courses in anatomy and surgery at the Société des Arts in Geneva and was made honorary professor of zoology at the Academy (today: University of Geneva). He also founded a maternity hospice in 1807 and was awarded prizes for his work on the gasses of the human body, artificial feeding of infants, and pectoral angina. Naturalist Upon learning of Spallanzani's experiments with bats, in which Spallanzani showed that bats do not rely on sight when navigating in darkness, Jurine conducted a series of experiments from which he concluded that bats use sound to navigate in darkness.See: * Peschier (1798 "Extraits des expériences de Jurine sur les chauve-souris qu' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Coregonus Fera
''Coregonus fera'', commonly called the ''true fera'', is a presumed extinct freshwater fish from Lake Geneva in Switzerland and France. Description The fera is a species of freshwater whitefish that reached a length between 35 and 40 centimetres. It is a member of the common whitefish complex (''Coregonus lavaretus'' sensu lato). The identity of the fera is disputed. In 1950 Emile Dottrens described ''Coregonus fera'' as native to both Lake Geneva and Lake Constance. The coregonines from Lake Constance were named ''Sandfelchen''. In 1997 Maurice Kottelat made a revision and used the name ''Coregonus fera'' for the Geneva fera and '' Coregonus arenicolus'' for the''Sandfelchen''. The common name fera is still also used for fish that continue to live in Lake Geneva, but it now refers to the introduced ''Coregonus palaea''.Maurice Kottelat & Jörg Freyhof (2008''Coregonus fera'' The IUCN Red List of Threatened Species v. 2015-4 Biology The true fera was a benthopelagic freshwat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Extinct Animals Of Europe
Extinction is the termination of a kind of organism or of a group of kinds (taxon), usually a species. The moment of extinction is generally considered to be the death of the last individual of the species, although the capacity to breed and recover may have been lost before this point. Because a species' potential range may be very large, determining this moment is difficult, and is usually done retrospectively. This difficulty leads to phenomena such as Lazarus taxa, where a species presumed extinct abruptly "reappears" (typically in the fossil record) after a period of apparent absence. More than 99% of all species that ever lived on Earth, amounting to over five billion species, are estimated to have died out. It is estimated that there are currently around 8.7 million species of eukaryote globally, and possibly many times more if microorganisms, like bacteria, are included. Notable extinct animal species include non-avian dinosaurs, saber-toothed cats, dodos, m ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cold Water Fish
Coldwater fish can have different meanings in different contexts. In the context of aquariums, it refers to fish species that do not require a heater to remain within tolerable temperatures in a typical indoor aquarium. However, most or all ornamental fish species are able to tolerate temperatures as low as or lower than room temperature, with most stenothermic tropical species having critical thermal minimums of around 10-12 °C. Although these fish are capable of surviving in unheated aquaria, their temperature preferences may vary. For example, koi, goldfish, and pond loaches are commonly considered to be cold-water fish because of their ability to survive at very low temperatures, but their temperature preferences and/or physiological optimal temperatures are 32 °C (90 °F), 24-31 °C (75-88 °F), and 26-28 °C (79-82 °F), respectively. Because many of the ornamental fish considered to be “coldwater fish” are more accurately eurythermal ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lake Fish
A lake is an area filled with water, localized in a basin, surrounded by land, and distinct from any river or other outlet that serves to feed or drain the lake. Lakes lie on land and are not part of the ocean, although, like the much larger oceans, they do form part of the Earth's water cycle. Lakes are distinct from lagoons, which are generally coastal parts of the ocean. Lakes are typically larger and deeper than ponds, which also lie on land, though there are no official or scientific definitions. Lakes can be contrasted with rivers or streams, which usually flow in a channel on land. Most lakes are fed and drained by rivers and streams. Natural lakes are generally found in mountainous areas, rift zones, and areas with ongoing glaciation. Other lakes are found in endorheic basins or along the courses of mature rivers, where a river channel has widened into a basin. Some parts of the world have many lakes formed by the chaotic drainage patterns left over from the last ice ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Freshwater Fish Of Europe
Fresh water or freshwater is any naturally occurring liquid or frozen water containing low concentrations of dissolved salts and other total dissolved solids. Although the term specifically excludes seawater and brackish water, it does include non- salty mineral-rich waters such as chalybeate springs. Fresh water may encompass frozen and meltwater in ice sheets, ice caps, glaciers, snowfields and icebergs, natural precipitations such as rainfall, snowfall, hail/ sleet and graupel, and surface runoffs that form inland bodies of water such as wetlands, ponds, lakes, rivers, streams, as well as groundwater contained in aquifers, subterranean rivers and lakes. Fresh water is the water resource that is of the most and immediate use to humans. Water is critical to the survival of all living organisms. Many organisms can thrive on salt water, but the great majority of higher plants and most insects, amphibians, reptiles, mammals and birds need fresh water to survive. Fresh water i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fish Described In 1825
Fish are aquatic, craniate, gill-bearing animals that lack limbs with digits. Included in this definition are the living hagfish, lampreys, and cartilaginous and bony fish as well as various extinct related groups. Approximately 95% of living fish species are ray-finned fish, belonging to the class Actinopterygii, with around 99% of those being teleosts. The earliest organisms that can be classified as fish were soft-bodied chordates that first appeared during the Cambrian period. Although they lacked a true spine, they possessed notochords which allowed them to be more agile than their invertebrate counterparts. Fish would continue to evolve through the Paleozoic era, diversifying into a wide variety of forms. Many fish of the Paleozoic developed external armor that protected them from predators. The first fish with jaws appeared in the Silurian period, after which many (such as sharks) became formidable marine predators rather than just the prey of arthropods. Mos ... [...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] |
IUCN Red List Of Threatened Species
The International Union for Conservation of Nature (IUCN) Red List of Threatened Species, also known as the IUCN Red List or Red Data Book, founded in 1964, is the world's most comprehensive inventory of the global conservation status of biological species. It uses a set of precise criteria to evaluate the extinction risk of thousands of species and subspecies. These criteria are relevant to all species and all regions of the world. With its strong scientific base, the IUCN Red List is recognized as the most authoritative guide to the status of biological diversity. A series of Regional Red Lists are produced by countries or organizations, which assess the risk of extinction to species within a political management unit. The aim of the International Union for Conservation of Nature, IUCN Red List is to convey the urgency of conservation issues to the public and policy makers, as well as help the international community to reduce species extinction. According to International Unio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Eutrophication
Eutrophication is the process by which an entire body of water, or parts of it, becomes progressively enriched with minerals and nutrients, particularly nitrogen and phosphorus. It has also been defined as "nutrient-induced increase in phytoplankton productivity". Water bodies with very low nutrient levels are termed oligotrophic and those with moderate nutrient levels are termed mesotrophic. Advanced eutrophication may also be referred to as dystrophic and hypertrophic conditions. Eutrophication can affect freshwater or salt water systems. In freshwater ecosystems it is almost always caused by excess phosphorus. In coastal waters on the other hand, the main contributing nutrient is more likely to be nitrogen, or nitrogen and phosphorus together. This depends on the location and other factors. When occurring naturally, eutrophication is a very slow process in which nutrients, especially phosphorus compounds and organic matter, accumulate in water bodies. These nutrients deriv ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Overfishing
Overfishing is the removal of a species of fish (i.e. fishing) from a body of water at a rate greater than that the species can replenish its population naturally (i.e. the overexploitation of the fishery's existing fish stock), resulting in the species becoming increasingly underpopulated in that area. Overfishing can occur in water bodies of any sizes, such as ponds, wetlands, rivers, lakes or oceans, and can result in resource depletion, reduced biological growth rates and low biomass levels. Sustained overfishing can lead to critical depensation, where the fish population is no longer able to sustain itself. Some forms of overfishing, such as the overfishing of sharks, has led to the upset of entire marine ecosystems. Types of overfishing include: growth overfishing, recruitment overfishing, ecosystem overfishing. The ability of a fishery to recover from overfishing depends on whether its overall carrying capacity and the variety of ecological conditions are suitable for t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Spawn (biology)
Spawn is the Egg cell, eggs and Spermatozoa, sperm released or deposited into water by aquatic animals. As a verb, ''to spawn'' refers to the process of releasing the eggs and sperm, and the act of both sexes is called spawning. Most aquatic animals, except for aquatic mammals and marine reptile, reptiles, reproduce through the process of spawning. Spawn consists of the reproductive cells (gametes) of many aquatic animals, some of which will become fertilized and produce offspring. The process of spawning typically involves females releasing Ovum, ova (unfertilized eggs) into the water, often in large quantities, while males simultaneously or sequentially release spermatozoa (milt) to fertilize the eggs. Most fish reproduce by spawning, as do most other aquatic animals, including crustaceans such as crabs and shrimps, molluscs such as oysters and squid, echinoderms such as sea urchins and sea cucumbers, amphibians such as frogs and newts, aquatic insects such as mayflies and mos ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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