|
Stenodus Leucichthys
''Stenodus leucichthys'' is a species of freshwater whitefish in the family Salmonidae. In the strict sense its natural distribution is restricted to the Caspian Sea basin, and it is known as beloribitsa (literally meaning "the fish that is white" in Russian). The beloribitsa is now considered extinct in the wild, but survives in cultured stocks. The nelma (''Stenodus nelma''), a more widespread species of Eurasian and North America, is sometimes considered its subspecies. Systematics Alternatively, the name ''Stenodus leucichtys'' has been used in a broader sense, referring to a widespread species composed of two subspecies. In addition to the landlocked subspecies ''Stenodus leucichthys leucichthys'', it comprises the nelma, ''Stenodus leucichthys nelma'' (Pallas, 1773) which lives in Eurasian and North American rivers of the Arctic basin. Nelma, also known as the sheefish or inconnu, is currently often considered as a distinct species ''Stenodus nelma''. At a higher level, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Johann Anton Güldenstädt
Johann Anton Güldenstädt (26 April 1745 in Riga, Latvia – 23 March 1781 in St. Petersburg, Russia) was a Baltic German natural history, naturalist and explorer in Russian service. Güldenstädt lost both his parents early, and from 1763 onwards studied pharmacy, botany and natural history in Berlin. At the age of 22, he obtained his doctorate in medicine at the Viadrina European University, University of Frankfurt in 1767. In the following year, he joined the Russian Academy of Sciences, Russian Imperial Academy of Sciences' expedition sent by Catherine II of Russia to explore the Russian empire's southern frontier. Güldenstädt travelled through Ukraine and the Astrakhan Oblast, Astrakhan region, as well as the northern Caucasus and Georgia (country), Georgia, both of which were almost entirely beyond the borders of the Russian empire. In March 1775 he returned to St Petersburg. The results of the expedition and Güldenstädt's edited expedition journal were published after ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dorsal Fin
A dorsal fin is a fin located on the back of most marine and freshwater vertebrates within various taxa of the animal kingdom. Many species of animals possessing dorsal fins are not particularly closely related to each other, though through convergent evolution they have independently evolved external superficial fish-like body plans adapted to their marine environments, including most numerously fish, but also mammals such as cetaceans (whales, dolphins, and porpoises), and even extinct ancient marine reptiles such as various known species of ichthyosaurs. Most species have only one dorsal fin, but some have two or three. Wildlife biologists often use the distinctive nicks and wear patterns which develop on the dorsal fins of large cetaceans to identify individuals in the field. The bony or cartilaginous bones that support the base of the dorsal fin in fish are called ''pterygiophores''. Functions The main purpose of the dorsal fin is to stabilize the animal against rollin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Freshwater Fish Of The Arctic
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] |
Stenodus
''Stenodus'' is a genus of large-sized whitefish in the family Salmonidae. It consists of two species; one of them (beloribitsa) is extinct in wild. The two species have alternatively been considered subspecies of the single species ''Stenodus leucichthys''. Species * ''Stenodus leucichthys'' — beloribitsa: the Caspian Sea basin * ''Stenodus nelma'' — nelma, sheefish or inconnu: rivers of the Arctic basin. Systematics The genus ''Stenodus'' is distinctive from other whitefishes due to its size and specialized predator morphology; however, evidence of independence from the broader freshwater whitefish genus ''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 ...'' is not clearly evident. References Sources * Ray-finned fish genera Taxa named by John R ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
IUCN
The International Union for Conservation of Nature (IUCN; officially International Union for Conservation of Nature and Natural Resources) is an international organization working in the field of nature conservation and sustainable use of natural resources. It is involved in data gathering and analysis, research, field projects, advocacy, and education. IUCN's mission is to "influence, encourage and assist societies throughout the world to conserve nature and to ensure that any use of natural resources is equitable and ecologically sustainable". Over the past decades, IUCN has widened its focus beyond conservation ecology and now incorporates issues related to sustainable development in its projects. IUCN does not itself aim to mobilize the public in support of nature conservation. It tries to influence the actions of governments, business and other stakeholders by providing information and advice and through building partnerships. The organization is best known to the wider ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Terek River
The Terek (; , Tiyrk; , Tərč; , ; , ; , ''Terk''; , ; , ) is a major river in the Northern Caucasus. It originates in the Mtskheta-Mtianeti region of Georgia (country), Georgia and flows through North Caucasus region of Russia into the Caspian Sea. It rises near the juncture of Caucasus Mountains, the Greater Caucasus Mountain Range and the Khokh Range, to the southwest of Mount Kazbek, winding north in a white torrent between the town of Stepantsminda and the village of Gergeti toward the Russian region North Ossetia and the city of Vladikavkaz. It turns east to flow through Chechnya and Dagestan before Water divide, dividing into two branches which empty into the Caspian Sea. Below the city of Kizlyar it forms a swampy river delta around wide. The river is a key natural asset in the region, providing irrigation and hydroelectric power in its upper reaches. The main cities on the Terek include Vladikavkaz, Mozdok, and Kizlyar. Several minor Hydroelectricity, hydroelectric ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ural (river)
The Ural (russian: Урал, ), known before 1775 as Yaik (russian: Яик, ba, Яйыҡ, translit=Yayıq, ; kk, Жайық, translit=Jaiyq, ), is a river flowing through Russia and Kazakhstan in the continental border between Europe and Asia. It originates in the southern Ural Mountains and discharges into the Caspian Sea. At , it is the third-longest river in Europe after the Volga and the Danube, and the 18th-longest river in Asia. The Ural is conventionally considered part of the boundary between the continents of Europe and Asia. The Ural arises near Mount Kruglaya in the Ural Mountains, flows south parallel and west of the north-flowing Tobol, through Magnitogorsk, and around the southern end of the Urals, through Orsk where it turns west for about , to Orenburg, where the river Sakmara joins. From Orenburg it continues west, passing into Kazakhstan, then turning south again at Oral, and meandering through a broad flat plain until it reaches the Caspian a few miles be ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Volga
The Volga (; russian: Во́лга, a=Ru-Волга.ogg, p=ˈvoɫɡə) is the List of rivers of Europe#Rivers of Europe by length, longest river in Europe. Situated in Russia, it flows through Central Russia to Southern Russia and into the Caspian Sea. The Volga has a length of , and a catchment area of «Река Волга» , Russian State Water Registry which is more than twice the size of Ukraine. It is also Europe's largest river in terms of average discharge (hydrology), discharge at delta – between and – and of drainage basin. It is widely regarded as the Rivers in Russia, national river of Russia. The hypothetical old Russian state, the Rus' Khaganate, arose along the Volga . Historically, the river served as an important meeting place of various Eurasian civilizations. The river flows in Russia through forests, Fo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Predator
Predation is a biological interaction where one organism, the predator, kills and eats another organism, its prey. It is one of a family of common feeding behaviours that includes parasitism and micropredation (which usually do not kill the host) and parasitoidism (which always does, eventually). It is distinct from scavenging on dead prey, though many predators also scavenge; it overlaps with herbivory, as seed predators and destructive frugivores are predators. Predators may actively search for or pursue prey or wait for it, often concealed. When prey is detected, the predator assesses whether to attack it. This may involve ambush or pursuit predation, sometimes after stalking the prey. If the attack is successful, the predator kills the prey, removes any inedible parts like the shell or spines, and eats it. Predators are adapted and often highly specialized for hunting, with acute senses such as vision, hearing, or smell. Many predatory animals, both vertebrate and i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Plankton
Plankton are the diverse collection of organisms found in Hydrosphere, water (or atmosphere, air) that are unable to propel themselves against a Ocean current, current (or wind). The individual organisms constituting plankton are called plankters. In the ocean, they provide a crucial source of food to many small and large aquatic organisms, such as bivalves, fish and whales. Marine plankton include bacteria, archaea, algae, protozoa and drifting or floating animals that inhabit the saltwater of oceans and the brackish waters of estuaries. Freshwater plankton are similar to marine plankton, but are found in the freshwaters of lakes and rivers. Plankton are usually thought of as inhabiting water, but there are also airborne versions, the aeroplankton, that live part of their lives drifting in the atmosphere. These include plant spores, pollen and wind-scattered seeds, as well as microorganisms swept into the air from terrestrial dust storms and oceanic plankton swept into the air ... [...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] |
Freshwater Whitefish
The freshwater whitefish are fishes of the subfamily Coregoninae, which contains whitefishes (both freshwater and anadromous) and ciscoes, and is one of three subfamilies in the salmon family Salmonidae. Apart from the subfamily Coregoninae, the family Salmonidae includes the salmon, trout, and char species of the subfamily Salmoninae, and grayling species of the subfamily Thymallinae. Freshwater whitefish are distributed mainly in relatively cool waters throughout the northern parts of the Northern Hemisphere. The Coregoninae subfamily consists of three nominal genera: *''Coregonus'' Linnaeus, 1758 – whitefishes and ciscoes, which according to some authors number more than 60 species. There are differing opinions on the classification of some species within the genus and the overall number of species. Some species in Arctic regions of Asia and North America forage in marine waters. *''Prosopium'' Jordan, 1878 – round whitefishes, which includes six species, three of which ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
_with_its_prey.jpg "Click for more on -> Predator")
