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European River Zonation
The classification of European rivers comes from the fish fauna found in them. Changes in taxonomic composition relate to physical and chemical changes that occur longitudinally. Zonation (from headwater to estuary) Trout zone This zone has a characteristic steep gradient, fast flowing water and cool temperature. The fast flow rate causes turbulence which keeps the water well oxygenated. Fish species found in this zone usually lay adhesive eggs that can stick to the substrate, this is to help prevent eggs being carried down stream by the water flow. Characteristic fish species are: * Brown trout (''Salmo trutta'') * Atlantic salmon (''Salmo salar'') * Bullhead (''Cottus gobio'') * Loach (''Barbatula barbatula'') Grayling zone Similar in physical characteristics to the Trout zone, although the temperature is usually slightly higher. Fish species in this zone also lay adhesive eggs. Characteristic fish species include all of the above species, with the addition of; * Gray ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
List Of Rivers Of Europe
This article lists the principal rivers of Europe with their main tributaries. Scope The border of Europe and Asia is here defined as from the Kara Sea, along the Ural Mountains and Ural River to the Caspian Sea. While the crest of the Caucasus Mountains is the geographical border with Asia in the south, Georgia, and to a lesser extent Armenia and Azerbaijan, are politically and culturally often associated with Europe; rivers in these countries are therefore included. The list is at the outset limited to those rivers that are at least 250 km long from the most distant source, have a drainage basin (catchment area, watershed) of at least , or have a mean discharge (volume, flow) of at least . Also included are a number of rivers (currently 47) that do not meet these criteria, but are very well known and/or nearly make the mark. Examples of these are the Arno, Ruhr, Saar, and Clyde. See the lists of rivers for individual countries linked to at the bottom of the page for sm ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Photosynthesis
Photosynthesis is a process used by plants and other organisms to convert light energy into chemical energy that, through cellular respiration, can later be released to fuel the organism's activities. Some of this chemical energy is stored in carbohydrate molecules, such as sugars and starches, which are synthesized from carbon dioxide and water – hence the name ''photosynthesis'', from the Greek ''phōs'' (), "light", and ''synthesis'' (), "putting together". Most plants, algae, and cyanobacteria perform photosynthesis; such organisms are called photoautotrophs. Photosynthesis is largely responsible for producing and maintaining the oxygen content of the Earth's atmosphere, and supplies most of the energy necessary for life on Earth. Although photosynthesis is performed differently by different species, the process always begins when energy from light is absorbed by proteins called reaction centers that contain green chlorophyll (and other colored) pigments/chromoph ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tench
The tench or doctor fish (''Tinca tinca'') is a fresh- and brackish-water fish of the order Cypriniformes found throughout Eurasia from Western Europe including the British Isles east into Asia as far as the Ob and Yenisei Rivers. It is also found in Lake Baikal. It normally inhabits slow-moving freshwater habitats, particularly lakes and lowland rivers.B. Whitton (1982). ''Rivers, Lakes and Marshes'' p 163. Hodder & Staughton, London. Taxonomy The tench was formerly classified in the subfamily Leuciscinae with other Eurasian minnows, but more recent phylogenetic studies have supported it belonging to its own family Tincidae. Ecology The tench is most often found in still waters with a clay or muddy substrate and abundant vegetation.A. F. Magri MacMahon (1946). ''Fishlore'', pp 156-158. Pelican Books. This species is rare in clear waters across stony substrate, and is absent altogether from fast-flowing streams. It tolerates water with a low oxygen concentration, being ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bream
Bream ( ) are species of freshwater and marine fish belonging to a variety of genera including '' Abramis'' (e.g., ''A. brama'', the common bream), '' Acanthopagrus'', ''Argyrops'', '' Blicca'', '' Brama'', '' Chilotilapia'', ''Etelis'', '' Lepomis'', '' Gymnocranius'', ''Lethrinus'', ''Nemipterus'', '' Pharyngochromis'', ''Rhabdosargus'', '' Scolopsis'', or ''Serranochromis''. Although species from all of these genera are called "bream", the term does not imply a degree of relatedness between them. Fish termed "bream" tend to be narrow, deep-bodied species. The name is a derivation of the Middle English word ''breme'', of Old French origin. The term sea bream is sometimes used for gilt-head bream (''Sparus aurata''), (''orata'' in Italy, ''dorada'' in Spain) or porgies (both family Sparidae) or pomfrets (family Bramidae) . See also * Porgie fishing * Bluegill The bluegill (''Lepomis macrochirus''), sometimes referred to as "bream", "brim", "sunny", or "copper nose" ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Turbid
Turbidity is the cloudiness or haziness of a fluid caused by large numbers of individual particles that are generally invisible to the naked eye, similar to smoke in air. The measurement of turbidity is a key test of water quality. Fluids can contain suspended solid matter consisting of particles of many different sizes. While some suspended material will be large enough and heavy enough to settle rapidly to the bottom of the container if a liquid sample is left to stand (the settable solids), very small particles will settle only very slowly or not at all if the sample is regularly agitated or the particles are colloidal. These small solid particles cause the liquid to appear turbid. Turbidity (or haze) is also applied to transparent solids such as glass or plastic. In plastic production, haze is defined as the percentage of light that is deflected more than 2.5° from the incoming light direction. Causes and effects Turbidity in open water may be caused by growth of phyto ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
European Eel
The European eel (''Anguilla anguilla'') is a species of eel, a snake-like, catadromous fish. They are normally around and rarely reach more than , but can reach a length of up to in exceptional cases. Eels have been important sources of food both as adults (including jellied eels of East London) and as glass eels. Glass-eel fishing using basket traps has been of significant economic value in many river estuaries on the western seaboard of Europe. While the species' lifespan in the wild has not been determined, captive specimens have lived over 80 years. A specimen known as "the Brantevik Eel" lived for 155 years in the well of a family home in Brantevik, a fishing village in southern Sweden. Conservation status The European eel is a critically endangered species. Since the 1970s, the numbers of eels reaching Europe is thought to have declined by around 90% (possibly even 98%). Contributing factors include overfishing, parasites such as '' Anguillicola crassus'', b ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Northern Pike
The northern pike (''Esox lucius'') is a species of carnivorous fish of the genus ''Esox'' (the pikes). They are typical of brackish and fresh waters of the Northern Hemisphere (''i.e.'' holarctic in distribution). They are known simply as a pike in Britain, Ireland, and most of Eastern Europe, Canada and the United States. Pike can grow to a relatively large size: the average length is about , with maximum recorded lengths of up to and published weights of . The IGFA currently recognizes a pike caught by Lothar Louis on Greffern Lake, Germany, on 16 October 1986, as the all-tackle world-record northern pike. Northern pike grow to larger sizes in Eurasia than in North America, and typically grow to larger sizes in coastal than inland regions of Eurasia. Etymology The northern pike gets its common name from its resemblance to the pole-weapon known as the pike (from the Middle English for 'pointed'). Various other unofficial trivial names are common pike, Lakes pike, great ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
European Perch
The European perch (''Perca fluviatilis''), also known as the common perch, redfin perch, big-scaled redfin, English perch, Euro perch, Eurasian perch, Eurasian river perch, Hatch, poor man’s rockfish or in Anglophone parts of Europe, simply the perch, is a predatory species of the freshwater perch native to Europe and northern Asia. The species is a popular quarry for anglers, and has been widely introduced beyond its native area, into Australia, New Zealand and South Africa. They have caused substantial damage to native fish populations in Australia and have been proclaimed a noxious species in New South Wales. Description European perch are greenish with red pelvic, anal and caudal fins. They have five to eight dark vertical bars on their sides. When the perch grows larger, a hump grows between its head and dorsal fin. European perch can vary greatly in size between bodies of water. They can live for up to 22 years, and older perch are often much larger than average; ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Common Rudd
The common rudd (''Scardinius erythrophthalmus'') is a bentho-pelagic freshwater fish, widely spread in Europe and middle Asia, around the basins of the North, Baltic, Black, Caspian and Aral seas. Identification Morphologically, this species is very similar to the roach ('' Rutilus rutilus''), with which it can be easily confused. It can be identified by the yellow eye colour. The eye of the roach has a big red spot above the pupil, that can be more or less conspicuous. The rudd has an upturned mouth allowing it to feed easily at the top of the water. The placement of the dorsal fin is more to the rear which is even visible in very young fish. There are normally only one or two scales between the tip of the pelvic fins and the anal fins, while on the roach there are five. Also the skin of the rudd is yellowish green, while the roach is bluish on the flanks. Also the upturned mouth is visible even in young fish. Furthermore, the rudd's number of soft rays in the dorsal fin (8 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Barbel (fish Species)
Barbels are group of small carp-like freshwater fish, almost all of the genus ''Barbus''. They are usually found in gravel and rocky-bottomed slow-flowing waters with high dissolved oxygen content. A typical adult barbel can range from 25 to 100 cm in length and weigh between 200 g and 10 kg, although weights of 200 g are more common. Babies weigh 100–150 g. Barbel roe is poisonous and causes vomiting and diarrhea in some people. However, the fish itself can be eaten and recipes are available in The Illustrated London Cookery Book by Frederick Bishop. The name barbel derived from the Latin ''barba'', meaning beard, a reference to the two pairs of barbels, a longer pair pointing forwards and slightly down positioned, on the side of the mouth. Fish described as barbels by English-speaking people may not be known as barbels in their native country, although the root of the word may be similar. For instance, the Mediterranean barbel (''Barbus meridionalis' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Common Dace
The common dace (''Leuciscus leuciscus'') is a species of freshwater and brackish water ray-finned fish from the family Cyprinidae which is native to Europe but which has been introduced to other parts of the world. It is a quarry species for coarse anglers. Description The common dace differs from other members in the genus '' Leuciscus'' found in Europe by its inferior mouth, slightly longer upper jaw which has the tip of the upper lip level with the centre line of the eye and the lack of an obvious snout. It has a yellowish iris and a body which is covered in large silvery scales, the lateral line having 49–52 scales. The anal fin has a concave margin and the caudal fin is forked. The dorsal fin has 2–3 spines and 7–9 soft rays while the anal fin has 3 spines and 8–9 soft rays. The maximum size attained is a total length of . Distribution The common dace is native to Europe and northern Asia where its occurs in the basins of the North Sea, Baltic Sea, White Sea and B ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
