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Ruffe
The Eurasian ruffe (''Gymnocephalus cernua''), also known as ruffe or pope, is a freshwater fish found in temperate regions of Europe and northern Asia. It has been introduced into the Great Lakes of North America, reportedly with unfortunate results, as it is invasive and is reproducing faster than other species. Its common names are ambiguous – "ruffe" may refer to any local member of its genus ''Gymnocephalus'', which as a whole is native to Eurasia. Description The ruffe's colors and markings are similar to those of the walleye, an olive-brown to golden-brown color on its back, paler on the sides with yellowish white undersides. The ruffe can reach up to in length, but is usually around half that size. It is a very aggressive fish for its size. The ruffe also has a large, spiny dorsal fin which is likely distasteful to its predators. It also has two fins on top, the front fin has hard and sharp spines, the back fin has soft spines called rays. The most obvious featur ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gymnocephalus
''Gymnocephalus'' is a genus of ray-finned fishes from the family Percidae, which includes the perches, pike-perches and darters. They are from the Western Palearctic area, although one species, ''Gymnocephalus cernua'' has been accidentally introduced to the Great Lakes region where it is regarded as an invasive species. They have the common name "ruffe" and resemble the true perches in the genus ''Perca'', but are usually smaller and have a different pattern. Characteristics The species within the genus ''Gymnocephalus'' have a number of characters in common including that their dorsal fins are not completely separate, they have enlarged canals extending from the lateral line on their heads, the preorbital bone covers the maxillary bone, presence of setiform or bristle-like teeth, having very few or no vomerine and palatine teeth and the possession of three paired bones in the neck, known as extrascapulars, in their lateral line system, of which, two are simple tubes. Species T ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lake Superior
Lake Superior in central North America is the largest freshwater lake in the world by surface areaThe Caspian Sea is the largest lake, but is saline, not freshwater. and the third-largest by volume, holding 10% of the world's surface fresh water. The northern and westernmost of the Great Lakes of North America, it straddles the Canada–United States border with the province of Ontario to the north and east, and the states of Minnesota to the northwest and Wisconsin and Michigan to the south. It drains into Lake Huron via St. Marys River, then through the lower Great Lakes to the St. Lawrence River and the Atlantic Ocean. Name The Ojibwe name for the lake is ''gichi-gami'' (in syllabics: , pronounced ''gitchi-gami'' or ''kitchi-gami'' in different dialects), meaning "great sea". Henry Wadsworth Longfellow wrote this name as "Gitche Gumee" in the poem ''The Song of Hiawatha'', as did Gordon Lightfoot in his song " The Wreck of the ''Edmund Fitzgerald''". According to oth ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aral Sea
The Aral Sea ( ; kk, Арал теңізі, Aral teñızı; uz, Орол денгизи, Orol dengizi; kaa, Арал теңизи, Aral teńizi; russian: Аральское море, Aral'skoye more) was an endorheic basin, endorheic lake lying between Kazakhstan (Aktobe Region, Aktobe and Kyzylorda Regions) in the north and Uzbekistan (Karakalpakstan autonomous region) in the south which began shrinking in the 1960s and had largely dried up by the 2010s. The name roughly translates as "Sea of Islands", referring to over 1,100 islands that had dotted its waters. In the Mongolic languages, Mongolic and Turkic languages, ''aral'' means "island, archipelago". The Aral Sea drainage basin encompasses Uzbekistan and parts of Tajikistan, Turkmenistan, Kyrgyzstan, Kazakhstan, Afghanistan, and Iran. Formerly the fourth largest lake in the world with an area of , the Aral Sea began shrinking in the 1960s after the rivers that fed it were diverted by Soviet Union, Soviet irrigation proje ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Black Sea
The Black Sea is a marginal mediterranean sea of the Atlantic Ocean lying between Europe and Asia, east of the Balkans, south of the East European Plain, west of the Caucasus, and north of Anatolia. It is bounded by Bulgaria, Georgia, Romania, Russia, Turkey, and Ukraine. The Black Sea is supplied by major rivers, principally the Danube, Dnieper, and Don. Consequently, while six countries have a coastline on the sea, its drainage basin includes parts of 24 countries in Europe. The Black Sea covers (not including the Sea of Azov), has a maximum depth of , and a volume of . Most of its coasts ascend rapidly. These rises are the Pontic Mountains to the south, bar the southwest-facing peninsulas, the Caucasus Mountains to the east, and the Crimean Mountains to the mid-north. In the west, the coast is generally small floodplains below foothills such as the Strandzha; Cape Emine, a dwindling of the east end of the Balkan Mountains; and the Dobruja Plateau considerably farth ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Embryos
An embryo is an initial stage of development of a multicellular organism. In organisms that reproduce sexually, embryonic development is the part of the life cycle that begins just after fertilization of the female egg cell by the male sperm cell. The resulting fusion of these two cells produces a single-celled zygote that undergoes many cell divisions that produce cells known as blastomeres. The blastomeres are arranged as a solid ball that when reaching a certain size, called a morula, takes in fluid to create a cavity called a blastocoel. The structure is then termed a blastula, or a blastocyst in mammals. The mammalian blastocyst hatches before implantating into the endometrial lining of the womb. Once implanted the embryo will continue its development through the next stages of gastrulation, neurulation, and organogenesis. Gastrulation is the formation of the three germ layers that will form all of the different parts of the body. Neurulation forms the nervous s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Diameter
In geometry, a diameter of a circle is any straight line segment that passes through the center of the circle and whose endpoints lie on the circle. It can also be defined as the longest chord of the circle. Both definitions are also valid for the diameter of a sphere. In more modern usage, the length d of a diameter is also called the diameter. In this sense one speaks of diameter rather than diameter (which refers to the line segment itself), because all diameters of a circle or sphere have the same length, this being twice the radius r. :d = 2r \qquad\text\qquad r = \frac. For a convex shape in the plane, the diameter is defined to be the largest distance that can be formed between two opposite parallel lines tangent to its boundary, and the is often defined to be the smallest such distance. Both quantities can be calculated efficiently using rotating calipers. For a curve of constant width such as the Reuleaux triangle, the width and diameter are the same because all ... [...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] |
Benthic Zone
The benthic zone is the ecological region at the lowest level of a body of water such as an ocean, lake, or stream, including the sediment surface and some sub-surface layers. The name comes from ancient Greek, βένθος (bénthos), meaning "the depths." Organisms living in this zone are called benthos and include microorganisms (e.g., bacteria and fungi) as well as larger invertebrates, such as crustaceans and polychaetes. Organisms here generally live in close relationship with the substrate and many are permanently attached to the bottom. The benthic boundary layer, which includes the bottom layer of water and the uppermost layer of sediment directly influenced by the overlying water, is an integral part of the benthic zone, as it greatly influences the biological activity that takes place there. Examples of contact soil layers include sand bottoms, rocky outcrops, coral, and bay mud. Description Oceans The benthic region of the ocean begins at the shore line (intertida ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Journal Of Fish Biology
The ''Journal of Fish Biology'' covers all aspects of fish and fisheries biological research, both freshwater and marine. It is published by Wiley-Blackwell and is the official journal of the Fisheries Society of the British Isles The Fisheries Society of the British Isles is an international, non-political, learned society, based in the United Kingdom, that supports scientific activity in fish biology and management through charitable sponsorship. Membership is open to anyo .... External links * Homepage of The Fisheries Society of the British Isles Ichthyology journals Publications established in 1969 Monthly journals English-language journals Wiley-Blackwell academic journals {{zoo-journal-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chironomid
The Chironomidae (informally known as chironomids, nonbiting midges, or lake flies) comprise a family of nematoceran flies with a global distribution. They are closely related to the Ceratopogonidae, Simuliidae, and Thaumaleidae. Many species superficially resemble mosquitoes, but they lack the wing scales and elongated mouthparts of the Culicidae. The name Chironomidae stems from the Ancient Greek word ''kheironómos'', "a pantomimist". Common names and biodiversity This is a large taxon of insects; some estimates of the species numbers suggest well over 10,000 world-wide. Males are easily recognized by their plumose antennae. Adults are known by a variety of vague and inconsistent common names, largely by confusion with other insects. For example, chironomids are known as "lake flies" in parts of Canada and Lake Winnebago, Wisconsin, but "bay flies" in the areas near the bay of Green Bay, Wisconsin. They are called "sand flies", "muckleheads", "muffleheads", "Canadian so ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Great Lakes
The Great Lakes, also called the Great Lakes of North America, are a series of large interconnected freshwater lakes in the mid-east region of North America that connect to the Atlantic Ocean via the Saint Lawrence River. There are five lakes, which are Lake Superior, Superior, Lake Michigan, Michigan, Lake Huron, Huron, Lake Erie, Erie, and Lake Ontario, Ontario and are in general on or near the Canada–United States border. Hydrologically, lakes Lake Michigan–Huron, Michigan and Huron are a single body joined at the Straits of Mackinac. The Great Lakes Waterway enables modern travel and shipping by water among the lakes. The Great Lakes are the largest group of freshwater lakes on Earth by total area and are second-largest by total volume, containing 21% of the world's surface fresh water by volume. The total surface is , and the total volume (measured at the low water datum) is , slightly less than the volume of Lake Baikal (, 22–23% of the world's surface fresh water ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Kolyma
Kolyma (russian: Колыма́, ) is a region located in the Russian Far East. It is bounded to the north by the East Siberian Sea and the Arctic Ocean, and by the Sea of Okhotsk to the south. The region gets its name from the Kolyma River and mountain system, parts of which were not accurately mapped by Russian surveyors until 1926. Today the region consists roughly of the Chukotka Autonomous Okrug and the Magadan Oblast. The area, part of which is within the Arctic Circle, has a subarctic climate with very cold winters lasting up to six months of the year. Permafrost and tundra cover a large part of the region. Average winter temperatures range from (even lower in the interior), and average summer temperatures, from . There are rich reserves of gold, silver, tin, tungsten, mercury, copper, antimony, coal, oil, and peat. Twenty-nine zones of possible oil and gas accumulation have been identified in the Sea of Okhotsk shelf. Total reserves are estimated at 3.5 billion tons ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
