|
Hydrocynus Brevis
''Hydrocynus brevis'', also known as the tigerfish, Nile tigerfish or Sahelian tigerfish, is a predatory freshwater fish distributed throughout Africa. Appearance The tigerfish is silver in colour when young, with thin black horizontal stripes and an elongated body that tapers at both ends. As the fish grows, it will develop a bronze coloration and the stripes will fade. The ventral and caudal fins have a slight red-orange tint, and the adipose fin is grey to black. It grows to a length of SL."Hydrocynus Brevis (Gunther, 1864)." FishBase. N.p., n.d. Web. 22 Dec. 2013. Distribution This species has a wide distribution. It is found from Senegal to Ethiopia, throughout the Nile. In Northeast Africa it is found in the Ghazal and Jebel systems, Sudan, as well as Baro River, Ethiopia. In Western Africa it is known from Chad, Niger/Bénoué, Volta, Senegal and Gambia. Habitat and ecology A demersal, potamodromous freshwater species, ''Hydrocynus brevis'' prefers open-water habita ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Albert Günther
Albert Karl Ludwig Gotthilf Günther FRS, also Albert Charles Lewis Gotthilf Günther (3 October 1830 – 1 February 1914), was a German-born British zoologist, ichthyologist, and herpetologist. Günther is ranked the second-most productive reptile taxonomist (after George Albert Boulenger) with more than 340 reptile species described. Early life and career Günther was born in Esslingen in Swabia (Württemberg). His father was a ''Stiftungs-Commissar'' in Esslingen and his mother was Eleonora Nagel. He initially schooled at the Stuttgart Gymnasium. His family wished him to train for the ministry of the Lutheran Church for which he moved to the University of Tübingen. A brother shifted from theology to medicine, and he, too, turned to science and medicine at Tübingen in 1852. His first work was "''Ueber den Puppenzustand eines Distoma''". He graduated in medicine with an M.D. from Tübingen in 1858, the same year in which he published a handbook of zoology for students of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Senegal River
,french: Fleuve Sénégal) , name_etymology = , image = Senegal River Saint Louis.jpg , image_size = , image_caption = Fishermen on the bank of the Senegal River estuary at the outskirts of Saint-Louis, Senegal , map = Senegalrivermap.png , map_size = , map_caption = Map of the Senegal River drainage basin. , pushpin_map = , pushpin_map_size = , pushpin_map_caption= , subdivision_type1 = Country , subdivision_name1 = Senegal, Mauritania, Mali , subdivision_type2 = , subdivision_name2 = , subdivision_type3 = , subdivision_name3 = , subdivision_type4 = , subdivision_name4 = , subdivision_type5 = , subdivision_name5 = , length = , width_min = , width_avg = , width_max = , depth_min = , depth_avg = , depth_max = , discharge1_location= , discharge1_min = , discharge1_avg = , di ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fish Of Africa
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. Most f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Alestidae
African tetras (family Alestidae, formerly spelled Alestiidae) are a group of characiform fish exclusively found in Africa. This family contains about 18 genera and 119 species. Among the best known members are the Congo tetra, and African tigerfish. Taxonomy Taxonomy based on Van der Laan 2017 and Nelson, Grande & Wilson 2016. * Family Alestiidae Cockerell 1910 ** Genus †'' Alestoides'' Monod & Gaudant 1998 ** Genus †'' Arabocharax'' Micklich & Roscher 1990 ** Genus †'' Bunocharax'' Van Neer 1994 ** Genus †'' Eurocharax'' Gaudant 1980 ** Genus †'' Mahengecharax'' Murray 2003 ** Genus †'' Sindacharax'' Greenwood & Howes 1975 ** Genus ''Brycinus'' Valenciennes 1850 'Brycinus macrolepidotus'' species-group** Subfamily Bryconaethiopinae Hoedeman 1951 *** Genus '' Bryconaethiops'' Günther 1873 *** Genus '' Brachyalestes'' Günther 1864 'Brycinus nurse'' species-group** Subfamily Petersiinae Poll 1967 *** Genus '' Alestopetersius'' Hoedeman 1951 Duboisialestes.html"_ ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hydrocynus Brevis Head Detail
''Hydrocynus'' is a genus of large characin fish in the family Alestidae commonly called "tigerfish," native to the African continent. The genus name is derived from Ancient Greek ὕδωρ ("water"Liddell, H.G. & Scott, R. (1940). ''A Greek-English Lexicon. revised and augmented throughout by Sir Henry Stuart Jones. with the assistance of. Roderick McKenzie.'' Oxford: Clarendon Press.) + κύων ("dog"). (In fact, this fish is popularly referred to as ''poisson chien'' (dog fish) in French-speaking West Africa.) The genus contains five species, all popularly known as "African tigerfish" for their fierce predatory behaviour and other characteristics that make them excellent game fish. ''Hydrocynus'' are normally piscivorous, but ''H. vittatus'' is the only freshwater fish proven to prey on birds in flight. [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pollution
Pollution is the introduction of contaminants into the natural environment that cause adverse change. Pollution can take the form of any substance (solid, liquid, or gas) or energy (such as radioactivity, heat, sound, or light). Pollutants, the components of pollution, can be either foreign substances/energies or naturally occurring contaminants. Although environmental pollution can be caused by natural events, the word pollution generally implies that the contaminants have an anthropogenic source – that is, a source created by human activities. Pollution is often classed as point source or nonpoint source pollution. In 2015, pollution killed nine million people worldwide (one in six deaths). This remained unchanged in 2019, with little real progress against pollution being identifiable. Air pollution accounted for of these earlier deaths. Major forms of pollution include air pollution, light pollution, litter, noise pollution, plastic pollution, soil contamination, radioactiv ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Deforestation
Deforestation or forest clearance is the removal of a forest or stand of trees from land that is then converted to non-forest use. Deforestation can involve conversion of forest land to farms, ranches, or urban use. The most concentrated deforestation occurs in tropical rainforests. About 31% of Earth's land surface is covered by forests at present. This is one-third less than the forest cover before the expansion of agriculture, a half of that loss occurring in the last century. Between 15 million to 18 million hectares of forest, an area the size of Bangladesh, are destroyed every year. On average 2,400 trees are cut down each minute. The Food and Agriculture Organization of the United Nations defines deforestation as the conversion of forest to other land uses (regardless of whether it is human-induced). "Deforestation" and "forest area net change" are not the same: the latter is the sum of all forest losses (deforestation) and all forest gains (forest expansion) in a gi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ghana
Ghana (; tw, Gaana, ee, Gana), officially the Republic of Ghana, is a country in West Africa. It abuts the Gulf of Guinea and the Atlantic Ocean to the south, sharing borders with Ivory Coast in the west, Burkina Faso in the north, and Togo in the east.Jackson, John G. (2001) ''Introduction to African Civilizations'', Citadel Press, p. 201, . Ghana covers an area of , spanning diverse biomes that range from coastal savannas to tropical rainforests. With nearly 31 million inhabitants (according to 2021 census), Ghana is the List of African countries by population, second-most populous country in West Africa, after Nigeria. The capital and List of cities in Ghana, largest city is Accra; other major cities are Kumasi, Tamale, Ghana, Tamale, and Sekondi-Takoradi. The first permanent state in present-day Ghana was the Bono state of the 11th century. Numerous kingdoms and empires emerged over the centuries, of which the most powerful were the Kingdom of Dagbon in the north and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Potamodromous
Fish migration is animal migration, mass relocation by fish from one area or body of water to another. Many types of fish migrate on a regular basis, on time scales ranging from daily to annually or longer, and over distances ranging from a few metres to thousands of kilometres. Such migrations are usually done for better feeding or to reproduce, but in other cases the reasons are unclear. Fish migrations involve movements of school of fish, schools of fish on a scale and duration larger than those arising during normal daily activities. Some particular types of migration are ''anadromous'', in which adult fish live in the sea and migrate into fresh water to spawn (biology), spawn; and ''catadromous'', in which adult fish live in fresh water and migrate into salt water to spawn. Marine forage fish often make large migrations between their spawning, feeding and nursery grounds. Movements are associated with ocean currents and with the availability of food in different areas at di ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Demersal
The demersal zone is the part of the sea or ocean (or deep lake) consisting of the part of the water column near to (and significantly affected by) the seabed and the benthos. The demersal zone is just above the benthic zone and forms a layer of the larger profundal zone. Being just above the ocean floor, the demersal zone is variable in depth and can be part of the photic zone where light can penetrate, and photosynthetic organisms grow, or the aphotic zone, which begins between depths of roughly and extends to the ocean depths, where no light penetrates. Fish The distinction between demersal species of fish and pelagic species is not always clear cut. The Atlantic cod (''Gadus morhua'') is a typical demersal fish, but can also be found in the open water column, and the Atlantic herring (''Clupea harengus'') is predominantly a pelagic species but forms large aggregations near the seabed when it spawns on banks of gravel. Two types of fish inhabit the demersal zone: those ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gambia River
The Gambia River (formerly known as the River Gambra) is a major river in West Africa, running from the Fouta Djallon plateau in north Guinea westward through Senegal and The Gambia to the Atlantic Ocean at the city of Banjul. It is navigable for about half that length. The river is strongly associated with The Gambia, the smallest country in mainland Africa, which occupies the downstream half of the river and its two banks. Geography The Gambia River runs a total length of . From the Fouta Djallon, it runs northwest into the Tambacounda Region of Senegal, where it flows through the Parc National du Niokolo Koba, then is joined by the Nieri Ko and and passing through the Barrakunda Falls before entering the Gambia at Koina. At this point, the river runs generally west, but in a meandering course with a number of oxbows, and about from its mouth it gradually widens, to over wide where it meets the sea. Crossings There are several bridges crossing the river. The largest an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Volta River
The Volta River is the main river system in the West African country of Ghana. It flows south into Ghana from the Bobo-Dioulasso highlands of Burkina Faso. The main parts of the river are the Black Volta, the White Volta, and the Red Volta. In the northwest, the Black Volta forms the international borders between the Ivory Coast, Ghana, and Burkina Faso. The Volta flows southward along the Akwapim-Togoland highlands, and it empties into the Atlantic Ocean at the Gulf of Guinea at Ada Foah. It has a smaller tributary river, the Oti, which enters Ghana from Togo in the east. The Volta River has been dammed at Akosombo for the purpose of generating hydroelectricity. The reservoir named Lake Volta stretches from Akosombo Dam in the south to the northern part of the country, and is the largest man-made reservoir by area in the world. Volta was named by the Portuguese, meaning twist or turn. The country of Burkina Faso was formerly called Upper Volta, after the river. The reserv ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
