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Twait Shad
The twait shad or twaite shad (''Alosa fallax'') is a species of fish in the family Clupeidae. It is found in the eastern Atlantic Ocean and the Mediterranean Sea and is an anadromous fish which lives in the sea but migrates into fresh water to spawn. In appearance it resembles an Atlantic herring but has a row of six to ten distinctive spots on its silvery flanks. They become mature when three or more years old and migrate to estuaries, later swimming up rivers to spawn. Populations of this fish have declined due to overfishing, pollution and habitat destruction. Conservation of this species is covered by Appendix III of the Bern Convention and Appendix II and V of the European Community Habitats Directive. Description The twait shad is a typical herring-type fish and much resembles the allis shad. It has no lateral line and the belly is more rounded than that of the sprat and Baltic herring. The gill cover is ridged and the caudal peduncle has large, plate-like scales. T ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bernard Germain Étienne De La Ville, Comte De Lacépède
Bernard ('' Bernhard'') is a French and West Germanic masculine given name. It is also a surname. The name is attested from at least the 9th century. West Germanic ''Bernhard'' is composed from the two elements ''bern'' "bear" and ''hard'' "brave, hardy". Its native Old English reflex was ''Beornheard'', which was replaced by the French form ''Bernard'' that was brought to England after the Norman Conquest. The name ''Bernhard'' was notably popular among Old Frisian speakers. Its wider use was popularized due to Saint Bernhard of Clairvaux (canonized in 1174). Bernard is the second most common surname in France. Geographical distribution As of 2014, 42.2% of all known bearers of the surname ''Bernard'' were residents of France (frequency 1:392), 12.5% of the United States (1:7,203), 7.0% of Haiti (1:382), 6.6% of Tanzania (1:1,961), 4.8% of Canada (1:1,896), 3.6% of Nigeria (1:12,221), 2.7% of Burundi (1:894), 1.9% of Belgium (1:1,500), 1.6% of Rwanda (1:1,745), 1.2% of Germany ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Operculum (fish)
The operculum is a series of bones found in bony fish and chimaeras that serves as a facial support structure and a protective covering for the gills; it is also used for respiration and feeding. Anatomy The opercular series contains four bone segments known as the preoperculum, suboperculum, interoperculum and operculum. The preoperculum is a crescent-shaped structure that has a series of ridges directed posterodorsally to the organisms canal pores. The preoperculum can be located through an exposed condyle that is present immediately under its ventral margin; it also borders the operculum, suboperculum, and interoperculum posteriorly. The suboperculum is rectangular in shape in most bony fishy and is located ventral to the preoperculum and operculum components. It is the thinnest bone segment out of the opercular series and is located directly above the gills. The interoperculum is triangular shaped and borders the suboperculum posterodorsally and the preoperculum anterodorsa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Marine Fauna Of North Africa
Marine is an adjective meaning of or pertaining to the sea The sea, connected as the world ocean or simply the ocean, is the body of salty water that covers approximately 71% of the Earth's surface. The word sea is also used to denote second-order sections of the sea, such as the Mediterranean Sea, ... or ocean. Marine or marines may refer to: Ocean * Maritime (other) * Marine art * Marine biology * Marine debris * Marine habitats * Marine life * Marine pollution Military * Marines, a naval-based infantry force ** United States Marine Corps ** Royal Marines of the UK ** Brazilian Marine Corps ** Spanish Marine Infantry ** Fusiliers marins (France) ** Indonesian Marine Corps ** Republic of China Marine Corps ** Republic of Korea Marine Corps ** Royal Thai Marine Corps *"Marine" also means "navy" in several languages: ** Austro-Hungarian Navy () ** Belgian Navy (, , ) ** Royal Canadian Navy () *** Provincial Marine (1796–1910), a predecessor to the Royal Canadi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fish Of The Mediterranean Sea
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] |
Fish Of The Black Sea
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] |
Fish Described In 1800
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 fis ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Alosa
''Alosa'' is a genus of fish, the river herrings, in the family Clupeidae. Along with other genera in the subfamily Alosinae, they are generally known as shads. tp://ftp.fao.org/docrep/fao/009/ac482e/ac482e27.pdf Subfamily AlosinaeFAO Fisheries Bulletin They are distinct from other herrings by having a deeper body and spawning in rivers. Several species can be found on both sides of the Atlantic Ocean and the Mediterranean Sea. Also, several taxa occur in the brackish-water Caspian Sea and the Black Sea basin. Many are found in fresh water during spawning and some are only found in landlocked fresh water. Fossil record These fishes lived from the Eocene to Quaternary (from 55 million years ago to now). Fossils have been found in Canada, the United States, Greece, Kazakhstan, Azerbaijan, Hungary, Romania, and Italy. Appearance ''Alosa'' species are generally dark on the back and top of the head, with blue, violet, or greenish tints. Some can be identified as having a grey or ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
River Severn
, name_etymology = , image = SevernFromCastleCB.JPG , image_size = 288 , image_caption = The river seen from Shrewsbury Castle , map = RiverSevernMap.jpg , map_size = 288 , map_caption = Tributaries (light blue) and major settlements on and near the Severn (bold blue) , pushpin_map = , pushpin_map_size = 288 , pushpin_map_caption= , subdivision_type1 = Country , subdivision_name1 = England and Wales , subdivision_type2 = , subdivision_name2 = , subdivision_type3 = Region , subdivision_name3 = Mid Wales, West Midlands, South West , subdivision_type4 = Counties , subdivision_name4 = Powys, Shropshire, Worcestershire, Gloucestershire , subdivision_type5 = Cities , subdivision_name5 = Shrewsbury, Worcester, Gloucester, Bristol , length = , width_min = , width_avg = , width_max = , depth_min = , depth_avg ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fish Ladder
A fish ladder, also known as a fishway, fish pass, fish steps, or fish cannon is a structure on or around artificial and natural barriers (such as dams, locks and waterfalls) to facilitate diadromous fishes' natural migration as well as movements of potamodromous species. Most fishways enable fish to pass around the barriers by swimming and leaping up a series of relatively low steps (hence the term ''ladder'') into the waters on the other side. The velocity of water falling over the steps has to be great enough to attract the fish to the ladder, but it cannot be so great that it washes fish back downstream or exhausts them to the point of inability to continue their journey upriver. History Written reports of rough fishways date to 17th-century France, where bundles of branches were used to make steps in steep channels to bypass obstructions. A pool and weir salmon ladder was built around 1830 by James Smith, a Scottish engineer on the River Teith, near Deanston, Perths ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Natural England
Natural England is a non-departmental public body in the United Kingdom sponsored by the Department for Environment, Food and Rural Affairs. It is responsible for ensuring that England's natural environment, including its land, flora and fauna, freshwater and marine environments, geology and soils, are protected and improved. It also has a responsibility to help people enjoy, understand and access the natural environment. Natural England focuses its activities and resources on four strategic outcomes: * a healthy natural environment * enjoyment of the natural environment * sustainable use of the natural environment * a secure environmental future Roles and responsibilities As a non-departmental public body (NDPB), Natural England is independent of government. However, the Secretary of State for Environment, Food & Rural Affairs has the legal power to issue guidance to Natural England on various matters, a constraint that was not placed on its predecessor NDPBs. Its powers in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Environment Agency
The Environment Agency (EA) is a non-departmental public body, established in 1996 and sponsored by the United Kingdom government's Department for Environment, Food and Rural Affairs, with responsibilities relating to the protection and enhancement of the environment in England (and until 2013 also Wales). Based in Bristol, the Environment Agency is responsible for flood management, regulating land and water pollution, and conservation. Roles and responsibilities Purpose The Environment Agency's stated purpose is, "to protect or enhance the environment, taken as a whole" so as to promote "the objective of achieving sustainable development" (taken from the Environment Act 1995, section 4). Protection of the environment relates to threats such as flood and pollution. The vision of the agency is of "a rich, healthy and diverse environment for present and future generations". Scope The Environment Agency's remit covers almost the whole of England, about 13 million&nbs ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Canal & River Trust
The Canal & River Trust (CRT), branded as in Wales, holds the guardianship of 2,000 miles of canals and rivers, together with reservoirs and a wide range of heritage buildings and structures, in England and Wales. Launched on 12 July 2012, the Trust took over the responsibilities of the state-owned British Waterways in those two places. History The concept of a National Waterways Conservancy was first championed and articulated in the 1960s by Robert Aickman, the co-founder of the Inland Waterways Association, as a way to secure the future of Britain's threatened inland waterways network. The idea was revived by the management of British Waterways in 2008 in response to increasing cuts in grant-in-aid funding, a drop in commercial income after the financial crisis of 2007–2008 and growing calls by waterway users for a greater say in the running of the waterways. On 18 May 2009, launching 'Twenty Twenty – a vision for the future of our canals and rivers' on the terrace ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
