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Twaite Shad
The twait shad or twaite shad (''Alosa fallax'') is a species of fish in the family Alosidae. 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. This f ... [...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 has West Germanic origin and 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 cognate was ''Beornheard'', which was replaced or merged with 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). In Ireland, the name was an anglicized form of Brian. Geographical distribution Bernard is the second most common surname in France. 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), ... [...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 organism’s 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 fish 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 anterodo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Marine Fish Of North Africa
Marine is an adjective meaning of or pertaining to the sea or ocean. Marine or marines may refer to: Ocean * Maritime (other) * Marine art * Marine biology * Marine current power * Marine debris * Marine energy * 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 Canadian Navy ** Navy of the Democratic Republic of the Congo () ** Royal Danish Navy () ** Finnish Navy (, ) ** French Navy () ** Gabonese Navy () ** German Navy () ** Royal Moroccan Navy () ** Royal Netherlands Navy ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fish Of The Mediterranean Sea
A fish (: fish or fishes) is an aquatic, anamniotic, gill-bearing vertebrate animal with swimming fins and a hard skull, but lacking limbs with digits. Fish can be grouped into the more basal jawless fish and the more common jawed fish, the latter including all living cartilaginous and bony fish, as well as the extinct placoderms and acanthodians. In a break to the long tradition of grouping all fish into a single class (Pisces), modern phylogenetics views fish as a paraphyletic group. Most fish are cold-blooded, their body temperature varying with the surrounding water, though some large active swimmers like white shark and tuna can hold a higher core temperature. Many fish can communicate acoustically with each other, such as during courtship displays. The study of fish is known as ichthyology. The earliest fish appeared during the Cambrian as small filter feeders; they continued to evolve through the Paleozoic, diversifying into many forms. The earliest fi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fish Of The Black Sea
A fish (: fish or fishes) is an aquatic animal, aquatic, Anamniotes, anamniotic, gill-bearing vertebrate animal with swimming fish fin, fins and craniate, a hard skull, but lacking limb (anatomy), limbs with digit (anatomy), digits. Fish can be grouped into the more basal (phylogenetics), basal jawless fish and the more common jawed fish, the latter including all extant taxon, living cartilaginous fish, cartilaginous and bony fish, as well as the extinct placoderms and acanthodians. In a break to the long tradition of grouping all fish into a single Class (biology), class (Pisces), modern phylogenetics views fish as a paraphyletic group. Most fish are ectotherm, cold-blooded, their body temperature varying with the surrounding water, though some large nekton, active swimmers like white shark and tuna can hold a higher core temperature. Many fish can communication in aquatic animals#Acoustic, communicate acoustically with each other, such as during courtship displays. The stud ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fish Described In 1800
A fish (: fish or fishes) is an aquatic, anamniotic, gill-bearing vertebrate animal with swimming fins and a hard skull, but lacking limbs with digits. Fish can be grouped into the more basal jawless fish and the more common jawed fish, the latter including all living cartilaginous and bony fish, as well as the extinct placoderms and acanthodians. In a break to the long tradition of grouping all fish into a single class (Pisces), modern phylogenetics views fish as a paraphyletic group. Most fish are cold-blooded, their body temperature varying with the surrounding water, though some large active swimmers like white shark and tuna can hold a higher core temperature. Many fish can communicate acoustically with each other, such as during courtship displays. The study of fish is known as ichthyology. The earliest fish appeared during the Cambrian as small filter feeders; they continued to evolve through the Paleozoic, diversifying into many forms. The ea ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Alosa
''Alosa'' is a genus of fish, the river herrings, in the family Alosidae. 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 g ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
River Severn
The River Severn (, ), at long, is the longest river in Great Britain. It is also the river with the most voluminous flow of water by far in all of England and Wales, with an average flow rate of at Apperley, Gloucestershire. It rises in the Cambrian Mountains in mid Wales, at an altitude of , on the Plynlimon massif, which lies close to the Ceredigion/Powys border near Llanidloes. The river then flows through Shropshire, Worcestershire and Gloucestershire. The county towns of Shrewsbury, Worcester, England, Worcester and Gloucester lie on its course. The Severn's major tributaries are the River Vyrnwy, Vyrnwy, the River Tern, Tern, the River Teme, Teme, the Warwickshire Avon, and the River Stour, Worcestershire, Worcestershire Stour. By convention, the River Severn is usually considered to end, and the Severn Estuary to begin, after the Prince of Wales Bridge, between Severn Beach in South Gloucestershire and Sudbrook, Monmouthshire. The total area of the estuary's draina ... [...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 1714 construction of an old channel bypassing a dam, "originally cut for the passage of fish up and down the river", is mentio ... [...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 enhanced. 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. Its powers include defining ancient woodlands, awarding grants, designatin ... [...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 (biophysical), environment in England (and until 2013 also Wales). Based in Bristol, the Environment Agency is responsible for flood management, waste 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 statement, vision of the agency is of "a rich, healthy and diverse environment for present and future generations". Scope The Environment Agency's remit c ... [...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 England and Wales. 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 2008 financial crisis 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 of the House ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
