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Newlyn

Newlyn

Newlyn (Cornish: Lulynn) is a town in southwest Cornwall, UK. The town forms a small conurbation with neighbouring Penzance, and part of the civil parish of Penzance. The principal industry in Newlyn is fishing, and the town relies upon its harbour. The UK National Tidal and Sea Level Facility (NTSLF) maintains a tidal observatory at Newlyn, and the UK Fundamental Benchmark is maintained there. The Ordnance Survey, Britain's mapping agency, used to base all contour lines and spot heights on the mean sea level at Newlyn defined by this benchmark. It was made famous in the 1880s and 1980s for its Newlyn School artists' colony, including the painters Thomas Cooper Gotch and Henry Scott Tuke. At the heart of Newlyn (http://www.newlyn.info) is the harbour (http://www.newlynharbour.co.uk) the largest (by turnover >£18 million 2004) fishing port in England. The fishing fleet boasts a number of different catching methods: beam trawling, trawling, gill netting, potting and a large number of under 10m vessels that fish inshore. The port was a major catcher of Pilchards untill the 1960s. Today, a handful of vessels have resumed pilchard fishing and use a modern version of the ring net. The largest vessels are beam trawlers owned by the Stevenson family. Most of the other vessels are owned by their skippers.

External links

- [http://www.newlyn.info/index.html newlyn.info - great source of information on Newlyn in Cornwall]
- [http://dmoz.org/Regional/Europe/United_Kingdom/England/Cornwall/Newlyn/ Newlyn (DMOZ.org)]
- [http://www.cornwalls.co.uk/photos/Newlyn-photos.htm Newlyn Photographs]
- [http://www.pol.ac.uk/ntslf/tgi/ntobs.html NTSLF page about the Newlyn Tidal Observatory and the Fundamental Benchmark] Category:Towns in Cornwall

UÇK

UÇK is an acronym used by two Albanian guerrilla movements from 1992 to 2001:
- The most well known group is Ushtria Çlirimtare e Kosovës (Albanian for the Kosovo Liberation Army - KLA), which operated in Kosovo from 1995 to 1999. (The name was in use from 1992, but the guerrilla did not start its armed uprising before 1995.)
- Not so well known is Ushtria Çlirimtare Kombëtare (Albanian for National Liberation Army), which operated in the Republic of Macedonia in 2000 and 2001. This movement is often confused with the KLA because of its identical (Albanian) acronym, and because many of the NLA soldiers were KLA veterans.

External links

- [http://www.kosovo.com/kla2.html KOSOVO LIBERATION ARMY - Freedom Fighters or...] Truth in facts and testimonies
- [http://www.axisglobe.com/article.asp?article=519 Ibrahim Rugova: Victory of the Passive Resistance?] Category:History of Kosovo

Conurbation

A conurbation is an urban area comprising a number of cities or towns which, through population growth and expansion, have physically merged to form one continuous built up area. It is thus a polycentric form of agglomeration. A metropolitan area usually combines one or several conurbations with peripheral zones not themselves necessarily urban in character, but closely dependent on the conurbation(s) in terms of employment and commerce.

Examples

- Auckland
- Bajalta California
- Berlin
- Brisbane
- Gran Buenos Aires
- Greater Helsinki
- Greater London
- Greater Manchester
- Greater Mexico City
- The Greater Toronto Area (GTA)
- Helsinki
- Hong Kong
- Medway
- Metro Manila
- Mumbai
- Osaka-Kobe-Kyoto
- Oslo
- Randstad
- Rhine-Ruhr
- San Francisco Bay Area
- Stockholm
- Tricity
- Upper Silesian Metropolitan Area
- West Midlands

External links

- [http://www.demographia.com/db-world-muni.htm Largest cities of the world (municipalities)] Category:Urban studies and planning

Civil parish

:Parishes in Louisiana USA are sometimes called 'civil parishes' see List of parishes of Louisiana In England a civil parish (usually just parish) is the lowest unit of local government, lower than districts or counties. Civil parishes in the modern sense were established in 1894, and although their origins are in the system of ecclesiastic parishes, they no longer have anything to do with the Church of England. Parishes previously also existed in Scotland and Wales. They still formally exist in Ireland, but are now largely obselete. Ireland]

Geography

Parishes do not cover the whole of England, and mostly exist in rural areas and smaller urban areas. Civil parishes were abolished in London in 1965 and in other large urban areas in 1974. Civil parishes vary greatly in size, many cover tiny hamlets with populations of less than 100, whereas some large ones cover towns with populations of tens of thousands. The largest civil parish is Weston-super-Mare, which has a population of 71,758. In many cases, several small villages are part of a joint parish. Large urban areas are mostly unparished, but there is generally nothing to stop their establishment. For example, Birmingham has a parish, New Frankley, whilst Oxford has four, and Northampton has seven. In Greater London, however, the current legislative framework for local government forbids the establishment of civil parishes. The policy of the present government is to encourage creation of town and parish councils in unparished areas. The Local Government and Rating Act 1997 created a proceedure which gave local residents the right to demand that a new parish and council be created in unparished areas [http://www.createacouncil.org.uk/] (except in Greater London). If at least 10% of electors in an area of a proposed new parish sign a petition demanding its creation, then the local district council or unitary authority must consider the proposal. The final decision rests with the Office of the Deputy Prime Minister. Recently established councils include those for Daventry (2003), and Folkestone (2004). 2003 saw the setting up of seven new parish councils for Burton-upon-Trent, and in 2001 the Milton Keynes urban area became entirely parished with ten new parishes. Parishes can also be abolished, on request, such as Birtley, which will be abolished in 2006.

Parish councils

Civil parishes are usually administered by parish councils, which have various local responsibilities. A parish council can also be called a Town Council or occasionally a 'City Council' (but not all city councils are parish councils). It can become a Town Council unilaterally, simply by making a resolution to do so. Around 400 parish councils are called town councils. A parish can only gain city status however if it is granted by the crown. In England, there are currently six parishes with city status : Chichester, Ely, Hereford, Lichfield, Ripon, and Wells. The Chair of a Town council or City council will usually have the title Mayor. If a parish has fewer than 200 electors it is usually deemed too small to have a parish council, and instead it has a parish meeting; an example of direct democracy. Alternatively several small parishes can be grouped together and share a common parish council. There are about 8,700 parish and town councils in England, and about 1,500 parish meetings. Since 1997 around 100 new civil parishes have been created, in some cases splitting existing civil parishes, while in others creating new ones from unparished areas.

Powers and functions

Typical activities undertaken by parish or town councils include:
- The provision and upkeep of certain local facilities such as allotments, bus shelters, parks, playgrounds, public seats, public toilets, public clocks, village or town halls, and various leisure facillities.
- Maintenence of footpaths and street lighting
- Since 1997 parish councils have had new powers to provide community transport, crime prevention measures (such as CCTV) and to contribute money towards traffic calming schemes.
- Parish councils are supposed to act as a channel of local opinion to larger local government bodies, and as such have the right to be consulted on any planning decisions affecting the parish.
- Giving of grants to local voluntary organisations, and sponsoring public events.
- Other responsibilities include litter collection, and entering Britain in Bloom. The role played by parish councils varies. Smaller parish councils have only limited resources and generally play only a minor role, while some larger parish councils have a role similar to that of a small district council. Parish councils receive funding by levying a 'precept' on the council tax paid by the residents of the parish.

Councillors and elections

Parish councils are run by volunteer councillors who are elected to serve for four years. Different councils have different numbers of councillors. Most parish councillors are elected to represent the entire parish. Only if there are more candidates standing for election than there are seats on the council will an election be held. Sometimes a city or town is abolished as a district, and it is considered desirable to maintain continuity of the charter until a parish council to replace it can be set up. In this case Charter Trustees perform some of the functions of a parish council, and maintain traditions such as mayoralty. An example of such a city was Hereford, whose city council was merged in 1998 to form a unitary Herefordshire. The area of the city of Hereford remained unparished until 2000 when a parish council was created for the city.

Deserted parishes

The 2001 census recorded several parishes with no inhabitants. These were Chester Castle (in the middle of Chester city centre), Newland with Woodhouse Moor, Beaumont Chase, Martinsthorpe, Meering, Stanground North (subsequently abolished), Sturston, Tottington, and Tyneham. The latter three had been taken over by the British Armed Forces during the Second World War and remain deserted.

Scotland, Wales and Ireland

In Wales the equivalent body to a Parish council is termed a Community council. The administrative counties of Scotland were sub-divided into parishes, but these lacked their own councils. Scotland has now bodies called Community councils, but these are not equivalent to and have fewer powers than the English parishes and Welsh communities. In Ireland, counties are divided into civil parishes. Irish civil parishes are divided into townlands. Counties are also divided into larger subdivisions called baronies, which are made up of a number of parishes or parts of parishes. Both civil parishes and baronies are now largely obsolete (except for some purposes such as legal transactions involving land) and are no longer used for local government purposes.

History

Parishes arose from common law and Church of England divisions. The Poor Law saw parishes being given responsibility for pauper relief, and allowed to charge a rate. The parishes were run by vestries, which could be either 'open' (where all parisioners could attend) or 'select' (oligarchial). The 19th century saw an increase in the responsibility of parishes, although the poor law powers were transferred to Poor Law Unions. The latter part of the century saw most of the ancient irregularities in the system cleaned up, with the majority of exclaves abolished, and extra parochial areas converted into parishes themselves. Also, borders were altered to avoid parishes being split between counties. In 1894, elected parish councils were set up in all parishes with enough electors - in all the newly-formed rural districts of England and Wales. Urban parishes only nominally existed, and were generally coterminous with the urban district or municipal borough in which they were situated. Large towns originally split between multiple parishes were consolidated into one parish. 1974 saw the Local Government Act 1972. Many former urban districts and municipal boroughs that were being abolished rather than succeeded were continued as new parishes. Urban areas that were considered too large to be single parishes were refused this permission and became unparished areas. The Act also led to the possibility sub-division of all districts (apart from London boroughs, reformed in 1965), into multiple civil parishes. For example, Oxford, whilst entirely unparished in 1974, now has 4 civil parishes.

External links

- [http://www.nalc.gov.uk/ The National Association of Local Councils] - represents English parish councils and Welsh community councils
- [http://www.nalc.gov.uk/information/legal/powers/index.html Full list of the powers of parish councils]
- [http://www.thanet.gov.uk/assets/pdfs/consultation/396TDCParishbook.pdf Consultation document explaining costs and benefits of a parish council for Ramsgate] Category:Parishes Category:Local government of the United Kingdom

Fishing

Fishing is the activity of hunting for fish. By extension, the term fishing is also applied to hunting for other aquatic animals such as various types of shellfish as well as squid, octopus, turtles, frogs and some edible marine invertebrates. The term fishing is usually not applied to the hunting of aquatic mammals such as whales. Fishing is an ancient and worldwide practice with many techniques and traditions, and it has been transformed by modern technological developments.

Fishing in antiquity

Origins

whales Fishing is a very ancient practice that dates back at least to the Mesolithic period which began about 10,000 years ago. We know from archaeological features such as shell middens [http://www.york.ac.uk/depts/arch/middens/index.htm], discarded fish bones and cave paintings that sea foods were important and consumed in significant quantities. During this time, most people lived a hunter-gather life style and were, of necessity, constantly on the move. However, where there are a few early examples of permanent settlements (though not necessarily permanently occupied) such as those at Lepenski Vir, they are almost always associated with fishing as a major source of food. The neolithic culture and technology spread worldwide between about 8,000 and 4,000 years ago. With the new technologies of farming and pottery came the basic forms of most fishing methods known today. Fishing may even pre-date the development of modern humans. There is a controversial theory called the aquatic ape hypothesis which proposes that the ancestors of modern humans went through one or more periods of time living in a semi-aquatic setting and that they gathered most of their food from shallow coastal or other waters before their descendants returned to a more land-based existence.

Ancient archaeology

Ancient representations

aquatic ape hypothesis The ancient river Nile was full of fish; fresh and dried fish were a staple food for much of the population. The Egyptians invented various implements and methods for fishing and these are clearly illustrated in tomb scenes, drawings, and papyrus documents. Simple reed boats served for fishing. Woven nets, weir baskets made from willow branches, harpoons and hook and line (the hooks having a length of between eight millimetres and eighteen centimetres) were all being used. By the 12th dynasty, metal hooks with barbs were being used. As is fairly common today, the fish were clubbed to death after capture. Nile perch, catfish and eels were among the most important fish. Some representations hint at fishing being pursued as a pastime. Fishing scenes are rarely represented in ancient Greek culture, a reflection of the low social status of fishing. There is a wine cup, dating from 510–500 BC, that shows a boy crouched on a rock with a fishing-rod in his right hand and a basket in his left. In the water below, a rounded object of the same material with an opening on the top. This has been identified as a fish-cage used for keeping live fish, or as a fish-trap. It is clearly not a net. This object is currently in the Museum of Fine Arts, Boston. [http://www.mfa.org/collections/search_art.asp?recview=true&id=153702&coll_keywords=fishing&coll_accession=&coll_name=&coll_artist=&coll_place=&coll_medium=&coll_culture=&coll_classification=&coll_credit=&coll_provenance=&coll_location=&coll_has_images=&coll_on_view=&coll_sort=0&coll_sort_order=0&coll_package=0&coll_start=71 Image:Ancient angler] ancient Greek Pictorial evidence of Roman fishing comes from mosaics which show fishing from boats with rod and line as well as nets. Various species such as conger, lobster, sea urchin, octopus and cuttlefish are illustrated. [http://museum.agropolis.fr/english/pages/expos/aliments/poissons/images/mosaique.htm Image of Roman mosaic]. In a parody of fishing, a type of gladiator called retiarius was armed with a trident and a casting-net. He would fight against the murmillo, who carried a short sword and a helmet with the image of a fish on the front. The Greco-Roman sea god Neptune is depicted as wielding a fishing trident.

Ancient literature

There are numerous references to fishing in ancient literature; in most cases, however, the descriptions of nets and fishing-gear do not go into detail, and the equipment is described in general terms. An early example from the Bible in Job 41:7: Canst thou fill his skin with barbed irons? or his head with fish spears? [http://bible.tmtm.com/wiki/Job_Chapter_41] The Greek historian Polybius ((ca 203 BC-120 BC), in his Histories, describes hunting for swordfish by using a harpoon with a barbed and detachable head. [http://www.perseus.tufts.edu/cgi-bin/ptext?lookup=Plb.+34.3] Oppian of Corycus, a Greek author wrote a major treatise on sea fishing, the Halieulica or Halieutika, composed between 177 and 180. This is the ealiest such work to have survived intact to the modern day. Oppian describes various means of fishing including the use of nets cast from boats, scoop nets held open by a hoop, spears and tridents, and various traps “which work while their masters sleep”. Oppian’s description of fishing with a “motionless” net is also very interesting: :The fishers set up very light nets of buoyant flax and wheel in a circle round about while they violently strike the surface of the sea with their oars and make a din with sweeping blow of poles. At the flashing of the swift oars and the noise the fish bound in terror and rush into the bosom of the net which stands at rest, thinking it to be a shelter: foolish fishes which, frightened by a noise, enter the gates of doom. Then the fishers on either side hasten with the ropes to draw the net ashore. From ancient representations and literature it is clear that fishing boats were typically small, lacking a mast or sail, and were only used close to the shore. In traditional Chinese history, history begins with three semi-mystical and legendary individuals who taught the Chinese the arts of civilization around 2800-2600 BC: of these Fu Hsi was reputed to be the inventor of writing, hunting, trapping, and fishing.

Fishing techniques

Hand fishing

It is possible to fish with minimal equipment by using only the hands. In the USA catching catfish in this way is known as noodling. In the British Isles, the practice of catching trout by hand is known as trout tickling; it is an art mentioned several times in the plays of Shakespeare. Trout binning is a method of fishing, possibly fictional, performed with a sledgehammer. [http://www.gutenberg.org/etext/11267] Divers can catch lobsters by hand. Pearl diving is the practice of hunting for oysters by free-diving to depths of up to 30 m. Hand-line fishing is a technique requiring a fishing line with a weight and one or more lure-like hooks.

Spear and bow fishing

Spear fishing is an ancient method of fishing and may be conducted with an ordinary spear or a specialised variant such as an eel spear ([http://www.clarelibrary.ie/eolas/claremuseum/riches_of_clare/water/eel_spear2.htm Image]) or the trident. A small trident type spear with a long handle is used in the American South and Midwest for "gigging" bullfrogs with a bright light at night, or for gigging carp and other trash fish in the shallows. Traditional spear fishing is restricted to shallow waters, but the development of the speargun has made the method much more efficient. With practice, divers are able to hold their breath for up to four minutes; of course, a diver with underwater breathing equipment can dive for much longer periods. Hunter gatherers may use the bow to kill fish in shallow water.

Fishing nets

bow All fishing nets are meshes usually formed by knotting a relatively thin thread. Modern nets are usually made of artificial polyamides like nylon, although nets of organic polyamides such as wool or silk thread were common until recently and are still used in certain areas. A small hand net held open by a hoop and possibly on the end of a long stiff handle has been known since antiquity and may be used for sweeping up fish near the water surface. Such a net used by an angler to aid in landing a captured fish is known as a landing net. In England, hand netting is the only legal way of catching eels and has been practiced for thousands of years on the River Parrett and River Severn. A casting net is circular with a weighted periphery. Sizes vary up to about 4 m diameter. The net is thrown by hand in such a manner that it speads out on the water and sinks. Fish are caught as the net is hauled back in. [http://www.nccoastalfishing.com/index.htm?casting.htm~main]. River Severn 1972]] Coracle-fishing is performed by two men, each seated in his coracle and with one hand holding the net while, with the other, he plies his paddle. When a fish is caught, each hauls up his end of the net until the two coracles are brought to touch and the fish is then secured. The Chinese fishing nets (Cheena vala) found at Kochi in India are an unusual method of fishing. Huge mechanical contrivances hold out horizontal nets of 20 m or more across. The nets are dipped into the water and raised again, but otherwise cannot be moved. A seine is a large fishing net that hangs vertically in the water by attaching weights along the bottom edge and floats along the top. Trawling is a method of fishing that involves actively pulling a fishing net through the water behind one or more boats. A gillnet catches fish which try to pass through it by snagging on the gill covers. Thus trapped, the fish can neither advance trough the net nor retreat. Ghost nets are nets that have been lost at sea. They may continue to be a menace to wildlife for many years.

Dredging

There are types of dredges used for collecting scallops or oysters from the seabed. They tend to have the form of a scoop made of chain mesh and they are towed by a fishing boat. Scallop dredging is very destructive to the seabed, and nowadays is often replaced by mariculture or by scuba diving to collect the scallops.

Fishing lines

Fish are caught with a fishing line by encouraging a fish to bite upon a fish hook or a gorge. A fishing hook will pierce the mouthparts of a fish and may be barbed to make escape less likely. A gorge is buried in the bait such that it would be swallowed end first. The the tightening of the line would fix it cross-wise in the quarry's stomach or gullet and so the capture would be assured. Fishing with a hook and line is called angling. Trolling is a technique in which a fishing lure on a line is drawn through the water. Trolling from a moving boat is a technique of big-game fishing and is used when fishing from boats to catch large open-water species such as tuna and marlin. Trolling is also a freshwater angling technique. Long-line fishing is a commercial fishing technique that uses hundreds or even thousands of baited hooks hanging from a single line.

Kite fishing

Kite fishing was invented in China and was (and is) also known to the people of New Guinea and other Pacific Islands. It is not clear whether kite fishing was communicated or of independent invention. Suitable kites may be of very simple construction. Those of Tobi Island are a large leaf stiffened by the ribs of the fronds of the coconut palm. The fishing line may be made from coconut fibre and the lure made from spiders webs. Kites can provide the boatless fishermen access to waters that would otherwise be available only to boats. Similarly, for boat owners, kites provide a way to fish in areas where it is not safe to navigate such as shallows or coral reefs where fish may be plentiful. Kites can also be used for trolling a lure through the water.

Ice fishing

See main article Ice fishing. Ice fishing is the practice of catching fish with lines and hooks through an opening in the ice on a frozen body of water. It is practiced by hunter-gatherers such as the Inuit and by sportsmen in many cold climates.

Fish traps

Traps are culturally almost universal and seem to have been independently invented many times. There are essentially two types of trap, a permanent or semi-permanent structure placed in a river or tidal area and pot-traps that are baited to attract prey and periodically lifted. Indigenous Australians were, prior to European colonisation, most populous in Australia's better-watered areas such as the Murray-Darling river system of the south-east. Here, where water levels fluctuate seasonally, indigenous people constructed ingenious, stone, fish traps. Unfortunately most have been completely or partially destroyed. The largest and best known were the Brewarrina fish traps on the Barwon River at Brewarrina in New South Wales, which fortunately are at least partly preserved [http://www.deh.gov.au/heritage/national/sites/brewarrina.html]. The Brewarinna fish traps caught huge numbers of migratory native fish as the Barwon River rose in flood and then fell. In southern Victoria, indigenous people created an elaborate systems of canals, some more than 2 km long. The purpose of these canals was the encouragement and catching of eels, a fish of short coastal rivers (as opposed to rivers of the Murray-Darling system). The eels were caught by a variety of traps including stone walls constructed across canals with a net placed across an opening in the wall. Traps at different levels in the marsh came into operation as the water level rose and fell. Somewhat similar stone wall traps were constructed by native American Pit River people in north-eastern California. [http://www.primitiveways.com/ajumawi_fish_traps.html] In medieval Europe, large fishing weir structures were constructed from wood posts and wattle fences. 'V' shaped structures in rivers could be as long as 60 m and worked by directing fish towards fish traps or nets. Such fish traps were evidently controversial in medieval England. The Magna Carta includes a clause requiring that they be removed: :All fish-weirs shall be removed from the Thames, the Medway, and throughout the whole of England, except on the sea coast. [http://www.fordham.edu/halsall/source/magnacarta.html] Basket weir fish traps were widely used in ancient times. They are shown in medieval illustrations and surviving examples have been found. Basket weirs are about 2 m long and comprise two wicker cones, one inside the other — easy to get into and hard to get out. [http://www.le.ac.uk/ulas/annualreports/ar99-00/hemington/hemington.html] Magna Carta The Wagenya people, in the Democratic Republic of Congo, build a huge system of wooden tripod across the river. These tripods are anchored on the holes naturally carved in the rock by the water current. To these tripods are anchored large baskets, which are lowered in the rapids to “sieve” the waters for fish. It is a very selective fishing, as these baskets are quite big and only large size fish are entrapped. Twice a day the adults Wagenya people pull out these baskets to check if there is any fish caught; in which case somebody will dive into the river to fetch it. Pot traps are typically used to catch crustaceans such as crabs, lobsters and crayfish. Pot traps such as the lobster trap may be constructed in various shapes, each is a mesh box designed with a convoluted entrance that makes entry much easier than exit. The pots are baited and lowered into the water and checked daily. Similar traps are used in many areas to capture bait fish.

Trained animals

bait fish In China and Japan, the practice of cormorant fishing is thought to date back some 1300 years. Fishermen use the natural fish-hunting instincts of the cormorants to catch fish, but a metal ring placed round the bird's neck prevents large, valuable fish being swallowed. The fish are instead collected by the fisherman. [http://www.city.gifu.gifu.jp/kankou/08_eng_01.html] The practice of tethering a remora, a sucking fish, to a fishing line and using the remora to capture sea turtles probably originated in the Indian Ocean. The earliest surviving records of the practice are Peter Martyr d'Anghera's 1511 accounts of the second voyage of Columbus to the New World (1494)[http://www.gutenberg.org/files/12425/12425-h/12425-h.htm]. However, these accounts are probably apocryphal, and based on earlier accounts no longer extant. Dating from the 1500s in Portugal, Portuguese Water Dogs were used by fishermen to send messages between boats, to retrieve fish and articles from the water, and to guard the fishing boats.

Toxins

Many hunter gatherer cultures use poisonous plants to stun fish so that they become easy to collect by hand. Some of these poisons paralyze the fish, others are thought to work by removing oxygen from the water. [http://tk.agron.ntu.edu.tw/Segawa1/fishing_poison.htm] Cyanides are used to capture live fish near coral reefs for the aquarium and seafood market. This illegal fishing occurs mainly in or near the Philippines, Indonesia, and the Caribbean to supply the 2 million marine aquarium owners in the world. Many fish caught in this fashion die either immediately or in shipping. Those that survive often die from shock or from massive digestive damage. The high concentrations of cyanide on reefs so harvested damages the coral polyps and has also resulted in cases of cyanide poisoning among local fishermen and their families.

Explosives

Dynamite or blast fishing, is done easily and cheaply with dynamite or homemade bombs made from locally available materials. Fish are killed by the shock from the blast and are then skimmed from the surface or collected from the bottom. The explosions indiscriminately kill large numbers of fish and other marine organisms in the vicinity and can damage or destroy the physical environment. Explosions are particularly harmful to coral reefs[http://stigmes.gr/br/brpages/articles/dinambr.htm]. Blast fishing is also illegal in many waterways around the world.

Modern fishing

Recreational fishing

homemade bombs Main article Angling Recreational fishing and the closely related (nearly synonymous) sport fishing describe fishing for pleasure or competition. Recreational fishing has conventions, rules, licensing restrictions and laws that limit the way in which fish may be caught. Typically, these prohibit the use of nets and the catching of fish with hooks not in the mouth. The most common form of recreational fishing is done with a rod, line and hooks attached to any of a wide range of lures or baits. This practice is known as angling. One method of growing popularity is kayak fishing. Kayak fisherman fish from sea kayaks in an attempt to level the playing field with fish and to further challenge their abilities. Kayaks are extremely stealthy and can allow anglers to reach areas unfishable from land or by conventional boat. In angling, it is sometimes expected or required that fish all be returned to the water (catch and release). The practice, however, is viewed by some with disapproval as they consider it unethical to inflict pain on a fish for fun or sport and not for reasons of capturing food. Anglers deny this charge, pointing out that fish commonly feed on hard and spiky prey items, and as such can be expected to have tough mouths, and also that some fish will re-take a lure they have just been hooked on, a behaviour that is unlikely if being hooked was painful. In a real sense, the suitability of catch and release is an ethical consideration and, as such, a science-based conclusion on the issue is unavailable. However, a variety of scientific studies have recorded very high survival rates (in excess of 90%) for caught and released fish, especially if the fish are carefully handled and barbless hooks and artificial lures are used. Proponents of catch and release also contend that the practice is increasingly necessary in order to conserve fish stocks in the face of burgeoning human populations, mounting fishing pressure and worsening habitat degradation. Opponents would prefer to ban or to severely restricting angling, a suggestion most anglers find unpalatable. Recreational fishermen can have profound deleterious effects on fish stocks, particularly those of large, slow growing species. The only way for growing numbers of recreational fishermen to continue fishing is to reduce their impact on fish populations. Catch and release, in combination with techniques such as strong tackle (to get fish in quickly, for release in good condition), careful handling of fish and barbless hooks (to reduce physical damage), may be useful tools in this endeavour. A recent phenomenon of recreational fishing are fishing competitions (tournaments) where fishermen compete for prizes based on the total weight of a given species of fish caught within a predetermined time. This sport evolved from local fishing contests into large competitive circuits, especially in North America. Competitors are most often professional fishermen who are supported by commercial endorsements. Big-game fishing describes fishing from boats to catch large open-water species such as tuna, sharks and marlin. Noodling and Trout tickling may be pursued as a recreation. Laws made to control recreational fishing laws frequently also attempt to control the harvest of other aquatic species, such as frogs and turtles.

Commercial fishing

turtle, north-west Scotland.]] Main article Fishing industry Commercial fishing provides a large quantity of food to many countries around the world, but those who pursue it as an industry must often pursue fish far into the ocean under adverse conditions. Commercial fishermen harvest almost all aquatic species, from tuna, cod and salmon to shrimp, krill, lobster, clams, squid and crab. Commercial fishing methods have become very efficient using large nets and sea-going processing factories. Many new restrictions are often integrated with varieties of fishing allocation schemes (quotas), and international treaties that have sought to limit the fishing effort and, sometimes, capture efficiency. Fishing methods vary according to the region, the species being fished for, and the technology available to the fishermen. A commercial fishing enterprise may vary from one man with a small boat with hand-casting nets or a few pot traps, to a huge fleet of trawlers processing tons of fish every day. Some common commercial techniques today are trawling, seining, driftnetting, handlining, longlining, gillnetting, and diving. Also see Krill fishery.

Preservation

Image:Fish Packed in Ice.jpg|Fish packed in ice. Image:Canned fish 2.JPG|Canned fish. Image:Hjell-oversikt.arj.jpeg|A fish-drying rack. Hovden in Norway. image:Kipper.JPG|Kipper: salted and smoked herring. Image:Klippfiskproduksjon.jpg|Salting of fish in factory. Ancient methods of preserving fish included drying , salting, pickling and smoking. All of these techniques are still used today but the more modern techniques of freezing and canning have taken on a large importance. See:
- Haddock: Arbroath Smokie (lightly smoked).
- Herring: kipper (salted and smoked), surströmming (fermented), rollmops (pickled), soused (salted).
- Salmon: smoked salmon, cured salmon, and gravlax (fermented).
- Cod: stockfish (air dried), lutefisk (soaked in lye). In the past, fishing vessels were restricted in range by the simple consideration that the catch must be returned to port before it spoils and becomes worthless. The development of refrigeration and freezing technologies transformed the commercial fishing industry: fishing vessels could be larger, spending more time away from port and therefore accessing fish stocks at a much greater distance. Refrigeration and freezing also allow the catch to be distributed to markets further inland, reaching customers who previously would have had access only to dried or salted sea fish. Canning, developed during the 19th century has also had a significant impact on fishing by allowing seasonal catches of fish that are possibly far from large centres of population to be exploited. For example: sardines.

Fish products

Food

Image:Fried Fish and French Fries.jpg|Fried fish & French fries (fish & chips). Image:Kräftskiva-2.jpg|Crayfish and prawns. Image:Korea style raw fish.jpg|Korean style raw fish. Image:Cooked mussels DSC09244.JPG|Cooked mussels. The flesh of many fish are primarily valued as a source of food; there are many edible species of fish as well as other sea food. Shellfish include shelled molluscs and crustaceans used as food. Shelled molluscs include the clam, mussel, oyster, winkle and scallop; some crustaceans are the shrimp, lobster, crayfish, and crab. Eggs, called roe, of various species may be eaten; roe comes from fish and certain marine invertebrates, such as sea urchins and shrimp. In some cultures, roe is considered a delicacy, for example caviar from the sturgeon. Squid and octopus are valued as food. Sea cucumber is considered a delicacy in Chinese cooking and is often served at New Year’s feasts, usually in soups. [http://www.asiafood.org/glossary_2.cfm] In some cultures, for example China, Japan, and Vietnam, certain species of jellyfish are consumed. [http://www.asiafood.org/glossary_1.cfm?alpha=J&wordid=2696&startno=1&endno=25] Fish oil is valued as a dietary supplement.

Live fish

Live fish are collected for the international live food fish trade. Some seafood restaurants keep live fish in aquaria for display or for cultural beliefs. The majority of live fish kept at seafood restaurants, however, are desired for the freshness of the seafood, being killed only immediately before being cooked. Suiting customer preference, this practice makes the seafood higher in quality and better in taste. The prevalence of cultural beliefs and consumer standards helps to drive the demand for the live food fish trade. Hong Kong, for example, is estimated to have imported in excess of 15,000 tonnes of live food fish in 2000. This brought the value of their live food fish trade industry to US$400 million as reported by the [http://marine.wri.org/pubs_content_text.cfm?ContentID=645 World Resources Institute]. Fish can also be collected in ways that do not injure them such as in a seine net or by placing an electric current into the water. Such techniques are used most often by researchers for observation and study but are also used by those who collect fish for the aquarium trade. There are several organizations devoted to improving the methods of collecting, handling, transporting, exporting and farming of wild and domesticated live food fish, as well as freshwater and marine tropical fish destined for aquaria.

Other products

Pearls and mother-of-pearl are valued for their lustre. Traditional methods of pearl hunting are now virtually extinct. Sharkskin and rayskin which are covered with, in effect, tiny teeth (dermal denticles) were used for the purposes that sandpaper currently is. These skins are also used to make leather. Sharkskin leather is used in the manufacture of hilts of traditional Japanesse swords. Sea horse, star fish, sea urchin and sea cucumber are used in traditional Chinese medicine. Tyrian purple is a pigment made from marine snails Murex brandaris and Murex trunculus. Sepia is a pigment made from the inky secretions of cuttlefish. Fish glue is made by boiling the skin, bones and swim bladders of fish. Fish glue has long been valued for its use in all manner of products from illuminated manuscripts to the Mongolian war bow. Isinglass is a substance obtained from the swim bladders of fish (especially sturgeon), it is used for the clarification of wine and beer. Fish emulsion is a fertilizer emulsion that is produced from the fluid remains of fish processed for fish oil and fish meal industrially.

Cultural references

Fishing is a widely used as a metaphor though as such it is possibly ambiguous. On the one hand, fishing with a net has nuances of gathering by honest effort. For example, in the New Testament, Jesus is reported to have said to his disciples: Follow me, and I will make you fishers of men. [http://en.wikisource.org/wiki/Bible,_English,_King_James,_Matthew#Chapter_4 Matthew 4:19]. On the other hand, fishing with bait or lure sometimes has nuances of catching by deception, possibly with an implication of greed on the part of the victim. For example, the expression "fishing expedition" (usually used to describe a line of questioning), describes a case where the questioner implies that he knows more than he actually does in order to trick the target into divulging more information than he wishes to reveal. Other examples of fishing terms that carry a negative connotation are: "fishing for compliments", "to be fooled hook, line and sinker" (to be fooled beyond merely "taking the bait"), and the internet scam of Phishing.

External links

Tides

The tide is the regular rising and falling of the ocean's surface caused by changes in gravitational forces external to the Earth. The main changing gravitational field is due to the Moon while a lesser field is caused by the Sun. Since tides generate currents of conducting fluids within the Earth's magnetic field, they affect in return the magnetic field itself. The loss of rotational energy of the earth, due to friction within the tides, and the gravitational effects caused by tidal deformations of the earth's body, are responsible for the slowdown of the earth's rotation and the increase of the distance to the moon, see Tidal force.

Tidal terminology

Tidal force Tidal force The maximum water level is called "high tide" or "high water" and the minimum level is "low tide" or "low water". High water occurs as two bulges in the height of the oceans; one bulge faces the moon and the other, on the opposite side of the earth, faces away from the moon. For an explanation see below under Tidal physics. There are two low waters positioned at about 90° of longitude from the high waters. At any given point on the ocean, there are normally two high tides and two low tides each day. The common names of the two high tides are the "high high" tide and the "low high" tide; the two low tides are called the "high low" tide and the "low low" tide. On average, high tides occur 12 hours 24 minutes apart. The 12 hours is due to the Earth's rotation, and the 24 minutes to the Moon's orbit. The 12 hours is half of a solar day and the 24 minutes is half of a lunar extension, which is 1/ (29-day lunar cycle). The lunar cycle is what is tracked by tide clocks. The time between high tide and low tide, when the water level is falling, is called the "ebb". The time between low tide and high tide, when the tide is rising, is called "flow" or "flood". tide clock The height of the high and low tides (relative to mean sea level) also varies. Around new and full Moon when the Sun, Moon and Earth form a line, the tidal forces due to the Sun reinforce those of the Moon, due to the syzygy found at those times. The tides' range is then at its maximum: this is called the "spring tide", or just "springs" and is derived not from the season of spring but rather from the German verb springen, meaning "to leap up". When the Moon is at first quarter or third quarter, the sun and moon are at 90° to each other and the forces due to the Sun partially cancel out those of the Moon. At these points in the Lunar cycle, the tide's range is at its minimum: this is called the "neap tide", or "neaps". Spring tides result in high waters that are higher than average, low waters that are lower than average, slack water time that is shorter than average and stronger tidal currents than average. Neaps result in less extreme tidal conditions. Normally there is a seven day interval between springs and neaps. The relative distance of the Moon from the Earth also affects tide heights: When the Moon is at perigee the range increases, and when it is at apogee the range is reduced. Every 7½ lunations, perigee and (alternately) either a new or full Moon coincide; at these times the range of tide heights is greatest of all, and if a storm happens to be moving onshore at this time, the consequences (in the form of property damage, etc.) can be especially severe (surfers are aware of this, and will often intentionally go out to sea during these times, as the waves are more spectacular than ever). The effect is enhanced even further if the line-up of the Sun, Earth and Moon is so exact that a solar or lunar eclipse occurs concomitant with perigee.

Timing

In most places there is a delay between the phases of the Moon and its effect on the tide. Springs and neaps in the North Sea, for example, are two days behind the new/full Moon and first/third quarter, respectively. The reason for this is that the tide originates in the southern oceans, the only place on the globe where a circumventing wave (as caused by the tidal force of the Moon) can travel unimpeded by land. The resulting effect on the amplitude, or height, of the tide travels across the oceans. It is known that it travels as a single broad wave pulse northwards over the Atlantic. This causes relatively low tidal ranges in some locations (nodes) and high ones in other places. This is not to be confused with tidal ranges caused by local geography, as can be found in Nova Scotia, Bristol, the Channel Islands, and the English Channel. In these places tidal ranges can be over 10 metres. The Atlantic tidal wave arrives after approximately a day in the English Channel area of the European coast and needs another day to go around the British Isles in order to have an effect in the North Sea. Peaks and lows of the Channel wave and North Sea wave meet in the Strait of Dover at about the same time but generally favour a current in the direction of the North Sea. The exact time and height of the tide at a particular coastal point is also greatly influenced by the local topography. There are some extreme cases: the Bay of Fundy, on the east coast of Canada, features the largest well-documented tidal ranges in the world, 16 metres (53 feet), because of the shape of the bay. Southampton in the United Kingdom has a double high tide caused by the flow of water around the Isle of Wight, and Weymouth, Dorset has a double low tide because of the Isle of Portland. Ungava Bay in Nunavut, north eastern Canada, is believed by some experts to have higher tidal ranges than the Bay of Fundy (about 17 metres or 56 feet), but it is free of pack ice for only about four months every year, whereas the Bay of Fundy rarely freezes even in the winter. There are only very slight tides in the Mediterranean Sea and the Baltic Sea due to their narrow connections with the Atlantic Ocean. Extremely small tides also occur for the same reason in the Gulf of Mexico and Sea of Japan. On the southern coast of Australia, because the coast is extremely straight (partly due to the tiny quantities of runoff flowing from rivers), tidal ranges are equally small.

Tidal physics

Ignoring external forces, the ocean's surface defines a geopotential surface or geoid, where the gravitational force is directly towards the centre of the Earth and there is no net lateral force and hence no flow of water. Now consider the effect of added external, massive bodies such as the Moon and Sun. These massive bodies have strong gravitational fields that diminish with distance in space. It is the spatial differences in these fields that deform the geoid shape. This deformation has a fixed orientation relative to the influencing body and the rotation of the Earth relative to this shape drives the tides around. Gravitational forces follow the inverse-square law (force is inversely proportional to the square of the distance), but tidal forces are inversely proportional to the cube of the distance. The Sun's gravitational pull on Earth is 179 times bigger than the Moon's, but because of its much greater distance, the Sun's tidal effect is smaller than the Moon's (about 46% as strong). For simplicity, the next few sections use the word "Moon" where also "Sun" can be understood. cube, this diagram shows the Moon's gravity differential over the thickness of the shell.]] cube at the surface of the earth is known as the Tidal Generating Force. This is the primary mechanism that drives tidal action and explains two bulges, accounting for two high tides per day. Other forces, such as the Earth and Moon revolving around each other, and the Sun's gravity also add to tidal action.]]
Since the Earth's crust is solid, it moves with everything inside as one whole, as defined by the average force on it. For a geoid shape this average force is equal to the force on its centre. The water at the surface is free to move following forces on its particles. It is the difference between the forces at the Earth's centre and surface which determine the effective tidal force. At the point right "under" the Moon (the sub-lunar point), the water is closer than the solid Earth; so it is pulled more and rises. On the opposite side of the Earth, facing away from the Moon (the antipodal point), the water is farther than the solid earth, so it is pulled less and moves away from Earth, rising as well. On the lateral sides, the water is pulled in a slightly different direction than at the centre. The vectorial difference with the force at the centre points almost straight inwards to Earth. It can be shown that the forces at the sub-lunar and antipodal points are approximately equal and that the inward forces at the sides are about half that size. Somewhere in between there is a point where the tidal force is parallel to the Earth's surface. Those parallel components actually contribute most to the formation of tides, since the water particles are free to follow. The actual force on a particle is only about a ten millionth of the force caused by the Earth's gravity. These minute forces all work together:
- pull up under and away from the Moon
- pull down at the sides
- pull towards the sub-lunar and antipodal points at intermediate points So two bulges are formed pointing towards the Moon just under it and away from it on Earth's far side.

Tidal amplitude and cycle time

Since the Earth rotates relative to the Moon in one lunar day (24 hours, 48 minutes), each of the two bulges travels around at that speed, leading to one high tide every 12 hours and 24 minutes. The theoretical amplitude of oceanic tides due to the Moon is about 54 cm at the highest point. This is the amplitude that would be reached if the ocean were uniform with no landmasses and Earth not rotating. The Sun similarly causes tides, of which the theoretical amplitude is about 25 cm (46% of that of the Moon) and the cycle time is 12 hours. At spring tide the two effects add to each other to a theoretical level of 79 cm, while at neap tide the theoretical level is reduced to 29 cm. Real amplitudes differ considerably, not only because of global topography as explained above, but also because the natural period of the oceans is in the same order of magnitude as the rotation period: about 30 hours (by comparison, the natural period of the Earth's crust is about 57 minutes). This means that, if the Moon suddenly vanished, the level of the oceans would oscillate with a period of 30 hours with a slowly decreasing amplitude while dissipating the stored energy. This 30 hour value is a simple function of terrestrial gravity and the average depth of the oceans. The distances of Earth from the Moon or the Sun vary, because the orbits are not circular, but elliptical. This causes a variation in the tidal force and theoretical amplitude of about ±18% for the Moon and ±5% for the Sun. So if both are in closest position and aligned, the theoretical amplitude would reach 93 cm.

Tidal lag

Because the Moon's tidal forces drive the oceans with a period of about 12.42 hours (half of the Earth's synodic period of rotation), which is considerably less than the natural period of the oceans, complex resonance phenomena take place. The lag between the Moon's passage and the tidal response varies between 2 hours in the southern oceans, to two days in the North Sea. The global average tidal lag is six hours (which means low tide occurs when the Moon is at its zenith or its nadir, a result that goes against common intuition). Tidal lag and the transfer of momentum between sea and land causes the Earth's rotation to slow down and the Moon to be moved further away in a process known as tidal acceleration.

Alternative explanation

tidal acceleration Some other explanations in articles on the physics of tides include the (apparent) centrifugal force on the Earth in its orbit around the common centre of mass (the barycentre) with the Moon. The barycentre is located at about ¾ of the radius from the Earth's centre. It is important to note that the Earth has no "rotation" around this point. It just "displaces" around this point in a circular way (see figure). Every point on Earth has the same angular velocity and the same radius of orbit, but with a displaced centre. So the centrifugal force is uniform and does not contribute to the tides. However, this uniform centrifugal force is just equal (but with opposite sign) to the gravitational force acting on the centre of mass of Earth. So subtracting the gravitational force at the centre of Earth from the local gravitational forces at the surface, has the same effect as adding the (uniform) centrifugal forces. Although these two explanations seem very different, they yield the same results.

Tides & fluids

Tides and tidal effects happen in general whenever a mass with some volume moves in a gravitational field that is not uniform. This is, they always happen. For example, in one way or the other, all objects moving in space will see some form of tidal forces. By acting on an ideal rigid body, by definition tides will not deform the body. Many bodies which are moving within the solar system, for example, are not rigid but merely balls of gas or fluids, hovering in empty space (Sometimes they have a very thin solid crust). Tidal forces generate pressure differences between different volumes within such objects, and thus generate material currents on or within such bodies. The following argument applies in general to all such bodies, but the discussion here is restricted to a simplified Earth - Moon system (the sun also generates tides in real life, which are about half as strong as the moon's tides). The moon's tidal effects generate an acceleration field at the surface regions of the earth which point in its direction or the opposite direction. This field is equivalent in strength to the weight of one tenth of a microgram per kilogram material. In other words, each kilogram of material at the surface of the earth experiences an "upward" force that is equivalent to the weight of one tenth of a microgram. It is perfectly clear that nothing starts to move upward because of this. What happens instead, especially within fluids, is a change in the statical pressure within the fluid, because the masses on top lose a little bit of weight. There will be a pressure difference to neighbouring regions, and a material current will start to flow into this regions, until the pressure difference due to tide is balanced by a higher level of the fluids surface. In the earth's oceans, the secondary effects of the material currents amplify the tidal effects by as much as a factor of 20. An equipotential surface of the ocean in a tide region would be 2 ft (60 cm) above normal level, but some coastlines experience tides of 40 ft (12 m) or more. It is important to notice that pressure differences and thus material currents are not only generated in the earth's oceans, but in the interior of the earth as well. By the MHD effect, the material currents generated by the tides will also affect the earth's electromagnetic field. This is seen in real life. The tides continuously excite (seismic) waves within the earth which can be measured by seismology.

Tides and navigation

Tidal flows are of profound importance in navigation and very significant errors in position will occur if tides are not taken into account. Tidal heights are also very important; for example many rivers and harbours have a shallow "bar" at the entrance which will prevent boats with significant draught from entering at certain states of the tide. Tidal flow can be found by looking at a tidal chart or tidal stream atlas for the area of interest. Tidal charts come in sets, each diagram of the set covering a single hour between one high tide and another (they ignore the extra 24 minutes) and give the average tidal flow for that one hour. An arrow on the tidal chart indicates direction and two numbers are given: average flow (usually in knots) for spring tides and neap tides respectively. If a tidal chart is not available, most nautical charts have "tidal diamonds" which relate specific points on the chart to a table of data giving direction and speed of tidal flow. Standard procedure is to calculate a "dead reckoning" position (or DR) from distance and direction of travel and mark this on the chart (with a vertical cross like a plus sign) and then draw in a line from the DR in the direction of the tide. Measuring the distance the tide will have moved the boat along this line then gives an "estimated position" or EP (traditionally marked with a dot in a triangle). Nautical charts display the "charted depth" of the water at specific locations and on contours. These depths are relative to "chart datum", which is the level of water at the lowest possible astronomical tide (tides may be lower or higher for meteorological reasons) and are therefore the minumum water depth possible during the tidal cycle. "Drying heights" may also be shown on the chart. These are the heights of the exposed seabed at the lowest astronomical tide. Heights and times of low and high tide on each day are published in "tide tables". The actual depth of water at the given points at high or low water can easily be calculated by adding the charted depth to the published height of the tide. The water depth for times other than high or low water can be derived from tidal curves published for major ports. If an accurate curve is not available, the rule of twelfths can be used. This approximation works on the basis that the increase in depth in the six hours between low and high tide will follow this simple rule: first hour - 1/12, second - 2/12, third - 3/12, fourth - 3/12, fifth - 2/12, sixth - 1/12. (N.B. It would be foolish to attempt navigation without some training and the "Rule of Twelfths " in particular should be used with caution)

Other tides

In addition to oceanic tides, there are atmospheric tides as well as terrestrial tides (land tides), affecting the rocky mass of the Earth. Atmospheric tides may be negligible for everyday phenomena, drowned by the much more important effects of weather and the solar thermal tides. However, there is strictly no upper limit to the Earth's atmosphere, and the tidal pull increases with the distance from the Earth's centre. Theoretically, the Earth's atmosphere extends beyond the Roche limit of the Earth in the Moon's gravitational field. Since the outer extremely thin layers of the atmosphere are in equilibrium with the layers below, the long term effects may not be easily neglected. This means, if the extremely thin outer layers are steadily siphoned away, the material is re-supplied by lower layers, causing an altogether constant small loss of material. The Earth's crust, on the other hand, rises and falls imperceptibly in response to the Moon's solicitation. The amplitude of terrestrial tides can reach about 55 cm at the equator (15 cm of which are due to the Sun), and they are nearly in phase with the Moon (the tidal lag is about two hours only) - which means that they reinforce the apparent oceanic tides. While negligible for most human activities, terrestrial tides need to be taken in account in the case of some particle physics experimental equipments ([http://news-service.stanford.edu/news/2000/march29/linac-329.html Stanford online]). For instance, at the CERN or SLAC, the very large particle accelerators are designed while taking terrestrial tides into account for proper operation. Indeed, despite their kilometre-range dimension, centimetric deformations might lead to their malfunctioning as a physics experimental apparatus. Among the effects that need to be taken into account are : [http://accelconf.web.cern.ch/accelconf/e00/PAPERS/MOP5A04.pdf circumference deformation] for circular accelerators, [http://accelconf.web.cern.ch/accelconf/p93/PDF/PAC1993_0044.PDF particle beam energy]. The first mathematical explanation of tidal forces was given in 1687 by Isaac Newton in the Philosophiae Naturalis Principia Mathematica. Yet [http://it.wikipedia.org/wiki/Lucio_Russo Lucio Russo], an Italian scholar, in his book [http://www.feltrinelli.it/SchedaLibro?id_volume=5000104 Flussi e Riflussi] (yet to be published in English) demonstrates that hellenistic Greeks already had understood tides in terms of the gravitational pull of the Moon and the Sun. In particular it emerges that Seleuc of Babylon (2 B.C.) used his gravitational explanation to prove that it was the Earth to revolve around the Sun, not the opposite. Tsunami, the large waves that occur after earthquakes, are sometimes called tidal waves, but have nothing to do with the tides. Other phenomena unrelated to tides but using the word tide are rip tide, storm tide, hurricane tide, and red tide. The term tidal wave appears to be disappearing from popular usage.

External links

- [http://www.jal.cc.il.us/~mikolajsawicki/Tides_new2.pdf "Myths about Gravity and Tides" - an extended and revised version of the paper originally published in “The Physics Teacher” 37, October 1999, pp. 438 - 441.]
- [http://www.lhup.edu/~dsimanek/scenario/tides.htm Misconceptions about tides]
- [http://www.co-ops.nos.noaa.gov/restles3.html Direct and opposite tides, from the Center for Operational Oceanographic Products and Services] (This site uses the concept of centrifugal force.)
- [http://aiuas3.unibe.ch/dpgm/zm_graph_tide.html Earth tides calculator] Category:Physical oceanography Category:Tide ko:조석현상 ja:潮汐 zh-min-nan:Lâu-chúi

Ordnance Survey

]] Ordnance Survey (OS) is an executive agency of the United Kingdom government. It is the national mapping agency for Great Britain , and one of the world's largest producers of maps. In addition to producing a wide range of maps of Great Britain, the organisation is also working in over sixty countries worldwide.

Origins

The roots of Great Britain's Ordnance Survey (OS) go back to 1747, when King George II of England commissioned a military survey of the Scottish highlands following the Jacobite revolt of 1745. William Roy was the engineer responsible for this pioneering work; one of the staff involved was noted artist Paul Sandby. It was not until 1790 that the Board of Ordnance (the predecessor of the Ministry of Defence) began a national military survey starting with the south coast of England in anticipation of a French invasion. By 1791, the Board had purchased the new Ramsden theodolite, and work commenced on mapping southern Britain using a baseline that Roy himself had previously measured and which crosses the present Heathrow Airport. In 1801 the first one-inch to the mile (1:63,360) map was published, detailing the county of Kent, with Essex following shortly after. EssexDuring the next twenty years approximately one-third of England and Wales was mapped at the same scale. (see Principal Triangulation of Great Britain.) It was gruelling work: Major Thomas Colby, later the longest serving Director General of the Ordnance Survey, walked 586 miles in 22 days on a reconnaissance in 1819. In 1824, Colby and most of his staff moved to Ireland to work on a six-inch to the mile (1:10,560) valuation survey. Colby was not only involved in the design of specialist measuring equipment. He also established a systematic collection of place names, and reorganised the map-making process to produce clear, accurate plans. He believed in leading from the front, travelling with his men, helping to build camps and, as each survey session drew to a close, arranging mountain-top parties with enormous plum puddings. After the first Irish maps began to come out in the mid-1830s, the Tithe Commutation Act led to calls for similar six-inch surveys in England and Wales. After official prevarication, the development of the railways added to pressure that resulted in the 1841 Ordnance Survey Act. This granted a right to enter property for the purpose of the survey. Following a fire at its headquarters at the Tower of London in 1841, the OS was in disarray for several years with arguments about which scales to use. Major-General Sir Henry James was now Director General, and he saw how photography could be used to make maps of various scales cheaply and easily. Due to the fire, the OS relocated to a site in Southampton, and the twenty-five inch to the mile survey was complete by 1895. Despite heavy bomb damage in World War II, the OS remained in Southampton until 1969.

The 20th century

1969During the First World War the OS was more involved in preparing maps of France and Belgium for its own use. Many more maps were created during World War II, including :
- 1:40,000 map of Antwerp, Belgium
- 1:100,000 map of Brussels, Belgium
- 1:5,000,000 map of South Africa
- 1:250,000 map of Italy
- 1:50,000 map of Northeast France
- 1:30,000 map of the Netherlands with manuscript outline of German Army occupation districts After the war Colonel Charles Close, the current Director General, developed a marketing strategy using covers designed by Ellis Martin to increase sales in the leisure market. In 1920 O. G. S. Crawford was appointed Archaeology Officer and played a prominent role in developing the use of aerial photography to deepen understanding of archaeology. The Davidson Committee was established in 1935 to review the Ordnance Survey's future. The new Director General, Major-General Malcolm MacLeod, started the retriangulation of Great Britain, an immense task which involved erecting concrete triangulation pillars (trig points) on prominent (often inaccessible) hilltops throughout Britain. These were intended to be infallibly constant positions for the theodolites during the many angle measurements, which were each repeated no less than 32 times. The Davidson Committee's final report set the OS on course for the twentieth century. The national grid reference system was launched, with the metre as its measurement. An experimental new 1:25,000 scale map was introduced. The one-inch maps remained for almost forty years before being superseded by the 1:50,000 scale series, as proposed by William Roy more than two centuries earlier. The OS had outgrown its site in the centre of Southampton (made worse by the bomb damage of the Second World War), and in 1969 moved to a site in the suburb of Maybush, towards the edge of the city, where it remains today. Some of the remaining buildings of the original city centre site are now used as part of the court complex. In 1995 the Ordnance Survey digitised the last of about 230,000 maps, making Britain the first country in the world to complete a programme of large-scale electronic mapping. The OS is now a civilian organisation with executive agency status.
UK Map Range
Ordnance Survey maps are available in most bookshops, in a variety of scales:
- Route (1:625,000) - Designed for long-distance road users. One double-sided map (dark blue cover) covers the whole of Great Britain.
- Road (1:250,000) - Designed for road users. They have green covers; 8 sheets cover the whole of Great Britain.
- Landranger (1:50,000) - The "general purpose" map. They have pink covers; 204 sheets cover the whole of Great Britain and the Isle of Man.
- Explorer (1:25,000) - Specifically designed for walkers and cyclists. They have orange covers; 403 sheets cover the whole of Great Britain (the Isle of Man is excluded from this series). Explorer maps have replaced two older series of 1:25,000 map:
- Outdoor Leisure - Also for walkers and cyclists. These 33 maps specifically covered tourist destinations. Identified by their yellow covers and often double-sided, they predated the Explorer maps. They covered a larger area than Pathfinders.
- Pathfinder - Pathfinders, with their green covers, were the predecessors to the Explorer series. These maps were smaller than the new ones and generally had no overlap between adjacent sheets, making them less convenient to use. There were over 1,300 maps in the series. Some Pathfinders were phased out by the arrival of Outdoor Leisure maps, the remainder being later replaced by the new Explorer series. Also produced are various historical and archaeological maps, and road maps of certain popular "tourist" areas, all at a variety of scales. The Ordnance Survey produces a free mapping index, showing which parts of the country are covered by which maps. The Ordnance Survey also produces more detailed mapping at 1:10,000 and 1:1,250 scales, which is available from some of the more specialist outlets. This is produced to order from digital data, so the customer can choose exactly which area the map should cover.
Cartography
Isle of Man] The original maps were made by triangulation. For the second survey, in 1935, this process was also used, and resulted in the building of many short (approx four feet high), square, triangulation points (trig points) - concrete pillars on top of various high points and the working out the exact position of these by triangulation. The details in between were then filled in with less precise methods. Modern Ordnance Survey maps are based on aerial photographs, but large numbers of the pillars, or trig points, remain. The OS still maintains a set of master geodetic reference points to tie the OS geographic datums to modern measurement systems including GPS. The Ordnance Survey maps of Great Britain do not use latitude and longitude to indicate position but a special grid. The grid is technically known as OSGB36 ™ (Ordnance Survey Great Britain 1936), and was introduced after the retriangulation of 1936–53.
OS MasterMap
The Ordnance Survey's flagship digital product, launched in November 2001, is OS MasterMap. This is a database that records every fixed feature of Great Britain larger than a few metres in one continuous digital map. Every feature is given a unique TOID (topographical identifier), a simple identifier that includes no semantic information. Typically each TOID is associated with a polygon that represents the area on the ground that the feature covers, in National Grid coordinates. MasterMap is offered in themed "layers", for example, a road layer and a building layer, each linked to a number of TOIDs. Pricing of licenses to MasterMap data depends on the total area requested, the layers licensed, the number of TOIDs in the layers, and the period in years of the data usage. MasterMap can be used to generate maps for a vast array of purposes. Although the scale on a digital map is much more flexible than a paper map, one can print out maps from MasterMap data with detail equivalent to a traditional 1:1250 paper map. The OS claims that MasterMap data is never more than 6 months out of date, thanks to continuous review. The scale and detail of this mapping project is so far unique. Around 440 million TOIDs have so far been assigned, and the database stands at 600 gigabytes in size. MasterMap is currently (August 2005) at version 6. The OS is encouraging users of its old OS Landline data to migrate to MasterMap.
See also

- Equivalent agencies elsewhere
- Ordnance Survey Ireland
- Ordnance Survey of Northern Ireland
- Institut géographique national France ([http://fr.wikipedia.org/wiki/Institut_g%C3%A9ographique_national IGN on Wiki FR])
- Topografische Dienst Kadaster the Netherlands ([http://nl.wikipedia.org/wiki/Topografische_Dienst_Kadaster (TDK on Wiki NL])
- Swisstopo – Switzerland
- Grid reference
- British national grid reference system
- Irish national grid reference system
- Cartography (map making)
- Hydrography
- Hydrographic survey
- United Kingdom Hydrographic Office
- Romer
- Sea level
- UK topics
- Maps of the UK and Ireland
References

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External links

- [http://www.ordnancesurvey.gov.uk/ Ordnance Survey]
- [http://www.old-maps.co.uk/ old-maps.co.uk] 19th century Ordnance Survey maps of the whole of Great Britain
- [http://www.lancashire.gov.uk/environment/oldmap/index.asp 19th century Ordnance Survey maps of Lancashire]
- [http://www.gps.gov.uk/guidecontents.asp National GPS network information: A guide to coordinate systems in Great Britain]
- [http://www.ordnancesurvey.co.uk/oswebsite/products/osmastermap/ OS MasterMap official site]
- [http://www.guardian.co.uk/uk_news/story/0,3604,1164335,00.html The Guardian: Devil is in the detail as OS maps out the future by Paul Brown, March 8, 2004]
- [http://www.cadserver.co.uk/common/viewer/archive/2004/Dec/20/news2.phtm CADserver: AEC Feature: Master and servant, Nov/Dec 2004]
Footnote
# Note that the Ordnance Survey currently deals only with maps of Great Britain (and to an extent, the Isle of Man). Northern Ireland, whilst an integral part of the United Kingdom, is mapped by a separate government agency, the Ordnance Survey of Northern Ireland. Category:Geography of the United Kingdom Category:Land surveying systems Category:Cartography Category:Executive agencies of the United Kingdom government

Cartography

Cartography or mapmaking (in Greek chartis = map and graphein = write) is the study and practice of making maps or globes. Maps have traditionally been made using pen and paper, but the advent and spread of computers has revolutionized cartography. Most commercial quality maps are now made with map making software that falls into one of three main types; CAD, GIS, and specialized map illustration software. Maps function as visualization tools for spatial data. Spatial data is acquired from measurement and can be stored in a database, from which it can be extracted for a variety of purposes. Current trends in this field are moving away from analog methods of mapmaking and toward the creation of increasingly dynamic, interactive maps that can be manipulated digitally. The cartographic process rests on the premise that there is an objective reality and that we can make reliable representations of that reality by adding levels of abstraction.

History

database Mapmaking involves advanced skills and attitudes, particularly the use of symbols to represent certain geographic phenomena, as well as the ability to visualize the world in an abstract and scaled down form. Maps have been an integral part of the human story for long time (maybe 8,000 years - nobody knows exactly, but longer than a written words). From cave/wall partings, ancient maps of Babylon and Greek philosophers, through the Age of Exploration, and on into the 21st century, people have created and used maps as the essential tools to help them define, explain and navigate their way through the world (and beyond). According to some scholars, mapping represented a significant step forward in the intellectual development of human beings and it serves as a record of the advancing knowledge of the human race. The oldest extant picture that resembles a map was created in the late 7th millennium BCE in Anatolia, modern Turkey. This wall painting [http://www.henry-davis.com/MAPS/Ancientimages/100B.jpeg]represents a plan of an early-civilized city that prospered by trading obsidian. Whoever created this ‘mental map’ may have been encouraged by the fact that houses in Çatal Hűyűk were clustered together and were entered via flat roofs. Therefore, it was normal for the inhabitants to view their city from a bird’s eye view. Having said this, I think that this painting influenced in some way all-later civilizations with their mapmaking endeavours. Today, almost all maps are drawn as if we are looking down from the sky instead of from the more natural horizontal or oblique perspective. Nevertheless, one of the early-survived Hellenic ‘quasi-maps’ of the Minoan civilization on Crete, the so-called “House of the Admiral” c. 1600 BCE is a wall painting representing view of a seaside community in an oblique perspective. Predecessors of mapping could be also found in Babylonia around the 23rd century BCE. An engraved map of the holy city of Nippur, from the Kassite period (14th – 12th centuries BCE) of Babylonian history, was found at Nippur [http://www-oi.uchicago.edu/OI/PROJ/NIP/PUB93/NSC/NSCFIG7.html]. The early attempts at maps were severely limited by lack of knowledge of anything other than very local features. Whereas early world maps reflected mostly religious beliefs of the form of the world. For example, the Babylonian World Map -- the earliest surviving map of the world (c. 600BCE) -- is very much Mesopotamia-centred, ignoring peoples such as the Persians and Egyptians, who were well known to the Babylonians. The area shown is depicted as a circular shape surrounded by water, which fits the religious image of the world in which the Babylonians believed. Maps were quite rare in ancient Egypt. The Egyptians seem to have preferred written words to plans. Still, what might have later influenced human mapmaking were the geometrical methods that were used for land measurements, which were stimulated by the need to re-establish the exact boundaries of properties after the annual Nile floods. The most interesting artefact that has survived from this period is the Turin Papyrus, dated c. 1300 BCE. It shows the mountains east of the Nile where gold and silver were mined, along with the location of the miners’ shelters, wells, and the road network that linked the region with the mainland. Its originality can be seen in the map’s inscriptions, its precise orientation and the use of colour. Ancient Greeks were the first people to adopt a scientific approach to mapping. They were excellent observers of natural phenomena. Observations of the sun, the moon, and the curvature of the earth were fundamental to the theoretical thinking of early Greek philosophers, scientists, and geographers. The Greeks’ philosophical conception of the world and their growing knowledge in geography contributed to establishing the concept of mapmaking and to the development of cartographic techniques. This chapter presents one of the most momentous periods in the history of cartography by illustrating the works of early Greek philosophers who pioneered the concept of mapping. It traces the evolution of Greek ideas concerning the geography of the earth and cartographic techniques of representing natural phenomena in a map form. In addition to an examination of reconstructed maps of the world as conceived by Anaximander of Miletus, Hecataeus, Herodotus, Eratosthenes, and Ptolemy, this paper also assesses the writings of early Greek poets who tried to give a written picture of the known world of the time. This section will hopefully allow the reader to comprehend the stages through which the Greeks developed their geographical ideas and cartographic knowledge; from blurry and obscure notions of Mediterranean mariners -- as related by Homer -- to more scientific and mathematical approach of Claudius Ptolemy’s geography. In reviewing the literature of early geography and early conceptions of the earth, all sources lead to Homer , who is considered by many (Strabo, Kish and Dilke) as the founding father of Geography. Regardless of the doubts about Homer’s existence, one thing is certain he never was a mapmaker. The enclosed map (soon), which represents the conjectural view of the Homeric world was never created by him. It is an imaginary reconstruction of the world as Homer described it in his two poems the Iliad and the Odyssey. It is worth mentioning that each of these writings involves strong geographic symbolism. They can be seen as descriptive pictures of life and warfare in the Bronze Age and the illustrated plans of actual journeys. Thus, each one develops a philosophical view of the world, which makes it possible to show this information in the form of a map. Additional written statements about ancient geography can be found in Hesiod poems, written probably during the 7th century BCE The first steps in the development of scientific thought in ancient Greece belonged to Ionians from their well-known city of Miletus in Asia Minor. Miletus was favourably placed to absorb aspects of Babylonian science and culture and to profit from the expanding commerce of the Mediterranean. Thales of Miletus (c. 600 BCE) thought that the earth was a disk supported by water. Anaximander of Miletus (c. 611 – 546 BCE) was a pupil of Thales. It has been said that he believed that the earth was a cylindrical form [http://www.henry-davis.com/MAPS/Ancientimages/106A.GIF], like a stone pillar and suspended in space. The inhabited part of his world was a circular, disk-shaped, and presumably located on the upper surface of the cylinder. Anaximander was the first ancient Greek to draw a map of the known world. It is for this reason that he is considered by many to be the first mapmaker (Dilke). A scarcity of archaeological and written evidence prevents us from giving any assessment of his map. What we can assume is that he portrayed land and sea in a map form. Unfortunately, any definite geographical knowledge that he included in his map is lost. What is certain is that 50 years after Anaximander’s alleged map, Hecataeus of Miletus (550 – 475 BC) produced another map [http://sophistikatedkids.com/turkic/btn_GeographyMaps/World%20according%20to%20Hecataeus%20(6%20th%20century%20BC).gif] that he claimed was an improved version of the map of his illustrious predecessor. Another interesting figure in that era was Anaximenes of Miletus (6th century BCE), who studied under Anaximander. He rejected the views of his teacher regarding the shape of the earth and instead, he visualized the earth as a rectangular form supported by compressed air (Picture soon). What is interesting here is that his incorrect idea about the shape of the world somehow persisted in the form

Newlyn

External links

UÇK

External links

Conurbation

Examples

See also

External links

Civil parish

Geography

Parish councils

Powers and functions

Councillors and elections

Deserted parishes

Scotland, Wales and Ireland

History

See also

External links

Fishing

Fishing in antiquity

Origins

Ancient archaeology

Ancient representations

Ancient literature

Fishing techniques

Hand fishing

Spear and bow fishing

Fishing nets

Dredging

Fishing lines

Kite fishing

Ice fishing

Fish traps

Trained animals

Toxins

Explosives

Modern fishing

Recreational fishing

Commercial fishing

Preservation

Fish products

Food

Live fish

Other products

Cultural references

See also

External links

Further reading

Tides

Tidal terminology

Timing

Tidal physics

Tidal amplitude and cycle time

Tidal lag

Alternative explanation

Tides & fluids

Tides and navigation

Other tides

See also

External links

Ordnance Survey

Origins

The 20th century

UK Map Range

Cartography

OS MasterMap

See also

References

External links

Footnote

Cartography

History