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A fish trap is a trap used for fishing. Fish traps may have the form of a fishing weir or a lobster trap. A typical trap might consist of a frame of thick steel wire in the shape of a heart, with chicken wire stretched around it. The mesh wraps around the frame and then tapers into the inside of the trap. When a fish swims inside through this opening, it cannot get out, as the chicken wire opening bends back into its original narrowness. In earlier times, traps were constructed of wood and fibre. ==History== 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 bottle or pot traps that are usually, but not always baited to attract prey, and are periodically lifted out of the water. The Mediterranean Sea, with an area of about of 2.5 million km2 (970,000 sq mi), is shaped according to the principle of a bottle trap. It is easy for fish from the Atlantic ocean to swim into the Mediterranean through the narrow neck at Gibraltar, and difficult for them to find their way out. It has been described as "the largest fish trap in the world".〔Bhuyan, Vishaal B (2011) (''The Esoteric Investor: Alternative Investments for Global Macro Investors'' ) FT Press. ISBN 9780132485074.〕 The prehistoric Yaghan people who inhabited the Tierra Del Fuego area constructed stonework in shallow inlets that would effectively confine fish at low tide levels. Some of this extant stonework survives at Bahia Wulaia at the Bahia Wulaia Dome Middens archaeological site.〔C. Michael Hogan (2008) (''Bahia Wulaia Dome Middens'', Megalithic Portal'', ed. Andy Burnham )〕 In southern Italy, during the 17th century, a new fishing technique began to be used. The trabucco is an old fishing machine typical of the coast of Gargano protected as historical monuments by the homonym National Park. This giant trap, built in structural wood, is spread along the coast of southern Adriatic especially in the province of Foggia, in some areas of the Abruzzese coastlines and also in some parts of the coast of southern Tyrrhenian Sea. 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.〔Jared Diamond: ''Guns, Germs, and Steel: The Fates of Human Societies''. page 310. W.W. Norton & Company, March 1997. ISBN 0-393-03891-2.〕 Most have been completely or partially destroyed. The largest and best-known are those on the Barwon River at Brewarrina, New South Wales, which are at least partly preserved.〔(Brewarrina Aboriginal Fish Traps ).〕 The Brewarrina 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 system of canals, some more than 2 km long. The purpose of these canals was to attract and catch 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.〔(Ajumawi Fish Traps ).〕 A technique called dam fishing is used by the Baka pygmies. This involves the construction of a temporary dam resulting in a drop in the water levels downstream— allowing fish to be easily collected.〔(Dam Fishing ) Fishing techniques of the Baka.〕 Also used in Chile, mainly in Chiloé, which were unusually abundant (fish weir and basket fish trap). 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「fish trap」の詳細全文を読む スポンサード リンク
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