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A conventional idea of a sustainable fishery is that it is one that is harvested at a sustainable rate, where the fish population does not decline over time because of fishing practices. Sustainability in fisheries combines theoretical disciplines, such as the population dynamics of fisheries, with practical strategies, such as avoiding overfishing through techniques such as individual fishing quotas, curtailing destructive and illegal fishing practices by lobbying for appropriate law and policy, setting up protected areas, restoring collapsed fisheries, incorporating all externalities involved in harvesting marine ecosystems into fishery economics, educating stakeholders and the wider public, and developing independent certification programs. Some primary concerns around sustainability are that heavy fishing pressures, such as overexploitation and growth or recruitment overfishing, will result in the loss of significant potential yield; that stock structure will erode to the point where it loses diversity and resilience to environmental fluctuations; that ecosystems and their economic infrastructures will cycle between collapse and recovery; with each cycle less productive than its predecessor; and that changes will occur in the trophic balance (fishing down marine food webs).〔 Hilborn, Ray (2005) ("Are Sustainable Fisheries Achievable?" ) Chapter 15, pp. 247–259, in Norse and Crowder (2005).〕 ==Overview== Global wild fisheries are believed to have peaked and begun a decline, with valuable habitats, such as estuaries and coral reefs, in critical condition.〔Tietenberg TH (2006) ''Environmental and Natural Resource Economics: A Contemporary Approach''. Page 28. Pearson/Addison Wesley. ISBN 978-0-321-30504-6〕 Current aquaculture or farming of piscivorous fish, such as salmon, does not solve the problem because farmed piscivores are fed products from wild fish, such as forage fish. Salmon farming also has major negative impacts on wild salmon.〔Knapp G, Roheim CA and Anderson JL (2007) (''The Great Salmon Run: Competition Between Wild And Farmed Salmon'' ) World Wildlife Fund. ISBN 0-89164-175-0〕〔Washington Post. (Salmon Farming May Doom Wild Populations, Study Says ).〕 Fish that occupy the higher trophic levels are less efficient sources of food energy. Fishery ecosystems are an important subset of the wider marine environment. This article documents the views of fisheries scientists and marine conservationists about innovative approaches towards sustainable fisheries. 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「Sustainable fishery」の詳細全文を読む スポンサード リンク
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