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Dabry's sturgeon (''Acipenser dabryanus'') is a species of fish in the sturgeon family, Acipenseridae. Other common names include Yangtze sturgeon, Chiangjiang sturgeon, and river sturgeon.〔Zhuang, P., et al. (1997). (Biology and life history of Dabry's sturgeon, ''Acipenser dabryanus'', in the Yangtze River. ) ''Environmental Biology of Fishes'' 48(1-4), 257-64.〕 It is endemic to the Yangtze River Basin in China. It was a food fish of commercial importance. Its populations declined drastically, and in the early 1980s, it was designated an endangered species and commercial harvest was banned.〔 It has been listed as a critically endangered species by the IUCN since 1996 and since 2010 (possibly extinct) has been added to its status.〔 This sturgeon has been known to reach 2.5 m in length, but it is usually much smaller.〔Froese, R. and D. Pauly. (Eds.) (''Acipenser dabryanus''. ) FishBase. 2011.〕 Its body is blue-gray above and yellowish white on the belly, with five rows of scutes. The head is triangular and the snout is long with the mouth located on the underside. There are two pairs of barbels.〔Gao, X., et al. (2009). (Threatened fishes of the world: ''Acipenser dabryanus'' Duméril, 1869. ) ''Environmental Biology of Fishes'' 85(2), 117-18.〕 The fish lives in slow-moving river waters over substrates of sand and mud. It feeds on aquatic plants, invertebrates, and small fish. This species is potamodromous, taking part in a migration, but never leaving fresh water.〔 It spawns in the upper Yangtze, mainly during March and April, and sometimes around November and December. Males spawn each year, but most females do not. The female produces 57,000 to 102,000 eggs.〔 This was once a common fish in the Yangtze system.〔 It was known from the main river and some of its larger tributaries, as well as some lakes attached to the system. By the late 20th century, it was extirpated from the lower river and limited to the upper reaches in Sichuan. The main causes of its drastic decline include overfishing, including the overharvesting of juveniles. The construction of dams, such as the Three Gorges Dam, blocked the movement of the fish along the river, restricting it to the upper reaches. It also caused habitat fragmentation and degradation. Increased development and deforestation on land near the river has increased pollution from wastewater and runoff.〔 The fish has been bred in captivity since the 1970s. Thousands of individuals have been released into the river, but are apparently not breeding. Nevertheless, this restocking may be the only effort preventing the extinction of the species.〔 ==See also== * List of endangered and protected species of China 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「Dabry's sturgeon」の詳細全文を読む スポンサード リンク
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