Chinese Sturgeon (Acipenser sinensis) in the Yangtze River: a hydroacoustic assessment of fish location and abundance on the last spawning ground

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	Chinese Sturgeon (Acipenser sinensis) in the Yangtze River: a hydroacoustic assessment of fish location and abundance on the last spawning ground
	Qiao, Y. ; Tang, X. ; Brosse, S. ; Chang, J.
	2006
会议名称	5th International Symposium on Sturgeons
会议日期	MAY 09-SEP 13, 2005
会议地点	Ramsar, IRAN
关键词	FISHERIES ACOUSTICS
页码	140-144
通讯作者	Chang, J, Minist Water Resources & Chinese Acad Sci, Inst Hydroecol, 578 Xiongchu Ave, Wuhan 430079, Peoples R China
中文摘要	Chinese sturgeon ( Acipenser sinensis), was once widely dispersed in almost all watersheds draining towards the western coasts of the Pacific Ocean. Today, the species is one of the highly endangered fish species in China and can be found only in the Yangtze and Pearl rivers and their adjacent coastal and marine areas. Due to the construction of the Gezhouba Dam, spawning grounds for the fish were drastically restricted but fortunately remained in the Yangtze River at a small-scale site located just downstream along a short reach of the river closely to the dam. Since 1998 we have undertaken annual investigations in this area using hydroacoustic methods, in order to estimate the size of spawning cohort and the selection of habitats. Based on strength and sizes of echo signals, the mature individuals of Chinese sturgeon were discriminated from the other fish species and then numerated. Most of the fish were detected close to the bottom and preferred to distribute themselves in the areas with water depths less than 15 meters. Because of different bottom structures with homogeneous granular material, the distribution of the fish was mainly influenced by water depths and perhaps current patterns. Total amount of sturgeons in the entire reach were estimated by simply summing up the numbers according to the identified densities in areas of different depths. Usually, there were about two separate spawning activities of Chinese sturgeon which took place annually during the observation period, with the scale of spawning activity being much larger at the first time than during the following spawning events. Estimations on the sizes of spawning cohorts on the restricted spawning ground before the first wave of upstream migrants appeared, were about 400 and 200 individuals during the periods of 1998-1999 and 2002, respectively. It was demonstrated that: a) the space of the current spawning site is not sufficient to accommodate all mature individuals simultaneously, and b) a serious decline in spawning stocks size of Chinese sturgeon during the investigational period seems to be indicated when comparing the counts between 1998 and 2002. The decline is about 50% which is a highly alarming figure.
收录类别	SCI
会议主办者	Iranian Fisheries Res Org, Int Sturgeon Res Inst, World Sturgeon Conservat Soc, IUCN/SSC Sturgeon Specialist Grp, CITES, Minist Jihad Agr Iran, Iranian Fisheries Org, Shilat Trading Co, Imperial Caviar
会议录	JOURNAL OF APPLIED ICHTHYOLOGY
语种	英语
WOS记录号	WOS:000247966100023
内容类型	会议论文
源URL	[http://ir.ihb.ac.cn/handle/342005/11769]
专题	水生生物研究所_中科院水生所知识产出（2009年前）_会议论文
推荐引用方式 GB/T 7714	Qiao, Y.,Tang, X.,Brosse, S.,et al. Chinese Sturgeon (Acipenser sinensis) in the Yangtze River: a hydroacoustic assessment of fish location and abundance on the last spawning ground[C]. 见:5th International Symposium on Sturgeons. Ramsar, IRAN. MAY 09-SEP 13, 2005.