三峡库区鱼类时空分布特征及与相关因子关系分析

【作者】 王珂；

【导师】 廖文根； 李翀；

【作者基本信息】 中国水利水电科学研究院 ， 水环境学， 2013， 博士

【摘要】 三峡库区地理位置和自然条件独特,鱼类资源丰富,是许多珍稀鱼类栖息、索饵和繁殖的最佳场所,在物种多样性、代表性和特殊性方面有重要的科学价值和生态、社会、经济价值,三峡库区渔业资源的保护和利用己成为社会公众关注的热点之一由于三峡工程巨大的调蓄作用,导致库区生态环境发生改变,鱼类分布格局也将发生变化。对三峡水库不同蓄水位下鱼类资源及其分布特征进行研究,并分析分布特点和相关环境、水文因子的关系,对三峡库区渔业资源的利用和保护具有重要意义。本文以三峡库区秭归至重庆江段为研究对象,通过水声学监测的方法,对三峡库区鱼类的时空分布特征进行研究。在三峡库区的巫山、万州、忠县和长寿江段分别设站点,进行渔获物调查,对水声学监测数据进行了对比分析。在水声学监测的同时,对各江段的环境因子进行了测定,分析了各环境因子和鱼类密度之间的相关性。采用MIKE11水动力学模型,对三峡库区在调查期间的水深、流速、流量等因素进行了模拟,并分析了这些因素对鱼类密度分布的影响。本文主要研究结论如下：1)三峡库区干流鱼类密度变化特点如下：时间上,同一季节比较,三峡库区干流鱼类密度呈逐年增加的趋势,并且,冬季的鱼类密度平均值大于同年春季鱼类密度的平均值。空间上,水平方向表现为从下游到上游越来越大；冬季,鱼类密度最大值位于忠县附近,2009年冬季鱼类聚集于丰都上游江段,而在春季,鱼类喜居于上游的长寿至重庆江段。垂直方向,不同江段的特征不一。支流(库湾)鱼类密度变化特点为：时间上,各支流冬季鱼类密度均大于春季的鱼类密度,并且冬季支流鱼类密度的平均值明显大于干流鱼类密度的平均值,而春季则相反；空间上,冬季鱼类密度最大的支流为大宁河,春季则为梅溪河、朱衣河和磨刀溪。2)2006-2010年间,分别在三峡库区的库首、库中和库尾选择了巫山、万州、忠县和长寿江段进行渔获物调查,结果发现：不同江段的渔获物优势种不同,共有鲢、南方鲶、鲫、鲤、铜鱼、长鳍吻鮈和圆口铜鱼7种,并且渔获物优势种的生活习性和三峡库区水声学监测获得的鱼类分布特征相吻合。此外,监测期间,万州江段渔获物总量和日均单船产量基本都呈逐年增加的趋势,和水声学监测结果呼应。3)测定水质因子包括水温、溶解氧、电导率、电阻、盐度、总溶解性固体和pH。其中,水温对春季鱼类密度分布有显著影响,而各水质因子和冬季鱼类的分布无相关性。其中,春季水温从库首到库尾逐渐增加的特点,是造成库尾江段春季鱼类密度最大的一个重要因素；所测定的环境因子都不是冬季三峡库区鱼类分布特征的限制因子。4)模拟的各水文因子,包括水深、流量、流速、过水面积和水面宽。通过对各因子和相应江段的鱼类密度相关性分析发现,流速、水深和过水面积和春季鱼类密度的相关性极显著,水面宽和冬季鱼类的密度分布显著相关。春季鱼类繁殖对水流流速的要求,是造成库尾江段春季鱼类密度最大的又一个重要因素；而模拟的各水文因子都不是造成冬季鱼类聚集忠县及丰都江段的原因。5)综合分析表明,三峡库区鱼类资源量的增加趋势以及分布特征是水温、水流流速、水深、流态、鱼类生活习性、营养物质和保护政策共同作用的结果。更多还原

【Abstract】 The Three Gorges Reservoir is the best habitat, foraging and spawning grounds for many rare, unique and economic fishes, fishery resource in which is very ample. Hence, the scientific, ecological, social and economic value of the reservoir is important and the protection and utilization of fishery resource in the Three Gorges Reservoir is a hot point.The ecology environment of the Three Gorges Reservoir was inevitably changed as the huge storage and discharge. Therefore, the distribution of fish in the reservoir would change correspondingly. To study the fishery resource and its distribution characteristic under different water level and analysis the relationship between fish density and relative environmental and hydrologic factors is significant to fish protection and utilization of the Three Gorges Reservoir.In this study, the studied area was from Zigui to Chongqing. First, we detected the fish distribution in this area using hydroacoustic equipment. Second, we investigated fish catch at Wushan, Wanzhou, Zhongxian and Changshou sections and compared the fish catch data with the hydroacoustic data. Third, we monitored some environmental factors and analysis the dependency of these factors and fish density. Finally, we imitated the water depth, water velocity and water volume of the Three Gorges Reservoir using the model MIKE11and analysis the influence of these factors to the fish distribution.The conclusions are as following.The fish density in the main stream of the Three Gorges Reservoir was increasing year by year when we compared the data in same season and the fish density in winter was always higher than the value in spring of the same year. Furthermore, the fish density in the upper reach was almost higher than that in the lower reach of the reservoir. In winter, fishes like to live at the section around Zhongxian and in spring, fishes apt to live at the section from Changshou to Chongqing. To the branches of the reservoir, we found the fish density of every branch in winter was almost higher than that in spring and also higher than that in the main stream. In winter, the highest fish density was detected in the Daning River and in spring, the highest density was found in the Meixi River, Zhuyi River and Modao River.Fish catch investigations were conducted in Wushan, Wanzhou, Zhongxian and Changshou section from2006to2010, the results showed that different section had different dominant species and silver carp, southern catfish, crucian, common carp, copper fish, rhinogobio ventralis and coreius guichenoti were dominant species of the whole reservoir. The habits of the dominant species were coincided with the fish distribution characteristics in the hydroacoustic detection. The fish catch and average daily output at the Wanzhou section were increasing year by year, which was similar to the hydroacoustic data.The detected environmental factors included water temperature, dissolved oxygen, salinity, conductivity, resistance, total dissolved solid and pH. During the seven factors, water temperature was significant correlated with the fish distribution in spring, but all of the environmental factors has no correlation with the fish distribution in winter. In spring, the water temperature was increasing from lower to upper reach of the reservoir which resulted in the fish density in the upper reach was the highest. In winter, the tested environmental factors were not limiting factor for fish distribution in the Three Gorges Reservoir.The imitated hydrologic factors included water depth, discharge, water velocity, flow area and flow width. The relationship between hydrologic factors and fish density of different section was analyzed, the results showed that water velocity, water depth and flow area were highly siginificant correlated with fish density in spring and flow width was significant correlated with fish density in winter. The demand of water velocity was another important reason for fish distribution in spring. In winter, the imitated hydrologic factors were not limiting factor for fish distribution.Finally, we summaried the reasons for fish amount increasing and distribution characteristics in the Three Gorges Reservoir and considered water temperature, water velocity, water depth, flow state, living habit of fish and protection policy were the main factors.更多还原