摘要
2007年4月18日～5月1日,利用SIMRAD EY60回声探测仪(又称鱼探仪)对三峡水库坝前到丰都干流以及9条主要支流进行了水声学探测。采用垂直探测结合"之"字形路线的方法对库区整个水体鱼类的分布状况进行了研究。调查水域长度约有600km,回波数据分成1232个片段进行分析。结果表明:在5m以下水层,体长大于6cm的鱼类在该区域平均密度为567.68尾/dam3,且鱼类分布不均匀。在巫山至奉节江段鱼类的密度最低,密度的平均值和标准误(mean±S.E)为(8.1±0.47)尾/dam3;在忠县到丰都江段密度最高,平均值和标准误(mean±S.E)为(2597.06±154.08)尾/dam3。从坝前到丰都,干流鱼类资源量总体上呈现逐步增加的趋势。支流资源量要比干流高。目标强度在-60～-50dB的鱼体大小差异不显著,大于-50dB鱼体的平均目标强度在巴东-巫山江段最高,巫山-奉节江段及抱龙河次之。小型鱼体的大小在各江段没有统计学差异,中型和大型鱼体在巴东-巫山江段鱼体个体相对最大,万州-忠县江段以及小江、长滩河等水域鱼类个体相对较小。
Hydroacoustic technology provides powerful tools for determining size, abundance, and distribution of fish. An application of a split - beam echosounder operating at 200 kHz was investigated to estimate the density of the fish stock in the Three Gorge reservoir in April and May 2007. The transducer was set vertically to get the fish echo from the depth of 5 meter to the bottom water layers. Survey has been conducted in the mainstream as well as in the nine anabranchs of the Three Gorges reservoir. All of the echogram has been divided into 1 232 units by 600 - 800pings per unit, each unit analysed indvidually. Results indicated that , on the area of surveyed, distribution of the fish stock is uneven and, the volume density of fish in the segment Wushan - Fengjie is rare, and the mean density merely is 8. lind./dam^3. （ SE = 0.47 ）, but in the segment Zhongxian - Fengdu is 2 597.06 ind./dam^3 （SE = 154.08） ,which is the highest volume density area of reservoir. The results also indicated that from Three Gorge Dam to segment Zhongxian - Fengdu, the volume density of fish stock has a trend of increasing. Meanwhile, volume density of fish stock in the anabranch is higher than that in the mainstream. The spatial variations of distribution of fish densities might caused by the ascending of water level or lower of the velocity of flow, Which need a future study.
出处
《水生态学杂志》
北大核心
2008年第5期25-33,共9页
Journal of Hydroecology
基金
中国长江三峡工程开发总公司生态与环境保护项目
国家自然科学基金重大项目(NSFC30490234)联合资助
关键词
三峡水库
水声学
目标强度
生物量
Three Gorges reservoir
Hydro - acoustic
Target - Strength
Biomass
