基于水声学探测的香溪河鱼类资源时空分布特征评估

为了掌握三峡水库香溪河鱼类资源时空分布特征, 2013 年5 月和11 月运用Simrad EY60 型分裂波束回声探测仪在香溪河进行了水声学探测, 辅以常规渔获物分析方法。渔获物调查共发现鱼类7 科41 种, 其中似鳊、贝氏、、银和蛇等小型鱼类在数量上占据优势地位。水声学探测结果表明, 香溪河春季鱼类密度显著高于秋季, 采用加权平均法求得2013 年5 月和11 月探测的鱼类密度分别为53.4 和15.4 ind./1000 m3。鱼类资源在空间上不均匀分布, 从高岚河至香溪河口鱼类密度逐渐降低;在垂直方向上, 春季和秋季水声学探测的鱼类密度显示出相同的趋势, 即表层 中层 底层。在运用鱼类生物操纵改善水质途径方面, 建议通过壮大肉食性鱼类种群来控制小型鱼类资源量, 同时通过增殖放流鲢、鳙以加强对浮游植物的滤食作用。  

HYDROACOUSTIC ASSESSMENT OF SPATIO-TEMPORAL DISTRIBUTION AND ABUNDANCE OF FISH RESOURCES IN THE XIANGXI RIVER

In order to better understand the spatial-temporal distribution and the biomass of fish in the Xiangxi River, we applied hydroacoustic analysis with Simrad EY60 split-beam echo sounder and investigated the fish grounds in the Xiangxi River in May and November of 2013. We found 41 fish species in the survey, and the dominant species included Pseudobrama simoni, Hemiculter bleekeri, Hemiculter leucisculus, Squalidus argentatus, and Saurogobio dabryi. The fish density was higher in spring than autume, with the typical values of 53.4 ind./1000 m3 in May and 15.4 ind./1000 m3 in November. The spatial distribution of fish in the Xiangxi River showed an uneven pattern. Horizontally the fish density decreased from the Gaolan River to the estuary of the Xiangxi River. Vertically the fish abundance followed the order: the surface layer the middle layer the bottom layer, and the distribution was the same in both spring and autumn. Here we suggested two biomanipulation methods to improve the water quality in the Xiangxi River: (1) to suppress the small fishes by increasing the population of piscivorous fishes, (2) to suppress the phytoplankton by raising planktivorous silver carp and bighead carp.