重庆新白沙沱长江特大桥施工江段鱼类时空分布特征研究

Study on Spatial and Temporal Distribution of Fish in the Construction Section of the New Baishaotuo Yangtze River Super-long Bridge

【目的】了解重庆新白沙沱长江特大桥施工江段鱼类的时空分布特征及对该特征可能有影响的环境因子。【方法】于2015年12月22日和2016年3月29日、8月3日、11月2日在大桥上下游江段使用Simrad EY60回声探测仪对渔业资源进行水声学调查。【结果】4次调查结果显示:大桥上游江段的鱼类平均密度分别为5.8×10^(-3),9.1×10^(-3),24.6×10^(-3)和8.4×10^(-3)个·m^(-3),大桥下游江段的鱼类平均密度分别为7.4×10^(-3),15.3×10^(-3),39.4×10^(-3)和20.6×10^(-3)个·m^(-3);2016年8月3日在大桥下游江段探测到的鱼类密度大于其他3次调查在同一江段探测到的鱼类密度,差异具有统计学意义(p<0.05)。【结论】新白沙沱长江特大桥上下游江段鱼类密度分布不均,下游的鱼类密度比上游的大,夏季的鱼类密度比冬、春季的大;鱼类密度的空间差异性和季节差异性可能与鱼类生命活动的季节变化、当地的河流环境差异相关,也可能与桥梁的施工影响相关。

[Purposes]In order to determine the spatial and temporal distribution characteristics of fish in the river that is carrying out the new Baishaotuo Yangtze river bridge construction as well as which environmental factor may be affected.[Methods]On December22,2015,March 29,August 3,and November 2,2016,SIMRAD EY60 echo sounder was used to carry out underwater acoustic survey for fishery resources in the upper and lower reaches of Yangtze River.[Findings]The average densities in the upper stream of the four surveys are respectively 5.8×10^（-3）,9.1×10^（-3）,24.6×10^（-3）,and 8.4×10^（-3） ind.·m^（-3）;the average densities in the lower stream of the four surveys are respectively 7.4×10^（-3）,15.3×10^（-3）,39.4×10^（-3）,and 20.6×10^（-3） ind.·m^（-3）.The results show that the fish density detected in the lower reaches of the bridge on August 3,2016 was statistical significant larger compared with the fish density detected in the other three times（p〈0.05）.[Conclusions]The bridge on the downstream of fish density distribution is uneven,the downstream than upstream,in summer than in winter and spring.The spatial differences and seasonal variations of fish density may be related to the seasonal changes of fish life,and are related to the difference of river environment in the region,and may also be related to the construction effects of bridges.