长江上游保护区重庆段鱼类重要栖息地水环境及鱼类分布特征研究

为探究长江上游珍稀特有鱼类国家级自然保护区(以下简称“保护区”)重庆段鱼类重要栖息地(产卵场、索饵场和越冬场)的水环境及鱼类分布特征,本研究分别于2021年冬季(越冬期)、2022年夏季(产卵期)、2022年秋季(索饵期)在保护区重庆段设置羊石(S₁)、松溉(S₂)、白沙(S₃)、油溪-龙华(S₄)、江津城区(S₅)、珞璜(S₆)等6个调查江段,开展3次水声学调查并分析各江段的水质状况。水声学调查结果表明,3次探测鱼类的平均密度相差不大,分别为0.584、0.590、0.595 ind./m²,所探测的重要栖息地以古家沱、丁家沱、江口、王家沱等产卵场鱼类分布较多。鱼类密度在不同江段存在显著性差异(P＜0.05),整体表现为下游高于上游;重要栖息地鱼类密度在不同江段存在显著性差异(P＜0.05),而在不同时期差异不显著(P>0.05),且整体明显大于非重要栖息地。水质监测结果表明,上、下游水质差异不明显,7个水质指标中除总氮外其余指标均达到Ⅲ类地表水标准,符合渔业水质要求。综上,保护区重庆段鱼类重要栖息地水质状况良好,能满足鱼类生长繁殖的需要。

Study on the Water Environment and Fish Distribution Characteristics of Fish Important Habitat in Chongqing Section of the Upper Reaches of Yangtze River Reserve

In order to explore the water environment and fish distribution characteristics of important habitats (spawning grounds,feeding grounds,and wintering grounds) in Chongqing Section of the Upper Reaches of the Yangtze River Reserve (hereinafter referred to as the “Reserve”),in winter 2021 (Overwintering period),summer 2022(Oviposition period) and autumn 2022(Baiting period),six survey river sections were set up in the Chongqing section of the reserve,including Yangshi (S₁),Songgai (S₂),Baisha (S₃),Youxi-Longhua (S₄),Jiangjin urban area (S₅),Luohuang(S₆).Three hydroacoustic surveys were carried out and the water quality of each river section was analyzed.The results of hydroacoustic survey showed that the average densities of fish in the three times were 0.584,0.590 and 0.595 ind./m²,respectively.The important habitats detected were mainly distributed in spawning grounds such as Gujiatuo,Dingjiatuo,Jiangkou and Wangjiatuo.There were significant differences in fish density in different river sections (P<0.05),and the overall performance was higher in the downstream than that in the upstream.The density of fish in important habitats was significantly different in different river sections (P<0.05),but not significantly different in different periods (P>0.05),and the overall density was significantly higher than that in non-important habitats.The results of water quality monitoring showed that there was no obvious difference in water quality between upstream and downstream.In summary,the water quality of important habitats in the Chongqing section of the protected area is good,which can meet the needs of fish growth and reproduction.Except total nitrogen,the other seven water quality indexes all reached the class Ⅲ surface water standard,which met the requirements of fishery water quality.In summary,the water quality of the important habitats for fish in the Chongqing section of the reserve is good,which can meet the needs of fish growth and reproduction.