Abstract: To investigate the characteristics of fish community structure in Qianxia Lake，a two‐year survey was conducted from 2022 to 2023，with sampling performed once in March，July，October，and December of each year，resulting in a total of eight sampling events. The results showed that a total of 40 fish species were collected and identified，belonging to 3 orders，9 families，and 31 genera.Among them，Cypriniformes accounted for the highest proportion（30 species，75%）.Ecological type analysis indicated that sedentary（92.50%），omnivorous（50%），and bottom‐dwelling fish（42.5%）were the main ecological groups.Community structure analysis identified six dominant species：Hemiculter leucisculus，Sinibrama macrops，Xenocypris microlepis，Coptodon zillii，Hypophthalmichthys nobilis and Culter alburnus.The results of Margalef species richness index and Shannon‐Wiener diversity index in biodiversity indexes showed that 2023 was higher than 2022.The results of catch per unit fishing effort showed that the average catch number per unit fishing effort and catch biomass per unit fishing effort in 2023 were higher than those in 2022，and the peak of catch number per unit fishing effort and catch biomass per unit fishing effort appeared in July 2023，with values of 8.32 ind（/m^²·d）and 1 131.88 g（/m^²·d），respectively.The abundance‐biomass comparison curve（W₂=0.037）indicated that the water body was in a moderately disturbed state.In summary，the construction of the Qianxia Lake Reservoir has changed the original fish resources situation. At the same time，the increase in the number of alien species and the risk of fish miniaturization may have a negative impact on the indigenous fish in the water area.

Key words: Fish, Qianxia Lake, Community structure, Biodiversity, Catch per unit fishing effort

摘要： 为探究千峡湖鱼类群落结构特征，于2022—2023年开展了为期2 a的调查，分别在每年3、7、10、12月各进行1次采样，共计8次。结果表明，调查共采集鉴定鱼类40种，隶属于3目9科31属，其中，鲤形目占比最高（30种，75%）。生态类型分析表明，定居型（92.50%）、杂食性（50%）和底层鱼类（42.5%）为主要生态类群。群落结构分析识别出6个优势种，分别为䱗、大眼华鳊、细鳞鲴、齐氏罗非鱼、鳙和翘嘴鲌。生物多样性指数中，Margalef物种丰富度指数和Shannon-Wiener多样性指数结果显示2023年高于2022年。单位捕捞努力量渔获量结果表明，2023年单位捕捞努力量渔获数量和单位捕捞努力量渔获生物量平均值均高于2022年，单位捕捞努力量渔获数量和单位捕捞努力量渔获生物量的峰值均出现在2023年7月，分别为8.32 ind（/ m^²·d）和1 131.88 g（/ m^²·d）。丰度-生物量比较曲线（W₂=0.037）表明水域处于中度扰动状态。综上，千峡湖水库的建设改变了原有的鱼类资源状况，同时外来物种数量的增加和鱼类小型化的风险可能给该水域的土著鱼类造成负面影响。

关键词: 鱼类, 千峡湖, 群落结构, 生物多样性, 单位捕捞努力量渔获量