禁捕首年长江安庆段仔稚鱼群聚特征

THE COMMUNITY CHARACTERISTICS OF LARVAL AND JUVENILE FISH IN ANQING SECTION OF THE YANGTZE RIVER DURING THE FIRST YEAR OF FISHING BAN

  • 摘要: 为掌握禁捕首年长江安庆段仔稚鱼群落特征及其变化, 于2021年4月18日至8月14日开展长江安庆段仔稚鱼逐日采样调查。结果显示: 调查共采集鉴定仔稚鱼338922尾, 鉴定出鱼类39种, 隶属于6目9科31属, 鲤科鱼类的物种数和数量占据优势, 占比分别为79.48%和96.59%。在生态类型上, 淡水定居性鱼类占绝对优势, 数量和物种数占比分别为92.27%和48.71%。在产卵类型上, 产漂流性卵鱼类占绝对优势, 物种数和数量占比分别为46.15%和92.27%。在群落结构上, 贝氏䱗(Hemiculter bleekeri)为第一优势种, 数量占比44.53%, 䱗(Hemiculter leucisculus)和银鲴(Xenocypris argentea)为主要优势种。在资源丰度时间分布上, 5—7月仔稚鱼丰度最高, 均值为1093 ind./100 m3, 峰值出现在7月6日, 为4097 ind./100 m3。同往年的调查结果相比, 物种数方面, 2016—2020年的物种数变幅为37至49种, 2021年为39种; 仔稚鱼丰度方面, 2016—2020年的平均丰度变幅为355—1185 ind./100 m3, 2021年为916 ind./100 m3; 2016—2020年的丰度峰值变幅为823—8081 ind./100 m3, 2021年为4097 ind./100 m3。冗余分析(RDA)表明, 仔稚鱼丰度与调查期间的流量、水位、水温和浊度呈正相关(P<0.05)。研究探明了禁捕初期长江安庆段仔稚鱼的资源现状, 相关研究结果可为长江十年禁渔效果评估过程分析提供数据支撑。

     

    Abstract: Anqing section is located in the lower reaches of the Yangtze River, which is one of the important fish habitats. In order to understand the community characteristics of larval and juvenile fish and the interannual variation from 2016 to 2021, the daily survey was conducted from the 18 April to the 14 August, 2021. A total of 338922 juvenile fishes were collected and identified, belonging to 31 genera, 9 families and 6 orders. The dominant fish species and quantity of Cyprinidae accounting for 79.48% and 96.59%, respectively. In terms of ecological types, freshwater resident fishes were the absolute dominant in terms of number (95.13%) and species (79.49%). Drifting ovo-producing fishes were the absolute dominant in terms of spawning types, accounting for 92.27% and 48.71%, respectively. Hemiculter bleekeri was the first dominant species, accounted for 44.53%, followed by Hemiculter leucisculus and Xenocypris argentea. The highest abundance of larval and juvenile fish from May to July, with an average of 1093 ind./100 m3, and the peak abundance was observed on the 6 July, reaching 4097 ind./100 m3. Compared with the survey results from previous years, the number of species ranged from 37 to 48 from 2016 to 2020, and 39 in 2021. The average abundance of young and juvenile fish ranged from 355 to 1185 ind./100 m3 from 2016 to 2020, and 916 ind./100 m3 in 2021. The peak abundance ranged from 823 to 4920 ind./100 m3 from 2016 to 2020 and 8081 ind./100 m3 in 2021. Redundancy analysis (RDA) indicated a positive correlation between the abundance of larval and juvenile fish and water flow, water level, turbidity and water temperature. This study investigated the resource status of larval and juvenile fish in Anqing section of Yangtze River in the early period of the fishing ban, enriched the basic data of early fish resources in the Yangtze River trunk stream, and provided support for the evaluation on the effect of the fishing ban.

     

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