葛洲坝至胭脂坝长江干流段江豚活动规律

长江江豚是我国一级保护野生动物,也是长江生态系统的指示性物种,其种群数量恢复情况及活动规律一直备受关注。本文选择长江宜昌段江豚活动频繁的葛洲坝下游至胭脂坝江段为研究区域,于2021年6月-2022年5月采用定点目测、水上流动监测与无人机监测相结合的方法分区监测长江江豚的游泳行为,分析长江江豚的活动规律,构建了长江江豚出水头次的零膨胀泊松回归模型,识别影响长江江豚出水头次的关键因素,建立长江江豚出水头次与各因素间的相关关系。结果表明:(1)葛洲坝至胭脂坝长江干流段监测到最大江豚出水头次为19头次,长江江豚集群规模以2~3头最为常见,占比达58.1%;长江江豚主要表现出4种行为特征,各行为占比从大到小依次为:玩耍＞休息＞摄食＞抚幼。(2)长江江豚在葛洲坝下游近坝区(A区,葛洲坝至至喜长江大桥)出水头次最多,且在秋冬季节累计出水头次多于春夏季节,冬季累计出水头次最高,达252头次。(3)长江江豚出水头次与电站下泄流量呈显著负相关;浊度增大,长江江豚出水的概率减小。本文研究结果对长江江豚生态保护策略及长江十年禁渔效果评估具有重要参考价值。

The activity rules of Yangtze finless porpoise(Neophocaena asiaeorientalis asiaeorientalis) in the main stream of the Yangtze River from Gezhouba Dam to Yanzhiba

The Yangtze finless porpoise (Neophocaena asiaeorientalis asiaeorientalis) is a first-class protected wild animal in China, and an indicative species of the Yangtze River ecosystem. Its population recovery and activity rules of Yangtze finless porpoises have received much attention. In this study, the section from Gezhouba Dam to Yanzhiba of the Yangtze River with high frequency of the Yangtze finless porpoises'' activities was selected as the study area. From June 2021 to May 2022, the movement of the Yangtze finless porpoise was monitored using the methods of fixed-point visual inspection, water flow and UAV monitoring. A Zero-inflated model Poisson regression model was developed to quantify the times of Yangtze finless porpoises exposed to the river surface. The environmental factors affecting the times of Yangtze finless porpoise exposed to the river surface were identified. Our investigation results indicated that: (1) The maximum times of Yangtze finless porpoises detected in the section from Gezhouba Dam to Yanzhiba was 19, with 2-3 of them being the most common in the Yangtze finless porpoise cluster size, accounting for 58.1%. The Yangtze finless porpoise had four major behavioral characteristics with an descending order of playing>resting>feeding>baby caring. (2) The Yangtze finless porpoise had the highest number of times in the downstream area of Gezhouba Dam (i.e., from Gezhouba Dam to Zhixi Yangtze Bridge), and had more individuals in autumn and winter than that in spring and summer. The cumulative number of individuals was highest (252) in winter. (3) The individuals of Yangtze finless porpoise had a significant negative correlation with the discharge of the power plant. With the increase of turbidity, the probability of Yangtze finless porpoise exposing to the river surface decreased. This study provided scientific support to design ecological protection strategies for the Yangtze finless porpoise, and to evaluate the ten-year fishing ban in the Yangtze River.