Temporal and spatial biosonar activity of the recently established uppermost Yangtze finless porpoise population downstream of the Gezhouba Dam: Correlation with hydropower cascade development, shipping, hydrological regime, and light intensity
葛洲壩下游最近建立的長江江豚種群的時空生物聲納活動：與水電梯級開發、航運、水文狀況和光照強度的相關性
Abstract
Numerous dams disrupt freshwater animals. The uppermost population of the criticallyendangered Yangtze finless porpoise has been newly formed below the Gezhouba Dam, however, information regarding the local porpoise is scarce. Passive acoustic monitoring was used to detect the behaviors of porpoises below the Gezhouba Dam.The influence of shipping, hydrological regime, and light inten sity on the biosonar activity of dolphins was also examined using Generalized lin ear models. Over the course of 4?years (2019–2022), approximately 848, 596, and 676 effective monitoring days were investigated at the three sites, from upstreamto downstream. Observations revealed significant spatio-temporal biosonar activity.Proportion of days that are porpoise positive were 73%, 54%, and 61%, while por poise buzz signals accounted for 78.49%, 62.35%, and 81.30% of all porpoise biosonarat the three stations. The biosonar activity of porpoises was much higher at the con fluence area, particularly at the MZ site, during the absence of boat traffic, and during the Pandemic shutdown. Temporal trends of monthly, seasonal, and yearly variation were also visible, with the highest number of porpoises biosonar detected in the sum mer season and in 2020. Significant correlations also exist between the hydrological regime and light intensity and porpoise activity, with much higher detections during nighttime and full moon periods. Hydropower cascade development, establishment of a natural reserve, fish release initiatives, and implementation of fishing restric tions may facilitate the proliferation of the porpoise population downstream of the Gezhouba Dam within the Yichang section of the Yangtze River. Prioritizing restora tion designs that match natural flow regimes, optimize boat traffic, and reduce noise
pollution is crucial for promoting the conservation of the local porpoises.
摘要
許多水壩破壞了淡水動物。最重要的群體瀕臨滅絕的長江江豚在葛洲壩下新形成然而，大壩關于當地海豚的信息很少。被動聲監測用于檢測葛洲壩下江豚的行為。還使用廣義線性模型研究了航運、水文狀況和光照強度對海豚生物聲納活動的影響。在4的過程中?年份（2019年至2022年），約848年、596年和在上游的三個地點調查了676個有效監測日到下游。觀測揭示了顯著的時空生物聲納活動。海豚陽性的天數比例分別為73%、54%和61%，而海豚嗡嗡聲信號分別占所有海豚生物聲納的78.49%、62.35%和81.30%在三個車站。在沒有船只通行的情況下，在影響區，特別是在MZ現場，鼠海豚的生物聲納活動要高得多疫。月度、季度和年度變化的時間趨勢在夏季和2020年檢測到的海豚數量最多。水文要素之間也存在顯著相關性環境、光照強度和海豚活動，在夜間和滿月期間。水電梯級開發、建設自然保護區、魚類放流倡議和捕魚限制的實施可能會促進江豚種群在下游的擴散葛洲壩位于長江宜昌段。優先考慮符合自然流態、優化船舶交通和降低噪音的修復設計污染對于促進當地鼠海豚的保護至關重要。
