| 摘要: |
| 长江口江苏段为江阴大桥至长江口北支入海口，受海洋潮汐影响较大，是长江江豚（Neophocaena asiaeorientalis）最下游分布区。为掌握该区域长江江豚种群数量和分布状况，于2023年进行了4次船只目视调查，并于2019年12月—2023年12月采用定点观测、环境DNA（eDNA）监测等方法进行监测。结果显示，2019年12月—2023年12月，累计观测到长江江豚236次，718头次。江阴大桥至崇启大桥，两岸均有长江江豚分布，热点区域为五山江段、常阴沙江段和江阴大桥江段。4次船只目视调查（样线1 274 km）共目击到长江江豚28次，计65头次。长江江豚的遇见率为0.02~0.13头次/km，平均遇见率为0.05头次/km。可见系数法估算结果得到2，5，9，11月该江段种群数量为14.8~64.8头，平均为38.9头。长江江豚冬、春季较为活跃。长江江豚热点区域自然岸线相对较多，人为活动干扰较小。针对长江口江苏段无专门长江江豚保护地，缺乏系统监测与保护措施等问题，提出应完善监测体系、加大保护力度、将长江江豚热点活动区域作为重点监护区以及建立长江江豚自然保护区等建议。 |
| 关键词: 长江江豚 长江口 目视调查 种群监测 |
| DOI：DOI：10.3969/j.issn.1674-6732.2024.03.004 |
| 分类号:S917.4 |
| 基金项目:江苏省环境监测科研基金项目（2218，2117，2312）；南通市市级科技计划指令性项目 （ JC2020164） |
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| Population Monitoring of Yangtze River Finless Porpoises in the Jiangsu Section of the Yangtze River Estuary |
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XIN Yu， ZHANG Zaifeng， YU Xiangxiang*， TANG Chunyan， ZHOU Yuxiang， CHEN Gong， HU Xiaofeng
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Nantong Environmental Monitoring Centre of Jiangsu Province， Nantong， Jiangsu 226006， China
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| Abstract: |
| The Jiangsu section of the Yangtze River Estuary spans from the Jiangyin Bridge to the mouth of the northern branch of the Yangtze River Estuary， and is heavily influenced by ocean tides， representing the downstream distribution area of the Yangtze River Finless Porpoises（Neophocaena asiaeorientalis）. To elucidate the population and the distribution status of the Yangtze River finless porpoises in this region， four visual surveys were conducted on ships in 2023， complemented by applying methods such as fixed point observation and eDNA monitoring. Based on the observation data from December 2019 to December 2023， a total of 236 observations and 718 sightings of Yangtze River finless porpoises were recorded. From Jiangyin Bridge to Chongqi Bridge， Yangtze River finless porpoises were observed on both sides， with hot spots regions identified in the Wushan River section， Changyin Shanjiang section， and Jiangyin Bridge section.The result revealed a total of 28 groups of Yangtze River finless porpoises observed during the four visual surveys（covering a sample line of 1 274 kilometers）， totaling 65 sightings. The encounter rate of Yangtze River Finless porpoises ranged from 0.02 to 0.13 times/km， with an average encounter from 0.05 times/km. Acording to the visible coefficient method， the estimated population size in February， May， September and November for this river section ranged from 14.8 to 64.8， with an average of 38.9 individuals. Yangtze River finless porpoises can be observed throughout the year， being more active in winter and spring. The hot spot regions for Yangtze River finless porpoises feature more natural shorelines and less human interference. In view of the lack of special Yangtze finless porpoise protection area and systematic monitoring and protection measures in the Jiangsu section of the Yangtze River Estuary， suggestions were put forward to improve the monitoring system， increase protection efforts， take the Yangtze finless porpoise hot spot activity area as a key monitoring area and even establish the Yangtze finless porpoise nature reserve. |
| Key words: Yangtze River finless porpoises（Neophocaena asiaeorientalis） Yangtze River estuary Visual investigation Population monitoring |
