DISTRIBUTION RISKS AND PROTECTION COUNTERMEASURES OF YANGTZE FINLESS PORPOISE IN POYANG LAKE DURING ABNORMAL DRY PERIOD

To study the risks of abnormal dry water levels in Poyang Lake to the survival of Yangtze finless porpoise (Neophocaena asiaeorientalis asiaeorientalis, YFPs), we conducted systematic surveys at high, low and extremely low water level in 2022. The results showed that, at high water level, YFPs exhibited a widespread distribution across the entire lake, predominantly congregating in the central expanse and showing lesser presence in the river channels and tributaries. At low water level, the distribution of YFPs became more localized and concentrated. They gradually entered the tributaries inlet channels and the northern channels of the main lake, displaying an increased affinity for sand pits and inlet channels. The distribution of YFPs were further concentrated during the period of extremely low water levels, showing accumulation toward the main trough, migration into the tributaries, and retention in the sand pits. Notably, the density of YFPs in the river channel reached its annual peak during this phase. The distribution of YFPs in Poyang Lake decreased sharply as the water level decreased, and YFPs is densely isolated in small water spaces. The investigation found that there are approximately 110 YFPs in the sand pit water area south of Piaotou in Songmen Mountain, approximately 18 YFPs downstream of the Xinjiang Ruihong Bridge, and about 20 YFPs in the Yangzizhou of the Ganjiang River. The YFPs is disturbed by human activities such as shipping and fishing, and also faces survival risks such as insufficient bait resources. This study not only presents the population abundance and distribution of YFPs in Poyang Lake across varying water levels in 2022 but also offers comparative insights into the distribution patterns of YFPs under abnormal climate scenarios. Additionally, it delves into their adaptive capacity and identify high-risk areas and risk factors. Combined with the series of rescue actions, the protection and rescue plan of YFPs in Poyang Lake during the period of abnormal water level was proposed. The results would propose new insights into the conservation of YFPs in Poyang Lake under abnormal water levels and provide scientific references for the conservation of YFPs under abnormal climate conditions in the middle and lower reaches of the Yangtze River.