Disribution Patterns of Yangtze Finless Porpoise in Yangtze River and its Correlation to Hydrological Characteristics
Yangtze finless porpoise ( Neophocaena phocaenoides asiaeorientalis) is the only freshwater subspecies of finless porpoise ( Neophocaena phocaenoides) , as well as the only freshwater population of six extant porpoise ( Phocoenidae). This subspecies exclusively inhabits in the middle and lower reaches of the Yangtze River and two appended lakes (Poyang and Dongting) in China. A survey conducted in 2006 by an international team suggests that the abundance of Yangtze finless porpoise is approximately 1800 in 2006. Taking advantage of the dataset in this survey, we did further analysis on the distribution patterns of the porpoises. Using codes written under the platform R, the longitudinal pattern ( from Yichang to Shanghai) , cross river pattern (from mid channel to bank) and bank preferences pattern ( left or right bank) were identified. The longitudinal distribution map showed that the encounter rate varied between Yichang and Shanghai, including two high density areas ( Wuxue-Sanhaozhou, and Nanjing-Zhenjian g) and one distribution gap area (Shishou-Yueyang, ～ 150 km). The cross river pattern showed that 80％ of the animals occurred within a narrow strip ( ～351 m wide) along the bank line. Moreover, the porpoises showed significant preferences on specific side of the river bank in some sections, e. g. sections from Pengze to Guichi (left bank preference) , Nanjing to Jiangyin ( left bank preference) and Hukou to Pengze ( right bank preference). The distribution patterns imply that Yangtze finless porpoise significantly preferences on habitats. The relationship between distribution patterns and hydrological characteristics was preliminarily discussed in this paper.
Yangtze finless porpoise Distribution Habitat Hydrological characteristic environmental factor
Zhao Xiu jiang Wang Ding
China Three Gorges Corporation, Yichang 443002, China Institute of Hydrobiology, Chinese Academy of China Three Gorges Corporation, Yichang 443002, China
国际会议
The Fourth Yangtze Forum(第四届长江论坛)
南京
英文
198-203
2011-04-18（万方平台首次上网日期，不代表论文的发表时间）