Abundance and conservation status of the Yangtze finless porpoise in the Yangtze River, China

摘要: middle and lower reaches of the Yangtze River, China. It is only freshwater population porpoises in world currently listed as Endangered by IUCN. In November December 2006 we used two boats line transect methods to survey entire current range population, except for lakes (Poyang Dongting). Sighting results were similar both boats, so pooled all data analyzed them using models a strip model. All produced estimates abundance (1111, 1225 1000). We then added independent number from total estimate approximately 1800 porpoises. Our findings indicate that continues decline its distribution becoming more fragmented. main river slightly less than half surveys between 1984 1991 (which was probably an underestimate). also found apparent gap Yueyang Shishou (similar 150 km), where sightings had previously been common. Continued threats finless include bycatch unregulated unselective fishing, habitat degradation through dredging, pollution noise, vessel strikes water development. Immediate protective measures are urgently needed ensure persistence River. The design analytical developed this study might be appropriate cetaceans other systems. (c) 2008 Elsevier Ltd. rights reserved.