Yangtze River Dolphin Survey
HSWRI researchers participated in a survey on the Yangtze River, searching for both the Yangtze finless porpoise and the rarer baiji. These porpoises are the only freshwater population of porpoises in the world, have been listed as Endangered by IUCN, and had been legally protected in China since 1975. After surveying the current river range of the population, we estimated that about 1800 Yangtze finless porpoises still survived in 2006, which was less than half the estimate from surveys between 1984 and 1991. The baiji the population had previously been estimated to be between 60 to 250 animals, but we could not find a single baiji. Continued threats to Yangtze finless porpoises include bycatch in unregulated and unselective fishing, habitat degradation through dredging, pollution and noise, vessel strikes and blockage of fish migrations by dams causing a reduction in available prey. We are forced to conclude that the baiji is now likely to be extinct, probably due to unsustainable by-catch in local fisheries. This represented the first global extinction of a large vertebrate for over 50 years, only the fourth disappearance of an entire mammal family since AD 1500, and the first cetacean species to be driven to extinction by human activity.
Akamatsu, T., D. Wang, K. Wang, S. Li, S. Dong, X. Zhao, J. Barlow, B.S. Stewart and M. Richlen. 2008. Estimation of the detection probability for Yangtze finless porpoises (Neophocaena phocaenoides asiaeorientalis) with a passive acoustic method. Journal of the Acoustical Society of America. 123:4403-4411.
Li, S., T. Akamatsu, D. Wang, K. Wang, S. Dong, X. Zhao, Z. Wei, X. Zhang, B. Taylor, L. A. Barrett, S. T. Turvey, R. R. Reeves, B. S. Stewart, M. Richlen, and J. R. Brandon. 2008. Indirect evidence of boat avoidance behavior of Yangtze finless porpoises. Bioacoustics (The International Journal of Animal Sound and its Recording) 17:151-193.
Zhao, X., J. Barlow, B. L. Taylor,R. L. Pitman, K. Wang, Z. Wei, B.S. Stewart, S. T. Turvey, T. Akamatsu, R. R. Reeves, D. Wang. 2008. Abundance and conservation status of the Yangtze finless porpoise in the Yangtze River, China. Biological Conservation. doi:10.1016/j.biocon.2008.09.005