Biology and Conservation of Freshwater Cetaceans in Asia (2000)


Survey results from 1989 to 1992 were interpreted as indicating that about 700 finless porpoises (Neophocaena phocaenoides) inhabited the section of the lower Yangtze River between Nanjing and Hukou. The number of individuals seen per kilometer searched (NIPK) was stable in certain river subsections and variable in others. The highest NIPK was in the subsection between Huayang and Hukou. Eighty-nine percent of recorded distances of porpoises from the river bank were 500m or less, indicating that porpoises tend to inhabit the near-bank waters. Our abundance estimate was lower than that from previous surveys, but the suggested decline was not shown to be statistically significant.