The Yangtze river dolphin, or baji (Lipotes vexillifer), until now listed as Critically Endangered on the IUCN's Red List of Threatened Species, has been declared extinct. Early in 2006, the population was listed at 17. By the end of that year, researchers from the Zoological Society of London cruising the heavily trafficked, polluted river that was its only habitat were unable to find any evidence that even a single individual survived. In September, the IUCN will change its status with the next update of the Red List to to “critically endangered (possibly extinct)”. The last confirmed sighting was in 2002, the same year the only captive specimen died.
It is barely possible that a few individuals linger in tributaries of the Yangtze, but there is no chance they constitute a viable population.
It appears that humanity has driven a documented cetacean species to extinction for the first time.