baiji

The baiji (Lipotes vexillifer) is a possibly extinct species of river dolphin native to the Yangtze river system in China. It is thought to possibly be the first dolphin species driven to extinction due to the impact of humans. This dolphin is listed as "critically endangered: possibly extinct" by the IUCN, has not been definitively seen in over 20 years, and several surveys of the Yangtze have failed to find it. The species is also called the Chinese river dolphin, Yangtze river dolphin, Yangtze dolphin, and whitefin dolphin. The genus name Lipotes means "left behind" and the species epithet vexillifer means "flag bearer". It is nicknamed the "Goddess of the Yangtze" and was regarded as the goddess of protection by local fishermen and boatmen. It is not to be confused with the Chinese white dolphin (Sousa chinensis) or the finless porpoise (Neophocaena phocaenoides). This is the only species in the genus Lipotes.

The baiji population declined drastically in decades as China industrialized and made heavy use of the river for fishing, transportation, and hydroelectricity. Following surveys in the Yangtze River during the 1980s, the baiji was claimed to be the first dolphin species in history driven to extinction by humans. A Conservation Action Plan for Cetaceans of the Yangtze River was approved by the Chinese Government in 2001. Efforts were made to conserve the species, but a late 2006 expedition failed to find any baiji in the river. Organizers declared the baiji functionally extinct. The baiji represents the first documented global extinction of an aquatic "megafaunal" vertebrate in over 50 years since the demise of the Japanese sea lion (Zalophus japonicus) and the Caribbean monk seal (Neomonachus tropicalis) in the 1950s. It also signified the disappearance of an entire mammal family of river dolphins (Lipotidae). The baiji's extinction would be the first recorded extinction of a well-studied cetacean species (it is unclear if some previously extinct varieties were species or subspecies) to be directly attributable to human influence. The baiji is one of a number of extinctions to have taken place due to the degradation of the Yangtze, alongside that of the Chinese paddlefish, as well as the now extinct in the wild Dabry's sturgeon.