First human-caused extinction of a cetacean species?
The Yangtze River dolphin or baiji (Lipotes vexillifer), an obligate freshwater odontocete known only from the middle-lower Yangtze River system and neighbouring Qiantang River in eastern China, has long been recognized as one of the world's rarest and most threatened mammal species. The status of the baiji has not been investigated since the late 1990s, when the surviving population was estimated to be as low as 13 individuals. An intensive six-week multi-vessel visual and acoustic survey carried out in November-December 2006, covering the entire historical range of the baiji in the main Yangtze channel, failed to find any evidence that the species survives. We are forced to conclude that the baiji is now likely to be extinct, probably due to unsustainable by-catch in local fisheries. This represents 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. Immediate and extreme measures may be necessary to prevent the extinction of other endangered cetaceans, including the sympatric Yangtze finless porpoise (Neophocaena phocaenoides asiaeorientalis).
Turvey
Samuel T
ST
Institute of Zoology, Zoological Society of London, Regent's Park, London NW1 4RY, UK.
Pitman
Robert L
RL
Taylor
Barbara L
BL
Barlow
Jay
J
Akamatsu
Tomonari
T
Barrett
Leigh A
LA
Zhao
Xiujiang
X
Reeves
Randall R
RR
Stewart
Brent S
BS
Wang
Kexiong
K
Wei
Zhuo
Z
Zhang
Xianfeng
X
Pusser
L T
LT
Richlen
Michael
M
Brandon
John R
JR
Wang
Ding
D
D000818:Animals; D002681:China; D004289:Dolphins; D017753:Ecosystem; D053476:Extinction, Biological