Rare Yangtze River dolphin probably extinct
Updated on 08 August 2007
The long-threatened Yangtze River dolphin in China is probably extinct, after desperate efforts to rescue it came too late.
According to an international team of researchers, this would make it the only species of whale, dolphin or porpoise ever to be driven to extinction by human activity. An emergency six week search for the animal brought up no results.
"Ours is the first scientific study which didn't find any. Even if there are a few left we can't find them and we can't do anything to stop their extinction."Dr Samuel Turvey, Zoological Society of London
The freshwater dolphin, or baiji, was last spotted several years ago and an intensive six-week search in late 2006 failed to find any evidence that one of the rarest species on earth survives, said Dr Samuel Turvey, a conservation biologist at the Zoological Society of London, who took part in the search and wrote the paper declaring the extinction.
He said the dolphin's demise, which resulted from pollution, lack of intervention and over-fishing in the eastern Chinese area where the mammal once flourished, might serve as a cautionary tale and should spur governments and scientists to act to save other species verging on extinction.
"We covered the whole range of the dolphin twice. It is difficult to see how we could miss any animals."Dr Samuel Turvey, Zoological Society of London
Last sightings
The last confirmed baiji sighting was 2002, although there have been a handful of unconfirmed sightings since then. The last baiji in captivity died in 2002, Turvey said.
During the six-week search, the team carried out both visual and acoustic surveys and used two boats to twice cover the dolphin's 1,669 kilometre range stretching from the city of Yichang just downstream from the Three Gorges dam to Shanghai.
The last such survey conducted from 1997 to 1999 turned up 13 of the mammals, but Turvey said fishing, pollution and boat traffic in the busy river, home to about 10 percent of the world's population, has likely meant the baiji's end.
"One really needs to learn from this to make sure future conservation efforts are more dynamic. There has always been so much focus on 'save the whale' and 'prevent whaling' that it has led to these range-restricted shallow cetaceans slipping through the crack."Dr Samuel Turvey, Zoological Society of London
Learning the lessons
The dolphins will now be classified as critically endangered and possibly extinct but Turvey said there is little chance any remaining baiji are alive.
Researchers have known for years about the dolphin's precarious situation, but indecision about how best to save the species meant little was actually done, he said. He added that this underscores the need to act quickly to prevent the extinction of other similar shallow-water aquatic mammals like the vaquita found in the Sea of Cortez and the Yangtze finless porpoise.
