Dolphin 'probably extinct'
2007-08-08 11:34
London - The long-threatened Yangtze
River dolphin in China is probably extinct, according to an
international team of researchers who said this would mark the
first whale or dolphin to be wiped out due to human activity.
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 Samuel Turvey, a conservation biologist, at the
Zoological Society of London, who took part in the search.
He said the dolphin's demise - which resulted from
overfishing, pollution and lack of intervention - might serve
as a cautionary tale and should spur governments and scientists
to act to save other species verging on extinction.
"Ours is the first scientific study which didn't find any,"
he said. "Even if there are a few left
we can't find them and we can't do anything to stop their
extinction."
The team, which published its findings in the Journal of the
Royal Society Biology Letters on Wednesday, included researchers
from the United States, Britain, Japan and China. The survey was
also authorised by the Chinese government, Turvey said.
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.
Indecision 'meant little was actually done'
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 669km 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% of the
world's population, has likely meant the baiji's end.
"We covered the whole range of the dolphin twice," Turvey
said. "It is difficult to see how we could miss any animals."
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 added.
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, Turvey said.
"One really needs to learn from this to make sure future
conservation efforts are more dynamic," he said. "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."