BEIJINg - An international expedition to search for a rare Chinese river
dolphin has ended without a single sighting, and researchers said Wednesday that
the aquatic mammal is facing imminent extinction.
A few of
the white Yangtze River dolphins, known as baiji, may still exist in the massive
waterway that cuts through eastern China, but their numbers are insufficient to
stave off extinction, said August Pfluger, the Swiss co-leader of the
expedition.
"We have to accept the fact that the Baiji is functionally extinct. We lost
the race," Pfluger said in a statement released by the expedition. "It is a
tragedy, a loss not only for China, but for the entire world. We are all
incredibly sad."
The baiji, shy and nearly blind, is one of the world's oldest dolphin
species, dating back some 20 million years. Scientists believe their
disappearance would be the first instance of a large aquatic mammal being driven
to extinction since hunting killed off the Caribbean monk seal circa 1952.
Overfishing and shipping traffic, whose engines interfere with the sonar the
baiji uses to navigate and feed, are likely the main reasons for the mammal's
declining numbers, Pfluger said. Though the Yangtze is polluted, water samples
taken by the expedition every 50 kilometers (30 miles) did not show high
concentrations of toxic substances, the statement said.
For nearly six weeks, Pfluger's team of 30 scientists scoured a heavily
trafficked 1,700-kilometer (1,000-mile) stretch of the Yangtze, where the baiji
once thrived. The expedition's two boats, equipped with high-tech binoculars and
underwater microphones, trailed each other an hour apart without radio contact
so that a sighting by one vessel would not prejudice the other.
Around 400 baiji were believed to be living in the Yangtze in the 1980s. The
last full-fledged search, in 1997, yielded 13 confirmed sightings, and a
fisherman claimed to have seen a baiji in 2004, Pfluger said in an earlier
interview.
At least 20 to 25 baiji would now be needed to give the species a chance to
survive, the group's statement said citing Wang Ding, a hydrobiologist and
China's foremost campaigner for the baiji.
