Le baiji aurait disparu. :bye:Citation En meme temps, quand on voit une photo de la Riviere Jaune a l'automne dernier, on comprend mieux :
China's Rare River Dolphin Now Extinct, Experts Announce
Stefan Lovgren
for National Geographic News
December 14, 2006
The rare Chinese river dolphin has gone extinct, according to scientists who could not find a single one of the animals during a six-week search on China's Yangtze River.
The small, nearly blind white dolphin, also known as the baiji, was nicknamed "the goddess of the Yangtze."
"It's possible that we missed one or two animals [during the search], but we can say the baiji is functionally extinct," August Pfluger, a Swiss economist-turned-naturalist who financed the expedition, said in a telephone interview from Wuhan, China.
"If there are any baiji left in the river, they won't have any chance of survival."
If Pfluger's team is correct, the baiji will be the first large aquatic mammal to have gone extinct since hunting and overfishing killed off the Caribbean monk seal in the 1950s.
Yangtze Dams, Ship Traffic to Blame?
The delicate dolphin, which dates back 20 million years, was found only in China's longest river, the Yangtze.
Using high-tech optical instruments and underwater microphones on two research vessels, the international team of 30 scientists and crew scoured almost 2,175 miles (3,500 kilometers) of the river, from Yichang near the Three Gorges Dam to Shanghai, for any signs of the dolphin.
"When we started, we were really optimistic about finding them, but as each day went by it became increasingly clear that there are no baiji left," Pfluger said.
The dolphin's population had plummeted from about 400 in the late 1980s to less than 100 in the mid-1990s.
The last search for the animal, in 1997, yielded 13 sightings. One fisher claimed to have seen a baiji in September 2004.
The baiji's demise is attributed to overfishing, dam-building, environmental degradation, and ship collisions.
The large-ship traffic on the Yangtze, one of the world's busiest waterways, confounds the sonar that the nearly blind dolphin uses to find food, Pfluger said.
"When you're on the river and you see so many ships, you feel that an animal like a dolphin does not have any chance of survival," he said.
"That's a personal feeling, not a scientific statement."
Although the Yangtze suffers from heavy pollution, it is less polluted than other rivers in China, such as the Yellow River.
Water samples taken by the scientists did not show toxic pollutants in concentrations high enough to have killed the baiji.
Beginning of "Wave of Extinctions"?
Zeb Hogan, who studies large river fish in Asia, says unprecedented use of freshwater rivers has led to the decline of populations of many aquatic species.
"Perhaps nowhere is this pattern more apparent than in populations of species such as river dolphins and large-bodied fish," said Hogan, a researcher with the University of Nevada at Reno and a National Geographic Emerging Explorer based in Phnom Penh, Cambodia.
"Globally, a pattern has emerged; these large aquatic animals are disappearing," Hogan said.
"The world's river dolphins and large freshwater fish face the biggest threats, including overfishing, dams, navigation projects, pollution, and habitat destruction."
The extinction of the baiji dolphin should serve as a wake-up call that more needs to be done to protect river life, Hogan added.
"Unless concrete steps are taken soon to better protect these vulnerable species, this is the beginning of a wave of extinctions that is likely to occur over the next 20 to 30 years."
Finless Porpoise
There are now five species of freshwater dolphins left in the world, four of them living in major freshwater systems in Asia. All are critically endangered.
During their search for the baiji, the scientists also surveyed the population of the endemic Yangtze finless porpoise. They found that there may be fewer than 400 animals left there.
"We have to consider these animals in a better way than we did the baiji," said Pfluger, the expedition organizer.
"We know that if the baiji was doing badly, the finless porpoise is doing badly too. This animal needs our action now. There is no time to waste."
Yesterday, Pfluger said, he watched video footage that he had shot of Qi Qi, a male baiji who was rescued in 1980 and died in captivity in 2002 (see photo).
"I consider myself a strong man," he said. "But when I saw that footage I cried for several minutes. It's just so terribly sad."
