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  Yahoo News 8 Aug 07
China's white dolphin likely extinct

Yahoo News 8 Aug 07
Yangtze River dolphin probably extinct: study
By Michael Kahn

Yahoo News 8 Aug 07
Dolphin Species Goes Extinct Due to Humans
Charles Q. Choi

BBC 7 Aug 07
Rare river dolphin 'now extinct'

A freshwater dolphin found only in China is now "likely to be extinct", a team of scientists has concluded.

The researchers failed to spot any Yangtze river dolphins, also known as baijis, during an extensive six-week survey of the mammals' habitat.

The team, writing in the Royal Society Biology Letters journals, blamed unregulated fishing as the main reason behind the dolphins' demise.

It would be the first extinction of a large vertebrate for over 50 years. The World Conservation Union's Red List of Threaten Species currently classifies the creature as "critically endangered".

Sam Turvey of the Zoological Society of London (ZSL), one of the paper's co-authors, described the findings as a "shocking tragedy".

"The Yangtze river dolphin was a remarkable mammal that separated from all other species over 20 million years ago," Dr Turvey explained. "This extinction represents the disappearance of a complete branch of the evolutionary tree of life and emphasises that we have yet to take full responsibility in our role as guardians of the planet."

'Incidental impact'

The species (Lipotes vexillifer) was the only remaining member of the Lipotidae, an ancient mammal family that is understood to have separated from other marine mammals, including whales, dolphins and porpoises, about 40-20 million years ago.

The white, freshwater dolphin had a long, narrow beak and low dorsal fin; lived in groups of three or four and fed on fish.

The team carried out six-week visual and acoustic survey, using two research vessels, in November and December 2006.

"While it is conceivable that a couple of surviving individuals were missed by the survey teams," the team wrote, "our inability to detect any baiji despite this intensive search effort indicates that the prospect of finding and translocating them to a [reserve] has all but vanished."

The scientists added that there were a number of human activities that caused baiji numbers to decline, including construction of dams and boat collisions.

"However, the primary factor was probably unsustainable by-catch in local fisheries, which used rolling hooks, nets and electrofishing," they suggested.

"Unlike most historical-era extinctions of large bodied animals, the baiji was the victim not of active persecution but incidental mortality resulting from massive-scale human environmental impacts - primarily uncontrolled and unselective fishing," the researchers concluded.

Yahoo News 8 Aug 07
Yangtze River dolphin probably extinct: study
By Michael Kahn

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 in a telephone interview. "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 authorized 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.

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 kilometer 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.

"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."

Yahoo News 8 Aug 07
China's white dolphin likely extinct

China's rapid industrialisation has likely made extinct a species of fresh water dolphin that had been on Earth for over 20 million years, Chinese and British biologists said Wednesday.

Scientists from China, Japan, Britain and the United States failed to find the white dolphin, known as the baiji, during a six-week search of its natural habitat in the Yangtze river last year.

"This result means the baiji is likely extinct," Wang Ding, co-author of the survey and one of the world's leading experts on the species, told AFP.

The dolphin was a victim of devastating pollution, illegal fishing and heavy cargo traffic on the Yangtze, Wang said.

The findings mean the baiji is likely the first mammal to become extinct in more than 50 years. It is the cousin of the bottlenose dolphin, which is also on the critically endangered list.

Wang, from the Chinese Academy of Sciences, emphasised that not all hope was lost for the dolphin, which had made its home along the lower reaches of China's now heavily polluted Yangtze River for more than 20 million years.

"We are not saying the baiji is already gone," he said. But he lamented that further searches this year had failed to find any sign of the dolphin.

Wang said that a letter written by the survey team had been published in the latest issue of the Royal Society Biology Letters journal in Britain to confirm the dolphin was believed to be extinct.

The baiji, identifiable by its long, teeth-filled snout and low dorsal fin, was last officially sighted more than two years ago. The last confirmed count by a research team was conducted in 1997, when just 13 were recorded.

Up to 5,000 baiji were believed to have lived in the Yangtze less than a century ago, according to the baiji.org website, which was established by a range of international conservation groups.

"The decline in the baiji population has been caused by extreme human pressure on its freshwater habitat," the website said, blaming illegal fishing and massive discharges of industrial and agricultural waste into the river.

Other rare species that live in the Yangtze, such as the Chinese sturgeon and the finless porpoise, are also in danger of extinction.

The British-based zoologist who also worked on the six-week search meanwhile said the loss of the Yangste dolphin was a huge blow.

"The loss of such a unique and charismatic species is a shocking tragedy," said co-author Sam Turvey of the Zoological Society of London. "The Yangtze River dolphin was a remarkable mammal that separated from all other species over 20 million years ago."

International environmental group WWF has warned that river dolphins are key indicators of a river's health and of the availability of clean water for people living on its banks.

"River dolphins are the watchdogs of the water," said Jamie Pittock, head of WWF's Global Freshwater Programme in a recent alert over their fate. "The high levels of toxic pollutants accumulating in their bodies are a stark warning of poor water quality. This is a problem for both dolphins and the people dependent on these rivers," he added.

Turvey added: "This extinction represents the disappearance of a complete branch of the evolutionary tree of life and emphasises that we have yet to take full responsibility in our role as guardians of the planet."

Yahoo News 8 Aug 07
Dolphin Species Goes Extinct Due to Humans
Charles Q. Choi Special to LiveScience LiveScience.com

The Yangtze River dolphin is now almost certainly extinct, making it the first dolphin that humans drove to extinction, scientists have now concluded after an intense search for the endangered species.

The loss also represents the first global extinction of megafauna—any creature larger than about 200 pounds (100 kilograms)—for more than 50 years, since the disappearance of the Caribbean monk seal (Monachus tropicalis).

The Yangtze River dolphin or baiji (Lipotes vexillifer) of China has long been recognized as one of the world's most rare and threatened mammal species.

"It's a relic species, more than 20 million years old, that persisted through the most amazing kinds of changes in the planet," said marine biologist Barbara Taylor at the National Oceanic and Atmospheric Administration's Fisheries Service. "It's been here longer than the Andes Mountains have been on Earth."

In 1999, the surviving baiji population was estimated to be as low as just 13 dolphins, compared to 400 known baiji in 1981. The last confirmed glimpse of a baiji was documented by a photo taken in 2002, although unverified sightings were reported as recently as 2006.

An international team of scientists conducted an intense six-week search for the dolphin in two research vessels during November and December 2006, covering the entire known range of the baiji in the 1,037-mile (1,669-kilometer) main channel of the Yangtze River.

The researchers and their instruments failed to see or hear any evidence that the dolphin survives.

"It was a surprise to everyone on the expedition that we didn't have any sightings at all, that the extinction just happened so quickly," Taylor recalled.

This would make the baiji the first cetacean—that is, dolphin, porpoise or whale—to go extinct because of humans.

The species was probably driven to extinction by harmful fishing practices that were not even devised to harm the dolphins, such as the use of gill nets, rolling hooks or electrical stunning.

The findings are detailed Aug. 7 in the journal Biology Letters. "In the past, you had this out-of-control whaling that still didn't result in any extinctions, but these accidental deaths, which are much less visible to people, are much more insidious," Taylor said.

Even if any baiji exist that scientists did not find, the continued deterioration of the Yangtze region's ecosystem—home to roughly 10 percent of the world's human population—means the species has no hope of even short-term survival as a viable population, the researchers added.

"To help save the endangered Yangtze finless porpoises (Neophocaena phocaenoides asiaeorientalis) that also live in the river, we'll likely have to keep them in lake preserves or raise them in captivity, because the situation in that river doesn't look like it can be controlled at this point," Taylor explained.

With the loss of the Yangtze River dolphin, the world's most critically endangered cetacean species now is the vaquita or Gulf of California porpoise (Phocoena sinus), of which 250 survive.

The vaquita and other coastal dolphins around the world now face the same peril that claimed the baiji—accidental deaths from fishing.

"We have to find a way to let small-time fishermen put food on their tables that doesn't involve putting gill nets in the water that decimate these species," Taylor said. "Unless we figure out a way to deal with this problem, the baiji may be the first in quite a long line of animals to face extinction."
links Related articles on Dolphins and other cetaceans and large fishes.
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