Now experts at the institute are studying the feasibility of transporting the survivors to a natural preserve in a Noah's Ark-like operation, said Wang, one of China's leading authorities on the nearly decimated species.
The sighting provides a small ray of hope for scientists who had previously given up on the baiji.
"The baiji is functionally extinct," concluded August Pfluger, head of the Swiss-based baiji.org foundation and co-organizer of the 2,200-mile (3,500-kilometer expedition), at the time.
"It is a tragedy, a loss not only for China, but for the entire world."
According to Wang, baiji dolphins apparently lived and flourished in the Yangtze for more than 19 million years before humans arrived on the scene.
Beat Mueller is a geochemist at the Swiss Federal Institute of Aquatic Science and Technology who was also part of the 2006 baiji expedition.
"The disappearance and extinction of such highly evolved endemic mammals as the white Yangtze River dolphin [baiji], the finless porpoise, or the Chinese sturgeon from the Yangtze River can be attributed to a multitude of circumstances, such as the deterioration and loss of their natural habitats, overfishing of the river, the heavy freight ship traffic, and others," Mueller said.
"Increasing concentrations of anthropogenic chemicals may just be one additional factor," he added. But Wang said he and others at the hydrobiology institute are now convinced that the last survivors of the dolphin might be found along small tributaries of the Yangtze in eastern China's Anhui Province, where the amateur video was shot in mid-August.
Call to Action
Conservation specialists at the hydrobiology institute, which is part of the Chinese Academy of Sciences, are preparing to search those waterways, pending approval from the Chinese Ministry of Agriculture.
"We may try to catch the baiji dolphins and move them into our semi-natural Tian-e-Zhou Reserve, which is located along an oxbow [U-shaped curve] of the Yangtze River, to put them under full protection," Wang said.
According to Karen Baragona, a specialist on the Yangtze at the World Wildlife Fund, the keys to the survival of the baiji are conserving oxbow lakes in the central Yangtze, creating a network of nature reserves along the river, and managing the river's entire ecosystem from a holistic perspective.
"This sighting presents a last hope that the baiji may not go the way of the dodo bird," Baragona said in a statement.
"Other species have been brought back from the brink of extinction, like the southern right whale and white rhinos, but only through the most intensive conservation efforts."
Wang, with the help of the baiji.org group, might even attempt to engineer the recovery of the dolphins through a captive breeding program.
The Baiji Conservation Aquarium has already scored small successes with a similar breeding scheme aimed at averting the extinction of the endangered Yangtze finless porpoise.
Two finless calves have been born at the aquarium since it was set up two years ago.
But Wang warned that the battle to save the baiji is anything but guaranteed.
"The chances of saving the baiji are really small," he said. "But we have to try our best to save the last baiji, even if we know it may be a mission impossible."