Before it was declared extinct during the past decade, the Yangtze River dolphin, or baiji, was among the planet's rarest mammals. One of the world's four freshwater cetaceans, the so-called “Goddess of the Yangtze” was the first aquatic mammal to go extinct in the last 50 years.
The 3,900-mile-long Yangtze River is one of the longest rivers in the world and the longest in China. It is home to the controversial Three Gorges Dam and vital for irrigation, transportation and fresh water.
Several unique or rare species are found only in the Yangtze, such as the Yangtze sturgeon and the Chinese alligator. But they are endangered, slowly succumbing to the same environmental pressures that may have claimed the baiji, including industrial pollution, agricultural run-off and loss of buffer wetlands. Overfishing has also been a major factor.
In 1997, when researchers mounted an expedition to count baiji, only 14 were left in the river. By December 2006, researchers couldn't find any after a six-week 2,000-mile survey.
“The main reason is overfishing,” said August Pfluger, head of the Baiji Foundation, which co-sponsored the expeditions. “The Chinese still use unsustainable fishing methods like dynamite. There's still a lot of illegal fishing, so the dolphins were competing with humans for food.”
Increased development and river traffic also likely contributed to the demise of the dolphins, which had poor eyesight and relied on echolocation to forage for food in the shallows. Samples of pollution levels, however, turned out not to be high enough to cause the death of multiple individuals.
Also facing survival pressures are other river dolphins: the Amazon River dolphin, the La Plata River dolphin (South America) and the Indian River dolphin, in India's Ganges River.
“Globally, a pattern has emerged,” said researcher Zeb Hogan, a National Geographic fellow and TV personality known for his efforts to protect the world's biggest fish. “These large aquatic animals are disappearing.”
— Daniel McGlynn