Swansong: Qi Qi, a rare Baiji dolphin who was rescued from the Yangtzi river in 1980 after being beached and injured, swimming in Wuhan Baiji Aquarium where she lived for 22 years before dying of old age in 2002.

Credit: iStockphoto

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SHANGHAI: China's rapid development has likely pushed the freshwater baiji dolphin to extinction. It is perhaps the first whale or dolphin to have been pushed to extinction by human hands.

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

Fruitless search

Scientists from China, Japan, Britain and the United States failed to find the white dolphin, known as the baiji (Lipotes vexillifer) or Yangtze River dolphin, during a six-week search of its natural habitat in the river last year. They report the results of the survey in the current Biology Letters.

"This result means the baiji is likely extinct," said Wang Ding, who led the survey and is one of the world's leading expert on the species at the Chinese Academy of Sciences in Beijing.

The dolphin – a 20-million-year-old species – has been a victim of devastating pollution, illegal fishing and heavy cargo traffic on the Yangtze, Wang said. The findings mean the baiji is likely also the first mammal to become extinct in more than 50 years. It is the cousin of the Ganges River dolphin (Platanista gangetica) of India, which is also on the endangered list.

Wang, 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.

"Extreme human pressure"

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.
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