BEIJING: A painful setback can sometimes act as a catalyst for meaningful change. When the Baiji dolphin named Qiqi died in 2002, there was gloom in conservation circles. Qiqi, the sound of which means “rarity” in Chinese, had been living in captivity since it was rescued from the shallow waters of the Yangtze River in 1980.
The gloom turned to shock five years later, in 2007, when the Royal Society published an article declaring the Baiji functionally extinct. Functional extinction means that the population of a species has declined to an extent that it can no longer sustain reproduction under natural conditions. But the decline of the Baiji spurred the authorities to focus their efforts to conserve the Yangtze finless porpoise, another endangered species living in the Yangtze River ecosystem.
The Royal Society’s article on the Baiji’s decline was based on a sixweek field survey by scientists from seven countries, marking the first global extinction of a large vertebrate in over 50 years. Though it did not mean that the species was completely extinct, it underscored a far bigger problem plaguing the Yangtze River ecosystem.
The Baiji, or the Yangtze River dolphin, is classified as a separate family, which means that its functional extinction represents a significant gap from an evolutionary perspective, according to Wang Ding, secretary-general of the Chinese National Committee for the Man and the Biosphere Programme of UNESCO.
If the apex predator in the Yangtze River ecosystem could no longer survive, other species in the river would also gradually disappear under a domino effect, Wang added.
Wang said the dangers facing the Baiji were noticed almost three decades earlier. “As early as 1978, we became aware of the perilous situation facing the Baiji, with only about 300 dolphins remaining. Our research group was specifically established at that time for the study and conservation of the species,” he said. The government and research institutions invested substantial human and financial resources in rescue efforts, including establishing protected areas and intensifying scientific research. However, the results were less than satisfactory and the number of Baiji dolphins steadily declined.
Qiqi’s death in 2002 followed by the declaration of functional extinction in 2007 sealed the fate of the species. “It was a tremendous tragedy and also a painful lesson,” Wang said. But the silver lining was that it shifted the focus of conservation efforts to the Yangtze finless porpoise — the sole extant cetacean in the Yangtze River.
Compared to the Baiji, the Yangtze finless porpoise is smaller, lacks a dorsal fin, and has a shorter and broader rostrum. Wang Xi, a researcher from the Museum of Aquatic Organisms under the Institute of Hydrobiology, Chinese Academy of Sciences, said that the ancestors of the Yangtze finless porpoise migrated from the oceans hundreds of thousands of years ago, adapted to the freshwater environment and established habitats in the Yangtze River. Like the Baiji, they are also apex predators in the Yangtze ecosystem.
However, the spread of economic development and increase in human activities had led to a sharp decline in Yangtze finless porpoise population. Their numbers dropped from around 2,700 in the early 1990s to just about 1,800 in 2006. In 2012, a field investigation led by the Ministry of Agriculture and Rural Affairs found that only about 1,040 finless porpoises remained — 460 in Poyang Lake, 90 in Dongting Lake and the rest in the main stream of the Yangtze River. The alarming drop in numbers led the International Union for Conservation of Nature to classify the Yangtze finless porpoise as a critically endangered species in 2013.
“The chief cause of the decline was the surge in vessel traffic in the river,” Wang said. “As a cetacean species highly dependent on echolocation for foraging and communication, the Yangtze finless porpoise is extremely sensitive to underwater noise. The noise generated by motorised vessels disrupts their behavioral patterns, impairs echolocation efficiency and even poses lethal threats.” –The Daily Mail-China Daily news exchange item
