Rare Dolphin's "Extinction" A Red Flag for Biodiversity Loss

The international expedition that recently declared the Yangtze River dolphin, or baiji, “functionally extinct” has called the disappearance of the species “a loss not only for China, but for the entire world.” The rare white cetacean had been living in the middle and lower reaches of the Yangtze and its tributaries for more than 20 million years, where it survived at the top of the aquatic food chain. But with the Yangtze river basin now home to nearly 400 million people—roughly a third of China’s population—unchecked human activities have gradually destroyed the animal’s habitat, according to scientists with the Institute of Hydrology at the China Academy of Sciences.

The expedition team spent 38 days in November and December scouring a 3,400-kilometer segment of the Yangtze River with hi-tech optical and acoustic equipment, but found no trace of the dolphin. A 2004 report from a conservation workshop concluded that the number of baiji in the river has declined rapidly and continuously since the 1970s. Whereas some 300 of the dolphins were reported in the mid-1980s, a follow-up survey in 1997 recorded only 13 individuals.

The dramatic decline in the baiji population has been linked with an increase in the amount of wastewater discharged into the Yangtze in recent decades. In 2005, an estimated 29 billion tons of wastewater from industrial and municipal sources entered the river, up from some 15 billion tons in the late 1980s, according to the Yangtze River Water Resources Committee. Most of the wastewater is poorly treated, with an average treatment rate of only 15 percent. It is estimated to be causing eutrophication in more than half the lakes in the basin and endangering some 500 municipal drinking water sources along the river.

Illegal fishing and busy vessel traffic are also considered culprits behind the baiji’s disappearance. But scientists say the greatest threat to the dolphin is the construction of large dams in the river basin. In recent decades, the Chinese government has considered dams a vital means of securing water, electricity, and energy supplies to support the country’s roaring economic development. But the dams have altered the river’s hydrology, with long-term impacts on freshwater species and their habitats. The baiji, for example, needs year-round water flow to move freely between deep riverine pools and to feed successfully.

A 2004 study conducted jointly by WWF and the World Resources Institute ranks the Yangtze River basin the most dam-filled basin in the world, with 46 large dams currently planned or under construction, in addition to a significant number of existing dams. The study identified the basin as being at severe risk of ecological degradation, due to population pressure and the loss of habitat for birds and the Yangtze River dolphin. The basin is currently home to rich terrestrial and freshwater biodiversity, including an estimated 322 fish species and 169 amphibian species.

“It’s never too late to mend the fence, even if you have lost some sheep,” the old Chinese saying goes. The Chinese Ministry of Agriculture approved a plan to preserve the baiji back in 2001 but did not carry it out due to lack of funding; it has learned from this oversight by recently launching a two-year survey of rare fish species in a nature reserve in the upper reaches of the Yangtze River. This is the first-ever effort by the Ministry to understand the river’s hydrological and environmental conditions, including the economic and ecological status of its fish species.

In addition, the State Environmental Protection Administration (SEPA) is cooperating with The Nature Conservancy, a U.S.-based conservation organization, to launch a two-phase project to assess the threats to China’s endangered species and ecosystems. The first phase of the project will include an evaluation of biodiversity in the upper Yangtze basin and develop recommendations and strategies for conservation action, which will be taken nationwide in the second phase. SEPA expects the project results to support government decision-making on natural resource conservation and sustainable development.

Yet public awareness of the need for species conservation lags considerably in China. The media reported that during the first five months of 2005, only five people made donations to the Wuhan-based Baiji Conservation Foundation, the first foundation in China to support the endangered dolphin. Thus, there remains great potential for the media, nongovernmental organizations, and educational institutions to work together and play more active roles in engaging the public in biodiversity conservation in China