Environment

Yangtze River dolphin's days are numbered

PUBLISHED : Tuesday, 22 March, 2005, 12:00am
UPDATED : Tuesday, 22 March, 2005, 12:00am

On World Water Day, the Post looks at two controversial issues involving China's troubled waterways


Pollution, the construction of dams and entanglement in fishing nets have drastically reduced the number of Yangtze River dolphins, a world environmental group warned on the eve of World Water Day.


The number of the freshwater mammals was put at 13 by a 1997 survey, according to the WWF global conservation group.


The WWF said this made it the world's most endangered dolphin or porpoise and the second-most endangered of all species.


The number, revealed for the first time, is significantly lower than the 100-odd count given by mainland authorities. It also reflects the degraded state of the 6,300km Yangtze River, China's longest.


'River dolphins are the 'watchdogs' of the water,' says Jamie Pittock, director of the WWF's Global Freshwater Programme.


'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 [the river].'


The main threats of extinction to the mammals include industrial, agricultural and human waste as well as dams, which restrict their movement.


Accidental netting by fishermen is also contributing to the animal's demise, the Switzerland-based organisation said in the lead-up to today's World Water Day.


'Theoretically, when a species' number dwindles to below 25, it is doomed because of inbreeding and genetic degeneration,' says Wang Limin, head of a WWF-HSBC Yangtze River conservation programme.


'But despite that we won't give up as there is also a ray of hope,' he said.


The protection of the Yangtze River dolphin can benefit other species and the livelihoods of the millions of people living along its banks.


'In this particular case, the protection of the dolphins demands a comprehensive approach and the restoration of the river's overall ecological environment.'


Dr Wang is working to re-link the Yangtze proper with oxbows - wetland areas regarded as havens for river dolphins - in the Tian'e-zhou National Dolphin Reserve in Hunan .


The water flow is often restricted by dykes, which means the wetlands eventually die.


The only Yangtze River dolphin in the national reserve died in 1996 while trying to leave 'as it was lonely and anxious', Dr Wang said. It became tangled in a net.


However, about 20 finless porpoises, another species in decline, continue to live there. Less than 2,000 of the porpoises remain in the river.


The Yangtze River is the only home of the aptly named dolphin species, which has an estimated history of 25 million years. There were 400 dolphins in the river in the early 1980s, but the figure had been halved within a decade.


The WWF also warned yesterday against pollution and gillnet entanglement in other Asian rivers.


Fewer than 2,000 Ganges River dolphins remain in the 6,000km Ganges and Brahmaputra river system in India.


A similar number of Irrawaddy dolphins continue to survive and in Pakistan, about 1,100 freshwater dolphins live in five areas.