Last call

Wang Ding is worried.

"Today finless porpoises are in the same state as the Baiji 20 years ago," he said during the 2006 Yangtze Freshwater Dolphin Expedition. Up until the third day of the search, the scientists only found 20 porpoises - far less than the 100 they expected. There are only around 1,400 porpoises left.

A threatened species on the Red List of the International Union for Conservation of Nature, the finless porpoise is currently a Grade-2 protected species in China, and is being upgraded to Grade-1 status. Some scientists predict that if nothing is done to stop the environmental degradation in the Yangtze River, the porpoise will be gone in less than 100 years.

The finless porpoise is a small cetacean found in rivers and coastal areas in South and East Asia. There are three distinct subspecies. One is found in the Indian Ocean and South China Sea (Neophocaena phocaenoides phocaenoides); another is found in northern China, South Korea and along the coast of Japan (Neophocaena phocaenoides sunameri); and a freshwater subspecies (Neophocaena phocaenoides asiaeorientalis) is found in the lower and middle reaches of the Yangtze River, as well as the Poyang and Dongting lakes.

Although the finless porpoise and the Baiji are not related, they share the same habitat and the same food. Thus, the Baiji can be found where there are plenty of porpoises, and vice versa. To conserve both species, it is crucial to restore the fish stock in the Yangtze.

Presently, land-reclamation projects have reduced the surface area of the water, while dam construction has prevented the migration of four major fish species - the black carp, grass carp, silver carp and bighead carp. The damming has also flooded eight key spawning sites for these fish, reducing fish fry quantities by 97 percent.

"There is now hardly any plankton in the Yangtze River," says Dr Beat Mueller, a Swiss scientist on the 2006 Yangtze Freshwater Dolphin Expedition. "I put a net in the river to collect plankton for 10 hours, and all I got were two shrimp less than a centimeter long. It's hard to imagine how fish can survive in waters like that."

However, there may yet be reason to hope. In July 2005, a finless porpoise under the care of the Institute of Hydrobiology gave birth to the first finless porpoise born in captivity, rekindling hope for this endangered species.

River dolphins represent a rather primitive form of cetaceans, and are classified into four natural families. The Ganges and Indus river dolphin are limited to the South Asia subcontinent; the Amazon river dolphin is found only in the Amazon and Orinoco rivers; the La Plata dolphin lives in estuaries on the west coast of the Atlantic Ocean; and the Baiji, the most endangered river dolphin, is exclusive to China.

Except for the Amazon dolphin, the other freshwater dolphins are found in densely populated areas - these include the Indus, Yangtze and Indian rivers, where one-sixth of the world population resides.