¿ìè¶ÌÊÓƵ

Final farewell to the Yangzte river dolphin or baiji, a mysterious yet majestic creature we may never again see alive.

An extensive survey in December 2006 failed to find even one surviving animal. Then on 19 August, a showed a white dolphin-like streak that briefly broke the surface of the muddy waters.

Sadly, even if it was a baiji, this single and still disputed sighting means only that its demise is more protracted than we thought. Even if a pair for breeding were miraculously found, past attempts to establish a captive population all failed. The Yangzte river is too busy, polluted and overfished for any remaining animals to survive much longer.

That makes the baiji the first cetacean species to be driven extinct by humans. We have come close before: whalers wiped out the north Atlantic population of the grey whale in the 17th century, but the species survived elsewhere. For a river dolphin like the baiji – sole representative of the Lipotidae family – there is no elsewhere.

The baiji’s fate is all the more depressing because we had decades of warnings about its plight, and several attempts were made to conserve it. If so much effort was in vain, what hope is there for other endangered cetaceans such as the Gulf of California porpoise, or vaquita?

In November, biologists reported that there are just and that it is likely to go extinct in two years unless immediate action is taken to prevent the animals perishing in shrimping nets. The report received almost no coverage. In the space of just three years, the number of cetacean species wiped out by humans may jump from zero to two.

Read all the biggest stories of 2007 in our News Review

Endangered species – Learn more about the conservation battle in our comprehensive special report.