The search for the rare Yangtze River dolphin by an international team of marine biologists is reaching the conclusion that it may no longer exist. The river dolphin, a feature of Asia's mightiest river, is probably now extinct and died out only recently, the experts said.

There were reports of a sighting earlier this year, but it couldn't be verified. On this expedition the researchers have seen none so far but say they haven't given up hope. The river dolphin, also known as the baiji, has been an endangered species for more than 10 years and its dwindling population prompted an exhaustive search called the Yangtze Freshwater Dolphin Expedition 2006. The effort involves two research vessels and covers the entire historic range of the dolphin, the boats departed in early November. They sailed upstream to Yichang in Hubei, then downstream to Shanghai and are now returning to Wuhan, a round trip of more than 3,400 kilometers. The expedition is expected to arrive in Wuhan around the middle of this month.

The expedition boats travel one hour apart and along separate banks. Each vessel has a team of seven observers operating in rotation, four watching through daylight hours with high-performance optics. Hydrophone technology is also being used to detect the dolphins distinctive acoustic signals but so far, two-thirds of the way through the trip, none has been heard. These animals are practically blind, hunt with sound but can communicate with each other over a large distance. However, due to the noise that the shipping on the river creates both of these functions must have been almost impossible.

This isn't just a loss for China but for all mankind.

Source: shanghaidaily