Scientists who are conducting a survey of endangered finless porpoises on the Yangtze River said Monday that they also hope to find white-flag dolphins (baiji or Yangtze River dolphin), a native species that was declared extinct in 2007.

The survey team, who started its research on Sunday, reached a white-flag dolphin nature reserve in central China's Hubei Province on Monday.

"It is not impossible to find white-flag dolphins on the Yangtze River. It's one of the main goals of our survey," said Wang Ding, head of the survey team.

In 2006, a similar survey by Chinese and foreign scientists failed to find white-flag dolphins on the Yangtze River, China's longest.

In 2007, scientists announced that white-flag dolphins had gone "functionally extinct," meaning that the population is too small for the species to effectively reproduce.

"There is still the possibility of finding one or two white-flag dolphins on the Yangtze. We are looking forward to a miracle," said Wang Kexiong, deputy head of the survey team.

The white-flag dolphin is under first-class state protection and is among the 12 most endangered species in the world. In 2004, the body of a white-flag dolphin was found on the bank of the Yangtze, the last known proof of the species' existence. (Xinhua)