The Baiji

"'The last confirmed sighting of a Baiji was in 2002, the same year that the sole surviving captive animal — a male called Qi Qi — died. Since then, fishermen have reported seeing Yangtze river dolphins on three occasions but scientists says it is impossible to confirm the sightings.' A scientific expedition in 2006 carried out an extensive survey along Yangtze from Yichang to Shanghai but the team failed to find any evidence that the species survives and concluded that the Yangtze river dolphin is probably extinct a victim of by-catch in local fisheries and the rapid development and degradation of the Yangtze River."