No young Chinese paddlefish have been seen in the wild since 1995, and there have been no sightings of a wild Chinese paddlefish of any size since 2003—leading many to fear that the megafish is already extinct.
Even if evidence surfaces that some paddlefish remain, scientists fear that their numbers are already so low that they will be unable to reproduce successfully.
Chinese paddlefish are thought by many to be the world's largest freshwater fish, with reports of individuals reaching a mind-boggling 23 feet (7 meters) in length and weighing half a ton (450 kilograms). They have long, silver-gray bodies, very large mouths, and a long, wide snout that resembles a paddle. The snouts contain sensors that help them locate the small fish and crustaceans they survive on.
These sleek giants, which the Chinese call sword-billed sturgeons, were once commonly seen and caught in China's Yangtze River. Their enormous bulk and plentiful flesh made them a popular target for fishermen and a welcome addition to dinner tables, including those of ancient Chinese emperors. But the construction of a dam in the 1980s forever altered the Yangtze River habitat of paddlefish and other notable species.
The dam, part of the Gezhouba hydroelectric project, created an impassible barrier between the lower Yangtze River and delta region, where the paddlefish live most of the year, and its spawning grounds in the upper river.
In the years since the Gezhouba Dam was completed, the enormous Three Gorges Dam has further fragmented the Yangtze, and future projects will continue to threaten the paddlefish's habitat.
The fate of the critically endangered megafish now likely lies in captive breeding. Such programs have been attempted in the past, but they present many challenges, not the least of which is finding suitable wild adults that have lately proven so elusive.