For instance, a century ago, the Mekong Giant Catfish was found along the entire length of the river from Vietnam to southern China. Since then, however, populations have dropped precipitously. Scientists estimate that the total number of Mekong Giant Catfish has decreased about 90% in just the past two decades.
WWF recently helped broker a voluntary ban on this species with Thai fishers. In Laos as early as 1890, a large fishery developed for the Mekong Giant Catfish but by 1940, declines were observed in northeast Thailand.