Animals Wildlife Fish Thought to Be Extinct for 70 Years Rediscovered By David DeFranza Updated October 11, 2018 Migrated Image Share Twitter Pinterest Email Animals Wildlife Pets Animal Rights Endangered Species In 1940, a hydroelectric dam was constructed in northern Akita Prefecture, Japan. The project, it was known at the time, would destroy the only native habitat of the black kokanee salmon by making the waters too acidic for the fish to survive. Still, developers went ahead with their plans. A concession was made to protect the species: 100,000 eggs were transported to nearby Lake Saiko. Unfortunately, the transplanted eggs did not hatch and the species quickly became extinct. At least, that's what was thought. Now, a new discovery suggests that a small population of kokanee salmon may have survived."I was really surprised," Tetsuji Nakabo, a professor at Kyoto University who led the team that made the discovery said, "this is a very interesting fish—it's a treasure. We have to protect it and not let it disappear again." The extant population was uncovered in Lake Saiko—the same place the eggs had been deposited 70 years prior—and the population had grown large enough as to be sustainable. Sustainable, that is, as long as the environment in and around the lake can be maintained. Lake Saiko, Nakabo explained, is a popular destination for tourists because of the views of Mount Fuji from its banks. A sudden influx of fisherman, especially, could threaten the survival of the fragile species. In Japan, the salmon is not alone: Other species, including shellfish and plants have been rediscovered since being declared extinct. The official list of extinct species in Japan is set to be revised in 2012.