State and federal biologists have been trying to protect the greenback cutthroat trout ever since it was included on the first-ever Endangered Species Act list in 1973. But in 2007, a University of Colorado study cast doubt on whether the fish they'd been saving were actually greenbacks at all. Another study in 2012 confirmed their worst fears: The greenbacks they'd spent so much time on were a more common subspecies of cutthroat trout. Now scientists are trying again, using fish that are believed to be the last true greenback cutthroats in Colorado. Later this summer, biologists plan to release a thousand hatchery-raised greenbacks into Zimmerman Lake, about an hour and a half west of Fort Collins. The hope is that the fittest among them will survive and spawn a new generation of Colorado's state fish. Read about these efforts and more in Melanie Asmar's “One Fish, Two Fish,” now posted on the Latest Word.