Up Just One Creek

A rare Colorado trout may be even more elusive than previously thought, reports The New York Times' Green blog. The greenback cutthroat trout, which is the state fish of Colorado, was thought to live in five wild populations, but a recent study of current fish populations, preserved samples, and historical stocking records indicates that there is only one wild population of the trout, the Times says. The study, published in Molecular Ecology, examined DNA samples from museum greenback cutthroat trout specimens and performed a phylogenetic analysis of the historical samples, which they then compared to modern lineages. The researchers say that the surviving population, which is outside the fish's historical range, is likely descended from fish stocked by a hotel owner to encourage visitors, the Times adds. The other populations are of trout from "phylogenetically and geographically distinct sources," the researchers write.