Though presumed to be extinct by 1937, several wild populations of what were thought to be greenback cutthroat trout were discovered in the South Platte and Arkansas basins starting in the late 1950s. These discoveries launched an aggressive conservation campaign that replicated those populations across the landscape so that they could be down-listed from endangered to threatened under the Endangered Species Act. Momentum for preserving these native jewels continued to build, and in 1996, the greenback was designated as Colorado's state fish. Efforts to establish new populations were proceeding along a track that suggested the recovery plan benchmarks might soon be met, and the subspecies could be delisted entirely. Recent genetic work on museum and extant populations however suggests that in fact the true native cutthroat of the South Platte basin (and heir to the name greenback cutthroat trout), can be found in only a single stream outside their native range. Aggressive recovery efforts have been implemented to replicate this population, with the first reintroduction in the wild occurring in August 2014.
CPW biologist Boyd Wright releases native greenback cutthroat trout into Zimmerman Lake on August 8th, 2014 after implementing a successful reclamation project the previous summer.