"Extinct" fish found reproducing naturally in Colorado waters

Colorado Parks and Wildlife (CPW) has discovered the previously 'extinct' greenback cutthroat trout reproducing naturally in Colorado waters, according to an announcement from Governor Polis.

"After more than a decade of intensive efforts to rescue the greenback cutthroat trout from the brink of extinction, Colorado Parks and Wildlife announced Friday it has discovered that the state fish is naturally reproducing in Herman Gulch, one of the first places the agency stocked it in its native South Platte River drainage," CPW said in a news release.

The greenback cutthroat was first considered extinct in 1937, after succumbing to pollution from mining, pressure from fishing and competition from other trout species, the release said.

The species was rediscovered in 2012, when a small population was found in tiny Bear Creek, located on the southwest edge of Colorado Springs.

"The discovery triggered a massive effort by CPW and the Greenback Recovery Team – a multi-agency group of state and federal aquatic researchers and biologists – to protect the 3½-mile stretch of water holding the only known population of naturally reproducing greenbacks," CPW said.

Each year since the species was rediscovered, CPW has worked to keep a small population in optimal conditions for breeding in a hatchery. Teams then worked to fertilize eggs and stock streams.

"In 2016, CPW began stocking the greenback fry that hatch from those eggs into Herman Gulch west of Denver. Stocking into other streams in the South Platte drainage soon followed. Today, fledgling greenback populations exist in four South Platte basin streams. But only the fish in Herman Gulch have existed long enough to reach adulthood and begin reproducing," officials said.

The discovery of natural reproduction among greenback cutthroats is a huge milestone for CPW, according to the release.

"While we will continue to stock greenback trout from our hatcheries, the fact that they are now successfully reproducing in the wild is exciting for the future of this species. This is a huge wildlife conservation success story and a testament to the world-class wildlife agency Coloradans have in Colorado Parks and Wildlife. Colorado's ecological diversity strengthens our community, supports our anglers, and our thriving outdoor recreation economy," said Governor Jared Polis.

"CPW's staff and our partner agencies have worked for more than a decade to restore this beloved state fish, and today's news truly highlights the success of the work," he said.

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