After years of speculation and concern, fish biologists (and anglers) who have endeavored for decades to restore the native greenback cutthroat trout–Colorado’s state fish, native to the South Platte River drainage–have learned the truth about the status of this iconic species. I’ll start with the bad news.
All of those “greenback” cutthroats some of us have been catching in remote wilderness streams and lakes east of the Continental Divide aren’t greenbacks after all. Based on the best available genetic science at the time, we thought they were, but they’re not. They’re actually either Colorado River strain cutthroats, which are native to the West Slope, or a more nebulous strain scientists are calling “lineage GB.” I’ll spare you the genetic details, but we now know for certain that they are not native to the rivers east of the Continental Divide.
But there’s good news, too. Scientists have confirmed the existence of a very small population of real, living greenback cutthroat trout in Bear Creek, which is a tiny part of the Arkansas River drainage near Colorado Springs. Ironically, those South Platte River fish were transplanted to Bear Creek over 100 years ago. As far as we know, this population of several hundred fish represents the only true, wild greenbacks on the planet. And they will save the greenbacks from extinction.
All of this information was confirmed yesterday with the release of results of a fascinating study by Dr. Jessica Metcalf (University of Colorado) and her team of colleagues. What they did was compare DNA samples of fish from Bear Creek and throughout Colorado with DNA samples of greenbacks that had been caught in the South Platte more than a century ago, preserved in alcohol, and kept in museums. Using incredibly sensitive genetic technology, they were able to match the historic greenback with this small population in Bear Creek. This is important, because the greenback, which was actually declared extinct in the 1930s, then thought to be “rediscovered” in 1953, has actually been on the verge of extinction all along. Now that the “real fish” has been identified, the potential to restore the true species can move ahead.
Okay, so you might wonder a few things. For starters, why should the average angler care? Trout have been shipped and stocked from one place to another for more than a century. It is what it is, right? I’m sorry, but I think if we have an opportunity to keep a native species in its native range for future generations, we should do it. Granted, our forefathers probably thought they were doing us a favor by shipping rainbow trout east, and brook trout west, but they didn’t have the understanding of how that would impact native fish.
Isn’t it a bummer that so much time and effort has been poured into restoring greenbacks that aren’t true greenbacks? In some ways, sure. But again, those efforts were all based on the best science available. I would also argue that all that stream restoration work has served to increase angler awareness and appreciation of native species throughout the country. And the “infrastructure” is in many places that can support future efforts to restore greenbacks in Colorado.
Lastly, that little stretch of Bear Creek is in an area that sees many recreational uses, including off-road-vehicles. It’s a fragile area that is now clearly a hundred times more important than it might have seemed even a few days ago. I think these findings could lead to more consensus and cooperation among various interest groups to save the greenbacks.
I look at the glass being far more than half full. Thank goodness for the science and the efforts it took to identify the needle in the genetic haystack, and thank goodness there are real, swimming greenbacks around today, and we know where they are. It’s going to take more effort, but the opportunities to save this native species have never been greater.
For more details on the research project including a copy of the study, please visit the University of Colorado News page. For more information on the Greenback Cutthroat Trout Recovery Team, click here. And to learn more about cutthroat conservation and research, click here.