Colorado Protected the Wrong Trout for Years: Can We Save the Greenback Cutthroat Now?
These are the tools you'll need to extract sperm from some of the rarest trout in the world: a towel, a small glass dish like those used on cooking shows to hold chopped ingredients, gloves, fish tranquilizers and your thumb.
Courtesy of Doug Krieger An estimated 500 to 700 greenback cutthroat trout live in Bear Creek.
On a recent day, no fewer than ten biologists, staff members and volunteers wearing waterproof waders and various shades of park-ranger khaki gather at the Leadville National Fish Hatchery to do just that. The inside of the historic building is chilly and loud due to the constant rush of water cascading into the open-top fish troughs.
Workers use a net to transfer the fish to a bin filled with water and sedative. Swimming soon gives way to floating, and one by one they scoop the sleeping trout out of the bin and pat them down with a purple bath towel. Once an individual fish is sufficiently dried (water will activate the sperm, and active sperm can only live for twenty to thirty seconds), it's handed to a biologist tasked with cradling the fish's body in one hand and using the thumb of the other hand to stroke its underbelly in a downward motion, almost as if he were trying to squeeze the last bit of toothpaste out of the tube. If the biologist is lucky, a few drops of milky-white "milt" will dribble out of the trout, drip down its back fin and make a small puddle in the glass bowl.
The trout that the biologists are working with are the offspring of fish from Bear Creek just outside of Colorado Springs. The creek is home to the state's last known population of greenback cutthroat trout, which Colorado designated as the state fish in 1994.
At least it's the last known population as far as scientists can tell.
From the time the greenbacks were included on the first-ever Endangered Species Act list in 1973, state and federal biologists have worked diligently to preserve and propagate them. It's not that the greenbacks are more precious than any other cutthroat subspecies; it's that we came so close to losing them, explains Kevin Rogers, an aquatic-research scientist with Colorado Parks and Wildlife.
"It's more of a legacy thing," he adds. "This is part of our evolutionary history in the state.... I'd like to continue to fish for these things that belonged here."
Doug Krieger, a senior aquatic biologist with Colorado Parks and Wildlife, agrees. "In some ways, they're the canary in the coal mine," he says of endangered and threatened species like the greenbacks. "If you protect them, you've protected the environment."
But in 2007, a University of Colorado study cast doubt on whether the greenbacks they were saving were actually greenbacks at all. A follow-up study published in 2012 confirmed their worst fears: The fish they'd spent so much time on was actually a different subspecies of cutthroat trout. In other words, they'd been saving the wrong fish.
What's more, researchers concluded that the right fish live only in a narrow, four-mile stretch of shallow Bear Creek, and counts showed that there were only about 700 of them left. The discovery was a blow to the biologists who had spent their careers believing they were bringing a native species back from the brink of extinction.
But those who continue the quest to save this small, spotted trout with the brilliant red-orange streaks hope that their latest efforts will finally put the drama to rest. Since 2008, biologists have been raising greenbacks in hatcheries with the goal of increasing their ranks. They started with just 65 fish from Bear Creek, and thanks to the hard work of many talented thumbs, the population has grown to approximately 3,800 greenbacks living in captivity.
However, many of the hatchery fish suffer from deformities not seen in the wild: having only one eye, for instance, or two chins. The defects are thought to be the result of more than a century of inbreeding among the last surviving population. In Bear Creek, deformed fish often die. But in the hatcheries, where the fish are more pampered, they can live to adulthood.
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.
"We hope we have the right answer now, but there's still a tiny part of me that's skeptical," Krieger says of the current recovery efforts. "I don't want to be so arrogant as to consider that we have the absolute final answer."