Restoring Colorado’s state fish to its native waters could redefine species conservation—if we can avoid the mistakes of the past.
I usually carry a wallet full of flies when I try this hard to sight fish. But today I stalk the banks of Bear Creek equipped only with a pair of polarized sunglasses that reveal nothing—not a single fluttering fin—in the rushing waters. This boulder-filled gully is the only place in Colorado where greenback cutthroat trout still swim free and wild. I’ve flubbed my chance to glimpse the Colorado native.
An estimated 750 greenbacks live in Bear Creek, 20 minutes from downtown Colorado Springs. Aside from a few hatchery populations, this is all that remains of Colorado’s state fish, now the world’s rarest trout. From photos, I know the greenback has an olive green spine, a pointillist’s smattering of chocolate brown spots, and racy orange fins. Its cheeks are also orange, as if the reclusive greenback blushed before the camera.
Some 150 years ago, greenback cutthroat trout flourished in Colorado, populating the cold, clear headwaters of two river basins: the South Platte River, which runs from mountain grasslands southwest of Denver to its confluence with the North Platte in Nebraska, and the Arkansas River, which originates in Colorado’s Collegiate Peaks and flows southeast to the Mississippi River. Like Darwin’s finches, 14 unique cutthroat subspecies evolved over hundreds of thousands of years throughout the mountains of western North America. Then nineteenth-century pioneers arrived, cutting timber, digging mines, and transferring indigenous fish to unfamiliar waters. As civilization advanced, sport and sustenance fishermen introduced brook, brown, and rainbow trout—powerful, voracious invaders that muscled out the natives. Colorado’s yellowfin cutthroats went extinct. Nevada’s state fish, the Lahontan cutthroat, is listed as a threatened species. California’s Paiute cutthroat trout was brought to the brink of extinction after rainbows invaded its habitat. But harmful meddling is not only a trout story: Red shiners, a bait fish stocked in Arizona’s Lake Mead, first moved upstream into Utah’s Virgin River in the 1960s and have since endangered native woundfin minnows. In the 1970s, Asian carp escaped fish farms in the south, decimated bass populations, and now threaten Lake Michigan’s $7 billion sport and commercial fishery. Over the past century, 68 percent of all fish extinctions were at least partly due to the introduction of invasive species.
But here’s an even more uncomfortable truth: Our well-intentioned attempts to restore ecosystems haven’t always yielded better results, as the greenback so poignantly demonstrates. After a 20-year effort to reintroduce the native trout to mountain lakes and streams, biologists discovered they had stocked the wrong fish.
Still, in phase one of a colossal-do over, this summer, Colorado Parks and Wildlife will transfer some of Bear Creek’s 5,000 captive-bred progeny into select high alpine lakes. If they succeed, it’s validation that modern science is a more reliable shepherd than the well-intended guesswork that’s guided species conservation over the past 50 years.
J.C. Jones envisioned more than a humble cabin on his 1873 homestead along Bear Creek. The pioneer planned a hotel for Pikes Peak Highway tourists. His grand vision called for fish, either for guest suppers or sporting pleasure. So Jones collected trout from a nearby hatchery in a cream can, dumped them into the stream—and unwittingly saved greenback cutthroats from annihilation. Downstream waterfalls prevented rainbow trout from hybridizing with Jones’s fish. The greenbacks remained genetically intact, even as their kin were declared extinct in 1937.
Throughout the 1950s, reports along Colorado’s Front Range hinted that greenbacks persisted in a few remote lakes and streams. But rampant stocking during settlement made it impossible to know what species belonged where. Because the apparent
greenbacks turned up in high-altitude, backcountry waters, biologists concluded that the fish must be natives. Shortly after the greenback’s inclusion on the Endangered Species List in 1978, Colorado launched an effort to restore them to Front Range waters.
Culturists bred those fish in hatcheries to create brood stock. Trout Unlimited rallied its members to support the reintroduction— even though the native fish rarely grows to more than eight inches. Volunteer crews poisoned lakes to prepare for the greenback’s arrival. They hauled plastic jugs of fish into Rocky Mountain National Park and lakes near Cameron Pass at 10,276 feet and Guanella Passes at 11,670 feet, built barriers to keep invasive species from swimming upstream, and monitored populations.
By 2007, land managers had introduced the so-called greenback into 58 Colorado lakes and streams, establishing 20 self-sustaining populations. Officials went so far as to file the paperwork to delist the species. “That doesn’t happen often,” says Doug Krieger, a Colorado Parks and Wildlife aquatic biologist who spent 30 years reintroducing greenback cutthroats. “Success stories are hard to come by.”
But the greenback’s success story would have to wait. In 2007, University of Colorado Boulder researchers published a study that teased apart the genetic differences between the greenback and the Colorado River cutthroat. The two species look so similar that biologists hadn’t been able to distinguish between the two, although they now know the Colorado River lineage has more speckles and a pinker belly. The science demonstrated just how pervasive stocking had been and how tangled the lineage of the two species had become. It also detonated 20 years of work by the recovery team. Those 58 lakes and streams had been reintroduced with Colorado River cutthroats, not greenbacks. “Whoops!” giggled headlines from NBC to Wired. Commentators ruminated on the dubious ability of humans to fix the ecological jumble left. In fishing and land management circles, it was a scandal. “I didn’t realize people would care that much about trout,” says Jessica Metcalf, PhD, the study’s lead researcher.
Metcalf’s study inspired more research. Chris Kennedy, a biologist with the U.S. Fish and Wildlife Service, dove into reams of state, federal, and private hatchery stocking archives. His five-year investigation tracked species across the state, uncovered J.C. Jones’s part in establishing the Bear Creek population, and gave conservationists a clearer picture of Colorado’s pre-settlement landscape. Piggybacking on Kennedy’s work, Metcalf spearheaded a second study that further separated the real greenback DNA from its doppelgängers.
Metcalf’s studies led her to Harvard University’s collection of preserved 1870s trout specimens. As settlers ravaged the Western frontier, citizen scientists catalogued vanishing plants and animals. Greenback cutthroat trout specimens were sealed in jars and tucked away in archives for more than a century. “IThe DNA was super hammered, really challenging to work with,” says Metcalf.
In 2012, Metcalf published her findings, which confirmed that Bear Creek’s greenbacks are the very same strain that originally occupied the South Platte River drainage. The landmark conclusion gives wildlife managers confidence that, this time around, they’ll put the right fish in the correct habitat when they release Bear Creek descendants into the wild this summer. “when you can do good science, it changes your conservation goals,” says Metcalf. “With science, we’re not just guessing. We’ve seen that even reasonable assumptions can be wrong, and we don’t want every species to have to go through the convoluted path that the greenback did.”
A streamlined recovery process could appease detractors, who question the value of reinstating the greenback and other natives. Some objevt to the cost—federal and state agencies spent $396,000 on greenback restoration in 2010-11 alone. Others resent the inconvenience. Controversy ensued after conservationists called for trail diversions and closures near Bear Creek. Motorcyclists and anglers are already shut out, and the prospect of additional restrictions riled hikers and mountain bikers. More opponents object to poisoning lakes and streams with rotenone, a natural substance derived from plants, to eliminate competing species. “To save these native trout, it has to be done,” says Noah Greenwald, Endangered Species Director for the Center for Biological Diversity. “But carefully, with consideration for any other rare species that may be in the stream.”
Ultimately, conservationists argue, restoring native species sustains biodiversity. Certainly that’s true for trout. Anglers can now catch rainbows from the Rocky Mountains to New England—none of which represents their native Pacific basin habitat. “By destroying what’s unique and beautiful, we make things the same everywhere you go,” says Greenwald. “that homogeneity takes some of the joy and mystery out of the world.”
Leadville National Fish Hatchery attracts 50,000 annual visitors. But I’m not here to admire historic red sandstone or parquet floors. I’ve come to meet hatchery manager Ed Stege and the greenback cutthroat trout under his care.
This same hatchery once bred many of the rainbow and brown trout that decimated native stocks worldwide. Now Leadville is dedicated to one native’s rescue: Leadville’s tanks hold 550 adult greenbacks. “We’re not rearing any other species in the hatchery building,” says Stege. “I don’t want to risk of having rainbows or anything else contaminate our cutthroat stock.”
Bona fide, genetically pure greenbacks swim in four long, narrow tanks partially covered by plywood to shelter reluctant captives from inquisitive eyes. Stege explains that wild greenbacks don’t like commercial fish food when first going on feed. As fry, they were dying off in alarming numbers. “So I went old-school on ’em,” Stege says. “I bought some frozen beef liver, stole my wife’s cheese grater, and fed them like that.” Mortality went from several hundred fish a day to about 10 per day.
This summer, the greenbacks will relocate to a pair of Colorado lakes that will hopefully serve as natural hatcheries. Should the transplants thrive over the next few years, Colorado Parks and Wildlife will introduce more to additional lakes and streams within the South Platte drainage. Natural and constructed waterfalls will seal them off from invasive species downstream. If the plan works this time, within 10 or 15 years, Coloradoans might actually find their state fish widespread in its natural, native habitat.
Here in the hatchery, the greenbacks’ dark spines blend into the cement tank bottoms. Stege nets a pair, slips them into a bucket, and adds a powdered sedative that quiets the thrashing. He picks one up, and I admire the tangerine fins brightening a pale, speckled belly. The greenback represents a wilderness that vanished generations before I arrived in Colorado. Someday, in a graceful, pure-watered mountain stream, I’ll witness the greenback’s homecoming. That moment will be about more than fishing. It will mean a little patch of the Rockies has returned to the wild.