Fish Species Survives in 9... 5... 1 Stream?

Greenback Cutthroat Trout; courtesy USGS.

The greenback cutthroat trout (Oncorhynchus clarki somias) was designated as Colorado's state fish in 1994.  In the years since, this endangered native fish has come to symbolize some of the major struggles inherent in the conservation of various fish species throughout the Colorado River basin.  The greenback cutthroat trout, a relatively small fish that grows to be an average of 38 centimeters long, is assumed to have originated in "all mountain and foothill habitats of the South Platte and Arkansas river drainage systems."  Today, there is a complicated debate over where it actually still exists that brings into question both scientific information and human values.

On September 25, 2012, the New York Times ran an article entitled, "Rare Trout Survives in Just One Stream, DNA Reveals."  Based on a study by post-doctoral researcher Jessica Metcalf that was published in Molecular Ecology, the article explained how after "analyzing DNA sampled from cutthroat trout specimens pickled in ethanol for 150 years, comparing it with the genes of today’s cutthroat populations, and cross-referencing more than 40,000 historic stocking records," researchers discovered that there was only one wild population of greenback cutthroat left.  This research is being replicated by a second group to verify the results.

Courtesy Rocky Mountain Field Institute.

This remaining population of greenback cutthroat trout lives in Bear Creek, an alpine stream running from the eastern slope of Pikes Peak near Colorado Springs, CO.  Somewhat ironically, researchers believe that this specific population may have "descended from fish stocked at the Bear Creek headwaters in the 1880’s by a hotelier seeking to promote a tourist route up Pikes Peak."  If this is truly the case, the only existing population of this species was not saved by conservationists at all, but rather by citizens seeking to derive economic benefits.


Aside from the shock of discovering that only a single population of an endangered species exists, the findings were particularly surprising in light of the controversy surrounding recent conservation efforts of the species.  While the fish was thought to have gone extinct in 1937, researchers in the 1950's claimed that "remnant populations were found in tributaries."  After the fish was added to the endangered species list in the 1969, biologists used these populations to breed additional greenback cutthroat trout in hatcheries and propagate them into new waters.

However, in 2007, a three-year study done in part by University of Colorado researchers claimed that "out of nine fish populations believed to be descendants of original greenbacks, five were actually Colorado River cutthroat trout."  This second species of cutthroat trout is extremely similar to the greenback cutthroat, both to the naked eye and to early scientific tests, but actually has a distinct genetic line.  The Colorado River cutthroat trout, native to streams West of the Continental Divide, that were stocked into habitats with the greenback cutthroat trout may have actually out-competed the fish that researchers were attempting to save.

Courtesy New York Times.

In fact, there are fourteen subspecies of cutthroat trout, four of which have been found in Colorado.  However, it appears that humans have been stocking these different trout populations into various streams since the mid-1880's.  Although species have been transplanted outside of their native range, many have thrived and contributed to functional ecosystems.  Now, the population from Bear Creek is being bred and stocked in other locations.  In addition, just a few days before the newest study was released, the Center for Biological Diversity filed a Suit to Protect Rare Greenback Cutthroat Trout from the pollution and other habitat destruction caused by the use of off-road vehicles near Bear Creek.  Issues including "sedimentation and erosion impacts from 3.9 miles of the Pike National Forest system trail #667 which runs adjacent to upper Bear Creek" are already being managed to improve the trout's habitat.  Obviously, this new flood of information has raised the stakes of the suit.

Greenback Cutthroat Native Habitat Map; Courtesy USGS.

Jessica Metcalf, lead researcher on the newest study, acknowledges the irony of the situation:  “It’s ironic that stocking nearly drove the greenback cutthroat trout to extinction, and a particularly early stocking event actually saved it from extinction."  This issue seems to symbolize some major conservation conflicts and questions, especially for the unique Colorado River region:  should species be stocked into habitats where they are likely to thrive, even if those habitats are outside of their native range?  What unintended consequences--or in this case, benefits--may come from this type of management? The answers to these questions require a deeper exploration of the complex values and continuously evolving science surrounding the issues at hand.

Flooding the Colorado

2008 High-Flow Release--Glen Canyon Dam; Credit T. Ross, Bureau of Reclamation on NPT

The most recent experiment on the Colorado River shows a shift in perspective--or at least an incorporation of more diverse values--into the management of the river ecosystem as a whole.  On Monday, November 20, 2012, "The Colorado River cascaded in a flood from the Glen Canyon Dam," according to NBCNews.  This "flood" was actually an experimental release of water that had been in the works for many months prior to the event.  In fact, it was back in May 2012 that Interior Department officials finally decided that they would release water from Lake Powell down the Colorado River.

Courtesy EarthLabs.

Glen Canyon Dam is a massive 710-foot-tall structure that sits on the Colorado River right below Arizona's northern border near the town of Page.  It holds back Lake Powell's average 20+ million acre feet (maf) storage of water and generates hydroelectric power by means of eight turbines.  This is the largest volume of storage on the Colorado River, an element which has become essential to meeting the water needs of the Southwest.  However, the dam also restricts the natural seasonal flows of the river, drastically affecting the ecology of the river system and surrounding area.

Humpback chub, Courtesy Deserted Fish.

This experimental release, through both the power-generating and the bypass tubes of the dam, aims to mimic natural flows and help "rebuild high-elevation sandbars, deposit nutrients, and restore backwater channels," according to USGS.  In particular, restoring the habitat for the endangered native humpback chub is often cited as a primary goal.  The USGS website goes on to the explain that the last high-flow release in 2008 (proceeded by releases in 2004 and 1996) allowed 41,000 cubic feet per second (cfs) to flow freely down the Colorado River for about sixty hours.  This time, the flood gates were opened for five days, allowing a peak flow of 42,000 cfs to be reached for one day at the start of the experiment.  All of the specific stats on flow volumes and schedules can be found on the Bureau of Reclamation's website.

According to an article by National Parks Traveler, the 2008 release in particular was quite controversial with National Park officials, who were worried about the true purpose behind the releases.  Park Superintendent Steve Martin was particularly skeptical of the Environmental Assessment of the project, highlighting that the Bureau of Reclamation did not make the Park a cooperating agency in the process or give them proper time to comment on the plans.  Moreover, Martin was concerned with the scientific soundness of the plan, which described "steady" releases over the next five years that did not correspond with the previously established National Park management policies.  Because the water flowing down the Colorado River is such a valuable resource to all stakeholders involved, it's easy to see why Martin may have suspected that the goal of the flooding was not actually to benefit the natural resources, but instead to provide water to downstream users or benefit hydroelectric interests.  However, plans for the flooding pressed on.

Then DOI Secretary Dirk Kempthorne begins the 2008 release; Courtesy DOI.

In 2010, the US Geological Survey released an assessment of these high-flow events that claimed, "high flows through the Grand Canyon that mimic natural ebbs and flows are beneficial for the river corridor," but also noted that "many of the benefits are erased within six months due to energy demands that dictate releases through the Glen Canyon Dam."  Thus, the experiment is officially continuing (and is now slated to run on and off through 2020), but still meets some resistance.

Ken Salazar, Secretary of the Interior, has attempted to mitigate this conflict by explaining that high-flow releases that greatly benefit fish populations and improve sediment distribution can occur while simultaneously promoting other goals, such as electricity generation and water supply.  He promises further scientific assessment and increased inclusiveness of all necessary stakeholders in the process, a premise which is becoming increasingly important in policy-making endeavors throughout the American West in particular.  Additionally, although the high flows will temporarily cause some campsite closures, recreational interests are also jumping on board.  George Wendt, who serves as the president and CEO of OARS Outdoor Adventure River Specialists and a member of Protect the Flows (an organization mentioned in my earlier post on recreation), has publicly applauded the DOI for their decision to release flows that promote conservation and consequently improve the canyon for future use by boaters, rafters, and other recreators.

2012 Release from Bypass Tubes; Courtesy Bureau of Reclamation.

By including a wider variety of stakeholders--which inherently brings a breadth of new values to the table--and promising further scientific investigation into the issue, the Department of Interior seems to have made a positive step toward a more smooth and inclusive river management strategy.  Hopefully a portion of all of the diverse goals can be met:  improving ecosystems, increasing recreational activity, providing reliable hydroelectric power and water to residents, and perhaps most importantly, helping to bring various organizations together to promote sustainable future management of the Colorado River.