native trout

Volunteers hike native trout up to their new homes this summer


by Dan Omasta, Grassroots Coordinator

Just last week, over 110 volunteers and 50 agency staff contributed to the recovery of the threatened Greenback Cutthroat Trout. The excitement was thick on the morning of July 16, as a line of cars entered the Dry Gulch Trail head and officially kicked off the three-day recovery mission. Many participants were volunteering for the first time - a few were veterans from previous stocking years. Everyone who volunteers for one of these projects joins a very special family - a group of people that have carried a threatened species on their backs and prevented its extinction.

The goal of the two stocking projects in Dry Gulch (July 16) and Herman Gulch (July 17) was to release over 1,500 Greenback fingerlings into the high alpine creeks and to ensure that they were spread out in the habitat as much as possible. According to Colorado Parks and Wildlife biologists, spreading the fish out over the different stream reaches will reduce competition and ensure the highest possible chance of survival. Over the past few years of stocking, CPW has found an average of 40% survival - which is a good rate for fish in the wild. The long term goal is for these fish to reproduce naturally and not have to be stocked again.

My daughter and I enjoyed the event: lots of positive energy, happy agency reps and volunteers, a beautiful setting and an opportunity to get our hands wet in planting the fingerlings
— Eric Weissenberger, a volunteer at the Herman Gulch stocking event

“The opening remarks by the reps of the participating organizations … illustrated the complexity and cooperative nature of the effort. I was glad that my daughter was exposed to that information, as 13-year-olds need all the context they can get regarding the private and public working world and the wide variety of ways in which one can contribute and make a living,” Eric explained.

In 2018, volunteers for these same stocking locations won a Volunteer Service Award from the US Fish and Wildlife Service. These are big projects that demand boots on the ground. We could not do this without the hundreds of volunteers and supporters, and we know that our agency partners are very grateful as well.

Plenty of agencies, non-profits and businesses also helped make it happen, and all deserve recognition, including Colorado Parks and Wildlife, Colorado Trout Unlimited, U.S. Fish and Wildlife Service, US Forest Service, Bureau of Land Management, various TU chapters, Rep Your Water, Upslope Brewing, Basin + Bend, and Western Native Trout Initiative.

Bianca, CTU VISTA Youth Coordinator, participated in the Herman Gulch stocking and snapped some great pictures! She also took the great shots of the beaver dam removal project below.


On July 18, several volunteers worked alongside CPW and USFS staff to temporarily remove beaver dams along Black Canyon Creek. This effort is part of the larger Rock Creek Greenback Reclamation project which aims to provide another 9 miles of interconnected habitat once completed (likely in 2023). By notching the dams, CPW will be able to more effectively remove non-native brook trout from the area - which will also help treat the system for whirling disease.

Thank you to the volunteers, organizations, agencies, donors, and businesses that support the restoration of native trout populations and habitat across Colorado.

Fishing for Fahrenheit

Guy Turenne and Phil Wright trekking through deep snow to find a buried stream temperature probe on Fall Creek. Photo Credit: Phil Wright, 2019.

Guy Turenne and Phil Wright trekking through deep snow to find a buried stream temperature probe on Fall Creek. Photo Credit: Phil Wright, 2019.

It was a beautiful November day in the high country, as Guy Turenne and Phil Wright climbed their way over drifts of fresh snow along Fall Creek – a tiny tributary in the heart of Colorado’s northern mountains. 

This time, it was not fish that they were after, but a small temperature probe the size of a silver dollar, lying in wait at the bottom of the stream channel.  Months earlier, Guy and Phil, along with dozens of other TU volunteers, worked with the U.S. Forest Service (USFS) and Colorado Parks and Wildlife (CPW) to place these loggers in different stream locations throughout the eastern half of the state.

May 22 2018 Drough Map.png

Fish are heavily affected by temperature – especially trout.  Changes in thermal regimes over the course of a few hours to a few months can trigger fish to spawn, eat, grow, and even breathe.  We all saw stories in the hot, dry summer months of 2018, when low flows and extreme ambient air temperatures brought some rivers to over 79°F.  At that point, dissolved oxygen becomes increasingly scarce and fish can die. 

Stream temperatures also impact the normal day-to-day and cyclic activities of our trout.  For example, Rainbow trout will spawn in the spring when water temperature begins to rise and reaches 45-56 degrees F (52°F is ideal).  Conversely, Brown trout will spawn in the fall as water temperatures drop within 44-48°F.  Each species of trout thrives at different conditions.

So, what does any of this have to do with two TU volunteers hiking through two feet of snow in the middle of Winter?

As it turns out – a lot!  Just as water temperature affects the spawning cycle of Rainbows and Browns, thermal regimes play an important role in the development of Cutthroat trout – in this case, Greenbacks and Rio Grandes.  These fish have evolved over thousands of years to eat, grow, and reproduce at specific thermal conditions in Colorado’s Rocky Mountains.  As Trout Unlimited and native trout recovery partners continue to engage in projects that reclaim habitat and stock native fingerlings, we must ensure that the temperature regimes will support those fish long term.

But collecting that level of data across thousands of miles of small tributaries and remote drainages can pose a challenge to recovery partners.  Fortunately, TU volunteers came to the rescue.

Chris Carroll, aquatic biologist with the U.S. Forest Service teaches TU volunteers how to attach stream temperature probes during April 2018 training.

Chris Carroll, aquatic biologist with the U.S. Forest Service teaches TU volunteers how to attach stream temperature probes during April 2018 training.

With critical funding supplied by the Western Native Trout Initiative (WNTI) and the U.S. Forest Service, volunteers from several chapters helped to identify future habitat for the returning Greenback and Rio Grande Cutthroat.  In the Spring of 2018, the project kicked off with a USFS-led volunteer training during the annual CTU Rendezvous in Keystone.  From that point, chapter representatives recruited and trained their own local group of temperature probe deployment experts. Over the course of the summer, TU volunteers exceeded the original 30-site goal by setting and maintaining over 40 HOBO stream temperature loggers in several key drainages that have potential for recovery sites.

Evergreen TU volunteer, Mike Goldblatt, points to a recently-installed stream temperature probe in the Bear Creek drainage.

“We observed that the RMF membership and other members of the community seem to value stream monitoring efforts in general, are strongly supportive of such efforts, and are willing to volunteer,” explained Phil Wright, project coordinator for the Rocky Mountain Flycasters Chapter. 

As the leaves changed and fell from the trees, TU volunteers went back into the field to collect the data – which was then transferred to biologists at USFS and CPW.  From there, recovery partners will be able to show a better picture of which watersheds will make good candidates for future reintroduction. 

Trout Unlimited volunteers continue to help advance native trout recovery throughout Colorado each year – even winning a regional volunteer service award from the U.S. Fish and Wildlife Service in 2018.  Whether its notching beaver dams, backpacking in fingerlings, or tramping through two feet of powder, TU volunteers are committed and engaged in the recovery of our native trout.  The stream temperature study is another chapter of this important saga – and one that will undoubtedly be the preface for the next wave of native cutthroat recovery sites.  Who knows… maybe one of those streams will be in your backyard!

Colorado Trout Unlimited would like to recognize our valuable partners and chapters who have made this project possible:

Western Native Trout Initiative, the U.S. Forest Service, National Park Service, U.S. Fish and Wildlife Service, Colorado Parks and Wildlife, and Evergreen TU, West Denver TU, Rocky Mountain Flycasters TU, Alpine Anglers TU, Cutthroat Chapter TU, Pikes Peak TU, San Luis Valley TU, and Boulder Flycasters TU.

If you are interested to learn more about this project or volunteer, please visit Colorado TU’s Native Trout Page.

VIDEO: Reintroduction of Native Greenback Trout in Estes Park, CO


Join Alpine Anglers Trout Unlimited Chapter as they head out to the Big Thompson for a day of fishing. Learn about the important work going on in the area in regards to habitat restoration to help with the reintroduction of native Greenback Cutthroat Trout. Check out the great video below and learn more about what the chapter is doing here.

Learn about fishing the Big Thompson and other waters surrounding Estes Park, Colorado, along with the reintroduction of the Greenback Cutthroat Trout.