Creating a Refugium of Bonneville Cutthroat Trout

This article was originally published in The Midden – Great Basin National Park: Vol. 20, No. 2, Winter 2020.

The Fish Crew at GRBA teamed up with the Back Country Horsemen to successfully release 55 BCT into Johnson Lake during September 2020.

NPS Photo by Julie Long

By Jonathan Reynolds, Fish Biologist

In March 2020, a project was initiated to create two new Bonneville cutthroat trout (Oncorhynchus clarkii utah, BCT) conservation populations in Baker and Johnson Lakes. Great Basin National Park hopes that these two high elevation lakes will act as a refugia for BCT as our climate continues to change.

The three most serious threats facing the Park’s BCT populations (beside the invasion of nonnative fishes) are drought, increasing temperatures, and catastrophic wildfires. Located over 10,500 feet above sea level, Johnson and Baker Lakes experience cooler air temperatures and more precipitation than the streams located thousands of feet below. Also, since the lakes are located near the edge of the tree line, the probability of a wildfire negatively affecting the lake populations is much lower than that of a fire negatively affecting any one of the BCT streams.

NPS fish crew collecting BCT at Hendry’s Creek

NPS Photo by Joey Danielson

One of the main objectives during the first year of the project was to introduce BCT to Johnson Lake. Several steps needed to be completed before the introduction could occur. First, a YSI SONDE was installed, which measured water temperature, pH, and conductivity every hour for several months. Next, gill nets were deployed in Johnson Lake to ensure that the lake was, in fact, fishless. Lastly, gravel from Snake Creek was hauled to Johnson Lake and placed at the mouth of a small spring channel located on the southwest shoreline. Cool, high oxygenated water flowing through clean gravel is imperative for the survival of trout eggs. The hope is that the spring will provide enough flowing water through these gravels to allow the BCT to spawn and reproduce successfully.

Once everything was ready and the summertime temperatures began to decrease, Great Basin National Park partnered with Nevada Department of Wildlife (NDOW) to collect BCT from Hendry’s Creek, a stream located in the nearby North Snake Range.

A Back Country Horsemen’s mule packed with 2 aerated containers of BCT.

NPS Photo by Meg Horner

The Back Country Horsemen of Nevada - High Desert Chapter volunteered to provide the horses, mules, and personnel necessary to transport up to 6 containers of BCT to Johnson Lake. On September 23rd, nine volunteers, nine horses, and three pack mules safely escorted 55 BCT the 3.8 miles and 2,500 feet of elevation gain from the Snake Creek Trailhead to their new home in Johnson Lake.

Great Basin National Park would like to thank everyone that helped make the first year of this project a success. BCT could not have been collected and transported to Johnson Lake without collaborating with NDOW and the Back Country Horsemen of Nevada. Not only was the Johnson Lake fish move a huge success, but a new partnership was made and the Park looks forward to working with both NDOW and the Back Country Horsemen more closely in the future.

The Back Country Horsemen put together a video of the fish collecting event.