Creating a High-Elevation Refuge for Bonneville Cutthroat Trout

First published in The Midden*, Great Basin National Park's newsletter, Vol. 20, No. 2, Winter 2020. By Jonathan Reynolds, fish biologist.*

The park's fish crew and the Back Country Horsemen released 55 Bonneville cutthroat trout into Johnson Lake in September 2020. NPS photo by Julie Long.

In March 2020 Great Basin National Park began a project to create two new conservation populations of Bonneville cutthroat trout (Oncorhynchus clarkii utah, BCT) in Baker and Johnson lakes. The park hopes the two high lakes will be a refuge for the fish as the climate keeps changing.

Why high lakes

Apart from invasion by non-native fish, the three most serious threats to the park's BCT are drought, rising temperatures and catastrophic wildfire. The lakes help on all three:

• At more than 10,500 feet, they are cooler and wetter than streams thousands of feet below.
• Near the tree line, they are much less likely to be harmed by wildfire than any one of the BCT streams.

Getting Johnson Lake ready

The first year's main goal was to bring BCT to Johnson Lake, which took several steps:

1. A YSI sonde was installed to log water temperature, pH and conductivity every hour for several months.
2. Gill nets confirmed the lake had no fish.
3. Gravel from Snake Creek was hauled up and laid at the mouth of a small spring channel on the southwest shore. Trout eggs need cool, well-oxygenated water flowing through clean gravel, and the hope is that the spring will keep enough water moving for the fish to spawn and reproduce.

The NPS fish crew collecting BCT at Hendry's Creek. NPS photo by Joey Danielson.

The move

Once summer temperatures began to fall, the park and the Nevada Department of Wildlife collected BCT from Hendry's Creek in the nearby North Snake Range.

The Back Country Horsemen of Nevada, High Desert Chapter, volunteered the horses, mules and people to carry up to six containers of fish. On September 23, nine volunteers, nine horses and three pack mules took 55 BCT 3.8 miles and 2,500 feet up from the Snake Creek Trailhead to their new home in Johnson Lake.

A Back Country Horsemen mule carrying two aerated containers of BCT. NPS photo by Meg Horner.

The fish could not have been collected and moved without the Nevada Department of Wildlife and the Back Country Horsemen. Besides a successful move, the project built a new partnership, and the park looks forward to working more closely with both.

Sources

• National Park Service, Great Basin National Park, "Creating a Refugium of Bonneville Cutthroat Trout," The Midden, Vol. 20, No. 2, Winter 2020. https://www.nps.gov/articles/000/creating-a-refugium-of-bonneville-cutthroat-trout.htm
• Rewritten in hubnx's own words.