Bonneville Cutthroat Trout Restoration Success

Fishing Regulations Nevada Freshwater Fishing

Approximately 14,000 years ago, prehistoric Lake Bonneville covered much of northern and western Utah, reaching into extreme eastern Nevada near Wendover and Ely. As the lake receded into what is now the Great Salt Lake and Utah Lake, streams left behind on the eastern slope of the Snake Mountain Range east of Ely became home to Bonneville cutthroat trout (BCT), one of three cutthroat trout subspecies native to Nevada. By the middle of the 20th Century, BCT had disappeared from most of its natural range in Nevada.

“In the mid-50’s there were only two intact populations of BCT, Pine Creek and Hendry’s Creek above a natural fish barrier,” says Chris Crookshanks, NDOW Native Fish Staff Biologist.

Around 1960, BCT were stocked in Goshute Creek, which is in Steptoe Valley and not part of their historic range. Goshute Creek was devoid of fish and the intent at the time was to establish a conservation population so if a catastrophic event occurred in the two creeks that still held fish, there would be a population available for restoration.

“30 years ago,” explains Heath Korell, NDOW Fisheries Biologist, “Nevada Department of Wildlife began working progressively with Utah, Idaho and Wyoming to conserve native trout populations (cutthroat) in the West.”

According to Korell, the historic range for BCT in Nevada was limited to 12 streams in the north and south Snake Range and most were devoid of intact populations of pure BCT when the states came together to work towards native trout conservation.

NDOW began developing a BCT recovery program in the late 1980’s with the goal of re-establishing populations of native BCT into all 12 streams in the north and south Snake Range which made up the historic range for the fish in Nevada.

The first step was to identify which streams held pure populations of BCT. One of the factors in the disappearance of BCT was the introduction of nonnative trout species such as brook, brown, and rainbow trout. In many cases rainbow trout interbred with the native BCT, diluting the genetics of the species. Crews spent the short summer field seasons surveying creeks to determine which held intact populations of BCT.

Genetically pure strains of BCT were found in four streams including Pine Creek, upper Hendry’s Creek, Hampton Creek (which had been stocked with Pine Creek fish) and the out of basin Goshute Creek.

The next step was to eradicate nonnative trout in the streams that didn’t hold BCT. This was done by chemically treating the streams with Rotenone, a naturally occurring compound found in the roots, seeds and stems of plants such as jicama and is widely used as both an insecticide and piscicide for killing fish. Drip stations are set up along the waterway and sprayers and sand “bombs” infused with powdered rotenone are used to treat springs and backwaters.

Once non-native species are eradicated, the streams are allowed to rest for a minimum of a year and often for several to make sure all of the non-desirable fish have been removed. The streams are again surveyed with electroshockers during the summer to confirm the absence of fish. BCT are then transferred from existing populations to the treated streams. In the late 1990’s and early 2000’s Great Basin National Park joined the effort and streams within the Park boundaries were treated and BCT were re-introduced there as well.

Korell states, “Unfortunately, there have been some setbacks. Fires have burned on Strawberry, Hampton and Goshute Creeks. The fire at Hampton was catastrophic killing all of the BCT there. The Strawberry Fire killed many of the fish in Strawberry Creek and the status of Goshute Creek is unknown at this time as the fire occurred late summer of 2018.”

Korell and Crookshanks say that as the riparian vegetation recovers along Strawberry Creek, remaining BCT should expand down the stream. When the riparian vegetation along Hampton recovers BCT may be re-introduced into that watershed as well.

“Overall, the Bonneville cutthroat trout restoration program is a huge success,” adds Crookshanks, “30 years ago we had just four intact populations, two of them outside of their historic range. We were able to establish intact populations of native BCT in all 12 streams within their historic range, and three streams outside of it.”

The Pine Creek BCT Theory

Pine Creek, on the west side of Wheeler Peak and outside of the Bonneville Basin has a BCT population whose source of fish is unknown. The accepted theory is that they got there through the Osceola Ditch that was dug by miners to bring water from the east side of the mountain to the mining district on the west side which was dry. When the ditch was abandoned and dried up, the fish were trapped on the west side in Pine and Ridge Creeks. The population of BCT in Pine Creek were then used to help stock several creeks in the basin as well as Goshute Creek which is also outside of the Bonneville Basin.