Colorado River Cutthroat Trout

Colorado River cutthroat trout have a bright yellow-gold body with a brassy-green back and orange belly, medium to large spots concentrated on the caudal peduncle and dorsal region (though spotting varies by region) and absent on the pectoral, pelvic, and anal fins, and 180-200 lateral line scales.

About This Species

Colorado River cutthroat trout, Oncorhynchus clarkii pleuriticus, are one of three recognized subspecies of native trout found in Colorado. They historically occupied portions of the Colorado River drainage in Wyoming, Colorado and Utah. Widespread introductions of non-native salmonids over the last century have served to limit current distributions primarily to isolated headwater streams and lakes. As such, the Colorado River cutthroat trout is designated as a species of special concern in Colorado, and significant resources have been dedicated to conservation of the subspecies.

Researching and Protecting Cutthroat Trout

There are four native subspecies of cutthroat trout in Colorado: the Colorado River Cutthroat, the Rio Grande Cutthroat, the Snake River Cutthroat and the native Greenback Cutthroat trout. Colorado researchers are also currently attempting to find the thought-extinct Yellowfin Cutthroat trout. All subspecies of cutthroat trout are the subject of conservation efforts and research by multiple state and federal agencies.

Conservation

Cutthroat Trout Taxonomy Research

Genetic research led by University of Colorado scientists has produced several fascinating discoveries about Colorado's native cutthroat trout - including the location of the last surviving wild population of the federally protected greenback cutthroat trout.

Researchers analyzed DNA extracted from wild trout and from museum specimens collected from sites around Colorado and New Mexico as far back as 1856, then used that genetic data as a baseline for understanding the current distribution of Colorado's native cutthroat trout.

In addition to identifying the one remaining "true" greenback population, researchers identified two distinct genetic lineages within the range of Colorado River cutthroat trout, one in northwest Colorado and the other centered around the Gunnison River basin. Further research will be needed to understand the relationship between these two lineages.

In all, six lineages of cutthroat appear to have evolved in Colorado, with native ranges that roughly correspond to major drainage basins in the state. The greenback cutthroat trout, Colorado's state fish, was native to the drainages of the South Platte, while the long extinct yellowfin cutthroat trout of Twin Lakes actually appears to have been the native trout of the Arkansas River Basin. Rio Grande cutthroat trout still can be found in streams that drain into the San Luis Valley, while a lineage that used to call the San Juan basin home appears to be extinct as well. More research will be required to resolve whether the remaining two lineages that can be found across Colorado’s western slope are indeed two distinct subspecies – that work is ongoing.

Given that additional lineages of our native cutthroat trout were identified with the DNA testing, we wanted to determine if these lineages displayed different physical characteristics as well. This is particularly important since it has been argued that genetics should not be the sole factor in determining taxonomic distinctions, and that morphological traits (visual characteristics) are often better suited for discriminating taxa. A recent comprehensive study examined the relationship between the differences implied by the DNA and the morphology of these fish. Indeed, it appears that these new lineages can also be identified by examining morphological traits as well.

Wild Spawn Operations

Cutthroat Trout in a Changing Climate

Securing Native Cutthroat Trout in Trappers Lake, Colorado

Species Type

Fish

Scientific Name

Oncorhynchus clarkii pleuriticus

Protection Status

State Special Concern