Cutthroat Trout / Subspecies / Southern Rocky Mountains
The Colorado River cutthroat trout (Oncorhynchus clarki pleuriticus) is a subspecies of cutthroat trout native only to the Green and Colorado River basins, which are west of the Continental Divide. Cutthroat trout found in other river basins belong to other subspecies.
Image credit: Fremont River Guides
The greenback cutthroat trout (Oncorhynchus clarkii stomias) is the easternmost subspecies of cutthroat trout. The greenback cutthroat, once widespread in the Arkansas and South Platte River drainages of Eastern Colorado and Southeast Wyoming, today occupies less than 1% of its historical range. It is currently listed as threatened under the Endangered Species Act. It was adopted as the state fish of Colorado on March 15, 1994 replacing the unofficial rainbow trout. In 2012, a genetic study that compared DNA samples both from modern populations and historical samples dating back to the 19th century revealed that the only remaining population of pure greenback cutthroat trout is found in a 4-mile (6.4 km) stretch of Bear Creek, a tributary of the Arkansas River. Many of the populations previously identified as greenback cutthroat were actually of the similar Colorado River and Rio Grande cutthroat subspecies.
Image Credit: Central Alberta Fly Tying Club
It is one of 14 subspecies of cutthroat trout native to the western United States, and is the state fish of New Mexico. Cutthroat trout were the first New World trout encountered by Europeans when in 1541, Spanish explorer Francisco de Coronado recorded seeing trout in the Pecos River near Santa Fe, New Mexico. These were most likely Rio Grande cutthroat trout
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