Alvord cutthroat trout were a subspecies of cutthroat trout native to the Alvord Basin of southeast Oregon that many believe went extinct in their pure form shortly after they were described. The yellowfin cutthroat trout (Oncorhynchus clarkii macdonaldi) is an extinct subspecies or variety of the cutthroat trout, a North American freshwater fish. Weighing in at 40 pounds, with stories of the trout getting up to 60, the Lahontan is the largest species of cutthroat trout. Species: Yellowfin cutthroat trout Status: Extinct (early 1900’s) What happened: A subspecies of the cutthroat trout, the yellowfin cuttie was first discovered and named in American waters back in 1891. Young cutthroat trout emerge from their eggs after two months (Elliot, 2005). A novel genetic study has helped to clarify the native diversity and distribution of cutthroat trout in Colorado, including the past and present haunts … (Behnke, 1992; Elliott, 2005) 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. The recovery of the Lahontan cutthroat trout is a true resurrection story. Cutthroat trout, first described in 1541, are widespread in inland watersheds of western North America, with at least 14 known subspecies. A unique type of trout thought to be extinct has been rescued from southwestern Colorado streams where ash from a wildfire threatened their survival. A fourth subspecies, the yellowfin cutthroat native to Arkansas River headwaters that weighed up to 10 pounds, disappeared in the early 1900s, according to the latest fish extinction research. iii ABSTRACT The range and abundance of genetically pure westslope cutthroat trout (Oncorhynchus clarkii lewisi) has greatly decreased as a result of the introduction of, and hybridization with, rainbow trout (O. mykiss).By examining the ecology, physiology and the phylogenetic relationship, “The only greenback cutthroat trout population that we have now is the one in Bear Creek,” said Jessica Metcalf, a University of Colorado post-doctoral researcher who conducted the study. Once they hatch they mature, spawn, then die. Mark Pizzimenti's recently self-published endeavor is a play on Colorado's extinct yellowfin cutthroat trout and a Wild West "fish war" on the Grand Mesa. Colorado Parks and Wildlife has found a cutthroat trout species thought to be extinct. Cutthroat trout that migrate to the sea develop for up to four years in their natal stream, then migrate into the ocean only to return 2 to 3 months later to spawn (Behnke, 1992). A fourth subspecies, the yellowfin cutthroat native to Arkansas River headwaters that weighed up to 10 pounds, disappeared in the early 1900s, according to the latest fish extinction research. In the Southern Rockies of Colorado, the prevailing view… The agency has plans to develop a strategy to reintroduce the fish in rivers throughout the region. Mark Pizzimenti's recently self-published endeavor is a play on Colorado's extinct yellowfin cutthroat trout and a Wild West "fish war" on the Grand Mesa. 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.