The Greenback Trout

The greenback cutthroat Salmo clarki stomias is a variety native to the Arkansas and South Platte river drainage basins of Colorado. When the first white settlers arrived in this region the greenback was apparently abundant. However, water abstraction and diversion of streams for irrigation, pollution from mining spoil, and overfishing decimated the stocks. Then the European brown trout and the American speckled char were introduced, followed by rainbow trout and other forms of cutthroat. These ousted many of the native greenbacks by competition, and interbred with the remaining population producing hybrid stocks.

In Cutthroat, Patrick Trotter records that, though the strain was considered extinct by 1937, thorough surveys made in the 1960s discovered two relict pure greenback populations: one in a tributary of North Boulder Creek and the other in the headwaters of South Poudre River. Elsewhere, hybrid cutthroat stocks still exhibit some of the characteristics of the greenback.

This variety of cutthroat is on the lists of endangered species of the 1973 US Endangered Species Act and the State of Colorado list of 1976. Big efforts are being made to rear pure greenbacks in captivity and then release them into their former range; and at the same time to remove the non-native trout. As a result, the survival of one form of wild trout, that was on the verge of extinction, at last seems assured.