Cutthroat Trout (Onchorhynchus clarki)
Our research focuses on characterizing the genetic variation and inferring the historical biogeography of Colorado's native cutthroat trout based on analysis of mitochondrial and nuclear DNA from contemporary and historic samples from museums. In particular, we are interested in assessing the number of distinct subspecies and whether currently identified populations of particular subspecies are native, originated by introduction from trout stocking programs over the last century or more, or are descended from mixed stocks resulting from past stocking and subsequent hybridization.
Recent discoveries
Evaluating the success of conservation efforts
Restoration efforts for recovering the greenback cutthroat trout (GCT) in Front Range streams were compromised by inadequate genetic assessments of broodstock used for propagation and stocking. In particular, broodstock was derived from either pure Colorado River cutthroat trout (CRCT) or trout of mixed GCT x CRCT ancestry. This work was highlighted in scientific journals and the popular press, including Science, Nature, ESPN, Fox News, CNN, NYTimes, and several local or regional news agencies.
Rocky Mountain National Park (RMNP) was the site of intensive restoration of GCT. Our genetic assessment of the trout populations of RMNP suggest that most populations show evidence of mixed ancestry: only a handful of putatively pure populations were discovered. Additionally, some population showed evidence of four different subspecies of cutthroat trout, suggesting that restoration efforts did not erase the genetic legacy of earlier management efforts.
Effects of introducing rainbow trout
Introduced rainbow trout readily hybridize with cutthroat trout wherever the two species come into contact, and that the result is a hybrid swarm. One consequence of hybridization is the irreversible loss of the native trout gene pool.