© Joseph Dougherty. All rights reserved.
Oncorhynchus clarkii (J. Richardson, 1836)
Throughout their native and introduced range, cutthroat trout vary widely in size, coloration, and habitat selection. Though their coloration can range from golden to gray to green on the back, and depending on subspecies strain and habitat, they usually feature distinctive red, pink, or orange linear marks along the underside of the mandible in the lower folds of the gill plates; the easiest diagnostic of the species for the casual observer. These markings are responsible for the formation of the typical name "cutthroat". At maturity, different populations and subspecies of cutthroat can range from 6–40 inches (15–100 cm) in length, depending on habitat and food availability, making size an ineffective indicator as to species identity. Cutthroat are typically prized as a sportfish, particularly by fly anglers, as their propensity to inhabit remote waters and diminutive streams appeals to the sense of adventure present in many outdoor enthusiasts. In addition, their tendency to exhibit significant activity and resistance to anglers in conjunction with this species' affinity for terrestrial or mature insects serves to increase popularity of the cutthroat as an angler's quarry. Finally, the cutthroat participates in a unique predator-prey relationship with the bull trout that is key to ecosystem integrity across much of its natural range.