Cutthroat Trout

The Cutthroat Trout is a highly variable native trout of western North America, comprising numerous recognized subspecies adapted to specific river drainages, from coastal sea-run forms to isolated interior populations in the Rocky Mountains and Great Basin. It belongs to the genus Oncorhynchus, closely related to Pacific salmon and Rainbow Trout, with which it readily hybridizes where ranges overlap. Several subspecies, including the Lahontan and Greenback Cutthroat, are of significant conservation concern due to habitat loss, competition, and hybridization, and are protected under state and federal programs. The species is an important indicator of cold, clean freshwater ecosystem health throughout its historic range.

Cutthroat Trout are identified by the bright red, orange, or yellow-orange slash mark on the underside of the lower jaw, from which the species gets its name. Body coloration ranges widely among subspecies from silvery to deep golden or coppery, typically overlain with black spots concentrated toward the tail and dorsal areas.

• Diagnostic throat slash mark (may be faint in juveniles)
• Basibranchial teeth present at the base of the tongue
• Spotting pattern denser near the tail than the head

Cutthroat Trout are best distinguished from Rainbow Trout by the throat slash and generally less pink lateral banding, though hybrids ('cutbows') can blend both traits.

Cutthroat Trout occupy cold, clear, well-oxygenated streams, rivers, and high-elevation lakes throughout western North America, with subspecies ranges extending from coastal Alaska and British Columbia south through California and inland to the Rocky Mountains and Great Basin. Sea-run coastal cutthroat migrate between freshwater streams and nearshore marine or estuarine waters, while inland subspecies remain entirely freshwater, often isolated in headwater streams above natural barriers. They require cold water generally below 20°C, clean gravel substrates for spawning, and healthy riparian cover. Many interior populations persist only in small, fragmented headwater habitats due to historical range contraction.

Cutthroat Trout are opportunistic feeders, primarily consuming aquatic and terrestrial insects, with larger individuals and sea-run forms also taking small fish and crustaceans. They spawn in spring in gravel-bottomed streams, with females excavating redds and depositing eggs that are fertilized and left to incubate in the substrate without parental care. Some coastal populations are anadromous, migrating to saltwater or brackish estuaries to feed before returning to natal streams to spawn, sometimes repeating this cycle over multiple years unlike Pacific salmon. Cutthroat Trout play an important ecological role as both predator and prey within cold-water stream and lake food webs across their native range.