Fish
Cutthroat Trout
Oncorhynchus clarkii · also called cutthroat trouts
In a cold western mountain stream, a cutthroat trout holds steady against the current, the bold red slash beneath its jaw giving away its identity at a glance, a marking distinctive enough that it named an entire species spread across dozens of separate river drainages.
Overview
The cutthroat trout, Oncorhynchus clarkii, is a native trout species found in cold streams, rivers, and lakes across a broad range of western North America. Its distinctive throat marking, remarkable diversity of geographically isolated subspecies, and vulnerability to hybridisation with introduced rainbow trout make it one of the more genetically complex and conservation-significant native fish in the American West.
One species, dozens of separate stories
Rather than a single uniform population, the cutthroat trout exists as a patchwork of distinct subspecies, each shaped by its own isolated river or lake basin, giving the species a genetic diversity that mirrors the fragmented mountain geography of the American West itself.
Status
Least Concern overall, though several individual subspecies have declined significantly due to habitat degradation, hybridisation with introduced rainbow trout, and migration barriers.
Cutthroat Trout: common questions
Why is it called the cutthroat trout?
This species is named for a bold red or orange slash marking the underside of the lower jaw, a distinctive feature reminiscent of a cut throat that gives the species its common name and helps separate it visually from several other North American trout species that lack this specific marking.
Why does the cutthroat trout have so many different subspecies?
This species includes numerous distinct subspecies that developed separately across different river drainages and lake basins in western North America, isolated from one another by geography over a long period of time, resulting in a range of subtly different populations that are often managed and conserved separately due to their genetic distinctiveness.
Why is hybridisation a problem for cutthroat trout?
This species readily hybridises with introduced rainbow trout where the two species overlap, and because this genetic mixing can gradually erode the distinctiveness of native cutthroat trout populations over generations, it is considered a significant conservation concern for several cutthroat trout subspecies even where overall numbers remain relatively stable.
Does the cutthroat trout migrate?
Some populations of this species remain in freshwater their entire lives, while others are migratory, moving between smaller streams and larger lakes, or, in certain coastal populations, out to the ocean and back, a variation in life history strategy that differs between the many subspecies and populations found across its range.