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Aquatic Sciences Laboratory - Species Profiles

Snake River Finespotted Cutthroat Trout
Oncorhynchus clarki behnki
(Jackson Hole Cutthroat Trout)

Snake River finespotted cutthroat trout are a native species whose current distribution ranges from Palisades Reservoir to Jackson Lake on the Snake River mainstem, as well as various tributaries therein. However, historical stocking of rainbow trout, as well as Snake River and Yellowstone cutthroat trout, has made it difficult to ascertain the actual historical native range of this subspecies. The main external distinction in comparison to other cutthroat trout is the small “pepper flake” spots that are densely scattered across the body. Interestingly, this subspecies was given its official scientific name “behnki” with publication of Robert Behnke’s monograph “Native Trout of Western North America” in 1992. Also, finespotted cutthroats are the only extant cutthroat trout whose range overlaps with another cutthroat, Yellowstone cutthroat trout. While their ranges overlap, the two closely related subspecies do not occur in the same areas within that range, and have remained separate subspecies rather than hybridizing into a new species.

Behnke stated in his 1992 description that it “is the only subspecies of cutthroat trout more abundant now than it was historically,” mostly due to heavy stocking both within and outside of its native range. Snake River finespotted cutthroat trout evolved with a variety of fish species, including a similar trout subspecies, helping it to be adaptable in relation to stocking programs. While pollution of the gene pool has occurred in some populations, this subspecies of cutthroat resists hybridization with other trout, but it should be noted that hybrids with rainbow trout have occurred in Idaho.

References:

Behnke, R.J. 1992. Native Trout of Western North America. American Fisheries
Society Monograph 6.
Behnke, R.J. 2002. Trout and Salmon of North America. The Free Press, New York.

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