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Montana Field Guide

Montana Field Guides

Clark Fork Sculpin - Cottus sp. 10

Global Rank: GNR
State Rank: SNR
* (see State Rank Reason below)

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State Rank Reason (see State Rank above)
Not ranked yet, but will probably rank a S1 or S2 and become a species of conservation concern given it's presumed endemism to one watershed in western MT.
General Description
The St. Regis sculpin is a new sculpin species in Montana within the old Cottus confusus group. This determination is based on recent genetic work by the USFS and MTFWP. This sculpin is a very distinct species by genetic distance, but more closely resembles the slimy sculpin. It seems restricted to the St. Regis River of far western MT which lends further evidence that the Northern Rocky Mountain Refugium area of this MT/ID border region contains the most endemic species of any other area in the state. Like all sculpins, this species is a benthic invertivore meaning it eats primarily aquatic insects. They occasionally eat small fish or trout eggs but this is not a large part of their diet.

Species Range
Montana Range

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Range Comments
This newly identified species appears to be limited to the St. Regis River, a tributary to the Clark Fork River in far western Montana.

They prefer riffle and run areas of fast to moderately-flowing streams that are clear and have cobble to gravelly benthic substrates.

Food Habits
Like most sculpins, their diet probably includes a variety of larval aquatic organisms. A study in southwest Montana showed bottom-dwelling aquatic insects comprising 99.7% of the Rocky Mountian sculpin diet.

The species serves as a forage fish for predators, often brown or bull trout.

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Citation for data on this website:
Clark Fork Sculpin — Cottus sp. 10.  Montana Field Guide.  .  Retrieved on , from