Rocky Mountain Sculpin - Cottus bondi
FWP Conservation Tier
The Rocky Mountian sculpin is a species that was previously known as the mottled sculpin (Cottus bairdi) in Montana, but recent genetic work has proven that the mottled sculpin doesn't exist this far east and the "mottled" sculpin in MT is more closely related to the sculpins of Russia than to the eastern US. Cottus bondi has been described from British Columbia with similar relatives in Alberta and likely Idaho. This species is highly camoflaged with it's surroundings as it blends in with the rocks (see picture). The Rocky Mountian sculpin is a native fish, widespread in Montana in mountain streams east and west of the Continental Divide. 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.
The back and sides are slate to brown with mottling and dark blotches. They may have two or three dark saddles under the second dorsal fin. The underside is whitish. The first dorsal fin is fringed with orange or red on breeding males. Palatine teeth are present.
Summary of Observations Submitted for Montana
Number of Observations:
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(Records associated with a range of dates are excluded from time charts)
They prefer riffle and run areas of fast to moderately-flowing streams that are clear and have cobble to gravelly benthic substrates.
Their diet includes a variety of immature aquatic organisms, but midge and caddis larvae are by far the most important. A study in southwest Montana showed bottom-dwelling aquatic insects comprising 99.7% of the diet.
The species serves as a forage fish for predators, often trout.
They are sexually mature in 2 years. Spawning occurs in May-June. The eggs hatch in 20-30 days at 50-60 degrees F. A southwest Montana study showed spawning throughout the month of June.