Shorthead Sculpin

Illustration of shorthead sculpin, Cottus confusus, by Susan Laurie Bourque.

Reproduced courtesy of the Canadian Museum of Nature, Ottawa, Canada.

Species at Risk Act

Status: Threatened

Recovery Strategy: link

COSEWIC Summary

Date of Assessment: May 2001

Common Name: shorthead sculpin

Scientific Name: Cottus confusus

COSEWIC Status: Threatened

Reason for Designation: This species has a very small and restricted population in British Columbia. Its habitat is impacted by urban and rural development and by changes in water levels.

Canadian Occurrence: British Columbia

COSEWIC Status History: Designated Threatened in April 1984. Status re-examined and confirmed Threatened in May 2001.

Brief Description of Shorthead Sculpin and Its Habitat

Shorthead sculpin occur sympatrically or within the range of other sculpin species and can be difficult to distinguish in the field, even by trained biologists and ichthyologists. Contributing to the problem of identification, hybrids between slimy sculpin and shorthead sculpin have been found in some sites and specimens with traits intermediate between shorthead and mottled sculpin have been found in the Flathead River and Milk River drainages. Several characters are typically required to confidently identify C. confusus. Traits used to identify shorthead sculpin include fin ray counts, head papillae, lateral line and head pores, presence of prickles, and head length. Several molecular genetic markers are also effective diagnostic tools.

The shorthead sculpin occurs west of the Continental Divide, primarily in the Columbia River watershed of the western US states of Washington, Idaho, Oregon and Montana and in tributaries to Puget Sound in Washington State. The northern range limit of the species extends into southern British Columbia, in the Columbia River watershed. Surveys completed during and since the 1980s have helped to better define the distribution of shorthead sculpin in Canada. Shorthead sculpin are now confirmed present in the Slocan River, the Kettle River and the mainstem and tributaries of the Columbia River. Individuals were collected from the mainstem Slocan River, and downstream of Cascade on the Kettle River. Individuals were not found upstream of Cascade, or in the Similkameen River. Shorthead sculpin were once thought to be widespread in the Canadian portion of the Flathead River, but those fish are now considered to be a separate taxonomic entity.

In general, shorthead sculpins inhabit cold, fast riffles in streams with cobble-gravel substrates. Wydoski and Whitney (2003) suggest that preferred current velocity is 0.9 m sec^-1 or greater, although individuals occur in slower moving water along shorelines and back waters. Riffles are the preferred habitat type, though individuals may occur in a variety of habitats including riffles, runs and pools. Shorthead sculpin are most abundant in streams with cool summer temperatures —temperatures that tend to be somewhat cooler than for other sculpin species. Wydoski and Whitney (2003) suggest that preferred summer temperatures are less than 15.5 ˚C and the species observation with the highest temperature was 23.9 ˚C. As a result of habitat preferences, shorthead sculpin tend to occur at higher elevations relative to other cottids.

Some References

Hendricks, P. 1997. Status, distribution, and biology of sculpins (Cottidae) in Montana: a review. Helena, MT.

Hughes, G. W., and A. E. Peden. 1984. Life history and status of the shorthead sculpin, Cottus confusus: Pisces, Cottidae) in Canada and the sympatric relationship to the slimy sculpin (Cottus cognatus). Canadian Journal of Zoology 62:306-311.

Johnson, D. W., D. A. Cannamela, and K. W. Gasser. 1983. Food habits of the shorthead sculpin (Cottus confusus ) in the Big Lost River, Idaho. Northwest Science 57:229-233.

Maret, T. R., and D. E. MacCoy. 2002. Fish assemblages and environmental variables associated with hard-rock mining in the Coeur d’Alene river basin, Idaho. Transactions of the American Fisheries Society 131:865-884.

McPhail, J. D. 2001. Habitat use of vulnerable (Blue-listed) sculpins in the Kootenays.

McPhail, J. D. 2007. The freshwater fishes of British Columbia. University of Alberta Press, Edmonton.

Neely, D. A. 2004. Identification of problematic sculpins from Montana using mtDNA sequence data and morphology.

Peden, A. E. in press. Update COSEWIC status report on the shorthead sculpin Cottus confusus in Canada. Ottawa.

Peden, A. E., and G. W. Hughes. 1984. Status of shorthead sculpin, Cottus confusus, in the Flathead River, British Columbia. Canadian Field-Naturalist 98:127-133.

Peden, A. E., G. W. Hughes, and W. E. Roberts. 1989. Morphologically distinct populations of the shorthead sculpin, Cottus confusus, and mottled sculpin, Cottus bairdi (Pisces, Cottidae), near the western border of Canada and the United States. Canadian Journal of Zoology 67:2711-2720.

Wydoski, R. S., and R. R. Whitney. 2003. Inland fishes of Washington. Second edition. American Fisheries Society in association with University of Washington Press.

Recovery Team Documents

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