Species Profile

Mountain Sucker Pacific populations

Scientific Name: Catostomus platyrhynchus
Taxonomy Group: Fishes
Range: British Columbia
Last COSEWIC Assessment: November 2010
Last COSEWIC Designation: Special Concern
SARA Status: Schedule 1, Special Concern

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Quick Links: | Description | Habitat | Biology | Threats | Protection | Recovery Team | National Recovery Program | Documents

Image of Mountain Sucker


The Mountain Sucker (Catostomus platyrhynchus) is a small bottom-dwelling freshwater fish. Mountain Suckers have elongated cylindrical bodies. They are dark green to grey or brown with yellow to white bellies. The species has a straight, green or black lateral line along its sides. During breeding season, this line turns red and fleshy bumps develop on the surface of the body. Mountain Suckers have downward facing mouths with large upper lips covered in fleshy bumps called papillae. Typically, Mountain Suckers are between 127 to 152 millimetres. (Updated 2017/05/17)


Distribution and Population

Mountain Suckers live in freshwater habitats in the western mountainous regions and westernmost Great Plains of North America. Three designatable units exist in Canada, and represent discrete and evolutionarily significant units of the species. These are the Saskatchewan-Nelson River populations, the Milk River populations, and the Pacific populations. The Pacific populations live in British Columbia in the Similkameen River and its tributaries (Columbia River drainage), the North Thompson River, and the lower Fraser River. Population sizes are unknown at this time. (Updated 2017/05/17)



In British Columbia, Mountain Suckers are associated with cool waters, swift currents and rocky substrate. They live in small clear mountain streams, as well as larger turbid rivers. In the summer, Mountain Suckers tend to be found in deeper glides and pools. (Updated 2017/05/17)



There is limited information on the biology of Mountain Suckers in British Columbia. Across North America, Mountain Suckers spawn in late spring to early summer. Eggs are scattered over the substrate and likely hatch within two weeks. Older and larger female fish produce more eggs. Pacific populations of Mountain Suckers typically mature at four to five years old. The species feeds on plankton, small invertebrates, and organic matter that it scrapes from the surface of rocks. Mountain Suckers may be preyed on by birds, mammals, and other fishes. (Updated 2017/05/17)



Most threats to the Pacific populations of Mountain Suckers are related to habitat loss and degradation associated with agriculture, resource extraction, and commercial/industrial land use. Specific threats faced by these populations include: water availability and use; channelization; sedimentation; water impoundments and flow regulation; toxicity; aquatic invasive species; and climate change. (Updated 2017/05/17)



Federal Protection

More information about SARA, including how it protects individual species, is available in the Species at Risk Act: A Guide.

Provincial and Territorial Protection

To know if this species is protected by provincial or territorial laws, consult the provinces' and territories' websites.


Recovery Team

Pacific Region Species at Risk Program - Mountain Sucker

  • DFO Pacific Region - MPO région du Pacifique - Chair/Contact - Fisheries and Oceans Canada
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Recovery Progress and Activities

A management plan for the species will be developed, which will include measures for the conservation of the species. Recovery initiatives intended for other species with overlapping ranges, such as the Columbia Sculpin and White Sturgeon, may also provide some benefit to Mountain Sucker Pacific populations. (Updated 2017/05/17)


PLEASE NOTE: Not all COSEWIC reports are currently available on the SARA Public Registry. Most of the reports not yet available are status reports for species assessed by COSEWIC prior to May 2002. Other COSEWIC reports not yet available may include those species assessed as Extinct, Data Deficient or Not at Risk. In the meantime, they are available on request from the COSEWIC Secretariat.

5 record(s) found.

COSEWIC Status Reports

  • COSEWIC Assessment and Status Report on the Mountain Sucker Catostomus platyrhynchus in Canada (2011)

    The Mountain Sucker, also commonly known as the Northern Mountain Sucker or the Plains Sucker, is a small (usually < 250 mm fork length) bottom-oriented fish of the western mountainous regions and westernmost Great Plains of North America. The Mountain Sucker has a sub-terminal mouth with characteristic “fleshy bumps” (papillae) on the lips. The body is elongate, cylindrical and somewhat compressed caudally. Molecular genetic data and the distribution of Mountain Suckers among three National Freshwater Biogeographic Zones (NFBZ) identify three designatable units (DU) in Canada (Saskatchewan-Nelson DU, Missouri DU and Pacific DU).

Response Statements

  • Response Statement - Mountain Sucker, Pacific populations (2011)

    This small freshwater fish has a patchy distribution within the North Thompson, lower Fraser and Similkameen rivers drainages in British Columbia. It has a small area of occupancy and number of locations within each of these areas. It is likely that habitat quality will continue to decline over about 40% of its Canadian range owing to increased water extraction in the Similkameen River drainage that climate change is expected to exacerbate.


  • Order Acknowledging Receipt of the Assessments Done Pursuant to Subsection 23(1) of the Act (2016)

    His Excellency the Governor General in Council, on the recommendation of the Minister of the Environment, acknowledges receipt, on the making of this Order, of the assessments done pursuant to subsection 23(1) of the Species at Risk Act by the Committee on the Status of Endangered Wildlife in Canada (COSEWIC) with respect to the species set out in the annexed schedule.
  • Order Amending Schedule 1 to the Species at Risk Act (2017)

    His Excellency the Governor General in Council, on the recommendation of the Minister of the Environment, pursuant to subsection 27(1) of the Species at Risk Act, makes the annexed Order Amending Schedule 1 to the Species at Risk Act.

COSEWIC Annual Reports

  • COSEWIC Annual Report - 2010 - 2011 (2011)

    Under Canada’s Species at Risk Act (SARA), the foremost function of COSEWIC is to “assess the status of each wildlife species considered by COSEWIC to be at risk and, as part of the assessment, identify existing and potential threats to the species”. COSEWIC held two Wildlife Species Assessment Meetings during the past year assessing the status or reviewing the classification of a total of 92 wildlife species.