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: No schedule, No Status
Image of Mountain Sucker
The Mountain Sucker (Catostomus platyrhynchus) is a freshwater bottom-dwelling fish belonging to the family Catostomidae. They are identifiable by their elongated, dark green to grey or brown cylindrical body, with the underneath colored pale yellow to white. Blotches of black are often seen on the sides and a straight lateral line (green to black) is also present. During breeding season this line turns red and fleshy bumps on the surface of the body develop, called “nuptial tubercles.” This species’ mouth is large and ventral with a large upper lip and a lower lip shaped like paired wings. Lips are covered in fleshy bumps called papillae. Notches at the corners of the mouth and an incomplete cleft on the lower lip help to distinguish this population from most other catostomids. Mountain Suckers have a dorsal fin, caudal fin, anal fin, and two each of pectoral and pelvic fins. Adult individuals typically range from 127 to 152 mm in length.
Distribution and Population
Three designatable units (DUs; representing discrete and evolutionarily significant units of the species) exist in Canada: Saskatchewan-Nelson River populations and Milk River populations (occurring in Saskatchewan/Alberta), and Pacific populations (occurring in British Columbia). Pacific populations are found in the Similkameen River and its tributaries including the Columbia River system, North Thompson River, lower Fraser River and potentially at the confluence of the Salmo and Pend d’Oreille Rivers. Abundance estimates for Pacific populations are unknown at this time.
Little information is available on Canadian habitat requirements; in many instances therefore, studies from other regions are used as a proxy. Small streams (e.g., 2 – 10m wide and <1 m deep) are preferred over large ones, although they have been found in lakes and large streams on rare occasions. Water clarity (clear to turbid) and elevation (20-800 m) vary greatly across habitats. Fish are typically found along shorelines where cover is more abundant, however larger vegetation, including pondweeds, muskgrass, algae, and cress, is not always present. Studies from Montana show that substrate composition varies widely, but cobbles appear to be the most common type.
Typical food for the Mountain Sucker consists of plankton, small invertebrates, and microscopic organic matter scraped from the surface of rocks. Spawning occurs in late spring/early summer; at such time typically 990 – 3,710 eggs are laid, usually hatching within two weeks. A typical length reached by young of the year is 30 - 64mm.
Threats to Pacific populations include: • water availability, use and climate change; • channelization and siltation; • impoundments and flow regulation; • toxicity (e.g. chemical spills); and • exotic species. The Mountain Sucker’s naturally fragmented distribution renders them more susceptible to cumulative effects from a multitude of threats, rather than one primary threat. Populations of the Similkameen River are likely the most affected by habitat degradation due to development and mining activities.
In Canada, the species is afforded protection under the Fisheries Act, and is currently under consideration for listing as Special Concern under the federal Species at Risk Act (SARA). More information about SARA, including how it protects individual species, is available online at www.AquaticSpeciesAtRisk.ca or on the SARA Registry at www.SaraRegistry.gc.ca.
Provincial and Territorial Protection
Other Protection or Status
Provincially, the Mountain Sucker is on the Blue List in British Columbia.
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 (1 record(s) found.)
- Response Statements (1 record(s) found.)
- Orders (2 record(s) found.)
- COSEWIC Annual Reports (1 record(s) found.)
COSEWIC Status Reports
COSEWIC Annual Reports
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