Mountain Sucker (Pacific populations)

Catostomus platyrhynchus

SARA Status
No Status
NS
Special Concern
SC
Threatened
TH
Endangered
EN
Extirpated
EX

SARA Status

  • No Status NS
  • Special Concern SC
  • Threatened TH
  • Endangered EN
  • Extirpated EX
COSEWIC Status
Not at Risk
NR
Special Concern
SC
Threatened
TH
Endangered
EN
Extirpated
EX

COSEWIC Status

  • Not at Risk NR
  • Special Concern SC
  • Threatened TH
  • Endangered EN
  • Extirpated EX

Description

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 15mm in length.

Habitat

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. 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.

Threats

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 habitat 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.

Further Information

Provincially, the Mountain Sucker is on the Blue List in British Columbia. It is also considered vulnerable in British Columbia by NatureServe.

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

For more information, visit the Species at Risk (SARA) Public Registry Profile.

Mountain Sucker (Pacific populations)

Illustration of a Mountain Sucker (© Joseph R. Tomelleri)

© Joseph R. Tomelleri

Scientific name: Catostomus platyrhynchus
SARA Status: Special Concern
COSEWIC Status: Special Concern
Region: British Columbia

Did You Know?

The Mountain Sucker was not discovered in British Columbia until the mid-1950's.

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