The Spotted Sucker...a Species at Risk

This species has been identified as Special Concern by the Committee on the Status of Endangered Wildlife in Canada (COSEWIC). It is listed under the federal Species at Risk Act (SARA) and is afforded protection under the SARA. Additional protection is afforded through the federal Fisheries Act. Under the SARA, a management plan has been developed for this species.

General Description

Minytrema melanops

© J. R. Tomelleri

The Spotted Sucker (Minytrema melanops) is a member of the Sucker family (Catostomidae) and has the following characteristics:

• Body rather elongate and somewhat compressed laterally as adults, and more cylindrical as young;
• Average length of Ontario adults is 22 to 28 cm and weight rarely exceeds 1 kg;
• Small, protrusible, suctorial mouth;
• No teeth in mouth, pharyngeal teeth are short;
• Distinctive rows of square, brown-black spots on the base of the exposed portion of each scale; more conspicuous on sides, forming eight to ten rows along the body beyond the head;
• Dorsal surface and upper sides dark olive to brown; sides of body mostly bronze green, coppery or silvery; undersides milky white or silvery; copper luster everywhere; and
• Dorsal, caudal and anal fins olive grey; other fins dusky to white.

Distribution

The Spotted Sucker lives in eastern and central North America from the lower Great Lakes east to Pennsylvania, south to the Gulf Coast and Florida, and west to Texas. In Ontario, the species has been reported in Lake St. Clair and western Lake Erie as well as the Detroit, St. Clair, Sydenham and Thames rivers.

Habitat and Life History

The Spotted Sucker prefers clear lakes, creeks and small rivers with sandy, gravely, or hard-clay bottoms without silt. It is reportedly intolerant of turbidity and clay-silt bottoms; however, it has been found in turbid waters in Ontario. In late spring and early summer, suckers move to rocky riffle areas of streams to breed.

Diet

The Spotted Sucker feeds on molluscs and immature aquatic insects.

Threats

The Ontario population represents the northern limit for the species, and it may always have been uncommon. Siltation and deteriorating water quality are likely threats in the Sydenham and Thames rivers and Essex County sites. In other parts of its range, the species has declined because of decreases in water quality from siltation and pollution.

Similar Species

Younger fish resemble the White Sucker (Catostomus commersoni) but become more like the Redhorses with age.

Text Sources: Trautman 1981; Campbell 1994; Scott and Crossman 1998.

For more information, visit the SARA Registry Website at www.SARAregistry.gc.ca.