Spotted sucker (Minytrema melanops) COSEWIC assessment and status report: chapter 3
Species Information
Name and classification
Recent phylogenies of North American catostomids have consistently grouped the Spotted Sucker with species of the genus Erimyzon (Smith 1992, Harris and Mayden 2001, Harris et al. 2002). Harris et al. (2002) recommended resurrection of the Tribe: Erimyzoninim, which includes Spotted Sucker, lake chubsucker (E. sucetta), creek chubsucker (E. oblongus) and sharpfin chubsucker (E. tenuis).
Description
A medium-sized catostomid (sucker) that averages as adults between 230 and 380 mm in length. Individuals as large as 500 mm in length have also been captured. Most specimens weigh less than 1000 g, although individuals over 1300 g have been collected. Spotted suckers are distinguished from other catostomid species by the presence of 8-12 parallel rows of dark spots on the base of the scales (Dextrase et al. 2003) (Figure 1). Juvenile Spotted Suckers are torpedo-shaped and resemble white sucker (Catostomus commersoni). As they mature, Spotted Sucker become deep-bodied and narrow in breadth, resembling redhorse suckers (Moxostoma sp.) (Campbell 1994). The dorsal surface is brown to dark green, the sides silver to bronze and the ventral surface white and silvery. Breeding males have two dark lateral bands separated by a pinkish band along the midside. Tubercles are present on the snout, anal fin and both lobes of the caudal fin of males. Fewer tubercles are present around the lower cheek and eye, and on the underside of the head.
Figure 1. Drawing of the spotted sucker (Minytrema melanops). Illustration by Joe Tomelleri used with permission of DFO.
Designatable units
All Canadian populations are found within the Great Lakes-Western St. Lawrence ecozone of the freshwater ecozone classification adopted by COSEWIC (2003). Population structure is unknown.