White Sucker

Key Characteristics:

  • Anal opening very far back, more than in Cyprinidae.
  • A line of pigment along the top of the fish, and a thinner one along lateral line.
  • Sleek “minnowy” look
  • As they grow, mouth will look rounder and you will begin to see downturned sucker begin to form.
  • In Lake Michigan the more prevelant Catostomidae are white suckers
  • Fins remain undefined and close to the body for most of larval stages.
Caption

Larval White Sucker. 15.81 mm. United States Fish Wildlife Service. Green Bay Harbor, WI. Ashley Smith. 2017.

Caption

Larval White Sucker. 15.81 mm. United States Fish Wildlife Service. Green Bay Harbor, WI. Ashley Smith. 2017.

Caption

Larval White Sucker. 17 mm. United States Fish Wildlife Service. Green Bay Harbor, WI. Adam Dziewa. 2018.

Caption

Larval White Sucker. 19.5 mm & 20.5 mm. United States Fish Wildlife Service. Green Bay Harbor, WI. Adam Dziewa. 2018.

Caption

White Sucker. 41.5 mm. United States Fish Wildlife Service. Green Bay Harbor, WI. Adam Dziewa. 2018.

Dr. Auer’s Dichotomous Key

  • Body not elongated, eel-shaped, round in transverse section, uniformly pigmented (1B)
  • Chin barbels absent (3B)
  • Snout short, its length usually less than 10% TL; median fins otherwise (5B)
  • Median fins or finfolds showing distinct separation (7B)
  • No adipose fin, or demarcation of one, in finfold (10B)
  • Preanal myomeres greater than or equal to postanal myomeres (14A)
  • Preanal myomeres significantly greater than postanal myomeres (difference greater than five myomeres) (15B)
  • Postanal myomeres usually less than or equal to 10 (26A)
  • Preanal length 59 – 73% TL, ratio of preanal to postanal myomeres less than or equal to 5.0 (27B)
    • Catostomidae – Suckers

Adult History

  • Physical Description 
    • Cylindrical-shaped, rounded head, 55-85 lateral scales, snout barely extends lower lip, back is green/brown while the belly is white, and sides are gray, anal fin is far posterior with 7 rays, 10-13 dorsal rays, and breeders have a lateral stripe 
  • Spawning Habitat
    • Migrate up tributaries in riffles
    • Near the shoreline of lakes
  • Spawning Substrate
    • Shoreline Shallows in gravel or coarse sand bottoms (quick running water)
  • Spawning Behavior
    • Males may head tremble towards the female, protrude their jaw, or extend their dorsal fin
      • Courtship Behaviors
    • Do not build nests or defend their territory 
  • Time of Year
    • April – May in Lake Michigan
    • Spawning typically takes place at water temperatures of 45-50°F
  • Diet (Benthonic Fish)
    • Omnivores
      • Invertebrates, insects, crustaceans, plant matter
Caption

Adult White Sucker. UW – Sea Grant, UW – Madison, and NOAA. John Lyons. 2013.

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