How to Identify White Sucker

To identify White Sucker (Catostomus commersonii), look at these key features.

Physical Characteristics

Body shape

elongated

Coloration

Dorsal surface typically olive-brown to dark gray, fading to lighter flanks and a white or yellowish belly. Spawning males may develop a pinkish lateral band and nuptial tubercles.

Scale type

cycloid

Mouth position

subterminal

Distinctive features

Subterminal, protractile mouth with thick, fleshy, papillose lips adapted for suction feeding on bottom substrates., Absence of barbels., Large, cycloid scales., Single dorsal fin without spines.

Dorsal fin

Single dorsal fin, typically with 10-13 soft rays. Origin usually anterior to the pelvic fin origin.

Tail fin

Moderately forked caudal fin.

Pectoral fin

Pectoral fins are relatively small and low-set.

Distinctive fins

Pelvic fins are abdominal, located well behind the pectoral fins.

Identification Tips

1. 1

   Mouth

   The most distinguishing feature is the subterminal, fleshy, papillose mouth located on the underside of the head, clearly adapted for suction feeding on the bottom. It lacks barbels.

2. 2

   Scales

   Possesses relatively large, cycloid scales, which are smooth to the touch. The lateral line is complete and typically has 55-70 scales.

3. 3

   Dorsal Fin

   A single dorsal fin with no spines, usually containing 10-13 soft rays. Its origin is typically anterior to the pelvic fin origin.

4. 4

   Body Shape and Coloration

   Elongated, cylindrical body. Coloration is generally olive-brown to dark gray dorsally, fading to lighter sides and a white belly. Spawning males develop a distinct pinkish lateral band and small, wart-like nuptial tubercles on the head and fins.

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