The white sucker is slender, with fine scales and a short dorsal fin. The scales are largest near the tail fin, becoming smaller toward the head. The lips are covered with small bumps. The back and sides are greenish with a brassy or silvery luster; the belly is white. This coloration makes it almost invisible when resting on a gravel stream bed. The dorsal and tail fins are dusky or clear; the lower fins are white, often tinged with yellow or orange.
Total length: 9 to 15 inches; maximum about 23 inches.
Nearly statewide, but absent from the Bootheel lowlands and the southeastern Ozarks. Abundant and generally distributed in prairie streams of central and northeastern Missouri. Locally common but spotty westward in the prairie region and over the parts of the Ozarks where it occurs.
Habitat and Conservation
Decidedly a small-creek fish, occurring only rarely in major rivers. In prairie regions, it is abundant in deep, sparsely vegetated pools of high-gradient, often intermittent headwater streams with gravelly or rocky bottoms. In the Ozarks, it occurs in rather densely vegetated spring branches, spring-fed streams, and cool overflow pools with groundwater seepage. Also found in Lake Taneycomo.
The white sucker lives in schools near the bottom.
Feeding habits and diet vary with age. For the first ten days of life, the young suckers have terminal mouths and feed near the surface on bloodworms, small crustaceans, protozoa, and similar. They soon develop the lower, horizontal mouth of the adults, and from then on they feed almost entirely on the bottom, starting with organic-rich bottom ooze, then moving on to a generalized diet of immature aquatic insects.
The white sucker is an early spring spawner. In central Missouri, spawning season extends from late March through April. Spawning occurs in gravelly areas near the lower ends of pools, in quiet water, or where the current begins to quicken. Many individuals occupy a single site and create a large area of clean, silt-free gravel by their activities. The males remain more or less continuously over the spawning area, but the females enter only when ready to spawn. Spawning is accompanied by violent vibrations that raise clouds of silt and bury the eggs in the gravel. The eggs hatch in 18 to 20 days at a temperature of about 50 F.
Individuals can live 17 years.
Folklorist Vance Randolph reported that oldtime Ozark fishermen told him that redhorse and white suckers did not spawn until they saw dogwood trees blooming on the banks of the White River. While it is unlikely that the fish are actually looking for flowers, it is very likely that the water reaches the correct temperature for spawning about the same time dogwoods are blooming. The study of annual cycles and seasons of natural events (and their interrelationships) is called phenology.
Suckers are one of the dominant groups of large fishes in Missouri waters. Each kind of sucker has its own particular habitat preference. Suckers feed mostly by sucking up material from the bottom. The different types of suckers have slightly different positioning and shapes of their mouths, which causes them to specialize in different kinds of foods. The white sucker's mouth positioning changes as it grows from a fry to a fingerling to an adult.