Shorthead redhorse

Characteristics

head is shorter than other redhorse species, tailfin is bright red, upper lip often has a "pea shaped" swelling in the middle, large scales

Distribution

widely distributed throughout Iowa but is more abundant in streams in the northern and eastern regions of the state

Foods

aquatic insect larvae, some plant material, mainly algae

State Record

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Details

Formerly named the northern redhorse (Moxostoma aureouim), this species was renamed to the present nomenclature in 1973. This fish is widely distributed over most of Iowa, but it is far more abundant in streams in the northern and eastern regions of the state. Its wide range is probably due to its adaptability to changing environmental conditions and different habitats. The shorthead redhorse is abundant in the Mississippi River, common in the interior rivers and uncommon to rare in the natural lakes and the Missouri River drainage.

Moderate to swift current over sand and gravel substrate is preferred habitat for the shorthead redhorse. This sucker is adaptable to high turbidity, but it occurs most frequently in clear to slightly turbid water in the deeper stretches of the channel.

The shorthead redhorse is a slender, coarse-scaled sucker with a bright red tail fin. The head is shorter than other redhorse, its dorsal fin is strongly curved inward, having 12-13 or sometimes 14 soft rays. The upper lip often has a "pea-shaped" swelling in the middle. The rear margin of the lower lip is nearly straight with the lip folds divided into prominent papillae. The pharyngeal teeth are thin, comb-like with about 53 per arch. The lateral line is complete with 41 to 45 scales. Scale count around the caudal peduncle is 12.

Life history characteristics of shorthead redhorse are not notably different from other redhorses. Adults commonly reach 10 to 22 inches in length and weigh from 1 to 4 pounds. Maturity is attained at age III. Upstream spawning movements in large schools is common for male redhorses during early April at water temperature ranges of 47 to 60 degrees F. Males congregate and defend spawning territories that contain gravel riffles and rubble shoals. The actual spawning ritual occurs when a female moves into the gravel-lined troughs or nests and two males mate with a single female. The semi-adhesive eggs are broadcast which are unattended and hatch in 4 or 5 days. Fecundity of an 18-inch female is about 22,000 eggs. Growth of the shorthead redhorse averages 1.9 inches the first year of life, 16.0 inches at age V and 20.9 inches at 11 years of age in the Mississippi River. Aquatic insect larvae comprise the principal food items of shorthead redhorse, but some plant material, mainly algae, are also consumed.

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