Shorthead Redhorse

Moxostoma macrolepidotum

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Shorthead redhorse side view photo with black background
Shorthead redhorse, Moxostoma macrolepidotum
Lance Merry
Other Common Name
Shorthead Redhorse Sucker; Redfin Sucker
Family

Catostomidae (suckers) in the order Cypriniformes (carps, minnows, and loaches)

Description

The shorthead redhorse is a slender, coarse-scaled sucker with a short dorsal fin. The lower lips are broken up into parallel folds. Missouri specimens often have a distinctive pea-shaped swelling at the middle of the upper lip. The rear margin of the lower lip is nearly straight. The head is shorter than those of other redhorse suckers, its length (measured from tip of snout to outer edge of gill) going more than 4.5 times into the standard length (measured from tip of snout to base of tail). The scales of the back and upper sides each have an indistinct crescent-shaped dark spot at the base. The tail fin is bright red in life.

Overall coloration: Back and upper sides olive brown with golden reflections, the scales rather prominently dark edged; remainder of sides a rich golden yellow. Belly white. Dorsal fin olive or slate; tail fin bright red; lower fins plain or with orange tinge.

Breeding males have tubercles on all fins except the dorsal fin. Tubercles are best developed on the anal fin and lower lobe of the tail fin.

More characters: Dorsal fin contains 12 or 13 (rarely 14) rays. The lateral line is complete, with 41–45 scales. The outer margin of the dorsal fin is strongly curved inward (concave). The throat teeth on the lower half of the first arch are numerous, bladelike, and without flattened grinding surfaces. The air bladder has 3 chambers.

Similar species: Overall, the coloration is similar to the river redhorse. The river redhorse, however, has the rear margin of the lower lip forming a definite V-shaped angle (not straight); has a longer head (its length goes fewer than 4.5 times into the standard length); never has a pea-shaped swelling at the middle of the upper lip; and has the throat-teeth arch thick, with molar-like teeth (not thin, with slender teeth in a comblike series).

Size

Adult length: to about 9–16 inches; weight: commonly ⅓–1½ pounds. Largest Missouri specimens weigh just over 4 pounds.

Habitat and conservation

The shorthead redhorse is widely distributed and is the most abundant redhorse in downstream sections of the largest Ozark rivers and is exceeded in abundance only by the golden redhorse and black redhorse in many other streams of that region. The shorthead redhorse is also abundant in the northeastern part of the Missouri, where it frequents smaller streams than in the Ozarks.

No other Missouri redhorse is as adaptable in its habitat requirements as the shorthead redhorse.

The shorthead redhorse inhabits a diversity of stream types but is most abundant in medium-sized to moderately large rivers having strong flow and extensive areas of silt-free sand, gravel, and rubble substrate. Although tolerant of turbidity, it was absent from the excessively turbid waters of the Missouri River prior to construction of upstream dams. It is now nearly as prevalent there as in the upper and middle sections of the Mississippi River, where small numbers of shorthead redhorse have long occurred.

In large streams, the shorthead redhorse frequents the swifter water near riffles. In small streams, it is also found in pools without noticeable current.

Foods

The shorthead redhorse’s diet is similar to that of most other redhorse suckers, comprising primarily immature midges, mayflies, and caddisflies. The pea-shaped swelling on the upper lip, common in Ozark specimens, is apparently an adaptation for grubbing food among rocks and gravel in the substrate.

Distribution in Missouri

The shorthead redhorse is the most widely distributed redhorse in Missouri, occurring it least occasionally in streams over the entire state, except for the White River system upstream from the North Fork.

Life cycle

Spawning in the shorthead redhorse often is preceded by migrations out of the larger rivers into tributary streams and may result in concentrations of from several hundred to 3,000 individuals in a spawning area. This activity occurs in gravelly riffles in April. Groups of spawning shortheads remain separate from groups of golden redhorse that spawn on the same riffle. As many as seven individuals may simultaneously occupy one of the shallow trenches or circular nests in which spawning occurs. The maximum life span is 9 years or more.

Human connections

Suckers are seldom caught on hook and line, but many are taken by snagging and gigging, especially during their spring spawning runs. The various redhorse suckers are part of the commercial fishery in the Mississippi and Missouri rivers. In general, the flesh of suckers has a good flavor, but numerous small bones detract from its value as food.

Small suckers are an important source of forage for game fishes.

Ecosystem connections

As their name implies, suckers feed mostly by sucking up material from the bottom. The downward oriented mouth, with its fleshy, protrusile lips, help suckers take in food. Thus small, bottom-dwelling aquatic insects are converted into the form of a suckerfish, which itself may be converted into the flesh of a larger fish or a fish-eating bird, reptile, or mammal.