Black Redhorse

Characteristics

A slender, fine-scaled sucker similar in appearance to the Golden Redhorse. Dark olive-green body with brassy sides and white belly. The fins, especially the dorsal and tailfin, are dark, slate-gray. The lateral line is complete with 44 to 47 small scales, which distinguishes it from the Golden Redhorse. Pharyngeal teeth are narrow and fragile. Breeding males develop small tubercules over much of the body. It's a small sucker; few weigh more than 2 pounds and 17-inches long.

Distribution

The Black Redhorse is a threatened species in Iowa (571 IAC 77.2(2) (2015)). Previously, the range of this species was thought to be limited to the Turkey and Upper Iowa River drainages. Their current distribution is more broadly recognized as including the Cedar River and all other river networks in northeast Iowa (Eastern Broadleaf Forest Aquatic Subregion). It has been found in the Des Moines, North Raccoon and South Skunk drainages in central and north-central Iowa (Central Plains Aquatic Subregion).

Foods

Aquatic insect larvae and small mollusks

State Record

Not allowed for threatened or endangered species

Expert Tip

It is illegal to fish for, take or possess threatened or endangered species, including the Black Redhorse.

Details

The Black Redhorse is most abundant in clear streams of small to medium size, but lives in streams of all sizes. Researchers found that its abundance in the Missouri River could be most closely linked to volume of flow. In headwater creeks and stream branches it is replaced by the White Sucker, and in larger rivers by golden, shorthead and river redhorses. The Black Redhorse prefers cooler, swifter streams in short, gravelly pools with considerable, but smooth current. The Black Redhorse is intolerant of pollution, siltation, turbidity and low gradients.

Spawning occurs in April and May at 56 to 72 degrees. Very shallow riffles, less than two feet deep, over gravel and cobble bottom are selected as spawning sites. Spawning behavior is different than the redhorses. Males defend the spawning shoals, which average 1.5 feet in diameter. Two territorial males spawn with a single female. Age of sexual maturity varies and fertility is unknown. Black Redhorse are  long-lived, commonly reaching 9 years old and about 14-inches long.

Like the other redhorse species in Iowa, these fish have minimal importance to anglers.  It is viewed as imperiled according to the Iowa Wildlife Action Plan, and it is on the threatened species list in Iowa (571 IAC 77.2(2) (2015)).

Recent stream sampling information is available from Iowa DNR's biological monitoring and assessment program.

Sources:

Harlan, J.R., E.B. Speaker, and J. Mayhew. 1987. Iowa fish and fishing. Iowa Conservation Commission, Des Moines, Iowa. 323pp.

Iowa Department of Natural Resources, Iowa Wildlife Action Plan

Loan-Wilsey, A. K., C. L. Pierce, K. L. Kane, P. D. Brown and R. L. McNeely. 2005. The Iowa Aquatic Gap Analysis Project Final Report. Iowa Cooperative Fish and Wildlife Research Unit, Iowa State University, Ames

Photo Credit: photo courtesy of Konrad P. Schmidt, copyright Konrad P. Schmidt