Smallmouth Buffalo

Characteristics

Body color is bluish-gray dorsally blending into silvery blue sides, fading into white or yellowish on the belly. Its body is compressed, and the back is elevated giving a hump-backed look. The mouth is small, sub-terminal, nearly horizontal and extends distinctly downward. Its head is small and compressed with thick strongly-grooved lips. The lateral line is complete with 36 to 38 large scales. The dorsal fin is sickle-shaped with 26 to 31 fin rays.

Distribution

Abundant and widely distributed throughout the Mississippi and Missouri Rivers. Less often collected in the large tributaries of these rivers, including the Des Moines, Cedar, Iowa and Big Sioux Rivers. Occasionally taken in Iowa’s natural lakes, especially East and West Okoboji and Spirit Lakes.

Foods

Smallmouth Buffalo are opportunistic feeders that eat a variety of food items from season to season. Stomach content samples show that it is mainly a bottom feeder foraging on a variety of aquatic insect larvae, attached algae, detritus and zooplankton.

State Record

43 lbs; 36 in. - Wapsipinicon River, Jones County, December 1, 2021 - John Dirks, Anamosa, Iowa

Expert Tip

While it is possible to catch these fish on a hook and line, snagging or bow fishing are the most likely ways to get this fish.

Details

At one time this species was rare in all Iowa waters, surpassed in occurrence by both black and bigmouth buffaloes. In recent years its abundance has increased to where it currently is equal to the latter species, and it is more abundant than Black Buffalo. 

The Smallmouth Buffalo lives in the deep pools of streams, large rivers, backwaters in the mouths of tributaries and oxbows with moderate current, rocky bottoms, clear water and debris, such as “deadfalls” or log drifts. It lives in clearer water than the Bigmouth Buffalo and slower currents than the Black Buffalo. In Iowa, it prefers clear, deep waters of moderate to swift current over a mixture of sand, gravel and silt. In the Great Border Rivers, the Smallmouth Buffalo seeks out rip-rap structures and scour holes around wing dams. It is often found in large schools along with Bigmouth Buffalo.

Spawning occurs in late April or June at water temperatures of 60 to 65 degrees. Maturity varies, but most are sexually mature and spawn in the third year of life. Spawning occurs over shallow water from 4 to 10 feet deep in slow to moderate current as the fish gather in large schools. Often the spawning grounds are found over submerged gravel or sand bars that are next to river channels. Eggs are broadcast at random, fertilized by several males and sink to the bottom where they stick to any object. Incubation lasts 8 to 14 days. An age 2 female produces 18,200 eggs. Growth of fish from Pool 10 of the Mississippi River was 4.4-inches at age 1, 9.6-inches at age 2, 13.6-inches at age 3, 15.4-inches at age 4, 16.9-inches at age 5, and 18.2-inches at age 6.

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.

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.