Body color of the smallmouth buffalo is bluish-gray body dorsally blending into silvery blue sides, fading into white or yellowish on the belly. The body is compressed, and the back is grossly elevated giving a humpbacked appearance. The mouth is small in size, sub-terminal, nearly horizontal and protracts distinctly downward. The 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
The smallmouth buffalo is abundant and widely distributed throughout the Mississippi and Missouri Rivers. It is less frequently collected in the large tributaries of these rivers, including the Des Moines, Cedar, Iowa and Big Sioux rivers. The smallmouth buffalo is occasionally taken in Iowa’s natural lakes, especially East and West Okoboji and Spirit Lakes.
Smallmouth buffalo are opportunistic feeders and consume a variety of food items from season to season. Stomach content samples indicate that it is primarily a bottom feeder foraging on a variety of aquatic insect larvae, attached algae, detritus and zooplankton.
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.
Smallmouth buffalo are found in greatest abundance in the Mississippi and Missouri rivers, where it is widely distributed in all reaches. At one time this species was rare in all Iowa water, surpassed in occurrence by both black and bigmouth buffaloes. In recent years its abundance has increased to the point where it currently is equal to the latter species, and it is far more abundant than black buffalo. Smallmouth buffalo occur rarely in the large interior streams and the natural lakes, specifically the Okoboji`s and Spirit Lake.
The smallmouth buffalo inhabits the deep pools of streams, large rivers, backwaters in the mouths of tributaries and oxbows and is associated with moderate current, rocky bottoms, clear water and debris, such as “deadfalls” or log drifts. The smallmouth buffalo inhabits 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. Often it is found in large schools along with bigmouth buffalo.
Spawning occurs in late April or June at water temperatures of 60 to 65 degrees F. Maturity varies, but most are sexually mature and spawn in the third year of life. Spawning activity occurs over shallow water from 4 to 10 feet in depth in slow to moderate current as the fish congregate in large schools. Often the spawning grounds are found over submerged gravel or sand bars that are adjacent to river channels. Eggs are broadcast at random, fertilized by several males and sink to the bottom where they adhere to any object. Incubation lasts 8 to 14 days. Fecundity of an age II female is 18,200 eggs. Growth of specimens from Pool 10 of the Mississippi River was 4.4 inches at age I, 9.6 at II, 13.6 at III, 15.4 at IV, 16.9 at V, and 18.2 at VI.
Recent stream sampling information is available from Iowa DNR's biological monitoring and assessment program.
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.