Freshwater Drum

Characteristics

A deep-bodied, silvery fish whose head and body slope steeply up from the snout to the dorsal fin, resulting in a hump-backed look. It has a long dorsal fin that is divided into two lobes. The first has 8 to 9 spines, and the second has a single spine with 24 to 32 soft rays. The anal fin has 2 spines with the second spine larger than the first. The pelvic fin has one spine with 5 rays. Ctenoid scales cover the body and upper head. The lateral line is complete and extends through the caudal fin. The back is gray, with silvery sides and white belly and lower region of the head. Adults commonly weigh up to 5-pounds.

Distribution

Abundant in large rivers, such as the Missouri and Mississippi; found in larger inland rivers and streams. It is less common in the interior streams of northeast Iowa. It can be found in Iowa's larger impoundments, reservoirs and deep, natural lakes.

Foods

Drum spend most of their time on or near the bottom feeding mainly on fish, crayfish, and immature insects. Moving slowly along the bottom, it moves small rocks and other bottom materials with its snout, catching displaced aquatic life.

State Record

46 lbs; 38.50 in. - Spirit Lake, Dickinson County, October 1962 - R.F. Farran, Clarion, Iowa

Expert Tip

Drum are bottom feeders that can be caught easily from the bank on nightcrawlers.

Details

The Freshwater Drum is usually found in shallow or muddy areas of large lakes, deep backwater pools of large rivers, and in reservoirs at depths of 30 feet or more. It avoids high gradient streams, waters with swift current and shallow, weedy areas, but can tolerate high turbidity.

The Freshwater Drum spawns in open waters. In the Mississippi River, drum spawn during May and June when the water temperatures are 66 to 72 degrees. Unique to the freshwater fish species in North America and characteristic of many saltwater fish, the eggs and larvae are buoyant and float on the water surface during development.

Growth studies in the Mississippi River report that Freshwater Drum average 5-inches long by the end of the first year of life and 8.0, 12.0, 13.5, 15.0, 17.0, 18.5, and 19.5-inches in succeeding years. Fast-growing drums in the Mississippi River reach 7 to 8 years of age, seldom more than 10 years, but there is a record of a 17 year old fish.

The drumming sound made when the fish is handled is produced by a special structure in the body cavity, which is connected with the swim bladder. Two elongated muscles move a tendon over the swim bladder and produce the sound. Only sexually mature males have this structure. Another unique feature of the drum is the large-sized otolith found in the sacculus. It has white, enameled surfaces and alternating light and dark bands that can be used to age the fish. Otoliths are often kept by fishermen for lucky pieces and sometimes made into jewelry.

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.

Illustration by Maynard Reece, from Iowa Fish and Fishing.