Freshwater Drum
Aplodinotus grunniens Rafinesque, 1819

member of the Drum Family (Sciaenidae)

Minnesota River, Lac qui Parle County Minnesota 29 June 1985

young of the year

photos by Konrad Schmidt













What's In a Name?
Freshwater drum: this is the only freshwater species in the drum family; "drum" refers to the low grunting sound mage by members of this family

Aplodinotus (ah-ploe-din-oh´-tuss) means "simple back" in Greek, referring to the fin on the back not being in two parts as in perch
grunniens (grun´-ee-inns) means "grunting" in Latin, referring to the sounds made by this species


    Where Do They Live?
Freshwater drum are native to the lower Mississippi, St. Croix, Minnesota, and Red river drainages of Minnesota. They apparently have been introduced recently to the St. Louis River estuary and some lakes in southwestern Minnesota. There is also a recent record from Lake of the Woods. Freshwater drum inhabit large rivers and shallow lakes with bottoms made of mostly mud or a mixture of mud and sand. They prefer slow-moving turbid (cloudy) water, but can be found in moderate currents. They are rarely found in areas of vegetation.


How Big Do They Get?
How Long Do They Live?
Most freshwater drum encountered today in Minnesota are small, less than 300 mm (12 in) long and under 1 kg (2.2 lbs). However, freshwater drum can get much bigger. Records from early in the 20th century show Mississippi River drum reaching 600 mm (24 in) and almost 4.5 kg (10 lbs). Wisconsin records go to 937 mm (37 in) and almost 16 kg (35 lbs). Drum from Spirit Lake, Iowa, weighed over 23 kg (50 lbs).

Freshwater drum is another species that lives longer that it scales indicate. We have to look at otoliths (ear bones) to get an accurate age for fish older than 10 years. We know that drum used to live for many years (over 45 in at least one case), but today's populations have few individuals over 7 or 8 years old in them.

"Cool Fact": Native Americans used the otoliths (ear bones) from this fish as jewelry.

    What Do They Eat?
Larval drum, like many other species in Minnesota, eat mostly copepods and waterfleas. As they grow to about 25-30 mm (about 1 in), they add small insect larvae to their diet, especially midge larvae. As fully formed juveniles and adults, freshwater drum are benthic (bottom dwellers). So they feed on bottom dwelling creatures. These include insect larvae, like midges and burrowing mayflies, crayfish, snails, and small fishes. Drum have plates of teeth in their throats for crushing food items. Many biologists have assumed that they were used to crush freshwater mussels, but we have not yet proved this. However, they do eat the exotic zebra mussel, at least in Lake Erie.

What Eats Them?
Young freshwater drum are eaten by walleye, burbot, sauger, and white bass; but adults seem to have few natural predators. Even sea lamprey in the Great Lakes attack drum very rarely, probably because of the drum's thick and tough covering of scales. The commercial fishing industry has the biggest impact on these fish, although not here in Minnesota.


How Do They Reproduce?
Freshwater drum spawn in May and June in Minnesota, after water temperatures reach 19° C (about 66° F). They are pelagic spawners, which means they release their eggs into deep, open waters of lakes and large rivers. Spawning occurs near the surface of the water, often when the drum are swimming in schools. The males make a grunting or a rumbling sound, which is considered a mating call to the females. A single female can lay 40,000-500,000 eggs, depending on her size and health. The fertilized eggs float at the surface of the water, where they develop very rapidly over a period of 1-2 days. After they hatch, the embryos attach to the water's surface and continue to develop their mouths, guts, and fin rays for another 1-2 days. Once they release themselves from the surface, they begin to feed and are moved around the lake or river by water currents.


Conservation and Management
Freshwater drum are not a popular sport fish, but a few anglers do fish for them. Most anglers catch then while fishing deep for other species. In the early part of the 20th century, freshwater drum were an important commercial species. They still are in some parts of their range.




Permission is granted for the non-commercial educational or scientific use of the text and images on this Web document. Please credit the author or authors listed below.

Photographs by Konrad P. Schmidt
Text by Nicole Paulson & Jay T. Hatch in cooperation with
the Minnesota Department of Natural Resources' MinnAqua Aquatic Program

This page developed with funds from the
MinnAqua Program
(Minnesota Department of Natural Resources, Division of Fisheries)
and the
Sport Fish Restoration Program (Fish and Wildlife Service, US Department of the Interior)

Maintained by Jay T. Hatch
General College and James Ford Bell Museum of Natural History
University of Minnesota, Minneapolis/St. Paul

Last updated 23 October 2002