Also known as sheepshead, the freshwater drum is known for the rumbling and grunting sounds the males make to attract mates. It is a large, round-profiled, silver humpbacked fish.
General description:The freshwater drum is a rounded fish with a small tail and a silvery cast to its scales. Its mouth is located toward bottom of its face. It's the only freshwater fish on which the lateral line, a sense organ used to detect motion in the water, runs right through tail.
Size: A typical freshwater drum weighs about two pounds. The biggest freshwater drum caught in Minnesota weighed 35 pounds, 3 ounces. It was caught in the Mississippi River.
Color: The drum is purple-gray, with silver sides and white underneath.
Sound: Male drum produce a deep, rumbling sound in spring breeding season by rubbing tendons against their swim bladders.
Freshwater drum spawn in May and June when water temperatures reach 65 to 70 degrees F. The males and females meet at the surface of the water, where the female releases up to 300,000 eggs at a time. Unlike any other freshwater fish, the drum eggs float. This helps currents and waves spread the eggs throughout a river or lake.
Young drum eat insect larvae. Older fish eat crayfish, clams, snails, and small fish. Drum feed at or near the bottom of the lake or river, using their noses to flip stones over in search of food.
Young drum are eaten by walleyes, muskellunge and northern pike. Humans also eat drum. The commercial catch in the Mississippi River alone has been about 300,000 pounds per year in recent years.
Habitat and range
Freshwater drum are found through most of Minnesota except in the Lake Superior watershed. They prefer shallow, quiet water in lakes and streams. They like to hang out at the bottom but generally stay less than 40 feet deep. They can tolerate murky conditions.
Population and management
Drum are abundant in much of Minnesota and are in no danger of overharvest.
Freshwater drum have particularly large otoliths, stonelike objects found in the ear of many animals. The otoliths help the drum to sense when it is oriented vertically in water too cloudy to see clearly. These otoliths, which can be more than one inch in diameter, have been used by humans for currency, jewelry, and good luck charms.