Freshwater Drum - (Aplodinotus grunniens)
Length: up to about 14 inches, although it may become quite large in rivers
Weight: 5-15 pounds, world record is 54 1/2 pounds
Coloring: Gray or silvery in turbid waters, bronze-colored in clearer waters. The head is somewhat darker than the rest of the body; the ventral portion of the fish is white. The pectoral and pelvic fins are white, but the rest of the fins are dusky.
Common Names: sheepshead, croaker, thunder pumper, lake drum, grunt, bubbler, grinder
Found in Lakes: all Great Lakes
The freshwater drum is the only member of its family that lives entirely in freshwater habitats, and it has the largest native range of any sport fish in the region. Drum are an important commercial crop on the Mississippi River but constitute only a small portion of the commercial perch catch in Lake Michigan.
The drum earned part of its Latin name, "grunniens" (meaning "grunting"), by its odd grunting noises, which are produced by a special set of muscles located in the body cavity that vibrates against the swim bladder. The purpose of the noise is unknown, but only mature males develop the structure (by the time they reach three years of age), suggesting that it is most likely related to spawning. Drums also may croak like bullfrogs when removed from the water, and scientists still don't know if the croaking noise is generated in the same way.
Identification of this fish is fairly easy. Drum have two dorsal fins that are joined by a narrow membrane. The anterior fin is spiny, and the posterior fin has soft rays. The are the only fish found in Wisconsin with a lateral line that extends through the caudal fin.
The drum's otoliths are exceptionally large and look a great deal like ivory. In times past they have been worn as protective amulets, made into jewelry, and traded into areas far from the fish's native range (such as Utah and California).
Drum are a bottom-dwelling species found in lakes and rivers; they tolerate both clear and turbid conditions. Their diet consists mainly of immature insects, crayfish, and minnows, although they may also feed on mollusks.
The white, flaky flesh of the drum is tasty and has a low oil content. (nutritional information) When cooking, be sure that the fish doesn't dry out and become hard. The low oil content means that fillets dry out much more quickly than other, more oily, fish. Recommended cooking methods include pan frying (in batter) or deep fat frying. Smoking also works well, as long as you're careful not to heat them for too long.
Freshwater drum are good fighters and will take bait such as crayfish, minnows, and worms. In warm weather they move in schools to shallow waters to feed and possibly spawn (spawning has not been witnessed by scientists). By winter their activity levels and feeding activity are sharply reduced.
copyright 2001 University of Wisconsin Sea Grant Institute
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