Freshwater Drum

The Freshwater Drum is the only member of the family Sciaenidae that lives entirely in fresh water, making it a taxonomic outlier among the mostly marine and estuarine drums and croakers. It is the sole species in the genus Aplodinotus and has an extensive native range across central North America, from the Hudson Bay drainage south through the Mississippi River basin to Guatemala. The species is named for the drumming sound it produces and is also known by names such as sheepshead or gaspergou in different regions. Freshwater Drum are widespread and abundant, playing an important ecological role in large river and lake systems throughout their range.

Freshwater Drum have a deep, humpbacked body distinct from most other freshwater fish.

• Color: silvery-grey to bronze body, sometimes with a purplish sheen
• Body shape: deep-bodied with a pronounced arched back and blunt snout
• Lateral line: extends onto the tail, a feature unique among North American freshwater fish
• Fins: long-based dorsal fin with a spiny and soft portion
• Otoliths: unusually large ear bones, among the largest of any freshwater fish

The lateral line extending onto the caudal fin is a key diagnostic feature separating Freshwater Drum from all other native freshwater fish in its range.

Freshwater Drum inhabit large rivers, lakes, and reservoirs across central North America, from the Hudson Bay and Great Lakes drainages south through the Mississippi River basin into Mexico and Central America. They favor turbid, slow-moving water over sand, mud, or gravel bottoms and are commonly found in deep pools, river channels, and open lake waters. The species tolerates a wide range of water clarity and temperature conditions, contributing to its broad distribution. Freshwater Drum are typically absent from small headwater streams, favoring larger, more permanent water bodies.

Freshwater Drum are bottom-oriented foragers that feed heavily on mollusks, insect larvae, and small fish, using strong pharyngeal teeth to crush hard-shelled prey such as snails and mussels. They often travel in loose schools, particularly in open lake and river habitats, and can be active both during the day and at night. Males produce a distinctive drumming or grunting sound using muscles associated with the swim bladder, especially during the spawning season in late spring and summer. Eggs are broadcast into open water and float at the surface, an unusual trait among freshwater fish. As shell-crushing predators, Freshwater Drum help control mollusk populations, including some invasive species.