River Carpsucker

The physical appearance of the river carpsucker is fairly distinctive. It is stout, with a somewhat compressed and arched back. The area around its dorsal fin is olive-brown before it fades to silver, with a white belly. In the young, the fins are usually opaque, while in the old, their fins are a dark yellow. The lower lip is projected in a similar fashion to a nipple at the midpoint, and big scales cover its whole body. It also has a distinctive 18 caudal fin rays. The species is frequently confused with non-native species, such as the various Asian carp species.

The river carpsucker has historically occupied the Mississippi River basin from Pennsylvania to Montana. It also currently occupies the Gulf Slope Drainage from the Calcasieu River to the Rio Grande in Texas, Louisiana, and New Mexico. It was introduced to Lake Erie and the lower Maumee River, Ohio. It was supposedly deliberately introduced with a shipment of buffalofish as a game species, and they are currently used in sport fishing. The effects of its introduction have not been studied, so are not well known. However, failure to find more river carpsuckers in the lower Maumee River suggests this species never took hold in this area. In the spring, they migrate upstream as the water temperatures begin to rise, and then move back downstream after spawning. They have been known to travel distances of up to 10 kilometers (6.2 mi).

The river carpsucker is classified as a suction, or filter feeder, which means it typically eats algae and small planktonic animals and plants. They get their nutrients from filtering silt and detritus. It is typically preyed on by larger carnivorous fish such as northern pike, muskellunge, walleye, and largemouth bass, but mostly in its juvenile stage. Their largest predators are humans, although some larger birds, such as great blue herons, have been known to eat them. They can be found in large rivers and reservoirs, with sand or silt bottoms in slower-moving currents. The young typically are found in small streams, or tributaries. They are more abundant in areas with slower water velocity and moderate temperatures.