Utilization of Mayflies and Caddis Flies by Some Mississippi River Fishes

Abstract

Abstract At sampling stations in the Mississippi River near Keokuk, Iowa, during 1958 mayfly naiads, Hexagenia spp., comprised over 50 percent by volume of the food of channel catfish (Ictalurus punctatus), freshwater drum (Aplodinotus grunniens), mooneyes (Hiodon tergisus), goldeyes (Hiodon alosoides), and white bass (Roccus chrysops), and over 40 percent of the food of paddlefish (Polyodon spathula) and white crappies (Pomoxis annularis). These naiads were also eaten by shovelnose sturgeon (Scaphirhynchus platorynchus). Larval caddis flies, Potamyia flava, comprised over 60 percent of the food of the shovelnose sturgeon and between 10 and 20 percent of the food of mooneyes, goldeyes, and white crappies. The Hexagenia naiads found in the stomachs are the same kinds that ordinarily create a problem in the river communities but the nuisance species of caddis flies (Cheumatopsyche campyla and Hydropsyche orris) are not usually significant in the diets of the fish studied.