Caloric densities of selected fish prey organisms in the lower Mississippi River

Estimates of caloric density and associated variation were generated for several common species of fish prey in the lower Mississippi River. Estimates were derived for eight common fishes including gizzard shad (Dorosoma cepedianum), threadfin shad (D. petenense), blue catfish (Ictalurus furcatus), flathead catfish (Pylodictis olivaris), brook silverside (Labidesthes sicculus), freshwater drum (Aplodinotus grunniens), white bass (Morone chrysops), and bluegill (Lepomis macrochirus) and for two decapod species, the giant river prawn (Macrobrachium ohioni) and a Procambarus crayfish species. Generated values for gizzard shad and bluegill were comparable to literature values; values for the other fishes and the two decapods have not been reported previously. Seasonal trends in caloric density were evident for blue catfish and gizzard shad. Though caloric content peaked at different times of the year for each species, values were consistently most variable during spring for both species.