Food Selectivity of Bigmouth Buffalo, Ictiobus cyprinellus, in Lake Poinsett, South Dakota

Food habits and food selectivity of bigmouth buffalo, Ictiobus cyprinellus, in Lake Poinsett, South Dakota were studied from January through November 1968. Food of bigmouth buffalo fry ranging from 12.5 to 21.0 mm total length was primarily benthic organisms. Food of sub-adult and adult bigmouth buffalo ranging from 236 to 833 mm total length was primarily zooplankton. Most planktonic organisms were consumed in about the same proportion as they were available. Selectivity was greatest for adult Daphnia pulex, the largest food item present, and least for calanoid copepods. The bigmouth buffalo in Lake Poinsett might best be described as an indiscriminate planktivor throughout most of its life history.