Diet composition from allozyme analysis in the predatory cladoceran Bythotrephes cederstroemi

Investigating diet composition with visual analyses of gut contents requires that the predator consume recognizable hard parts. Soft tissue remains of prey in the gut of the predatory cladoceran Bythotrephes cederstroemi were identified with cellulose acetate electrophoresis. We found that B. cederstroemi collected from an offshore station in Lake Michigan had fed on cyclopoid and Calanoid copepods and Daphnia galeata. Many individuals had eaten more than one prey type. Allozyme electrophoresis is a relatively simple way to analyze trophic relationships in freshwater systems, especially when traditional analyses