Food Conditioning and Prey Selection by Young Yellow Perch (Perca flavescens)

Abstract

We tested how diet conditioning influences prey species selection by age-0 yellow perch (Perca flavescens) in laboratory experiments. We conditioned yellow perch to diets of different ratios of Daphnia pulex and Diaptomus sicilis and then offered them an experimental 1:1 test mixture of each prey. The influence of conditioning on prey selection was found not to be random, and prey were consumed neither in proportion to the 1:1 test mix nor to the ratio of prey in the conditioning diet. Young yellow perch switched to novel prey and did not specialize on the most frequently encountered prey in conditioning diets. However, when yellow perch were conditioned and tested on the 1:1 Diaptomus to Daphnia mix, these fish selected Diaptomus until they reached 35–40 mm total length when they switched to the larger bodied Daphnia. We hypothesize that young yellow perch may switch to novel prey because nutritional advantages associated with diet breadth may outweigh the advantage of feeding on familiar prey.