Dietary Effects of Non-native Species on Yellow Perch, Perca flavescens, Reproductive Performance

Abstract

In Lake Michigan, native yellow perch (Perca flavescens) have experienced poor recruitment since 1989. With the introduction of non-native species yellow perch prey fish have changed dramatically, which could affect successful recruitment of these fish. Therefore, in the present study I investigated dietary effects of two non-native species (alewife and round goby) on female yellow perch reproduction using lipid and fatty acid composition of their eggs, liver, muscle, and visceral fat. Two-year-old yellow perch were fed two diets, representing two distinct fatty acid signatures. These two diets were significantly different, in terms of fatty acid composition, with alewife containing higher concentrations of SAFA and MUFA and round goby having higher concentrations of PUFA. Unexpectedly, the entire dietary fatty acid composition was not reflected in tissues of yellow perch, but some individual dietary fatty acids were incorporated. Biosynthesis of linoleic acid into ARA and linolenic acid into EPA and DHA was also clearly observed in all tissues of yellow perch. Yellow perch fed round goby yielded a significantly higher body mass than yellow perch fed alewife (p < 0.05), but there were no significant differences in fecundity, embryo survival at pigmented eyed stage, HSI, or pseudo-GSI (p > 0.05). In conclusion, although round goby and alewife have high levels of n-3 and n-6 fatty acids, (which are general requirements for successful reproduction and recruitment by fish) successful reproduction of all female yellow perch was not observed in the present study. This observation could have been due to poor quality of egg ribbons; indicated by the ribbon separating in several places, and females spawning in tanks, thus limiting our ability to successfully fertilize eggs by hand.