Foraging selectivity by larval yellow perch (Perca flavescens): implications for understanding recruitment in small and large lakes

Abstract

Growth and survivorship of larval yellow perch (Perca flavescens) have been examined in many systems but can conclusions from well-studied perch populations in smaller lakes be applied to populations in meso-oceanic systems like Lake Michigan, USA? Laboratory experiments were conducted with yellow perch (hatch to 35 mm total length) to develop an empirical selectivity function based on Chesson's α to describe larval diet as a function of changes in prey community composition. This function was used in an individual-based foraging and growth model (IBM) to describe changes in foraging decisions resulting from changes in prey composition between different systems. Larval perch made three selective transitions during ontogeny. Initial positive selection for rotifers and the relative selectivity for cladocerans vs. copepods in late-stage larvae were both dependent on prey composition. Larvae exposed to prey assemblages differing only in composition had different diets. The empirically based IBM accurately predicted these dietary differences and resulting differences in larval growth and likelihood of starvation between systems at equal prey density. The importance of feeding behavior to larval survival will differ between Lake Michigan and smaller lakes, and these results are important for comparisons of recruitment dynamics between large and small systems.