The Influence of Predation and Spawning Phenology on Yellow Perch Reproduction and Recruitment in Prairie Pothole Lakes

Yellow perch Perca flavescens reproduction and recruitment are highly variable among years, and often quite limited, in most eastern South Dakota lakes.  Previous research suggested abiotic factors such as spring precipitation and air temperatures can influence spawning success, however much of the variability is still unexplained.  Our objective was to determine if predation and timing of spawning affect reproduction and recruitment of yellow perch in Eastern South Dakota prairie pothole lakes.  A long-term larval data set was used to assess reproduction and a long-term gill net catch-per-unit-effort (CPUE) data set for age-2 yellow perch was used to index recruitment.  Adult and age-0 walleye Sander vitreus CPUE data were used as an index of predator density.  Date of peak larval abundance was used as a surrogate for hatch date.  Timing of peak larval abundance, and abundance of age-0 walleye were highly influential on larval densities.  Years with early peak larval abundances had variable reproduction and recruitment, years when peak abundance was in the middle period often had the highest abundances (larval and age-2) and years with late peak abundances had consistently low reproduction and recruitment.  Predation by age-0 walleye likely reduced larval abundances and predation by adult walleye was negatively related to recruitment of age-2 yellow perch.  Larval abundance and age-2 relative abundance were highest when perch hatched during the middle time period and walleye abundances were low.  When walleye abundance was high, yellow perch generally had lower recruitment, however when walleye densities were low, abiotic factors likely played a larger role in the recruitment process.