Comparison of otolith and scale ages for yellow perch from Lake Michigan

The age composition of the yellow perch (Perca flavescens) population in Lake Michigan is assessed annually by five management agencies, but all agencies do not use the same structure to estimate ages. The reliability of the most commonly used structure, scales, has not been formally evaluated for this population. We compared ages estimated by three readers from scales and sagittal otoliths for 150 yellow perch from southwestern Lake Michigan. The maximum age of yellow perch determined from scales and otoliths was 12. Otoliths had better precision (reproducibility) and usually had more annuli than scales for all three readers. Scale ages were usually younger than otolith ages when otolith ages were greater than or equal to 7. Chi-square tests revealed significant differences (P <0.05) between the age distributions determined from scales and otoliths for two of the three readers. We recommend use of otoliths for aging Lake Michigan yellow perch greater than 150 mm in length because of greater precision, easier readability, and detection of more annuli.