First-year growth of the yellow perch, Perca flavescens (Mitchill), was determined from 28,241 young-of-the-year fish collected in the Red Lakes during the summer (1 July-20 August) in 15 seasons and on back calculations from I-annulus fish of the same year classes. Sexes did not differ in growth rate. Geographic variations in first-season growth occurred in 2 years but were not reflected at I-annulus. A consistent seasonal growth pattern in all years was linear through the summer sampling period. Growth rate after 20 August gradually declined and became nearly asymptotic by the end of the season. Growth during midsummer varied widely in different seasons, but length at I-annulus was relatively uniform (71-79 mm) for most years as the result of apparent growth compensation. Negative correlations of length on 1 July with mid-summer rate of growth and, consequently, with I-annulus length were noted. Although high summer water temperature appeared to exert a positive influence on growth, it did not obscure the compensatory phenomenon. Growth compensation is probably not affected by predation, but may be related to interaction of perch size and food availability.