Influence of hatch duration and individual daily growth rates on size structure of age‐0 smallmouth bass cohorts in two glacial lakes

Abstract –  We assessed hatch dates and daily growth rates of age‐0 smallmouth bass from two glacial lakes over a 3‐year period. Hatching durations (19–27 days among years) of smallmouth bass occurred from late May until late June. Mean daily growth rate of age‐0 smallmouth bass ranged from 0.56 to 1.56 mm·day −1 . Correlation analysis indicated that hatch date had little effect on daily growth rates. Hatch date was significant in explaining variation in total length (TL) of age‐0 smallmouth bass at time of capture in only three of six cases and hatch date never explained >50% of the variation in bass length. Daily growth rate significantly explained variation in smallmouth bass TL at time of capture in all six models, accounting for 31–86% of the variability in bass length. Our findings suggest that size structure of age‐0 cohorts in some populations may be more strongly regulated by variation in individual daily growth rate than by hatch timing.