Absolute growth rates (ω parameter derived from the modeled von Bertalanffy growth function) were compared among populations using one-way analysis of variance (ANOVA) following a priori diagnostic tests for homogeneity of variance between groups and normal distribution of data. Standard linear regressions were used to assess relationships between SGI, NAO, and river discharge patterns. Student's t-tests were used to determine whether statistically significant differences exist between the ranges of intra- and inter-annual geochemical data. We used Pearson correlations and linear regressions to compare trace elemental ratios and stable isotope profiles within individual shells. Errors are reported as standard deviations unless otherwise stated. Statistical computations were carried out with Microsoft Excel and Statistica (ver. 6).