(A) Lengths at last annulus by age of Barbus barbus across the study sites (clear circles) and the modelled length at age (black line); (B) mean standardised growth residuals from length at last annulus per study reach, where ⁎ denotes difference of the mean for that reach is significantly different to Reach 1 according to pairwise comparisons in the generalised linear model (P < 0.01); and (C) mean standardised growth residuals from length increment between age 1 and 2 years.