Predicted probabilities of ramp attraction efficiency (A_eff), passage efficiency (P_eff) and overall efficiency (overall P_eff) as a function of fish length, river discharge, water temperature and species, resulted from mixed linear models for A_eff and overall P_eff, and from logistic generalized linear model for P_eff (the significance of each variable was tested with ANOVA, see Suppl. Material for details).