Flow, force, behaviour: assessment of a prototype hydraulic barrier for invasive fish

Abstract Migration barriers being selective for invasive species could protect pristine upstream areas. We designed and tested a prototype protective barrier in vertical slot fish pass. Based on the individuals’ swimming responses to flow field, we assumed this would block ascension of round goby, but allow comparable native (gudgeon bullhead) ascend. The was three steps: description, quantification forces experienced by preserved tracking trajectories ca. 43 live per trial species. were homogenous over barrier, though gudgeon significantly smaller than goby or bullhead. distinct enough predict with random forest machine learning approach (92.16% accuracy 85.24% goby). revealed exhibited increased, varied, speeds straighter paths at higher water discharge. These results suggest that passage prevented 130 L/s discharge, whereas bullhead pass barrier. Our findings open new avenue research hydraulic constructions conservation.