Evaluation of Low-Head Ramped Weirs for a Potamodromous Cyprinid: Effects of Substrate Addition and Discharge on Fish Passage Performance, Stress and Fatigue

Requalification of low-head ramped weirs through the addition substrates (retrofitting) has attracted attention in recent years. However, few studies are available on how this measure affects negotiation by fish. This study aimed to assess performance an experimental weir (3.00 m long with 10% slope; 0.30 head-drop) enhance passage a potamodromous cyprinid species, Iberian barbel (Luciobarbus bocagei). Attention was given testing effects substrate, case cobbles, ramp (Nature) vs. smooth bottom (Control), and discharge (Q; 55 L·s?1 110 (or specific per unit width, q = 92 L·s?1·m?1 183 L·s?1·m?1)) fish performance. Fish physiological responses stress fatigue, measured glucose lactate concentrations blood samples, were also analysed. Results showed that Nature design generally increased movements successful upstream passages, enhanced enabling faster negotiations. affected increasing discharge, registering reductions L·s?1. parameters indicate both influenced discharge. The outcomes from present important information about across could provide data needed help biologists engineers develop more effective structures alleviate small instream obstacles.