Author(s): Cumhur Ozbey; Serhat Kucukali; Baran Yogurtcuoglu; Ahmet Alp

Linked Author(s): Serhat Kucukali

Keywords: No Keywords

Abstract: The presence of hydropower plants in river ecosystems has a negative impact on downstream migrating fish species by either partially or completely restricting their movements. Although angled bar racks are increasingly employed to direct fish at water intakes, their effectiveness for potamodromous species during downstream migrations remains inadequately quantified, especially across different structural configurations. This study experimentally examined the behavioural responses of fish to hydraulic conditions using the Oppermann fine screen, both with and without an elliptical guidance wall. The experiments were performed at a 45° screen angle, with a bar spacing of 10 mm, for two potamodromous fish species, the Colchic nase (Chondrostoma colchicum) and the Sakarya bleak (Alburnus escherichii). Results indicated that the guidance wall markedly increased passage success for Alburnus while positively influencing passage trends for Chondrostoma. Total body length was identified as a highly significant predictor of success for Chondrostoma, whereas it was not for Alburnus. Consequently, incorporating fish length into predictive models significantly enhanced their classification accuracy (as indicated by AUC) for Chondrostoma.

DOI:

Year: 2026