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Hayes, DS; Auer, S; Fauchery, E; Graf, D; Hasler, T; Mameri, D; Schmutz, S; Fuhrer, S.
(2023): The interactive effect of river bank morphology and daytime on downstream displacement and stranding of cyprinid larvae in hydropeaking conditions
ECOHYDROL HYDROBIOL. 2023; 23(1): 152-161. FullText FullText_BOKU

Downstream displacement and stranding of fish are key impacts in hydropeaked rivers, adversely affecting the organisms and, subsequently, the population. While these phenom-ena have been extensively studied for salmonid fish, few studies have been conducted on cyprinids, particularly at heterogeneous river banks that provide nursery areas for the ear-liest life cycle stages. This study examines the effects of rapid flow decreases (i.e., down-ramping) on downstream displacement and stranding of common nase, Chondrostoma na-sus, larvae at two river bank morphologies (a flat gravel bar and a heterogeneous river bank consisting of a sill and ditch) and daytime periods (day and night) in a mesocosm fa-cility. For a subset of the sill and ditch experiments, stranding location was noted to quan-tify the trapping effect of the structure. The results show that nase larvae's downstream displacement and stranding rates were higher at the sill and ditch than at the flat gravel bar. In addition, the effects of down-ramping were more visible at night than during the day. The displacement and stranding rates were the highest for the sill and ditch structure at night. In this case, the stranding rate was four times higher in the ditch area compared to other available areas of the mesocosm. Riverbank depressions can increase the strand -ing risk when disconnected and dewatered from the main channel after down-ramping, constituting potential ecological traps for fish larvae. These findings highlight the need to integrate riverbank morphology and flow schemes in hydropeaking mitigation frameworks to reduce fish displacement and stranding risks.(c) 2022 The Author(s). Published by Elsevier B.V. on behalf of European Regional Centre for Ecohydrology of the Polish Academy of Sciences. This is an open access article under the CC BY license ( )
Authors BOKU Wien:
Auer Stefan
Führer Simon
Graf David Ruben Max
Hasler Thomas
Hayes Daniel S.
Schmutz Stefan

Find related publications in this database (Keywords)
Pulsed flows
Flow ramping
Environmental flows
Ecological trap
Odds ratio

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