Stranding of larval nase (Chondrostoma nasus L.) depending on bank slope, down-ramping rate and daytime

Rapid water level decreases due to hydropeaking are known negatively affect riverine biota, mainly the stranding of organisms in river bank area that becomes regularly dewatered. Even though studies last decades have focused on salmonid fish, also cyprinids may be affected. However, limited knowledge is available this fish family. Therefore, we conducted mesocosm experiments under semi-natural conditions, simulating single events at two different lateral slopes (2% and 5%) with varying down-ramping rates (0.7–3.0 cm min −1 ) during day night. As a response parameter, quantified larval stages (III-IV V) common nase ( Chondrostoma nasus L.). The revealed lower sloped banks exhibited distinctly higher than steeper ones. Daytime similar pattern, more becoming stranded night day, was consistent for all rates. data indicate increased rates, particularly low riverbanks, interaction effects between tested parameters. Overall, study, first time, quantifies consequences flow larvae, revealing differences stages. gained information will, therefore, advance ongoing discussion mitigation by providing deeper understanding artificial sub-daily fluctuations early life cyprinid fish. Our results can inform management policy sharpen existing concepts fine-tune hydropower operations reduce negative ecosystems.