Hydropeaking on fish physiological stress

Research on impacts of hydropeaking on river ecosystems has increased in the last years. For fish, much literature reports stranding and behavior changes, but physiological stress is less understood. In this study, we simulated a natural-flow scenario and five hydropeaking operating scenarios varying in frequency, duration and fall rate of the inundations, and water velocity and level in our Greenchannel facility, which is a mesocosm of fluvial ecosystem. 15 different rainbow trouts (Oncorhynchus mykiss) each time were subject to a scenario during 24 hours, measuring several physiological parameters at the end of the trials: Cortisol, CPK (Creatine Phosphokinase), LDH (Lactate Dehydrogenase), Triglycerides, Lactate, NEFA (Free Fatty Acids) and skin color. Results show how levels of these parameters change significantly in response to higher intensities of hydropeaking, which may lead to bad performance or death in the long term.