Hydropeaking Affects Fish Reproduction in Rivers

The so-called hydropeaking, i.e. discontinuous flow changes in rivers, significantly disrupts fish reproduction. In the current study, scientists from the Institute of Hydrobiology of the Biology Centre of the Czech Academy of Sciences focused on how hydropeaking affects the spawning asp shoal in the Želivka River. The local asp shoal, protected under the Natura 2000, faces unpredictable water current changes.

hanks to the daily manipulation of water discharge in rivers, when water is first retained and then discharged from the dam, the energy potential of the river can be used for demands of hydropower plants or watersport races. However, the so-called hydropeaking significantly disrupts river life and negatively affects fish. "During low peak, fish eggs can be dried out or fish stranded on the bare bottom. Contrarily, during high peak, a strong current can carry away and degrade eggs, in extreme cases fish larvae, and even adult fish," explains Daniel Bartoň, the first author of the study and a doctoral student at the Institute of Hydrobiology BC CAS.

Hydrobiologists from the Biology Centre of the Czech Academy of Sciences investigated how the changing current affects spawning adults of asp - large carp predator at the Švihov Reservoir on the Želivka River. Here, the largest asp shoal in the Czech Republic gathers every year, which is also one of the reasons why this unique locality stands on the list of protected areas within the Natura 2000 system.

Publication: Bartoň D, et al., Hydropeaking affects fish reproduction in rivers, Biology Centre CAS (2023). DOI: 10.1016/j.scitotenv.2021.150649.

Original Story Source: Czech Academy of Sciences