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Tons of dead fish in the Thaya, Czech Republic

Over 40 tons of fish died this summer (2022) in the Thaya in the region of Břeclav. Among the fish carcasses were also sterlets, a protected sturgeon species, with more than 15 individuals reported. However, the total number of dead sterlets remains unknown. The sterlets most likely originated from the release program of the LIFE Sterlet project, which stocked several thousand in the area from 2016-2021. The reason for the mass extinction was apparently a lack of oxygen, caused by mass proliferation of cyanobacteria. Experts state that as long the cyanobacteria have ideal conditions in the water with nutrients like phosphorus and nitrogen in combination with higher temperatures, such mass die-offs are difficult to prevent. Similar events happened in summer 2022 in many regions and won’t remain isolated cases, with regard to climate change and the rise in average temperatures.