In July and August 2022, a man-made environmental disaster occurred in the Oder River: a mass die-off of fish, mussels and snails that started in the Polish section of the Oder and then continued downstream until it reached the border Oder. Researchers estimate that up to 1,000 tonnes of fish were lost.
The immediate cause of their death was a toxin-producing (planktonic) brackish water alga, scientifically known as Prymnesium parvum, which was able to grow en masse due to high salinity, high solar radiation, and low water flow.
