A significant overgrowth of toxic algae, which is linked to industrial pollution, is the most likely reason a huge number of fish died in the river Oder, the Leibniz Institute of Freshwater Ecology and Inland Fisheries (IGB) said on Friday.
Since late July, tonnes of dead fish died in the river that flows along part of Germany’s border with Poland. IGB said that Prymnesium parvum was found in all the samples taken from the river.
“When this specific type of algae is present in very large quantities, as is the case in the Oder samples, very high toxin concentrations must also be assumed,” Elisabeth Varga from the University of Vienna, who analyzed the IGB samples, said.
There’s likely a direct connection between the algae and the death of fish and molluscs in the river, Varga said.
IGB said in a statement that research is still needed on the toxicity of the algae, and that it is not clear whether humans and other animals could also be affected.
Polish Climate Minister Anna Moskwa said that more research would be needed to determine why the algae appeared. “We see that it rarely appears in the world,” Moskwa said at a news conference.
Industrial pollution is most likely the cause of the enormous growth of algae, IGB scientist Tobias Goldhammer said. Industrial pollution raises salinity levels in the water, which causes algae growth.
If nothing is done to decrease salt levels, such toxic overgrowths could occur again, Goldhammer added.