The Leibniz Institute of Freshwater Ecology and Inland Fisheries (IGB) said on Friday that Prymnesium parvum was identified in all the samples taken from the river recently.

"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," said Elisabeth Varga from the University of Vienna, who led the analysis of the IGB samples.

She said a direct connection between the algae and the death of fish and molluscs in the river could be assumed.