More and more dead fish are being found in the Oder. German and Polish authorities continue to search for the cause of the mass deaths.
Update from Thursday, August 18, 10:35 a.m .: Experts assume that toxic algae could be a reason for the massive death of fish in the Oder. Studies by the Leibniz Institute for Freshwater Ecology and Inland Fisheries were able to demonstrate a high density of such algae in the river water, as Jörn Gessler, a scientist at the institute, said in an interview with NDR MV LIVE .
The algae are native to waters with a higher salt content, Gessler explained in the interview. Elevated salt levels have been detected in the Oder since August 5th. Gessler considers it possible that the increased salt levels are due to contamination of human origin. Wastewater from potash mining is one possibility.
Gessler explained that if the algae were the cause of the fish kill, there would be no threat to the Szczecin Lagoon. The salt content there is not sufficient for the algae. However, the researcher emphasizes that this is only a hypothesis so far and that further tests are constantly being carried out.
Almost a hundred tons of dead fish recovered
First report from Tuesday, August 16: Warsaw – Almost a hundred tons of dead fish have so far been recovered from the Oder and the border river Ner. This was announced by the head office of the Polish fire brigade in Warsaw on Tuesday. A large part of the 97.95 tons that have been salvaged so far came from the Oder. But even in the Ner, which is not directly connected to the Oder, more and more dead fish have been found for a few days. The reasons for the fish kill remain unclear.
The natural disaster is also making itself felt in Brandenburg. Helpers also helped there to salvage dead fish from the Oder. The dead animals are destroyed in special incinerators. The size of the amounts recovered in Germany has not yet been announced.
According to Polish authorities, dead fish have now also been found in canals in the south of the city of Szczecin, which are connected to the Oder. The regional administration of the West Pomeranian Voivodeship therefore assumes that contaminated water is moving towards Szczecin. There the Oder flows into the Szczecin Lagoon, a 900 square meter lagoon that is connected to the Baltic Sea.
Authorities are looking for the cause of the fish kill
In the meantime, the Brandenburg State Environment Agency is trying to find the cause of the natural disaster by carrying out laboratory tests on the river water. The first laboratory results now show that the water does not have any increased metal values, but has a high salt and oxygen content, said Sebastian Arnold, spokesman for the Ministry of the Environment, on Tuesday at the request of the German Press Agency . The data from other water samples would be continuously transmitted and evaluated.
In samples from the Frankfurt (Oder) measuring station, which the State Environment Agency publishes on its website, there has been a clear change in various values since last Sunday. The oxygen content, the pH value, the turbidity and other values suddenly went up, while the amount of nitrate nitrogen dropped significantly. The first reports of fish deaths in the Oder appeared on Tuesday. (Nils Tillmann/dpa)