Thousands of dead fish are floating in the Oder River, which flows through Germany and Poland, raising fears of an environmental “disaster” as locals are told to stay away from its waters.

The dead fish that appeared on the surface of the river near the German town of Swett was probably brought there by the current from Poland, where the first such cases were recorded by local residents and fishermen as early as July 28.

German officials, surprised by the massive appearance of dead fish, accused the Polish authorities of not informing them.

In Poland, the right-wing populist government is also being criticized for not reacting sooner.

Prime Minister Mateusz Morawiecki tried to justify himself yesterday, Friday: “At first we all thought it was just a local problem,” he said in his weekly podcast.

“The scale of pollution is very large, large enough to say that Oder will take years to recover,” he admitted, however.

“A huge amount of chemical waste was probably dumped into the river, with full awareness of the danger and consequences,” he added.

German Environment Minister Steffi Lemke, for her part, demanded a comprehensive investigation into the causes of this “environmental catastrophe”.

“Deeply shocked”

Standing on the bank, Michael Tutenhahn, Deputy Director of the Lower Oder Valley National Park, looks desperately at the river that forms the German-Polish border.

“We are on the side of Germany. We have dead fish everywhere,” he told AFP.

“I am deeply shocked… I have the impression that I see the destruction of decades of work (…) Water is our life,” he says, adding that many other aquatic animals, such as mussels, have died.

Fish are “just the tip of the iceberg,” he says.

The Oder is a river that has been considered relatively clean for many years and is home to about 40 species of fish.

Many of them – some a few centimeters long, others almost 40 centimeters – are now floating dead in the river. Sometimes you see some struggling to turn around to swim.

“Unusual” death

According to authorities, the fish was probably poisoned.

Their deaths are “unusual,” explains Axel Vogel, Minister for the Environment of the state of Brandenburg, saying that “tons” of fish have undoubtedly already been lost.

He explains that fish deaths are often due to imbalanced oxygen levels when the water level is too low.

“But within a few days, we noticed an increase in oxygen levels, which indicates that a foreign substance got into the water and caused all this,” he said.

In Germany, tests are being carried out to determine the nature of this substance. Authorities have reported evidence of extremely high levels of mercury, which research will need to confirm or disprove.

In Poland, the prosecutor’s office is handling the Oder pollution case, and outrage is growing in the country. The opposition, local authorities and environmental groups are demanding an explanation from the government, some even calling for the resignation of officials in the climate ministry, including the deputy minister who, until Thursday yesterday, urged people to swim in the Oder.

“It’s like Chernobyl when, after the disaster, the Soviet government sent people to participate in the May Day parade,” said environmental activist Daniel Petrievich in an interview with private TV channel TVN24.

On the banks of the Oder in Germany, Tautenhahn expresses concern about the future. “If it’s mercury, then it will stay there for a long time,” he says, pointing out that this metal does not decompose and can remain in river sediments for many years.