Both reports blamed prymnesium parvum, a type of golden algae whose bloom can emit toxins lethal to fish and shellfish but is not harmful to humans. But they failed to agree on how much fault rests with humans.
[...]
According to the German report: "The most probable cause of the fish kill in the Oder River is a sudden increase in salinity, which, together with other factors, led to a massive increase in a brackish water alga that is toxic to fish."
[...]
The authors of the Polish report named a combination of natural and human factors, and argued they were unsure of the amount of polluted water discharged into the river [from the Baltic Sea? nah. IT'S CONTAINED.]. Under Polish law, water discharges can be legal under conditions set by so-called water permits [!].
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In a report published this week, NGO Greenpeace blamed the fish kill on salt discharges from the Polish mining industry, based on the results of water and soil samples taken by activists at the end of August....

archived personhood status, Sewage in seas, "tuna-like species", floating carpet of dead fish, "tuna bonds", fishing rights row ...