What did the fish feel when the fish washed up in the Oder in mid-August and almost all life died?
“Fish have certainly noticed that the water is toxic,” marine biologist Michael Tautenhan says in his office. “Their gills are very sensitive, so if there is poison in there, they will know. Just as we would notice if we came into contact with a toxin. The question is whether they noticed it in time. Some fish have managed to transform into an arm of a river or an inlet or a shoal that has not reached To it the current. They can survive there.”
Tautenhahn believes that fishermen who say fish brains are too small to feel pain say it is just to be able to continue their hobby. Hunters say that only warm-blooded animals can feel pain. I think this is nonsense. I’m convinced that the fish feel pain too, and I can’t prove it.”
Tautenhahn, who received his Ph.D. from the Institute of Fisheries at Humboldt University in Berlin and then East Berlin, is a biologist based in Unteres Odertal National Park, south of the border town of Schwedt. He himself still occasionally hunts, a hobby he started when he was seven years old, but only to eat animals, and not to throw them back. His blue short-sleeved shirt has a fish on it. Sweetened? He points out his belly: “Salmon, trout, sturgeon, and flatfish can also be found in the oder.”
Unfriendly spiny sturgeon glistens behind the glass. But Tautenhahn thinks it’s beautiful.
Tautenhahn nature reserve is shown by jeep. Cranes fly over the reeds, and the eagle over the river. On the other side, which seems more hilly, is Poland. Poisoned fish pose no danger to birds, “the poison has no chance of getting into their stomachs,” Tautenhan says. At the entrance to the river he sits in the mud and catches snail shells from the sand. “Under water is a shell cemetery.”
As of August 9, dead fish washed up on the banks of the Oder out of nowhere. The first report of a bay full of dead fish was soon followed by the next. First, the fishermen brought the dead animals ashore, and later hundreds of volunteers had to help recover the fish. So far, about two hundred tons of fish have been rescued along the German side of the Oder. The researchers assume that this is only a fraction of the total, and that another 800 tons could fall to the bottom of the river.
“The water looks dead,” says Toottenhan, looking down at the river. Usually you can see fish that creep occasionally along the surface of the water while fishing. The river has been slowly recovering since August, and different species have been identified in the river again. But this week the alarm has sounded again: dead fish have drifted ashore in one arm of the Oder. The reason is the lack of oxygen, as a result of the closure of the corridors that had to keep the poison out of the Oder, in addition to the low water level, Brandenburg’s Environment Minister, Axel Vogel (the Greens), said in a statement on Monday. . According to Tottenhan, this is a reasonable explanation but also an optimistic one: “It has not been well researched yet. It would be a disaster if golden algae adapted to less salty conditions.”
Although the investigation will not be completed until the end of September, the hypothesis now is that industrial quantities of salt have been discharged into the Oder River, where it still runs through Poland. “Salt, used in mining,” says Tautenhen. The higher salinity would have led to a massive breeding of golden algae, which does not usually occur in rivers or fresh water. The algae produce prymnesin, a substance that can cause significant fish deaths. Satellite images show a high concentration of chlorophyll, which indicates algae growth.
Read also Huge fish kill in Oder, but what is the culprit?
Cooperation between Germany and Poland in research into fish mortality and how to prevent such an environmental catastrophe in the future is not going well. German Environment Minister Steffi Lemke (the Greens) accused Poland of not sounding the alarm, despite the first dead fish found in Ulawa, hundreds of kilometers from the river, at the end of July. Poland’s Environment Minister Anna Mosowski has accused Germany of the opposite fake news Because the Germans had suggested that the cause was pesticides that had been discharged into the water somewhere in Poland. Both ministers are now arguing over water management. Poland would like to build more canyons in the Oder to speed up the flow and deepen the river for shipping. The river is almost economically important to Germany, and nature managers there see no point in further water exploitation.
dead little sturgeon
Tautenhahn believes that the Polish government does not recognize the environmental disaster out of political expediency: “Our Polish neighbors have become too entangled with fishing. If the government turns out to be wrong, voters will not take it lightly.”
In the Lower Oderal region, politics and nature are in any case close to each other. Under the bridge over the Oder, the Russian oil pipeline Drushba, “Friendship”, enters the country. Along the embankment is a fine iron fence, which is supposed to stop wild boars from Poland, because, according to the German authorities, they bring swine fever with them. “Wild boars can swim very well and the Oder River doesn’t stop them,” says Tautenhan. He explains that the fence also ensured that dozens of roe deer drowned when the water was high and the deer could not get out of the fence.
Since 2007, Tautenhahn and colleagues have been working to reintroduce sturgeon in Oder. To date, 3.5 million people have been expelled. It is still not clear whether the project will be successful or not: sturgeon are sexually mature only when they are twelve to fifteen years old, so the first offspring has not yet come. 20,000 young sturgeon, which grew up in a basin in the Oder, did not survive the wave of poison. “They became apathetic, their nostrils swollen.” The sturgeon were quickly transferred to an inland body of water not in contact with the Oder, said Tautenhan, but it was too late for most of them.
In his office there is a Siberian sturgeon in spirits. Toottenhan says sturgeon lived 200 million years ago and still knew the dinosaurs. The unfriendly prickly animal glistens behind the glass. But Tautenhahn thinks it’s beautiful. “It has a mouth like any other fish. Behold, under its nose is a fin that he can feel and taste in the ground. When a fish or an insect spots it, it releases from its mouth, next to that fin, a kind of stem that sucks everything.”