Land animals have been little affected by the mysterious mass fish die-off in the Oder River running along the border between Germany and Poland, a German conservation official said on Thursday.
"The evidence to date indicates that only cold-blooded species are affected, such as fish, mussels and snails," Dirk Treichel, head of the Lower Oder Valley National Park, said. While amphibians and reptiles could also be affected, birds and mammals have been spared.
Christian Wolter, an expert at a hydrology and freshwater fisheries institute in Berlin, said there had been previous cases around the world of fish dying as a result of the algal toxins that had also been found in the Oder.
"There have been no reports in similar disasters that warm-blooded animals have been affected," Wolter said.
The authorities in the German state of Mecklenburg-Vorpommern along the river have lifted a bathing warning issued for the Stettin Lagoon, where the Oder flows into the Baltic Sea. No suspect substances had been found in the fish or the water, they said.
Reports began emerging in Poland at the end of last month of anglers finding dead fish on the Oder banks.
Algal toxins have been found by both the Polish and German authorities, but no definite cause for the die-off has been established amid recriminations on both sides.
Apart from hundreds of tons of fish removed, vast carpets of dead water snail had been observed, Treichel said. Dead mussels were also floating to the surface.
