At Aquidauana, pantanal region of the Mato Grosso do Sul state, shoals of painteds, pacus, golden fishes, cacharas - and even stingrays, are floating dead in Rio Negro, one of the largest in the Amazon River basin.
The estimated Environmental Policy is of that several tons of fishes died, adding that the authorities and experts, they still do not have the scale of the ecological disaster.
Biologist of the State Institute of the Environment, Robert Gill Machado, noted the phenomenon, considered of great proportion, after flying over the region of sub-basin of Rio Negro. At this place fishing is banned. The area is considered one of the nurseries of fish breeding of the Pantanal.
According to the technicians of the Institute the symptoms that occur in this case are the same symptoms of other instances of the genre. The fish are dying putting their heads out of water trying to obtain air, due to lack of oxygen in the water. This deficiency is due to the large volume of ash produced by burned, which is carried by runoff along riverbeds of the wetland.
However, the idea of blaming the ashes of forest burn has no rationale. The residents of the region, they don't believe in this theory. More probaly the poisoning of water by gases would be generated by decomposing organic matter, a process that, in fact, removes oxygen from water. All very natural to some extent. What is not natural in the region is the volume of fish that died from deadly agent. ...
via Brazil Weird News: Brazil - Thousands of dead fish in the Pantanal.