Thousands of fish have been washing up in the Rio bay, and researchers aren't sure why.
The extremely polluted bay will host sailing events at the 2016 Olympics, but sailors are concerned because human sewage gets pumped into the waters, The AFP reported.The thousands of rotting fish carcasses that have recently washed up on shore have not helped the appeal of the bay; scientists are confused by the mass deaths, but don't believe the phenomenon is linked to the sewage pollution.
"Tests showed that this is not a matter of chemical or toxic water pollution," Rio do Janeiro State University oceanographer David Zee told the AFP.
A municipal company has removed 20 tons of dead sabalo fish and four deceased sea turtles. Water testing of the region has not detected any toxic chemicals or change in the water's Ph, but fishermen are blaming the deaths on petrochemical activities of Petrobras.
"We want to know why so many fish have died. The rotten smell is horrible and there are many flies on the island. The authorities tell us nothing," said Vilma Leocadio of the Paqueta citizens' association. "We are afraid, we do not bathe in the sea [anymore] and do not buy fish here."
Five of the dead fish were sent to the Federal University of Rio de Janeiro's biology department for analysis, but the results are not expected to return for a week.
Thermal pollution could also be to blame for the shocking rate of fish kill.
"Sabalo are very sensitive to any lack of oxygen. Warm water temperatures such as those recorded several days ago-ranging from 27 to 30 degrees Celsius (81 to 86 Fahrenheit)-in shallow water decrease the solubility of oxygen," Zee said.
The theory makes sense because if the deaths were caused by chemical contamination there would be a massive die off of other species as well.
"We have more questions than answers. We must wait for the results of the analysis," Zee said.
