Scientists are investigating the reason for a “catastrophic” mass dying of fish within the River Oder, between Poland and Germany, the Guardian reported. Polish scientists have traced excessive salt ranges, however rejected German claims of mercury air pollution, however with each governments suspecting an untraced chemical spillage. German authorities have banned fishing and bathing within the river. Some 2,000 police, 300 firefighters and 200 troopers have been deployed to take away carcasses.