The oxygen deficiency on the bottom of the Baltic Sea is worse than ever, according to the Swedish Meteorological Institute. The dead area on the bottom of the Baltic Sea increased from 5 to 15 percent since 2000.
"With two milliliters of oxygen per liter fish begin to flee the area," says Bertil Håkansson, division head at the Swedish Agency for Marine and Water Management.
Håkansson says the situation is dangerous. Low oxygen levels affect fish, especially sensitive cod.
Sweden has been measuring oxygen levels in the Baltic since the 1960s.