According to WWF the dead zones in the Baltic Sea are growing. 7 of the 10 biggest dead zones are actually found in the Baltic Sea, according to a scientist at the World Resource Institute.
But these dead zones are growing all over the world as research has show that around 4/5ths of the US coast and 2/3rds of Europe’s coasts are threatened by dead zones.

The dead zones occur because of an increase in chemical nutrients in the water. The main “sinners” of this kind of pollution are agriculture, human sewage, urban runoff, industrial effluent, and fossil fuel combustion. The excessive nutrients cause algae blossoms and this in turn makes the oceans (or lakes) depleted of oxygen. In these dead zones all marine life dies.

Sounds like it is time to turn more agriculture into organic farming as organic farming does not produce so much excessive nutrients that can run off into our oceans.