The Bothnian Bay is located in the northernmost part of the Baltic Sea, with an average depth of 40 meters and its deepest point reaching further than 100 meters. An archipelago, consisting mainly of sand and gravel islands lies in the north, while the south of the bay boasts a rocky coast and bedrocks. Relatively rapid land upheaval, of approximately 9 mm a year, occurs particularly on the Finnish side of the bay. The Bothnian Bay is frozen on average 170 to 190 days a year and large freshwater rivers run into it, keeping salinity low, at around 3.5 psu.
This area is in a relatively healthy status, as it is not suffering from eutrophication, and has good oxygen levels even in the deeper areas, unlike most of the Baltic Sea, where anoxic bottoms are common due to eutrophication.
Oceana studied the deeper parts of the Bothnian Sea in 2011 and 2012 using an ROV. Saduria- and Monoporeia communities were documented, both earlier listed as threatened by HELCOM.
At current there are no signals from Swedish government to protect this area.
