Starting points and surveys
The starting point of the zone division is the Finnish Environment Institute’s classification of coastal waters (SYKE 2013), in which the coastal waters are classified in 11 classes. The key classification criteria of the coastal water types are salinity of the water, openness of the archipelago, length of the ice winter, water depth, exchange of water (current flow conditions) and fauna in the area. In maritime spatial planning, the open sea zone covers the area outside archipelagos and coastal waters, including the exclusive economic zone (EEZ).