Larger islands are forested and include dry heaths, rich meadows and small mires. There is a strong salt gradient in the area. The site is an important staging area for birds migrating through the Gulf of Bothnia, and supports an abundant variety of nesting waterbirds. There is a bird observatory located at the site. Vanhankaupunginlahti and Laajalahti Bays.
Vegetation includes reed islands, rushes and submerged vegetation and a few forested islands.
The most common breeding waterfowl species at the site are Anas platyrhynchos, A. penelope and Podiceps cristatus . It is also important as a resting area for migratory birds, especially ducks and waders. Human activities include sport fishing and recreation. Posted 23 January 2000, updated 14 December 2000, Dwight Peck, Ramsar.