The Archipelago Sea is part of the Baltic sea, and lies between the Gulf of Bothnia, the Sea of Åland and the Gulf of Finland. It has a surface area of around 8,300 km2. The sea contains the largest archipelago of the world in terms of number of islands. However, most of these islands are very small and tightly clustered. The bigger islands are linked to each other by bridges and ferries. The Archipelago Sea is an important source of Baltic herring and rainbow trout, and the sea and its many islands are slowly becoming a larger tourist attraction.