Hanko Peninsula, located at the entrance to the Gulf of Finland, is the southern-most part of the Finnish
mainland and boasts an archipelago and long sandy beaches. Salinity is relatively low, ranging from 5.5 to 7.5 psu, and the waters in the shallower coastal areas are limnic. Upwellings, a common occurrence in the area wherein nutrient-rich sediments are brought up to the surface, cause a rapid increase in the salinity in areas at 35 meters, and a small increase in salinity in the surface water. The inner waters of the archipelago freeze every year, while the more open waters freeze regularly, but not every winter. Low salinity limits the amount of marine species in the area. Species composition changes completely from the open waters to the coast; with marine species being more common further from the coast and limnic species getting more common closer to the shore. Other factors, like visibility, exposure to waves and ice, also affect the species composition. In the area around Hanko Peninsula, both true marine species, such as bladder wracks (Fucus vesiculosus) and cod (Gadus morhua), and true freshwater species, including pond weed (Potamogeton perfoliatus) and pike (Esox lucius), exist.
The Hanko Peninsula hosts a number of important species and habitats, including feeding and spawning
grounds for many species of fish. The current marine protected area (Natura 2000 area) covers mainly only shallow waters leaving the deeper parts outside of the protection area. Based on data gathered over the course of Oceana’s two expeditions in 2011 and 2012, Oceana is proposing an expansion of the already existing Natura 2000 site, to cover both the shallower waters, which have blue mussel beds, and the deeper parts, which are home to the Macoma and Saduria communities.
Finland has submitted this proposal to EU and the enlargement will be officially protected. Oceana is following the process closely.
