Sea and archipelago

The beautiful archipelago and sea areas of Espoo are not only important recreational destinations – they are also home to numerous animal and plant species. The most lush marine nature can be found in sea meadows, flood plain forests and shallow bays. In flood plain forests, water level rises on a regular basis, completely covering the ground vegetation and the roots and trunk bases of trees. Shallow bays, on the other hand, slowly become filled with reeds and other vegetation. Seaside meadows and natural beaches are rare, which is why they are protected under the Nature Conservation Act. In addition, several of the outer islands off Espoo have islets that are protected for the duration of seabirds’ nesting season. You can also spot grey seals or even Baltic ringed seals resting on the islets.

The inner bays in the Espoo area are important spawning and fry areas for several species of fish. The fish fries of the pikeperch, the perch and the smelt are the most abundant in the sheltered bays of Espoonlahti. The trout, the flounder and other more marine species, on the other hand, are prevalent in the southern parts of Espoonlahti.

The beautiful archipelago is easy to explore, either by yourself or in the summertime on board the archipelago boat. More information is available on the webpage  Recreational islands.

Espoo's marine nature is diverse, even below the surface. Espoonlahti and Laajalahti have been recognised as underwater marine nature areas that are ecologically significant on a national level. Espoonlahti has abundant and diverse aquatic vegetation and distribution areas of the leaf beetle species Macroplea pubipennis. Both bay areas are also important breeding areas for different species of fish, and they are significant for migratory fish.

The sea areas of Espoo have been surveyed as part of The Finnish Inventory Programme for Underwater Marine Diversity VELMU(external link, opens in a new window) (in Finnish) and the joint Meriluonto 2021 campaign of the City of Espoo and the City of Helsinki. In addition to Espoonlahti and Laajalahti, these surveys have identified seven other locally ecologically significant underwater marine nature areas, which are Otsolahti, Nuottalahti, Miessaarenselkä, Lilla Bodö–Stora Bodö, Kaparen–Rövaren–Stora Herrö, Knapperskär–Gåsgrund–Alskär and Kytö– Norra och Södra Kytökäringen. You can find the areas in the VELMU map service(external link, opens in a new window) (in Finnish). The areas recognised in the surveys are significant because they are diverse in species. They also have some key species such as the bladderwrack, the eelgrass and the bay mussel. Key species play an essential role in the survival of many other species and they are important in maintaining a diverse range of species. 

Like the rest of the Baltic Sea, the marine areas in Espoo suffer from eutrophication. The more visible signs of eutrophication include blue algae blooms, water clouding and slime build-up. Espoo has been involved in the Baltic Sea Challenge(external link, opens in a new window) since 2008. The Baltic Sea Challenge is an international network focused on water conservation and it is open to all actors. It aims to implement concrete water conservation measures to improve the condition of the Baltic Sea. 

Good results have been achieved in the protection of the Baltic Sea, but improving the condition of the Baltic Sea will continue to require further measures. Espoo’s latest Baltic Sea Action Plan includes the city’s measures for protecting the Baltic Sea in 2024–2028. The programme includes measures with which Espoo will reduce the nutrient load, emissions of harmful substances and littering in its sea area.