Marshes in Asköviken-Tidö nature reserve
View from Söderfjärden nature reserve


  • Country: 
  • Site number: 
  • Area: 
    12,251 ha
  • Designation date: 
  • Coordinates: 
    59°28'N 16°39'E
Materials presented on this website, particularly maps and territorial information, are as-is and as-available based on available data and do not imply the expression of any opinion whatsoever on the part of the Secretariat of the Ramsar Convention concerning the legal status of any country, territory, city or area, or of its authorities, or concerning the delimitation of its frontiers or boundaries.


Asköviken-Sörfjärden consists of two sizable bays of Lake Mälaren and an archipelago of some 160 islands and isles between them, which together are representative of a near-natural wetland type (freshwater lake and permanent marshes) in the EU Boreal region. The site supports more than 20,000 waterbirds and more than 1% the biogeographic population of the bean goose Anser fabalis. The shallow bays are important spawning and nursery grounds for a number of fish species and are also important for foraging birds. The Site supports several rare or commercially important fish species including the eel Anguilla Anguilla and the European pike-perch or zander Sander lucioperca. Mälaren is one of the few lakes in Sweden that harbours Vimba vimba. More than 75 globally and nationally red-listed species are present, including birds, fish and molluscs, fungi, moss and lichen, and insects. The Site has hosted human settlements from the 11th century, and a 17th century royal shipyard in the archipelago encouraged the cultivation of oak trees. The Site has high ornithological, recreational, touristic, historical, and educational values. Lake Mälaren is used as a drinking-water reservoir, for fishing, and for the transport of goods.

Administrative region: 
Västmanland and Södermanland Counties

  • National legal designation: 
    • EU Natura 2000 SCI/SPA (1) - Asköviken-Tidö
    • EU Natura 2000 SCI/SPA (2) - Ridöarkipelagen
    • EU Natura 2000 SCI/SPA (3) - Ridö-Sundbyholmsarkipelagen södra
    • EU Natura 2000 SCI/SPA (4) - Söderfjärden
    • EU Natura 2000 SCI/SPA (5) - Lindön
    • Nature reserve (1) - Asköviken-Tidö
    • Nature reserve (2) - Ridö-Sundbyholmsarkipelagen (North)
    • Nature reserve (3) - Ridö-Sundbyholmsarkipelagen (South)
    • Nature reserve (4) - Sörfjärden
    • Nature reserve (5) - Lindön
    • Riksintresse (Site om importance for nature conservation) - 4 sites covering almost the whole Ramsar site
  • Regional (international) legal designations: 
    • EU Natura 2000
  • Last publication date: 


Ramsar Information Sheet (RIS)

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