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Fehmarn Belt SAC


The roughly 280 km2 protected area encloses the narrow German EEZ north of Fehmarn containing the Fehmarn Belt trench. This is a strait with depths of up to 35 m through which about 70 percent of the water exchange between the North Sea and Baltic Sea takes place, making it of key importance for the movement and interchange of marine species.

The boundaries of the protected area (with water depths from 12 m to 35 m) are mainly determined by the presence of sandbank and reef habitat types and by the distribution centres of harbour porpoise.


Fact sheet for Fehmarn Belt SAC
(In German)
Fehmarn Belt
EU-Code: DE 1332-301
(In German)
Coordinate of Centroid:
11°14’00" E 54°34’00" N
Habitat types Sandbanks 5 km²
Reefs 57 km²
Species/Population Harbour porpoise
(Phocoena phocoena)    
> 100
Common seal
(Phoca vitulina)
No current population statistics

Megaripples of great ecological value

Sea squirts (Ascidiacea) and red algae. Photo: Dirk Schories (BfN)
Photo: Sea squirts (Ascidiacea) and red algae. Photo: Dirk Schories (BfN)
Gooseberry sea squirts (Dendrodoa grossularia)). Photo: Dirk Schories (BfN)
Photo: Gooseberry sea squirts (Dendrodoa grossularia). Photo: Dirk Schories (BfN)

A distinctive feature of the southern Fehmarn Belt is an area of huge sand ripples. These ‘megaripples’ rising up to three metres from the sea bed are a special form of the sandbank habitat type and are of great geoscientific and ecological value because of their scarcity. How they arise is not yet fully known. They are colonised by closely heterogeneous benthic communities whose characteristic species include astarte and ocean quahog bivalves.


Goldsinny (Ctenolabrus rupestris) among red algae. Photo: D. Schories (BfN)
Photo: Goldsinny (Ctenolabrus rupestris) among red algae. Photo: Dirk Schories (BfN)

The reefs in the area shelter some of the most species-rich ecological communities in the Baltic Sea. A distinguishing feature of the Fehmarn Belt reefs comprises large populations of brown and red algae to depths of over 20 m. The benthic communities at home on the rocky substrate encompass a great diversity of species, dominated by sponges and bivalves. These include some highly sensitive organisms (including a range of crustaceans) and some very long-lived fauna such as common and red whelk, indicating constant favourable environmental conditions.


Gapers (Mya ssp.), a characteristic species. Photo: D. Schories
Gapers (Mya ssp.), a characteristic species. Photo: D. Schories
Dense algae growth down to depths of 30 m. Photo: Hübner/Krause (BfN)
Photo: Dense algae growth down to depths of 30 m. Photo: Hübner/Krause (BfN)

Researchers have recently discovered species in all major groups that have not been recorded in the Baltic Sea for years or even decades. Among them are a large number of the benthic organisms in the Red List of German Baltic Sea species.

Harbour porpoise migrate across Fehmarn Belt on a regular basis, and very frequently for Baltic Sea standards. They are found both within the designated site area and in neighbouring waters around Fehmarn. The site appears to be important to the species, notably in resting periods. Calves have also been sighted. Harbour porpoise in the German Baltic Sea have been censused since 2002 in aerial surveys by the West Coast Research and Technology Centre (FTZ) and are registered acoustically with porpoise click detectors. Danish researchers have also traced porpoise migrations into Fehmarn Belt.

Another Habitats Directive Annex II species covered by the conservation objectives for the site is the common seal, for which the site is a feeding ground.

Conservation objectives

General conservation objectives have been set as follows for the habitat types and species by which the site is defined:

  • Maintenance and restoration of the site’s biological diversity, natural hydrodynamics and morphodynamics, and specific ecological functions, including:

    • As a corridor for the unobstructed exchange of aperiodically inflowing salt water from the North Sea and outflowing brackish water from the Baltic Sea
    • As a main migration route for marine flora and fauna in the eastern Baltic Sea;

  • Maintenance and restoration at favourable conservation status of habitat type Code 1110 (sandbanks which are slightly covered by sea water all the time) and habitat type Code 1170 (reefs) together with their characteristic and endangered ecological communities and species
  • Maintenance and restoration at favourable conservation status of the following Habitats Directive species and their natural habitats: Harbour porpoise (among other things under the ASCOBANS Recovery Plan for Harbour Porpoise in the Central Baltic) and common seal

Ideal habitat for sand goby (Pomatoschistus minutus). Photo: Hübner/Krause (BfN)
Photo: Ideal habitat for sand goby (Pomatoschistus minutus). Photo: Hübner/Krause (BfN)
Thornback skate/ray (Raja clavata). Photo: S. Gust
Photo: Thornback skate/ray (Raja clavata). Photo: S. Gust

Natura 2000 sites in the German Baltic Sea EEZ:

 

Baltic Sea

Fehmarn Belt

Kadet Trench

Adler Ground

Western Rønne Bank

Odra Bank

Pomeranian Bay

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