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Adler Ground SAC


Transcript of the Adler Ground SAC video

The approximately 234 km2 Adler Ground protected area encompasses the shallowest parts, i.e. the crest, of Rønne Bank. The Adler Ground consists of a large sandy plateau with central boulder-strewn mounds of glacial till. Its reef areas are the largest and rise closest to the surface of any in the German Baltic Sea EEZ. The boundaries of the protected area are defined by the presence and prominence of sandbank and reef habitats at depths of 7 m to 35 m.


Fact sheet for Adler Ground SAC
(In German)
Adler Ground
EU-Code: DE 1251-301
(In German)
Coordinate of Centroid:
14°15'00" E 54°45'00" N
Habitat types Sandbanks ca. 87 km²
Reefs ca. 110 km²
Species/Population Harbour porpoise
(Phocoena phocoena)    
> 10
Grey seal
(Halichoerus grypus)
Recorded, no current population statistics

Lumpfish on Adlerground

Lumpfish on Adler Ground

Mussels on boulders

Mussels on boulders and sand. Photo: Hübner/Krause (BfN)
Photo: Mussels on boulders and sand. Photo: Hübner/Krause (BfN)
Red algae (Rhodophyceae) growing on blue mussels (Mytilus edulis). Photo: Hübner/Krause (BfN)
Photo: Red algae (Rohodphyceae) growing on blue mussels (Mytilus edulis). Photo: Hübner/Krause (BfN)

In shallow areas at depths of up to about 10 m, the reefs are colonised by large algae such as serrated wrack, sea lace and the red alga Furcellaria lumbricalis.

The deeper flanks (10 to 20 m depth) are dominated by mussels. These colonise boulders and form mussel beds on sand.

Mussels are wonders of nature. From the water taken in through their gills, they extract not only vital oxygen but also plankton and detritus for nutrition. A three-centimetre blue mussel filters about a litre of water through its gills every hour. Any foreign particles carried in the water are kept back by cilia. Food particles are channelled to the digestive tract while suspended inorganic particles are ejected to the top rear of the feeding siphon.

Seabed fauna communities in the sandbank habitat areas are also dominated by a number of mussel species. Characteristic species of the sandy zone deeper than 20 m include Baltic tellin, soft-shell clam and common cockle, along with various rare isopods and amphipods (including Bathyporeia pilosa, Pontoporeia femorata and Saduria entomon).


Eel pout (Zoarces viviparus). Photo: Hübner/Krause (BfN)
Photo: Eel mother (Zoarces viviparus). Photo: Hübner/Krause (BfN)

The reef and sandbank mussel communities provide a key food source for wintering sea ducks, notably long-tailed duck and velvet scoter. The area is also important as a reservoir for recolonisation of deeper surrounding waters with benthic species after episodic mass mortality due to oxygen depletion.

Other Habitats Directive Annex II species recorded are harbour porpoise and grey seal, which are therefore included in the area’s conservation objectives. These species migrate through the area and presumably use it as a foraging ground. Harbour porpoise were first recorded with certainty at the Adler Ground in research surveys from 2002 to 2003. Because of this, it is not yet possible to provide detailed, final information on conservation or restoration objectives or the area’s function for the species.

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 specific ecological functions, biological diversity and natural hydrodynamics
  • Where applicable, restoration to near-natural condition of areas modified by past sediment extraction
  • 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 grey seal

Long-tailed duck (Clangula hyemalis) find ample food here. Photo: S-E. Arndt
Photo: Long-tailed duck (Clangula hyemalis) find ample food here. Photo: S-E. Arndt
Rockpool prawn (Palaemon elegans) on mussels. Photo: Hübner/Krause (BfN)
Photo: Rockpool prawn (Palaemon elegans) on mussels. Photo: Hübner/Krause (BfN)

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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