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Kadet Trench SAC


The Kadet Trench is a trench system with depths of up to 32 m cutting into the Darss Sill, through which some 70 percent of the water exchange takes place between the North Sea and the Baltic Sea. Together with the Fehmarn Belt, the trench system is important to the population interchange of marine species and is of key importance in supplying the Baltic Sea with oxygen-rich, higher-salinity water from the North Sea.


Fact sheet for Kadet Trench SAC
(In German)
Kadet Trench
EU-Code: DE 1339-301
(In German)
Coordinate of Centroid:
12°15'00" E 54°30'00" N
Habitat types Reefs ca. 23 km²
Species/Population Harbour porpoise
(Phocoena phocoena)    
> 10

Boundaries of the SAC

Sea anemone are at the limit of their distribution range here. Photo: D. Schories (BfN)
Photo: Sea anemone are at the limit of their distribution range here. Photo: D. Schories (BfN)

The boundaries of the roughly 100 km² protected area with depths from 18 m to 32 m mainly correspond to the locations of reef habitats. Several areas of reef protrude from the Darss Sill into the trench proper. Boulder fields characteristically support growth of large algae and mussels. The stone reefs are overgrown to depths of 18 m with brown algae, notably sugar kelp. Red algae are found down to depths of 24 m. This is unusual for the southern Baltic Sea and requires good and constant light and oxygen levels. Mussels are widespread and populate the boulders in large numbers.


Mussels (Mytilus edulis). Photo: Hübner/Krause (BfN)
Photo: Mussels (Mytilus edulis). Photo: Hübner/Krause (BfN)
Overgrown boulder. Photo: Hübner/Krause (BfN)
Photo: Overgrown boulder. Photo: Hübner/Krause (BfN)

The area mostly owes its special ecological value to the structural diversity of the reef habitats. These and in part still heightened salinity levels allow it to be colonised by highly species-rich benthic fauna with the largest share so far of Red List species of any comparable SAC in the German Baltic Sea.

Harbour porpoise are regularly found in the area and its surrounding waters, or traverse it on migration. They are included in the conservation objectives as a Habitats Directive Annex II species. Although none have been spotted in aerial surveys, harbour porpoise are known to frequent the Kadet Trench from porpoise click detector (POD) data.

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 and morphodynamics
  • Maintenance of the unobstructed exchange of North Sea and Baltic Sea water and of the area’s connecting function for ecosystems of the western and central Baltic Sea
  • Maintenance and restoration at favourable conservation status of habitat type Code 1170 (reefs) together with its characteristic and endangered ecological communities and species
  • Maintenance and restoration at favourable conservation status of the harbour porpoise, a Habitats Directive Annex II species, and its natural habitats (among other things under the ASCOBANS Recovery Plan for Harbour Porpoise in the Central Baltic)

Sugar kelp (Laminaria saccharina) at depths of up to 24 m. Photo: Hübner/Krause (BfN)
Photo: Sugar kelp (Laminaria saccharina) at depths of up to 24 m. Photo: Hübner/Krause (BfN)
Cod (Gadus morhua). Photo: S. Gust
Photo: Cod (Gadus morhua). 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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