BlueReef - Rebuilding of Marine Cavernous Boulder Reefs in Kattegat
More than half of Denmark’s nature is covered by the sea. Boulder reefs rising out of the seabed support a very high biodiversity like for example large sea urchins and leather corals.
The main objective of the project is to restore and maintain a favourable conservation status of the offshore reef habitat with its associated species. The projectarea is located at Laesoe Trindel 12 km north-east of the Island of Laesoe.
The project will restore 6,5 ha of marine cavernous boulder reefs and stabilise 6 ha of the existing reef area or effectively double the area of the habitat. The restoration of the submerged reef structures has been carried out with app. 60.000 m3 boulders of various sizes each with a weight of app. 1-6 tonnes. The boulders have delivered blasted in a quarry in southern Norway.
BlueReef is the first large marine nature restoration project in Denmark as well as the first offshore restoration project receiving 50% co-financing from the European Commission. The project budget is Euro 4.8 million and started the 1st of August 2006 and will finish in the spring of 2012.
The BlueReef project has included various elements of assessments prior to the restoration, the restoration activities and a monitoring programme evaluating the success of the restoration effort. It also includes an underwater video and the establishment of an underwater nature trail for divers.
Offshore cavernous boulder reefs in shallow waters have a high biodiversity and is now a rare and yet biological
important natural habitat for a large variety of species like the European Lobster that live in the cracks and crevices between the large boulders. On a national level cavernous boulder reefs in shallow waters have been an
extensively exploited habitat targeted for their high concentration of easy to excavate large boulders suitable for constructing harbour jetties and sea defences. A cautious estimate is that at least 34 km2 of boulders from predominantly shallow cavernous reefs have been excavated from Danish waters or close to 100% of the area of this habitat, leaving an estimated 5 ha untouched.
Laesoe Trindel is a site of European Union community importance and designated as a Natura 2000 Site according to the EU Habitats Directive.
The restored site in Kattegat will provide a significant contribution to maintaining the populations of species which are dependent on the cave-forming boulder reef in Danish waters and function as a crucial steppingstone within a marine corridor linking sites within the Natura 2000 network, as well as being a sanctuary for donor populations.
The project is managed by the Forest and Nature Agency in cooperation with The Agency for Spatial and Environmental Planning, The National Environmental Research Institute and The National Institute of Aquatic Resources.