The Great Barrier Reef of the North

The Oresund is a huge natural treasure with its unique environment.

For decades, bottom trawling where a funnel-shaped fishing net is dragged across the sea bottom by a fishing vessel has been prohibited in the Oresund. This has led to an unusually varied life in the sea with a multitude of healthy fish.

The Oresund is a quite extraordinary area, as the salty waters of the Kattegat meet the fresh waters from the Baltic Sea right in this area. This causes strong currents and a sea bottom teeming with life, cold-water corals and gammarus colonies.

For this reason, the unique underworld of the Oresund is called ”The Great Barrier Reef of the North” by the researchers at Øresundsakvariet (The Øresund Aquarium).

At a depth of 30 meters, off the Swedish town Råå, Oresund’s coral reef, Knähaken, is located, covering around 1366 hectares. It was turned into a marine reservation by Sweden in 2001. The stable saline and temperature conditions have caused abundant underwater fauna in Knähaken. The coral reef is home to a variety of fish species, including sexually mature cod. There are also mussel beds and the occasional big echinoderms. You can read more about the fauna of the coral reef here.

Be aware that the area is not suitable for diving due to strong currents and the depth at the coral reef.

The coral limestone that is found in the Oresund is a very porous type of rock. This means that it is capable of containing liquids and gasses such as oil and natural gas. Extraction of raw materials in the Oresund may have major consequences for the wildlife and fish life in the Sound, and that is why several organisations are currently working on saving the Oresund’s unique underwater life for the future.

Sources: Øresundsakvariet, Øresundsvandssamarbejdet (The Sound Water Cooperation) and Geocenter.dk (website in Danish)

Picture: Øresundsakvariet / Kasper Nyberg. 

Coordinates:  Latitude: 55.961230
Longitude: 12.613576