Natural England - Cold-water coral reefs

Cold-water coral reefs

Most people think that coral reefs are only found in the tropics and are surprised that we have them in our cold seas. Even experts are discovering that the world's oceans contain far more cold-water coral reefs than previously thought.

Cold-water coral reef © JNCC

Cold-water coral reefs can be up to several kilometres long and more than 20metres high. Reefs of this size can be up to 8000 years old; cold-water corals only grow at a rate of about half a centimetre each year.

These reefs are found in deep water, usually from 200 to 400m although they may occur much shallower and very much deeper – to a depth of over 3000m. They form on silt and rock on slopes and underwater mountains rising from the seabed, where there is enough current to bring sufficient food.

Cold-water coral reefs are important because they provide habitats for many other animals including the redfish and squat lobster as well as starfish, sea urchins, anemones and sponges. Cold water reefs also act as breeding grounds for commercially important fish.

Cold-water coral reefs are affected by smothering and marine pollution, which can result from oil and gas operations. The greatest threat to them, however, is bottom trawling. Their slow growth makes them very vulnerable to disturbance.

Brief description of European distribution

Cold-water reefs have a fairly wide distribution throughout the world’s oceans. In the north-east Atlantic they occur off the north and west coasts of Scotland, the west coasts of Ireland, Norway and France, and the north and west coasts of Spain. Cold-water reefs have also been found in the Mediterranean.