In Sweden, there used to be six reefs of the coral Desmophyllum pertusum in the Kosterfjorden–Väderöfjorden area, in the Skagerrak. Here too, their numbers have declined sharply in recent decades. Today, only two small sites with living corals remain. At the other sites, where we know there used to be corals, there are now only dead coral remains.
One of these sites is Säcken, where 400 small to medium-sized living colonies were discovered in 1999. On a return visit in 2014, only 50 of these were still alive. The reef has now shrunk even further, and only a few small living sections of the reef remain.
There is also a coral reef near the Väderöarna islands. It was classified as extinct after only dead coral structures had been found during surveys between 1995 and 1999. However, in 2013, many small living colonies were discovered.
Unlike most other extinct sites, where only dead coral gravel remained on the seabed, here there were still slightly larger clumps of dead coral skeleton left. New corals had established themselves on these. This indicates that the coral needs a solid, hard substrate with a suitable structure to attach itself to, and that it needs to protrude slightly from the seabed.
Within this project we have developed artificial reefs, that through their surface composition and shape will facilitate larval settlement. The aim is to restore living coral reefs; however, a full recovery will take a long time. If we succeed, this could lead to an increase in the number of fish and other organisms that thrive in coral reefs.
