Stones have been ‘overfished’ from the sea – here’s how Denmark’s rocky reefs are being restored

A seaweed garden: rocks provide vital surfaces for marine life to grow. Dominique Townsend, CC BY-NC-ND

At the end of the last ice age, billions of boulders and cobbles were left scattered over southern Scandinavia. Huge ice sheets had dragged the rocks from mountainous regions further north down to the Baltic Sea areas. When those ice sheets retreated and sea levels rose, these colossal boulders became rocky reefs, rich with marine life. These rocks formed part of a naturally resilient coast...