Wartime explosives litter Danish Wadden Sea but pose little risk, expert says

The seabed off western Jutland remains scattered with thousands of mines, torpedoes, and bombs from two world wars, but the ordnance no longer presents a significant danger to fishermen, according to a maritime warfare expert.

Gert Normann Andersen, director of Sea War Museum Jutland and an experienced wreck diver, described the underwater landscape as “packed with an untold number of mines, torpedoes, bombs, and explosive charges.” German occupying forces laid tens of thousands of coastal mines during World War II, while British aircraft dropped magnetic mines from above. Remnants of downed planes, sunken ships, and submarines—including the German UC-30, a World War I minelayer carrying 18 mines and six torpedoes—still hold live explosives just offshore, visible from land in some cases.

Yet Andersen dismissed concerns over active threats, noting that detonators and batteries have long since degraded. “It’s not particularly dangerous today because all the firing mechanisms are corroded away, and there’s no power left in the batteries,” he told Danish broadcaster DR. While the explosives inside remain as potent as the day they were made, he called current fishing restrictions in parts of the Wadden Sea—enforced by the Danish Emergency Management Agency—”like shooting sparrows with cannons.”

The agency has warned it will report fishermen to police if they violate a decades-old ban on bottom-trawling in a 352-square-kilometer zone, a measure originally tied to safety but now also backed by conservationists. The Danish Society for Nature Conservation has pushed for the restrictions to protect biodiversity, arguing that fine-mesh nets harm non-target species in the ecologically sensitive area.

Andersen advised fishermen who accidentally haul up ordnance to record its location, return it to the seabed, and alert authorities. “Then the police and bomb disposal teams will come and blow it up,” he said.