When we think of underwater reefs, our minds wander to tropical coral wonderlands, but chilly Scotland has reefs of its own. In fact, one reef, which hosts millions of distinctive clams, is the largest of its kind in the world. At least it was, until a dredging boat did extensive damage that may take decades or centuries to restore. If there is one scrap of comfort to this, it is that the disaster has caused the reef to be studied and its scale to be revealed.

The story began back in April, when a scallop dredger in Loch Carron, western Scotland, was found to have dragged its dredging gear through the reef twice, doing serious damage. Fishing in the Loch was immediately banned while efforts began to assess the consequences. In the process, divers learned about the nature of the reef itself.

The bed of the Loch is filled with as many as 250 million flame shells, a species of saltwater bivalve that looks like it used to drum for the Muppets before going aquatic. It once lived in huge quantities off the Scottish west coast, but large beds are now rare, in large part because of dredging like this. Other seabed creatures, such as sea urchins and spider crabs also abound. The dredging was legal at the time, but outrage led to a temporary ban on operations within the Loch, which may now be made permanent.

 

Meanwhile, Scottish Natural Heritage divers started to explore the reef like never before, revealing its true size. Until this work was done, a 100-million-scallop bed in neighboring Loch Alsh was thought to be the largest of this type, not just in Scotland but in the world. However, the Loch Carron reef is two and a half times larger.

Besides the environmental value of the area, sustainable harvesting by scallop divers has made the Loch commercially important, something that will be greatly harmed by the dredging. Scallop dredging does not just capture target species, it also rips other animals and algae from their place on the sea floor, often leaving them to die.

The dredging set off a heated debate over whether this method is ever appropriate for scallop harvesting, and if so when. The discovery of the reef's size will intensify this. The BBC has quoted Scottish Environment Secretary Roseanna Cunningham as saying; "This is an astonishing find and I think that we would be completely remiss not to take notice of it and to do what we can to protect it.”