Environmental campaigners have begun dropping granite boulders into a protected area of the North Sea to stop destructive fishing.
Greenpeace said the inert boulders, which they were spacing at precise intervals inside the Dogger Bank protected area, would not have a significant impact on the seabed but would stop destructive bottom trawling.
This fishing method, in which heavy weighted nets are dragged across the sea floor to catch fish, is destroying the seabed that the protected area designation for Dogger Bank is designed to conserve, Greenpeace warned.
Any bottom trawlers trying to fish over the boulders will get their gear snagged and ruined on the rocks, though passing marine traffic will not be affected.
The shallow sandbank habitat is home to crabs, starfish, flatfish and sandeels which are food for seabirds such as puffins, as well as for porpoises and dolphins.
Environmentalists accuse the Government of failing to properly protect the area, despite its designation as a Special Area of Conservation (SAC), by not fully restricting damaging fishing activity.
Greenpeace also said it had found 11 large fishing vessels operating in the Dogger Bank marine protected area with their automatic identification system switched off – something which is illegal in most situations.
The environmental charity has taken matters into its own hands, using its vessel Esperanza to use granite boulders to create an underwater barrier that closes almost 50 square miles of Dogger Bank from bottom trawling.
Activists plan to continue to place boulders in the area until it is fully protected from the fishing activity, and say they will remove the boulders if the UK Government properly protects the marine reserve.
Chris Thorne, a Greenpeace UK oceans campaigner, said from on board the Esperanza: “Our Government has utterly failed to protect the Dogger Bank, and all our marine protected areas, from destructive industrial fishing.
“How can you continue to allow bottom trawlers to plough the seabed in a protected area designed specifically to protect the seabed?
“Allowing bottom trawling in a protected area established to protect the seabed is equivalent to allowing bulldozers to plough through a protected forest. This must stop.
“Our Government won’t act, and we can’t sit idly by while they allow supposedly protected parts of our oceans to be destroyed.”
Greenpeace said it had commissioned an independent scientific agency, BioLaGu, to conduct an environmental impact assessment that concluded placing the boulders would not have a significant impact on the protected feature of the Dogger Bank.
Activists say they have also informed the relevant marine authorities to ensure navigational safety for mariners in the area.
A spokesperson for the Environment Department said the Government was putting sustainable fishing and protection of the seas at the heart of its future fishing strategy.
They said: “We have already set up a ‘blue belt’ of protected waters nearly twice the size of England, and the Fisheries Bill proposes new powers to better manage and control our marine protected areas and English waters.
“The Common Fisheries Policy currently restricts our ability to implement tougher protections, but leaving the EU and taking back control of our waters as an independent coastal state means we can introduce stronger measures.”