Greenpeace activists have dropped boulders in the North Sea to snag the dragnets of industrial trawlers fishing in a marine protected area.

Activists onboard the Greenpeace ship Arctic Sunrise dropped the giant stones to form an underwater barrier around the Southern North Sea marine protected area (MPA) – the UK’s most bottom-trawled MPA.

Boulders were loaded on to the Arctic Sunrise in Le Havre. Photograph: Andrew McConnell/Greenpeace

The Southern North Sea is an area of importance for harbour porpoises , supporting nearly 20% of the UK North Sea population . But despite its MPA status, there are no restrictions on fishing in most of it.…