Greenpeace has created a “boulder barrier” in the North Sea / Activists want to block trawler fishing in a protected area

Greenpeace activists sank huge boulders in the southern North Sea to form an underwater barrier intended to prevent bottom trawling in a protected marine area. The action was carried out from the Arctic Sunrise vessel as a protest against the lack of restrictions on industrial fishing in the United Kingdom’s most heavily exploited marine protected area.

Greenpeace UK claims that the barrier covers approximately 116 square kilometres and blocks access for large vessels. The organisation’s vessel will patrol the area in the coming days to deter other forms of industrial fishing, and the activists have called the region an “ocean park”.

The protected area stretches along England’s east coast, from north of Dogger Bank to the Strait of Dover. The area is important for harbour porpoises, hosting almost 20% of this species’ North Sea population, but for the most part there are no bans on bottom trawling.

According to Greenpeace, these vessels fished for more than 37,200 hours within the protected area in 2025. The organisation says that the activity affects fish populations, harbour porpoises, sharks and seabirds.