The Southern North Sea is designated a Marine Protected Area. It supports nearly 20% of the UK North Sea harbour porpoise population. In practice, MPA status has meant nothing: bottom trawlers logged more than 37,200 fishing hours inside it in 2025 alone, with no regulatory restrictions on fishing across most of the zone. The designation protects the area on paper while industrial extraction continues uninterrupted beneath the surface. Greenpeace UK's response is blunt physical infrastructure. Activists aboard the Arctic Sunrise dropped large boulders to create an underwater barrier across 116 sq km of the MPA, designed to snag and deter the dragnets used by industrial bottom trawlers. The ship will patrol the area in the coming days to deter other forms of industrial fishing. The group has declared the zone an "ocean park" modelled on national park principles. The scale of industrial trawling in UK MPAs is striking. Greenpeace's analysis found that in 2025, bottom trawlers and dredgers tore through a cumulative 55,600 sq km of MPA seabeds nationally — an area 58 times the size of Dartmoor national park. Less than 1% of UK seas are protected from industrialised fishing in practice, according to Labour MP Kerry McCarthy, who backed the action. The core tension is a governance failure, not an environmental mystery. The MPA designation for the Southern North Sea explicitly aims to protect porpoise populations partly by ensuring prey availability is maintained. Intensive commercial trawling directly contradicts this stated objective. The government has ruled that bottom trawling can continue in English protected waters, making the protection largely symbolic. Greenpeace's boulder tactic is not new — the organisation has deployed similar barriers in other contested marine zones — but it exposes a specific structural gap: the UK has created a legal category (MPA) with no enforcement mechanism attached. The boulders function as privatised enforcement of a public mandate the state has declined to execute. The action was timed to coincide with the national premiere of Blue Planet III, David Attenborough's latest ocean documentary, maximising public attention on the gap between the UK's conservation rhetoric and its regulatory reality. Notable figures including McCarthy added their names to individual boulders. The government has been contacted for comment but has not responded. What this really illustrates is the political economy of marine protection: designating an area "protected" satisfies public demand for conservation while imposing zero costs on the fishing industry. The boulders force a choice the designation was designed to avoid.
