Greenpeace investigators found that from January 2020 to January 2025, 26 supertrawlers – commercial fishing vessels that measure more than 100m in length and stay at sea for several weeks while catching large amounts of fish and bycatch – spent significant time fishing in 44 of the UK’s offshore Marine Protected Areas (MPAs).

As part of their investigation, the Greenpeace team used Automatic Identification System (AIS) tracking data from Global Fishing Watch for all fishing vessels over 100m to assess the amount of time they spent fishing in UK MPAs from 31 January 2020 to 31 January 2025. 

After assessing the tracking data, the investigators found that, collectively, these large vessels spent 4.2 years, nearly 37,000 hours, fishing in MPAs in the last five years, while, on average, they spent 7,380 hours fishing in the UK’s MPAs every year. The majority of these vessels were foreign-flagged, selling most of their catch overseas.

According to Greenpeace, all of these supertrawlers were operating legally ‘despite the UK government having had the power to ban supertrawlers from operating in our waters since leaving the EU’, revealing that, while the MPAs are protected on paper, more needs to be done to properly grant them the protection they need to conserve habitats and species. 

Erica Finnie, oceans campaigner at Greenpeace UK, said: “The government is failing our protected seas. Marine Protected Areas should be places for fish, marine biodiversity and habitats to rest and recover from the damage caused by human activities. But the government is making a mockery of our MPAs by allowing these places to be routinely fished – despite having had the powers to ban industrial fishing vessels from protected waters since we left the EU.

“By allowing industrial fishing to continue in our protected areas, the government is degrading entire MPAs from the north of Scotland to the south of Cornwall. To be taken seriously as a leader on ocean protection, the UK government must ban supertrawlers, and other types of industrial fishing, from our Marine Protected Areas.”

Marine Protected Areas have been found to boost fish populations significantly. Studies of both the Lyme Bay MPA in the UK and Cabo Pulmo National Marine Park in Mexico found that a whole site approach to MPA protection can boost the abundance and diversity of fish populations by as much as 400%. 

A previous Greenpeace investigation looked at supertrawler fishing hours in MPAs in 2019. This latest investigation provides a fuller view of the situation in the five years since the UK left the EU and comes at a time when the UK’s new Labour government has promised to deliver 30×30 in UK waters.

The relative speed with which Russian flagged supertrawlers left the UK’s MPAs in 2023, shows that it is possible to remove supertrawlers from UK MPAs where there is the political will to do so. 

Supertrawlers can catch hundreds of tonnes of pelagic fish species like herring and blue whiting in a day using enormous nets. Mackerel, one of the key targets for these vessels, has had catch limits set far in excess of scientific advice over the last decade. Due to their size and immense catch capability, supertrawlers also catch large quantities of non-target animals, or bycatch, including dolphins and porpoises as well as sharks, seals and rays. A less-known but equally damaging practice is high-grading, the discarding of low-value catches in order to preserve the quota for high-value fish, which is illegal. 

The new findings further reveal that the majority of supertrawlers fishing in UK MPAs land the vast majority of their catch abroad, giving little economic benefit to the UK. Thereby, supertrawlers’ large-scale and destructive industrial fishing methods affect the health and resilience of the whole marine environment including the fish stocks available to the UK’s small-scale fishing fleet, which does land almost all of its catch in the UK.

Greenpeace UK’s investigation found that only ten MPAs accounted for more than 80% of all supertrawler fishing time calculated between 2020 and 2025, illustrating the immense pressure some MPAs are under. 

Felix Lane, political campaigner at Greenpeace UK, said: “The abject failure to protect our most sensitive marine habitats is a scandal that’s lasted five years too long. The Labour government must now ban destructive industrial fishing in our precious marine environments so it can deliver on its promises to protect 30% of waters domestically. And the government must also follow in the footsteps of the 18 countries, including France and Spain, that have already ratified the Global Ocean Treaty.

“This is the crucial legal tool which can protect 30% of global oceans by 2030. This July the UK also has the power to vote to stop deep sea mining before it starts, preventing a whole new extractive industry that would put pressure on our ocean biodiversity.”

The MPAs which Greenpeace investigators found to be most heavily fished by supertrawlers, in the last five years, were off the coast of Scotland, such as Wyville Thomson Ridge, West of Scotland, Central Fladen, Geikie Slide and Hebridean Slope and Faroe-Shetland Sponge Belt. Pobie Bank Reef, West Shetland Shelf, Seas off Foula, The Barra Fan and Hebrides Terrace Seamount were also highly fished by supertrawlers.

These MPAs were set up to protect precious features like seamounts created by extinct volcanoes, stony reefs and soft corals. They also support important species including crustaceans, deep-sea sponges, great skuas, fulmars, gulls and auks like puffins. 

750,000 people have signed a petition in recent years calling for the UK government to ban supertrawlers and other destructive fishing vessels from the UK’s MPAs, demonstrating long-standing support for the government to act. Banning supertrawlers from fishing in MPAs would help ensure that at least 30% of the UK’s waters, and 30% of the global oceans, are fully protected by 2030 – a scientifically agreed target backed by the UK government. 

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