Out of 113 UK marine protected areas designated to protect dolphins, porpoises, whales and seabirds, just 2 ban highly destructive bottom-trawl fishing across the whole site.
Now a new report from Oceana UK has revealed the severe harm bottom trawling can cause these well-loved wildlife species, from entanglement to prey depletion.
One harbour porpoise sanctuary in the North Sea was subjected to over 30,000 hours of apparent bottom trawling last year alone.
A projection stunt cast footage of bottom trawling on to the chalk cliffs of Botany Bay, Kent, demanding real protection for wildlife.
Bottom trawlers drag heavy metal gear and nets, which can weigh several tonnes, across the seafloor, scooping up almost all life in their path. While the direct destruction of seabed habitats has been well documented, this damaging form of fishing also has severe impacts across the marine ecosystem and is rampant in areas designed to safeguard some of Britain’s most beloved wildlife, such as puffins and porpoises Oceana’s new report Trawled and Mauled has revealed.
Currently, there are no UK marine protected areas (MPAs) designated for whales, dolphins or porpoises that are fully protected from bottom trawling across the whole site, and only two for seabirds. This is out of the total 113 MPAs that should be providing safe havens for these species, and only covers an area of sea the size of the Isle of Wight.
The UK Government’s own assessments identify bottom trawling as a threat in 75% of these MPAs, although Oceana UK’s report brings together evidence of harm which indicates that to fully safeguard these species, all MPAs should be entirely free of this destructive type of fishing.
Analysis of satellite tracking shows that one harbour porpoise sanctuary, the Southern North Sea Special Area of Conservation, suffered 30,936 hours of apparent bottom trawling in 2025. Adding up to 1,289 days packed into just one year.
By destroying and disrupting seabed habitats, bottom trawling can cause populations of prey species like sandeels to dwindle. These small fish provide crucial food for whales such as humpback and minke as well as seabirds like the kittiwake.
The heavy equipment also creates underwater noise as it scrapes the seabed and generates clouds of disturbed sediment. This disrupts feeding both for species like dolphins and porpoises that rely on sound to hunt, and seabirds such as puffins and terns, which use sight.
The UK Government has committed to a public consultation on how to manage bottom trawling in five MPAs designated to protect seabirds and cetaceans. Oceana UK’s report highlights that to fulfil their purpose, bottom trawling should be fully banned across these areas, the NGO says.
Hugo Tagholm, Executive Director of Oceana UK, said:
“Our report reveals that the deep harms caused by bottom trawling are not limited to life on the seabed. Harbour porpoises, puffins, terns and countless other animals need healthy habitats and abundant prey. The government simply cannot claim that these areas are protected while allowing destructive trawling inside them.
Areas designated to protect some of our most iconic species are still allowing a destructive activity that the government’s own assessments identify as a threat. This raises a serious question about the credibility of the UK’s marine protection measures and the true extent of its ambitions.
The UK has promised to effectively protect 30% of the ocean by 2030, but there is a risk of bold targets being reduced to little more than blue washing. If we are serious about meeting that commitment, protection must exist in practice not just on paper.”
Professor Emma Sheehan, Professor of Marine Ecology at the University of Plymouth, said:
“Bottom trawling harms seabirds and cetaceans in many ways, directly and indirectly. Animals can become trapped in fishing gear, suffering an agonising death. But many of the impacts occur through changes to the wider ecosystem. Bottom trawling ravages habitats, removes prey and generates intense underwater noise.
“Seabirds and cetaceans sit near the top of marine food webs. Their survival depends on healthy ocean ecosystems. Marine protected areas are designed to conserve vital ecosystems and species and allowing bottom trawling within them undermines the very purpose of their designation.”
The case for banning bottom trawling in MPAs extends beyond the impacts on wildlife. According to Defra, a strong majority (80%) of fishers in England agree that the conservation and restoration of the marine environment is important for their job security.
Clive Mills, Sussex fisherman, said:
“I used to have my own trawler, and I’d be out there all day and night. I could see with my own eyes the damage being done. It’s not just what you land, it’s what you kill. It’s the destruction that bottom trawling does, on a massive scale. If we did it on the land, you would literally stop it overnight. People would be up in arms and there would be uproar. But because we can’t see it, we let it happen. We’ve just got to look at what we’re doing now. We need to change what we’re doing. We need to look it in the eye and start fishing for the future.”
To mark the launch, Oceana UK commissioned a large-scale projection on the white chalk cliffs of Botany Bay, which looks out over an MPA that is home to the amber-listed little tern. Footage of bottom trawling transformed the cliffs into a powerful reminder of the ongoing destruction.
[1] In this report and release bottom trawling is defined as fishing with bottom-towed gear, including bottom and semi-pelagic trawls, dredges and seines, which are towed on or very close to the seabed and for which any part of the gear is designed and rigged to operate on, and be in contact with, the seabed.
[2] For this analysis, Oceana analysed 2025 vessel activity in a selection of cetacean and seabird MPAs using Automatic Identification System (AIS) data from Global Fishing Watch (GFW), an independent non-profit founded by Oceana in partnership with Google and SkyTruth. Oceana isolated vessel tracks within MPAs that GFW algorithms identified as apparent fishing, before narrowing the dataset to vessels registered as carrying bottom-towed gear (including demersal trawls, dredges, and bottom-contacting seines) as at least one of their gear types. Further details on the methodology are included in the report.
GFW uses data about a vessel’s identity, type, location, speed, direction and more that is broadcast using the AIS and collected via satellites and terrestrial receivers. GFW analyses AIS data collected from vessels that its research has identified as known or possible commercial fishing vessels and applies a fishing presence algorithm to determine “apparent fishing activity” based on changes in vessel speed and direction. The algorithm classifies each AIS broadcast data point for these vessels as either apparently fishing or not fishing and shows the former on the GFW fishing activity heat map. AIS data as broadcast may vary in completeness, accuracy and quality. Also, data collection by satellite or terrestrial receivers may introduce errors through missing or inaccurate data.
GFW’s fishing presence algorithm is a best effort to mathematically identify “apparent fishing activity.” As a result, it is possible that some fishing activity is not identified as such by GFW; conversely, GFW may show apparent fishing activity where fishing is not actually taking place. For these reasons, GFW qualifies designations of vessel fishing activity, including synonyms of the term “fishing activity,” such as “fishing” or “fishing effort,” as “apparent,” rather than certain.
Any/all GFW information about “apparent fishing activity” should be considered an estimate and must be relied upon solely at your own risk. GFW is taking steps to make sure fishing activity designations are as accurate as possible. GFW fishing presence algorithms are developed and tested using actual fishing event data collected by observers, combined with expert analysis of vessel movement data resulting in the manual classification of thousands of known fishing events. GFW also collaborates extensively with academic researchers through its research program to share fishing activity classification data and automated classification techniques.
