Bottom trawling costs society up to €16 billion annually, according to a study published by National Geographic Pristine Seas.
Billed as the first study to measure the full economic value of bottom trawling in Europe’s waters, it came to its conclusions by pooling data from more than 4,900 European-flagged bottom trawlers.
It calculates that these vessels together spend more than 5.5 million hours fishing on average each year in the waters of the EU, Britain, Norway and Iceland, and says that atmospheric carbon dioxide (CO2) emissions from disturbed seafloor sediments are a major contributor to these costs.
The study concludes that the net costs of bottom trawling to society are 90 times greater than the €180 million in profits raked in by the fishing industry each year.
“Our study makes it clear that bottom trawling in European waters is not just an environmental disaster, it’s an economic failure,” said Professor Enric Sala, National Geographic Explorer in Residence and one of the authors of the study.
Entitled “The value of bottom trawling in Europe” , and published in the journal Ocean & Coastal Management, the study comes as experts and advocates increase pressure on government and industry leaders across Europe to ban bottom trawling, especially in marine protected areas (MPAs) set aside for safeguarding marine ecosystems.
It says that research finds that, globally, the churning of seafloor sediment by bottom trawling is responsible for injecting up to 370 million metric tons of carbon dioxide into the atmosphere every year.
The new study suggests that nearly a third of this (112 million metric tons) is coming from European-flagged trawlers.
“Not all big is bad, nor all small beautiful, but where there is clear evidence that the economic and/or environmental costs of larger-scale mobile fishing gears outweigh any societal benefit from harvesting the resource, then it is right that alternatives are found and such operations are phased out,” says Jerry Percy, senior advisor to the Low Impact Fishers of Europe (LIFE).
“Small-scale fishers in Europe, on the other hand, prove every single day that we can feed communities by catching fish sustainably — without disturbing spawning grounds or kicking up carbon.”
This study calculates that 23% of the continent’s bottom trawling effort (in terms of hours spent fishing) takes place in MPAs across the area studied.
Authors found that the figures vary by country, with more than a quarter of the annual trawling effort in the EEZs of Belgium, Bulgaria, France, Germany, Netherlands, Romania and Spain occurring in MPAs.
Bottom trawling’s impacts on marine life in the region’s 6,000 MPAs encompassing 900,000 square km (347,492 square miles) are well documented, it says.
Research shows that populations of sharks, rays and skates were more plentiful outside the boundaries of MPAs than within the MPAs. Bottom trawling in MPAs undercuts the role these marine reserves play in replenishing fish populations outside their borders, called spillover, it says.
Recent research catalogued more than 3,000 fish species caught in bottom trawls globally,including endangered animals. The impact to ecosystems of so many species being removed from the ocean is not yet fully understood but it is likely to be highly negative.
Researchers analysed bottom trawling efforts in European waters between 2016 and 2021, then compared its benefits (fishing revenue, protein supply and jobs) to its costs (fuel and labour, discarded fish, subsidies and carbon emissions), finding that the costs of bottom trawling far outweigh its benefits.
While net benefits to the fishing industry alone are positive (estimated at
€180 million annually), the net benefit to society is negative on the order of €2.25 billion to
€16.15 billion (the range reflects the different valuations of the social cost of a ton of CO2
emitted into the air), it says.
The largest single cost of trawling European waters is the social cost of CO2 emissions — an estimate of the future economic damage caused by climate change impacts, including sea level rise and declining labour productivity and human health.
The study estimates two CO2 costs associated with bottom trawling: emissions from burning fuel (gasoline or diesel) and emissions from disturbance to carbon on the sea floor.
“Bottom trawl gear scrapes up the seafloor, releasing carbon that’s been stored in the ocean seabed for centuries,” said Kat Millage, marine researcher for National Geographic Pristine Seas and lead author on the study.
“It is clear that the magnitude of emissions from trawling are substantial. Even when we use a very conservative estimate of the social cost per metric ton of emitted CO2, society is left bearing a heavy economic burden.”
The new research found a significant cost to European taxpayers through
subsidies. European governments spend an estimated €1.17 billion on bottom trawling to offset the price of fuel and other costs in the name of food and job security.
However,without these subsidies, bottom trawling activity would be unprofitable for some nations,including Belgium, Spain, Great Britain, Portugal and Romania.
It also says that the costs of food waste stemming from bottom trawling are massive. Up to 75% of the marine life caught up in bottom trawling nets die and are discarded back into the ocean, valued at €220 million every year. Discarded animals include unwanted juvenile fish, low-value fish, bottom-dwelling sharks like catsharks and dogfish, rays and skates — as well as sponges, sea squirts, sea stars, corals and sea pens.
It says that bottom trawling vessels require massive amounts of fuel to drag heavy nets across the seafloor. Norway and Iceland spend the most on fuel. At least half the Dutchfleet stayed in port at the end of March 2026 because of soaring diesel costs amid the Iran crisis, demonstrating the tenuous economic viability of bottom trawling.
Fisheries’ benefits are often limited to the revenue generated by the fishing industry. For this study, researchers also quantified some of the social benefits:
- Protein: Ultimately, bottom trawling only provides 2% of the animal protein consumed in all of Europe. This provides an estimated social value of €2.46 billion per year.
- Jobs: Bottom trawlers directly employ less than 20,000 people in Europe, providing a social benefit of approximately €1.78 billion per year. For comparison, small-scale fisheries in Europe generate approximately three times more jobs than industrial bottomtrawlers.
“The results of our study suggest that cost-benefit analyses used in marine policy evaluations need to move beyond narrow market metrics and embrace the full scope of economic theory on valuation if they are to capture the full consequences of destructive fishing gears such as
bottom trawling,” says Rashid Sumaila, Ocean and Fisheries Economist at the University of British Columbia and co-author of the report.
The researchers could not quantify the economic cost of the ecological damage inflicted on the ocean by bottom trawling , nor the cost to other fisheries (arising from bycatch).
However, research shows remarkable recovery of marine life in areas after banning bottom trawling, including a 95% increase in reef species and a 400% increase in juvenile lobsters.
In the study, the researchers simulated how changes to the bottom trawling effort could impact the balance between costs and benefits. They concluded that reducing bottom trawling activity across Europe by just over half could increase overall benefits.
Such a reduction would help restore Europe’s overfished seas, avoid large carbon dioxide emissions, and maximize food production by making European fishing more sustainable. The subsidies currently used to support bottom trawling could be directed towards the industry’s transition to less damaging practices.
“Ending bottom trawling in Europe’s marine protected areas is essential for saving billions in public costs, " said Professor Sala.
“This move will save taxpayers money, protect marine life, boost the fishing industry and help us reduce global warming. If European governments were to direct just a fraction of the current fisheries’ subsidies to help the industry transition away from bottom trawling, society and marine life would win out, "he said.
European leaders have already taken steps to ban bottom trawling. In April 2024, Greek Prime Minister Kyriakos Mitsotakis announced his commitment to ban bottom trawling in Greek MPAs by 2030; Sweden followed two months later.
The European Commission’s action plan calls for “gradually phasing out bottom fishing in all MPAs by 2030, in view of their key role in restoration of marine biodiversity and the importance of the seabed for healthy marine ecosystems and climate change mitigation.”
