View the full report here.
● Half of UK fish is caught by bottom trawlers.
● One billion tonnes of CO2 is released from the seabed each year by bottom trawlers.
● If this figure were included in carbon footprint calculations, the actual footprint of some bottom trawled seafood could exceed those from all other protein sources, including lamb and beef.
BRISTOL, UK: Eating fish could be worse for the climate than previously thought, according to a new report investigating the contributions of the UK’s most prevalent fishing method to the climate crisis. The analysis, by researchers from the Transform Bottom Trawling Coalition and SWIDN Member Blue Ventures, revealed that some types of seafood caught by bottom trawling may have carbon footprints larger than all other foods.
It’s long been thought that seafood is a carbon-friendly source of food that provides protein and nutrients to billions of people at a far lower environmental cost than beef or lamb. This is because fishers don’t need to convert land for livestock, or rear animals.
But, the new report shows, not all seafood is good for the planet. It depends on what it is and how it is caught, and for species caught by bottom trawling, the carbon footprint could be greater than chicken, pork, lamb or beef.
Bottom trawling is a common way of catching fish that involves dragging heavy nets across the seabed. Around a quarter of the world’s seafood is caught this way, with vessels landing around 19 million tons each year, more than any other method. In some parts of the world, including the UK, it accounts for half of annual seafood landings.
The most comprehensive analysis of how bottom trawling accelerates the climate emergency, the new report combines established research on vessel emissions and carbon footprints with emerging findings on CO2 released from the seabed by trawl nets. Seafloor sediments and habitats are the world’s largest carbon sinks and disturbance by trawl nets is thought to release up to 1.5 billion tonnes of CO2 each year.
The report warns that even without the extra emissions caused by seabed disturbance, species like flatfish, shrimp and lobster that are caught by bottom trawling can have some of the highest carbon footprints of any protein source. This is largely because dragging a heavy net across the seafloor uses lots of fuel. Once the additional carbon released from the seafloor is factored into calculations, emissions from bottom trawling are likely to exceed those produced from beef and lamb.
“We know that the carbon footprint of bottom-trawl fisheries is about three times higher than non-trawl fisheries and that some species caught this way may create more than four times the emissions of the same species caught by other gears”, said lead author Steve Rocliffe. “But this isn’t the end of the story. For every tonne of seafood landed by bottom trawlers, about 50 tonnes of CO2 are released from the seabed by trawl nets. Add this in and it’s clear that some forms of bottom trawled seafood are about the worst foods we can eat for the planet.”
"In the fight against climate change, what we choose to eat can make a huge difference, and it’s clear that we need to eat more fish,” said Tom Collinson of the Transform Bottom Trawling Coalition. “But if we’re serious about honoring the Paris Climate Agreement and keeping global warming in check, it’s clear that we can’t keep bottom trawling in the way we do”.
The report sets out several interlinked steps to tackling bottom trawling’s outsized carbon footprint. These include continuing efforts to rebuild stocks through better management, as more fish in the sea means less fuel is needed to catch them.
Other recommendations call for prioritising lower-fuel fishing gears over bottom trawls, which the researchers say can reduce greenhouse gas emissions by up to 60%, and transitioning fleets to low-emission alternatives, particularly electric, hybrid, hydrogen and sail-assisted technologies.
The report also highlights an urgent need for greater restrictions on bottom trawling in marine protected areas, and for more inshore exclusion zones for small-scale fishers that prohibit bottom trawling and protect carbon rich habitats such as kelp forests and seagrass meadows.
“The sector can’t and shouldn’t do all this alone. It requires bold action by governments to end fossil fuel subsidies and redirect them to incentivise and support wholesale transformation,” Dr Rocliffe said. “With some of the most progressive climate fisheries policy in the world, the UK is in a unique position to ensure fish is firmly on the table during climate negotiations in Glasgow next week”
The report’s findings were unexpectedly echoed by the UK prime minister during a question-and-answer session with school children at Downing street earlier this week. In a surprise departure from government policy, Johnson characterised fishing practices that disturb seabed habitats as indiscriminate, disastrous and against the interests of sustainable fisheries, and pledged to move away from it.
About Blue Ventures
Thriving oceans, thriving fishers. Blue Ventures is a marine conservation organisation that puts people first. We support coastal fishers to rebuild fisheries, restore ocean life and build lasting pathways to prosperity.
Our work began two decades ago in Madagascar’s remote coastal communities and is growing globally. Across more than a dozen countries, we’re partnering with fishers and community based organisations to design, scale, strengthen and sustain fisheries management and conservation at the community level.
We bring partners together in networks to advocate for reform, and share tools and best practices to support fishing communities across the globe.
About The Transform Bottom Trawling Coalition
Working together to restore our ocean. The Transform Bottom Trawling Coalition brings together more than three dozen organisations from across the fisheries and conservation sectors. At its core, the Coalition is pro-small-scale fishing, pro-environment and dedicated to establishing and enhancing the rights of coastal communities.
The Coalition believes that addressing the most pervasive and severe form of destructive fishing – bottom trawling – is key to ensuring a future for the world’s coastal communities and ecosystems. It’s calling for bottom trawling to be urgently tackled by all coastal nations, to achieve a reduced global footprint by 2030.