A study on seabed recovery after bottom trawling bans in Scotland shows that marine life can bounce back strongly when given adequate protection.
Bottom trawling is a commercial fishing method that drags heavy nets and weighted gear across the ocean floor. It is highly effective at catching fish, but it also crushes habitats, displaces sediment, and kills the small creatures that hold marine food chains together. The practice has shaped European seabeds for centuries, dating back at least to the 14th century, which is why seabed recovery after bottom trawling bans is now drawing so much scientific attention.
Scientists from the Convex Seascape Survey, a global research effort involving the University of Exeter, the Blue Marine Foundation, and Convex Group, studied Scotland’s South Arran Marine Protected Area, or MPA. The site has been shielded from bottom trawling and dredging for nearly a decade. The results show that protected seabeds support roughly twice as many species and up to three times the abundance of marine life compared with nearby areas still open to trawling.
More than 1,500 species were recorded in the protected zone, including worms, shellfish, and other small invertebrates that form the foundation of the marine food chain. Think of these creatures as the ocean’s engine room. Without them, larger species struggle to find food and reproduce.
The data on the seabed recovery after bottom trawling bans also overturns a long-held assumption about muddy ocean floors. Scientists and fishers once considered these habitats ecologically unimportant. The South Arran data tells a different story. Muddy seabeds, often dismissed as barren, are proving to harbor rich, recoverable communities when left undisturbed.
Researchers documented diverse marine life, including spoon worms, bobbit worms, and tower snails, creatures that may appear unremarkable but serve as critical gardeners of the seabed. These organisms perform essential ecosystem functions, collectively turning over sediments equivalent to eight Mount Everests’ worth of material every minute across global continental shelves. That sediment activity supports both carbon storage and the gradual rebuilding of ancient seafloor ecosystems destroyed over centuries of trawling.
The results from Scotland are not unique. Evidence from across the UK reinforces the same message. Along the Sussex coast, five years after a trawling ban removed destructive gear from more than 300 km² of seabed, mussel beds stretching over a kilometer have begun to re-establish themselves, and populations of commercially important fish such as black sea bream are showing signs of increase. Before that ban, an estimated 96% of the region’s kelp had disappeared, driven by a combination of trawling, marine heatwaves, storm disturbance, and sedimentation.
At Lamlash Bay, also in Scotland, a protected zone established in 2008 now supports roughly three times the seabed life recorded before trawling was banned there. The protected area held 10 times more juvenile cod than the surrounding open-water fishing grounds. Juvenile cod are critical to future fish populations. More juveniles today means more adult fish available for sustainable harvests tomorrow.
Evidence from multiple UK locations, such as in Lamlash Bay, shows that seabed recovery after bottom trawling bans delivers gains not just for biodiversity, but also for carbon storage and the long-term health of commercial fisheries. Photo by Janet Newman-Carty on Pexels.
The findings on seabed recovery after bottom trawling bans carry important implications beyond biodiversity. Healthy seabeds store carbon, a process called carbon sequestration. Researchers found early signs that protected sediments strengthen the link between soil health and carbon retention, suggesting that seabeds can eventually become reliable carbon stores. However, this process is fragile and can be disrupted if trawling resumes. Protecting the seabed is, in part, a climate strategy.
Despite the evidence, the scale of protection across Europe remains far too small. While roughly 13.7% of European Union marine areas carry protected area status, just 0.2% of Europe’s seabed is currently shielded from destructive bottom-towed fishing. That gap between designation and actual protection is where the work needs to happen.
Lead researcher Dr. Ben Harris of the University of Exeter noted that seabed communities recover more slowly than fish populations in protected areas. That means protection needs to be long-lasting and consistently enforced to deliver its full ecological benefits. Short protection windows are not enough. Professor Callum Roberts, also of the University of Exeter, put it plainly: the evidence that seabed recovery after bottom trawling bans works is clear, and what is missing now is the urgency to act on it.
The science is clear, the examples are growing, and the tools for action already exist. Expanding bottom trawling bans and properly enforcing existing MPAs represent one of the most direct investments available for ocean health. Every protected square kilometer is an opportunity for exactly the kind of seabed recovery after bottom trawling bans that Scotland has demonstrated. What happens next depends on the decisions policymakers and fishing communities make today.
