The European Commission closed 87 deep-sea fishing areas in November 2022, and a new study has found that the decision resulted in an 81-percent reduction in bottom-contact fishing effort in vulnerable ecosystems over the following year.
The study, published in “Science Advances,” used Global Fishing Watch data to determine pre- and post-closure fishing effort in vulnerable marine ecosystems (VMEs) subject to the closures, finding that pre-closure fishing effort totaled an estimated 19,000 hours, which reduced to 3,500 fishing hours post-closure.
“This is extremely promising and shows that closures are effective. However, if governments do not monitor and enforce the closures, they will not work,” Natasha Mallet, a co-author of the study, said. “In a battle to see who can grab the most as quickly as possible with no legal repercussions, industrial fisheries will always win, and fishermen who have abided by the closures will lose out.”
The closures followed goals laid out in the E.U.’s Deep-Sea Access Regulation, enacted in 2017, which banned bottom trawling for deep-sea species below 800 meters and required the protection of known VMEs between 400 meters and 800 meters.
“While some argue that deep-sea habitats are ‘out of sight, out of mind,’ their degradation can have cascading effects on ocean health and human well-being. Healthy oceans regulate climate, ensure food security, and support economic stability. Marine ecosystems are deeply interconnected, and damage to deep-sea environments can ripple across the entire ocean,” Lissette Victorero, the study’s lead author, said.
Only 10 percent of ocean areas between 400 meters and 800 meters are effectively protected, and below 800 meters, no meaningful protections exist, according to Victorero.
“Given the potential for irreversible harm … the precautionary principle dictates that conserving these habitats now is essential to preventing future ecological crises. Protecting these ecosystems ensures long-term ocean health, which is inextricably linked to human health and survival,” Victorero said.
Spain recorded the highest fishing effort within protected VME areas at 1,769 hours during the period studied, followed by the French fleet with 620 hours. VME Polygon 13 on the West Iberian Shelf saw over 500 hours of fishing, primarily by the Portuguese fleet. In the Celtic Seas ecoregion, vessels from France, the U.K., and Ireland continued fishing.
“If [VMEs] are destroyed by fishing efforts, there will be no more fish, and the areas will lose all significance. These closures are an effort to preserve deep-sea species for future generations, not a punishment,” Mallet said.
Though the closures represented a win for deep-sea ecosystem protection, Victorero clarified that they only concerned a “tiny fraction” of VMEs and E.U. waters overall.
Illustrating the point, in addition to the 3,500 hours of fishing within protected areas during the period, around 176,000 hours of bottom-contact fishing occurred in unprotected areas where VMEs are known or likely to exist, along with 19,200 hours of bottom trawling below 800 meters in E.U. waters.
“The closures are small and fragmented. It’s in the interest of the industry to ensure we have sustainable fisheries and ecosystem recovery in our waters,” Victorero said. “While some outliers remain, the majority of the industry is complying. The Deep-Sea Access Regulation is not optional; it’s a legal requirement E.U. countries must enforce. Enhanced surveillance and monitoring will be key to ensuring full compliance and closing gaps in protection.”
The fishing industries of certain countries like Spain have fought the closures, but the European Commission’s Scientific, Technical, and Economic Committee for Fisheries (STECF) found that the closures affected just 10 percent of the sector fishing between 400 meters and 800 meters with bottom-contact gear.
“The fishing industry – which is distinct from fishermen – may oppose the closures, as evidenced by Spain challenging the E.U.’s measures in court, with a verdict expected soon from the Court of Justice of the European Union. However, it’s crucial to recognize that the proportion of E.U. waters genuinely protected remains minimal, and there is a significant imbalance between extraction and conservation in our waters,” Victorero said.
The partial success of these closures has prompted the Deep Sea Conservation Coalition (DSCC), an Amsterdam, Netherlands-based alliance aiming to promote conservancy on the world’s high seas, to urge the E.U. to continue implementing these regulations, including a 2025 priority to adopt new closures that protect all seamounts and other VMEs in E.U. waters.
The DSCC has also emphasized the need for improved fleet surveillance, recommending the use of AIS data, which provides real-time fleet position updates every six to 12 seconds, instead of the current system that updates every two hours.
“The ocean is not an endless source of food; the last few decades have proved it. If fishing in Europe is to continue at scale, it needs to transition away from industrialized large-scale overexploitation to a more sustainable model. That starts by ensuring that fishing regulations are applied universally,” Mallet said.
The study said that its findings represent a conservative estimate, as a large portion of the global industrial fishing fleet is absent from public monitoring data. Also, foreign ships are not required to report their gear, unlike the E.U. fleet and, therefore, are excluded from the study.
Other solutions to harm arising from bottom trawling besides instituting closures may come from new technology.
A startup in Nova Scotia, Canada, for example, is developing a bottom-trawling unit that hovers above the seafloor, avoiding contact with VMEs and reducing negative impacts on critical seabed environments.
