Tracking bottom-fishing activities in protected vulnerable marine ecosystem areas and below 800-m depth in European Union waters.

Numerous studies have highlighted bottom-contact fishing gears as the primary threat to vulnerable marine ecosystems (VMEs). In November 2022, the European Commission closed 87 VME protection polygons to bottom fishing in European waters. Using public automatic identification system (AIS) data, we found an 81% decrease in bottom-contact fishing effort within these areas in the year following the closures. However, approximately 3500 hours of bottom-contact fishing persisted within the closures. We also quantified up to 17,600 hours of bottom-contact fishing in unprotected areas where VMEs are known or likely to occur. Last, our analysis revealed ongoing bottom trawling below 800 meters in European waters totaling 19,200 hours over 2 years. These findings underscore the urgent need for states to enhance surveillance and monitoring of their fleets to ensure effective fisheries management.