Effectiveness of marine protected areas in reducing industrial fishing pressure in Brazil

Marine Protected Areas (MPAs) are a key tool for protecting biodiversity and reducing anthropogenic threats, yet their conservation effectiveness remains variable. We evaluated 21 Brazilian MPAs to identify their capacity to reduce apparent industrial fishing pressure, using data (2017-2024) based on the Vessel Monitoring System (VMS) from Global Fishing Watch inside and around MPAs boundaries. Analyses incorporated three non-overlapping distance bands extending from 0-5 km, 5-10 km, and 10-50 km beyond MPA boundaries to capture spatial variation in fishing patterns. Although industrial fishing decreased within 85% of MPAs, only 38% exhibited statistically significant differences between apparent fishing inside versus outside their boundaries. Community-based MPAs were most effective, followed by no-take (i.e., fully-protected) MPAs, whereas only half of multiple-use MPAs were effective in reducing fishing. Patterns of apparent fishing pressure reduction varied across distance bands, underscoring the importance of defining appropriate monitoring boundaries for performance evaluation. Analyses of fishing showed that pots-and-traps and drifting longlines exhibited the greatest reductions within MPAs, while purse seines and, notably, trawling had the smallest reductions. While no-take and community-based MPAs were effective even under high fishing pressure, multiple-use MPAs showed the opposite pattern. These findings reinforce the role of MPAs to reduce apparent fishing pressure, a key mechanism through which MPAs are expected to contribute to biodiversity conservation, and underscore the need for gear-specific regulations, robust enforcement, and adaptive management to enhance MPA effectiveness in Brazil.