Invasive lionfish spread through southwestern atlantic marine protected areas

Invasive lionfish are recognized as a major management concern in Marine Protected Areas (MPAs) because of their high density and adverse effects on native biodiversity, fisheries, and food web processes. Despite these pressing concerns, there is a lack of research focused on the current and future invasion of lionfish in Southwestern Atlantic MPAs. To address this knowledge gap and support global marine conservation efforts, our study systematically assessed the extent and types of MPAs invaded by lionfish (Pterois volitans) in the SW Atlantic. Additionally, we used Species Distribution Models (Maximum Entropy modeling) to predict potential future distributions of this invasive species. Our findings revealed that lionfish have successfully invaded at least 18 Marine Protected Areas (MPAs) between 2020 and 2024, across a 4000 km stretch of the SW Atlantic. These include twelve protected areas with sustainable use, three marine parks, one biological reserve, and two reserves dedicated to protecting artisanal fisheries. Based on the confirmed invasions, the majority of the affected MPAs (78 %) were multiple-use, with 22 % designated as no-take areas. The growth of lionfish populations is expected to continue in part due to the absence of regular culling efforts in most (88 %) of these MPAs. The potential distribution model predicts that lionfish currently occur in 33 % of Brazilian MPAs and will expand its range to an additional 25 MPAs within the next 10 years, potentially reaching 60 % of the total Brazilian MPAs. The results also showed that the benthic salinity range and sea body temperature were the most critical factors in predicting lionfish distribution across SW Atlantic MPAs in both current and projected scenarios. This rapid spread underscores the urgent need for coordinated management strategies to mitigate the threat posed by lionfish throughout the Atlantic Ocean basin.