First record of the invasive red lionfish (Pterois volitans) in the Parcel de Manuel Luis Marine State Park, Brazilian Equatorial Margin

The red lionfish (Pterois volitans), native to the Indo-Pacific, is recognized as one of the most harmful invasive species in the marine ecosystems of the Western Atlantic. Since its accidental introduction, the species has rapidly expanded across the Caribbean, Gulf of Mexico, and Brazilian coast, reaching marine protected areas with high ecological value. This study documents the first confirmed occurrence of P. volitans in the reef environment of the Parcel de Manuel Luis Marine State Park, located on the Brazilian Equatorial Margin. The record was based on underwater footage collected during a scientific expedition in June 2025. Two individuals were observed near the wreck of the ship Ana Cristina at a depth of five meters. The specimens exhibited typical morphological features and behavioral patterns associated with foraging and habitat exploration. Physicochemical variables measured at the site confirmed stable tropical marine conditions, including high salinity and temperature, compatible with the ecological tolerance of the species. Additional measurements at eight surrounding stations revealed minimal stratification, reinforcing the environmental suitability for the species. Statistical analysis detected no significant differences in salinity or dissolved oxygen between surface and bottom waters, and a slight variation in temperature. The presence of P. volitans in a conservation unit raises concern about its potential expansion into other reef and coastal environments. Given its high reproductive capacity, absence of natural predators, and ecological plasticity, the species poses a serious threat to native biodiversity and trophic dynamics. The results highlight the urgency of establishing systematic monitoring programs and early-response strategies for invasive species in Brazilian reef systems.