The lionfish Pterois volitans (Linnaeus, 1758) is considered the most well-established fish species in non-native regions around the world, causing severe environmental damage and risks for the food chain. In Brazil, the lionfish was reported for the first time in 2014 in the State of Rio de Janeiro, and currently, the P. volitans was observed in more seven States, being its high level of occurrence in the Northern region, which contains an immense biodiversity that has not been totally cataloged yet. Based on that, this study aims to ratify the occupation and permanent residence of the lionfish in the Great Amazon Reef System (GARS), which is an alert for the urgent need for developing control strategies for this invasive species in Brazil. The new specimens were collected in the State of Amapá, between 2021 and 2022, during commercial lobster fishing, using the method of “Caçoeira”, covering between 70 and 100 meters of depth, while for the snapper was collected with the manzuá, between 78 and 102 meters of depth. In the laboratory, the individuals were measured in total length (TL) and total weight (TW). We analyzed 21 specimens of P. volitans from the GARS, the TL ranged from 21,5 to 35,6 cm with an average of 29,43 cm, while the TW ranged from 150,0 to 733,0 g, with an average of 413,8 g. These adult specimens reinforce the stabilization of the lionfish, which have probably completed reproductive cycles in the region, requiring an urgent action by environmental agencies to control the invasion of the lionfish in Brazil, becoming a future environmental impact on native biodiversity.
