Morphometric dataset of the golden mussel Limnoperna fortunei collected in the Tocantins River, Pará State (Eastern Amazon)

The invasive bivalve mollusk Limnoperna fortunei (Dunker 1857), popularly known as the “golden mussel”, was recently recorded in the Amazon region. Native to Southeast Asia, L. fortunei has been present in Brazilian waters since the 1990s and, due to its biological and ecological characteristics, found an environment favorable to its proliferation in the country. Several records of the species are documented in the scientific literature, as well as the numerous environmental and economic impacts caused by this invader. Here, we present the first qualitative and quantitative data on the bioinvasion of L. fortunei in the Brazilian Amazon region. Sampling was carried out in October 2024 on Pedral do Lourenço, which is a rock formation located in the Tocantins River between the municipalities of Marabá and Tucuruí (State of Pará). An average length of 12.22±4.19 mm in total length was found, ranging from 1.92 mm to a maximum of 22.10 mm, with an average population density of mussels found of 11,940 ind.m2, with records of up to 15,849 ind.m2. This is the first study containing preliminary data on the population structure of L. fortunei for the Amazon region. The results indicate a recent settlement in the Tocantins River, with evidence of at least one reproductive cycle already completed. Furthermore, due to a recent record in the state of Tocantins and the possibility that its introduction route from the Tocantins River was through the trade of juvenile fish for aquaculture, we indicate that the introduction probably occurred through the water bodies that connect this state with the state of Pará. Monitoring a wide area of the Tocantins River and its tributaries will enable a better diagnosis of the invasion, enabling the application of mitigating measures.