Checklist and status of non-native marine and estuarine species in Southern Brazil

To prevent the introduction, control or eradicate non-native species (NNS), an essential first step is to compile and maintain regional up-to-date lists of NNS. With the aim of contributing to a review of the marine biodiversity of southern Brazil (Paraná, Santa Catarina and Rio Grande do Sul states) for marine spatial planning, we compiled regional records of all marine NNS from the literature up to September 2024, created an updated checklist with the status of each species and analysed spatial, temporal, ecological and habitat use patterns by taxonomic group. For southern Brazil, we found 1,678 records of 104 NNS in marine or estuarine habitats, of which 43 species (41%) were considered invasive. These fell into 23 classes, with Malacostraca, Teleostei, Ascidiacea, Polychaeta and Bivalvia most speciose. Zoobenthic species were most frequent (70%) then nekton (15%). The ragworm Alitta succinea, the pacific oyster Magallana gigas, the muzzled blenny Omobranchus sewalli, and the copepod Temora turbinata had the highest number of records (> 100). Species detection rate increased from 1997 and yearly records increased from 2004 to the present (~3 additional species and mean of 64 records per year). Species and records were not evenly distributed. Although Santa Catarina (SC) had more NNS (n=67) than Paraná (PR, n=60) or Rio Grande do Sul (RS n=32), PR was relatively much more invaded (PR=6.1 species.10km-1 coastline vs. SC=1.3 and RS=0.5). Significantly less species and records are found south of 28°S (south of Santa Catarina Island), and records are concentrated in Paranaguá Bay, Babitonga Bay, Florianópolis/Santa Catarina Island and Rio Grande, where there are ports, shipping and major coastal urban infrastructure (about one third of records were in artificial habitats, especially marine farms). Estuaries and rocky reefs are the most invaded ecosystems. We predict that the region will have approximately 200 NNS in 30 years.