Bertaco, Vinicius de AraújoAzevedo, Marco Aurélio2023Figure 2 in Non-native freshwater fish from drainages of Rio Grande do Sul State, Brazil10.5281/zenodo.7617850Figure 2. Total number of records of exotic species per year cataloged in scientific collections between 1965 and 2020. from the same locality; most black-bass records are from to Bertaco et al. (2016) from the 1990s to 2015 the num- Vacaria Municipality in 1978 and for tilapia are from ber of freshwater species described for the state of Rio Bento GonÇalves Municipality in 1977 (Fig. 1). The larg- Grande do Sul increased considerably when compared est number of records presented by the common carp to previous decades, mainly due to the increase in huis possibly due to its being the first exotic species intro- man and financial resources destined for this purpose. duced in the country in 1882 (Nomura, 1977), and, con- Regarding the total number of records of exotic spesequently, one of the most cultivated species in fish cies per hydrographic basin, the highest number ocfarming (Baldisserotto, 2009), in together with its variet- curred in the basins of the Laguna dos Patos (89; 70.6%), ies, such as the mirror carp. the upper Río Uruguay (24; 19%), the lower Río Uruguay Considering the total number of records of exot- (7; 5.5%) and the Rio Tramandaí (4; 3.2%) (Fig. 3). Some ic species recorded per year in scientific collections be- black bass records were not accounted for, as it was not tween 1965 and 2020 (Fig. 2), the years with the high- possible to locate the watershed due to incomplete est number of records were 1978 (24; corresponding to source data, as the registered municipalities cover more 17% of the total), 2008 (16; 11.3%), 1977 and 1997 (both than one watershed. The scientific collections with the with 12; 8.5%). Many of these records only make refer- highest number of records of exotic species were MCP ence to the municipality where the material came from, (87; 61.3%), UFRGS (21; 14.8%) and MCN (18; 12.7%), not presenting more precise information about the lo- among the nine collections analyzed and with informacation of the collection site. The high number of records tion on exotic species in the state (Fig. 4). found in 2008 and 1997 is directly related to the increase in ichthyofauna studies carried out in dams, hydroelectric plants and small hydroelectric plants, as these sur- Allochthonous species veys and monitoring are required by the responsible environmental agencies as a means of mitigating the im- The eight allochthonous species are distribpacts caused by the implementation of these projects. uted in three orders, eight genera, and six fami- As well as the number of records in the collection, the lies (Table 2). The piava Megaleporinus macrocephnumber of articles that record the occurrence of non-na- alus (Anostomidae), pacu Piaractus mesopotamicus tive species (including exotic and allochthonous species) (Serrasalmidae, Fig. 5), peixe-cachorro Acestrorhynchus of freshwater fish in the Neotropics has increased signifi- pantaneiro (Acestrorhynchidae), jejú Hoplerythrinus unicantly over the years, especially in the last two decades taeniatus, traírão Hoplias lacerdae (Erythrinidae), porru- (Gubiani et al., 2018). Knowledge of the fish fauna of a do Trachelyopterus lucenai (Auchenipteridae), and corviregion or watershed is closely related to the collection na-de-rio Pachyurus bonariensis (Sciaenidae), have a nateffort (Bertaco et al., 2016), and the availability of finan- ural distribution encompassing the Río Uruguay basin. cial resources to develop research projects. According Over the last two decades (except for T. lucenai recorded