19Understanding the pathways and impacts of non-native species is important for helping 20 prevent new introductions and invasions. This is frequently challenging in regions 21 where human activities continue to promote new introductions, such as in Brazil, where 22 aquaculture and sport fishing are mainly dependent on non-native fishes. Here, the non-23 native fish diversity of the Paranapanema River basin of the Upper Paraná River 24 Ecoregion, Brazil was quantified fully for the first time. This river has been subject to 25 considerable habitat alteration through hydroelectric dam construction and concomitant 26 development of aquaculture and sport fishing. Through compilation of a non-native fish 27 inventory by literature review, with complementary records from recent field studies, 28

The Paranapanema River is an important, extensively explored tributary of the Upper Paraná River basin. The fish fauna of the Paranapanema River has been investigated since the 1990s; however, no study has characterized the richness of fish species throughout the basin, including the main channel of the river, marginal lagoons, its tributaries, and sub-tributaries. Thus, we performed a review with 90 independent studies conducted at the upper, middle, and lower sections of the basin. We recorded 225 species, of which 165 were native, and 60 were non-native. We found that 77% of the species within the basin are composed by Siluriformes and Characiformes. Cichliformes had a significant number of non-native species established in impoundment sections of the basin. Incidence-Based Estimators (Bootstrap and Chao 2) demonstrated that the richness of native species is still underestimated. Some native (e.g., Hypostomus ancistroides) and non-native species (e.g., Plagioscion squamosissimus) are widely distributed in the basin, while others had a more restricted distribution. Among the registered species, the family Bryconidae had the highest number of representatives with threatened conservation status. In addition, we observed that the Capivara Reservoir and its tributaries were the most sampled regions, with the majority of studies performed in the Lower Paranapanema basin. The species richness recorded in large tributaries, such as Tibagi, Cinzas, Congonhas, and Pirapó rivers is critical for maintaining the fish fauna in the Paranapanema River. Our contribution may be used to support management actions and conservation strategies, as well as to indicate regions in the basin that need to be better inventoried.

O aquarismo é um hobby praticado mundialmente com aumento de popularidade no Brasil nas últimas décadas. A soltura de peixes ornamentais em ambientes naturais é equivocada, sendo considerada introdução de espécies e crime ambiental. Dessa maneira, objetivou-se verificar a existência de registros de solturas disponíveis na web, na mídia social Youtube™ no Brasil. A busca por vídeos com situações de soltura ou descarte foi realizada entre julho e dezembro do ano de 2018, totalizando-se 616 horas de busca. Como resultado, obteve-se 48 registros de solturas, sendo as mais incidentes as regiões do Sudeste, Nordeste e Sul. São Paulo, Minas Gerais, Espírito Santo e Rio de Janeiro foram os Estados com maior número de registros. Registrou-se 33 táxons de peixes (18 gêneros e 15 espécies) e dois híbridos, sendo muitas delas espécies invasoras. A maioria dos praticantes não tem conhecimento sobre a ilegalidade do ato ou a possibilidade de impacto ambiental. O perigo das solturas ornamentais quanto à oportunidade de invasão biológica, a pressão de propágulo empregada e os conceitos equivocados sobre ecologia abordados nos vídeos são discutidos. Sugere-se a conscientização dos aquaristas e maior controle sobre o hobby, sendo as redes e mídias sociais uma nova ferramenta para os órgãos fiscalizadores detectarem distúrbios que possam prejudicar os ambientes naturais.

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