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.

Several studies of small watersheds of in the Upper Paraná River basin are currently available. However, the number and extent of its tributary streams still pose a challenge to enhancing current knowledge of their ichthyofauna. This study aimed to survey the fish fauna of three streams of the Lower Paranapanema River basin, state of Paraná, Brazil (Capim, Tenente and Centenário streams). The sampling included 3,167 specimens belonging to five orders, 17 families and 56 species. The streams presented differences in species richness (Centenário Stream: 41 species; Tenente Stream: 33 species; Capim Stream: 30 species). Two species occurred at all collection sites (Astyanax bockmanni and Hypostomus ancistroides). Nine non-native species were recorded, four of them found exclusively in the Centenário Stream.

The aim of this study is to report the presence of a three non-native hybrid long-whiskered catfishes (family Pimelodidae) in the Upper Paraná River basin, Brazil. Genetic analyses demonstrated that the three presumptive hybrids were a result of the crossbreeding of Pseudoplatystoma reticulatum (central Amazonas River basin and Lower Paraná River) and Leiarius marmoratus (Amazonas, Essequibo and Orinoco rivers), producing a hybrid commonly known in Brazil as cachandiá. The potential threat to biodiversity, due to possible genetic contamination, competition and predation of wild stocks, of such artificially produced hybrid fishes is discussed.

Length-weight relationships were estimated for six fish species occurring in direct tributaries of the Lower Paranapanema River Basin. Data is described for the first time for five species and new measurements are provided for one species in the FishBase database. Studies of fish diversity are critical for species management and conservation, especially in this basin, which has suffered from many anthropical impacts.

Animal-vehicle collisions are the main negative impact of roads on wildlife, where they cause population declines, shifts in community structure, and potential changes in species behavior. Here, we determined mammal roadkill rates and the hotspots with higher rates for medium- and large-bodied mammals on the Highway PR-445 in the state of Paraná, Brazil. We have also evaluated possible differences in the frequency of roadkills concerning species activity patterns and their feeding habits. In doing so, we monitored the PR-445 twice a week between the kilometers 1 and 76, from March 2018 to March 2019, totaling 7296 km after 96 trips. We have recorded 93 mammal roadkills belonging to 17 species, representing a rate of 0.013 individual/km/day. The Carnivora, Didelphimorphia, and Cingulata orders showed to be the most common representatives among the roadkills. Omnivores were more prone to get hit by vehicles than herbivores and carnivores. The type of mammal activity pattern was not determinant in explaining the differences in roadkill rates. Highways in Paraná are among the roads that register the highest number of vehicle collisions with vertebrates in the country. This issue, together with extensive habitat loss and fragmentation, increases the threats to the relictual fauna. Our results indicate that the regions with the highest incidence of mammal roadkills on PR-445 are those close to stretches over rivers and with remnants of native vegetation. Thus, we emphasize that more comprehensive measures (e.g., wildlife passages and speed reducers) are essential to mitigate the impact of roads on wildlife.