A synthesis concerning fishes from Upper Paraná River basin is presented, based on data from fish-collections, literature, and new field samples. Three hundred and ten species, pertaining to 11 orders and 38 families, are referred to the drainage, elevating anterior estimates. Concerning total species, 236 (76.1%) are autochthonous, 67 (21.6%) are allochthonous, and seven (2.3%) are exotic. Principal causes of occurrence of non-native species are: a) dispersal from the Lower Paraná, after the construction of Itaipu dam, and b) escapes from aquaculture farms. Most species (65%) are small-sized, having less than 21 cm of length, and the great majority occurs only in headwaters and small streams. One of the best known and most studied in Brazil, Upper Paraná ichthyofauna richness is far from reaching actual numbers, considering the exponential elevation of species presented herein. Indeed, in the last years various new species have been described and around 50 other species, already recognized as new, are now under description. The improvement on the knowledge about Upper Paraná ichthyofauna is proportional to the number of researchers involved with studies in the area and, unequivocally, reflects recent initiatives stimulating and incrementing taxonomic research, and also improving access to fish collections and to poor or never-sampled areas. However, if we are going to maintain the number of species descriptions per year of last decade, the 50 new species already recognized, will be described only in the next ten years, a period too long. In consequence it is very important that scientific community and grant agencies find and offer initiatives in order to elevate the number of new taxa descriptions per year.Keywords: fishes, freshwater, southeasten Brazil, inventory, transposition. É apresentada uma síntese sobre os peixes do Alto Paraná, com base em dados de coleções, dados de literatura e novas coletas. Trezentas e dez espécies, de 11 ordens e 38 famílias, são referidas para a drenagem, aumentando significativamente números anteriores. Dentre as espécies da área, 236 (76,1%) são autóctones, 67 (21,6%) alóctones e sete (2,3%) exóticas. As principais causas de ocorrência de espécies não nativas (alóctones e exóticas) foram a dispersão a partir do baixo Paraná, após a construção do Reservatório de Itaipu e o escape de pisciculturas. A maior parte das espécies referidas (65%) tem porte pequeno, sendo menor que 21 cm de comprimento; dentre essas, a maioria

Abstract:The fish species living in the freshwaters of the São Paulo state (393) are distributed among four major river basins: upper Paraná, Paraíba do Sul, Ribeira de Iguape and a set of small coastal drainages flowing directly into the Atlantic Ocean. Since these river basins drain areas with distinct vegetation types, soils, etc., each one has a different species composition. In the Upper Paraná the large Rio Paraná and some of its large tributaries (Tietê, Paranapanema, and Grande) contain large species that support commercial fisheries, however, 70 to 80% of the ichthyofauna is composed by small species found in small streams, including those in headwaters where many are endemic. The inventory of the ichthyofauna greatly benefited from three research projects supported by the BIOTA/FAPESP program, but much work remains to be done to collect and describe new species from areas such as deep channels, headwaters and marginal and swampy áreas around ponds and man-made lakes and reservoirs. The ichthyofauna of the São Paulo State has suffered from deforestation, sewage, damming of rivers for construction of power plants, urbanization, etc., so that 66 species are currently considered threatened at various levels according to the criteria of the International Union for Conservation of Nature and Natural Resources (IUCN). Keywords: fresh water fishes, biodiversity of the State of São Paulo, BIOTA/FAPESP Program.

BackgroundFreshwaters are the most threatened ecosystems on earth. Although recent assessments provide data on global priority regions for freshwater conservation, local scale priorities remain unknown. Refining the scale of global biodiversity assessments (both at terrestrial and freshwater realms) and translating these into conservation priorities on the ground remains a major challenge to biodiversity science, and depends directly on species occurrence data of high taxonomic and geographic resolution. Brazil harbors the richest freshwater ichthyofauna in the world, but knowledge on endemic areas and conservation in Brazilian rivers is still scarce.Methodology/Principal FindingsUsing data on environmental threats and revised species distribution data we detect and delineate 540 small watershed areas harboring 819 restricted-range fishes in Brazil. Many of these areas are already highly threatened, as 159 (29%) watersheds have lost more than 70% of their original vegetation cover, and only 141 (26%) show significant overlap with formally protected areas or indigenous lands. We detected 220 (40%) critical watersheds overlapping hydroelectric dams or showing both poor formal protection and widespread habitat loss; these sites harbor 344 endemic fish species that may face extinction if no conservation action is in place in the near future.Conclusions/SignificanceWe provide the first analysis of site-scale conservation priorities in the richest freshwater ecosystems of the globe. Our results corroborate the hypothesis that freshwater biodiversity has been neglected in former conservation assessments. The study provides a simple and straightforward method for detecting freshwater priority areas based on endemism and threat, and represents a starting point for integrating freshwater and terrestrial conservation in representative and biogeographically consistent site-scale conservation strategies, that may be scaled-up following naturally linked drainage systems. Proper management (e. g. forestry code enforcement, landscape planning) and conservation (e. g. formal protection) of the 540 watersheds detected herein will be decisive in avoiding species extinction in the richest aquatic ecosystems on the planet.