Hydrological richness on extreme southern Bahia contrasts with the poorly known freshwater fish fauna. It is surprising the presence of several species still undescribed. The present study is the first contribution dealing with the fish fauna of the local river basins. We herein investigate fish fauna of Rio Peruípe basin, a remarkably freshwater drainage, with a wide estuary. Eleven localities, geo-referred, were evaluated in streams and rivulets along that freshwater drainage. The employment of methodology for collecting the environmental data and the fishes made possible the description of each locality sampled, as well as the documentation of the taxonomic composition of the fish fauna. Illustrations of the collecting localities and of individuals of some representative species, in live coloration, are provided. There were found 26 species belonging to 12 families in 6 orders. Within the species sampled Trichomycterus pradensis Sarmento-Soares et al. (2005) and Microglanis pataxo were recently described as new. About 48.7% of total amount of fishes caught belong to the order Siluriformes, 38.5% to Characiformes, 34.6% to Perciformes, 11.5% to Cyprinodontiformes, 7.7% to Gymnotiformes, 3.8% to Synbranchiformes, and 3.8% to Pleuronectiformes. The most frequent species in terms of constancy of occurrence were Geophagus brasiliensis (present in 82% of sampled localities), Hoplias malabaricus (64%), Astyanax cf. rivularis (55%), Poecilia vivipara (55%), Astyanax cf. lacustris (45%) and Hyphessobrycon bifasciatus (45%). Based on information about the fishes caught in each collecting locality there were estimated the richness, the diversity, the equitability and the dominance. The potential loss of microenvironments in some portions of rivers is pointed as a factor influencing on the occurrence and distribution of some species. The dominance of small sized fishes, not exceeding 150 mm CP, is associated to a high regional endemism.Keywords: ichthyofauna, riachos, coastal "tabuleiros", northeastern, Brazil. A riqueza hidrológica no Extremo Sul da Bahia é contrastante em relação à ainda pouco conhecida fauna de peixes. Impressiona a presença de diversas espécies ainda não descritas. O presente estudo é parte de uma série que pretende avaliar os sistemas hídricos do Extremo Sul da Bahia do ponto de vista da ictiofauna nas diversas bacias. Aqui são investigados os peixes da bacia do Rio Peruípe, um sistema ímpar de drenagem fluvial, com um amplo delta. Foram averiguados onze pontos georreferenciados em rios e riachos daquele sistema de drenagem. O uso de metodologia para coleta de dados ambientais e de peixes possibilitou descrever cada ambiente coletado bem como documentar a composição taxonômica da ictiofauna. São fornecidas ilustrações das localidades amostrais e de espécimes representativos de algumas das espécies coletadas, exibindo sua coloração em vida. No total foram verificadas 26 espécies pertencentes a 12 famílias em 6 ordens. Das espécies coletadas Trichomycterus pradensis Sarmento-Soares et al. (2005) e Mi...

This work was carried out from the assessment of the conservation status of the freshwater ichthyofauna from Bahia State. The inventory data and species distribution were obtained from the specialized scientific literature and representative ichthyological collections. A total of 281 native species was recorded in Bahia State, distributed in the Northeastern Mata Atlantica (NMA) and São Francisco (SFR) freshwater ecoregions. There was a larger number of species in the NMA (187 spp.), composed by several coastal basins, than in the SFR (134 spp.), composed by São Francisco river basin. Among the 30 families recorded, Characidae and Rivulidae were the most representative, with 53 and 48 species, respectively. The conservation status of 214 species was assessed and 33 of them (15%) were included in the IUCN threat categories. Of these, 11 species were classified as vulnerable (VU), 12 as endangered (EN), and 10 as critically endangered (CR). Most threatened species (n = 14) belongs to the family Rivulidae. The larger number of threatened species in the NMA: (n = 23) is mainly related to the high endemism of restricted-range species associated with the human occupation impacts along the coastal regions. In the SFR, most of threatened species are annual killifishes, which are locally disappearing due to increasing degradation of their temporary habitats.

The South Espírito Santo river basins include the Rio Itapemirim basin, the small river basins in Marataízes and a portion of the Rio Itabapoana basin, in Southeast Brazil. Nighty-two geo-referenced sites were sampled: 23 in Itabapoana, 66 in Itapemirim and three in Marataízes. A species list has been prepared, giving habitat details. Seventy-nine species, in 31 families and 11 orders were, reported, 17 species being from marine or brackish-water/estuarine habitats. The great majority of freshwater species belong to the Siluriformes (29 species), followed by the Characiformes (19). Torrential rivers, protected by the Caparaó mountains, display the lowest richness, with only a few species recorded from the highest valleys. On the other hand, in lowland river valleys along the Serra das Torres, an exceptional diversity of stream fishes was observed. Because of the only known population of Trichogenes claviger, a relictual species of Trichomycteridae, in the river Caxixe, this area is highly strategic in planning conservation of the Icthyofauna of the Itapemirim basin. Some species from southern Espírito Santo were described based on material collected on the historic Thayer Expedition, which crossed the region in 1865. Likewise, Oligosarcus acutirostris, Astyanax microschemos and Trichogenes claviger were also described based on fishes from southern Espírito Santo. A high endemism of freshwater species was observed between southern Espírito Santo rivers and lower Paraíba do Sul, suggesting a common history among these rivers.

Resumo -As bacias hidrográficas do norte do Espírito Santo compreendem os sistemas dos rios Itaúnas e São Mateus. O presente estudo é parte de uma série de trabalhos sobre a ictiofauna dos sistemas hídricos do Espírito Santo. Foram averiguados 49 pontos georreferenciados em rios e córregos da região, sendo 20 na bacia do rio Itaúnas e 28 na bacia do rio São Mateus. O ambiente e a composição taxonômica em cada ponto foram documentados, registrando um total de 83 espécies, sendo 47 de água doce e 36 marinhas, pertencentes a 35 famílias e 11 ordens. Dentre as espécies de água doce predominaram Siluriformes, com 20 espécies, seguida de Characiformes, com 17 espécies. A Mata Atlântica no norte do Espírito Santo, nomeada de floresta de tabuleiros, era originalmente composta por floresta ombrófila densa e ambientes de várzeas, restingas, muçunungas e manguezais. Com a devastação das florestas, a região hoje sofre com o processo de desertificação, possuindo características típicas do Semiárido nordestino, onde o escoamento das águas é esparso ou intermitente. A perda de qualidade ambiental ao longo dos vales fluviais é associada a uma necessidade premente de recuperação dos ambientes aquáticos ribeirinhos. Espécies exóticas e os riscos de introduções carecem de mais estudos nestas áreas. Espécies raras ou ameaçadas cuja distribuição foi reduzida em resposta a alterações ambientais podem funcionar como bioindicadoras. Potenciais novas espécies são assinaladas, e o endemismo regional e padrões de distribuição para peixes de água doce são discutidos. Palavras-chave adicionais: Bacia hidrográfica, biodiversidade, endemismo, ictiofauna, peixe de riacho.Abstract (Fish fauna from the basins of northern Espírito Santo, Brazil) -The hydrographic basins of northern Espírito Santo comprises the systems of Itaúnas and São Mateus rivers. The present work is part of a series of studies on the fish fauna along Espírito Santo's river basins. Forty-nine geo-referred points in rivers and rivulets of the area were evaluated, 20 in the Itaúnas basin and 28 in São Mateus basin. The environment and the taxonomic composition of the fish fauna were documented at every point, reporting a total of 83 species, including 47 freshwater species and 36 marine, belonging to 35 families and 11 orders. Among the freshwater fish species, the Siluriformes predominated, with 20 species, followed by the Characiformes, with 17 species. The Atlantic forest of northern Espírito Santo, known as "floresta de tabuleiros", was originally composed of ombrophylous forest as well as swamps, coastal sand dunes, and mangroves. With the suppression of native forests, the region has suffered from desertification, and environmental conditions are similar to the northeastern semiarid region, where the run-off waters are dispersed or intermittent. The loss of environmental quality along river valleys is associated with the need to reestablish riverine aquatic conditions. Exotic species and risks of introductions need further studies in these areas. Rare or endangered specie...

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