The Parnaíba River is the largest hydrographic basin with its limits entirely within the northeastern region of Brazil. It is one of the few perennial rivers in the Brazilian Northeastern Region, running predominantly in the area of Caatinga on the eastern portion (with intermittent drainages associated to this type of environment), and partly extending into the Cerrado region on the western portion. The objective of this study was to describe the diversity of freshwater fishes of the Parnaíba River basin by conducting a comprehensive ichthyofauna inventory of the basin. The sampling design of this study was based on the placement of (1) Fixed Sites for seasonal collection (dry and wet season, two years) in the three portions of the main course of the Parnaíba River, and (2) ''Aquarap'' protocol collections which covered the entire basin. The collection effort consisted of 244 sampling sites surveyed along the entire basin between the years 2004 and 2011. Fish were collected with the use of seines, cast nets, gill nets and dip nets; only the first two fishing gears were used in Fixed Sites. As a result, 146 species of freshwater fish were recorded in the Parnaíba River basin, distributed in 103 genera, 36 families and 11 orders. The registered endemism reached a total of 54 species.

Abstract:The Seridó /Borborema region is located between the States Paraíba and Rio Grande do Norte and a priority area for conservation of the Caatinga. This region is under the hydrological influence of the middle portion of Piranhas-Açu River basin. Previous systematic inventories of the ichthyofauna of this Caatinga's area are not significant. The Caatinga fish fauna is threatened due the advancement of historic anthropogenic activities, mainly agricultural. Furthermore, another relevant aspect is the recent governmental decision of transferring water from Sã o Francisco River to other Northern river basins, which includes the Piranhas-Açu basin. This study performed a systematic survey of the Seridó / Borborema's ichthyofauna. The sites were sampled during the years 2006 and 2007 (four annual, diurnal samples), using three different types of gear: beach seine nets, cast net and gillnets. We captured 13,009 individuals of 5 orders, 14 families, 28 genera and 35 species of fish. The predominant orders were Characiformes (21 species), Siluriformes (6) and Perciformes (5). The greatest number of species (11) was catch from the family Characidae, followed by Cichlidae (5) and Loricariidae (4). This inventory produced a comprehensive sampling of the middle portion of Piranhas-Açu River basin and its result overcomes the diversity reported in previous studies (22 species) on the same region. Keywords: Inventory, Fish, Piranhas-Açu River, Caatinga, Northeastern Brazil.Resumo: A regiã o Seridó /Borborema, localizada entre os Estados da Paraíba e do Rio Grande do Norte, é uma á rea prioritá ria para conservaçã o da Caatinga e encontra-se sob domínio hidroló gico da porção média da bacia do rio Piranhas-Açu. Levantamentos sistemá ticos sobre a ictiofauna desta região da Caatinga realizados até esse momento sã o pouco expressivos. A ictiofauna da Caatinga sofre ameaças devido ao avanço histó rico de atividades antró picas, principalmente agropastoris. Além disso, outro aspecto que merece destaque é a recente implantaçã o da obra de integraçã o do rio Sã o Francisco com as bacias hidrográ ficas do Nordeste Setentrional. O presente estudo realizou um levantamento sistemá tico da ictiofauna da regiã o Seridó /Borborema. As amostragens foram realizadas entre os anos de 2006 e 2007 (quatro amostragens anuais diurnas), utilizando redes de arrasto, tarrafa e redes de emalhar. Foram capturados 13.009 indivíduos pertencentes a 5 ordens, 14 famílias, 28 gêneros e 35 espécies de peixes. As ordens predominantes foram Characiformes (21 espécies), Siluriformes (6) e Perciformes (5). Characidae foi a família com o maior nú mero de espécies (11), seguida por Cichlidae (5) e Loricariidae (4). Este inventá rio produziu uma abrangente amostragem da porção média do rio Piranhas-Açu e seu resultado supera a diversidade registrada em estudos prévios (22 espécies) da mesma região. Palavras-chave: Inventário, Peixe, Rio Piranhas-Açu, Caatinga, Nordeste Brasileiro.

Effects of riparian vegetation removal on the structure of the marginal aquatic habitat and the associated fish fauna in a tropical Brazilian reservoir. Biotra Neotrop., 9(4): http://www.biotaneotropica.org.br/v9n4/en/abstract?article+bn00709042009.Abstract: Riparian zones represent areas of strong biological, physical and chemical interaction between terrestrial and aquatic ecosystems. These areas are usually typified by high diversity of fauna, flora and environmental processes. The present study evaluates the littoral habitat structure and its fish fauna related to associations between presence and absence of natural riparian vegetal cover, in a reservoir in northeastern Brazil. Sampling was performed on marginal areas where riparian vegetation was present and where it had been removed for the plantation of sugar cane. For each type of marginal area three replicate sites were sampled during the wet season. Data on the habitat structure (submerged elements and substrate composition), fish and water quality were collected. The data was analyzed using Shannon-Wiener's diversity index and Pielou's equitability. Non-metric Multidimensional Scaling and the Multi-Response Permutation Procedure were used to evaluate similarities between sites. The structure of the habitat was more diverse in sites were natural riparian vegetation was still present. Muddy substrate was more abundant in areas with riparian vegetation whereas sandy substrate was more abundant in areas where riparian vegetation had been removed. Measured physico-chemical parameters and nutrients remained nearly constant across all sites. Metynnis lippincottianus and Crenicichla menezesi were more associated with the habitat in areas where riparian vegetation was removed, whereas Cichlasoma orientale and Cichla ocellaris were strongly correlated to forested areas. Keywords: riparian zone, habitat structure, water management, conservation.BELTRÃO, G. B. M., MEDEIROS, E. S. F. & RAMOS, R. T. C. Efeitos da cobertura vegetal ripária na estrutura do habitat aquático marginal e na fauna de peixes associada em um reservatório tropical brasileiro. Biotra Neotrop., 9(4): http://www.biotaneotropica.org.br/v9n4/pt/abstract?article+bn00709042009.Resumo: A zona ripária representa uma área de importantes interações, sejam biológicas, físicas ou químicas, entre o ecossistema terrestre e aquático. Essas áreas são geralmente caracterizadas por uma alta diversidade de fauna, flora e processos ecológicos. Este estudo avalia a estrutura do habitat aquático e a fauna de peixes com relação à presença e ausência da mata ciliar natural em um reservatório no Nordeste brasileiro. Amostragens foram realizadas em áreas marginais onde a mata ciliar estava presente e onde esta havia sido removida para o plantio de cana-de-açúcar. Em cada área, três pontos de coleta foram amostrados durante o período chuvoso. Dados sobre a estrutura do habitat (elementos submersos e composição do substrato), peixes e qualidade da água foram coletados. Os dados foram analisados usando o índice de divers...

The Mamanguape River Basin is located in a peripheral semi-arid area of South America, with its headwaters and middle reaches running through the Caatinga (from wetter to drier) and its lower reaches through the Atlantic Forest. The objective of this study was to inventory the fish fauna of the Mamanguape river basin through a comprehensive sampling and to discuss its ichthyofaunal dominance pattern. Sampling was conducted between 2015 and 2016 at 38 points throughout. The main river course was sampled at 18 fixed points during two expeditions (dry and wet seasons) using traw nets, cast nets, and dip nets, with a standardized effort. The tributaries were sampled during the dry season at 20 points using an adaptaptation of the AquaRAP methodology. A total of 32 freshwater fish species belonging to 26 genera, 16 families and six orders were recorded, predominantly from the order Characiformes and the family Characidae. Astyanax fasciatus had widest distribution and greatest abundance in the basin. Siluriformes were the second most prevalent order, with five species recorded. Cichla cf. monoculus, Poecilia reticulata and Oreochromis niloticus were non-native records for the basin. Apareiodon davisi, an Endangered species, was recorded.

Hypostomus johnii (Steindachner) was described from the rio Parnaíba basin in the state of Piauí and the rio São Francisco basin in the state of Bahia. Despite the good quality of the original description of H. johnii, it does not currently allow its distinction from congeners. Thus, H. johnii is redescribed based on the analysis of the types and several recently collected specimens. Recent collecting efforts of the rios Parnaíba and São Francisco basins resulted in specimens only being found in the rio Parnaíba basin. This raises doubts about whether H. johnii occurs in the rio São Francisco basin. The species is distinguished from its congeners by having a high number of teeth on the premaxilla and dentary (between 60-115); small to moderate-sized dark spots with a light background; absence of keels on flanks; and abdominal plates more evident on laterals. A lectotype of H. johnii is designated herein and H. eptingi is considered a junior synonym of H. johnii.Keywords: Armoured catfish, Freshwater fish, Hypostominae, Neotropical fish, Taxonomy.Hypostomus johnii (Steindachner) foi descrita a partir de espécimes da bacia do rio Parnaíba, no Estado do Piauí e da bacia do rio São Francisco, no Estado da Bahia. Apesar da descrição original de H. johnii ter sido adequada para a época, esta não permite atualmente a sua diferenciação dos outros congêneres. Portanto, H. johnii é redescrita, baseado na análise dos tipos e de espécimes recentemente coletados. Recentes esforços de coleta nas bacias do rios Parnaíba e São Francisco resultaram em espécimes coletados apenas na bacia do rio Parnaíba. Este fato coloca em dúvida a ocorrência de H. johnii na bacia do rio São Francisco. Hypostomus johnii é diferenciada de seus congêneres principalmente por possuir um elevado número de dentes no pré-maxilar e dentário (entre 60-115), por apresentar pequenas manchas escuras de tamanho moderado sobre um fundo claro; ausência de quilhas sobre flancos; e as placas do abdômen mais evidente nas laterais. Um lectótipo para H. johnii é aqui designado e H. eptingi é considerado sinônimo júnior de H. johnii.