No abstract

Freshwater ichthyofauna from Brazil Northeast region was considered as being poorly known until recent years, with a considerable number of publications becoming available in the last decade. The present study provides an inventory of freshwater fish species from the Paraíba do Norte River basin located in Paraíba State, Brazil. This inventory is intended to contribute to the of knowledge to the regional fish diversity, pre-transposition of the São Francisco River. Collecting data was obtained from ichthyological databases of both national and foreign institutions. A total of 47 freshwater fish species are registered within the Paraíba do Norte River basin, represented by 38 genera, 20 families and six orders. Characiformes, comprising 47% (22 species), Cichliformes, and Siluriformes are among the most representative orders, 19% (9 species) each, of total recorded species. Seven species of Cichliformes are reported as introduced species in this basin. Cyprinodontiformes and Gobiiformes also registered in this region and correspond to 5% (two species) and Gymnotiformes, Perciformes and Synbranchiformes, 2% (one species each) of total recorded species. Paraíba do Norte River basin stands out in the current national scenario as it comprises the first region from the Mid-Northeastern Caatinga freshwater ecoregion to receive water from the transposition of the São Francisco River. The current inventory is important as it provides scientific data related to the ichthyofauna of Paraíba do Norte River basin prior to the commencement of the river transposition process. An identification key is also given for the freshwater fish species of the region.

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.

Ichthyological studies in coastal basins of the Mid-Northeastern Caatinga ecoregion were first conducted in the early 20th century, including collections from the Ceará-Mirim River basin, in northeastern Brazil. Besides a few systematics and ecological studies, the knowledge on fishes from this watershed is still considered partial and restricted to the freshwater portion. Thus, the objective of this paper was to conduct a comprehensive ichthyological survey of the entire Ceará-Mirim River basin, from the headwaters to the estuarine area. Fish surveys were conducted from 2011 to 2016 using varied fishing gear, resulting in the record of 63 native species (24 freshwater, 15 estuarine, and 24 marine species) and two introduced species. Four species are putatively endemic to the ecoregion, and 48 consist of new records for the basin. According to the Brazilian’s threatened fish list, three species are currently classified as ‘vulnerable’ (Megalops atlanticus, Hippocampus reidi and Mycteroperca bonaci), four as ‘near threatened’ (Kryptolebias hermaphroditus, Dormitator maculatus, Lutjanus sygnagris and L. jocu) and three as ‘data deficient’ (Cheirodon jaguaribensis, Mugil curema and Sphoeroides testudineus). The Ceará-Mirim River basin does not have any protected areas and has been suffering multiple anthropogenic impacts, however the "Centro Tecnológico de Aquicultura" (Aquaculture Technological Center) of the Universidade Federal do Rio Grande do Norte (CTA/UFRN) at the lower portion of the basin may help in the conservation of the estuarine and estuarine fish species.

Fishes from the coastal basins of the Mid-Northeastern Caatinga ecoregion (MNCE) were first sampled by the Stanford expedition at the beginning of the 20th century, and published by Edwin C. Starks in 1913. This material included specimens from the Papary lake (= Papari lagoon) in the lower portion of the Trairí river basin, draining towards the eastern coast of Rio Grande do Norte State. In 1941, Henry Fowler provided a broad taxonomic study of the freshwater fishes from northeastern Brazil, including material from the Papari lagoon, besides describing four species assigned to this locality. However, these previous surveys focused only in the lower portion of the Trairí river basin and might be incomplete. Given this framework, the present study aimed at perform a wide ichthyofaunal inventory of Trairí river basin and compared with previously surveys performed in the regions. In 2013 and 2014, four expeditions along the whole basin, including the Papari lagoon itself, resulted in 28 species of fishes belonging to 17 families and seven orders. At Papari lagoon area 16 species were registered whereas 26 and 18 species were recorded by Starks and Fowler’s studies, respectively. Considering all records, 50 species were documented in the basin with 14 (28%) new records, including Serrapinnus potiguar, whose distribution was extended to the south. Two species described by Fowler, Pimelodella papariae and Pseudancistrus papariae, were not found in this study or in any fish collection, and are only known from their type-material. These two species can be naturally rare, locally extinct, or there were inaccuracies in their type-locality. However, species of these genera are only found in larger basins of the MNCE, which drains to the north, corroborating the latter assumption. Although not being a definitive list, the recent extensive fish surveys conducted in the MNCE’s coastal basins are helping to elucidate species’ geographic distribution and little knowing taxonomic issues.

The Gurgueia River in southern Piauí state, Brazil, is the largest affluent on the right margin of the Parnaíba River basin. This study aimed to inventory the Gurgueia River ichthyofauna, and contribute to the knowledge of fish diversity in Northeastern Brazil. We sampled 71 locations throughout the Gurgueia sub-basin between 2006 and 2014, which resulted in 90 fish species representing 67 genera, 26 families and six orders, including two non-native species. Six species are newly recorded for the Parnaíba basin (Hasemania nana, Hemigrammus brevis, H. guyanensis, H. ora, Corydoras sp. and Cetopsorhamdia sp.), increasing its freshwater ichthyofauna to 152 species. The Gurgueia River contains 59.2% of the ichthyofauna known for the Parnaíba basin, and can be used as a reference point for the establishment of priority areas for the conservation of the freshwater fish fauna of the Brazilian Northeast.

Aim: Resource partitioning has been recognized as a major driver affecting fish communities, with the potential to reduce interespecific competition. This is the result of differences in feeding apparatuses and feeding mode, location of the fish species in the water column and swimming ability, as well as type and size of prey and its availability. The present study surveys a highly limited aquatic system in semi-arid Brazil with regard to habitat and food availability, with very low diversity of fish, and poor in underwater habitat structures and prey, with the objective of understanding resource partitioning among fish species under such conditions. Methods: Three species of Cichlidae (Pisces: Perciformes) were sampled during the dry and wet seasons and had their stomach contents analyzed to evaluate food consumption. The resource partition among fish species was evaluated based on Pianka's niche overlap index and tested for significance against null models. Results: It was observed a low overlap among the study species in food resource use, with individuals tending to specialize to select some food items. This is likely the result of low natural variation in abundance of specific food items associated with fish preferences (both morphological and behavioral). Conclusions: These results support evidence that, in Brazilian semi-arid aquatic systems, coexistence of fish species seems to be enhanced by the partition of food items at specific trophic levels. Within this context, flow variability would have a key hole in fish coexistence by promoting a high diversity of aquatic habitat elements available for colonization of fish and their prey. Furthermore, food resources available to fish play an important role in this dynamics since prey foods are expected to vary in abundance as the habitat changes.

O inventário da ictiofauna do rio Jaguaribe, pequena bacia costeira localizada dentro do perímetro urbano da grande João Pessoa, Estado da Paraíba revelou um total de 21 espécies de peixes, distribuídas em 18 gêneros, 11 famílias e sete ordens. Deste total, 17 espécies são de água doce e cinco marinho-estuarinas. As ordens mais especiosas foram Characiformes com nove espécies (42,8% da amostragem), todas dulcícolas, e Perciformes com seis espécies (28,5%), das quais três são dulcícolas e quatro marinho-estuarinas. Characidae foi a família com maior número de espécies (6 spp., 28,5%), seguida de Cichlidae (3 spp., 14,0%). Duas das espécies de água doce não são nativas, a tilápia (Oreochromis niloticus) e o barrigudinho (Poecilia reticulata). Das 15 espécies de água doce nativas, nove (60%) foram registradas dentro da área da Unidade de Conservação Refúgio da Vida Silvestre Mata do Buraquinho, a qual é cortada pelo curso principal do rio Jaguaribe. A riqueza de espécies registrada neste estudo (21) mostra-se similar ao que tem sido registrado em outros rios costeiros sobre influência da Mata Atlântica da ecorregião Nordeste Médio-Oriental.