Morphological aspects of Henneguya aequidens n. sp (Myxozoa: Myxobolidae) in Aequidens plagiozonatus Kullander, 1984 (Teleostei: Cichlidae) in the Amazon region, Brazil

A new species of Myxosporea, Henneguya aequidens sp. n. (Myxozoa: Myxobolidae), was described based on its ultrastructural features. This is a parasite of the freshwater fish Aequidens plagiozonatus, in the Peixe-boi River, Para, Brazil. This parasite was found in the gills, in the form of whitish ellipsoid cysts with mature spores inside them. The average spore body was 15 +/- 0.9 mu m in length (n = 30) and 6 +/- 0.8 mu m in width (n = 30), and the tail measured 27 +/- 0.5 mu m in length (n = 15). The spores showed typical features of the genus Henneguya with two valves of equal size and two symmetrical polar capsules of 3 +/- 0.3 mu m in length and 2 +/- 0.3 mu m in width. Each polar capsule had a polar filament forming a helix from the apical region to the polar caps, with four to six turns. Based on the ultrastructural differences in morphology of these spores, the location of the parasite, and its host specificity, this parasite was described as a new species.

Anti-androgenic activities of diuron and its metabolites in male Nile tilapia (Oreochromis niloticus)

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

The importance of a Biosphere Reserve of Atlantic Forest for the conservation of stream fauna

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Parasitism by Sphincterodiplostomum musculosum (Digenea, Diplostomidae) metacercariae in the eyes of Steindachnerina insculpta (Characiformes, Curimatidae)

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Cytogenetic and molecular data demonstrate that the bryconinae (ostariophysi, bryconidae) species from southeastern Brazil form a phylogenetic and phylogeographic unit

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Utilização do sistema de bioflocos na larvicultura de Tilápia-do-Nilo

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Análise de parentesco e variabilidade genética de pacu (Piaractus mesopotamicus) por meio de marcadores SNPs: subsídios para o melhoramento genético

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Estrutura da comunidade parasitária de duas espécies de peixes autóctones da RPPN Foz do rio Aguapeí, Alto rio Paraná

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

The 5S rDNA family evolves through concerted and birth-and-death evolution in fish genomes: an example from freshwater stingrays

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Reduction of a native fish fauna by alien species: an example from Brazilian freshwater tropical lakes

The consequences of introducing Cichla cf. monoculus Spix & Agassiz, Astronotus ocellatus (Agassiz) and Pygocentrus nattereri Kner into lakes in the River Doce basin, Brazil, on richness, diversity and efficiency of aquatic macrophytes as natural refugia to native fishes was investigated. Samples were taken from lakes with and without alien fishes in areas with and without aquatic macrophytes. The presence of alien fishes reduced richness and diversity of the native fish community. The refugia function, which could be attributed to the clustering of aquatic macrophytes, does not exist in these lakes probably because the alien fishes exploit such habitats for reproduction. Since introductions threaten the native fish diversity of the region, studies on regional dispersion and factors that minimise the spread of alien fishes are needed.

Population genetic structure revealed by a school of the freshwater migratory fish, Brycon hilarii

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Feeding level and frequency for freshwater angelfish

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Effect of Salinity on Larval Rearing of Pacu, Piaractus mesopotamicus, a Freshwater Species

The aim of this study was to evaluate the growth and survival of pacu, Piaractus mesopotamicus, larvae reared in different salinities and to determine the Artemia nauplii life span in freshwater and in saline water. First feeding 5-d-old pacu larvae were reared in freshwater or at 2, 4, 6, 8, 10, 12, and 14 ppt salinities. The larvae were reared in 1.5-L aquaria at a density of 10 larvae/L with three replicates per treatment. After 10 d of rearing, significant differences (P < 0.05) were observed for growth and survival. Larval growth was higher at 2 and 4 ppt, and survival at 2 ppt was 100%. In freshwater and at 4, 6 and 8 ppt, the survival was 91.1, 93.3, 73.3, and 39.9%, respectively. At higher salinities, there was 100% mortality after 2 h (12 and 14 ppt) and 8 h (10 ppt) of exposure. The slightly saline water of at least 2 ppt increased the Artemia nauplii life span compared to the life span in freshwater. Later, in a second trial, 5-d-old pacu larvae were reared in freshwater and at 2 and 4 ppt salinities during the first 5 or 10 d of active feeding, and then the fish were transferred to freshwater. At the end of 15 d, larval growth was lower in freshwater (42 mg) than in treatments 2 and 4 ppt (5963 mg). The abrupt transfer of fish from freshwater to slightly saline water and the return to freshwater did not affect the survival rates (8997%). The larvae were able to adapt to these saline environments and handle abrupt changes in salt concentration. We concluded that salinity concentration of 2 ppt can be used for pacu larval rearing, allowing the Artemia nauplii lifetime to last longer and cause faster fish growth.

Testicular structure and spermatogenesis of Amazonian freshwater cururu stingray Potamotrygon cf. histrix

The cururu stingray Potamotrygon cf. histrix, a new and endemic Amazonian freshwater species, presents appropriate characteristics for fish keeping and is exploited from its natural environment. The present study identified the testicular structure and spermatogenesis of this species. Gonads from adult male specimens were dissected, fixed and processed for histological analysis. The testes were of testicular/epigonial type. The presence of germinal papillae was observed in the upper portion of organ with primordial germ cells and Sertoli cell precursors. The testis was lobular with zonal organization and cystic gametogenesis, with the occurrence of spermatoblasts. The Sertoli cells underwent morphological modifications over the course of gamete formation. The spermatozoids had long heads and were spiraled on their own axis. Information on the reproductive biology will serve as basis for studies on the reproduction and phylogeny of this peculiar group of cartilaginous fish.

Trauma and envenoming caused by stingrays and other fish in a fishing community in Pontal do Paranapanema, state of São Paulo, Brazil: epidemiology, clinical aspects, and therapeutic and preventive measures

INTRODUÇÃO: Os acidentes causados por peixes são comuns em comunidades de pescadores fluviais no Brasil, sendo acidentes ocupacionais na maioria das vezes. Estas populações não têm informações dos mecanismos de trauma e envenenamento. MÉTODOS: Através de um questionário aplicado aos pescadores, foram obtidos dados clínicos e epidemiológicos sobre acidentes em Rosana, Pontal do Paranapanema, Estado de São Paulo, Brasil. Estes dados foram analisados e convertidos em um programa de prevenção e tratamento de acidentes através de um folheto de fácil assimilação RESULTADOS: Trinta e nove pescadores responderam o questionário. Todos os pacientes apresentaram ferimentos causados por algum peixe. Dos peixes mencionados, mandijubas (Pimelodus maculatus) foram os mais associados aos ferimentos, mas outros também causaram traumas. em relação às arraias, seis pescadores tinham sido envenenados. Dor intensa e úlceras foram os principais sintomas. Aproximadamente metade dos acidentados usou apenas medidas de tratamentos populares. CONCLUSÕES: Os pescadores apresentaram acidentes múltiplos por mandis, que são peçonhentos e causam dor intensa, assim como traumas por outros peixes, como surubins, traíras, corvinas de água doce e piranhas. Cerca de 16% dos entrevistados apresentaram envenenamento por arraias. Nossos dados e experiência prévia permitiram a criação de um folheto de fácil assimilação pelas populações locais que pode ajudar os pescadores de forma efetiva, em uma área extremamente carente de serviços de saúde e prevenção de doenças. Esta iniciativa é aplicável a toda a bacia do Rio da Prata, área extensa e de fauna similar.