Individuals of four species of Leporinus were captured in the floodplain of the Upper Paraná River and their metazoan parasites were collected. Fifty-eight taxa of ectoparasites and endoparasites were recorded: 31 in Leporinus lacustris, 32 in Leporinus friderici, 28 in Leporinus obtusidens and 25 in Leporinus elongatus. The aim of this paper was to study the relationship between the host's condition and the parameters of infrapopulations and infracommunities. The health of the host was represented by the relative condition factor (Kn). Richness and number of individuals in the infracommunities of ectoparasites covariated with the Kn of the hosts in one species of fish. Some infrapopulations of ectoparasites covariated negatively and/or the mean Kn of parasitized individuals was lower than those without parasites. The abundance in some infrapopulations of endoparasites covariated positively with the Kn and/or the mean Kn of parasitized fish was better. These results may be related to different transmission strategies used by ecto and endoparasites.

Photosynthesis and growth of Egeria najas (Hydrocharitaceae) from a subtropical reservoir (Itaipu Reservoir, Brazil-Paraguay)

The trematode Phyllodistomum thunni is recorded here for the first time in the marine fish Macrodon ancylodon (Perciformes, Sciaenidae), king weakfish, from the Brazilian coast, South Atlantic. The fish were caught in the region of Valença, Bahia, Brazil, between August 2009 and May 2010, to study its parasite fauna. Seventy-four fish were examined and the kidney ducts of 11 of them were found to be parasitized by this trematode. The parasite prevalence was 14.8%; the mean intensity was 2.7 parasites per fish and the infrapopulations ranged from 1 to 5 parasites. Phyllodistomum thunni was originally described in yellowfin tuna, Thunnus albacares, from the Gulf of Guinea. Therefore, the geographic distribution and the host range of gorgoderid trematode have been expanded.

The indiscriminate use of synthetic veterinary drugs in fish farms for disease control has caused recurring environmental pollution and reduced productivity; however, the search for ecologically viable alternatives is increasing. Thus, this study aimed to evaluate the phytochemical characterization of the hexanic, methanolic, and aqueous extracts of black jurema (M. tenuiflora), and their antimicrobial activity against strains of Aeromonas, and acute toxicity (LC50) to fingerlings of O. niloticus. The isolates were identified, and phenotypic virulence and antimicrobial susceptibility tests were performed. A. caviae, and A. veronii bv. veronii showed 75.0 - 87.5% positivity for the virulence factors tested, and resistance to the antimicrobials ampicillin, amoxicillin, erythromycin, and tetracycline of 67.0% and 50.0%, respectively. Phytochemical screening of black jurema extracts detected phenols, flavonoids, tannins, saponins, alkaloids, and steroids/triterpenoids, with methanol proving to be more efficient in the extraction of metabolites. The methanolic and aqueous extracts showed moderate antimicrobial activity, with minimum inhibitory concentration and minimum bactericidal concentration of 250 μg mL-1, and the methanolic extract revealed an LC50 of 40 μg mL-1 for O. niloticus. This study demonstrated the efficiency of the in vitro antimicrobial activity of M. tenuiflora extracts, and their use in vivo in the treatment or prophylaxis in fish farming can be investigated to replace the use of synthetic antimicrobials.

A etnoparasitologia é uma área de estudo que relaciona-se diretamente com a etnoecologia uma vez que, por definição, o parasitismo é considerado uma das relações simbióticas entre seres vivos. A ictioparasitologia pode ser estudada sob este prisma, avaliando-se o modo como as populações ribeirinhas compreendem as doenças parasitárias dos animais dos quais dependem para sua subsistência. Esta pesquisa objetivou analisar o conhecimento tradicional de pescadores dos municípios de Nazaré e Jaguaripe, Bahia, que realizam pesca no Rio Jaguaripe, sobre as interações peixes-parasitos, visando observar a percepção da ocorrência de parasitos, da influência desses organismos sobre os peixes, da dinâmica do parasitismo (sazonalidade, ciclo de vida) e da relação dos parasitos de peixes com o ser humano e com possíveis zoonoses. A seleção dos pescadores deu-se por amostragem tipo bola de neve e a coleta de dados por meio de questionário aberto e semiestruturado. Foram entrevistados 27 pescadores sendo os dados analisados qualitativamente e quantitativamente. Os resultados obtidos de ambas as comunidades apontam para um conhecimento de pelo menos dois grupos zoológicos de parasitos: Crustacea e Nematoda. Indicam reconhecimento de aspectos como sazonalidade, patologias e biologia parasitária. Também demonstrou que os pescadores percebem parasitos principalmente daqueles peixes de interesse comercial e não consideram a possibilidade de parasitos de peixes causarem doenças em humanos.

A etnoparasitologia é uma área de estudo que relaciona-se diretamente com a etnoecologia uma vez que, por definição, o parasitismo é considerado uma das relações simbióticas entre seres vivos. A ictioparasitologia pode ser estudada sob este prisma, avaliando-se o modo como as populações ribeirinhas compreendem as doenças parasitárias dos animais dos quais dependem para sua subsistência. Esta pesquisa objetivou analisar o conhecimento tradicional de pescadores dos municípios de Nazaré e Jaguaripe, Bahia, que realizam pesca no Rio Jaguaripe, sobre as interações peixes-parasitos, visando observar a percepção da<strong> </strong>ocorrência<strong> </strong>de<strong> </strong>parasitos<strong>, </strong>da<strong> </strong>influência desses organismos sobre os peixes, da dinâmica do parasitismo (sazonalidade<strong>, </strong>ciclo<strong> </strong>de<strong> </strong>vida) e da relação dos parasitos de peixes com o ser humano e com possíveis zoonoses. A seleção dos pescadores deu-se por amostragem tipo bola de neve e a coleta de dados por meio de questionário aberto e semiestruturado. Foram entrevistados 27 pescadores sendo os dados analisados qualitativamente e quantitativamente. Os resultados obtidos de ambas as comunidades apontam para um conhecimento de pelo menos dois grupos zoológicos de parasitos: Crustacea e Nematoda. Indicam reconhecimento de aspectos como sazonalidade, patologias e biologia parasitária. Também demonstrou que os pescadores percebem parasitos principalmente daqueles peixes de interesse comercial e<strong> </strong>não consideram a possibilidade de parasitos de peixes causarem doenças em humanos.

The rio da Dona is an important water body in the Recôncavo Sul basin used as a water supply for the neighboring towns and for agriculture, recreation and subsistence fishing. The knowledge about the ichthyofauna of this river is scarce. In this paper, an inventory of the fish fauna from rio da Dona basin and an identification key for the species recorded are presented. Additionally, taxonomic and conservationist issues are discussed. The specimens were collected in different sites along the upper, middle and lower courses of the rio da Dona. The fishes were anesthetized, fixed in formalin, conserved in ethanol, and identified. In addition to the material collected, specimens previously deposited in the ichthyological collection of the Museu de História Natural da Bahia were also analyzed. Twenty species, distributed into 16 genera, ten families, and four orders were recorded. One of these species, Aspidoras kiriri, is endemic to the rio da Dona. Four species, Cichla pinima, Coptodon rendalli, Poecilia reticulata and Serrasalmus brandtii, have been introduced into the river. Higher richness of native species has been recorded in the upper course of the rio da Dona, while in the middle and lower parts non-native species were also representative. Along the river, a series of anthropic impacts were observed, such as deforestation of native forest including the riparian vegetation, silting and dams, which can probably compromised the resident ichthyofauna.