267 resultados para fish species


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

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

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Pós-graduação em Zootecnia - FCAV

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

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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

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The petrochemical industry represents a sector of intense activity, in constant expansion and great economic importance for Brazil. In order to be used in various human activities petroleum needs to suffer a refinement process that, besides requiring large amounts of water, produces large amounts of wastes, which are discharged in hydric resources. Petroleum is a complex mixture mainly comprised by hydrocarbons, many of them are recognized as toxic chemicals, which are able to induce a considerable environmental pollution. Since water is an important resource for the maintenance of ecosystems and is also the final receiver of effluent discharges of the petroleum industry, there is an imminent need to monitor, constantly, the hydric resources that are influenced by this industrial activity, so that it can be ensured the environmental health. This study aimed, mainly, to analyze the quality of water samples derived from refinement process performed of the largest petroleum refinery in Brazil (REPLAN), in distinct steps of the industry treatment, and waters of rivers associated to its activity. Micronuclei and Nuclear Abnormalities tests were performed in erythrocytes of the fish species Oreochromis niloticus exposed to water samples derived from refinery use and to rivers under the influence of their effluents, in order to evaluate its possible toxic, genotoxic and mutagenic effects. The results obtained show that the treatment carried out by the refinery, during the evaluated periods, was effective, since the substances present in the water samples did not induce significant genotoxic and/or mutagenic alterations in the genetic material of the test organisms. On the other hand, when the substances present in the refinery effluent mix with the ones derived from other industrial activities developed upstream of this industry, the resultant compound, in some periods, presented genotoxic potencial, characterized by a rise of erythrocytic...

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A discussion concerning marine eutrophication, possible generated from an imbalance of fish population is presented. Simulations through a code in FORCE 2.0 considering a predator-prey model have been made and the numerical results for a three different fish species were plot in ORIGIN code. The populations considered in this study were: Sardines being prey and both mackerel and tuna being the sardine’s predators. Some hipotheses concerning to the marine eutrophication have being made according to the stages of the dynamics of the system. For situations were the prey’s populationis very low, the quality of the water experiences a strong depreciation leading to a possible eutrophication of the water.

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The state of São Paulo has four main drainages: Paraná river, Paraíba do Sul river, Ribeira do Iguape river and coastal rivers. The Paraíba do Sul river is born in Sao Paulo and drains an important range of land east of the state. Its ichthyofauna has some similarities and many differences from the continental and coastal drainages which highlights the importance of this study. Surveys conducted in the ichthyofauna of this basin, as in other large river basins in Brazil, is still incomplete. Moreover, there is no consensus about the taxonomic status of many species listed in these surveys. Considering the promising use of DNA barcode as a global system for species identification, the present study is aimed to establishing an inventory of the ichthyofauna of the São Paulo portion of the river Paraíba do Sul and simultaneously build a DNA barcode reference sequence library for fish found. Were obtained and analyzed 354 sequences of the gene cytochrome oxidase c subunit I (COI) belonging to 66 species of São Paulo portion of the Paraíba do Sul river. The average K2P distance between individuals within species of this basin was 0.48%, and 9,87% between species within a genus. Five pairs of species (10 species) showed low levels of interspecific genetic divergence (<2%),but all could be correctly identified. This study showed that the fish species analyzed could be identified efficiently through the use of barcode generating data that can provide information for further studies of this fauna, besides contributing to the global initiative to characterize the species of fish in the world of a molecular point of view. Five pairs of species (10 species) showed low levels of interspecific genetic divergence (<2%), but all could be correctly identified. This study showed that the fish species analyzed could be identified efficiently through the use of barcode generating data that can provide subsidies for further studies in this fauna, as well as ...

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The present study aimed to cytogenetic analysis and structural and molecular level of four fish species of the genus Trichomycterus: T. diabolus, T. iheringi, T. zonatus and T. cf. mimonha collected in different river basins in Brazil. Techniques were used for classical cytogenetic (Giemsa, Silver nitrate impregnation, C-banding) and molecular with the chromosomal location of genes for 18S and 5S rDNA. All individuals examined had a diploid number 54 chromosomes and karyotype consisting of types of metacentric, submetacentric and subtelocentric. The constitutive heterochromatin identified by C-banding was observed in two small blocks in the karyotype of T. diabolus and large blocks of centromeric several pairs in chromosomal karyotypes of T. iheringi, T. zonatus and T. cf. mimonha. The Silver nitrate impregnation and hybridization with 18S rDNA probe revealed the existence of only a couple carryng nucleolar organizing regions (NORs) on the species T. diabolus, T. iheringi and T. cf mimonha, and two pairs carrying 18S rDNA in T. zonatus. The 5S rDNA was observed in interstitial position 6 of the pair in T. iheringi, the synteny with the two pair in 18S rDNA of T.diabolus in pericentromeric position of and two pairs submetacentric, one being also a case of synteny with the 18S rDNA in T. zonatus and T. cf. mimonha, this rDNA was located in the pairs 3, 18 and 25, and synteny in the 18S rDNA pair 18. Although representatives of these four species Trichomycterus present diploid number and karyotypic formula preserved, three is specific about the distribuition patterns of heterochromatin and location of rDNA sequences, indicating that chromosomal differentiation events in this group of fish are acting directly on these genomic portions

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Aquaculture practices usually put the Nile tilapia in an artificial social environment, which males predominate due to their faster growth desirable for aquaculture purposes. Such a situation can increase male-male fighting because males are generally more aggressive than females, and also because fighting ability is similar within the same sex, leading to longer contests. As behavior has been used to infer welfare in several fish species, the aim of this study was to investigate whether sex composition affects agonistic interactions, social hierarchy and energetic demand in groups of Nile tilapia (Oreochromis niloticus; L.). Size-matched adult fish were divided in two treatments: MM = four males and MF = two males and two females (10 repetitions for each treatment). The experiment lasted for 11 days and social interactions (aggressiveness and rank order) were recorded at the 2nd, 6th and 10th days (15 min per day). Fish were food deprived and body weight loss was used to infer energetic cost. A higher frequency of lateral threat (Student’s t independent test; t = 2.55; p = 0.02) and total interactions (Student’s t independent test; t = -2.81; p = 0.01) was observed in the MF treatment. MM group showed unstable hierarchy (Binomial test, p = 0.04), which is considered a social stressor. However, mean weight loss was not affected by treatments (Student’s t independent test; t = -0.74; p = 0.47). These results support the idea that sexual composition affects aggressive interactions and destabilizes social hierarchy, but not energy cost

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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