58 resultados para Pimelodus maculatus

em Repositório Institucional UNESP - Universidade Estadual Paulista "Julio de Mesquita Filho"


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

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This study analyses the ontogenetic diet shifts of a Neotropical catfish, Pimelodus maculatus ( Siluriformes, Pimelodidae), from an ecomorphological standpoint. We collected 241 individuals in the Piracicaba River ( Brazil) and, in the laboratory, seven morphometric variables were recorded from each specimen: standard length (SL), body depth, head length, snout length, eye diameter, mouth height and mouth width. After standardizing these measurements ( as a proportion of SL), linear regressions were run to determine whether their growth was isometric or allometric in relation to SL. The diet analysis shows that the main food item for fish in the smaller size classes is aquatic insects, while the largest individuals feed mainly on other fish. As the great majority of the morphometric variables analyzed showed isometric growth as a function of SL - which means that these fish do not change their shape significantly during their lives - the ontogenetic diet shifts may be seen as a consequence of the absolute size increment of their mouth gape, which allows individuals to maximize their energetic gain by ingesting larger prey with a higher caloric content.

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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A number of 170 individuals of the species Pimelodus maculatus, a Neotropical fish known as mandi was collected in three distinct locations of the Piracicaba river (Piracicaba, Santa Maria da Serra and Americana – SP0 from April 2009 to February 2010. A common species of catfish whose individuals exist in many neotropical basins was observed to get more information about a possible influence of the water conditions in distant parts of a same river to its condition and also to verify whether the stomach contents of fish collected in these distinct places may distinguish as a possible consequence of food availability. The species were studied by collecting biological data such as standard length (SL) in cm, their total weights (TW ) in grams and sexes to see the composition of fish present in the samples. Length-weight relationships are important means to investigate facts related to the condition of the species in these systems. The analysis was made by using covariance to observe if individuals of similar lengths collected in distinct places may be compared to this purpose. Usual methods to investigate relationships of stomach food contents were applied. By analyzing the condition factor, one may conclude that the mandis collected in the region of Santa Maria da Serra presented similar characteristics to those obtained in Piracicaba, but they differ in this aspect for individuals collected in Americana. This fact is not conclusive about the reasons of this situation, but it may be a first step to other studies in order to get more information about. The degree of stomach repletion may be a first approach to this possible explanation, as individuals of Piracicaba presented usually full stomachs and differed in this way to individuals collected in the two other places

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The species Pimelodus maculatus is one of the most abundant fish in many artificial reservoirs. Shows feeding plasticity and exploits all trophic levels in aquatic ecosystems. This study aimed to analyze and compare aspects of the diet of P. maculatus in two important tributaries (Taquari and Veados rivers) in the upper Paranapanema River system, and also investigate possible differences in the condition factor using its feeding habit as reference. Samplings were carried out every three months during 2011 and 2012 in two tributaries of Jurumirim's dam. After biometric analysis, fish were dissected to remove the stomachs that were fixed in formaldehyde 10% and conserved in alcohol 70%. The stomach content was analyzed under stereomicroscope and the food items were identified until the least possible taxonomic level. The diet was characterized based on the Alimentary Index (IAi). Feeding strategy and aspects of species autoecology were evaluated by the relation between abundance of prey-specific (Pi) and occurrence frequency (Fo) of the prey, and also was calculated the niche width of Levin (B). The condition factor was also established and values obtained in samples of both rivers were compared, correlating them with diet of the species

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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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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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.

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

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)