42 research outputs found

    Comparação da eficiĂȘncia relativa de dois apetrechos de coleta de peixes em praias no baixo rio Purus, Amazonas, Brasil

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    Apesar das praias serem consideradas um dos sete mais importantes habitats aquĂĄticos da AmazĂŽnia, poucos trabalhos foram realizados quanto ao levantamento de sua ictiofauna, principalmente quando utilizados diferentes apetrechos de coleta. Este trabalho teve como objetivo comparar a eficiĂȘncia relativa de dois apetrechos, rede de cerco e malhadeira, ambos utilizados de forma ativa (arrasto), em trĂȘs praias localizadas no baixo rio Purus. A rede de cerco apresentou maior nĂșmero de espĂ©cies e indivĂ­duos capturados, no entanto, a malhadeira apresentou maiores valores de biomassa total, representada principalmente por Siluriformes. A baixa similaridade da fauna de peixes capturada (38%) foi devido Ă  exclusividade de espĂ©cies coletadas com cada apetrecho, 41 com rede de cerco e 32 com malhadeira. O presente trabalho mostra a importĂąncia de se utilizar diferentes apetrechos de coleta como forma de diminuir a seletividade inerente de cada um desses aparelhos, melhorando a efetividade de amostragens em ambientes pouco estudados

    New insights into the distribution and conservation status of the Golden-White Tassel-Ear Marmoset Mico chrysoleucos (Primates, Callitrichidae)

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    Among the 13 Mico species recognized by the IUCN Red List of Threatened Species, six are listed as "Data Deficient". The geographic range of most of the Mico species has been estimated from only a few records. We report new localities and the geographic extension of Mico chrysoleucos. In addition, we confirmed the presence of the species in two distinct protected areas. We modeled the habitat suitability of M. chrysoleucos using the maximum entropy method and including new records obtained by the authors in the state of Amazonas, Brazil. From the total area of occurrence calculated for the species, 22.8% is covered by protected areas and indigenous lands. The annual mean deforestation rate estimated between 2000 and 2015 was 2.95%, and the total area deforested by 2015 was 3354 km2 or 8.6% of the total distribution limits of the species. The habitat lost between 2000 and 2015 was 3.2% (1131 km2 ) of the total potential distribution, while the habitat loss area legally protected was 31 km2, and the habitat loss in settlements was equal to 691 km2. Our results extend the geographic distribution of the species about 100 km farther south, with the Maracanã River being a possible geographic barrier for the species. The significantly low rate of habitat loss inside protected areas and indigenous land, when compared to unprotected areas, points out the importance of these areas to M. chrysoleucos conservation. The species is relatively wide-ranging, legally protected, and resilient to regional anthropic threats. However, the hydroelectric schemes and the improvement of the road system in southern Amazonia pose an imminent threat to the species

    A small new species of Crenicichla Heckel, 1840 from middle rio Xingu, Brazil (Teleostei: Cichlidae)

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    A new species of Crenicichla is described from the middle rio Xingu and tributaries, upstream from Volta Grande do Xingu. The largest specimen measured 47.8 mm SL. The new species can be distinguished from all other Crenicichla species by the combination of the following character states: presence of serrae on supracleithrum (diagnostic of Crenicichla wallacii species group), large caudal blotch centrally located on caudal lateral line (shared with C. urosema and C. virgatula), vertical dark stripes on the caudal fin and up to three series of teeth on premaxilla and maxilla (vs. more than four series of teeth). The new species described herein is the eleventh species of Crenicichla listed from the rio Xingu basin. Similarities of color pattern among small species of Crenicichla is discussed. © 2015, Sociedade Brasileira de Ictiologia

    Dimorfismo sexual em Siluriformes e Gymnotiformes (Ostariophysi) da AmazĂŽnia

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