564 research outputs found
The ichthyofauna of the marginal lagoons of the Sorocaba River, SP, Brazil: composition, abundance and effect of the anthropogenic actions
Feeding biology of a guild of benthivorous fishes in a sandy shore on south-eastern Brazilian coast
Niche divergence facilitated by fine-scale ecological partitioning in a recent cichlid fish adaptive radiation
Ecomorphological differentiation is a key feature of adaptive radiations, with a general trend for specialization and niche expansion following divergence. Ecological opportunity afforded by invasion of a new habitat is thought to act as an ecological release, facilitating divergence, and speciation. Here, we investigate trophic adaptive morphology and ecology of an endemic clade of oreochromine cichlid fishes (Alcolapia) that radiated along a herbivorous trophic axis following colonization of an isolated lacustrine environment, and demonstrate phenotype-environment correlation. Ecological and morphological divergence of the Alcolapia species flock are examined in a phylogenomic context, to infer ecological niche occupation within the radiation. Species divergence is observed in both ecology and morphology, supporting the importance of ecological speciation within the radiation. Comparison with an outgroup taxon reveals large-scale ecomorphological divergence but shallow genomic differentiation within the Alcolapia adaptive radiation. Ancestral morphological reconstruction suggests lake colonization by a generalist oreochromine phenotype that diverged in Lake Natron to varied herbivorous morphologies akin to specialist herbivores in Lakes Tanganyika and Malawi
Comparative feeding ecology and habitats use of Crenicichla species (Perciformes: Cichlidae) in a Venezuelan floodplain river
Diel variation in the ascent of fishes up an experimental fish ladder at Itaipu Reservoir: fish size, reproductive stage and taxonomic group influences
Challenge of pacu (Piaractus mesopotamicus) fed diets supplemented with vitamins C and E by Aeromonas hydrophila under different temperature
Guianacara dacrya, a new species from the rio Branco and Essequibo River drainages of the Guiana Shield (Perciformes: Cichlidae)
Reproduction of Oligosarcus hepsetus (Cuvier, 1829) (Characiforms) in the Serra do Mar State Park, São Paulo, Brazil
Comparação da eficiência relativa de dois apetrechos de coleta de peixes em praias no baixo rio Purus, Amazonas, Brasil
Apesar das praias serem consideradas um dos sete mais importantes habitats aquáticos da Amazônia, poucos trabalhos foram realizados quanto ao levantamento de sua ictiofauna, principalmente quando utilizados diferentes apetrechos de coleta. Este trabalho teve como objetivo comparar a eficiência relativa de dois apetrechos, rede de cerco e malhadeira, ambos utilizados de forma ativa (arrasto), em três praias localizadas no baixo rio Purus. A rede de cerco apresentou maior número de espécies e indivíduos 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 à exclusividade de espécies coletadas com cada apetrecho, 41 com rede de cerco e 32 com malhadeira. O presente trabalho mostra a importância 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
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