O uso de fontes alimentares basais e sua assimilação energética como base para explicar o estabelecimento de uma espécie de peixe invasora em planície de inundação sob impacto de reservatórios.

• Autor(a) principal: Pazianoto, Laryssa Helena Ribeiro
• Data de Publicação: 2015
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: Repositório Institucional da Universidade Estadual de Maringá (RI-UEM)
• Texto Completo: http://repositorio.uem.br:8080/jspui/handle/1/4877
• topic: Hemiodus orthonops (Characiformes: Hemiodontidae) "bananinha"; Espécie invasora; Fluxo energético; Cadeia trófica; Densidade energética; Fator de condição relativo; Detritivoria; Invasões biológicas; Ecologia energética; Planície de inundação; Alto rio Paraná; Brasil.; Energetic density; Relative condition factor; Detritivory; Biological invasions; Hemiodus orthonops; Upper Paraná River; Floodplain; Brazil.; Ciências Biológicas; Ecologia

Diet analysis, energy density (ED) and relative condition factor (Kn) were applied to the invasive fish Hemiodus orthonops data in order to investigate the energetic assimilation of the species under different environmental condition of the three subsystems of the upper Paraná river floodplain. The following hypotheses were tested: 1) H. orthonops uses different food resources in each of the subsystems due to physicochemical differences and; 2) the highest ED and Kn are found in the tributaries, due to their higher conservation status. Samples were taken in June and September 2013 and 2014 in nine sites. Nutrient content was determined for sediment samples. The diet was determined through stomach content analysis and combined in the Food Index (IAi%), ED was obtained from each individual muscle tissue and expressed in Kcal/g of dry weight, Kn was calculated by: Kn = Wt/We. Subsystem Baía presented high aluminum concentration on sediment samples, as well as lower pH values. Detritus/sediment prevailed in the stomachs of specimens from Ivinhema and Baía due to higher organic matter input in these systems, while Algae was the main item in Paraná, due to higher water transparency. The species did not present feeding restrictions, consuming the available items in each subsystems, favoring its establishment. ED and Kn from Ivinhema specimens were higher, reflecting the conservation status. Lower ED were recorded for Paraná specimens because of increased predation risk due to higher water transparency. Higher Kn in this subsystem are due to algae consumption, a nutrient-rich food resource. The lower ED and Kn recorded for Baía specimens are due to lower pH that reduce the density and activity of microorganisms and the nutritional value of the detritus, besides, higher aluminum concentration are toxic and can deviate energy from somatic growth. Even though Paraná subsystem presents more negative impacts, related to dams effects, it is perfectly suitable for H. orthonops development and establishment. The food resources available in all subsystems favor their reproduction, assuring continuous dispersion of the species in the floodplain.