Submitted by Ricardo Cedraz Duque Moliterno (ricardo.moliterno@uefs.br) on 2015-07-31T21:05:08Z No. of bitstreams: 1 Disserta??o Final_Luis Rog?rio.pdf: 923746 bytes, checksum: ea087faabdb4f49cb27f0e415afb0a25 (MD5) / Made available in DSpace on 2015-07-31T21:05:08Z (GMT). No. of bitstreams: 1 Disserta??o Final_Luis Rog?rio.pdf: 923746 bytes, checksum: ea087faabdb4f49cb27f0e415afb0a25 (MD5) Previous issue date: 2013-02-04 / The inclusion of artificial barriers in freshwater ecosystems can trigger ecological, economic and social processes, affecting them. The food plasticity is an adaptive feature to the new environment, it is expected that the food of fish species under modified atmospheres follows changes in nutrient availability in the environment. To evaluate whether among the different phases of construction of Estreito barrage, Tocantins River, MA there are differences in the dietary habits of the family Cichlidae, collecting expeditions were conducted from November 2009 to 2010, (river stage) and November 2010 to April 2011 (filling phase), with an average duration of 10 days per year. The food items of dominant cichlid were analyzed using frequency and volume index, combined in Alimentary Index(IAI). The Shannon index was used to evaluate the diversity of items and classification of trophic guild. Significant differences in amplitude niche between the river and filler phases were verified by testing Hutcheson. Among cichlids found in fishes and alga influences barrage area, Geophagus proximus and Cichla proximus piquiti were dominant, being examined 26 specimens of Geophagus proximus in river stage and 6 specimens in filling stage, with results suggesting an omnivorous diet, predominantly f item in river stage and insects item for filling phase. The Cichla piquiti were examined 28 specimens in river stage and 32 specimens during stage filling, suggesting a piscivorous diet in both phases of the barrage. The number of food categories ranged between 09, during river phase and 08 the filling phase to Ciclha piquiti and between 14 during river phase and 12 the filling phase to Geophagus proximus. The test of difference in niche amplitude between the two phases revealed a nonsignificant difference for Cichla piquiti and significant for Geophagus proximus. It is concluded that the change in the hydrological regime caused by different stages in construction of the Estreito barrage (river and filling) led to changes in dietary habits in only one of two species of fish of the Cichlidae family in the region. Cichla piquiti presented itself more specialized as to its feed, preserving the two phases of the barrage piscivorous habit as that Geophagus proximus proved to have a greater trophic plasticity, having a greater amount of food items and diversifying them, in the two phases of the barrage, but not diversifying its trophic guild. / A inclus?o de barreiras artificiais em ecossistemas aqu?ticos continentais pode desencadear processos com repercuss?es ecol?gicas, econ?micas e sociais. A plasticidade alimentar ? uma caracter?stica ? adapta??o ao novo ambiente, esperando-se que a alimenta??o de esp?cies de peixes em ambientes modificados acompanhe as mudan?as na disponibilidade de nutrientes do ambiente. Para avaliar se entre as diferentes fases de constru??o da Barragem de Estreito, Rio Tocantins, MA houve diferen?as no h?bito alimentar em duas esp?cies de peixes (Geophagus proximus e Cichla piquiti) da fam?lia Cichlidae, expedi??es de coleta foram realizadas de novembro de 2009 a 2010, (fase rio) e novembro de 2010 a abril 2011(fase enchimento), com dura??o m?dia de 10 dias por campanha. Os itens alimentares de cicl?deos dominantes foram analisados pelo m?todo de freq??ncia de ocorr?ncia e ?ndice volum?trico, combinados no ?ndice de Import?ncia Alimentar (IAI). O ?ndice de Shannon foi usado para avalia??o da diversidade de itens e classifica??o de guilda tr?fica. As diferen?as significativas na amplitude de nicho entre as fases rio e enchimento foram verificadas atrav?s do teste de Hutcheson. Entre os Cicl?deos encontrados na ?rea de influ?ncia da Barragem, Geophagus proximus e Cichla piquiti foram dominantes, com os resultados sugerindo uma dieta on?vora, com predomin?ncia de peixes e algas para a fase rio e de insetos para a fase enchimento. O n?mero de categorias alimentares variou entre 09 na fase rio e 08 na fase enchimento para Ciclha piquiti e entre 14 na fase rio e 12 na fase enchimento para Geophagus proximus. O teste de diferen?a de amplitude de nicho entre as duas fases revelou uma diferen?a n?o significativa para Cichla piquiti e significativa para Geophagus proximus. Conclui-se neste trabalho que a mudan?a no regime hidrol?gico causado pelas diferentes fases de constru??o da Barragem de Estreito (rio e enchimento) causou modifica??es nos h?bitos alimentares das duas esp?cies de peixes da fam?lia Cichlidae da regi?o. Cichla Piquiti revelou-se mais conservativa quanto a sua alimenta??o, apresentando poucas modifica??es em sua dieta nas duas fases da barragem enquanto Geophagus proximus revelou ter uma maior plasticidade tr?fica, tendo uma maior quantidade de itens alimentares e com varia??es nos itens dominantes entre as duas fases da barragem, por?m n?o variando sua guilda tr?fica.